背景:患病率,形态学,以及欧洲海底等足病的分子特征,双entrarchuslabrax,在埃及,使用光镜和电子显微镜以及靶向线粒体COI(细胞色素氧化酶c)基因的聚合酶链反应进行了评估。
结果:成年寄生虫主要在g弓之间的分支腔中发现,而在颊腔中的程度较小。它们在形态学上被鉴定为CymothoidaeLivonecaredmaniiLeach,1818年(甲壳类动物:Isoboda)。显然,据报道,在埃及地中海水域的D.labrax中,等足类动物的患病率为23%。观察到破坏性和退行性坏死改变,并使受感染的鱼的g片完全脱落。线粒体COI基因的DNA测序证实了寄生虫的鉴定,该寄生虫以登录号MW600099,MZ208984和MZ208985保存在GenBank中。此外,系统发育分析表明,寄生虫是从与雷德曼氏杆菌紧密相关的单系进化枝出现的,并且与其他等足物种有明显区别。
结论:本研究针对埃及D.labrax中的雷德曼氏杆菌感染,并通过扫描电子显微镜(SEM)和该等足类物种的分子特征确认了形态特性。在临床和组织病理学上都证明了这种寄生虫对感染鱼的巨大影响。
BACKGROUND: Prevalence, morphology, and molecular characteristics of isopodiosis in the European seabass, Dicentrarchus labrax, in Egypt were assessed using light and electron microscopy and polymerase chain reaction targeting the mitochondrial COI (cytochrome oxidase c) gene.
RESULTS: Adult parasites were found mainly in the branchial cavity between gill arches and to a lesser extent in the buccal cavity. They were morphologically identified as the Cymothoidae Livoneca redmanii Leach, 1818 (Crustacea: Isopoda). Obviously, a 23% prevalence rate of isopods was reported in D. labrax from Egyptian Mediterranean waters. Destructive and degenerative necrotic alterations with complete sloughing of gill lamellae of the infested fish were observed. DNA sequencing of the mitochondrial COI gene confirmed the identification of the parasite which was deposited in the GenBank under accession numbers MW600099, MZ208984, and MZ208985. Furthermore, the phylogenetic analysis demonstrated that parasites emerged from a monophyletic clade closely affiliated with L. redmanii and were clearly distinguished from other isopod genospecies.
CONCLUSIONS: The present investigation addresses L. redmanii infestation in D. labrax in Egypt and affirmed morphological properties via the scanning electron microscopy (SEM) and molecular characteristics of this isopod species. The drastic effects of this parasite on the infected fish were proven both clinically and histopathologically.