Arthrobacter antarcticus sp. nov., isolated from an Antarctic marine sediment

Arthrobacter vasquezii sp. nov., isolated from a soil sample from Union Glacier, Antarctica

A Gram-stain-positive, catalase-positive, non-motile bacteria, with a rod-coccus cycle (designated as EH-1B-1T) was isolated from a soil sample from Union Glacier in Ellsworth Mountains, Antarctica. Strain EH-1B-1T had an optimal growth temperature of 28 °C and grew at pH 7-10. The major cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0, C16 : 0 and anteiso-C17 : 0. The G+C content based on the whole genome sequence was 63.1 mol%. Strain EH-1B-1T was most closely related to members of the genus Arthrobacter, namely Arthrobacter subterraneus and Arthrobacter tumbae. The strain grew on tryptic soy agar, Reasoner's 2A agar, lysogeny broth agar and nutrient agar. The average nucleotide identity and digital DNA-DNA hybridization values between strain EH-1B-1T and its closest reference type strains ranged from 78 to 88 % and from 20.9 to 36.3 %, respectively. Based on phenotypic, chemotypic and genotypic evidence, it is proposed that strain EH-1B-1T represents a novel species of Arthrobacter, for which the name Arthrobacter vasquezii sp. nov. is proposed, with strain EH-1B-1T (RGM 3386T=LMG 32961T) as the type strain.

Paeniglutamicibacter quisquiliarum sp. nov., isolated from midden soil waste

A Gram-stain-positive, irregular short-rod and non-motile bacterium, designated strain ABSL32-1^T, was isolated from a soil sample collected from the Suphan Buri municipal solid waste disposal area. According to the results of a polyphasic taxonomic study, a novel species belonging to the genus Paeniglutamicibacter was described. Strain ABSL32-1^T grew optimally at 20-25 °C and at pH 6.0-8.0 in the presence of 1 % (w/v) NaCl. The whole-cell sugars were ribose, mannose and glucose. The peptidoglycan structure contained A4α peptidoglycan (Lys-Glu; A11.54). The polar lipids contained digalactosyldiacylglycerol, diphosphatidylglycerol, phosphatidylglycerol, unidentified phospholipids and two unidentified lipids. The major menaquinones were MK-9 and MK-10. The major cellular fatty acid was anteiso-C_15 : 0 (70.1 %). Based on 16S rRNA gene sequence analysis, strain ABSL32-1^T showed the highest similarity to Paeniglutamicibacter sulfureus DSM 20167^T (99.5 %), followed by Paeniglutamicibacter antarcticus SPC26^T (99.0 %) and Paeniglutamicibacter psychrophenolicus AG31^T (98.8 %). The genome of strain ABSL32-1^T is 4.4 Mbp with a DNA G+C content of 66.0 mol%. The average nucleotide identity values between strain ABSL32-1^T and the type strains P. sulfureus DSM20167^T, P. antarcticus SPC26^T and P. psychrophenolicus AG31^T were 86.6, 74.7 and 83.6 %, respectively. On the basis of phenotypic, chemotaxonomic and genotypic properties, strain ABSL32-1^T is proposed to represent a novel species to be named Paeniglutamicibacter quisquiliarum sp. nov. The type strain is ABSL32-1^T (=TBRC 14976^T=NBRC 115252^T).

Arthrobacter terrae sp. nov., a psychrophilic actinobacterium with multi copies of capA gene isolated from Antarctic soil

A Gram-staining-positive, non-spore-forming, non-flagellated, ellipsoidal, strain Z1-20 ^T belonging to the genus Arthrobacter was isolated from a soil sample collected from the Zhongshan station, Antarctic. Phylogenetic analysis of the 16S rRNA gene sequences and phylogenetic analysis revealed that strain Z1-20 ^T formed a unique single cluster in the genus Arthrobacter and shared high 16S rRNA sequence similarities of 97.1% and 96.9% with A. glacialis HLT2-12-2 ^T and A. psychrochitiniphilus GP3^T, respectively. Values of Digital DNA-DNA hybridization (dDDH) between strain Z1-20 ^T against A. glacialis HLT2-12-2 ^T and A. psychrochitiniphilus GP3^T were 20.3% and 13.8%, respectively. Average nucleotide identity (ANI) score between strain Z1-20 ^T against A. glacialis HLT2-12-2 ^T and A. psychrochitiniphilus GP3^T were 72.5% and 72.1%, respectively. Genes for the synthesis of the osmoprotectant glycine betaine and higher copies of capA gene encoding cold shock protein were found in genome of Z1-20 ^T that may help Z1-20 ^T in cold-adaptation. Strain Z1-20 ^T comprised lysine as the diagnostic diamino acid. Based on the results of phylogenetic, phenotypic and chemotaxonomic features, strain Z1-20 ^T represents a novel species of a novel taxon of genus Arthrobacter, for which the name Arthrobacter terrae gen. nov., sp. nov. is proposed.

Isolation and characterization of fast-growing green snow bacteria from coastal East Antarctica

Snow microorganisms play a significant role in climate change and affecting the snow melting rate in the Arctic and Antarctic regions. While research on algae inhabiting green and red snow has been performed extensively, bacteria dwelling in this biotope have been studied to a much lesser extent. In this study, we performed 16S rRNA gene amplicon sequencing of two green snow samples collected from the coastal area of the eastern part of Antarctica and conducted genotypic and phenotypic profiling of 45 fast-growing bacteria isolated from these samples. 16S rRNA gene amplicon sequencing of two green snow samples showed that bacteria inhabiting these samples are mostly represented by families Burkholderiaceae (46.31%), Flavobacteriaceae (22.98%), and Pseudomonadaceae (17.66%). Identification of 45 fast-growing bacteria isolated from green snow was performed using 16S rRNA gene sequencing. We demonstrated that they belong to the phyla Actinobacteria and Proteobacteria, and are represented by the genera Arthrobacter, Cryobacterium, Leifsonia, Salinibacterium, Paeniglutamicibacter, Rhodococcus, Polaromonas, Pseudomonas, and Psychrobacter. Nearly all bacterial isolates exhibited various growth temperatures from 4°C to 25°C, and some isolates were characterized by a high level of enzymatic activity. Phenotyping using Fourier transform infrared (FTIR) spectroscopy revealed a possible accumulation of intracellular polymer polyhydroxyalkanoates (PHA) or lipids in some isolates. The bacteria showed different lipids/PHA and protein profiles. It was shown that lipid/PHA and protein spectral regions are the most discriminative for differentiating the isolates.

Pseudarthrobacter psychrotolerans sp. nov., a cold-adapted bacterium isolated from Antarctic soil

A novel cold-tolerant bacterium, designated strain YJ56T, was isolated from Antarctic soil collected from the Cape Burk area. Phylogenetic analysis through 16S rRNA gene sequence similarity revealed that strain YJ56T was most closely related to the genus Pseudarthrobacter , including Pseudarthrobacter oxydans DSM 20119T (99.06 % similarity), Pseudarthrobacter polychromogenes DSM 20136T (98.98 %) and Pseudarthrobacter sulfonivorans ALLT (98.76 %). The genome size (5.2 Mbp) of strain YJ56T was the largest among all the published genomes of Pseudarthrobacter type strains (4.2–5.0 Mbp). The genomic G+C content of strain YJ56T (64.7 mol%) was found to be consistent with those of other Pseudarthrobacter strains (62.0–71.0 mol%). The average nucleotide identity and average amino acid identity values between strain YJ56T and P. sulfonivorans ALLT were estimated at 84.1 and 84.2 %, respectively. The digital DNA–DNA hybridization value between the two strains was calculated to be 28.0 %. This rod-shaped and obligate aerobic strain exhibited no swimming or swarming motility. It had catalase activity but no oxidase activity. Cells grew at 4–28 °C (optimum, 13 °C) and pH 5.0–11.0 (optimum, pH 7.0) and with 0–6.0 % (w/v) NaCl (optimum, 0%) in Reasoner's 2A medium. MK-9 (H2) was the sole menaquinone. Two-dimensional TLC results revealed that the primary polar lipids were diphosphatidylglycerol, phosphatidylglycerol, two glycolipids and phosphatidylinositol. Fatty acid methyl ester analysis showed that anteiso-C15 : 0, anteiso-C17 : 0, iso-C15 : 0, C16 : 0 and iso-C16 : 0 were the major cellular fatty acids in strain YJ56T. Based on phenotypic and genotypic characteristics, strain YJ56T represents a novel species of the genus Pseudarthrobacter , and thus the name Pseudarthrobacter psychrotolerans sp. nov is proposed. The type strain is YJ56T (=JCM 33881T=KACC 21510T).

Arthrobacter sulfonylureivorans sp. nov., isolated from a sulfonylurea herbicides degrading consortium enriched with birch forest soil

A gram-stain positive, aerobic, motile, rod-shaped bacterium, designated strain LAM7117^T, was isolated from a sulfonylurea herbicides degrading consortium enriched with birch forest soil. The optimal temperature and pH for the growth of strain LAM7117^T were 35 °C and 7.5, respectively. Strain LAM7117^T could grow in the presence of NaCl with concentration up to 9% (w/v). Strain LAM7117^T formed a distinct phylogenetic subclade within the genus Arthrobacter in the phylogenetic trees built with 16S rRNA gene sequences and shared the highest similarity with A. crystallopoietes JCM 2522^T (97.7%). The values of digital DNA-DNA relatedness and Avery Nucleotide Identity based on the genome sequences between LAM7117^T and A. crystallopoietes JCM 2522^T were 21.4 and 77.4%, respectively. The genomic DNA G + C content was 65.9 mol%. The major cellular fatty acids were anteiso-C_15:0, iso-C_16:0 and anteiso-C_17:0. The cell wall peptidoglycan contained the amino acids as glycine, lysine, alanine and glutamic acid. The major polar lipids present in strain LAM7117^T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl inositol, two unidentified glycolipids and one unidentified lipid. The predominant menaquinones of strain LAM7117^T were MK-8 and MK-9. Based on the phenotypic characteristics, chemotaxonomic data and genotypic analyses, strain LAM7117^T should be classified as a novel species of genus Arthrobacter, for which the name Arthrobacter sulfonylureivorans sp. nov. is proposed. The type strain is LAM7117^T (= JCM 32824^T = CGMCC 1.16681^T).

Taxonomically Characterized and Validated Bacterial Species Based on 16S rRNA Gene Sequences from India During the Last Decade

Microbial taxonomy dealing with identification and characterization of prokaryotes like bacteria and archaea has always been a major area of research all over the world. Exploring diversity of microbes and description of novel species with different genes and secondary compounds is of utmost importance for better future and sustenance of life. India having an enormous range of ecosystems and diverse species inhabiting these niches is considered to be one of the richest biodiversity regions of the world. During the last decade, with newer methodologies and better technology, the prokaryotic taxonomy from India has extended our inventory of microbial communities in specific niches. However, there still exist some limitations in classifying the microbes from India as compared to that is done world-over. This review enlists the taxonomic description of novel taxa of prokaryotes from India in the past decade. A total of 378 new bacterial species have been classified from different habitats in India in the last ten years and no descriptions of archaeal species is documented till date.

Chemoorganotrophic Bacteria From Lake Fryxell, Antarctica, Including Pseudomonas Strain LFY10, a Cold-Adapted, Halotolerant Bacterium Useful in Teaching Labs

Lake Fryxell, situated in the McMurdo Dry Valleys of Antarctica, is an intriguing aquatic ecosystem because of its perennial ice cover, highly stratified water column, and extreme physicochemical conditions, which collectively restrict lake biodiversity to solely microbial forms. To expand our current understanding of the cultivable biodiversity of Lake Fryxell, water samples were collected from depths of 10 and 17 m, and pure cultures of eight diverse strains of aerobic, chemoorganotrophic bacteria were obtained. Despite having high 16S rRNA gene sequence similarity to mesophilic bacteria inhabiting various temperate environments, all Lake Fryxell isolates were psychrotolerant, with growth occurring at 0°C and optimal growth from 18–24°C for all isolates. Phylogenetic analyses showed the isolates to be members of six taxonomic groups, including the genera Brevundimonas, Arthrobacter, Sphingobium, Leifsonia, and Pseudomonas, as well as the family Microbacteriaceae (one strain could not reliably be assigned to a specific genus based on our analysis). Pseudomonas strain LFY10 stood out as a useful tool for teaching laboratory activities because of its substantial cold adaptation (visible growth is evident in 1–2 days at 4°C), beta-hemolytic activity, and halotolerance to 8.5% (w/v) NaCl. These cold-adapted bacteria likely play a role in carbon mineralization and other nutrient cycling in Lake Fryxell, and their characterization broadens our understanding of microbial biodiversity in aquatic polar ecosystems.

The Fecal Metagenomics of Malayan Pangolins Identifies an Extensive Adaptation to Myrmecophagy

The characteristics of flora in the intestine of an animal, including the number and abundance of different microbial species and their functions, are closely related to the diets of the animal and affect the physical condition of the host. The Malayan pangolin (Manis javanica) is an endangered species that specializes in myrmecophagy. Analyzing the microbiome in the intestine of the pangolin is imperative to protect this species. By sequencing the metagenomes of the feces of four pangolins, we constructed a non-redundant catalog of 211,868 genes representing 1,811 metagenomic species. Taxonomic annotation revealed that Bacteroidetes (49.9%), Proteobacteria (32.2%), and Firmicutes (12.6%) are the three main phyla. The annotation of gene functions identified 5,044 genes from 88 different glycoside hydrolase (GH) families in the Carbohydrate-Active enZYmes database and 114 gene modules related to chitin-degrading enzymes, corresponding to the catalytic domains of GH18 family enzymes, containing chitinase genes of classes III and V in the dataset. Fourteen gene modules corresponded to the catalytic domains of GH19 family enzymes, containing chitinase genes of classes I, II, and IV. These genes were found in 37 species belonging to four phyla: Bacteroidetes, Cyanobacteria, Firmicutes, and Proteobacteria. Moreover, when the metabolic pathways of these genes were summarized, 41,711 genes were associated with 147 unique KEGG metabolic pathways, and these genes were assigned to two Gene Ontology terms: metabolic process and catalytic activity. We also found several species that likely play roles in the digestion of cellulose and may be able to degrade chitin, including Enterobacter cloacae, Lactococcus lactis, Chitinimonas koreensis, and Chitinophaga pinensis. In addition, we identified some intestinal microflora and genes related to diseases in pangolins. Twenty-seven species were identified by STAMP analysis as differentially abundant in healthy and diseased animals: 20 species, including Cellulosilyticum lentocellum and Lactobacillus reuteri, were more abundant in healthy pangolins, while seven species, including Odoribacter splanchnicus, Marinilabilia salmonicolor, Xanthomonas citri, Xanthomonas vasicola, Oxalobacter formigenes, Prolixibacter bellariivorans, and Clostridium bolteae, were more abundant in diseased pangolins. These results will support the efforts to conserve pangolins.

Molecular Analysis of Arthrobacter Myovirus vB_ArtM-ArV1: We Blame It on the Tail

This is the first report on a myophage that infects Arthrobacter A novel virus, vB_ArtM-ArV1 (ArV1), was isolated from soil using Arthrobacter sp. strain 68b for phage propagation. Transmission electron microscopy showed its resemblance to members of the family Myoviridae: ArV1 has an isometric head (∼74 nm in diameter) and a contractile, nonflexible tail (∼192 nm). Phylogenetic and comparative sequence analyses, however, revealed that ArV1 has more genes in common with phages from the family Siphoviridae than it does with any myovirus characterized to date. The genome of ArV1 is a linear, circularly permuted, double-stranded DNA molecule (71,200 bp) with a GC content of 61.6%. The genome includes 101 open reading frames (ORFs) yet contains no tRNA genes. More than 50% of ArV1 genes encode unique proteins that either have no reliable identity to database entries or have homologues only in Arthrobacter phages, both sipho- and myoviruses. Using bioinformatics approaches, 13 ArV1 structural genes were identified, including those coding for head, tail, tail fiber, and baseplate proteins. A further 6 ArV1 ORFs were annotated as encoding putative structural proteins based on the results of proteomic analysis. Phylogenetic analysis based on the alignment of four conserved virion proteins revealed that Arthrobacter myophages form a discrete clade that seems to occupy a position somewhat intermediate between myo- and siphoviruses. Thus, the data presented here will help to advance our understanding of genetic diversity and evolution of phages that constitute the order CaudoviralesIMPORTANCE Bacteriophages, which likely originated in the early Precambrian Era, represent the most numerous population on the planet. Approximately 95% of known phages are tailed viruses that comprise three families: Podoviridae (with short tails), Siphoviridae (with long noncontractile tails), and Myoviridae (with contractile tails). Based on the current hypothesis, myophages, which may have evolved from siphophages, are thought to have first emerged among Gram-negative bacteria, whereas they emerged only later among Gram-positive bacteria. The results of the molecular characterization of myophage vB_ArtM-ArV1 presented here conform to the aforementioned hypothesis, since, at a glance, bacteriophage vB_ArtM-ArV1 appears to be a siphovirus that possesses a seemingly functional contractile tail. Our work demonstrates that such "chimeric" myophages are of cosmopolitan nature and are likely characteristic of the ecologically important soil bacterial genus Arthrobacter.

Genome Sequence of Arthrobacter antarcticus Strain W2, Isolated from a Slaughterhouse

We report the draft genome sequence of Arthrobacter antarcticus strain W2, which was isolated from a wall of a small slaughterhouse in Denmark. The 4.43-Mb genome sequence was assembled into 170 contigs.

Review of the taxonomy of the genus Arthrobacter, emendation of the genus Arthrobacter sensu lato, proposal to reclassify selected species of the genus Arthrobacter in the novel genera Glutamicibacter gen. nov., Paeniglutamicibacter gen. nov., Pseudoglutamicibacter gen. nov., Paenarthrobacter gen. nov. and Pseudarthrobacter gen. nov., and emended description of Arthrobacter roseus

In this paper, the taxonomy of the genus Arthrobacter is discussed, from its first description in 1947 to the present state. Emphasis is given to intrageneric phylogeny and chemotaxonomic characteristics, concentrating on quinone systems, peptidoglycan compositions and polar lipid profiles. Internal groups within the genus Arthrobacter indicated from homogeneous chemotaxonomic traits and corresponding to phylogenetic grouping and/or high 16S rRNA gene sequence similarities are highlighted. Furthermore, polar lipid profiles and quinone systems of selected species are shown, filling some gaps concerning these chemotaxonomic traits. Based on phylogenetic groupings, 16S rRNA gene sequence similarities and homogeneity in peptidoglycan types, quinone systems and polar lipid profiles, a description of the genus Arthrobacter sensu lato and an emended description of Arthrobacter roseus are provided. Furthermore, reclassifications of selected species of the genus Arthrobacter into novel genera are proposed, namely Glutamicibacter gen. nov. (nine species), Paeniglutamicibacter gen. nov. (six species), Pseudoglutamicibacter gen. nov. (two species), Paenarthrobacter gen. nov. (six species) and Pseudarthrobacter gen. nov. (ten species).

Arthrobacter nanjingensis sp. nov., a mineral-weathering bacterium isolated from forest soil

A Gram-stain-positive, non-motile, rod- or coccoid-shaped actinobacterium, designated strain A33T, was isolated from a forest soil sample from Nanjing, Jiangsu Province, PR China. The strain grew optimally at 30 °C, pH 7.0 and with 3 % NaCl (w/v). Phylogenetic analysis of the strain, based on 16S rRNA gene sequences, showed that it was most closely related to Arthrobacter woluwensis (98.4 % sequence similarity), Arthrobacter humicola (97.5 %), Arthrobacter globiformis (97.4 %), Arthrobacter oryzae (97.3 %) and Arthrobacter cupressi (97.0 %). The major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C15 : 0; MK-9(H2) was the predominant respiratory quinone. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and three glycolipids. Cell-wall analysis revealed that the peptidoglycan type was A3α, based on l-lysine-l-alanine; the cell-wall sugars were galactose and mannose. The genomic G+C content of strain A33T was 66.8 mol%. The low DNA–DNA relatedness values between strain A33T and recognized species of the genus Arthrobacter and many phenotypic properties supported the classification of strain A33T as a representative of a novel species of the genus Arthrobacter , for which the name Arthrobacter nanjingensis sp. nov. is proposed. The type strain is A33T ( = CCTCC AB 2014069T = DSM 28237T).

Isolation and characterization of vB_ArS-ArV2 - first Arthrobacter sp. infecting bacteriophage with completely sequenced genome

This is the first report on a complete genome sequence and biological characterization of the phage that infects Arthrobacter. A novel virus vB_ArS-ArV2 (ArV2) was isolated from soil using Arthrobacter sp. 68b strain for phage propagation. Based on transmission electron microscopy, ArV2 belongs to the family Siphoviridae and has an isometric head (∼63 nm in diameter) with a non-contractile flexible tail (∼194×10 nm) and six short tail fibers. ArV2 possesses a linear, double-stranded DNA genome (37,372 bp) with a G+C content of 62.73%. The genome contains 68 ORFs yet encodes no tRNA genes. A total of 28 ArV2 ORFs have no known functions and lack any reliable database matches. Proteomic analysis led to the experimental identification of 14 virion proteins, including 9 that were predicted by bioinformatics approaches. Comparative phylogenetic analysis, based on the amino acid sequence alignment of conserved proteins, set ArV2 apart from other siphoviruses. The data presented here will help to advance our understanding of Arthrobacter phage population and will extend our knowledge about the interaction between this particular host and its phages.

Draft Genome Sequence of Arthrobacter crystallopoietes Strain BAB-32, Revealing Genes for Bioremediation

Arthrobacter crystallopoietes strain BAB-32, a Gram-positive obligate aerobic actinobacterium having potential application in bioremediation and bioreduction of a few metals, was isolated from rhizosphere soil of Gandhinagar, Gujarat, India. The draft genome (4.3 Mb) of the strain revealed a few vital gene clusters involved in the metabolism of aromatic compounds, zinc, and sulfur.

Arthrobacter cryoconiti sp. nov., a psychrophilic bacterium isolated from alpine glacier cryoconite

A Gram-stain-positive, aerobic, non-motile, psychrophilic bacterium, designated strain Cr6-08(T), was isolated from alpine glacier cryoconite. Growth of strain Cr6-08(T) occurred at 1-25 °C. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain Cr6-08(T) is most closely related to members of the genus Arthrobacter. Strain Cr6-08(T) possessed chemotaxonomic properties consistent with those of the genus Arthrobacter, such as peptidoglycan type A3α (l-Lys-L-Ala(4)), MK-9(H(2)) as major menaquinone and anteiso- and iso-branched compounds (anteiso-C(15 : 0) and iso-C(15 : 0)) as major cellular fatty acids. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, one unknown glycolipid and three unknown polar lipids. The genomic DNA G+C content of strain Cr6-08(T) was 57.3 mol%. On the basis of phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA-DNA relatedness data, strain Cr6-08(T) is considered to represent a novel species of the genus Arthrobacter, for which the name Arthrobacter cryoconiti sp. nov. is proposed. The type strain is Cr6-08(T) ( = DSM 23324(T)  = LMG 26052(T)  = CGMCC 1.10698(T)).