Evaluation of probiotic properties of Lysinibacillus macroides under in vitro conditions and culture of Cyprinus carpio on growth parameters.

Cyprinus carpio is an important freshwater fish in aquaculture. It was used for the isolation of potential probiotic strain for aquaculture applications. The most dominant strain was isolated on MRS agar from the gastrointestinal (GI) of C. carpio and identified as Lysinibacillus macroides using molecular marker 16S rRNA gene. Various probiotic properties such as acid and bile tolerance and antibiotic susceptibility were analysed under in vitro conditions. Further, formulate pelletized feed using probiotic (L. macroides) in different concentrations (2, 4, 6 and 8%). Rearing of C. carpio was carried out 45 days and fed with formulated feed. The highest length (5.14 ± 0.07 cm) and weight (3.56 ± 0.07 g) of C. carpio fingerlings was recorded in the 8% LM probiotic pelletized feed, while in fingerlings fed with control showed lower in the length (3.02 ± 0.13 cm) and the weight (0.92 ± 0.04 g) on the 45th day of the experiment. Both percentage of weight gain (PWG) and specific growth rate (SGR) were significantly increased (P < 0.05) of C. carpio fingerlings fed with probiotic feed compared to control feed. Hence, the use of probiotic bacteria could be an encouraging alternative feed for future endeavours in the field of aquaculture. In conclusion, L. macroides can serve as probiotic for sustainable, competitive and promising beneficial bacteria to aquaculture industry.

Characterization of the major antifungal extrolite from rice endophyte Lysinibacillus sphaericus against Rhizoctonia solani.

Sheath blight of rice caused by Rhizoctonia solani is regarded as one of the most widely distributed diseases of rice, and is one of the major production constraints for rice in India and most rice-growing countries of Asia. Biological control of plant diseases using antagonistic bacteria is now considered as a promising alternative to the use of hazardous chemical fungicides or bactericides. Several bacterial endophytes have been reported to support growth and improve the health of the plants and therefore, may be important as biocontrol agents. In the present study, putative antifungal metabolites were extracted from rice foliage endophyte Lysinibacillus sphaericus KJ872548 by solvent extraction methods and purified using HPTLC techniques. Separated bands were subjected to assess the in vitro antagonistic activity toward rice sheath blight pathogen Rhizoctonia solani using a dual culture method. Partially purified active fraction B2 obtained from HPTLC analysis showed the highest percentage of inhibition (76.9%). GC MS and FTIR analyses of B2 revealed the compound as1, 2-Benzenedicarboxylic acid butyl 2-Ethylhexyl ester, a strong antifungal volatile organic compound. Light microscopic analysis of the fungal mycelium from the dual culture plate of both culture filtrate and 1, 2-Benzenedicarboxylic acid butyl 2-Ethylhexyl ester disclosed strong mycolytic activity as evident by mycelial distractions and shrinkage. This is the first report on antifungal production by endophytic Lysinibacillus sphaericus against R. solani, the rice sheath blight pathogen. The findings of this study biologically prospect the endophyte L. sphaericus as an inexpensive broad spectrum bioagent for eco-friendly, economic and sustainable agriculture.

A systematic review of the genera Geobacillus and Parageobacillus: their evolution, current taxonomic status and major applications.

The genus Geobacillus, belonging to the phylum Firmicutes, is one of the most important genera and comprises thermophilic bacteria. The genus Geobacillus was erected with the taxonomic reclassification of various Bacillus species. Taxonomic studies of Geobacillus remain in progress. However, there is no comprehensive review of the characteristic features, taxonomic status and study of various applications of this interesting genus. The main aim of this review is to give a comprehensive account of the genus Geobacillus. At present the genus acomprises 25 taxa, 14 validly published (with correct name), nine validly published (with synonyms) and two not validly published species. We describe only validly published species of the genera Geobacillus and Parageobacillus. Vegetative cells of Geobacillus species are Gram-strain-positive or -variable, rod-shaped, motile, endospore-forming, aerobic or facultatively anaerobic, obligately thermophilic and chemo-organotrophic. Growth occurs in the pH range 6.08.5 and a temperature of 37-75 °C. The major cellular fatty acids are iso-C15:o, iso-C16:0 and iso-C17:o. The main menaquinone type is MK-7. The G-+C content of the DNA ranges between 48.2 and 58 mol%. The genus Geobacillus is widely distributed in nature, being mostly found in many extreme locations such as hot springs, hydrothermal vents, marine trenches, hay composts, etc. Geobacillus species have been widely exploited in various industrial and biotechnological applications, and thus are promising candidates for further studies in the future.

An alkaliphilic bacterium BKH4 of Bakreshwar hot spring pertinent to bioconcrete technology.

AIMS: Hot springs have always drawn attention due to their unique chemical richness and the presence of different microbial communities. The use of hot spring bacteria in concrete technology is our primary focus; isolation of an alkaliphilic bacterium from the Bakreshwar hot springs having longer survival and better efficacy towards cementitious environment was the basis of our study's design. METHODS AND RESULTS: A novel facultative anaerobic and highly alkaliphilic bacterial strain (BKH4; GenBank accession no. KX622782) belonging to the family 'Bacillaceae' and homologous (99%) with Lysinibacillus fusiformis was isolated from Bakreshwar hot springs. The isolated coccoid-type Gram-positive bacterium grows well in a defined semi-synthetic medium (pH 12·0 and 65°C). This bacterium survives for more than a month and shows better efficacy in enhancing compressive strengths (>50%), ultrasonic pulse velocity (>25%) and durability of the cementitious mortar when incorporated at a concentration of 104  cells per ml of water used. CONCLUSION: The novel bacterium BKH4 is more effective for the enhancement of the bioconcrete properties. SIGNIFICANCE AND IMPACT OF THE STUDY: BKH4 bacterium will add a new dimension to future concrete technology for its usefulness in strength enhancement and durability due to its alkaliphilic nature and longer survival within a cementitious environment.

Genomic comparison of facultatively anaerobic and obligatory aerobic Caldibacillus debilis strains GB1 and Tf helps explain physiological differences.

Caldibacillus debilis strains GB1 and Tf display distinct phenotypes. Caldibacillus debilis GB1 is capable of anaerobic growth and can synthesize ethanol while C. debilis Tf cannot. Comparison of the GB1 and Tf genome sequences revealed that the genomes were highly similar in gene content and showed a high level of synteny. At the genome scale, there were several large sections of DNA that appeared to be from lateral gene transfer into the GB1 genome. Tf did have unique genetic content but at a much smaller scale: 300 genes in Tf verses 857 genes in GB1 that matched at ≤90% sequence similarity. Gene complement and copy number of genes for the glycolysis, tricarboxylic acid cycle, and electron transport chain pathways were identical in both strains. While Tf is an obligate aerobe, it possesses the gene complement for an anaerobic lifestyle (ldh, ak, pta, adhE, pfl). As a species, other strains of C. debilis should be expected to have the potential for anaerobic growth. Assaying the whole cell lysate for alcohol dehydrogenase activity revealed an approximately 2-fold increase in the enzymatic activity in GB1 when compared with Tf.

Two selenium tolerant Lysinibacillus sp. strains are capable of reducing selenite to elemental Se efficiently under aerobic conditions.

Microbes play important roles in the transport and transformation of selenium (Se) in the environment, thereby influencing plant resistance to Se and Se accumulation in plant. The objectives are to characterize the bacteria with high Se tolerance and reduction capacity and explore the significance of microbial origins on their Se tolerance, reduction rate and efficiency. Two bacterial strains were isolated from a naturally occurred Se-rich soil at tea orchard in southern Anhui Province, China. The reduction kinetics of selenite was investigated and the reducing product was characterized using scanning electron microscopy and transmission electron microscopy-energy dispersive spectroscopy. The bacteria were identified as Lysinibacillus xylanilyticus and Lysinibacillus macrolides, respectively, using morphological, physiological and molecular methods. The results showed that the minimal inhibitory concentrations (MICs) of selenite for L. xylanilyticus and L. macrolides were 120 and 220 mmol/L, respectively, while MICs of selenate for L. xylanilyticus and L. macrolides were 800 and 700 mmol/L, respectively. Both strains aerobically reduced selenite with an initial concentration of 1.0 mmol/L to elemental Se nanoparticles (SeNPs) completely within 36 hr. Biogenic SeNPs were observed both inside and outside the cells suggesting either an intra- or extracellular reduction process. Our study implied that the microbes from Se-rich environments were more tolerant to Se and generally quicker and more efficient than those from Se-free habitats in the reduction of Se oxyanions. The bacterial strains with high Se reduction capacity and the biological synthesized SeNPs would have potential applications in agriculture, food, environment and medicine.

Effects of plant- and animal-based high-fat diets on lipid storage and distribution in environmental bacteria-colonized gnotobiotic mice.

Different edible oils such as lard and soybean oil have been reported to interact with the gut microbiota, affecting host lipid metabolism. However, whether bacteria derived from the environment influence host lipid metabolism remains unclear. This study aimed to clarify the roles of environmental bacteria in host lipid storage and distribution with various edible oils. Gnotobiotic C57BL/6JNarl mice were inoculated with Lysinibacillus xylanilyticus and Paenibacillus azoreducens and then fed either a normal diet (LabDiet 5010, control group) or a diet containing 60% lard (L-group) or soybean oil (S-group) for 18 months. Interestingly, the S-group accumulated massive amounts of white adipose tissue compared to the L- and control groups, while the L-group displayed more hepatic steatosis and fatty droplets than the other groups. The expression of fatty acid synthase (FAS), hydroxymethylglutaryl-coenzyme A reductase (HMGCR), sterol regulatory element-binding protein 2 (SREBP2), and peroxisome proliferator-activated receptor gamma (PPARγ) in the livers of the L-group were markedly elevated compared to the S-group. FAS and PPARγ protein levels were also markedly elevated. However, there were no differences in the expression of the pro-inflammatory cytokines interleukin-6 and tumor necrosis factor-α between the groups. Our results suggest that environmental bacteria may affect host hepatic inflammation and lipid distribution in the presence of high-fat diets, with different effects depending on the fat type consumed.

Diversity of Bacillus-like bacterial community in the sediments of the Bamenwan mangrove wetland in Hainan, China.

Members of the genus Bacillus and related spore-forming genera are ubiquitous. However, Bacillus-like species isolated from marine sediments have attracted less interest than their terrestrial relatives. Here, we investigated the diversity of Bacillus-like bacterial communities in the sediments of the Bamenwan mangrove wetland in Hainan, China, using culture-dependent and culture-independent methods, and present the first report on this subject. We also discovered some potential novel species from the sediment samples. Four families, Bacillaceae (58%), Paenibacillaceae (22%), Alicyclobacillaceae (15%), and Planococcaceae (5%), and 9 genera, Bacillus (42%), Paenibacillus (16%), Halobacillus (13%), Alicyclobacillus (11%), Rummeliibacillus (5%), Cohnella (5%), Tumebacillus (4%), Pontibacillus (3%), and Aneurinibacillus (2%), were identified by pyrosequencing. In contrast, only 4 genera, Bacillus (57%), Paenibacillus (23%), Halobacillus (14%), and Virgibacillus (6%), were detected by the culture-dependent method. In the 16S rDNA sequencing analysis, the isolates HB12036 and HB12037 were closest to Bacillus okuhidensis Kh10-101T and Paenibacillus xylanilyticus XIL14T with similarities of 94.8% and 95.9%, respectively, indicating that these were novel species. Bacillus sp. HB12035 and HB12040 exhibited antimicrobial activity against Staphylococcus aureus ATCC 25923, and Bacillus sp. HB12033 exhibited antimicrobial activity against Ustilago scitaminea Syd.

Biofilm characteristics and evaluation of the sanitation procedures of thermophilic Aeribacillus pallidus E334 biofilms.

The ability of Aeribacillus pallidus E334 to produce pellicle and form a biofilm was studied. Optimal biofilm formation occurred at 60 °C, pH 7.5 and 1.5% NaCl. Extra polymeric substances (EPS) were composed of proteins and eDNA (21.4 kb). E334 formed biofilm on many surfaces, but mostly preferred polypropylene and glass. Using CLSM analysis, the network-like structure of the EPS was observed. The A. pallidus biofilm had a novel eDNA content. DNaseI susceptibility (86.8% removal) of eDNA revealed its importance in mature biofilms, but the purified eDNA was resistant to DNaseI, probably due to its extended folding outside the matrix. Among 15 cleaning agents, biofilms could be removed with alkaline protease and sodium dodecyl sulphate (SDS). The removal of cells from polypropylene and biomass on glass was achieved with combined SDS/alkaline protease treatment. Strong A. pallidus biofilms could cause risks for industrial processes and abiotic surfaces must be taken into consideration in terms of sanitation procedures.

Microbial fuel cell characterisation and evaluation of Lysinibacillus macroides MFC02 electrigenic capability.

Microbial fuel cell (MFC) is the most prominent research field due to its capability to generate electricity by utilizing the renewable sources. In the present study, Two MFC designs namely, H type-Microbial fuel cell (HT-MFC) and U type-Microbial fuel cell (UT-MFC) were constructed based on standardized H shaped anode and cathode compartment as well as U shaped anode and cathode compartments, respectively. In order to lower the cost for MFC construction, Pencil graphite lead was used as electrode and salt agar as Proton exchange membrane. Results inferred that newly constructed UT-MFC showed high electron production when compared to the HT-MFC. UT-MFC displayed an output of about 377 ± 18.85 mV (millivolts); whereas HT-MFC rendered only 237 ± 11.85 mV (millivolts) of power generation, which might be due to the low internal resistance. By increasing the number of cathode in UT-MFC, power production was increased upto 313 ± 15.65 mV in Open circuit voltage (OCV). Electrogenic bacteria namely, Lysinibacillus macroides (Acc. No. KX011879) rendered enriched power generation. The attachment of bacteria as a biofilm on pencil graphite lead was analyzed using fluorescent microscope and Scanning Electron Microscope (SEM). Based on our findings, it was observed that UT-MFC has a tendency to produce high electron generation using pencil graphite lead as the electrode material.

Determination of the biofilm production capacities and characteristics of members belonging to Bacillaceae family.

The biofilm characteristics of many endospore-forming bacilli, especially the thermophiles are still unclear. In this study, a detailed identification and description of biofilm production characteristics of totally 145 isolates and reference strains belonging to Bacillaceae family, displaying thermophilic (n = 115), facultative thermophilic (n = 24) and mesophilic (n = 6) growth from genera Anoxybacillus, Geobacillus, Thermolongibacillus, Aeribacillus, Brevibacillus, Paenibacillus and Bacillus were presented. The incubation temperatures were adjusted to 37, 45 and 55-65 °C for mesophiles, facultative thermophiles, and thermophiles, respectively. The bacilli were evaluated based on their colony morphotypes on Congo red (CR) agar, their complex exopolysaccharide production on calcofluor supplemented tryptic soy agar, and as well as their pellicle formation at the liquid-air surface in tryptic soy broth cultures. Their biofilm production capabilities were also tested on abiotic surfaces of both polystyrene and stainless steel by crystal violet binding assay and viable biofilm cell enumerations, respectively. As a result, the biofilm production capacities of Bacillaceae members from genera to species level, the effects of osmolarity, temperature, incubation time and abiotic surfaces on biofilm formation as well as the CR morphotypes associated with the biofilm production were able to reveal in a wide group of bacilli. Besides, general enrichment-inoculation approaches and methodologies were also offered, which allow and facilitate the screening and determining the biofilm producing endospore forming bacilli.

Adsorption of Toxic Metals and Control of Mosquitos-borne Disease by Lysinibacillus sphaericus: Dual Benefits for Health and Environment.

OBJECTIVE: Assessment of the bacterium L. sphaericus as a dual-action candidate for biological control of mosquito-borne diseases and bioremediation of toxic metals. METHODS: Larvae of the mosquito, C. quinquefasciatus, were first evaluated for metal tolerance and then exposed to 5 ppm cadmium, chromium, arsenic, and lead in assays together with seven strains of L. sphaericus. A probit regression analysis was used to estimate the LC(50) of Cd, Cr, As, and Pb to C. quinquefasciatus. An analysis of covariance and multifactorial ANOVA examined the metal biosorption and larvicidal properties of the seven strains of L. sphaericus. RESULTS: We found that L. sphaericus adsorbed the toxic metal ions and was toxic against mosquito larvae. The L. sphaericus strain III(3)7 resulted in a larvae mortality of over 80% for all the tested metals. This strain also exhibited the capacity to adsorb 76% of arsenic, 32% of lead, 25% of chromium, and 7% of cadmium. CONCLUSION: This study found combined metal adsorption and larval toxicity associated with three strains of L. sphaericus [III(3)7, OT4b.31, and CBAM5]. This suggests that a combination of these strains shows strong dual potential for biological control of mosquitos in heavy metal-contaminated areas and remediate the heavy metal contamination as well.

Jilinibacillus soli gen. nov., sp. nov., a novel member of the family Bacillaceae.

A Gram-positive, aerobic, rod-shaped, motile, endospore-forming bacterium, designated strain A12(T), was isolated from a saline and alkali soil samples in Baicheng City, western of Jilin Province, China. Growth occurred in 15-45 °C (optimum, 30 °C) and at pH 7.0-11.5 (optimum, pH 9.0) and in the presence of 0-10 % (w/v) NaCl [optimum, 1-3 % (w/v) NaCl]. Meso-DAP was present in the peptidoglycan. The predominant menaquinone was MK-7. The major polar lipid profile was phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidyl inositol-methyl and phosphotidylinositol dimannosid. The major fatty acid (>10 % of total fatty acids) was anteiso-C15:0. DNA G + C content was 36.2 mol %. The level of 16S rRNA gene sequence similarity between strain A12(T) and other recognized species of the family was below 95.6 %. Phylogenetic analysis based on 16S rRNA gene sequence data indicated that the strain A12(T) fell with the family Bacillaceae and formed a distinct taxon. Based on physiological, chemotaxonomic and phylogenetic analyses, strain A12(T) was considered to represent a novel species of a new genus, for which the name Jilinibacillus soli gen. nov., sp. nov. was proposed. The type strain of Jilinibacillus soli was A12(T) (=GIMN1.014(T) = CCTCC M2011164(T) = KCTC 33417(T)).

Identification of chondroitin-like molecules from biofilm isolates Exiguobacterium indicum A11 and Lysinibacillus sp. C13.

AIMS: The study aims to investigate whether the bacteria from biofilms can produce chondroitin-like molecules (CLMs). METHODS AND RESULTS: Chondroitin belongs to the class of glycosaminoglycans. Forty bacteria from biofilms were isolated and screened for the production of glycosaminoglycans. Two isolates A11 and C13 produced 43 and 26 mg l(-1) of chondroitinase AC II degradable glycosaminoglycans, respectively, suggesting the possibility of production of CLMs by them. These isolates were identified using 16S rDNA sequencing technique and fatty acid methyl ester analysis. These were recognized as Exiguobacterium indicum A11 (NCIM 5531) and Lysinibacillus sp. C13 (NCIM 5532) respectively. These strains were also characterized using polar lipid content and biochemical tests. The identity of the glycosaminoglycans produced was further confirmed using agarose gel electrophoresis, fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy. CONCLUSIONS: Prokaryotic biofilms were found to be a good source of bacteria synthesizing CLMs. Two wild strains producing significant amount of the same were identified and characterized. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study exploring natural biofilms for the production of the therapeutic molecule, chondroitin/glycosaminoglycan. These isolates may be prospective new alternatives to recombinant strains that are reported for the production of chondroitin/glycoaminoglycan at an industrial scale. The production by these wild strains could be commercially attractive if the production is higher and/or can be improved further by strain improvement/process engineering. Further, these are new additions to the scientific literature on glycosaminoglycan-producing micro-organisms.

Oceanobacillus damuensis sp. nov. and Oceanobacillus rekensis sp. nov., isolated from saline alkali soil samples.

Two moderately halophilic strains, PT-11(T) and PT-20(T), were isolated from saline alkali soil samples collected in Shache County, Xinjiang Province, China. Both strains are aerobic, Gram-positive, motile rods. Strain PT-11(T) grows at 15-40 °C and at pH 6.5-10.0, while PT-20(T) grows at 15-40 °C and at pH 6.5-11.0. The major cellular fatty acids in both strains include anteiso-C15:0, anteiso-C17:0 and iso-C15:0. For both strains, the polar lipids consist of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid and several unidentified lipids. In addition, strain PT-20(T) also contains phosphatidylcholine. The major isoprenoid quinone for both strains is MK-7. The genomic G+C content is 36.7 % for PT-11(T) and 39.2 % for PT-20(T). Phylogenetic analyses of 16S rRNA gene sequences indicated that these two isolates are members of the genus Oceanobacillus. DNA-DNA hybridization indicated that strains PT-11(T) and PT-20(T) should be considered two distinct species. On the basis of both phylogenetic and chemotaxonomic data analyses, therefore, we conclude that PT-11(T) and PT-20(T) represent two novel species within the genus Oceanobacillus, for which we propose the names Oceanobacillus rekensis sp. nov. and Oceanobacillus damuensis sp. nov., respectively. The type strains are PT-11(T) (=KCTC 33144(T) = DSM 26900(T)) and PT-20(T) (=KCTC 33146(T) = DSM 26901(T)).

Lentibacillus garicola sp. nov., isolated from myeolchi-aekjeot, a Korean fermented anchovy sauce.

A Gram-stain positive, aerobic and moderately halophilic bacterium, designated strain SL-MJ1(T), was isolated from myeolchi-aekjeot, a Korean traditionally fermented anchovy sauce. Cells were observed to be non-spore-forming rods showing oxidase-negative and catalase-positive reactions. Growth of strain SL-MJ1(T) was observed at 15-40 °C (optimum, 30 °C) and pH 6.5-8.0 (optimum, pH 7.0) and in the presence of 0-20 % (w/v) NaCl (optimum, 6 %). Chemotaxonomic data (major isoprenoid quinone: menaquinone-7; DNA G + C content: 42.8 mol%; cell wall type: meso-diaminopimelic acid; major fatty acids: anteiso-C15:0, anteiso-C17:0 and iso-C16:0) support the affiliation of the isolate to the genus Lentibacillus. Phosphatidylglycerol, diphosphatidylglycerol and an unidentified phospholipid were identified as the major cellular polar lipids. Comparative 16S rRNA gene sequence analysis showed that strain SL-MJ1(T) is most closely related to Lentibacillus juripiscarius IS40-3(T) with a 95.3 % similarity. Phylogenetic analysis based on 16S rRNA gene sequences also support the conclusion that strain SL-MJ1(T) forms a phylogenetic lineage with members of the genus Lentibacillus within the family Bacillaceae. Given its phylogenetic, phenotypic and chemotaxonomic features, we conclude that strain SL-MJ1(T) represents a novel species of the genus Lentibacillus, for which the name Lentibacillus garicola sp. nov. is proposed. The type strain is SL-MJ1(T) (=KACC 18130(T) = JCM 30131(T)).

Omics profiles used to evaluate the gene expression of Exiguobacterium antarcticum B7 during cold adaptation.

BACKGROUND: Exiguobacterium antarcticum strain B7 is a Gram-positive psychrotrophic bacterial species isolated in Antarctica. Although this bacteria has been poorly studied, its genome has already been sequenced. Therefore, it is an appropriate model for the study of thermal adaptation. In the present study, we analyzed the transcriptomes and proteomes of E. antarcticum B7 grown at 0°C and 37°C by SOLiD RNA-Seq, Ion Torrent RNA-Seq and two-dimensional difference gel electrophoresis tandem mass spectrometry (2D-DIGE-MS/MS). RESULTS: We found expression of 2,058 transcripts in all replicates from both platforms and differential expression of 564 genes (absolute log2FC≥1, P-value<0.001) comparing the two temperatures by RNA-Seq. A total of 73 spots were differentially expressed between the two temperatures on 2D-DIGE, 25 of which were identified by MS/MS. Some proteins exhibited patterns of dispersion in the gel that are characteristic of post-translational modifications. CONCLUSIONS: Our findings suggest that the two sequencing platforms yielded similar results and that different omic approaches may be used to improve the understanding of gene expression. To adapt to low temperatures, E. antarcticum B7 expresses four of the six cold-shock proteins present in its genome. The cold-shock proteins were the most abundant in the bacterial proteome at 0°C. Some of the differentially expressed genes are required to preserve transcription and translation, while others encode proteins that contribute to the maintenance of the intracellular environment and appropriate protein folding. The results denote the complexity intrinsic to the adaptation of psychrotrophic organisms to cold environments and are based on two omic approaches. They also unveil the lifestyle of a bacterial species isolated in Antarctica.

Adaptive response of Amphibacillus xylanus to normal aerobic and forced oxidative stress conditions.

Amphibacillus xylanus grows at the same rate and with the same cell yield under aerobic and anaerobic conditions. Under aerobic conditions, it exhibits vigorous oxygen consumption in spite of lacking a respiratory system and haem catalase. To understand the adaptive response of A. xylanus to oxidative stresses, a genomic analysis of A. xylanus was conducted. The analysis showed that A. xylanus has the genes of four metabolic systems: two pyruvate metabolic pathways, a glycolytic metabolic pathway and an NADH oxidase (Nox)-AhpC (Prx) system. A transcriptional study confirmed that A. xylanus has these metabolic systems. Moreover, genomic analysis revealed the presence of two genes for NADH oxidase (nox1 and nox2), both of which were identified in the transcriptional analysis. The nox1 gene in A. xylanus was highly expressed under normal aerobic conditions but that of nox2 was not. A purification study of NADH oxidases indicated that the gene product of nox1 is a primary metabolic enzyme responsible for metabolism of both oxygen and reactive oxygen species. A. xylanus was successfully grown under forced oxidative stress conditions such as 0.1 mM H2O2, 0.3 mM paraquat and 80 % oxygen. Proteomic analysis revealed that manganese SOD, Prx, pyruvate dehydrogenase complex E1 and E3 components, and riboflavin synthase ß-chain are induced under normal aerobic conditions, and the other proteins except the five aerobically induced proteins were not induced under forced oxidative stress conditions. Taken together, the present findings indicate that A. xylanus has a unique defence system against forced oxidative stress.

Oceanobacillus aidingensis sp. nov., a moderately halophilic bacterium.

Two Gram-positive, rod-shaped moderately halophilic bacterial strains, designated AD7-25(T) and AB-11, were isolated from Aiding and Manasi salt lakes in Xinjiang of China, respectively. The strains were found to be able to grow at NaCl concentrations of 0-21 % (w/v), with optimum growth occurring at 6-8 % (w/v) NaCl. The optimal temperature and pH for growth were determined to be 33-37 °C and pH 7.0-7.5. Cells of the strains are motile by means of polar flagella. Both strains can produce ellipsoidal spores. The major cellular fatty acids were identified as anteiso-C15:0, iso-C15:0, iso-C14:0, anteiso-C17:0 and iso-C16:0. The diamino acid in the peptidoglycan and the major quinone system were determined to be meso-diaminopimelic acid (meso-DAP) and MK-7, respectively. The DNA G+C contents of stains AD7-25(T) and AB-11 were 39.8 and 40.0 mol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that these two novel strains are closely related to the genus Oceanobacillus showing 90-99.5 % similarity with respect to type strains. These two novel strains were most closely related to Oceanobacillus oncorhynchi subsp. incaldanensis DSM 16557(T) (99.1 and 99.5 %), followed by O. oncorhynchi subsp. oncorhynchi JCM 12661(T) (99.1 and 99.4 %), Oceanobacillus neutriphilus CGMCC 1.7693(T) (97.0 and 97.5 %), Oceanobacillus sojae JCM 15792(T) (97.6 and 98.0 %) and Oceanobacillus locisalsi KCTC 13253(T) (96.5 and 96.9 %). The DNA-DNA hybridization data indicated that DNA relatedness between strains AD7-25(T) and AB-11 was 91.0 %, and the genomic homology of representative strain AD7-25(T) with O. oncorhynchi subsp. incaldanensis DSM 16557(T), O. oncorhynchi subsp. oncorhynchi JCM 12661(T), O. neutriphilus CGMCC 1.7693(T), O. sojae JCM 15792(T) and O. locisalsi KCTC 13253(T) were 41, 39, 20, 23 and 17 %, respectively. On the basis of phenotypic and phylogenetic distinctiveness, strains AD7-25(T) and AB-11 should be assigned to the genus Oceanobacillus as a new species, for which the name Oceanobacillus aidingensis sp. nov. was proposed. The type strain is AD7-25(T) (=CGMCC 1.9106 (T) = NBRC 105904(T)).

Oceanobacillus halophilum sp. nov. isolated from a mangrove forest soil.

A halophilic, aerobic bacterium, designated GD01(T), was isolated from a mangrove forest soil near the South China Sea. Cells of strain GD01(T) were Gram staining positive, oxidase positive, and catalase positive. The strain was rod shaped and motile by means of peritrichous flagella and produced ellipsoidal endospores. The strain was able to grow with NaCl at concentrations of 0.5-12 % (optimum 3-5 %, w/v), at temperatures of 20-50 °C (optimum 30 °C), and at pH 6.0-8.5 (optimum pH 7.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain GD01(T) formed a cluster with O. profundus DSM 18246(T) (96.4 % 16S rRNA gene sequence similarity), O. caeni KCTC 13061(T) (95.4 %), and O. oncorhynchi JCM 12661(T) (94.5 %). The G+C content of strain GD01(T) was 38.7 mol%. The major respiratory quinone was MK-7. The major cellular fatty acids (>5 %) were anteiso-C15:0, iso-C16:0 (13.7 %), anteiso-C17:0 (12.6 %), iso-C15:0 (9.9 %), iso-C14:0 (9.5 %), and C16:0 (5.0 %). The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, glycolipid, four unknown lipids, and four unknown phospholipids. Based on phenotypic characteristics, chemotaxonomic features, and phylogenetic analysis based on 16S rRNA gene sequences, the strain was identified to represent a distinct novel species in the genus Oceanobacillus, and the name proposed is Oceanobacillus halophilum sp. nov. with type train GD01(T) (=CCTCC AB 2012863(T) = KCTC 33101(T)).