Longzhan Gan

Paracoccusacridae sp. nov., isolated from the insect Acrida cinerea living in deserted cropland

A Gram-stain-negative, aerobic, rod-shaped, non-motile bacterial strain, designated SCU-M53T, was isolated from the insect Acrida cinerea. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that strain SCU-M53T belonged to the genus Paracoccus, having Paracoccus chinensisNBRC 104937T (97.04 % 16S rRNA gene sequence similarity) and Paracoccus niistensis KCTC 22789T (96.70 %) as the most closely related phylogenetic neighbours. Growth occurred at 10-40 °C (optimum 25-30 °C), pH 5.0-10.0 (optimum pH 6.5-7.5) and with 0-4 % (w/v) NaCl (optimum 0-1 % NaCl). The fatty acids of strain SCU-M53T were C18 : 1ω7c, C18 : 0, C16 : 0, C14 : 0 3-OH, C14 : 0 and C10 : 0 3-OH. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, an unknown aminolipid, two unknown phospholipids and two unknown lipids. The isoprenoid quinone was ubiquinone-10. The DNA G+C content was 60.6 mol%. Strain SCU-M53T exhibited 36.5 and 28.6 % DNA-DNA relatedness to P. chinensis NBRC 104937T and P. niistensis KCTC 22789T, respectively. According to these results, strain SCU-M53T represents a novel species of the genus Paracoccus, for which the name Paracoccus acridae sp. nov. is proposed. The type strain is SCU-M53T (=KCTC 42932T=CGMCC 1.15419T).

Biosynthesis, characterization and antimicrobial activity of silver nanoparticles by a halotolerant Bacillus endophyticus SCU-L

Abstract We have conducted a thorough study on extracellular biosynthesis of silver nanoparticles (AgNPs) by a halotolerant bacterium Bacillus endophyticus SCU-L, which was identified by 16S rRNA gene sequencing analysis. This strain was selected during an ongoing research programme aimed at finding a novel biological method for green nanosynthetic routes using the extremophiles in unexplored hypersaline habitats. The biosynthesized AgNPs were characterized and analyzed with UV–vis spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, atomic force microscopy and X-ray diffraction. Further, the AgNPs were found to be spherical in shape with an average particle size of about 5.1 nm, and it was stable in aqueous solution for three months period of storage at room temperature under dark condition. Also, the synthesized AgNPs significantly presented antimicrobial activity against Candida albicans, Escherichia coli, Salmonella typhi and Staphylococcus aureus. The above results suggested that the present work may provide a valuable reference and theoretical basis for further exploration on microbial biosynthesis of AgNPs by halotolerant bacteria.

Planococcus salinus sp. nov., a moderately halophilic bacterium isolated from a saline-alkali soil

A novel aerobic, Gram-stain-positive, motile, moderately halophilic and coccoid bacterial strain, designated LCB217T, was isolated from a saline-alkali soil in north-western China and identified using a polyphasic taxonomic approach. Growth occurred with 3-15 % (w/v) NaCl (optimum 3-5 %), at 10-45 °C (optimum 30 °C) and at pH 7.0-9.0 (optimum pH 9.0). Strain LCB217T contained MK-7 and MK-8 as the predominant menaquinones and anteiso-C15 : 0, iso-C14 : 0 and iso-C16 : 0 as the major fatty acids. The polar lipids from strain LCB217T consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, one unidentified phospholipid, one unidentified aminophospholipid and one unidentified lipid. The peptidoglycan type was A4α (l-Lys-d-Glu). Phylogenetic analysis of the 16S rRNA gene sequence showed that strain LCB217T belonged to the genus Planococcus and was closely related to the type strains Planococcus plakortidis AS/ASP6 (II)T (98.2 % similarity), Planococcus maitriensis S1T (97.7 %) and Planococcus salinarum ISL-16T (97.2 %). The G+C content of the genomic DNA was 49.4 mol%. DNA-DNA relatedness values between strain LCB217T andPlanococcusplakortidis AS/ASP6 (II)T, Planococcusmaitriensis S1T andPlanococcussalinarum ISL-16T were 29.5, 38.1 and 39.5 %, respectively. On the basis of the phenotypic, phylogenetic and genomic data, strain LCB217T represents a novel species of the genus Planococcus, for which the name Planococcus salinus sp. nov. is proposed. The type strain is LCB217T (=CGMCC 1.15685T=KCTC 33861T).

Ornithinibacillus salinisoli sp. nov., a moderately halophilic bacterium isolated from a saline-alkali soil

A taxonomic study was performed on strain LCB256T, which was isolated from a saline-alkali soil sample taken from northwestern China. Cells of strain LCB256T were Gram-stain-positive, aerobic, rod-shaped and grew at 3-17 % (w/v) NaCl (optimum 10-15 %), 10-52 °C (optimum 25-30 °C) and pH 7.0-9.0 (optimum 8.0). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain LCB256T was most closely related to the two genera of Ornithinibacillus and Oceanobacillus, showing highest sequence similarity to Oceanobacillus limi KCTC 13823T (97.8 %) and Ornithinibacillus bavariensis WSBC 24001T (97.2 %). The peptidoglycan amino acid type was found to be A4β and the major respiratory quinone was determined to be MK-7. The polar lipid profile of strain LCB256T contained diphosphatidylglycerol, phosphatidylglycerol, one unidentified phospholipid and two unidentified aminolipids. The dominant cellular fatty acids were anteiso-C15 : 0 and iso-C15 : 0. The G+C content of genomic DNA was 39.3 mol%. DNA-DNA relatedness values between strain LCB256T and Ornithinibacillus halophilus KCTC 13822T and Oceanobacillus limi KCTC 13823T were 46.2 and 34.8 %, respectively. Based on this polyphasic taxonomic study, a novel species of the genus Ornithinibacillus, Ornithinibacillussalinisoli sp. nov. is proposed. The type strain is LCB256T (=CGMCC 1.15809T=KCTC 33862T).

Halomonas saliphila sp. nov., a moderately halophilic bacterium isolated from a saline soil

A novel, Gram-stain-negative, aerobic, rod-shaped, motile and moderately halophilic bacterium, designated strain LCB169T, was isolated from a saline soil sample from Gansu Province, PR China. The cells of LCB169T grew at 10-52 °C (optimum 30 °C), at pH 6.0-10.0 (optimum pH 8.0) and in the presence of 0-17 % (w/v) NaCl (optimum 10-15 %). Phylogenetic analysis based on 16S rRNA gene sequences and concatenated 16S rRNA, gyrB and rpoD genes sequences revealed that LCB169T represented a member of the genus Halomonas in the class Gammaproteobacteria. The most closely related species were Halomonas daqingensis DQD2-30T (98.0 % 16S rRNA gene sequence similarity), Halomonas kenyensis AIR-2T (97.8 %) and Halomonas desiderata FB2T (97.5 %). DNA-DNA relatedness values between LCB169T and H. daqingensis CGMCC 1.6443T, H. desiderata DSM 9502T and H. kenyensis DSM 17331T were 33, 35 and 38 %, respectively. The polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and three unidentified phospholipids. The major fatty acids were C18 : 1ω7c, C16 : 0, C16 : 1ω7c and C12 : 0 3-OH. The genomic DNA G+C content was 66.1 mol% and the predominant respiratory quinone was Q-9. On the basis of the results of phenotypic, phylogenetic and chemotaxonomic analyses and DNA-DNA hybridization relatedness values, LCB169T is considered to represent a novel species of the genus Halomonas, for which the name Halomonas saliphila sp. nov. is proposed. The type strain is LCB169T (=CGMCC 1.15818T=KCTC 52618T).

Streptomyces geranii sp. nov., a novel endophytic actinobacterium isolated from root of Geranium carolinianum L.

A novel endophytic actinomycete, designated A301T, was isolated from the root of Geranium carolinianum Linn collected from Mount Emei in China and characterized using a polyphasic approach. Growth occurred at 10-37 °C, pH 6-11 and in the presence of 0-5 % NaCl (w/v). Strain A301T contained ll-diaminopimelic acid as the diagnostic diamino acid in the cell-wall peptidoglycan. The whole-cell hydrolysates included galactose and ribose. The predominant menaquinones were MK-9(H6) and MK-9(H8). The major cellular fatty acids were C15 : 0, C16 :  0, anteiso-C15 : 0 and iso-C16 : 0. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, two unidentified phospholipids, three unidentified lipids and two unidentified aminophospholipids. Strain A301T shared the highest 16S rRNA gene sequence similarity to Streptomyces cinereorubersubsp. fructofermentans NBRC 15396T (98.1 %) and Streptomyces turgidiscabies ATCC 700248T (98.1 %). The DNA-DNA relatedness values between strain A301T and the two above-mentioned members of the genus Streptomyces were 42.6 % and 47.2 %, respectively. The G+C content of the DNA was 70.5 mol%. On the basis of the polyphasic approach and DNA-DNA hybridization data, strain A301T represents a novel species within the genus Streptomyces, for which the name Streptomyces geranii sp. nov. is proposed. The type strain is A301T (=CGMCC 4.7422T=JCM 32177T).

Streptomyces populi sp. nov., a novel endophytic actinobacterium isolated from stem of Populus adenopoda Maxim

A novel endophytic actinobacterium strain, designated A249T, was isolated from the stem of Populus adenopoda collected at Mount Qingcheng in south-west China. Its taxonomic position was determined by using a polyphasic approach. The cultural and morphological characteristics of isolate A249T were consistent with members of the genus Streptomyces. Growth occurred at 10-37 °C, pH 6.0-12.0 and in the presence of 0-4 % (w/v) NaCl. Analysis of the 16S rRNA gene sequence and phylogenetic trees showed the closest phylogenetic relatives to strain A249T were Streptomyces shaanxiensis JCM 16925T (98.0 % 16S rRNA gene sequence similarity) and Streptomyces lanatus JCM 4332T (97.9 %). The DNA-DNA hybridization values between the strain A249T and the two reference strains ranged from 41.4 to 49.4 %. The DNA G+C content was 71.7 mol%. The range of average nucleotide identity values was 81.5-86.7 %. Chemical analysis of cellular components indicated that strain A249T contained ll-diaminopimelic acid, xylose and galactose. The predominant menaquinones were MK-9(H6) and MK-9(H8). The polar lipids were diphosphatidylglycerol, phosphatidylinositol mannosides, phosphatidylethanolamine, two unidentified lipids, one unidentified phospholipid, one unidentified aminolipid and one unidentified aminophospholipid. The major fatty acids comprised C16 : 0, iso-C14 : 0, iso-C15 : 0, iso-C16 : 0, anteiso-C15 : 0 and C16 : 1ω7c. On the basis of the phenotypic and genotypic differentiation of the three tested strains, isolate A249T is proposed to represent a novel species of the genus Streptomyces, named Streptomyces populi sp. nov. The type strain is A249T (=CGMCC 4.7417T=JCM 32175T).

Planococcus halotolerans sp. nov., isolated from a saline soil sample in China

A novel Gram-stain-positive, coccoid or short rod-shaped, moderate-orange-pigmented, halotolerant and psychrotolerant bacterium, designated strain SCU63T, was isolated from a saline soil sample in China, and characterized by a polyphasic taxonomic approach. 16S rRNA gene sequence similarity of strain SCU63T to species in the genera Planococcus and Planomicrobium ranged from 96.5 to 98.6 %. Phylogenetic trees as well as diagnostic signature nucleotides in the 16S rRNA gene sequence supported the view that this strain should be assigned to the genus Planococcus. Further, average nucleotide identity and digital DNA-DNA hybridization analyses confirmed the separate species status of strain SCU63T relative to the closely related taxa. The isolate grew at 0-40 °C (optimum, 30-35 °C), at pH 6.5-9.0 (pH 7.0-7.5) and in the presence of 0-15 % (w/v) NaCl (3 %). The principal fatty acids were anteiso-C15 : 0, C16 : 1ω7c alcohol, iso-C16 : 0 and iso-C14 : 0, and the dominant isoprenoid quinones were MK-8 and MK-7. The peptidoglycan type was determined to be A4α (l-Lys-d-Glu), and the polar lipids contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminophospholipid and one unidentified lipid. The DNA G+C content was 44.6 mol%. Based on the genotypic, phenotypic and chemotaxonomic data, strain SCU63T can be classified as a novel species in the genus Planococcus, for which the name Planococcushalotolerans sp. nov. is proposed. The type strain is SCU63T (=CGMCC 1.13628T=KCTC 43001T).

Pedobacter chitinilyticus sp. nov., a chitin-degrading bacterium isolated from wheat leaf tissue

A bacterium, designated strain CM134L-2T, was isolated from a chitin-enriched wheat leaf microbiome in Chengdu, Sichuan province, China. It was Gram-stain-negative, strictly aerobic, non-spore-forming, motile, rod-shaped, and bright yellow in colour. Strain CM134L-2T grew at 4-35 °C, at pH 6.0-9.0 and could use chitin as the only carbon resource. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain CM134L-2T was most closely related to Pedobacter nanyangensis Q-4T (97.7 %) and Pedobacter zeaxanthinifaciens TDMA-5T (97.4 %). Digital DNA-DNA hybridization (dDDH) values between strain CM134L-2T with these two type strains were 26.8  and 20.8 %, respectively, and average nucleotide identity (ANI) values were 83.2 and 76.2 %; these values are lower than the proposed and generally accepted species boundaries of 70 % for dDDH and 95-96 % for ANI, which suggests strain CM134L-2T represents a novel species. The genomic DNA G+C content of strain CM134L-2T was 39.3 mol%, menaquinone-7 was the major respiratory quinone, phosphatidylethanolamine was the major polar lipid and the major components of the cellular fatty acids were iso-C15 : 0, and C16 : 1ω7c/C16 : 1ω6c (summed feature 3); these features supported the affiliation of strain CM134L-2T to the genus Pedobacter. Overall, strain CM134L-2T belongs to the genus Pedobacter, but can be classified as a novel species, for which the name Pedobacter chitinilyticus sp. nov. is proposed. The type strain is CM134L-2T (=CGMCC 1.16520T=KCTC 62643T).