Isoptericola croceus sp. nov., a novel actinobacterium isolated from saline-alkali soil.

A novel actinomycete, designated strain q2T, was isolated from the saline-alkaline soil, collected from Daqing, Heilongjiang province, China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain q2T belongs to the genus Isoptericola, and showed the highest sequence similarity to Isoptericola halotolerans KCTC 19046T (98.48%) and Isoptericola chiayiensis KCTC 19740T (98.13%), respectively. The average nucleotide identity values between strain q2T and other members of the genus Isoptericola were lower than 95% recommended for distinguishing novel prokaryotic species. Cells of strain q2T were Gram-staining-positive, aerobic, non-motile, rod-shaped and non-spore-forming. Colonies of strain q2T were golden-yellow pigmented, tidy edged and smooth surfaced. Growth occurred at 15-37 °C (optimum, 29 °C), pH 7.0-10.0 (optimum, pH 8.0). The predominant respiratory quinones were MK-9(H4) and MK-9(H2). The main detected polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannoside. The peptidoglycan compositions were L-alanine, D-aspartic, L-glutamic acid and L-lysine (type A4α). The major cellular fatty acids (> 10%) were anteiso-C15:0, iso-C15:0, and anteiso-C17:0. The G+C content of the genomic DNA was determined to be 69.7%. Based on the phenotypic, physiological, genotypic, and phylogenetic data, strain q2T represents a novel species of the genus Isoptericola, for which the name Isoptericola croceus sp. nov. is proposed. The type strain is q2T (= GDMCC 1.2923T = KCTC 49759T).

Thermalbibacter longus gen. nov., sp. nov., isolated from a hot spring.

An isolate, designated CFH 74404T, was recovered from a hot spring in Tengchong, Yunnan province, PR China. Phylogenetic analysis indicated that the isolate belongs to the family Thermomicrobiaceae and showed the highest 16S rRNA gene sequence similarity to Thermorudis peleae KI4T (93.6 %), Thermorudis pharmacophila WKT50.2T (93.1 %), Thermomicrobium roseum DSM 5159T (92.0 %) and Thermomicrobium carboxidum KI3T (91.7 %). The average amino acid identity and average nucleotide identity values between strain CFH 74404T and the closest relatives were 42.0-75.9 % and 67.0-77.3 %, respectively. Cells of strain CFH 74404T stained Gram-positive and were aerobic, non-motile and short rod-shaped. Growth occurred at 20-65 °C (optimum, 55 °C), pH 6.0-8.0 (optimum, pH 7.0) and with up to 2.0 % (w/v) NaCl (optimum 0-1.0 %, w/v). The predominant respiratory quinone was MK-8. The major fatty acids (>10 %) were C18 : 0 (50.8 %) and C20 : 0 (16.8 %). The polar lipid profile of strain CFH 74404T included diphosphatidylglycerol, four unidentified phosphoglycolipids, phosphatidylinositol and three unidentified glycolipids. The G+C content of the genomic DNA was determined to be 67.1 mol% based on the draft genome sequence. On the basis of phenotypic, phylogenetic and genotypic analyses, it is concluded that strain CFH 74404T represents a new species of a novel genus Thermalbibacter of the family Thermomicrobiaceae, for which the name Thermalbibacter longus gen. nov., sp. nov. is proposed. The type strain is CFH 74404T (=KCTC 62930T=CGMCC 1.61585T).

Clostridium caldaquaticum sp. nov., a thermophilic bacterium isolated from a hot spring sediment.

A novel anaerobic bacterium, designated SYSU GA19001T, was isolated from a hot spring sediment sample. Phylogenetic analysis indicated that the isolate belongs to the genus Clostridium, and showed the highest sequence similarity to Clostridium swellfunianum CICC 10730T (96.63 %) and Clostridium prolinivorans PYR-10T (96.11 %). Cells of strain SYSU GA19001T were Gram-stain-positive, spore-forming, rod-shaped (0.6-0.8×2.6-4.0 µm) and motile. Growth was observed at pH 5.0-9.0 (optimum, pH 7.0), 37-55 °C (optimum, 45 °C) and in NaCl concentrations of 0-2.0 % (optimum, 0 %). The genomic DNA G+C content was 31.62 %. The major cellular fatty acids of strain SYSU GA19001T were C14 : 0, iso-C15 : 0, C16 : 0 and summed feature 8. The prominent polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol. Meso-diaminopimelic acid was the diamino acid in peptidoglycan. Based on the results of phylogenetic, chemotaxonomic and phenotypic analyses, strain SYSU GA19001T represents a novel species of the genus Clostridium, for which the name Clostridium caldaquaticum sp. nov. is proposed. The type strain of the proposed novel species is SYSU GA19001T (=NBRC 115040T= CGMCC 1.17864T).

Acuminatums E and F, two new cyclic lipopeptides from Fusarium lateritium HU0053 and their antifungal activity.

Two new cyclic lipopeptides, acuminatums E (1) and F (2), together with four known cyclic lipopeptides, acuminatums A-D (3-6) were isolated from the corn culture of endophytic Fusarium lateritium HU0053. Their structures were elucidated by spectroscopic and advanced Marfey's amino acid analysis. All compounds were found to exhibit antifungal activities against Penicillium digitatum. Acuminatum F (2), a new cyclic lipopeptide containing an unusual 3, 4-dihydroxy-phenylalanine unit exhibited the strongest antifungal activities with inhibition zone of 6.5 mm at the dose of 6.25 µg. Therefore, acuminatum F might be a potential environmental-friendly preservative for citrus fruits.

Description of five novel thermophilic species of the genus Thermus: Thermus hydrothermalis sp. nov., Thermus neutrinimicus sp. nov., Thermus thalpophilus sp. nov., Thermus albus sp. nov., and Thermus altitudinis sp. nov., isolated from hot spring sediments.

Biological denitrification is a significant process in nitrogen biogeochemical cycle of terrestrial geothermal environments, and Thermus species have been shown to be crucial heterotrophic denitrifier in hydrothermal system. Five Gram-stain negative, aerobic and rod-shaped thermophilic bacterial strains were isolated from hot spring sediments in Tibet, China. Phylogenetic analysis based on 16S rRNA gene and whole genome sequences indicated that these isolates should be assigned to the genus Thermus and were most closely related to Thermus caldifontis YIM 73026T, and Thermus brockianus YS38T. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the five strains and the type strains of the genus Thermus were lower than the threshold values (95% and 70%, respectively) recommended for bacterial species, which clearly distinguished the five isolates from other species of the genus Thermus and indicated that they represent independent species. Colonies are circular, convex, non-transparent. Cell growth occurred at 37-80 °C (optimum, 60-65 °C), pH 6.0-8.0 (optimum, pH 7.0) and with 0-2.0% (w/v) NaCl (optimum, 0-0.5%). Denitrification genes (narG, nirK, nirS, and norB genes) detected in their genomes indicated their potential function in nitrogen metabolism. The obtained results combined with those of morphological, physiological, and chemotaxonomic characteristics, including the menaquinones, polar lipids, and cellular fatty acids showed that the isolates are proposed as representing five novel species of the genus Thermus, which are proposed as Thermus hydrothermalis sp. nov. SYSU G00291T, Thermus neutrinimicus sp. nov. SYSU G00388T, Thermus thalpophilus sp. nov. SYSU G00506T, Thermus albus sp. nov. SYSU G00608T, Thermus altitudinis sp. nov. SYSU G00630T.

Oceanobacillus saliphilus sp. nov., Isolated from Saline-Alkali Soil in Heilongjiang Province, China.

A novel bacterium, designated strain APA_H-1(4)T, was isolated from the saline-alkaline soil, Zhaodong, Heilongjiang Province, China. Phenotypic and chemotaxonomic analyses, and whole-genome sequencing were used to determine the taxonomic position of the strain. Phylogenetic analysis indicated that the isolate belongs to the genus Oceanobacillus, and showed the highest sequence similarity to O. damuensis KCTC 33146T (98.35%, similarity) and 'O. massiliensis' DSM 24644 (98.32%). The average nucleotide identity values between strain APA_H-1(4)T and other members of the genus Oceanobacillus were lower than 82% recommended for distinguishing novel prokaryotic species. The digital DNA-DNA hybridization values of strain APA_H-1(4)T with O. damuensis KCTC 33146T and 'O. massiliensis' DSM 24644 were 13.60 and 17.60%, respectively. Cells of strain APA_H-1(4)T were Gram-staining positive, motile, aerobic, spore-forming rods (0.5-0.7 × 1.8-2.6 µm) with flagella. The growth was found to occur optimally at 37 °C. The whole-cell hydrolysate contained meso-diaminopimelic acid as the diagnostic cell wall diamino acid. The main detected polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, an unidentified phospholipid and an unidentified polar lipid. The predominant respiratory quinone was identified as menaquinone-7 (MK-7). The major cellular fatty acid (>10%) was anteiso-C15:0. The G + C content of the genomic DNA was determined to be 38.4% based on the draft genome sequence. Based on the comparative analysis of polyphasic taxonomic data, strain APA_H-1(4)T represents a novel species of the genus Oceanobacillus, for which the name Oceanobacillus saliphilus sp. nov. is proposed. The type strain is APA_H-1(4)T (=GDMCC 1.2239T = KCTC 43254T).

Qipengyuania thermophila sp. nov., isolated from a Chinese hot spring.

A novel Gram-stain-negative, non-motile, short rod-shaped and aerobic bacterial strain, designated as CFH 74456 T, was isolated from sediment of a hot spring, Tengchong, Yunnan Province, south-western China. Growth occurred at 20-53 ºC (optimum 45 ºC), pH 7.0-9.0 (optimum pH 8.0) and up to 2.0% (w/v) NaCl (optimum 0-1.0%, w/v). The predominant respiratory quinone was ubiquinone 10 (Q-10). The major fatty acids (> 10%) were C17:1 ω6c (17.9%) and summed feature 8 (38.6%). The polar lipid profile of strain CFH 74456 T was identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid, three unidentified glycolipids and three unidentified polar lipids. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain CFH 74456 T belongs to the genus Qipengyuania, and was most closely related to Qipengyuania sediminis CGMCC 1.12928 T (95.7%). The draft genome size of the isolate was 2.29 Mb with G + C content of 68.5%. The amino acid identity, average nucleotide identity and the digital DNA-DNA hybridization values between strain CFH 74456 T and the closest relatives ranged from 67.0 to 67.9%, 73.0 to 74.2% and 18.2-19.3%, respectively. On the basis of phenotypic, phylogenetic and genotypic analyses, it is concluded that strain CFH 74456 T represents a new species of the genus Qipengyuania, for which the name Qipengyuania thermophila sp. nov. is proposed. The type strain is CFH 74456 T (= KCTC 62921 T = CCTCC AB 2018237 T).