斑马 水粉画

那规则排列方向变化的线条给我非常强的冲击力！斑马的一家在茂盛的草地上悠闲地散步，多么富有诗意啊！

斑马城市

我生活的城市里，住着一位斑马先生，他常常向我抱怨说：“为什么，这个城市里有那么多的人，那么多的汽车，那么多的房子。那么多的老鼠。而只有我一只斑马。”

流浪的歌声,繁华的城市——歌词《斑马,斑马》赏析

本文从多角度赏析了民谣《斑马,斑马》,把作者的自我感觉、评介融入对歌词的理解和传唱中,将梦想与现实、心灵和本真交相述说,剖析了歌手求而不得的惆怅和痛苦,将深入骨髓的悲伤用文字诗意传达。

斑马的问题

我问斑马，你是有白条纹的黑马，还是有黑条纹的白马？斑马反过来问我，

Real-time Quantitative PCR Analysis of Vascular Endothelial Growth Factor Receptor-2(VEGFR-2) Expression at Zebrafish Different Developmental Stages

[Objective]To investigate the expression of zebrafish vascular endothelial growth factor-2（VEGFR-2） at different developmental stages.[Method]Total RNAs were extracted from 12,24,48,72 and 96 hpf stage zebrafish embryos and larvae.Real-time quantitative RT-PCR was performed to examine the expression of VEGFR-2.The data were analyzed by 2^-△△Ct method.[Result]The expression level of VEGFR-2 gene increased gradually from 12 to 72 hpf,and subsequently decreased at 96 hpf.The expression level was lowest at 12 hpf,highest at 72 hpf,and had significant differences when compared with that of other developmental stages.[Conclusion]The expression level of VEGFR-2 increases gradually before blood vessel maturation and decreases as blood vessels mature.

Baiting Effects of 17 Chinese Medicinal Plants on Brachydanio rerio

The study aimed to discuss baiting effects of 17 kinds of Chinese medicinal plants on Brachydanio rerio.With 100 fish of Brachydanio rerio as tested objects,the average length of the 100 fish was 3.5 cm.Cinnamomum cassia,Mentha canadensis,Eugenia aromaticum,Coptis chinensis,Phellodendron amurense,Scutellaria baicalensis,star anise,Kaempferia galanga,Prunus mume,Magnolia sinensis,Terminalia chebula meat,Sophora flavescens,Polygonum cuspidatum,Rhizoma polygonatum,Astragalus membranaceus,Forsythia suspense and...

Study on the Acute Toxicity and Genetics Toxicity of Bensulfuronk-methyl on Danio rerio

[Objective] The aim was to study the effect of bensulfuron-methyl herbicide on acute toxicity and genetics toxicity of Danio redo. [ Method] Median lethal concentration was calculated by acute toxicity test, and analyzing the herbicide whether existing in potential toxicity to aquatic organisms or not. Based on the study of acute toxicity, genetics toxicity was carried out, by calculating the micronucleus rate to judge bensulfuron-methyl herbicide whether existing in potential toxicity or not. [ Result ] The LD5o （24 h and 48 h） of bensulfuron-methyl herbicide are 0.698 ml/L and 0.637 ml/L respectively, the safe concentration was 0.159 ml/L. The results on the effects of micronucleus （MN） in erythrocytes of Danio redo induced by bensulfuron-methyl at different times and different concentrations showed that the MN rate of control group was 0.010 3%, the highest MN rate of experimental group reached to 0. 372%, it also indicated that bensulfuron-methyl herbicide had genetics toxicity to Danio redo. At the same detection time, there was dose-effect relationship of MN rate in erythrocytes between treatment and control groups with different concentrations. In the same treatment group, the MN rate in erythrocytes reached to peak value at 24 h, and decreased at 48 h and 72 h with the infection time was prolonged. [ Conclusion ] The study provides some basis for scientifically selecting and reasonably using herbicide.

Histological Study on the Adrenal Gland of Zebra

In order to explore the histological structure of zebra and to protect en- dangered species diversity, it is especially important to study the zebra adrenal his- tological structure. 2 zebra adrenals were studied by means of histological methods. The adrenal gland tissues were dissected into serial paraffin sections at the thick- ness of 3 μm. After HE and Masson staining, they were observed and photographed by the light microscope and Image-Pro Plus 6.0. The results show that zebra adrenal capsule is covered with thick connective tissue, which is about 230 μm. A large number of nerves and blood vessels are distributed in the capsule. The area of cortex is about 5 times larger than medullae. Zona glomerulosa is thin, about 300？m. The cells were arranged as column and ball. Zona fasciculata with the thickness of 1 750 μm is 6 times as thick as zona glomerulosa. The cells were ar- ranged in cord. Zona reticular with the thickness of 250 wm was closely adjacent to medulla and formed a jagged boundary. The medulla with the area of 4 mm2 was deeply dyed. It was concluded that some sympathetic ganglion cells were found in the medulla arranged in groups and surrounded with zona reticular cells but lots of the cells were found in zona reticular. Some connective tissue with chromaffin cells was found in the medulla center vein. The purpose of the present study provides reliable evidences for further study on morphology, physiology and pathology of the zebra.

Identification of Z-OTU protein during zebrafish oogenesis and early embryogenesis

Zebrafish（Danio rerio） Z-OTU,containing OTU and TUDOR domains,was predicted to be a member of OTU-related protease,a family of the deubiquitylating enzymes（DUBs）.A previous report from our laboratory clearly describes the expression patterns of z-otu mRNA.Here,we characterized the Z-OTU protein during zebrafish oogenesis and early embryogenesis.After prokaryotic expression,the recombinant protein of the OTU domain and GST was purified and injected into rabbits to obtain the polyclonal antibody-anti-Z-OTU,which was used for immunohistochemistry in zebrafish ovaries and embryos.Interestingly,obvious differences existed between the expression patterns of z-otu mRNA and its protein during oogenesis and early embryogenesis.In stage I oocytes,z-otu mRNA was detected in cytoplasm while its protein existed in the germinal vesicle.In addition,its protein was distributed during entire oogenesis,while mRNA was not detected in oocytes at stage IV or mature oocytes.The z-otu mRNA disappeared after midblastula transition（MBT） and its protein gradually decreased after this stage.We inferred that Z-OTU protein,like other OTU-related protease with DUB activity,was required for germinal vesicle breakdown of oocytes during meiosis,germinal vesicle migration,and embryo cleavage maintenance.

Identification of zRAP55,a gene preponderantly expressed in StagesⅠandⅡ oocytes of zebrafish

In an in silico search for gonand specific expressed genes, we have identified zRAP55 which is enriched in the ovary of zebrafish . zRAP55 encodes a protein of 382 amino acids with a highly conserved Lsm domain. zRAP55 protein shares more than 56% identities with that of other vertebrate species. RT-PCR results show that it is predominantly expressed in the ovary. In situ hybridization and immunohistochemistry studies reveal that zRAP55 is ubiquitously dispersed throughout the cytoplasm of stages Ⅰ and Ⅱ oocytes, whereas no expression is observed in stages Ⅲ and Ⅳ oocytes. As an RNA associated protein, zRAP55 might function in the control of protein translation at the early stages of oogenesis in zebrafish.

Developmental expression of Cyclin H and Cdk7 in zebrafish: the essential role of Cyclin H during early embryo development

Cyclin-dependent kinase 7 （Cdk7） is the catalytic subunit of the metazoan Cdk-activating kinase （CAK）. Activation of Cdk7 requires its association with a regulatory subunit, Cyclin H. Although the Cdk7/Cyclin H complex has been implicated in the regulation ofRNA polymerase in several species, the precise function of their orthologs in zebrafish has not been fully elucidated. In this study, we isolated from zebrafish blastula embryos two cDNAs encoding the orthologs of human Cyclin H and Cdk7, and examined the role of Cdk7/Cyclin H in zebrafish embryogenesis. Sequence analysis showed that the zebrafish Cyclin H and Cdk7 cDNAs encode proteins with 65% and 86% identity to the respective hu- man orthologs. RT-PCR and whole-mount in situ hybridization analyses of their expression in unfertilized eggs, embryos and organs of adult fish suggested that Cyclin H and Cdk7 messages are maternally loaded. Our data also showed that their transcripts were detected throughout development. Distribution of Cyclin H transcripts was found to be ubiquitous during early stages of development and become restricted to the anterior neural tube, brain, eyes, procreate tissues, liver and heart by 5 days post-fertilization. Expression of a dominant-negative form of Cyclin H delayed the onset of zygotic transcription in the early embryo, resulting in apoptosis at 5 hours post-fertilization and leading to sever defects in tis- sues normally exhibiting high levels of Cyclin H expression. These results implicate Cyclin H in the regulation of the transcriptional machinery during midblastula transition and suggest that it is an essential gene in early zebrafish larval development.

Small ubiquitin-related modifier paralogs are indispensable but functionally redundant during early development of zebrafish

The Small ubiquitin-related modifier （SUMO） conjugation to a variety of proteins regulates diverse cellular processes, including transcription, cell cycle regulation and maintenance of genome integrity. To investigate in vivo biological function of SUMO paralogs, we inactivated them in the early development of zebrafish. While zebrafish embryos deficient for all three SUMO paralogs, as Ubc9-deficient ones, displayed severe defects, loss of individual SUMO paralog was compatible with a normal development. SUMO-deficient embryos can be rescued by a single human or zebrafish SUMO. While key structural basic lysine residues and N-terminal unstructured stretch of SUMO are critical for in vivo rescue, the consensus Kll sumoylation site of SUMO2 is dispensable, implying that chain formation on this potential site is unessential for normal development. Inactivation of all three SUMOs triggered p53- dependent apoptosis and further inactivation of p53 restored normal zebrafish development. Interestingly, we also demonstrate that the dominant negative truncated form of p53, Δ113p53, significantly blunts SUMO depletion-induced p53 activity in vivo. Taken together, our results suggest that SUMO paralogs are indispensable, but redundant, in the early development of zebrafish.

Acute toxicity effects of perfluorooctane sulfonate on sperm vitality,kinematics and fertilization success in zebrafish

Perfluorooctane sulfonate （PFOS） has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertilization success in zebrafish （Danio rerio）. Sperm were activated in aqueous media containing a range of PFOS concentrations （0, 0.09, 0.9 and 9 mg/L）. Viabilities and kinematics of the sperm exposed to different PFOS treatments were assessed via computer-assisted sperm analysis （CASA） at 20, 40, 60, and 80 s after activation. PFOS exposure decreased the percentage of motile sperm, the curvilinear velocity （VCL）, and the mean angular displacement （MAD） of spermatozoa, but showed no influence on the straight- line velocity （VSL） or the angular path velocity （VAP）. Furthermore, a significant decrease in fertilization success was observed in spermatozoa that were exposed to 0.9 mg/L PFOS or more. These findings indicate that PFOS pollution in natural aquatic environment may be a potential threaten to successful reproduction of fish.

Genes of the adaptive immune system are expressed early in zebrafish larval development following lipopolysaccharide stimulation

Information regarding immunocompetence of the adaptive immune system （AIS） in zebrafish Danio rerio remains limited. Here, we stimulated an immune response in fish embryos, larvae and adults using lipopolysaccharide （LPS） and measured the upregulation of a number of AIS-related genes （Rag2, AID, TCRAC, IgLC-1, mIg, slg, IgZ and DAB） 3 and 18 h later. We found that all of the genes evaluated were strongly induced following LPS stimulation, with most of them responding at 8 d post fertilization. This confirms that a functional adaptive immune response is present in D. rerio larvae, and provides a window for further functional analyses.

Evaluation of Cytotoxicity and Genotoxicity of Insecticide Carbaryl to Flounder Gill Cells and Its Teratogenicity to Zebrafish Embryos

In this study, we determined the cytotoxicity and genotoxicity of carbamate insecticide carbaryl to flounder gill （FG） cells and its teratogenicity to zebrafish embryos. The cytotoxicity of carbaryl to FG cells was determined with methods including MTT and neutral red uptaking （NRU）, lactate dehydrogenase （LDH） releasing and Hoechst 33342 and propidiurn idodide （PI） double staining. Moderate cytotoxicity in a concentration-dependent manner was observed. The 24h-IC50 value of 53.48 ± 1.21, 59.13 ± 1.19 and 46.21 ± 1.24 mgL 1 carbaryl was obtained through MTT, NRU and LDH assays, respectively. Double fluorescence staining dem- onstrated that carbaryl induced the death of FG cells mainly through necrosis. There was no significant genotoxicity found in the FG cells exposed to the highest testing concentration of carbaryl （20mgL-1, P〉0.05） as was demonstrated by Comet assay. Zebrafish embryos exposed to carbaryl at concentrations 〉10 mg L-1 displayed moderate toxic effects on the survival, spontaneous movement, hatching, heart rates of the embryos and their development, which were evidenced by yolk and pericardial sac edemas, body length reduction and tail flexure in time- and concentration-dependent manners at specific stages. The 24h-, 48h- and 96h-LC50 values of carbaryl to zebra fish embryos were 41.80 ± 1.10, 17.80 ± 1.04 and 14.46 ± 1.05 mg L-1, respectively. These results suggested that car- baryl is moderately toxic to FG ceils cultured in vitro and zebrafish embryos, and the FG cells were similar to zebrafish embryos in their sensitivity to carbaryl as 24h-IC50 and LC50 indicated.

Development of a Zebrafish Model for Rapid Drug Screening against Alzheimer＇s Disease

Alzheimer＇s disease, the leading cause of dementia in the elderly, is a complex neurodegenerative disorder which leads to a progressive decline in cognitive functions. A rapid screening model is highly demanded for identification and evaluation of novel anti-Alzheimer＇s disease drugs from a large numbers of compounds. Until now, numerous studies utilized zebrafish model for drug discovery. Since aluminum can induce a similar biological activity in zebrafish as in Alzheimer patients, in this study, we developed a novel animal model using 3 to 5 day post-fertilization larval zebrafish by optimizing the doses and duration of aluminum chloride exposure. Six anti-Alzheimer＇s disease drugs with a variety of mechanisms were tested to validate the newly developed zebrafish model. Importantly, Rivastigmine, ThT, Flurbiprofen and AM-117 could increase the value of Dyskinesia Recovery Rate by 53.4-64%, 169.4-200%, 54.5-96% and 70.9-121%, respectively. Rivastigmine, Memantine, ThT, Flurbiprofen, Rosiglitazone and AM-117 improved the value of Response Efficiency by 86.6-175.1%, 28.2-66.6%, 127.2-236.5%, 118.3-323.7%, 26.6-140.8% and 70.2-161.4%, respectively. Our results suggest that the zebrafish model developed in this study could be a useful tool for high throughput screening of potential novel anti-Alzheimer＇s disease leading compounds targeting acetylcholinesterase, N-methyl-D-aspartic acid receptor, γ-secretase, peroxisome proliferator-activated receptor-γand amyloid-β.

Characterization of DYRK2(dual-specificity tyrosine-phosphorylation-regulated kinase 2) from Zebrafish(Dario rerio)

Proteins of the DYRK(dual-specificity tyrosine-phosphorylation-regulated kinase) family are characterized by the presence of a conserved kinase domain and N-terminal DH box.DYRK2 is involved in regulating key developmental and cellular processes,such as neurogenesis,cell proliferation,cytokinesis,and cellular differentiation.Herein,we report that the ortholog of DYRK2 found in zebrafish shares about 70% identity with that of human,mouse,and chick.RT-PCR showed that DYRK2 is expressed maternally and zygotically.In-situ hybridization results show that DYRK2 is expressed in somite cells that will develop into muscles.Our results provide preliminary evidence for investigating the in-vivo function of DYRK2 in zebrafish muscle development.

In vivo effects of 17-β-estradiol on plasma immunoglobulin levels and leukocyte density in zebrafish Danio rerio

Estradiol, or 17-β-estradiol （E2）, the most potent naturally occurring estrogen, is involved in the hormone-immune system interaction in both mammals and fish. However, in vivo studies are largely limited, and little is known about whether E2 exerts similar effects on both female and male zebrafish （Danio rerio）. Here, we show exposure of both sexes ofD. rerio to 20 nmol/L E2 resulted in a significant increase in Vgl expression, but caused little damage to the hepatocytes, suggesting that this is the optimum E2 concentration. Also, exposure to 20 nmol/L E2 for 20 days caused a marked increase in plasma IgM levels, but had little influence on the peripheral leukocyte density, providing the first evidence of a hormone-immune system interaction in this species.

Effects of Boscalid on the Antioxidant Enzyme System of Adult Zebrafish (Danio rerio)

Abstract [Objective] This study was conducted to evaluate the ecotoxicity of boscalid to adult zebrafish （Danio rerio）. [Method] The activities of antioxidant enzymes superoxide dismutase （SOD）, catalase （CAT）, peroxidase （POD）, glutathione peroxidase （GPx）, as well as a non-enzymatic antioxidant malondialdehyde （MDA）, in the liver were measured 3, 7, 14 and 21 d post exposure （dpe） to 0.02 （1/100 of acute toxicity）, 0.036 （monitored concentration）, 0.08 （1/20 of acute toxicity）, 0.16 （1/10 of acute toxicity） and 0.32 mg/L （1/5 of acute toxicity） boscalid using a semi-static method. [Result] SOD, CAT, POD, GPx and MDA activity in the liver of zebrafish varied with boscalid concentration and exposure time. Boscalid significantly enhanced MDA content at 21 dpe. A significant upregulation of the activity of SOD, CAT, POD and GPx at 7 dpe was observed, suggesting that boscalid resulted in oxidative stress and lipid peroxidation. [Conclusion] These results show that these biomarkers are all appropriate for monitoring oxidative stress and the lipid peroxidation status of fish after exposure to boscalid. Key words Boscalid; Zebrafish; Antioxidant enzyme