Thermus thermamylovorans sp. nov., isolated from a hot spring.

A novel thermophilic bacterium, designated CFH 72773T was isolated from the enrichment of a Jinze hot spring sample which was collected from Dientan town, Tengchong county, Yunnan province, south-western PR China. Cells were Gram-stain-negative, aerobic, non-motile, rod-shaped and non-sporulating. The taxonomic position of the strain was investigated by using a polyphasic approach. Growth occurred at 37-75 °C, pH 6.0-8.0 and with 0-2.0 % (w/v) NaCl. Comparison of the 16S rRNA gene sequences indicated the strain represented a member of the genus Thermus and showed close relationships to the type strains Thermus caliditerrae YIM 77925T (96.3 % similarity) and Thermus igniterrae RF-4T (96.2 % similarity). The whole genome of CFH 72773T consisted of 2.25 Mbp and the DNA G+C content was 69.5 mol%. A total of 2262 genes, including a variety of enzymes for chemolithotrophy and anerobic respiration, were predicted. The strain had a unique negative oxidase activity and could hydrolyze starch at high temperature. Furthermore, various genes related to methane, sulfur, fumarate and nitrate metabolism were found, all these indicated that it is worth studying the novel strain. The predominant menaquinone is MK-8. The predominant cellular fatty acids included iso-C15 : 0, iso-C16 : 0 and iso-C17 : 0. The major polar lipids were comprised of aminophospholipid, glycolipid and two phospholipids. On the basis of low ANI values, different phenotypic and chemotaxonomic characters and phylogenetic analysis, we made a proposal that strain CFH 72773T represents a novel member of the genus Thermus, for which the name Thermus thermamylovorans sp. nov. is proposed. The type strain is CFH 72773T (=CCTCC AB2018244T=KCTC 43129T).

Paracoccus luteus sp. nov., isolated from the intestine of grass carp.

A novel Gram-negative bacterium, designated CFH 10530T, was isolated from the intestine of grass carp. The sample was collected from the aquaculture training base at the College of Fisheries, Henan Normal University, Xinxiang, PR China. Cells of strain CFH 10530T were coccoid, ovoid or short-rod-shaped, aerobic, non-spore-forming and non-motile. 16S rRNA gene sequence analysis demonstrated that strain CFH 10530T was closely related to Paracoccus endophyticus SYSUP0003T (97.7 % sequence similarity), Paracoccus halophilus HN-182T (96.5 %) and Paracoccus panacisoli DCY94T (96.1 %). The strain grew optimally at 25-28 °C, at pH 7.0 and with 0-2 % (w/v) NaCl. Cells were positive for catalase and oxidase, nitrate was reduced and H2S was not produced. The isoprenoid quinone was Q-10. Major cellular fatty acids were summed feature 8, C18 : 0 and C18 : 03-OH. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, one unidentified aminolipid and five unidentified polar lipids. The genome size was 3 331 229 bp with a G+C content of 69.6 mol%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between CFH 10530T and the other species of the genus Paracoccus were found to be below the recommended levels for species delineation (ANIm <85, ANIb <80 and dDDH <24 %). Based on its physiological properties, chemotaxonomic characteristics and low ANI and dDDH results, strain CFH 10530T is considered to represent a novel species for which the name Paracoccus luteus sp. nov., is proposed. The type strain is CFH 10530T (=KCTC 62919T=CGMCC 1.16597T).

Azospirillum thermophilum sp. nov., isolated from a hot spring.

A novel Gram-staining negative, aerobic, motile by flagellum, rod-shaped bacterium, designated CFH 70021T was isolated from a hot spring soil sample collected from Tengchong, Yunnan province, PR China. Growth of CFH 70021T occurred at 15-50 °C (optimum 50 °C), pH 5.0-7.0 (optimum pH 7.0) and with 0-3.0 % (w/v) NaCl (optimum 0 %, w/v). The genome of CFH 70021T consisted of four complete circular chromosomes and five plasmids, the genomic DNA G+C content was 69.3 mol%. Comparison of the 16S rRNA gene sequences indicated that CFH 70021T represented a member of the genus Azospirillum and showed close relationship with the type strains of Azospirillum agricola CC-HIH038T (97.8 %), Azospirillum rugosum IMMIB AFH-6T (97.6 %), Azospirillum doebereinerae GSF71T (97.6 %), Azospirillum thiophilum DSM 21654T (97.4 %) and Azospirillum picis IMMIB TAR-3T (97.2 %). The polar lipids of CFH 70021T contained diphosphatidylglycerol, phosphatidylmehtylethanolamine, phosphatidylglycerol, phosphatidylcholine, two aminolipids and an unidentified phospholipid. The predominant cellular fatty acids (>10 %) included C19:0cyclo ω8c (11.4 %), C16 : 0 (27.6 %) and summed feature 8 (C18:1ω7c/C18:1ω6c, 40.9 %). The major isoprenoid quinone was Q-10. On the basis of the low ANIb result (<78 %) and different phenotypic and chemotaxonomic characters, we conclude that strain CFH 70021T represents a novel member of the genus Azospirillum, for which the name Azospirillum thermophilum sp. nov. is proposed. The type strain is CFH 70021T (=KCTC 62259T= CCTCC AB2018121T).

Effects of dietary Radix Rehmanniae Preparata polysaccharides on the growth performance, immune response and disease resistance of Luciobarbus capito.

This work explores the effects of dietary Radix Rehmanniae Preparata polysaccharide (RRPP) supplementation on the growth performance, nonspecific immune responses, immune- and growth-related gene expression and disease resistance to Aeromonas hydrophila in Luciobarbus capito. Diets containing five concentrations of 0%, 0.05%, 0.1%, 0.2% and 0.4% RRPP were fed to fish for 60 d. The results indicated that the growth performance significantly increased in the 0.1%, 0.2% and 0.4% RRPP groups compared with that in the control (P < 0.05). The activities of serum lysozyme (LAZ), acid phosphatase (ACP), superoxide dismutase (SOD), alkaline phosphatase (AKP) and total protein (TP) were significantly increased in the appropriate RRPP supplemented groups (P < 0.05). With respect to immune- and growth-related genes, such as interleukin (IL)-1ß, IL-8, tumor-necrosis factor (TNF)-α, interferon (IFN)-γ, growth hormone (GH), insulin-like growth factor (IGF)-I and IGF-II, up-regulation were observed in the three organs (kidney, spleen, gut) of the fish fed with RRPP, compared with the control. In contrast, the mRNA expression of IL-10 and transforming-growth factor (TGF)-ß were downregulated. After challenge with A. hydrophila, the final survival rate was significantly higher in fish fed the RRPP supplement than that in the control group (P < 0.05). In conclusion, RRPP enhanced the growth performance, immune response and disease resistance of Luciobarbus capito, with the greatest effects at 0.2% RRPP.

Dynamics of a microbial community during ensiling and upon aerobic exposure in lactic acid bacteria inoculation-treated and untreated barley silages.

This study investigated the effects of lactic acid bacteria on bacterial and fungal community during the fermentation process and aerobic exposure phase of barley ensiled with preparation of lactic acid bacteria (LAB). The inoculated silages displayed higher contents of lactic acid, acetic acid, and propionic acid as well as a greater number of lactic acid bacteria during ensiling. LAB-treated silage decreased the bacterial diversity during both ensiling and aerobic exposure but increased the fungal diversity during ensiling of barley. LAB-treated silage during ensiling increased the abundance of Lactobacillus but decreased that of Weissella. After aerobic exposure, LAB-treated silage increased the abundance of Lactobacillus but decreased that of Acinetobacter. Acinetobacter, Enterococcus, Providencia, and Empedobacter were the dominant bacteria after aerobic exposure. In conclusion, LAB-treated silage enhanced the number of desirable Lactobacillus and inhibited the growth of undesirable microorganisms, such as Acinetobacter.