http://192.168.1.40:8080/xmlui/handle/123456789/1150 2026-05-31T13:43:55Z http://192.168.1.40:8080/xmlui/handle/123456789/2408 Mesorhizobium thiogangeticum sp nov., a novel sulfur-oxidizing chemolithoautotroph from rhizosphere soil of an Indian tropical leguminous plant Ghosh, Wriddhiman; Roy, Pradosh The bacterial strain SJT(T), along with 15 other mesophilic, neutrophilic and facultatively sulfur-oxidizing chemolithotrophic isolates, was isolated by enrichment on reduced sulfur compounds as the sole energy and electron source from soils immediately adjacent to the roots of Clitoria ternatea, a slender leguminous herb of the Lower Gangetic plains of India. Strain SJT(T) was able to oxidize thiosulfate and elemental sulfur for chemolithoautotrophic growth. 16S rRNA and recA gene sequence-based phylogenetic analyses showed that the Gram-negative rod-shaped bacterium belonged to the genus Mesorhizobium and was most closely related to Mesorhizobium loti, Mesorhizobium plurifarium, Mesorhizobium amorphae and Mesorhizobium chacoense. Unequivocally low 16S rRNA (< 97%) and recA (<= 88%) gene sequence similarities to all existing species of the most closely related genera, a unique fatty acid profile, a distinct G+C content (59.6 mol%) and phenotypic characteristics all suggested that strain SJT(T) represents a novel species. DNA-DNA hybridization and SDS-PAGE analysis of whole-cell proteins also confirmed the taxonomic uniqueness of SJT(T). It is therefore proposed that isolate SJT(T) (= LMG 22697(T) = MTCC 7001(T)) be classified as the type strain of a novel species, Mesorhizobium thiogangeticum sp. nov. DOI: 10.1099/ijs.0.63967-0 2006-01-01T00:00:00Z http://192.168.1.40:8080/xmlui/handle/123456789/2406 Tetrathiobacter kashmirensis gen. nov., sp nov., a novel mesophilic, neutrophilic, tetrathionate-oxidizing, facultatively chemolithotrophic betaproteobacterium isolated from soil from a temperate orchard in Jammu and Kashmir, India Ghosh, Wriddhiman; Bagchi, A.; Mandal, S.; Dam, B.; Roy, Pradosh Twelve chemolithotrophic strains were isolated from temperate orchard soil on reduced sulfur compounds as energy and electron sources and characterized on the basis of their physiological properties and ability to oxidize various reduced sulfur compounds. The new isolates could oxidize tetrathionate as well as thiosulfate, and oxidation of the latter involved conversion of thiosulfate to tetrathionate followed by its accumulation and eventual oxidation to sulfate, manifested in the production of acid. The mesophilic, neutrophilic, Gram-negative and coccoid bacteria had a respiratory metabolism. Physiologically and biochemically, all the strains were more or less similar, differing only in their growth rates and ability to utilize a few carbon compounds as single heterotrophic substrates. 16S rRNA gene sequence analysis was performed with five representative strains, which revealed a high degree of similarity (>= 99%) among them and placed the cluster in the 'Betaproteobacteria'. The strains showed low levels (93 center dot 5-95 center dot 3 %) of 16S rRNA gene sequence similarity to Pigmentiphaga kullae, Achromobacter xylosoxidans, Pelistega europaea and species belonging to the genera Alcaligenes, Taylorella and Bordetella. The taxonomic coherence of the new isolates was confirmed by DNA-DNA hybridization. On the basis of their uniformly low 16S rRNA gene sequence similarities to species of all the closest genera, unique fatty acid profile, distinct G+C content (54-55 center dot 2 mol%) and phenotypic characteristics that include efficient chemolithotrophic utilization of tetrathionate, the organisms were classified in a new genus, Tetrathiobacter gen. nov. In the absence of any significant discriminatory phenotypic or genotypic characteristics, all the new isolates are considered to constitute a single species, for which the name Tetrathiobacter kashmirensis sp. nov. (type strain WTOO1(T) = LMG 22695(T) = MTCC 7002(T)) is proposed. DOI: 10.1099/ijs.0.63595-0 2005-09-01T00:00:00Z http://192.168.1.40:8080/xmlui/handle/123456789/2404 Paracoccus bengalensis sp nov., a novel sulfur-oxidizing chemolithoautotroph from the rhizospheric soil of an Indian tropical leguminous plant Ghosh, Wriddhiman; Mandal, S; Roy, P. Paracoccus versutus-like isolates from the rhizosphere of Clitoria ternatea, a slender leguminous herb (family Papilionaceae), found ubiquitously in waste places and village forests of the Lower Gangetic plains of India, presented a case of graduated infraspecific variation that was capped by the identification of a new species Paracoccus bengalensis (type strain JJJ(T) = LMG 22700T = MTCC 7003(T)). The diverged phenetic and genetic structure of these sulfuroxidizing chemolithoautotrophs presented a case of apparent nonconformity of 16S rRNA gene sequence similarities with results of DNA DNA hybridization. Despite high 16S rRNA gene sequence similarity with P. versutus one of the newly isolated strains, viz., JJJ(T) was identified as a new species of Paracoccus by virtue of its explicitly low DNA-DNA hybridization (42-45%) with the type strain of the closest species P. versutus (ATCC 25364 T), distinct G + C content (65.3mol%), physiological and biochemical differences amounting to < 60% phenetic similarity with strains of P. versutus as well as new isolates akin to the species. The newly described species also had a unique fatty acid profile that was distinguished by the absence of 18:1 omega 9c, unique possession of Summed feature 3 (16: 1 omega 7c & 15:0 iso 2-OH), 19:0 10 methyl, and a much higher concentration of 19:0 cyclo omega 8c. DOI: 10.1016/j.syapm.2005.10.004 2006-07-01T00:00:00Z http://192.168.1.40:8080/xmlui/handle/123456789/2168 Ubiquitous presence and activity of sulfur-oxidizing lithoautotrophic microorganisms in the rhizospheres of tropical plants Ghosh, Wriddhiman; Roy, Pradosh 2006-07-25T00:00:00Z