G. S. N. Reddy

Arthrobacter flavus sp. nov., a psychrophilic bacterium isolated from a pond in McMurdo Dry Valley, Antarctica

CMS 19YT, a psychrophilic bacterium, was isolated from a cyanobacterial mat sample from a pond in Antarctica and was characterized taxonomically. The bacterium was aerobic, gram-positive, non-spore-forming, non-motile, exhibited a rod-coccus growth cycle and produced a yellow pigment that was insoluble in water but soluble in methanol. No growth factors were required and it was able to grow between 5 and 30 degrees C, between pH 6 and pH 9 and tolerated up to 11.5% NaCl. The cell wall peptidoglycan was Lys-Thr-Ala3 (the A3alpha variant) and the major menaquinone was MK-9(H2). The G+C content of the DNA was 64+/-2 mol%. The 16S rDNA analysis indicated that CMS 19YT is closely related to group I Arthrobacter species and showed highest sequence similarity (97.91%) with Arthrobacter agilis. Furthermore, DNA-DNA. hybridization studies also indicated 77% homology between CMS 19YT and A. agilis. It differed from A. agilis, however, in that it was psychrophilic, non-motile, yellow in colour, exhibited a rod-coccus growth cycle, had a higher degree of tolerance to NaCl and was oxidase- and urease-negative and lipase-positive. In addition, it had a distinct fatty acid composition compared to that of A. agilis: the predominant fatty acids were C15:0, anteiso-C15:0, C16:0, iso-C16:0, C17:0, anteiso-C17:0 and C18:0. It is proposed, therefore, that CMS 19YT should be placed in the genus Arthrobacter as a new species, i.e. Arthrobacter flavus sp. nov. The type strain of A. flavus is CMS 19YT (= MTCC 3476T).

Planococcus antarcticus and Planococcus psychrophilus spp. nov. isolated from cyanobacterial mat samples collected from ponds in Antarctica

Abstract. Thirteen orange-pigmented bacteria associated with cyanobacterial mat samples collected from four different lakes in McMurdo, Antarctica, were isolated. Twelve of the isolates, which were coccoid in shape, were very similar and possessed all the characteristics of the genus Planococcus and represented a new species, which was assigned the name Planococcus antarcticus sp. nov. (CMS 26orT). Apart from the phenotypic differences, P. antarcticus differed from all reported species of Planococcus by more than 2.5% at the 16S rRNA gene sequence level. In addition, at the DNA–DNA hybridization level, it exhibited very little similarity either with P. mcmeekinii (30%–35%), P. okeanokoites (26%–29%), or CMS 53orT (15%–25%), the three species with which it is closely related at the rRNA gene sequence level (2.5%–2.9%). P. antarcticus also showed only 2.5% difference in its 16S rRNA gene sequence compared with the P. alkanoclasticus sequence. But it was distinctly different from P. alkanoclasticus, which exists only as rods, is mesophilic and phosphatase positive, can hydrolyze starch, cannot utilize succinate, glutamate, or glucose, and cannot acidify glucose. Most important, P. antarcticus and P. alkanoclasticus varied distinctly in their fatty acid composition in that C15:0, C15:1, C16:0, iso-C16:1, and C17:0 were present only in P. antarcticus but absent in P. alkanoclasticus. CMS 53orT, the thirteenth isolate, was also identified as a new species of Planococcus and was assigned the name Planococcus psychrophilus sp. nov. This species was distinctly different from all the reported species, including the new species P. antarcticus, with respect to a number of phenotypic characteristics. At the 16S rRNA gene sequence level, it was closely related to P. okeanokoites (98.1%) and P. mcmeekinii (98%), but with respect to the DNA–DNA hybridization, the similarity was only 35%–36%. The type strain of P. antarcticus is CMS 26orT (MTCC 3854; DSM 14505), and that of P. psychrophilus is CMS 530rT (MTCC 3812; DSM 14507).

Arthrobacter roseus sp. nov., a psychrophilic bacterium isolated from an Antarctic cyanobacterial mat sample

Strain CMS 90rT, a red-pigmented bacterium, was isolated from a cyanobacterial mat sample from a pond located in McMurdo, Antarctica. Based on its chemotaxonomic and phylogenetic properties, strain CMS 90r(T) was identified as a member of group I of Arthrobacter. It shared 16S rDNA similarity of 98% with Arthrobacter oxydans ATCC 14358T and Arthrobacter polychromogenes ATCC 15216T, while DNA-DNA similarities determined for these three organisms were less than 70%. It also differed from all 17 reported Arthrobacter species with A3alpha-variant peptidoglycan in that it possessed a unique peptidoglycan (Lys-Gly-Ala3) and contained galactose, glucose, ribose and rhamnose as cell-wall sugars. These data and the presence of diagnostic phenotypic traits support the description of CMS 90r(T) as a novel species of Arthrobacter, for which the name Arthrobacter roseus sp. nov. is proposed. The type strain is strain CMS 90r(T) (= MTCC 3712T = DSM 14508T).

Bacterial diversity of soil in the vicinity of Pindari glacier, Himalayan mountain ranges, India, using culturable bacteria and soil 16S rRNA gene clones.

Three 16S rRNA gene clone libraries (P1L, P4L and P8L) were constructed using three soil samples (P1S, P4S and P8S) collected near Pindari glacier, Himalayas. The three libraries yielded a total of 703 clones. Actinobacteria, Firmicutes and Proteobacteria were common to the three libraries. In addition to the above P1L and P8L shared the phyla Acidobacteria, Bacteroidetes, Gemmatimonadetes and Planctomycetes. Phyla Chlamydiae, Chlorobi, Chloroflexi, Dictyoglomi, Fibrobacteres, Nitrospirae, Verrucomicrobia, candidate division SPAM and candidate TM7s TM7a phylum were present only in P1L. Rarefaction analysis indicated that the bacterial diversity in P4S and P8S soil samples was representative of the sample. Principal component analysis (PCA) revealed that P1S and P8S were different from P4S soil sample. PCA also indicated that arsenic content, pH, Cr and altitude influence the observed differences in the percentage of specific OTUs in the three 16S rRNA gene clone libraries. The observed bacterial diversity was similar to that observed for other Himalayan and non-polar cold habitats. A total of 40 strains of bacteria were isolated from the above three soil samples and based on the morphology 20 bacterial strains were selected for further characterization. The 20 bacteria belonged to 12 different genera. All the isolates were psychro-, halo- and alkalitolerant. Amylase and urease activities were detected in majority of the strains but lipase and protease activities were not detected. Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria.

Bacillus cecembensis sp. nov., isolated from the Pindari glacier of the Indian Himalayas

Strain PN5(T) is a Gram-positive, aerobic, motile, rod-shaped, peritrichously flagellated bacterium that was isolated from the Pindari glacier using nutrient agar medium. Cells of PN5(T) are catalase-positive and oxidase-negative and contain lysine, glutamic acid and alanine in the peptidoglycan (peptidoglycan type A4alpha). Further, the cells are characterized by the presence of iso-C(15 : 0) and iso-C(16 : 1) as the predominant fatty acids and MK-7 as the isoprenoid quinone. Based on the above characteristics, strain PN5(T) was assigned to the genus Bacillus. Phylogenetic analysis based on the 16S rRNA gene sequence indicated that strain PN5(T) clustered with the type strain of Bacillus silvestris with a sequence similarity of 97.2 %. DNA-DNA hybridization between PN5(T) and B. silvestris DSM 12223(T) resulted in a relatedness of only 15 %, clearly indicating that strain PN5(T) represents a novel species. Further, PN5(T) was different from B. silvestris with respect to various phenotypic and chemotaxonomic characteristics. Therefore, strain PN5(T) is identified as a representative of a novel species of the genus Bacillus, for which the name Bacillus cecembensis sp. nov. is proposed. Bacillus cecembensis is unique among psychrotolerant Bacillus species in containing l-Lys-d-Glu in the cell-wall peptidoglycan. The type strain is PN5(T) (=LMG 23935(T) =MTCC9127(T) =JCM 15113(T)).

Pseudonocardia antarctica sp. nov. an Actinomycetes from McMurdo Dry Valleys, Antarctica

Strain DVS 5a1 was isolated from a moraine sample from the McMurdo Dry Valleys region of Antarctica. The strain is aerobic, Gram-positive, with white aerial mycelia and brown substrate mycelia, sporulating, has meso-diaminopimelic acid, arabinose and galactose in the cell wall, MK-8 (H4) as the major menaquinone and a mol% G+C content of DNA of 71% thus confirming to the description of the genus Pseudonocardia. Phylogenetic analysis based on the 16S rRNA gene sequence analysis further confirms that DVS 5al which forms a robust clade with P. alni, P. compacta, P. autotrophica and P. kongjuensis is closely related to the genus Pseudonocardia and exhibits maximum similarity of 99.7% with Pseudonocardia alni. However, at whole genome level as determined by DNA-DNA hybridisation DVS 5al exhibits a similarity of only 50% with Pseudonocardia alni. Further, DVS 5al differs from Pseudonocardia alni in that it does not produce acid from D-arabinose, meso-erythritol, melizitose, sorbitol, sucrose, D-trehalose; but produces acid from D-mannitol, D-galactose, D-maltose, D-mannose, inulin, D-ribose and D-xylose. Further, compared to Pseudonocardia alni, it has two additional fatty acids namely Me-C(18:0) and Me-C(19:0) and also possesses one additional unidentified lipid. It also shows distinct differences with P. compacta, P. autotrophica and P. kongjuensis and the other species of Pseudonocardia. It is proposed to assign DVS 5a1 the status of a new species for which the name Pseudonocardia antarctica sp. nov. is suggested.

Comparison of bacterial diversity in proglacial soil from Kafni Glacier, Himalayan Mountain ranges, India, with the bacterial diversity of other glaciers in the world

Two 16S rRNA gene clone libraries (KF and KS) were constructed using two soil samples (K7s and K8s) collected near Kafni Glacier, Himalayas. The two libraries yielded a total of 648 clones. Phyla Actinobacteria, Bacteroidetes, Chloroflexi Firmicutes, Proteobacteria, Spirochaetae, Tenericutes and Verrucomicrobia were common to the two libraries. Phyla Acidobacteria, Chlamydiae and Nitrospirae were present only in KF library, whereas Lentisphaerae and TM7 were detected only in KS. In the two libraries, clones belonging to phyla Bacteroidetes and Proteobacteria were the most predominant. Principal component analysis (PCA) revealed that KF and KS were different and arsenic content influenced the differences in the percentage of OTUs. PCA indicated that high water content in the K8s sample results in high total bacterial count. PCA also indicated that bacterial diversity of KF and KS was similar to soils from the Pindari Glacier, Himalayas; Samoylov Island, Siberia; Schrimacher Oasis, Antarctica and Siberian tundra. The eleven bacterial strains isolated from the above two soil samples were phylogenetically related to six different genera. All the isolates were psychro-, halo- and alkalitolerant. Amylase, lipase and urease activities were detected in the majority of the strains. Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria.

Cryobacterium roopkundense sp. nov., a psychrophilic bacterium isolated from glacial soil

Strain RuGl7(T) was isolated from a soil sample collected at the periphery of the glacial Lake Roopkund in the Himalayan mountain range, India. Cells of RuGl7(T) were Gram-positive, aerobic, rod-shaped, motile and grew optimally between 15 and 18 degrees C. Cells of RuGl7(T) contained 2,4-diaminobutyric acid in the cell-wall peptidoglycan and the major menaquinones were MK-10, MK-11 and MK-12. The polar lipids present were diphosphatidylglycerol and phosphatidylglycerol and an unknown lipid and the major fatty acid was anteiso-C(15 : 0). Based on the above characteristics, strain RuGl7(T) was assigned to the genus Cryobacterium. Strain RuGl7(T) shared a 16S rRNA gene sequence similarity of 97.0 and 99.0 % with Cryobacterium psychrotolerans JCM 13925( T) and Cryobacterium psychrophilum JCM 1463(T), respectively. However, DNA-DNA relatedness values between strain RuGl7(T) and C. psychrotolerans and C. psychrophilum were 28 and 23 %, respectively. Furthermore, strain RuGl7(T) exhibited several phenotypic and genotypic differences when compared with C. psychrotolerans , C. psychrophilum and Cryobacterium mesophilum. Based on these differentiating characteristics, strain RuGl7(T) was identified as a novel species of the genus Cryobacterium for which the name Cryobacterium roopkundense sp. nov. is proposed. The type strain is RuGl7( T) (=DSM 21065(T)=JCM 15131(T)).

Leifsonia pindariensis sp. nov., isolated from the Pindari glacier of the Indian Himalayas, and emended description of the genus Leifsonia

Strain PON10(T) is a yellow-pigmented, Gram-positive, aerobic, motile, rod-shaped bacterium isolated from the Pindari glacier of the Indian Himalayas. The cell-wall peptidoglycan contained DL-diaminobutyric acid as the diamino acid. The predominant fatty acids were anteiso-C(15:0), anteiso-C(17:0) and iso-C(16:0) and the major isoprenoid quinones were MK-10 and MK-11. Based on the above characteristics, strain PON10(T) was assigned to the genus Leifsonia. blast sequence similarity results indicated that Leifsonia ginsengi and Leifsonia poae were the nearest relatives, with 16S rRNA gene sequence similarity of 97.0 and 96.8% to the respective type strains. A difference of 3% in the 16S rRNA gene sequence indicated that PON10(T) represents a novel species of the genus Leifsonia, and therefore DNA-DNA hybridization was not done. In addition, PON10(T) showed a number of differences from Leifsonia ginsengi and Leifsonia poae with respect to phenotypic and chemotaxonomic characteristics. Thus, based on the differences it exhibited from Leifsonia ginsengi and Leifsonia poae, strain PON10(T) was identified as representing a novel species named Leifsonia pindariensis sp. nov. The type strain is PON10(T) (=LMG 24222(T) =MTCC9128(T)). An emended description of the genus Leifsonia is also presented.

Psychrobacter salsus sp. nov. and Psychrobacter adeliensis sp. nov. Isolated from Fast Ice from Adelie Land, Antarctica

Nine psychrotolerant bacteria were isolated from fast ice in the middle of Geologie Archipelago, Adelie Land, Antarctica and were categorized into two groups, based on their SDS-PAGE profiles. Representatives from each of the two groups, namely strains DD 48T and SJ 14T exhibited phenotypic and chemotaxonomic characteristics confirming to the genus Psychrobacter. The 16S rRNA gene sequence indicated that the two isolates are closely related to each other and to the already reported fifteen species of Psychrobacter. Detailed studies on the phenotypic characteristics, chemotaxonomic properties and phylogenetic analysis of strains DD 48T and SJ 14T indicated that they are distinctly different from each other and the reported species of Psychrobacter. At the DNA-DNA hybridisation level, the two species exhibit less than 70% similarity. Thus, strains DD 48T and SJ 14T are identified as new species of the genus Psychrobacter for which the names Psychrobacter salsus sp. nov. and Psychrobacter adeliensis sp. nov. respectively are proposed.