Cellulomonas algicola sp. nov., an actinobacterium isolated from a freshwater alga.

An actinomycete strain, TKZ-21T, was isolated from a freshwater alga (Chetophoraceae) collected from the Takizawa River, Yamanashi, Japan, and examined using a polyphasic taxonomic approach. Cells were Gram-stain positive, aerobic, non-sporulating, motile, and coccoid or short rod-shaped. The strain grew in the presence of 0-4 % (w/v) NaCl, between pH 6-9.4, and over a temperature range of 15-40 °C, with optimum growth at 30 °C. The peptidoglycan type of strain TKZ-21T was A4ß, containing l-ornithine as diagnostic diamino acid and d-glutamic acid as the interpeptide bridge. The predominant menaquinone was MK-9(H4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol, ninhydrin-positive glycolipid, and unidentified phospholipids. The major cellular fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0, and the DNA G+C content was 75.6 mol%. On the basis of 16S rRNA gene sequence analysis, strain TKZ-21T was closely related to Cellulomonas fimi (98.5 % sequence similarity) and Cellulomonas biazotea (98.3 %). The genome orthoANI value between strain TKZ-21T and C. biazotea and C. fimi were 84.7 and 84.2 %, respectively. On the basis of fatty acid and MALDI-TOF MS profile analysis, phylogenetic analyses, genomic analysis, and phenotypic data, it is proposed that the isolate be classified as a representative of a novel species of the genus Cellulomonas, with the name Cellulomonas algicola sp. nov. The type strain is TKZ-21T (=NBRC 112905T=TBRC 8129T).

Aquabacterium tepidiphilum sp. nov., a moderately thermophilic bacterium isolated from a hot spring.

A Gram-stain-negative, aerobic, non-spore-forming and rod-shaped bacterium, designated YIM 730274T, was isolated from a sediment sample collected from a hot spring located in Tibet, PR China, and was characterized by using a polyphasic taxonomy approach. Cells were motile by means of a polar flagellum. The strain was oxidase- and catalase-positive, and contained polyalkanoates and polyphosphate as storage polymers. Growth occurred at 25-50 °C, at pH 6.0-8.5 and with 0.5-1.0 % NaCl. The major fatty acids (>10 %) were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The known polar lipids comprised of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine. The isoprenoid quinone was Q-8. The G+C content of genomic DNA was 70.7 mol%. The results of phylogenetic analyses based on 16S rRNA gene sequences indicated that the strain forms a monophyletic branch at the periphery of the evolutionary radiation occupied by the genus Aquabacterium in the class Betaproteobacteria. The most closely related phylogenetic neighbours were Aquabacterium limnoticumABP-4T (97.8 % 16S rRNA gene sequence identity) and Aquabacterium communeB8T (97.2 % 16SrRNA gene sequence identity). DNA-DNA relatedness values between YIM 730274T and A. limnoticum KCTC 23306T (46.4±0.4 %) and A. commune DSM 11901T (42.2±1.2 %) were well below the 70 % limit for species identification. YIM 730274T was distinguishable from other members of the genus Aquabacterium by the differences in phenotypic, chemotaxonomic and genotypic characteristics. YIM 730274T merits recognition as a representative of a novel species of the genus Aquabacterium. It is proposed that the isolate should be classified in the genus Aquabacterium as representing a novel species, Aquabacteriumtepidiphilum sp. nov. The type strain is YIM 730274T (=KCTC 52716T=CCTCC AB 2016295T).

Spartinivicinus ruber gen. nov., sp. nov., a Novel Marine Gammaproteobacterium Producing Heptylprodigiosin and Cycloheptylprodigiosin as Major Red Pigments.

The red pigment prodiginines are identified as bacterial secondary metabolites and display a wide range of bioactive properties. Here, a novel rose-red pigmented bacterium, designated strain S2-4-1HT, was isolated from coastal sediment of cordgrass Spartina alterniflora. Interestingly, it simultaneously produced heptylprodigiosin (C22H29N3O) and cycloheptylprodigiosin (C22H27N3O) as major red pigments, of which their chemical structures were established by liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR). Bioactive assays revealed that both heptylprodigiosin and cycloheptylprodigiosin had antibacterial and antifungal activities, and notably, cycloheptylprodigiosin showed stronger bioactivity than heptylprodigiosin. The complete genome of strain S2-4-1HT was determined to be 6,687,090 bp in length with a G + C content of 40.13 mol%, including a circular chromosome with a size of 6,361,125 bp and three plasmids with a size of 141,078, 102,423, and 82,464 bp, respectively. The biosynthetic gene cluster of two red pigments was predicted on a ∼41-kb gene fragment organized on the chromosome and displayed highly conserved features compared to several gammaproteobacterial species encoding the homologous genes. Finally, based on phenotypic, genotypic, and chemotaxonomic characteristics, strain S2-4-1HT represented a novel genus-level species named Spartinivicinus ruber gen. nov., sp. nov. (type strain S2-4-1HT = MCCC 1K03745T = KCTC 72148T). Our study provided a novel bacterial source and novel prodigiosin analogs as promising pharmaceuticals in biotechnological application.