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

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.

Two facultatively aerobic strains, designated SGZ-02^T and SGZ-792^T, were isolated from plant Pennisetum sp., exhibiting the highest 16S rRNA gene sequence similarities with the type strains of Sphingomonas zeae LMG 28739^T (98.6%) and Massilia forsythiae NBRC 114511^T (98.4%), respectively. SGZ-02^T grew between 5 and 45 °C, pH 5.0–11.0 and tolerated NaCl concentrations of 0–4% (w/v), whereas SGZ-792^T thrived at 5–40 °C, pH 5.0–11.0 and NaCl tolerance to 0–3.5% (w/v). The major quinone of SGZ-02^T was ubiquinone-10, with the dominant fatty acids being C_16:0 (13.5%), Summed Feature 3 (6.3%), C_14:02-OH (5.3%) and Summed Feature 8 (66.3%). SGZ-792^T predominantly contained ubiquinone-8, with major fatty acids being C_16:0 (20.3%), Summed Feature 3 (5.0%) and Summed Feature 8 (54.7%). Average nucleotide identity and digital DNA–DNA hybridization values between two strains and their closest references strains were below the bacterial species threshold. Based on genotypic and phenotypic characteristics, strains SGZ-02^T and SGZ-792^T are proposed as novel species within the genera Sphingomonas and Massilia, respectively. The suggested names for the new species are Sphingomonas fuzhouensis sp. nov. (SGZ-02^T = GDMCC 1.4033^T = JCM 36769^T) and Massilia phyllosphaerae sp. nov. (SGZ-792^T = GDMCC 1.4211^T = JCM 36643^T), respectively.

Identification of Fusarium species associated with diseases symptoms in plants is an important step toward understanding the ecology of plant–fungus associations. In this study, four Fusarium isolates were obtained from root rot of Oryza sativa L. in Izeh (southwest of Iran) and identified based on phylogenetic analyses combined with morphology. Phylogenetic analyses based on combined translation elongation factor 1-α, calmodulin, RNA polymerase II second largest subunit, and Beta-tubulin (tub2) sequence data delimited two new species, namely F. khuzestanicum and F. oryzicola spp. nov., from previously known species of Fusarium within F. incarnatum-equiseti species complex (FIESC). Morphologically, F. khuzestanicum produces the macroconidia with distinctly notched to foot-shaped basal cells, while basal cells in the macroconidia of F. oryzicola are more extended and distinctly elongated foot shape. Furthermore, these two new species are distinguished by the size of their sporodochial phialides and macroconidia. The results of the present show that the FIESC species complex represent more cryptic species.

A Gram-stain-negative, aerobic, motile and rod-shaped bacterium, the color of the bacterial colony ranges from light yellow to yellow, designated YC-2023-2T, was isolated from sediment sample of Yuncheng salt lake. Growth occurred at 15–45℃ (optimum 37℃), pH 6.0-9.0 (optimum pH 7.0-8.0) and with 0–8.0% NaCl (w/v, optimum 2.0%). The phylogenetic analysis based on 16S rRNA gene sequences showed that strain YC-2023-2T belonged to the family Kordiimonadaceae. The closely related members were Gimibacter soli 6D33T (92.38%), Kordiimonas lipolytica M41T (91.88%), Eilatimonas milleporae DSM 25217T (91.88%) and Kordiimonas gwangyangensis JCM 12864T (91.84%). The genome of strain YC-2023-2T was 2957513 bp, and the genomic DNA G+C content was 63.91%. The main respiratory quinone was Q-10 and the major fatty acids (>10%) were iso-C15:0, C16:0, C19:0 cyclo ω8c, Summed Feature 8 (C18:1 ω6c or C18:1 ω7c) and Summed Feature 9 (iso-C17:1 ω9c or C16:0 10-methyl). The major polar lipids consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, unidentified glycolipid, unidentified lipid, and two unidentified aminolipids. Based on the phylogenetic, phenotypic and chemotaxonomic characteristics, strain YC-2023-2T is proposed to represent a novel species of a novel genus named Yunchengibacter salinarum gen. nov., sp. nov., within the family Kordiimonadaceae. The type strain is YC-2023-2T (= GDMCC 1.4502T = KCTC 8546T).

Controlling multidrug-resistant microorganisms (MRM) has a long history with the extensive and inappropriate use of antibiotics. At the cost of these drugs being scarce, new possibilities have to be explored to inhibit the growth of microorganisms. Thus, metallic compounds have shown to be promising as a viable alternative to contain pathogens resistant to conventional antimicrobials. Gallium (Ga³⁺) can be highlighted, which is an antimicrobial agent capable of disrupting the essential activities of microorganisms, such as metabolism, cellular respiration and DNA synthesis. It was observed that this occurs due to the similar properties between Ga³⁺ and iron (Fe³⁺), which is a fundamental ion for the correct functioning of bacterial activities. The mimetic effect performed by Ga³⁺ prevents iron transporters from distinguishing both ions and results in the substitution of Fe³⁺ for Ga³⁺ and in adverse metabolic disturbances in rapidly growing cells. This review focuses on analyzing the development of research involving Ga³⁺, elucidating the intracellular incorporation of the “Trojan Horse”, summarizing the mechanism of interaction between gallium and iron and comparing the most recent and broad-spectrum studies using gallium-based compounds with antimicrobial scope.

The increasing salinity and alkalinity of soils pose a global challenge, particularly in arid regions such as Tunisia, where about 50% of lands are sensitive to soil salinization. Anthropogenic activities, including the use of treated wastewater (TWW) for irrigation, exacerbate these issues. Haloalkaliphilic bacteria, adapted to TWW conditions and exhibiting plant-growth promotion (PGP) and biocontrol traits, could offer solutions. In this study, 24 haloalkaliphilic bacterial strains were isolated from rhizosphere sample of olive tree irrigated with TWW for more than 20 years. The bacterial identification using 16S rRNA gene sequencing showed that the haloalkaliphilic isolates, capable of thriving in high salinity and alkaline pH, were primarily affiliated to Bacillota (Oceanobacillus and Staphylococcus). Notably, these strains exhibited biofertilization and enzyme production under both normal and saline conditions. Traits such as phosphate solubilization, and the production of exopolysaccharide, siderophore, ammonia, and hydrogen cyanide were observed. The strains also demonstrated enzymatic activities, including protease, amylase, and esterase. Four selected haloalkaliphilic PGPR strains displayed antifungal activity against Alternaria terricola, with three showing tolerances to heavy metals and pesticides. The strain Oceanobacillus picturea M4W.A2 was selected for genome sequencing. Phylogenomic analyses indicated that the extreme environmental conditions probably influenced the development of specific adaptations in M4W.A2 strain, differentiating it from other Oceanobacillus picturae strains. The presence of the key genes associated with plant growth promotion, osmotic and oxidative stress tolerance, antibiotic and heavy metals resistance hinted the functional capabilities might help the strain M4W.A2 to thrive in TWW-irrigated soils. By demonstrating this connection, we aim to improve our understanding of genomic fitness to stressed environments. Moreover, the identification of gene duplication and horizontal gene transfer events through mobile genetic elements allow the comprehension of these adaptation dynamics. This study reveals that haloalkaliphilc bacteria from TWW-irrigated rhizosphere exhibit plant-growth promotion and biocontrol traits, with genomic adaptations enabling their survival in high salinity and alkaline conditions, offering potential solutions for soil salinization issues.

A novel gram-stain-positive, short rod, aerobic, non-motile and non-spore-forming actinobacterial strain, designated GXG1230^T was isolated from the rhizosphere soil of a coastal mangrove forest in Beihai city, Guangxi Zhuang Autonomous Region, PR China. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain GXG1230^T was affiliated with the genus Microbacterium. Additionally, it demonstrated a high degree of similarity to Microbacterium paludicola US15^T (97.9%) and Microbacterium marinilacus YM11-607^T (97.3%). Chemotaxonomic characteristics showed that the whole-cell sugars were glucose, xylose, rhamnose and galactose. Menaquinones MK-11 and MK-12 were detected as respiratory quinones. Lysine was found in the peptidoglycan hydrolysate and the polar lipids were diphosphatidylglycerol, one phospholipid and two unidentified glycolipid. The major fatty acids were anteiso-C_15:0, iso-C_16:0 and anteiso-C_17:0. The strain GXG1230^T exhibited a genomic DNA G + C content of 71.7%. Furthermore, the average nucleotide identity values of GXG1230^T with the reference strains were 75.4% and 81.9%, respectively, while the digital DNA-DNA hybridization values were 20.1% and 25.0%. Based on physiological, chemotaxonomic and phylogenetic information, strain GXG1230^T is considered to represent a novel species of the genus Microbacterium, for which the name Microbacterium rhizophilus sp.nov is proposed, with GXG1230^T (= MCCC 1K09302^T = KCTC 59252^T) as the type strain.

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.

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