Tahibacter soli sp. nov., isolated from soil and Tahibacter amnicola sp. nov., isolated from freshwater.

Two Gram-stain-negative, facultative aerobic, catalase- and oxidase-positive, and non-motile rod bacteria, strains BLT and W38T, that were isolated from soil and freshwater, respectively, were taxonomically characterized. Both strains optimally grew at 30 °C and pH 7.0 in Reasoner's 2A medium and contained ubiquinone-8 as the sole respiratory quinone. As major fatty acids (>10 %), strain BLT contained iso-C15 : 0 and summed features 3 and 9 (comprising iso-C15 : 0 2-OH and/or C16 : 1 ω7c/ω6c and iso-C17 : 1 ω9c and/or C16 : 0 10-methyl, respectively), whereas strain W38T contained iso-C15 : 0, iso-C16 : 0 and summed feature 9. Diphosphatidylglycerol and phosphatidylmonomethylethanolamine as major polar lipids and phosphatidylethanolamine and phosphatidylglycerol as minor polar lipids were detected in both strains. The DNA G+C contents of strains BLT and W38T were 68.3 and 65.3 %, respectively. Phylogenetic analyses based on 16S rRNA gene and genome sequences revealed that strains BLT and W38T formed a tight phylogenetic lineage with Tahibacter species, and they shared 98.8 % 16S rRNA gene sequence similarity and 75.5 % average nucleotide identity (ANI) and 16.6 % digital DNA-DNA hybridization (dDDH) values, indicating that they are different species. Strains BLT and W38T were most closely related to Tahibacter caeni BUT-6T and Tahibacter aquaticus PYM5-11T with 97.7 and 98.0 % 16S rRNA gene sequence similarities, respectively. ANI and dDDH values between strain BLT and T. caeni BUT-6T and between strain W38T and T. aquaticus DSM 21667T were 78.5 and 21.6% and 75.3 and 21.0 %, respectively. Based on their phenotypic, chemotaxonomic and genomic properties, strains BLT and W38T represent two different novel species of the genus Tahibacter, for which the names Tahibacter soli sp. nov. and Tahibacter amnicola sp. nov. are proposed. The type strains of T. soli and T. amnicola are BLT (=KACC 22831T=JCM 35402T) and W38T (=KACC 22832T=JCM 35749T), respectively.

Humic acids alleviate aflatoxin B1-induced hepatic injury by reprogramming gut microbiota and absorbing toxin.

Aflatoxin B1 (AFB1) is a hepatotoxic fungal metabolite that is widely present in food and can cause liver cancer. As a potential detoxifier, naturally occurring humic acids (HAs) may be able to reduce inflammation and restructure the gut microbiota composition; however, little is known about the mechanism of HAs detoxification as applied to liver cells. In this study, HAs treatment alleviated AFB1-induced liver cell swelling and the infiltration of inflammatory cells. HAs treatment also reinstated various enzyme levels in the liver disturbed by AFB1 and substantially alleviated AFB1-caused oxidative stress and inflammatory responses by enhancing immune functions in mice. Moreover, HAs increased the length of the small intestinal and villus height to restore intestinal permeability, which is impaired by AFB1. In addition, HAs reconstructed the gut microbiota, increasing the relative abundance of Desulfovibrio, Odoribacter, and Alistipes. In vitro and in vivo assays demonstrated that HAs could efficiently remove AFB1 by absorbing the toxin. Therefore, HAs treatment can ameliorate AFB1-induced hepatic injury by enhancing gut barrier function, regulating gut microbiota, and adsorbing toxin.

Ammonium transporter 1 increases rice resistance to sheath blight by promoting nitrogen assimilation and ethylene signalling.

Sheath blight (ShB) significantly threatens rice yield production. However, the underlying mechanism of ShB defence in rice remains largely unknown. Here, we identified a highly ShB-susceptible mutant Ds-m which contained a mutation at the ammonium transporter 1;1 (AMT1;1) D358 N. AMT1;1 D358 N interacts with AMT1;1, AMT1;2 and AMT1;3 to inhibit the ammonium transport activity. The AMT1 RNAi was more susceptible and similar to the AMT1;1 D358 N mutant; however, plants with higher NH4+ uptake activity were less susceptible to ShB. Glutamine synthetase 1;1 (GS1;1) mutant gs1;1 and overexpressors (GS1;1 OXs) were more and less susceptible to ShB respectively. Furthermore, AMT1;1 overexpressor (AMT1;1 OX)/gs1;1 and gs1;1 exhibited a similar response to ShB, suggesting that ammonium assimilation rather than accumulation controls the ShB defence. Genetic and physiological assays further demonstrated that plants with higher amino acid or chlorophyll content promoted rice resistance to ShB. Interestingly, the expression of ethylene-related genes was higher in AMT1;1 OX and lower in RNAi mutants than in wild-type. Also, ethylene signalling positively regulated rice resistance to ShB and NH4+ uptake, suggesting that ethylene signalling acts downstream of AMT and also NH4+ uptake is under feedback control. Taken together, our data demonstrated that the AMT1 promotes rice resistance to ShB via the regulation of diverse metabolic and signalling pathways.

Diet-Related Alterations of Gut Bile Salt Hydrolases Determined Using a Metagenomic Analysis of the Human Microbiome.

The metabolism of bile acid by the gut microbiota is associated with host health. Bile salt hydrolases (BSHs) play a crucial role in controlling microbial bile acid metabolism. Herein, we conducted a comparative study to investigate the alterations in the abundance of BSHs using data from three human studies involving dietary interventions, which included a ketogenetic diet (KD) versus baseline diet (BD), overfeeding diet (OFD) versus underfeeding diet, and low-carbohydrate diet (LCD) versus BD. The KD increased BSH abundance compared to the BD, while the OFD and LCD did not change the total abundance of BSHs in the human gut. BSHs can be classified into seven clusters; Clusters 1 to 4 are relatively abundant in the gut. In the KD cohort, the levels of BSHs from Clusters 1, 3, and 4 increased significantly, whereas there was no notable change in the levels of BSHs from the clusters in the OFD and LCD cohorts. Taxonomic studies showed that members of the phyla Bacteroidetes, Firmicutes, and Actinobacteria predominantly produced BSHs. The KD altered the community structure of BSH-active bacteria, causing an increase in the abundance of Bacteroidetes and decrease in Actinobacteria. In contrast, the abundance of BSH-active Bacteroidetes decreased in the OFD cohort, and no significant change was observed in the LCD cohort. These results highlight that dietary patterns are associated with the abundance of BSHs and community structure of BSH-active bacteria and demonstrate the possibility of manipulating the composition of BSHs in the gut through dietary interventions to impact human health.

Performance Evaluation of Enzyme Breaker for Fracturing Applications under Simulated Reservoir Conditions.

Fracturing fluids are being increasingly used for viscosity development and proppant transport during hydraulic fracturing operations. Furthermore, the breaker is an important additive in fracturing fluid to extensively degrade the polymer mass after fracturing operations, thereby maximizing fracture conductivity and minimizing residual damaging materials. In this study, the efficacy of different enzyme breakers was examined in alkaline and medium-temperature reservoirs. The parameters considered were the effect of the breaker on shear resistance performance and sand-suspending performance of the fracturing fluid, its damage to the reservoir after gel breaking, and its gel-breaking efficiency. The experimental results verified that mannanase II is an enzyme breaker with excellent gel-breaking performance at medium temperatures and alkaline conditions. In addition, mannanase II did not adversely affect the shear resistance performance and sand-suspending performance of the fracturing fluid during hydraulic fracturing. For the same gel-breaking result, the concentration of mannanase II used was only one fifth of other enzyme breakers (e.g., mannanase I, galactosidase, and amylase). Moreover, the amount of residue and the particle size of the residues generated were also significantly lower than those of the ammonium persulfate breaker. Finally, we also examined the viscosity-reducing capability of mannanase II under a wide range of temperatures (104-158 °F) and pH values (7-8.5) to recommend its best-use concentrations under different fracturing conditions. The mannanase has potential for applications in low-permeability oilfield development and to maximize long-term productivity from unconventional oilwells.

Prodigiosin of Serratia marcescens ZPG19 Alters the Gut Microbiota Composition of Kunming Mice.

Prodigiosin is a red pigment produced by Serratia marcescens with anticancer, antimalarial, and antibacterial effects. In this study, we extracted and identified a red pigment from a culture of S. marcescens strain ZPG19 and investigated its effect on the growth performance and intestinal microbiota of Kunming mice. High-performance liquid chromatography/mass spectrometry revealed that the pigment had a mass-to-charge ratio (m/z) of 324.2160, and thus it was identified as prodigiosin. To investigate the effect of prodigiosin on the intestinal microbiota, mice (n = 5) were administered 150 µg/kg/d prodigiosin (crude extract, 95% purity) via the drinking water for 18 days. Administration of prodigiosin did not cause toxicity in mice. High-throughput sequencing analysis revealed that prodigiosin altered the cecum microbiota abundance and diversity; the relative abundance of Desulfovibrio significantly decreased, whereas Lactobacillus reuteri significantly increased. This finding indicates that oral administration of prodigiosin has a beneficial effect on the intestinal microbiota of mice. As prodigiosin is non-toxic to mouse internal organs and improves the mouse intestinal microbiota, we suggest that it is a promising candidate drug to treat intestinal inflammation.

New insight into the classification and evolution of glucose transporters in the Metazoa.

Because glucose is an essential energy source for living organisms, glucose transporters (GLUTs) are present in all species worldwide. Encoded by the solute carrier family 2 gene family, the GLUT proteins generally have 12 transmembrane helices (TMHs). In total, 14 GLUT proteins have been identified in humans (hGLUTs), and they are divided into 3 classes on the basis of their transport characteristics and sequence similarities. Herein, we report the use of protein sequence similarity networks (SSNs) to visualize the sequence trends of 4101 GLUT proteins across the Metazoa. The SSNs separated the metazoan proteins into 3 new classes that were different from the traditional classification system. In the new system, 9 of the 14 hGLUTs (hGLUT1-5, 7, 9, 11, and 14) were grouped into class I, 3 (hGLUT10, 12, and 13) were grouped into class II, and 2 (hGLUT6 and 8) were grouped into class III, as also supported by the phylogenetic tree. Multiple sequence alignments further showed that the conserved residues in each class were different. Furthermore, the hGLUTs in each class showed unique evolutionary characteristics, with similar nonsynonymous-to-synonymous divergence ratios and similar regions under conservative selection pressure. Of note, GLUTs with 3, 6, 18, 24, and 36 TMHs were identified among the metazoan genomes, and 1 Chinese hamster protein with 6 TMHs showed GLUT activity. In summary, this large-scale sequence analysis provided new insights into the classification and evolution of GLUTs and further showed that gene duplication and fusion could have been important drivers during the evolution of these transporter molecules.-Jia, B., Yuan, D. P., Lan, W. J., Xuan, Y. H., Jeon, C. O. New insight into the classification and evolution of glucose transporters in the Metazoa.

Large-scale examination of functional and sequence diversity of 2-oxoglutarate/Fe(II)-dependent oxygenases in Metazoa.

BACKGROUND: The 2-oxoglutarate/Fe(II)-dependent oxygenase (2OG oxygenase) superfamily in Metazoa is responsible for protein modification, nucleic acid repair and/or modification, and fatty acid metabolism. METHODS: Phylogenetic analysis, protein sequence similarity network (SSN) and other bioinformatics tools were used to analyze the evolutionary relationship and make functional inferences of Metazoa 2OG oxygenases. RESULTS: Sixty-four 2OG oxygenases have been previously found in Homo sapiens; they catalyze two reactions: hydroxylation and demethylation. Phylogenetic analyses indicated that enzymes with similar domain architecture are always clustered together, and the redox function can be performed by the 2OG oxygenase domain or Jumonji C (JmjC) domain, where the JmjC domain is always fused to other functional domains. We used the SSN to make functional inferences and to conduct distribution analysis of Metazoa 2OG oxygenases. >11,000 putative 2OG oxygenases across Metazoa could be assigned potential functions based on the SSN. The multiple sequence alignments showed that the residues binding iron are most highly conserved in both the 2OG oxygenase domain and JmjC domain. In contrast, the residues binding oxoglutarate are quite different in the two domains: the 2OG oxygenase domain tends to have an Arg/Lys at the C terminus, whereas the JmjC domain, an Asn/Lys residue in the middle region. CONCLUSIONS: The results indicated that gene duplication and vertical gene transfer have played important roles in 2OG oxygenase evolution in Metazoa and clarified the difference between the 2OG oxygenase domain and JmjC domain. GENERAL SIGNIFICANCE: These findings expand the understanding of the diversity, evolution, and functions of 2OG oxygenases.

Integrative view of 2-oxoglutarate/Fe(II)-dependent oxygenase diversity and functions in bacteria.

BACKGROUND: The 2-oxoglutarate/Fe(II)-dependent oxygenase (2OG oxygenase) superfamily is extremely diverse and includes enzymes responsible for protein modification, DNA and mRNA repair, and synthesis of secondary metabolites. METHODS: To investigate the evolutionary relationship and make functional inferences within this remarkably diverse superfamily in bacteria, we used a protein sequence similarity network and other bioinformatics tools to analyze the bacterial proteins in the superfamily. RESULTS: The network based on experimentally characterized 2OG oxygenases reflects functional clustering. Networks based on all of the bacterial 2OG oxygenases from the Interpro database indicate that only few proteins in this superfamily are functionally defined. The uneven distribution of the enzymes supports the hypothesis that horizontal gene transfer plays an important role in 2OG oxygenase evolution. A hydrophobic tyrosine residue binding the primary substrates at the N-termini is conserved. At the C-termini, the iron-binding, oxoglutarate-binding, and hydrophobic motifs are conserved and coevolved. Considering the proteins in the family are largely unexplored, we annotated them by the Pfam database and hundreds of novel and multi-domain proteins are discovered. Among them, a two-domain protein containing an N-terminal peroxiredoxin domain and a C-terminal 2OG oxygenase domain was characterized enzymatically. The results show that the enzyme could catalyze the reduction of peroxide using 2-oxoglutarate as an electron donor. CONCLUSIONS: Our observations suggest relatively low evolutionary pressure on the bacterial 2OG oxygenases and a straightforward electron transfer pathway catalyzed by the two-domain 2OG oxygenase. GENERAL SIGNIFICANCE: This work enables an expanded understanding of the diversity, evolution, and functions of bacterial 2OG oxygenases.

Algoriphagus aestuariicola sp. nov., isolated from estuary sediment.

A Gram-staining-negative and strictly aerobic bacterium, designated strain S2-A1T, was isolated from estuary sediment in South Korea. Cells of strain S2-A1T were oxidase- and catalase-positive rods without a gliding motility. Growth was observed at 15-40 °C (optimum, 37 °C), at pH 6.0-10.0 (optimum, pH 7.0-7.5) and in the presence of 0-4.0 % (w/v) NaCl (optimum, 0.5-1.0 %). The sole respiratory quinone was MK-7. iso-C15 : 0, summed feature 3 (comprising C16 : 1ω7c/C16 : 1ω6c) and summed feature 9 (comprising iso-C17 : 1ω9c/C16 : 0 10-methyl) were found as the major fatty acids (>5 % of the total fatty acids). The polar lipids of strain S2-A1T consisted of phosphatidylethanolamine, an unidentified aminophospholipid, three unidentified aminolipids and five unidentified lipids. The G+C content of the genomic DNA was 45.6 mol%. Strain S2-A1T was most closely related to Algoriphagus taeanensisHMC4223T with a 97.7 % 16S rRNA gene sequence similarity. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain S2-A1T formed a tight phyletic lineage with members of the genus Algoriphagus. On the basis of phenotypic, chemotaxonomic and molecular features, strain S2-A1T clearly represents a novel species of the genus Algoriphagus, for which the name Algoriphagus aestuariicola sp. nov. is proposed. The type strain is S2-A1T (=KACC 18987T=JCM 31546T).

Roseovarius confluentis sp. nov., isolated from estuary sediment.

A Gram-stain-negative and strictly aerobic bacterium, designated strain SAG6T, was isolated from estuary sediment in South Korea. Cells of strain SAG6T were found to be oxidase- and catalase-positive rods with gliding motility. Cell growth was observed at 15-40 °C (optimum 30 °C), at pH 6.5-10.0 (optimum pH 7.0) and in the presence of 0.5-13.0 % (w/v) NaCl (optimum 2.0 %). Ubiquinone-10 was the only detected respiratory quinone and summed feature 8 (comprising C18 : 1ω7c/C18 : 1ω6c), C16 : 0, C18 : 1ω7c 11-methyl and C12 : 0 were the major fatty acids identified (>5 % of the total fatty acids). The polar lipids of strain SAG6T consisted of phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, an unidentified aminolipid and two unidentified lipids. The G+C content of the genomic DNA was 66.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SAG6T formed a tight phyletic lineage within the genus Roseovarius. Strain SAG6T was most closely related to Roseovarius indicus B108T with 97.6 % 16S rRNA gene sequence similarity. Based on phenotypic, chemotaxonomic and molecular features, strain SAG6T clearly represents a novel species of the genus Roseovarius, for which the name Roseovarius confluentis sp. nov. is proposed. The type strain is SAG6T (=KACC 18598T=JCM 31541T).

Pandoraea terrae sp. nov., isolated from forest soil, and emended description of the genus Pandoraea Coenye et al. 2000.

A Gram-staining-negative, facultatively aerobic, white-colony-forming bacterium, designated strain SE-S21T, was isolated from forest soil of Jeju Island in Korea. Cells were motile rods with a single polar flagellum, showing catalase- and oxidase-positive reactions. Growth was observed at 10-40 °C (optimum, 30 °C), pH 4.0-10.0 (optimum, pH 7.0-7.5) and with 0-4.0 % (w/v) NaCl (optimum, 0-2 %). Only ubiquinone-8 was detected as the isoprenoid quinone, and C16 : 0, C17 : 0 cyclo, C19 : 1ω8c cyclo and summed feature 2 (comprising C12 : 0 aldehyde and/or unknown) were found to be the major fatty acids. Phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, an unknown aminophospholipid, an unknown aminolipid and an unknown lipid were detected as the major polar lipids. Putrescine and 2-hydroxyputrescine were the predominant polyamines. The DNA G+C content was 61.0 mol%. Phylogenetic analyses based on 16S rRNA and DNA gyrase B gene sequences revealed that strain SE-S21T formed a phyletic lineage within the genus Pandoraea. Strain SE-S21T was most closely related to Pandoraea faecigallinarum KOxT and Pandoraea pnomenusa CCUG 38742T with 98.8 % and 98.7 % 16S rRNA gene sequence similarities, respectively. However, the DNA-DNA relatedness values between strain SE-S21T and the type strains of P. faecigallinarum and P. pnomenusa were 26.6±5.7 % and 20.5±3.7 %, respectively. On the basis of phenotypic, chemotaxonomic and molecular features, strain SE-S21T clearly represents a novel species of the genus Pandoraea, for which the name Pandoraea terrae sp. nov. is proposed. The type strain is SE-S21T (=KACC 18127T=JCM 30137T). An emended description of the genus Pandoraea is also proposed.

Pseudogracilibacillus marinus sp. nov., isolated from a biofilm formed in coastal seawater.

A Gram-staining-positive, aerobic, motile, rod-shaped (0.4-0.5×2.0-4.0 µm), endospore-forming bacterium, designated strain NIOT.bflm.S4T, was isolated from biofilm formed on high-density polyethylene test coupons in coastal seawater. The strain required seawater for growth. It grew with 1.0-8.0 % (w/v) NaCl, at 4-45 °C and at pH 6.5-9.0, with optimum growth with 4.0-5.0 % (w/v) NaCl, at 30 °C and at pH 7.0-8.0. Phylogenetic analyses based on 16S rRNA and partial dnaK gene sequences showed that strain NIOT.bflm.S4T formed a phylogenetic lineage with Pseudogracilibacillus auburnensis P-207T, the only known species of the genus Pseudogracilibacillusand shared sequence identities of 96.9 and 83 %, respectively, with this strain. The identities of 16S rRNA and partial dnaK gene sequences with members of other related genera such as Gracilibacillus, Paraliobacillus, Ornithinibacillus, Oceanobacillus, Virgibacillus and Lentibacillus were ≤95 and ≤78 %, respectively. The DNA G+C content of strain NIOT.bflm.S4T was 39.1 mol%. MK-7 was found as the sole isoprenoid quinone. The major polar lipids of strain NIOT.bflm.S4T were diphosphatidylglycerol, phosphatidylethanolamine and an unknown lipid. The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. Major cellular fatty acids were anteiso-C15 : 0 (27.9 %), anteiso-C17 : 0 (18.6 %), C12 : 0 (8.7 %) and iso-C15 : 0 (6.6 %). On the basis of phenotypic, phylogenetic and chemotaxonomic results, we propose that the isolate represents a novel species of the genus Pseudogracilibacillus, for which the name Pseudogracilibacillus marinus sp. nov. is proposed. The type strain is NIOT.bflm.S4T (=KACC 18456T=MTCC 12376T=TBRC 5831T).

Recombinant cyclodextrinase from Thermococcus kodakarensis KOD1: expression, purification, and enzymatic characterization.

A gene encoding a cyclodextrinase from Thermococcus kodakarensis KOD1 (CDase-Tk) was identified and characterized. The gene encodes a protein of 656 amino acid residues with a molecular mass of 76.4 kDa harboring four conserved regions found in all members of the α-amylase family. A recombinant form of the enzyme was purified by ion-exchange chromatography, and its catalytic properties were examined. The enzyme was active in a broad range of pH conditions (pHs 4.0-10.0), with an optimal pH of 7.5 and a temperature optimum of 65°C. The purified enzyme preferred to hydrolyze ß-cyclodextrin (CD) but not α- or γ-CD, soluble starch, or pullulan. The final product from ß-CD was glucose. The V max and K m values were 3.13 ± 0.47 U mg(-1) and 2.94 ± 0.16 mg mL(-1) for ß-CD. The unique characteristics of CDase-Tk with a low catalytic temperature and substrate specificity are discussed, and the starch utilization pathway in a broad range of temperatures is also proposed.

Aestuariicella hydrocarbonica gen. nov., sp. nov., an aliphatic hydrocarbon-degrading bacterium isolated from a sea tidal flat.

A Gram-staining-negative, strictly aerobic bacterial strain, designated SM-6T, was isolated from a sea tidal flat of the Dangjin bay, South Korea. Strain SM-6T was able to degrade a broad range of aliphatic hydrocarbons. Cells were catalase- and oxidase-positive and non-motile rods. Growth of strain SM-6T was observed at 10-37 °C (optimum, 20-25 °C), at pH 5.5-9.0 (optimum, pH 6.5-7.5) and in the presence of 0-10 % (w/v) NaCl (optimum, 2-3 %). The only isoprenoid quinone detected was ubiquinone-8 (Q-8). C17:1ω8c, C11:0 3-OH, summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c), C9:0 3-OH and C10:0 3-OH were observed as the major cellular fatty acids and phosphatidylethanolamine, phosphatidylglycerol and four unidentified lipids were detected as polar lipids. The G+C content of the genomic DNA was 47.5 mol%. Strain SM-6T was most closely related to Pseudomaricurvus alkylphenolicus KU41GT (95.5 %), Maricurvus nonylphenolicus KU41ET (94.4 %) and Pseudoteredinibacter isoporae SW-11T (94.3 %), based on 16S rRNA gene sequences, and phylogenetic analyses showed that strain SM-6T formed a phyletic lineage distinct from the closely related genera. On the basis of phenotypic, chemotaxonomic and molecular features, strain SM-6T represents a novel genus and species of the order Alteromonadales in the class Gammaproteobacteria, for which name Aestuariicella hydrocarbonica gen. nov., sp. nov. is proposed. The type strain is SM-6T ( = KACC 18121T = JCM 30134T).

Celeribacter naphthalenivorans sp. nov., a naphthalene-degrading bacterium from tidal flat sediment.

A Gram-stain-negative, aerobic and moderately halophilic bacterium, designated strain EMB201(T), was isolated from tidal flat sediment of the South Sea in Korea. Cells were motile rods with a single polar flagellum and had catalase- and oxidase-positive activities. Growth of strain EMB201(T) was observed at 15-37 °C (optimum, 30 °C), at pH 5.0-9.5 (optimum, pH 7.0-7.5) and in the presence of 1-7% (w/v) NaCl (optimum, 2-3%). Strain EMB201(T) contained ubiquinone-10 as the sole isoprenoid quinone and summed feature 8 (comprising C18 : 1ω7c/ω6c), C18 : 0ω7c 11-methyl and C10 : 0 3-OH as the major fatty acids. Phosphatidylglycerol and an unidentified amino lipid were identified as the major polar lipids and an unidentified phospholipid and three unidentified lipids were detected as minor components. The G+C content of the genomic DNA was approximately 58.4 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain EMB201(T) formed a phylogenetic lineage with members of the genus Celeribacter. Strain EMB201(T) was related most closely to Celeribacter halophilus ZXM137(T) with a 16S rRNA gene sequence similarity of 98.3%, and the level of DNA-DNA relatedness between the two strains was 17.0 ± 2.0%. The combined chemotaxonomic and molecular properties suggest that strain EMB201(T) represents a novel species of the genus Celeribacter, for which the name Celeribacter naphthalenivorans sp. nov. is proposed. The type strain is EMB201(T) ( = KACC 18393(T) = JCM 30679(T)).

Abiotic stress resistance, a novel moonlighting function of ribosomal protein RPL44 in the halophilic fungus Aspergillus glaucus.

Ribosomal proteins are highly conserved components of basal cellular organelles, primarily involved in the translation of mRNA leading to protein synthesis. However, certain ribosomal proteins moonlight in the development and differentiation of organisms. In this study, the ribosomal protein L44 (RPL44), associated with salt resistance, was screened from the halophilic fungus Aspergillus glaucus (AgRPL44), and its activity was investigated in Saccharomyces cerevisiae and Nicotiana tabacum. Sequence alignment revealed that AgRPL44 is one of the proteins of the large ribosomal subunit 60S. Expression of AgRPL44 was upregulated via treatment with salt, sorbitol, or heavy metals to demonstrate its response to osmotic stress. A homologous sequence from the model fungus Magnaporthe oryzae, MoRPL44, was cloned and compared with AgRPL44 in a yeast expression system. The results indicated that yeast cells with overexpressed AgRPL44 were more resistant to salt, drought, and heavy metals than were yeast cells expressing MoRPL44 at a similar level of stress. When AgRPL44 was introduced into M. oryzae, the transformants displayed obviously enhanced tolerance to salt and drought, indicating the potential value of AgRPL44 for genetic applications. To verify the value of its application in plants, tobacco was transformed with AgRPL44, and the results were similar. Taken together, we conclude that AgRPL44 supports abiotic stress resistance and may have value for genetic application.

Architecture and characterization of a thermostable MoxR family AAA(+) ATPase from Thermococcus kodakarensis KOD1.

AAA(+) ATPases are ubiquitous enzymes that can function as molecular chaperones, employing the energy obtained from ATP hydrolysis to remodel macromolecules. In this report, the MoxR enzyme from Thermococcus kodakarensis KOD1 (TkMoxR) was shown to have two native forms: a two-stack hexameric ring and a hexameric structure, under physiological conditions and cold stress, respectively. TkMoxR was altered to a microtubule-like form in the presence of ATP and tightly interacted with dsDNA molecules of various lengths. In addition, the two-stack hexameric protein catalyzed dsDNA decomposition to form and then release ssDNA, whereas the hexamer TkMoxR structure interacted with but did not release dsDNA. These results suggest that TkMoxR has DNA helicase activity involved in gene expression control.