Dept. of Aquatic Health and Environment, College of Fisheries, Central Agricultural University (Imphal), Lembucherra, Tripura, 799210, India.
Dept. of Fish Genetics and Breeding, College of Fisheries, Central Agricultural University (Imphal), Lembucherra, Tripura, 799210, India.
Probiotics Antimicrob Proteins. 2021 Dec;13(6):1572-1584. doi: 10.1007/s12602-021-09788-2. Epub 2021 Apr 26.
In this study, a bacterial strain COFCAU_P1, isolated from the digestive tract of a freshwater teleost rohu (Labeo rohita), was identified as Bacillus amyloliquefaciens using 16S rRNA gene sequence analysis combined with amplification of species-specific BamHI and barnase genes. The probiotic potential of the strain was evaluated using an array of in vitro tests along with safety and genetic analyses. The isolate showed potent antimicrobial response against several fish pathogenic bacteria, survived a wide pH range (2-9), and was resistant up to 10% bile salt concentration. With regard to the in vitro adhesion properties, the strain showed significantly high in vitro adhesion to mucus, auto and co-aggregation capacity, and cell surface hydrophobicity. The strain was non-haemolytic, able to produce extracellular enzymes, viz., proteinase, amylase, lipase, and cellulase, and showed significant free radical scavenging activity. A challenge study in rohu revealed the strain COFCAU_P1 as non-pathogenic. The presence of putative probiotic marker genes including 2, 3-bisphosphoglycerate-independent phosphoglycerate mutase, arginine/ornithine antiporter ArcD, choloylglycine hydrolase, LuxS, and E1 β-subunit of the pyruvate dehydrogenase complex was confirmed by PCR, suggesting the molecular basis of the probiotic-specific functional attributes of the isolate. In conclusion, the in vitro and genetic approaches enabled the identification of a potential probiotic from autochthonous source with a potential of its utilization in the aquaculture industry.
在这项研究中，从淡水罗非鱼（Labeo rohita）消化道中分离出的一株细菌 COFCAU_P1，通过 16S rRNA 基因序列分析结合扩增物种特异性 BamHI 和 barnase 基因，被鉴定为解淀粉芽孢杆菌。通过一系列体外试验以及安全性和遗传分析评估了该菌株的益生菌潜力。该分离株对几种鱼类致病菌表现出强烈的抗菌反应，能够在宽 pH 范围（2-9）下生存，并能耐受高达 10%的胆汁盐浓度。关于体外黏附特性，该菌株表现出对黏液、自体和共聚集能力以及细胞表面疏水性的显著高体外黏附能力。该菌株不溶血，能够产生胞外酶，如蛋白酶、淀粉酶、脂肪酶和纤维素酶，并具有显著的自由基清除活性。在罗非鱼中的挑战研究表明，菌株 COFCAU_P1 无致病性。存在推定的益生菌标记基因，包括 2,3-二磷酸甘油酸独立磷酸甘油酸变位酶、精氨酸/鸟氨酸反向转运蛋白 ArcD、胆酰甘氨酸水解酶、LuxS 和丙酮酸脱氢酶复合物的 E1β亚基，通过 PCR 得到证实，表明了该分离株益生菌特异性功能属性的分子基础。总之，体外和遗传方法鉴定了一种具有潜在益生菌特性的本土来源的潜在益生菌，有望在水产养殖行业中得到应用。
