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A Gram-stain-negative, aerobic, capsule-forming strain, designated DAS-389 T , was isolated from soil collected in the Kogelberg Nature Reserve, Western Cape, South Africa. The strain formed small pink colonies, with cells that multiplied by binary division. Optimum growth was observed at 20 °C to 26 °C and pH 5.5 to 6.5, and it tolerated a NaCl concentration up to 1.5% (w/v). DAS-389 T is chemoorganotrophic, with growth substrate preferences for sugars and polysaccharides, including fructose and starch, respectively. The genome of DAS-389 T had a genome size of 4,136,282 bp with an average G+C content of 63.49 mol% and encodes for an assortment of enzymes, carbohydrate metabolic pathways and several genes involved in stress and survival responses. Major fatty acids (>5%) of strain DAS-389 T were iso-C15:0, iso-C17:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c) and summed feature 9 (iso-C17:1 ω9c and/or C16:0 10-methyl). Comparative analysis of 16S rRNA gene sequences revealed that strain DAS-389 T shared the highest similarity with Alloacidobacterium dinghuense 4Y35 T (96.6%), followed by Acidipila rosea AP8 T (96.6%) and Paracidobacterium acidisoli 4G-K13T (96.3%). Phylogenetic analysis based on 16S rRNA gene sequences and the whole proteome placed DAS-389 T within a distinct clade, separate from recognized genera in the family Acidobacteriaceae . We therefore propose that strain DAS-389ᵀ represents a novel genus and species, Candidatus Dedyshia acidiphila gen. nov., sp. nov., within the family Acidobacteriaceae , order Terriglobia . The whole-genome sequence of strain DAS-389ᵀ [accession number: JBMGJV000000000 (PRJNA1221820) ] is designated as the nomenclatural type.

A hydrogenotrophic methanogen, designated strain ACI-7 T , was isolated from an alkaline, saline wetland located in eastern Nebraska, USA. Cells were identified as non-motile rods (0.9–4.2 µm in length and 0.2–0.4 µm in diameter) that occurred singly, in chains, or as twisted chains and aggregates. Strain ACI-7 T utilized H 2 +CO 2 or formate as methanogenic substrates and required growth factors present in yeast extract for continuous cultivation. The strain grew at 20–45 °C (optimum, 40 °C), at pH 6.5–8.5 (optimum, pH 7.3) and with 0–2.5% NaCl (optimum, 0–1%). The genomic G+C content of ACI-7 T was 31.79 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated strain ACI-7 T was affiliated with the genus Methanobacterium , most closely related to Methanobacterium oryzae FPi T (97.1% sequence similarity) and Methanobacterium veterum MK4 T (96.9% sequence similarity). Overall genome relatedness indices for strain ACI-7 T compared to other Methanobacterium species ranged from 68.45 to 78.17% for average nucleotide identity and 18.9 to 25.7% for digital DNA–DNA hybridization. Morphological, physiological and genomic characteristics indicate that strain ACI-7 T represents a novel species, for which the name Methanobacterium nebraskense sp. nov. is proposed. The type strain is ACI-7 T (=DSM 118696 T =ATCC TSD-487 T ).

Abstract Multicellular magnetotactic prokaryotes represent a unique group of obligately marine multicellular bacteria known for their ability to navigate along magnetic field lines thanks to ferrimagnetic nanocrystals. To date, two distinct spherical and ellipsoidal morphotypes have been described, typically ranging from 3 to 6 μm in diameter and comprising approximately 50 cells of the same species. Although widespread in highly reduced marine sediments, they are represented by solely three genera clustering into a monophyletic group within the Desulfobacterota. In this study, we report a third morphotype in reduced sediments of the Mediterranean Sea in Carry-le-Rouet, France, that is approximately 30 times more voluminous than any previously described form. Because their large size, we designated these multicellular bacteria as “giant” and explored their cell ultrastructure, ecological niche and physiology using magnetic enrichment and a combination of microscopy techniques and single-consortium genomics. Transmission electron microscopy and confocal microscopy images of several individual consortia revealed that they contain an average of 130 cells, each producing over 100 greigite magnetosomes arranged to optimize the overall magnetic moment. Phylogenomic analyses positioned giant multicellular magnetotactic prokaryotes, together with other morphotypes, in a previously undescribed genus and species within the Candidatus Magnetomoraceae family, named Magnetogigantoglobus mediterraneus. Although genetically divergent with a different ultrastructure, all multicellular magnetotactic prokaryotes seem to rely on sulfate reduction coupled to heterotrophy or autotrophy. We further discuss the significance of these findings in the context of the evolutionary history of multicellularity and magnetotaxis in prokaryotes.

An anaerobic, salt-tolerant, rod-shaped bacterium, strain JL216-2 T , was isolated from the shell of the hydrothermal gastropod Alviniconcha marisindica in the Tianxiu hydrothermal field on the Carlsberg Ridge, Indian Ocean. Cells of strain JL216-2 T were motile and 0.5×3–6 µm in size. Strain JL216-2 T grew at 10–32 °C (optimal 28 °C), pH 6.0–9.0 (optimal pH 7.0) and 0.5–12.0% (w/v) sodium chloride(NaCl, optimal 2.5%). Strain JL216-2 T exhibited metabolic versatility, being capable of heterotrophic growth on complex organic compounds. It also performed autotrophic growth by utilizing carbon dioxide (CO₂) fixation or sodium bicarbonate (NaHCO 3 ) as the sole carbon source, driven by hydrogen oxidation coupled with Fe(III) reduction. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain was most closely related to Helicovermis profundi S502 T (90.43% sequence similarity). The genome size of strain JL216-2 T was 4.91 Mb, with a G+C content of 39.54 mol%. Phylogenomic analysis and overall genome relatedness indices values indicated a close relatedness of strain JL216-2 T to H. profundi S502 T and Fusibacter spp. The combined genotypic and phenotypic data showed that strain JL216-2 T represents a novel genus within the order Eubacteriales . The type strain is JL216-2 T (=MCCC M30262 T =KACC 23553 T ).

Background: Ticks are significant vectors of pathogens, and their nonpathogenic intracellular bacteria, known as endosymbionts, influence tick physiology and may interact with tick-borne pathogens. Such relationships can affect transmission dynamics and understanding them is essential for designing strategies that control tick-borne diseases and reduce their impact on human and animal health. Aim: This study aimed to determine the prevalence and density of two key endosymbiotic bacteria, Francisella-like endosymbiont (FLE) and Candidatus Midichloria mitochondrii (Ca. M. mitochondrii), and to investigate possible correlations between these symbionts and the protozoan parasite Theileria annulata in Hyalomma anatolicum ticks. Methods: Between January and October 2024, 116 ticks were collected from cattle in the Diwaniyah province, Iraq. The morphological examination was followed by molecular confirmation using mitochondrial 16S rRNA sequencing. Quantitative polymerase chain reaction was applied to detect and quantify FLE, Ca. M. mitochondrii, and T. annulata in H. anatolicum. Results: H. anatolicum was the predominant species, representing 86% of ticks, whereas H. excavatum accounted for 13%. Mitochondrial 16S rRNA sequences confirmed species identity and showed 99.48-100% similarity to reference isolates from China, Pakistan, Turkey, India, and Russia. FLE was detected in 100% of H. anatolicum, with mean loads of 7.9× 103 copies per tick. Ca. M. mitochondrii was detected in 99% of specimens, with mean loads of 3.7×102 copies per tick. FLE densities tended to be higher in females compared to males (9.7 × 10³ copies vs. 1.8 × 10³ copies) but difference was not statistically significant. Ca. M. mitochondrii loads also differed significantly (4.8 × 10² copies vs. 1.3 × 10¹ copies). T. annulata was present in all ticks, with the highest copy numbers in semi-engorged females (1.9 × 104 copies), followed by males (2.8 × 10³ copies). Our findings revealed a statistically significant association (p<0.05) between T. annulata and Ca. M. mitochondrii, whereas no significant correlation was observed between T. annulata and FLE. Conclusion: The presence of FLE and Ca. M. mitochondrii in H. anatolicum from the Diwaniyah province was documented. Evidence indicated associations between symbiont density and T. annulata infection, and the results point toward a possible role of endosymbiotic bacteria in pathogen persistence and the epidemiology of tick-borne diseases.

Bacteria involved in the anaerobic degradation of lignocellulosic waste in landfill sites play crucial roles in carbon turnover and biogas generation. In this study, we isolated and characterized a novel anaerobic bacterium, strain meth-B3ᵀ, from a laboratory-scale methanogenic bioreactor fed with maize-based biomass. Cells were Gram-stain-negative, non-spore-forming, motile rods with optimal growth at 35 °C, pH 7.0 and 0.7% sodium chloride (NaCl). Strain meth-B3ᵀ utilized a broad spectrum of carbohydrates, amino acids and organic acids, including glucose, cellobiose, glycerol, sucrose, maltose and various nitrogenous compounds. It fermented glucose into acetate, butyrate, lactate, propionate, valerate and ethanol. Whole-genome sequencing revealed a 3.8 Mbp genome with a G+C content of 62.65 mol%. Phylogenomic analyses based on 16S rRNA and conserved marker genes placed strain meth-B3ᵀ within the order Eubacteriales , forming a distinct clade from other known families. Comparative genomic metrics (average nucleotide identity, ≤69.4%; average amino acid identity, ≤54.2%; percentage of conserved protein, ≤35.2%) confirmed that strain meth-B3ᵀ represents a novel genus and family. Notably, carbohydrate-active enzyme and Clusters of Orthologous Groups (COG) functional profiling revealed an extensive suite of enzymes with potential activities against cellulose, xylan, starch and other maize-derived polymers, underscoring its ecological and biotechnological relevance in biomass degradation and biogas production. On the basis of genotypic and phenotypic distinctions, we propose the name Anaerozeibacter quisquiliarum gen. nov., sp. nov., with strain meth-B3ᵀ (=DSM 112769ᵀ=ATCC TSD-269ᵀ) being the type strain, and designate Anaerozeibacteraceae fam. nov. within the order Eubacteriales to accommodate this lineage.

ABSTRACTDespite recent genomic studies and increased molecular data, epitheliocystis remains an enigmatic fish disease with no experimental in vitro or in vivo models to aid the advancement of research. In this study, we revert to a classical microscopical approach and screen with the electron microscope the epitheliocystis lesions caused by a Ca. Parilichlamydia sp., infecting mucus cells in Greater amberjack. We report distinct morphological features of this bacterial family, characterised by Intermediate Bodies that closely resemble those of previously described Candidatus similchlamydia, and Elementary Bodies that exhibit morphological similarities to Chlamydia trachomatis. We describe the characteristics of a novel Chlamydial Inclusion Membrane (IM) type, with abundant interdigitations, possibly shaped by fusion of the IM with cytoplasmic vesicles, and moreover discuss the presence of multivesicular bodies in the infected cell. Our observation of immune cells in the infected areas indicates an interaction of macrophages with infected cells, a role for granular cells as pathogens reservoirs and an active phagoptosis process in the nearby areas, overall shedding light on cellular immune processes characterising these infections in fish hosts.

A novel bacterial strain UR115T belonging to the class Alphaproteobacteria was isolated from tomato rhizosphere soil. Strain UR115T was Gram-stain-negative, motile, facultative anaerobic, catalase positive, oxidase positive and rod shaped. Strain UR115T showed growth at 15–37 °C, pH 5.5–9.5 and up to 4.0% NaCl. Strain UR115T exhibited 16S rRNA gene sequence similarities of <90.40% with members of the class Alphaproteobacteria. Based on the phylogenetic analysis inferred from both 16S rRNA gene and whole-genome sequences, strain UR115T formed a separate and distinct clade, leading to its classification as a member of a novel order within the class Alphaproteobacteria. The genome size and G+C content of strain UR115T were 5,059,753 bp and 63.9%, respectively. Average amino acid identity values between strain UR115ᵀ and reference genomes ranged from 47.85% to 59.96%, and pairwise Percentage of Conserved Protein values ranged from 4.12% to 46.63%. The major cellular fatty acids of strain UR115T were C19 : 0 cyclo ω8c, C16 : 0 and summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c). The polar lipids of strain UR115T were phosphatidylethanolamine, phosphatidylglycerol, unidentified aminophospholipid, two unidentified aminolipids and two unidentified lipids. The predominant quinone was ubiquinone-10. Based on its distinct phylogenetic position, unique genomic characteristics and chemotaxonomic profiles, we proposed the novel species Radicibacter daui gen. nov., sp. nov., the novel family Radicibacteraceae fam. nov. and the novel order Radicibacterales ord. nov. The type strain is strain UR115T (=KACC 23674T=JCM 36738T).

A Gram-negative, facultative anaerobic, rod-shaped, motile with peritrichous flagella, fluorescent bacterium, designated ‘Candidatus Pseudomonas auctus’ sp. nov. JDE115, was isolated from soybean root nodules in Virginia and characterized using a comprehensive integrative methodology. Growth of JDE115 occurred with 0–5.0% (w/v) NaCl (optimum 1%), at pH 6.0–10.0 (optimum pH 7.0), and at 10–40°C (optimum 28°C) in LB broth. Phylogenetic analyses based on the 16S rRNA gene placed the isolate as a member of a novel species within the genus Pseudomonas. Phylogenetic analyses based on whole-genome sequences, 16S rRNA, showed JDE115 having the highest similarity to Pseudomonas glycinae MS586. Average Nucleotide Identity (ANI) analysis also revealed the highest similarity of JDE115 to Pseudomonas glycinae MS586 (94.59%), which is below the 95% threshold for species delineation. Genome-to-genome distance analysis (GGDC, Formula 2) showed a maximum value of 57.10% with the same strain, far below the 70% cutoff. The primary isoprenoid quinone detected in JDE115 was ubiquinone-9 (Q-9) and the DNA G + C content was 60.68 mol%. The whole-cell fatty acid profile was dominated by C16:0, C17:0 cyclo, and the summed features 3 (C16:1ω7c and/or C16:1ω6c) and 8 (C18:1ω7c and/or C18:1ω6c). Additional fatty acids detected included 12:0, 14:0, and 18:0. Based on these phenotypic, chemotaxonomic, and phylogenetic data, strain JDE115 is proposed to represent a new species in the genus Pseudomonas, for which the name ‘Candidatus Pseudomonas auctus’ sp. nov. is proposed.

A Gram-stain-negative, aerobic, non-motile and short rod-shaped bacterium, designated strain SCSIO 64248T, was isolated from the stony coral Fungia sp. collected from South China Sea. Phylogenetic analysis indicated that strain SCSIO 64248T belonged to the family Geminicoccaceae and showed the highest 16S rRNA gene similarities with the types of Marinimicrococcus flavescens (90.5%), Arboricoccus pini (90.2%) and Benzoalithermus flavus (89.8%). The whole genome of strain SCSIO 64248T was 4.9 Mbp with a 68.8mol% G+C content. It shared average amino acid identity (AAI) values of 52–56.2%, which is below the proposed AAI threshold at the genus level and when compared to the known species of Geminicoccaceae. Colonies of strain SCSIO 64248T are circular, pink and convex. It was able to grow in the range of 4–37 °C, at pH 6.0–10.0 and in the presence of up to 8.0% (w/v) NaCl concentration. The major cellular fatty acid (>9%) was summed feature 8, C19 : 0 cyclo ω8c and C16 : 0, and the sole respiratory quinone was Q-10. The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and an unidentified phospholipid. Data of polyphasic characteristics revealed that strain SCSIO 64248T represented a novel species of a new genus within the family Geminicoccaceae, for which the name Marinivivus gen. nov. is proposed with the type strain of the type species Marinivivus vitaminiproducens SCSIO 64248T (=MCCC 1K08013T=KCTC 92503T).