Isoptericola halotolerans sp. nov., a novel actinobacterium isolated from saline soil from Qinghai Province, north-west China

Assessing hydrocarbon degradation capacity of Isoptericola peretonis sp. nov. and related species: a comparative study

Since the beginning of their production and use, fossil fuels have affected ecosystems, causing significant damage to their biodiversity. Bacterial bioremediation can provide solutions to this environmental problem. In this study, the new species Isoptericola peretonis sp. nov. 4D.3T has been characterized and compared to other closely related species in terms of hydrocarbon degradation and biosurfactant production by in vitro and in silico analyses. Biosurfactants play an important role in microbial hydrocarbon degradation by emulsifying hydrocarbons and making them accessible to the microbial degradation machinery. The tests performed showed positive results to a greater or lesser degree for all strains. In the synthesis of biosurfactants, all the strains tested showed biosurfactant activity in three complementary assays (CTAB, hemolysis and E24%) and rhamnolipid synthesis genes have been predicted in silico in the majority of Isoptericola strains. Regarding hydrocarbon degradation, all the Isoptericola strains analyzed presented putative genes responsible for the aerobic and anaerobic degradation of aromatic and alkane hydrocarbons. Overall, our results highlight the metabolic diversity and the biochemical robustness of the Isoptericola genus which is proposed to be of interest in the field of hydrocarbon bioremediation.

Isoptericola luteus sp. nov., a novel yellow bacterium isolated from soil

An aerobic, non-motile, Gram-stain-positive bacterium, designated strain NEAU-Y5T, was isolated from a soil sample collected from Northeast Agricultural University, Heilongjiang province. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-Y5T belonged to the genus and showed high 16S rRNA sequence similarity to Isoptericola variabilis (98.9 %), Isoptericola nanjingensis (98.9 %), Isoptericola cucumis (98.5 %), Isoptericola hypogeus (98.5 %), Isoptericola dokdonensis (98.5 %), Isoptericola jiangsuensis (98.3 %), and Isoptericola halalbus (98.1 %), followed by other members of the genus Isoptericola (<98 %), and phylogenetically clustered with I. dokdonensis and I. jiangsuensis. Strain NEAU-Y5T was found to grow at 4-40 °C (optimum, 28 °C), pH 6.0-12.0 (optimum, pH 7.0), and tolerated 0-6 % NaCl (w/v). The cell-wall peptidoglycan type was l-Lys-d-Asp. The whole-cell hydrolysates contained glucose, galactose, and ribose. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside, and glucosamine unknown phospholipid. Major fatty acids were anteiso-C15 : 0 and anteiso-C17 : 0. The predominant menaquinone was MK-9(H4). The DNA G+C content was 73.4 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between strain NEAU-Y5T and the type strains of the genus Isoptericola ranged from 18.6 to 23.5 % and from 77.3 to 81.6 %, respectively. Based on morphological, physiological, chemotaxonomic, and phylogenetic data, as well as digital DNA-DNA hybridization and average nucleotide identity values, the novel strain NEAU-Y5T could be differentiated from its closest relatives. Therefore, the strain represents a novel species of the genus Isoptericola, for which the name Isoptericola luteus sp. nov. is proposed. The type strain is NEAU-Y5T (=CCTCC AA 2019087T=DSM 110637T).

Molecular characterization and phylogenetic diversity of actinomycetota species isolated from Lake Natron sediments at Arusha, Tanzania

Soda lakes are naturally occurring ecosystems characterized by extreme environmental conditions especially high pH and salinity levels but harboring valuable microbial communities with medical and biotechnological potentials. Lake Natron is one of the soda lakes situated in eastern branch of the East African Gregory Rift valley, Tanzania. In this study, the taxonomy and phylogenetic diversity of Actinomycetota species were explored in Lake Natron using molecular techniques. The sequencing of their 16S rRNA gene resulted into 13 genera of phylum Actinomycetota namely Streptomyces, Microbacterium, Nocardiopsis, Gordonia, Dietzia, Micromonospora, Microcella, Pseudarthrobacter, Nocardioides, Actinotalea, Cellulomonas, Isoptericola, and Glutamicibacter. We describe for the first time, the isolation of Streptomyces lasalocidi, S. harbinensis, S. anthocyanicus, Microbacterium aureliae, Pseudarthrobacter sp., Nocardioides sp. and Glutamicibacter mishrai from soda lake habitats. It also reports for the first time, the isolation of Gordonia spp., Microcella sp. and Actinotalea sp. from an East African Soda Lake as well as isolation of S. pseudogriseolus, S. calidiresistens and Micromonospora spp. from a Tanzania soda lake. Furthermore, two putative novel species of the phylum Actinomycetota were identified. Given that Actinomycetota are known potential sources of important biotechnological compounds, we recommend the broadening of the scope of bioprospection in future to include the novel species from Lake Natron.

Isoptericola croceus sp. nov., a novel actinobacterium isolated from saline-alkali soil

A novel actinomycete, designated strain q2^T, was isolated from the saline-alkaline soil, collected from Daqing, Heilongjiang province, China. The results of phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain q2^T belongs to the genus Isoptericola, and showed the highest sequence similarity to Isoptericola halotolerans KCTC 19046^T (98.48%) and Isoptericola chiayiensis KCTC 19740^T (98.13%), respectively. The average nucleotide identity values between strain q2^T and other members of the genus Isoptericola were lower than 95% recommended for distinguishing novel prokaryotic species. Cells of strain q2^T were Gram-staining-positive, aerobic, non-motile, rod-shaped and non-spore-forming. Colonies of strain q2^T were golden-yellow pigmented, tidy edged and smooth surfaced. Growth occurred at 15-37 °C (optimum, 29 °C), pH 7.0-10.0 (optimum, pH 8.0). The predominant respiratory quinones were MK-9(H₄) and MK-9(H₂). The main detected polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannoside. The peptidoglycan compositions were L-alanine, D-aspartic, L-glutamic acid and L-lysine (type A4α). The major cellular fatty acids (> 10%) were anteiso-C_15:0, iso-C_15:0, and anteiso-C_17:0. The G+C content of the genomic DNA was determined to be 69.7%. Based on the phenotypic, physiological, genotypic, and phylogenetic data, strain q2^T represents a novel species of the genus Isoptericola, for which the name Isoptericola croceus sp. nov. is proposed. The type strain is q2^T (= GDMCC 1.2923^T = KCTC 49759^T).

Bioprospecting for Novel Bacterial Sources of Hydrolytic Enzymes and Antimicrobials in the Romanian Littoral Zone of the Black Sea

Marine microorganisms have evolved a large variety of metabolites and biochemical processes, providing great opportunities for biotechnologies. In the search for new hydrolytic enzymes and antimicrobial compounds with enhanced characteristics, the current study explored the diversity of cultured and uncultured marine bacteria in Black Sea water from two locations along the Romanian coastline. Microbial cell density in the investigated samples varied between 65 and 12.7 × 10³ CFU·mL^-1. The total bacterial community identified by Illumina sequencing of 16S rRNA gene comprised 185 genera belonging to 46 classes, mainly Gammaproteobacteria, Alphaproteobacteria, Flavobacteriia, and 24 phyla. The 66 bacterial strains isolated on seawater-based culture media belonged to 33 genera and showed variable growth temperatures, growth rates, and salt tolerance. A great fraction of these strains, including Pseudoalteromonas and Flavobacterium species, produced extracellular proteases, lipases, and carbohydrases, while two strains belonging to the genera Aquimarina and Streptomyces exhibited antimicrobial activity against human pathogenic bacteria. This study led to a broader view on the diversity of microbial communities in the Black Sea, and provided new marine strains with hydrolytic and antimicrobial capabilities that may be exploited in industrial and pharmaceutical applications.

Genome information of the cellulolytic soil actinobacterium Isoptericola dokdonensis DS-3 and comparative genomic analysis of the genus Isoptericola

The actinobacterial group is regarded as a reservoir of biologically active natural products and hydrolytic enzymes with the potential for biomedical and industrial applications. Here, we present the complete genome sequence of Isoptericola dokdonensis DS-3 isolated from soil in Dokdo, small islets in the East Sea of Korea. This actinomycete harbors a large number of genes encoding carbohydrate-degrading enzymes, and its activity to degrade carboxymethyl cellulose into glucose was experimentally evaluated. Since the genus Isoptericola was proposed after reclassification based on phylogenetic analysis, strains of Isoptericola have been continuously isolated from diverse environments and the importance of this genus in the ecosystem has been suggested by recent culturomic or metagenomic studies. The phylogenic relationships of the genus tended to be closer among strains that had been isolated from similar habitats. By analyzing the properties of published genome sequences of seven defined species in the genus, a large number of genes for carbohydrate hydrolysis and utilization, as well as several biosynthetic gene clusters for secondary metabolites, were identified. Genomic information of I. dokdonensis DS-3 together with comparative analysis of the genomes of Isoptericola provides insights into understanding this actinobacterial group with a potential for industrial applications.

From ecophysiology to cultivation methodology: filling the knowledge gap between uncultured and cultured microbes

Earth is dominated by a myriad of microbial communities, but the majority fails to grow under in situ laboratory conditions. The basic cause of unculturability is that bacteria dominantly occur as biofilms in natural environments. Earlier improvements in the culture techniques are mostly done by optimizing media components. However, with technological advancement particularly in the field of genome sequencing and cell imagining techniques, new tools have become available to understand the ecophysiology of microbial communities. Hence, it becomes easier to mimic environmental conditions in the culture plate. Other methods include co-culturing, emendation of growth factors, and cultivation after physical cell sorting. Most recently, techniques have been proposed for bacterial cultivation by employing genomic data to understand either microbial interactions (network-directed targeted bacterial isolation) or ecosystem engineering (reverse genomics). Hopefully, these techniques may be applied to almost all environmental samples, and help fill the gaps between the cultured and uncultured microbial communities.

Isoptericola halalbus sp. nov., a halotolerant actinobacterium isolated from saline lake sediment

A novel Gram-stain-positive bacterium, designated CFH 91151^T, was isolated from sediment collected from a saline lake in Yuncheng, Shanxi Province, PR China. Cells of strain CFH 91151^T were rod-or v-shaped, aerobic, non-motile, non-spore-forming and halotolerant. Results of 16S rRNA gene sequence analysis revealed that strain CFH 91151^T was closely related to Isoptericola variabilis MX5^T and Isoptericola nanjingensis H17^T (98.7 and 98.4% sequence similarity, respectively). The strain grew at 4-45 °C, pH 5.0-9.0 and with 0-14.0 % (w/v) NaCl. Cells were positive for catalase, nitrate was not used and H₂S was not produced. Major cellular fatty acids were anteiso-C_15 : 0 (62.76 %), anteiso-C_17 : 0 (12.09 %) and iso-C_15 : 0 (9.46 %). The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two unidentified phospholipids and three unidentified glycolipids. The menaquinone was MK-9 (H4). The genome size was 4.10 Mbp with a G+C content of 72.4 mol%. The average amino acid identity (ANI) and in silico DNA-DNA hybridization (DDH) values between CFH 91151^T and the other species of the genus Isoptericola were found to be low (ANIm <87.19 %, ANIb <84.38 % and DDH <29.30 %). Based on physiological properties, chemotaxonomic characteristics and low ANI and DDH results, strain CFH 91151^T is considered to represent a novel species, for which the name Isoptericola halalbus sp. nov. is proposed. The type strain is CFH 91151^T (=DSM 105976^T=KCTC 49061^T).

Characterization of a thermostable endoglucanase produced by Isoptericola variabilis sp. IDAH9

This study aimed to isolate and evaluate the cellulase activity of cellulolytic bacteria in hot springs of Dehloran, Ilam province, Iran. Water and sludge samples were collected from the hot springs and the bacterial enrichment was performed in a medium containing rice barn and carboxymethyl cellulose (CMC). The cultures were incubated at 50 °C in aerobic conditions. The bacteria were isolated on CMC agar (1%) medium. Cellulase assay of the isolates was measured by the evaluation of endoglucanase enzyme activity, which is also called as carboxymethyl cellulase (CMCase). The isolated thermotolerant bacteria were then identified and optimized for the production of CMCase. Moreover, stabilizing elements of the enzyme were identified with in silico approach. The chosen isolate was identified as Isoptericola variabilis sp. IDAH9. The identified strain produced the most thermostable CMCase at a concentration of 5.6 g/L of ammonium sulfate, 9 g/L CMCase or 12 g/L rice bran, 0/6% Tween-80, and 0.2% sucrose. The produced enzyme showed 80% of the residual activity after 1 h of incubation at 65 °C. In silico data indicated that the remaining residual activity was due to the redundant stabilizing elements in the protein structure. Consequently, I. variabilis can be isolated from the extreme environment and has a thermostable endoglucanase which may be used for various applications after studying them.

Isoptericola cucumis sp. nov., isolated from the root tissue of cucumber (Cucumis sativus)

A Gram-stain-positive, aerobic organism, showing an irregular cell morphology, was isolated from the root tissue of cucumber (Cucumis sativus) and investigated in detail for its taxonomic position. On the basis of the 16S rRNA gene sequence analysis, strain AP-38T was shown to be most closely related to Isoptericola variabilis (99.1 %) and Isoptericola nanjingensis (98.9 %). The 16S rRNA gene sequence similarity to all other species of the genus Isoptericola was ≤98.5 %. DNA-DNA relatedness to Isoptericola variablis DSM 10177T and Isoptericola nanjingensis DSM 24300T was 31(reciprocal 41 %) and 34 (reciprocal 34 %), respectively. The diagnostic diamino acid of the peptidoglycan was l-lysine. The quinone system contained predominantly menaquinones MK-9(H4) and MK-9(H2). In the polar lipid profile, major compounds were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two phosphatidylinositol mannosides. The polyamine pattern contained the major components spermidine and spermine and significant amounts of tyramine. In the fatty acid profile, anteiso-C15 : 0 and iso-C15 : 0 were present in major amounts. These data support the allocation of the strain to the genus Isoptericola. The results of physiological and biochemical characterization additionally provide phenotypic differentiation of strain AP-38T from I. variabilis and I. nanjingensis. AP-38T represents a novel species of the genus Isoptericola, for which we propose the name Isoptericola cucumis sp. nov., with AP-38T (= LMG 29223T=CCM 8653T) as the type strain.

Antimicrobial biosynthetic potential and genetic diversity of endophytic actinomycetes associated with medicinal plants

Endophytic actinomycetes are one of the primary groups that share symbiotic relationships with medicinal plants and are key reservoir of biologically active compounds. In this study, six selective medicinal plants were targeted for the first time for endophytic actinomycetes isolation from Gibbon Wild Life Sanctuary, Assam, India, during winter and summer and 76 isolates were obtained. The isolates were found to be prevalent in roots followed by stem and leaves. 16S rRNA gene sequence analysis revealed 16 genera, including rare genera, Verrucosispora, Isoptericola and Kytococcus, which have never been previously reported as endophytic. The genus Streptomyces (66%) was dominant in both seasons. Shannon's diversity index showed that Azadirachta indica (1.49), Rauwolfia serpentina (1.43) and Emblica officinalis (1.24) were relatively good habitat for endophytic actinomycetes. Antimicrobial strains showed prevalence of polyketide synthase (PKS) type-II (85%) followed by PKS type-I (14%) encoded in the genomes. Expression studies showed 12-fold upregulation of PKSII gene in seventh day of incubation for Streptomyces antibioticus (EAAG90). Our results emphasize that the actinomycetes assemblages within plant tissue exhibited biosynthetic systems encoding for important biologically active compounds.

A novel marine bacterium Isoptericola sp. JS-C42 with the ability to saccharifying the plant biomasses for the aid in cellulosic ethanol production

The ever growing demands for food products such as starch and sugar produces; there is a need to find the sources for saccharification for cellulosic bioethanol production. This study provides the first evidence of the lignocellulolytic and saccharifying ability of a marine bacterium namely Isoptericola sp. JS-C42, a Gram positive actinobacterium with the cocci cells embedded on mycelia isolated from the Arabian Sea, India. It exhibited highest filter paper unit effect, endoglucanase, exoglucanase, cellobiohydrolase, β-glucosidase, xylanase and ligninase effect. The hydrolytic potential of the enzymes displayed the efficient saccharification capability of steam pretreated biomass. It was also found to degrade the paddy, sorghum, Acacia mangium and Ficus religiosa into simple reducing sugars by its efficient lignocellulose enzyme complex with limited consumption of sugars. Production of ethanol was also achieved with the Saccharomyces cerevisiae. Overall, it offers a great potential for the cellulosic ethanol production in an economically reliable and eco-friendly point-of-care.

Isoptericola chiayiensis sp. nov., isolated from mangrove soil

A novel actinomycete, designated strain 06182M-1T, was isolated from a mangrove soil sample collected from Chiayi County in Taiwan. Phylogenetic analysis based on 16S rRNA gene sequences revealed levels of similarity of 97.0–98.8 % to the type strains of recognized species of the genus Isoptericola. Chemotaxonomic data also supported the placement of strain 06182M-1T within the genus Isoptericola. However, the low levels of DNA–DNA relatedness between the novel strain and the type strains of recognized species of the genus Isoptericola, in combination with differential phenotypic data, demonstrate that strain 06182M-1T represents a novel species of the genus Isoptericola, for which the name Isoptericola chiayiensis sp. nov. is proposed. The type strain is 06182M-1T ( = BCRC 16888T  = KCTC 19740T).

Isoptericola nanjingensis sp. nov., a mineral-weathering bacterium

A Gram-positive-staining, non-motile, rod- or coccoid-shaped actinobacterium, designated strain H17T, was isolated from a soil sample from Nanjing, Jiangsu Province, PR China. The organism grew optimally at 30 °C, pH 7.0 and with 3 % NaCl (w/v). Strain H17T contained L-Lys-D-Asp as the cell-wall peptidoglycan type and galactose, xylose and mannose as the whole-cell sugars. The major fatty acids were anteiso-C15:0 and iso-C15:0. The total polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipids, phosphatidylinositol, phosphoglycolipid, one unidentified glycolipid and one unidentified lipid. The menaquinone was MK9(H4). Mycolic acids were not detected. The DNA G+C content was 72.4 mol%. Phylogenetic analysis of this strain based on 16S rRNA gene sequences revealed 97.8-99.6 % similarity to recognized species of the genus Isoptericola. The low level of DNA-DNA relatedness to other species of the genus Isoptericola and the many phenotypic properties that distinguished strain H17T from recognized species of this genus demonstrated that isolate H17T should be classified as representing a novel species of the genus Isoptericola. The name Isoptericola nanjingensis sp. nov. is proposed for this novel species. The type strain is H17T (=DSM 24300T=CCTCC AB 2011005T).

Koreibacter algae gen. nov., sp. nov., isolated from seaweed

A Gram-positive, aerobic, non-motile, rod-shaped actinomycete, designated strain DSW-2T, was isolated from a seaweed sample collected around Mara Island, Jeju, Republic of Korea. Comparative 16S rRNA gene sequence analysis showed that strain DSW-2T belongs to the suborder Micrococcineae and forms a distinct clade separated from representatives of the several families of this order. Levels of 16S rRNA gene sequence similarity between the novel strain and members of this suborder were lower than 96.4 %. The peptidoglycan type is A3α with Lys–Ser as the interpeptide bridge. Whole-cell sugars are glucose and galactose. The major menaquinone is MK-9(H4). The predominant fatty acid is ai-C15 : 0. The polar lipids are phosphatidylglycerol and phosphatidylinositol. The DNA G+C content was 68.3 mol%. On the basis of the chemotaxonomic markers and phylogenetic distinctiveness presented here, it is evident that the isolate represents a novel taxon within the suborder Micrococcineae. The name Koreibacter algae gen. nov., sp. nov. is proposed, with the type strain DSW-2T (=KCTC 13436T =DSM 22126T).

Diversity of culturable actinobacteria from Qinghai-Tibet plateau, China

To investigate the diversity of culturable actinobacteria and further screen for microbial pharmaceutics, seven different media were chosen to isolate actinobacteria from 87 soil samples collected from Qinghai-Tibet plateau. A total of 1930 strains was isolated and identified to belong to 11 suborders, i.e., Actinopolysporineae, Corynebacterineae, Frankineae, Glycomycineae, Kineosporiineae, Micrococcineae, Micromonosporineae, Propionibacterineae, Pseudonocardineae, Streptomycineae and Streptosporangineae, and 16 families, i.e., Nocardioidaceae, Actinopolysporaceae, Actinosynnemataceae, Dermacoccaceae, Geodermatophilaceae, Glycomycetaceae, Kineosporiaceae, Microbacteriaceae, Micromonosporaceae, Nocardiaceae, Promicromonosporaceae, Propionibacteriaceae, Pseudonocardiaceae, Streptomycetaceae, Streptosporangiaceae and Thermomonosporaceae. A primary taxonomic study showed that at least 22 genera of actinobacteria were identified from the soil samples, among which ten isolates represented hitherto unknown species. The results showed that there was abundant actinobacterial species diversity in the soil samples from the Qinghai-Tibet plateau.

Isoptericola jiangsuensis sp. nov., a chitin-degrading bacterium

A Gram-positive-staining, non-motile, rod- or coccoid-shaped bacterium, strain CLGT, was isolated from beach sand from Lianyungang, Jiangsu Province, PR China. The organism grew optimally at 30 °C and pH 7.0. Strain CLGT contained l-Lys–d-Asp as the peptidoglycan type and galactose, rhamnose and xylose as the whole-cell sugars. It contained anteiso-C15 : 0 and iso-C15 : 0 as the major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phospholipid, phosphatidylinositol, three phosphoglycolipids and one unidentified lipid. The DNA G+C content was 70.3 mol%. The 16S rRNA gene sequence similarity of strain CLGT with Isoptericola dokdonensis DS-3T was 99.4 % but the DNA–DNA relatedness between strain CLGT and I. dokdonensis DS-3T was 58.7 %. There were also many phenotypic properties that distinguished strain CLGT from recognized species of the genus Isoptericola. The results showed that strain CLGT represents a novel species of the genus Isoptericola, for which the name Isoptericola jiangsuensis sp. nov. is proposed. The type strain is CLGT (=DSM 21863T=CCTCC AB208287T).

Nocardiopsis quinghaiensis sp. nov., isolated from saline soil in China

A previously unknown Gram-positive, obligately aerobic actinomycete, YIM 28A4(T), was isolated from a sample of saline soil collected from the Qaidam Basin in Qinghai Province, north-west China, and was investigated using a polyphasic taxonomic approach. The strain grew well on most of the media tested, producing white to pale-yellow substrate mycelium, white aerial mycelium and straight to flexuous hyphae. The substrate mycelium was well developed and fragmented with age; the aerial mycelium produced long, straight spore chains. The spore chains were composed of non-motile, smooth-surfaced, rod-shaped spores. No diffusible pigments were produced on any of the media tested. The strain grew in the presence of 0-10 % (w/v) NaCl and at pH 6.0-8.0, with optimum growth occurring at 3 % (w/v) NaCl and pH 7.0. It grew at 10-37 degrees C, the optimum growth temperature being 28 degrees C. Whole-cell hydrolysates of strain YIM 28A4(T) contained meso-diaminopimelic acid and no diagnostic sugars. The predominant phospholipids were phosphatidylcholine, phosphatidylglycerol and diphosphatidylglycerol. The predominant menaquinones were MK-10, MK-10(H(2)), MK-11 and MK-11(H(2)). The major cellular fatty acids were iso-C(16 : 0), anteiso-C(15 : 0) and anteiso-C(17 : 0). The DNA G+C content was 67.1 mol%. The morphological and chemotaxonomic characteristics of the isolate matched those described for Nocardiopsis species. A phylogenetic analysis based on 16S rRNA gene sequence comparisons confirmed that strain YIM 28A4(T) was a member of the genus Nocardiopsis and most closely related to the type strains Nocardiopsis aegyptia DSM 44442(T) and Nocardiopsis halotolerans DSM 44410(T), showing 98.1 and 97.8 % 16S rRNA gene sequence similarity, respectively. Strain YIM 28A4(T) can be differentiated from these type strains by using phenotypic, phylogenetic and DNA-DNA hybridization data. On the basis of the polyphasic evidence, strain YIM 28A4(T) represents a novel species of the genus Nocardiopsis, for which the name Nocardiopsis quinghaiensis sp. nov. is proposed. The type strain is YIM 28A4(T) (=DSM 44739(T) =CGMCC 4.3494(T)).

Salinicoccus salitudinis sp. nov., a new moderately halophilic bacterium isolated from a saline soil sample

A novel pale-yellow-pigmented, moderately halophilic, facultatively alkaliphilic, non-motile, non-spore-forming, catalase- and oxidase-positive, obligately aerobic Gram-positive coccus, strain YIM-C678T was isolated from a saline soil sample collected from a hypersaline habitat in the Qaidam basin, northwest China. The organism grew at 4-37 degrees C and pH 6.0-11.0, with optimum growth at 25 degrees C and pH 8.0. Strain YIM-C678T grew optimally in the presence of 10-12% (w/v) NaCl and growth was observed in 1-25% (w/v) NaCl. The cell wall murein type was L: -Lys-Gly5. Major cellular fatty acids were anteiso-C15:0, iso-C15:0, iso-C16:0 and C16:0. Menaquinone 6 (MK-6) was the major respiratory quinone. The DNA G + C content was 46.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain YIM-C678T belonged to the family Staphylococcaceae and was most closely related to the eight described species of the genus Salinicoccus with sequence similarities from 92.2 (S. luteus YIM 70202T) to 97.5% (S. kunmingensis YIM Y15T). The DNA-DNA relatedness between strain YIM-C678T and S. kunmingensis YIM Y15T was 35.4%. Chemotaxonomic data and 16S rRNA gene sequence analysis supported the affiliation of strain YIM-C678T with the genus Salinicoccus. The combination of phylogenetic analysis, phenotypic characteristics, chemotaxonomic differences and DNA-DNA hybridization data supported the view that the bacterium represents a novel species of the genus Salinicoccus, for which the name Salinicoccus salitudinis sp. nov. is proposed, with YIM-C678T (=DSM 17846 = CGMCC 1.6299) as the type strain.

Demequina aestuarii gen. nov., sp. nov., a novel actinomycete of the suborder Micrococcineae, and reclassification of Cellulomonas fermentans Bagnara et al. 1985 as Actinotalea fermentans gen. nov., comb. nov

An actinobacterial strain containing demethylmenaquinone DMK-9(H4) as the diagnostic isoprenoid quinone was isolated from a tidal flat sediment sample, from South Korea. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain JC2054T represents a distinct phyletic line within the suborder Micrococcineae of the order Actinomycetales. The closest phylogenetic neighbour was Cellulomonas fermentans, with 94.7 % 16S rRNA gene sequence similarity. The novel isolate was strictly aerobic and slightly halophilic, with optimum growth occurring in 2–4 % (w/v) NaCl. Cells were non-motile, non-sporulating and rod-shaped. The peptidoglycan type was of the A-type of cross-linkage. l-ornithine was the diamino acid and d-glutamate represented the N-terminus of the interpeptide bridge. The predominant fatty acids were anteiso-branched and straight-chain fatty acids. The major polar lipids were phosphatidylinositol, diphosphatidylglycerol and an unknown phospholipid. The menaquinone composition of C. fermentans was determined to be MK-10(H4), MK-9(H4) and MK-8(H4) in the ratio 56 : 2 : 1. On the basis of the polyphasic evidence presented in this study, it is proposed that strain JC2054T should be classified as representing a novel genus and species of the suborder Micrococcineae, with the name Demequina aestuarii gen. nov., sp. nov. The type strain is JC2054T (=IMSNU 14027T=KCTC 9919T=JCM 12123T). In addition, it was clear from the phylogenetic analysis and chemotaxonomic data that C. fermentans does not belong to the genus Cellulomonas or any other recognized genera. Therefore, C. fermentans should be reclassified as representing a novel genus, for which the name Actinotalea fermentans gen. nov., comb. nov. is proposed, with strain DSM 3133T (=ATCC 43279T=CFBP 4259T=CIP 103003T=NBRC 15517T=JCM 9966T=LMG 16154T) as the type strain.

Isoptericola dokdonensis sp. nov., isolated from soil

A Gram-positive, non-motile, rod- or coccoid-shaped Isoptericola-like bacterium, strain DS-3T, was isolated from a soil sample from Dokdo, Korea, and its taxonomic position was investigated by a polyphasic approach. The organism grew optimally at 30 °C and pH 7.0–8.0. Strain DS-3T had the peptidoglycan type based on l-lys–d-Asp, and galactose, glucose, rhamnose and ribose as the whole-cell sugars. It contained MK-9(H4) as the predominant menaquinone and anteiso-C15 : 0 and iso-C15 : 0 as the major fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and two unidentified glycolipids. The DNA G+C content was 74.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DS-3T was most closely related to members of the genus Isoptericola. Similarity values between the 16S rRNA gene sequences of strain DS-3T and the type strains of Isoptericola species ranged from 98.0 to 98.4 %. DNA–DNA relatedness values (11–23 %) and differential phenotypic properties demonstrated that strain DS-3T was distinguishable from recognized Isoptericola species. On the basis of phenotypic properties and phylogenetic and genetic distinctiveness, strain DS-3T represents a novel species in the genus Isoptericola, for which the name Isoptericola dokdonensis sp. nov. is proposed. The type strain is DS-3T (=KCTC 19128T=CIP 108921T).

Sinococcus qinghaiensis gen. nov., sp. nov., a novel member of the order Bacillales from a saline soil in China

A Gram-positive, non-spore-forming isolate, designated YIM 70212T, was isolated from a hypersaline soil sample collected from Qinghai, north-west China. Cells of the isolate were orange-pigmented, motile cocci with multiple flagella. A polyphasic taxonomic investigation was carried out on the isolate. The organism grew at 10–45 °C and pH 7.5–11.0, with optimum growth at 28 °C and pH 8.0–9.5. Strain YIM 70212T grew optimally in the presence of 10 % NaCl, KCl or MgCl2.6H2O and growth was observed in 1–25 % NaCl, KCl or MgCl2.6H2O. The peptidoglycan type was A1γ. Ribose and minor amounts of galactose were detected as the whole-cell sugars. MK-5 was the only menaquinone. The major cellular fatty acids were ai-C15 : 0 (52.4 %) and ai-C17 : 0 (26.5 %). The DNA G+C content was 47.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain YIM 70212T formed a distinct lineage within the order Bacillales and was most closely related to members of the genus Marinococcus, showing 16S rRNA gene sequence similarity levels of 91.0–91.4 %. Based on the high 16S rRNA gene sequence divergence and differences in phenotypic characteristics, it is proposed that the unknown strain be classified in a novel genus and species with the name Sinococcus qinghaiensis gen. nov., sp. nov.; the type strain of Sinococcus qinghaiensis is YIM 70212T (=KCTC 3943T=DSM 17008T).