Taxonomic Reframe of Some Species of the Genera Haloferax and Halobellus.

Haloferax and Halobellus are the representatives of the family Haloferacaceae and they are dominant in hypersaline ecosystems. Some Haloferax and Halobellus species exhibit a close evolutionary relationship. Genomic, phylogenetic (based on 16S rRNA gene sequence), and phylogenomic analysis were performed to evaluate the taxonomic positions of the genera Haloferax and Halobellus. Based on the results we propose to reclassify Halobellus ramosii as a later heterotypic synonym of Halobellus inordinatus; Haloferax lucentense and Haloferax alexandrinum as later heterotypic synonyms of Haloferax volcanii.

Reclassification of Some Exiguobacterium Species Based on Genome Analysis.

The Exiguobacterium genus comprises Gram-stain-positive and facultatively anaerobic bacteria. Some Exiguobacterium species have previously shown significant high 16S rRNA gene sequence similarities with each other. This study evaluates the taxonomic classification of those Exiguobacterium species through comprehensive genome analysis. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values were determined for various Exiguobacterium species pairs. The ANI and dDDH values between Exiguobacterium enclense and Exiguobacterium indicum, Exiguobacterium aquaticum and Exiguobacterium mexicanum, Exiguobacterium soli and Exiguobacterium antarcticum, and Exiguobacterium sibiricum and Exiguobacterium artemiae were above the cut-off level (95-96% for ANI and 70% for dDDH) for species delineation. Based on the findings, we propose to reclassify Exiguobacterium enclense as a later heterotypic synonym of Exiguobacterium indicum, Exiguobacterium aquaticum as a later heterotypic synonym of Exiguobacterium mexicanum, Exiguobacterium soli as a later heterotypic synonym of Exiguobacterium antarcticum and Exiguobacterium sibiricum as a later heterotypic synonym of Exiguobacterium artemiae.

Assessing the metabolism, phylogenomic, and taxonomic classification of the halophilic genus Halarchaeum.

In this study, a genomic approach was employed to evaluate the metabolic potentials and taxonomic classification of the halophilic genus Halarchaeum. Genomic analysis revealed that Halarchaeum members exhibit a predilection for amino acids as their primary energy source in high-salinity environments over carbohydrates. Genome analysis unveiled the presence of crucial genes associated with metabolic pathways, including the Embden-Meyerhof pathway, semi-phosphorylative Entner-Doudoroff pathway, and the urea cycle. Furthermore, the genomic analysis indicated that Halarchaeum members employ diverse mechanisms for osmotic regulation (encompassing both salt-in and salt-out strategies). Halarchaeum members also encode genes to alleviate acid and heat stress. The average nucleotide identity value between Halarchaeum solikamskense and Halarchaeum nitratireducens exceeded the established threshold (95%-96%) for defining distinct species. This high similarity suggests a close relationship between these two species, prompting the proposal to reclassify Halarchaeum solikamskense as a heterotypic synonym of Halarchaeum nitratireducens. The results of this study contribute to our knowledge of taxonomic classification and shed light on the adaptive strategies employed by Halarchaeum species in their specific ecological niches.

Allostreptomyces indica sp. nov., isolated from India.

A novel actinobacterium, designated strain YIM 75704T, was isolated from a limestone quarry located at Gulbarga, Karnataka, India. The novel strain has showed typical morphological and chemotaxonomic characteristics of the family Streptomycetaceae. Comparison of 16S rRNA gene sequences indicated that this strain represents a novel member of the family Streptomycetaceae and exhibited 99.0% 16S rRNA gene sequence similarities with the type species of the recently described novel genus Allostreptomyces, that is, Allostreptomyces psammosilenae, whereas other species of Streptomyces were below 95% sequence similarity. The cell hydrolysates contained the LL-isomer of diaminopimelic acid and the predominant quinones were MK-9 (H6, H8 and H4). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylinositolmannosides and three unknown phospholipids. The DNA G+C content was 75.0 mol%. A polyphasic study of the strain with morphological, phenotypic, phylogenetic and with DNA-DNA hybridization evidence with related members showed that this strain represents novel species of Allostreptomyces for which the name Allostreptomyces indica sp. nov., is proposed. The type strain is YIM 75704T (= DSM 41985T=CCTCC AA 209051T= NCIM 5485T).

Actinorectispora indica gen. nov., sp. nov. isolated from soil, a member of the family Pseudonocardiaceae.

The taxonomic positions of three Gram-stain-positive, aerobic strains, designated YIM 75722, 75726 and 75728T, and isolated from a soil sample collected from Kurnool of Andhra Pradesh province, India, were assessed using a polyphasic approach. Growth was observed at pH 7.0-10.0 (optimum pH 7.0), 15-28 °C (optimum 28 °C) and 0-8 % (w/v) NaCl (grew without NaCl). Strains showed cylindrical spores with straight-chain morphology on aerial mycelium, but did not reveal sporangium-like structures or fragmentation of the substrate mycelium. Whole-cell hydrolysates of all strains contained galactose and ribose as the diagnostic sugars and meso-diaminopimelic acid as the diamino acid. The predominant menaquinone was MK-9(H4); MK-9 (H6) and MK-10 (H4) were present in smaller amounts. The phospholipid pattern consisted mainly of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylcholine. The major fatty acids were i-C15 : 0, ai-C15 : 0, i-C17 : 0 and ai-C17 : 0. The genomic DNA G+C content was 68.0 mol%. Phylogenetic analysis, based on 16S rRNA gene sequences, revealed that strain YIM 75728T should be placed within the family Pseudonocardiaceae, in which the strain formed a distinct lineage. The combination of phylogenetic analysis, phenotypic characteristics and chemotaxonomic data support the conclusion that strain YIM 75728T represents a novel species of a novel genus of the family Pseudonocardiaceae for which the name Actinorectispora indica gen. nov., sp. nov., is proposed. Strain YIM 75728T ( = DSM 45410T = CCTCC AA 209065T) is the type strain of Actinorectispora indica. Strain YIM 75728T was considered as the type strain over the other two strains based on the highest sequence read length of the strain.

Nonomuraea indica sp. nov., novel actinomycetes isolated from lime-stone open pit mine, India.

A Gram-positive, aerobic, nonmotile actinomycete strain designated DRQ-2(T) was isolated from the soil sample collected from lime-stone open pit mine from the Gulbarga region, Karnataka province, India. Strain DRQ-2(T) was identified as a member of the genus Nonomuraea by a polyphasic approach. Strain DRQ-2(T) could be differentiated from other members of the genus Nonomuraea on the basis of physiology and 16S rRNA gene sequence analysis. The 16S rRNA gene sequence similarity of strain DRQ-2(T) showed highest sequence similarity to Nonomuraea muscovyensis DSM 45913(T) (99.1%), N. salmonea DSM 43678(T) (98.2%) and N. maheshkhaliensis JCM 13929(T) with 98.0%, respectively. Chemotaxonomic properties showing predominant menaquinones of MK-9 (H4), MK-9(H2) and MK-9(H6), major polar lipids comprised diphosphatidylglycerol, phosphatidylmono methyl ethanolamine (PME), phosphatidylethanolamine (PE), hydroxy-PME (OH-PME), hydroxy PE (OH-PEE), phosphatidylglycerol (PG), ninhydrin-positive phosphoglycolipid and unknown phospholipid, fatty acids with major amounts of i-C16:0, ai-C15:0 and ai-C17:0 supported allocation of the strain to the genus Nonomuraea. Results of DNA-DNA hybridization and physiological tests allowed genotypic and phenotypic differentiation of strain DRQ-2(T) from closely related species. The genomic DNA G+C content of the organism was 72.5 mol%. On the basis of phenotypic, chemotypic and molecular characteristics, strain DRQ-2(T) represents a novel species of the genus Nonomuraea, for which the name N. indica sp. nov. is proposed, with type strain DRQ-2(T) (=NCIM 5480(T)= CCTCC AA 209050(T)).

Sinomonas mesophila sp. nov., isolated from ancient fort soil.

A moderate growing strain designated as MPKL 26(T) was isolated from a soil sample of Bidar Fort, Karnataka, India. The strain MPKL 26(T) was Gram positive, bent rod in shape. The optimum pH and temperature for growth was 7.0 and 30 °C, respectively. The 16S ribosomal RNA gene sequence analysis revealed that strain MPKL 26(T) was closely related to S. atrocyanea DSM 20127(T) (98.09%), S. flava CW 108(T) (98.04%), S. soli CW 59(T) (97.99%) and S. notoginsengisoli SYP-B575(T) (97.0%) and showed DNA-DNA hybridization relatedness (46.05±1.2, 33.56±2.55, 32.56±1.7 and 26.79±2.5, respectively, between these strains) less than the threshold value for the delineation of genomic species. The peptidoglycon type was A3α type with glycine, alanine, lysine and glutamic acid as the amino acids. The whole-cell sugars were fructose, ribose, mannose, glucose and galactose. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol along with three unknown polar lipids. The fatty acid profile contained C14:0, C16:0, iso-C14:0, iso-C15:0, iso-C16:0, iso-C17:0, anteiso-C15:0, anteiso-C17:0 and summed feature 4 (17:1 iso I/anteiso B). The predominant respiratory quinine was MK-9(H2) with MK-10(H2), MK-8(H2) and MK-8(H4) as minor respiratory quinines. The G+C content of the genomic DNA was 68.8 mol%. On the basis of phenotypic, chemotaxonomic and molecular characteristics, the strain MPKL 26(T) represents a novel species of the genus Sinomonas, for which the name Sinomonas mesophila sp. nov. is proposed with MPKL 26(T) as the type strain (=NCIM 5552(T)= JCM 30094(T)).