Aetiology of skeletal deformities in the Zebra Danio fish (Bruchydanio rerio, Hamilton-Buchanan)

Laboratory bred Zebra Danio ( Brachydanio rerio , Hamilton-Buchanan) tropical fish are prone to skeletal deformities resembling scoliosis and lordosis. This condition appears related to diet and has been studied by breeding from different broods of fish for three generations. Two broods bred using two commercially available tropical flaked foods developed severe spinal curvature three to six weeks post-hatching. A third brood of fish fed exclusively on live food did not develop any deformity. The results demonstrate that a dietary factor is responsible for the deformities and that the Zebra Danio is especially susceptible to this factor as other species breed normally when fed the same commercial diet. Analysis of the diets showed no deficiency in either ascorbic acid (Vitamin C) or tryptophan, deficiency of either being associated with scoliosis and lordosis in fish. The analysis did show, however, a relationship between the lead content of the diet and the incidence of deformities. Lead has previously been implicated in skeletal deformities in second and third generation Brook trout, Salvelinus fontinalis.     

Breeding the convict cichlid (Cichlasoma nigrofasciatum) for use in laboratory fish toxicity tests

A procedure is described for breeding Convict Cichlid ( Cichlasoma nigrofasciatum ) tropical fish under laboratory conditions. Three generations of Convict Cichlids were bred successfully using this procedure and there was no significant incidence of deformities from in–breeding to the F₃ , which contrasts with a high incidence of skeletal deformities observed when Zebra Danio tropical fish were inbred to the F ₃ generation. The Convict Cichlid is a suitable species for laboratory toxicity testing, particularly studies to assess effects on breeding performance.     

苯、二甲苯和苯酚中毒对Zebra鱼低水平化学发光的影响

Zebra鱼是研究生物系统低水平化学发光的很好材料.实验测定了苯、二甲苯及苯酚的浓度与Zebra鱼发光的相关性.结果表明:当三种毒物的注入量为16-20微升时,发光呈现高值并伴有死鱼现象.将一次有效剂量的苯、二甲苯及苯酚加入时,鱼会丧失游动能力直至死亡,且伴随着鱼体光子辐射的明显变化.谱分布表明,鱼的发光为单线态(~1O_2)的双分子同时跃迁.     

A comparative study of the sulfation of bile acids and a bile alcohol by the Zebra danio (Danio rerio) and human cytosolic sulfotransferases (SULTs)

The current study was designed to examine the sulfation of bile acids and bile alcohols by the Zebra danio (Danio rerio) SULTs in comparison with human SULTs. A systematic analysis using the fifteen Zebra danio SULTs revealed that SULT3 ST2 and SULT3 ST3 were the major bile acid/alcohol-sulfating SULTs. Among the eleven human SULTs, only SULT2A1 was found to be capable of sulfating bile acids and bile alcohols. To further investigate the sulfation of bile acids and bile alcohols by the two Zebra danio SULT3 STs and the human SULT2A1, pH-dependence and kinetics of the sulfation of bile acids/alcohols were analyzed. pH-dependence experiments showed that the mechanisms underlying substrate recognition for the sulfation of lithocholic acid (a bile acid) and 5α-petromyzonol (a bile alcohol) differed between the human SULT2A1 and the Zebra danio SULT3 ST2 and ST3. Kinetic analysis indicated that both the two Zebra danio SULT3 STs preferred petromyzonol as substrate compared to bile acids. In contrast, the human SULT2A1 was more catalytically efficient toward lithocholic acid than petromyzonol. Collectively, the results imply that the Zebra danio and human SULTs have evolved to serve for the sulfation of, respectively, bile alcohols and bile acids, matching the cholanoid profile in these two vertebrate species.     

Sub-lethal effect of synthetic pyrethroid pesticide on metabolic enzymes and protein profile of non-target Zebra fish,Danio rerio

Extensive application of pesticide in agricultural field affects the enzymatic activity of non-target animals, including fishes. In this study, the impact of sublethal concentration of fenvalerate on marker enzymes of freshwater Zebra fish was evaluated. Pesticide-induced stress can specifically affect non target fishes, through elevated level of reactive oxygen species which is responsible for biochemical, cell metabolism and physiological activities. The oxidative stress mediated by fenvalerate at sub lethal concentrations after 28 days of exposure of Zebra fish. Following 28 days of exposure of pesticide, catalase, superoxide dismutase, aspartate amino transferases, alanine amino transferase, alkaline phosphatase and acid phosphatase were assessed. Results revealed reduction of superoxide dismutase activity after 28 days of exposure in sub lethal concentration of fenvalerate in liver and gills. In liver, catalase activity was found to be less in fenvalerate exposed fish than control fish. In liver, increase of 75.75% aspartate amino transferase and 38% increase in alanine amino transferase in gills. SGPT activity was relatively higher than SGOT suggests more contribution of phyruvalate than oxaloacetate formation. Fenvalerate induced changes in acid phosphatase and alkaline phosphatase activity in the liver and gills of Zebra fish after four weeks of exposure. Fenvalerate induced expression of various stress proteins in gill, liver, followed by muscle. Some proteins lost its intensity due to fenvalerate toxicity. Result revealed that enzyme assays and SDS-PAGE analysis for protein subunits determination is relevant tool to monitor stress in freshwater ecosystem. The findings suggest that in monitoring fenvalerate toxicity programme, enzyme activities can be potent diagnostic tool for fenvalerate induced toxicity.     

High velocity mechanical injection of foreign DNA into fish oocytes

High-velocity tungsten microprojectiles were used to introduce into fertilized eggs of loach (Misgurnus fossilis), Rainbow trout (Salmo gairdneri Rich.) and Zebra fish (Brachydanio rerio) DNA sequences of beta-galactosidase and neomycin phosphotransferase genes. No more than 30% of fish oocytes died as a result of bombardment. Experiments revealed marked activity of both enzymes in developing fishes. Neo gene DNA sequences were found in total danio DNA using PCR technique.     

Using a zebrafish Danio rerio model system to study NOTCH1‐induced T‐cell leukaemia

Notch receptors are a family of cell‐surface proteins that regulate cell fate decisions and growth control. Human NOTCH1 gain‐of‐function mutations–deletions have been found in c. 60% of patients with T‐cell acute lymphoblastic leukaemia (T‐ALL). Therefore, understanding the molecular mechanisms by which dysregulated Notch‐signalling induces leukaemia is of importance and may reveal novel targets for the development of more effective therapies. Zebrafish, Danio rerio, is an ideal model system to use for forward genetic screens to uncover pathways critical for transformation. Danio rerio also have the capacity for small molecule screening for drug discovery. rag2‐ICN1‐EGFP transgenic fish have been created that develop a T‐cell leukaemia, and these fish are now being used in genetic modifier screens.     

云南属鱼类一新种(鲤形目:鲤科)

本文报道采自云南省的属鱼类一新种—勐腊Ｄａｎｉｏｍｅｎｇｌａｅｎｓｉｓｓｐ．ｎｏｖ。新种与ＤａｎｉｏｃｈｒｙｓｏｔａｅｎｉａｔｕｓＣｈｕ和ＤａｎｉｏｐｏｎｔｉｃｕｌｕｓＳｍｉｔｈ近似。模式标本保存于中国科学院水生生物研究所淡水鱼类博物馆。     

Genomics and mapping of teleostei (bony fish)

Until recently, the Human Genome Project held centre stage in the press releases concerning sequencing programmes. However, in October 2001, it was announced that the Japanese puffer fish (Takifugu rubripes, Fugu) was the second vertebrate organism to be sequenced to draft quality. Briefly, the spotlight was on fish genomes. There are currently two other fish species undergoing intensive sequencing, the green spotted puffer fish (Tetraodon nigroviridis) and the zebrafish (Danio rerio). But this trio are, in many ways, atypical representations of the current state of fish genomic research. The aim of this brief review is to demonstrate the complexity of fish as a group of vertebrates and to publicize the 'lesser-known' species, all of which have something to offer.     

Conservation of the gene structure and membrane-targeting signals of germ cell-specific lamin LIII in amphibians and fish

Targeting of nuclear lamins to the inner nuclear membrane requires CaaX motif-dependent posttranslational isoprenylation and carboxyl methylation. We previously have shown that two variants of lamin LIII (i.e., LIII and LIIIb) in amphibian oocytes are generated by alternative splicing and differ greatly in their membrane association. An extra cysteine residue (as a potential palmitoylation site) and a basic cluster in conjunction with the CaaX motif function as secondary targeting signals responsible for stable membrane association of lamin LIIIb. cDNA sequencing and genomic analysis of the zebrafish Danio rerio lamin LIII uncovers a remarkable conservation of the genomic organization and of the two secondary membrane-targeting signals in amphibians and fish. The expression pattern of lamin LIII genes is also conserved between amphibians and fish. Danio lamin LIII is expressed in diplotene oocytes. It is absent from male germ cells but is expressed in Sertoli cells of the testis. In addition, we provide sequence information of the entire coding sequence of zebrafish lamin A, which allows comparison of all major lamins from representatives of the four classes of vertebrates.     

Olfactorily-mediated cortisol response to chemical alarm cues in zebrafish Danio rerio

Chemical cues released as a by-product of predation mediate antipredator behaviour, but little is known about the physiological responses to olfactory detection of predation risk. In this study, zebrafish Danio rerio were exposed to either chemical alarm cues from conspecifics, or water (control). Compared with water controls, D. rerio exposed to alarm cues responded behaviourally with antipredator behaviours such as erratic dashing and an increase in time spent near the bottom of the test aquarium. Danio rerio were sacrificed 5 min after exposure to test cues (alarm cues or water). Enzyme-linked immunosorbent assay (ELISA) revealed whole-body levels of cortisol that were significantly higher for fish exposed to alarm cues (mean ± SE, 11.9 ± 3.4 ng g⁻¹) than control fish (1.5 ± 0.7 ng g⁻¹). These data provide a benchmark for future studies of the proximate mechanisms of olfactorily mediated antipredator responses, modelling effects on aquatic life in a changing climate and, as a model organism, Danio rerio can further our understanding of anxiety in humans.     

Development and application of methods for investigating the ratio of rheoreaction types of fish in a circular tank

Methods for evaluating the motivational component of the fish rheoreaction (ratio of rheoreaction types) are developed and tested in a circular hydrodynamic tank for three fish species (Danio rerio, Poecilia reticulata, and Inpaichthys kerri). Three rheoreaction types of fish were distinguished: a positive type (fish movements against water current), a negative type (fish movements along with water current), and a compensatory type (fish maintaining their position in relation to immobile reference points). The main distinguishing features of these new methods are unrestricted distance for fish movements, continuous monitoring of individual fish movements (video recording), and evaluation of ratio between the types of rheoreaction in terms of duration of demonstration of these types by each. The minimum required observation time and water current velocities are determined. It is shown that these methods can be used for investigating the types of rheoreaction in different fish species. Every single individual repeatedly demonstrated all these three rheoreaction types during the test.     

The distribution and habitat preferences of the zebrafish in Bangladesh

The present study presents the results of a survey of a wide range of water bodies in Bangladesh to identify and describe Danio rerio habitat preferences. Field-based experiments were conducted to determine the vertical distribution of D. rerio in the water column, together with five other fish species commonly found in association with D. rerio. Danio rerio is a floodplain rather than riverine species, being most abundant in shallow lakes, ponds and ditches, typically in open locations with relatively clear water and abundant vegetation at the margins. It is commonly found in water bodies with a connection to rice cultivation and is more common in the north of Bangladesh than the south. Danio rerio occupies the whole of the water column and is observed as frequently in open water as amongst aquatic vegetation.     

Fish models in prion biology: Underwater issues

Transmissible spongiform encephalopathies (TSEs), otherwise known as prion disorders, are fatal diseases causing neurodegeneration in a wide range of mammalian hosts, including humans. The causative agents - prions - are thought to be composed of a rogue isoform of the endogenous prion protein (PrP). Beyond these and other basic concepts, fundamental questions in prion biology remain unanswered, such as the physiological function of PrP, the molecular mechanisms underlying prion pathogenesis, and the origin of prions. To date, the occurrence of TSEs in lower vertebrates like fish and birds has received only limited attention, despite the fact that these animals possess bona fide PrPs. Recent findings, however, have brought fish before the footlights of prion research. Fish models are beginning to provide useful insights into the roles of PrP in health and disease, as well as the potential risk of prion transmission between fish and mammals. Although still in its infancy, the use of fish models in TSE research could significantly improve our basic understanding of prion diseases, and also help anticipate risks to public health. This article is part of a Special Issue entitled Zebrafish Models of Neurological Diseases.     

Complement activity in the egg cytosol of zebrafish Danio rerio: evidence for the defense role of maternal complement components

Most fish embryos that develop externally are exposed to an environment full of microbes. How they survive microbial attacks are not understood to date. Here we demonstrated that the egg cytosol prepared from the newly fertilized eggs of zebrafish Danio rerio is capable of killing the Gram-negative bacterium Escherichia coli, via in vitro assay system of the complement activity established. All findings indicate that it is the complement system operating via the alternative pathway that is attributable to the bacteriolytic activity. This is the first report providing the evidence for the functional role of the maternal complement components in fish eggs, paving the way for study of maternal immunity in other organisms whose eggs are fertilized in vitro.     

斑马鱼和鲤miR-1-2/133a-1基因间序列活性和调控研究

分别以斑马鱼(Danio rerio)和鲤(Cyprinus carpio L.)为研究材料,通过克隆斑马鱼和鲤miR-1-2和133a-1的基因间增强子序列,利用活体和离体实验探讨其是否具有肌肉特异性;并通过荧光素酶报告系统等研究转录因子MyoD是否调控该序列.研究结果显示:在活体实验中,无论斑马鱼还是鲤,miR-1...     

Expression change in Angiopoietin-1 underlies change in relative brain size in fish

Brain size varies substantially across the animal kingdom and is often associated with cognitive ability; however, the genetic architecture underpinning natural variation in these key traits is virtually unknown. In order to identify the genetic architecture and loci underlying variation in brain size, we analysed both coding sequence and expression for all the loci expressed in the telencephalon in replicate populations of guppies (Poecilia reticulata) artificially selected for large and small relative brain size. A single gene, Angiopoietin-1 (Ang-1), a regulator of angiogenesis and suspected driver of neural development, was differentially expressed between large- and small-brain populations. Zebra fish (Danio rerio) morphants showed that mild knock down of Ang-1 produces a small-brained phenotype that could be rescued with Ang-1 mRNA. Translation inhibition of Ang-1 resulted in smaller brains in larvae and increased expression of Notch-1, which regulates differentiation of neural stem cells. In situ analysis of newborn large- and small-brained guppies revealed matching expression patterns of Ang-1 and Notch-1 to those observed in zebrafish larvae. Taken together, our results suggest that the genetic architecture affecting brain size in our population may be surprisingly simple, and Ang-1 may be a potentially important locus in the evolution of vertebrate brain size and cognitive ability.     

The influence of alarm substance and shoal size on the behaviour of zebra danios, Brachydanio rerio (Cyprinidae)

Timidity, vigilance and response to alarm substance were examined in shoals consisting of one to 12 zebra danios, Brachydanio rerio . Measures of timidity were not clearly related to shoal size. Fish in larger shoals spent more time in central areas of the tank away from cover than fish in smaller shoals. However, fish in small shoals appeared to be as aggressive as those in larger shoals. Vigilance and foraging rates did not appear to be related to shoal size. Per capita foraging rates and shoal size were not correlated. After being frightened by alarm substance, danios in larger shoals did not return to foraging sooner than those in smaller groups. Zebra danios in all shoal sizes responded behaviourally to alarm substance. It appears that the presence of conspecifics is unnecessary for alarm behaviours to occur and that the nature of the behaviours are independent of shoal size.