Family Microbacteriaceae Research Articles

Microcella flavibacter sp. nov., isolated from marine sediment, and reclassification of Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila as Microcella frigidaquae comb.nov., Microcella indica nom. nov., and Microcella alkalica nom. nov.

A novel Gram-staining positive, aerobic, rod-shaped, non-motile and yellow-pigmented actinobacterium, designated strain WY83T, was isolated from a marine sediment of Indian Ocean. Strain WY83T grew optimally at 30-35°C, pH 7-8 and with 0-3% (w/v) NaCl. The predominant menaquinones were MK-10, MK-11 and MK-12, and the major fatty acids were C19:1 ω9c/C19:1 ω11c, anteiso-C15:0, C17:0 3OH, and iso-C16:0. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid. The cell-wall peptidoglycan contained lysine as a diamino acid. The DNA G + C content was 72.3mol%. Phylogenetic analysis based on 16S rRNA gene sequences and ninety-two bacterial core genes indicated that strain WY83T formed an evolutionary lineage with Chryseoglobus frigidaquae JCM 14730T, Chryseoglobus indicus CTD02-10-2T, Yonghaparkia alkaliphila JCM 15138T, Microcellaalkaliphila DSM 18851T andMicrocella putealisDSM 19627T within the radiation enclosing members of the family Microbacteriaceae. All pairwise percentage of conserved proteins between strain WY83T and the closely related phylogenetic neighbors were greater than 65%. The average nucleotide identity and in silico DNA-DNA hybridization values were both below the thresholds used for the delineation of a new species. On the basis of the evidence presented, strains WY83T, Y. alkaliphilaJCM 15138T, C. frigidaquaeJCM 14730T, M.alkaliphilaDSM 18851TandM. putealisDSM 19627T should belong to different species of the same genus. Strain WY83T represents a novel species of the genus Microcella, for which the name Microcella flavibacter sp. nov. is proposed. The type strain is WY83T (= KCTC 39637T = MCCC 1A07099T). Furthermore, Chryseoglobus frigidaquae, Chryseoglobus indicus, and Yonghaparkia alkaliphila were reclassified as Microcella frigidaquae comb.nov., Microcella indica nom.nov., and Microcella alkalica nom.nov., respectively.

Cell wall galactofuranan and pyruvate-containing galactomannan in the cell walls of Clavibacter strains

The cell wall glycopolymer structures of plant-associated strains Clavibacter sp. VKM Ac-1371, Clavibacter sp. VKM Ac-1372 and Clavibacter sp. VKM Ac-1374, members of three putative new species (family Microbacteriaceae, class Actinobacteria) were studied. Each strain was found to contain two glycopolymers, neutral and acidic ones. The main chain of neutral polymer, identical in all three strains, is (1 → 6)-linked β-d-galactofuranan with every second galactofuranose residue substituted at position 2 by side disaccharide, α-d-Manp-(1 → 2)-α-d-Ribf-(1 → . The second, acidic polymer, is pyruvate-containing galactomannan with the repeating unit, →3)-α-d-Galp-(1 → 3)-α-d-[4,6-S-Pyr]-Manp-(1 → 3)-α-d-Manp-(1 → . Reducing mannopyranose residues of the acidic polysaccharides repeating unit from strains VKM Ac-1372 and VKM Ac-1374 bear O-acetyl residues additionally. The cell wall glycopolymer structures were established by chemical and NMR spectroscopic methods with using one- and two-dimensional techniques 1H,1H COSY, TOCSY, ROESY and 1H,13C HSQC, HMBC. The results obtained provide new data on diversity of the bacterial cell wall glycopolymers and may prove valuable for microbial taxonomy and insight into the molecular mechanisms of interactions between bacteria and plants and also of bacterial adaptation to survival in desert systems.

Marinisubtilis pacificus gen. nov., sp. nov., a Member of the Family Microbacteriaceae Isolated From a Deep-Sea Seamount.

A Gram-stain-positive, yellow, aerobic, slender rod-shaped bacterial strain, designated KN1116T, was isolated from a deep-sea seamount. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain KN1116T was related to the genus Chryseoglobus and had highest 16S rRNA gene sequence identity with Chryseoglobus frigidaquae CW1T (98.5%). The predominant cellular fatty acids were anteiso-C15:0 and iso-C16:0. The quinone system for strain KN1116T comprised menaquinone MK-12, MK-11, MK-10 and MK-13. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, six unknown glycolipids, two unidentified phospholipids and one unknown polar lipid. The cell-wall peptidoglycan of strain KN1116T was of the type B1β, containing 2,4-diaminobutyric acid as the diamino acid. Genome sequencing revealed the strain KN1116T has a genome size of 2.7 Mbp and a G+C content of 69.4mol%. Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strain KN1116T represents a novel species of a novel genus of the family Microbacteriaceae, for which the name Marinisubtilis pacificus gen. nov., sp. nov. is proposed. The type strain of Marinisubtilis pacificus is KN1116T (=CGMCC 1.17143T =KCTC 49299T).

D-Rhamnan and Pyruvate-Containing Teichuronic Acid from the Cell Wall of Rathayibacter sp. VKM Ac-2759.

Rathayibacter sp. VKM Ac-2759 (family Microbacteriaceae, class Actinobacteria) contains two glycopolymers in the cell wall. The main chain of rhamnan, glycopolymer 1, is built from the repeating tetrasaccharide units carrying terminal arabinofuranose residues at the non-reducing end, →3)-α-[α-D-Araf-(1→2)]-D-Rhap-(1→2)-α-D-Rhap-(1→3)-α-D-Rhap-(1→2)-α-D-Rhap-(1→. Similar to other described Rathayibacter species, rhamnose in the neutral glycopolymer of the VKM Ac-2759 strain is present in the D-configuration. Acetalated with pyruvic acid teichuronic acid, glycopolymer 2, is composed of the repeating tetrasaccharide units, →4)-β-D-GlcpA-(1→4)-β-D-Galp-(1→4)-β-D-Glcp-(1→3)-β-[4,6-S-Pyr]-D-Manp-(1→. Glycopolymers 1 and 2 were identified in prokaryotic microorganisms for the first time and their structures were established by chemical analysis and NMR spectroscopy. The obtained data can be used in taxonomic research, as well as for elucidating the mechanisms of plant colonization and infection by bacteria of the Rathayibacter genus.

Genome Sequence of a Novel Soil Actinomycete, Protaetiibacter sp. Strain SSC-01.

The family Microbacteriaceae represents a diverse and important group of soil bacteria in the phylum Actinobacteria Here, we report the genome sequence of a soil Microbacteriaceae strain, Protaetiibacter sp. strain SSC-01, the second putative species of the genus. Iron acquisition and xylose metabolism are central pathways identified in the annotated genome.

Novel galactofuranan and pyruvylated galactomannan in the cell wall of Clavibacter michiganensis subsp. michiganensis VKM Ac-1403T

The cell wall of Clavibacter michiganensis subsp. michiganensis VKM Ас-1403Т (family Microbacteriaceae, class Actinobacteria) contains two polysaccharides. The first one is neutral (1 → 6) linked galactofuranan in which every second galactofuranose residue in the main chain substituted at position 3 by side trisaccharide, β-D-GlcpNAc-(1 → 3)-α-L-Rhap-(1 → 2)-α-D-Fucp-(1 →. The second polymer is pyruvylated galactomannan with the repeating unit, →3)-α-D-Galp-(1 → 3)-α-D-[4,6-S-Pyr]-Manp-(1 → 3)-α-D-Manp-(1 →. The cell wall glycopolymer structures were established by chemical and NMR spectroscopic methods. The obtained results provide new data on the cell wall composition of plant pathogenic species of the genus Clavibacter and can promote understanding the molecular mechanisms involved in colonization and infection of plants.

D-rhamnan and teichuronic acid from the cell wall of Rathayibacter caricis VKM Ac-1799T

The cell wall of Rathayibacter caricis VKM Ac-1799T (family Microbacteriaceae, class Actinobacteria) was found to contain both neutral and acidic glycopolymers. The first one is D-rhamnopyranan with main chain →2)-α-D-Rhap-(1 → 3)-α-D-Rhap-(1→, where a part of 2-substituted residues bears as a side-chain at position 3 α-D-Manp residues or disaccharides α-D-Araf-(1→2)-α-D-Manp-(1 → . The second polymer is a teichuronic acid with a branched repeating units composed of seven monosaccharides →4)-α-[β-D-Manp-(1 → 3)]-D-Glcp-(1 → 4)-β-D-GlcpA-(1 → 2)-β-[4,6Pyr]-D-Manp-(1 → 4)-β-L-Rhap-(1 → 4)-β-D-Glcp-(1 → 4)-β-D-Glcp-(1 → . The structures of the polymers were determined by chemical and NMR spectroscopic methods.

Draft Genome Sequences of 13 Plant-Associated Actinobacteria of the Family Microbacteriaceae.

Draft genome sequences of 13 bacterial strains from the family Microbacteriaceae were generated using Illumina technology. The genome sizes varied from 3.0 to 4.8 Mb, and the DNA G+C content was 68.1 to 72.5%. The sequences obtained will contribute to the development of genome-based taxonomy and understanding of molecular interactions between bacteria and plants.

Genomic Insights of Cryobacterium Isolated From Ice Core Reveal Genome Dynamics for Adaptation in Glacier.

Glacier is the dominant cold habitat in terrestrial environments, providing a model ecosystem to explore extremophilic strategies and study early lives on Earth. The dominant form of life in glaciers is bacteria. However, little is known about past evolutionary processes that bacteria underwent during adaptation to the cryosphere and the connection of their genomic traits to environmental stressors. Aiming to test the hypothesis that bacterial genomic content and dynamics are driven by glacial environmental stressors, we compared genomes of 21 psychrophilic Cryobacterium strains, including 14 that we isolated from three Tibetan ice cores, to their mesophilic counterparts from the same family Microbacteriaceae of Actinobacteria. The results show that psychrophilic Cryobacterium underwent more dynamic changes in genome content, and their genomes have a significantly higher number of genes involved in stress response, motility, and chemotaxis than their mesophilic counterparts (P < 0.05). The phylogenetic birth-and-death model imposed on the phylogenomic tree indicates a vast surge in recent common ancestor of psychrophilic Cryobacterium (gained the greatest number of genes by 1,168) after the division of the mesophilic strain Cryobacterium mesophilum. The expansion in genome content brought in key genes primarily of the categories “cofactors, vitamins, prosthetic groups, pigments,” “monosaccharides metabolism,” and “membrane transport.” The amino acid substitution rates of psychrophilic Cryobacterium strains are two orders of magnitude lower than those in mesophilic strains. However, no significantly higher number of cold shock genes was found in psychrophilic Cryobacterium strains, indicating that multi-copy is not a key factor for cold adaptation in the family Microbacteriaceae, although cold shock genes are indispensable for psychrophiles. Extensive gene acquisition and low amino acid substitution rate might be the strategies of psychrophilic Cryobacterium to resist low temperature, oligotrophy, and high UV radiation on glaciers. The exploration of genome evolution and survival strategies of psychrophilic Cryobacterium deepens our understanding of bacterial cold adaptation.

Rhamnomannans and Teichuronic Acid from the Cell Wall of Rathayibacter tritici VKM Ac-1603T.

The structures of three cell wall glycopolymers of the phytopathogen Rathayibacter tritici VKM Ac-1603T (family Microbacteriaceae, order Micrococcales, class Actinobacteria) were established by chemical methods and NMR spectroscopy. Polymer 1 is a branched rhamnomannan with the repeating unit →3)-α-[β-D-Xylp-(1→2)]-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→; polymer 2 is a linear rhamnomannan with the repeating unit →2)-α-D-Manp-(1→2)-α-D-Rhap-(1→3)-α-D-Manp-(1→2)-α-D-Rhap-(1→; polymer 3 is a branched teichuronic acid containing monosaccharide residues GlcA, Gal, Man, and Glc at a 1 : 1 : 1 : 5 ratio (see the text for the structures). It has been demonstrated that representatives of four Rathayibacter species studied to date (R. tritici VKM Ac-1603T, R. iranicus VKM Ac-1602 T, R. toxicus VKM Ac-1600 and "Rathayibacter tanaceti" VKM Ac-2596) contain differing patterns of phosphate-free glycopolymers. At the same time, the above Rathayibacter strains have a common property - the presence of rhamnomannans with D-rhamnose. These rhamnomannans may be linear or branched and differing in the positions of glycosidic bonds and side substituents. The presence in the cell wall of rhamnomannans with D-rhamnose may serve as useful chemotaxonomic marker of the genus Rathayibacter.

Bacterial wilt of dry beans caused by Curtobacterium flaccumfaciens pv. flaccumfaciens: A new threat from an old enemy.

Bacterial wilt and tan spot of dry beans (family Fabaceae), caused by Curtobacterium flaccumfaciens pv. flaccumfaciens, is an important emerging disease threatening the edible legume industry around the globe. The management of bacterial wilt has been a major problem since its original description in 1922. This is in part due to the seedborne nature of the pathogen allowing the bacterium to be transmitted long distances via infected seeds, as well as a lack of detailed molecular information concerning the pathogenicity repertoires and virulence determinates of the pathogen. Identification can also be difficult owing to the presence of five different colony colour variants (i.e., yellow, orange, pink, purple, and red) on culture media. In this review, we provide an overview of the aetiology, epidemiology, and management strategies of bacterial wilt disease. First, a comprehensive and comparative symptomology of the disease on different dry bean species is described. Then, the taxonomic history of the causal agent and utility of high‐throughput sequencing‐based approaches in the precise characterization of the pathogen is explained. Furthermore, we provide an updated outline on the global distribution of the pathogen, highlighting expansion of the causal agent into the areas with no history of the disease until the beginning of the current century. Finally, because there are limited options for use of conventional pesticides against the pathogen, we highlight the use of integrated pest management strategies, for example quarantine inspections, resistant cultivars, and crop sanitation, to combat the risk of bacterial wilt disease in the dry bean industry.Disease symptomsInterveinal chlorosis on leaflets leading to necrotic areas and systemic wilt. Seed discolouration to yellow, orange, pink, or purple is seen in white‐seeded cultivars.Host rangeCauses bacterial wilt and tan spot disease on edible dry beans in the Fabaceae family, including common bean (Phaseolus vulgaris), cowpea (Vigna unguiculata), mungbean (Vigna radiata), soybean (Glycine max), as well as a number of weed species.Taxonomic status of the pathogenBacteria; phylum Actinobacteria; order Actinomycetales; suborder: Micrococcineae; family Microbacteriaceae; genus Curtobacterium; species Curtobacterium flaccumfaciens. Synonyms Corynebacterium flaccumfaciens subsp. flaccumfaciens; Corynebacterium flaccumfaciens pv. flaccumfaciens, Corynebacterium flaccumfaciens, Phytomonas flaccumfaciens, Bacterium flaccumfaciens. Microbiological propertiesMulticoloured (yellow, orange, pink, purple, and red), gram‐positive, aerobic, curved rod, nonspore‐forming, polar flagellated, motile cells.DistributionWidespread in America (Brazil, Canada, and the USA), Australia, and Iran. Restricted occurrence in Africa and Europe.Phytosanitary categorizationEPPO A2 list no. 48, EU Annex II⁄B.

Lysinimonas yzui sp. nov., isolated from cattail root soil from mine tailings.

A yellow-pigmented, Gram-stain-negative, aerobic, non-motile rod shaped, mesophilic bacterium, designated strain N7XX-4T, was isolated from cattail root grown on the mine tailings of Phoenix mountain, Tongling city, Anhui Province (PR China). Analysis of the 16S rRNA gene sequence revealed that the strain represented a novel member of the family Microbacteriaceae. The nearest phylogenetic neighbour was Lysinimonas kribbensis MSL-13T (97.8 % 16S rRNA gene sequence similarity). The most abundant fatty acid in whole cells of N7XX-4T was anteiso-C15 : 0 (29.9 %). The predominant menaquinones were MK-12(H2), MK-13(H2) and MK-11(H2). The peptidoglycan type of the isolate was B1δ with l-Lys as the diagnostic cell-wall diamino acid. On the basis of differences in phenotypic and genotypic characteristics, strain N7XX-4T (=CGMCC 1.16548T=DSM 106791T=JCM 32630T) is designated as the type strain of a novel species of the genus Lysinimonas, for which the name Lysinimonas yzui sp. nov. is proposed.

Do combined nanoscale polystyrene and tetracycline impact on the incidence of resistance genes and microbial community disturbance in Enchytraeus crypticus?

It has been proved that nanoplastics can effectively adsorb pollutants and thus influence their behavior and availability. The combined toxic effects of nanoplastic and its adsorbed pollutant on the soil fauna are still not well known. We used high-throughput quantitative PCR to explore the effects of oral nanoscale polystyrene and tetracycline exposure on antibiotic resistance genes in the soil invertebrate Enchytraeus crypticus, and used bacterial 16S rRNA gene amplification sequencing to examine the response of the microbiome of E. crypticus. After 14 days of tetracycline and nanoscale polystyrene exposure, we terminated exposure and monitored the restoration of ARGs and microbiome in the E. crypticus. Results showed that the number of ARGs, especially macrolide-lincosamide-streptogramin B (MLSB), tetracycline ARGs, as well as multidrug ARGs, increased with exposure to nanoscale polystyrene and tetracycline. The abundance of Aminoglycoside and Beta_Lactamase ARGs in E. crypticus also significantly increased. The exposure significantly perturbed the abundance of families Microbacteriaceae, Streptococcaceae, Enterobacteriaceae, Rhodocyclaceae and Sphinomonadaceae. After terminating exposure for 14 days, the diversity and abundance of ARGs were not completely restored, while the microbiome was not permanently changed but reversibly impacted.

Rhodoluna limnophila sp. nov., a bacterium with 1.4 Mbp genome size isolated from freshwater habitats located in Salzburg, Austria.

Three actinobacterial strains, 27D-LEPIT, 1B-Mac and 36A-HELLB, were isolated from small standing and running freshwater habitats located in Salzburg, Austria. Phylogenetic reconstructions based on 16S rRNA gene sequences and genome based on concatenated amino acid sequences of 119 single-copy genes referred the three strains within the family Microbacteriaceae to the genus Rhodoluna. The strains showed 100 % 16S rRNA gene sequence similarities to the previously described Candidatus Rhodoluna limnophila. Cells were very small, approximately 0.5×0.3 µm, and showed a red pigmentation in liquid nutrient broth-soyotone-yeast extract medium as well as on agar plates. The strains assimilated a broad variety of substrates; however, the patterns differed a great deal between the three investigated strains. For strain 27D-LEPIT, the major fatty acids were iso-C14 : 0 and anteiso-C15 : 0; the identified polar lipids were phosphatidylglycerol and diphosphatidylglycerol; the major respiratory quinone was MK-11; and analysis of the peptidoglycan structure indicated the presence of type B2β (typeB10). The genomic DNA of the three strains was very small (1.4 Mbp) and had a DNA G+C content of 54 mol%. The investigated traits suggested that strains 36A-HELLB (=DSM 107805=JCM 32927), 1B-Mac (=DSM 107802=JCM 32925) and 27D-LEPIT (=JCM 32926T =DSM 107804T) represent a new species for which the name Rhodolunalimnophila sp. nov. is proposed, with strain 27D-LEPIT as the type strain.

Distinct Coastal Microbiome Populations Associated With Autochthonous- and Allochthonous-Like Dissolved Organic Matter.

Coastal zones are important transitional areas between the land and sea, where both terrestrial and phytoplankton supplied dissolved organic matter (DOM) are respired or transformed. As climate change is expected to increase river discharge and water temperatures, DOM from both allochthonous and autochthonous sources is projected to increase. As these transformations are largely regulated by bacteria, we analyzed microbial community structure data in relation to a 6-month long time-series dataset of DOM characteristics from Roskilde Fjord and adjacent streams, Denmark. The results showed that the microbial community composition in the outer estuary (closer to the sea) was largely associated with salinity and nutrients, while the inner estuary formed two clusters linked to either nutrients plus allochthonous DOM or autochthonous DOM characteristics. In contrast, the microbial community composition in the streams was found to be mainly associated with allochthonous DOM characteristics. A general pattern across the land-to-sea interface was that Betaproteobacteria were strongly associated with humic-like DOM [operational taxonomic units (OTUs) belonging to family Comamonadaceae], while distinct populations were instead associated with nutrients or abiotic variables such as temperature (Cyanobacteria genus Synechococcus) and salinity (Actinobacteria family Microbacteriaceae). Furthermore, there was a stark shift in the relative abundance of OTUs between stream and marine stations. This indicates that as DOM travels through the land-to-sea interface, different bacterial guilds continuously degrade it.

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

A novel Gram-stain-positive bacterial strain, CHu50b-6-2T, 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-6-2T 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 29148T, Frigoribacterium faeni KACC 20509T and Lysinibacter cavernae DSM 27960T, respectively. The phylogenetic trees revealed that strain CHu50b-6-2T 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-C15:0, iso-C16:0, and anteiso-C17:0 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-6-2T 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-6-2T (= KCTC 49081T = JCM 32673T).

New glycopolymers containing both D- and L-rhamnopyranoses from Rathayibacter iranicus VKM Ac-1602T cell wall

The cell wall of Rathayibacter iranicus VKM Ac-1602T (family Microbacteriaceae, class Actinobacteria) is characterised by the absence of phosphate-containing and by the presence of two rhamnose-containing glycopolymers. The first is a branched rhamnomannan, in which 60% of mannose residues of the main chain are glycosylated by terminal mannose residues: →2)-α-D-Rhap-(1 → 3)-α-[α-D-Manp-(1 → 6)]-D-Manp-(1 → . The second is a branched teichuronic acid, in which all the rhamnose residues of the main chain are glycosylated by glucose residues:→3)-α-[α-D-Glcp-(1 → 2)]-L-Rhap-(1 → 4)-β-D-GlcpA-(1 → 2)-α-D-Manp-(1 → 3)-α-D-Galp-(1 → 3)-β-D-Glcp-(1 → . Both glycopolymers have the unique structures and described in the cell walls of Gram-positive bacteria for the first time. The obtained data allow for a more complete characterisation of the cell wall of the microorganism under investigation and can serve as a phenotypic characterisation of this bacterium. The glycopolymer structures were established using chemical and nuclear magnetic resonance (NMR) spectroscopy methods.

Glaciihabitans arcticus sp. nov., a psychrotolerant bacterium isolated from Arctic soil.

A non-motile, Gram-stain-positive, rod-shaped bacterium, designated RP-3-7T, was isolated from soil sampled at the Arctic region in Cambridge Bay, NU, Canada. Cells were strictly aerobic, non-spore-forming, catalase-positive and oxidase-positive. Colonies on Reasoner's 2A agar plates were pale yellow-coloured. Strain RP-3-7T was psychrotolerant and grew optimally at 15-20 °C. Strain RP-3-7T assimilated d-glucose, d-mannitol, l-arabinose and l-proline; tolerated only 0.5 % NaCl (w/v). Phylogenetic analysis based on its 16S rRNA gene sequence revealed that strain RP-3-7T formed a lineage within the family Microbacteriaceae and clustered with members of the genus Glaciihabitans. The closest member was Glaciihabitans tibetensis MP203T (98.26 % sequence similarity). The major respiratory quinone was MK-10. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol and an unidentified glycolipid. The major cellular fatty acids were anteiso-C15 : 0, iso-C16 : 0, anteiso-C17 : 0 and anteiso-C15 : 1 A. The diagnostic amino acid was 2,4-diaminobutyric acid and whole-cell sugars were xylose, rhamnose and mannose. The DNA G+C content of strain RP-3-7T was 66.9 mol%. The average nucleotide identity and in silico DNA-DNA relatedness values between strain RP-3-7T and Glaciihabitans tibetensis MP203T were 73.79 and 20.1 %, respectively. Based on the polyphasic, genomic and phylogenetic data, strain RP-3-7T represents a novel species of the genus Glaciihabitans, for which the name Glaciihabitans arcticus sp. nov. is proposed. The type strain is RP-3-7T (=KEMB 9005-731T=KACC 21151T=NBRC 113769T).

Leucobacter muris sp. nov., isolated from the nose of a laboratory mouse.

A Gram-stain-positive, rod-shaped, aerobic, non-motile, white, opaque bacterial isolate, designated 924/12T, was isolated from the nose of a laboratory mouse in Düsseldorf, Germany. The 16S rRNA gene sequence analyses indicated the phylogenetic position of the strain within the genus Leucobacter. Similarity levels over 97 % were recorded between the 16S rRNA gene sequence of strain 924/12T and the type strains of the species Leucobacter chironomi DSM 19883T (99.5 %), followed by Leucobacter celersubsp. astrifaciens CBX151T (97.6 %), Leucobacter celersubsp. celer NAL101T (97.5 %), 'Leucobacter kyeonggiensis' F3-P9 (97.5 %), Leucobacter zeae CC-MF41T (97.3 %), Leucobacter chromiiresistens JG31T (97.1 %), Leucobacter triazinivorans JW-1T (97.1 %), Leucobacter corticis 2 C-7T (97.0 %) and Leucobacter aridicolis CIP108388T (97.0 %). DNA-DNA hybridization and whole genomic comparison, mandatory to taxonomically separate strain 924/12T from the type strain of L. chironomi, revealed similarity values of 40.4 and 30.8 %, respectively, thus below the threshold of 70 % recommended differentiating between species. The cell-wall amino acids of the novel isolate were diaminobutyric acid, alanine, glycine, threonine and glutamic acid. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, glycolipid and one unknown lipid, whereas the predominant menaquinones were MK-11 and MK-10. The genomic DNA G+C content of strain 924/12T was 70.6 mol%. Phylogenetic analyses based on the 16S rRNA gene sequences and the phenotypical differences between strain 924/12T and the other closely related type strains of the genus Leucobacter indicated that strain 924/12T represents a novel species within the genus Leucobacter, family Microbacteriaceae, for which the name Leucobacter muris sp. nov. is proposed. The type strain is 924/12T (=DSM 101948T=CCM 8761T).

Protaetiibacter intestinalis gen. nov., of the family Microbacteriaceae, isolated from gut of Protaetia brevitarsis seulensis, reclassification of Lysinimonas kribbensis Jang et al. 2013 as Pseudolysinimonas kribbensis gen. nov., comb. nov. and emended description of the genus Lysinimonas Jang et al. 2013.

A Gram-stain-positive, strictly aerobic, rod-shaped, non-spore-forming, non-motile bacterium, designated strain 2DFWR-13T, was isolated from gut of the larva of Protaetia brevitarsis seulensis, in the Republic of Korea. Strain 2DFWR-13T showed high sequence similarities to Lysinimonas kribbensis MSL-13T (97.7 %), Homoserinibacter gongjuensis 5GH26-15T (97.2 %), Microbacterium deminutum KV-483T (97.1 %) and Herbiconiux ginsengi CGMCC 4.3491T (97.1 %). The predominant fatty acids (>10 % of the total fatty acids) were anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0. The major menaquinones were MK-13 and MK-12. The peptidoglycan type was type B2 with the diagnostic amino acid d-DAB. The N-acyl type of the murein was glycolyl. The polar lipids consisted of diphosphatidylglycerol, an unidentified glycolipid and an unidentified lipid. The DNA G+C content was 71.5 mol%. Based on its phylogenetic distinctiveness and distinguishing phenotypic characteristics, we conclude that strain 2DFWR-13T represents a novel genus and species of the family Microbacteriaceae, for which the name Protaetiibacter intestinalis gen. nov., sp. nov. is proposed. The type strain of Protaetiibacter intestinalis is 2DFWR-13T (=KACC 19321T=NBRC 113050T). In addition, an emended description of the genus LysinimonasJang et al. 2013 and the reclassification of Lysinimonas kribbensisJang et al. 2013 as Pseudolysinimonas kribbensis gen. nov., comb. nov. are proposed.