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1.
Sci Total Environ ; 857(Pt 1): 159032, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36167133

RESUMO

Microcystin-leucine-arginine (MC-LR) adversely affects male reproduction and interferes with the development of the offspring. Here, we establish a zebrafish (Danio rerio) model to understand the cross-generational effects of MC-LR in a male-lineage transmission pattern. F0 embryos were reared in water containing MC-LR (0, 5, and 25 µg/L) for 90 days and the developmental indices of F1 and F2 embryos were then measured with no MC-LR treatment. The results show that paternal MC-LR exposure reduced the hatching rate, heart rate and body weight in F1 and F2 generations. Global DNA methylation significantly increased in sperm and testes with the elevation expressions of DNA methyltransferases. Meanwhile, DNA methylation of brain-derived neurotrophic factor (bdnf) promoter was increased in sperm after paternal MC-LR exposure. Subsequently, increased DNA methylation of bdnf promoter and decreased gene expression of bdnf in the brain of F1 male zebrafish were detected. F1 offspring born to F0 males exhibit the depression of BDNF/AKT/CREB pathway and recapitulate these paternal neurodevelopment phenotypes in F2 offspring. In addition, the DNA methylations of dio3b and gad1b promoters were decreased and gene expressions of gad1b and dio3b were increased, accompanied with neurotransmitter disturbances in the brain of F1 male zebrafish after paternal MC-LR exposure. These data revealed that MC-LR displays a potential epigenetic impact on the germ line, reprogramming the epigenetic and transcriptional regulation of brain development, and contributing to aberrant expression of neurodevelopment-related genes and behavior disorders.


Assuntos
Microcistinas , Peixe-Zebra , Animais , Masculino , Microcistinas/toxicidade , Leucina , Peixe-Zebra/fisiologia , Arginina , Fator Neurotrófico Derivado do Encéfalo , Sêmen , Epigênese Genética , Encéfalo , Expressão Gênica
2.
Sci Total Environ ; 858(Pt 2): 159838, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36343805

RESUMO

The dispersion of SARS-CoV-2 in aquatic environments via the discharge of domestic and hospital sewage has been confirmed in different locations. Thus, we aimed to evaluate the possible impacts of zebrafish (Danio rerio) exposure to SARS-CoV-2 peptide fragments (PSPD-2001, 2002, and 2003) alone and combined with a mix of emerging pollutants. Our data did not reveal the induction of behavioral, biometric, or mutagenic changes. But we noticed an organ-dependent biochemical response. While nitric oxide and malondialdehyde production in the brain, gills, and muscle did not differ between groups, superoxide dismutase activity was reduced in the "PSPD", "Mix", and "Mix+PSPD" groups. An increase in catalase activity and a reduction in DPPH radical scavenging activity were observed in the brains of animals exposed to the treatments. However, the "Mix+PSPD" group had a higher IBRv2 value, with NO levels (brain), the reduction of acetylcholinesterase activity (muscles), and the DPPH radical scavenging activity (brain and muscles), the most discriminant factors for this group. The principal component analysis (PCA) and hierarchical clustering analysis indicated a clear separation of the "Mix+PSPD" group from the others. Thus, we conclude that exposure to viral fragments, associated with the mix of pollutants, induced more significant toxicity in zebrafish adults than in others.


Assuntos
COVID-19 , Poluentes Ambientais , Poluentes Químicos da Água , Animais , Peixe-Zebra/fisiologia , SARS-CoV-2 , Acetilcolinesterase/metabolismo , Mutagênicos , Estresse Oxidativo , Poluentes Químicos da Água/toxicidade , Peptídeos , Biometria
3.
Behav Brain Res ; 436: 114115, 2023 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-36113727

RESUMO

Brain-derived neurotropic factor (BDNF) has established roles in neuronal survival and differentiation, in synaptic plasticity, and in neurotransmitters release. Several lines of evidence suggest that variations in BDNF might alter behaviour and contribute to neurobehavioural disorders. We investigated the functional effects of BDNF loss on behaviour by phenotyping a recently-generated CRISPR/Cas9 bdnf-/- zebrafish line through a battery of behavioural assays. Results of two behavioural tests suggested higher levels of locomotor activity in bdnf-/- zebrafish compared to bdnf+/+ zebrafish, in spite of similar swimming capacities observed in the two lines in a swim tunnel. bdnf-/- zebrafish also displayed higher levels of attraction towards a social stimulus compared to wild-type zebrafish, suggesting an effect of BDNF on sociability. Last, in a scototaxis test, we found evidence of potential differences in anxiety-like behaviour between the two lines. Our study supports an effect of BDNF on several behavioural traits, in line with early studies in mutant rodent models and in humans, suggesting the possibility to use the zebrafish to investigate diseases that involve alteration in BDNF levels.


Assuntos
Fator Neurotrófico Derivado do Encéfalo , Peixe-Zebra , Animais , Ansiedade , Comportamento Animal , Plasticidade Neuronal , Natação/fisiologia , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra
4.
Sci Total Environ ; 856(Pt 1): 158903, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36419276

RESUMO

The increase in temperature due to global warming greatly affects the toxicity produced by pesticides in the aquatic ecosystem. Studies investigating the effects of such environmental stress factors on next generations are important in terms of the sustainability of ecosystems. In this study, the effects of parental synergistic exposure to glyphosate and temperature increase on the next generation were investigated in a zebrafish model. For this purpose, adult zebrafish were exposed to 1 ppm and 5 ppm glyphosate for 96 h at four different temperatures (28.5, 29.0, 29.5, 30.0 °C). At the end of this period, some of the fish were subjected to the recovery process for 10 days. At the end of both treatments, a new generation was taken from the fish and morphological, physiological, molecular and behavioral analysis were performed on the offspring. According to the results, in parallel with the 0.5-degree temperature increase applied to the parents with glyphosate exposure, lower survival rate, delay in hatching, increased body malformations and lower blood flow and heart rate were detected in the offspring. In addition, according to the results of whole mouth larva staining, increased apoptosis, free oxygen radical formation and lipid accumulation were detected in the offspring. Moreover, it has been observed that the temperature increases to which the parents are exposed affects the light signal transmission and serotonin pathways in the offspring, resulting in more dark/light locomotor activity and increased thigmotaxis.


Assuntos
Aquecimento Global , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Ecossistema , Glicina/toxicidade
5.
Elife ; 112022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36317962

RESUMO

Unbiased genetic screens implicated a number of uncharacterized genes in hearing loss, suggesting some biological processes required for auditory function remain unexplored. Loss of Kiaa1024L/Minar2, a previously understudied gene, caused deafness in mice, but how it functioned in the hearing was unclear. Here, we show that disruption of kiaa1024L/minar2 causes hearing loss in the zebrafish. Defects in mechanotransduction, longer and thinner hair bundles, and enlarged apical lysosomes in hair cells are observed in the kiaa1024L/minar2 mutant. In cultured cells, Kiaa1024L/Minar2 is mainly localized to lysosomes, and its overexpression recruits cholesterol and increases cholesterol labeling. Strikingly, cholesterol is highly enriched in the hair bundle membrane, and loss of kiaa1024L/minar2 reduces cholesterol localization to the hair bundles. Lowering cholesterol levels aggravates, while increasing cholesterol levels rescues the hair cell defects in the kiaa1024L/minar2 mutant. Therefore, cholesterol plays an essential role in hair bundles, and Kiaa1024L/Minar2 regulates cholesterol distribution and homeostasis to ensure normal hearing.


Cholesterol is present in every cell of the body. While it is best known for its role in heart health, it also plays a major role in hearing, with changes in cholesterol levels negatively affecting this sense. To convert sound waves into electrical brain signals, specialised ear cells rely on hair-like structures which can move with vibrations; cholesterol is present within these hair 'bundles', but its exact role remains unknown. Genetic studies have identified over 120 genes essential for normal hearing. Animal data suggest there may be many more ­ including, potentially, some which control cholesterol. For instance, in mice, loss of the Minar2 gene causes profound deafness. Yet exactly which role the protein that Minar2 codes for plays in the ear remains unknown. This is in part because that protein does not resemble any other related proteins, making it difficult to infer its function. To find out more, Gao et al. investigated loss of minar2 in zebrafish, showing that deleting the gene induced deafness in the animals. Without minar2, the hair bundles in ear cells were longer, thinner, and less able to sense vibrations: cholesterol could not move into these structures, causing them to dysfunction. Exposing the animals to drugs that lower or raise cholesterol levels respectively worsened or improved their hearing abilities. A recent study revealed that mutations in MINAR2 also cause deafness in humans. The findings by Gao et al. highlight the need for further research which explores the role of cholesterol and MINAR2 in hair bundle function, as this may potentially uncover cholesterol-based treatments for hearing problems.


Assuntos
Perda Auditiva , Peixe-Zebra , Animais , Camundongos , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética , Mecanotransdução Celular/fisiologia , Audição/fisiologia , Perda Auditiva/genética , Colesterol
6.
Environ Toxicol Pharmacol ; 96: 104006, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36328330

RESUMO

The consumption of progestins has increased considerably in recent decades, as has their disposal into the environment. These substances can negatively affect the reproduction, physiology, and behavior of non-target organisms, such as fish. We aimed to evaluate the effects of exposure to environmentally relevant concentrations of levonorgestrel-control birth based (1.3, 13.3, 133, and 1330 ng/L) on the development and behavior of zebrafish (Danio rerio) in terms of mortality, hatching, spontaneous movement, and larval and adult behavioral tests. Exposure caused anxiogenic-like behavior in larvae, which persisted in adults, as demonstrated by the light-dark test. In contrast, it caused anxiolytic-like behavior in the novel tank test. There was a high mortality rate at all tested concentrations and increases in the hormone cortisol at 13.3 ng/L that affected the sex ratio. These changes may lead to an ecological imbalance, emphasizing the risk of early exposure to progestins in the environment.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Humanos , Animais , Feminino , Peixe-Zebra/fisiologia , Levanogestrel/toxicidade , Progestinas/toxicidade , Larva , Anticoncepcionais Orais Combinados/farmacologia , Anticoncepção , Poluentes Químicos da Água/toxicidade , Embrião não Mamífero
7.
Int J Mol Sci ; 23(22)2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36430778

RESUMO

Cisplatin is an effective anticancer agent, but also causes permanent hearing loss by damaging hair cells-the sensory receptors essential for hearing. There is an urgent clinical need to protect cochlear hair cells in patients undergoing cisplatin chemotherapy. The zebrafish lateral line organ contains hair cells and has been frequently used in studies to screen for otoprotective compounds. However, these studies have employed a wide range of cisplatin dosages and exposure times. We therefore performed a comprehensive evaluation of cisplatin ototoxicity in the zebrafish lateral line with the goal of producing a standardized, clinically relevant protocol for future studies. To define the dose- and time-response patterns of cisplatin-induced hair-cell death, we treated 6-day-old larvae for 2 h in 50 µM-1 mM cisplatin and allowed them to recover. We observed delayed hair cell death, which peaked at 4-8 h post-exposure. Cisplatin also activated a robust inflammatory response, as determined by macrophage recruitment and phagocytosis of hair cells. However, selective depletion of macrophages did not affect hair cell loss. We also examined the effect of cisplatin treatment on fish behavior and found that cisplatin-induced lateral line injury measurably impaired rheotaxis. Finally, we examined the function of remaining hair cells that appeared resistant to cisplatin treatment. We observed significantly reduced uptake of the cationic dye FM1-43 in these cells relative to untreated controls, indicating that surviving hair cells may be functionally impaired. Cumulatively, these results indicate that relatively brief exposures to cisplatin can produce hair cell damage and delayed hair cell death. Our observations provide guidance on standardizing methods for the use of the zebrafish model in studies of cisplatin ototoxicity.


Assuntos
Sistema da Linha Lateral , Ototoxicidade , Animais , Cisplatino/toxicidade , Peixe-Zebra/fisiologia , Larva
8.
Front Endocrinol (Lausanne) ; 13: 969481, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36387889

RESUMO

Efforts to understand the morphogenesis of complex craniofacial structures have largely focused on the role of chondrocytes and osteoblasts. Along with these bone-creating cells, bone-resorbing osteoclasts are critical in homeostasis of adult skeletal structures, but there is currently limited information on their role in the complex morphogenetic events of craniofacial development. Fundamental aspects of skull formation and general skeletal development are conserved from zebrafish to mammals. Using a cathepsinK reporter, we documented osteoclast location in the developing zebrafish skull over several weeks, from 5.18 mm to 9.6 mm standard length (approximately 15 to 34 days post fertilization). While broad distribution of osteoclasts is consistent across individuals, they are sparse and the exact locations vary among fish and across developmental time points. Interestingly, we observed osteoclasts concentrating at areas associated with neuromasts and their associated nerves, in particular the hyomandibular foramina and around the supraorbital lateral line. These are areas of active remodeling. In contrast, other areas of rapid bone growth, such as the osteogenic fronts of the frontal and parietal bones, show no particular concentration of osteoclasts, suggesting that they play a special role in shaping bone near neuromasts and nerves. In csf1ra mutants lacking functional osteoclasts, the morphology of the cranial bone was disrupted in both areas. The hyomandibular foramen is present in the initial cartilage template, but after the initiation of ossification, the diameter of the canal is significantly smaller in the absence of osteoclasts. The diameter of the supraorbital lateral line canals was also reduced in the mutants, as was the number of pores associated with neuromasts, which allow for the passage of associated nerves through the bone. Our findings define important and previously unappreciated roles for osteoclast activity in shaping craniofacial skeletal structures with a particular role in bone modeling around peripheral cranial nerves, providing a scaffold for wiring the sensioneural system during craniofacial development. This has important implications for the formation of the evolutionarily diverse lateral line system, as well understanding the mechanism of neurologic sequelae of congenital osteoclast dysfunction in human craniofacial development.


Assuntos
Osteoclastos , Peixe-Zebra , Animais , Humanos , Osteoclastos/fisiologia , Peixe-Zebra/fisiologia , Crânio , Cabeça , Desenvolvimento Ósseo , Mamíferos
9.
Physiol Behav ; 257: 113978, 2022 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-36183853

RESUMO

The effects of ethanol and caffeine exposure on zebrafish, Danio rerio, were investigated using a combination of measurements of behavioral and physiologic responses in a novel tank situation. Ventilation activity as a physiologic measure was measured remotely by monitoring ventilation-related bioelectric signals from freely moving zebrafish in the test tank. The directions of the behavioral responses, except for outer area preference, were substantially the same in both ethanol- and caffeine-treated fish and qualitatively indistinguishable, suggesting that relying solely on behavioral measures may lead to inappropriate interpretation of drug effects when depending on limited behavioral parameters. By incorporating ventilation activity-related physiologic measures into the quantification of drug effects in novel tank tests, more-accurate evaluations of differences in the effects of moderate doses of anxiolytic ethanol and anxiogenic caffeine were possible. Here, we propose that combining physiologic measures such as ventilation rate and its variability with behavioral measures makes it possible to characterize the effects of environmental challenges on zebrafish in a multi-dimensional and more-detailed manner.


Assuntos
Ansiolíticos , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Cafeína/farmacologia , Comportamento Animal/fisiologia , Ansiolíticos/farmacologia , Etanol/farmacologia , Ansiedade/tratamento farmacológico
10.
J Exp Biol ; 225(20)2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-36189492

RESUMO

Fishes use olfaction to gain varied information vital for survival and communication. To understand biodiversity in fishes, it is important to identify what receptors individual fish use to detect specific chemical compounds. However, studies of fish olfactory receptors and their ligands are still limited to a few model organisms represented primarily by zebrafish. Here, we tested the c-fos expression of olfactory sensory neurons (OSNs) in an East African cichlid, the most diversified teleost lineage, by in situ hybridization with a c-fos riboprobe. We confirmed that microvillous neurons contributed the most to the detection of amino acids, as in other fishes. Conversely, we found that ciliated neurons contributed the most to the detection of conjugated steroids, known as pheromone candidates. We also found that V2Rs, the major receptor type in microvillous neurons, exhibited differential responsiveness to amino acids, and further suggest that the cichlid-specific duplication of V2R led to ligand differentiation by demonstrating a differential response to arginine. Finally, we established a non-lethal method to collect cichlid urine and showed how various OSNs, including V1R+ neurons, respond to male urine. This study provides an experimental basis for understanding how cichlids encode natural odours, which ultimately provides insight into how olfaction has contributed to the diversification of cichlids.


Assuntos
Ciclídeos , Receptores Odorantes , Masculino , Animais , Odorantes , Receptores Odorantes/genética , Ciclídeos/genética , Peixe-Zebra/fisiologia , Ligantes , Mucosa Olfatória , Feromônios , Aminoácidos , Esteroides , Arginina
11.
Behav Processes ; 203: 104767, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36252852

RESUMO

Collective behavior is ubiquitous among fish, yet, its hows and whys are yet to be completely elucidated. It is known that several environmental factors can dramatically influence collective behavior, by eliciting behavioral adaptations in the individuals and altering physical pathways of social interactions in the group. Yet, empirical research has mostly focused on the quantification of the role of one factor at a time, with a paucity of studies designed to explore the multi-sensory basis of collective behavior. We investigated collective behavior of zebrafish (Danio rerio) pairs swimming in a water channel under combined manipulations of illumination (bright and dark) and flow conditions (absence and presence). The ability of the pair to orient and school increased in the presence of the flow and when fish were allowed to visually interact under bright illumination. Shoaling, instead, was only modulated by the illumination, so that fish swam at higher relative distances in the dark, irrespective of the flow. We also found evidence in favor of a modulatory effect of flow and illumination on the formation of the pair. Specifically, in the bright illumination, fish swam more side-by-side against a flow than in placid water; likewise, in the presence of a flow, they spent more time side-by-side in the bright illumination than in the dark. These findings point at a rich interplay between flow and illumination, whose alterations have profound effects on collective behavior.


Assuntos
Comportamento Animal , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Comportamento Animal/fisiologia , Iluminação , Natação/fisiologia , Comportamento Social
12.
Psychopharmacology (Berl) ; 239(12): 3833-3846, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36269378

RESUMO

RATIONALE: The use of novel psychoactive substances has been steadily increasing in recent years. Given the rapid emergence of new substances and their constantly changing chemical structure, it is necessary to develop an efficient and expeditious approach to examine the mechanisms underlying their pharmacological and toxicological effects. Zebrafish (Danio rerio) have become a popular experimental subject for drug screening due to their amenability to high-throughput approaches. OBJECTIVES: In this study, we used methamphetamine (METH) as an exemplary psychoactive substance to investigate its acute toxicity and possible underlying mechanisms in 5-day post-fertilization (5 dpf) zebrafish larvae. METHODS: Lethality and toxicity of different concentrations of METH were examined in 5-dpf zebrafish larvae using a 96-well plate format. RESULTS: METH induced lethality in zebrafish larvae in a dose-dependent manner, which was associated with initial sympathomimetic activation, followed by cardiotoxicity. This was evidenced by significant heart rate increases at low doses, followed by decreased cardiac function at high doses and later time points. Levels of ammonia in the excreted water were increased but decreased internally. There was also evidence of seizures. Co-administration of the glutamate AMPA receptor antagonist GYKI-52466 and the dopamine D2 receptor antagonist raclopride significantly attenuated METH-induced lethality, suggesting that this lethality may be mediated synergistically or independently by glutamatergic and dopaminergic systems. CONCLUSIONS: These experiments provide a baseline for the study of the toxicity of related amphetamine compounds in 5-dpf zebrafish as well as a new high-throughput approach for investigating the toxicities of rapidly emerging new psychoactive substances.


Assuntos
Metanfetamina , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Metanfetamina/farmacologia , Larva , Dopamina/farmacologia , Convulsões/induzido quimicamente , Antagonistas de Aminoácidos Excitatórios/farmacologia
13.
Sci Rep ; 12(1): 17649, 2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36271109

RESUMO

The zebrafish is widely used as a model in biological studies. In particular, the heart rate and cortisol levels of zebrafish are commonly measured to elucidate the pharmacological effects of chemical substances. Meanwhile, although ventilation is also an important physiological index reflecting emotion-like states, few studies have evaluated the effects of chemicals on ventilation in adult zebrafish. In this study, we assessed whether it is possible to evaluate the pharmacological effects elicited by caffeine in adult zebrafish under free-swimming conditions. We measured the ventilation in adult zebrafish exposed to multiple concentrations of caffeine under restraint and free-swimming conditions and evaluated the pharmacological effects of caffeine using linear mixed model analysis. In addition, results of electrocardiogram analysis and swimming speeds were compared with those in previous reports to ensure that an appropriate dose of caffeine was administered. Under restraint conditions, caffeine significantly decreased heart rate and increased ventilation in a concentration-dependent manner. Under free-swimming conditions, the ventilation rate significantly increased with increasing caffeine concentration. These results indicate that the pharmacological effects elicited by chemicals on ventilation can be evaluated in free-swimming zebrafish.


Assuntos
Cafeína , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Cafeína/farmacologia , Natação , Hidrocortisona/farmacologia , Respiração , Comportamento Animal
14.
Cell Rep ; 41(4): 111535, 2022 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-36288693

RESUMO

Mechanisms underlying spontaneous locomotor recovery after spinal cord injury (SCI) remain unclear. Using adult zebrafish with complete SCI, we show that V2a interneurons regrow their axon to bridge the lesioned spinal segments in a subclass-specific and chronological order. Early after SCI, reestablishment of a unitary high-rhythm locomotor circuit is driven merely by axon-regrown fast V2a interneurons. Later, the reestablished intraspinal de novo circuit is organized into a modular design by axon-regrown fast and slow V2a interneurons rostral to the lesion, selectively driving caudal fast V2a/motor neurons and slow V2a/motor neurons, respectively. This orderly circuitry reestablishment determines the stepwise restoration of locomotor repertoire and recapitulates developmental processes. This progress can be interrupted by ablation of calretinin, a fast module-related protein, and accelerated by physical training. These findings suggest that promotion of axon regrowth of propriospinal V2a interneurons and establishment of de novo intraspinal circuits underpin the effectiveness of physical training in patients after SCI.


Assuntos
Traumatismos da Medula Espinal , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Calbindina 2 , Locomoção/fisiologia , Interneurônios/fisiologia , Medula Espinal/fisiologia
15.
Int J Mol Sci ; 23(17)2022 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-36077569

RESUMO

The present study induced prolonged hyperglycemia (a hallmark symptom of Type 2 diabetes [T2DM]) in Danio rerio (zebrafish) for eight or twelve weeks. The goal of this research was to study cognitive decline as well as vision loss in hyperglycemic zebrafish. Fish were submerged in glucose for eight or twelve weeks, after which they were assessed with both a cognitive assay (three-chamber choice) and a visual assay (optomotor response (OMR)). Zebrafish were also studied during recovery from hyperglycemia. Here, fish were removed from the hyperglycemic environment for 4 weeks after either 4 or 8 weeks in glucose, and cognition and vision was again assessed. The 8- and 12-week cognitive results revealed that water-treated fish showed evidence of learning while glucose- and mannitol-treated fish did not within the three-day testing period. OMR results identified an osmotic effect with glucose-treated fish having significantly fewer positive rotations than water-treated fish but comparable rotations to mannitol-treated fish. The 8- and 12-week recovery results showed that 4 weeks was not enough time to fully recovery from the hyperglycemic insult sustained.


Assuntos
Disfunção Cognitiva , Diabetes Mellitus Tipo 2 , Hiperglicemia , Animais , Cognição , Disfunção Cognitiva/etiologia , Glucose , Hiperglicemia/complicações , Manitol/farmacologia , Água , Peixe-Zebra/fisiologia
16.
J Exp Biol ; 225(20)2022 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-36172880

RESUMO

Deoxygenation and warming affect adult fish physiology in all aquatic ecosystems, but how these stressors impact the energetics of sensitive developing stages is largely unknown. Addressing this knowledge gap, we investigated chronic and acute effects of two stressors (high temperature and hypoxia) in yolk-sac larval (48-168 hpf) zebrafish (Danio rerio) energy budgets measuring, oxygen consumption rate, growth rate (absolute and specific), % net conversion efficiency, net cost of growth and scaling relationships. Embryos and larvae were raised under four chronic treatments: (1) control (28°C and PO2 21 kPa, T28O21), (2) high temperature (31°C and PO2 21 kPa, T31O21), (3) hypoxia (28°C and PO2 11 kPa, T28TO11) and (4) high temperature and hypoxia (31°C and PO2 11 kPa, T31O11). From each chronic treatment, larvae were acutely exposed to the same combinations of stressors for 1 h in a respirometer. At hatching, larvae from chronic high temperature (T31O21 and T31O11) treatments were larger (higher dry mass and standard length) than controls (T28O21 and T28O11), but by the end of the yolk-sac stage, increased metabolic demands diverted energy away from growth, increasing net cost of growth and lowering % net conversion efficiency. Control metabolic scaling relationships were significant and differed from 0.75, but metabolic levels were lower in acute hypoxia and high temperature/hypoxia. Thus, high temperature dominated larval energetics, acting synergistically with hypoxia to increase cumulative energetic costs and making allostasis difficult compared with older stages.


Assuntos
Alostase , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Ecossistema , Larva/fisiologia , Hipóxia
17.
Wound Repair Regen ; 30(6): 665-680, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-36148505

RESUMO

The underlying mechanisms of appendage regeneration remain largely unknown and uncovering these mechanisms in capable organisms has far-reaching implications for potential treatments in humans. Recent studies implicate a requirement for metabolic reprogramming reminiscent of the Warburg effect during successful appendage and organ regeneration. As changes are thus predicted to be highly dynamic, methods permitting direct, real-time visualisation of metabolites at the tissue and organismal level would offer a significant advance in defining the influence of metabolism on regeneration and healing. We sought to examine whether glycolytic activity was altered during larval fin regeneration, utilising the genetically encoded biosensor, Laconic, enabling the spatiotemporal assessment of lactate levels in living zebrafish. We present evidence for a rapid increase in lactate levels within min following injury, with a role of aerobic glycolysis in actomyosin contraction and wound closure. We also find a second wave of lactate production, associated with overall larval tail regeneration. Chemical inhibition of glycolysis attenuates both the contraction of the wound and regrowth of tissue following tail amputation, suggesting aerobic glycolysis is necessary at two distinct stages of regeneration.


Assuntos
Cicatrização , Peixe-Zebra , Animais , Humanos , Peixe-Zebra/fisiologia , Larva , Cicatrização/fisiologia , Regeneração/fisiologia , Glicólise , Lactatos/farmacologia
18.
Aquat Toxicol ; 252: 106296, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36162203

RESUMO

Water pollution from commonly occurring contaminants (metals, xenobiotics, etc.) is a serious global problem. Copper is a commonly occurring water contaminant. A variety of physiological and biological methods have been developed to monitor water quality. The assessment of biological responses is an effective method for identifying the harmful effects of contaminants on ecosystems. Fish is a highly recommended animal model in water quality monitoring. Swimming consistency (firmness) and respiratory metabolism (oxygen consumption rate, carbon dioxide excretion rate and respiratory quotient) are essential for fish to maintain body homeostasis toward coping with environmental stress. We exposed zebrafish to different concentrations (Treatment I-0.1 mg/L and Treatment II-1.58 mg/L) of CuSO4. We have continuously quantified the strength of behavior (swimming consistency) and physiological (respiratory rates) biomarkers for ten days using an online monitoring system of swimming behavior and external respiration. Swimming consistency and respiratory rates of zebrafish (p<0.05) decreased in the CuSO4-treated groups compared to the control group. Avoidance behavior has led to an endpoint behavior at copperiedus. The time-delayed toxic effect has resulted in CuSO4 treatment groups. We checked for swimming consistency aberration on the artificial neural array, Self-organizing map (SOM). Circadian rhythms were influenced by prolonged exposure to CuSO4 toxicity. A concentration- and duration-dependent behavior anomaly was noted in this study. Swimming behavior and respiratory metabolism patterns are sensitive non-invasive stress biomarkers for water quality monitoring studies.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Animais , Peixe-Zebra/fisiologia , Cobre/toxicidade , Poluentes Químicos da Água/toxicidade , Ecossistema , Dióxido de Carbono/farmacologia , Comportamento Animal , Natação , Biomarcadores
19.
Elife ; 112022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36166290

RESUMO

Mixed electrical-chemical synapses potentially complicate electrophysiological interpretations of neuronal excitability and connectivity. Here, we disentangle the impact of mixed synapses within the spinal locomotor circuitry of larval zebrafish. We demonstrate that soma size is not linked to input resistance for interneurons, contrary to the biophysical predictions of the 'size principle' for motor neurons. Next, we show that time constants are faster, excitatory currents stronger, and mixed potentials larger in lower resistance neurons, linking mixed synapse density to resting excitability. Using a computational model, we verify the impact of weighted electrical synapses on membrane properties, synaptic integration and the low-pass filtering and distribution of coupling potentials. We conclude differences in mixed synapse density can contribute to excitability underestimations and connectivity overestimations. The contribution of mixed synaptic inputs to resting excitability helps explain 'violations' of the size principle, where neuron size, resistance and recruitment order are unrelated.


Assuntos
Medula Espinal , Peixe-Zebra , Animais , Interneurônios/fisiologia , Neurônios Motores/fisiologia , Medula Espinal/fisiologia , Sinapses/fisiologia , Peixe-Zebra/fisiologia
20.
Aquat Toxicol ; 251: 106294, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36116344

RESUMO

Bisphenol S (BPS) has been widely used as a substitute for bisphenol A in industrial manufacturing. However, the safety of BPS is controversial, and the mechanism by which BPS exerts cardiovascular toxicity remains unclear. In this study, zebrafish embryos, including wild-type zebrafish and transgenic (flk1:eGFP), (gata1:DsRed) and (cmlc2:eGFP) zebrafish at 2 h postfertilization (hpf), were exposed to BPS at concentrations of 1, 10 and 100 µg/L for 24, 48 and 72 h, respectively. The data showed that BPS accelerated the expansion of the common cardinal vein and inhibited lumen formation between 24 hpf and 72 hpf. Moreover, low-dose BPS disturbed cardiac muscle contraction by breaking the calcium balance in cardiac muscle cells according to the RNA-seq results. As a consequence, increased heart rate and irregular blood circulation were observed in the BPS treatment groups. This result suggested that BPS at environmental relevant concentrations caused cardiovascular toxicity during the development of zebrafish embryos, possibly being an important inducer of cardiovascular injury later in life. These findings provide insight into the rational and safe application of BPS.


Assuntos
Poluentes Químicos da Água , Peixe-Zebra , Animais , Cálcio , Fenóis , Sulfonas/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/fisiologia
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