Cryobacterium zhongshanensis sp. nov., an actinobacterium isolated from Antarctic soil

A Gram-staining-positive, heterotrophic, non-spore-forming, non-motile, rod-shaped, strain ZS14-85^T belonging to the genus Cryobacterium was isolated from soil in Antarctica. Growth was observed in the presence of 0-2% (w/v) NaCl, at pH 7.0-9.0 (optimum, pH 7.0) and 4-30 ℃ (optimum, 20 ℃). Phylogenetic analysis showed that strain ZS14-85^T formed a lineage in the genus Cryobacterium. The digital DNA-DNA hybridization (dDDH) values between strain ZS14-85^T and its close relatives Cryobacterium psychrotolerans CGMCC 1.5382^T, Cryobacterium soli MCCC 1K03549^T and Cryobacterium breve NBRC 113800^T were 22.5, 22.3 and 22.2%, respectively. Orthologous Average Nucleotide Identity (OrthoANI) scores between strain ZS14-85^T and C. psychrotolerans CGMCC 1.5382^T, C. breve NBRC 113800^T and C. soli MCCC 1K03549^T were 78.7, 78.1 and 77.7%, respectively. The polar lipids of strain ZS14-85^T were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), one unidentified glycolipid (GL) and two unidentified lipids (L). The major fatty acids were anteiso-C_15:0 (60.7%), iso-C_16:0 (17.0%) and anteiso-C_17:0 (15.2%). MK-10, MK-11 and MK-9 were the predominant respiratory menaquinones. Based on phenotypic, phylogenetic and genotypic data, a novel species, Cryobacterium zhongshanensis sp. nov. is proposed. The type strain is ZS14-85^T (= CCTCC AB 2019396^T = KCTC 49384^T).

Lacisediminihabitans changchengi sp. nov., an actinobacterium isolated from Antarctic swamplands mud

A Gram-staining-positive, heterotrophic, non-spore-forming, non-motile, short rod-shaped, strain G11-30^T belonging to the genus Lacisediminihabitans was isolated from a swampland mud in Antarctica. The strain was identified using a polyphasic taxonomic approach. The strain grew well on R2A agar media and formed no aerial mycelia and no diffusible pigments on any media tested. The chemotaxonomic results showed 2, 4-diaminobutyric acid (DAB) is the diagnostic diamino acid of the peptidoglycan. MK-10 was the predominant respiratory menaquinone. The major phospholipids were phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), unidentified lipid (L) and unidentified glycolipid (GL). The major fatty acids were anteiso-C15:0 (64.5%) and iso-C15:0 (18.7%). A phylogenetic tree based on 16S rRNA gene sequences showed that strain G11-30^T formed a lineage in the genus Lacisediminihabitans with the closest phylogenetic Lacisediminihabitans profunda CHu50b-6-2^T and Glaciihabitans tibetensis MP203^T (97.9%, 97.5% 16S rRNA gene sequence similarity). A phylogenomic tree based on genome sequence of G11-30^T, conferred by Type Strain Genome Server (TYGS), separated it from L. profunda CHu50b-6-2^T. Strain G11-30^T has a complete genome size of 2.59 Mb, with a G + C content of 66.2 mol%. The digital DNA-DNA hybridization (dDDH) score between strain G11-30^T and reference strains L. profunda CHu50b-6-2^T and G. tibetensis MP203^T were 20.1 and 20.3%, respectively. Concurrently, Average Nucleotide Identity (ANI) score between strain G11-30 ^T against. profunda CHu50b-6-2^T and G. tibetensis MP203^T were 76.2 and72.5%, respectively. Based on phenotypic, phylogenetic and genotypic data, a novel species, Lacisediminihabitans changchengi sp. nov. is proposed. The type strain is G11-30^T (= CCTCC AA 2019080^T = KCTC49359^T).

Aurantimicrobium photophilum sp. nov., a non-photosynthetic bacterium adjusting its metabolism to the diurnal light cycle and reclassification of Cryobacterium mesophilum as Terrimesophilobacter mesophilus gen. nov., comb. nov

The aerobic primarily chemoorganotrophic actinobacterial strain MWH-Mo1^T was isolated from a freshwater lake and is characterized by small cell lengths of less than 1 µm, small cell volumes of 0.05-0.06 µm³ (ultramicrobacterium), a small genome size of 1.75 Mbp and, at least for an actinobacterium, a low DNA G+C content of 54.6 mol%. Phylogenetic analyses based on concatenated amino acid sequences of 116 housekeeping genes suggested the type strain of Aurantimicrobium minutum affiliated with the family Microbacteriaceae as its closest described relative. Strain MWH-Mo1^T shares with the type strain of that species a 16S rRNA gene sequence similarity of 99.6 % but the genomes of the two strains share an average nucleotide identity of only 79.3 %. Strain MWH-Mo1^T is in many genomic, phenotypic and chemotaxonomic characteristics quite similar to the type strain of A. minutum. Previous intensive investigations revealed two unusual traits of strain MWH-Mo1^T. Although the strain is not known to be phototrophic, the metabolism is adjusted to the diurnal light cycle by up- and down-regulation of genes in light and darkness. This results in faster growth in the presence of light. Additionally, a cell size-independent protection against predation by bacterivorous flagellates, most likely mediated by a proteinaceous cell surface structure, was demonstrated. For the previously intensively investigated aerobic chemoorganotrophic actinobacterial strain MWH-Mo1^T (=CCUG 56426^T=DSM 107758^T), the establishment of the new species Aurantimicrobium photophilum sp. nov. is proposed.

Marisediminicola senii sp. nov. isolated from Queen Maud Land, Antarctica

A Gram-stain-variable, aerobic, orange pigmented, catalase-positive and oxidase-negative, cocci-shaped bacterium, designated SM7_A14^T, isolated from glacier fed sediment sample collected from the Queen Maud Land, near India's Maitri station in Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences revealed highest sequence similarity with Marisediminicola antarctica DSM 22350^T (97.3 %), demonstrated distinct phylogenetic positioning of strain SM7_A14^T within the genus Marisediminicola. Growth of strain SM7_A14^T occurs at 5-25 °C (optimum, 20 °C), pH 7.0-10 (optimum, pH 8.0) with 0-5 % NaCl (optimum 1-4 %, w/v). C_15 : 0 anteiso, C_17 : 0 anteiso, C_16 : 0 iso and C_15 : 1 anteiso A are the major fatty acids (>5 % of the total fatty acids). The polar lipid profile consisted of diphosphatidylglycerol and phosphatidylglycerol. The average nucleotide identity (ANI) and digital DNA-DNA hybridization values between SM7_A14^T and DSM 22350^T were 80.3 and 21.3 %, respectively. The genomic DNA G+C content of the strain SM7_A14^T was 68.5 %. Distinguishing characteristics based on the polyphasic analysis indicates strain SM7_A14^T as a novel species of genus Marisediminicola for which the name Marisediminicola senii sp. nov., is proposed. The type strain is SM7_A14^T (=MCC 4327^T=JCM 33936^T=LMG 31795^T).

Lacisediminihabitans profunda gen. nov., sp. nov., a member of the family Microbacteriaceae isolated from freshwater sediment

A novel Gram-stain-positive bacterial strain, CHu50b-6-2^T, was isolated from a 67-cm-long sediment core collected from the Daechung Reservoir at a water depth of 17 m, Daejeon, Republic of Korea. The cells of strain CHu50b-6-2^T were aerobic non-motile and formed yellow colonies on R2A agar. The phylogenetic analysis based on 16S rRNA gene sequencing indicated that the strain formed a separate lineage within the family Microbacteriaceae, exhibiting 98.0%, 97.7% and 97.6% 16S rRNA gene sequence similarities to Glaciihabitans tibetensis KCTC 29148^T, Frigoribacterium faeni KACC 20509^T and Lysinibacter cavernae DSM 27960^T, respectively. The phylogenetic trees revealed that strain CHu50b-6-2^T did not show a clear affiliation to any genus within the family Microbacteriaceae. The chemotaxonomic results showed B1α type peptidoglacan containg 2, 4-diaminobutyric acid (DAB) as the diagnostic diamino acid, MK-10 as the predominant respiratory menaquinone, diphosphatidylglycerol, phosphatidylglycerol, and an unidentified glycolipid as the major polar lipids, anteiso-C_15:0, iso-C_16:0, and anteiso-C_17:0 as the major fatty acids, and a DNA G + C content of 67.3 mol%. The combined genotypic and phenotypic data showed that strain CHu50b-6-2^T could be distinguished from all genera within the family Microbacteriaceae and represents a novel genus, Lacisediminihabitans gen. nov., with the name Lacisediminihabitans profunda sp. nov., in the family Microbacteriaceae. The type strain is CHu50b-6-2^T (= KCTC 49081^T = JCM 32673^T).

Quantification of residual antibiotics in cow manure being spread over agricultural land and assessment of their behavioral effects on antibiotic resistant bacteria

Antibiotic resistant bacteria (ARB) in livestock manure used as fertilizer and spread over agriculture land, may pose a threat to the health of humans. Considering this, the concentrations of tetracycline (TC), oxytetracycline (OTC), and sulfathiazole (STZ) in the surface soil were quantified using LC-MS. These antibiotics have been used in livestock and are found in fertilizer produced from livestock excretions. Species of ABR were identified using 16S rDNA. Soil samples were collected at depths of 0, 7, and 15 cm from farmland in Incheon (South Korea). In the surface soil, three compounds were detected: TC (17.74 μg/kg), OTC (0.78 μg/kg), and STZ (0.23 μg/kg). However, except for STZ, antibiotics were not detected in the deeper samples. Overall, TC can form a chelated complex with cations, which consequently enhances its adsorption to the organic matter and metals in soil. This property can significantly reduce the mobility of TC (to lower than that of STZ). The result of 16S rDNA gene analysis indicated that Pseudomonas spp., Arthrobacter spp., and Rhodococcus spp. showed persistent resistance to the three antibiotics tested. DNA quantification results revealed strong resistance of Pseudomonas spp. to STZ, whereas Arthrobacter spp. and Rhodococcus spp. had resistance to TC and OTC. Antibiotics biodegradation suggested ability of ARB to grow in soil samples in presence of residual antibiotics during 13 days incubation. The concentrations of STZ, TC, and OTC reduced as much as 23.53, 35.60 and 66.88%, respectively.

Frigoribacterium salinisoli sp. nov., isolated from saline soil, transfer of Frigoribacterium mesophilum to Parafrigoribacterium gen. nov. as Parafrigoribacterium mesophilum comb. nov

A Gram-stain-positive, short-rod, aerobic bacterium, designated as strain LAM9155T, was isolated from saline soil sample collected from Lingxian County, Shandong Province, PR China. The strain grew optimally at 25-30 °C, pH 7.0 and 0.5 % (w/v) NaCl. The 16S rRNA gene sequence analysis revealed that strain LAM9155T belonged to the genus Frigoribacterium and was closely related to Frigoribacteriumendophyticum EGI 6500707T (99.4 %), Frigoribacteriumfaeni 801T (98.6 %) and Frigoribacteriummesophilum MSL-08T (96.2 %). The DNA-DNA hybridization values between strain LAM9155T and F. endophyticum JCM 30093T and between strain LAM9155T and F. faeni DSM 10309T were 40.2±2.1 and 32.8±1.6 %, respectively. The major fatty acids of LAM9155T were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The cell-wall analysis showed the B-type peptidoglycan containing alanine, glutamate, glycine, serine and lysine and that the cell wall contained the sugars galactose and ribose. The genomic DNA G+C content of strain LAM9155T was 68.2 mol%. The predominant menaquinone was MK-9. The main polar lipids were diphosphatidylglycerol, phosphatidylglycerol, one unknown glycolipid and four unknown lipids. Based on the DNA-DNA hybridization and phenotypic, phylogenetic and chemotaxonomic properties, strain LAM9155T could be distinguished from the recognized species of the genus Frigoribacterium and was suggested to represent a novel species, for which the name Frigoribacterium salinisoli sp. nov. is proposed. The type strain is LAM9155T (=ACCC 19902T=JCM 30848T). Moreover, the transfer of F. mesophilum Dastager et al. 2008 to Parafrigoribacterium gen. nov. as Parafrigoribacterium mesophilum comb. nov. (type strain MSL-08T=DSM 19442T=KCTC 19311T) is also proposed.

Diversity of extremophilic bacteria in the sediment of high-altitude lakes located in the mountain desert of Ojos del Salado volcano, Dry-Andes

Ojos del Salado, the highest volcano on Earth is surrounded by a special mountain desert with extreme aridity, great daily temperature range, intense solar radiation, and permafrost from 5000 meters above sea level. Several saline lakes and permafrost derived high-altitude lakes can be found in this area, often surrounded by fumaroles and hot springs. The aim of this study was to gain information about the bacterial communities inhabiting the sediment of high-altitude lakes of the Ojos del Salado region located between 3770 and 6500 m. Altogether 11 sediment samples from 4 different altitudes were examined with 16S rRNA gene based denaturing gradient gel electrophoresis and clone libraries. Members of 17 phyla or candidate divisions were detected with the dominance of Proteobacteria, Acidobacteria, Actinobacteria and Bacteroidetes. The bacterial community composition was determined mainly by the altitude of the sampling sites; nevertheless, the extreme aridity and the active volcanism had a strong influence on it. Most of the sequences showed the highest relation to bacterial species or uncultured clones from similar extreme environments.

Lysinibacter cavernae gen. nov., sp. nov., a new member of the family Microbacteriaceae isolated from a karst cave

A Gram-stain-positive, aerobic, straight or slightly bent rod-shaped, non-motile, non-spore-forming bacterium, designated strain CC5-806T, was isolated from a soil sample collected from a wild karst cave in the Wulong region, Chongqing, PR China and examined using a polyphasic approach to clarify its taxonomic position. This bacterium did not produce substrate mycelium or aerial hyphae, and no diffusible pigments were observed on the media tested. Strain CC5-806T grew optimally without NaCl at 20 °C and at pH 7.0. Phylogenetic analysis, based on 16S rRNA gene sequences, indicated that strain CC5-806T belonged to the family Microbacteriaceae and showed the highest levels of 16S rRNA gene sequence similarities with Frigoribacterium endophyticum EGI 6500707T (97.56 %), Frigoribacterium faeni 801T (97.53 %) and Glaciihabitans tibetensis MP203T (97.42 %). Phylogenetic trees revealed that strain CC5-806T did not show a clear affiliation to any genus within the family Microbacteriaceae. The DNA G+C content of strain CC5-806T was 62.6 mol%. The cell-wall peptidoglycan contained l-lysine as a diagnostic diamino acid. The predominant menaquinones were MK-11, MK-10 and MK-9. Phosphatidylglycerol, diphosphatidylglycerol, an unidentified glycolipid, four unidentified phospholipids and other polar lipids were detected in the polar lipid extracts. The major fatty acids were anteiso-C15 : 0, iso-C16 : 0 and iso-C14 : 0. On the basis of the phylogenetic analysis, and phenotypic and chemotaxonomic characteristics, strain CC5-806T was distinguishable from phylogenetically related genera in the family Microbacteriaceae. It represents a novel species of a novel genus, for which the name Lysinibacter cavernae gen. nov., sp. nov. is proposed. The type strain is CC5-806T ( = DSM 27960T = CGMCC 1.14983T).

Aurantimicrobium minutum gen. nov., sp. nov., a novel ultramicrobacterium of the family Microbacteriaceae, isolated from river water

A Gram-stain-positive, aerobic, non-motile, curved (selenoid), rod-shaped actinobacterium, designated KNCT, was isolated from the 0.2 μm-filtrate of river water in western Japan. Cells of strain KNCT were ultramicrosized (0.04-0.05 μm3). The strain grew at 15-37 °C, with no observable growth at 10 °C or 40 °C. The pH range for growth was 7-9, with weaker growth at pH 10. Growth was impeded by the presence of NaCl at concentrations greater than 1 %. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain KNCT showed relatively high sequence similarity (97.2 %) to Alpinimonas psychrophila Cr8-25T in the family Microbacteriaceae. However, strain KNCT formed an independent cluster with cultured, but as-yet-unidentified, species and environmental clones on the phylogenetic tree. The major cellular fatty acids were anteiso-C15 : 0 (41.0 %), iso-C16 : 0 (21.8 %), C16 : 0 (18.0 %) and anteiso-C17 : 0 (12.9 %), and the major menaquinones were MK-11 (71.3 %) and MK-12 (13.6 %). The major polar lipids were phosphatidylglycerol and two unknown glycolipids. The cell-wall muramic acid acyl type was acetyl. The peptidoglycan was B-type, and contained 3-hydroxyglutamic acid, glutamic acid, aspartic acid, glycine, alanine and lysine, with the latter being the diagnostic diamino acid. The G+C content of the genome was unusually low for actinobacteria (52.1 mol%), compared with other genera in the family Microbacteriaceae. Based on the phenotypic characteristics and phylogenetic evidence, strain KNCT represents a novel species of a new genus within the family Microbacteriaceae, for which the name Aurantimicrobium minutum gen. nov., sp. nov. is proposed. The type strain of the type species is KNCT ( = NBRC 105389T = NCIMB 14875T).