Distribution of Extended-Spectrum-ß-Lactamase-Producing Diarrheagenic Escherichia coli Clonal Complex 10 Isolates from Patients with Diarrhea in the Republic of Korea.

ESBL-producing E. coli is a public health concern in healthcare settings and the community. Between 2009 and 2018, a total of 187 ESBL-producing pathogenic E. coli isolates were identified, and clonal complex (CC) 10 was the predominant clone (n = 57). This study aimed to characterize the ESBL-producing pathogenic E. coli CC10 strains obtained from patients with diarrhea to improve our understanding of CC10 distribution in the Republic of Korea. A total of 57 CC10 strains were selected for comprehensive molecular characterization, including serotype identification, the analysis of antibiotic resistance genes, the investigation of genetic environments, the determination of plasmid profiles, and the assessment of genetic correlations among CC10 strains. Among the CC10 isolates, the most prevalent serotype was O25:H16 (n = 21, 38.9%), followed by O6:H16 (10, 19.6%). The most dominant ESBL genes were blaCTX-M-15 (n = 31, 55%) and blaCTX-M-14 (n = 15, 27%). Most blaCTXM genes (n = 45, 82.5%) were located on plasmids, and these incompatibility groups were confirmed as IncB/O/K/Z, IncF, IncI1, and IncX1. The mobile elements located upstream and downstream mainly included ISEcp1 (complete or incomplete) and IS903 or orf477. Phylogenetic analysis showed that the CC10 strains were genetically diverse and spread among several distinct lineages. The results of this study show that ESBL-producing pathogenic E. coli CC10 has been consistently isolated, with CTX-M-15-producing E. coli O25:H16 isolates being the major type associated with the distribution of CC10 clones over the past decade. The identification of ESBL-producing pathogenic E. coli CC10 isolates underscores the possible emergence of resistant isolates with epidemic potential within this CC. As a result, continuous monitoring is essential to prevent the further dissemination of resistant ESBL-producing E. coli CC10 strains.

Interference-free, lightweight wireless neural probe system for investigating brain activity during natural competition.

Competition is one of the most fundamental, yet complex, conflicts between social animals, and previous studies have indicated that the medial prefrontal cortex (mPFC) region of a brain is involved in social interactions. However, because we do not have a lightweight, wireless recording system that is free of interference, it is still unclear how the neural activity of the mPFC region is involved in the diverse, interacting behaviors that comprise competition. Herein, we present an interference-free, lightweight, wireless neural probe system that we applied to two mice to measure mPFC neural activities during a food competition test. In the test, we categorized 18 behavioral repertoires expressed by the mice. From the analysis of the neural signals during each repetition of the test, we found that the mPFC neural activity had the most positive correlation with goal-driven competitive behaviors, such as guarding resources and behaviors related to the extortion of resources. Remarkably, we found that the neural activity associated with guarding behavior was higher than that of extorting behavior, and this highlighted the importance of resource-guarding behavior for winning the competition, i.e., 'winning a trophy is hard, but keeping it is harder'. Our approach in which a wireless system is used will enable in-depth studies of the brains of mice in their natural social interactions.

Parasphingopyxis marina sp. nov. isolated from coastal seawater.

A Gram-stain-negative, aerobic, yellow-pigmented and non-motile rod-shaped bacterium, designated as GrpM-11T, was isolated from coastal seawater collected from the East Sea, Republic of Korea. Strain GrpM-11T could grow at 10-40 °C (optimum, 35 °C), at pH 5.5-9.5 (optimum, pH 7.0) and in the presence of 0-8 % (w/v) NaCl (optimum, 3-4 %). Cells hydrolysed aesculin, gelatin and casein, but could not reduce nitrate to nitrite. The 16S rRNA gene sequence analysis showed that this strain formed a distinct phylogenic lineage with Parasphingopyxis algicola ATAX6-5T (96.2 % sequence identity) and Parasphingopyxis lamellibrachiae DSM 26725T (96.2 % identity) and belonged to the genus Parasphingopyxis. The predominant isoprenoid quinone was ubiquinone-10. The polar lipid profile of strain GrpM-11T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid and three unknown glycolipids. Cellular fatty acid analysis indicated that summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 42.8 %), C16 : 0 (19.0 %), C18 : 1 ω7c 11-methyl (13.3 %) and C18 : 1 ω7c (8.0 %) were the major fatty acids. The DNA G+C content of strain GrpM-11T was 63.7 mol%. Through whole genome sequence comparisons, the digital DNA-DNA hybridization and average nucleotide identity values between strain GrpM-11T and two species of the genus Parasphingopyxis were revealed to be in the ranges of 19.0-22.0 % and 76.3-79.7 %, respectively. Based on the results of polyphasic analysis, strain GrpM-11T represents a novel species of the genus Parasphingopyxis, for which the name Parasphingopyxis marina sp. nov. is proposed. The type strain is GrpM-11T (KCCM 43343T=JCM 34665T).

Pelagicola marinus sp. nov. isolated from deep-sea water.

A Gram-stain-negative, strictly aerobic, non-motile, rod-shaped bacterial strain, designated strain DSW4-44T, was isolated from deep-sea water from the East Sea of Korea. The optimum temperature and pH for growth were 25 °C and pH 7.5. DSW4-44T grew with 1.0-6.0 % NaCl, having optimum growth at 3-4 %. Phylogenetic analyses based on 16S rRNA gene sequences indicated that DSW4-44T represented a member of the class Alphaproteobacteria and was most closely related to Pelagicola litoralis CL-ES2T and Pelagicola litorisediminis D1-W8T, with similarities of 96.5 and 95.6 %, respectively. The major fatty acid was summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). The polar lipids of DSW4-44T were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminolipid, two unidentified lipids and three unidentified phospholipids. The isoprenoid quinone was Q-10. The DNA G+C content of DSW4-44T was 54.3 mol%. On the basis of evidence from a polyphasic study, strain DSW4-44T represent a novel species of the genus Pelagicola, for which the name Pelagicola marinus sp. nov. is proposed. The type strain is DSW4-44T (=KCTC 62762T=KCCM 43261T=JCM 33637T).

Zhongshania marina sp. nov., isolated from deep-sea water.

A Gram-stain-negative, aerobic, catalase-positive, oxidase-positive, motile by a single polar flagellum, rod-shaped strain, designated DSW25-10T, was isolated from the deep-sea water of the East Sea, Republic of Korea. Strain DSW25-10Tgrew at 4-35 °C (optimum, 20-35 °C), at pH 5.5-9.0 (optimum, pH 7.0) and in the presence of 0-6.0 % NaCl (optimum, 0.5-2 %), and could assimilate valerate, but not assimilate d-mannitol and 3-hydroxy-butyrate. Comparative 16S rRNA gene sequence analysis showed that strain DSW25-10T belongs to the genus Zhongshania in the family Spongiibacteraceae and is most closely related to Zhongshania guokunii ZS6-22T, Zhongshania borealis CL-AS9T, Zhongshania aliphaticivorans SM-2T and Zhongshani antarctica ZS5-23T with a similarities of 97.1, 97.0, 96.7 and 96.6 %, respectively. The G+C content of genomic DNA was 49.1 mol% and the major respiratory quinone was ubiquinone-8. Phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol were identified as the major cellular polar lipids. The predominant cellular fatty acids in strain DSW25-10T were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0 and C17 : 1ω8c. The DNA-DNA relatedness values between strain DSW25-10T and related strains were clearly lower than 70 %. On the basis of evidence from a polyphasic analysis, strain DSW25-10T is proposed to represent a novel species, Zhongshania marina sp. nov. The type strain is DSW25-10T (=KCCM 43273T=JCM 17372T).

Genome sequencing to develop Paenibacillus donghaensis strain JH8T (KCTC 13049T=LMG 23780T) as a microbial fertilizer and correlation to its plant growth-promoting phenotype.

Paenibacillus donghaensis JH8T (KCTC 13049T=LMG 23780T) is a Gram-positive, mesophilic, endospore-forming bacterium isolated from East Sea sediment at depth of 500m in Korea. The strain exhibited plant cell wall hydrolytic and plant growth promoting abilities. The complete genome of P. donghaensis strain JH8T contains 7602 protein-coding sequences and an average GC content of 49.7% in its chromosome (8.54Mbp). Genes encoding proteins related to the degradation of plant cell wall, nitrogen-fixation, phosphate solubilization, and synthesis of siderophore were existed in the P. donghaensis strain JH8T genome, indicating that this strain can be used as an eco-friendly microbial agent for increasing agricultural productivity.

Pseudoxanthomonas putridarboris sp. nov. isolated from rotten tree.

A Gram-staining-negative, rod-shaped, motile bacterium, designated WD12T, was isolated from a rotten tree at Chungbuk National University, South Korea. WD12T grew optimally at 30-37 °C and pH 7.0-7.5 and could assimilate arbutin and potassium-5-ketogluconate. The major cellular fatty acid were iso-C16 : 0, C16 : 0, cyclo C17 : 0, iso-C15 : 0, summed features 3 (comprising C16 : 1ω7c/iso-C15 : 0 2-OH) and anteiso-C15 : 0. The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major respiratory quinone was ubiquinone-8 (Q-8). The G+C content of the genomic DNA was 69.1 %. The results of phylogenetic and comparative analysis based on the 16S rRNA gene sequence indicated that WD12T formed a tight phylogenetic lineage with Pseudoxanthomonas mexicana AMX 26BT and Pseudoxanthomonas japonensis 12-3T of the the genus Pseudoxanthomonas in the family Xanthomonadaceae. Sequence similarity to other members of the genus Pseudoxanthomonasranged from 98.6 % (P. mexicana AMX 26BT) to 95.1 % (Pseudoxanthomonas taiwanensis CB-226T). DNA-DNA relatedness between WD12T and eight type strains of species of the genus Pseudoxanthomonasshowing more than 97 % 16S rRNA sequence similarity were 6±0-26±1 %. On the basis of the evidence from this polyphasic study, WD12T represents a novel species of the genus Pseudoxanthomonas, for which the name Pseudoxanthomonas putridarboris sp. nov. is proposed. The type strain is WD12T (=KACC 15045T=LMG 25968T).

Winogradskyella pulchriflava sp. nov., isolated from marine sediment.

A taxonomic study was conducted on strain EM106(T), isolated from a sediment sample of the East Sea, Republic of Korea. Comparative 16S rRNA gene sequence analyses showed that strain EM106(T) belongs to the family Flavobacteriaceae and is most closely related to Winogradskyella echinorum KMM 6211(T) and Winogradskyella ulvae KMM 6390(T) (97.8 and 97.3 % 16S rRNA gene sequence similarities, respectively). The G+C content of the genomic DNA of strain EM106(T) was 33.3 mol%, and the major respiratory quinone was menaquinone-6. The polar lipids of EM106(T) were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. DNA-DNA relatedness data indicated that strain EM106(T) represented a distinct species, separate from W. echinorum KMM 6211(T) and W. ulvae KMM 6390(T). Strain EM106(T) possessed iso-C15 : 0, iso-C15 : 1 G and iso-C16 : 0 3-OH as the major cellular fatty acids. The isolate was Gram-staining-negative, strictly aerobic, short rod-shaped and motile by gliding. The strain grew at 10-35 °C (optimum, 25 °C), pH 6.5-9.0 (optimum, 7.5), and with 0.5-5 % (w/v) NaCl (optimum, 0.5-1 % NaCl). The overall physiological features of strain EM106(T) were very similar to those of W. echinorum KMM 6211(T) but only strain EM106(T) had nitrate reductase activity. On the basis of phenotypic and phylogenetic analyses, strain EM106(T) is proposed to represent a novel species, Winogradskyella pulchriflava. The type strain is EM106(T)( = KCTC 23858(T) = NCAIM B 02481(T)).

Phenylobacterium muchangponense sp. nov., isolated from beach soil, and emended description of the genus Phenylobacterium.

A Gram-staining-negative, non-motile, aerobic bacterium, designated strain A8T, was isolated from the beach soil of Muchangpo, Korea. Cells were rod-shaped (0.5-0.6×0.7-1.3 µm) and colonies were colourless, circular with entire edges and had a glistening surface. The isolate grew optimally at 25-35 °C and did not require NaCl for growth. Strain A8T could not assimilate acetate, DL-lactate, succinate, antipyrine or chloridazon, but weakly assimilated L-phenylalanine. Major fatty acids were summed feature 7 (comprising C18:1ω7c/ω9t/ω12t), C16:0 and summed feature 4 (comprising C16:1ω7c/ iso-C15:0 2-OH). The major isoprenoid quinone was ubiquinone-10 and the DNA G+C content was 72.3 mol%. Comparative 16S rRNA gene sequence studies showed that strain A8T belonged to the family Caulobacteraceae, class Alphaproteobacteria and was most closely related to type strains of members of the genus Phenylobacterium (95.7-97.1 % similarity). Signature nucleotides and phylogenetic analysis of the 16S rRNA gene sequence also suggested that strain A8T was affiliated with the genus Phenylobacterium. Low DNA-DNA relatedness values (3.0±1.8-11.5±3.2 %) indicated that strain A8T represented a distinct species that was separated from other type strains in the genus Phenylobacterium. On the basis of evidence from a polyphasic study, it is proposed that strain A8T (=KACC 15042T=LMG 25973T) represents the type strain of a novel species, Phenylobacterium muchangponense sp. nov. An emended description of the genus Phenylobacterium is also presented.

Salinisphaera orenii sp. nov., isolated from a solar saltern.

A taxonomic study was performed on two isolates, designated strains MK-B5(T) and MK-B7, isolated from sediment of a solar saltern pond in Gomso Bay, Republic of Korea. Comparative 16S rRNA gene sequence analysis showed that strains MK-B5(T) and MK-B7 belong to the Gammaproteobacteria and are related most closely to Salinisphaera shabanensis JCM 11575(T) ( = E1L3A(T)) (96.3 and 96.5% similarity, respectively), Salinisphaera dokdonensis KCCM 90064(T) ( = CL-ES53(T)) (95.6 and 95.6%) and Salinisphaera hydrothermalis JCM 115514(T) ( = EPR70(T)) (95.1 and 95.3%). The level of 16S rRNA gene sequence similarity between strains MK-B5(T) and MK-B7 was 99.8%. The G+C contents of their genomic DNAs were 63.4 and 63.6 mol%, respectively, and the major respiratory quinone was ubiquinone-8. DNA-DNA relatedness between strains MK-B5(T) and MK-B7 was 98%, indicating that the two isolates represent a single species. However, the level of DNA-DNA relatedness between the two isolates and S. shabanensis E1L3A(T) (26.4-30.8%) indicates that they represent a novel species. Strains MK-B5(T) and MK-B7 possessed C(14:0), C(16:0) and C(19:0)ω8c cyclo as major fatty acids. The two isolates were Gram-stain-negative, strictly aerobic, short rod-shaped and motile. They grew at 10-40 °C (optimum, 35-37 °C), at pH 5.0-8.5 (optimum, 7.0-7.5) and with 5-25% (w/v) NaCl (optimum, 15% NaCl). On the basis of phenotypic and phylogenetic analyses, strains MK-B5(T) and MK-B7 are thus considered to represent a novel species of the genus Salinisphaera, for which the name Salinisphaera orenii sp. nov. is proposed. The type strain is MK-B5(T) ( = KCTC 23198(T) = JCM 17073(T)).

Shewanella arctica sp. nov., an iron-reducing bacterium isolated from Arctic marine sediment.

Two strains of dissimilatory iron-reducing bacteria, which could couple lactate oxidation to iron reduction for energy conservation, were isolated from Arctic marine sediment. The strains, IR12(T) and IR26, were both Gram-staining-negative, catalase- and oxidase-positive and facultative anaerobes. Their cells were rod-shaped and motile by means of a polar flagellum. Both strains grew in the presence of 0.5-3.5 % (w/v) NaCl, with an absolute requirement for Na(+). Both were psychrotolerant since they could grow at 4-28 °C but had an optimum growth temperature of 20 °C. Both grew at pH 4.5-9.0 (optimum, pH 7.5). The major fatty acids of strains IR12(T) and IR26 were summed feature 3 (C(16 : 1)ω6c and/or C(16 : 1)ω7c) and C(16 : 0). Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains IR12(T) and IR26 belonged to the class Gammaproteobacteria and were most closely related to Shewanella vesiculosa M7(T), Shewanella livingstonensis NF22(T) and Shewanella frigidimarina ACAM 591(T) (with 98.5 and 98.8 %, 98.5 and 98.8 %, and 98.5 and 98.8 % sequence similarities, respectively). The genomic DNA G+C contents of strains IR12(T) and IR26 were 40.0 and 40.3 mol%, respectively. DNA-DNA relatedness data indicated that the two novel strains represented a single species that was distinct from S. vesiculosa M7(T), S. livingstonensis NF22(T) and S. frigidimarina ACAM 591(T). Based on the phylogenetic, phenotypic and DNA-DNA relatedness data, the two new strains represent a single novel species of the genus Shewanella, for which the name Shewanella arctica sp. nov. is proposed. The type strain is IR12(T) ( = KCTC 23109(T) = JCM 16723(T)).

Thioalbus denitrificans gen. nov., sp. nov., a chemolithoautotrophic sulfur-oxidizing gammaproteobacterium, isolated from marine sediment.

A mesophilic, facultatively anaerobic, autotrophic bacterium, designated strain Su4(T), was isolated from marine sediment. The isolate was able to utilize reduced sulfur compounds including thiosulfate, tetrathionate, sulfur and sulfide but not sulfite as the energy source. Growth occurred under aerobic and denitrifying chemolithoautotrophic conditions in the presence of thiosulfate as an electron donor and bicarbonate as a carbon source. The G+C content of the genomic DNA was 64.5 mol%. Comparative 16S rRNA gene sequence studies showed that strain Su4(T) was clearly affiliated with the class Gammaproteobacteria. The isolate was Gram-negative-staining and rod-shaped, lacked flagella and grew in artificial seawater medium at 10-40 °C (optimum 28-32 °C) and in 1-5 % (w/v) NaCl (optimum 3 % NaCl). Strain Su4(T) possessed C16:0, C16:1ω7c/iso-C15:0 2-OH and C18:1ω7c/ω9t/ω12t as the major fatty acids. On the basis of phenotypic and phylogenetic analysis, the isolate represents a novel species of a novel genus, for which the name Thioalbus denitrificans is proposed. The type strain is Su4(T) ( = KCTC 5699(T)  = JCM 15568(T)).

Reichenbachiella faecimaris sp. nov., isolated from a tidal flat, and emended descriptions of the genus Reichenbachiella and Reichenbachiella agariperforans.

A taxonomic study was carried out on two bacterial strains, PCP11(T) and PCP104, isolated from a tidal flat of the Yellow Sea, Korea. Comparative 16S rRNA gene sequence studies showed that these strains belonged to the family Cytophagaceae, phylum Bacteroidetes. Strains PCP11(T) and PCP104 shared 99.4 % sequence similarity and were related most closely to Reichenbachiella agariperforans KMM 3525(T) (95.8 and 96.0 % sequence similarity, respectively). Members of the genera Fulvivirga, Roseivirga, Fabibacter and Marinoscillum were the next closest relatives of the new isolates, with sequence similarities ≤ 91 %. The two isolates were Gram-staining-negative, strictly aerobic, gliding bacteria. They grew in the presence of 1-5 % NaCl, at pH 5.5-8.5 and at 4-35 °C. Strains PCP11(T) and PCP104 shared a number of physiological and biochemical properties with Reichenbachiella agariperforans KMM 3525(T), but they differed from this strain in the hydrolysis of biopolymers and in the production of carotenoid and flexirubin-type pigments. Both strains possessed iso-C(15 : 0), summed feature 4 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH) and C(15 : 0) as major cellular fatty acids. The major respiratory quinone was menaquinone 7 (MK-7). The G+C contents of the genomic DNA of strains PCP11(T) and PCP104 were 39.6 and 41.9 mol%, respectively. On the basis of phenotypic data and phylogenetic inference, it is proposed that the two isolates represent a novel species, Reichenbachiella faecimaris sp. nov., with strain PCP11(T) ( = KACC 14523(T)  = JCM 16588(T)) as the type strain. Emended descriptions of the genus Reichenbachiella and Reichenbachiella agariperforans are also proposed.

Pseudoalteromonas donghaensis sp. nov., isolated from seawater.

A Gram-negative, rod-shaped, motile and aerobic bacterium, designated strain HJ51(T), was isolated from a seawater sample from the East Sea, near South Korea. The isolate grew slowly at 4 °C, was able to grow at 40 °C, required NaCl and grew optimally at pH 6.5-7.0. The G+C content of the genomic DNA was 41.8 mol%. The major fatty acids were summed feature 4 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), C(16 : 0) and summed feature 7 (C(18 : 1)ω7c, C(18 : 1)ω9t and/or C(18 : 1)ω12t). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain HJ51(T) belonged to the genus Pseudoalteromonas and had 91.7-98.9 % 16S rRNA gene sequence similarity with type strains of species of the genus Pseudoalteromonas. Strain HJ51(T) had 7.2 % DNA-DNA relatedness with Pseudoalteromonas mariniglutinosa DSM 15203(T) and 12.9 % with Pseudoalteromonas prydzensis DSM 14232(T). On the basis of the phenotypic, phylogenetic and genomic data, strain HJ51(T) represents a novel species of the genus Pseudoalteromonas, for which the name Pseudoalteromonas donghaensis sp. nov. is proposed. The type strain is HJ51(T) (=KCTC 22219(T)=LMG 24469(T)).

Flavobacterium chungbukense sp. nov., isolated from soil.

A yellow-pigmented, Gram-staining-negative, non-motile, strictly aerobic and rod-shaped bacterium, designated CS100(T), was isolated from soil in Chungbuk, Korea. Phylogenetic analysis and comparative studies based on the 16S rRNA gene sequence showed that strain CS100(T) belonged to the genus Flavobacterium in the family Flavobacteriaceae. Strain CS100(T) showed the highest sequence similarities to Flavobacterium glaciei JCM 13953(T) (97.6 %) and Flavobacterium johnsoniae KACC 11410(T) (97.1 %). Sequence similarity to other members of the genus Flavobacterium was 91.5-97.0 %. Growth occurred at 4-30 °C, at pH 5.0-9.0 and in the presence of 0-2 % (w/v) NaCl. Flexirubin-type pigments were produced. Menaquinone-6 (MK-6) was the major respiratory quinone and the major fatty acids were iso-C(15 : 0) (17.3 %), summed feature 3 (comprising iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c, 15.5 %) and C(16 : 0) (11.8 %). The DNA G+C content was 36.4 mol%. Strain CS100(T) hydrolysed skimmed milk and gelatin, but not chitin or pectin, and showed oxidase and catalase activities. DNA-DNA relatedness was 3.0 % with F. glaciei JCM 13953(T) and 11.5 % with F. johnsoniae KACC 11410(T). On the basis of the evidence from this study, strain CS100(T) represents a novel species of the genus Flavobacterium, for which the name Flavobacterium chungbukense sp. nov. is proposed. The type strain is CS100(T) ( = KACC 15048(T) = JCM 17386(T)).

Roseovarius halotolerans sp. nov., isolated from deep seawater.

A Gram-reaction-negative, non-motile, aerobic bacterium, designated HJ50(T), was isolated from deep seawater of the East Sea, South Korea. Cells were ovoid to rod-shaped (0.5-0.8x1.3-3.0 mum), often with unequal ends, suggesting a budding mode of reproduction. The strain had an absolute requirement for sea salts and tolerated up to 20 % (w/v) sea salts. Propionate, dl-lactate, 2-ketogluconate, 3-hydroxybutyrate and rhamnose were used as growth substrates, but not mannitol, salicin, 4-hydroxybenzoate or acetate. The major fatty acid was summed feature 7 (C(18 : 1)omega7c/omega9t/omega12t) and the DNA G+C content was 59.0+/-0.1 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that this strain was affiliated with the genus Roseovarius. Similarities between the 16S rRNA gene sequence of strain HJ50(T) (1430 nt) and those of type strains of members of the genus Roseovarius were 94.1-96.3 %. DNA-DNA relatedness values between strain HJ50(T) and the type strains of members of the genus Roseovarius were low (1.3-24.6 %). Physiological and biochemical differences support assignment of strain HJ50(T) to the genus Roseovarius as a representative of a novel species. The name Roseovarius halotolerans sp. nov. is proposed, with HJ50(T) (=KCTC 22224(T) =LMG 24468(T)) as the type strain.

Diaphorobacter oryzae sp. nov., isolated from a thiosulfate-oxidizing enrichment culture.

A taxonomic study was performed on two isolates, strains RF3(T) and RF21, recovered from a thiosulfate-oxidizing enrichment culture. Comparative 16S rRNA gene sequence analysis showed that these isolates were clearly affiliated with the class Betaproteobacteria. Strains RF3(T) and RF21 were most closely related to Diaphorobacter nitroreducens NA10B(T) (97.9 and 98.2 % 16S rRNA gene sequence similarity, respectively). The level of 16S rRNA gene sequence similarity between strains RF3(T) and RF21 was 99.8 %. The two isolates were Gram-negative, aerobic and denitrifying. Growth was observed at 7-35 degrees C. Physiological and biochemical properties of strains RF3(T) and RF21 were different from those of D. nitroreducens NA10B(T) in that strains RF3(T) and RF21 were able to utilize l-histidine, 2-ketogluconate and caprate, but unable to utilize suberate. The G+C contents of the genomic DNA of strains RF3(T) and RF21 were 62.9 and 62.8 mol%, respectively, and the predominant quinone was ubiquinone-8. Strains RF3(T) and RF21 possessed C(16 : 0), C(17 : 0) cyclo, and C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH as major fatty acids. DNA-DNA relatedness data indicated that strains RF3(T) and RF21 represent a genomic species separate from D. nitroreducens. On the basis of the evidence presented from this polyphasic analysis, it is suggested that strains RF3(T) and RF21 represent a novel species of the genus Diaphorobacter, for which the name Diaphorobacter oryzae sp. nov. is proposed. The type strain is RF3(T) (=KCTC 22225(T)=LMG 24467(T)).

Deletion of xylR gene enhances expression of xylose isomerase in Streptomyces lividans TK24.

Glucose (xylose) isomerases from Streptomyces sp. have been used for the production of high fructose corn syrup for industrial purposes. An 11-kb DNA fragment containing the xyl gene cluster was isolated from Streptomyces lividans TK24 and its nucleotide sequences were analyzed. It was found that the xyl gene cluster contained a putative transcriptional repressor (xylR), xylulokinase (xylB), and xylose isomerase (xylA) genes. The transcriptional directions of the xylB and xylA genes were divergent, which is consistent to those found in other streptomycetes. A gene encoding XylR was located downstream of the xylB gene in the same direction, and its mutant strain produced xylose isomerase regardless of xylose in the media. The enzyme expression level in the mutant was 4.6 times higher than that in the parent strain under xylose-induced condition. Even in the absence of xylose, the mutant strain produce over 60% of enzyme compared with the xylose-induced condition. Gel mobility shift assay showed that XylR was able to bind to the putative xyl promoter, and its binding was inhibited by the addition of xylose in vitro. This result suggested that XylR acts as a repressor in the S. lividans xylose operon.

Paenibacillus donghaensis sp. nov., a xylan-degrading and nitrogen-fixing bacterium isolated from East Sea sediment.

A Gram-positive and endospore-forming strain, JH8T, was isolated from deep-sea sediment and identified as a member of the genus Paenibacillus on the basis of 16S rRNA gene sequence and phenotypic analyses. According to a phylogenetic analysis, the most closely related species was Paenibacillus wynnii LMG 22176T (96.9%). Strain JH8T was also facultatively anaerobic and grew optimally at 20-25degreesC. The major cellular fatty acid was anteiso-C15:0, and the DNA G+C content was 53.1 mol%. The DNA-DNA relatedness between the isolate and Paenibacillus wynnii LMG 22176T was 7.6%, indicating that strain JH8T and P. wynnii belong to different species. Based on the phylogenetic, phenotypic, and chemotaxonomic characteristics, strain JH8T would appear to belong to a novel species, for which the name Paenibacillus donghaensis sp. nov. is proposed (type strain =KCTC 13049T=LMG 23780T).

Planococcus donghaensis sp. nov., a starch-degrading bacterium isolated from the East Sea, South Korea.

A novel Gram-positive, aerobic bacterium, strain JH1T, was isolated from deep-sea sediment of the East Sea, South Korea, and identified by methods of polyphasic taxonomy. The strain was oxidase-positive, motile and coccus-shaped. The genomic DNA G+C content of strain JH1T was 47 mol%. The major fatty acid of strain JH1T was anteiso-C15:0 and the predominant menaquinones were MK-7 and MK-8. Similarity of the 16S rRNA gene sequence (1452 nt) of strain JH1T to those of species of the genera Planococcus and Planomicrobium was 96.0-98.2%. The signature nucleotides in the 16S rRNA gene sequence were compared with those of previously studied type strains of species in the genera Planococcus and Planomicrobium, and suggested that strain JH1T belongs to the genus Planococcus. In addition, phylogenetic analysis showed that strain JH1T was located within the cluster comprising Planococcus antarcticus and Planococcus kocurii. DNA-DNA hybridization showed that it had 9.3% genomic relatedness with Planococcus antarcticus DSM 14505T and 22.9% with Planococcus kocurii DSM 20747T. On the basis of the phenotypic, phylogenetic and genomic data, a novel species of the genus Planococcus, Planococcus donghaensis sp. nov., is proposed, with type strain JH1T (=KCTC 13050T=LMG 23779T).