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Ferreira, Rita Joana Rodrigues da Silva Rua. "Cilia motility studies in zebrafish embryos." Master's thesis, Faculdade de Ciências e Tecnologia, 2012. http://hdl.handle.net/10362/7984.
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A thesis submitted in fulfilment of the requirements for the degree of Masters in Molecular Genetics and BiomedicineMotile ciliary dysfunctions cause specific Ciliopathies that affect mainly the respiratory tract, fertilization and left-right body establishment. The embryonic organ where left-right decisions are first taken is called the organizer, a ciliated organ where a leftward cilia driven fluid-flow is generated. The organizer is named node in the mouse and Kupffer’s vesicle (KV) in zebrafish. The correct left-right axis formation is highly dependent on signaling pathways downstream of such directional fluid-flow. Motile cilia need to be coordinated and Ciliary Beat Frequency (CBF) is characteristic of different types of cilia depending on their function. Using zebrafish as a model, our group has been studying cilia length regulation and motility in wild-type and deltaD-/- mutant embryos. Recently, we showed that Notch signalling was directly involved in the control of cilia length in the KV cells given that the deltaD-/- mutant present shorter KV cilia. The goal of this project was to characterize the CBF of deltaD-/- KV cilia vs. wild-type cilia and reveal how potential differences in CBF impact on KV fluid flow, using spectral analysis associated with highspeed videomicroscopy. By decomposing and comparing the obtained CBF with Fast Fourier Transform, we identified two major populations of motile cilia in wild-type as well as in deltaD-/- mutant embryos. However, we found the CBF populations had differential relative contributions and different distributions between wild-type and mutant embryos. Furthermore, by measuring the velocity of native particles we studied the KV fluid-flow and concluded that the dispersion of the flow velocity was much wider in the deltaD-/- mutants. On the other hand, based on a gene expression study of motility genes downstream of DeltaD, we concluded that motility related genes (dnah7, rsph3 and foxj1a) were deregulated in the mutants. During this project we generated data that led to new hypotheses that will allow us to test the causality between the described correlations.
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Fierro, Jr Javier. "Glutamatergic Synapse Formation in Developing Zebrafish Embryos." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/18752.
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In order for a human being to process complex thought, cells within the brain must communicate with each other in a very precise manner. The mechanisms which underlie the development of these connections, however, are poorly understood and thus require a thorough investigation. In this dissertation, we attempt to identify components involved in stabilizing synaptic contacts and the mechanisms by which synaptic proteins are trafficked to newly forming contact sites. Interestingly, we also identify a gene involved in the formation of the myotome.
To identify proteins involved in stabilizing synaptic contacts, we characterized the function of 4.1B in developing zebrafish embryos. 4.1B is a scaffolding molecule involved in stabilizing protein complexes at sites of cell adhesion. We identified two 4.1B genes in the zebrafish genome, 4.1B-a and 4.1B-b, which are differentially expressed and have evolved divergent functions. 4.1B-a is expressed within the central nervous system, specifically within primary motor neurons. Knockdown studies show a reduction in the number of synapses and altered kinetics of touch evoked-responses, suggesting a role in synaptic stabilization. In contrast, 4.1B-b is primarily expressed in muscle cells. Knockdown of 4.1B-b results in severe muscle fiber disorganization as well as altered locomotor behaviors. Together, these data suggest the basic functions of 4.1B are evolutionarily conserved, with new roles described in the development of synapses and muscle fibers.
To determine the mechanisms that underlie protein recruitment to newly forming synapses, we examined the recruitment of three distinct transport packets in the zebrafish spinal cord. During presynaptic assembly, we found synaptic vesicle protein transport vesicles preceded piccolo-containing active zone precursor transport vesicles, which in turn preceded synapsin transport vesicles. We identified the last transport packet as a unique and independent mechanism for the recruitment of synapsin, a protein involved in regulating the reserve pool of synaptic vesicles. Importantly, we found cyclin-dependent kinase 5 regulated the late recruitment of synapsin transport packets to synapses, thus identifying kinases as a key signaling molecule in the formation of synaptic contacts. Together, this work provides new insight into the mechanisms that underlie synaptogenesis.
This dissertation includes both previously published and unpublished co-authored material.
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Patterson, Lucy Jane. "Specification of blood and endothelium in zebrafish embryos." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417180.
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Clay, Hilary. "Early host-pathogen interactions during mycobacterial infection of zebrafish embryos /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5033.
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Ali, Nadeem. "Teratology in zebrafish embryos : a tool for risk assessment /." Uppsala : Dept. of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/10665293.pdf.
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Ellingson, Elizabeth A. (Elizabeth Ann) 1979. "Simultaneous visual and electro-cardiogram measurements of zebrafish embryos." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/36105.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2001.Includes bibliographical references (p. 37).
An experimental study was performed to determine a simultaneous visual and electrocardiogram measurement of zebrafish embryos. One zebrafish embryo was placed between two electrodes and the electrical signal was amplified 100 times, then a computer recorded the data. The visual reading of the zebrafish heart rate was obtained by viewing the embryo under a microscope. A variety of approaches were investigated to determine the heart rate including amplification, noise filtering and data manipulation. Noise was a significant obstacle in determining the zebrafish embryo's heart rate. Therefore, the signal was smoothed, digitally filtered, and a system transfer function was determined to extract the heart rate from the noisy signal. After the data manipulation, the electrical signal appeared to correspond to the visual reading of the heart rate. Providing a simultaneous visual and electrical measurement of the heart rate can lead to a better understanding of cardiological genetic mutations. This method of measuring the heart rate can supply information on the strength and pattern of the heartbeat, and also detect irregularities in the beat, which could lead to further understanding of cardiological genetic mutations and other related health problems in the future.
by Elizabeth A. Ellingson.
S.B.
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Zhang, Tiantian. "Investigations into the cryopreservation of zebrafish (Brachydanio rerio) embryos." Thesis, University of Bedfordshire, 1994. http://hdl.handle.net/10547/622045.
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Cryopreservation of fish embryos was studied using zebrafish embryo as a model system. Cryoprotectant toxicity, chilling sensitivity and embryo membrane permeability were investigated with a view to developing optimum protocols for cryopreservation of the embryos using controlled slow cooling, non-freezing storage and vitrification. Methanol was found to be the most effective cryoprotectant for controlled slow cooling and non-freezing storage of zebrafish embryos with 11 %heart beat stage embryos surviving after controlled slow cooling to -25°C. Zebrafish embryos were found to be very chilling sensitive with early developmental stages being the most sensitive to chilling injury. Embryo developmental stages after closure of the blastopore (>12-h), especially post heart beat stages were much more resistant to cryoprotectant toxicity and chilling injury. Heart beat stage (27-h) embryos proved to be the best embryo developmental stage for controlled slow cooling and non-freezing storage. Dechorionated embryos are more sensitive to cryoprotectant toxicity and chilling injury. The sensitivity to chilling injury of zebrafish embryos limited the use of controlled slow cooling and non-freezing storage for long term cryopreservation. The attempts at cryopreservation of zebrafish embryos using vitrification produced no embryo survival, although up to 32 % embryos remained morphologically intact immediately after vitrification. Poor cryoprotectant permeation, dehydration and consequently ice formation within the egg are probably the main factors on effecting embryo survival. The results of zebrafish embryo permeability studies demonstrated that the chorion of the embryos was permeable to water and cryoprotectants, whilst the vitelline (plasma) membrane was an effective permeability barrier. The inability to achieve sufficient penetration of the vitelline membrane by cryoprotectants poses severe problems for long term cryopreservation, which need to be overcome, possibly by permeabilisation of the vitelline membrane, before successful cryopreservation can be achieved.
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Gündel, Ulrike. "Proteomics approach for toxicity assessment in Zebrafish (Danio rerio) embryos /." Leipzig : UFZ - Umweltforschungszentrum Leipzig-Halle GmbH in der Helmholtz-Gemeinschaft / Helmholtz Centre for Environmental Research, 2009. http://opac.nebis.ch/cgi-bin/showAbstract.pl?sys=000278302.
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Burkhardt, Markus. "Electron multiplying CCD – based detection in Fluorescence Correlation Spectroscopy and measurements in living zebrafish embryos." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-61021.
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Fluorescence correlation spectroscopy (FCS) is an ultra-sensitive optical technique to investigate the dynamic properties of ensembles of single fluorescent molecules in solution. It is in particular suited for measurements in biological samples. High sensitivity is obtained by employing confocal microscopy setups with diffraction limited small detection volumes, and by using single-photon sensitive detectors, for example avalanche photo diodes (APD). However, fluorescence signal is hence typically collected from a single focus position in the sample only, and several measurements at different positions have to be performed successively. To overcome the time-consuming successive FCS measurements, we introduce electron multiplying CCD (EMCCD) camera-based spatially resolved detection for FCS. With this new detection method, multiplexed FCS measurements become feasible. Towards this goal, we perform FCS measurements with two focal volumes. As an application, we demonstrate spatial cross-correlation measurements between the two detection volumes, which allow to measure calibration-free diffusion coefficients and direction-sensitive processes like molecular flow in microfluidic channels. FCS is furthermore applied to living zebrafish embryos, to investigate the concentration gradient of the morphogen fibroblast growth factor 8 (Fgf8). It is shown by one-focus APD-based and two-focus EMCCD-based FCS, that Fgf8 propagates largely by random diffusion through the extracellular space in developing tissue. The stable concentration gradient is shown to arise from the equilibrium between a local morphogen production and the sink function of the receiving cells by receptor-mediated removal from the extracellular space. The study shows the applicability of FCS to whole model organisms. Especially in such dynamically changing systems in vivo, the perspective of fast parallel FCS measurements is of great importance. In this work, we exemplify parallel, spatially resolved FCS by utilizing an EMCCD camera. The approach, however, can be easily adapted to any other class of two-dimensional array detector. Novel generations of array detectors might become available in the near future, so that multiplexed spatial FCS could then emerge as a standard extension to classical one-focus FCSFluoreszenz-Korrelations-Spektroskopie (FCS) ist eine hochempfindliche optische Methode, um die dynamischen Eigenschaften eines Ensembles von einzelnen, fluoreszierenden Molekülen in Lösung zu erforschen. Sie ist insbesondere geeignet für Messungen in biologischen Proben. Die hohe Empfindlichkeit wird erreicht durch Verwendung konfokaler Mikroskop-Aufbauten mit beugungsbegrenztem Detektionsvolumen, und durch Messung der Fluoreszenz mit Einzelphotonen-empfindlichen Detektoren, zum Beispiel Avalanche-Photodioden (APD). Dadurch wird das Fluoreszenzsignal allerdings nur von einer einzelnen Fokusposition in der Probe eingesammelt, und mehrfache Messungen an verschiedenen Positionen in der Probe müssen nacheinander durchgeführt werden. Um die zeitaufwendigen, aufeinanderfolgenden FCS-Einzelmessungen zu überwinden, entwickeln wir in dieser Arbeit Elektronenvervielfachungs-CCD (EMCCD) Kamera-basierte räumlich aufgelöste Detektion für FCS. Mit dieser neuartigen Detektionsmethode werden Multiplex-FCS Messungen möglich. Darauf abzielend führen wir FCS Messungen mit zwei Detektionsvolumina durch. Als Anwendung nutzen wir die räumliche Kreuzkorrelation zwischen dem Signal beider Fokalvolumina. Sie ermöglicht die kalibrationsfreie Bestimmung von Diffusionskoeffizienten und die Messung von gerichteter Bewegung, wie zum Beispiel laminarem Fluss in mikrostrukturierten Kanälen. FCS wird darüber hinaus angewendet auf Messungen in lebenden Zebrafischembryonen, um den Konzentrationsgradienten des Morphogens Fibroblasten-Wachstumsfaktor 8 (Fgf8) zu untersuchen. Mit Hilfe von APD-basierter ein-Fokus FCS und EMCCD-basierter zwei-Fokus FCS zeigen wir, dass Fgf8 hauptsächlich frei diffffundiert im extrazellulären Raum des sich entwickelnden Embryos. Der stabile Konzentrationsgradient entsteht durch ein Gleichgewicht von lokaler Morphogenproduktion und globalem Morphogenabbau durch Rezeptor vermittelte Entfernung aus dem extrazellulären Raum. Die Studie zeigt die Anwendbarkeit von FCS in ganzen Modell-Organismen. Gerade in diesen sich dynamisch ändernden Systemen in vivo ist die Perspektive schneller, paralleler FCS-Messungen von großer Bedeutung. In dieser Arbeit wird räumlich aufgelöste FCS am Beispiel einer EMCCD Kamera durchgeführt. Die Herangehensweise ist jedoch einfach übertragbar auf jede andere Art von zwei-dimensionalem Flächendetektor. Neuartige Flächendetektoren könnten in naher Zukunft verfügbar sein. Dann könnte räumlich aufgelöste Multiplex-FCS eine standardisierte Erweiterung zur klassischen ein-Fokus FCS werden
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Witzel, Sabine. "Local Wnt11 Signalling and its role in coordinating cell behaviour in zebrafish embryos." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2006. http://nbn-resolving.de/urn:nbn:de:swb:14-1162424627109-87779.
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Wnt11 is a key signalling molecule that regulates cell polarity/migration during vertebrate development and also promotes the invasive behaviour of adult cancer cells. It is therefore essential to understand the mechanisms by which Wnt11 signalling regulates cell behaviour. The process of vertebrate gastrulation provides an excellent developmental system to study Wnt11 function in vivo. It is known that Wnt11 mediates coordinated cell migration during gastrulation via the non-canonical Wnt pathway that shares several components with a the planar cell polarity pathway (PCP) in Drosophila. However, the mechanisms by which these PCP components facilitate Wnt11 function in vertebrates is still unclear. While in Drosophila, the asymmetric localization of PCP components is crucial for the establishment of cell polarity, no asymmetric localization of Wnt11 pathway components have so far been observed in vertebrates. To shed light on the cellular and molecular mechanisms underlying Wnt11 signalling, I developed an assay to visualize Wnt11 activity in vivo using live imaging of Wnt11 pathway components tagged to fluorescent proteins. This allowed me to determine the sub-cellular distribution of these components and to correlate the effect of Wnt11 activity with the behaviour of living embryonic cells. I found that Wnt11 locally accumulates together with its receptor Frizzled7 (Fz7) at sites of cell-cell contacts and locally recruits the intra-cellular signalling mediator Dishevelled (Dsh) to those sites. Monitoring these apparent Wnt11 signalling centres through time-lapse confocal microscopy revealed, that Wnt11 activity locally increases the persistency of cell-cell contacts. In addition, I found that the atypical cadherin Flamingo (Fmi) is required for this process. Fmi accumulates together with Wnt11/Fz7 at sites of cell-cell contact and locally increased cell adhesion, via a mechanism that appears to be independent of known downstream effectors of Wnt11 signalling such as RhoA and Rok2. This study indicates that Wnt11 locally interacts with Fmi and Fz7 to control cell-contact persistency and to facilitate coherent and coordinated cell migration. This provides a novel mechanism of non-canonical Wnt signalling in mediating cell behaviour, which is likely relevant to other developmental systems. (Die Druckexemplare enthalten jeweils eine CD-ROM als Anlagenteil: 50 MB: Movies - Nutzung: Referat Informationsvermittlung der SLUB)
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Lin, Huichao, and 林慧超. "Distinctive functions of methionine aminopeptidase II in embryonic hematopoiesis in zebrafish embryos." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43572297.
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Lin, Huichao. "Distinctive functions of methionine aminopeptidase II in embryonic hematopoiesis in zebrafish embryos." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43572297.
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Arabeyyat, Zeinab H. "Molecular level biological effects of silver and titania nanoparticles on zebrafish embryos." Thesis, University of Hull, 2016. http://hydra.hull.ac.uk/resources/hull:15442.
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Nanotechnology raises issues concerning the toxic impact of nanoparticles (NPs) in organisms and the environment. Nanoparticles have been defined as materials with dimensions that are equal to or less than 100 nm. It is important to develop early warning tools of NP-induced biological effects to be able to monitor and manage for any possible impacts. In the current study, two types of NPs have been selected based on their wide use: silver-NPs (AgNPs) and titanium dioxide-NPs (TiO2NPs). Early zebrafish (Danio rerio) embryos exposed in vitro to 4-nm and 10-nm AgNPs, and to silver ions alone, and TiO2NPs have been used to measure the expression level of selected target genes. A global transcriptomic approach employing Suppression Subtractive Hybridization (SSH) was used in parallel to identify novel genes that may be involved in the fish embryo response as a result of exposure to NPs. TiO2NPs coated with different layers of anionic (PSS) and cationic (PAH) polyelectrolytes were also used to measure viability, morphology, and the expression level of selected target genes. The results indicate that pathways expressed in response to NP exposure differ among both AgNPs and TiO2NPs, either due to the size, concentration, exposure time, exposure conditions, surface chemistry and surface charge of coatings of the NPs. The responses indicate that D. rerio embryos respond to NPs with not only an oxidative stress response, but with transcripts associated with fertility and metabolic functions such as membrane transport and mitochondrial metabolism. This information may be used to inform early warning biomarker development for environmental monitoring applications in future.
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Andrade, Thayres de Sousa. "Effects of environmental factors on the toxicity of pesticides to zebrafish embryos." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15137.
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Doutoramento em BiologiaDuring the last century mean global temperatures have been increasing. According to the predictions, the temperature change is expected to exceed 1.5ºC in this century and the warming is likely to continue. Freshwater ecosystems are among the most sensitive mainly due to changes in the hydrologic cycle and consequently changes in several physico-chemical parameters (e.g. pH, dissolved oxygen). Alterations in environmental parameters of freshwater systems are likely to affect distribution, morphology, physiology and richness of a wide range of species leading to important changes in ecosystem biodiversity and function. Moreover, they can also work as co-stressors in environments where organisms have already to cope with chemical contamination (such as pesticides), increasing the environmental risk due to potential interactions. Therefore, the objective of this work was to evaluate the effects of climate change related environmental parameters on the toxicity of pesticides to zebrafish embryos. The following environmental factors were studied: pH (3.0-12.0), dissolved oxygen level (0-8 mg/L) and UV radiation (0-500 mW/m2). The pesticides studied were the carbamate insecticide carbaryl and the benzimidazole fungicide carbendazim. Stressors were firstly tested separately in order to derive concentration- or intensity-response curves to further study the effects of binary combinations (environmental factors x pesticides) by applying mixture models. Characterization of zebrafish embryos response to environmental stress revealed that pH effects were fully established after 24 h of exposure and survival was only affected at pH values below 5 and above 10. Low oxygen levels also affected embryos development at concentrations below 4 mg/L (delay, heart rate decrease and edema), and at concentrations below 0.5 mg/L the survival was drastically reduced. Continuous exposure to UV radiation showed a strong time-dependent impact on embryos survival leading to 100% of mortality after 72 hours of exposure. The toxicity of pesticides carbaryl and carbendazim was characterized at several levels of biological organization including developmental, biochemical and behavioural allowing a mechanistic understanding of the effects and highlighting the usefulness of behavioural responses (locomotion) as a sensitive endpoint in ecotoxicology. Once the individual concentration response relationship of each stressor was established, a combined toxicity study was conducted to evaluate the effects of pH on the toxicity of carbaryl. We have shown that pH can modify the toxicity of the pesticide carbaryl. The conceptual model concentration addition allowed a precise prediction of the toxicity of the jointeffects of acid pH and carbaryl. Nevertheless, for alkaline condition both concepts failed in predicting the effects. Deviations to the model were however easy to explain as high pH values favour the hydrolysis of carbaryl with the consequent formation of the more toxic degradation product 1- naphtol. Although in the present study such explanatory process was easy to establish, for many other combinations the “interactive” nature is not so evident. In the context of the climate change few scenarios predict such increase in the pH of aquatic systems, however this was a first approach focused in the lethal effects only. In a second tier assessment effects at sublethal level would be sought and it is expectable that more subtle pH changes (more realistic in terms of climate changes scenarios) may have an effect at physiological and biochemical levels with possible long term consequences for the population fitness.
Durante o século passado, as temperaturas globais médias têm vindo a aumentar. De acordo com as previsões, a mudança de temperatura deverá ser superior a 1,5ºC neste século e o aquecimento é provável que continue. Os ecossistemas de água doce estão entre os mais sensíveis, principalmente devido às mudanças no ciclo hidrológico e, consequentemente, em diversos parâmetros físico-químicos (ex. pH, oxigénio dissolvido). Alterações nos parâmetros abióticos de ambientes de água doce irão provavelmente afectar a distribuição, morfologia, fisiologia e riqueza de uma ampla gama de espécies levando a mudanças importantes na biodiversidade e funcionamento do ecossistema. Para além disto, eles também podem atuar como co-estressores em ambientes onde os organismos já tem que lidar com contaminação química. Portanto, o objetivo deste trabalho foi avaliar os efeitos de parâmetros ambientais sobre a toxicidade dos pesticidas para embriões de peixe-zebra. Foram estudados os seguintes fatores ambientais: pH (3,0-12,0), nível de oxigénio dissolvido (0-8 mg/L) e radiação UV (0-500 mW/m2). Os pesticidas estudados foram o inseticida carbamato carbaril e o fungicida benzimidazólico carbendazim. Ambos os estressores (fatores ambientais e pesticidas) foram testados separadamente a fim de obter curvas dose-resposta para estudar mais profundamente os efeitos combinados de estressores ambientais e toxicidade química, aplicando modelos de mistura. A caracterização das respostas do peixe-zebra ao estresse ambiental mostrou que os efeitos do pH foram totalmente estabelecidas após 24 h de exposição e a sobrevivência foi só afetada a valores de pH abaixo de 5 e acima 10. Os níveis reduzidos de oxigénio também afetaram o desenvolvimento dos embriões em concentrações abaixo de 4 mg/L (atraso, redução dos batimentos cardíacos e edema) e em concentrações abaixo de 0.5 mg/L a sobrevivência foi drasticamente reduzida. A exposição contínua a radiações UV mostrou um forte efeito dependente do tempo na sobrevivência dos embriões levando a 100% de mortalidade no final do ensaio. A toxicidade dos pesticidas carbaril e carbendazim foi caracterizada em vários níveis de organização biológica, incluindo desenvolvimento, biomarcadores e comportamental, permitindo uma compreensão mecanicista dos efeitos e destacando a utilidade de respostas comportamentais (locomoção) como um parâmetro sensível em ecotoxicologia. Uma vez que as curvas dose resposta para cada estressor foram estabelecidas, um estudo de toxicidade combinado foi realizado para avaliar os efeitos do pH sobre a toxicidade do carbaril. Os resultados mostraram que o pH pode modificar a toxicidade do pesticida carbaryl. O modelo conceitual de adição da concentração permitiu uma previsão precisa da toxicidade dos efeitos conjuntos do pH ácido e carbaril. No entanto, para a condição alcalina ambos os conceitos falharam na previsão dos efeitos. Os desvios ao modelo foram no entanto fáceis de explicar uma vez que os valores de pH elevados favoreceram a hidrólise do carbaril com a consequente formação de um produto de degradação mais tóxico 1-naftol. Embora no presente estudo tal processo explicativo foi fácil de estabelecer, para muitas outras combinações de natureza "interativa" talvez esse processo não seja tão evidente. No contexto das alterações climáticas poucos cenários preveem um aumento tão elevado do pH de sistemas aquáticos, no entanto, esta pode ser considerada uma primeira abordagem focada apenas nos efeitos letais. Numa segunda avaliação, efeitos ao nível sub-letal seriam recomendados uma vez que espera-se que mudanças mais sutis de pH (mais realistas em termos de cenários de mudanças climáticas) possam ter um efeito em níveis fisiológicos e bioquímicos, com possíveis consequências a longo prazo para o fitness das populações.
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Chung, In-shing, and 鍾衍盛. "Characterization of sry-related HMG box group F genes in zebrafish hematopoiesis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B46332029.
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Strecker, Ruben [Verfasser], and Thomas [Akademischer Betreuer] Braunbeck. "Toxicity and teratogenesis in zebrafish embryos (Danio rerio) / Ruben Strecker ; Betreuer: Thomas Braunbeck." Heidelberg : Universitätsbibliothek Heidelberg, 2013. http://d-nb.info/1177148668/34.
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Sawle, Ashley David. "Gene expression profiles as indicators of ecotoxicological effect in zebrafish (Danio rerio) embryos." Thesis, University of Liverpool, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.494090.
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The development of DNA microarrays has provided a powerful new tool for investigating the gene expression changes that underlie response to toxicant exposure. The technology promised great improvements in understanding modes of action, the possibility of rapid toxicity screening of novel chemicals, and the potential for developing new methods of environmental monitoring. However, the technology has yet to truly deliver on these initial promises. Largely this can be attributed to the use of suboptimal experimental and statistical approaches. The aim of this study was to develop the application of gene expression profiling using microarrays to toxicity testing in the zebrafish embryo.
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Rabasco, Stefania. "Coumarin 47 and permethrin effects on zebrafish embryos: : FET tests and behavioural challenges." Thesis, Örebro universitet, Institutionen för naturvetenskap och teknik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-69075.
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An environment is defined as polluted when contaminants are introduced within it and causeadverse effects to its ecosystem. Chemical pollutants can migrate and often affect severalenvironmental compartments: for instance, chemicals can leach from polluted soil intogroundwater, or they can evaporate and disperse into the atmosphere.The recent advent of industrialisation and urbanisation has brought on the daily discharge ofharmful chemicals, such as heavy metals, organic pollutants and radioactive materials, into theenvironment via a high number of contamination sources, both commercial and industrial.More and more chemicals are identified as harmful to humans and the environment every year;in regard to the seemingly unsurmountable number of new ones being constantly introduced tothe market, it is important that authorities keep improving the efficiency of regulatoryprocedures and safety testing. This includes supporting scientific research which isfundamental for improving our understanding of the mechanisms of action of these chemicalsin order to handle them properly.In the present study, FET (Fish Embryo acute Toxicity) tests and behavioural challenges wereperformed on zebrafish (Danio rerio) embryos and larvae to investigate coumarin 47 andpermethrin in terms of toxicity and effect on larval photomotor response. A change inlocomotor activity in response to a light-to-dark transition stimulus is often the ultimate causeof exposure to specific neurotoxic agents, making it a useful endpoint in assessing centralnervous system toxicity, while FET tests are a guideline tool employed in the determination ofdevelopmental toxicity and teratogenicity.4Overall, the results obtained provided a significant understanding on the toxicity endpoints ofthe selected test compounds to be employed as references for future investigations.
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Plessy, Charles. "Control of neurogenin 1 expression in the anterior neural plate of zebrafish embryos." Université Louis Pasteur (Strasbourg) (1971-2008), 2003. http://www.theses.fr/2003STR13224.
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Pierce, Lain Xylia. "Analysis of Rhythmic Gene Transcription using the TimeR, a Novel Technology to Capture Zebrafish Embryos." Cleveland, Ohio : Case Western Reserve University, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1212770242.
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Desai, Kunjan. "Studies on the effect of chilling on sox genes and protein expression in zebrafish (Danio rerio) embryos." Thesis, University of Bedfordshire, 2012. http://hdl.handle.net/10547/271312.
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In aquaculture, short term chilled storage has been used to transport brood stock fish embryos for genetic improvement programmes. It is therefore important to understand the effect of chilling on embryos at both developmental and molecular levels. In the present study, gene expression patterns in zebrafish embryos were studied before investigations were carried out on the effect of chilling on gene and protein expression in these embryos. The gene expression results obtained in different developmental stages using conventional PCR showed that, only sox genes were expressed throughout the tested developmental stages from 30% epiboly to 6 somites. Quantitative RT-PCR was then used to investigate sox gene expression patterns during chilling of 50% epiboly stage embryos at 0°C for up to 180 min and also after warming. Significant decreases in sox2 and sox3 expressions were observed when compared to those of controls following chilling whilst significant increases of expressions of the two genes were observed after warming in the embryos chilled for 30 and 60 min. Studies on the impact of cryoprotectant MeOH on sox genes and protein expression showed that 50% epiboly stage zebrafish embryos could tolerate chilling for up to 6 h with or without MeOH. It was observed that expression of all three sox genes were significantly decreased following chilling for 3 h at 0°C. However the degree of decrease was less pronounced in embryos chilled with different concentrations of MeOH. Significant increases in sox genes were observed in hatching stage embryos chilled with 1 M MeOH for 3h but subsequent sox2 and sox19a protein expression was not affected. The effect of long term chilling (18h) on sox gene and protein expression in 50% epiboly stage embryos was also investigated. Improved hatching rates (56% ± 5) were achieved when embryos were chilled with 1 M MeOH + 0.1 M sucrose. Results from gene expression studies showed a stable sox2 gene expression in 18 h chilled embryos in cryoprotectant mixture when compared to that of embryos chilled without cryoprotectant mixture. Similar patterns were observed when the expression of sox2 and sox3 protein was investigated. This is the first study carried out on the effect of chilling in early stage zebrafish embryos at the molecular level. The results obtained from the present study provided useful information on the molecular mechanisms of the effect of chilling on zebrafish embryos and will have important implications in designing chilled storage protocols for fish embryos.
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Noche, Ramil Romare. "In Vivo Analysis of Zebrafish Exo-rhodopsin Protein and Suprachiasmatic Nucleus Function." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1212772912.
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Lawrence, Tim. "Body Length, Activity Level, and Avoidance Learning in Zebrafish Exposed to Nicotine as Embryos." TopSCHOLAR®, 2001. http://digitalcommons.wku.edu/theses/673.
Full textAbstract:
Smoking continues to be a significant health problem in the United States and throughout the world. One of the many aspects of the health risks of smoking that have been investigated is the effect of maternal smoking on developing embryos. In particular, exposure of embryos to nicotine is believed to cause attention-deficit/hyperactivity disorder (ADHD) and related problems in children. Both correlational research with humans and experimental research with animals have supported this belief. However, the mechanisms of the effect of nicotine on developing embryos are not fully understood. The zebrafish offers a useful model of the effects of nicotine on developing organisms because its development is fast, well understood, and easily observable. Also, the embryo can be exposed to nicotine without concern for many of the intermediate factors that are present in research with conventional models (e.g., the rat), such as the effect of nicotine on the placenta. This study was an exploratory attempt to establish the zebrafish as a model for the effects of embryonic nicotine (EN) exposure. Zebrafish eggs were exposed to two levels of nicotine during the first eight hours after fertilization. These subjects and a group of controls were measured on three variables at different stages of development: body length, activity level, and avoidance learning. Results showed that EN exposure caused a significant decrease in growth and a significant increase in activity level. Thus, the zebrafish responds to EN exposure in a manner similar to that observed in other models and in humans. Further research on the mechanisms of the effect of EN exposure may be possible using the zebrafish.
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Sempou, Aimilia [Verfasser]. "Molecular roles of the Prion Protein in zebrafish embryos and cultured cells / Aimilia Sempou." Konstanz : Bibliothek der Universität Konstanz, 2014. http://d-nb.info/1112478272/34.
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Murphy, Tami J. "Phenotypic analysis of transcriptional co-activator, brd2, gene knockdowns in zebrafish (Danio rerio) embryos." Click here for download, 2007. http://proquest.umi.com/pqdweb?did=1288659571&sid=1&Fmt=2&clientId=3260&RQT=309&VName=PQD.
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Jirari, Sara. "Functional Analysis of the Inner Nuclear Membrane Protein MAN1 in Zebrafish Adults and Embryos." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28685.
Full textAbstract:
ZMAN1 protein was identified in the brain, the gills, the liver, the kidney and the muscle tissue of the adult zebrafish. It is ubiquitously present in the brain and gill tissues. Using immunofluorescence on adult and embryonic cell lines, ZMAN1 was observed at the nuclear periphery. Moreover, cytoplasmic localization of ZMAN1 during mitotic phases indicates that ZMAN1 is not associated to mitotic chromosomes. ZMAN1 appeared at the surface of the new nuclear envelope at the beginning of nuclear reassembly. ZMAN1 distribution in blastula embryos was in the cytoplasm at different mitotic stages except for interphase, telophase and cytokinesis where it was targeted to the nuclear envelope. The maternally synthesized ZMAN1 was localized to the tail/posterior trunk of mid-pharyngula embryos and showed a very low expression and distribution patterns in the muscle tissue suggesting down-regulation of ZMAN1 at the adult stage. I also detected phenotypical abnormalities in ZMAN1 morphants, displayed a curved tail, dysfunctional tail vasculature and an enlarged pericadium, suggesting a possible function of ZMAN1 in blood vessels and heart morphogenesis. Altogether, my data suggest that ZMAN plays a role in early developmental processes and during the adult life of zebrafish.
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Al, Shaban Amani. "Developmental Toxicity of Ambroxol in Zebrafish Embryos/Larvae: Relevance of SULT-mediated Sulfation of Ambroxol." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1271349511.
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Brust, Kristin. "Toxicity of aliphatic amines on the embryos of zebrafish Danio rerio - experimental studies and QSAR." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2002. http://nbn-resolving.de/urn:nbn:de:swb:14-1028881472250-54161.
Full textAbstract:
The toxicity of 36 aliphatic amines on the embryos of the zebrafish Danio rerio were investigated. The DarT (Danio rerio Toxicity assay) was used to determine the lethal concentrations within a 48 h static acute toxicity test. A QSAR (Quantitative Structure-Activity Relationship) was performed using the LC50 values and molecular descriptors such as lipophilicity, maximum positive charge on hydrogen atom and the effective diameter of the molecule. In general, the toxicity of primary and secondary amines could be described by the lipophilicity as descriptor. The toxicity of the tertiary amines tested could be only described by a bilinear regression model. Further, regression models for other aquatic species such as the fathead minnow Pimephales promelas, Daphnia magna and Tetrahymena pyriformis showed that the toxicity of each species is a good predictor for each other.
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Cheng, Jackie Chong Nam. "A study of the roles of microfilaments and calcium transients during epiboly in zebrafish embryos /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202005%20CHENG.
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Lee, Karen Wing-man. "A study of the role of calcium ions during cytokinesis in cleavage stage zebrafish embryos /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202004%20LEE.
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Kwan, Tin-fu, and 關天富. "The role of zebrafish death receptor and survivin in embryonic hematopoiesis and angiogenesis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B35763280.
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Cheung, Yuk Kam. "The development of alternative methods to introduce the Ca2+-sensitive bioluminescent complex, aequorin, into zebrafish embryos /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202005%20CHEUNG.
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Lam, Pui Ying. "A study of the role of Ca2̳+̳ during early pronephros development in zebrafish (danio rerio) embryos /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202007%20LAM.
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Myers, Alexandra. "Identification of CaMK-II Protein Targets in Tissue Culture and Zebrafish Embryos using Tandem Mass Spectrometry." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/10.
Full textAbstract:
Calcium (Ca2+)/calmodulin-dependent kinase 2 (CaMK-II) is one member of a family of Ca2+/calmodulin-dependent protein kinases that responds to intracellular Ca2+ signals (Hudmon, A. and H. Schulman (2002)). CaMK-II is a multifunctional regulator of transcription, cell cycle progression, cell motility and neuronal development. (Wang, C., et al. (2008), Easley, C. A. IV, et al. (2008), Osterhoff, M., et al. (2003), Faison, M. O., et al. (2002)). Recently, CaMK-II has been shown to be important in the early development of vertebrates. In developing zebrafish, disruption of CaMK-II expression has been shown to induce phenotypes similar to those documented in several human diseases. The identification of the tissue-specific binding partners and substrates of CaMK-II which are responsible for specific developmental fates remains a key step in understanding this important protein kinase family. In this thesis research, specific “substrate-trapping” mutants of CaMK-II were designed, introduced into a variety of rodent and human cell lines in culture and used in conjunction with tandem mass spectrometry to identify binding partners, such as β-actin, tropomodulin-3 and Fli-I as well as novel, putative substrates, such as the tumor suppressor protein 53 (p53). This approach was subsequently applied to zebrafish embryos where an overlapping subset of CaMK-II binding proteins to those found in mammalian cell culture were identified. This project represents one of the first studies to identify binding proteins in zebrafish embryos using epitope tagging and mass spectrometry. This research has also established a technical framework for the use of mass spectrometry to characterize the developmental proteome of whole zebrafish embryos or specific zebrafish tissues at any developmental time point.
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Xu, Zheng. "Developmental Toxicity of Dextromethorphan and Acetaminophen in Zebrafish Embryos/Larvae: Relevance of SULT-mediated Dextromethorphan/Acetaminophen Sulfation." Toledo, Ohio : University of Toledo, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=toledo1271433014.
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Thesis (M.S.)--University of Toledo, 2010.Typescript. "Submitted to the Graduate Faculty as a partial fulfillment of the requirement for the Master of Science in Pharmacology and Toxicology." "A thesis entitled"--at head of title. Title from title page of PDF document. Bibliography: p. 68-81.
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Ahmed, Raju. "Investigation of the effects of different cryopreservation parameters on the genome of 51/4 hpf zebrafish (Danio rerio) embryos." Thesis, University of Bedfordshire, 2013. http://hdl.handle.net/10547/322165.
Full textAbstract:
In recent years, numerous studies have linked cryopreservation with increased occurrence of mutations, DNA fragmentation and the event of apoptosis in biological objects. However, the evidence emerged from such studies is somewhat inconclusive. The current study, therefore, aimed to analyse the DNA damage response (DDR) from the cryopreserved cells in order to characterise the nature of the putative DNA damage. The study set out to investigate the effects of different cryopreservation parameters on the genome in terms of double strand breaks (DSBs), single strand breaks (SSBs), and various forms of sequence alteration using 5¼ hour post fertilisation (hpf) zebrafish (Danio rerio) embryos. The experimental conditions under which the investigation was carried out were short term chilling at 0˚C, treatment with two cryoprotective agents (CPA), namely, MeOH and Me2SO, and cooling to -35˚C. Assays for detecting DSB-activated DDR proteins and SSB-activated DDR proteins in 5¼ hpf zebrafish (Danio rerio) were developed and then utilised to investigate the occurrence of DSBs and SSBs in the genome of the embryos treated with the experimental conditions. The study then analysed the expression profiles of a set of genes unique to the base excision repair (BER), nucleotide excision repair (NER) and mismatch repair (MMR) pathways as indicators of the occurrence of various forms of sequence alterations in the genome of the embryos treated with the experimental conditions. It was found that chilling and CPA treatment did not induce DSBs or SSBs but up-regulated the MMR and BER, respectively. CPA treatment also down-regulated the NER and the MMR mechanisms. Cooling, on the contrary, did not induce DSBs but induced SSBs in the genome, which were repaired when the embryos were provided with a recovery time. Cooling also up-regulated the NER and the BER mechanisms in the embryos. The overall finding of the study indicated that the experimental conditions increased the occurrence of various single stranded DNA lesions in the genome of the embryos. The present study provided important insights into how eukaryotic cells respond to different cryopreservation parameters, which will significantly enhance the current knowledge of the effects of cryopreservation on the genome of biological objects.
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Bountis, Stavros. "Effects of a phthalate mixture on Wnt/β-catenin signaling, apoptosis and metabolic rate in zebrafish embryos." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-415065.
Full textAbstract:
One of the most common plasticizers used in the production of plastic are phthalates. These chemicals have been associated with many adverse effects including developmental and reproductive anomalies. Early developmental processes targeted by chemicals can have long-lasting effects on individuals. The focus of this study was on investigating the effects of a phthalate monoester mixture on two evolutionarily conserved processes, Wnt/β-catenin signaling and apoptosis, both of which play an important role during development. Focus was also given on the mixture’s effect in metabolic rate. The phthalate mixture used is part of mixture G, a mixture which additionally contains triclosan and three perfluoroalkyl acids. The components of Mixture G were identified in a Swedish pregnancy cohort (SELMA) and were inversely associated with birth weight. The experiments were conducted in zebrafish embryos. Wnt signaling was analyzed in a transgenic zebrafish line, which had the EGFP gene linked to β-catenin regulated promoters, by measuring the fluorescence in the caudal fin. Apoptosis was analyzed through the acridine orange assay and metabolic rate through the transformation of resazurin to resorufin in presence of NADH/NADPH. The results showed a downregulation of Wnt signaling in zebrafish at two days post-fertilization (2 dpf), at a water concentration 100 times higher than the geometric mean serum concentration (100x hsc) of the mothers in the SELMA cohort. An upregulation of apoptosis was found at 1 dpf, at 60x hsc and 100x hsc. An effect on metabolic rate was observed at 100x hsc at 5 dpf. The results indicate that phthalates can disrupt Wnt signaling, induce apoptosis and influence metabolic rate, which along with the various reproductive effects they can induce warrants cause for concern not only for zebrafish embryos but for human fetuses as well.
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Saint-Amant, Louis. "Development of motor behaviors and activity patterns of spinal neurons in the zebrafish embryo." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=37628.
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The development of spinal circuits underlying motor behaviors was examined in zebrafish. Zebrafish embryos showed three sequential, stereotyped behaviors: a transient period of spontaneous coiling contractions, followed by touch-evoked rapid coils, and swimming. Lesioning the hindbrain eliminated swimming and touch responses, but not the spontaneous contractions.The first (spontaneous) behavior was chosen for further analysis in order to characterize the underlying circuit. In vivo patch clamp recordings were obtained from identified spinal neurons. These neurons showed periodic depolarizations that triggered rhythmic bursts of action potentials with a frequency and duration that were consistent with those of the spontaneous contractions. As with the behavior, transecting the spinal cord at the hindbrain border did not affect the rhythmic activity patterns of the neurons. Surprisingly the contractions and the periodic depolarizations were insensitive to both general and specific blockade of synaptic transmission. The periodic depolarizations were suppressed by heptanol and by intracellular acidification treatments that are known to uncouple gap junctions, indicating that electrotonic synapses could underlie network synchronization during the earliest motor behavior.
Paired recordings were obtained from identified spinal neurons. These showed that active ipsilateral neurons were electrically coupled in a simple network consisting initially of motoneurons and only three types of interneurons. Therefore, this early spinal circuit consists of rhythmically active and electrically coupled neurons. Furthermore, this circuit is also initially independent of the main neurotransmitter systems, sensory inputs, and descending hindbrain projections. The descending projections are required later in development for the onset of touch responses and swimming.
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Pan, Tien-chien, and 潘天健. "Calcium uptake mechanism in zebrafish embryos." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/28112065786570262313.
Full textAbstract:
碩士國立臺灣大學
漁業科學研究所
91
Vertebrates use Ca2+ as the major element for the formation of skeleton, which provides support and movement ability for individuals. In fish, water serves as a main source of Ca2+ than food, and gill has been proved to be the major Ca2+ uptake site that is responsible for more than 80% Ca2+ absorption. Ca2+ uptake occurs actively and also transcellularly through mitochondria-rich (MR) cells. The activities of plasma membrane Ca2+-ATPase (PMCA) and Na+-Ca2+ exchanger (NCX) have been identified in basolateral membrane of MR cells. PMCA and NCX have also been shown to be responsible for extruding Ca2+ into plasma. In the apical membrane, a Ca2+ channel is presumed to mediate Ca2+ entry, but there are no substantial molecular or physiological evidences for such channel in fish. The purpose of the present study is to identify the Ca2+ channel and elucidate its role in Ca2+ absorption. Zebrafish has been used extensively for the research of gene expression and developmental biology was selected as the model animal. In the present study, zebrafish ECaC (zECaC) from gill was cloned, sequenced, and the tissue distribution, developmental expression, and cellular localization of the zECaC were also studied. In addition, Ca2+ influx, Ca2+ content, and MR cell differentiation in different developmental stages of embryos were examined. The cloned zECaC is 2578 bp in legnth and encodes a protein of 709 amino acids. According to the phylogenetic analysis, trout and zebrafish ECaC were clustered together and formed a distinct group from amphibian and mammalian ones. It indicates that the duplication of ECaC may occur after the divergence of fish and mammals. zECaC was found to express ubiquitously in all the tissues examined, and started to express in embryos at 24 hours post fertilization (hpf). Ca2+ influx started to increase at 36 hpf while Ca2+ content accumulated after hatching. MR cells appeared on the embryos at 24 hpf, but first opening was observed at 36 hpf. According to the results, the timing of MR cell differentiation corresponded with the data of Ca2+ influx, and it implies a definite need for Ca2+ uptake from ambient environment during larval development. The zECaC expression pattern during development correlated with the first appearance of MR cell and also Ca2+ influx. Moreover, zECaC expression in gill was localized along the gill filaments where MR cells were concentrated. In conclusion, zECaC is first cloned in the present study, and it is expressed in all the tissues examined, including MR cells in gill. The wide tissue distributions suggest that zECaC may play a key role in Ca2+ absorption in developing embryo and also in adult fish.
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Aires, Ana Filipa Gomes. "Effects of cytostatic compounds on zebrafish embryos." Master's thesis, 2021. http://hdl.handle.net/10773/30788.
Full textAbstract:
Cytostatic drugs are a group of chemotherapeutic substances with different
mechanisms of action and with a significant increase of usage. These drugs,
mainly used in cancer treatment are, after their administration, excreted via the
urine and/or feces of the patients being treated, and further released into the
environment through hospital wastewater and/or domestic sewage. Due to the
inefficiency of wastewater treatment plants, these compounds reach the
environment affecting non-target animals, such as fish. Zebrafish is a biological
model widely used in the study the development of vertebrates, the modeling of
human diseases, such as cancer, and the evaluation of the effect of
environmental contaminants. Its use in many fields of research has been
increasing, given the advantages it presents in comparison to other traditional
models such as mice (e.g. ease of handling, laboratory maintenance and
genetic similarity with humans). This dissertation is divided into three chapters
which includes a general introduction, a review article and the experimental
work, and the principal aim of this work was to evaluate the physiological and
biochemical as well as behavioral responses provoked by two cytostatic
compounds, methotrexate and 5-fluorouracil, individually and in combination, in
zebrafish, after short exposures (120h) to a range of concentrations, including
environmentally relevant concentrations. Effects of both cytostatic compounds
were detected in the evaluated parameters. With methotrexate these
differences were detected predominantly at the highest concentration (1000
µg.L-1), while with 5-fluorouracil and the mixture there were differences in all
tested concentrations. Both drugs have been shown to cause stress in the
organisms and in general have caused changes in the heart level and tail of the
zebrafish. This work will shed some light for the understanding of the
consequences of the release of these compounds into the environment, to
identify more sensitive biological responses and potential mechanisms of
toxicity.Os compostos citostáticos são um grupo de substâncias quimioterapêuticas com diferentes mecanismos de ação cuja utilização tem tido um aumento significativo. Estes compostos, usados principalmente no tratamento do cancro são, após a sua administração, excretados via urina e/ou fezes dos pacientes em tratamento e posteriormente libertados para o ambiente através de efluentes hospitalares e/ou esgotos domésticos. Devido à ineficiência das estações de tratamento de águas residuais, estes compostos chegam ao ambiente afetando animais não alvo como, por exemplo, os peixes. O peixe zebra é um modelo biológico muito utilizado no estudo do desenvolvimento de vertebrados, modelação de doenças humanas como o cancro e avaliação do efeito de contaminantes ambientais. A sua utilização em muitos campos de investigação tem vindo a aumentar, dadas as vantagens que apresenta comparativamente a outros modelos tradicionais como por exemplo os ratinhos (e.g. facilidade de manipulação, manutenção laboratorial, similaridade genética com humanos). Esta dissertação está dividida em três capítulos onde inclui uma introdução geral, um artigo de revisão e o trabalho experimental, e teve como principal objetivo avaliar as respostas fisiológicas, bioquímicas e comportamentais provocadas por dois compostos citostáticos, metotrexato e 5-fluorouracilo, individualmente e em combinação, no peixe zebra, após exposições de curta duração (120h) a uma gama de concentrações, incluindo concentrações ambientalmente relevantes. Foram detetados efeitos de ambos os compostos citostáticos nos parâmetros avaliados. Com o metotrexato estas diferenças foram detetadas predominantemente na concentração mais elevada (1000 µg.L-1), enquanto com o 5-fluorouracil e com a mistura há diferenças em todas as concentrações testadas. Ambos os fármacos mostraram provocar stress nos organismos e de um modo geral provocaram alterações ao nível cardíaco e na cauda do peixe zebra. Este trabalho irá contribuir para a compreensão das consequências da libertação destes compostos para o ambiente, identificar respostas biológicas mais sensíveis e potenciais mecanismos de ação tóxica.
Mestrado em Bioquímica
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Ho, Chia-Yin, and 何佳穎. "Survivin/Birc5a and energy metabolism in zebrafish embryos." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/u7a3p2.
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Wu, Hui-Ju, and 吳蕙如. "Toxicity assessment of semiconductor wastewater using zebrafish embryos." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/67935626785527747172.
Full textAbstract:
碩士國立交通大學
環境工程系所
102
In semiconductor manufacturing processes nitrogenous substances are extensively used, resulting in production of very high nitrogen-containing wastewater. The high concentration of nitrogen-containing wastewater discharged to aquatic environment may cause eutrophication and toxicity. Although Taiwan EPA has regulated effluent standards for many pollutants, they are not sufficient to tell us if the discharge is toxic or not. Therefore, many countries are using animals to detect the toxicity of wastewater. Traditional toxicity tests usually use mortality as endpoint, but the sensitivity of this method is not adequate for low concentration pollutants. Zebrafish embryo assay has been regarded as a suitable alternative to the fish acute toxicity test which, apart from ethical reasons, provides very limited data (only LC50) and no ecotoxicological relevance. Due to transparency and extra-uterine development, zebrafish embryos can be directly observed the phenotypic changes during embryonic development. As a result, in this study zebrafish embryos were used to evaluate the toxicity and teratogenicity in nitrogen-containing wastewater. The purpose of this study is to examine the acute toxicity and developmental abnormalities in synthetic and real wastewater by using zebrafish embryos. The results show the 96h-LC50 of ammonium chloride, sodium nitrate and tetramethylammonium hydroxide were 111 mg NH3-N/L, 1347.3 mg NO3--N/L and 68 mg N/L, respectively; the low observed effect concentration were 0.41 mg NH3-N/L, 0.51 mg NO3--N/L及0.1 mg N/L, respectively. The endpoints such as hatching rate, heart rate and body length significantly declined in these three nitrogenous solutions. Abnormalities including spinal curvature, pericardial edema and yolk sac edema were also observed in sequence in zebrafish larvae. In real wastewater, the HF/CMP wastewater, acid-base wastewater and effluent from a semiconductor manufacturing factory were used. The mortality of zebrafish embryos in the acid-base wastewater and effluent was under 20% and 77% in HF/CMP wastewater in 96 hours. Although the mortality was low in the acid-base wastewater and effluent, the cumulative hatching rate, body length and especially heartbeat significantly decline. Abnormalities including spinal curvature, pericardial edema and yolk sac edema were also observed in real wastewater tests. The results indicate that the zebrafish embryos can be instrumental to detect the potential harm caused by wastewater on aquatic organisms at low concentrations. It suggests that embryo toxicity assay should be used to evaluate the toxicity of wastewater in the future.
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Liu, Fei-Lan, and 劉斐蘭. "Environmental Contamination and Expression of Stress Protein Zebrafish Embryos." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/08835352663345183517.
Full textAbstract:
碩士國立海洋大學
水產生物技術研究所
88
Abstract When cells are subjected to environmental stress conditions, they rapidly response to synthesize a suite of stress proteins, or referred as heat shock proteins (HSPs). These stress proteins are highly conserved from bacteria to human. Under stress conditions, a number of these stress proteins act as molecular chaperons that enable cells to survive in serious environmental conditions by preventing protein denaturing. In addition, some stress protein genes exhibit complex regulation pattern during embryogenesis in various vertebrate organisms. A number of environmental toxins have serious toxic effects in vertebrate development. To understand the molecular mechanism of these toxic effects in vertebrate development, expression patterns of hsp70 and hsp90 (hsp90α, hsp90β)genes in the pollutants-treated zebrafish embryos are examined. Fertilized fish embryos were treated by dioxin (2,3,7,8-TCDD), cadmium chloride, or xenoestrogen (nonylphenol-ethoxylate), and the transcription pattern of individual hsp genes was revealed by whole-mount RNA in situ hybridization analysis. We expect the results of these experiments will help us to understand the mechanism of vertebrate embryonic response to environmental stress conditions.
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Chen, Yi-Rong, and 陳意容. "The hypoxic signal and glycolytic metabolism in zebrafish embryos." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/02156406068632358533.
Full textAbstract:
碩士國立臺灣海洋大學
生命科學暨生物科技學系
103
Hypoxia inducible factors are the major regulators involved in hypoxia adaptation. In normoxic environment, hypoxia-inducible factors 1α and -2α are hydroxylated and ubiquitinated and subsequently degraded by proteosomes. Under hypoxic stress, these factors are stabilized and enter nucleus to activate a number of genes involved in angiogenesis, erythropoiesis, and anaerobic metabolism. The aerobic metabolism is also repressed by pyruvate dehydrogenase kinase (PDK) under hypoxic environment. Recent studies demonstrated that the proliferating stem cells and malignant cells display high level of anaerobic or aerobic glycolysis. Since HIF1α and -2α have critical roles in erythropoiesis and CNS development, respectively, it suggests these factors are presented in active form in neural and erythroid progenitor cells. By using tirapazamine which preferentially attacked the hypoxic cells, here I detected specific hypoxic signaling in the developing CNS neural cells and ICM erythroid progenitor cells at 24 hpf stages of zebrafish embryos. It may explain how HIFα proteins are kept in active form in neural and ICM cells. As analyzed by Hypoxyprobe-1 staining, there was no significant hypoxia signal detected in normal developing embryos. Nevertheless, continuous exposure to 2% oxygen concentration induced significant hypoxia signaling over the entire embryo, specifically in brain and vertebrate neurons. Apparently the Hypoxyprobe-1 is less sensitive to detect intracellular hypoxia stress than tirapazamine assay, but it responds to hypoxic extracellular microenvireonment more sensitive than tirapazamine. To investigate whether the local hypoxia microenvironment in the developing embryos induces anaerio metabolism, I have studied the expression patterns of various glycolytic genes in the developing embryos. It appears that most of glycolytic genes expressed in CNS regions. It consists with the results of hypoxia signaling in the developing embryos.
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Lin, Shuo-Peng, and 林碩芃. "Expression analysis of stathmin family genes in zebrafish embryos." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/99967651692715025439.
Full textAbstract:
碩士國立臺灣大學
生命科學系
104
Microtubules are well known to mediate many physiological processes in eukaryotic cell such as stable cell structure and axonal outgrowth. Microtubules can be regulated by different microtubule binding proteins to mediated their assembly and disassembly. Stathmin family proteins are phosphoprotein that regulates microtubules disassembly. Stathmin interacts with microtubules by binding to two moles of alpha and beta tubulin dimer to form a tetramer. Stathmins also interfere with microtubule polymerization by direct binding to microtubules. Via tight regulation of microtubule polymerization and depolymerization, stathmins are involved in different cellular processes, including neurogenesis, cell proliferation, differentiation and activities. In mammals, stmn 1 is ubiquitous expressed while other stathmin members, stmn 2, stmn 3, stmn 4 are mainly expressed in the nervous system. Previously, we have demonstrated that stmn 2, one of the zebrafish stathmin proteins, plays a vital role in zebrafish brain development. There are seven different stathmin genes in zebrafish. To understand the role of stathmin in zebrafish, I have cloned stmn 1a, stmn 2b and stmn 4l and demonstrated that they shared high identity with other vertebrate stathmin homologues. I analyzsed their temporal expression patterns using embryos at different stages by whole-mount in situ hybridization. I observed that stmn 1a and stmn 2b were expressed in spinal cord and trigeminal ganglia from 16 h post fertilization (hpf) but stmn 4l appeared from 18 hpf. stmn2b and stmn4l were mainly expressed in the central nervous system (CNS). Furthermore, the stmn1a transcripts were found in eyes, pharyngeal arches and tail bud. stmn 1a, stmn 2b and stmn4l were all expressed in hypothalamus, tegmentum, telencephalon and diencephalon after 24 hpf. After 48 hpf, stmn2b and stmn4l were still expressed in the CNS while stmn1a did not expressed in hindbrain. The dynamic expression of stathmin family genes in the developing central nervous system suggests a pivotal roles of those genes in regulating CNS development in zebrafish.
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KRISHNARAJ, PREETHI, and Preethi Krishnaraj. "Investigating the angiogenic effect of Dragon’s blood using zebrafish embryos." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/p4zss9.
Full textAbstract:
碩士慈濟大學
分子生物暨人類遺傳學系碩士班
106
Dragon’s blood which has a key angiogenic compound known as dracorhodin is widely used in Chinese traditional medicine to treat the wound. With the increasing popularity of Dragon’s blood in the traditional medical system, as well as a commercial product in the markets, there is a need in investigating a suitable source to obtain a fine quality Dragon’s blood. Presently, the only method to evaluate the quality of commercial Dragon’s blood samples is through HPLC method which determines the amount of dracorhodin in the Dragon’s blood sample. However, a feasible way to evaluate the in vivo Dragon’s blood activity is still lacking. In this study, I established a protocol to test the in vivo pro-angiogenic activity of Dragon’s blood by using zebrafish embryos with green fluorescence in the endothelial cells of the blood vessel. The results show that the commercial dragon’s blood samples although had been adjusted with similar amounts of dracorhodin, they still present a highly variable pro-angiogenic effect on the sub-intestinal veins development. This implies that the activity of dracorhodin could be modulated by other components in the Dragon’s Blood products of different sources. Now-a-days, at least three different plant species which produce red resin are used as sources of Dragon’s blood. However, whether all these plants contain the same active component for angiogenesis is not clear. Therefore, an in vivo platform could provide a chance to explore the novel active components of Dragon’s Blood by directly examing the angiogenic phenotypes. In conclusion, the protocol established in this thesis provides a rapid in vivo examination for the biological activity of commercial Dragon’s Blood which complements the current HPLC-based method.
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林致和. "Characterization of zebrafish thioredoxin (Trx) recombinate protein and resist chromium (Cr) induced oxidative damage to zebrafish embryos." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/32835769739766376871.
Full textAbstract:
碩士國立彰化師範大學
生物技術研究所
100
English Abstract Chromium (Cr) is released into the environment more than 100,000 tons per year after industrial usage. It has been shown to be toxic and carcinogenic both in vitro and in vivo, but little is known about its damage to aquatic embryos. In this study, we used zebrafish embryos as model to test Cr toxicity and its regulation on thioredoxin gene expression. The survival rate was 44% after 7.5mM Cr treatment for 12 h. Dose-dependent and time-course studies showed the LC50 was 7.5mM for 72h treatment. There are 16% teratogenesis were shown that included spinal column curving and edema in pericardial site. The reactive oxygen species were increased twofold and the lipid peroxidation was increased 2.5 fold after Cr treatment. Thioredoxin (Trx) is one of the important antioxidant enzymes in cell. The Trx gene expression was found major in notochord and head by whole-mount in situ hybridization. But the gene was inhibited up to 4 fold after Cr treatment for 6 h. We to observe survival rate was 46% that we knockdown Trx and There are 12% teratogenesis were shown that included spinal column curving and edema in pericardial site.The results showed Cr can inhibit Trx gene expression, and cause oxidative damage to fish embryos. We overexpression Trx to resist chromium (Cr) induced oxidative damage to zebrafish embryos Key word: chromium, ROS, Trx
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Dalle, Nogare Damian Edward. "Molecular-genetic analysis of cell cycle diversification in early zebrafish embryos." Thesis, 2008. http://hdl.handle.net/1911/22151.
Full textAbstract:
Modulation of basic cell-cycle parameters during development is necessary to ensure spatio-temporal diversity of cell cycle behaviour and impose specific cell cycle constraints during developmental processes. We have used the zebrafish, Danio rerio, to examine the molecular-genetic control of cell cycle diversification in early vertebrate embryos. We have cloned genes encoding four crucial regulators of cell cycle progression including two members of the cdc25 gene family and two of the wee gene family. Together, these genes modify the activity of the Cdk1 protein, a central component of the cell cycle regulatory mechanism. We show that these genes are dynamically expressed during early development, and that the action of one, cdc25a, is rate limiting for cell cycle progression in the early embryo. To further understand how the developmental program imposes constraints on cell cycle behaviour, we have investigated the mechanisms underlying acquisition of cell-cycle diversity at the first cell cycle transition, the midblastula transition (MBT). In zebrafish, and many other organisms, development begins with a rapid and synchronous cell division program with no gap phases between successive rounds of DNA synthesis and mitosis. This early cell cycle program is terminated at the MBT (cycle 10) when zygotic transcription is initiated and gap phases are first observed, resulting in cell cycle lengthening and desynchronization. We demonstrate that overexpression of cdc25a , but not cdc25d is sufficient to largely abolish cell cycle lengthening at the MBT, and that this can be recapitulated by injection of constitutively active cdk1AF, but not cdk2AF. Overexpression of wee1 mRNA causes precocious lengthening of pre-MBT cell cycles. Given the complex expression pattern of cdk phosphoregulators in zebrafish embryos, we hypothesize that Cdk phosphoregulation this may be a general mechanism for ensuring cell cycle diversity in the developing embryo.
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Wu, Chang-Hung, and 吳昌宏. "Improvement of a TEC Cryomicroscope and Freezing Experiments on Zebrafish Embryos." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/45906147083349163120.
Full textAbstract:
碩士國立臺灣大學
生物產業機電工程學研究所
93
The objectives of this research are to improve the design and performance of a TEC cryomicroscope, and to perform experiments on the observation of IIF behavior of zebrafish embryos. The cryomicroscope system includes a cryostage, a microscope with image grabbing system, a current amplifying circuit, and A/D signal processing system. The improvement mainly focused on the design of the cryostage. By using a glass well containing low freezing point liquid such as ethylene glycol, the original design was simplified and the problem of moisture condensation was avoided. The temperature control was accomplished using PID control algorithm. Following tuning PID parameters, the accuracy was improved. For constant temperature control in the range from 10℃ to −35℃, the maximum error was 0.45℃, and root-mean-squared-error was 0.34℃. A method was also implemented to avoid temperature overshoot when cooling process is approaching an isothermal process. For a cooling rate of −100℃/min, the overshoot was less than 0.40℃. The lowest temperature that the cryomicroscope can reach was dependent on the temperature of the refrigerated circulation bath. The lowest temperature achieved in this research was −49.6℃ while the highest cooling rate was −100℃/min. The cryomicroscope was used to observe IIF behavior of zebrafish embryos. Experimental results showed extra-embryonic ice nucleation can initiate intra-embryonic ice formation of zebrafish embryos. The pattern of extra-embryonic ice nucleation affects the probability of IIF of zebrafish embryos. Loading of cryoprotectants depressed the temperature and probabilities of IIF for zebrafish embryos loaded with glycerol and DMSO were determined and compared. IIF temperatures of zebrafish embryos were significantly lower when immersed in silicon oil. For embryos loaded with 2M DMSO and immersed in silicon oil, the IIF temperatures were −33.33±2.59℃ and −32.30±3.48℃ for epiboly and prim stage zebrafish embryos, respectively.
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Sun, Jhen-Jie, and 孫振傑. "Expression of zebrafish camsap genes in the embryos and adult tissues." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/57acx4.
Full textAbstract:
碩士國立高雄海洋科技大學
海洋生物技術研究所
102
CAMSAP, calmodulin regulated spectrin-associated protein, is a microtubule minus-end binding protein. In zebrafish, there are four camsap genes, camsap1a, camsap1b, camsap2 and camsap3. Mammalian CAMSAPs stablilize and regulate the polymerization of minus-end of noncentrosomal microtubule via a conserved CKK domain in their C-termini. The expression profiles and functions of camsap genes during embryonic development are unclear. In this study, the spatiotemporal expression patterns of zebrafish camsap genes were studied. We analyzed the nucleotide and amino acid sequences of four zebrafish camsaps and found that they all contain the conserved CKK domain in their C-termini and a variable region in the middle of proteins. RT-PCR analyses of adult tissues showed that camsap1a is expressed in the brain, camsap1b expressed in the muscle and testis, camsap2 expressed in the brain, muscle, testis and eyes, and camsap3 expressed in the muscle, ovary and testis. RT-PCR analyses of embryos at various stages showed that all four camsap genes are maternally expressed and deposited in the embryos at cleavage and blastula stages. Whole-mount in situ hybridization further revealed that the transcripts of all four camsap genes are initially maternally deposited in the cleavage and blastula embryos. The zygotic expressions of camsap genes start to differentiate from gastrula to hatching stages. Though camsap1a and camsap1b are all expressed in the midbrain, hindbrain, otic vesicles, retina, pectoral fins and yolk syncytial layer, the expression of camsap1b in the yolk syncytial nuclei and gut primordium is weaker. camsap2 and camsap3 are also expressed in the midbrain, hindbrain, otic vesicles, pectoral fins, and yolk syncytial layer, but the expression of camsap3 is lower in the retina and yolk syncytial layer.