Abstract:Abstract:Helicobacter pylori (H．pylori) is a gram-negative pathogen that widely colonizes in the human gastric mucosa，and is associated with various gastric diseases．Recently，much attention has been aroused on the relationship between H．pylori infection and autophagy．Accumulating evidence suggests that H. pylori can induce autophagy in gastric epithelial cells and professional phagocytes．Both the virulent factors of H．pylori and host autophagic proteins have been demonstrated to affect H．pylori-induced autophagy．Besides，the process of autophagy plays an important role in determining the intracellular fate of H． pylori．Here，we review the impact of H．pylori infection on autophagy of different cells.

Abstract:Abstract:［Objective］The methanogenic archaea plays many ecological roles in paddy ecosystems such as the regulation of CH4 emissions.However，knowledge gaps exist about the mechanisms of their spatial shift in population.［Methods］We collected 8 latitudinal paddy soil samples from 20.55°N to 47.43°N in China，and studied their methanogenic archaeal community compositions by PCＲ-DGGE fingerprinting and phylogenetic analyses．Mechanism of spatial shift in community composition was unraveled by canonical correspondence analysis and Venn diagram.［Results］Soil pH was one of the main environmental triggers to the composition of methanogenic archaea community in paddy soils．In addition， community composition shifted along latitudinal gradients．［Conclusion］ It is the first report on biogeography of methanogenic archaeal community in arable soils and its environmental driving factors． The information would contribute to understanding spatial shifts in the transformation of organic matters along Chinese latitudinal gradient.

Abstract:Abstract:［Objective］Aim to study the physiology and functionally important genes of Lactobacillus lactis KLDS4. 0325.［Methods］ We sequenced the complete genome of L．lactis KLDS4.0325，drew the genomic map，and performed functional annotation and analysis in metabolism and probiotic.［Results］L．lactis KLDS4.0325 contains a chromosome of 2589261 bp，GC content is 35.4%，with 2662 predicted ORFs，of which 1310 are functionally classified．L．lactis KLDS4.0325 can carry out hydrolysis of extracellular proteins effectively，has the potential to degrade bitter peptides and produce a series of peptides of inhibiting angiotensin converting enzyme．L．lactis KLDS4. 0325 has complete enzyme system for transamination pathway，which can catalyze relevant amino acids to flavor compounds．More key enzyme-coding genes involved in transport and metabolizing of sugars，and L-lactic acid synthesis，are exist in L．lactis KLDS4.0325 genome．L．lactis KLDS4. 0325 has a set of more complete encoding genes in the biosynthetic pathways of folate and riboflavin． In addition，gene cluster for Lactococcin and 2 cold stress protein (cspD and cspE) were identified．［Conclusion］ The presence of these genes encoding desirable traits provides the theoretical basis for the strain in industrial fermentation，and relevant further research.

Abstract:Abstract:［Objective］To investigate the function of gene PA2580 in Pseudomonas aeruginosa PAO1.［Methods］We constructed a PA2580 knockout mutant of PAO1 and a complemented strain of the mutant．We studied the function of the gene PA2580 using both genetic and biochemical methods，including antibiotic minimum inhibition concentration (MIC) comparison，measurement of gene expression levels in different conditions，protein expression and purification in vitro and enzymatic activity detection．［Results］ PA2580 mutant was more sensitive to carbenicillin，chloramphenicol and ciprofloxacin．PA2580 expression was regulated by sub-inhibitory concentrations of antibiotics．PA2580 protein reduced various quinones efficiently using NADPH as the electron donor． PA2580 mutant was more sensitive to hydrogen peroxide and the mutant showed decreased expression of catalase．These results indicate that PA2580 is involved in the tolerance of oxidative stress in P．aeruginosa． ［Conclusion］ The P．aeruginosa PA2580 protein physiologically functions as an NADPH quinone reductase which plays an important role in dealing with environment stress．

Abstract:Abstract:: ［Objective］Purpose of this work was to screen myxobacteria from soils and study their biological activities towards pathogenic bacteria，tumor cells and insects.［Methods］Through inactivated E．coli and filter paper inducing methods，we isolated and purified myxobacteria from soil samples．Then we identified these purified strains based on morphological observation，physiological and biochemical characteristics，and the 16S rDNA sequences homologous analysis．By plate diffusion experiments，oral toxicity tests and tetrazolium assays，we investigated the biological activities of the myxobacterial culturesupernatant.［Results］We isolated 35 myxobacterial strains and classified them as 4 genera: Myxococcus (9)，Corallococcus (9)，Nannocystis (11) and Sorangium (6)．Eight purified myxobacteria were identified and named．Cytotoxicity tests show that strain C.macrospores S22 had potent and broad-spectrum cytotoxic effect on tumor cell lines including B16，4T1，HeLa and HCT-116，so did the strains M．fulvus S51，C．exiguus S22 and M．Xanthus S55． Additionally，C．macrospores S22 also shows inhibitory activity to pathogenic bacteria Bacillus subtillis and Candida albicans．［Conclusion］Myxobacteria are widely distributed in natural soils．C．macrosporus has potent toxicity against cancer cells and pathogenic bacteria; and C．exiguus with antitumor activity．The myxobacterial strains are promising resources for discovery and development of new active natural products and drugs．

Abstract:Abstract:［Objective］ To study the regulation of laeA overexpression on mevastatin production and sporulation in Penicillium citrinum． ［Methods］We cloned the laeA gene from Penicillium citrinum and constructed the vector pGiHTGilaeA．The plasmid pGiHTGi-laeA was transformed in Penicillium citrinum by agrobacterium tumefaciens-mediated transformation．Positive transformants were detected by cloning the hygromycin gene．The mevastatin production of the wild type and OE::laeA was compared by HPLC．The conidia number was counted by blood counting chamber．The biosynthetic gene cluster expression quantity of mevastatin in the wild type and OE::laeA were analyzed by qRT-PCR.［Results］We constructed the plasmid pGiHTGi-laeA，and screened the positive transformants that overexpress the laeA in Penicillium citrinum．With the overexpression of laeA，the mevastatin production was increased from (0.69±0.12)mg/g to (4.02±0.50) mg/g dry cell weight．Compared to the wild type strain，the laeA expression quantity in the OE::laeA strain increased 29%，and the mlcB expression increased 72%，the mlcＲ expression increased 153%． Moreover，the overexpression of laeA would decrease the conidia number．［Conclusion］Overexpression of LaeA enhances mevastatin production and reduces sporulation of Penicillium citrinum，with increases expression of pathway-regulator mlcR，and biosynthetic gene MlcR．These results could guide global regulatory mechanism of mevastatin biosynthesis and the exploitation of high-production strain.

Abstract:Abstract:［Objective］Expression level of laccase POXA1c would be increased by screening effective signal peptide in Pichia pastoris． ［Methods］According to 2D-gel and profile of P． pastoris genome sequence，seven signal peptides from high secreted endogenous proteins of P． pastoris X-33 were chosen to evaluate their secreted ability by using POXA1c as reporter protein.［Results］ Compared with POXA1c’s native signal peptide，the signal peptide of repressible acid phosphatases PHO5 and lectin-like protein FLO10 showed 2. 5-fold and 2-fold increase of laccase activity．Furthermore，PHO5-αpro and FLO10-αpro were constructed by fusing signal peptide of PHO5 and FLO10 with pro-peptide of α-MF respectively．The laccase activity under the leading of FLO10-αpro and PHO5-αpro showed 3-fold and 3. 5- fold laccase activity higher than native signal peptide，and showed 20% and 40% increase compared with saccharomyces cerevisiae α-MF signal respectively．［Conclusion］Signal peptides from high secreted endogenous proteins of P．pastoris X-33 could be effectively used to lead laccase expression in P．pastoris. The activity of POXA1c under the leading of the PHO5-αpro signal peptide was 57.98 U/mL after high density fermentation.

Abstract:Abstract:［Objective］To evaluate the effects of pH on methane production from acetate and the methanogenic community structures.［Methods］ Solutions of phosphate (PB)，2-hydroxyethyl (HEPES)，NaHCO3/CO2 or piperazine-1，4-bisethanesulfonic acid (PIPES) were added into the methanogenic cultures，separately．The substrate consumption was determined by monitoring cumulative methane production，the methanogenic community structuresin the stationary-phase cultures were analyzed using terminal restriction fragment length polymorphism (T-RFLP) of 16S rＲNA gene fragments.［Results］The period of lag phase of methane production in the PB addition culture (ca．40 d) was much longer than that in other pH buffer cultures (20－24 d，P＜0.05)．Approximate 88.3% of acetate was converted into methane in the NaHCO3/CO2 addition culture，while the value decreased to 77%－81% in other pH buffer cultures (P＜0.05)．The maximum specific methane production rate was similar between different pH buffer cultures (P＞0.05)．The relative abundance of members of unclassified bacteria，Spirochaetaceae and uncultured WWE1 increased to (15.5±9.4)%，(7.3±4.6)% and (17.6±6.3)% ，respectively，in the NaHCO3/CO2 addition culture，while synergistaceae decreased to (8.9±8.1)%．In archaeal domain，the acetotrophic methanogen related with Methanosaeta harundinacea became predominant (97±2%) in the PB buffer culture，on the contrary，the concurrence of M．harundinacea，M．concilii and hydrogenotrophic methanogen related with Methanobacteriales were detected in the cultures amended with HEPES，PIPES and NaHCO3/CO2.［Conclusion］ PB retarded the methane production in the acetatemethanogenic culture，NaHCO3/CO2 addition improve methane production from acetate，the pH buffers had not obvious effects on the maximum specific methane production rate of the cultures，the microbial community structures obviously changed along with PB and NaHCO3/CO2 addition. The research would help us to design suitable condition for the growth of methanogenic culture.

Abstract:Abstract:［Objective］Yunnan hot springs have highly diverseammonia-oxidizing archaea (AOA)，which are autotrophic and can fix CO2 using the 3-hydroxypropionate/4-hydroxybutyrate (HP/HD) pathway．In this study，we investigated the abundances of prokaryotic 16S rRNA gene and archaeal accA and amoA genes in the sediments of hot springs of Yunnan Province，and analysed the correlations between the above gene abundances and environmental factors.［Methods］We selectedthe sediments of twenty representative hot springs，anddetected the gene abundances by quantitative polymerase chain reaction (qPCR)．The principal component analysis (PCA) and the Mantel test in the R software package were performed for the correlations of gene abundance and environmental variables.［Results］The bacterial and archaeal 16S rRNA gene abundances were from 6.6×107 to 4.19 × 1011 and from 1.27×106 to 1.51×1011 copies/g sediment，respectively; Archaeal accA and amoA genes were from 8.89×103 to 6.49×105 and from 7.64×103 to 4.36×105 copies/g sediment，respectively. The results of mantel test showed that accA gene was significantly (R=0.98，P＜0.001) correlated with amoA gene; Both of them also were correlated significantly with NO2－and NO3－，but not with pH.［Conclusion］The abundances of bacterial and archaeal 16S rＲNA genes and the ratio between them varied significantly among Yunnan hot springs． The archaealaccA and amoA genes showed significant correlation with each other，validating our previous finding that AOA in terrestrial hot springs might acquire energy from ammonia oxidation coupled with CO2 fixation using the 3-hydroxypropionate/4-hydroxybutyrate pathway.

Abstract:Abstract:［Objective］To explore electricity generation and dynamic characteristics of microbial community of microbial fuel cells (MFC) started-up with mixed sludge of aerobic/anaerobic sludge.［Methods］ single-chamber MFCs were constructed and characteristics of microbial community composition and structure were investigated by culture-independent microbial molecular techniques.［Results］MFC started up successfully after three cycles’operation，and the maximum output voltage was up to 230 mV．The maximum power density reached 11.15 W/m3． at the outer resistance of 1656 Ω．The structure of microbial community on the anodic biofilm was different from that of seed sludge and microbial diversity reduced．The dominant microbial groups on anodic biofilm were Betaproteobacteria (24.90%)，Bacteroidetes(21.30%)，Firmicutes (9.70%)，Gammaproteobacteria (8.50%)，Deltaproteobacteria (7.90%)，Chloroflexi (4.20%) and Alphaproteobacteria (3.60%)．The biofilm-forming microbial genera Zoogloea and Acinetobacter accounted for 5.00% and 3.90% of total community．The abundance of electricity-producing bacteria Geobacter spp．increased from 0. 60% in mixed sludge to 2.60% on the biofilm.［Conclusion］Dominant microbial populations in mixed sludge were selected by long-term acclimation and finally a beneficial microbial group was built on the anodic biofilm．The populations group was helpful to form a functional and active biofilm，which consequently benefited to produce electricity under anaerobic condition by fermenting organic matter．

Abstract:Abstract:［Objective］ We studied the ability of Lactobacillus plantarum ZJ8 to bind fumonisins FB1 and FB2．［Methods］The percentage of FB1 and FB2 bound by the strain was measured by HPLC after bacterial cells and FB1 and FB2 were co-incubated in MＲS media at 37℃ for 4 h.［Results］The percentage of FB1- and FB2 -binding was 89.9% and 95.0%，respectively．The FBs-binding rate of strain ZJ8 reached the maximum at pH 4．Binding of FBs was poor under alkaline conditions and high temperatures．After acid and SDS treatment，the FBs-binding rate significantly increased．The percentage of FB1- and FB2 -binding was 96.8% and 100% for the cell walls of strain ZJ8，respectively．Moreover，about 96.8% FB1 and 100% FB2 was bound to the peptidoglycan of strain ZJ8’s cell walls.［Conclusions］L．plantarum ZJ8 has potential to remove fumonisins．The peptidoglycan of cell walls from strain ZJ8 was proved to be the main site of FBs-binding．

Abstract:Abstract:［Objective］ We aimed to assess the advantage and disadvantage of next-generation pyrosequencing and traditional Denaturing Gradient Gel Electrophoresis (DGGE) in fingerprinting analysis of soil microbial communities．［Methods］We analyzed microbial compositions，abundance and diversity of typical grassland and forest soils by 16S rRNA gene-based pyrosequencing and DGGE to compare the accuracy and reproducibility of the two techniques on soil microbial communities.［Results］ For grassland soils，pyrosequencing technique revealed 22 phyla，54 classes，60 orders，131 families and 350 genera; DGGE only detected 6 phyla，9 classes，8 orders，10 families and 10 genera. The results show that DGGE greatly underestimated soil community compositions．Similar results were obtained for forest soils，and the detection sensitivity of pyrosequencing of forest soils was 3.8，6.7，6.4，19.2 and 39.4 times higher than that of DGGE at the taxonomic levels of phylum， class， order，family and genera respectively． Furthermore， DGGE overwhelmingly overestimated the relative abundance of dominant microorganisms represented by the high-intensity bands，leading up to a 2000-fold difference． Both DGGE and pyrosequencing showed consistent results of microbial diversity changing patterns，although the DGGE-based diversity index was much lower than pyrosequencing.［Conclusion］ Pyrosequencing thus provides more comprehensive and accurate fingerprints of soil microbial community structure than DGGE. DGGE only can represent a few numerically dominant phylotypes with apparent overestimation of their relative abundance in soil microbial communities.

Abstract:Abstract:［Objective］We screened and isolated Ferro-oxidase producing bacteria，for adsorbing iron and manganese．［Methods］The strains producing Ferro-oxidase were isolated from three samples of water．Ferro-oxidase producing strains were screened in shake flask culture，and identified according to morphological features，physiological and biochemical analysis as well as 16S rRNA gene sequence analysis.［Results］We isolated a bacterium S9．The strain was identified as Sphaerotilus natans．This strain had strongest adsorption on iron and manganese among the strains we identified，with 29.02mg/g iron adsorption amount in water，and 66.77% adsorption rate for 4 hours’adsorption．When the adsorption time is 6 h，the adsorption amount of manganese was 34.49mg/g，and the adsorption rate was 70.68%．The optimum temperature and pH value of Ferro-oxidase were 30℃ and 7.5，respectively．Mg2+，Na+，K+ could activate Ferrooxidase，whereas Cu2+ had little impact．While Mn2+，Zn2+ could strongly inhibit Ferro-Oxidase，Pb2+，Ag+ had only modest inhibitory effect.［Conclusion］ Strain S9 had a high Ferro-oxidase activity，and has application potential in sewage treatment.

Abstract:Abstract:［Objective］ To understand the fungal community succession during the phase Ⅱ of Volvariella volvacea compost and clarify the predominant fungi in different fermentation stages，to monitor the dynamic compost at the molecular level accurately and quickly，and reveal the mechanism．［Methods］ The 18S rDNA-denaturing gradient gel electrophoresis (DGGE) and sequencing methods were used to analyze the fungal community structure during the course of compost．［Results］The DGGE profile shows that there were differences in the diversity of fungal community with the fermentation progress．The diversity was higher in the stages of high temperature．And the dynamic changes of predominant community and relative intensity was observed． Among the 20 predominant clone strains，9 were unknown eukaryote and fungi， the others were Eurotiales，Aspergillus sp.，Melanocarpus albomyces，Colletotrichum sp.，Rhizomucor sp.，Verticillium sp.，Penicillium commune，Microascus trigonosporus and Trichosporon lactis．The 14 clone strains were detected in the stages of high and durative temperature.［Conclusion］The fungal community structure and predominant community have taken dynamic succession during the phase Ⅱ of Volvariella volvacea compost.