Systematic and applied microbiology最新文献

{"title":"An updated outlook at the planctomycetal genus Singulisphaera: New members, genomes, and functional roles.","authors":"Svetlana N Dedysh, Anastasia A Ivanova, Irina S Kulichevskaya, Daniil G Naumoff, Natalia E Suzina, Alexey V Beletsky, Andrey L Rakitin, Andrey V Mardanov, Nikolai V Ravin","doi":"10.1016/j.syapm.2026.126713","DOIUrl":"https://doi.org/10.1016/j.syapm.2026.126713","url":null,"abstract":"<p><p>The genus Singulisphaera accommodates stalk-free planctomycetes with spherical cells, which multiply by budding, possess complex cell organization, large genomes, and colonize a wide spectrum of terrestrial environments. Two described species of this genus, S. acidiphila and S. rosea, were isolated from acidic peatlands and characterized as mildly acidophilic bacteria. Here, we characterize two neutrophilic Singulisphaera isolates from a boreal fen, strains Ch08^T and PoT^T. We also obtained and analyzed the previously unavailable genome sequence of S. rosea S26^T. As confirmed by genome analyses and substrate utilization tests, all strains of Singulisphaera species were capable of growth on amorphous chitin due to the possession of chitinases affiliated with the glycoside hydrolase family GH18. The gene encoding chitinase from strain PoT^T was expressed in Escherichia coli, and the endochitinase activity of the recombinant enzyme was confirmed. The genomes also contained gene clusters encoding Planctomycetal-type bacterial microcompartment (BMC) organelles, suggesting participation of Singulisphaera species in degradation of plant-derived polysaccharides. Transcriptome analysis performed with glucose- and L-fucose-grown cells of strain PoT^T showed up-regulation of these BMC-encoding genes during growth on L-fucose. Tyrosinases involved in the oxidative removal of phenolic compounds were present only in S. acidiphila MOB10^T. All Singulisphaera genomes contained the genes of the recently identified pathway of ornithine lipid biosynthesis. Based on the reported results, we describe two novel species, S. photorubra and S. chitinilytica with the type strains Ch08^T (=KCTC 102485^T = LMG 34153^T) and PoT^T (=KCTC 102290^T = VKM B-3855^T), respectively. The emended description of the genus Singulisphaera is also proposed.</p>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 3","pages":"126713"},"PeriodicalIF":4.2,"publicationDate":"2026-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147499992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bradyrhizobium zaerense sp. nov., an efficient symbiotic nitrogen-fixing bacterium isolated from Lupinus luteus and Retama dasycarpa root nodules.","authors":"Zohra Chaddad, Kaoutar Kaddouri, Mouad Lamrabet, Soufiane Alami, Bacem Mnasri, Daniel Wipf, Pierre-Emmanuel Courty, Mustapha Missbah El Idrissi","doi":"10.1016/j.syapm.2026.126712","DOIUrl":"https://doi.org/10.1016/j.syapm.2026.126712","url":null,"abstract":"<p><p>Three strains, LLZ isolated from root nodules of Lupinus luteus in agricultural soils in the vicinity of Rabat, and seven strains RDM, isolated from nodules of Retama dasycarpa in Maamora forest soil, were assigned to a new lineage within the genus Bradyrhizobium. The present study provides a detailed taxonomic analysis of the representative strain LLZ17^T. Genome analysis revealed average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values far below the threshold (88.4% and 34%, respectively) with the closest type strains B. hipponense, B. rifense, and B. cytisi. Phylogenetic analyses using 81 up-to-date bacteria core genes and whole genome sequences grouped LLZ17^T and RDM4 in a highly supported lineage, distinct from described Bradyrhizobium species. The complete genome of LLZ17^T consists of a single 7.8 Mbp chromosome with a GC content of 63.19% and contains nitrogen fixation and nodulation genes required when forming root symbiosis. Furthermore, strains LLZ13, LLZ15, RDM4, RDM7, RDM9, RDM14, RDM15, RDM18, RDM30 and LLZ17^T were described phenotypically and compared with their closest Bradyrhizobium-type strains. Genomic and phenotypic characterization confirmed the ten strains are novel species. Strain LLZ17^T was designated as the type strain of this new species, for which the name Bradyrhizobium zaerense sp. nov. is proposed.</p>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 3","pages":"126712"},"PeriodicalIF":4.2,"publicationDate":"2026-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147491858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caldiplasma sukawensis gen. nov., sp. nov., and Cuniculiplasma thermophilum sp. nov., mesophilic, acidophilic, cell–wall–less, archaea of the order Thermoplasmatales, isolated from extremely acidic hot spring","authors":"Yuya Tsukamoto ,&nbsp;Hiroyuki D. Sakai ,&nbsp;Yoshinori Takano ,&nbsp;Toshiki Koga ,&nbsp;Arisa Nishihara ,&nbsp;Shigeru Kawai ,&nbsp;Susumu Yoshizawa ,&nbsp;Moriya Ohkuma","doi":"10.1016/j.syapm.2025.126686","DOIUrl":"10.1016/j.syapm.2025.126686","url":null,"abstract":"<div><div>Four mesophilic, acidophilic, cell wall–less archaea, strains—SKW1, SKW2^T, SKW3, and SKW4^T—were isolated from a green microbial mat in an acidic hot spring. SKW1 and SKW2^T cells were predominantly coccoid and rarely pleomorphic, whereas SKW3 and SKW4^T cells were mostly pleomorphic. The cell sizes ranged from 0.3 to 2.0 μm. SKW1 and SKW2^T grew at temperatures between 15 and 55 °C (optimally at 37–40 °C) and pH 1.5–5.0 (optimally 3.0–4.0). SKW3 and SKW4^T also grew at temperatures between 15 and 55 °C (optimally at 30 °C) and pH 1.5–5.0 (optimally 1.8–2.0). All the strains were facultatively anaerobic and heterotrophic, requiring tryptone for growth. The dominant membrane lipid in both SKW2^T and SKW3 was glycerol dibiphytanyl glycerol tetraether (GDGT). The genomic G+C mol% of SKW1 to SKW4^T ranged from 35.8 to 38.1 mol%. In the 16S rRNA gene–based phylogenetic tree, all the strains were placed within the family <em>Cuniculiplasmataceae</em> and the order Thermoplasmatales<em>.</em> Sequence identities to the closest strain, <em>Cuniculiplasma divulgatum</em> strain S5^T, were 94.28 % (SKW1), 94.35 % (SKW2^T), 95.81 % (SKW3), and 95.88 % (SKW4^T). Phylogenetic analyses showed that SKW 1 and SKW2^T were distantly related to <em>C. divulgatum</em> strain S5^T, whereas SKW3 and SKW4^T were more closely related. Based on phylogenetic analyses and physiological properties of the four isolates, a novel genus, <em>Caldiplasma</em> gen. nov.<em>,</em> and two novel species <em>Caldiplasma sukawensis</em> sp. nov. and <em>Cuniculiplasma thermophilum</em> sp. nov. are proposed: <em>Caldiplasma sukawensis</em> SKW1 (=JCM 39523) and SKW2^T (=JCM 39524^T), and <em>Cuniculiplasma thermophilum</em> SKW3 (=JCM 39525) and SKW4^T (=JCM 39526^T).</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126686"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145908846","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Desulfurivibrio nitratireducens sp. nov. and Desulfurivibrio modestus sp. nov., two novel alkaliphilic anaerobes isolated from terrestrial mud volcanoes","authors":"M.A. Khomyakova ,&nbsp;A.Y. Merkel ,&nbsp;D.S. Kopitsyn ,&nbsp;A.I. Slobodkin","doi":"10.1016/j.syapm.2026.126693","DOIUrl":"10.1016/j.syapm.2026.126693","url":null,"abstract":"<div><div>Anaerobic enrichments with 4-aminobenzoic acid and nitrate yielded two novel representatives of genus <em>Desulfurivibrio</em>. Strain C05AmB^T was isolated from terrestrial mud volcano Gnilaya Gora (Taman Peninsula, Russia), and strain D14AmB^T from terrestrial mud volcano Bakhar satellite (Azerbaijan). Both strains were mesophilic and alkaliphilic (pH optimum 9.0–9.5). The isolates were strict anaerobes with respiratory metabolism, utilizing organic substrates or molecular hydrogen as electron donors with sulfur compounds as electron acceptors. Strain C05AmB^T utilized additionally elemental sulfur and sulfide as electron donors with nitrate as electron acceptor, while strain D14AmB^T was incapable of nitrate reduction. Both strains can also disproportionate sulfur compounds including elemental sulfur, sulfite and thiosulfate. Major cellular fatty acids were C_16:0, C_16:1ω6c (the dominant fatty acid in strain C05AmB^T), C_18:0 and C_18:1 ω9c (the dominant fatty acid in strain D14AmB^T). The genomes had a size of 2.7–3.0 Mb for strains C05AmB^T and D14AmB^T respectively. Genome analysis allowed to identify the main pathways encoding carbon and energy metabolism. According to both phylogenetic analyses, based on 16S rRNA gene sequences and conserved protein sequences, as well as genome-based comparisons, each strain forms separate species-level lineage within <em>Desulfurivibrio</em> genus of <em>Desulfurivibrionaceae</em> family (phylum <em>Desulfobacterota</em>). Here we propose two novel species <em>Desulfurivibrio nitratireducens</em> sp. nov. with type strain C05AmB^T (=CGMCC 1.18106^T = VKM B-3838^T = KCTC 25857^T = UQM 41817^T) and <em>Desulfurivibrio modestus</em> sp. nov. with type strain D14AmB^T (=CGMCC 1.18059^T = VKM B-3769^T = UQM 41803^T). These are the first sulfur-disproportionating microorganisms isolated from terrestrial mud volcanoes.</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126693"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146126534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stenotrophomonas raiganjensis sp. nov., an extensively drug-resistant bacterium isolated from Bombyx mori L., described under the SeqCode","authors":"Rittick Mondal ,&nbsp;Atanu Manna ,&nbsp;Pankaj Mandal ,&nbsp;Halil Kurt ,&nbsp;Arnab Sen ,&nbsp;Kamlesh Jangid ,&nbsp;Amit Kumar Mandal","doi":"10.1016/j.syapm.2026.126699","DOIUrl":"10.1016/j.syapm.2026.126699","url":null,"abstract":"<div><div>SeqCode allows a single strain or a high-quality genome to serve as type material, making it compatible with modern genomics and biodiversity governance frameworks, especially for countries such as India. We, therefore, describe a novel bacterium, designated RAC2^TS under the SeqCode. RAC2^TS was isolated from the hemolymph of infected <em>Bombyx mori</em> L. and characterized using a polyphasic taxonomic approach. While 16S rRNA gene sequence based phylogenetics showed <em>Stenotrophomonas maltophilia</em> NBRC 14161ᵀ to be the closest relative, multilocus sequence analysis (MLSA) based on seven housekeeping genes (<em>atpD</em>, <em>gapA</em>, <em>guaA</em>, <em>mutM</em>, <em>nuoD</em>, <em>ppsA</em>, <em>recA</em>) and genome-based relatedness indices confirmed RAC2^TS as a distinct lineage within the genus <em>Stenotrophomonas</em>. Whole-genome analysis identified a 4.6 Mbp genome with 66.5% G + C content; and 4276 coding sequences, including several antimicrobial resistance genes alongside multidrug efflux pump <em>sme</em> operon genes and a single virulence-associated gene, <em>pilG</em>. RAC2^TS showed 91–93% average nucleotide identity (ANI) and 41–48% digital DNA-DNA hybridization (dDDH) with closely related taxa. Pangenome analysis revealed an open pangenome (α = 0.257), with 12,623 gene clusters including 229 core genes and 6994 strain-specific genes. Antibiotic susceptibility testing demonstrated extensive drug resistance (XDR) characteristics of RAC2^TS. Fatty acid methyl ester (FAME) analysis revealed isoC15:0 (24.56%), anteiso-C15:0 (14.27%), and summed feature 3 (16:1 ω7c/16:1 ω6c; 11.18%) as major components. Combined phenotypic, chemotaxonomic, phylogenomic, and genomic evidence supports the recognition of RAC2^TS as a novel species within the genus <em>Stenotrophomonas</em>. Under the SeqCode, we propose the name <em>S. raiganjensis</em> sp. nov. for strain RAC2^TS (=MCM-B-1506^TS) with the type genome GCA_030658505.2^TS.</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126699"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146259285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zongyangia acetica sp. nov. and Blautia acetica sp. nov., two acetate-producing bacteria isolated from human fecal in the order Eubacteriales","authors":"Hao-Yu Chen ,&nbsp;Xin-Wei Sun ,&nbsp;Hao-Jie Huang ,&nbsp;Wan-Qing Huang ,&nbsp;Chang Liu ,&nbsp;Shuang-Jiang Liu","doi":"10.1016/j.syapm.2026.126696","DOIUrl":"10.1016/j.syapm.2026.126696","url":null,"abstract":"<div><div>Two gram-stain positive, non-motile, spore-forming and anaerobic bacterial strains that are designated as HA2173^T and HA2174^T were isolated from the faeces of an adult woman. Physiological and biochemical analyses revealed that both strains are neutrophilic, mesophilic, and tolerant to low concentrations of NaCl. Analysis of 16S rRNA gene sequences indicated that strains HA2173^T and HA2174^T belonged to the families <em>Oscillospiraceae</em> and <em>Lachnospiraceae</em>, respectively. The phylogenetic relatives closest to strains HA2173^T and HA2174^T were <em>Zongyangia hominis</em> NSJ-54^T (16S rRNA gene similarity is 97.7%) and <em>Blautia argi</em> N6H1-15^T (16S rRNA gene similarity is 97.9%), respectively. Genome annotation indicated that both strains could metabolize carbohydrates and generate propionate, acetate and formate, and the major end-products of fermentation of both strains HA2173^T and HA2174^T were determined to be acetic acid. The major polar lipids detected in strain HA2173ᵀ were diphosphatidylglycerol and phosphatidylglycerol, but only diphosphatidylglycerol was identified in strain HA2174ᵀ. Cohort analysis revealed divergent prevalence patterns for strains HA2173ᵀ and HA2174ᵀ, with their relative abundances significantly elevated in the T2D and OB cohorts. Based on the results of phylogenetic analysis, 16S rRNA gene similarity, and chemotaxonomic characteristics, strains HA2173^T and HA2174^T represent novel species of the genus <em>Zongyangia</em> and <em>Blautia</em>, respectively, for which the names <em>Zongyangia acetica</em> sp. nov. and <em>Blautia acetica</em> sp. nov. are proposed. The type strain for <em>Zongyangia acetica</em> sp. nov. is HA2173^T (=CGMCC 1.18038^T = KCTC 25723^T). The type strain for <em>Blautia acetica</em> sp. nov. is HA2174^T (=CGMCC 1.18039^T = KCTC 25724^T)</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126696"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A phylogenomic and metagenomic meta-analysis of bacterial diversity in the phyllosphere lifts a veil on hyphomicrobiales dark matter","authors":"Jean-Baptiste Leducq ,&nbsp;Louis-Philippe St-Amand ,&nbsp;David Ross ,&nbsp;Steven W. Kembel","doi":"10.1016/j.syapm.2026.126697","DOIUrl":"10.1016/j.syapm.2026.126697","url":null,"abstract":"<div><div>The phyllosphere, or above-ground part of plants, hosts diverse bacterial communities that play critical ecological roles and provide beneficial functions for the plant. The Hyphomicrobiales (Alphaproteobacteria) are a highly diverse and ecologically important clade known to be key members of the plant microbiome, in particular in association with plant roots, but their diversity remains largely uncharacterized in the phyllosphere. Using a meta-analysis combining metabarcoding, metagenomics and phylogenomics, we explored the diversity of leaf-associated Hyphomicrobiales. We confirmed <em>Methylobacterium</em> was ubiquitous in the phyllosphere and revealed the dominance of two under-characterized Hyphomicrobiales taxa: Lichenihabitantaceae, a lichen-associated family previously identified as “<em>1174–901-12</em>” in taxonomic databases, and <em>RH-AL1</em>, an undescribed lineage of bacteria related to Beijerinckiaceae. Despite their abundance in the phyllosphere, Lichenihabitantaceae and RH_AL1 could not be properly identified by 16S rRNA gene barcoding, due in part to limitations of short read sequencing leading to a lack of recognition of certain Hyphomicrobiales genera, and to incongruencies in the assignment of genera to families among existing taxonomic databases. A significant proportion of Lichenihabitantaceae were detected in association with lichens and in environments with harsh conditions like exposed surfaces, air and snow. Overall, our study stresses the need to agree on a common systematic framework to properly classify and identify key leaf-associated Hyphomicrobiales taxa, and to move toward metagenomics and culturomics to increase their representation in reference databases, to provide a better understanding of the evolutionary and functional mechanisms underpinning bacteria adaptations to living on plants.</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126697"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Haladaptatus marinus sp. nov., Haladaptatus rarus sp. nov., Haladaptatus ordinarius sp. nov., and Halomicrococcus pelagicus sp. nov., halophilic archaea from diverse coastal tidal flats","authors":"Xin-Ru Zhang ,&nbsp;Jing Hou ,&nbsp;Zhen Rong ,&nbsp;Yue-Hong Wu ,&nbsp;Heng-Lin Cui","doi":"10.1016/j.syapm.2026.126698","DOIUrl":"10.1016/j.syapm.2026.126698","url":null,"abstract":"<div><div>Six novel halophilic archaeal strains, DFWS20^T, NG-SE-30^T, NG-WS-4^T, HHT-WS-8, NG-SE-24^T, and SG-WS-1, were isolated from different coastal regions of China. Metagenome and amplicon analyses showed that the abundance of archaea in the corresponding samples was very low. Strains DFWS20^T, NG-SE-30^T, NG-WS-4^T, and HHT-WS-8 were found to cluster with current <em>Haladaptatus</em> species, while strains NG-SE-24^T and SG-WS-1 with those of <em>Halomicrococcus</em> based on 16S rRNA and <em>rpoB’</em> gene phylogenies. The overall-genome related indexes (OGRIs), average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and average amino acid identity (AAI) values, between strains DFWS20^T, NG-SE-30^T, NG-WS-4^T, HHT-WS-8, and <em>Haladaptatus</em> species were 77.0–83.1%, 22.2–28.3%, and 74.7–84.8%, while those between strains NG-SE-24^T, SG-WS-1, and <em>Halomicrococcus</em> species were 79.6–94.9%, 26.0–63.9%, and 76.5–94.1%, respectively. These values were lower than the threshold of species classification. In contrast, the OGRIs between strains NG-WS-4^T and HHT-WS-8, as well as those between strains NG-SE-24^T and SG-WS-1, were above the threshold of species classification. Diverse differential phenotypic characteristics, such as nutrition, biochemical activities, and antibiotic sensitivity, were determined in these six strains and the existing species of the corresponding genera. The most abundant pathways in the genera <em>Haladaptatus</em> and <em>Halomicrococcus</em> were related to carbohydrate metabolism and amino acid metabolism. Based on the natural habitat analysis of the 16S rRNA genes of the strains, their target sequences were primarily found in habitats such as aquatic, soil, sediments, plant, and marine environments. The major polar lipids of strains DFWS20^T, NG-SE-30^T, NG-WS-4^T, and HHT-WS-8 were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), phosphatidylglycerol sulfate (PGS), and sulfated mannosyl glucosyl diether (S-DGD-1), while those of strains NG-SE-24^T and SG-WS-1 were PG, PGP-Me, S-DGD-1, and galactosyl mannosyl glucosyl diether (TGD-2). Based on these polyphasic classification, strains DFWS20^T, NG-SE-30^T, NG-WS-4^T, and HHT-WS-8 represent three novel species of the genus <em>Haladaptatus</em> while NG-SE-24^T and SG-WS-1 represent a novel species of the genus <em>Halomicrococcus</em>.</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126698"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146173606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anaeroglomus insulsum gen. nov., sp. nov., anaerobic planctomycete, isolated from a thermal water stream","authors":"M.A. Khomyakova ,&nbsp;A.Y. Merkel ,&nbsp;A.A. Novikov ,&nbsp;K.D. Davranov ,&nbsp;A.I. Slobodkin","doi":"10.1016/j.syapm.2026.126695","DOIUrl":"10.1016/j.syapm.2026.126695","url":null,"abstract":"<div><div>A novel obligately anaerobic bacterium (strain U12dextr^T) was isolated from sediment of a thermal water stream formed by discharge of artesian groundwater (Navoiy Region, Uzbekistan). The cells of the isolate were non-motile cocci, 0.5 to 0.8 μm in diameter forming chains or aggregates. The cells had a Gram-negative cell wall and divided by binary fission. The temperature range for growth was 37–47 °C (optimum at 42 °C). The pH range for growth was 5.5–7.5, with an optimum at pH 6.0–6.5. NaCl inhibited growth of strain U12dextr^T at concentration of 1% and higher. The new isolate fermented mono-, di- and polysaccharides (dextran, xanthan gum, <em>N</em>-acetylglucosamine), but did not utilize proteinaceous compounds. Major cellular fatty acids were C_20:0, i-C_16:0, i-C_14:0, and ai-C_15:0. The genome of strain U12dextr^T had a size of 3.4 Mb with a G + C content of 51.67%. Genome analysis revealed a large pool of CAZyme genes. The closest cultured phylogenetic relatives of strain U12dextr^T was <em>Anaerohalosphaera lusitana</em> (phylum <em>Planctomycetota</em>) with 16S rRNA gene sequence similarity 90.6%. We propose to assign strain U12dextr^T to a novel genus and species, <em>Anaeroglomus insulsum</em> gen. nov., sp. nov.; the type strain is U12dextr^T (=VKM B-3770^T = CGMCC 1.18105^T = UQM 41804^T). It is the first non-halophilic representative of the family <em>Anaerohalosphaeraceae.</em></div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126695"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146165924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Legionella petroniana sp. nov., a novel species isolated in Bologna, Italy: taxonomic, genomic and ecological insights in the era of environmental change","authors":"Sandra Cristino ,&nbsp;Laura Caligaris ,&nbsp;Silvano Salaris ,&nbsp;Carlo Derelitto ,&nbsp;Caterina Bonincontro ,&nbsp;Federica Marino ,&nbsp;Antonella Grottola ,&nbsp;Luna Girolamini","doi":"10.1016/j.syapm.2026.126694","DOIUrl":"10.1016/j.syapm.2026.126694","url":null,"abstract":"<div><div>This study presents the characterization of a novel <em>Legionella</em> species isolated in Italy over three different years from one company and two hospitals. Starting from standard techniques such as culture of water samples, agglutination test, MALDI–TOF MS and gene sequencing analysis used to identify the isolates, genomic and metabarcoding approaches were subsequently employees to further characterize the species. <em>Legionella</em> contamination ranged from 400 to 700 CFU/L. The tiny colonies displayed atypical morphology compared to typical <em>Legionella</em> features, although they grew on BCYE medium supplemented with L-cysteine. Microscopic and phenotypic analyses revealed Gram-stain negative, Ziehl-Neelsen-negative, rod-shaped, motile cells capable of growing at 32–37 °C, including on selective media such as GVPC and MWY. The isolates tested positive for oxidase and gelatinase activity. Fatty acid profiling identified the dominant components as Summed Features 3 (C16:1 ω7c/C16:1 ω6c, 28.9%), C16:0 iso (18.4%), and C15:0 anteiso (15.4%). Ubiquinone Q13 was the major quinone. Sequence analysis of the <em>mip</em> and <em>rpoB</em> genes showed 98.2% and 95.1% similarity, respectively, to <em>L. feeleii</em> (WO-44C ATCC 35072^T). Whole genome sequencing (WGS) revealed a GC content of 41.5%, a dDDH value of ≤54.9%, and an ANI of 94.06% with <em>L. feeleii</em> (WO-44C ATCC 35072^T), supporting the classification of a novel species within the genus <em>Legionella</em>. Furthermore, taxonomic resolution of water samples revealed the presence of 168 bacterial genera, including several respiratory, opportunistic, and zoonotic pathogens, as well as seven <em>Legionella</em> species<em>.</em> The name <em>Legionella petroniana</em> sp. nov. is proposed, with strain 31fI33^T (=DSM 114357^T=CCUG 76442^T) designated as type strain.</div></div>","PeriodicalId":22124,"journal":{"name":"Systematic and applied microbiology","volume":"49 2","pages":"Article 126694"},"PeriodicalIF":4.2,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146158561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}