Rafiq Muhammad, Hayat Muhammad, Anesio Alexandre M, Jamil Syed Umair Ullah, Hassan Noor, Shah Aamer Ali, Hasan Fariha
Department of Microbiology, Quaid-i-Azam University, Islamabad, Pakistan.
Department of Microbiology, Abdul Wali Khan University, Mardan, Pakistan.
PLoS One. 2017 Jul 26;12(7):e0178180. doi: 10.1371/journal.pone.0178180. eCollection 2017.
Cultureable bacterial diversity of previously unexplored Siachen glacier, Pakistan, was studied. Out of 50 isolates 33 (66%) were Gram negative and 17 (34%) Gram positive. About half of the isolates were pigment producers and were able to grow at 4-37°C. 16S rRNA gene sequences revealed Gram negative bacteria dominated by Proteobacteria (especially γ-proteobacteria and β-proteobacteria) and Flavobacteria. The genus Pseudomonas (51.51%, 17) was dominant among γ- proteobacteria. β-proteobacteria constituted 4 (12.12%) Alcaligenes and 4 (12.12%) Janthinobacterium strains. Among Gram positive bacteria, phylum Actinobacteria, Rhodococcus (23.52%, 4) and Arthrobacter (23.52%, 4) were the dominating genra. Other bacteria belonged to Phylum Firmicutes with representative genus Carnobacterium (11.76%, 2) and 4 isolates represented 4 genera Bacillus, Lysinibacillus, Staphylococcus and Planomicrobium. Most of the Gram negative bacteria were moderate halophiles, while most of the Gram positives were extreme halophiles and were able to grow up to 6.12 M of NaCl. More than 2/3 of the isolates showed antimicrobial activity against multidrug resistant S. aureus, E. coli, Klebsiella pneumonia, Enterococcus faecium, Candida albicans, Aspergillus flavus and Aspergillus fumigatus and ATCC strains. Gram positive bacteria (94.11%) were more resistant to heavy metals as compared to Gram negative (78.79%) and showed maximum tolerance against iron and least tolerance against mercury.
对巴基斯坦此前未被探索的锡亚琴冰川的可培养细菌多样性进行了研究。在50株分离菌株中，33株（66%）为革兰氏阴性菌，17株（34%）为革兰氏阳性菌。约一半的分离菌株可产生色素，且能够在4至37°C下生长。16S rRNA基因序列显示，革兰氏阴性菌以变形菌门（特别是γ-变形菌和β-变形菌）和黄杆菌为主。假单胞菌属（51.51%，17株）在γ-变形菌中占主导地位。β-变形菌包括4株（12.12%）产碱杆菌和4株（12.12%）詹氏菌属菌株。在革兰氏阳性菌中，放线菌门、红球菌属（23.52%，4株）和节杆菌属（23.52%，4株）是主要的属。其他细菌属于厚壁菌门，代表性属为肉杆菌属（11.76%，2株），另有4株分离菌株分别代表芽孢杆菌属、赖氨酸芽孢杆菌属、葡萄球菌属和扁平微杆菌属。大多数革兰氏阴性菌为中度嗜盐菌，而大多数革兰氏阳性菌为极端嗜盐菌，能够在高达6.12 M的氯化钠浓度下生长。超过2/3的分离菌株对多重耐药的金黄色葡萄球菌、大肠杆菌、肺炎克雷伯菌、粪肠球菌、白色念珠菌、黄曲霉和烟曲霉以及美国典型培养物保藏中心（ATCC）菌株具有抗菌活性。与革兰氏阴性菌（78.79%）相比，革兰氏阳性菌（94.11%）对重金属的耐受性更强，对铁的耐受性最强，对汞的耐受性最弱。
