Rathore Dalip Singh, Sheikh Mahejbin A, Gohel Sangeeta D, Singh Satya P
Department of Biosciences, UGC Centre for Advanced Studies (CAS), Saurashtra University, Rajkot, Gujarat, India.
Curr Microbiol. 2021 Apr;78(4):1377-1387. doi: 10.1007/s00284-021-02420-0. Epub 2021 Mar 1.
This study deals with the genetic and phenotypic heterogeneity of the marine Nocardiopsis alba strains isolated during pre-monsoon, monsoon and post-monsoon seasons. The isolates were characterized for their morphological and biochemical attributes, growth media preferences, antibiotic susceptibility and extracellular enzyme secretion. Nocardiopsis alba strains were assessed against 12 different antibiotics, and the responses were expressed in terms of the multiple antibiotic resistance (MAR) number. The majority of the strains produced multiple extracellular enzymes: proteases, amylases and lipases. Further, the strains were characterized on the basis of 16S rRNA gene sequencing and the majority were identified as Nocardiopsis alba along with few strains of Streptomyces lopnurensis, Nocardiopsis synnemataformans and Nocardiopsis dassonvillei. Neighbor-joining (NJ) phylogenetic tree suggested variation among the genetically similar Nocardiopsis alba species. The study establishes significant heterogeneity with respect to genetic and phenotypic characteristics of the strains of Nocardiopsis alba. Phylogenetic tree and phenogram-based comparison reflect the heterogeneity in terms of different clustering patterns of the strains. Further, the whole genome sequence data available in the literature also confirm the observed heterogeneity. Nocardiopsis alba strains displayed a relatively regressive pattern of dependence on the environmental factors based on the canonical correspondence analysis plot. The study represents cultivation, characterization, phylogenetic analysis and enzymatic potential of the Nocardiopsis alba species of seawater origin.
本研究探讨了在季风前、季风期和季风后季节分离出的海洋白色诺卡氏菌菌株的遗传和表型异质性。对分离菌株的形态和生化特性、生长培养基偏好、抗生素敏感性及胞外酶分泌进行了表征。对白色诺卡氏菌菌株进行了12种不同抗生素的测试，并以多重抗生素抗性（MAR）数值表示反应情况。大多数菌株产生多种胞外酶：蛋白酶、淀粉酶和脂肪酶。此外，基于16S rRNA基因测序对菌株进行了表征，大多数菌株被鉴定为白色诺卡氏菌，还有少数菌株为罗布泊链霉菌、交织诺卡氏菌和达松维尔诺卡氏菌。邻接法（NJ）系统发育树表明，遗传相似的白色诺卡氏菌物种之间存在差异。该研究证实了白色诺卡氏菌菌株在遗传和表型特征方面存在显著异质性。基于系统发育树和表型图的比较反映了菌株不同聚类模式方面的异质性。此外，文献中可用的全基因组序列数据也证实了所观察到的异质性。基于典范对应分析图，白色诺卡氏菌菌株对环境因子的依赖呈现出相对递减的模式。该研究展示了海水来源的白色诺卡氏菌物种的培养、表征、系统发育分析及酶学潜力。
