Bhatt Hitarth B, Gohel Sangeeta D, Singh Satya P
UGC-CAS Department of Biosciences, Saurashtra University, Rajkot, Gujarat 360005 India.
3 Biotech. 2018 Jan;8(1):53. doi: 10.1007/s13205-017-1075-0. Epub 2018 Jan 4.
This report describes cultivation-dependent diversity, phylogeny and enzymatic potential of the haloalkaliphilic bacteria isolated from the unvegetated desert soil of yet unexplored, saline desert of Little Rann of Kutch (LRK), India. The LRK is a unique ecosystem displaying a combination of Dry Rann and Wet Rann. A total of 25 bacteria were isolated and characterized on the basis of colony morphology, biochemical profile, sugar utilization, secretion of the extracellular enzymes and antibiotic sensitivity. Further, the identification and phylogenetic relatedness of 23 bacteria were established by the analysis of 16S rRNA gene sequences. The phylogenetic analysis indicated that the isolates belong to the phylum , comprising low G + C, Gram-positive bacteria, with different genera: (~ 39%), (~ 30%), (~ 13%), (~ 13%), (~ 4%). Majority of the bacterial isolates produced proteases (30% isolates) followed by cellulases (24% isolates), CMCases (24% isolates) and amylases (20% isolates). , and predominantly produced hydrolases, while many produced multiple enzymes at high salinity and alkaline pH. Highest antibiotic resistance was observed against Ampicillin and Penicillin (32%) followed by Cefaclor (20%); Colistin, Cefoperazone and Cefotaxime (16%); Cefuroxime (12%); Gentamycin and Cefixime (8%); Erythromycin, Cefadroxil, Azithromycin, Co-trimoxazole, Amoxycillin, Norfloxacin, Cefpodoxime, Amikacin and Augmentin (4%). KJ1-10-99 and KJ1-10-93 representing < 97% of 16S rRNA gene sequence similarity belong to a novel lineage within the family . Comparison of the phenogram and phylogram revealed the contradiction of the phenogram pattern and the phylogenetic placement of the isolates. The isolates belonging to same species have shown considerable phenotypic variation. The study on the cultivable haloalkaliphilic bacteria of an unexplored enigmatic niche reflects ecological and biotechnological significance.
本报告描述了从印度库奇小盐沼（LRK）尚未开发的盐碱沙漠无植被荒漠土壤中分离出的嗜盐碱细菌的培养依赖性多样性、系统发育和酶学潜力。LRK是一个独特的生态系统，兼具干盐沼和湿盐沼的特征。基于菌落形态、生化特征、糖利用情况、细胞外酶分泌和抗生素敏感性，共分离并鉴定了25株细菌。此外，通过对16S rRNA基因序列的分析，确定了23株细菌的鉴定结果及其系统发育相关性。系统发育分析表明，这些分离株属于厚壁菌门，包括低G + C含量的革兰氏阳性菌，分属于不同的属：芽孢杆菌属（约39%）、葡萄球菌属（约30%）、微球菌属（约13%）、盐芽孢杆菌属（约13%）、嗜盐碱芽孢杆菌属（约4%）。大多数细菌分离株产生蛋白酶（30%的分离株），其次是纤维素酶（24%的分离株）、羧甲基纤维素酶（24%的分离株）和淀粉酶（20%的分离株）。芽孢杆菌属、葡萄球菌属和微球菌属主要产生水解酶，而许多菌株在高盐度和碱性pH条件下能产生多种酶。观察到对氨苄青霉素和青霉素的耐药性最高（32%），其次是头孢克洛（20%）；黏菌素、头孢哌酮和头孢噻肟（16%）；头孢呋辛（12%）；庆大霉素和头孢克肟（8%）；红霉素、头孢羟氨苄、阿奇霉素、复方新诺明、阿莫西林、诺氟沙星、头孢泊肟酯、阿米卡星和奥格门汀（4%）。代表16S rRNA基因序列相似度小于97%的KJ1-10-99和KJ1-10-93属于芽孢杆菌科内的一个新谱系。比较聚类图和系统发育树发现，聚类图模式与分离株的系统发育位置存在矛盾。属于同一物种的分离株表现出相当大的表型变异。对一个未开发神秘生态位中可培养嗜盐碱细菌的研究具有生态和生物技术意义。
