Allobranchiibius huperziae gen. nov., sp. nov., a member of Dermacoccaceae isolated from the root of a medicinal plant Huperzia serrata (Thunb.)

Metallococcus carri gen. nov., sp. nov., a novel member of the family Dermacoccaceae isolated from an automotive air conditioning system

Strain designated DB0510^T was isolated from an automobile evaporator core collected in Korea. Cells are gram-stain-positive, aerobic, and coccoid. The strain grew at 15-45 ℃, pH 5.0-8.5 and 0-8.0% (w/v) NaCl. Growth occurs on R2A, trypticase soy agar, Luria-Bertani agar, and nutrient agar. Phylogenetic analysis showed that the strain belongs to the family Dermacoccaceae and strain DB0510^T was distinctly separated from validly named genera of this family. Signature nucleotides in 16S rRNA gene sequence revealed that the strain contained the Dermacoccaceae family-specific 16S rRNA signature nucleotides patterns. The major fatty acids were C_17:0 and C_17:1 cis-9. The only menaquinone was MK-8 (H₄). The polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, and two unidentified lipids. The diagnostic cell-wall amino acid at position 3 of the peptide subunit was found to be lysine. The cell-wall peptidoglycan contained alanine, aspartic acid, glutamic acid, glycine, lysine, and serine and thus the peptidoglycan type was concluded to be of A4α type with Lys-Gly-Ser-Asp interpeptide bridge. The genome size was 3.49 Mbp and G + C content of the genome DNA was 69.4 mol%. On the basis of the phenotypic, genomic, and chemotaxonomic characteristics, strain DB0510^T is considered to represent a novel genus and species within the family Dermacoccaceae, for which the name Metallococcus carri gen. nov., sp. nov. is proposed. The type strain of Metallococcus carri is DB0510^T (= KACC 19663 ^T = NBRC 113349 ^T).

Antimicrobial Activity Against Phytopathogens and Inhibitory Activity on Solanine in Potatoes of the Endophytic Bacteria Isolated From Potato Tubers

As an important global crop, the potato (Solanum tuberosum L.) contains the endotoxin solanine that leads to human poisoning and major economic losses. Poisoning symptoms and even acute poisoning may occur when the content of solanine in potatoes exceeds 200 mg/kg. In addition, potatoes are susceptible to some pathogenic bacteria, including Streptomyces scabies and Erwinia carotovora subsp. atroseptica (Van Hall) dye, which can cause potato scab and potato blackleg disease, respectively. In this study, 37 culturable endophytic bacteria strains were obtained from potato tubers based on the culture-dependent method. Results indicated that nine strains showed antimicrobial activity against at least one pathogen by antimicrobial activity screening and 23 strains showed inhibitory activity on solanine in potato tubers. Among them, strain P-NA2-14 (Bacillus megaterium NBRC 15308T, 99.31%) showed not only better antimicrobial activity against both the two indicator pathogens, but also the best inhibitory activity on solanine, which was proved to be a potential biocontrol bacterium. Meanwhile, the relationship between the distribution of the endophytic bacterial community and the content of solanine in potato tubers was studied by Illumina-based analysis, indicating that the distribution of the endophytic bacterial community was obviously influenced by the content of solanine. The results showed a new insight into the relationship between plant secondary metabolites and endophytic bacteria in potato tubers and provided potential new technical support for the biological control of potato storage.

Leekyejoonella antrihumi gen. nov., sp. nov., a new member of the family Dermacoccaceae isolated from a cave soil

A novel Gram-stain-positive, actinobacterial strain, designated C5-26^T, was isolated from soil from a natural cave in Jeju, Republic of Korea, and its taxonomic position was investigated using a polyphasic approach. The organism was aerobic, and cells were non-spore-forming, non-motile cocci that occurred singly, in pairs, in triplets, in tetrads, in short chains or in irregular clusters. Colonies of the cells were circular, convex, entire and white. The peptidoglycan type was A4α with an l-Ser-d-Asp interpeptide bridge. The whole-cell sugars comprised glucose, rhamnose, mannose, arabinose, galactose and ribose. The major menaquinone was MK-8(H₄). The polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unidentified phospholipid. The major fatty acids were iso-C_16 : 0 and iso-C_16 : 1 h. The size of the draft genome was 5.32 Mbp with depth of coverage of 161×. The G+C content of the genomic DNA was 67.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that the novel isolate belonged to the family Dermacoccaceae and formed a distinct subcluster at the base of the radiation of the genus Luteipulveratus. Highest sequence similarities of the novel isolate were found to the type strains of Luteipulveratus halotolerans (96.2 %), Branchiibius hedensis (95.4 %), Luteipulveratus mongoliensis (95.4 %) and Branchiibius cervicis (95.3 %). The whole genome-based phylogeny supported the novelty of the isolate at the genus level in the family Dermacoccaceae. On the basis of data from this polyphasic study, strain C5-26^T (=KCTC 39632^T=DSM 108676^T) represents a novel species of a new genus in the family Dermacoccaceae, for which the name Leekyejoonella antrihumi gen. nov., sp. nov. is proposed.

Production and Characterization of Extremophilic Proteinases From a New Enzyme Source, Barrientosiimonas sp. V9

Microbial proteases are widely used as commercial enzymes, which have an active role in several industrial processes. The aim of this study was to investigate the production and properties of extracellular proteases from Barrientosiimonas sp. strain V9. The cultivation conditions for protease production were studied using different carbon and nitrogen sources. Maximum protease production was obtained in medium containing 25 g L^-1 sucrose, 7 g L^-1 KNO₃, and initial pH 7.0 at 35 °C and 150 rpm during 72 h. Under these conditions, maximum proteolytic activity reached 1200 U mL^-1. The enzyme extract showed optimum activity at 60 °C, pH 9.0, and was stable from 30 to 50 °C within a pH range from 4.0 to 10.0 and NaCl concentration up to 2.5 M. The enzyme was stable in the presence of EDTA, urea, Triton X-100 and laundry detergent (sodium lauryl sulfate as main component). The addition of 1% sodium dodecyl sulfate, Tween-80, or Tween-20 increased the activity by 183% and 119% respectively, while 2-mercaptoethanol reduced the activity to 71%. Casein zymogram analysis revealed three hydrolysis zones suggesting that Barrientosiimonas sp. V9 expresses proteases with molecular weights about 60, 45, and 35 kDa, which were inhibited in the presence of phenylmethylsulfonyl fluoride. Barrientosiimonas sp. V9 produces halotolerant serine proteases with great biotechnological potential.

Desertihabitans aurantiacus gen. nov., sp. nov., a novel member of the family Propionibacteriaceae

The taxonomic position of an actinobacterium isolated from a desert soil sample collected from Badain Jaran Desert, designated as CPCC 204711^T, was established using a polyphasic approach. Cells of the isolate were Gram-staining-positive, aerobic, non-motile cocci. Good growth was observed at 28 °C (range 20-40 °C), pH 7.0 (range pH 6.0-8.0) and 0-1 % NaCl concentration (range 0-5 %, w/v). Galactose, arabinose and ribose were detected as the sugar compositions in the whole cell hydrolysates. The peptidoglycan type was A3gamma (ll-Dpm-Gly). MK-9(H4) was detected as the predominant menaquinone, and diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, several unidentified glycolipids, and one unidentified amino-glycolipid were detected as the major polar lipids. The predominant fatty acid was anteiso-C15 : 0. The genomic DNA G+C content was 73.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain CPCC 204711^T affiliated to the family Propionibacteriaceae, in which the strain formed a distinct phylogenetic lineage next to the genus Mariniluteicoccus, with the highest 16S rRNA gene sequence similarity of 96.0 % to Mariniluteicoccus endophyticus YIM 2617^T. Both phylogenetic analysis and phenotypic characteristics supported that strain CPCC 204711^T represents a novel species of a new genus in the family Propionibacteriaceae, for which the name Desertihabitans aurantiacus gen. nov., sp. nov. is proposed, with CPCC 204711^T (=KCTC 39977^T=DSM 105431^T) as the type strain.