Κυριακή, 14 Απριλίου 2019

Antonie van Leeuwenhoek

Phoenicibacter congonensis gen. nov., sp. nov., a new genus isolated from the human gut and its description using a taxonogenomic approach

Abstract

Culturomics has recently allowed the isolation and description of previously uncultured bacteria from the human microbiome at different body sites. As part of a project aiming to describe the human gut microbiota by culturomics, Phoenicibacter congonensis strain Marseille-P3241T was isolated from the gut of a 45 years old Pygmy female. In the present work, we aim to describe this strain via the taxonogenomics approach. The major phenotypic, genomic and biochemical characteristics of this strain were analysed. Strain Marseille-P3241T is an anaerobic, Gram-positive and motile coccobacillus that grows optimally at 37 °C. The genome of strain Marseille-P3241T is 1,447,956 bp long with 43.44% GC content and its 16S rRNA gene sequence exhibited 89% sequence similarity with that of Denitrobacterium detoxificans strain NPOH1T, the phylogenetically closest related species with current standing in nomenclature. After performing a phylogenetic and genomic analysis, we conclude that strain Marseille-P3241T (= CCUG 70681T = CSUR P3241T) represents the type species of a new genus, for which we propose the name Phoenicibacter congonensis gen. nov., sp. nov.



Calcite formation induced by Ensifer adhaerens , Microbacterium testaceum , Paeniglutamicibacter kerguelensis , Pseudomonas protegens and Rheinheimera texasensis

Abstract

A wide range of bacterial species are able to induce calcium carbonate precipitation. Using our own laboratory-preserved strains, we have newly discovered that Ensifer sp. MY11e, Microbacterium sp. TMd9a1, Paeniglutamicibacter sp. MSa1a, Pseudomonas sp. GTc3, and Rheinheimera sp. ATWe6 can induce the formation of calcite crystals on an agar medium. Type strains of their closely related species (Ensifer adhaerensMicrobacterium testaceumPaeniglutamicibacter kerguelensisPseudomonas protegens, and Rheinheimera texasensis) could also induce calcite formation. Although the initial pH value of the agar medium was 6.1, the pH of the agar media containing calcite, induced by cultivation of the 10 bacterial strains, increased to 8.0–8.4. The ammonification (oxidative deamination) of amino acids may been responsible for this increase in pH. The crystals formed both on and around the bacterial colonies. Furthermore, when these strains (excepting two Microbacterium strains) were cultivated on a cellulose acetate membrane filter (0.20 μm pore size) resting on the surface of the agar medium (i.e., in the membrane filter culture method), the crystals formed on the agar medium separate from the bacterial cells. These results indicate that the bacterial cells did not necessarily become nucleation sites for these crystals. We also investigated whether the studied strains could be applied to the biocementation of sand, and found that only two Ensifer strains were able to form large sand lumps.



Edaphocola aurantiacus gen. nov., sp. nov., a new member of the family Chitinophagaceae isolated from wetland soil in South Korea

Abstract

A short rod-shaped, yellow–orange pigmented, strictly aerobic bacterium, designated as strain H2T, was isolated from the wetland soil of Halla Mountain, Jeju-island, South Korea. Growth was observed at temperatures of 10–30 °C (optimum at 25–30 °C), pH of 6–8 (optimum at pH 7), and salt concentrations of 0–1% (w/v) NaCl (optimum at 0%). The strain H2T was found to be a catalase and oxidase-positive, non-motile, Gram-negative bacterium. On the basis of 16S rRNA gene sequence similarity and phylogenetic analysis, strain H2T was found to be related to the members of the Chitinophagaceae family, being closely related to Taibaiella chishuiensisAY17T (94.3% sequence similarity). The major polar lipids are phosphatidylethanolamine and glycolipid. Strain H2T contained MK-7 as the only menaquinone as well as iso-C15:0, iso-C15:1 G and iso-C17:0 3-OH as the major fatty acids (> 15%). The DNA G+C content of strain H2T was determined to be 48.3 mol%. Based on the phylogenetic, phenotypic characteristics and chemotaxonomic analysis data, strain H2T (= KCTC 62115T = JCM 32353T) should be classified as representative of a novel species of a novel genus within the family Chitinophagaceae, for which the name Edaphocola aurantiacus gen. nov., sp. nov., is proposed.



Studies in the Stypella vermiformis group (Auriculariales, Basidiomycota)

Abstract

Stypella vermiformis is a heterobasidiomycete producing minute gelatinous basidiocarps on rotten wood of conifers in the Northern Hemisphere. In the current literature, Stypella papillata, the genus type of Stypella(described from Brazil), is treated as a taxonomic synonym of S. vermiformis. In the present paper, we revise the type material of S. papillata and a number of specimens addressed to S. vermiformis. As a result, the presumed synonymy of S. papillata and S. vermiformis is rejected and the genus Stypella is restricted to the single species S. papillata. Morphological and molecular phylogenetic studies of specimens from the Northern Hemisphere corresponding to the current concept of S. vermiformis uncovered three species from two newly described genera. S. vermiformis s.str. is distributed in temperate Europe and has small-sized basidia and basidiospores, and it is placed in a new genus, Mycostilla. Another genus, Stypellopsis, is created for two other species, the North American Stypellopsis farlowii, comb. nov., and the North European Stypellopsis hyperborea, sp. nov. Basidia and basidiospores of Stypellopsis spp. are larger than in Mycostilla vermiformis but other morphological characters are very similar. In addition, Spiculogloea minuta (Spiculogloeomycetes, Pucciniomycotina) is reported as new to Norway, parasitising basidiocarps of M. vermiformis and Tulasnella spp.



Winogradskyella algae sp. nov., a marine bacterium isolated from the brown alga

Abstract

An aerobic, Gram-negative, yellow-pigmented non-motile rod-shaped bacterium Kr9-9T was isolated from a brown alga specimen collected near the Kuril Islands. Based on the 16S rRNA gene sequence analysis strain Kr9-9T was assigned to the genus Winogradskyella, and its close phylogenetic neighbors were found to be Winogradskyella damuponensis KCTC 23552TWinogradskyella sediminis LMG 28075T, and Winogradskyella rapidaCCUG 59098T showing high similarities of 98.1%, 97.5%, and 97.1%, respectively. It contained MK-6 as the predominant menaquinone and iso-C15:0, anteiso-C15:0, iso-C16:0 3-OH followed by iso-C15:1 as the major fatty acids. Polar lipids included phosphatidylethanolamine, three unidentified aminolipids and an unidentified lipid. The DNA C+C content was 32.3 mol%. Based on the phylogenetic analysis and distinctive phenotypic characteristics, strain Kr9-9T is concluded to represent a novel species of the genus Winogradskyella, for which the name Winogradskyella algae sp. nov. is proposed. The type strain of the species is strain Kr9-9T (= KMM 8180T = KACC 19709T).



Rhodococcus daqingensis sp. nov., isolated from petroleum-contaminated soil

Abstract

A novel Gram-stain positive, aerobic, non-motile bacterial strain, designated Z1T, was isolated from a sample of petroleum-contaminated soil collected in Daqing, Heilongjiang province, China and characterised with a series of taxonomic approaches. The morphological and chemotaxonomic properties of the isolate were typical of those of members of the genus Rhodococcus. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain Z1T belongs to the genus Rhodococcus and clustered with Rhodococcus maanshanensis DSM 44675T (99.2%, sequence similarity) and Rhodococcus tukisamuensis JCM 11308T (97.9%), respectively. However, the DNA–DNA hybridizations between strain Z1T and R. maanshanensis DSM 44675T and R. tukisamuensis JCM 11308T were both less than 70%. The optimal growth temperature and pH for strain Z1T were found to be at 28 °C and at pH 7.0. The peptidoglycan was found to contain meso-diaminopimelic acid; arabinose, galactose and glucose were detected as diagnostic sugars. The main polar lipids were identified as diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and an unidentified lipid; MK-8(H2) was found as the major menaquinone. The major fatty acids were identified as C16:0, 10-methyl C18:0 and C18:1ω9c. Mycolic acids were found to be present. The G + C content of the genomic DNA was determined to be 66.7 mol%. Based on a comparative analysis of phenotypic and genotypic characteristics, in combination with DNA–DNA hybridization results, strain Z1T can be distinguished from the type strains of its two close neighbours as a novel species of the genus Rhodococcus, for which the name Rhodococcus daqingensis sp. nov. is proposed. The type strain is Z1T (= CGMCC 1.13630T = DSM 107227T).



Genome sequencing of Aureobasidium pullulans P25 and overexpression of a glucose oxidase gene for hyper-production of Ca 2+ -gluconic acid

Abstract

Gluconic acid (GA) has many applications such as in the food and pharmaceutical industry. Aureobasidium pullulans P25 strain is able to produce high levels of Ca2+-GA. The genome length, GC content and the gene number of this yeast were found to be 30.97 Mb, 50.28% and 10,922, respectively. The pathways for gluconic acid biosynthesis were annotated. Glucose oxidase (Gox) sequences from different strains of A. pullulans were highly similar but were distinct from those of other fungi. The glucose oxidase had two FAD binding sites and a signal sequence. Deletion of the GOX gene resulted in a strain that showed no Gox activity and that was unable to produce Ca2+-GA. Overexpression of the GOX gene in strain P25 generated strain GA-6 that produced 200.2 ± 2.3 Ca2+-GA g/l and 2480 U/mg of Gox activity. The productivity of Ca2+-GA was 2.78 g/l/h and the yield was 1.1 g/g.



Oceanobacillus timonensis sp. nov. and Oceanobacillus senegalensis sp. nov., two new moderately halophilic, Gram-stain positive bacteria isolated from stools sample of healthy young Senegalese

Abstract

Oceanobacillus timonensis Marseille-P3532T (CSUR P3532, CCUG 70981) and Oceanobacillus senegalensis Marseille-P3587T (CSUR P3587, CCUG 70613), are the type strains of O. timonensis sp. nov. and O. senegalensis sp. nov., respectively. They are moderately halophilic, aerobic, motile and Gram-stain positive bacteria. The strains P3532T and P3587T were isolated from stools with 3.8% and 2.1% sodium chloride (NaCl) of healthy 10 year old female and male 7-year-old children, respectively and living respectively at Dielmo and N'diop two villages in Senegal (West Africa). This study aimed to describe the genome and phenotypic characteristics of O. timonensis Marseille-P3532T and O. senegalensis Marseille-P3587T. The genomes are 4,485,335 bp long for O. timonensis and 4,300,331 bp for O. senegalensis with 38.78% and 36.92% G+C content, respectively. They contain 4306 and 3979 protein-coding and 87 and 273 RNAs genes, respectively.



Serine-glyoxylate aminotranferases from methanotrophs using different C1-assimilation pathways

Abstract

The indicator enzyme of the serine pathway of assimilation of reduced C1 compounds, serine-glyoxylate aminotransferase (Sga), has been purified from three methane-oxidizing bacteria, Methylomicrobium alcaliphilum20Z, Methylosinus trichosporium OB3b and Methylococcus capsulatus Bath. The native enzymes were shown to be dimeric (80 kDa, strain 20Z), tetrameric (~ 170 kDa, strain OB3b) or trimeric (~ 120 kDa, strain Bath). Sga from the three methanotrophs catalyse the pyridoxal phosphate-dependent transfer of an amino group from serine to glyoxylate and pyruvate; the enzymes from strains 20Z and Bath also transfer an amino group from serine to α-ketoglutarate and from alanine to glyoxylate. No other significant differences between the Sga from the three methanotrophs were found. The three methanotrophic Sga have their highest catalytic efficiencies in the reaction between glyoxylate and serine, which is in agreement with their function to provide circulation of the serine assimilation pathway.The disruption of the sga gene in Mm. alcaliphilum resulted in retardation of growth rate of the mutant cells and in a prolonged lag-phase after passaging from methane to methanol. In addition, the growth of the mutant strain is accompanied by formaldehyde accumulation in the culture liquid. Hence, Sga is important in the serine cycle of type I methanotrophs and this pathway could be related to the removal of excess formaldehyde and/or energy regulation.



Phyllobacterium phragmitis sp. nov., an endophytic bacterium isolated from Phragmites australis rhizome in Kumtag Desert

Abstract

A Gram-negative rod, designated strain 1N-3T, was isolated from a rhizome of Phragmites australis grown in Kumtag Desert, China. Phylogenetic analysis showed that the strain is closely related to Phyllobacterium salinisoli LMG 30173T with 99.0% sequence similarity in the 16S rRNA gene and 92.9% in the atpD gene. Growth was observed at salinities of 0–4% (w/v), over a pH range of 5.0–10.0 (optimum 8.0) and at temperatures of 15–40 °C (optimum 30 °C). The predominant cellular fatty acids were identified as summed feature 8 (C18:1ω7c/C18:1ω6c). The G+C content of strain 1N-3T was determined to be 60.1%. Based on phenotypic, chemotaxonomic, phylogenetic properties and genomic comparison, it is concluded that strain 1N-3T represents a novel species of the genus Phyllobacterium, for which the name Phyllobacterium phragmitis sp. nov. is proposed. The type strain is 1N-3T (=KCTC 62183T =ACCC 60071T).



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