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Objective: The family Paenibacillaceae is linked to the order Caryophanales. Paenibacillaceae members residing in compost or soil play crucial roles in nutrient recycling and breaking down complex organic materials. However, our understanding of Paenibacillaceae remains limited., Methods: Strain SYSU GA230002 T was conclusively identified using a polyphasic taxonomic approach frequently utilized in bacterial systematics. Standard microbiological techniques were employed to characterize the morphology and biochemistry of strain SYSU GA230002 T ., Results: An anaerobic and gram--negative bacterium, designated SYSU GA230002 T , was isolated from geothermally heated soil of Tengchong, Yunnan Province, south-west China. Phylogenetic analyses based on 16S rRNA gene sequences and genomes showed that strain SYSU GA230002 T belongs to the family Paenibacillaceae. 16S rRNA gene sequence similarity (<94.0 %), ANI (<71.95 %) and AAI values (<58.67 %) between strain SYSU GA230002 T with other members of the family were lower than the threshold values recommended for distinguishing novel species. Growth was observed at 30-45 °C (optimum, 37 °C), pH 7.0-8.0 (optimum, pH 7.5) and in 0-3.0 % (w/v) NaCl concentrations (optimum, 0 %). The major fatty acids detected were anteiso-C 15:0 , iso-C 16:0 and iso-C 17:0 . The polar lipids included diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified phospholipid, one unidentified aminolipid and two unidentified glycolipids. The respiratory quinone was MK-7. The DNA G + C content of strain SYSU GA230002 T was 49.87 %., Conclusion: Based on the results of morphological, physiological properties, and chemotaxonomic characteristics, this strain is proposed to represent a new species of a new genus Ferviditalea candida gen. nov., sp. nov. The type strain of the type species is SYSU GA230002 T (=KCTC 25726 T  = GDMCC 1.4160 T )., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An isolate, designated CFH 74404 T , was recovered from a hot spring in Tengchong, Yunnan province, PR China. Phylogenetic analysis indicated that the isolate belongs to the family Thermomicrobiaceae and showed the highest 16S rRNA gene sequence similarity to Thermorudis peleae KI4 T (93.6 %), Thermorudis pharmacophila WKT50.2 T (93.1 %), Thermomicrobium roseum DSM 5159 T (92.0 %) and Thermomicrobium carboxidum KI3 T (91.7 %). The average amino acid identity and average nucleotide identity values between strain CFH 74404 T and the closest relatives were 42.0-75.9 % and 67.0-77.3 %, respectively. Cells of strain CFH 74404 T stained Gram-positive and were aerobic, non-motile and short rod-shaped. Growth occurred at 20-65 °C (optimum, 55 °C), pH 6.0-8.0 (optimum, pH 7.0) and with up to 2.0 % (w/v) NaCl (optimum 0-1.0 %, w/v). The predominant respiratory quinone was MK-8. The major fatty acids (>10 %) were C 18 : 0 (50.8 %) and C 20 : 0 (16.8 %). The polar lipid profile of strain CFH 74404 T included diphosphatidylglycerol, four unidentified phosphoglycolipids, phosphatidylinositol and three unidentified glycolipids. The G+C content of the genomic DNA was determined to be 67.1 mol% based on the draft genome sequence. On the basis of phenotypic, phylogenetic and genotypic analyses, it is concluded that strain CFH 74404 T represents a new species of a novel genus Thermalbibacter of the family Thermomicrobiaceae , for which the name Thermalbibacter longus gen. nov., sp. nov. is proposed. The type strain is CFH 74404 T (=KCTC 62930 T =CGMCC 1.61585 T ).

Objectives: Genus Clostridium sensu stricto is generally regarded as the true Clostridium genus, which includes important human and animal pathogens and industrially relevant microorganisms. Besides, it is also a prominent member of plant-associated endophytes. However, our knowledge of endophytic Clostridium is limited., Methods: In this study, the endophytes were isolated under anaerobic condition from the roots of Paris polyphylla Smith var. yunnanensis. Subsequently, a polyphasic taxonomic approach was used to clarify their taxonomic positions. The fermentation products were measured in the isolates with HPLC analysis. Comparative genomics was performed on these new strains and other relatives., Results: In total, nine endophytic strains belonging to the genus Clostridium sensu stricto were isolated, and three of them were identified as new species. Seven of nine strains could produce acetate, propionate, and butyrate. Only two strains could produce ethanol, although genomics analysis suggested that only two of them were without genes for solventogenesis. Different from the endophytic strains, the phylogenetically closely related non-endophytic strains showed significant enrichment effects on some metabolic pathways involving environmental information processing, carbohydrate, and amino acid metabolisms, etc. It suggests that the genomes of these endophytic strains had undergone subtle changes associated with environmental adaptations., Conclusion: Consequently, strains YIM B02505 T , YIM B02515 T , and YIM B02565 T are proposed to represent a new species of the genus Clostridium sensu stricto, for which the names Clostridium yunnanense sp. nov., Clostridium rhizosphaerae sp. nov., and Clostridium paridis sp. nov. are suggested., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

A novel anaerobic bacterium, designated SYSU GA19001 T , was isolated from a hot spring sediment sample. Phylogenetic analysis indicated that the isolate belongs to the genus Clostridium , and showed the highest sequence similarity to Clostridium swellfunianum CICC 10730 T (96.63 %) and Clostridium prolinivorans PYR-10 T (96.11 %). Cells of strain SYSU GA19001 T were Gram-stain-positive, spore-forming, rod-shaped (0.6-0.8×2.6-4.0 µm) and motile. Growth was observed at pH 5.0-9.0 (optimum, pH 7.0), 37-55 °C (optimum, 45 °C) and in NaCl concentrations of 0-2.0 % (optimum, 0 %). The genomic DNA G+C content was 31.62 %. The major cellular fatty acids of strain SYSU GA19001 T were C 14 : 0 , iso-C 15 : 0 , C 16 : 0 and summed feature 8. The prominent polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol. Meso -diaminopimelic acid was the diamino acid in peptidoglycan. Based on the results of phylogenetic, chemotaxonomic and phenotypic analyses, strain SYSU GA19001 T represents a novel species of the genus Clostridium , for which the name Clostridium caldaquaticum sp. nov. is proposed. The type strain of the proposed novel species is SYSU GA19001 T (=NBRC 115040 T = CGMCC 1.17864 T ).

Phylogenomic analyses were performed on the nine species of the genus Meiothermus and four species of the genus Calidithermus. Phylogenetic analysis, low values of genomic relatedness indices and functional diversity analysis indicated that Meiothermus silvanus should not be classified within the clades for Meiothermus and Calidithermus but instead be reclassified as a new genus, for which we propose the name Allomeiothermus gen. nov., with Allomeiothermus silvanus comb. nov. as type species. In addition, the species Meiothermus cateniformans Zhang et al. (Int J Syst Evol Microbial 60:840-844, 2010) should also be reclassified as a later heterotypic synonym of Meiothermus taiwanensis Chen et al. (Int J Syst Evol Microbiol 52:1647-1654, 2002) emend. Raposo et al. (2019). This reclassification is based on the high genomic relatedness indices (98.8% ANI; 90.2% dDDH; 99% AAI) that are above the threshold values necessary for defining a new species, as well as on the observation of overlapping functions on Principal Coordinate Analysis plot generated from Clusters of Orthologous Genes., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)