Melghirimyces algeriensis gen. nov., sp. nov., a member of the family Thermoactinomycetaceae, isolated from a salt lake.

A novel filamentous bacterium, designated NariEX(T), was isolated from soil collected from Chott Melghir salt lake, which is located in the south-east of Algeria. The strain was an aerobic, halotolerant, thermotolerant, Gram-positive bacterium that was able to grow in NaCl concentrations up to 21% (w/v), at 37-60 °C and at pH 5.0-9.5. The major fatty acids were iso- and anteiso-C(15:0). The DNA G+C content was 47.3 mol%. The major menaquinone was MK-7, but MK-6 and MK-8 were also present. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine (methyl-PE). Results of molecular and phenotypic analysis led to the description of the strain as a new member of the family Thermoactinomycetaceae. The isolate was distinct from members of recognized genera of this family by morphological, biochemical and chemotaxonomic characteristics. Strain NariEX(T) showed 16S rRNA gene sequence similarities of 95.38 and 94.28% with the type strains of Desmospora activa and Kroppenstedtia eburnea, respectively, but differed from both type strains in its sugars, polar lipids and in the presence of methyl-PE. On the basis of physiological and phylogenetic data, strain NariEX(T) represents a novel species of a new genus of the family Thermoactinomycetaceae for which the name Melghirimyces algeriensis gen. nov., sp. nov. is proposed. The type strain of Melghirimyces algeriensis, the type species of the genus, is NariEX(T) (=DSM 45474(T)=CCUG 59620(T))

Melghirimyces algeriensis gen. nov., sp. nov., a member of the family Thermoactinomycetaceae, isolated from a salt lake.

A novel filamentous bacterium, designated NariEX(T), was isolated from soil collected from Chott Melghir salt lake, which is located in the south-east of Algeria. The strain was an aerobic, halotolerant, thermotolerant, Gram-positive bacterium that was able to grow in NaCl concentrations up to 21% (w/v), at 37-60 °C and at pH 5.0-9.5. The major fatty acids were iso- and anteiso-C(15:0). The DNA G+C content was 47.3 mol%. The major menaquinone was MK-7, but MK-6 and MK-8 were also present. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine (methyl-PE). Results of molecular and phenotypic analysis led to the description of the strain as a new member of the family Thermoactinomycetaceae. The isolate was distinct from members of recognized genera of this family by morphological, biochemical and chemotaxonomic characteristics. Strain NariEX(T) showed 16S rRNA gene sequence similarities of 95.38 and 94.28% with the type strains of Desmospora activa and Kroppenstedtia eburnea, respectively, but differed from both type strains in its sugars, polar lipids and in the presence of methyl-PE. On the basis of physiological and phylogenetic data, strain NariEX(T) represents a novel species of a new genus of the family Thermoactinomycetaceae for which the name Melghirimyces algeriensis gen. nov., sp. nov. is proposed. The type strain of Melghirimyces algeriensis, the type species of the genus, is NariEX(T) (=DSM 45474(T)=CCUG 59620(T))

Microbacterium invictum sp. nov., isolated from homemade compost

Strain DC-200T was isolated from homemade compost produced from kitchen refuse and characterized using a polyphasic approach. The isolate was a Gram-positive motile short rod, facultatively aerobic, catalase-positive and oxidase-negative, and was able to grow at 10–37 6C, pH 6.0–9.5 and with up to 5% of NaCl. The peptidoglycan was of the type B1 alpha and the muramic acid residues were glycolylated. The major fatty acids were anteiso-C15 : 0 and anteiso- C17 : 0. The predominant respiratory menaquinones were MK-11 and MK-12. The G+C content of the genomic DNA was 70 mol%. Based on the analysis of the 16S rRNA gene sequence, the closest phylogenetic neighbours of strain DC-200T were Microbacterium lacus A5E-52T (98.7 %) and Microbacterium aoyamense KV-492T (98.2 %). The phenetic characterization of the isolate supports its inclusion within the genus Microbacterium; however, its distinctive phenotypic features and the results from the 16S rRNA gene sequence analysis and the DNA–DNA hybridization study suggest that the isolate represents a novel species. The name Microbacterium invictum sp. nov. is proposed. The type strain is DC-200T (5DSM 19600T5LMG 24557T)

Melghirimyces thermohalophilus sp. nov., a novel thermoactinomycete isolated from an Algerian salt lake

A novel filamentous bacterium designated Nari11AT was isolated from soil collected from a salt lake named Chott Melghir located in south east of Algeria. The strain is an aerobic, halophilic, thermotolerant, Gram-positive bacterium, growing at NaCl concentrations between 5 and 20% w/v and temperature and pH ranges between 43-60 °C and 5.0-10.0, respectively. The major fatty acids were isoC15:0, anteisoC15:0 and isoC17:0. The G+C value was 53.4 mol %. LL-diaminopimelic acid was the diamino acid of the peptidoglycan. The major menaquinone was MK-7, but MK-6 and MK-8 were also present in trace amounts. The polar lipids' profile consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine and three unidentified phospholipids. Results of molecular and phenotypic analysis led to the description of the strain as a new member to the genus Melghirimyces, family Thermoactinomycetaceae. Strain Nari11AT shows a 16S rRNA gene sequence similarity of 96.7% with Melghirimyces algeriensis. On the basis of phenotypic, physiological and phylogenetical data the type strain Nari11AT (DSM 45514T =CCUG 60050T) represents a new species for which the name Melghirimyces thermohalophilus sp. nov., is proposed

Identification of a Pseudomonas aeruginosa PAO1 DNA methyltransferase, its Targets, and physiological roles

DNA methylation is widespread among prokaryotes, and most DNA methylation reactions are catalyzed by adenine DNA methyltransferases, which are part of restriction-modification (R-M) systems. R-M systems are known for their role in the defense against foreign DNA; however, DNA methyltransferases also play functional roles in gene regulation. In this study, we used single-molecule real-time (SMRT) sequencing to uncover the genome-wide DNA methylation pattern in the opportunistic pathogen Pseudomonas aeruginosa PAO1. We identified a conserved sequence motif targeted by an adenine methyltransferase of a type I R-M system and quantified the presence of N(6)-methyladenine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Changes in the PAO1 methylation status were dependent on growth conditions and affected P. aeruginosa pathogenicity in a Galleria mellonella infection model. Furthermore, we found that methylated motifs in promoter regions led to shifts in sense and antisense gene expression, emphasizing the role of enzymatic DNA methylation as an epigenetic control of phenotypic traits in P. aeruginosa Since the DNA methylation enzymes are not encoded in the core genome, our findings illustrate how the acquisition of accessory genes can shape the global P. aeruginosa transcriptome and thus may facilitate adaptation to new and challenging habitats.IMPORTANCE With the introduction of advanced technologies, epigenetic regulation by DNA methyltransferases in bacteria has become a subject of intense studies. Here we identified an adenosine DNA methyltransferase in the opportunistic pathogen Pseudomonas aeruginosa PAO1, which is responsible for DNA methylation of a conserved sequence motif. The methylation level of all target sequences throughout the PAO1 genome was approximated to be in the range of 65 to 85% and was dependent on growth conditions. Inactivation of the methyltransferase revealed an attenuated-virulence phenotype in the Galleria mellonella infection model. Furthermore, differential expression of more than 90 genes was detected, including the small regulatory RNA prrF1, which contributes to a global iron-sparing response via the repression of a set of gene targets. Our finding of a methylation-dependent repression of the antisense transcript of the prrF1 small regulatory RNA significantly expands our understanding of the regulatory mechanisms underlying active DNA methylation in bacteria

Description of Xenorhabdus khoisanae sp. nov., the symbiont of the entomopathogenic nematode Steinernema khoisanae

The original publication is available at http://ijs.sgmjournals.org/content/63/Pt_9/3220.fullBacterial strain SF87T, and additional strains SF80, SF362 and 106-C, isolated from the nematode Steinernema khoisanae, are non-bioluminescent Gram-reaction-negative bacteria that share many of the carbohydrate fermentation reactions recorded for the type strains of recognized Xenorhabdus species. Based on 16S rRNA gene sequence data, strain SF87T is shown to be closely related (98 % similarity) to Xenorhabdus hominickii DSM 17903T. Nucleotide sequences of strain SF87 obtained from the recA, dnaN, gltX, gyrB and infB genes showed 96–97 % similarity with Xenorhabdus miraniensis DSM 17902T. However, strain SF87 shares only 52.7 % DNA–DNA relatedness with the type strain of X. miraniensis, confirming that it belongs to a different species. Strains SF87T, SF80, SF362 and 106-C are phenotypically similar to X. miraniensis and X. beddingii, except that they do not produce acid from aesculin. These strains are thus considered to represent a novel species of the genus Xenorhabdus, for which the name Xenorhabdus khoisanae sp. nov. is proposed. The type strain is SF87T ( = DSM 25463T = ATCC BAA-2406T).Post-prin

Characterization of the first cultured representative of a Bacteroidetes clade specialized on the scavenging of cyanobacteria

International audienceThe anaerobic, mesophilic and moderately halophilic strain L21-Spi-D4 T was recently isolated from the suboxic zone of a hypersaline cyanobacterial mat using protein-rich extracts of Arthrospira (formerly Spirulina) platensis as substrate. Phylogenetic analyses based on 16S rRNA genes indicated an affiliation of the novel strain with the Bacteroidetes clade MgMjR-022, which is widely distributed and abundant in hypersaline microbial mats and heretofore comprised only sequences of uncultured bacteria. Analyses of the complete genome sequence of strain L21-Spi-D4 T revealed a possible specialization on the degradation of cyanobacterial biomass. Besides genes for enzymes degrading specific cyanobacterial proteins a conspicuous transport complex for the polypeptide cyanophycin could be identified that is homologous to typical polysaccharide utilization loci of Bacteroidetes. A distinct and reproducible co-occurrence pattern of environmental 16S rRNA gene sequences of the MgMjR-022 clade and cyanobacte-ria in the suboxic zone of hypersaline mats points to a specific dependence of members of this clade on decaying cyanobacteria. Based on a comparative analysis of phenotypic, genomic and ecological characteristics we propose to establish the novel taxa Salinivirga cyanobacteriivorans gen. nov., sp. nov., represented by the type strain L21-Spi-D4 T , and Sali-nivirgaceae fam. nov., comprising sequences of the MgMjR-022 clade

High quality genome sequences of thirteen Hypoxylaceae (Ascomycota) strengthen the phylogenetic family backbone and enable the discovery of new taxa

Wibberg D, Stadler M, Lambert C, et al. High quality genome sequences of thirteen Hypoxylaceae (Ascomycota) strengthen the phylogenetic family backbone and enable the discovery of new taxa. FUNGAL DIVERSITY. 2020.The Hypoxylaceae (Xylariales, Ascomycota) is a diverse family of mainly saprotrophic fungi, which commonly occur in angiosperm-dominated forests around the world. Despite their importance in forest and plant ecology as well as a prolific source of secondary metabolites and enzymes, genome sequences of related taxa are scarce and usually derived from environmental isolates. To address this lack of knowledge thirteen taxonomically well-defined representatives of the family and one member of the closely related Xylariaceae were genome sequenced using combinations of Illumina and Oxford nanopore technologies or PacBio sequencing. The workflow leads to high quality draft genome sequences with an average N50 of 3.0 Mbp. A backbone phylogenomic tree was calculated based on the amino acid sequences of 4912 core genes reflecting the current accepted taxonomic concept of the Hypoxylaceae. A Percentage of Conserved Proteins (POCP) analysis revealed that 70% of the proteins are conserved within the family, a value with potential application for the definition of family boundaries within the order Xylariales. Also, Hypomontagnella spongiphila is proposed as a new marine derived lineage of Hypom. monticulosa based on in-depth genomic comparison and morphological differences of the cultures. The results showed that both species share 95% of their genes corresponding to more than 700 strain-specific proteins. This difference is not reflected by standard taxonomic assessments (morphology of sexual and asexual morph, chemotaxonomy, phylogeny), preventing species delimitation based on traditional concepts. Genetic changes are likely to be the result of environmental adaptations and selective pressure, the driving force of speciation. These data provide an important starting point for the establishment of a stable phylogeny of the Xylariales; they enable studies on evolution, ecological behavior and biosynthesis of natural products; and they significantly advance the taxonomy of fungi

Bacillus purgationiresistans sp. nov., isolated from a drinking-water treatment plant

A Gram-positive, aerobic, non-motile, endospore-forming rod, designated DS22T, was isolated from a drinking-water treatment plant. Cells were catalase- and oxidase-positive. Growth occurred at 15–37 6C, at pH 7–10 and with ,8% (w/v) NaCl (optimum growth: 30 6C, pH 7–8 and 1–3% NaCl). The major respiratory quinone was menaquinone 7, the G+C content of the genomic DNA was 36.5 mol% and the cell wall contained meso-diaminopimelic acid. On the basis of 16S rRNA gene sequence analysis, strain DS22T was a member of the genus Bacillus. Its closest phylogenetic neighbours were Bacillus horneckiae NRRL B-59162T (98.5% 16S rRNA gene sequence similarity), Bacillus oceanisediminis H2T (97.9 %), Bacillus infantis SMC 4352-1T (97.4 %), Bacillus firmus IAM 12464T (96.8 %) and Bacillus muralis LMG 20238T (96.8 %). DNA–DNA hybridization, and biochemical and physiological characterization allowed the differentiation of strain DS22T from its closest phylogenetic neighbours. The data supports the proposal of a novel species, Bacillus purgationiresistans sp. nov.; the type strain is DS22T (5DSM 23494T5NRRL B-59432T5LMG 25783T).info:eu-repo/semantics/publishedVersio