Abstract:[Objective] A halophilic archaeal strain YJ-41^T was isolated from Yangjiang marine solar saltern in the south region of China. In the present work, strain YJ-41^T was characterized in detail to elucidate its taxonomic position. [Methods] The taxonomic status of strain YJ-41^T was studied by using a polyphasic taxonomic method including determining phenotype, chemotype and genotype. [Results] Cells of strain YJ-41^T were rod-shaped, Gram-staining negative and formed red-pigmented colonies on agar plates. Strain YJ-41^T was able to grow between 20 and 50 ℃ (optimum 37 ℃), 2.1 to 4.8 mol/L NaCl (optimum 3.1 mol/L), 0 to 1.0 mol/L MgCl₂ (optimum 0.05 mol/L) and pH 5.0 to 9.0 (optimum 7.0). Cells lysed in distilled water, and the minimal NaCl concentration required to prevent cell-lysis was 10% (W/V). The major polar lipids of the strain were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and eight glycolipids; three of these glycolipids chromatographically identical to sulfated mannosyl glucosyl diether, galactosyl mannosy glucosyl diether and mannosyl glucosyl diether. The 16S rRNA and rpoB' genes of strain YJ-41^T were phylogenetically related to the corresponding genes of Halolamina members (97.5% to 98.4% and 93.1% to 94.4% similarities, respectively). The DNA G+C content of strain YJ-41^T was 61.4 mol%. [Conclusion] The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YJ-41^T (=CGMCC 1.12859^T=JCM 30237^T) represents a new species of Halolamina, for which the name Halolamina litorea sp. nov. is proposed.

Abstract:[Objective] A novel Celeribacter strain NH195^T was isolated from seawater of the South China Sea and was subjected to polyphasic taxonomic study. [Methods] Phenotypic, genotypic and chemotaxonomic characterizations, as well as phylogenetic inference were performed in this study. [Results] Strain NH195^T was a Gram-stain-negative, aerobic, rod-shaped, non-motile bacterium that accumulates poly-β-hydroxybutyrate (PHB). The isolate grew in media containing 0.5%-10.0% (W/V) NaCl (optimally at 1.0%-3.0%) at 20-40 ℃ and pH 5.0-9.0, and was positive for oxidase, catalase and urease. The respiratory quinone was Q-10. The major fatty acids (>10%) were C_18:1ω7c, C_18:1ω6c and 11 methyl C_18:1ω7c. The major polar lipids were phosphatidylcholine (PC), phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), one unidentified aminolipid and two unidentified lipids. The genomic DNA G+C content was 61.3 mol%. Phylogenetic analysis based on the 16S rRNA gene sequences indicated that strain NH195^T could be assigned to the genus Celeribacter. The 16S rRNA gene sequence similarities between the isolate and the type strains of Celeribacter species with validly published names were in the range 94.4%-97.7%. Strain NH195^T exhibited average nucleotide identity (ANI) values of 78.6% and 78.0% to C. halophilus ZXM137^T and C. indicus P73^T respectively. The genome-to-genome distance analysis revealed that strain NH195^T shared 26.1% DNA relatedness with C. halophilus ZXM137^T and 23.0% with C. indicus P73^T, respectively. [Conclusion] On the basis of phenotypic and genotypic characteristics, strain NH195^T represents a novel species within the genus Celeribacter, for which the name Celeribacter ethanolicus is proposed. The type strain is NH195^T (=CGMCC 1.15406^T=JCM 31095^T).

Abstract:[Objective] The aim of this study was to identify a moderately halophilic bacterium, strain BZ-SZ-XJ39, isolated from a saline-alkaline lake in Xinjiang Uyghur Autonomous Region of China. [Methods] On the basis of bacterial morphology and cultivation, biochemical characteristics, analysis of fatty acids, menaquinone and polar lipids, phylogenetic features of 16S rRNA gene sequence, and determination of (G+C) mol% content, the microbiological characteristics of strain BZ-SZ-XJ39 was described. [Results] Phylogenetic analysis based on 16S rRNA gene sequences shows that strain BZ-SZ-XJ39 represented a member of the genus Bacillus. Based on 16S rRNA gene sequence similarity analysis, the closest relatives were B. saliphilus 6AGT (sequence similarity 97.5%), B. daliensis DLS13^T (96.5%), B. luteus JC167^T (96.2%), B. chagannorensis CG-15^T (95.5%) and B. agaradhaerens DSM 8721T (95.3%). This isolate was Gram-staining-positive, non-motile and short rod-shaped. It had yellow colonies and grew with an optimum of 8% NaCl (range 0.5%–28%), at pH 8.0 (range pH 5.5–9.5), and at 33 ℃ (range 4–41 ℃). The dominant fatty acids were anteiso-C_15:0 (50.2%) and anteiso-C_17:0 (16.3%). The polar lipid patterns comprised phospholipid (PL), phosphatidyl ethanolamin (PE), phosphatidyl glycerol (PG), diphosphatidyl glycerol (DPG) and sulfo quinovosyl diacyl glycerol (SQDG) and the main respiratory quinones was Menaquinone 7 (MK-7). The genomic DNA G+C content was 44.4 mol%±1.2 mol% (T_m). The strain was designated as BZ-SZ-XJ39 (CGMCC1.12936, JCM30194). The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain BZ-SZ-XJ39 is KP456019. [Conclusion] On the basis of phenotypic, chemotaxonomic and phylogenetic features, strain BZ-SZ-XJ39 could be a potential novel species within the genus Bacillus. This study will provide a new material of the boundaries for life under high-saline environmental conditions, and will also offer new insight into potential biotechnology applications.

Abstract:[Objective] The objective of this study was to apply multilocus sequence analysis (MLSA) to evaluate the phylogenetic relationship among highly similar strains of the genus Streptomyces isolated from the Indian Ocean sediment samples under the depth of 3 000 m, based on 16S rRNA, atpD, recA and rpoB genes, and to further explore the potential of isolated Streptomyces species. [Methods] We cultured 7 strains of Streptomyces albidoflavus, 11 strains of Streptomyces cavourensis, 16 strains of Streptomyces pratensis isolated from the Indian Ocean deep-sea sediments. We used PCR amplification and sequenced the genes 16S rRNA, atpD, recA and rpoB from these strains and also downloaded 5 strains sequences of S. pratensis from NCBI. We used all sequences to find the gene types in MLST web site and to build the phylogenetic trees for comparison. [Results] After comparison of S. pratensis, the same genotype strains were not clustered together in phylogenetic tree based on 16S rRNA gene sequence, the tree was not stable and degree of differentiation was also low, the phylogenetic trees based on atpD, recA, rpoB genes were relatively stable. Strains in the phylogenetic tree based on multiple gene cluster analysis divided into six groups. In Multilocus sequence analysis of the three Streptomyces, the degree of differentiation increased and the phylogenetic tree was more stable and also found some special strains of recA gene. [Conclusion] Multilocus sequence analysis can divide experimental strains into different types and some strains have large differences in individual gene (recA gene). Multilocus sequence analysis is suitable for classification and identification of some closely related species.

Abstract:[Objective] The objectives are to identify a parasitic Lecanicillium W. Gams & Zare of tea lesser leafhopper and optimize sporulation culture condition of this fungus. [Methods] The comparison of morphological characteristics and internal transcribed spacer (ITS) sequence analysis were used for identification of the fungal species. Single factor test and orthogonal test were carried out to optimize sporulation conditions. [Results] According to the morphological characterization and phylogenetic tree, the fungus was identified as Lecanicillium attenuatum Zare & W. Gams. The optimum condition of or sporulation is: peptone 2%, maltose 1%, silkworm pupa powder 1%, potassium chloride 0.05%, dipotassium phosphate 0.1%, magnesium sulfate 0.05%, agar 1.5%, distilled water 1 000 mL, 25 ℃. [Conclusion] A parasitic Lecanicillium of tea lesser leafhopper is identified as L. attenuatum Zare & W. Gams, a known species in China. The optimum condition of sporulation was providedons, which could provide the preliminary basis for applying to the tea lesser leafhopper of the biological control.

Abstract:[Objective] Fungi are found everywhere and associated closely with human life. Identification of fungi is the basis of further scientific research and commercial application of fungal resources. In this study, 112 fungal strains preserved at the Agricultural Culture Collection of China (ACCC) were randomly chosen to test the application of rDNA internal transcribed spacer (ITS) sequences in their identification at the genus level. [Methods] rDNA ITS was sequenced from all the strains used in this study and compared with available sequences in GenBank using a BLASTn search for their generic identification. [Results] Among the strains used, 80 were consistent with their original generic determinations. Polymorphisms of DNA bases or impurity of sequence chromatograms reduced the similarity in comparison with the target sequence in GenBank. [Conclusion] rDNA ITS sequences can be used for confirmation of fungal strain identity at the level of genus. It is recommended that all the fungal strains prior to and in preservation in national microorganism collections should be checked through rDNA ITS sequence analysis and the name of strains should be treated with caution. The original determination and the history of used names of each strain should be kept in the database for further reference.

Abstract:[Objective] To characterize a novel Pseudomonas aeruginosa phage PaP6 via its biological properties. [Methods] Double-layer agar culture method was applied to observe the plaques of PaP6. Phage particles were examined by electron microscopy after cesium chloride density gradient centrifugation. PaP6 genome was extracted and digested with either DNase or RNase. Phage and host were mixed with multiplicity of infection (MOI) 10, 1, 0.1, 0.01, 0.001 and 0.000 1 respectively. Phage titers were measured after bacteria lysis. For one step growth experiments, phage and host with an MOI of 10 were used. The host range of PaP6 was tested with 112 Pseudomonas aeruginosa clinical isolates strains. [Results] The plaque of PaP6 was transparent and the edge of the plaque was clear. Its diameter was about 2 to 4 mm. PaP6 phage had an isometric head approximately 45 nm in diameter. Enzyme digestion experiment shows that PaP6 contained three double-stranded RNA segments. Infecting host bacteria with MOI of 0.1 gave the highest phage offspring. Phage growth characteristics were determined by one step growth curve. PaP6 infects 40.1% of Pseudomonas aeruginosa clinical isolated strains. [Conclusion] PaP6 genome is composed of three dsRNA segments, and it is the first reported Cystoviridae phage that infects Pseudomonas aeruginosa. The host range of PaP6 is wide, which implies its potential in phage therapy.

Abstract:[Objective] The main focus for the current study is to investigate the diversity of culturable bacteria in soils of karst caves located in Xingyi county of Guizhou province and to analyze their potential for production of protease and amylase. [Methods] Isolation of the culturable bacteria was done by spread plate technique using 11 synthetic media. Phylogenetic relationship of the isolates based on their 16S rRNA gene sequences was analyzed. The isolates were then screened for production of protease and amylase using plate method. [Results] Based on the 16S rRNA gene sequences, a total of 217 isolates affiliated to 63 species of 24 genera were determined, of which the genera Rhodococcus and Streptomyces were the dominant bacteria (comprising 24.42% and 21.66% respectively). Majority of these strains had 16S rRNA gene sequence similarities ranging between 97.90% and 99.99% with related type strains, except the strains D3T01, D911, D961 and D502 which are potential new taxa. Of these culturable bacteria isolated, 99 strains belonging to 38 species of 18 genera were positive for protease and/or amylase activities. Among these, 36 strains had both amylase and protease activities, thus constituting about 36.36% of the bioactive strains and 16.59% of the total isolates. [Conclusion] The results indicated that soil of karst caves in southwest of Guizhou are promising sources for isolation of many bioactive strains, with potential for further exploration and research.

Abstract:[Objective] Polycyclic aromatic hydrocarbons (PAHs) are known as high-toxic and persistence organic contaminants in the environment. Screening highly efficient degrading bacteria is important for bioremediation of PAHs-contaminated environment. This study aimed to isolate and identify high efficient PAHs-degrading bacteria from the candidate strains, then to characterize degrading properties of these target strains. [Methods] PAHs-degrading bacteria were screened by the plate-culture method, and then these target strains were identified by the 16S rRNA gene phylogenic analysis. Degrading properties of PAHs-degrading bacteria were determined by single factor experiments. [Results] Three PAHs-degrading bacterial strains SL-1, 02173 and 02830, which utilized phenanthrene and pyrene as the sole carbon and energy source for growth, were obtained from the candidate strains. The strain SL-1 was the type strain of Rhizobium petrolearium. 02173 and 02830 were highly homologous to Pseudomonas alcaliphila and Pseudomonas corrugate, respectively. The strain SL-1 could degrade 100% of single phenanthrene (100 mg/L) and 48% of single pyrene (50 mg/L) in 3 days, and the degradation rate of pyrene was up to 74% in 5 days; it also could degrade 75.89% and 81.98% of mixed phenanthrene and pyrene within 3 days. The strain 02173 and 02830 could degrade a mixture of PAHs completely in 3 days, including naphthalene (200 mg/L), fluoranthene (50 mg/L), phenanthrene (100 mg/L) and pyrene (50 mg/L). [Conclusion] Three PAHs-degrading bacterial strains SL-1, 02173 and 02830 have high-efficient degradation ability not only for low-molecular-weight PAHs but also high-molecular-weight PAHs. These strains were the ideal candidates for bioremediation of PAHs-contaminated environment. Low-molecular-weight PAHs can promote high-molecular-weight PAHs degradation due to con-metabolism effect, while the biodegradation of low-molecular-weight PAHs will be suppressed.

Abstract:[Objective] Investigating the diversity of the cultivable bacteria in Arctic Ocean sediments. [Methods] Culturable bacteria were isolated from marine sediments collected during the 6^th Chinese National Arctic Expedition (Arc6) by marine Zobell 2216E medium and spread plate method. Subsequently, 16S rRNA gene sequence similarity analysis and phylogenetic analysis were performed. [Results] A total of 445 strains were isolated from 40 sediments samples. According to the results of 16S rRNA gene sequence similarity as well as phylogenetic analysis, the isolates belong to 4 phyla, 6 classes, 13 orders, 28 families, 49 genera and 91 species. Twelve isolates having 16S rRNA gene similarity less than 97% with the closest type strain were grouped into 6 independent clusters, implying that these isolates might be six novel species. Our study also indicated that the genus composition of the strains from 6^th Arctic Expedition were strikingly different with that from 5^th Arctic Expedition (Arc5). [Conclusion] There are abundant microbial resources and many novel microbes in Arctic Ocean sediments, and it is to be developed in the treasure house of microorganisms.

Abstract:[Objective] The diversity of lactic acid bacteria in traditional fermented milk from Hulun Buir in Inner Mongolia was studied. [Methods] The samples were analyzed using pure culture and 16S rRNA gene sequence analysis. [Results] A total of 24 strains of lactic acid bacteria were obtained from eight fermented milk samples (6 fermented cow milk and 2 fermented mare milk). All the isolates were classified to 5 genera and 9 species: Lactobacillus kefiranofaciens (2 strains), Lactobacillus kefiri (2 strains), Lactobacillus paracasei (5 strains), Lactobacillus plantarum (3 strains), Lactobacillus rhamnosus (1 strain), Lactococcus lactis subsp. lactis (6 strains), Leuconostoc mesenteroides subsp. dextranicum (2 strains), Streptococcus thermophilus (2 strains), and Enterococcus faecium (1 strain). [Conclusion] Lactococcus lactis subsp. lactis is the dominant species, held 25% of the total isolated lactic acid bacteria, and Lactobacillus paracasei occupied 20.83% of the total lactic acid bacteria isolates as the predominant species of traditional fermented milk from Hulun Buir in Inner Mongolia.

Abstract:[Objective] The cellulose-decomposing strains for corn stalk were screened. [Methods] Agar dilution method was used to screen strains decomposing corn stalks from soil samples. Strains were identified by their morphological, physiological and biochemical properties and internal transcribed spacer sequence analysis. Then we compared the activities of cellulose and lignin degrading enzyme of the isolated strains with that of Penicillium spp. (CICC40361), studied the influence of different factors on cellulase activity, as well as the K_m values of the cellulase. [Results] A strain named PL2# was identified as Penicillium lanosum. The activities of cellulase and lignin enzyme of strain PL2# were higher than that of Penicillium spp. Conditions for optimal enzyme activity of strain PL2# was at 1% of carboxy methyl cellulose concentration, pH 4.8, 50 ℃, enzyme reaction time 60 min and 2 mL of DNS (3,5-dinitrosalicyclic acid) agent. [Conclusion] Strain PL2# (Penicillium lanosum) was better than the control strain Penicillium spp. in the degradation of corn straw cellulose.

Abstract:[Objective] Strains were screened from endophytic resources of soybean root nodules in Henan province against Magnaporthe grisea, and researched its inhibitory effect in order to provide the species resources for further study inhibitory mechanism. [Methods] Taking Magnaporthe grisea as tested pathogens, the endophytic bacteria were characterized by antagonistic tests with confront method, the phytopathogen hyphae were analyzed by microscopic observations, the obvious features of antagonistic strains were determinated by cell morphological observation, physical and biochemistry characteristics, 16S rRNA gene sequencing, phylogenic analysis and biological control effect tests. [Results] A total of 17 strains have obvious antagonitic effect by secondary screening, the highest inhibition rate reach 62.16%. Results of microscopic analysis on pathogen hyphae showed that hyphae appear bend knot, fracture, protoplasm concentration, deformity and so on. Interestingly, endophytes rapidly grew to form biofilms on plate during antagonitic screening, and embed hyphae and make it break. Combined with the colony characteristics, physical and biochemistry characteristics and phylogenetic analysis, antagonistic strains were distributed in seven genera and nine species, so antagonistic endophytic bacteria against rice blast possessed species diversity. Control effect tests suggested that rice seedlings incidence and disease index of treatment group with endophytes are significantly lower, biological control efficiency reach up to 74.19%. [Conclusion] Diverse strains were screened from endophytic resources of soybean root nodules against Magnaporthe grisea, rice seedlings incidence and disease index of treatment group with endophytes are significantly lower, biological control efficiency reach significant, it provided species resources for further study inhibitory mechanism.

Abstract:[Objective] To isolate, screen and identify rice endophytic actinomyces with antagonistic activity against rice blast pathogen, to evaluate the disease control effect of the selected antagonist and to study its potential antagonistic mechanism. [Methods] We used 4 isolation media to isolate endophytic actinomycetes from surface sterilized rice. Using dual culture assay, we screened the strain with antagonistic activity and identified it by morphological, physiological and biochemical characteristics and 16S rRNA gene sequence analysis. We observed the effect of the antagonist on the hyphae of pathogen under scanning electron microscopy and tested the in vitro antagonistic activity of fermentation broth by growth rate method. In field condition, we evaluated the disease control efficiency after spraying the antagonist spore solution on rice. Meanwhile, we analyzed enzymes and secondary metabolites production of the antagonist, and amplified its polyketide synthases (PKSⅡ) and nonribosomal peptide synthetases (NRPS) genes. [Results] From 1 800 rice samples, a total of 117 endophytic actinomycetes were isolated, among which, OsiRt-1 exhibited remarkable antagonistic activity. OsiRt-1 was identified as Streptomyces misionensis. The pathogen Magnaporthe oryzae treated by OsiRt-1 revealed significant morphological alterations in hyphe and its mycelial growth was inhibited by culture filtrates of OsiRt-1 with a percent of 28.06%. In field condition, OsiRt-1 spore solution could reduce seedling blast severity by 7.76%, panicle blast disease severity by 25.65% and lose rate by 17.46%. The separation rate of OsiRt-1 from above-ground portion of rice treated with OsiRt-1 is higher than the not treated ones. Besides, OsiRt-1 is positive for PKSⅡ and NRPS genes and can produce cellulase, protease, siderophore, IAA and ACC deaminase. [Conclusion] Endophytic Streptomyces misionensis OsiRt-1 has the application potential in agriculture as a biocontrol agent against rice blast disease.

Abstract:[Objective] Chitin deacetylase is a key enzyme in the conversion of natural chitin into chitosan, which can be commercially used. The aim of this work is to screen a new strain with high capacity for producing chitin deacetylase. [Methods] Chitin deacetylase producing strains from soils of Xiangjiang riverside in Changsha area were preliminarily screened with chitin as only source of carbon by color reaction of 4'-nitroacetanilide, and further screened by enzyme activity analysis; Identification of strains was analyzed by morphological and internal transcribed spacer (ITS) sequence. [Results] We isolated 117 starins from soils of Xiangjiang riverside, thirty strains had the potential producing chitin deacetylase ability, and among which, four potential strains had the most high capacities, and validation of enzyme activity analysis suggested that strain A1 had the highest capacity for producing chitin deacetylase, the extracellular enzyme activity reached 13.21 U/mL. On the basis of morphological and ITS sequence identification, strain A1 was preliminarily identified as Fusarium proliferatum. [Conclusion] We obtained a F. proliferatum strain isolated from soils of Xiangjiang riverside with high capacity for producing chitin deacetylase.

Abstract:[Objective] This study provides the theoretical basis for optimal cultivation and nutrient utilization of Chorella vulgaris. The study aimed to discuss the effect of varying light intensity (0, 1 000, 3 000, 5 500, 7 000, 9 000 lx) on the growth of Chorella vulgaris. [Methods] The experiment was conducted under aeration rate of 20% and at 20 ℃, and the Chorella vulgaris was cultivated on the BG-11 culture medium under stable condition. Parabolic regression curves between light intensity and the maximum optical density (OD_max) and the maximum growth rate (μ_max) were created. [Results] The growth rates varied different in different light intensity, and the chlorophyll a concentrations increased in the initial time until reached the maximum value and then decreased dramatically. The intensity of 5 500 lx was most suitable for the Chorella vulgaris growth. The demand of phosphorus of algal growth was greater than the nitrogen. [Conclusion] The mathematical relationships between light intensity and OD_max, μ_max simulated by cubic curve equation were shown as follows: OD_max=-1E–07x²+0.001 6x+0.105 5 (R²=0.9872, 0≤x≤9 000 lx), μ_max=-2E–08x²+0.000 3x-0.004 2 (R²=0.998 6, 0≤x≤9 000 lx).

Abstract:[Objective] The study researched the biological characteristics of three Lactobacillus reuteri strains, providing guidance in industrial production. [Methods] We analyzed and compared diverse characteristics and capabilities of three Lactobacillus reuteri strains preserved in the lab, such as growth curve, pH curve, tolerance to artificial gastric intestinal juice, tolerance to porcine bile salt, adhesive capacity, antimicrobial activity, and tolerance to antibiotics. [Results] The growth trend of these 3 strains was similar. All of the 3 strains had a good tolerance to artificial gastric intestinal juice, and could inhibited the growth of Escherichia coli and Staphylococcus aureus effectively. L0 and L2 showed poor tolerance in high porcine bile salt environment, while the performance of L1 was satisfactory. In addition, L1 and L2 had strong adhesive ability and the tolerances of 3 strains to 20 antibiotics were different. [Conclusion] L1 can be further applied in the industrial production since its biological characteristics are significantly better than the other two strains.

Abstract:[Objective] Stability of the yellow pigment from Lachnum sp. was evaluated. [Methods] Taking absorption value at 410 nm of the pigment as an indicator, the effect of temperature, light, pH, reducer, oxidant, metal ions and food additives on the stability of the pigment were investigated. [Results] The yellow pigment could be dissolved in water easily. The yellow pigments solution had each absorption peak in ultraviolet range and visible range and the maximum absorption wavelength were 300 nm and 410 nm, respectively. The preservation rate of the pigment was near 90% after 70 ℃ incubation for 4 h indicating that it was relatively stable to heat. Light resulted in an obvious loss of stability of the pigments. With the increasement of pH, the color of the yellow pigment became dark gradually and the A₄₁₀ of the pigments solution increased. The color of the pigments solution kept stable at pH 9.0-10.0 and the preservation rate was closed to 90% at pH 10.0 for 5 d. The yellow pigments solution was bleached by ascorbic acid and it was resistant to NaNO₂ and H₂O₂. However, it was freshed by Na₂SO₃. The color of the pigments solution was changed by Fe³⁺ and Fe²⁺, Al³⁺, Cu²⁺ and Zn²⁺ could fade the color of the yellow pigment solution, but Ca²⁺, K⁺, Mg²⁺ had a slightly effect on it. Sucrose, glucose, and potassium sorbate had no distinct effects on the stability of the pigment solution. The stability of the pigment solution was slightly influenced by NaCl solution. [Conclusion] The yellow pigment from Lachnum sp. was worthy to be developed for its good stability.

Abstract:[Objective] We cloned, expressed and characterized a novel esterase E29 from a marine bacterium. [Methods] An assumed esterase gene, which was predicted via the genome of Altererythrobacter luteolus SW109^T and amplified by PCR, was cloned into expression vector pSMT3. The recombinant plasmid was transformed into Escherichia coli BL21(DE3). Subsequently, E29 was obtained via heterogenetic expression and characterized. [Results] The amino acids sequence analysis revealed E29 represents a new member of Family II of lipolytic enzyme. According to biochemical characterization, the maximum hydrolysis activity was obtained using p-nitrophenyl butyrate as substrate, at 45 ℃ and pH 8.5. The activity of E29 decreased in solution containing 10 mmol/L Co²⁺ or Mn²⁺, or 15% isopropanol or acetonitrile. The esterase was inactivated in 1% SDS solution. The addition of glycerol can promote the activity of E29 strikingly. [Conclusion] E29 is a novel marine esterase. Due to its high enzyme activity, wide substrates selectivity as well as tolerance of some organic solvents and metal irons, E29 has potential application in industry.

Abstract:[Objective] Exploring the difference of structure, function as well as the genetic diversity of upstream sequences adjoining tuf gene in paulownia and jujube witches'-broom phytoplasmas. [Methods] Thermal asymmetric interlaced PCR (TAIL-PCR) was used to amplify the upstream unknown sequence adjoining tuf gene in jujube witches'-broom phytoplasma. Recombinant expression system was successfully constructed with promoter-probe vector pSUPV4 and tuf gene upstream sequences from paulownia and jujube witches'-broom phytoplasma. Genetic variation and promoter activity of tuf gene upstream regulatory sequences from 16SrI group phytoplasma strains including paulownia witches'-broom, chinaberry witches'-broom, lettuce yellows, mulberry dwarf and periwinkle virescence phytoplasma strains and 16SrV group strains including jujube witches'-broom, cherry lethal yellow, Bischofia polycarpa witches'-broom phytoplasma strains were analyzed and identified. [Results] The sequence length of intergenic region between tuf and its upstream gene, fusA, in 16SrI group strains was 129 to 130 bp, with putative complete promoter conservative structure. 130 bp upstream sequence of tuf gene in paulownia witches'-broom phytoplasma had promoter activity. There were four variation types in the intergenic region sequences from five kinds of 16SrI group phytoplasmas including 35 strains; the sequence length of intergenic region between fusA and tuf in 16SrV group strains was 53 to 54 bp, with predicted incomplete promoter structure. No promoter activity was found in 144 bp and 346 bp upstream sequence of tuf gene in jujube witches'-broom phytoplasma. There were two variation types in the intergenic region sequences from three kinds of 16SrV group phytoplasmas including 20 strains. The fusA-tuf intergenic region sequences were comparatively conservative, and the phytoplasma strains belonging to different groups were distinguished clearly by the phylogenetic tree constructed based on the sequences. [Conclusion] The methods and results of the study would lay a beneficial foundation in further investigating phytoplasma gene expression and regulation, revealing phytoplasma regularity of growth and propagation as well as its pathogenicity mechanism.

Abstract:微生物资源是国家战略性生物资源之一,是支撑微生物学科发展与技术创新的重要基础。中国作为微生物资源的大国,近年来,通过“国家微生物资源平台”项目的建设,在微生物资源的分离、收集、保藏与共享等方面都取得了较大的发展。在我国微生物资源科技工作者的共同努力下,微生物新种的分离与发表也跃居世界首位。《微生物学通报》组织了本期“微生物资源”主题刊,旨在展示微生物资源学领域的最新进展,加强微生物资源学领域学术交流,提升我国微生物资源分类和系统学研究水平,促进微生物资源学科发展,推进国家微生物资源平台建设。

Abstract:2015年8月,“第七届全国微生物资源学术暨国际微生物系统与分类学研讨会”在浙江省杭州市顺利召开。会议重点围绕微生物资源与分类领域的新技术、新方法和新进展开展学术研讨与交流,展示了我国微生物资源与分类领域的研究水平和发展前景;会议特别举办了“微生物系统与分类学”专题培训。“微生物资源学术研讨会”与《微生物学通报》首次合作,出版了一期“微生物资源”主题刊,在微生物新分类单元有效发表方面做了有益探索,期望该期论文集有助于促进我国微生物资源与分类领域的交流和发展。

Abstract:

Abstract:The genus Clostridium as presently constituted is phylogenetically and phenotypically incoherent. Polyphasic taxonomic data indicate that the genus comprises a collection of very heterogeneous species. Numerous phylogenetic studies, principally based on sequencing of the 16S rRNA gene, indicate that the genus Clostridium should be restricted to Clostridium cluster I as Clostridium sensu stricto. Despite these findings, authors continue to add new species to the genus Clostridium that do not fall within the radiation of cluster I and the type species C. butryicum thus perpetuating the confusion associated with the taxonomy of this group. Here I formally propose that members of the Clostridium (Prazmowski) be restricted to the type species Clostridium butyricum and cluster I species. Eubacterium moniliforme, Eubacterium tarantellae, Sarcina maxima, and Sarcina ventriculi should be transferred to the genus Clostridium as Clostridium moniliforme comb. nov., Clostridium tarantellae comb. nov., Clostridium maximum comb. nov., and Clostridium ventriculi comb. nov. A novel genus Hathewaya gen. nov. is proposed for the species Clostridium histolyticum, Clostridium limosum and Clostridium proteolyticum as Hathewaya histolytica gen. nov. com. nov., Hathewaya limosa com. nov. and Hathewaya proteolytica comb. nov. The type species of Hathewaya is Hathewaya histolytica.

Abstract:Concerning the present microbiological knowledge system, we can only isolate and culture a small fraction of microbes with the existing microbial culture techniques, leaving the vast majority of microorganisms in the natural environment unculturable. This article summarizes some microbial cultivation techniques and strategies, including space separation, prolongation of cultivation, and simulation of the natural environmental conditions. Much attention is paid to the effects of the medium nutrient levels on microbial culturability. This article also briefly summarizes the physiology and ecology of oligotrophic bacteria, as well as how nutrient concentration affects microbial growth. It is proposed that microbial culturability would be improved via rational design of culture medium and applying proper culture conditions.

Abstract:Erythrobacteraceae belongs to the domain Bacteria, phylum Proteobacteria, class Alphaproteobacteria order Sphingomonadales. It was proposed in 2005 and included 3 genera, for a total of 5 species based on phylogenetic analysis of 16S rRNA genes. As of October 2015, the family Erythrobacteraceae includes 44 species with validly published names in 6 genera. Members of the family Erythrobacteraceae are widely distributed in soil, hot springs, sea water or sediments environments as well as other ecosystems. They have great potentials in pollution bioremediation, food engineering and biological pharmacy. In addition, some members of the Erythrobacteraceae contain bacteriochlorophyll α and are classified as aerobic anoxygenic phototrophic bacteria, which play an important role in carbon cycling and energy metabolism in marine environments and have gradually become a research hotspot. This paper reviews the progress in the study of their taxonomic characteristics, ecological diversity, fundamental research for application of the family, and also illuminates future research directions.

Abstract:Originally, rhizobia refer to the legume-nodulating symbiotic Gram-negative bacteria, belonging to Class Alpha- and Beta-proteobacteria in Phylum Proteobacteria. Recently, the developments in systematic technology of bacteria and the studies of more novel isolates have greatly changed the taxonomy of rhizobia. In the newest classification, some species in the genus Rhizobium within Class Alphaproteobacteria have been reclassified: several species were maintained in Rhizobium, while two novel genera, Pararhizobium and Neorhizobium, were proposed. In addition, two genera Agrobacterium and Allorhizobium were restored and re-amended. Both symbiotic and nonsymbiotic bacteria were included in these genera. Though the name of Sinorhizobium in Class Alphaproteobacteria has been replaced by Ensifer, the former is still being used widely especially in the studying of symbiotic bacteria. In relation to the systematic methodology, the most important development in the last decade is that whole genomic sequencing and average nucleotide identity (ANI) have been applied to replace the traditional DNA relatedness. Because of the higher conservation of 16S rRNA gene sequence in rhizobial phylogeny, it is usually used in determining the phylogenetic position in the level of genus. Combination of multilocus sequence analysis (MLSA) and whole genome sequencing ANI is now the “Gold Standard” for the definition of bacterial genospecies. Together with the rapid determination of phenotypic features, including biochemical characters, fatty acids and quinones, the systematics of rhizobia developed rapidly in the last decade. In future, the classification system of rhizobia based upon the sequence analysis of whole genome will be more stable, while novel species in some defined genera or corresponding to some new genera will be described when more nodule isolates are studies. Furthermore, the finding of symbiotic promiscuity between Sophora flavescens, a kind of medicinal legume, and various rhizobia harboring distinct nodulation genes, completely broke the knowledge of symbiotic specificity, facilitating the reconsideration of the symbiotic relationship between legumes and rhizobia.

Abstract:Thermophiles, including moderate thermophiles and extreme thermophiles, mainly survive in natural geothermal environments, such as hot springs, volcanic vents and submarine hydrothermal vents, and artificial high temperature environments like reactors or wastewater discharge ports with high temperature. Thermophiles can grow at temperature of 40-80 ℃ and above. Many of them are acidophilic and have specific metabolism types, which endow them to be used into the high temperature-biomining processes. Biomining processes under high temperature show more advantages than traditional mesothermal biomining process, which can effectively leach out some of the refractory primary sulfide minerals, resolve passivation problem, therefore improve leaching rate. In this review, we summarized the physiological characteristics of main thermophiles used in biomining processes and their resistance mechanisms on high temperature, iron, copper, arsenic and other ions, furthermore, the developments and applications of thermophiles in biomining technology were presented.

Abstract:Halophilic archaea are archaea required high concentrations of salt for growth. Up to date, all the halophilic archaea belong to the phylum Euryarchaeota of the domain Archaea. Currently, halophilic archaea consist of halophilic methanogenic archaea, all members of the class Halobacteria and uncultured “Nanohaloarchaea”. Halophilic archaea are the native microorganisms inhabited in saline environments, which involved in various biogeochemical cycles in saline ecosystem. As a group of extremophiles, halophilic archaea were involved in the theoretical and applied researches. From the aspects of the taxonomic status change, taxonomic methods, current status and the taxonomic study of halophilic archaea in China, the recent advances in the classification and identification of halophilic archaea were summarized in this review.

Abstract:The genus Nocardiopsis has classical filamentous mycelium differential characterization. In the last decade, studies on this genus have got much attention and undergone fast developments. Until now, this genus comprises of 42 species and 2 subspecies reported. Members of the genus Nocardiopsis are widely distributed in soil, especially natural hyper saline or alkaline samples, marine habitats, clinical specimen as well as other ecosystems. Recently, researchers have isolated many bioactive metabolites from various strains in this genus, including antibiotics, enzyme inhibitors, immune regulators and biosurfactants, as well as enzymes, which have great potentials in pharmaceutical agents and biotechnology. This paper reviews the research progress of taxonomic studies, ecological diversity, adaptive mechanism, metabolites and genetic transformation of the genus, and also proposes the future directions.

Abstract:The science of bacterial taxonomy started in late 19th century. The main methods of bacterial classification were simply based on phenotypic markers and physiological-biochemical characteristics then. The appearance of DNA-DNA hybridization and 16S rRNA gene sequence analysis brought a huge improvement to the field. However, recently, more and more studies have demonstrated that these approaches have some drawbacks. Fortunately, the emergence of the genomics technology has brought about novel concepts and insights into this area. This paper introduces the principle and application of five bacterial classification methods that are based on whole genome data, including average nucleotide identity analysis, core genome analysis, maximal unique matches index analysis, K-string composition vector method and genomic fluidity analysis.

Abstract:Methanogen is a group of strictly anaerobic archaea, which can obtain energy for growth by formation of methane from simple compounds. The archaea is most likely linked to the origins and evolution of life on Earth, and plays an important role in global climate change, carbon biogeochemical cycle and resource utilization of agricultural wastes. The comprehensive understanding of biological characteristics of methanogens will promote the basic and applied research. This review summarizes recent studies of methanogens, including the physiological and chemical properties, metabolism pathway, energy conservation and systematic taxonomy.