Echinicola vietnamensis sp. nov., a member of the phylum Bacteroidetes isolated from seawater

Genome-Based Classification of Strain 16-SW-7, a Marine Bacterium Capable of Converting B Red Blood Cells, as Pseudoalteromonas distincta and Proposal to Reclassify Pseudoalteromonas paragorgicola as a Later Heterotypic Synonym of Pseudoalteromonas distincta

A strictly aerobic, Gram-stain-negative, rod-shaped, and motile bacterium, designated strain 16-SW-7, isolated from a seawater sample, was investigated in detail due to its ability to produce a unique α-galactosidase converting B red blood cells into the universal type blood cells. The phylogenetic analysis based on 16S rRNA gene sequences revealed that the strain 16-SW-7 is a member of the Gammaproteobacteria genus Pseudoalteromonas. The closest relatives of the environmental isolate were Pseudoalteromonas distincta KMM 638^T and Pseudoalteromonas paragorgicola KMM 3548^T, with the plural paralogous 16S rRNA genes of 99.87-100% similarity. The strain 16-SW-7 grew with 1-10% NaCl and at 4-34°C, and hydrolyzed casein, gelatin, tyrosine, and DNA. The genomic DNA G+C content was 39.3 mol%. The prevalent fatty acids were C_16:1 ω7c, C_16:0, C_17:1 ω8c, C_18:1 ω7c, C_17:0, and C_12:0 3-OH. The polar lipid profile was characterized by the presence of phosphatidylethanolamine, phosphatidylglycerol, two unidentified amino lipids, and three unidentified lipids. The major respiratory quinone was Q-8. The finished genome of the strain 16-SW-7 (GenBank assembly accession number: GCA_005877035.1) has a size of 4,531,445 bp and comprises two circular chromosomes L1 and S1, deposited in the GenBank under the accession numbers CP040558 and CP040559, respectively. The strain 16-SW-7 has the ANI values of 98.2% with KMM 638^T and KMM 3548^T and the DDH values of 84.4 and 83.5%, respectively, indicating clearly that the three strains belonged to a single species. According to phylogenetic evidence and similarity for the chemotaxonomic and genotypic properties, the strain 16-SW-7 (= KCTC 52772 = KMM 701) represents a novel member of the species Pseudoalteromonas distincta. Also, we have proposed to reclassify Pseudoalteromonas paragorgicola as a later heterotypic synonym of P. distincta based on the rules of priority with the emendation of the species.

Comparative genome characterization of Echinicola marina sp. nov., isolated from deep-sea sediment provide insight into carotenoid biosynthetic gene cluster evolution

Echinicola, carotenoid-pigmented bacteria, are isolated from various hypersaline environments. Carotenoid accumulation in response to salt stress can stabilize the cell membrane in order to survive. A pink-colored strain SCS 3-6 was isolated from the deep-sea sediment of the South China Sea. Growth was found to occur at 10-45 °C. The strain could tolerate 10% (w/v) NaCl concentration and grow at pH 5-9. The complete genome of SCS 3-6 comprises 5053 putative genes with a total 5,693,670 bp and an average G + C content of 40.11 mol%. The 16S rRNA gene sequence analysis indicated that strain SCS 3-6 was affiliated with the genus Echinicola, with the closely strains were Echinicola arenosa CAU 1574^T (98.29%)and Echinicola shivajiensis AK12^T (97.98%). For Echinicola species with available genome sequences, pairwise comparisons for average nucleotide identity (ANI) and in silico DNA-DNA hybridization (DDH) revealed ANIb values from 70.77 to 74.71%, ANIm values from 82.72 to 88.88%, and DDH values from 18.00 to 23.40%. To identify their genomic features, we compared their genomes with those of other Echinicola species. Phylogenetic analysis showed that strain SCS 3-6 formed a monophyletic clade. Genomic analysis revealed that strain SCS 3-6 possessed a complete synthetic pathway of carotenoid and speculated that the production was astaxanthin. Based on phenotypic and genotypic analyses in this study, strain SCS 3-6 is considered to represent a novel species of the genus Echinicola for which the name Echinicola marina sp. nov. is proposed. The type strain is SCS 3-6^T (= GDMCC 1.2220^T = JCM 34403^T).

Echinicola arenosa sp. nov., isolated from marine sand

A novel bacterium, designated CAU 1574^T, was isolated from marine sand. Cells were Gram stain negative, aerobic, gliding and rod shaped. Growth was observed at 20-37 °C (optimum, 30 °C), a pH of 5.5-10.0 (optimum, 8.0), and 0-3.0% (w/v) NaCl concentrations (optimum, 1%). Based on the results of 16S rRNA gene sequence analyses, strain CAU 1574^T belonged to the genus Echinicola, and showed the highest similarity to Echinicola shivajiensis JCM 17847^T (97.5%). Phylogenomic analysis based on consisting of 92 core genes extracted from the genome sequences showed that strain CAU 1574^T was affiliated with species in the genus Echinicola. The average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between strain CAU 1574^T and the closely related species were below the cut-off values of 95-96, 90, and 70%, respectively used for species demarcation. The chemotaxonomic data of CAU 1574^T were as follows: major isoprenoid quinone, MK-7; predominant polar lipids, phosphatidylethanolamine, two unidentified aminophospholipids and two unidentified lipids; major fatty acids, iso-C_15:0, summed feature 3 (C_16:1 ω6c/C_16:1 ω7c). The 5.4 Mb genome included 20 contigs and 4237 protein-coding genes with a 39.8 mol% G + C content. Based on the phylogenetic, phenotypic, and physiological result, strain CAU 1574^T represents a novel species of this genus Echinicola, for which the name Echinicola arenosa sp. nov. is proposed. The type strain is CAU 1574^T (= KCTC 82410^T = MCCC 1K05669^T).

Echinicola salinicaeni sp. nov., a novel bacterium isolated from saltern mud

A novel gram-negative, aerobic, pink, motile, gliding, rod-shaped bacterium, designated P51^T, was isolated from saline silt samples in Yantai, China. It was able to grow at 4-42 °C (optimum 33 °C), pH 4.0-9.0 (optimum 7.0), and in 0-11.0% NaCl (optimum 4.0%, w/v). It grew at 4 °C, which was lower than the minimum temperature for related strains. The genome consisted of 4111 genes with a total length of 5 139 782 bp. The 16S rRNA gene sequence analysis indicated that strain P51^T was a member of the genus Echinicola and most closely related to 'Echinicola shivajiensis'. A genome analysis identified genes encoding proteins associated with carbon source utilisation, and the carotenoid biosynthesis and β-lactam resistance pathways. Strain P51^T shared an average nucleotide identity value below 84.7%, an average amino acid identity value between 70.8 and 89.3%, and a digital DNA-DNA hybridisation identity of between 17.9-28.2% with closely related type strains within the genus Echinicola. The sole menaquinone was MK-7, and the major fatty acids were iso-C_15:0, summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), summed feature 4 (anteiso-C_17:1 B and/or iso-C_17:1 I), and summed feature 9 (iso-C_17:1ω9c and/or 10-methyl C_16:0). The polar lipids included one phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, three unidentified aminolipids, and one unknown lipid. The phenotypic, chemotaxonomic, and phylogenetic analyses suggest that strain P51^T is a novel species of the genus Echinicola, for which the name Echinicola salinicaeni sp. nov. is proposed. The type strain was P51^T (KCTC 82513^T = MCCC 1K04413^T).

Structural and biochemical characterization of the environmental MBLs MYO-1, ECV-1 and SHD-1

BACKGROUND

MBLs form a large and heterogeneous group of bacterial enzymes conferring resistance to β-lactam antibiotics, including carbapenems. A large environmental reservoir of MBLs has been identified, which can act as a source for transfer into human pathogens. Therefore, structural investigation of environmental and clinically rare MBLs can give new insights into structure-activity relationships to explore the role of catalytic and second shell residues, which are under selective pressure.

OBJECTIVES

To investigate the structure and activity of the environmental subclass B1 MBLs MYO-1, SHD-1 and ECV-1.

METHODS

The respective genes of these MBLs were cloned into vectors and expressed in Escherichia coli. Purified enzymes were characterized with respect to their catalytic efficiency (kcat/Km). The enzymatic activities and MICs were determined for a panel of different β-lactams, including penicillins, cephalosporins and carbapenems. Thermostability was measured and structures were solved using X-ray crystallography (MYO-1 and ECV-1) or generated by homology modelling (SHD-1).

RESULTS

Expression of the environmental MBLs in E. coli resulted in the characteristic MBL profile, not affecting aztreonam susceptibility and decreasing susceptibility to carbapenems, cephalosporins and penicillins. The purified enzymes showed variable catalytic activity in the order of <5% to ∼70% compared with the clinically widespread NDM-1. The thermostability of ECV-1 and SHD-1 was up to 8°C higher than that of MYO-1 and NDM-1. Using solved structures and molecular modelling, we identified differences in their second shell composition, possibly responsible for their relatively low hydrolytic activity.

CONCLUSIONS

These results show the importance of environmental species acting as reservoirs for MBL-encoding genes.

Echinicola soli sp. nov., isolated from alkaline saline soil

Strains of Echinicola , thought to play vital roles in the environment for their high enzyme production capacity during decomposition of polysaccharides, are ubiquitous in hypersaline environments. A Gram-negative, non-spore forming, gliding, aerobic bacterial strain, designated LN3S3T, was isolated from alkaline saline soil sampled in Tumd Right Banner, Inner Mongolia, northern PR China. Strain LN3S3T grew at 10–40 °C (optimum, 30 °C), pH 5.0–9.0 (optimum, pH 8.0) and with 0–12.5 % NaCl (optimum, 2.0 %). A phylogenetic tree based on the 16S rRNA gene sequences showed that strain LN3S3T clustered with Echinicola rosea JL3085T and Echinicola strongylocentroti MEBiC08714T, sharing 97.0, 96.7 and <96.50 % of 16S rRNA gene sequence similarities to E. rosea JL3085T, E. strongylocentroti MEBiC08714T and all other type strains. MK-7 was the major respiratory quinone, while phosphatidylethanolamine, two unidentified phospholipids, an unidentified aminophospholipid, an unidentified lipid and two unidentified aminolipids were the major polar lipids. Its major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and summed feature 3 (C16 : 1  ω7c and/or C16 : 1  ω6c). The genome consisted of a circular 5 550 304 bp long chromosome with a DNA G+C content of 44.0 mol%. The average nucleotide identity (ANI), average amino acid identity (AAI) and digital DNA–DNA hybridization (dDDH) values of strain LN3S3T to E. rosea JL3085T and E. strongylocentroti MEBiC08714T were 82.5 and 81.5 %, 87.5 and 86.0 %, and 39.1 and 35.1 %, respectively. Based on physiological, genotypic and phylogenetic analyses, strain LN3S3T could be discriminated from its phylogenetic relatives. Echinicola soli sp. nov. is therefore proposed with strain LN3S3T (=CGMCC 1.17081T=KCTC 72458T) as the type strain.

Complete genome sequence of Echinicola rosea JL3085, a xylan and pectin decomposer

Marine Bacteroidetes are well known for their functional specialization on the decomposition of polysaccharides which results from a great number of carbohydrate-active enzymes. Here we represent the complete genome of a Bacteroitedes member Echinicola rosea JL3085^T that was isolated from surface seawater of the South China Sea. The genome is 6.06 Mbp in size with a GC content of 44.1% and comprises 4613 protein coding genes. A remarkable genomic feature is that the number of glycoside hydrolase genes in the genome of E. rosea JL3085^T is high in comparison with most of the sequenced members of marine Bacteroitedes. E. rosea JL3085^T genome harbored multi-gene polysaccharide utilization loci (PUL) systems involved in the degradation of pectin, xylan and arabinogalactan. The large diversity of hydrolytic enzymes supports the use of E. rosea JL3085^T as a candidate for biotechnological applications in enzymatic conversion of plant polysaccharides.

Magic Pools: Parallel Assessment of Transposon Delivery Vectors in Bacteria

Molecular genetics is indispensable for interrogating the physiology of bacteria. However, the development of a functional genetic system for any given bacterium can be time-consuming. Here, we present a streamlined approach for identifying an effective transposon mutagenesis system for a new bacterium. Our strategy first involves the construction of hundreds of different transposon vector variants, which we term a “magic pool.” The efficacy of each vector in a magic pool is monitored in parallel using a unique DNA barcode that is introduced into each vector design. Using archived DNA “parts,” we next reassemble an effective vector for making a whole-genome transposon mutant library that is suitable for large-scale interrogation of gene function using competitive growth assays. Here, we demonstrate the utility of the magic pool system to make mutant libraries in five genera of bacteria.

Transposon mutagenesis coupled to next-generation sequencing (TnSeq) is a powerful approach for discovering the functions of bacterial genes. However, the development of a suitable TnSeq strategy for a given bacterium can be costly and time-consuming. To meet this challenge, we describe a part-based strategy for constructing libraries of hundreds of transposon delivery vectors, which we term “magic pools.” Within a magic pool, each transposon vector has a different combination of upstream sequences (promoters and ribosome binding sites) and antibiotic resistance markers as well as a random DNA barcode sequence, which allows the tracking of each vector during mutagenesis experiments. To identify an efficient vector for a given bacterium, we mutagenize it with a magic pool and sequence the resulting insertions; we then use this efficient vector to generate a large mutant library. We used the magic pool strategy to construct transposon mutant libraries in five genera of bacteria, including three genera of the phylum Bacteroidetes.

IMPORTANCE Molecular genetics is indispensable for interrogating the physiology of bacteria. However, the development of a functional genetic system for any given bacterium can be time-consuming. Here, we present a streamlined approach for identifying an effective transposon mutagenesis system for a new bacterium. Our strategy first involves the construction of hundreds of different transposon vector variants, which we term a “magic pool.” The efficacy of each vector in a magic pool is monitored in parallel using a unique DNA barcode that is introduced into each vector design. Using archived DNA “parts,” we next reassemble an effective vector for making a whole-genome transposon mutant library that is suitable for large-scale interrogation of gene function using competitive growth assays. Here, we demonstrate the utility of the magic pool system to make mutant libraries in five genera of bacteria.

Importance of inoculum source and initial community structure for biogas production from agricultural substrates

This study evaluated the importance of inoculum source for start-up and operation of biogas processes. Three different inocula with different community structure were used to initiate six laboratory continuous stirred tank reactor (CSTR) processes operated with a grass manure mixture as substrate. The processes were evaluated by chemical and microbiological analysis, by targeting the overall bacterial community and potential cellulose-degrading bacteria. As expected, the results showed a large difference in community structure in the inocula and in process performance during the first hydraulic retention time (HRT). However, the performance and overall microbial community structure became similar in the reactors over time. An inoculum from a high-ammonia process, characterized by low diversity and low degradation efficiency, took the longest time to reach stability and final methane yield. The overall bacterial community was mainly shaped by the operating conditions but, interestingly, potential cellulose-degrading bacteria seemed mainly to originate from the substrate.

Characterization of Potential Polysaccharide Utilization Systems in the Marine Bacteroidetes Gramella Flava JLT2011 Using a Multi-Omics Approach

Members of phylum Bacteroidetes are distributed across diverse marine niches and Flavobacteria is often the predominant bacterial class decomposing algae-derived polysaccharides. Here, we report the complete genome of Gramella flava JLT2011 (Flavobacteria) isolated from surface water of the southeastern Pacific. A remarkable genomic feature is that the number of glycoside hydrolase (GH) genes in the genome of G. flava JLT2011 is more than 2-fold higher than that of other Gramella species. The functional profiles of the GHs suggest extensive variation in Gramella species. Growth experiments revealed that G. flava JLT2011 has the ability to utilize a wide range of polysaccharides for growth such as xylan and homogalacturonan in pectin. Nearly half of all GH genes were located on the multi-gene polysaccharide utilization loci (PUL) or PUL-like systems in G. flava JLT2011. This species was also found to harbor the two xylan PULs and a pectin PUL, respectively. Gene expression data indicated that more GHs and sugar-specific outer-membrane susC-susD systems were found in the presence of xylan than in the presence of pectin, suggesting a different strategy for heteropolymeric xylan and homoglacturonan utilization. Multi-omics data (transcriptomics, proteomics, and metabolomics) indicated that xylan PULs and pectin PUL are respectively involved in the catabolism of their corresponding polysaccharides. This work presents a comparison of polysaccharide decomposition within a genus and expands current knowledge on the diversity and function of PULs in marine Bacteroidetes, thereby deepening our understanding of their ecological role in polysaccharide remineralization in the marine system.

Genome-Based Taxonomic Classification of Bacteroidetes

The bacterial phylum Bacteroidetes, characterized by a distinct gliding motility, occurs in a broad variety of ecosystems, habitats, life styles, and physiologies. Accordingly, taxonomic classification of the phylum, based on a limited number of features, proved difficult and controversial in the past, for example, when decisions were based on unresolved phylogenetic trees of the 16S rRNA gene sequence. Here we use a large collection of type-strain genomes from Bacteroidetes and closely related phyla for assessing their taxonomy based on the principles of phylogenetic classification and trees inferred from genome-scale data. No significant conflict between 16S rRNA gene and whole-genome phylogenetic analysis is found, whereas many but not all of the involved taxa are supported as monophyletic groups, particularly in the genome-scale trees. Phenotypic and phylogenomic features support the separation of Balneolaceae as new phylum Balneolaeota from Rhodothermaeota and of Saprospiraceae as new class Saprospiria from Chitinophagia. Epilithonimonas is nested within the older genus Chryseobacterium and without significant phenotypic differences; thus merging the two genera is proposed. Similarly, Vitellibacter is proposed to be included in Aequorivita. Flexibacter is confirmed as being heterogeneous and dissected, yielding six distinct genera. Hallella seregens is a later heterotypic synonym of Prevotella dentalis. Compared to values directly calculated from genome sequences, the G+C content mentioned in many species descriptions is too imprecise; moreover, corrected G+C content values have a significantly better fit to the phylogeny. Corresponding emendations of species descriptions are provided where necessary. Whereas most observed conflict with the current classification of Bacteroidetes is already visible in 16S rRNA gene trees, as expected whole-genome phylogenies are much better resolved.

The microbial community structure in industrial biogas plants influences the degradation rate of straw and cellulose in batch tests

BACKGROUND

Materials rich in lignocellulose, such as straw, are abundant, cheap and highly interesting for biogas production. However, the complex structure of lignocellulose is difficult for microbial cellulolytic enzymes to access, limiting degradation. The rate of degradation depends on the activity of members of the microbial community, but the knowledge of this community in the biogas process is rather limited. This study, therefore, investigated the degradation rate of cellulose and straw in batch cultivation test initiated with inoculums from four co-digestion biogas plants (CD) and six wastewater treatment plants (WWTP). The results were correlated to the bacterial community by 454-pyrosequencing targeting 16S rRNA gene and by T-RFLP analysis targeting genes of glycoside hydrolase families 5 (cel5) and 48 (cel48), combined with construction of clone libraries.

RESULTS

UniFrac principal coordinate analysis of 16S rRNA gene amplicons revealed a clustering of WWTPs, while the CDs were more separated from each other. Bacteroidetes and Firmicutes dominated the community with a comparably higher abundance of the latter in the processes operating at high ammonia levels. Sequences obtained from the cel5 and cel 48 clone libraries were also mainly related to the phyla Firmicutes and Bacteroidetes and here ammonia was a parameter with a strong impact on the cel5 community. The results from the batch cultivation showed similar degradation pattern for eight of the biogas plants, while two characterised by high ammonia level and low bacterial diversity, showed a clear lower degradation rate. Interestingly, two T-RFs from the cel5 community were positively correlated to high degradation rates of both straw and cellulose. One of the respective partial cel5 sequences shared 100 % identity to Clostridium cellulolyticum.

CONCLUSION

The degradation rate of cellulose and straw varied in the batch tests dependent on the origin of the inoculum and was negatively correlated with the ammonia level. The cellulose-degrading community, targeted by analysis of the glycoside hydrolase families 5 (cel5) and 48 (cel48), showed a dominance of bacteria belonging the Firmicutes and Bacteriodetes, and a positive correlation was found between the cellulose degradation rate of wheat straw with the level of C. cellulolyticum.

Negadavirga shengliensis gen. nov., sp. nov., a novel member of the family Cyclobacteriaceae isolated from oil-contaminated saline soil

Four novel Gram-stain-negative, rod-shaped, and non-motile bacterial strains, SLG210-21(T), SLG210-4, SLG210-5 and SLG210-14, were isolated from oil-contaminated saline soil in Shengli Oilfield, China. Growth were observed at 25-42 °C (optimum 37 °C), in the presence of 0-10 % (w/v) NaCl (optimum 0-1 %) and at pH 4.0-10.0 (optimum pH 7.6-8.6). All the strains were positive for catalase and α, β-galactosidase activities and nitrogen reduction, and negative for oxidase activity, glucose fermentation and hydrolysis of agar, starch, gelatin, Tween 40, 60 and 80. The DNA G+C contents of the four strains were 41.3-43.0 mol% and the predominant respiratory quinones were all menaquinone-7. The major fatty acids were iso-C15:0, anteiso-C15:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:1 ω5c and summed feature 9 (iso-C17:1 ω9c and/or 10-methyl C16:0), while the polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, glycolipid, two unidentified phospholipids and two unidentified amino lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the four strains clustered together to form a stable branch in the family Cyclobacteriaceae, and were most closely related to the genera Cyclobacterium and Echinicola with the 16S rRNA gene sequence similarities being 88.6-90.3 and 89.6-91.4 %, respectively. DNA-DNA hybridization between SLG210-21(T) and the other three strains showed the relatedness of 93.8 ± 4.5, 96.2 ± 4.2 and 82.3 ± 4.8 %, respectively. Based on the polyphasic analysis, a novel species in a new genus, Negadavirga Shengliensis gen. nov., sp. nov., is proposed with SLG210-21(T) (=LMG 27737(T) = CGMCC1.12768(T)) [corrected] as the type strain.

Structure of the O-specific polysaccharide from a marine bacterium Echinicola vietnamensis KММ 6221Т

The O-specific polysaccharide was isolated from the lipopolysaccharide of Echinicola vietnamensis and studied by chemical methods along with 1H and 13C NMR spectroscopy, including 2D 1H, 1H COSY, TOCSY, ROESY, 1H, 13C HSQC, HMBC, and H2BC experiments. It was found that the polysaccharide is built up of branched tetrasaccharide repeating units, containing 2-acetamido-2-deoxy-D-glucuronic acid (GlcNAcA), 2-acetamido-2-deoxy-D-galactose (GalNAc), and D-glucuronic acid (GlcA) with a terminal residue of 3,6-dideoxy-L-xylo-hexose (colitose, Col) and has the following structure. α-Colp1-->2-->4)-β-D-GlcpNAcA-(1-->4)-β-D-GlcpA-(1-->3)-α-D-GalpNAc-(1-->

Comparative analysis of glycoside hydrolases activities from phylogenetically diverse marine bacteria of the genus Arenibacter

A total of 16 marine strains belonging to the genus Arenibacter, recovered from diverse microbial communities associated with various marine habitats and collected from different locations, were evaluated in degradation of natural polysaccharides and chromogenic glycosides. Most strains were affiliated with five recognized species, and some presented three new species within the genus Arenibacter. No strains contained enzymes depolymerizing polysaccharides, but synthesized a wide spectrum of glycosidases. Highly active β-N-acetylglucosaminidases and α-N-acetylgalactosaminidases were the main glycosidases for all Arenibacter. The genes, encoding two new members of glycoside hydrolyses (GH) families, 20 and 109, were isolated and characterized from the genomes of Arenibacter latericius. Molecular genetic analysis using glycosidase-specific primers shows the absence of GH27 and GH36 genes. A sequence comparison with functionally-characterized GH20 and GH109 enzymes shows that both sequences are closest to the enzymes of chitinolytic bacteria Vibrio furnissii and Cellulomonas fimi of marine and terrestrial origin, as well as human pathogen Elisabethkingia meningoseptica and simbionts Akkermansia muciniphila, gut and non-gut Bacteroides, respectively. These results revealed that the genus Arenibacter is a highly taxonomic diverse group of microorganisms, which can participate in degradation of natural polymers in marine environments depending on their niche and habitat adaptations. They are new prospective candidates for biotechnological applications due to their production of unique glycosidases.

Mongoliicoccus roseus gen. nov., sp. nov., an alkaliphilic bacterium isolated from a haloalkaline lake

Two pink, non-motile, aerobic, alkaliphilic, halotolerant, Gram-negative cocci, designated MIM28T and MIM29, were isolated from the surface water of a haloalkaline lake on the Mongolia Plateau. The isolates grew optimally at 30–33 °C, at pH 8–9 and with 3–4 % (w/v) NaCl. The isolates were chemoheterotrophic and could assimilate carbohydrates, organic acids and amino acids. The major respiratory quinone was menaquinone MK-7. The major polar lipids were phosphatidylcholine and phosphatidylethanolamine. The predominant cellular fatty acids were iso-C15 : 0 (13.8–17.5 %), anteiso-C15 : 0 (10.5–11.2 %), iso-C16 : 0 (9.9–13.0 %), C16 : 0 (4.3–4.6 %), iso-C17 : 0 (3.8–5.3 %), anteiso-C17 : 0 (3.7–7.1 %), C17 : 1ω6c (4.6–6.4 %), iso-C17 : 0 3-OH (4.6–5.8 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 4.0–6.4 %) and summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl; 10.4–12.5 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that the isolates were most closely related to Litoribacter ruber YIM CH208T (93.6 % 16S rRNA gene sequence similarity), the genus Echinicola (90.4–92 %) and other members of the family Cyclobacteriaceae (87.8–90 %). The DNA G+C contents of strains MIM28T and MIM29 were 62.8 and 62.2 mol%. On the basis of morphology, physiology, fatty acid composition, phylogeny and 16S rRNA gene sequence analysis, the isolates are assigned to a novel species of a new genus, for which we propose the name Mongoliicoccus roseus gen. nov., sp. nov.; the type strain of the type species is MIM28T ( = ACCC 05511T  = KCTC 19808T).

Mongoliitalea lutea gen. nov., sp. nov., an alkaliphilic, halotolerant bacterium isolated from a haloalkaline lake

Two bacterial isolates from the surface water of a haloalkaline lake on the Mongolia Plateau, strains MIM18T and MIM19, were characterized; their morphological, physiological and chemotaxonomic characters, and phylogenetic position based on 16S rRNA gene sequences, were determined. The two strains were alkaliphilic, halotolerant, non-motile, aerobic, Gram-negative, orange-red, rod-shaped and oxidase-positive. Growth was observed in 0–5.5 % (w/v) NaCl, with optimum growth at 1 %. The temperature range for growth was 0–41 °C, with good growth at 28–37 °C and optimum growth at 30–33 °C. The DNA G+C content was 39.8–41.2 mol%. The strains contained menaquinone MK-7 as the major respiratory quinone and phosphatidylcholine, phosphatidylglycerol and phosphatidylethanolamine as the major polar lipids. Predominant cellular fatty acids were iso-C15 : 0 (28.1–29.3 %), iso-C17 : 0 3-OH (14.6–18.8 %), C15 : 1ω6c (5.3–8.6 %), C14 : 0 2-OH and/or iso-C15 : 0 2-OH (5.4–6.1 %), and iso-C17 : 1ω9c and/or C16 : 0 10-methyl (5.0–6.8 %). 16S rRNA gene sequence analysis showed that Belliella and Nitritalea of the family Cyclobacteriaceae were the closest related species with sequence similarities of 91.7–92.3 % and 88.2 %, respectively, with strains of these genera; other members of the Cyclobacteriaceae had sequence similarities lower than 88 %. Phylogenetic analysis indicated that the strains formed a deep-rooted lineage distinct from the clades represented by the genera Belliella, Nitritalea, Indibacter, Aquiflexum, Echinicola, Litoribacter, Cyclobacterium and Algoriphagus. Based on the phenotypic and phylogenetic characteristics mentioned above, the two strains are representatives of a single novel species in a new genus; the name Mongoliitalea lutea gen. nov., sp. nov. is proposed, with MIM18T ( = ACCC 05421T = KCTC 23224T) as the type strain.

Echinicola jeungdonensis sp. nov., isolated from a solar saltern

A non-motile and yellow-pigmented bacterium, designated strain HMD3054T, was isolated from a solar saltern in Jeungdo, Republic of Korea. The major fatty acids of strain HMD3054T were iso-C15 : 0 (31.4 %), anteiso-C15 : 0 (23.5 %), iso-C17 : 0 3-OH (14.2 %), summed feature 3 (comprising C16 : 1ω6c and/or C16 : 1ω7c; 6.9 %) and summed feature 9 (comprising iso-C17 : 1ω9c and/or 10-methyl C16 : 0; 6.0 %). The major respiratory quinones were MK-6 and MK-7. The DNA G+C content of strain HMD3054T was 46.9 mol%. A phylogenetic tree based on 16S rRNA gene sequences showed that strain HMD3054T formed a lineage within the genus Echinicola. Strain HMD3054T was closely related to Echinicola vietnamensis KMM 6221T (94.3 % 16S rRNA gene sequence similarity) and Echinicola pacifica KMM 6172T (94.0 %). On the basis of the evidence presented in this study, strain HMD3054T represents a novel species of the genus Echinicola, for which the name Echinicola jeungdonensis sp. nov. is proposed. The type strain is HMD3054T ( = KCTC 23122T  = CECT 7682T).

Tunicatimonas pelagia gen. nov., sp. nov., a novel representative of the family Flammeovirgaceae isolated from a sea anemone by the differential growth screening method

A Gram-negative, strictly aerobic, reddish-pink pigmented, non-motile, rod-shaped strain designated N5DB8-4(T), was isolated from an orange-striped sea anemone Diadumene lineata by a differential growth screening method. Phylogenetic analyses based on the 16S rRNA gene sequence revealed that the novel isolate was affiliated with the family Flammeovirgaceae of the phylum Bacteroidetes and that it showed highest sequence similarity (89.1%) to Porifericola rhodea N5EA6-3A2B(T). The strain could be differentiated phenotypically from recognized members of the family Flammeovirgaceae. The G+C content of the DNA is 52.6 mol%, the major respiratory quinone is menaquinone 7 (MK-7) and iso-C15:0, C16:1ω5c and iso-C15:1 G (the double-bond position indicated by capital letter is unknown) were the major fatty acids. From the distinct phylogenetic position and combination of genotypic and phenotypic characteristics, the strain represents a novel taxon for which the name Tunicatimonas pelagia gen. nov., sp. nov. is proposed. The type strain of Tunicatimonas pelagia is N5DB8-4(T) (=KCTC 23473(T )= NBRC 107804(T)).

Litoribacter ruber gen. nov., sp. nov., an alkaliphilic, halotolerant bacterium isolated from a soda lake sediment

A novel alkaliphilic, halotolerant, rod-shaped bacterium, designated strain YIM CH208T, was isolated from a soda lake in Yunnan, south-west China. The taxonomy of strain YIM CH208T was investigated by a polyphasic approach. Strain YIM CH208T was Gram-negative, strictly aerobic and non-motile and formed red colonies. Optimal growth conditions were 28 °C, pH 8.5 and 0.5–2.5 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequence comparisons showed that the isolate formed a distinct line within a clade containing the genus Echinicola in the phylum Bacteroidetes and was related to the species Echinicola pacifica and Rhodonellum psychrophilum, with sequence similarity of 91.7 and 91.6 % to the respective type strains. The DNA G+C content was 45.1 mol%. The major respiratory quinone was menaquinone-7 (MK-7). The predominant cellular fatty acids were iso-C17 : 1 ω9c (19.9 %), C15 : 0 3-OH (12.1 %), iso-C17 : 0 3-OH (11.3 %), summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c; 10.7 %) and C17 : 1 ω6c (8.7 %). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, strain YIM CH208T represents a novel species of a new genus, for which the name Litoribacter ruber gen. nov., sp. nov. is proposed. The type strain of Litoribacter ruber is YIM CH208T (=ACCC 05414T =KCTC 22899T).

Indibacter alkaliphilus gen. nov., sp. nov., an alkaliphilic bacterium isolated from a haloalkaline lake

A novel Gram-stain-negative, rod-shaped, non-motile bacterium, strain LW1T, was isolated from a water sample collected at a depth of 3.5 m from Lonar Lake, Buldhana district, Maharashtra, India. The cell suspension was reddish-orange due to the presence of carotenoids. Strain LW1T was positive for catalase, oxidase, ornithine decarboxylase and lysine decarboxylase and negative for gelatinase, urease and lipase. Fatty acids were dominated by branched-chain fatty acids (>76 %), with a high abundance of iso-C15 : 0 (48 %), anteiso-C15 : 0 (7 %) and iso-C17 : 0 3-OH (11 %). Strain LW1T contained MK-4 and MK-7 as the major respiratory quinones and phosphatidylglycerol, phosphatidylcholine and phosphatidylethanolamine as the major phospholipids. A blast sequence similarity search based on 16S rRNA gene sequences indicated that members of the genera Belliella and Aquiflexum were the nearest phylogenetic neighbours with similarities of 91.8–92.3 %. Phylogenetic analyses indicated that strain LW1T formed a deep-rooted lineage distinct from the clades represented by the genera Belliella, Aquiflexum, Cyclobacterium, Echinicola and Algoriphagus. Based on the above-mentioned phenotypic and phylogenetic characteristics, it is proposed that strain LW1T represents a novel species in a new genus, Indibacter alkaliphilus gen. nov., sp. nov. (type strain LW1T=KCTC 22604T=CCUG 57479T). The genomic DNA G+C content of strain LW1T is 42.7±1 mol%.

Molecular characterization and therapeutic potential of a marine bacterium Pseudoalteromonas sp. KMM 701 alpha-galactosidase

An alpha-galactosidase capable of converting B red blood cells into the universal blood type cells at the neutral pH was produced by a novel obligate marine bacterium strain KMM 701 (VKM B-2135 D). The organism is heterotrophic, aerobic, and halophilic and requires Na+ ions and temperature up to 34 degrees C for its growth. The strain has a unique combination of polysaccharide-degrading enzymes. Its single intracellular alpha-galactosidase exceeded other glycoside hydrolases in the level of expression up to 20-fold. The alpha-galactosidase was purified to determine the N-terminal amino acid sequences and new activities. It was found to inhibit Corynebacterium diphtheria adhesion to host buccal epithelium cell surfaces with high effectiveness. The nucleotide sequence of the homodimeric alpha-galactosidase indicates that its subunit is composed of 710 amino acid residues with a calculated Mr of 80,055. This alpha-galactosidase shares structural property with 36 family glycoside hydrolases. The properties of the enzyme are likely to be highly beneficial for medicinal purposes.