Institute for Water and Wastewater Technology, Durban University of Technology, Durban, 4001, South Africa.
Department of Biotechnology and Food Technology, Durban University of Technology, Durban, 4001, South Africa.
Microbiol Res. 2018 Jun;211:47-56. doi: 10.1016/j.micres.2018.04.001. Epub 2018 Apr 3.
A novel halotolerant species of cyanobacterium of the order Chroococcales was isolated from hypersaline estuary in Kwa-Zulu Natal, South Africa. A comprehensive polyphasic approach viz., cell morphology, pigment composition and complete genome sequence analysis was conducted to elucidate the taxonomic position of the isolated strain. The blue-green oval to rod-shaped cells were 14-18 μm in size, and contained a high amount of phycocyanin pigments. The strain was moderate thermotolerant/alkalitolerant halophile with the optimum conditions for growth at 35 °C, pH 8.5 and 120 g/l of NaCl. Based on 16S rRNA gene sequence phylogeny, the strain was related to members of the 'Euhalothece' subcluster (99%). The whole genome sequence was determined, and the annotated genes showed a 90% sequence similarity to the gas-vacuolate, spindle-shaped Dactylococcopsis salina PCC 8305. The size of the genome was determined to be 5,113,178 bp and contained 4332 protein-coding genes and 69 RNA genes with a G + C content of 46.7%. Genes encoding osmoregulation, oxidative stress, heat shock, persister cells, and UV-absorbing secondary metabolites, among others, were identified. Based on the phylogenetic analysis of the 16S rRNA gene sequences, physiological data, pigment compositions and genomic data, the strain is considered to represent a novel species of Euhalothece.
从南非夸祖鲁-纳塔尔省的高盐河口分离到一种新型耐盐蓝藻，属于色球藻目。采用细胞形态、色素组成和全基因组序列分析等综合多相方法，阐明了分离株的分类地位。蓝色椭圆形到杆状细胞大小为 14-18μm，含有大量的藻蓝蛋白色素。该菌株为中度耐热/耐碱嗜盐菌，最适生长条件为 35°C、pH8.5 和 120g/lNaCl。基于 16S rRNA 基因序列系统发育，该菌株与“Euhalothece”亚群的成员有关（99%）。全基因组序列已确定，注释基因与气液空泡、纺锤形的 Dactylococcopsis salina PCC 8305 的序列相似度为 90%。基因组大小确定为 5,113,178bp，包含 4332 个编码蛋白的基因和 69 个 RNA 基因，G+C 含量为 46.7%。鉴定出了与渗透压调节、氧化应激、热休克、持久细胞和紫外线吸收次生代谢物等相关的基因。基于 16S rRNA 基因序列、生理数据、色素组成和基因组数据的系统发育分析，该菌株被认为代表了 Euhalothece 的一个新种。
