Transfer of Sphingorhabdus marina, Sphingorhabdus litoris, Sphingorhabdus flavimaris and Sphingorhabdus pacifica corrig. into the novel genus Parasphingorhabdus gen. nov. and Sphingopyxis baekryungensis into the novel genus Novosphingopyxis gen. nov. within the family Sphingomonadaceae.

During a phylogenetic analysis of Sphingorhabdus and its closely related genera in the family Sphingomonadaceae, we found that the genus Sphingorhabdus and the species Sphingopyxis baekryungensis might not be properly assigned in the taxonomy. Phylogenetic, phenotypic and chemotaxonomic characterizations clearly showed that the genus Sphingorhabdus should be reclassified into two genera (Clade I and Clade II), for which the original genus name, Sphingorhabdus, is proposed to be retained only for Clade I, and a new genus named as Parasphingorhabdus gen. nov. is proposed for Clade II with four new combinations: Parasphingorhabdus marina comb. nov., Parasphingorhabdus litoris comb. nov., Parasphingorhabdus flavimaris comb. nov. and Parasphingorhabdus pacifica comb. nov. Moreover, Sphingopyxis baekryungensis should represent a novel genus in the family Sphingomonadaceae, for which the name Novosphingopyxis gen. nov. is proposed, with a combination of Novosphingopyxis baekryungensis comb. nov. The study provides a new insight into the taxonomy of closely related genera in the family Sphingomonadaceae.

Ramlibacter humi sp. nov., isolated from tropical forest soil.

A Gram-stain-negative, aerobic and non-motile strain, designated 18x22-1T, was isolated from a forest soil sample collected from Limushan Nature Reserve in Hainan Province, PR China. Growth occurred at 15-37 °C and pH 6.0-8.0 without NaCl. The 16S rRNA gene sequence analyses showed that strain 18x22-1T was closely related to Ramlibacter tataouinensis DSM 14655T (98.5 %), followed by Ramlibacter henchirensis DSM 14656T (97.9 %) and other Ramlibacter species and formed a stable cluster with R. tataouinensis DSM 14655T, R. henchirensis DSM 14656T, Ramlibacter solisilvae JCM 19319T and Ramlibacter rhizophilus CCTCC AB 2015357T. Results of chemotaxonomic analyses showed that ubiquinone-8 (Q-8) was the major respiratory quinone, and the major fatty acids (>10 % of the total amounts) were C16 : 0 and C17 : 0cyclo. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, two unidentified aminopholipids and four unidentified phospholipids. The draft genome sequence was 4.47 Mb long with a G+C content of 68.9 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain 18x22-1T and four closely related type strains were in the range of 79.3-82.3 % and 21.9-25.1 %, respectively. The results of phenotypic, phylogenetic and chemotaxonomic analyses supported that strain 18x22-1T represents a novel species of the genus Ramlibacter, for which the name Ramlibacterhumi sp. nov. is proposed. The type strain is 18x22-1T (=GDMCC 1.1584T=KCTC 52922T).

Lysobacter silvisoli sp. nov., isolated from forest soil.

A yellow-pigmented, Gram-stain-negative, gliding and rod-shaped bacterial strain, designated zong2l5T, was isolated from a forest soil sample at Dinghu Mountain, Guangdong Province, PR China. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain zong2l5T belongs to the genus Lysobacter, and was most closely related to Lysobacter enzymogenes KCTC 12131T (97.7 %) and Lysobacter soli KCTC 22011T (97.6 %). The novel strain showed an average nucleotide identity (ANI) value of 81.5 % and a digital DNA-DNA hybridization (dDDH) value of 25.3 % with L. enzymogenes KCTC 12131T based on draft genome sequences, followed by L. soli KCTC 22011T with ANI and dDDH values of 79.4 % and 22.7 %, respectively. The DNA G+C content of strain zong2l5T based on the whole genome sequence was 69.2 mol%. The major fatty acids were iso-C15 : 0, iso-C17 : 0 and summed feature 9 (iso-C17 : 1ω9c and/or 10-methyl C16 : 0). Strain zong2l5T contained Q-8 as the major isoprenoid quinone and the major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl-N-methylethanolamine, phosphatidylethanolamine, three unidentified phospholipids and an unidentified aminolipid. The phenotypic, genotypic and chemotaxonomic anlyses clearly showed that strain zong2l5T represents a novel species of the genus Lysobacter, for which the name Lysobactersilvisoli sp. nov. is proposed. The type strain is zong2l5T (=GDMCC 1.1489T=KCTC 52923T).

Emended descriptions of the species Sphingomonas adhaesiva Yabuuchi et al. 1990 and Sphingomonas ginsenosidimutans Choi et al. 2011.

During the phylogenetic study of the genus Sphingomonas and its closely related genera, we found that there existed errors in the 16S rRNA gene sequence of the type strain of the type species of Sphingomonas adhaesiva (D13722). Data suggested the wrong sequence should be replaced by the sequence under the accession number KY927401. As the new sequence shared 99.6 % 16S rRNA gene sequence similarity with that of Sphingomonas ginsenosidimutans, the relationship between these two species was reevaluated in the present study. Analyses, based on the whole genome sequences, phenotypic characteristics and fatty acid profiles clearly show that S. adhaesiva and Sphingomonas ginsenosidimutans are two distinct species of the genus Sphingomonas. Considering the errors in the original descriptions of S. adhaesiva and S. ginsenosidimutans, we have emended the descriptions of the two species.

Genome-based reclassification of Sphingopyxis ummariensis as a later heterotypic synonym of Sphingopyxis terrae, with the descriptions of Sphingopyxis terrae subsp. terrae subsp. nov. and Sphingopyxis terrae subsp. ummariensis subsp. nov.

During the phylogenetic analysis of the genus Sphingopyxis, we found that an incorrect 16S rRNA gene sequence (accession number: D13727) was provided in the original description of Sphingopyxisterrae NBRC 15098T and the wrong sequence has been adopted and used for a long time. It should be replaced by the new correct 16S rRNA gene sequence (accession number: MF618306). The new sequence shared the highest similarity (99.8 %) with that of Sphingopyxisummariensis DSM 24316T. The average nucleotide identity (ANI) (96.87 %) and digital DNA-DNA hybridization (75.30 %) values based on the whole-genome sequences and almost the same phenotypic and chemotaxonomic characteristics of the two type strains revealed thatSphingopyxisummariensis should be a later heterotypic synonym ofSphingopyxisterrae. However, the distinctions in the genome size, hydrolysis of aesculin, α-glucosidase and particularly the fatty acid profiles strongly support that strain DSM 24316T should be considered to represent a novel subspecies ofSphingopyxisterrae. Two novel subspecies are therefore proposed, namely Sphingopyxisterraesubsp. terrae subsp. nov. (type strain E-1-AT=NBRC 15098T=JCM 10195T=DSM 8831T=LMG 17326T) and Sphingopyxisterraesubsp. ummariensis subsp. nov. (type strain UI2T=DSM 24316T=CCM 7428T=MTCC 8591T).

Reclassification of Sphingopyxis contaminans as Sphingorhabdus contaminans comb. nov. and emended description of the genus Sphingorhabdus.

With the description of the genus Sphingorhabdus, the taxonomic position of Sphingopyxis contaminans was re-evaluated based on analyses of 16S rRNA gene sequences and phenotypic and chemotaxonomic characteristics. The results revealed that Sphingopyxis contaminans is clearly a member of the genus Sphingorhabdus and we proposed that Sphingopyxis contaminans(Subhash Y, Sasikala C, Ramana CV. Int J Syst Evol Microbiol 2014;64:2238-2243) should be reclassified as Sphingorhabduscontaminans comb. nov. An emended description of the genus Sphingorhabdus is also provided.

Sphingomonas spermidinifaciens sp. nov., a novel bacterium containing spermidine as the major polyamine, isolated from an abandoned lead-zinc mine and emended descriptions of the genus Sphingomonas and the species Sphingomonas yantingensis and Sphingomonas japonica.

A yellow-pigmented bacterial strain, designated 9NM-10T, was isolated from an abandoned lead-zinc mine in Meizhou, Guangdong Province, China. Cells were strictly aerobic, Gram-stain-negative and motile with a polar monotrichous flagellum. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain 9NM-10T belongs to the genus Sphingomonas and was most closely related to Sphingomonas yantingensis JCM 19201T and Sphingomonas japonica JCM 15438T. DNA-DNA relatedness values between strain 9NM-10T and these two type strains were 43.6±1.3 and 35.4±0.9 %, respectively. It contained Q-10 as the predominant respiratory quinone and the major cellular fatty acids were C18 : 1ω7c, C16 : 0, C17 : 1ω6c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The genomic DNA G+C content of strain 9NM-10T was 68.7±0.2 mol%. The polar lipids were sphingoglycolipid, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, diphosphatidylglycerol, an unidentified phospholipid and three unidentified lipids. Strain 9NM-10T contained spermidine as the major polyamine. On the basis of phenotypic, phylogenetic and chemotaxonomic analyses, strain 9NM-10T is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas spermidinifaciens sp. nov. is proposed. The type strain is 9NM-10T (=GDMCC 1.657T=DSM 27571T). Descriptions of the genus of Sphingomonas and the species Sphingomonas yantingensis and Sphingomonas japonica were also emended in this study.

Corynebacterium guangdongense sp. nov., isolated from a contaminated plate.

A novel Gram-reaction-positive, non-motile and facultatively anaerobic bacterium, designated strain S01T, was isolated from a nutrient agar plate kept on a laboratory clean bench at Guangdong Institute of Microbiology, PR China, which was contaminated from an unknown source. Strain S01T was found to be catalase-positive and oxidase-negative. Similarity searches revealed that the strain shared the highest 16S rRNA gene similarity with Corynebacterium humireducens MFC-5T (95.9 %). However, phylogenetic analysis based on the 16S rRNA gene sequences showed that strain S01T was closely related to Corynebacteriumdoosanense JCM 17317T (94.8 %) and Corynebacterium maris JCM 17018T (94.8 %). The major fatty acids were C18:1ω9c, C16:0, 10-methyl C18:0 and C18:0. The respiratory quinones predominantly consisted of MK-8(H2), with small amounts of MK-8 and MK-9(H2). Polar lipids contained phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, an unidentified aminolipid, two unidentified glycolipids and two unidentified lipids. Mycolic acids were present. The cell-wall peptidoglycan contained meso-diaminopimelic acid and the major cell-wall sugars were galactose, arabinose and glucose. The genomic DNA G+C content of strain S01T was 70.7±0.1 mol%. The results of phenotypic, phylogenetic and chemotaxonomic analyses indicated that strain S01T represents a novel species of the genus Corynebacterium, for which the name Corynebacterium guangdongense sp. nov. is proposed. The type strain is S01T (=GDMCC 1.1022T=CCTCC AB 2015423T=KCTC 39608T).

Sphingomonas metalli sp. nov., isolated from an abandoned lead-zinc mine.

A Gram-stain-negative and non-motile bacterial strain designated 9O-5T was isolated from an abandoned lead-zinc mine in Meizhou, Guangdong Province, southern China. The isolate was orange-pigmented, aerobic, and oxidase- and catalase-positive. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain 9O-5T belongs to the genus Sphingomonas and was closely related to Sphingomonas abaci DSM 15867T (97.6 % similarity), Sphingomonas phyllosphaerae FA2T (96.9 %) and Shingomonas guangdongensis 9NM-8T (96.8 %). Mean DNA-DNA relatedness between strain 9O-5T and S. abaci DSM 15867T was only 47.1 ± 4.9 %. The major fatty acids were C18 : 1ω7c, C14 : 0 2-OH and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). It contained Q-10 as the predominant respiratory quinone and sym-homospermidine as the major polyamine. The polar lipids were sphingoglycolipid, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, five unidentified phospholipids and six unidentified lipids. The genomic DNA G+C content of strain 9O-5T was 69.1 ± 0.1 mol%. Based on the data from this polyphasic taxonomic study, strain 9O-5T should be considered as representing a novel species of the genus Sphingomonas, for which the name Sphingomonas metalli sp. nov. is proposed. The type strain is 9O-5T ( = CGMCC 1.15330T = KCTC 42759T).

Massilia putida sp. nov., a dimethyl disulfide-producing bacterium isolated from wolfram mine tailing.

A heavy metal-resistant and dimethyl disulfide-producing bacterial strain, designated 6NM-7T, was isolated from wolfram mine tailing, Dayu County, Jiangxi Province, PR China. Strain 6NM-7T was aerobic, Gram-stain-negative and motile by means of a single polar flagellum. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain 6NM-7T was affiliated with the genus Massilia and was closely related to Massilia norwichensis LMG 28164T (98.8 % 16S rRNA gene sequence similarity), Massilia kyonggiensis KACC 17471T (98.4 %), Massilia niastensis KACC 12599T (97.8 %), Massilia tieshanensis KACC 14940T (97.3 %), Massilia haematophila KACC 13771T (97.2 %), Massilia namucuonensis CGMCC 1.11014T (97.1 %) and Massilia aerilata KACC 12505T (97.1 %). The DNA-DNA relatedness values between strain 6NM-7T and its closely related type strains were all below 70 %. The major respiratory quinone was unbiquinone 8 (Q-8) and the major cellular fatty acids consisted of C16 : 0 (33.2 %), summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH; 21.8 %), C17 : 0 cyclo (20.8 %), C18 : 1ω7c (7.4 %) and C10 : 0 3-OH (5.8 %). The major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The genomic DNA G+C content of strain 6NM-7T was 66.8 ± 0.6 mol%. On the basis of the results of this polyphasic taxonomic study, strain 6NM-7T should be assigned to a novel species of the genus Massilia, for which the name Massilia putida sp. nov. is proposed. The type strain is 6NM-7T ( = DSM 27523T = KCTC 42761T).

Lysobacter mobilis sp. nov., isolated from abandoned lead-zinc ore.

An aerobic and Gram-stain-negative bacterial strain, designated 9NM-14(T), was isolated from abandoned lead-zinc ore from Meizhou, Guangdong Province, south China. Strain 9NM-14(T) was motile by means of a single polar flagellum. Phylogenetic analysis, based on 16S rRNA gene sequences, showed that strain 9NM-14(T) was affiliated with the genus Lysobacter and was most closely related to Lysobacter xinjiangensis RCML-52(T) and Lysobacter bugurensis ZLD-29(T) (97.4 % and 96.3 % 16S rRNA gene sequence similarity, respectively). The DNA-DNA relatedness value between strain 9NM-14(T) and L. xinjiangensis RCML-52(T) was 30.1±7.6 %. The major respiratory quinone was unbiquinone 8 (Q-8) and the major cellular fatty acids consisted of iso-C17 : 1ω9c (29.1 %), iso-C15 : 0 (28.9 %), iso-C17 : 0 (9.4 %), iso-C16 : 0 (8.6 %), iso-C11 : 0 3-OH (6.9 %) and iso-C11 : 0 (5.8 %). The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, an unidentified aminolipid and five unidentified phospholipids. The genomic DNA G+C content of strain 9NM-14(T) was 70.7±0.1 mol%. On the basis of the data from this polyphasic taxonomic study, strain 9NM-14(T) should be assigned to a novel species of the genus Lysobacter, for which the name Lysobacter mobilis sp. nov. is proposed. The type strain is 9NM-14(T) ( = GIMCC 1.659(T) = CCTCC AB 2014273(T) = DSM 27574(T)).

Acinetobacter guangdongensis sp. nov., isolated from abandoned lead-zinc ore.

A Gram-stain-negative, non-motile bacterial strain designated 1NM-4(T) was isolated from an abandoned lead-zinc ore mine site in Mei County, Meizhou, Guangdong Province, southern China. The isolate was light yellow, strictly aerobic, oxidase-negative and catalase-positive. Phylogenetic analyses based on 16S rRNA, rpoB and gyrB gene sequences, together with DNA-DNA hybridization values less than 70%, revealed that strain 1NM-4(T) belongs to the genus Acinetobacter and may represent a novel species. The major respiratory quinone was ubiquinone 9 (Q-9) and the major cellular fatty acids consisted of C18:1ω9c, summed feature 3 (C16:1ω7c and/or C16:1ω6c), C16:0 and C12:0. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, an unidentified aminolipid and two unidentified phospholipids. The genomic DNA G+C content of strain 1NM-4(T) was 47.17 ± 0.02 mol%. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain 1NM-4(T) should be assigned to a novel species of the genus Acinetobacter, for which the name Acinetobacter guangdongensis sp. nov. is proposed. The type strain is 1NM-4(T) ( = GIMCC 1.656(T) = CCTCC AB 2014199(T) = KCTC 42012(T)).

Sphingomonas gimensis sp. nov., a novel Gram-negative bacterium isolated from abandoned lead-zinc ore mine.

A novel bacterial strain designated 9PNM-6(T) was isolated from an abandoned lead-zinc ore mine site in Meizhou, Guangdong Province, China. The isolate was found to be Gram-negative, rod-shaped, orange-pigmented, strictly aerobic, oxidase- and catalase-positive. Growth occurred at 0-4 % NaCl (w/v, optimum, 0 %), at pH 6.0-8.0 (optimum, pH 7.0) and at 15-32 °C (optimum, 28-30 °C). Phylogenetic analysis based on 16S rRNA gene sequence similarities showed that strain 9PNM-6(T) belongs to the genus Sphingomonas, with the highest sequence similarities with Sphingomonas jejuensis NBRC 107775(T) (99.7 %), Sphingomonas koreensis KCTC 2882(T) (95.1 %) and Sphingomonas dokdonesis KCTC 12541(T) (95.1 %). The chemotaxonomic characteristics of strain 9PNM-6(T) were consistent with those of the genus Sphingomonas. The predominant respiratory quinone was identified as ubiquinone Q-10, the major polyamine as sym-homospermidine, and the major cellular fatty acids as C18:1 ω7c, C16:0, C16:1 ω7c and/or C16:1 ω6c and C14:0 2-OH. The major polar lipids are sphingoglycolipid, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatideylcholine, an unidentified phospholipid and four unidentified aminolipids. The genomic DNA G+C content of strain 9PNM-6(T) was determined to be 69.2 ± 0.6 mol%. Based on comparative analyses of morphological, physiological and chemotaxonomic data, and levels of DNA-DNA relatedness values, strain 9PNM-6(T) is considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas gimensis sp. nov. (Type strain 9PNM-6(T) = GIMCC 1.655(T) = CGMCC 1.12671(T) = DSM 27569(T)) is proposed.

Description of a Gram-negative bacterium, Sphingomonas guangdongensis sp. nov.

A Gram-stain-negative bacterial strain, designated 9NM-8T, was isolated from an abandoned lead-zinc ore in Mei county, Meizhou, Guangdong province, PR China. The isolate was orange-pigmented, aerobic, oxidase- and catalase-positive, motile with lophotrichous flagella and rod-shaped. Strain 9NM-8T grew optimally at pH 7.0 and 30 °C and in the absence of NaCl on R2A agar. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain 9NM-8T belongs to the genus Sphingomonas, with highest sequence similarities to Sphingomonas azotifigens KACC 14484T (96.1%), Sphingomonas trueperi DSM 7225T (96.0%) and Sphingomonas pituitosa DSM 13101T (95.6 %). Strain 9NM-8T contained Q-10 as the predominant ubiquinone. The major fatty acids included C18:1ω7c, C16:0, C16:1ω7c and/or C16 : 1ω6c (summed feature 3) and 11-methyl C18:1ω7c. The DNA G+C content was 69.6±1.3 mol%. The major component in the polyamine pattern was sym-homospermidine and the polar lipid profile contained sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, an unidentified glycolipid and two unidentified phospholipids. Based on comparative analysis of physiological, chemotaxonomic and phylogenetic characteristics, strain 9NM-8T should be considered to represent a novel species of the genus Sphingomonas, for which the name Sphingomonas guangdongensis sp. nov. is proposed. The type strain is 9NM-8T (=GIMCC 1.653T=CGMCC 1.12672T=DSM 27570T).

Streptomyces caeruleatus sp. nov., with dark blue diffusible pigment.

An actinomycete, designated strain GIMN4.002(T), was isolated from a tomato rhizosphere soil sample in Guangzhou, China. The strain produces white aerial mycelium and dark blue diffusible pigment on Gause's synthetic agar, and microscopic observation revealed that it produces looped chains of spiny spores. Morphological and chemotaxonomic characteristics of the strain are typical of the genus Streptomyces. Melanin was produced and antibacterial activity was detected against Gram-positive micro-organisms, such as Bacillus subtilis, Micrococcus luteus and Staphylococcus aureus. The 16S rRNA gene sequence of strain GIMN4.002(T) had highest similarity (99.4  %) to Streptomyces lincolnensis B91; however, DNA-DNA relatedness between strain GIMN4.002(T) and S. lincolnensis NBRC 13054(T) was only 32.17  %. Further, the morphological, physiological and biochemical characteristics of strain GIMN4.002(T) are distinct from S. lincolnensis and other species of the genus Streptomyces with which this strain has high 16S rRNA gene sequence similarity (98-99  %). On the basis of the physiological and molecular properties observed, it is proposed that strain GIMN4.002(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces caeruleatus sp. nov. is proposed, with GIMN4.002(T) (=CCTCC M 208213(T) =NRRL B-24802(T)) as the type strain.

Streptomyces lacticiproducens sp. nov., a lactic acid-producing streptomycete isolated from the rhizosphere of tomato plants.

A novel actinomycete, designated strain GIMN4.001(T), was isolated from the rhizosphere of tomato plants grown in Guangzhou, China. The strain produced greyish white aerial mycelia, lactic acid and a large quantity of double diamond-shaped crystals on potato dextrose agar and yeast extract-malt extract agar. The colour of the substrate mycelium was not sensitive to pH. Microscopic observations revealed that strain GIMN4.001(T) produced verticillate chains of cylindrical spores. Chemotaxonomic data confirmed that strain GIMN4.001(T) belonged to the genus Streptomyces. Melanin pigments were not produced. No antibacterial activity was observed against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis or Candida albicans, but inhibitory activity was observed against Penicillium citrinum. 16S rRNA gene sequence analysis revealed that strain GIMN4.001(T) was related most closely to Streptomyces morookaense ATCC 19166(T) (98.9 % similarity) and Streptomyces lavenduligriseus ATCC 13306(T) (98.7 %). Levels of DNA-DNA relatedness between strain GIMN4.001(T) and the type strains of these species were low (14-20 %). Furthermore, strain GIMN4.001(T) could be differentiated from S. morookaense, S. lavenduligriseus and other closely related species of the genus Streptomyces based on morphological, physiological and biochemical characteristics. On the basis of its physiological and molecular properties, strain GIMN4.001(T) is considered to represent a novel species of the genus Streptomyces, for which the name Streptomyces lacticiproducens sp. nov. is proposed. The type strain is GIMN4.001(T) (=CCTCC M208214(T)=NRRL B-24800(T)).

Microbacterium radiodurans sp. nov., a UV radiation-resistant bacterium isolated from soil.

Strain GIMN 1.002(T), a UV radiation-tolerant bacterium, was isolated from the upper sand layers of the Gobi desert, Xinjiang, China and characterized in order to determine its taxonomic position. Cells were Gram-reaction-positive, heterotrophic, strictly aerobic, short rods. 16S rRNA gene sequence analysis revealed that strain GIMN 1.002(T) belonged to the genus Microbacterium and was closely related to Microbacterium arborescens DSM 20754(T) (98.8 % 16S rRNA gene sequence similarity) and Microbacterium imperiale DSM 20530(T) (98.7 %). However, strain GIMN 1.002(T) had low DNA-DNA relatedness with M. arborescens DSM 20754(T) (17.1 %) and M. imperiale DSM 20530(T) (12.89 %). Strain GIMN 1.002(T) possessed chemotaxonomic markers that were consistent with its classification in the genus Microbacterium, i.e. MK-11, MK-12 and MK-10 as major menaquinones and anteiso-C(15 : 0) (38.67 %), iso-C(16 : 0) (18.16 %) and iso-C(15 : 0) (17.46 %) as predominant cellular fatty acids. The DNA G+C content was 67.74 mol%. The cell-wall sugar was rhamnose. On the basis of the data from this study, strain GIMN 1.002(T) represents a novel species of the genus Microbacterium, for which the name Microbacterium radiodurans sp. nov. is proposed. The type strain is GIMN 1.002(T) (=CCTCC M208212(T) =NRRL B-24799(T)).

Streptomyces vietnamensis sp. nov., a streptomycete with violet blue diffusible pigment isolated from soil in Vietnam.

An actinomycete, designated strain GIMV4.0001(T), was isolated from a forest soil sample in Vietnam. It produced white aerial mycelium and violet-blue diffusible pigment on Gause's synthetic agar. The substrate mycelium colour was not sensitive to pH. Micoscopic observations revealed that strain GIMV4.0001(T) produced long, straight chains of cylindrical spores, and chemotaxonomic data confirmed that it belongs to the genus Streptomyces. Melanin was produced, but no antibacterial activity was evident against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans or Penicillium citrinum. Analysis of the 16S rRNA gene sequence of strain GIMV4.0001(T) revealed that the highest similarity (99.4 %) was to Streptomyces bikiniensis ATCC 11062(T). However, the DNA-DNA relatedness between strain GIMV4.0001(T) and S. bikiniensis ATCC 11062(T) was found to be 50.3 %. Strain GIMV4.0001(T) could also be differentiated from S. bikiniensis ATCC 11062(T) and other Streptomyces species showing high 16S rRNA gene sequence similarity (98-99 %) based on morphological, physiological and biochemical characteristics. On the basis of its physiological and molecular properties, it is evident that strain GIMV4.0001(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces vietnamensis sp. nov. is proposed. The type strain is GIMV4.0001(T) (=CCTCC M 205143(T)=IAM 15340(T)).