Antonie Van Leeuwenhoek International Journal of General and Molecular Microbiology最新文献

Mammary pathogenic Escherichia coli (MPEC) causes mastitis, which results in substantial economic losses to the dairy industry. A high percentage of Escherichia coli isolated from cows with clinical mastitis harbor adhesin genes, such as fimH. However, it is unclear whether these adhesins are important in the adhesion of MPEC to bovine mammary epithelial cells (BMECs). Therefore, we investigated the effect of adhesins (EcpD, FdeC, and FimH) in MPEC on adherence to the bovine mammary epithelium using cultured BMECs. For this purpose, we used wild-type MPEC as well as single- and double-mutants of fimH, ecpD, and fdeC, and performed adhesion assays with BMECs. First, BMECs were cultured in the presence of lactogenic hormones to induce milk component production and tight junction formation. The bacterial count of the wild-type strain that adhered to the BMECs increased in a dose-dependent manner. In deletion mutant strains, the ΔfimH strain showed lower adhesion (P < 0.05), whereas the adhesion ratio of the ΔecpD and ΔfdeC strains was not statistically different compared with that of the wild-type strain (P > 0.05). Additionally, the fimH/fdeC double-deletion mutants showed the lowest adhesion to BMECs. In conclusion, FimH is crucial in the adhesion of MPEC to BMECs. Overall, our work identifies FimH or FimH/FdeC as interesting targets for future drugs or vaccines to improve the treatment, prevention or chronicity of mastitis induced by MPEC.

An aerobic, Gram-stain negative bacterium was isolated from sediment samples of Barkol salt lake in Hami City, Xinjiang Uygur Autonomous Region, China, with the number EGI_FJ10229^T. The strain is ellipse-shaped, oxidase-negative, catalase-positive, and has white, round, smooth, opaque colonies on marine 2216 E agar plate. Growth occurs at 4.0-37.0 ℃ (optimal:30.0 ℃), pH 7.0-9.0 (optimal: pH 8.0) and NaCl concentration of 0-8.0% (optimal: 3.0%). Phylogenetic analysis based on 16S rRNA gene and genome sequences indicated that the isolated strain should be assigned to the genus Aquibaculum and was most closely related to Aquibaculum arenosum CAU 1616 ^T. Average nucleotide identity (ANI) and Average amino-acid identity (AAI) values between the type species of the genus Aquibaculum and other related type species were lower than the threshold values recommended for bacterial species. The genomic DNA G + C content of EGI_FJ10229^T was 65.41%. The major polar lipids were diphosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine, phosphatidylethanolamine and unidentified phospholipid. The major fatty acids (> 5%) were C_19:0 cyclo ω8c (42.0%) and C_18:1 ω7c (33.78%). The respiratory quinone identified was Q-10. Differential phenotypic and genotypic characteristics of this strain and species of genus Aquibaculum showed that the strain should be classified as representing a new species belonging to this genus, for which the name Aquibaculum sediminis sp. nov. is proposed. The type strain of the proposed novel species is EGI_FJ10229^T (= KCTC 8570 ^T = GDMCC 1.4598 ^T).

A Gram-staining-negative, dark pink, rod-shaped, amastigote and cellulose-degrading strain, designated H9^T, was isolated from intestinal contents of Nipponacmea schrenckii. The isolate was able to grow at 4-42 °C (optimum, 25 °C), at pH 6.5-9.0 (optimum, pH 7.0), and with 0.0-11.0% (w/v) NaCl (optimum, 3.0-5.0%). Phylogenetic analysis of the 16S rRNA gene sequence suggested that isolate H9^T belongs to the genus Roseobacter, neighboring Roseobacter insulae YSTF-M11^T, Roseobacter cerasinus AI77^T and Roseobacter ponti MM-7 ^T, and the pairwise sequence showed the highest similarity of 99.1% to Roseobacter insulae YSTF-M11^T. The major fatty acid was summed feature 8 (C_18:1ω7c and/or C_18:1ω6c; 81.08%). The predominant respiratory quinone was Q-10. The polar lipids consisted of phosphatidylcholine, phosphatidylglycerol, an unknown lipid, and a small amount of an unknown phospholipid. The genome of strain H9^T was 5,351,685 bp in length, and the DNA G + C content was 59.8%. The average amino acid identity (AAI), average nucleotide identity (ANI), and digital DNA hybridization (dDDH) values between strain H9^T and closely related strains were 63.4-76.8%, 74.7-78.8%, and 13.4-19.7%, respectively. On the basis of the phenotypic, chemical taxonomic, and phylogenetic data, it is suggested that strain H9^T should represent a novel species in the genus Roseobacter, for which the name Roseobacter weihaiensis sp. nov. is proposed. The type strain is H9^T (= KCTC 82507 ^T = MCCC 1K04354^T).

An aerobic, Gram-stain-negative, non-motile, non-spore-forming, short rod-shaped bacterial strain, designated NCCP 15609 ^T, was isolated from the blood sample of a patient in the Republic of Korea. The strain was identified as Brevundimonas diminuta using MALDI-TOF. A phylogenetic tree constructed using 16S rRNA gene sequences revealed that the isolate was of the genus Brevundimonas with 99.8% similarity to B. naejangsanensis. The strain NCCP 15609^T genome consisted of one contig with 3,063,090 bp, and had a G+C content of 67.4%. The genome contained 2,949 protein-coding sequences, 52 tRNAs, and 6 rRNAs. The DNA-DNA hybridisation between NCCP 15609^T and B. naejangsanensis yielded 92.5% and 49.5% ± 2.6%, respectively, using the average nucleotide identity (ANI) and digital DNA-DNA hybridisation (dDDH). The predominant fatty acids of strain NCCP 15609^T were summed feature 8 (C_18:1 ω7c/C_18:1 ω6c) and C_16:0. The isolate contained polar lipids and quinone, corresponding to phosphatidylglycerol, 1,2-di-O-acyl-3-O-[D-glycopyranosyl (1 → 4)-α-D-glucopyranuronosyl] glycerol, and ubiquinone-10, respectively. Based on its phylogenetic, physiological, and chemotaxonomic characteristics, we suggest that NCCP 15609^T represents a novel pathogen resource of the genus Brevundimonas and propose to name it Brevundimonas sanguinis sp. nov. The type strain is NCCP 15609^T (= DSM 116005^T).

Gram-staining-negative, aerobic, white-cream-pearly colony, coccobacilli, and non-motile bacterial strain, PAMC 29798^T was isolated from an Antarctic lichen. The strain was acidotolerant and psychrotolerant growing at pH 4.0-7.5 (optimally at pH 4.0-6.5) and 0-25 °C (optimally at 10-20 °C). The major fatty acids are Summed Feature 8, C_18:1 2OH, and C_19:0 cyclo ω8c. The major respiratory quinone was Q-10. Phylogenetic and phylogenomic analyses indicated that strain PAMC 29798^T belonged to the genus Acidisoma and 16S rRNA gene sequences of PAMC 29798^T were closely related to Acidisoma silvae (97.7% sequence similarity), Acidisoma cellulosilyticum (96.5%), Acidisoma tundrae (96.5%), and Acidisoma sibiricum (96.3%). Genomic relatedness analyses showed that strain PAMC 29798^T was clearly distinguished from type strains of the genus Acidisoma based on values of average nucleotide identity (< 75%) and the digital DNA-DNA hybridization (< 19.6%). Genome analysis revealed that the genome size of PAMC 29798^T is approximately 5.0 Mb with a G+C content of 63.4%. The complete genome comprises 5 contigs containing 4636 protein-coding genes, 46 tRNA genes, and 2 rRNA operons. The genome possesses genes for light-harvesting complexes, type-II photosynthetic reaction center, and C-P lyase to solubilize organic phosphates, while genes encoding nitrogenase iron protein involved in the nitrogen fixation were not present. Based on the results of phylogenetic, genome-based relatedness, and physiological and genomic analyses, strain PAMC 29798^T is proposed to represent a novel species of the genus Acidisoma, with the name Acidisoma cladoniae. The type strain is PAMC 29798^T (= KCTC 82159^T = JCM 35634^T).

A sulphur-oxidizing bacterium, designated strain SCUT-2^T, was isolated from freshwater sediment collected from the Pearl River in Guangzhou, PR China. This strain was an obligate chemolithoautotroph, utilizing reduced sulphur compounds (elemental sulphur, thiosulphate, tetrathionate and sulphite) as the electron donor. Growth of strain SCUT-2^T was observed at 20-40 ℃ (optimum at 30 °C), pH 5.0-9.0 (optimum at 6.0), and NaCl concentration range of 0-9 g L^-1 (optimum at 1 g L^-1). The major cellular fatty acids were C_16:0 ω7c and cyclo-C_17:0. The DNA G + C content of the complete genome sequence was 66.8 mol%. Phylogenetic analysis based on the 16S rRNA gene sequence showed that strain SCUT-2^T formed a lineage within the genus Thiobacillus, showing gene sequence identity of 98.0% with its closest relative Thiobacillus thioparus THI 115. The genome of strain SCUT-2^T contains multiple genes encoding sulphur-oxidizing enzymes that catalyse the oxidation of reduced sulphur compounds, partial genes that are necessary for denitrification, and the genes encoding cbb₃-type cytochrome c oxidase, aa₃-type cytochrome c oxidase and bd-type quinol oxidase. Facultative anaerobic growth occurs when using nitrate as the electron acceptor and thiosulphate as the electron donor. On the basis of phenotypic, chemotaxonomic, genotypic and phylogenetic analysis, strain SCUT-2^T (= GDMCC 1.4108^T = JCM 39443^T) is deemed to represent a novel Thiobacillus species, for which we propose the name Thiobacillus sedimenti sp. nov.

A novel bacterial strain, designated DW002^T, was isolated from the sea ice of Cape Evans, McMurdo Sound, Antarctica. Cells of the strain were Gram-negative, obligate anaerobic, motile, non-flagellated, and short rod-shaped. The strain DW002^T grew at 4-32 ℃ (optimum at 22-28 ℃) and thrived best at pH 7.0, NaCl concentration of 2.5% (w/v). The predominant isoprenoid quinone of strain DW002^T was menaquinone-7 (MK-7). The major fatty acids (> 10%) of DW002^T were iso-C_15:0, anteiso-C_15:0 and iso-C_17:1ω9c. The predominant polar lipids of strain DW002^T contained two phosphatidylethanolamines, one unidentified glycolipid, one unidentified aminolipid and four unidentified lipids. The DNA G + C content of the strain DW002^T was 34.8%. Strain DW002^T encoded 237 carbohydrate-active enzymes. The strain DW002^T had genes associated with dissimilatory nitrate reduction and assimilatory sulfate reduction metabolic pathways. Based on distinct physiological, chemotaxonomic, genome analysis and phylogenetic differences compared to other members of the phylogenetically related genera in the family Marinifilaceae, strain DW002^T is proposed to represent a novel genus within the family. Therefore, the name Paralabilibaculum antarcticum gen. nov., sp. nov. is proposed. The type strain is DW002^T (=KCTC 25274^T=MCCC 1K06067^T).

Proteus faecis is a gram-negative facultative anaerobic rod-shaped bacterium capable of swarming motility. It has been isolated from numerous sources such as humans, animals, and refuse and is considered potentially pathogenic towards humans. In this study, bacteria were isolated from the blowhole of a Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis; YFP) living in captivity in China. One bacterium, P. faecis porpoise, was isolated and whole genome sequencing done. Biofilm formation, motility and antimicrobial resistance were also investigated. To find putative virulence factors, the genome of P. faecis strain porpoise was compared to the genomic sequences of eight other P. faecis isolates using the Bacterial and Viral Bioinformatics Resource Center (BV-BRC) ( https://www.bv-brc.org/ ). The goal of this study was to initially characterize the pathogenicity of this bacterium isolated from a cetacean species using both pathogenomics and conventional approaches.

The kiwifruit industry typically uses commercial pollen for artificial pollination. However, during the collection of male flowers and pollen production, pollen can be easily contaminated by pathogenic bacteria that cause diseases such as canker and flower rot. Consequently, it is crucial to understand the structure of the pollen microbial community. This study employed Illumina high-throughput sequencing technology to analyze the fungal and bacterial composition in pollen samples from various regions in Shaanxi Province. Concurrently, potential pathogenic strains were isolated using traditional microbial isolation and cultivation techniques, and their molecular identification was performed through 16S rDNA sequence analysis. A tieback test was conducted on healthy branches to verify the pathogenicity of the strains. The results revealed a rich diversity of fungi and bacteria in kiwifruit pollen. At the phylum level, pollen fungi were mainly distributed in Ascomycota, and bacteria were mainly distributed in Proteobacteria and Firmicutes. The dominant fungal genera were Mycosphaerella, Aspergillus, and Cladosporium; the dominant bacterial genera were Weissella, Pantoea, Enterobacter, and Pseudomonas, respectively. Additionally, both Erwinia persicina and Pseudomonas fluorescens, isolated from pollen, exhibited high pathogenicity toward healthy kiwifruit branches. These findings contribute to a deeper understanding of the microbial diversity in commercial kiwifruit pollen used for mass pollination.

Despite the long research history on the genus Coelastrella, its species diversity and biotechnological potential have not been fully explored. For the first time, cluster analysis of morphological characteristics was done in the representatives of the said genus. The results obtained have shown that morphological similarity does not necessarily indicate a molecular genetic relationship. It the light of it, the taxonomic status of species can reliably be determined using specific DNA region, such as 18S-ITS1-5.8S-ITS2. The V4 and V9 regions of gene 18S rRNA are relatively conservative fragments which are not suitable for species identification. The ITS2 can be used as a "short barcode". Among the advanced machine methods for delimitation species, the most effective algorithm for distinguishing Coelastrella species was the Generalized Mixed Yule Coalescent (GMYC) method. This paper represented for the first time our comprehensive review of the works devoted to the analysis of the biotechnological potential of representatives of the genus Coelastrella and shows that fatty acid composition of the three main chemogroups within the studied genus differs. In the future, this may form the basis for predicting the composition of the fatty acid profile of new strains, which is important while searching for organisms with specified biotechnological properties. In conclusion, an integrative approach was employed to describe Coelastrella affinis sp. nov., a new species of the genus Coelastrella with high biotechnological potential. Also, a new description of C. thermophila var. astaxanthina comb. nov. was proposed.