To see the other types of publications on this topic, follow the link: Parasite morphology.
Journal articles on the topic 'Parasite morphology'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Parasite morphology.'
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 journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Rahimian, Hassan. "Parasites of fingerling herringClupea harengusL.: ecology and fine morphology." Journal of Helminthology 81, no. 2 (2007): 199–217. http://dx.doi.org/10.1017/s0022149x07735381.
Full textAbstract:
AbstractThe parasite fauna of young-of-the-year herringClupea harengusL., off Gullmarsfjord and Brofjorden, west coast of Sweden, was studied between May and October for 4 years, from 1994 to 1997. Fifteen species of parasites were found: two Protozoa –Trichodina sp.andCeratomyxa auerbachi; one species of uncertain affinity –Ichthyophonus hoferi; two Monogenea –Gyrodactylus harengiandPseudanthocotyloides heterocotyle; five Digenea –Cryptocotyle linguametacercariae,Cercaria pythionikemetacercariae,Hemiurus luehei,Lecithaster confususandPseudobacciger harengulae; three Cestoda plerocercoids –Bothriocephalussp., an acrobothriid and a tetraphyllid; one Nematoda –Hysterothylacium aduncumlarva; and one Copepoda –Caligus elongatus. The number of species found in this study represents more than one-sixth of all parasites reported in herring worldwide and all parasites were acquired locally. The parasite fauna of herring from the west coast of Sweden is compared with that of herring from the Baltic Sea and other areas of the north-east Atlantic. The prevalence and intensity of parasites are presented and discussed. Morphological descriptions are based on both light and scanning electron microscopy and new features are described. Possible applications of this new information about the parasite fauna, in different areas of fisheries and fish biology studies, are discussed.
2
GRUBER, JANINE, PETRA GANAS, and MICHAEL HESS. "Long-term in vitro cultivation of Histomonas meleagridis coincides with the dominance of a very distinct phenotype of the parasite exhibiting increased tenacity and improved cell yields." Parasitology 144, no. 9 (2017): 1253–63. http://dx.doi.org/10.1017/s0031182017000646.
Full textAbstract:
SUMMARYThe majority of research on Histomonas meleagridis was performed in the first half of the last century, especially those on morphological aspects. In the present study identical monoxenic settings for cultures of the same H. meleagridis clonal strain in its virulent low passage and attenuated high passage form enabled a comparative analysis of parasite characteristics. For the first time, it could be shown that long-term in vitro cultivation led to a severe shift in cell morphology, with the occurrence of a very distinct phenotype expressing a flagellated and highly amoebic cell morphology. Furthermore, the attenuated parasites showed better growth rates and a higher tenacity when confronted with adverse conditions. During these experiments up to 100% of the parasites, both virulent and attenuated, assumed a completely rounded morphology elucidated by electron microscopy. The findings indicate that such previously reported cyst-like stages are a defence strategy of H. meleagridis, independent of the passage level in vitro and pathogenicity in vivo. In conclusion, long-term in vitro passaging of H. meleagridis led not only to an attenuation of the parasite, as previously demonstrated, but also to a shift in the parasite's phenotype regarding morphology, growth behaviour and a higher level of tenacity.
3
PERKINS, S. L., E. S. MARTINSEN, and B. G. FALK. "Do molecules matter more than morphology? Promises and pitfalls in parasites." Parasitology 138, no. 13 (2011): 1664–74. http://dx.doi.org/10.1017/s0031182011000679.
Full textAbstract:
SUMMARYSystematics involves resolving both the taxonomy and phylogenetic placement of organisms. We review the advantages and disadvantages of the two kinds of information commonly used for such inferences – morphological and molecular data – as applied to the systematics of metazoan parasites generally, with special attention to the malaria parasites. The problems that potentially confound the use of morphology in parasites include challenges to consistent specimen preservation, plasticity of features depending on hosts or other environmental factors, and morphological convergence. Molecular characters such as DNA sequences present an alternative data source and are particularly useful when not all the parasite's life stages are present or when parasitaemia is low. Nonetheless, molecular data can bring challenges that include troublesome DNA isolation, paralogous gene copies, difficulty in developing molecular markers, and preferential amplification in mixed species infections. Given the differential benefits and shortcomings of both molecular and morphological characters, both should be implemented in parasite taxonomy and phylogenetics.
4
Öktener, Ahmet. "Morphology of Lernanthropinus trachuri ()(Copepoda, Siphonostomatoida, Lernanthropidae) from Bandirma Bay(Turkey)." Transylvanian Review of Systematical and Ecological Research 20, no. 3 (2018): 57–66. http://dx.doi.org/10.2478/trser-2018-0019.
Full textAbstract:
Abstract The parasitic copepod, Lernanthropinus trachuri (Brian, 1903) (Copepoda, Siphonostomatoida, Lernanthropidae)was found on the Mediterranean horse mackerel, Trachurus mediterraneus in Bandırma Bay, Turkey. The aim of this study is to present female Lernanthropinus trachuri with morphological characters with photos from Turkey. The details unseen in photos were supported with drawings. All parasites were firmly attached to the gill filaments of the host. This parasite is also specific for the genus Trachurus (Costa et al 2017). Therefore, this parasite may use as biomonitor or tag species for fish stock studies in Turkey.
5
Sweet, Andrew D., Sarah E. Bush, Daniel R. Gustafsson, et al. "Host and parasite morphology influence congruence between host and parasite phylogenies." International Journal for Parasitology 48, no. 8 (2018): 641–48. http://dx.doi.org/10.1016/j.ijpara.2018.01.007.
Full text
6
Coppens, Isabelle. "Metamorphoses of malaria: the role of autophagy in parasite differentiation." Essays in Biochemistry 51 (October 24, 2011): 127–36. http://dx.doi.org/10.1042/bse0510127.
Full textAbstract:
Several protozoan parasites undergo a complex life cycle that alternates between an invertebrate vector and a vertebrate host. Adaptations to these different environments by the parasites are achieved by drastic changes in their morphology and metabolism. The malaria parasites must be transmitted to a mammal from a mosquito as part of their life cycle. Upon entering the mammalian host, extracellular malaria sporozoites reach the liver and invade hepatocytes, wherein they meet the challenge of becoming replication-competent schizonts. During the process of conversion, the sporozoite selectively discards organelles that are unnecessary for the parasite growth in liver cells. Among the organelles that are cleared from the sporozoite are the micronemes, abundant secretory vesicles that facilitate the adhesion of the parasite to hepatocytes. Organelles specialized in sporozoite motility and structure, such as the inner membrane complex (a major component of the motile parasite's cytoskeleton), are also eliminated from converting parasites. The high degree of sophistication of the metamorphosis that occurs at the onset of the liver-form development cascade suggests that the observed changes must be multifactorial. Among the mechanisms implicated in the elimination of sporozoite organelles, the degradative process called autophagy contributes to the remodelling of the parasite interior and the production of replicative liver forms. In a broader context, the importance of the role played by autophagy during the differentiation of protozoan parasites that cycle between insects and vertebrates is nowadays clearly emerging. An exciting prospect derived from these observations is that the parasite proteins involved in the autophagic process may represent new targets for drug development.
7
Sanyal, Sohini, Stéphane Egée, Guillaume Bouyer, et al. "Plasmodium falciparum STEVOR proteins impact erythrocyte mechanical properties." Blood 119, no. 2 (2012): e1-e8. http://dx.doi.org/10.1182/blood-2011-08-370734.
Full textAbstract:
Infection of erythrocytes with the human malaria parasite, Plasmodium falciparum, results in dramatic changes to the host cell structure and morphology. The predicted functional localization of the STEVOR proteins at the erythrocyte surface suggests that they may be involved in parasite-induced modifications of the erythrocyte membrane during parasite development. To address the biologic function of STEVOR proteins, we subjected a panel of stevor transgenic parasites and wild-type clonal lines exhibiting different expression levels for stevor genes to functional assays exploring parasite-induced modifications of the erythrocyte membrane. Using this approach, we show that stevor expression impacts deformability of the erythrocyte membrane. This process may facilitate parasite sequestration in deep tissue vasculature.
8
WOOTTON, EMMA C., EDWARD C. POPE, CLAIRE L. VOGAN, EMILY C. ROBERTS, CHARLOTTE E. DAVIES, and ANDREW F. ROWLEY. "Morphology and pathology of the ectoparasitic copepod, Nicothoë astaci (‘lobster louse’) in the European lobster, Homarus gammarus." Parasitology 138, no. 10 (2011): 1285–95. http://dx.doi.org/10.1017/s003118201100093x.
Full textAbstract:
SUMMARYEctoparasitic copepods have been reported in a wide range of aquatic animals, including crustacean shellfish. However, with the exception of the salmon louse, Lepeophtheirus salmonis, our knowledge of such parasites in commercial species is rudimentary. The current study examines the morphology and pathology of the parasitic copepod, Nicothoë astaci (the ‘lobster louse’) in its host, the European lobster, Homarus gammarus. Lobsters were sampled from waters surrounding Lundy Island (Bristol Channel, UK) and all individuals collected were found to harbour female adult N. astaci in their gills, with a mean of 47·3 parasites/lobster. The majority of N. astaci were found in the basal region of pleurobranch gills. The parasite was found to attach to gill filaments via its oral sucker, maxillae and maxillipeds, and to feed on host haemolymph (blood) through a funnel-like feeding channel. It caused varying degrees of damage to the host gill, including occlusion of gill filaments and disruption to the vascular system in the central axis. Although there was evidence of extensive host response (haemocytic infiltration) to the parasite, it was displaced from the parasite attachment site and thus was observed in the central gill axis below. The region of gill filament immediately underlying the parasite feeding channel was devoid of such activity suggesting that the parasite interferes with the cellular defence and haemostatic mechanisms of the lobster in order to maintain invasion of the host.
9
Grabda-Kazubska, B., V. Kiseliene, and Ch Bayssade-Dufour. "Morphology and chaetotaxy ofEchinochasmussp. cercaria (Trematoda, Echinochasmidae)." Annales de Parasitologie Humaine et Comparée 66, no. 6 (1991): 263–68. http://dx.doi.org/10.1051/parasite/1991666263.
Full text
10
Poulin, Robert, and William J. Hamilton. "The Hamilton and Zuk Hypothesis Revisited: a Meta-Analytical Approach." Behaviour 134, no. 3-4 (1997): 299–320. http://dx.doi.org/10.1163/156853997x00485.
Full textAbstract:
AbstractThe Hamilton & Zuk (1982) hypothesis of parasite-mediated sexual selection has been the subject of both inter- and intraspecific tests. Past reviews have used vote counting to determine whether this hypothesis is supported by empirical evidence. This study reanalysed 199 separate quantitative assessments of a central prediction of the Hamilton & Zuk hypothesis using meta-analytical techniques. Overall, our meta-analysis showed that there was a significant negative effect of parasites on male showiness as predicted. However the magnitude of this effect varied between host taxa and between endo and ectoparasitic taxa. As a whole intraspecific correlations between parasite load and male showiness provided very little support for the hypothesis with only the effect of parasites on fish morphology matching the Hamilton & Zuk prediction. There was more support for the hypothesis from interspecific studies especially those based upon the original Hamilton & Zuk (1982) data set, although other bird studies provided weaker support. The generality of the Hamilton & Zuk hypothesis in respect to parasite mediated sexual selection across taxa is thrown into doubt by these results. However, in some specific host-parasite systems the role of parasites appears important and future intraspecific tests of parasite-mediated sexual selection should perhaps focus on such systems.
11
BRYAN, HEATHER M., CHRIS T. DARIMONT, JANET E. HILL, et al. "Seasonal and biogeographical patterns of gastrointestinal parasites in large carnivores: wolves in a coastal archipelago." Parasitology 139, no. 6 (2012): 781–90. http://dx.doi.org/10.1017/s0031182011002319.
Full textAbstract:
SUMMARYParasites are increasingly recognized for their profound influences on individual, population and ecosystem health. We provide the first report of gastrointestinal parasites in gray wolves from the central and north coasts of British Columbia, Canada. Across 60 000 km2, wolf feces were collected from 34 packs in 2005–2008. At a smaller spatial scale (3300 km2), 8 packs were sampled in spring and autumn. Parasite eggs, larvae, and cysts were identified using standard flotation techniques and morphology. A subset of samples was analysed by PCR and sequencing to identify tapeworm eggs (n=9) andGiardiacysts (n=14). We detected ⩾14 parasite taxa in 1558 fecal samples.Sarcocystissporocysts occurred most frequently in feces (43·7%), followed by taeniid eggs (23·9%),Diphyllobothriumeggs (9·1%),Giardiacysts (6·8%),Toxocara caniseggs (2·1%), andCryptosporidiumoocysts (1·7%). Other parasites occurred in ⩽1% of feces. Genetic analyses revealedEchinococcus canadensisstrains G8 and G10,Taenia ovis krabbei, Diphyllobothrium nehonkaiense,andGiardia duodenalisassemblages A and B. Parasite prevalence differed between seasons and island/mainland sites. Patterns in parasite prevalence reflect seasonal and spatial resource use by wolves and wolf-salmon associations. These data provide a unique, extensive and solid baseline for monitoring parasite community structure in relation to environmental change.
12
Warring, Sally D., Zhicheng Dou, Vern B. Carruthers, Geoffrey I. McFadden, and Giel G. van Dooren. "Characterization of the Chloroquine Resistance Transporter Homologue in Toxoplasma gondii." Eukaryotic Cell 13, no. 11 (2014): 1360–70. http://dx.doi.org/10.1128/ec.00027-14.
Full textAbstract:
ABSTRACT Mutations in the Plasmodium falciparum chloroquine resistance transporter ( Pf CRT) protein confer resistance to the antimalarial drug chloroquine. Pf CRT localizes to the parasite digestive vacuole, the site of chloroquine action, where it mediates resistance by transporting chloroquine out of the digestive vacuole. Pf CRT belongs to a family of transporter proteins called the chloroquine resistance transporter family. CRT family proteins are found throughout the Apicomplexa, in some protists, and in plants. Despite the importance of Pf CRT in drug resistance, little is known about the evolution or native function of CRT proteins. The apicomplexan parasite Toxoplasma gondii contains one CRT family protein. We demonstrate that T. gondii CRT ( Tg CRT) colocalizes with markers for the vacuolar (VAC) compartment in these parasites. The Tg CRT-containing VAC is a highly dynamic organelle, changing its morphology and protein composition between intracellular and extracellular forms of the parasite. Regulated knockdown of Tg CRT expression resulted in modest reduction in parasite fitness and swelling of the VAC, indicating that Tg CRT contributes to parasite growth and VAC physiology. Together, our findings provide new information on the role of CRT family proteins in apicomplexan parasites.
13
Gupta, Nishith, Matthew M. Zahn, Isabelle Coppens, Keith A. Joiner, and Dennis R. Voelker. "Selective Disruption of Phosphatidylcholine Metabolism of the Intracellular ParasiteToxoplasma gondiiArrests Its Growth." Journal of Biological Chemistry 280, no. 16 (2005): 16345–53. http://dx.doi.org/10.1074/jbc.m501523200.
Full textAbstract:
Toxoplasma gondiiis an intracellular protozoan parasite capable of causing devastating infections in immunocompromised and immunologically immature individuals. In this report, we demonstrate the relative independence ofT. gondiifrom its host cell for aminoglycerophospholipid synthesis. The parasite can acquire the lipid precursors serine, ethanolamine, and choline from its environment and use them for the synthesis of its major lipids, phosphatidylserine (PtdSer), phosphatidylethanolamine (PtdEtn), and phosphatidylcholine (PtdCho), respectively. Dimethylethanolamine (Etn(Me)2), a choline analog, dramatically interfered with the PtdCho metabolism ofT. gondiiand caused a marked inhibition of its growth within human foreskin fibroblasts. In tissue culture medium supplemented with 2 mmEtn(Me)2, the parasite-induced lysis of the host cells was dramatically attenuated, and the production of parasites was inhibited by more than 99%. The disruption of parasite growth was paralleled by structural abnormalities in its membranes. In contrast, no negative effect on host cell growth and morphology was observed. The data also reveal that the Etn(Me)2-supplemented parasite had a time-dependent decrease in its PtdCho content and an equivalent increase in phosphatidyldimethylethanolamine, whereas other major lipids, PtdSer, PtdEtn, and PtdIns, remained largely unchanged. Relative to host cells, the parasites incorporated more than 7 times as much Etn(Me)2into their phospholipid. These findings reveal that Etn(Me)2selectively alters parasite lipid metabolism and demonstrate how selective inhibition of PtdCho synthesis is a powerful approach to arresting parasite growth.
14
Kristan, Deborah M. "Effects of intestinal nematodes during lactation: consequences for host morphology, physiology and offspring mass." Journal of Experimental Biology 205, no. 24 (2002): 3955–65. http://dx.doi.org/10.1242/jeb.205.24.3955.
Full textAbstract:
SUMMARYSublethal parasites are often assumed to have no detrimental effects on their host. However, the sublethal intestinal nematode Heligmosomoides polygyrus affects both the morphology and the physiology of its laboratory mouse (Mus musculus) host and therefore has the potential to affect host life history. The objectives of the present study were to determine (1) whether lactating and non-lactating mice responded similarly to experimental infection with H. polygyrus and (2) whether the changes in morphology and physiology that occurred with parasite infection affected host reproductive performance. Parasitized mice had greater whole body mass as a result of greater lean mass compared with unparasitized mice. Parasitized mice had larger organs (spleen, stomach, cecum and small intestine) and a diminished rate of glucose transport by the small intestine compared with unparasitized mice. Lactating mice had larger organs (liver, kidney, spleen,heart, stomach, large intestine, cecum and small intestine), lean mass and whole body mass, but a similar rate of glucose transport compared with virgin mice. Resting metabolism increased with lactation but not with parasitism. Lactating and non-lactating mice responded similarly to parasite infection for most measured variables. Production of large litters was followed by production of small litters for parasitized but not unparasitized females. After adjusting for parity and litter size, parasitized mothers produced female pups that were 6% smaller at weaning than female pups from unparasitized mothers, but there was no effect of maternal parasite infection on mass at weaning for male pups. Other measures of reproductive output were not affected by parasite infection.
15
SANTARÉM, NUNO, JOANA CUNHA, RICARDO SILVESTRE, et al. "The impact of distinct culture media inLeishmania infantumbiology and infectivity." Parasitology 141, no. 2 (2013): 192–205. http://dx.doi.org/10.1017/s0031182013001388.
Full textAbstract:
SUMMARYAn ideal culture medium forLeishmaniapromastigotes should retain the basic characteristics of promastigotes found in sandflies (morphology and infectivity). Furthermore, the media should not create a bias in experimental settings, thus enabling the proper extrapolation of results. To assess this we studied several established media for promastigote growth. We analysed morphology, viability, cell cycle progression, metacyclic profile, capacity to differentiate into axenic amastigotes and infectivity. Furthermore, using a rational approach from the evaluated media we developed a simple serum-free medium (cRPMI). We report that parasites growing in different media present different biological characteristics and distinctin vitroandin vivoinfectivities. The developed medium, cRPMI, proved to be a less expensive substitute for traditional serum-supplemented media for thein vitromaintenance of promastigotes. In fact, cRPMI is ideal for the maintenance of parasites in the laboratory, diminishing the expected loss of virulence over time typical of the parasite cultivation. Ultimately this report is a clear warning that the normalization of culture media should be a real concern in the field as media-specific phenomena are sufficient to induce biological bias with consequences in infectivity and general parasite biology.
16
Kristan, Deborah M. "Maternal and direct effects of the intestinal nematode Heligmosomoides polygyrus on offspring growth and susceptibility to infection." Journal of Experimental Biology 205, no. 24 (2002): 3967–77. http://dx.doi.org/10.1242/jeb.205.24.3967.
Full textAbstract:
SUMMARY The laboratory mouse (Mus musculus) has a naturally occurring intestinal nematode (Heligmosomoides polygyrus) that induces an immune response, causes phenotypic plasticity in metabolism and in organ structure and function, and results in changes in host reproductive output. The objectives of the present study were to determine (1) whether pups infected with parasites at weaning grew differently and had a different body composition at adulthood compared with uninfected pups, (2) whether offspring from parasitized mothers grew differently and had a different body composition at adulthood compared with offspring from unparasitized mothers, (3) whether parasite effects on body composition of pups varied under different infection intensities and (4) whether maternal parasite infection affected susceptibility, duration and intensity of offspring parasite infection. H. polygyrus had direct and maternal effects on offspring growth, but final adult mass was not affected by parasites. Parasite infection in offspring had no effect on overall fat mass, but mass changes for some organs were greater for mice that had a high infection intensity compared with mice that had a low infection intensity. Only offspring from parasitized mothers cleared their parasite infection; however, if the infection was not cleared, the final infection intensity was greater for offspring born to parasitized mothers than to unparasitized mothers. This study shows that chronic, sublethal parasite infection with H. polygyrus has both maternal and direct effects that induce physiological changes in growing mice sufficient to alter host growth trajectories, morphology and susceptibility to parasite infection.
17
Hatton, Olivia, Lea Stitzlein, Richard W. Dudley, and Robert A. Charvat. "Evaluating the Antiparasitic Activity of Novel BPZ Derivatives Against Toxoplasma gondii." Microorganisms 8, no. 8 (2020): 1159. http://dx.doi.org/10.3390/microorganisms8081159.
Full textAbstract:
Prevalence studies revealed that one-third of the human population is chronically infected with Toxoplasma gondii. Presently, such infections are without medical treatment that effectively eradicates the parasite once it is in its latent form. Moreover, the therapeutics used to treat acute infections are poorly tolerated by patients and also cause the parasite to convert into long-lasting tissue cysts. Hence, there is a dire need for compounds with antiparasitic activity against all forms of T. gondii. This study examines the antiparasitic capacity of nine novel bisphenol Z (BPZ) derivatives to determine whether they possessed any activity that prevented T. gondii replication. To begin assessing the efficacy of the novel derivatives, parasites were treated with increasing concentrations of the compounds, then doubling assays and MitoTracker staining were performed. Three of the nine compounds demonstrated strong inhibitory activity, i.e., parasite replication significantly decreased with higher concentrations. Additionally, many of the treated parasites exhibited decreases in fluorescent signaling and disruption of mitochondrial morphology. These findings suggest that bisphenol Z compounds disrupt mitochondrial function to inhibit parasite replication and may provide a foundation for the development of new and effective treatment modalities against T. gondii.
18
Morales, Miguel A., Pascale Pescher, and Gerald F. Späth. "Leishmania major MPK7 Protein Kinase Activity Inhibits Intracellular Growth of the Pathogenic Amastigote Stage." Eukaryotic Cell 9, no. 1 (2009): 22–30. http://dx.doi.org/10.1128/ec.00196-09.
Full textAbstract:
ABSTRACT During the infectious cycle, protozoan parasites of the genus Leishmania undergo several adaptive differentiation steps that are induced by environmental factors and crucial for parasite infectivity. Genetic analyses of signaling proteins underlying Leishmania stage differentiation are often rendered difficult due to lethal null mutant phenotypes. Here we used a transgenic strategy to gain insight into the functions of the mitogen-activated Leishmania major protein kinases LmaMPK7 and LmaMPK10 in parasite virulence. We established L. major and Leishmania donovani lines expressing episomal green fluorescent protein (GFP)-LmaMPK7 and GFP-LmaMPK10 fusion proteins. The transgenic lines were normal in promastigote morphology, growth, and the ability to differentiate into metacyclic and amastigote stages. While parasites expressing GFP-LmaMPK10 showed normal infectivity by mouse footpad analysis and macrophage infection assays, GFP-LmaMPK7 transgenic parasites displayed a strong delay in lesion formation and reduced intracellular parasite growth. Significantly, the effects of GFP-LmaMPK7 on virulence and proliferation were due exclusively to protein kinase activity, as the overexpression of two kinase-dead mutants had no effect on parasite infectivity. GFP-LmaMPK7 transgenic L. donovani cells revealed a reversible, stage-specific growth defect in axenic amastigotes that was independent of cell death but linked to nonsynchronous growth arrest and a significant reduction of de novo protein biosynthesis. Our data suggest that LmaMPK7 protein kinase activity may be implicated in parasite growth control and thus relevant for the development of nonproliferating stages during the infectious cycle.
19
Murcia Zapata, Karen Nataly, María Paula Romero Cerón, Graciela Juez Castillo, and Brayan Alfonso Valencia Vidal. "Pattern Recognition Algorithm for Automatic Quantification of Toxoplasma gondii Tachyzoites." Ingeniería 26, no. 1 (2020): 93–110. http://dx.doi.org/10.14483/23448393.16102.
Full textAbstract:
Context: Digital image processing is an efficient and suitable computational tool for the automatic quantification of human pathogens in images, providing analysis in less time, greater number of samples, and result reproducibility. We propose the development and validation of an image processing algorithm, for the recognition and automatic quantification of T. gondii tachyzoites. Method: We developed an algorithm based on image processing. This workflow allows identifying the morphology of each parasite in the image by determining the number of parasites distinguishing them from those with a similar morphology, but not corresponding to the parasite in question. Images were obtained through Giemsa staining protocols. Results: The original images were analyzed by experts. The results showed correlation with those obtained by the automatic count. Additionally, a processing time of 5 seconds per image was obtained with the algorithm. This automated quantification tool allowed count of tachyzoites in tens of images. Conclusions: This automatic image analysis tool can extend its implementation to any laboratory that is involved in the quantification of extracellular Toxoplasma gondii tachyzoites, as well as other aspects of research on its tachyzoites that require the count of this form of development of the parasite.
20
Boijink, C. L., P. O. Maciel, M. Tavares-Dias, et al. "Anesthesia by sprinkling method in the gills of tambaqui Colossoma macropomum does not influence intensity and morphology of monogeneans." Brazilian Journal of Biology 77, no. 2 (2016): 367–71. http://dx.doi.org/10.1590/1519-6984.15915.
Full textAbstract:
Abstract The present study evaluates the influence of anesthesia on the parasitic fauna of monogenea fish parasites, as its intensity and viability. Two experiments were conducted: Evaluation of an anesthetic method by sprinkling eugenol directly on gills and evaluation of monogenea motility and viability; Comparison of immersion and directly sprinkling on the gills with benzocaine and eugenol followed by evaluation on parasite intensity. The results suggest that the anesthetic sprinkling didn’t interfere in the parasite motility, morphology and body surface integrity analyzed by fluorescence method. The monogenean intensity in the gills was lower in fish anesthetized by immersion method compared to the sprinkling method and the control group. This method of anesthesia can be used in parasitological studies.
21
Šimková, Andrea, Celine Serbielle, Antoine Pariselle, Maarten P. M. Vanhove, and Serge Morand. "Speciation inThaparocleidus(Monogenea: Dactylogyridae) Parasitizing Asian Pangasiid Catfishes." BioMed Research International 2013 (2013): 1–14. http://dx.doi.org/10.1155/2013/353956.
Full textAbstract:
The phylogeny of monogeneans of the genusThaparocleidusthat parasitize the gills of Pangasiidae in Borneo and Sumatra was inferred from molecular data to investigate parasite speciation. The phylogeny of the Pangasiidae was also reconstructed in order to investigate host-parasite coevolutionary history. The monophyly ofThaparocleidusparasitizing Pangasiidae was confirmed. Low intraspecies molecular variability was observed in threeThaparocleidusspecies collected from geographically distant localities. However, a high intraspecies molecular variability was observed in twoThaparocleidusspecies suggesting that these species represent a complex of species highly similar in morphology. Distance-based and tree-based methods revealed a significant global fit between parasite and host phylogenies. Parasite duplication (i.e., intrahost speciation) was recognized as the most common event inThaparocleidus, while the numbers of cospeciation and host switches were lower and similar to each other. When collapsing nodes correspond to duplication cases, our results suggest host switches in theThaparocleidus-Pangasiidae system precluding congruence between host and parasite trees. We found that the morphometric variability of the parasite attachment organ is not linked to phylogeny, suggesting that the attachment organ is under adaptive constraint. We showed that haptor morphometry is linked to host specificity, whereby nonspecific parasites display higher morphometric variability than specialists.
22
LOVY, J., and S. E. FRIEND. "Phylogeny and morphology of Ovipleistophora diplostomuri n. sp. (Microsporidia) with a unique dual-host tropism for bluegill sunfish and the digenean parasite Posthodiplostomum minimum (Strigeatida)." Parasitology 144, no. 14 (2017): 1898–911. http://dx.doi.org/10.1017/s0031182017001305.
Full textAbstract:
SUMMARYMicrosporidia are diverse opportunistic parasites abundant in aquatic organisms with some species hyperparasitic in digenean parasites. In the current study, we describe a unique microsporidian parasite, Ovipleistophora diplostomuri n. sp. that has a tropism for both the bluegill sunfish Lepomis macrochirus, and its digenean parasite Posthodiplostomum minimum. Though the microsporidium first infects a fish, the subsequent infection causes hypertrophy of the metacercarial wall and degeneration of the P. minimum metacercariae within the fish tissue. Genetic analysis placed this species within Ovipleistophora and ultrastructural characteristics were consistent with the genus, including the presence of dimorphic spores within sporophorous vesicles. Meronts did not have a surface coat of dense material, which has been previously reported for the genus. This is the first Ovipleistophora species described that does not have a tropism for ovary. Genetics demonstrated that O. diplostomuri n. sp. groups closely within fish microsporidia and not other species known to be hyperparasitic in digeneans, suggesting that it evolved from fish-infecting microsporidians and developed a secondary tropism for a common and widespread digenean parasite. The high genetic identity to Ovipleistophora species demonstrates the close relationship of this unique microsporidian with other microsporidia that infect ovary.
23
Parmentier, Eric, Déborah Lanterbecq, and Igor Eeckhaut. "From commensalism to parasitism in Carapidae (Ophidiiformes): heterochronic modes of development?" PeerJ 4 (March 10, 2016): e1786. http://dx.doi.org/10.7717/peerj.1786.
Full textAbstract:
Phenotypic variations allow a lineage to move into new regions of the adaptive landscape. The purpose of this study is to analyse the life history of the pearlfishes (Carapinae) in a phylogenetic framework and particularly to highlight the evolution of parasite and commensal ways of life. Furthermore, we investigate the skull anatomy of parasites and commensals and discuss the developmental process that would explain the passage from one form to the other. The genusCarapusforms a paraphyletic grouping in contrast to the genusEncheliophis, which forms a monophyletic cluster. The combination of phylogenetic, morphologic and ontogenetic data clearly indicates that parasitic species derive from commensal species and do not constitute an iterative evolution from free-living forms. Although the head morphology ofCarapusspecies differs completely fromEncheliophis,C. homeiis the sister group of the parasites. Interestingly, morphological characteristics allowing the establishment of the relation betweenCarapus homeiandEncheliophisspp. concern the sound-producing mechanism, which can explain the diversification of the taxon but not the acquisition of the parasite morphotype.Carapus homeialready has the sound-producing mechanism typically found in the parasite form but still has a commensal way of life and the corresponding head structure. Moreover, comparisons between the larval and adult Carapini highlight that the adult morphotype “Encheliophis” is obtained by going beyond the adult stage reached byCarapus. The entrance into the new adaptive landscape could have been realised by at least two processes: paedomorphosis and allometric repatterning.
24
Xie, W., G. R. Racz, B. S. Terry, and S. L. Gardner. "A method for measuring the attachment strength of the cestode Hymenolepis diminuta to the rat intestine." Journal of Helminthology 91, no. 6 (2016): 762–66. http://dx.doi.org/10.1017/s0022149x1600078x.
Full textAbstract:
AbstractA unique adaptation of many internal parasites of mammals is their ability to stay in the intestine for extended periods of time and resist the normal peristaltic movements and forces that push and expel material. To better understand parasite adhesion behaviour and replicate their attachment method in medical devices, an experiment was designed and performed using the rat tapeworm, Hymenolepis diminuta. The experiment employed a tensile test machine and a digital scale and was designed to calculate the attachment strength of the scolex to the mucosa through the change of the value of the digital scale during the tensile test. The attachment force of H. diminuta is 0.021 ± 0.011 g. This method could be applied in studies of parasite biomechanics and the results may help medical device researchers to better mimic the unique functional morphology of this species of parasite.
25
de Castro Demoner, Larissa, Maria Regina Lucas da Silva, Natalia Mizuhira Magro, and Lucia Helena O'Dwyer. "Hepatozoon milleri sp. nov. (Adeleorina: Hepatozoidae) in Akodon montensis (Rodentia: Cricetidae: Sigmodontinae) from southeastern Brazil." Parasitology 146, no. 5 (2018): 662–69. http://dx.doi.org/10.1017/s0031182018001956.
Full textAbstract:
AbstractMembers of the genus Hepatozoon (Miller, 1908) are blood parasites found in a wide range of host species, including wild rodents; however, information about the life cycle, distribution and Hepatozoon species diversity infecting these mammals are lacking. We studied the parasite stages and DNA sequences of Hepatozoon sp. of 11 naturally infected Akodon montensis. Thin blood smears, tissue samples and whole blood were obtained for morphology, morphometry and molecular analyses. Seven of the 11 rodents had gamonts on the blood smears. Biological and morphological features of the parasite such as tissue tropism, gamonts and meronts size and morphology, as well as the DNA sequence comparison and phylogenetic analysis, indicated that the Hepatozoon sp. detected in this study is distinct from those species previously reported in small rodents. Herein, we propose a new species, named Hepatozoon milleri sp. nov. This is the first description of a new Hepatozoon species from wild small rodents in Brazil, based on morphological and molecular characteristics.
26
Urca, Hadas, and Frida Ben-Ami. "The role of spore morphology in horizontal transmission of a microsporidium of Daphnia." Parasitology 145, no. 11 (2018): 1452–57. http://dx.doi.org/10.1017/s0031182018000392.
Full textAbstract:
AbstractThe microsporidian parasite Hamiltosporidium tvaerminnensis can infect Daphnia magna both horizontally (through environmental spores) and vertically (through parthenogenetic and sexually produced eggs). The spores of H. tvaerminnensis come in three distinguishable morphologies, which are thought to have different roles in the transmission of the parasite. In this study, we examined the role of the two most common spore morphologies (i.e. oval-shaped spores and pear-shaped spores) in horizontal transmission of H. tvaerminnensis. To this end, we infected hosts with solutions consisting of either mostly oval- or mostly pear-shaped spores, and quantified infection rates, parasite-induced host mortality and mean number of parasite spores produced per host. We found that spore morphology by itself did not influence infection rates and parasite-induced host mortality. Instead, host clone and parasite isolate interacted with spore morphology in shaping infection outcome and mortality. Thus, there appear to be strong genotype-by-genotype (G × G) interactions in this system. While there is no dispute that H. tvaerminnensis can transmit both vertically and horizontally, our findings do not support theoretical predictions that different spore morphologies hold different roles in horizontal transmission of H. tvaerminnensis.
27
DINGEMANSE, NIELS J., CHRIS OOSTERHOF, FONS VAN DER PLAS, and IAIN BARBER. "Variation in stickleback head morphology associated with parasite infection." Biological Journal of the Linnean Society 96, no. 4 (2009): 759–68. http://dx.doi.org/10.1111/j.1095-8312.2008.01179.x.
Full text
28
Miura, Osamu, Armand M. Kuris, Mark E. Torchin, Ryan F. Hechinger, and Satoshi Chiba. "Parasites alter host phenotype and may create a new ecological niche for snail hosts." Proceedings of the Royal Society B: Biological Sciences 273, no. 1592 (2006): 1323–28. http://dx.doi.org/10.1098/rspb.2005.3451.
Full textAbstract:
By modifying the behaviour and morphology of hosts, parasites may strongly impact host individuals, populations and communities. We examined the effects of a common trematode parasite on its snail host, Batillaria cumingi (Batillariidae). This widespread snail is usually the most abundant invertebrate in salt marshes and mudflats of the northeastern coast of Asia. More than half (52.6%, n =1360) of the snails in our study were infected. We found that snails living in the lower intertidal zone were markedly larger and exhibited different shell morphology than those in the upper intertidal zone. The large morphotypes in the lower tidal zone were all infected by the trematode, Cercaria batillariae (Heterophyidae). We used a transplant experiment, a mark-and-recapture experiment and stable carbon isotope ratios to reveal that snails infected by the trematode move to the lower intertidal zone, resume growth after maturation and consume different resources. By simultaneously changing the morphology and behaviour of individual hosts, this parasite alters the demographics and potentially modifies resource use of the snail population. Since trematodes are common and often abundant in marine and freshwater habitats throughout the world, their effects potentially alter food webs in many systems.
29
Francisco, C. J., M. A. Hermida, and M. J. Santos. "Prosorhynchus crucibulum(Digenea: Bucephalidae) miracidium morphology and its passive transmission pattern." Parasite 19, no. 3 (2012): 277–80. http://dx.doi.org/10.1051/parasite/2012193277.
Full text
30
Spallek, Thomas, Charles W. Melnyk, Takanori Wakatake, et al. "Interspecies hormonal control of host root morphology by parasitic plants." Proceedings of the National Academy of Sciences 114, no. 20 (2017): 5283–88. http://dx.doi.org/10.1073/pnas.1619078114.
Full textAbstract:
Parasitic plants share a common anatomical feature, the haustorium. Haustoria enable both infection and nutrient transfer, which often leads to growth penalties for host plants and yield reduction in crop species. Haustoria also reciprocally transfer substances, such as RNA and proteins, from parasite to host, but the biological relevance for such movement remains unknown. Here, we studied such interspecies transport by using the hemiparasitic plant Phtheirospermum japonicum during infection of Arabidopsis thaliana. Tracer experiments revealed a rapid and efficient transfer of carboxyfluorescein diacetate (CFDA) from host to parasite upon formation of vascular connections. In addition, Phtheirospermum induced hypertrophy in host roots at the site of infection, a form of enhanced secondary growth that is commonly observed during various parasitic plant–host interactions. The plant hormone cytokinin is important for secondary growth, and we observed increases in cytokinin and its response during infection in both host and parasite. Phtheirospermum-induced host hypertrophy required cytokinin signaling genes (AHK3,4) but not cytokinin biosynthesis genes (IPT1,3,5,7) in the host. Furthermore, expression of a cytokinin-degrading enzyme in Phtheirospermum prevented host hypertrophy. Wild-type hosts with hypertrophy were smaller than ahk3,4 mutant hosts resistant to hypertrophy, suggesting hypertrophy improves the efficiency of parasitism. Taken together, these results demonstrate that the interspecies movement of a parasite-derived hormone modified both host root morphology and fitness. Several microbial and animal plant pathogens use cytokinins during infections, highlighting the central role of this growth hormone during the establishment of plant diseases and revealing a common strategy for parasite infections of plants.
31
Thornhill, Randy, Kristine Johnson, J. David Ligon, and Marlene Zuk. "Parasites and Male Ornaments in Free-Ranging and Captive Red Jungle Fowl." Behaviour 114, no. 1-4 (1990): 232–48. http://dx.doi.org/10.1163/156853990x00149.
Full textAbstract:
AbstractThe morphology and parasite burdens of culled free-ranging red jungle fowl (Gallus gallus) from the San Diego Zoo were compared with those of captive roosters used previously in sexual selection experiments, to determine if results obtained with the captive birds were relevant to more natural situations. Zoo roosters had three helminth gut parasites: Ascaridia galli, tapeworms, and Heterakis. Parasite distribution was generally over-dispersed, with most individuals having none or few worms and some having heavy parasite burdens. These levels were comparable to those artificially induced in test roosters. The appearance of the zoo birds was similar to test roosters as well. Higher parasite burdens in the zoo birds was negatively related to hackle feather redness, comb length, and especially testis volume. The latter finding is discussed in light of information about the relationship between testosterone levels, sexual selection, and the immune system. A new analysis of female choice of uninfected controls versus experimentally infected roosters suggests that females prefer a multivariate array of traits perceived as a continuous, rather than categorical, variable.
32
Duffy, Meghan A., Timothy Y. James, and Alan Longworth. "Ecology, Virulence, and Phylogeny of Blastulidium paedophthorum, a Widespread Brood Parasite of Daphnia spp." Applied and Environmental Microbiology 81, no. 16 (2015): 5486–96. http://dx.doi.org/10.1128/aem.01369-15.
Full textAbstract:
ABSTRACTParasitism is now recognized as a major factor impacting the ecology and evolution of plankton, includingDaphnia. Parasites that attack the developing embryos of daphniids, known as brood parasites, were first described in the early 1900s but have received relatively little study. Here, we link previous morphological descriptions of the oomycete brood parasiteBlastulidium paedophthorumwith information on its phylogenetic placement, ecology, and virulence. Based on the morphology and phylogenetic relationship with other members of theLeptomitales, we show that a brood parasite observed in daphniids in the Midwestern United States isB. paedophthorum. We used morphology, DNA sequences, and laboratory infection experiments to show thatB. paedophthorumis a multihost parasite that can be transmitted between species and genera. A field survey of six hosts in 15 lakes revealed thatB. paedophthorumis common in all six host taxa (present on 38.3% of our host species-lake-sampling date combinations; the maximum infection prevalences were 8.7% of the population and 20% of the asexual adult female population). AlthoughB. paedophthorumwas observed in all 15 lakes, presence and infection prevalence varied among lakes. Infection withB. paedophthorumdid not reduce host life span but significantly impacted host fecundity. Theory predicts that parasites that affect host fecundity without affecting host life span should have the strongest impact on host population dynamics. Based on its virulence and commonness in natural populations and on the central role of daphniids in freshwater food webs, we predict thatB. paedophthorumwill influence daphniid ecology and evolution, as well as the larger food web.
33
Dahl, Erica L., Jennifer L. Shock, Bhaskar R. Shenai, Jiri Gut, Joseph L. DeRisi, and Philip J. Rosenthal. "Tetracyclines Specifically Target the Apicoplast of the Malaria Parasite Plasmodium falciparum." Antimicrobial Agents and Chemotherapy 50, no. 9 (2006): 3124–31. http://dx.doi.org/10.1128/aac.00394-06.
Full textAbstract:
ABSTRACT Tetracyclines are effective but slow-acting antimalarial drugs whose mechanism of action remains uncertain. To characterize the antimalarial mechanism of tetracyclines, we evaluated their stage-specific activities, impacts on parasite transcription, and effects on two predicted organelle targets, the apicoplast and the mitochondrion, in cultured Plasmodium falciparum. Antimalarial effects were much greater after two 48-h life cycles than after one cycle, even if the drugs were removed at the end of the first cycle. Doxycycline-treated parasites appeared morphologically normal until late in the second cycle of treatment but failed to develop into merozoites. Doxycycline specifically impaired the expression of apicoplast genes. Apicoplast morphology initially appeared normal in the presence of doxycycline. However, apicoplasts were abnormal in the progeny of doxycycline-treated parasites, as evidenced by a block in apicoplast genome replication, a lack of processing of an apicoplast-targeted protein, and failure to elongate and segregate during schizogeny. Replication of the nuclear and mitochondrial genomes and mitochondrial morphology appeared normal. Our results demonstrate that tetracyclines specifically block expression of the apicoplast genome, resulting in the distribution of nonfunctional apicoplasts into daughter merozoites. The loss of apicoplast function in the progeny of treated parasites leads to a slow but potent antimalarial effect.
34
Rannala, B. H. "Comparative evolutionary genetics of trematode parasites (Plagiorchiidae) and their anuran hosts." Canadian Journal of Zoology 70, no. 5 (1992): 993–1000. http://dx.doi.org/10.1139/z92-141.
Full textAbstract:
A study of five trematode species of the genera Glypthelmins and Haplometrana inhabiting anurans produced allozyme-based estimates of Nei's (1978) genetic distance ranging from 0.126 to 1.867. An estimate of trematode phylogeny is in agreement with earlier morphologically based phylogenetic hypotheses and is similar to the phylogeny for associated host ranid and hylid frogs based on rDNA and morphology. A comparison of the genetic distances observed among trematodes with those of their respective hosts suggests that host and parasite genetic distances are not significantly correlated. This is counter to expectations based on a molecular clock for protein evolution in hosts and parasites. These results may reflect (i) the effects of sampling error on genetic distance estimates, (ii) a non-clocklike rate of protein evolution in hosts and (or) parasites, (iii) temporally independent speciation events in associated host and parasite lineages, or (iv) the effects of host hybridization.
35
BOON, NELE A. M., WOUTER FANNES, SARA ROMBOUTS, KATJA POLMAN, FILIP A. M. VOLCKAERT, and TINE HUYSE. "Detecting hybridization in African schistosome species: does egg morphology complement molecular species identification?" Parasitology 144, no. 7 (2017): 954–64. http://dx.doi.org/10.1017/s0031182017000087.
Full textAbstract:
SUMMARYHybrid parasites may have an increased transmission potential and higher virulence compared to their parental species. Consequently, hybrid detection is critical for disease control. Previous crossing experiments showed that hybrid schistosome eggs have distinct morphotypes. We therefore compared the performance of egg morphology with molecular markers with regard to detecting hybridization in schistosomes. We studied the morphology of 303 terminal-spined eggs, originating from 19 individuals inhabiting a hybrid zone with natural crosses between the human parasite Schistosoma haematobium and the livestock parasite Schistosoma bovis in Senegal. The egg sizes showed a high variability and ranged between 92·4 and 176·4 µm in length and between 35·7 and 93·0 µm in width. No distinct morphotypes were found and all eggs resembled, to varying extent, the typical S. haematobium egg type. However, molecular analyses on the same eggs clearly showed the presence of two distinct partial mitochondrial cox1 profiles, namely S. bovis and S. haematobium, and only a single nuclear ITS rDNA profile (S. haematobium). Therefore, in these particular crosses, egg morphology appears not a good indicator of hybrid ancestry. We conclude by discussing strengths and limitations of molecular methods to detect hybrids in the context of high-throughput screening of field samples.
36
Tietze, Eleonor, Silvana V. Urquiza, and María Ornela Beltrame. "Paleoparasitological study of Holocene South American camelids (ca. 8970–470 years 14C BP) from an archaeological site, Southern Puna of Argentina (Antofagasta de la Sierra, Catamarca)." Holocene 31, no. 8 (2021): 1264–72. http://dx.doi.org/10.1177/09596836211011654.
Full textAbstract:
South American camelids (SAC) have occupied a central role in the development of Andean societies. They are widely distributed in South America and since ancient times are an important factor in Andean economies and social and ritual life. The archaeological site Punta de Peña 4 (PP4) is located in Antofagasta de la Sierra Basin (Southern Puna of Argentina). PP4 is a rock overhang and presents a large occupational sequence (early Holocene until historic times). The aim of this contribution is to study parasite diversity and the relationship among parasites and SAC through holocenic times in the Southern Puna of Argentina. Besides, differences in parasite egg preservation in the site were discussed. A total of 65 coprolites assigned to SAC were rehydratated, homogenized, filtered, allowed to spontaneous sedimentation and examined for parasite remains. Given the morphology of the coprolites, the biogeographic origin and the presence of coccidian oocysts of Eimeria macusaniensis in some of them, a camelid origin of the coprolites is suggested. This is the first paleoparasitological study from PP4, an archaeological site of Antofagasta de la Sierra, a key region in northwestern Argentina and Central Andes. Eleven taxa of parasites were found belonging to Apicomplexa, Platyhelminthes, and Nematoda. Specific parasite species of SAC were found, such as E. macusaniensis and Lamanema chavezi/Nematodirus lamae. A remarkable finding was the presence of Moniezia sp. and Strongyloides sp. in coprolites from different levels of PP4, pointing out the presence of these genera in native artiodactyls of the region previous to the arrival of Hispanic societies. Results displayed a change in the number of parasite taxa present in SAC through time. The parasite-SAC relation through time and differences in parasite egg preservation between levels and sectors (covered and uncovered) of the site are discussed.
37
Ferreira, Thalita C. S., Ismael P. Sauter, Lina Borda-Samper, et al. "Effect of DODAB Nano-Sized Cationic Bilayer Fragments against Leishmania amazonensis." Molecules 25, no. 23 (2020): 5741. http://dx.doi.org/10.3390/molecules25235741.
Full textAbstract:
The dioctadecyldimethylammonium bromide (DODAB) is a double-chained cationic lipid with potent bactericide and fungistatic activities; however, its toxicity on protozoan parasites is still unknown. Here, we show the antileishmanial activity of DODAB nano-sized cationic bilayer fragments on stationary-phase promastigotes and amastigotes of Leishmania amazonensis, the causative agent of cutaneous leishmaniasis. Upon treatment with DODAB, we analyzed the parasite surface zeta-potential, parasite viability, cellular structural modifications, and intracellular proliferation. The DODAB cytotoxic effect was dose-dependent, with a median effective concentration (EC50) of 25 µM for both life-cycle stages, comparable to the reported data for bacteria and fungi. The treatment with DODAB changed the membrane zeta-potential from negative to positive, compromised the parasite’s morphology, affected the cell size regulation, caused a loss of intracellular organelles, and probably dysregulated the plasma membrane permeability without membrane disruption. Moreover, the parasites that survived after treatment induced small parasitophorous vacuoles and failed to proliferate inside macrophages. In conclusion, DODAB displayed antileishmanial activity, and it remains to be elucidated how DODAB acts on the protozoan membrane. Understanding this mechanism can provide insights into the development of new parasite-control strategies.
38
Petrocelli, Iacopo, and Stefano Turillazzi. "Comparative morphology of Van der Vecht's organ inPolistessocial parasites: host ecology and adaptation of the parasite." Biological Journal of the Linnean Society 109, no. 2 (2013): 313–19. http://dx.doi.org/10.1111/bij.12053.
Full text
39
Siqueira, R. S., R. B. Lucena, R. R. Guerra, et al. "Erratic migration of Ascaridia hermaphrodita (Nematoda: Ascaridida) in a blue-fronted Amazon parrot (Amazona aestiva) from illegal wildlife trade: case report." Arquivo Brasileiro de Medicina Veterinária e Zootecnia 73, no. 2 (2021): 445–50. http://dx.doi.org/10.1590/1678-4162-12143.
Full textAbstract:
ABSTRACT Ascaridiasis by Ascaridia hermaphrodita is a common parasitic disease in blue-fronted Amazon parrots (Amazona aestiva) and the contamination occurs by ingestion of eggs. Illegal trade of wild birds can increase the frequency of visceral erratic migration by this parasite. Hence, this report describes the erratic migration of A. hermaphrodita and associated lesions in a blue-fronted Amazon parrot. This is a retrospective study, which originated from several apprehension of illegal birds in the state of Paraíba, Brazil. Necropsy revealed intense intestinal ascarid infestation. Hepatic lesions were also observed associated with the parasite migration. Stereoscopy allowed the identification of the morphology of the parasites. Summarizing, this condition in wild birds is not fully understood and may be associated with illegal trade.
40
Harris, Tajie H., John M. Mansfield, and Donna M. Paulnock. "CpG Oligodeoxynucleotide Treatment Enhances Innate Resistance and Acquired Immunity to African Trypanosomes." Infection and Immunity 75, no. 5 (2007): 2366–73. http://dx.doi.org/10.1128/iai.01649-06.
Full textAbstract:
ABSTRACTRelative resistance to African trypanosomiasis is based on the development of a type I cytokine response, which is partially dependent on innate immune responses generated through MyD88 and Toll-like receptor 9 (TLR9). Therefore, we asked whether enhancement of the immune response by artificial stimulation with CpG oligodeoxynucleotide (ODN), a TLR9 agonist, would result in enhanced protection against trypanosomes. In susceptible BALB/c mice, relative resistance to infection was significantly enhanced by CpG ODN treatment and was associated with decreased parasite burden, increased cytokine production, and elevated parasite-specific B- and T-cell responses. In relatively resistant C57BL/6 mice, survival was not enhanced but early parasitemia levels were reduced 100-fold and the majority of the parasites were nondividing, short stumpy (SS) forms. CpG ODN treatment of lymphocyte-deficient C57BL/6-scidand BALB/cByJ-scidmice also enhanced survival and reduced parasitemia, indicating that innate resistance to trypanosome infection can be enhanced. In C57BL/6-scidand BALB/cByJ-scidmice, the parasites were also predominantly SS forms during the outgrowth of parasitemia. However, the effect of CpG ODN treatment on parasite morphology was not as marked in gamma interferon (IFN-γ)-knockout mice, suggesting that downstream effects of IFN-γ production may play a discrete role in parasite cell differentiation. Overall, these studies provide the first evidence that enhancement of resistance to African trypanosomes can be induced in susceptible animals in a TLR9-dependent manner and that CpG ODN treatment may influence the developmental life cycle of the parasites.
41
Džamić, A. M., I. V. Čolović, V. S. Arsić-Arsenijević, et al. "Human Dirofilaria repens infection in Serbia." Journal of Helminthology 83, no. 2 (2009): 129–37. http://dx.doi.org/10.1017/s0022149x09341346.
Full textAbstract:
AbstractHuman infection by Dirofilaria repens in Serbia has been increasing steadily. The first case was reported in 1971, presented in the form of a single subcutaneous nodule on the back of a young boy. As established by a literature search, eight additional cases were reported until mid-2001. The most frequent site of infection was subcutaneous tissue, with the exception of two cases, in which parasites were found in subconjunctiva and epididymis. Our study, conducted from 2001 to 2008, encompasses 19 new cases. Most of them (63.1%) presented as ocular or periocular infections, in which the parasite was typically found under the conjunctiva. In other cases a parasitic nodule was localized in the temporal region of the head, epididymis, testicle, abdomen, breast or arm. The diagnosis was made by morphological and histological analysis of the extracted intact worms and parasite sections from the tissue. Morphology of the filarial worms was well preserved in more than half of the cases (12/19) and there was never more than one parasite found inside the lesions. Adult worms and immature nematodes were observed in nine and seven cases, respectively. Furthermore, in two cases microfilariae were discovered inside the pseudocoelom, sections of the female reproductive tubes filled with clearly visible larval stages. Dirofilaria repens infection was diagnosed by its morphological features (17/19) or by performing polymerase chain reactions (PCR) using paraffin-embedded tissues (2/19) in the cases where the morphology was insufficient for identification and the parasites had been determined initially as Dirofilaria spp. The amplified 246 bp PCR product showed that the worms were D. repens.
42
Sunter, Jack, and Keith Gull. "Shape, form, function and Leishmania pathogenicity: from textbook descriptions to biological understanding." Open Biology 7, no. 9 (2017): 170165. http://dx.doi.org/10.1098/rsob.170165.
Full textAbstract:
The shape and form of protozoan parasites are inextricably linked to their pathogenicity. The evolutionary pressure associated with establishing and maintaining an infection and transmission to vector or host has shaped parasite morphology. However, there is not a ‘one size fits all’ morphological solution to these different pressures, and parasites exhibit a range of different morphologies, reflecting the diversity of their complex life cycles. In this review, we will focus on the shape and form of Leishmania spp., a group of very successful protozoan parasites that cause a range of diseases from self-healing cutaneous leishmaniasis to visceral leishmaniasis, which is fatal if left untreated.
43
Downes, Barbara J. "Host-Induced Morphology in Mites: Implications for Host-Parasite Coevolution." Systematic Zoology 39, no. 2 (1990): 162. http://dx.doi.org/10.2307/2992453.
Full text
44
Leander, Brian S., Juan F. Saldarriaga, and Patrick J. Keeling. "Surface morphology of the marine parasite Haplozoon axiothellae Siebert (Dinoflagellata)." European Journal of Protistology 38, no. 3 (2002): 287–97. http://dx.doi.org/10.1078/0932-4739-00882.
Full text
45
Roth, Myron. "Morphology and development of the egg case in the parasitic copepod Haemobaphes intermedius Kabata, 1967 (Copepoda: Pennellidae)." Canadian Journal of Zoology 66, no. 11 (1988): 2573–77. http://dx.doi.org/10.1139/z88-378.
Full textAbstract:
Studies on the morphology of the egg sacs of the copepod parasite Haemobaphes intermedius Kabata, 1967 indicate that a distinctive change in appearance occurs once the egg sac is mature and ready to hatch. Highest rates of infection by copepodids occur where adults are found, suggesting a one-host life cycle. Clinocottus acuticeps is recorded as a new host for H. intermedius, as well as for Holobomolochus sp. and Clavella sp. The ecology of the tide pool is discussed in relation to intertidal fish parasites.
46
Huntley, John Warren, and Daniele Scarponi. "Parasitism and host behavior in the context of a changing environment: The Holocene record of the commercially important bivalve Chamelea gallina, northern Italy." PLOS ONE 16, no. 4 (2021): e0247790. http://dx.doi.org/10.1371/journal.pone.0247790.
Full textAbstract:
Rapid warming and sea-level rise are predicted to be major driving forces in shaping coastal ecosystems and their services in the next century. Though forecasts of the multiple and complex effects of temperature and sea-level rise on ecological interactions suggest negative impacts on parasite diversity, the effect of long term climate change on parasite dynamics is complex and unresolved. Digenean trematodes are complex life cycle parasites that can induce characteristic traces on their bivalve hosts and hold potential to infer parasite host-dynamics through time and space. Previous work has demonstrated a consistent association between sea level rise and increasing prevalence of trematode traces, but a number of fundamental questions remain unanswered about this paleoecological proxy. Here we examine the relationships of host size, shape, and functional morphology with parasite prevalence and abundance, how parasites are distributed across hosts, and how all of these relationships vary through time, using the bivalve Chamelea gallina from a Holocene shallow marine succession in the Po coastal plain. Trematode prevalence increased and decreased in association with the transition from a wave-influenced estuarine system to a wave-dominated deltaic setting. Prevalence and abundance of trematode pits are associated with large host body size, reflecting ontogenetic accumulation of parasites, but temporal trends in median host size do not explain prevalence trends. Ongoing work will test the roles of temperature, salinity, and nutrient availability on trematode parasitism. Parasitized bivalves in one sample were shallower burrowers than their non-parasitized counterparts, suggesting that hosts of trematodes can be more susceptible to their predators, though the effect is ephemeral. Like in living parasite-host systems, trematode-induced malformations are strongly aggregated among hosts, wherein most host individuals harbor very few parasites while a few hosts have many. We interpret trace aggregation to support the assumption that traces are a reliable proxy for trematode parasitism in the fossil record.
47
Theunissen, Maxine, Louwrens Tiedt, and Louis H. Du Preez. "The morphology and attachment ofProtopolystoma xenopodis(Monogenea: Polystomatidae) infecting the African clawed frogXenopus laevis." Parasite 21 (2014): 20. http://dx.doi.org/10.1051/parasite/2014020.
Full text
48
Linardi, Pedro Marcos, Jean-Claude Beaucournu, Daniel Moreira de Avelar, and Sorya Belaz. "Notes on the genusTunga(Siphonaptera: Tungidae) II – neosomes, morphology, classification, and other taxonomic notes." Parasite 21 (2014): 68. http://dx.doi.org/10.1051/parasite/2014067.
Full text
49
Hu, Jun-Jie, Si Huang, Tao Wen, Gerald W. Esch, Yu Liang, and Hong-Liang Li. "Sarcocystis spp. in domestic sheep in Kunming City, China: prevalence, morphology, and molecular characteristics." Parasite 24 (2017): 30. http://dx.doi.org/10.1051/parasite/2017025.
Full text
50
Taraschewski, H. "Hosts and parasites as aliens." Journal of Helminthology 80, no. 2 (2006): 99–128. http://dx.doi.org/10.1079/joh2006364.
Full textAbstract:
AbstractOver the past decades, various free-living animals (hosts) and their parasites have invaded recipient areas in which they had not previously occurred, thus gaining the status of aliens or exotics. In general this happened to a low extent for hundreds of years. With variable frequency, invasions have been followed by the dispersal and establishment of non-indigenous species, whether host or parasite. In the literature thus far, colonizations by both hosts and parasites have not been treated and reviewed together, although both are usually interwoven in various ways. As to those factors permitting invasive success and colonization strength, various hypotheses have been put forward depending on the scientific background of respective authors and on the conspicuousness of certain invasions. Researchers who have tried to analyse characteristic developmental patterns, the speed of dispersal or the degree of genetic divergence in populations of alien species have come to different conclusions. Among parasitologists, the applied aspects of parasite invasions, such as the negative effects on economically important hosts, have long been at the centre of interest. In this contribution, invasions by hosts as well as parasites are considered comparatively, revealing many similarities and a few differences. Two helminths, the liver fluke,Fasciola hepatica,of cattle and sheep and the swimbladder nematode,Anguillicola crassus,of eels are shown to be useful as model parasites for the study of animal invasions and environmental global change. Introductions ofF. hepaticahave been associated with imports of cattle or other grazing animals. In various target areas, susceptible lymnaeid snails serving as intermediate hosts were either naturally present and/or were introduced from the donor continent of the parasite (Europe) and/or from other regions which were not within the original range of the parasite, partly reflecting progressive stages of a global biota change. In several introduced areas,F. hepaticaco-occurs with native or exotic populations of the congenericF. gigantica, with thus far unknown implications. Over the fluke's extended range, in addition to domestic stock animals, wild native or naturalized mammals can also serve as final hosts. Indigenous and displaced populations ofF. hepatica, however, have not yet been studied comparatively from an evolutionary perspective.A. crassus, from the Far East, has invaded three continents, without the previous naturalization of its natural hostAnguilla japonica, by switching to the respective indigenous eel species. Local entomostrac crustaceans serve as susceptible intermediate hosts. The novel final hosts turned out to be naive in respect to the introduced nematode with far reaching consequences for the parasite's morphology (size), abundance and pathogenicity. Comparative infection experiments with Japanese and European eels yielded many differences in the hosts' immune defence, mirroring coevolution versus an abrupt host switch associated with the introduction of the helminth. In other associations of native hosts and invasive parasites, the elevated pathogenicity of the parasite seems to result from other deficiencies such as a lack of anti-parasitic behaviour of the naïve host compared to the donor host which displays distinct behavioural patterns, keeping the abundance of the parasite low. From the small amount of available literature, it can be concluded that the adaptation of certain populations of the novel host to the alien parasite takes several decades to a century or more. Summarizing all we know about hosts and parasites as aliens, tentative patterns and principles can be figured out, but individual case studies teach us that generalizations should be avoided.