Klenkia sesuvii sp. nov., isolated from leaves of halophyte Sesuvium portulacastrum.

During a study on the diversity of culturable actinobacteria from coastal halophytes in Thailand, strain LSe6-5T was isolated from leaves of sea purslane (Sesuvium portulacastrum L.), and a polyphasic approach was employed to determine its taxonomic position. The 16S rRNA gene sequences analysis indicated that the strain was most closely related to Klenkia brasiliensis Tu 6233T (99.2 %), Klenkia marina YIM M13156T (99.1 %), and Klenkia terrae PB261T (98.7 %). The genome of strain LSe6-5T was estimated to be 4.33 Mbp in size, with DNA G+C contents of 74.3%. A phylogenomic tree based on whole-genome sequences revealed that strain LSe6-5T formed a clade with Klenkia marina DSM 45722T, indicating their close relationship. However, the average nucleotide identity (ANI)-blast, ANI-MUMmer, and dDDH values between strain LSe6-5T with K. marina DSM 45722T (87.1, 88.9, and 33.0 %) were below the thresholds of 95-96 % ANI and 70 % dDDH for identifying a novel species. Furthermore, strain LSe6-5T showed morphological and chemotaxonomic characteristics of the genus Klenkia. Cells were motile, rod-shaped, and Gram-stain-positive. Optimal growth of strain LSe6-5T occurred at 28 °C, pH 7.0, and 0-3 % NaCl. The whole-cell hydrolysates contained meso-diaminopimelic acid as the diagnostic diamino acid, with galactose, glucose, mannose, and ribose as whole-cell sugars. The predominant menaquinones were MK-9(H4) and MK-9(H0). The polar lipid profile was composed of diphosphatidylglycerol, hydroxyphosphatidylethanolamine, phosphatidylinositol, glycophosphatidylinositol, an unidentified phospholipid, and an unidentified lipid. Major cellular fatty acids were iso-C15 : 0, iso-C16 : 0, and iso-C17 : 0. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, it is supported that strain LSe6-5T represents a novel species of the genus Klenkia, for which the name Klenkia sesuvii sp. nov. is proposed. The type strain is strain LSe6-5T (=TBRC 16417T= NBRC 115929T).

Kitasatospora cathayae sp. nov., a novel endophytic actinomycete isolated from the leaves of Cathaya argyrophylla.

Strain HUAS 3-15T was isolated from the leaves of Cathaya argyrophylla collected from Chenzhou, Hunan Province, PR China. The main fatty acids (>5.0 %) of the strain were anteiso-C15 : 0, C16 : 0, C18 : 1 ω9c, iso-C16 : 0, summed feature 5 (C18 : 2 ω6,9c/C18 : 0 ante), iso-C15 : 0 and anteiso-C17 : 0. MK-9(H6), MK-9(H8) and MK-9(H4) were detected as respiratory quinones. The diagnostic cell-wall diamino acid was meso-diaminopimelic acid. Galactose, glucose and ribose were also present in the cell wall. The major polar lipids consisted of diphosphatidylglycerol, phosphatidyl ethanolamine, phosphatidylinositol mannosides and unidentified phospholipids. The DNA G+C content of the genome sequence, consisting of 8 860 963 bp, is 72.4 mol%. blast analysis based on 16S rRNA gene sequences revealed that the strain belongs to the genus Kitasatospora, with 99.37, 99.03, 98.95, 98.68 and 98.67 % sequence similarity to Kitasatospora aureofaciens ATCC 10762T, Kitasatospora viridis DSM 44826T, Kitasatospora xanthocidica NBRC 13469T, Kitasatospora aburaviensis NRRL B-2218T and Kitasatospora kifunensis IFO 15206T, respectively. Phylogenetic trees based on 16S rRNA gene and whole-genome sequences demonstrated that strain HUAS 3-15T formed a well-supported cluster with K. aureofaciens ATCC 10762T. Further genomic characterization through average nucleotide identity (ANIb/m) and digital DNA-DNA hybridization analysis between strain HUAS 3-15T and K. aureofaciens ATCC 10762T showed values of 90.62/92.55 % and 45.3 %, respectively, lower than the 95-96 % ANI threshold and 70.0 % cutoff used as guideline values for species delineation in bacteria. Furthermore, the differences between the strain and its phylogenomic neighbour in terms of physiological (e.g. sole carbon source growth) and chemotaxonomic (e.g. cellular fatty composition) characteristics further supported this conclusion. Consequently, we concluded that strain HUAS 3-15T represents a novel species of the genus Kitasatospora, for which the name Kitasatospora cathayae sp. nov. is proposed. The type strain is HUAS 3-15T (=MCCC 1K08542T=JCM 36274T).

Menaquinone-4 Alleviates Neurological Deficits Associated with Intracerebral Hemorrhage by Preserving Corticospinal Tract in Mice.

Menaquinone-4 (MK-4) is an isoform of vitamin K2 that has been shown to exert various biological actions besides its functions in blood coagulation and bone metabolism. Here we examined the effect of MK-4 on a mouse model of intracerebral hemorrhage (ICH). Daily oral administration of 200 mg/kg MK-4 starting from 3 h after induction of ICH by intrastriatal collagenase injection significantly ameliorated neurological deficits. Unexpectedly, MK-4 produced no significant effects on various histopathological parameters, including the decrease of remaining neurons and the increase of infiltrating neutrophils within the hematoma, the increased accumulation of activated microglia/macrophages and astrocytes around the hematoma, as well as the injury volume and brain swelling by hematoma formation. In addition, ICH-induced increases in nitrosative/oxidative stress reflected by changes in the immunoreactivities against nitrotyrosine and heme oxygenase-1 as well as the contents of malondialdehyde and glutathione were not significantly affected by MK-4. In contrast, MK-4 alleviated axon tract injury in the internal capsule as revealed by neurofilament-H immunofluorescence. Enhanced preservation of the corticospinal tract by MK-4 was also confirmed by retrograde labeling of neurons in the primary motor cortex innervating the spinal cord. These results suggest that MK-4 produces therapeutic effect on ICH by protecting structural integrity of the corticospinal tract.

Microbacterium salsuginis sp. nov., a halotolerant actinobacterium with antimicrobial activity.

A novel Gram-staining-positive actinobacterium with antimicrobial activity, designated CFH 90308T, was isolated from the sediment of a salt lake in Yuncheng, Shanxi, south-western China. The isolate exhibited the highest 16S rRNA gene sequence similarities to Microbacterium yannicii G72T, Microbacterium hominis NBRC 15708T and Microbacterium xylanilyticum S3-ET (98.5, 98.4 and 98.2 %, respectively), and formed a separate clade with M. xylanilyticum S3-ET in phylogenetic trees. The strain grew at 15-40 ºC, pH 6.0-8.0 and could tolerate NaCl up to a concentration of 15 % (w/v). The whole genome of strain CFH 90308T consisted of 4.33 Mbp and the DNA G+C content was 69.6 mol%. The acyl type of the peptidoglycan was glycolyl and the whole-cell sugars were galactose and mannose. The cell-wall peptidoglycan mainly contained alanine, glycine and lysine. The menaquinones of strain CFH 90308T were MK-12, MK-13 and MK-11. Strain CFH 90308T contained anteiso-C15:0, anteiso-C17:0, iso-C16:0 and iso-C15:0 as the predominant fatty acids. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between CFH 90308T and the other species of the genus Microbacterium were found to be low (ANIb <81.3 %, dDDH <25.6 %). The secondary metabolite produced by strain CFH 90308T showed antibacterial activities against Bacillus subtilis, Pseudomonas syringae, Aeromonas hydrophila and methicillin-resistant Staphylococcus aureus. Based on genotypic, phenotypic and chemotaxonomic results, the isolate is considered to represent a novel species of the genus Microbacterium, for which the name Microbacterium salsuginis sp. nov. is proposed. The type strain is CFH 90308T (=DSM 105964T=KCTC 49052T).

Streptomyces albipurpureus sp. nov., a novel actinobacterium with antimicrobial activity isolated from the rhizospheric soil of Fritillaria cirrhosa D. Don.

A novel actinobacterium, designated strain CWNU-1T, was isolated from the rhizospheric soil of Fritillaria cirrhosa D. Don and examined using a polyphasic taxonomic approach. The organism developed pale blue aerial mycelia that was simply branched and terminated in open or closed coils of three or more volutions on International Streptomyces Project 3 agar. Spores were ellipsoidal to cylindrical with wrinkled surfaces. The strain showed high 16S rRNA gene sequence similarity to Streptomyces kurssanovii NBRC 13192T (98.8 %), Streptomyces xantholiticus NBRC 13354T (98.7 %) and Streptomyces peucetius JCM 9920T (98.6 %). The phylogenetic result based on 16S rRNA gene and genome sequences clearly demonstrated that strain CWNU-1T formed an independent phylogenetic lineage. On the basis of orthologous average nucleotide identity, CWNU-1T was most closely related to Streptomyces inusitatus NBRC 13601T with 79.3 % identity. The results of the digital DNA-DNA hybridization analysis also indicated low levels of relatedness with other species, as the highest value was observed with S. inusitatus NBRC 13601T (25.3 %). With reference to phenotypic characteristics, phylogenetic data, orthologous average nucleotide identity and digital DNA-DNA hybridization results, strain CWNU-1T was readily distinguished from its most closely related strains and classified as representing a novel species, for which the name Streptomyces albipurpureus sp. nov. is proposed. The type strain is CWNU-1T (=CGMCC 4.7758T=MCCC 1K07402T=JCM 35391T).

Sphingobacterium oryzagri sp. nov., isolated from rice paddy soil.

An aerobic, Gram-stain-negative and short rod-shaped bacterial strain, designated M6-31T, was isolated from rice paddy soil sampled in Miryang, Republic of Korea. Growth was observed at 4-35 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 7.0-8.0) and in the presence of 0-4 % (w/v) NaCl (optimum, 0 % w/v). Phylogenetic analysis based on 16S rRNA gene sequences grouped strain M6-31T with Sphingobacterium bambusae IBFC2009T, Sphingobacterium griseoflavum SCU-B140T and Sphingobacterium solani MLS-26-JM13-11T in the same clade, with the 16S rRNA gene sequence similarities ranging from 95.8 to 96.6 %. A genome-based phylogenetic tree reconstructed by using all publicly available Sphingobacterium genomes placed strain M6-31T with S. bambusae KACC 22910T, 'Sphingobacterium deserti' ACCC 05744T, S. griseoflavum CGMCC 1.12966T and Sphingobacterium paludis CGMCC 1.12801T. Orthologous average nucleotide identity and digital DNA-DNA hybridization values between strain M6-31T and its closely related strains were lower than 74.6 and 22.0 %, respectively. The respiratory quinone was menaquinone-7, and the major polar lipid was phosphatidylethanolamine. The major fatty acids (>10 %) were C15 : 0 iso, C17 : 0 iso 3OH and summed feature 3. The phenotypic, chemotaxonomic and genotypic data obtained in this study showed that strain M6-31T represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium oryzagri sp. nov. (type strain M6-31T=KACC 22765T=JCM 35893T) is proposed.

Streptomyces pyxinae sp. nov. and Streptomyces pyxinicus sp. nov. isolated from lichen Pyxine cocoes (Sw.) Nyl.

Two novel actinobacteria, designated as LP05-1T and LP11T, were isolated from the lichen Pyxine cocoes (Sw.) Nyl. collected in Bangkok, Thailand. Genotypic and phenotypic analyses revealed that both strains represented members of the genus Streptomyces. The 16S rRNA gene of LP05-1T showed the highest similarity to the genome of Streptomyces gelaticus (98.41 %), while the 16S rRNA gene of LP11T was most similar to that of Streptomyces cinerochromogenes (98.93 %). The major menaquinones in LP05-1T were MK-9(H8), MK-9(H6), MK-9(H4) and MK-9(H2), and in LP11T, they were MK-9(H8) and MK-9(H6). Both strains exhibited the major fatty acids iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0, with LP05-1T also possessing iso-C17 : 0. The polar lipids of LP05-1T included phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside and an unidentified lipid, while those of LP11T consisted of phosphatidylethanolamine, lyso-phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositol mannoside, an unidentified aminolipid and an unidentified glycolipid. The digital DNA-DNA hybridisation (dDDH) and average nucleotide identity (ANI) values indicated that both strains are distinct from each other with values below 70 and 95 %, respectively. dDDH, ANI by blast (ANIb) and ANI by MUMmer (ANIm) values between LP05-1T and its closely related type strains were 26.07-26.80 %, 81.24-82.01 % and 86.82-86.96 %, respectively, while those for LP11T and its closely related type strains were 30.70-31.70 %, 84.09-85.31 % and 88.02-88.39 %, respectively. The results of the taxonomic investigation, including dDDH and ANI values, indicate that LP05-1T and LP11T are novel type strains of two novel species within the genus Streptomyces. The names proposed are Streptomyces pyxinae sp. nov. for strain LP05-1T (=TBRC 15494T, =NBRC 115434T) and Streptomyces pyxinicus sp. nov. for strain LP11T (=TBRC 15493T, =NBRC 115421T).

Lutimonas zeaxanthinifaciens sp. nov., a zeaxanthin-producing marine bacterium isolated from coastal sediment.

A Gram-stain-negative, yellow-pigmented, strictly aerobic, non-flagellated, motile by gliding, rod-shaped bacterium, designated strain YSD2104T, was isolated from a coastal sediment sample collected from the southeastern part of the Yellow Sea. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain YSD2104T was closely related to three type strains, Lutimonas vermicola IMCC1616T (97.4 %), Lutimonas saemankumensis SMK-142T (96.9 %), and Lutimonas halocynthiae RSS3-C1T (96.8 %). Strain YSD2104T has a single circular chromosome of 3.54 Mbp with a DNA G+C content of 38.3 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain YSD2104T and the three type strains (L. vermicola IMCC1616 T, L. saemankumensis SMK-142T, and L. halocynthiae RSS3-C1T) were 74.0, 86.2 and 73.6 %, and 17.9, 30.3 and 17.8 %, respectively. Growth was observed at 20-30 °C (optimum, 30 °C), at pH 6.5-8.5 (optimum, pH 7.0), and with NaCl concentrations of 1.5-3.5 % (optimum, 2.5 %). The major carotenoid was zeaxanthin, and flexirubin-type pigment was not produced. The major respiratory quinone was menaquinone-6. The major fatty acids (>10 %) were iso-C15 : 0, iso-C15 : 1 G, iso-C17 : 0 3-OH, summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c), and summed feature 9 (iso-C17 : 1 ω9c and/or 10-methyl C16 : 0). The major polar lipids were phosphatidylethanolamine, one unidentified aminophospholipid, two unidentified aminolipids, and eight unidentified lipids. Conclusively, based on this polyphasic approach, we classified strain YSD2104T (=KCTC 102008T=JCM 36287T) as representing a novel species of the genus Lutimonas and proposed the name Lutimonas zeaxanthinifaciens sp. nov.

Flagellimonas halotolerans sp. nov., a novel bacterium isolated from the South China Sea.

Two Gram-stain-negative strains, designed SYSU M86414T and SYSU M84420, were isolated from marine sediment samples of the South China Sea (Sansha City, Hainan Province, PR China). These strains were aerobic and could grow at pH 6.0-8.0 (optimum, pH 7.0), 4-37 °C (optimum, 28 °C), and in the presence of 0-10 % NaCl (w/v; optimum 3 %). The predominant respiratory menaquinone of strains SYSU M86414T and SYSU M84420 was MK-6. The primary cellular polar lipid was phosphatidylethanolamine. The major cellular fatty acids (>10 %) in both strains were iso-C15 : 0, iso-C15 : 1 G, and iso-C17 : 0 3-OH. The DNA G+C content of strains SYSU M86414T and SYSU M84420 were both 42.10 mol%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that these novel strains belonged to the genus Flagellimonas and strain SYSU M86414T showed the highest 16S rRNA gene sequence similarity to Flagellimonas marinaquae JCM 11811T (98.83 %), followed by Flagellimonas aurea BC31-1-A7T (98.62 %), while strain SYSU M84420 had highest 16S rRNA gene sequence similarity to F. marinaquae JCM 11811T (98.76 %) and F. aurea BC31-1-A7T (98.55 %). Based on the results of polyphasic analyses, strains SYSU M86414T and SYSU M84420 should be considered to represent a novel species of the genus Flagellimonas, for which the name Flagellimonas halotolerans sp. nov. is proposed. The type strain of the proposed novel isolate is SYSU M86414T (=GDMCC 1.3806T=KCTC 102040T).

Desertivirga arenae gen. nov., sp. nov. and Desertivirga brevis sp. nov., isolated from desert soil, and reclassification of Pedobacter xinjiangensis as Desertivirga xinjiangensis comb. nov. and Pedobacter mongoliensis as Paradesertivirga mongoliensis gen.nov., comb. nov.

Two novel bacterial strains, designated as SYSU D00823T and SYSU D00873T, were isolated from sandy soil of the Gurbantunggut Desert in Xinjiang, north-west China. SYSU D00823T and SYSU D00873T shared 99.0 % 16S rRNA gene sequence identity, and were both most closely related to Pedobacter xinjiangensis 12157T with 96.1 % and 96.0 % similarities, respectively. Phylogenetic and phylogenomic analyses revealed that the two isolates and P. xinjiangensis 12157T formed a separate distinct cluster in a stable subclade with the nearby species Pedobacter mongoliensis 1-32T, as well as the genera Pararcticibacter and Arcticibacter. Furthermore, P. mongoliensis 1-32T formed a separate deep-branching lineage and did not form a cluster with members of the genus Pedobacter. The average nucleotide identity and digital DNA-DNA hybridization values between SYSU D00823T and SYSU D00873T and related species were well below the thresholds for species delineation (<81.0 % and <24.0 %, respectively). The genomes of SYSU D00823T and SYSU D00873T were 6.19 and 6.43 Mbp in size with 40.4 % and 40.5 % DNA G+C contents, respectively. The predominant fatty acids (>10 %) of SYSU D00823T and SYSU D00873T were iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c). Menaquinone-7 was the only respiratory quinone. The major polar lipids were phosphatidylethanolamine, glycosphingolipid, aminoglycolipid/glycolipid, aminophospholipid and three or four unidentified polar lipids. These data indicated that strains SYSU D00823T and SYSU D00873T should be assigned to two novel species of a new genus within the family Sphingobacteriaceae, for which the names Desertivirga arenae gen. nov., sp. nov. and Desertivirga brevis sp. nov. are proposed. The type strains are SYSU D00823T (=CGMCC 1.18630T=MCCC 1K04973T=KCTC 82278T) and SYSU D00873T (=CGMCC 1.18629T=MCCC 1K04974T=KCTC 82281T), respectively. Accordingly, the reclassification of P. xinjiangensis as Desertivirga xinjiangensis comb. nov., and P. mongoliensis as Paradesertivirga mongoliensis gen. nov., comb. nov. are also proposed.

Paenarthrobacter aromaticivorans sp. nov., a paraoxon-degrading bacterium isolated from red pepper cultivation soil.

A bacterial strain designated MMS21-TAE1-1T, capable of degrading paraoxon, was isolated from red pepper soil (36° 25' 26.0″ N, 126° 25' 47.0″ E) and subjected to polyphasic taxonomic characterisation. MMS21-TAE1-1T was an aerobic, non-motile and Gram-stain-positive bacterium. MMS21-TAE1-1T showed growth at 10-37 °C (optimum, 30 °C), at pH 4-10 (optimum, pH 7) and in the presence of 0-6 % NaCl (optimum, 0 %). On the basis of the results of 16S rRNA gene sequence analysis, MMS21-TAE1-1T could be assigned to the genus Paenarthrobacter and shared the highest sequence similarities with Paenarthrobacter aurescens NBRC 12136T (99.72 %), then with Paenarthrobacter nitroguajacolicus G2-1T (99.65 %) and Paenarthrobacter ilicis DSM 20138T (99.17 %). However, the results of genome-based comparison using orthologous average nucleotide identity (orthoANI) and digital DNA-DNA hybridisation indicated that MMS21-TAE1-1T could be readily distinguished from all species of the genus with validly published names. The predominant menaquinone of MMS21-TAE1-1T was MK-9(H2). The diagnostic polar lipids were diphosphatidylglycerol and phosphatidylinositol, and unidentified glycolipids were also present. The major fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C16 : 0 and iso-C15 : 0. The chemotaxonomic properties of MMS21-TAE1-1T were generally consistent with those of members of the genus Paenarthrobacter. The genome of MMS21-TAE1-1T contained genes related to degradation of aromatic compounds. It is evident from the results of this study that strain MMS21-TAE1-1T merits recognition as representing a novel species of the genus Paenarthrobacter, for which the name Paenarthrobacter aromaticivorans sp. nov. is proposed. The type strain is MMS21-TAE1-1T (=KCTC 49652T = LMG 32368T).

Phytohabitans maris sp. nov., isolated from marine sediment.

A novel actinobacterium, strain ZYX-F-186T, was isolated from marine sediment sampled on Yongxing Island, Hainan Province, PR China. Based on the results of 16S rRNA gene sequence analysis, strain ZYX-F-186T belongs to the genus Phytohabitans, with high similarity to Phytohabitans kaempferiae KK1-3T (98.3 %), Phytohabitans rumicis K11-0047T (98.1 %), Phytohabitans flavus K09-0627T (98.1 %), Phytohabitans houttuyneae K11-0057T (97.9 %), Phytohabitans suffuscus K07-0523T (97.7 %), and Phytohabitans aurantiacus RD004123T (97.7 %). Phylogenetic analysis of 16S rRNA gene sequences showed that the strain formed a single subclade in the genus Phytohabitans. The novel isolate contained meso-diaminopimelic acid, d-glutamic acid, glycine, d-alanine, and l-lysine in the cell wall. The whole-cell sugars were xylose, arabinose, ribose, and rhamnose. The predominant menaquinones were MK-9(H8), MK-9(H6), and MK-9(H4). The characteristic phospholipids were phosphatidylethanolamine, phosphatidylinositol, phosphatidylmethylethanolamine, phosphatidylglycerol, and an unknown phospholipid. The major fatty acids (>5 %) were iso-C16 : 0, anteiso-C17 : 0, and iso-C18 : 0. Genome sequencing showed a DNA G+C content of 71.9 mol%. Low average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values demonstrated that strain ZYX-F-186T could be readily distinguished from its closely related species. Based on its phylogenetic, chemotaxonomic, and physiological characteristics, strain ZYX-F-186T represents a novel species of the genus Phytohabitans, for which the name Phytohabitans maris sp. nov. is proposed. The type strain is ZYX-F-186T (=CGMCC 4.8025T=CCTCC AA 2023025T=JCM 36507T).

Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov., two novel actinobacteria isolated from mangrove sediments and leaves of halophyte Sesuvium portulacastrum in Thailand.

A polyphasic approach was used to characterize two novel actinobacterial strains, designated PKS22-38T and LSe1-13T, which were isolated from mangrove soils and leaves of halophyte Sesuvium portulacastrum (L.), respectively. Phylogenetic analyses based on 16S rRNA gene sequences showed that they belonged to the genus Gordonia and were most closely related to three validly published species with similarities ranging from 98.6 to 98.1 %. The genomic DNA G+C contents of strains PKS22-38T and LSe1-13T were 67.3 and 67.2 mol%, respectively. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 93.3 and 54.9 %, respectively, revealing that they are independent species. Meanwhile, the ANI and dDDH values between the two novel strains and closely related type strains were below 80.5 and 24.0 %, respectively. Strains PKS22-38T and LSe1-13T contained C16 : 0, C18 : 1 ω9c and C18 : 0 10-methyl (TBSA) as the major fatty acids and diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol as the main phospholipids. The predominant menaquinone was MK-9(H2). Based on phenotypic, chemotaxonomic, phylogenetic and genomic data, strains PKS22-38T and LSe1-13T are considered to represent two novel species within the genus Gordonia, for which the names Gordonia prachuapensis sp. nov. and Gordonia sesuvii sp. nov. are proposed, with strain PKS22-38T (=TBRC 17540T=NBRC 116256T) and strain LSe1-13T (=TBRC 17706T=NBRC 116396T) as the type strains, respectively.

Natronosalvus hydrolyticus sp. nov., a beta-1,3-glucan utilizing natronoarchaeon from hypersaline soda lakes.

Use of curldlan, an insoluble ß-1,3-glucan, as an enrichment substrate under aerobic conditions resulted in the selection from hypersaline soda lakes of a single natronarchaeon, strain AArc-curdl1. This organism is an obligately aerobic saccharolytic, possessing a poorly explored (in Archaea) potential to utilize beta-1-3 glucans, being only a second example of a haloarchaeon with this ability known in pure culture. The main phenotypic property of the isolate is the ability to grow with insoluble ß-1,3-backboned glucans, i.e. curdlan and pachyman. Furthermore, the strain utilized starch family α-glucans, beta-fructan inulin and a limited spectrum of sugars. The major ether-bound membrane polar phospholipids included PGP-Me and PG. The glyco- and sulfolipids were absent. The major respiratory menaquinone is MK-8:8. According to phylogenomic analysis, AArc-curdl1 represents a separate species in the recently described genus Natronosalvus within the family Natrialbaceae. The closest related species is Natronosalvus amylolyticus (ANI, AAI and DDH values of 90.2, 91.6 and 44 %, respectively). On the basis of its unique physiological properties and phylogenomic distance, strain AArc-curdl1T is classified as a novel species Natronosalvus hydrolyticus sp. nov. (=JCM 34865 = UQM 41566).

Vitamin K2 ameliorates osteoarthritis by suppressing ferroptosis and extracellular matrix degradation through activation GPX4's dual functions.

Vitamin K2 (VK2) is an effective compound for anti-ferroptosis and anti-osteoporosis, and Semen sojae praeparatum (Dandouchi in Chinese) is the main source of VK2. Chondrocyte ferroptosis and extracellular matrix (ECM) degradation playing a role in the pathogenesis of osteoarthritis (OA). Glutathione peroxidase 4 (GPX4) is the intersection of two mechanisms in regulating OA progression. But no studies have elucidated the therapeutic effects and mechanisms of VK2 on OA. This study utilized an in vivo rat OA model created via anterior cruciate ligament transection (ACLT) and an in vitro chondrocyte oxidative damage model induced by TBHP to investigate the protective effects and mechanisms of action of VK2 in OA. Knee joint pain in mice was evaluated using the Von Frey test. Micro-CT and Safranin O-Fast Green staining were employed to observe the extent of damage to the tibial cartilage and subchondral bone, while immunohistochemistry and PCR were used to examine GPX4 levels in joint cartilage. The effects of VK2 on rat chondrocyte viability were assessed using CCK-8 and flow cytometry assays, and chondrocyte morphology was observed with toluidine blue and alcian blue staining. The impact of VK2 on intracellular ferroptosis-related markers was observed using fluorescent staining and flow cytometry. Protein expression changes were detected by immunofluorescence and Western blot analysis. Furthermore, specific protein inhibitors were applied to confirm the dual-regulatory effects of VK2 on GPX4. VK2 can increase bone mass and cartilage thickness in the subchondral bone of the tibia, and reduce pain and the OARSI score induced by OA. Immunohistochemistry results indicate that VK2 exerts its anti-OA effects by regulating GPX4 to delay ECM degradation. VK2 can inhibit the activation of the MAPK/NFκB signaling pathway caused by reduced expression of intracellular GPX4, thereby decreasing ECM degradation. Additionally, VK2 can reverse the inhibitory effect of RSL3 on GPX4, increase intracellular GSH content and the GSH/GSSG ratio, reduce MDA content, and rescue chondrocyte ferroptosis. The protective mechanism of VK2 may involve its dual-target regulation of GPX4, reducing chondrocyte ferroptosis and inhibiting the MAPK/NFκB signaling pathway to decelerate the degradation of the chondrocyte extracellular matrix.

Menaquinone-4 alleviates hypoxic-ischemic brain damage in neonatal rats by reducing mitochondrial dysfunction via Sirt1-PGC-1α-TFAM signaling pathway.

BACKGROUND: Hypoxic-ischemic encephalopathy (HIE) is a major contributor to neonatal mortality and neurodevelopmental disorders, but currently there is no effective therapy drug for HIE. Mitochondrial dysfunction plays a pivotal role in hypoxic-ischemic brain damage(HIBD). Menaquinone-4 (MK-4), a subtype of vitamin K2 prevalent in the brain, has been shown to enhance mitochondrial function and exhibit protective effects against ischemia-reperfusion injury. However, the impact and underlying molecular mechanism of MK-4 in HIE have not been fully elucidated. METHODS: In this study, we established the neonatal rats HIBD model in vivo and oxygen-glucose deprivation and reperfusion (OGD/R) of primary neurons in vitro to explore the neuroprotective effects of MK-4 on HI damage, and illuminate the potential mechanism. RESULTS: Our findings revealed that MK-4 ameliorated mitochondrial dysfunction, reduced oxidative stress, and prevented HI-induced neuronal apoptosis by activating the Sirt1-PGC-1α-TFAM signaling pathway through Sirt1 mediation. Importantly, these protective effects were partially reversed by EX-527, a Sirt1 inhibitor. CONCLUSION: Our study elucidated the potential therapeutic mechanism of MK-4 in neonatal HIE, suggesting its viability as an agent for enhancing recovery from HI-induced cerebral damage in newborns. Further exploration into MK-4 could lead to novel interventions for HIE therapy.

Flavobacterium acetivorans sp. nov. and Flavobacterium galactosidilyticum sp. nov., psychrotolerant flavobacteria isolated from cultivated fish.

Two yellow-coloured strains, F-29T and F-340T, were isolated from fish farms in Antalya and Mugla in 2015 and 2017 during surveillance studies. The 16S rRNA gene sequence analysis showed that both strains belong to the genus Flavobacterium. A polyphasic approach involving a comprehensive genome analysis was employed to ascertain the taxonomic provenance of the strains. The overall genome-relatedness indices of digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) between the strains and the other members of the genus Flavobacterium were found to be well below the established thresholds of 70 and 95 %, respectively. The whole-genome-based phylogenetic analysis revealed that strain F-29T is closely related to Flavobacterium granuli (dDDH 39.3 % and ANI 89.4 %), while strain F-340T has a close relationship with the type strain of Flavobacterium pygoscelis (dDDH 25.6 % and ANI 81.5 %). Both strains were psychrotolerant with an optimum growth temperature of 25 °C. The chemotaxonomic characteristics of the strains were typical of the genus Flavobacterium. Both strains had phosphatidylethanolamine, aminolipids and unidentified lipids in their polar lipid profile and MK-6 as the isoprenoid quinone. The major fatty acids were iso-C15 : 0 and anteiso-C15 : 0. The genome size of the strains was 3.5 Mb, while G+C contents were 35.3 mol% for strain F-29T and 33.4 mol% for strain F-340T. Overall, the characterizations confirmed that both strains are representatives of two novel species within the genus Flavobacterium, for which the names Flavobacterium acetivorans sp. nov. and Flavobacterium galactosidilyticum sp. nov. are proposed, with F-29T (JCM 34193T=KCTC 82253T) and F-340T (JCM 34203T=KCTC 82263T) as the type strains, respectively.

Coraliomargarita algicola sp. nov., isolated from a marine green alga.

A Gram-stain-negative, facultative aerobic, catalase- and oxidase-positive, non-motile, non-flagellated, and coccus-shaped bacterium, strain J2-16T, isolated from a marine green alga, was characterized taxonomically. Strain J2-16T grew at 20-40 °C (optimum, 30 °C), pH 6.0-10.0 (optimum, pH 7.0), and 1.0-4.0 % (w/v) NaCl (optimum, 3.0 %). Menaquinone-7 was identified as the sole respiratory quinone, and major fatty acids (>5 %) were C18 : 1 ω9c, iso-C14 : 0, C14 : 0, anteiso-C15 : 0, C18 : 0, C16 : 0, and C17 : 1 ω8c. The polar lipids of strain J2-16T consisted of phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, and three unidentified lipids. The genome size of strain J2-16T was 5384 kb with a G+C content of 52.0 mol%. Phylogenetic analyses based on 16S rRNA gene and 120 protein marker sequences revealed that strain J2-16T formed a distinct phyletic lineage within the genus Coraliomargarita, closely related to Coraliomargarita sinensis WN38T and Coraliomargarita akajimensis DSM 45221T with 16S rRNA gene sequence similarities of 95.7 and 94.4 %, respectively. Average nucleotide identity and digital DNA-DNA hybridization values between strain J2-16T and Coraliomargarita species were lower than 71.2 and 20.0 %, respectively. The phenotypic, chemotaxonomic, and molecular features support that strain J2-16T represents a novel species of the genus Coraliomargarita, for which the name Coraliomargarita algicola sp. nov. is proposed. The type strain is J2-16T (=KACC 22590T=JCM 35407T).

Sinomonas terricola sp. nov., a plant-beneficial bacterium isolated from litchi rhizosphere soil in Guangdong, China.

A novel plant-beneficial bacterium strain, designated as JGH33T, which inhibited Peronophythora litchii sporangia germination, was isolated on Reasoner's 2A medium from a litchi rhizosphere soil sample collected in Gaozhou City, Guangdong Province, PR China. Cells of strain JGH33T were Gram-stain-positive, aerobic, non-motile, bent rods. The strain grew optimally at 30-37 °C and pH 6.0-8.0. Sequence similarity analysis based on 16S rRNA genes indicated that strain JGH33T exhibited highest sequence similarity to Sinomonas albida LC13T (99.2 %). The genomic DNA G+C content of the isolate was 69.1 mol%. The genome of JGH33T was 4.7 Mbp in size with the average nucleotide identity value of 83.45 % to the most related reference strains, which is lower than the species delineation threshold of 95 %. The digital DNA-DNA hybridization of the isolate resulted in a relatedness value of 24.9 % with its closest neighbour. The predominant respiratory quinone of JGH33T was MK-9(H2). The major fatty acids were C15 : 0 anteiso (43.4 %), C16 : 0 iso (19.1 %) and C17 : 0 anteiso (19.3 %), and the featured component was C18 : 3 ω6c (1.01 %). The polar lipid composition of strain JGH33T included diphosphatidylglycerol, phosphatidylglycerol, dimannosylglyceride, phosphatidylinositol and glycolipids. On the basis of polyphasic taxonomy analyses data, strain JGH33T represents a novel species of the genus Sinomonas, for which the name Sinomonas terricola sp. nov. is proposed, with JGH33T (=JCM 35868T=GDMCC 1.3730T) as the type strain.

Shewanella phaeophyticola sp. nov. and Vibrio algarum sp. nov., isolated from marine brown algae.

Two Gram-stain-negative, rod-shaped bacteria, designated as strains KJ10-1T and KJ40-1T, were isolated from marine brown algae. Both strains were catalase-positive, oxidase-positive, and facultative aerobic. Strain KJ10-1T exhibited optimal growth at 25 °C, pH 7.0, and 3 % NaCl, whereas strain KJ40-1T showed optimal growth at 25 °C, pH 7.0, and 2 % NaCl. The respiratory quinones of strain KJ10-1T were ubiquinone-8, ubiquinone-7, menaquinone-7, and methylated menaquinone-7, while the respiratory quinone of strain KJ40-1T was only ubiquinone-8. As major fatty acids, strain KJ10-1T contained C16 : 0, C17 : 1 ω8c, iso-C15 : 0, and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c) and strain KJ40-1T contained C16 : 0 and summed features 3 and 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The major polar lipids in strain KJ10-1T were phosphatidylethanolamine, phosphatidylglycerol, and an unidentified aminolipid, whereas those in strain KJ40-1T were phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The DNA G+C contents of strains KJ10-1T and KJ40-1T were 42.1 and 40.8 mol%, respectively. Based on 16S rRNA gene sequences, strains KJ10-1T and KJ40-1T exhibited the closest relatedness to Shewanella saliphila MMS16-UL250T (98.6 %) and Vibrio rumoiensis S-1T (95.4 %), respectively. Phylogenetic analyses, based on both 16S rRNA and 92 housekeeping genes, showed that the strains formed distinct phylogenic lineages within the genera Shewanella and Vibrio. Digital DNA-DNA hybridization and orthologous average nucleotide identity values between strain KJ10-1T and other Shewanella species, as well as between strain KJ40-1T and other Vibrio species, were below the thresholds commonly accepted for prokaryotic species delineation. Based on the phenotypic, chemotaxonomic, and phylogenetic data, strains KJ10-1T and KJ40-1T represent novel species of the genera Shewanella and Vibrio, respectively, for which the names Shewanella phaeophyticola sp. nov. and Vibrio algarum sp. nov. are proposed, respectively. The type strains of S. phaeophyticola and V. algarum are KJ10-1T (=KACC 22589T=JCM 35409T) and KJ40-1T (=KACC 22588T=JCM 35410T), respectively.