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991.
The Neotropical freshwater fish fauna is very rich—according to the most recent catalogue 71 families and 4,475 species have
been described. However, only a small amount of general information is available on the composition of Neotropical marine
fishes. In Brazil, 1,298 marine species have been recorded. General analysis of available cytogenetic and population genetic
data clearly indicates research has been mainly concentrated on freshwater fishes. Thus, today, cytogenetic information is
available for 475 species of Characiformes, 318 species of Siluriformes, 48 species of Gymnotiformes, 199 freshwater species
that do not belong to the superorder Ostariophysi, and only 109 species of marine fishes. For the species studied, only about
6% have sex chromosomes and about 5% have supernumerary or B chromosomes. A review of the cytogenetic studies shows that these
data have provided valuable information about the relationships between fish groups, the occurrence of cryptic species and
species complexes, the mechanism of sex determination and sex chromosome evolution, the distribution of nucleolus organizer
regions, the existence supernumerary chromosomes, and the relationship between polyploidy and evolution. In relation to populations
in Neotropical marine waters, the studies have shown the presence of cryptic species, which has important implications for
fishery management. Different levels of genetic structuring can be found among Neotropical freshwater migratory fish species.
This raises important implications for fish population genetic diversity and consequently its sustainable utilization in inland
fisheries and aquaculture, specifically for conservation of ichthyo-diversity and survival. 相似文献
992.
993.
Characterization and application of monoclonal antibodies against white spot syndrome virus 总被引:1,自引:1,他引:1
Three hybridoma clones secreting monoclonal antibodies (MAbs) were produced from mouse myeloma and spleen cells immunized with white spot syndrome virus (WSSV) isolated and purified from Penaeus monodon (Fabricius), collected from north-eastern Taiwan. By sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE), the protein profile of this isolate contained four major proteins with sizes of approximately 35 (VP35), 28 (VP28), 24 (VP24), and 19 kDa (VP19). Western blot analysis revealed that two MAbs (1D7 and 6E1) recognized epitopes on VP28 and one MAb (3E8) recognized an epitope on VP19. The MAb 6E1 isotyped to the IgG1 class was used in both an indirect immunofluorescence assay (IFA) and in an immunochemical staining protocol for successful identification and localization of WSSV in infected shrimp tissues. Antigenic similarity of isolates from Indonesia and Malaysia to the Taiwan isolate was illustrated by IFA with MAb 6E1. A MAb (2F6) which bound specifically to two shrimp proteins, 75 and 72 kDa, and reacted to the healthy and non-target tissues of WSSV in infected shrimp, such as hepatopancreas, is also described here and shows the necessity for specific identification of antibodies. 相似文献
994.
Development of a rapid assay for the diagnosis of Myxobolus cerebralis in fish and oligochaetes using loop-mediated isothermal amplification 总被引:1,自引:0,他引:1
A loop-mediated isothermal amplification assay was developed for the rapid detection of Myxobolus cerebralis in both fish and oligochaete hosts. The assay was optimized to amplify parasitic DNA by incubation with Bst DNA polymerase and a set of six specially constructed primers at 65 degrees C for 60 min. The amplification products were detected visually using SYBR Green I dye which gave identical results to gel electrophoresis analysis. Parasite DNA was detected from infected oligochaetes, and from the anal fin, caudal fin, dorsal fin and operculum of clinically infected fish. This 'Myxo-LAMP' assay has a detection limit similar to that of a polymerase chain reaction assay (10(-6)), but is more rapid and only requires a water bath for amplification and is therefore practical for simple and rapid diagnosis of infected tissue. 相似文献
995.
A qPCR assay was developed for rapid and sensitive detection of Flavobacterium psychrophilum, the aetiological agent of bacterial cold-water disease and rainbow trout fry syndrome in salmonid fish worldwide. A set of F. psychrophilum-specific primers based on 16S rRNA gene sequences was designed and validated for specific detection and quantification of DNA isolated from representative strains of F. psychrophilum. The qPCR assay exhibited a high specificity for the 16S rRNA gene of F. psychrophilum (from 4 × 10(8) down to 11 copies per reaction) but not for other Flavobacterium species or other bacteria including fish pathogens. This qPCR-based method proved to be useful in the quantification of the F. psychrophilum titre present within organs dissected out from diseased fish. As the F. psychrophilum genome contains six copies of the 16S rRNA gene, we could infer a limit of detection corresponding to two bacteria per reaction, corresponding to 800 bacteria per fish tissue sample, and therefore 20 F. psychrophilum cells mg(-1) of tissue (for sample weighing 40 mg). The qPCR assay reported here could be a useful tool for veterinary diagnostic laboratories to monitor the F. psychrophilum infection level in fish farms. 相似文献
996.
997.
998.
IBD的RT-PCR快速诊断技术的建立 总被引:2,自引:0,他引:2
根据已发表的IBDV各致病型毒株的序列,在VP5和VP2的重叠基因区设计合成了一对寡核苷酸引物,对2株参考毒株和8份疑似IBD的临床病料进行RT-PCR检测均得到了明显的阳性扩增结果;而对作为阴性对照的常见4种鸡病病原:鸡新城疫病毒、鸡传染性支气管炎病毒、鸡马立克氏病病毒、大肠杆菌均没有扩增到任何片段。利用琼脂扩散试验进行IBDV病原常规鉴定,结果证实5份病料呈现IBD阳性。表明建立的IBD的RT-PCR诊断技术具有快速、特异、敏感的特点。 相似文献
999.
鸡毒支原体研究进展 总被引:11,自引:0,他引:11
鸡毒支原体 (MG)会引发鸡的慢性呼吸道疾病和火鸡传染性窦炎 ,是最主要的禽病原菌之一 ,它给养鸡业带来很大的经济损失。目前常用的诊断方法有病原菌的分离鉴定和血清学方法。血清学方法有平板凝集试验、血凝抑制试验、EL ISA、PPA-EL ISA等。分子生物学方法也逐渐应用于鸡毒支原体的诊断 ,如细胞蛋白SDS-PAGE分析、限制性内切酶分析、PCR等。鸡毒支原体的防治主要有疫苗预防和药物治疗。从目前来看疫苗预防仅能提供有限的保护 ,药物治疗不能完全消灭 MG。MG发病机制的研究、先进的诊断方法的探索、高效疫苗的研制、推广及应用是禽病工作者亟待解决的问题 相似文献
1000.
研究了用生物素标记的寡核苷酸DNA探针快速检测鱼传染性胰脏坏死病病毒IPNV,取得了较好的结果。对探针的灵敏度,特异性进行了灵敏度、特异性进行了测定,并与其它快速检测技术作了比较。 相似文献