Sphingobacterium hotanense sp. nov., isolated from soil of a Populus euphratica forest, and emended descriptions of Sphingobacterium daejeonense and Sphingobacterium shayense

Metformin modifies plasma microbial-derived extracellular vesicles in polycystic ovary syndrome with insulin resistance

INTRODUCTION

This study investigated changes in plasma microbial-derived extracellular vesicles (EVs) in patients with polycystic ovary syndrome and insulin resistance (PCOS-IR) before and after metformin treatment, and aimed to identify bacterial taxa within EVs that were biologically and statistically significant for diagnosis and treatment.

METHODS

The case-control study was conducted at Xiamen Chang Gung Hospital, Hua Qiao University. Plasma samples were collected from five PCOS-IR patients of childbearing age before and after 3 months of metformin treatment, and the samples were sequenced. The diversity and taxonomic composition of different microbial communities were analyzed through full-length 16 S glycosomal RNA gene sequencing.

RESULTS

After metformin treatment, fasting plasma glucose levels and IR degree of PCOS-IR patients were significantly improved. The 16 S analysis of plasma EVs from metformin-treated patients showed higher microbial diversity. There were significant differences in EVs derived from some environmental bacteria before and after metformin treatment. Notably, Streptococcus salivarius was more abundant in the metformin-treated group, suggesting it may be a potential probiotic.

DISCUSSION

The study demonstrated changes in the microbial composition of plasma EVs before and after metformin treatment. The findings may offer new insights into the pathogenesis of PCOS-IR and provide new avenues for research.

Sphingobacterium phlebotomi sp. nov., a new member of family Sphingobacteriaceae isolated from sand fly rearing substrate

A Gram-stain-negative, rod-shaped, non-motile, non-spore-forming, aerobic bacterium, designated type strain SSI9T, was isolated from sand fly (Phlebotomus papatasi Scopoli; Diptera: Psychodidae) rearing substrate and subjected to polyphasic taxonomic analysis. Strain SSI9T contained phosphatidylethanolamine as a major polar lipid, MK-7 as the predominant quinone, and C16 : 1ω6c/C16 : 1ω7c, iso-C15 : 0, iso-C17 : 0 3-OH and C16 : 0 as the major cellular fatty acids. Phylogenetic analysis based on 16S rRNA gene sequences revealed that SSI9T represents a member of the genus Sphingobacterium, of the family Sphingobacteriaceae sharing 96.5-88.0 % sequence similarity with other species of the genus Sphingobacterium. The results of multilocus sequence analysis using the concatenated sequences of the housekeeping genes recA, rplC and groL indicated that SSI9T formed a separate branch in the genus Sphingobacterium. The genome of SSI9T is 5 197 142 bp with a DNA G+C content of 41.8 mol% and encodes 4395 predicted coding sequences, 49 tRNAs, and three complete rRNAs and two partial rRNAs. SSI9T could be distinguished from other species of the genus Sphingobacterium with validly published names by several phenotypic, chemotaxonomic and genomic characteristics. On the basis of the results of this polyphasic taxonomic analysis, the bacterial isolate represents a novel species within the genus Sphingobacterium, for which the name Sphingobacterium phlebotomi sp. nov. is proposed. The type strain is SSI9T (=ATCC TSD-210T=LMG 31664T=NRRL B-65603T).

Two Draft Genome Sequences of Sphingobacterium sp. Strains Isolated from Honey

Here, we report two annotated draft genome sequences of Sphingobacterium sp. strains isolated from honey. The genomes of strains 1.A.4 and 1.A.5 show a limited similarity to each other and to genomes of other Sphingobacterium species, indicating that these isolates may represent new species.

Sphingobacterium humi sp. nov., isolated from soil

A Gram-stain-negative, facultatively aerobic bacterium, designated strain D1^T, was isolated from soil in South Korea. Cells of strain D1^T were non-motile rods with oxidase- and catalase-positive activities. Growth was observed at 15-40 °C (optimum, 30-37 °C), at pH 5.5-9.0 (optimum, pH 7.0-8.0) and in the presence of 0.0-5.0 % (w/v) NaCl (optimum, 0.0-1.0 %). The only respiratory quinone detected was menaquinone 7 (MK-7), and iso-C15 : 0, iso-C17 : 0 3-OH and summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) were identified as the major fatty acids. Phosphatidylethanolamine was the major polar lipid, and two unidentified glycophospholipids and four unidentified lipids were also detected as minor polar lipids. Sphingolipids, a typical chemotaxonomic feature of the genus Sphingobacterium, were detected. The G+C content of the genomic DNA was 43.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain D1^T formed a phyletic lineage with Sphingobacterium hotanense XH4^T within the genus Sphingobacterium. Strain D1^T was most closely related to S. hotanense XH4^T (98.1 % 16S rRNA gene sequence similarity) and Sphingobacterium cellulitidis R-53603^T (97.2 %), and the DNA-DNA relatedness level between strain D1^T and the type strain of S. cellulitidis was 43.1±0.7 %. Based on the phenotypic, chemotaxonomic and molecular features, strain D1^T clearly represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium humi sp. nov. is proposed. The type strain is D1^T (=KACC 18595^T=JCM 31225^T).

Sphingobacterium alkalisoli sp. nov., isolated from a saline-alkaline soil

A Gram-staining-negative, non-motile, non-spore-forming bacterium designated Y3L14T was isolated from the saline-alkaline soil of a farmland, Inner Mongolia, northern China. Strain Y3L14T could grow at 10-40 °C (optimally at 30 °C), pH 6.0-10.0 (optimally at pH 8.0), and in the presence of 0-6.0 % (w/v) NaCl (optimally with 0-2.0 %). Phylogenetic analysis based on the 16S rRNA gene and DNA gyrase subunit B (gyrB) gene sequences revealed that strain Y3L14T clustered with strains belonging to the genus Sphingobacterium, sharing the highest 16S rRNA gene sequence similarity with Sphingobacterium lactis WCC 4512T (94.99 %). Its major cellular fatty acids contained iso-C15 : 0, C16 : 0, iso-C17 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). Menaquinone-7 (MK-7) was the only isoprenoid quinone. Strain Y3L14T contained phosphatidylethanolamine, sphingophospholipid, two unknown phospholipids and three unknown lipids as the major polar lipids. The genomic DNA G+C content of strain Y3L14T was 36.0 mol%. Based on the phenotypic, phylogenetic and genotypic characteristics, strain Y3L14T represents a novel species within the genus Sphingobacterium, for which Sphingobacterium alkalisoli sp. nov. is proposed; the type strain is Y3L14T (=CGMCC 1.15782T=KCTC 52379T).

Sphingobacterium chuzhouense sp. nov., isolated from farmland soil

A novel Gram-staining-negative bacterium, designated DH-5T, was isolated from a farmland soil in Chuzhou, Anhui province, China. Cells of strain DH-5T were aerobic, non-motile, non-spore-forming and rod-shaped. The organism grew at 20-37 °C, pH 6.0-9.0 and with 0-5 % NaCl (w/v). The DNA G+C content was 42.8 mol%. The major fatty acids (>5 %) were iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C17 : 0 3-OH and C16 : 0. The respiratory quinone was MK-7, and the major polar lipids were phosphatidylethanolamine and phosphoglycolipid. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DH-5T was a member of the genus Sphingobacterium and shared the highest similarity with Sphingobacterium gobiense H7T (96.0 %), followed by Sphingobacterium arenae H-12T (94.5 %). Strain DH-5T exhibited low DNA-DNA relatedness with S. gobiense H7T (35.1±1.4 %) and S. arenae H-12T (21.4±1.0 %). On the basis of phenotypic, genotypic and phylogenetic evidence, DH-5T is considered to represent a novel species of the genus Sphingobacterium, for which the name Sphingobacterium chuzhouense sp. nov. is proposed. The type strain is DH-5T (=ACCC 19856T=KCTC 42746T).

Sphingobacterium suaedae sp. nov., isolated from the rhizosphere soil of Suaeda corniculata

A Gram-stain-negative, non-motile, non-spore-forming bacterium, designated T47T, was isolated from saline soil of the Suaeda corniculata rhizosphere, located on the bank of Wuliangsuhai Lake, Inner Mongolia, northern China. Strain T47T could grow at 10–40 °C (with 30 °C the optimal temperature), pH 6.0–8.0 (optimal pH 6.0) and in the presence of 0–6.0 % (w/v) NaCl [optimal 0–1.0 % (w/v)]. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain T47T formed a stable clade with Sphingobacterium composti 4M24T, Sphingobacterium bambusae IBFC2009T, Sphingobacterium paludis S37T and Sphingobacterium wenxiniae LQY-18T, with the 16S rRNA gene sequence similarities ranging from 91.9–95.4 %. Its major cellular fatty acids contained iso-C15 : 0 (39.9 %), summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c, 23.0 %), C16 : 0 (12.8 %) and iso-C17 : 0 3-OH (9.9 %). MK7 was the major menaquinone. The G+C content of the genomic DNA was 45.5 mol%. Based on the phenotypic, phylogenetic and genotypic characteristics, strain T47T represents a novel species within the genus Sphingobacterium, for which the name Sphingobacterium suaedae sp. nov. is proposed. The type strain is T47T ( = CGMCC 1.15277T = KCTC 42662T).

Pedobacter ureilyticus sp. nov., isolated from tomato rhizosphere soil

A Gram-stain-negative, strictly aerobic, rod-shaped and pinkish-yellow bacterium, which was motile by gliding and designated strain THG-T11(T), was isolated from tomato rhizosphere soil in Gyeonggi province, Republic of Korea. Based on 16S rRNA gene sequence comparisons, strain THG-T11(T) was found to be most closely related to 'Pedobacter zeaxanthinifaciens' TDMA-5 (95.9 % sequence similarity), Pedobacter agri PB92(T) (94.9 %), Pedobacter rhizosphaerae 01-96(T) (94.6 %) and Pedobacter alluvionis NWER-II11(T) (94.5 %). The DNA G+C content was 38.4 mol%. The only isoprenoid quinone detected in strain THG-T11(T) was menaquinone-7 (MK-7). The major component in the polyamine pattern was sym-homospermidine. The major polar lipids were phosphatidylethanolamine, an unidentified phosphoglycolipid, an unidentified glycolipid, an unidentified lipid, unidentified aminophospholipids and unidentified aminolipids. The major ceramide was found to be ceramide phosphorylethanolamine. The major fatty acids were identified as iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. These data support the affiliation of strain THG-T11(T) to the genus Pedobacter. Based on phenotypic, chemotaxonomic and phylogenetic analysis, it is proposed that strain THG-T11(T) represents a novel species of the genus Pedobacter for which the name Pedobacter ureilyticus sp. nov. is proposed, with THG-T11(T) as the type strain ( = KACC 17660(T) = JCM 19461(T)).

Sphingobacterium paludis sp. nov., isolated from wetland soil

A novel Gram-stain-negative bacteria, designated S37T, was isolated from soil of the Xixi wetland, Zhejiang province, China. Cells of strain S37T were aerobic, non-motile rods. Growth occurred at 10–37 °C (optimum, 25 °C), pH 5.0–9.7 (optimum, pH 7.5) and with 0–6 % (w/v) NaCl (optimum, 0.5 %). Based on 16S rRNA gene sequence analysis, strain S37T was found to be a member of the genus Sphingobacterium and shared highest similarity with Sphingobacterium composti 4M24T (95.78 %). The major fatty acids were summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C15 : 0 and iso-C17 : 0 3-OH, and the DNA G+C content was 43.8 mol%. The predominant respiratory quinone was MK-7. Based on its phenotypic and chemotaxonomic characteristics and phylogenetic data, strain S37T represents a novel species of the genus Sphingobacterium , for which the name Sphingobacterium paludis sp. nov. (type strain S37T = CGMCC 1.12801T = NBRC 110386T) is proposed.

Sphingobacterium gobiense sp. nov., isolated from soil of the Gobi Desert

A Gram-stain-negative, short rod-shaped, non-motile, non-spore-forming bacterial strain, designated H7(T), was isolated from the Gobi desert, Xinjiang Province of China. The temperature, NaCl and pH ranges for growth were 8-40 °C (optimum 30 °C), 0-5 % (w/v) NaCl and pH 6-10 (optimum pH 7), respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain H7(T) belonged to the genus Sphingobacterium and showed highest sequence similarity (91 %) to Sphingobacterium composti DSM 18850. The genomic DNA G+C content was 44.3 mol%. MK-7 was identified as the predominant respiratory quinone. Strain H7(T) contained C16 : 1ω7c and/or C16 : 1ω6c, iso-C15 : 0 and iso-C17 : 0 3-OH as major fatty acids. These data support the affiliation of strain H7(T) to the genus Sphingobacterium while phenotypic data indicated it is a representative strain of a novel species for which the name Sphingobacterium gobiense sp. nov. is proposed. The type strain is H7(T) ( = ACCC 05757(T) = KCTC 32293(T)).

Sphingobacterium arenae sp. nov., isolated from sandy soil

A novel, Gram-stain-negative, non-motile, non-spore-forming, short rod-shaped, aerobic bacterium designated H-12(T) was isolated from a mixed sandy soil sample collected from Xinjiang, China. Strain H-12(T) grew at 20-37 °C (optimum, 30 °C), pH 7.0-11.0 (optimum, pH 8.5) on TGY medium with 0-5 % NaCl (w/v). 16S rRNA gene sequence analysis indicated that strain H-12(T) shared sequence similarities with Sphingobacterium composti DSM 18850(T) (90.0 %). Strain H-12(T) showed a low level of DNA-DNA relatedness to Sphingobacterium composti DSM 18850(T) (45.5 %). The predominant isoprenoid quinone of strain H-12(T) was MK-7 and the major polar lipid was phosphatidylethanolamine. The predominant cellular fatty acids were C16:1ω7c and/or C16 : 1ω6c, iso-C15 : 0, iso-C17 : 0 3-OH, C16 : 0, C16 : 0 3-OH and iso-C15 : 0 3-OH. DNA G+C content of strain H-12(T) was 44.15 mol%. On the basis of phenotypic, genetic and phylogenetic data, strain H-12(T) is proposed to be a representative of a novel species of the genus Sphingobacterium, for which the name Sphingobacterium arenae sp. nov. is suggested and the type strain is H-12(T) ( = ACCC 05758(T) = KCTC 32294(T)).