Aquiflexum lacus sp. nov., isolated from a lake sediment sample

Psychromicrobium Xiongbiense sp. nov., an Actinobacterium Isolated from Forest Soil

A novel Gram-stain-positive, oval-shaped, and non-flagellated bacterial strain YIM S02556T was isolated from forest soil in Xiongbi Town, Shizong County, Qujing City, Yunnan Province, southwestern China. The strain exhibited high pairwise 16 S rRNA gene sequence similarity with Psychromicrobium lacuslunae (97.3%) and Psychromicrobium silvestre (96.3%). Strain YIM S02556T exhibited an average nucleotide identity (ANI) of 72.5% with P. lacuslunae IHBB 11,108T and 72.8% ANI with P. silvestre AK 20-18T. The digital DNA-DNA hybridization (dDDH) value between strain YIM S02556T and P. lacuslunae IHBB 11,108T was 20.2%, while with P. silvestre AK 20-18T, the dDDH value was 20.8%. Strain YIM S02556T exhibited optimal growth at 28 °C, pH 7.0, without NaCl. Growth occurred within 10-37 ℃, pH 5.0-8.0, and in the presence of up to 5% w/v NaCl concentration. The genome size was 3.1 Mbp with 64.2% G + C content. The predominant menaquinone was MK-8(H4). The major cellular fatty acid was anteiso-C15:0. Based on the polyphasic analysis, strain YIM S02556T (= KCTC 49,805T = CCTCC AB2020166T) represents a novel Psychromicrobium species in which the name Psychromicrobium xiongbiense sp.nov. was proposed.

Shiella aurantiaca gen. nov., sp. nov., a novel bacterium isolated from activated sludge, and proposal of Shiellaceae fam. nov

A novel Gram-stain-negative, long rod-shaped, aerobic, non-motile, non-spore-forming and orange-pigmented bacterium, designated LB-30T, was isolated from activated sludge. Growth was observed at 15-40 °C (optimum 30 °C), pH 6.0-9.0 (optimum 7.0) and salinities of 0-3.0 % (w/v; optimum 2.0 %). LB-30T showed less than 89.9 % sequence similarities to the recognized taxa of the order Cytophagales. The results of phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic tree indicated that LB-30T formed a distinct lineage within the order Cytophagales. The average amino acid identity (AAI) values between LB-30T and members of the related families Cyclobacteriaceae, Fulvivirgaceae, Roseivirgaceae, Reichenbachiellaceae, Cesiribacteraceae, Cytophagaceae and Hymenobacteraceae in the order Cytophagales were 50.5-54.6 %. The sole respiratory quinone of LB-31T was menaquinone 7 (MK-7). The major polar lipids were phosphatidylethanolamine, aminolipid and four unidentified lipids. The major fatty acids were iso-C15 : 0, iso-C15 : 1G and iso-C17 : 0 3-OH. The DNA G+C content was 43.8 mol%, calculated from the genome sequence. On the basis of differences in the phenotypic, physiological and biochemical characteristics, and distinct phylogenetic relationships, strain LB-30T is proposed to represent a novel species in a novel genus for which the name Shiella aurantiaca gen. nov., sp. nov is proposed, within a novel family Shiellaceae fam. nov. of the order Cytophagales. The type strain is LB-30T (=GDMCC 1.3629T= KCTC 92689T).

Proposal to reclassify Aquiflexum aquatile into a novel genus as Cognataquiflexum aquatile gen. nov., comb. nov., and description of Cognataquiflexum nitidum sp. nov. and Cognataquiflexum rubidum sp. nov., isolated from freshwater lakes on the Tibetan Plateau

Thousands of lakes harbouring different characteristics (pH, salinity, temperature) are located on the Tibetan Plateau, and the mining of microbial resources inhabited in these lakes has great value. Two Gram-stain-negative, aerobic, rod-shaped, non-motile strains (LQ15W^T and AIY15W^T) were isolated from freshwater lakes on the Tibetan Plateau. Comparisons based on the 16S rRNA gene sequences showed that both strains LQ15W^T and AIY15W^T share 16S rRNA gene sequence similarities 98.4 % with Aquiflexum aquatile Z0201^T, but only about 95.0 % with Aquiflexum balticum DSM 16537^T. The 16S rRNA gene sequence similarity between strains LQ15W^T and AIY15W^T was 98.9 %. The phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that strains LQ15W^T and AIY15W^T take A. aquatile Z0201^T as their closest neighbour and these three strains form a tight cluster. In the phylogenomic tree, the genus Aquiflexum was splited into two clusters by Mariniradius saccharolyticus. Strains LQ15W^T, AIY15W^T and A. aquatile Z0201^T still formed a close cluster, and A. balticum DSM 16537^T and Aquiflexum lacus CUG 91378^T formed another cluster. The calculated OrthoANIu, average amino acid identity and digital DNA-DNA hybridization values among strains LQ15W^T, AIY15W^T, A. aquatile Z0201^T, A. balticum DSM 16537^T and A. lacus CUG 91378^T were less than 91.0, 92.9 and 42.1 %, respectively. The major respiratory quinones of both strains LQ15W^T and AIY15W^T were MK-7 (32 %) and MK-8 (68 %), and their major fatty acids were iso-C_15 : 0, C_18 : 1  ω9c, summed feature 3 and summed feature 9. The predominant polar lipids of both strains were phosphatidylethanolamine, unidentified aminophospholipids, unidentified phospholipids and lipids. Strain AIY15W^T also contained phosphatidylglycerol and unidentified glycolipid. Considering the distinct phylogenetic relationships and chemotaxonomic characteristics between strains A. aquatile Z0201^T and A. balticum DSM 16537^T, it is proposed to reclassify A. aquatile into a novel genus Cognataquiflexum gen. nov. as Cognataquiflexum aquatile comb. nov., and strains LQ15W^T and AIY15W^T should represent two independent novel species of the genus Cognataquiflexum, for which the names Cognataquiflexum nitidum sp. nov. (type strain: LQ15W^T=CICC 24711^T=JCM 34222^T) and Cognataquiflexum rubidum sp. nov. (type strain: AIY15W^T=CICC 24708^T=JCM 34612^T) are proposed.