Abstract:Abstract:Methane is produced exclusively through anaerobic fermentation of both endogenous and exogenous carbohydrates by methanogens．Methane production is detectable in about one third of healthy adult individuals. In recent years，many studies have found that methanogens played an important role in maintaining stability in the gut microbiota Researches have paid much attention on the metabolism of the methane in the gut． The relationship between methane and intestinal dysfunction has also been investigated. The number of methanogens in irritable bowel syndrome patients is different when compared with the normal individuals. Besides，methanogens are potentially linked with obesity. This article reviewes the role of methanogens in gastrointestinal homeostasis and intestinal diseases (irritable bowel syndrome，colon cancer)，as well as the relation between methanogens and obesity.

Abstract:Abstract:Epidemiological studies showed that incidence of colon carcinoma is increased in the world． There are many difficulties to inhibit colon carcinoma because the causes of inducing colon carcinoma were various and interactive each other． Previous evidence supported the balance of the colonic microflora was critical in inhibiting colon carcinoma and the protection by colonic microflora could be improved by ingesting lactobacilli． Therefore，the biological functions and anticancer effects of lactobacilli attract attention of researchers． In this review we discussed the causes of colon carcinoma; the anticancer mechanisms of lactobacilli on the basis of our own studies． Eventually，we summarized the effects of anticancer of different components and metabolic products extracted from lactobacilli．

Abstract:Abstract:Bacterial wilt caused by Ralstonia solanacearum is one of the most devastating plant diseases worldwide．The syringe-like type III secretion system (T3SS) plays a crucial role in its pathogenicity．R.solanacearum uses the T3SS to inject effector proteins (Type III effectors) into the cytoplasm of host cells，causing diseases in susceptible plants or triggering the hypersensitive response in resistant plants． In this article we review recent advances in studies of R．solanacearum T3SS and highlight their unique features.

Abstract:Abstract:［Objective］The aim of this study was to analyze the diversities and differences of several mammalian’s faecal bacteria，to understand the relationships between bacterium diversities and animals‘ evolutionary and animals’feeds.［Methods］ Genomic DNA of feces was extracted and amplified for the 16S rDNA V3 tags，and then the tags were sequenced by 454 sequencing．QIIME were used to analyze faecal bacterial diversities.［Results］Faecal bacteria of all animals were dominated by Firmicutes，Bacteroidetes and Proteobacteria． Bacterial diversities of Hylobates hoolock，Pan troglodytes and Rhinopithecus roxellanae were the highest，followed by Panthera tigris altaica，Ailuropoda melanoleuca and Ursus thibetanus were the lowest through α diversity analysis．The constituents of faecal bacteria among Hylobates hoolock，Pan troglodytes and Ｒhinopithecus roxellanae were similar．The constituents of faecal bacteria among Ailuropoda melanoleuca，Ursus thibetanu，and Panthera tigris altaica were similar． Mainly for containning Fusobacteria，the faecal bacterial of Panthera tigris altaica differed from the other two carnivore animals through β diversity analysis.［Conclusion］ The dominating faecal bacteria were obvious，the bacteria similarities of the two repetitions were the highest． The diversities of each animal were different and higher in the primates． Both evolution and food were related to faecal bacteria． This study provided some references for exploring the new microorganism and further research of faecal bacteria．

Abstract:Abstract:［Objective］We used Inter-Simple Sequence Repeats (ISSR) markers to reveal the genetic diversity of 95 Fusarium oxysporum f．sp．cubense (FOC) isolates from banana in China，for the rational control of the disease．［Methods］ Eight primers were chosen for analyzing FOC isolates to study their genetic diversity by ISSR-PCR． All isolates were clustered using Unweighted Pair-Group Method with Arithmetic means ( UPGMA) analysis by NTSYSpc v2.10e software.［Results］A total of 52 sites were generated，among them 92. 3% were polymorphic．Genetic distance was 0.57 to 1.00 based on the Nei’s standard． Isolates were grouped into six distinct clusters (A，B，C，D，E and F)based on ISSR analysis using a genetic distance threshold of 0.68，the proportion of 51.06%，39.58%，5.20%，2.08%，1.04%，and 1.04%，respectively.［Conclusion］There were high levels of genetic variation among the FOC isolates，and the ISSR clustering groups had obvious correlation with hosts and races of the pathogen.

Abstract:Abstract:［Objective］The longer the Pericarpium Citri Reticulatae is preserved，the better medicinal values will be．The present work aims to isolate beneficial microbes isolated from the 7-year orange peel that might be used to produce high quality Pericarpium Citri Reticulatae． ［Methods］The microbes isolated from the 7-year orange peel using 4 mediums were grouped by SDS-PAGE patterns of the whole-cell protein electrophoresis and IS-PCR DNA fingerprinting． The representative strains were further studied by physiological and biochemical tests，and phylogeny analysis． ［Ｒesults］Total 23 bacteria were obtained from the 7-year orange peel．These strains were classified into 4 groups: the strains of group I belonged to Bacillus; the strains of group II，group III and group IV were closed to Paenibacillus.［Conclusion］Among the representative strains of group I，II，III and IV，only the representative strain cp20 of group II has the ability of strong utilizing citrate obviously． The strain cp20 of group II were further applied to making Pericarpium Citri Reticulatae.

Abstract:Abstract:［Objective］ We expressed a nikkomycin biosynthetic gene cluster in the well-characterized surrogate Streptomyces coelicolor M1146． ［Methods］By using PCR-targeting method，we replaced the promoters of sanG and sanF in pNIK，which contains nikkomycin biosynthetic gene cluster，with the hrdB promoter to generate pNIKm．We transferred pNIK and pNIKm into S．coelicolor M1146 by intergeneric conjugation and obtained M1146-NIK and M1146-NIKm，respectively． We then evaluated expression of the gene cluster in the heterologous host by RT-PCR． Furthermore，we also compared the antifugal activity and nikkomycin production of M1146-NIK and M1146-NIKm by bioassay against Alternaria longipes and HPLC analysis.［Results］ M1146-NIK and M1146-NIKm exhibited antifungal activity，and they can produce a trace amount of nikkomycin X，nikkomycin Z and pseudo-Z． There was a substantial accumulation of uridine in M1146-NIK，whereas substantial accumulations of uridine，ribofuranosyl-4-formyl-4-imidazolone and pyridylhomothreonine were observed in M1146-NIKm．［Conclusion］We successfully expressed the nikkomycin biosynthetic gene cluster in the heterologous host and identified nikkomycins and some of its key biosynthetic intermediates． This study will provide the basis for enzymatic reaction of the condensation between the two nikkomycin moieties and for the generation of hybrid antibiotics by combinatorial biosynthesis.

Abstract:Abstract:［Objective］ Anoxybacillus flavithermus subsp．yunnanensis is now the only species of thermophilic bacteria able to tolerate toxic solvents at high temperature．The adaptive responses of A．flavithermus subsp． yunnanensis E13T to toluene on the level of fatty acid composition of membrane were studied in detail．［Methods］The extraction of fatty acids was performed according to the method described in the Sherlock Microbial Identification System manual．The fatty acid compositions were analyzed by gas chromatography mass spectrometry (GC-MS)．［Results］In presence of 0.3% (V/V) toluene，key moment to adapt the saturated straight-chain fatty acids was that when cells grew from the lag phase to the initial growth phase in liquid． The saturated straight-chain fatty acids were continuously decreased as the strain E13T to grow．In survival of the cells in 100% toluene，the saturated straight-chain fatty acids increased significantly.［Conclusion］A．flavithermus ssp． yunnanesis E13T alters its membrane fluidity via fatty acid composition to become more rigid when it is exposed to solvent，which is consistent that commonly found in mesophilic organic solvent-tolerant bacteria． However，it adapted its membrane by increasing straight-chain saturated fatty acids，rather than unsaturated fatty acids，which was demonstrated in mesophilic organic solvent-tolerant bacteria．

Abstract:Abstract:［Objective］ To assess the effect of cellular activity on ε-poly-l-lysine (ε-PL) biosynthesis and thereby to rationally improve the production，we studied the cellular activity，ε-PL formation and other parameters cross flask fermentation by Streptomyces ahygroscopicus． ［Methods］Laser scanning confocal microscopy and a colorimetric method were used to determine cellular activity using BacLight Live /Dead and 5-cyano-2，3-ditolyl tetrazolium chloride (CTC) as viable stains． To enhance the activity of the cells in the ε-PL production period，yeast extract was added．［Results］During ε-PL submerged fermentation in flasks，most cells were active in the growth period (0－16 h); cells had metabolic activity in the growth and earlier ε-PL production periods between 0 and 30 h fermentation．Almost no activity was detected after 48 h fermentation when no ε-PL was produced． The improved fermentation achieved 2.24 g/L ε-PL from 1.04 g/L．［Conclusion］Biosynthesis of ε-PL can be boosted by up-regulating cell activity in its production phase.

Abstract:Abstract:［Objective］We studied the regulation effect of glycometabolic protein，catabolite control protein A (CcpA)，on the biosynthesis of capsular polysaccharide (CPS) in Streptococcus pneumonia．［Methods］His-tagged CcpA protein was expressed in E．coli BL21(DE3) and purified by Ni2 + affinity chromatography．The anti-CcpA serum was obtained from immunized mice and the antibody titer was determined by ELISA．The conservation of CcpA was determined by Western blotting． In addition，binding of CcpA protein to the promoter region of cps locus was verified by EMSA． The amount of capsular polysaccharide was determined by ELISA and compared among wild type D39 strain，ccpA mutant and the complement strains．［Results］CcpA protein was conserved in different pneuococcal serotypes included in this study．EMSA assay revealed that CcpA protein could bind the promoter region of the cps locus in a dose-dependent manner．The absence of ccpA gene led to an increased expression of capsular polysaccharide，and complement expression of CcpA protein significantly reduced the amount of capsular polysaccharide．［Conclusion］ CcpA is conserved in Streptococcus pneumonia，which plays a role in regulation of the expression of the capsular polysaccharide.

Abstract:Abstract:［Objective］This study was aimed to obtain a quorum quenching N-acylhomoserine lactonase gene from Bacillus subtilis SS6 and to characterize the enzyme.［Methods］We amplified N-acylhomoserine lactonase gene from B．subtilis SS6 by PCＲ methods. Gene aiiASS6 was cloned into the expression vector of pET28(a) and transformed into Escherichia coli BL21. The activity of AiiASS6 on signal N-(3-Oxooctanoyl)-L-homoserine lactone was characterized by high performance liquid chromatography (HPLC).［Results］We successfully cloned an N-acylhomoserine lactonase gene from B．subtilis SS6 strain，namely aiiASS6 (GenBank: KP125494)．The sequencing result showed that the length of aiiASS6 was 891 bp and the gene contained an Open Ｒeading Frame encoding 297 amino acids． HPLC results showed that AiiASS6 was very active between 50 and 90℃ and the optimal pH was 7.6．Lineweaver-Burk treatment of the data yielded apparent Km and the Vmax was 0.998 mmol/L and 22.3 U/mg，respectively． Moreover，the relative activity of the enzyme remained 86% after storing at 4℃ for 3 months.［Conclusion］Our findings will be helpful for further studies.

Abstract:Abstract:［Objective］We improved the thermostability of LipA from Burkholderia cecapia ZYB002 by protein engineering technology to expand the application of lipase LipA.［Method］On the basis of B-factor value of lipase LipA，series of potential mutation hotspots were selected for iterative saturation mutagenesis and the corresponding small mutation gene libraries were then constructed to screen the hyperthermal variants.［Results］ From the above mutation libraries，we obtained a series of mutants whose enzyme half-life at 55℃ increased by 1.7 to 2.2-fold． ［Conclusion］B-factor iterative test (B-FIT) is feasible to mutate thermostable strains．

Abstract:Abstract:［Objective］Oil pollution poses a severe threat to ecosystems，and bioremediation is considered as a safe and efficient alternative to physicochemical.［methods］ for eliminating this contaminant．In this study，a gram-negative bacteria strain SJTD-2 isolated from oil-contaminated soil was found capable of utilizing n-alkanes and crude oil as sole energy sources．The efficiency of this strain in degrading these pollutants was analyzed.［Methods］Strain SJTD-2 was identified on the basis of its phenotype，its physiological features，and a comparative genetic analysis using 16S rRNA sequence． Growth of strain SJTD-2 with different carbon sources (n-alkanes of different lengths and crude oil) was assessed，and the gas chromatography-mass spectrometry method was used to analyze the degradation efficiency of strain SJTD-2 for n-alkanes and petroleum by detecting the residual n-alkane concentrations.［Results］ Strain SJTD-2 was identified as Pseudomonas aeruginosa based on the phenotype，physiological features，and 16S rRNA sequence analysis．This strain can efficiently decompose medium-chain and long-chain n-alkanes (C10 -C26)，and petroleum as its sole carbon sources．It preferred the long-chain n-alkanes (C18 -C22)，and n-docosane was considered as the best carbon source for its growth．In 48 h，500 mg /L n-docosane could be degraded completely，and 2 g/L n-docosane was decomposed to undetectable levels within 72 h．Moreover，strain SJTD-2 could utilize about 88% of 2 g/L crude oil in 7days．Compared with other alkane-utilizing strains，strain SJTD-2 showed outstanding degradation efficiency for long-chain n-alkanes and high tolerance to petroleum at elevated concentrations．［Conclusion］The isolation and characterization of strain SJTD-2 would help researchers study the mechanisms underlying the biodegradation of n-alkanes，and this strain could be used as a potential strain for environmental governance and soil bioremediation．

Abstract:Abstract:［Objective］We analyzed endophytic fungi from 4 bryophyte species: Mnium sp., Marchantia polymorpha，Polytrichum commune and Hylocomium splendens，collected from Dawei Mountain，Southwest of China，to study the diversity of fungal endophytes of bryophytes in different environment and their roles in the evolution from aquaqtic plant to terrestrial plant.［Methods］Endophytic fungi were isolated by culturable method and identified to species or genera level based on morphological characteristics and molecular analysis.［Results］Nine hundred fungal endophytes were isolated from 630 tissue segments of 4 different plants．All endophytes were identified to 57 taxon．Among them，Xylaria， Colletotrichum，Penicillium and Trichoderma were the dominant genera． The Shannon index (H') and similarity coefficients (CS) of endophytic fungi from 4 plants were 1.80－3.22 and 0.409－0.613，respectively，higher than those of bryophytes growing in extreme environments． ［Conclusion］The diversity and richness of endophytes from 4 bryophytes in Dawei Mountain are similar to those of plants growing in the similar environment.

Abstract:Abstract:［Objective］To develop a rapid technique for estimating the percentage of bradyrhizobial nodule occupancy，we comparaed the differences of genetic diversity of peanut bradyrhizobia with culture-independent and culture-dependent methods．［Methods］ We used the traditional media plate technique for isolation of peanut bradyrhizobia and directly collected the bacteroids from peanut nodules． The BOX-PCＲ fingerprintings were compared after amplification with the DNAs of peanut bradyrhizobial isolates by culture-dependent approach and bacteroids by culture-independent approach．［Results］The percentage of testing for peanut bacteroids was 81. 8% with culture-independent method，and 85 genotypes of BOX-PCR were obtained． The percentage of isolation for peanut bradyrhizobia strains was 72. 7% and 71 genotypes of BOX-PCR were produced． There were totally 17 corresponding BOX-PCＲ genotypes obtained by both methods．［Conclusion］The culture independent method for direct analysis of genetic diversity from bacteroids in nodules can much more rapidly and clearly find the dominant genetic groups in different soil samples and fast figure out the percent of the rhizobia nodule occupancy．

Abstract:Abstract: ［Objective］ To determine if the point mutation of nt313713 T → C in the promoter region of capsular polysaccharide biosynthesis (cps) operon is responsible for the deficiency of capsular polysaccharide in S．pneumoniae SPY1 strain.［Methods］Western blot was used to compare the amounts of capsular polysaccharide between the wild-type strain and SPY1 strain． Ｒeal-time quantitative PCR was used to determine transcription levels of the first four genes of cps operon，cps2A，cps2B，cps2C and cps2D． The lacZ gene was used as a reporter gene to report the strength of the promoters on cps transcription．The cps promoter was amplified by PCＲ from the wild-type strain or SPY1 strain．The amplified fragments were cloned into shuttle vector pEVP3，transformed into S．pneumoniae D39 or SPY1 strain．The transcription activities of the promoters on capsular polysaccharide biosynthesis were determined by using β-galactosidase as the reporter．Transmission electron microscopy and the Neufeld test were used to reveal the changes in capsule．［Results］Compared to that in the wild-type strain，mＲNA levels of the cps genes were significantly decreased in SPY1 strain．The amount of CPS was also decreased in SPY1 strain． β-galactosidase activities in SPY1-pEVP3-cps promoterSPY1 and D39-pEVP3-cps promoterSPY1 were decreased by about 79% and 76%，respectively，compared to that of the control． Transmission electron microscopy showed that the amount of the capsular polysaccharide of SPY1-pEVP3-cps promoterD39 strain was restored to the wild-type level. In addition，capsular polysaccharide was absent in the D39-pEVP3-cps promoterSPY1 (NC_008533.1 313713 T→C) strain as determined by Neufeld test.［Conclusion］The point mutation of nt313713 T→C in the cps promoter region results in a significantly reduced transcription of the cps genes，which is responsible for the significant reduction or even absence of the biosynthesis of capsular polysaccharide in SPY1 strain.

Abstract:Abstract:［Objective］Phosphorous (P) is one of the essential elements for tree growth in forests．It is beneficial to characterize oxalate secretion by ectomycorrhizal fungi in response to P supply for understanding the mechanism of P mobilization in soils.［Method］In the present experiment，the influence of P supplies and inhibitors of Ca2 + signal/anion channel on oxalate efflux in ectomycorrhizal fungi was studied in the pure liquid culture with various P concentrations.［Results］ Ectomycorrhizal fungi released a large amount of H + and organic acids such as oxalate，acetate，malate，citrate and succinate，which are important for mobilization of insoluble P in the soils. Oxalate accounted for 15. 14% to 36. 01% of the total organic acids released by the fungi and was accelerated in culture solution under the condition of low P supply，but inhibited under normal and high P.［Conclusion］Ectomycorrhizal fungi released a large amount of H + and organic acids，particularly oxalate，which might be beneficial to inorganic P mobilization in the soils and improvement of P nutrition for their host plants.