To see the other types of publications on this topic, follow the link: Cichlid fish.
Dissertations / Theses on the topic 'Cichlid fish'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Cichlid fish.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Allender, Charlotte Jane. "Molecular markers and the speciation of African cichlid fish." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394101.
Full text
2
Tyers, Alexandra Morton. "Divergence and speciation of East African haplochromine cichlid fish." Thesis, Bangor University, 2013. https://research.bangor.ac.uk/portal/en/theses/divergence-and-speciation-of-east-african-haplochromine-cichlid-fish(35db9b7b-0775-4cd5-94f3-556a6f3cacd6).html.
Full textAbstract:
In the Great Lakes of the East African Rift Valley, cichlid fishes have diversified into hundreds of species with great variety of ecomorphological, secondary sexual and behavioural characteristics. A strong role for sexual selection in their speciation is indicated by the presence of many closely related ecologically similar sympatric species which differ in male secondary sexual characteristics. A review of previous research finds that reproductive isolation by direct mate choice may be a common isolating barrier among sympatric species. Observations of partial assortative mating among divergent geographic populations have lead to theories of intralacustrine allopatric speciation of habitat specialists by divergence of signal traits involved in conspecific recognition. Here I demonstrate that signal and preference divergence among populations is not limited to patchily distributed lacustrine endemics, but can also occur in the widely distributed riverine generalist lineage that is phylogenetically basal to the large lacustrine radiations, suggesting a role for divergence of secondary sexual traits in allopatry throughout adaptive radiation. This thesis also adds to the evidence for ecological divergence and peripatric speciation of lacustrine habitat specialists in the absence of significant colour differentiation. In simulated intruder choice tests, males tend to bias aggression towards males of their own species or populations, which may aid in the co-existence of allopatrically diverged populations under secondary sympatry and help to facilitate speciation, or even drive divergence of male traits that are involved in signalling during both courtship and territorial interactions. Results from preliminary investigations into individual variation in mate preference suggest that partial assortative mating among allopatric populations may be due to variation within, rather than among, individuals in their choice of mate. Within-individual variation may be unlikely to cause divergence, but has the potential to aid in colonisation of new areas by a relaxation of directional selection allowing for divergence of male traits by environmental or other social selection pressures. To draw any firm conclusions about the impact of variation in mate choice on speciation, much more data from a wider variety of lineages is needed. Mate choice experiments, carried out as part of a larger ongoing project into sympatric divergence of haplochromine cichlids in isolated crater lakes, found little consistency of female mate choice despite morphological and genetic differentiation of forms. This indicates that, in contrast to previously tested sympatric species of cichHds, at the beginnings of adaptive radiation variety may not be maintained solely through reproductive isolation by direct mate choice. Observations of interactions among animals may frequently reveal unexpected results with regards to what is and is not a species - for example, strong assortative mating among phenotypically similar allopatric populations and that assortative mating alone may not maintain diversity in sympatric populations. Behavioural experiments can complement more modern genetic and genomic techniques and therefore continue to be a valuable tool in the study of speciation and the mechanisms involved in divergence and the maintenance of diversity.
3
Ford, A. G. P. "Evolutionary relationships of East African soda lake cichlid fish." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1471875/.
Full textAbstract:
This thesis examines the evolutionary relationships of the Alcolapia soda lake cichlid fishes of East Africa. The introduction presents background on the soda lakes in which the cichlids are found, the taxonomy and biology of the fishes, as well as the theoretical background to the study. Chapter two discusses the methods used in the thesis, addressing the benefits and limitations of each, as well as their suitability to the study in hand. Chapter three investigates the phylogenetics and phylogeography of soda lake cichlids sampled at several populations around the soda lakes and a single transplanted population outside of the focal lakes, employing a large genomic dataset generated through restriction site associated DNA (RAD) sequencing, and demonstrates low levels of interspecific genomic differentiation with high levels of ongoing gene flow. Chapter four uses the RAD dataset to test for signals of selection between Alcolapia species, employing genome-wide scans and outlier detection to characterise peaks of genomic divergence between species. Chapter five combines morphological (geometric morphometrics) and ecological (stable isotope, stomach contents) data with the RAD dataset from chapter three to consider biologically relevant diversification between Alcolapia species, testing for convergence and niche adaptation. Chapter six examines the ecomorphology of the soda lake fishes at an intraspecific level, testing for effects of geography and environment on morphological differentiation between populations. Finally, chapter seven draws together the conclusions inferred from the thesis, and discusses possible future directions for research in this system.
4
Morley, Josephine Isabelle. "Intraspecific competition and monogamy in the cichlid fish, Eretmodus cyanostictus." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621721.
Full text
5
Cooke, Gavan M. "The behavioural ecology of aggression in Lake Malawi haplochromine cichlid fish." Thesis, Bangor University, 2012. https://research.bangor.ac.uk/portal/en/theses/the-behavioural-ecology-of-aggression-in-lake-malawi-haplochromine-cichlid-fish(8a0e6fe2-15b6-42f5-9324-7749b44f3dad).html.
Full textAbstract:
Aggression is ubiquitous in the animal kingdom and a major field of investigation within the area of behavioural ecology. The haplochromine cichlid fish have been used extensively in studies relating not only to the behavioural ecology of aggression but also with respect to how aggression may play a role in the spectacular diversity found within the African Great Lakes. In the first half of this thesis, I investigate the nature of aggression within the rock dwelling fish of Lake Malawi. Aggression biases within polymorphic populations are initially investigated with field work determining the consequences of rare morph advantage. This is followed by experiments determining which cues males and females may use; lastly a pair of recently diverged allopatric species is studied to determine what may happen should secondary contact occur. The second half of this thesis focuses on the behaviorual ecology of female aggression. Females exhibiting the ancestral condition of post brood care are compared to a species with the more derived condition of no post release care. Non-maternal aggression is investigated with comparisons of the type of behavior used by males and females. When and why females are aggressive is also investigated. The results of this thesis suggest that overall a common morph bias may exist in some populations and the consequences are manifested in a rare morph advantage. Colour is important in aggression biases but potentially not limited to the dorsal region. Females and males use different kinds of aggressive behaviors and brooding females are able to vary levels of aggression towards different types of threat.
6
Lee, Terence. "Female ornamentation and intrasexual competition if the convict cichlid fish (Archocentrus Nigrofasciatus)." Diss., Restricted to subscribing institutions, 2007. http://proquest.umi.com/pqdweb?did=1486384711&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.
Full text
7
Booton, Gregory Charles Bonner. "Molecular genetic analysis of the phylogenetic relationships of Lake Victoria Cichlid fish /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487861796817821.
Full text
8
Fan, Shaohua [Verfasser]. "Genome evolution and speciation : insights from cichlid, coelacanth, and Xiphophorus fish / Shaohua Fan." Konstanz : Bibliothek der Universität Konstanz, 2014. http://d-nb.info/108096293X/34.
Full text
9
Dijkstra, Peter Douwe. "Know thine enemy: intrasexual selection and sympatric speciation in Lake Victoria cichlid fish." [S.l. : [Groningen : s.n.] ; University Library Groningen] [Host], 2006. http://irs.ub.rug.nl/ppn/298119005.
Full text
10
Parsons, Paul John. "Ecological constraints on evolution : a case study with Lake Malawi's 'prototype' cichlid fish." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.685151.
Full textAbstract:
Understanding how the environment drives the pattern of adaptive radiation may be key to understanding tl1e role of ecology in evolution. The Lake Malawi Haplochomine cichlid fish radiation was seeded by riverine ancestors, yet extant riverine diversity is extremely low. Only Astatotilapia calliptera the putative ancestor of flock currently persists in both the lake and the rivers of the catchment. This presents us with a useful model for assessing tl1e role of environment in driving diversification within a single species. We predict that the contrast in disturbance regime may drive the difference in speciation rate between the two habitats. In tlus thesis, population genetic analysis, functional morphometries, and common garden experiments are used to investigate the level of variation between disturbed river populations and comparatively stable lake populations. The genetic analysis indicates minimal population structuring between Lake Malawi populations compared to within or between river systems. Morphometric data suggests that lake populations are locally diversifying despite this limited isolation. River morphologies are similar despite reduced mixing. Dietary analysis shows that differences in morphology are functional, with the key axis of variation ranging from hard-bodied animals to smaller non-animal resources. Common garden experiments show a clear trade-off between egg-size and number. The majority of sites including all river sites adopt a more conservative strategy focussing on high offspring number. One lake population adopts a high investment strategy. A comparison between lab reared morphology and wild caught morphologies shows that the majority of variation maintained in the wild is through plastic mechanisms. These results suggest that the unpredictability of the riverine environment constrains populations to bet-hedging strategies whilst the highly competitive nature of the lake promotes specialisation. This selection for specialisation could in turn lead to speciation, and may partly explain why speciation within Lake Malawi has been so spectacular
11
Yakupitiyage, A. "Quantitative and qualitative aspects of energy acquisition of the cichlid fish Oreochromis niloticus L." Thesis, University of Stirling, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234936.
Full text
12
Buckley, Jonathan. "Parental care and the development of the parent offspring conflict in discus fish (Symphysodon spp.)." Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1041.
Full textAbstract:
Parental care has evolved across the animal kingdom to increase the probability of offspring surviving in an environment fraught with danger. While parental care is common among mammals and birds, it is relatively rare in fish with the vast majority of fish showing no form of parental care at all, whilst those that do, often just provide parental care to developing eggs pre-hatch. The provision of parental care in discus fish (Symphysodon spp.) is, therefore, interesting in that parents provide mucus to offspring as a source of nutrition during the first few weeks of care. In mammals this post-birth provision of parental care can lead to the development of the parent offspring conflict. It is, however, possible that this conflict is also present in discus fish. This thesis examines both the interesting parental care strategy of discus fish along with the potential for the parent offspring conflict to develop. To examine the dynamics of parental care in discus fish, a range of behavioural and mucus composition studies were carried out. The analysis of mucus revealed that similar to mammals, parents provided offspring with an initial high quantity of nutritional and non-nutritional factors including antibodies (IgM), essential ions and hormones. Behavioural studies also revealed that initially parents were highly diligent in providing care to offspring but that after two weeks of care, the behaviour of parents changed making it harder for offspring to obtain mucus. At this point a weaning period was initiated where offspring began spending less time with parents and more time foraging for external food sources. The initiation of this weaning period suggests the presence of the parent offspring conflict and indicates that a point is reached where the energetic demands of offspring are too great and that energy is better invested in to future offspring. Research into the bite size and feeding rate of fry suggest that during the weaning period fry could demand excessive amounts of mucus, which may be energetically unsustainable leading to the observed offspring avoiding behaviour of parents. As parental care behaviour is known to be intimately associated with mate choice, mate choice behaviour was also assessed in discus fish with the hypothesis that the ability to provide mucus would be selected for by prospective mates. While my dietary experiment did not influence mucus quality, the mate choice experiment did reveal the importance of hierarchies in discus fish, indicating that dominant individuals were significantly more likely to pair than subordinates. This is similar to that observed in closely related cichlids where the ability to be dominant and protect a territory was indicative of the ability to successfully raise offspring. In conclusion, the parental care behaviour of discus fish appears to share more similarities with that seen in mammals than that observed in fish. The implications of these findings indicate that parental care in discus fish could be a new model of parent offspring conflict hitherto unseen in fish which could ultimately help our understanding of the evolution of parental care in fish.
13
McNeil, Georgia. "Hypoxia, carotenoids, and colour expression in the widespread African cichlid fish Pseudocrenilabrus multicolor victoriae." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110683.
Full textAbstract:
Understanding the role of divergent selection in the creation and maintenance of biodiversity is a central issue in evolutionary ecology. Cichlid fishes from the Great Lakes of East Africa are one of the foremost examples of rapid speciation in vertebrates, and their divergent male colour patterns have been credited with maintaining reproductive isolation. One approach to understanding the role of divergent selection in colour variation and to identify selective agents that may drive divergence, is to explore colour variation among populations of a single species that cross strong physico-chemical or biotic gradients. I apply this approach to examine the role of a divergent factor (low dissolved oxygen) in driving divergence in a sexually selected trait (colour) in the widespread African cichlid fish Pseudocrenilabrus multicolor victoriae. Specifically, I integrated a field survey of P. multicolor to describe natural variation in colour patterns across oxygen gradients with a laboratory rearing experiment to quantify the interaction of low oxygen (hypoxia) and diet on expression of male colour during development. My results show significant differences in male P. multicolor nuptial colouration across dissolved oxygen gradients in the field: high-oxygen populations had more yellow, while low-oxygen populations had more red colour. Results of the laboratory rearing study on F1 offspring from a population of river origin showed that diet, i.e. carotenoid availability, is important for colour production during development; however, diet alone could not account for all observed colour variation in the lab or field. These results suggest that dissolved oxygen availability, or other factors correlated with oxygen may contribute to male colouration in P. multicolor in the field. I discuss these results and integrate them into a larger framework that describes potential explanations for the development of this colour divergence.Comprendre l'apport de la sélection divergente à la création et au maintien de la biodiversité constitue un des enjeux principaux de l'écologie évolutive. Les poissons cichlidés des grands lacs d'Afrique de l'Est constituent un exemple bien connu de spéciation rapide où les différences interspécifiques de patrons de couleurs maintiennent les barrières reproductives entre les espèces. Une des approches permettant l'analyse du rôle de la sélection divergente dans la création de cette diversité de colorations est de mesurer la variation de couleurs entre plusieurs populations d'une même espèce dispersées le long de gradients physico-chimiques ou biotiques forts. J'ai utilisé cette approche pour examiner le rôle joué par un facteur environnemental (la concentration d'oxygène dissout dans l'eau) dans la variation des traits reproductifs (dans ce cas, la coloration nuptiale) entre différentes populations d'un poisson cichlidé haplochromine. Plus spécifiquement, j'ai combiné un échantillonnage de terrain à une expérience d'élevage en laboratoire pour quantifier les effets combinés de la diète et de l'hypoxie sur la coloration du cichlidé Pseudocrenilabrus multicolor victoriae. Les résultats de cette étude sont les premiers à montrer que l'oxygène dissout influence la coloration nuptiale chez P. multicolor : les mâles des populations habitant des eaux riches en oxygène sont plus jaunes alors que les mâles des populations venant d'eaux pauvres en oxygène sont plus rouges. Les résultats de l'expérience d'élevage en laboratoire montrent que la diète influence elle aussi la coloration nuptiale chez P. multicolor; par contre, les différences alimentaires ne suffisent pas à elles seules à expliquer la variation de coloration observable en laboratoire ou en milieu naturel. Résultats de l'étude d'élevage en laboratoire sur les progénitures F1 d'une population d'origine rivière a montré que le régime alimentaire (c'est-à-dire le quantité de caroténoïdes disponible), est important pour la production de la couleur au cours du développement, mais un régime alimentaire seul ne pourrait pas expliquer toutes les variations de couleur observée dans le laboratoire ou sur le terrain. Ces résultats suggèrent que l'hypoxie pourrait induire un mécanisme compensatoire résultant en une variation dans les patrons de couleurs entre les habitats riches et pauvres en oxygène dissout. Je discute ici ces résultats et les intègre dans un contexte plus large qui décrit une explication potentielle pour l'existence de cette divergence en coloration.
14
Nelson, John. "The maternal and parental behaviour of the African cichlid fish Pelvicachromis pulcher (Boulenger, 1901)." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286831.
Full text
15
Doggett, Teresa Ann. "The structure and function of peripheral blood leucocytes and gut-associated lymphoid tissue in the cichlid, Oreochromis mossambicus." Thesis, University of Plymouth, 1989. http://hdl.handle.net/10026.1/2776.
Full textAbstract:
The peripheral blood of O.mossambicus was examined using light and electron microscopy and was found to contain four forms of leucocytes: lymphocytes, thrombocytes, monocytes and three types of granulocytes. The monocyte and two types of granulocyte were found to be phagocytic and ingest colloidal carbon and bacteria. The alimentary tract was found to contain a number of leucocytes, some showing a morphological similarity to those in the peripheral blood, while others were unique to the gut tissue. These intestinal leucocytes were found mainly as a diffuse cell population in the epithelium and lamina propria, and only occasionally as discrete lymphoid accumulations within the gut tissue. Ontogenic studies showed that a limited number of leucocytes were found in the gut tissue after hatching, however, there was a gradual increase in these numbers once exogenous feeding began. The intestinal enterocytes of both the anterior and posterior intestine were found to take up intubated macromolecules. An electron microscopical investigation revealed that these macromolecules were absorbed by pinocytosis and were found within large intraepithelial macrophages. These macromolecules were also absorbed and transported into the systemic circulation. In juvenile fish macromolecules were detected in the plasma following both oral and anal intubation, however, in adult fish they were detected in the plasma only after anal intubation, and in smaller quantities. Macromolecular absorption in O.mossambicus was compared to that in two other fish species, Cyprinus carpio and Sa1mo gairdneri, and it was found that higher levels of absorbed macromolecules were found in the plasma of O.mossambicus. Bovine serum albumin absorption by the gut of the three species revealed that both the 'intact' macromolecule and smaller antigenic fragments, probably resulting from enzymatic modification, were ansorbed and transported into the plasma.
16
Jambo, Collins Mayeso. "Aspects of the ecology and reproductive biology of three cichlid fish species of Southern Lake Malombe (Malawi)." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005067.
Full textAbstract:
The three major species Lethrinops ''pinkhead'', Otopharynx argyrosoma "red" and Copadichromis. cf virginalis which used to dominate the catches (by weight) of Lake Malombe in the past decade were investigated. In order to make rational recommendations regarding size and boundary of the existing sanctuary area (lightly fished), distribution and abundance, population structure and reproductive biology of the three species were related to habitat types of the southern part of the lake (south western side and south eastern side). Analysis of catch composition showed that species richness was higher in the south eastern side than in the south western side of the lake. Rare species such as Labeo mesops and Opsaridium microiepis were observed in the south eastern side and there was visual absence of such species in the south western side of the lake. The overall fish abundance was significantly greater in the south eastern side than in the south western side of the lake. In the south eastern side, the catch per unit effort (CPUE) was twice that of the south western side (P< 0.05). Seasonal fluctuations in CPUE were also prominent, with the highest peak occurring during September-October period. However, there was an indication of weak relationship among CPUE, phytoplankton biomass, temperature and water depth. The length-weight relationships revealed that growth of the three species closely followed the cubic law for isometric growth in both sides of the lake. Differences in regression coefficients between sides were not significant (ttest, P>0.05). The length-frequency distribution analysis revealed that the three species had the same growth rate regardless of habitat type. However, females grew faster than males. An investigation of reproductive biology showed that the three species have low fecundity and they are asynchronous spawners, with a breeding peak during August and September period. Furthermore, the length-fecundity relationships for L. ''pinkhead'', and 0. argyrosoma "red" indicated that fecundity was more closely related to length in the south eastern side than in the south western side. Based on the above characteristics of L. ''pinkhead'', 0. argyrosoma "red" and C. cf virginalis, and the substrate types, it was strongly suggested that the existing sanctuary (lightly fished) in the south eastern side of the lake could immediately be enlarged to conserve the fish stocks, favourable substratum and aquatic animals that may be of tourists concern.
17
Lorenz, O. Thomas. "Effects of interspecific competition, salinity, and hurricanes on the success of an invasive fish, the Rio Grande cichlid (Herichthys cyanoguttatus)." ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/846.
Full textAbstract:
The Rio Grande cichlid (Herichthys cyanoguttatus) has been established in the Greater New Orleans Metropolitan Area (GNOMA) for at least 20 years. It is often the most common fish species in urban canals and has also been found in natural waterways outside of the GNOMA. The effects and potential for further spread of H. cyanoguttatus is uncertain. My research addressed how extensive the cichlids spread in the GNOMA, how H. cyanoguttatus interacted with L. macrochirus, a native fish, and what salinity tolerance this species has. Surveys on Lake Pontchartrain and in the GNOMA indicated that H. cyanoguttatus is well established in urban habitats. These surveys also indicate that H. cyanoguttatus has spread rapidly into Bayou Saint John and City Park in recent years and that H. cyanoguttatus populations were relatively unaffected by Hurricanes Katrina and Rita. There is little evidence that H. cyanoguttatus has become established outside of the GNOMA, but this lack of persistence cannot be explained by abiotic variables I measured. Salinity may be a factor and this was measured in growth trials of H. cyanoguttatus. Salinities up to 16 ppt, however, had no significant effect on H. cyanoguttatus growth. Interspecific behavioral experiments were conducted to examine potential biotic interactions with native fish species. Prior resident trials indicated that H. cyanoguttatus was aggressive whether holding territory or not, and that native bluegill (Lepomis macrochirus) was only aggressive while holding territory. Feeding experiments were performed to examine biotic interactions between H. cyanoguttatus and L. macrochirus. Lepomis macrochirus grew faster than H. cyanoguttatus when inter- and intraspecific trials were compared; however, no significant growth differences were seen when trials were structured with L. macrochirus as prior residents. The major findings of my research are a high salinity tolerance of H. cyanoguttatus, a potential mechanism for H. cyanoguttatus affecting native fishes through aggression as residents and invaders, and the presence of H. cyanoguttatus throughout the GNOMA, before and after the hurricanes.
18
Pineda, Lopez Raul Francisco. "Ecology of the helminth communities of cichlid fish in the flood plains of Southeastern Mexico." Thesis, University of Exeter, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386308.
Full text
19
Arpin, Sheree. "Using Mathematical Models to Investigate Phenotypic Oscillations in Cichlid Fish: A Case of Frequency-dependent Selection." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195981.
Full textAbstract:
Perissodus microlepis is a species of cichlid fish endemic to Lake Tanganyika (Africa). Adult P. microlepis are lepidophages, feeding on the scales of other living fish. As an adaptation for this feeding behavior P. microlepis exhibit lateral asymmetry with respect to jaw morphology: the mouth either opens to the right or left side of the body. Field data illustrate a temporal phenotypic oscillation in the mouth-handedness, and this oscillation is maintained by frequency-dependent selection. To better understand the oscillation, Takahashi and Hori model frequency-dependent selection in P. microlepis using a population genetic model. Their results are intriguing, and the purpose of this dissertation is to improve and extend their model, which fails to account for important biological aspects.We model P. microlepis with a novel approach that fuses the disparate modeling traditions of population genetics and population dynamics; we account for both processes since, in the case of P. microlepis, they occur on the same time scale (a case of microevolution). We construct our models using systems of difference equations. We prove the existence and uniqueness of a positive equilibrium, which corresponds to a 1 : 1 phenotypic ratio. Using a local stability and bifurcation analysis, we show that the equilibrium becomes unstable when frequency-dependent selection is sufficiently strong. We determine necessary and sufficient conditions for onset of oscillation. Local bifurcation analysis indicates key features of the oscillation that may suggest critical experiments.We determine the role of stage structure and the role of strong and weak intraspecific competition. We show that stage-structure is not necessary for, but enhances, oscillatory behavior. Finally we demonstrate the complicated interplay between population dynamic and population genetic processes. Our findings indicate that classical population genetic models can fail to elucidate complex dynamics.
20
Chan, Tin-Yam. "The role of male competition and female choice in the mating success of a Lek-breeding Southern African Cichlid fish Pseudocrenilabrus Philander (Pisces: Cichlidae)." Thesis, Rhodes University, 1988. http://hdl.handle.net/10962/d1002049.
Full textAbstract:
A lek-breeding cichlid fish Pseudocrenilabrus philander was studied experimentally. Females in choice-chamber experiments showed no active choice for male size and colour, or for other male attributes, but preferred males which courted most actively. In a laboratory lek, the significant determinants of the strongly skewed mating success in males were territory size, side-shake and female chasing frequency. Together these three variables explained 79% of the variation in male mating success, with territory size alone accounting for 75% of the variation and the other two variables each accounting for 2% of the remaining variation. As there was no difference in territory quality in the laboratory lek, territory size became the principal measure of the effect of male-male competition since it was directly related to dominance. Both side-shake and female chasing could be identified as the basic factors influencing female choice, as they had an immediate effect on the display-response mating system of females. Thus, the relative importance of these three variables indicated that sexual selection in this particular lek mating species operated chiefly through the agency of intrasexual competition for dominance. However, both female behaviour and their requirement for a prolonged pre-spawning courtship had the effect of promoting male rivalry and favouring mating with dominant males. Although the intense male competition excluded subordinate males from practising normal courtship behaviour, competitively inferior males might "make the best of a bad situation" by facultatively adopting an alternative sneaking tactic to gain access to females. Spawning intrusions by females to steal freshly-laid eggs also occurred frequently. However, territorial males appeared to be relatively more tolerant of female intruders than male sneakers. Interference during spawning could lead to a longer pre-spawning courtship and even multiple-mating by females. The results of the present study and the behavioural evidence shown by males and females did not support the ʺrunaway selection modelʺ of the mating pattern in terms of sexual selection in leks, but conformed to the rival ʺwar propaganda modelʺ
21
Jehangir, Maryam. "Genome assembly of the cichlid fish Astatotilapia latifasciata with focus in population genomics of B chromosome polymorphism." Botucatu, 2017. http://hdl.handle.net/11449/151740.
Full textAbstract:
Orientador: Cesar MartinsResumo: B chromosomes (Bs) are additional to the standard regular chromosome set (As), and present in all groups of eukaryotes. A reference genome is key to understand genomics aspects of an organism. Here, we present the de novo genome assembly of the cichlid fish A. latifasciata: a well known model to study Bs. The assembly of A. latifasciata genome has not been performed so far. The main focus of this study is to analyze and assemble the A. latifasciata genome with no B (B-) and with B (B+) chromosomes. The assembled draft B- and B+ genomes comprised of 774 Mb and 781 Mb with 1.8 Mb and 2.5Mb of N50 value of scaffolds respectively, and spanning 23,391 number of genes. High coverage data with Illumina sequencing was obtained for males and females with 0B, 1B and 2B chromosomes to provide information regarding the population polymorphism of these genomes. We observed a high scale genomic diversity in all analyzed genomes showing a high rate/frequency of population polymorphism with no evident effect of B chromosome presence. However, the B specific single nucleotide polymorphisms were found in the sequences that were located on B chromosome. While, the whole-genome rearrangements (inter chromosomal translocations) were detected in B+ genome, and structural variations including insertions, deletions, inversions and duplications were predicted in a representative genomic region of B chromosome. These results bring an evidence that existence of Bs in a genome should favour the accumu... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre
22
Atkinson, Tiffany L. "Living in a haze: Direct and indirect impacts of turbidity and diet on an African cichlid fish." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1555434028656478.
Full text
23
Sefton, Margaret [Verfasser]. "Investigating the developmental and gene regulatory basis of color diversification in cichlid fish : A framework for evolutionary developmental studies in the Midas cichlid species complex (Amphilophus spp.) / Margaret Sefton." Konstanz : Bibliothek der Universität Konstanz, 2017. http://d-nb.info/1172634904/34.
Full text
24
Oldham, Richard Cole. "Environmental differences affect the visual ecology of an African cichlid (Pseudocrenilabrus multicolor victoriae)." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152572108599038.
Full text
25
Binning, Sandra. "Specialized morphology for a generalist diet: spatial and seasonal surveys reveal Liem's Paradox in an African cichlid fish." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32395.
Full textAbstract:
Ecomorphology is founded on the premise that ecological interactions are reflected in adaptive morphological change across individuals, populations, and communities. Specialization in feeding structures is often used to describe and classify species and is believed to be an important mechanism driving speciation in a number of taxa including Darwin's finches, Caribbean labrid fishes, and African cichlid fishes. However, morphology and ecology are not always tightly linked, and a number of studies have shown species with specialized morphologies consuming primarily generalist diets, a phenomenon known as Liem's Paradox. In this thesis, I use both spatial (interdemic) and seasonal studies to explore Liem's Paradox in natural populations of the specialized "molluscivorous" African cichlid, Astatoreochromis alluaudi. In an interdemic study, I quantified relationships among diet, morphology and the environment in A. alluaudi from six sites in Uganda. Pharyngeal jaw and muscle morphology differed among populations, with jaw traits explaining most of the variation. Similarly, I found differences in diets among sites; mollusks were rare, found in the stomachs of only two populations sampled. Trophic morphology did match the observed diet in two sites, but diet did not correlate with either morphology or environmental variables across the six sites. The absence of tight links among morphology, diet, and prey abundance among populations of A. alluaudi is consistent with Liem's Paradox. To examine whether a mismatch between diet and morphology occurs seasonally or chronically in populations of A. alluaudi, I used a seasonal survey of diet at Lake Saka, a site where A. alluaudiL'écomorphologie est fondée sur le principe que les changements morphologiques adaptatifs observés chez certaines espèces, populations et communautés sont un produit des interactions écologiques en milieu naturel. La spécialisation de structures trophiques est souvent utilisée comme critère pour décrire et classifier des espèces et est également invoquée comme un mécanisme responsable de la spéciation d'une variété d'organismes incluant les pinsons de Darwin, les poissons Labridae des Caraïbes et les cichlidés africains. Cependant, la morphologie et l'écologie d'une espèce ne sont pas toujours liées. Plusieurs études ont démontré que des espèces possédant une morphologie trophique spécialisée s'alimentent souvent de façon généraliste, un phénomène surnommé le paradoxe de Liem. Cette thèse se base sur un échantillonnage spatial et temporel afin d'étudier le paradoxe de Liem en milieu naturel, dans des populations d'un cichlidé africain, Aststoreochromis alluaudi, ayant une morphologie adaptée pour se nourrir de mollusques. À travers six sites en Ouganda, j'ai quantifié les relations entre l'alimentation, la morphologie, et certaines variables environnementales importantes pour cette espèce. Mes résultats démontrent que la morphologie de la mâchoire pharyngale et des muscles trophiques de A .allaudi est différente entre populations, et que la morphologie de la mâchoire explique un grand pourcentage de la variance. L'alimentation de A. allaudi est également différente entre sites et le cichlidé se nourrit de mollusques dans seulement deux des six sites échantillonnés. De plus, la morphologie trophique correspond à l'al
26
Raffini, Francesca [Verfasser]. "Exploring the origin and maintenance of biodiversity : insights from the bilaterally asymmetrical cichlid fish Perissodus microlepis / Francesca Raffini." Konstanz : Bibliothek der Universität Konstanz, 2018. http://d-nb.info/1153712504/34.
Full text
27
Kim, Lesley Yu-Jung. "Effect of increased temperature and decreased food quality on metabolism and growth of an algivorous cichlid, Tropheus duboisi and effect of food habit on the field metabolism of African Cichlids." Wright State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=wright1409625207.
Full text
28
Ims, Stine. "The Efficacy and Stress-Reducing Capacity of MS-222, Benzoak and Aqui-S for the Ornamental Cichlid Fish, Metriaclima estherae." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12760.
Full textAbstract:
The financial crises and global change have caused setbacks to the improvements in many undeveloped countries. To be able to achieve the Millennium developmental goals within 2015, it will require a higher effort. Sub-Saharan African countries show the slowest economic growth and have experienced the highest setbacks. Malawi is one of these countries and is struggling with a high share of poverty and poverty related issues. Trade is believed to be the most prominent tool to fight world poverty, as it will provide economic growth and employment. Cichlid fishes from Lake Malawi are popular ornamentals for hobby aquarists world wide, representing yearly turnover of 340 million US dollars. It is suggested that ornamental Malawi cichlids can be developed into an industry benefiting country and the local poor people. This can be achieved without pressure upon the lake biodiversity if the wild-collected fishes are used for breeding purpose and not for export. To be able to deliver a high quality fish, it will be necessary to establish proper handling strategies that will ensure fish health and welfare. Stress from handling procedures is known to have negative impact on fish growth, reproduction, immune function and survival. Anesthetics may be a useful tool during handling procedures of the fish, as it can reduce the perception of the stressor and thus prevent activation of the hypothalamus-pituitary-interrenal (HPI) axis. In this study the three commercial anesthetics; MS-222, Benzoak® and Aqui-S were evaluated for; (1) anesthetic efficacy, (2) safety margin, (3) prolonged exposure and (4) stress-reducing capacity on the Malawi cichlid, red zebra (Metriaclima estherae). The overall results show that concentration of 150 mg/L MS-222, 120 mg/L Benzoak® and 50 mg/L Aqui-S gave satisfying introduction and recovery time for anesthesia. Both MS-222 and Aqui-S gave high safety margins as no fish mortality was recorded after anesthetic exposure for 30 minutes. Benzoak® gave a lower safety margin as there was recorded 50 % mortality following 10 minutes exposure. High mortality rate and sign of insufficient blockage upon the red zebra fish, suggested that prolonged exposure to the tested sedative dosages did not benefit the fish. MS-222 exposure reduced the stress response while Benzoak® and Aqui-S seemed to self-induce an increase in plasma cortisol concentration after anesthetic exposure. In conclusion; for short-term treatment on red zebra fish, a concentration of 150 mg/L MS-222 is recommended.
29
Munubi, Renalda Nanziga. "Algal quality controls the distribution, behavior and growth of algivorous cichlids in Lake Tanganyika." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1453230220.
Full text
30
Hart, Laura J. "Subacute immunotoxic effects of the environmental contaminants 7,12-dimethylbenzanthracene (DMBA), hexachlorocyclohexane (lindane), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on spleen and pronephros cellularity and morphology and functional activity of macrophages contained in these hemotopoietic organs in the cichlid fish tilapia (Oreochromis niloticus)." Thesis, This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-09182008-063320/.
Full text
31
Hellmann, Jennifer K. "Neighbor Effects: The Influence of Colony-level Social Structure on Within-group Dynamics in a Social Fish." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1464129648.
Full text
32
Sodsuk, Panom Krachangpoj. "Molecular genetics and systematics of tilapiine cichlids using allozymes and morphological characters." Thesis, University of Stirling, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385126.
Full text
33
Winkelmann, Kai. "Of large and small fish : testing ecological speciation in Lake Tanganyika cichlids." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633437.
Full textAbstract:
A central question in evolutionary biology is how do new species evolve? Recent advances stem from studies of ecological speciation, where reproductive isolation among incipient species is promoted by divergent adaptation to local habitats. The cichlid fish Telmatochromis temporalis from Lake Tanganyika has evolved two ecologically distinct ecomorphs that occupy different habitats, with large bodied fish on rock habitat, and small bodied fish on shell-bed habitat. It has been suggested that the diversification of these two ecomorphs has taken place repeatedly and has been driven by ecological processes. In this thesis population genetic and phylogenetic analyses are presented of geographically-distinct populations. The results provide evidence for a repeatedly and independently-derived adaptation from rock to shell bed habitat, consistent with parallel evolution. Demographic expansions of most populations and splitting time estimates indicate that the age of habitat and hence habitat availability is vital in shaping population dynamics and evolutionary trajectories. A series of behavioural studies on wild caught fish demonstrated that body-size dependent competition is a fundamental mechanism that determines habitat use and mediates assortative mating in laboratory conditions. The extent of phenotypic plasticity in ecomorph-specific trait evolution was studied under controlled laboratory conditions on first generation offspring. The results suggest that absolute body size is subject to plasticity in both ecomorphs but size at sexual maturity is strongly heritable, with the shell ecomorph maturing at smaller body size. Overall these findings demonstrate how extrinsic factors and divergent selection continue to shape the evolution of novel phenotypes and genotypes in T. temporalis, despite ongoing genetic exchange between diverging lineages.
34
Ribeiro, Heraldo Brum. "Estrutura e evolução cariotípica de peixes ciclídeos sul americanos /." Botucatu : [s.n.], 2007. http://hdl.handle.net/11449/87554.
Full textAbstract:
Orientador: Cesar MartinsBanca: Antonio Carlos Bertollo
Banca: Claudio Oliveira
Resumo: Os ciclídeos são considerados peixes secundários adaptados à água doce e distribuídos principalmente pela África, América Central e América do sul. Nesse trabalho foram realizados estudos citogenéticos em 24 espécies representantes das principais subfamílias de ciclídeos sul-americanos com o objetivo de fornecer contribuições ao entendimento das tendências que governam a evolução cromossômica no grupo. Para isto foram realizadas análises da macroestrutura cariotípica através de coloração convencionais com Giemsa, localização das regiões organizadoras de nucléolo (RONs) através de coloração com Nitrato de Prata e identificação de regiões heterocromáticas através de bandamento C. A análise da macroestrutura cariotípica revelou que, embora eventos de rearranjos cromossômicos ocorreram no grupo, os ciclídeos mantém ainda as características basais do cariótipo dos Perciformes composto por 48 cromossomos subtelo-acrocêntricos. As RONs estiveram presentes em um único par cromossômico, porém em posições variáveis, caracterizando a ocorrência de rearranjos envolvendo estes cromossomos. Embora blocos de heterocromatina tenham sido identificados principalmente no centrômero de todas as espécies analisadas, algumas espécies apresentaram grandes segmentos heterocromáticos intersticiais caracterizando eventos de ganhos de heterocromatina que levaram a diferenciação de cariótipos específicos. As análises citogenéticas realizadas mostram que, embora aparentemente conservada, a estrutura cariotípica dos ciclídeos tem sofrido inúmeros rearranjos ao longo da sua história evolutiva.
Abstract: Cichlids are considered secondary fish adapted to the freshwater and distributed mainly in Africa, Central America and South America. Cytogenetic studies in 24 representative species of the main subfamilies of South American cichlids were conducted with the objective to supply informations about the chromosome evolution in the group. The karyotype macrostructure was analized through Giemsa stainning an localization of the nucleolar organizer regions (NORs) through silver staining technique and the identification of heterochromatic regions through C-banding. The analysis of the karyotype macrostructure showed that although events of chromosome rearrangements occurred in the group, the cichlids still mantain the basic karyotype structure of Perciformes with 48 subtelocentric and acrocentric chromosomes. The NORs were observed in only one chromosome pair, however in different positions, characterizing the occurrence of rearrangements involving the NOR-bearing chromosomes. Although heterochromatic blocks have been mainly identified in centromeres of all analyzed species, some species presented large interstitial heterochromatin segments characterizing events of heterochromatin accumulation that had lead to the differentiation of specific karyotypes. Although the cytogenetic data obtained showed an apparently conserved chromosome structure, the cichlid karyotipes have suffered rearrangements throughout its evolutionary history.
Mestre
35
Ribeiro, Heraldo Brum [UNESP]. "Estrutura e evolução cariotípica de peixes ciclídeos sul americanos." Universidade Estadual Paulista (UNESP), 2007. http://hdl.handle.net/11449/87554.
Full textAbstract:
Made available in DSpace on 2014-06-11T19:22:55Z (GMT). No. of bitstreams: 0
Previous issue date: 2007-03-30Bitstream added on 2014-06-13T19:28:26Z : No. of bitstreams: 1
ribeiro_hb_me_botib.pdf: 818945 bytes, checksum: 0dcdc893d82479fdd59b8e9e10c78d34 (MD5)Universidade Estadual Paulista (UNESP)
Os ciclídeos são considerados peixes secundários adaptados à água doce e distribuídos principalmente pela África, América Central e América do sul. Nesse trabalho foram realizados estudos citogenéticos em 24 espécies representantes das principais subfamílias de ciclídeos sul-americanos com o objetivo de fornecer contribuições ao entendimento das tendências que governam a evolução cromossômica no grupo. Para isto foram realizadas análises da macroestrutura cariotípica através de coloração convencionais com Giemsa, localização das regiões organizadoras de nucléolo (RONs) através de coloração com Nitrato de Prata e identificação de regiões heterocromáticas através de bandamento C. A análise da macroestrutura cariotípica revelou que, embora eventos de rearranjos cromossômicos ocorreram no grupo, os ciclídeos mantém ainda as características basais do cariótipo dos Perciformes composto por 48 cromossomos subtelo-acrocêntricos. As RONs estiveram presentes em um único par cromossômico, porém em posições variáveis, caracterizando a ocorrência de rearranjos envolvendo estes cromossomos. Embora blocos de heterocromatina tenham sido identificados principalmente no centrômero de todas as espécies analisadas, algumas espécies apresentaram grandes segmentos heterocromáticos intersticiais caracterizando eventos de ganhos de heterocromatina que levaram a diferenciação de cariótipos específicos. As análises citogenéticas realizadas mostram que, embora aparentemente conservada, a estrutura cariotípica dos ciclídeos tem sofrido inúmeros rearranjos ao longo da sua história evolutiva.
Cichlids are considered secondary fish adapted to the freshwater and distributed mainly in Africa, Central America and South America. Cytogenetic studies in 24 representative species of the main subfamilies of South American cichlids were conducted with the objective to supply informations about the chromosome evolution in the group. The karyotype macrostructure was analized through Giemsa stainning an localization of the nucleolar organizer regions (NORs) through silver staining technique and the identification of heterochromatic regions through C-banding. The analysis of the karyotype macrostructure showed that although events of chromosome rearrangements occurred in the group, the cichlids still mantain the basic karyotype structure of Perciformes with 48 subtelocentric and acrocentric chromosomes. The NORs were observed in only one chromosome pair, however in different positions, characterizing the occurrence of rearrangements involving the NOR-bearing chromosomes. Although heterochromatic blocks have been mainly identified in centromeres of all analyzed species, some species presented large interstitial heterochromatin segments characterizing events of heterochromatin accumulation that had lead to the differentiation of specific karyotypes. Although the cytogenetic data obtained showed an apparently conserved chromosome structure, the cichlid karyotipes have suffered rearrangements throughout its evolutionary history.
36
Britzke, Ricardo [UNESP]. "Relações filogenéticas do gênero Apistogramma (Teleostei, Cichlidae) e filogeografia da espécie Apistogramma agassizi." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/139333.
Full textAbstract:
Made available in DSpace on 2016-06-07T17:12:09Z (GMT). No. of bitstreams: 0
Previous issue date: 2015-02-26. Added 1 bitstream(s) on 2016-06-07T17:16:42Z : No. of bitstreams: 1
000864243_20170305.pdf: 7143919 bytes, checksum: caed29775e1aef81d31c7ee53b951b52 (MD5) Bitstreams deleted on 2017-03-10T13:07:29Z: 000864243_20170305.pdf,. Added 1 bitstream(s) on 2017-03-10T13:08:14Z : No. of bitstreams: 1
000864243.pdf: 17228237 bytes, checksum: e60fc4adb3f71274c66a6fc0677f3dea (MD5)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Introduction: Prematurity is the leading cause of neonatal mortality and serious neonatal morbidity worldwide and the risk is inversely proportional to gestational age at birth. Several studies demonstrate the role of innate immune response and Toll-like receptors (TLRs) in normal and complicated pregnancies, however most studies have focused on the tissues of the maternal-fetal interface. Research of the expression of TLRs in gestational tissues is of great importance for understanding the involvement of innate immunity in normal pregnancies and adverse pregnancy outcomes, but the analysis of these tissues allows for results only after the complete resolution of gestation. In this scenario, a potential biological sample of interest for analysis of TLRs in the ongoing gestation are maternal peripheral blood cells, since they play a crucial role in the immune system and express high levels of many of the TLRs. Main: Evaluate the profile of gene expression of TLR-1, -2, -4 and -6 in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) and compare these expressions between preterm and term pregnancies. Materials and methods: 119 normal pregnant women were included in the study, subdivided into three groups according to the gestational trimester. In addition, 20 pregnant women in preterm labor and 18 pregnant women at term were evaluated. Gene expression analysis was performed by real-time PCR and protein expression evaluation by flow cytometry. Statistical analyses were performed using the nonparametric Kruskal-Wallis and Mann-Whitney tests by SigmaStat 3.1 software. Results: Regarding PBMCs, there were no significant differences in gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 among the trimesters. The same was observed when comparing PBMCs of preterm and term pregnancies. In relation to neutrophils, gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 remained unchanged throughout normal...
Introduction: Prematurity is the leading cause of neonatal mortality and serious neonatal morbidity worldwide and the risk is inversely proportional to gestational age at birth. Several studies demonstrate the role of innate immune response and Toll-like receptors (TLRs) in normal and complicated pregnancies, however most studies have focused on the tissues of the maternal-fetal interface. Research of the expression of TLRs in gestational tissues is of great importance for understanding the involvement of innate immunity in normal pregnancies and adverse pregnancy outcomes, but the analysis of these tissues allows for results only after the complete resolution of gestation. In this scenario, a potential biological sample of interest for analysis of TLRs in the ongoing gestation are maternal peripheral blood cells, since they play a crucial role in the immune system and express high levels of many of the TLRs. Main: Evaluate the profile of gene expression of TLR-1, -2, -4 and -6 in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) and compare these expressions between preterm and term pregnancies. Materials and methods: 119 normal pregnant women were included in the study, subdivided into three groups according to the gestational trimester. In addition, 20 pregnant women in preterm labor and 18 pregnant women at term were evaluated. Gene expression analysis was performed by real-time PCR and protein expression evaluation by flow cytometry. Statistical analyses were performed using the nonparametric Kruskal-Wallis and Mann-Whitney tests by SigmaStat 3.1 software. Results: Regarding PBMCs, there were no significant differences in gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 among the trimesters. The same was observed when comparing PBMCs of preterm and term pregnancies. In relation to neutrophils, gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 remained unchanged throughout normal ...
FAPESP: 11/00269-4
37
Britzke, Ricardo. "Relações filogenéticas do gênero Apistogramma (Teleostei, Cichlidae) e filogeografia da espécie Apistogramma agassizi /." Botucatu, 2015. http://hdl.handle.net/11449/139333.
Full textAbstract:
Orientador: Claudio de OliveiraCoorientador: Jonathan Stuart Ready
Banca: Anderson Luis Alves
Banca: Luiz Henrique Garcia Pereira
Banca: Guilherme José da Costa
Banca: Ricardo Cardoso Benine
Resumo: Introduction: Prematurity is the leading cause of neonatal mortality and serious neonatal morbidity worldwide and the risk is inversely proportional to gestational age at birth. Several studies demonstrate the role of innate immune response and Toll-like receptors (TLRs) in normal and complicated pregnancies, however most studies have focused on the tissues of the maternal-fetal interface. Research of the expression of TLRs in gestational tissues is of great importance for understanding the involvement of innate immunity in normal pregnancies and adverse pregnancy outcomes, but the analysis of these tissues allows for results only after the complete resolution of gestation. In this scenario, a potential biological sample of interest for analysis of TLRs in the ongoing gestation are maternal peripheral blood cells, since they play a crucial role in the immune system and express high levels of many of the TLRs. Main: Evaluate the profile of gene expression of TLR-1, -2, -4 and -6 in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) and compare these expressions between preterm and term pregnancies. Materials and methods: 119 normal pregnant women were included in the study, subdivided into three groups according to the gestational trimester. In addition, 20 pregnant women in preterm labor and 18 pregnant women at term were evaluated. Gene expression analysis was performed by real-time PCR and protein expression evaluation by flow cytometry. Statistical analyses were performed using the nonparametric Kruskal-Wallis and Mann-Whitney tests by SigmaStat 3.1 software. Results: Regarding PBMCs, there were no significant differences in gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 among the trimesters. The same was observed when comparing PBMCs of preterm and term pregnancies. In relation to neutrophils, gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 remained unchanged throughout normal...
Abstract: Introduction: Prematurity is the leading cause of neonatal mortality and serious neonatal morbidity worldwide and the risk is inversely proportional to gestational age at birth. Several studies demonstrate the role of innate immune response and Toll-like receptors (TLRs) in normal and complicated pregnancies, however most studies have focused on the tissues of the maternal-fetal interface. Research of the expression of TLRs in gestational tissues is of great importance for understanding the involvement of innate immunity in normal pregnancies and adverse pregnancy outcomes, but the analysis of these tissues allows for results only after the complete resolution of gestation. In this scenario, a potential biological sample of interest for analysis of TLRs in the ongoing gestation are maternal peripheral blood cells, since they play a crucial role in the immune system and express high levels of many of the TLRs. Main: Evaluate the profile of gene expression of TLR-1, -2, -4 and -6 in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear cells (PMNs) and compare these expressions between preterm and term pregnancies. Materials and methods: 119 normal pregnant women were included in the study, subdivided into three groups according to the gestational trimester. In addition, 20 pregnant women in preterm labor and 18 pregnant women at term were evaluated. Gene expression analysis was performed by real-time PCR and protein expression evaluation by flow cytometry. Statistical analyses were performed using the nonparametric Kruskal-Wallis and Mann-Whitney tests by SigmaStat 3.1 software. Results: Regarding PBMCs, there were no significant differences in gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 among the trimesters. The same was observed when comparing PBMCs of preterm and term pregnancies. In relation to neutrophils, gene and protein expressions of TLR-1, TLR-2, TLR-4 and TLR-6 remained unchanged throughout normal ...
Doutor
38
Narcizo, Amanda de Moraes. "Avaliação da exposição aguda ao alumínio e variações do pH na expressão de gonadotropinas em Oreochromis niloticus (Teleostei: Cichlidae)." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-16102009-160951/.
Full textAbstract:
O alumínio e o pH ácido exercem efeitos tóxicos sobre a fauna íctica. O objetivo deste trabalho foi avaliar os efeitos do alumínio e do alumínio em pH ácido na fisiologia reprodutiva de Oreochromis niloticus. Para a condução deste experimento, fêmeas desta espécie foram expostas a concentração de 0,5 mg de Al L-1 em pH neutro (Al N), 0,5 mg de Al L-1 em pH ácido (Al - Ác), somente em pH neutro (CTR N) e somente em pH ácido (CTR Ac) por 96h. Após o período de exposição aguda, os animais foram sacrificados e tecidos como encéfalo, brânquias, fígado, gônadas e músculo, foram retirados para a determinação da concentração de alumínio por espectrofotometria de absorção atômica. A hipófise foi coletada e congelada para a quantificação da expressão da subunidade β dos genes das gonadotropinas, FSH (hormônio folículo estimulante) e LH (hormônio luteinizante) por qRT-PCR. Os resultados mostraram que animais expostos ao alumínio, tanto em pH ácido quanto neutro, acumularam mais alumínio no encéfalo e no músculo esquelético em relação aos grupos controles. Nas brânquias, apenas quando os animais são expostos ao alumínio em pH neutro, acúmulos diferenciados são encontrados e, adicionalmente, fêmeas expostas ao pH ácido, independente da concentração do alumínio na água, acumulam mais metal nos filamentos branquiais. Nos ovários, tanto a presença de maiores concentrações deste metal na água, quanto a acidez da mesma foram determinantes na incorporação do alumínio. Os dados de expressão gênica evidenciam que, animais submetidos ao alumínio em pH 5,5 apresentaram uma redução na expressão do gene do FSH, no entanto em pH neutro esta alteração na expressão deste gene não foi encontrada. Os animais expostos ao alumínio, tanto em pH ácido quanto neutro apresentaram diminuição na expressão de LH. A análise dos resultados de expressão do LH combinada com o perfil dos progestágenos plasmáticos previamente conhecidos para os mesmos animais, mostram que, em condições adversas de pH (ácido) a ação do alumínio como um disruptor endócrino foi traduzida em alterações na fisiologia gonadal, limitando a produção do 17αOHP (hidroxiprogesterona), importante hormônio na ovulação. Por outro lado, quando as condições de pH foram favoráveis (neutro), a diminuição da expressão de LH não levou ao desajuste na produção de 17αOHP, ou seja, os animais de alguma forma, compensaram esta disfunção.Aluminum and acidic pH are known to be toxic to the ichthyofauna. The main goal of the present study was to evaluate the effects of aluminum and acidic pH in the reproductive physiology of Oreochromis niloticus. To conduct this experiment, females were exposed to aluminum at 0.5 mg of Al L-1 in neutral pH (Al N), 0.5 mg of Al L-1 in acidic pH (Al - Ac), a control group in neutral pH (CTR N) and acidic pH (CTR Ac) for 96h. After the acute exposition period, the animals were killed and the following tissues, brain, gills, liver, gonads and muscle, were frozen for aluminum determination by atomic absorption spectrophotometer. The pituitary was collected and also frozen to quantify the gene expression of the β subunit of the gonadotropins FSH (follicle stimulating hormone) and LH (luteinizing hormone) using qRT-PCR. The results showed that animals exposed to aluminum, even in acidic or neutral pH, accumulated more aluminum in brain and white muscle comparing with their control groups. In the gills, only when the animals were exposed to aluminum in neutral pH, different patterns of accumulation were found and, additionally, females exposed to acidic pH, independent of the water aluminum concentration, accumulated more metal in the gills filament. In the ovaries even the presence of higher aluminum concentration in water and the acidic pH were essential in aluminum deposition. The gene expression data showed that, animals exposed to aluminum in pH 5.5 reduce FSH gene expression, however in neutral pH this alteration was not observed. Animals exposed to aluminum, even in acidic or neutral pH, reduced LH expression. The data analyses of LH gene expression combined with the plasma progestagens, previously known for the same animals, showed that, in adverse pH conditions (acidic), the aluminum role as an endocrine disruptor was translated in alterations in gonad physiology, reducing the production of 17αOHP (hidroxy progesterone), an important hormone in ovulation. On the other hand, when the pH conditions were optimum (neutral), the reduced LH gene expression did not reflect in impairments in the 17αOHP production, which means the animals, somehow, compensated this dysfunction.
39
Madi, Rubens Riscala. "Utilização dos helmintos parasitos de Geophagus brasiliensis (Quoy & Gaimard, 1824) (Cichlidae; Perciformes) como indicadores ambientais." [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315269.
Full textAbstract:
Orientador: Marlene Tiduko UetaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-04T12:58:43Z (GMT). No. of bitstreams: 1 Madi_RubensRiscala_D.pdf: 9621964 bytes, checksum: 62171358c6dd9c0bf0ceb26ed12fd16c (MD5) Previous issue date: 2005
Resumo: Alguns parasitos de peixes podem ser utilizados como indicadores da qualidade e saúde ambiental. Por fazerem parte de uma complexa cadeia de relações os hospedeiros intermediários e paratênicos, geralmente pequenos e delicados, variam seus níveis populacionais conforme o tipo de poluente refletindo em alterações do parasitismo em peixes. A escolha de uma espécie de peixe como bio-indicador é fator fundamental para a correta utilização dessa ferramenta de análise ambienta!. Neste trabalho foram comparados os parasitismos do peixe Geophagus brasiliensis (Cichlidae, Perciformes) em dois reservatórios com diferentes níveis de influência antrópica e eutrofização. Foram verificados os helmintos parasitos cavitários, teciduais e de brânquias. Foram calculados os índices de diversidade de Simpson e de Shannon, o índice de uniformidade de HiII, os coeficientes de associação de Jaccard, de Dice e de Ochiai e as variações nas taxas de prevalência e intensidade média de infecção. Para o modelo adotado, os índices que melhor refletiram a influência do tipo de ambiente e as variações ocasionadas dentro destes ambientes foram a prevalência e a intensidade média de infecção. Os resultados obtidos com os índices de associação demonstraram a independência das relações entre os helmintos parasitos encontrados. Através dos cálculos das prevalências e intensidades médias de infecção os parasitos podem ser utilizados como indicadores de alterações ambientais (metacercárias de Clinostomum sp. e Ancyrocephalinae) e indicadores faunísticos em ambientes distintos (metacestódeos de Proteocephalidea e Cyclophyllidea e o nematódeo Procamallanus peraccuratus). Foram encontradas também larvas de Contracaecum sp. cujos resultados não foram suficientes para uma conclusão sobre o seu papel como indicador ambienta!
Abstract: Some parasites of fishes can be utilized as indicators of water quality and environmental health. As intermediate and paratenic hosts, generally small and delicate, belonging to a complex relationship chain, they must vary their population in accordance to the variety of pollutant, reflects in alteration of parasitism in fishes. The choice of the fish specie as bio-indicator is a essential factor to a correct utilization as toei of environmental analysis. In this work, it was compared the parasitism of Geophagus brasiliensis (Cichlidae, Perciformes) in two rese rvo i r with different levels os antropic influence and eutrophication. The cavities, tissular and gill helminths parasites were verified. The Simpson's and Shannon's diversity indices, the HiII's evenness index, the Jaccard's, Dice's and Ochiai's interespecific association indices and the variations in prevalence and mean intensity of infection were calculated. To the model adopted the indices that better reflected the influence of environmental type and the variations that occurred inside the environment were the prevalence and intensity of infection. The interespecific association indices demonstrate the independence of relations among the helminths parasites. Through the estimate of prevalence and mean intensity of infection indices, the parasites can be utilized as indicators of environmental changes (metacercariae of Clinostomum sp. and Ancyrocephalinae) and faunistics indicators of distincts environments (metacestodes of Proteocephalidea and Cyclophyllidea and the nematode Procamallanus peraccuratus). Larvae of Contracaecum sp. were also found, whose resulting were not sufficient to a conclusion about its function as environmental indicator
Doutorado
Parasitologia
Doutor em Parasitologia
40
Stefani, Patrícia Monte. "Ecologia trófica de espécies alóctones (Cichla cf. ocellaris e Plagioscion squamosissimus) e nativa (Geophagus brasiliensis) nos reservatórios do rio Tietê." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18139/tde-07022007-090755/.
Full textAbstract:
A introdução de espécies nos ecossistemas pode levar a conseqüências difíceis de serem controladas, sendo que a competição por recursos alimentares talvez seja o principal meio pelo qual uma espécie introduzida possa afetar as espécies nativas, podendo ocasionar a extinção. Neste sentido, os estudos de alimentação tornam-se importantes ao fornecerem subsídios para compreender o funcionamento trófico de um ecossistema. Considerando estes aspectos, o objetivo da pesquisa foi conhecer a ecologia trófica das espécies introduzidas (Plagioscion squamosissimus e Cichla cf. ocellaris) e da espécie nativa (Geophagus brasiliensis), avaliando as possíveis interações entre elas. Para o estudo da dieta das espécies escolhidas, foram utilizados os exemplares capturados durante o desenvolvimento do projeto PROBIO 2. As coletas foram realizadas nos seis reservatórios do Médio e Baixo rio Tietê, no período de novembro de 2002 a fevereiro de 2004. Foram realizadas análises quantitativas (freqüência de ocorrência, método volumétrico e método gravimétrico) dos itens encontrados, caracterizando a preferência alimentar das espécies. Neste trabalho o acará (Geophagus brasiliensis), apresentou um hábito alimentar onívoro, consumindo principalmente larvas de Diptera, insetos aquáticos e microcrustáceos. A espécie (Cichla cf. ocellaris) apresentou um hábito alimentar piscívoro, consumindo principalmente peixes e crustáceos. A corvina (P. squamossisimus) foi considerada piscívora, apresentando um amplo espectro alimentar, consumindo principalmente peixes, insetos aquáticos e crustáceos. A ampla distribuição da espécie P. squamosissimus nos seis reservatórios do médio e baixo rio Tietê e a plasticidade alimentar evidenciada pela análise de conteúdo estomacal sugerem que a corvina exerce uma forte pressão sobre as espécies nativas, cuja dinâmica populacional pode ser alterada.The species introduction into the ecosystems may lead to difficult consequences hard to be controlled and the competition for food resources being the main factor by which introduced species can affect the native species, even causing their extinction. In this sense, the feeding studies are important by supplying subsidies to understand the trophic functioning of an ecosystem. Considering these aspects, the objective of this research was to know the trophic ecology of the introduced species Plagioscion squamosissimus and Cichla cf. ocellaris and of the native species (Geophagus brasiliensis), evaluating the possible interactions between them. For the diet study of the chosen species, were used the samples collected during the development of the project PROBIO 2. Sampling was carried out in six reservoirs of the Middle and Low Tietê river, between November 2002 and February 2004. Qualitative analysis was done (occurrence frequency, volumetric method e gravimetric method) on the found items, characterizing the species feeding preference. In this work, the acará (Geophagus brasiliensis) presented an omnivorous feeding habit, mainly consuming Dipteral worms, aquatic insects and micro crustaceans. The species (Cichla cf. ocellaris) presented a piscivorous feeding habit, mainly consuming fishes and crustaceans. The curvina (P. squamossisimus) was considered piscivorous, presenting an ample feeding spectrum, mainly consuming fishes, aquatic insects and crustaceans. The ample distribution of the specie P. squamosissimus in the six reservoirs of the Middle and Low Tietê river and the plasticity revealed by the stomach content analysis, suggests that the curvina exercises a strong pressure over the native species, in which population dynamics can be changed.
41
Narcizo, Amanda de Moraes. "Efeitos in vitro do alumínio como desregulador endócrino sobre a hipófise e ovários de Oreochromis niloticus (Teleostei: Cichlidae)." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/41/41135/tde-02062014-141624/.
Full textAbstract:
O alumínio (Al) é o metal mais abundante na natureza e tornou-se importante poluente aquático trazendo prejuízos a reprodução de teleósteos, atuando como um desregulador endócrino. No entanto, em experimentos in vivo não é possível demonstrar que os efeitos do Al no eixo endócrino reprodutivo são devido a sua atuação direta sobre os órgãos que o compõem. Por isso, este trabalho teve como objetivo avaliar o efeito direto do Al sobre células foliculares ovarianas, gonadotrópicas e somatolactínicas hipofisárias de fêmeas maduras de Oreochromis niloticus. Para isso dois experimentos in vitro de exposição ao Al foram realizados: um utilizando-se ovários maduros e outro hipófises de fêmeas sexualmente maduras. Para os experimentos ovarianos, frações de ovários maduros foram incubadas por 4 horas formando os seguintes grupos: 1) Grupo controle (Ctr): tecido ovariano exposto somente à solução de Krebs-Ringer-glucose-HEPES; 2) Grupo gonadotropina coriônica humana (hCG): tecido exposto à 6 µg/ml de hCG (Ovidrel); 3) Grupo (hCG+Al): tecido exposto à 6 µg/ml de hCG (Ovidrel) + cloreto de alumínio (AlCl3) - 10mM; 4) Grupo (Al): exposto somente ao AlCl3 - 10mM. A concentração dos hormônios 17β-estradiol (E2) e 17α-hidroxiprogesterona (17αOHP) no meio de incubação foi determinada por ELISA. Para os experimentos hipofisários, hipófises de fêmeas sexualmente maduras foram incubadas por 24 horas formando os seguintes grupos: 1) Ctr: hipófise exposta somente ao meio L15 (controle interno); 2) GnRH: hipófise exposta somente ao GnRH (controle de liberação de gonadotropinas); 3) GnRH+Al: hipófise exposta ao GnRH + AlCl3 10mM e 4) Al: hipófise exposta somente AlCl3 10mM. Após o período experimental, foram realizadas análises de qPCR (PCR quantitativo), análises de imunohistoquímica, e de microscopia eletrônica. Os resultados do experimento ovariano mostraram que os fragmentos ovarianos do grupo exposto à hCG apresentaram um aumento significativo da liberação dos hormônios E2 e 17αOHP em relação aos demais grupos, confirmando o efeito desta gonadotropina sintética na liberação destes esteroides gonadais. No entanto, a administração conjunta da hCG com Al (hCG+Al) não gerou este aumento da produção dos esteroides em relação ao grupo controle. Estes dados evidenciam que o Al inibiu a resposta celular das células esteroidogênicas ovarianas às gonadotropinas. Os resultados dos experimentos hipofisários mostraram que o Al (GnRH+Al e Al) afetou a expressão gênica dos genes estudados (βFSH, (βLH, SL) inclusive dos normalizadores (EF1α e (βAc), o que tem sido comum em experimentos de ecotoxicologia. Os dados de microscopia eletrônica mostraram desestruturação celular nas hipófises que foram expostas ao Al e as análises de imunohistoquímica apontaram que o Al (GnRH+Al e Al) não interferiu sobre a quantidade de grânulos de βLH e SL, enquanto o grupo Al indicou uma diminuição na quantidade de grânulos de βFSH, sugerindo que o Al afeta a dinâmica de síntese/liberação desta gonadotropina. Estes dados evidenciam a toxicidade do Al diretamente sobre ambos os órgãos estudados, tanto em nível de resposta celular quanto em nível estrutural confirmando o potencial do Al como um DE e amplia as perspectivas de estudo sobre o mecanismo de ação do Al como um DEAluminum (Al) is the most abundant metal in nature and has become an important water pollutant impairing reproduction of teleosts, acting as an endocrine disrupter. However, in vivo experiments cannot demonstrate that the effects of Al on the reproductive endocrine axis are due to direct action on the organs that compose it. Therefore, this study aimed to assess the direct effect of Al on ovarian follicular cells, gonadotropic and somatolactin pituitary cells of mature females of O. niloticus. For this, two in vitro exposure experiments of Al were performed: one using mature ovaries and other using pituitaries of sexually mature females. For ovarian experiments, fractions of mature ovaries were incubated for 4 hours to obtain the following groups: 1) control group (Ctr): ovarian tissue only exposed to Krebs- Ringer-HEPES-glucose; 2) human chorionic gonadotropin (hCG) group: tissue exposed to 6 mg/ml hCG (Ovidrel); 3) hCG + Al group: tissue exposed to 6 mg/ml hCG (Ovidrel) + aluminum chloride (AlCl3) - 10mM; 4) Al group: only exposed to 10 mM AlCl3. The concentration of the hormones 17β-estradiol (E2) and 17α-hydroxyprogesterone (17αOHP) in the incubation medium was determined by ELISA. For pituitary experiments, pituitaries of sexually mature females were incubated for 24 hours to form the following groups: 1) Ctr: pituitary exposed only to L15 (internal control); 2) GnRH: only exposed to the pituitary GnRH (gonadotropin releasing hormone); 3) GnRH + Al: exposed to the pituitary GnRH AlCl3 + 10 mM and 4) Al: 10mM AlCl3 only exposed pituitary. After the assay period, analysis of qPCR (quantitative PCR), analysis of immunohistochemistry and electron microscopy were performed. The results of the experiment showed that the ovarian exposed to hCG group showed a significant increase in the release of E2 and 17αOHP compared to the other groups, confirming the effect of synthetic gonadotropin in the release of these gonadal steroids. However, the administration combined of hCG with Al (Al + hCG) did not generate this increased production of steroids compared with the control group. These data show that Al inhibited the cellular response of the ovarian steroidogenic cells to gonadotropins. The results of the experiments with pituitaries showed that Al (GnRH + Al and Al) affected the gene expression of the genes studied (βFSH, (βLH, SL) including the house keeping genes (EF1α and βAc), what has been common in ecotoxicology experiments. Data from electron microscopy showed cell disruption in the pituitary glands that were exposed to Al and immunohistochemical analyzes showed that Al (GnRH + Al and Al) did not affect the amount of granules of βLH and SL, while the Al group indicated a decrease the amount of βFSH granules, suggesting that Al affects the dynamics of the synthesis/release of this gonadotropin. These data show the toxicity of Al directly on both organs studied, at both the cellular response as for structural level confirming the potential of Al as a DE and increases the perspectives of study on the mechanism of action of Al as a DE
42
Barroco, Lorenzo Soriano Antonaccio. "Taxa de mortalidade relacionada à prática da pesca esportiva do cichla spp. na região do médio Rio Negro, Amazonas, Brasil." Universidade Federal do Amazonas, 2013. http://tede.ufam.edu.br/handle/tede/2746.
Full textAbstract:
Made available in DSpace on 2015-04-11T13:56:28Z (GMT). No. of bitstreams: 1
Lorenzo Barroco.pdf: 722257 bytes, checksum: 356df29a6c95a7e03f6ab0ca96899495 (MD5)
Previous issue date: 2013-05-29Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The expansion of recreational fishing in Brazil started in the 1990 s, when more and more people came to the Amazon in search of peacock bass (Cichla spp.). The behavior of this cichlid, which attacks lures, is especially exciting for anglers. The middle Negro River has become one of the most popular areas of sport fishing of the world, where the largest peacock bass can be found. The importance of catch-and-release fishing as an sustainable fishing strategy has been shown to directly help conserve peacock bass fish stocks in the region. In this study, peacock bass mortality was evaluated in relation to catch-and-release fishing, comparing two types of artificial lures: the jig and a traditional middle-water type. Fish, samples were collected in January/February and October/November of 2012 in the Unini River, a right margin tributary of the Negro River, in the municipal region of Barcelos in Amazonas State. A total of 191 peacock bass were caught, 90 by jig lure and the rest by the middle-water lure. Both fish groups were submitted to experimental confinement during a period of three days. In both groups, 30 fish were confined individually and 60 confined collectively. Additionally, 11 fish from the second group had radio transmitters attached to be used in telemetry. The mortality rate was calculated for each type of lure and type of confinement. No mortality was encountered for the group caught with a jig beat lure. In comparison, the middle-water lure showed a mortality rate of 1.66% for the collective confinement and 18.18% for the monitoring involving telemetry. For both types of lures, no mortality was observed for fish confined individually. The data was plotted using a Kruskal-Wallis variance analysis that showed values of X2 (1.179) = 0,502 and p= 0,478 for confined environments. The same test show values of X2 (1.179) = 1,005 e p= 0,316 for the different lures. The results indicated that neither confinement type or lure type had a significantly negative impact on the peacock bass mortality rate from the catch-and-release fishery, demonstrating that catchand- release fishing has a very small impact on peacock bass mortality. Therefore, this type of recreational fishing is beneficial as a strategy to help conserve peacock bass fish stocksfishery
A expansão da pesca amadora no Brasil teve inicio na década de 90 e tem alcançado os rios de água preta na região Amazônica, principalmente no médio Rio Negro onde são encontrados os grandes tucunarés (Cichla spp.). Com o acentuado crescimento desta atividade na região, a prática do pesque-solte vem sendo proposta como um procedimento sustentável na pesca esportiva dos tucunarés da região. Contudo, em face das dúvidas acerca da eficácia desta modalidade de pesca, avaliamos o efeito do pesque-solte sobre a sobrevivência do tucunaré, comparando dois tipos de iscas artificiais o jig e a meia-água. Foram realizados dois ensaios nos períodos de janeiro/fevereiro e outubro/novembro de 2012 no rio Unini, afluente da margem direita do rio Negro (Barcelos-AM). Em total foram capturados 191 tucunarés: 90 por iscas jig e os demais por iscas de meiaágua. Ambos os grupos de peixes foram submetidos a experimentos de confinamento por um período de 3 dias. Do primeiro grupo, 30 peixes foram confinados individualmente e 60 coletivamente. No segundo grupo, 30 foram confinados individualmente e 60 coletivamente. Adicionalmente, 11 peixes deste grupo foram marcados com transmissores de rádio para monitoramento por telemetria. A taxa de mortalidade foi calculada através do percentual dos indivíduos mortos para cada tipo de isca e ambiente de confinamento. Não houve mortalidade para o grupo de tucunaré capturado com jig. Por outro lado, a isca de meia-água apresentou taxa de mortalidade de 1,66% para o confinamento coletivo e de 18,18% para os monitorados por telemetria, não havendo, portanto mortes de indivíduos confinados individualmente. Estes dados foram analisados por meio de uma análise de variância Kruskal-Wallis, onde apresentaram valores de X2 (1.179) = 0,502 e p= 0,478 para os ambientes de confinamentos. O mesmo teste apresentou valores de X2 (1.179) = 1,005 e p= 0,316 para as iscas utilizadas. Dessa forma, os resultados indicam que ambos, o tipo de ambiente e o tipo de isca, não apresentaram influencia significativa sobre a taxa de mortalidade dos tucunarés na prática do pesque-solte. Estes resultados mostram que a prática desta modalidade de pesca amadora, resulta em baixa taxa de mortalidade para os tucunarés. Sendo assim o pesque-solte se mostra uma atividade que não prejudica a sustentabilidade dos estoques pesqueiros de tucunaré. Palavras-chave: Pesque-solte; tucunaré; pesca amadora; mortalidade de peixes
43
Hsieh, Chia-Yu, and 謝嘉裕. "Study on Francisellosis in Cichlid Fish." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/66296498017790503079.
Full textAbstract:
博士國立屏東科技大學
獸醫學系
95
Over the course of the past 14 years, an unrecognized intracellular organism has emerged from fresh- and brackish- cultured diseased tilapia and causing high mortality, up to 95% in some cases in Taiwan. The causative agent is a cocco-bacillus with a polymorphous shape, and can be cultured in Chinook salmon embryo cell line (CHSE-241) and Tilapia ovary (TO-2) cells, but does not grow on artificial synthetic media, which was named rickettsia-like organism (RLO) or tilapia intracellular organism (TIO). Therefore, many researchers suggest it is an obligate intracellular bacterium, such as Piscirickettsia salmonis. Based on electron microscopic examination, the sequences of the 16S rRNA gene and phylogenetic analysis, RLO/TIO was a unique Francisella-like bacterium that was most closely related to Francisella spp. The intracellular organism associated with granulomas in tilapias might represent an undescribed Francisella species. The general context of this thesis is formal methods for characterization and identification of a novel bacterial microorganism, commonly referred to as Francisella-like bacterium (FLB), induced systemic granulomas in tilapias. It is weakly Gram-negative and polymorphic, and can be cultured in Chinook salmon embryo cell line (CHSE-214). The thesis is be roughly divided into three major parts. The first is dedicated to present the PCR assays for 16S rRNA gene sequence analysis, electronmicroscopical examination and phenotypic characteristics for ten isolated strains of Francisella-like bacterium from the visceral granulomas of diseased tilapia in Taiwan. FLB colonies developed slowly, requiring 3 to 6 days incubation at 23℃ on the Thayer-Martin agar. Smooth colonies with a grayish pigment were observed. They showed little or no growth at 30℃ and none at 35℃. All the isolates only grow on Thyer-Martin agar. The organisms were strict aerobes, non-motile, and had negative reactions for reduction of nitrate, beta-galactosidase and resazurin, and hydrolysis of glucoside, ONPG, L-arabinoside, leucine and glycine. They were weakly positive for catalase, but strongly positive for β-lactamase, proline and sucrose. Compared the nucleotide sequences of the whole 16S rRNA gene, they had high sequence identities to F. philomiragia (98.7%), F. tularensis subsp. novicida (97.4%) and F. tularensis subsp. tularensis (96.2%), respectively. They might belong to Francisella species. In additional, we were confirmed by the in situ hybridization technique. The second part is to distinguish the FLB strains at the genus, species and subspecies levels using PCR assays that were applied using the universal primer, Francisella genus-specific primers and FLB-specific primers. These results allowed sensitive identification of FLB as a new species of the genus Francisella and could discriminate it from Francisella tularensis, F. novicida and F. philomiragia. The third part is to distinguish to archived formalin-fixed, paraffin-embedded tissues from diseased ornamental fish associated with visceral granulomas that were examined by histopathology, polymerase chain reaction (PCR) and in situ hybridization (ISH) for detection of Francisella-like bacterium (FLB). ISH was more sensitive than PCR or routine histopathological examination, based on the examination of archived formalin-fixed, paraffin-embedded tissues in this study. Keyword: Cichlid Fish, Francisella-like bacterium (FLB), Rickettsia-like organism (RLO), polymerase chain reaction (PCR), in situ hybridization (ISH)
44
Félix, Ana Sofia Mendes da Silva Santos. "Neuroendocrine regulation of social Interactions in a cichlid fish." Doctoral thesis, 2019. http://hdl.handle.net/10400.12/7475.
Full textAbstract:
Tese apresentada para cumprimentos dos requisitos necessários à obtenção do grau de Doutor em Biologia do Comportamento apresentada no ISPA - Instituto Universitário no ano de 2019.O estudo do comportamento animal e em particular do comportamento social tem atraído investigadores desde há muito tempo. Todos os animais interagem com os outros, característica fundamental para a sua sobrevivência e reprodução. No entanto, para obter uma total compreensão do comportamento social, é necessária a integração de seus vários componentes. Com esta tese, pretendemos clarificar este tópico, estudando como o cérebro controla o comportamento através da ação conjunta de seus circuitos neurais, genes e moléculas, e também como o ambiente social de forma recíproca influencia o cérebro. Baseado neste objetivo e usando a tilápia de Moçambique (Oreochromis mossambicus) como espécie modelo, num primeiro estudo investigámos como o comportamento social é controlado por uma rede dinâmica de regiões cerebrais, a Social Decision Making Network (SDMN). Aqui, tentámos entender quais são as pistas específicas que desencadeiam mudanças no padrão de ativação dessa rede neural, usando lutas entre machos. Os nossos resultados sugerem que é a avaliação mútua do comportamento de combate que impulsiona mudanças temporárias no estado do SDMN, e não a avaliação do resultado da luta ou apenas a expressão de comportamento agressivo. Em seguida, explorámos a modulação hormonal do comportamento social, em particular pelo neuropeptídeo vasotocina. Para isso, manipulámos o sistema da vasotocina injetando vasotocina e um antagonista específico dos receptores de vasotocina V1A em machos. Para distinguir se a vasotocina afeta o comportamento isoladamente ou em combinação com andrógenios, conduzimos esta experiência em peixes castrados e peixes controlo. Curiosamente, descobrimos que a vasotocina afetou o comportamento dos machos em relação às fêmeas, mas não em relação aos machos, e que os andrógenios e a vasotocina modularam a agressividade dos machos em relação às fêmeas. Em seguida, procurámos compreender como as interações sociais afetam os sistemas neuroendócrinos. Nesse sentido, utilizámos um paradigma de intrusões territoriais para avaliar os padrões temporais dos níveis de andrógenios e tentámos relacioná-los ao fenótipo comportamental de cada indivíduo. Obtivemos padrões distintos de resposta androgénica às interações sociais devido a diferenças individuais subjacentes em sua extensão de resposta. Este estudo oferece uma importante contribuição para a área de investigação, fornecendo possíveis razões para as discrepâncias associadas à hipótese de desafio, o principal modelo em endocrinologia comportamental que descreve a relação entre andrógenios e interações sociais. Finalmente, pensa-se que os andrógenios respondem às interações sociais como forma de preparar os indivíduos para outras interações. Assim, tentámos descobrir como um aumento de andrógenios no sangue afeta o cérebro. Para esse efeito, injetámos peixes com andrógenios e estudámos as mudanças transcriptómicas que ocorrem no cérebro usando a técnica de RNAseq, permitindo uma compreensão mais detalhada do efeito dos andrógenios no cérebro. Em suma, o comportamento social é complexo e depende de vários fatores internos e externos. Os resultados desta tese fornecem um contributo significativo para pesquisas futuras.
The study of animal behavior and in specific of social behavior has attracted researchers for a long time. All animals interact with others, a feature which is fundamental to their survival and reproduction. However, to get a complete understanding of social behavior, the integration of its various components is required. In this thesis, we aimed to shed light on this topic, studying how the brain controls behavior through the concerted action of its neural circuits, genes and molecules, and also how the social environment feedbacks and impacts the brain. Grounded upon this objective and using the Mozambique tilapia (Oreochromis mossambicus) as a model species, in a first study we investigated how social behavior is controlled by a dynamic network of brain regions, the Social Decision Making Network (SDMN). Here, we tried to understand what are the specific cues that trigger changes in the pattern of activation of this neural network, by using staged fights between males. Our results suggest that it is the mutual assessment of relative fighting behavior that drives acute changes in the state of the SDMN, and not the assessment of fight outcome or just the expression of aggressive behavior. Then, we explored the hormonal modulation of social behavior, in particular of the neuropeptide vasopressin. For this purpose, we manipulated the vasotocin system by injecting vasotocin and a specific antagonist of vasotocin receptors V1A in males. To distinguish if vasotocin affected behavior alone or in combination with androgens, we conducted this experiment in both castrated and control fish. Interestingly, we found that vasotocin affected the behavior of males towards females but not towards males and that both androgens and vasotocin modulated aggressiveness towards females. Next, we sought to comprehend how social interactions affect neuroendocrine systems. In that sense, we used a paradigm of territorial intrusions to assess temporal patterns of androgen levels and tried to relate them to the behavioral phenotype of each individual. We obtained distinct patterns of androgen response to social interactions due to underlying individual differences in their scope for response. This study makes an important contribution to the field by providing possible reasons for discrepancies associated with the Challenge Hypothesis, the major framework in behavioral endocrinology which describes the relationship between androgens and social interactions. Finally, it is believed that androgens respond to social interactions as a way to prepare individuals for further interactions. Thus, we tried to uncover how an androgen surge in the blood affects the brain. To accomplish this, we injected fish with androgens and studied brain transcriptomic changes with the RNAseq technique, allowing the achievement of a thorough understanding of the effect of androgens on the brain. In sum, social behavior is complex and dependent on several internal and external factors. The findings from this thesis provide significant insights for future research.
Fundação para a Ciência e Tecnologia
45
Teles, Magda. "Adult neurogenesis in a new model specie, the cichlid fish Oreochromis mossambicus." Master's thesis, 2010. http://hdl.handle.net/10400.12/4045.
Full textAbstract:
Dissertação de Mestrado apresentada ao ISPA - Instituto UniversitárioEm comparação com outros vertebrados, os peixes teleósteos têm um enorme potencial para produzir células novas no cérebro de animais adultos. Em contraste com os mamíferos, onde o processo de neurogénese adulta encontra-se restrito a duas áreas cerebrais, a zona subventricular (SVZ) e a zona subgranular parte do giro dentado do hipocampo, em peixes teleósteos foram descritas mais de 10 regiões neurogénicas. Através da marcação de células mitóticas com 5-bromo-2’-deoxiuridina (BrdU), foram caracterizadas as zonas proliferativas da Tilapia de Moçambique (Oreochromis mossanbicus). Nesta espécies, foram encontradas zonas proliferativas em regiões específicas do bolbos olfactivo, telecéfalo, região pré-optica, hipotálamo, tálamo, tecto óptico, torus longitudinalis, nas três divisões do cerebelo, valvula cerebelli, corpus cerebelli, e lobus caudalis e na região da medula, abrangendo assim toda a extensão cerebral. A localização destas zonas proliferativas parece ser extremamente conservada ao longo da taxonomia e até o número total de células produzidas parece ser mantido com pouca variação. Com um tempo de sobrevivência de 2 horas, foram encontrados na tilapia um total de 80.000 células novas em comparação com as 100.000 descritas para o peixe eléctrico Apteronotus leptorhynchus. Os nossos resultados sugerem que a actividade mitótica em regiões discretas do cérebro adulto são uma característica primitiva que tem sido conservada ao longo da evolução.
ABSTRACT: Compared to other vertebrate species, fish exhibit an enormous potential to produce new cells in the adult brain. In contrast to mammals, where proliferation zones are restricted to two brain areas, the sub ventricular zone (SVZ), and the subgranular zone (SGZ), part of the dentate gyrus of hippocampus, in teleost species more than 10 neurogenic regions have been described. By labeling mitotically dividing cells with 5-bromo-2'-deoxyuridine (BrdU), we have characterized the proliferation zones in the Mozambique tilapia (Oreochromis mossambicus). Proliferation zones were located in specific brain regions of the olfactory bulb, telencephalon, preoptic area, hypothalamus, thalamus, optic tectum, torus longitudinalis, in all three subdivisions of the cerebellum, the valvula cerebelli, the corpus cerebelli, and the lobus caudalis cerebelli and in the region of the medulla oblongata. These proliferation zones appeared to be extremely conserved across taxonomy and even the total number of new generated cells seems to be preserved. After 2 hours survival time we found a total of approximately 80.000 new cells for tilapia compared to 100.000 new cells described for Apteronotus leptorhynchus. Our results suggest that the presence of mitotic activity in specific brain regions is a primitive feature that has been conserved through evolution.
46
Whitaker, Keith William. "Plasticity in the startle-escape response of the African cichlid fish, Astatotilapia burtoni." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-12-4541.
Full textAbstract:
Ecological context, sensory inputs, and the internal physiological state are integrated for an animal to make appropriate behavioral decisions. However, these factors have rarely been studied in the same system. In the African cichlid fish Astatotilapia burtoni, males alternate between four phenotypes. Two are determined by social status and two are identified by the principle body coloration (yellow or blue). When socially dominant (DOM), fish display bright body coloration and a wealth of aggressive and reproductive behaviors. Subordinate (SUB) males decrease predation risk by adopting cryptic coloration and schooling behavior. Yellow males are more conspicuous than blue males, and DOMs and more conspicuous than SUBs, which means that yellow DOMs are most likely to be seen by predators. We therefore hypothesized that DOMs, yellow DOMs in particular, would show enhanced startle-escape responsiveness to compensate for their increased predation risk.
Indeed, behavioral responses to sound clicks of various intensities showed a significantly higher mean startle rate in DOMs than SUBs. When testing the same males after social change, yellow DOMs respond at a higher rate than yellow SUBs but blue males do not show plasticity. Electrophysiological recordings from the Mauthner cells (Mcells), the neurons triggering startle, were performed in anesthetized animals and showed larger synaptic responses to sound clicks in DOMs, consistent with the behavioral results. In addition, the inhibitory drive mediated by interneurons presynaptic to the M-cell was significantly reduced in DOMs. Using behavioral tests, intracellular recordings, and single-cell molecular analysis, immunohistochemistry and in-situ hybridization, I show here that serotonin modulates this socially regulated plasticity via the 5-HT receptor subtype 2 (HTR2A). Specifically, SUBs display increased sensitivity to pharmacological blockade of HTR2A compared with DOMs in both startle-escape behavior and electrophysiological properties of the M-cell. These receptors, however, are not expressed in the Mauthner neurons, but in the inhibitory interneurons that regulate the Mcell’s membrane properties.
I show a role for 5-HT in modulating startle plasticity and increase our understanding of the neural basis of behavioral plasticity. More broadly, this study provides an integrative explanation of an ecological and social trade-off at the level of an identifiable decision-making neural circuit.text
47
Bockelman, Angela Kay. "Courtship and parental care in the biparental convict cichlid fish (Archocentrus nigrofasciatus) : a test of their relationship /." Diss., 2004. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3127518.
Full text
48
DEDDEN, ILSE. "The effect of gonadotropin releasing hormone on opsin gene expression and spectral sensitivity in zebra cichlid fish (Metriaclima zebra)." Thesis, 2011. http://hdl.handle.net/1974/6264.
Full textAbstract:
Sexual selection and the maintenance of species diversity in Lake Malawi cichlid fishes are greatly dependent on optical communication, which is influenced by environmental, physiological and endocrinological factors. The diversity in spectral sensitivity of cichlids has been partially attributed to differences in opsin gene expression, with each species preferentially expressing a subset of seven possible genes. Hormones such as gonadotropin releasing hormone (GnRH) can mediate changes in gene expression and the presence of GnRH immunoreactive fibers and GnRH receptors throughout the retinal layers make it an excellent candidate for mediating changes in visual processes. Effects of exogenous GnRH administration on the visual system of zebra cichlids (Metriaclima zebra) via prolonged release cholesterol implants and intubation was investigated using electroretinogram (ERG) recordings, quantitative real-time RT-PCR and in situ hybridization. Three week and ten week sampling periods were used in the intubation study. No obvious differences in spectral sensitivity were evident when looking at a-wave, b-wave and d-wave components of the ERG waveform in any of the treatment groups. A multiple mechanism model was used to describe the cone mechanisms mediating spectral sensitivity and this analysis showed that the activity of cones was shaped by opponent and non opponent cone interactions based on subsets of five opsin genes previously described in cichlids (SWS1, SWS2b, RH2b, RH2aβ, and RH2aα). Although differences in the spectral sensitivity between control and GnRH-treated fish were not evident on a functional level, there were changes in the gonadosomatic index in the intubation group. Quantitative real-time RT-PCR (qRT-PCR) and in situ hybridization demonstrated that treatment with a synthetic GnRH3 analogue using the oral intubation delivery system resulted in statistically significant changes in opsin gene expression in both three week and ten week treatment groups, specifically the upregulation of RH2b and the downregulation of RH2a opsin genes. Moreover, in situ hybridization analysis showed that the pattern of labeling for the RH2a and RH2b riboprobes corroborated the changes in opsin gene expression found in the qRT-PCR data. In contrast, GnRH treatment using the cholesterol implant delivery system did not result in significant changes in spectral sensitivity or opsin gene expression.Thesis (Master, Biology) -- Queen's University, 2011-01-05 22:57:11.308
49
Yeh, Shang-wei, and 葉上暐. "Neural marker expression of a clonal cell line (ARB8-2) isolated from the brain of cichlid fish (Aequidens rivulatus)." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/18377282290998947276.
Full textAbstract:
碩士國立高雄大學
生命科學系碩士班
102
A clonal cell line (ARB8-2) isolated from the brain of cichlid fish (Aequidens rivulatus) was investigated by reverse transcription polymerase chain reaction (RT-PCR),Western blot, immunocytochemistry, PCR and Real-time PCR were utilized to characterize the molecular expression of ARB8-2 cell line. The results showed that the ARB8-2 express radial glia markers such as nestin and brain lipid binding protein (BLBP), astrocyte markers such as glial fibrillary acidic protein (GFAP), glutamine synthetase (GS) and vimentin, oligodendrocyte progenitor cell marker such as A2B5, neuron markers such as tyrosine hydroxylase (TH), epithelial cell markers such as gap junction connexin 43 (Cx43) and tight junction occludin, melanocyte markers such as tyrosinase, tyrosinase-related protein-2 (TRP-2), microphthalmia-associated transcription factor (MITF), SLC45A2 and keratinocyte-associated transmembrane protein 2 (KCT-2) and retinal epithelial marker retinal pigment epithelium-specific 65 (RPE65). However, the ARB8-2 also express homeodomain-containing transcription factors NKX 2.3 and NKX 6.2 and GATA 3. The results indicated that ARB8-2 might be the neural stem cell.
50
Coetzee, Lizet. "Bioaccumulation of metals in selected fish species and the effect of ph on aluminium toxicity in a cichlid oreochromis mossambicus." Thesis, 2012. http://hdl.handle.net/10210/6562.
Full textAbstract:
M.Sc.The upper catchment of the Olifants River, from its origin near Bethal, to its confluence with the Wilge River, north of Witbank, as well as it tributaries, are being subjected to increasing afforestation, mining, power generation, irrigation, domestic and industrial activities. These activities have a profound effect on the water quality and the major point sources of pollution in this area include mines, industries and very importantly, combined sewage purification works, located alongside the river, which, in addition to oxidizable material contains detergents, nutrients, and metals. It was therefore necessary to determine the extent to which these activities affect the water quality of the system. The impact of these activities was therefore addressed by a Water Research Commision Project namely "Lethal and sublethal effects of metals on the physiology of fish" of which the present study investigated effects at two localities, namely in the Olifants River (locality OR1) before its confluence with the Klein Olifants River and a locality in the Klein Olifants River (locality KOR1). Apart from the field study, toxicity tests were also performed in a laboratory, in order to determine the effects of low pH and elevated aluminium concentrations on the haematology, osmoregulation and carbohydrate metabolism of the Mozambique Tilapia, Oreochromis mossambicus as the acidification of soil systems may cause the transfer of aluminium into aqueous solutions, where it may be present in different forms. During the field study, the chemical and physical characteristics of the river water were evaluated, with special attention to the concentrations of certain metals (manganese, copper, chromium, lead, nickel, zinc, iron and aluminium) in the water and sediment, as well as in fish, which are known to accumulate the elements supra and are therefore valuable as indicators of these pollutants. The two fish species used for the investigations were the African sharptooth catfish, Clarias gariepinus and the moggel, Labeo umbratus. Four tissue types were dissected, namely the muscle, liver, skin and gill tissues. The metal concentrations in these organs/tissues, as well as in the water and sediment, were determined in a laboratory with an atomic absorption spectrophotometer. Statistical analyses were performed on the results obtained from this study and the order and extent of bioaccumulation of these metals in the water and sediment were determined, as well as in the fish organs/tissues. Its dependence on the size, sex and species of the fish and the localities and seasons were investigated.