作　　者： (杨求华）; (郑乐云）; (黄种持）; (林琪）; (陆振）; (周宸）;

机构地区： 福建省水产研究所、福建省海洋生物增养殖与高值化利用重点实验室,福建厦门361013 汕头大学理学院,广东汕头515063

出　　处： 《中国水产科学》 2017年第5期1131-1140,共10页

摘　　要： 本研究分离了线纹海马(Hippocampus erectus)尾部溃烂症病原并对其理化、胞外酶和药敏特性进行了分析。结果显示,分离于患病海马肝脏的优势菌株HM-10为线纹海马尾部溃烂症病原菌,其对海马的半致死浓度(LD_(50))为1.51×10~6 CFU/g体重。API 20E理化分析显示,该菌精氨酸双水解酶阴性,赖氨酸、鸟氨酸脱羧酶阳性,L-阿拉伯糖、杏仁苷产酸。基于形态观察、理化指标对比,以及16S rRNA和看家基因(gyrB、rpoD、recA)序列分析结果,确定菌株HM-10为轮虫弧菌(Vibrio rotiferianus)。采用平板玻璃纸覆盖法制备该菌胞外产物(ECP),溶血及胞外酶活性分析结果显示,菌株HM-10的ECP对绵羊血有较强的溶血活性,同时具有蛋白酶、明胶酶、淀粉酶、脲酶活性,但不具有脂肪酶和卵磷脂酶活性。药敏分析结果显示,菌株HM-10对氨基糖苷类、青霉素类、头孢类、酰胺醇类及多肽类等17种药物敏感。本研究确定了线纹海马尾部溃烂症的病原菌为轮虫弧菌,结果对海马养殖中弧菌病的防治提供了参考资料。 Seahorses （Hippocampus spp.） are an iconic and ecologically important species worldwide. Within the past decade, overfishing and habitat destruction has drastically reduced wild seahorse populations. Seahorse aquaculture was thus developed as an important strategy to alleviate pressure on wild stock; however, these farms have been severely afflicted with tail rot, a serious disease in seahorses. To identify the agent causing tail-rot dis- ease in juvenile lined seahorses （Hippocampus erectus）, this study characterized the pathogen＇s physicochemical properties, extracellularproduct （ECP） activity, and drug susceptibility. One bacterial strain with superior growth （HM-10） was isolated from cultured liver samples of diseased juvenile lined seahorses. Healthy juvenile lined seahorses were then challenged with the strain through intraperitoneal injection. The results confirmed that HM-10 was pathogenic, causing tail-rot symptoms in challenged seahorses. The median lethal dose （LD50） of HM-10 was 1.51 × 10^6 cfu/g body weight. Results from the API 20E identification system showed that under L-arabinose and amygdalin-derived acid production, arginine dihydrolase, lysine decarboxylase, and ornithine decarboxylase ac- tivity in HM-10 were negative, positive, and positive, respectively. Morphological observation, biochemical char- acteristics, and genetic analysis identified HM-10 as Vibrio rotiferianus. The genetic analysis involved sequence detection of housekeeping gene 16S rRNA, including DNA gyrase subunit B gene （gyrB）, RNA polymerase sigma factor gene （rpoD）, DNA recombination protein gene （recA）, and concatenated gene sequences （4054 bp） of 16S rRNA-gyrB-rpoD-recA. The ECPs of HM-10 were extracted and their properties analyzed. The results showed that the ECPs had clear hemolytic activity in response to sheep red blood cells, while also exhibiting protease, gelatinase, urease, amylase, and hemolytic activity, but not lipase or lecithin activity. Susceptibility experiments invo

关 键 词： 线纹海马 尾部溃烂症 轮虫弧菌 病原鉴定 特性分析