Showing papers in "Zebrafish in 2017"
TL;DR: This study reappraises NTT and LDT for studying anxiety-like states in zebrafish, and emphasizes their developing utility for neurobehavioral research, which can help optimize drug screening procedures by choosing more appropriate models for testing anxiolytic or anxiogenic drugs.
Abstract: Modeling of stress and anxiety in adult zebrafish (Danio rerio) is increasingly utilized in neuroscience research and central nervous system (CNS) drug discovery. Representing the most commonly used zebrafish anxiety models, the novel tank test (NTT) focuses on zebrafish diving in response to potentially threatening stimuli, whereas the light-dark test (LDT) is based on fish scototaxis (innate preference for dark vs. bright areas). Here, we systematically evaluate the utility of these two tests, combining meta-analyses of published literature with comparative in vivo behavioral and whole-body endocrine (cortisol) testing. Overall, the NTT and LDT behaviors demonstrate a generally good cross-test correlation in vivo, whereas meta-analyses of published literature show that both tests have similar sensitivity to zebrafish anxiety-like states. Finally, NTT evokes higher levels of cortisol, likely representing a more stressful procedure than LDT. Collectively, our study reappraises NTT and LDT for studying anxiety-like states in zebrafish, and emphasizes their developing utility for neurobehavioral research. These findings can help optimize drug screening procedures by choosing more appropriate models for testing anxiolytic or anxiogenic drugs.
153 citations
TL;DR: The results suggest that the adult zebrafish behavioral model is a feasible alternative to more conventional laboratory models used in research on novel compounds with antinociceptive potential.
Abstract: The zebrafish (Danio rerio) has been proposed as a low-cost and simple alternative to the use of higher vertebrates in laboratory research on novel compounds with antinociceptive potential...
68 citations
TL;DR: The results suggest that UCMS increased anxiety-like behavioral responses, whereas developmental isolation altered motor responses during stimulus presentation, which reinforces the utility of combining developmental isolation with UCMS in zebrafish to model depressive-like behavior in humans.
Abstract: Unpredictable chronic mild stress (UCMS) and developmental social isolation are often utilized in laboratory animals to mimic unpredictable life stressors and early life adversity that may contribute to the development of major depressive disorder in humans. Zebrafish (Danio rerio) have been used to examine the effects of both developmental social isolation and UCMS. However, anxiety-like behavioral responses, social behavior, and neurochemical changes induced by stressors have not been well characterized. Furthermore, the possible interaction between UCMS and developmental isolation remains unexplored. In this study, we analyzed the effect of UCMS on developmentally isolated and socially reared zebrafish. The UCMS procedure entailed delivering unpredictably varying mild stressors twice a day for 15 consecutive days. To quantify social and anxiety-like behaviors, we measured the zebrafish's behavioral and neurochemical (dopaminergic and serotonergic) responses to an animated image of conspecifics in a novel tank. Our results suggest that UCMS increased anxiety-like behavioral responses, whereas developmental isolation altered motor responses during stimulus presentation. We also found that UCMS diminished weight gain and reduced whole-brain levels of dopamine and serotonin's metabolite 5-HIAA in developmentally isolated, but not socially reared zebrafish. Our findings reinforce the utility of combining developmental isolation with UCMS in zebrafish to model depressive-like behavior in humans.
67 citations
TL;DR: A Tol2 Gateway-compatible toolbox to study neurodegenerative disorders in zebrafish, which includes promoters for astrocytes, microglia and motor neurons, multiple fluorophores, and compatibility for the introduction of genes of interest or disease-linked genes is generated.
Abstract: Currently there is a lack in fundamental understanding of disease progression of most neurodegenerative diseases, and, therefore, treatments and preventative measures are limited. Consequently, there is a great need for adaptable, yet robust model systems to both investigate elementary disease mechanisms and discover effective therapeutics. We have generated a Tol2 Gateway-compatible toolbox to study neurodegenerative disorders in zebrafish, which includes promoters for astrocytes, microglia and motor neurons, multiple fluorophores, and compatibility for the introduction of genes of interest or disease-linked genes. This toolbox will advance the rapid and flexible generation of zebrafish models to discover the biology of the nervous system and the disease processes that lead to neurodegeneration.
54 citations
TL;DR: There is a substantial need for systematic analysis of these methods, that is, the effects of environmental factors on zebrafish health and breeding, and the question as to whether some degree of standardization is needed to enhance cross-laboratory comparability of results is discussed.
Abstract: In recent years, a rapidly increasing number of scientific papers have been published that utilize zebrafish (Danio rerio) as an alternative model organism in the study of a wide range of biological phenomena from cancer to behavior. This is, in large part, due to the prolific nature, relative ease of maintenance, and sufficiently high genetic homology of zebrafish to humans. With the surge of zebrafish use in animal research, the variations in methodologies of breeding and husbandry of this species have also increased. Investigators usually focus on the development and implementation of rigorous laboratory control that is specific to their studies. We suggest that the same scrutiny and attention may be required for the methods of breeding and housing of zebrafish. This article reviews a variety of zebrafish husbandry and breeding techniques and conditions employed around the world. It discusses factors ranging from numerous aspects of rearing/housing conditions through the sex ratio of the breeding group to the composition of the diet of zebrafish that may vary across laboratories. It provides some feedback on the potential pros and cons of the different methods. It argues that there is a substantial need for systematic analysis of these methods, that is, the effects of environmental factors on zebrafish health and breeding. It also discusses the question as to whether some degree of standardization of these methods is needed to enhance cross-laboratory comparability of results.
45 citations
TL;DR: The hypothesis that long-term social memory, previously described in mammals, is also present in zebrafish is supported, hence extending the evidence for the presence of this type of memory to teleost fish.
Abstract: In species in which individuals live in stable social groups, individual recognition is expected to evolve to allow individuals to remember past interactions with different individuals and adjust future behavior toward them accordingly. Thus, social memory is expected to be a ubiquitous component of social cognition of social species. However, few studies have investigated the occurrence of social memory in non-mammals. Here we evaluated the ability of zebrafish (Danio rerio) to recognize different conspecifics and to retain this information in long lasting (i.e. 24 h) memories. We used a social discrimination paradigm, adapted from mouse studies, in which the focal individual meets two pairs of conspecifics in two consecutive days: one conspecific is the same in both days and the other is different between days 1 and 2. If animals have the ability to discriminate between different conspecifics, it is predicted that they will spend more time exploring the novel than the familiar (i.e. already seen in day 1) conspecific. In this study, zebrafish with access to both olfactory and visual conspecific cues exhibited consistent recognition of a previously encountered (familiar) conspecific after a 24 h delay. This result supports the hypothesis that long-term social memory, previously described in mammals, is also present in zebrafish, hence extending the evidence for the presence of this type of memory to teleost fish.
44 citations
TL;DR: DMSO was toxic to rare minnow and zebrafish on multiple indexes, and the no-observed-effect concentrations of DMSO in both species were 1.0% and 0.001% for developmental toxicity analysis and stress protein analysis, respectively.
Abstract: Dimethyl sulfoxide (DMSO), a widely used carrier solvent, can be toxic to test organisms and has species-specific sensitivity. In this study, the developmental toxicity and stress protein responses of DMSO to rare minnow (Gobiocypris rarus) and zebrafish (Danio rerio) with two tests were compared in the early life stage. In the first test, fertilized eggs were exposed to 0%, 0.0001%, 0.001%, 0.01%, 0.1%, 1.0%, 1.5%, and 2.0% v/v of DMSO until 3 days post hatching. In the second test, larvae from 0 to 8 d were exposed to 2% DMSO until 4 days. Our results showed that DMSO was toxic to rare minnow and zebrafish on multiple indexes, and the no-observed-effect concentrations of DMSO in both species were 1.0% and 0.001% for developmental toxicity analysis and stress protein analysis, respectively. Furthermore, rare minnow larvae were more sensitive than zebrafish to DMSO for spinal malformation. The sensitive period for induction of spinal malformation by DMSO was 0–7 d after hatch (dah) for rare minno...
37 citations
TL;DR: The findings indicate that the zebrafish could be used as an effective screening tool during the discovery stages of new drugs to estimate their distribution in the brain.
Abstract: The objective of this study was to evaluate the permeability of small molecules into the brain via the blood–brain barrier in zebrafish and to investigate the possibility of using this animal model as a screening tool during the early stages of drug discovery. Fifteen compounds were used to understand the permeation into the brain in zebrafish and mice. The ratio of brain-to-plasma concentration was compared between the two animal models. The partition coefficient (Kp,brain), estimated using the concentration ratio at designated times (0.167, 0.25, 0.5, or 2 h) after oral administrations (per os, p.o), ranged from 0.099 to 5.68 in zebrafish and from 0.080 to 11.8 in mice. A correlation was observed between the Kp,brain values obtained from the zebrafish and mice, suggesting that zebrafish can be used to estimate Kp,brain to predict drug penetration in humans. Furthermore, in vivo transport experiments to understand the permeability glycoprotein (P-gp) transporter-mediated behavior of loperamide (...
34 citations
TL;DR: It is shown that swabbing, which may not require the use of anesthesia or analgesics, offers a reliable alternative to fin clipping, and is tested as a refinement to existing DNA sampling procedures.
Abstract: Fin clipping of live fish under anesthesia is widely used to collect samples for DNA extraction An alternative, potentially less invasive, approach involves obtaining samples by swabbing the skin of nonanesthetized fish However, this method has yet to be widely adopted for use in laboratory studies in the biological and biomedical sciences Here, we compare DNA samples from zebrafish Danio rerio and three-spined sticklebacks Gasterosteus aculeatus collected via fin clipping and skin swabbing techniques, and test a range of DNA extraction methods, including commercially available kits and a lower-cost, in-house method We verify the method for polymerase chain reaction analysis, and examine the potential risk of cross contamination between individual fish that are netted together We show that swabbing, which may not require the use of anesthesia or analgesics, offers a reliable alternative to fin clipping Further work is now required to determine the relative effects of fin clipping and swabbi
33 citations
TL;DR: This study is the first one presenting differential cytogenetic methods, such as C-banding, repetitive DNAs mapping, comparative genomic hybridization (CGH), and whole chromosome painting in lebiasinid species.
Abstract: Although fishes exhibit the greatest biodiversity among the vertebrates, a large percentage of this fauna is still underexplored on evolutionary cytogenetic questions, particularly the min...
32 citations
TL;DR: The variability in number of rDNA clusters, and the divergent syntenies for these three multigene families, put in evidence their evolutionary dynamism, revealing a much more complex organization of these genes than previously supposed for closely related species.
Abstract: Multigene families correspond to a group of genes tandemly repeated, showing enormous diversity in both number of units and genomic organization. In fishes, unlike rDNAs that have been well explored in cytogenetic studies, U2 small nuclear RNA (snRNA) genes are poorly investigated concerning their chromosomal localization. All Triportheus species (Characiformes, Triportheidae) studied so far carry a ZZ/ZW sex chromosomes system, where the W chromosome contains a huge 18S rDNA cistron. In some species the syntenic organization of rDNAs on autosomes was also verified. To explore this particular organization, we performed three-color-fluorescence in situ hybridization using 5S, 18S rDNA, and U2 snRNA genes as probes in eight Triportheus species. This work represents the first one analyzing the chromosomal distribution of U2 snRNA genes in genomes of Triportheidae. The variability in number of rDNA clusters, and the divergent syntenies for these three multigene families, put in evidence their evolutionary dynamism, revealing a much more complex organization of these genes than previously supposed for closely related species. Our study also provides additional data on the accumulation of repetitive sequences in the sex-specific chromosome. Besides, the chromosomal organization of U2 snDNAs among fish species is also reviewed.
TL;DR: A functionally compartmentalized device is engineered, the zebrafish Wounding and Entrapment Device for Growth and Imaging (zWEDGI), to orient larvae for high-resolution microscopy, including confocal and second harmonic generation (SHG), while allowing unrestrained tail development and regrowth.
Abstract: Zebrafish, an established model organism in developmental biology, is also a valuable tool for imaging wound healing in space and time with cellular resolution. However, long-term imaging of wound healing poses technical challenges as wound healing occurs over multiple temporal scales. The traditional strategy of larval encapsulation in agarose successfully limits sample movement but impedes larval development and tissue regrowth and is therefore not amenable to long-term imaging of wound healing. To overcome this challenge, we engineered a functionally compartmentalized device, the zebrafish Wounding and Entrapment Device for Growth and Imaging (zWEDGI), to orient larvae for high-resolution microscopy, including confocal and second harmonic generation (SHG), while allowing unrestrained tail development and regrowth. In this device, larval viability was maintained and tail regrowth was improved over embedding in agarose. The quality of tail fiber SHG images collected from larvae in the device was...
TL;DR: Behavioral responses are shaped by a complex interplay of extrinsic factors, such as predation and flow conditions, and intrinsic properties such as metabolic state, which influences choice and punishment.
Abstract: Behavioral responses are shaped by a complex interplay of extrinsic factors, such as predation and flow conditions, and intrinsic properties such as metabolic state. We investigated variations in boldness among four populations of zebrafish collected from widely varying habitat conditions across India. We measured feeding latencies of fish in four contexts: in a novel environment; in an environment with refuge and predators; in the presence of a shoal; and in the presence of a shoal and predators. The population from a high-flow and high-predation habitat was significantly bolder than populations from low-predation and low-flow/stagnant habitats. Individuals were significantly bolder in the presence of shoal and predators than in the other contexts. In general, males were significantly bolder than females. Smaller individuals took greater risks to feed than larger individuals only within two populations. The high-predation, high-flow habitat fish also showed significantly lower between- and within-individual variation in boldness than all the low-predation and low-flow populations. Furthermore, we found significantly repeatable responses across contexts within all populations, indicating behavioral consistency. Differences in response to variations in experimental contexts and stress and individual differences in metabolic rates could possibly explain the observed between- and within-individual variation among populations.
TL;DR: Sperm quality assessment using a combination of complementary endpoints enhances QC efforts during cryopreservation, increasing reliability and reproducibility, and reducing waste of time and resources.
Abstract: Quality control (QC) is essential for reproducible and efficient functioning of germplasm repositories. However, many biomedical fish models present significant QC challenges due to small body sizes (<5 cm) and miniscule sperm volumes (<5 μL). Using minimal volumes of sperm, we used Zebrafish to evaluate common QC endpoints as surrogates for fertilization success along sequential steps of cryopreservation. First, concentrations of calibration bead suspensions were evaluated with a Makler® counting chamber by using different sample volumes and mixing methods. For sperm analysis, samples were initially diluted at a 1:30 ratio with Hanks' balanced salt solution (HBSS). Motility was evaluated by using different ratios of sperm and activation medium, and membrane integrity was analyzed with flow cytometry at different concentrations. Concentration and sperm motility could be confidently estimated by using volumes as small as 1 μL, whereas membrane integrity required a minimum of 2 μL (at 1 × 106 cells...
TL;DR: It is shown that this simple method, which involves bulk polymerase chain reaction amplification and Sanger sequencing, is highly effective in tracking well-performing gRNAs in pools of genomic DNA derived from injected embryos.
Abstract: A bottleneck in CRISPR/Cas9 genome editing is variable efficiencies of in silico-designed gRNAs. We evaluated the sensitivity of the TIDE method (Tracking of Indels by DEcomposition) introduced by Brinkman et al. in 2014 for assessing the cutting efficiencies of gRNAs in zebrafish. We show that this simple method, which involves bulk polymerase chain reaction amplification and Sanger sequencing, is highly effective in tracking well-performing gRNAs in pools of genomic DNA derived from injected embryos. The method is equally effective for tracing INDELs in heterozygotes.
TL;DR: The functional role of fmr1 gene on the development of social behavior by behavioral experiments, including shoaling behavior, shoaling preference, light/dark test, and novel tank task, demonstrated that precocious development of Shoaling behavior is found in fmr2 KO zebrafish without affecting the shoaling preferences on conspecific zebra fish.
Abstract: Fragile X syndrome (FXS) is a generally hereditary form of human mental retardation that is caused by triplet repeat expansion (CGG) mutation in fragile X mental retardation 1 (fmr1) gene promoter and that results in the absence of the fragile X mental retardation protein (FMRP) expression. The common symptoms of FXS patients include learning disabilities, anxiety, autistic behaviors, as well as other behavioral abnormalities. Our previous results demonstrated the behavioral abnormalities in fmr1 knockout (KO) zebrafish such as fear memory impairment and autism-like behavior. Here, we studied the functional role of fmr1 gene on the development of social behavior by behavioral experiments, including shoaling behavior, shoaling preference, light/dark test, and novel tank task. Our results demonstrated that precocious development of shoaling behavior is found in fmr1 KO zebrafish without affecting the shoaling preference on conspecific zebrafish. The shoaling behavior appeared after 14 days postfertilization (dpf), and the level of shoaling elevated in fmr1 KO zebrafish. Furthermore, the fmr1 KO zebrafish at 28 dpf expressed higher anxiety level in novel tank task. These results suggest that the change of shoaling behavior in fmr1 KO zebrafish may result from hyperactivity and an increase of anxiety.
TL;DR: An international workshop was held in Karlsruhe, Germany, March 9, 2017, to identify methods that adequately address the physiology of zebrafish and its use as a biomedical research model, follow the principles of the 3Rs in animal experimentation and consider animal welfare during anesthesia and euthanasia.
Abstract: The increasing importance of zebrafish as a biomedical model organism is reflected by the steadily growing number of publications and laboratories working with this species. Regulatory recommendations for euthanasia as issued in Directive 2010/63/EU are, however, based on experience with fish species used for food production and do not take the small size and specific physiology of zebrafish into account. Consequently, the currently recommended methods of euthanasia in the Directive 2010/63/EU are either not applicable or may interfere with research goals. An international workshop was held in Karlsruhe, Germany, March 9, 2017, to discuss and propose alternative methods for euthanasia of zebrafish. The aim was to identify methods that adequately address the physiology of zebrafish and its use as a biomedical research model, follow the principles of the 3Rs (Replacement, Reduction, and Refinement) in animal experimentation and consider animal welfare during anesthesia and euthanasia. The results of the workshop are summarized here in the form of a white paper.
TL;DR: Characterizations of the first adult zebrafish model for FOP are presented and results suggest that transgenic zebra fish expressing heat-shock-inducible Acvr1lQ204D can serve as a model for human FOP.
Abstract: Fibrodysplasia ossificans progressiva (FOP) is a rare, autosomal dominant genetic disorder in humans characterized by explosive inflammatory response to injury leading to gradual ossification within fibrous tissues, including skeletal muscle, tendons, and ligaments. A variety of animal models are needed to study and understand the etiology of human FOP. To address this need, here we present characterizations of the first adult zebrafish model for FOP. In humans, activating mutations in the Type I BMP/TGFβ family member receptor, ACVR1, are associated with FOP. Zebrafish acvr1l, previously known as alk8, is the functional ortholog of human ACVR1, and has been studied extensively in the developing zebrafish embryo, where it plays a role in early dorsoventral patterning. Constitutively active and dominant negative mutations in zebrafish acvr1l cause early lethal defects. Therefore, to study roles for activating acvr1l mutations in adult zebrafish, we created transgenic animals expressing mCherry-tagged, heat-shock-inducible constitutively active Acvr1l, Acvr1lQ204D, to investigate phenotypes in juvenile and adult zebrafish. Our studies showed that adult zebrafish expressing heat-shock-induced Acvr1lQ204D develop a number of human FOP-like phenotypes, including heterotopic ossification lesions, spinal lordosis, vertebral fusions, and malformed pelvic fins. Together, these results suggest that transgenic zebrafish expressing heat-shock-inducible Acvr1lQ204D can serve as a model for human FOP.
TL;DR: Reactive oxygen species generation, antioxidant capacity against peroxyl radicals, and lipid peroxidation, as well as the activity and expression of the acetylcholinesterase (AChE) enzyme, were evaluated in Danio rerio males exposed to 5 or 10 mg/L of glyphosate for 24 and 96 h.
Abstract: It has been demonstrated that glyphosate-based herbicides are toxic to animals. In the present study, reactive oxygen species (ROS) generation, antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO), as well as the activity and expression of the acetylcholinesterase (AChE) enzyme, were evaluated in Danio rerio males exposed to 5 or 10 mg/L of glyphosate for 24 and 96 h. An increase in ACAP in gills after 24 h was observed in the animals exposed to 5 mg/L of glyphosate. A decrease in LPO was observed in brain tissue of animals exposed to 10 mg/L after 24 h, while an increase was observed in muscle after 96 h. No significant alterations were observed in ROS generation. AChE activity was not altered in muscles or brains of animals exposed to either glyphosate concentration for 24 or 96 h. However, gene expression of this enzyme in the brain was reduced after 24 h and was enhanced in both brain and muscle tissues after 96 h. Thus, contrary to previous findings that had att...
TL;DR: This study examines the effect of providing feed enriched with essential fatty acids, especially docosahexaenoic acid, to zebrafish spawners on fertility as well as the survival rate and growth of their offspring.
Abstract: The zebrafish is a freshwater fish of the Cyprinidae family, which is frequently used in scientific research. It owes its popularity to its genome, whose structure is comparable to the human genome and, for this reason, this species is often used in human medical research. However, such research requires high-quality material to conduct tests producing repeatable results. This study examines the effect of providing feed enriched with essential fatty acids, especially docosahexaenoic acid, to zebrafish spawners on fertility as well as the survival rate and growth of their offspring. The experiments revealed a significant (p < 0.05) effect of feeding spawners with feed enriched with polyunsaturated fatty acids on all tested parameters: their fertility (30% higher compared to the control group), survival rate, and the posthatching size of larvae, which were larger by 13% and 4%, respectively, compared to the control group.
TL;DR: It is shown that a combination of both MS-222 and isoflurane can significantly improve the anesthetic regime required for motionless image acquisition of live adult zebrafish, and this should lead to significant improvements in accuracy and information achievable from imaging live adultZebrafish and in its application to longitudinal studies.
Abstract: With many live imaging techniques, it is crucial that a deep level of anesthesia is reached and maintained throughout image acquisition without reducing zebrafish viability. This is particularly true for three-dimensional tomographic imaging modalities. Currently, the most commonly used anesthetic in the zebrafish community, MS-222 (tricaine methanesulfonate), does not allow this. We show, using a combination of both MS-222 and isoflurane, that we can significantly improve the anesthetic regime required for motionless image acquisition of live adult zebrafish. We have benchmarked this against the requirements of our novel quantitative imaging platform, compressive sensing optical projection tomography. Using nonpigmented transgenic zebrafish, we show that a combination of 175 ppm of both anesthetics improves the maintenance of deep anesthesia for prolonged periods of time and it can be used repeatedly to enable longitudinal imaging. Importantly, it does not affect the health or viability of the a...
TL;DR: Using mutant and transgenic zebrafish, it was found that every measured kinematic variable that distinguished larvae from adults also differentiated hypothyroid from wild-type (WT) euthyroid adults, suggesting that TH is indeed necessary for the onset of mature feeding behaviors.
Abstract: The physical demands for swimming and feeding change dramatically over the course of development for many aquatic animals. Indeed, in teleosts, the transition from larva to adult involves major shifts in both trophic morphology and feeding behavior. A spike in thyroid hormone (TH) coordinates many developmental processes that occur during this adult transition in numerous vertebrate species. Using mutant and transgenic zebrafish, we tested the hypothesis that TH is essential for the transition from larval to adult feeding kinematic profiles. We found that every measured kinematic variable that distinguished larvae from adults also differentiated hypothyroid from wild-type (WT) euthyroid adults, suggesting that TH is indeed necessary for the onset of mature feeding behaviors. In contrast, feeding kinematics in hyperthyroid adults were extremely similar to those measured in euthyroid adults. Altered TH signaling underlies pedomorphosis in some amphibian species, and Danionella is a pedomorphic danionin genus. We therefore tested whether feeding kinematics of adult Danionella would more closely match larval zebrafish (and hypothyroid adults) than WT adult zebrafish. We found Danionella feeding kinematics resemble those of larval (and hypothyroid) zebrafish in multiple respects. Overall, we conclude that TH is essential in stimulating the onset of adult feeding kinematics in zebrafish, and that some of the underlying developmental pathways may have been lost in Danionella.
TL;DR: A fully automated biological assay to test a standardized ototoxic dose of cisplatin against varying doses of compounds that protect or regenerate hair cells may facilitate rapid translation of candidate drugs into preclinical mammalian models of hearing loss.
Abstract: Zebrafish animal models lend themselves to behavioral assays that can facilitate rapid screening of ototoxic, otoprotective, and otoregenerative drugs Structurally similar to human inner ear hair cells, the mechanosensory hair cells on their lateral line allow the zebrafish to sense water flow and orient head-to-current in a behavior called rheotaxis This rheotaxis behavior deteriorates in a dose-dependent manner with increased exposure to the ototoxin cisplatin, thereby establishing itself as an excellent biomarker for anatomic damage to lateral line hair cells Building on work by our group and others, we have built a new, fully automated high-throughput behavioral assay system that uses automated image analysis techniques to quantify rheotaxis behavior This novel system consists of a custom-designed swimming apparatus and imaging system consisting of network-controlled Raspberry Pi microcomputers capturing infrared video Automated analysis techniques detect individual zebrafish, compute their orientation, and quantify the rheotaxis behavior of a zebrafish test population, producing a powerful, high-throughput behavioral assay Using our fully automated biological assay to test a standardized ototoxic dose of cisplatin against varying doses of compounds that protect or regenerate hair cells may facilitate rapid translation of candidate drugs into preclinical mammalian models of hearing loss
TL;DR: The zebrafish (Danio rerio) is a versatile model organism that has been used in biomedical research for several decades to study a wide range of biological phenomena and is one of the predominant models of human genetic diseases.
Abstract: The zebrafish (Danio rerio) is a versatile model organism that has been used in biomedical research for several decades to study a wide range of biological phenomena. There are many technical advantages of using zebrafish over other vertebrate models. They are readily available, hardy, easy, and inexpensive to maintain in the laboratory, have a short life cycle, and have excellent fecundity. Due to its optical clarity and reproducible capabilities, it has become one of the predominant models of human genetic diseases. Zebrafish research has made rapid strides in the United States and Europe, but in India the field is at an early stage and many researchers still remain unaware of the full research potential of this tiny fish. The zebrafish model system was introduced into India in the early 2000s. Up to now, more than 200 scientific referred articles have been published by Indian researchers. This review gives an overview of the current state of knowledge for zebrafish research in India, with the aim of promoting wider utilization of zebrafish for high level biological studies.
TL;DR: Cytogenetic data showed distinct karyotype organization among Rineloricaria populations/species studied, ranging in diploid number from 46 to 64 chromosomes, syntopic species and two karyomorphs in R Sentineloricaria pentamaculata.
Abstract: Cytogenetic studies in fish of the Rineloricaria genus have already shown a high variation in diploid number (2n). Along with fusion/fission events for 2n alteration, inversions contribute to the diversification of chromosome formulae within this group. The present study assessed different populations/species of the Rineloricaria aiming to describe the karyotype organization of its members and understand the mechanisms that lead to the variation of chromosome numbers. Cytogenetic data showed distinct karyotype organization among Rineloricaria populations/species studied, ranging in diploid number from 46 to 64 chromosomes, syntopic species and two karyomorphs in Rineloricaria pentamaculata. Using ribosomal DNAs (rDNAs) and TTAGGGn probes by fluorescence in situ hybridization in species with low diploid numbers, we detected sites of 18S rDNA, 5S rDNA, and TTAGGGn in centromeric regions of metacentric chromosomes, which participated in chromosome rearrangements like centric fusions. In species with...
TL;DR: This study analyzed, by classical and molecular cytogenetics methodologies, the chromosomal diversity of this genus, to discuss the processes that are involved in the evolution and karyotype differentiation of the species of the group.
Abstract: Most species of the genus Harttia inhabits the headwaters of small tributaries, but some species are restricted to the main channel of some rivers. This feature, combined with limited dispersal ability, leads to the formation of small isolated populations with reduced gene flow. Currently, there are 23 taxonomically defined and recognized species, and 17 of these are found in Brazil, distributed in several hydrographic basins. Despite this diversity, few chromosomal data for the species belonging to this genus are found in the literature. Thus, this study analyzed, by classical and molecular cytogenetics methodologies, the chromosomal diversity of this genus, to discuss the processes that are involved in the evolution and karyotype differentiation of the species of the group. Seven species of Harttia were analyzed: H. kronei, H. longipinna, H. gracilis, H. punctata, H. loricariformis, H. torrenticola, and H. carvalhoi. The chromosomal diversity found in these species includes different diploid and fundamental numbers, distinct distribution of several repetitive sequences, the presence of supernumerary chromosomes in H. longipinna and multiple sex chromosome systems of the type XX/XY1Y2 in H. carvalhoi and X1X1X2X2/X1X2Y in H. punctata. Lastly, our data highlight the genus Harttia as an excellent model for evolutionary studies.
TL;DR: The accumulation of nitrogen compounds represents a pivotal problem in the management of fish culture and several methods were investigated in the last decades for treatment of waste waters, but none of them satisfactorily addressed this problem.
Abstract: The accumulation of nitrogen compounds represents a pivotal problem in the management of fish culture. Several methods were investigated in the last decades for treatment of waste waters, ...
TL;DR: As glial cells are associated with most, if not all, synapses, Tg(gfap:iGluSnFR) is a novel and exciting tool to measure neuronal activity and extracellular glutamate dynamics in many regions of the nervous system.
Abstract: Glutamate is the major excitatory neurotransmitter in the brain. Its release and eventual recycling are key to rapid sustained neural activity. We have paired the gfap promoter region with the glutamate reporter molecule, iGluSnFR, to drive expression in glial cells throughout the nervous system. Tg(gfap:iGluSnFR) is expressed on the glial membrane of Muller glia cells in the retina, which rapidly respond to stimulation and the release of extracellular glutamate. As glial cells are associated with most, if not all, synapses, Tg(gfap:iGluSnFR) is a novel and exciting tool to measure neuronal activity and extracellular glutamate dynamics in many regions of the nervous system.
TL;DR: This work has developed a simple clearing and imaging pipeline optimally suited for the adult zebrafish brain to investigate changes in patterns of cell proliferation in wild-type and transgenic backgrounds that can easily be quantified and represented using FIJI and IMARIS software.
Abstract: How distinct cell populations are distributed in three-dimensional space under homeostasis or following injury, neurodegeneration, or with senescence can teach us much about brain-wide patterns and signaling along the neuroaxis. Visualizing individual cell populations in the mature vertebrate central nervous system (CNS) has remained a challenge as a result of difficulty clearing adult brain tissue or limitations in imaging depth or resolution. We have developed a simple clearing and imaging pipeline optimally suited for the adult zebrafish brain to investigate changes in patterns of cell proliferation in wild-type and transgenic backgrounds that can easily be quantified and represented using FIJI and IMARIS software.
TL;DR: Melatonin is confirmed for the first time the efficacy of melatonin in restoring parkinsonian phenotypes in animals and reflects changes in mitochondrial bioenergetics more precisely than in vitro mitochondrial preparations.
Abstract: Although mitochondria dysfunction is related to multiple diseases, no in vivo studies are available on mitochondrial respiration in animal parkinsonian models. Our aim is to analyze in vivo mitochondrial respiration, which reflects changes in mitochondrial bioenergetics more precisely than in vitro mitochondrial preparations. These experiments can be carried out in zebrafish embryos, which were treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) from 24 to 72 hours postfertilization (hpf). A reduction in electron transfer system capacity, ATP turnover, and increased proton leak were observed at 72 hpf in MPTP-treated embryos. These changes were followed by a significant oxidative stress due to inhibition in antioxidative defense and autophagy impairment. After removing MPTP from the treatment at 72 hpf, these bioenergetic deficiencies persisted up to 120 hpf. The administration of melatonin to zebrafish embryos at 72 hpf, when mitochondrial dysfunction is already present, restored th...