Abstract:Abstract:3-phenoxybenzoic acid (3-PBA) with estrogen toxicity is one of the intermediate products of most pyrethroid pesticides．3-PBA is difficult to degrade in the natural environment，and threatens food safety and human health．Microbial degradation of pyrethroids and their intermediate product (3-PBA) has become a hot topic in recent years．Here，we reviewed microbial species，degrading enzymes and degradation genes，degradation pathways of 3-PBA degrading and the application of 3-PBA degradation strains．This article provides references for the study of 3-PBA degradation by microorganisms．

Abstract:Abstract:We reviewed the history and applications of microorganism co-cultivation in food，agriculture，industry and sewage purification，and summarized ecology relationships between co-culture microorganisms． Joint mixed culture，sequence mixed culture and immobilized cells mixed culture have been used widely and lots of achievements have been made，for example，obtaining metabolites that are difficult to achieve or too low production in pure culture，transforming traditional fermentation industry，producing energy substance，improving substrate utilization ratio，expanding the scope of substrates and degrading toxic substances． Ｒesearch reports indicate there are many ecology relationships between microorganisms，such as collaborative metabolism，induction effect，quorum sensing and gene transfer． The ecological interplay mechanism of co-culture microorganisms should have a further research，which will lay the foundation for developing applications of microorganism co-culture．

Abstract:Abstract:As the most abundance biological agents in the oceans，viruses can influence the physiological and ecological characteristics of host cells through viral infections and lysis，and affect the nutrient and energy cycles of the marine food chain． Thus，they are the major players in the ocean biogeochemical processes． The problems caused by global climate changes，such as sea-surface warming，acidification，nutrients availability，and deoxygenation，have the potential effects on marine viruses and subsequently their ecological and biogeochemical function in the ocean． Here，we reviewed the potential impacts of global climate change on the ecological characteristics (e. g．abundance，distribution，life cycle and the host-virus interactions) and biogeochemical significance (e．g．carbon cycling) of marine viruses．We proposed that marine viruses should not be ignored in the global climate change study.

Abstract:Abstract:［Objective］To study the genetic diversity and phylogeny of Rhizobia isolated from Sesbania cannabina growing on the tidal flat in Rudong County and screen high-efficient growth-promoting strains as Ｒhizobia inoculator to S．cannabina．［Methods］Phylogenetic analyses were based on 16S rRNA gene，housekeeping genes (recA，atpD，glnII) and symbiotic genes (nodA，nifH)．The growth-promoting efficiency was tested by plant inoculation assay on S．cannabina in greenhouse．［Results］ The 32 isolates belonged to Ensifer，Neorhizobium，Rhizobium，and most closely related to E．meliloti，N． huautlense，R．pusense．The phylogenies of nodA and nifH were congruent，and most closely related to E. saheli． The 7 representative isolates were resistant to high concentration of NaCl (5%，W/V)，and YIC5082 grew well in TY medium with 6% NaCl．In plant inoculation assay，all the 7 representative isolates were effective on symbiotic nitrogen fixation，and 6 out of the 7 isolates significantly enhanced the fresh weight and height of plants．［Conclusion］Ｒhizobia isolated from S．cannabina growing on the tidal flat in Ｒudong County showed rich genetic diversity． N．huautlense and E． meliloti were the dominant species．Most of the isolates showed fine growth-promoting efficiency and salt tolerance．YIC5077 showed the best growth-promoting efficiency，good nodulation and nitrogen fixation abilities，which has promising potential applications as Ｒhizobia inoculator to S. cannabina．

Abstract:Abstract:［Objective］To isolate thermophilic bacteria to degrade organic substances of dead-pig.［Methods］Primary screening was done by using diluted plate count and selective medium，and then enzyme activity was measured for secondary screening． Two thermophilic bacterial strains N-3 and Y-3 were isolated，and could degrade protein and lipids．To test their effect，the isolates were mixed (V:V = 1:1，the number of bacteria was 108 CFU /mL) and inoculated in dead-pigs and sawdust composting with different doses (0%，0.3%，0.6% and 0.9% of the wet weight of fermentation materials).［Results］Strain N-3 was identified as Bacillus aestuarii and Y-3 as Geobacillus thermodenitrificans，based on their 16S rDNA gene sequences． The composting temperature of the 0.3%，0.6% and 0.9% inoculation group could reach 60 ℃ and maintain at the high temperature for about 10 d，which is higher than control (P＜0.01)．At the end of composting，the dead-pig degradation rate of the (0%，0. 3%，0.6% and 0.9% inoculation groups were 71.2%，75.7%，96.7% and 97.1%，respectively．The groups of 0. 6% and 0.9% were significantly higher than the control (P＜0.01)．［Conclusion］ Sufficient amount inoculation of thermophilic bacteria (＞0.6%) could effectively increase composting temperature，maintain thermophilic stage for longer time，and accelerate degradation of dead-pig by composting．

Abstract:Abstract:［Objective］ To screen and identify a bacterium capable of converting agar to neoagaro oligosaccharides．［Methods］We took samples of porphyra haitanensis and nearby seawater，and then used the medium containing 1‰ agar to enrich the target bacteria． The target isolates were obtained by dilution-plate method，of which crude enzymes were further obtained by liquid culture． We adopted DNS method to determine the target bacteria which can convert agar to neoagaro oligosaccharides． The phylogenetics was identified by analyzing 16S rDNA sequence and combining the strain’smorphological and bacterial colonial physiological biochemical characteristics．［Results］ We isolated a gram-negative bacterial strain HJPHYXJ-1 capable of transforming agar to neoagaro oligosaccharides． Basic Local Alignment Search Tool (BLAST) search of HJPHYXJ-1's 16S rDNA sequence on GenBank suggested that the similarity between this strain and Vibrio natriegens reached 99%．In addition， the morphological and physiological biochemical characteristics of HJPHYXJ-1 also showed highly similarity to Vibrio natriegens．So we identified HJPHYXJ-1 as Vibrio natriegens．The results of HPLC suggested that the metabolite of enzymatic degradation was neoagaro oligosaccharides． ［Conclusions］HJPHYXJ-1 or the new isolate of Vibrio natriegens was capable of converting agar to neoagaro oligosaccharides．

Abstract:Abstract:［Objective］We isolated 339 bacillus strains from 72 soil samples all over the country，then purified their antimicrobial compounds and studied the antibacterial activity，to enrich bacillus resources and explore their second metabolites.［Methods］A bacillus strain with strong antibacterial activity was selected by dilution plate and water bath heating from a soil sample from a peanut plantation in Henan Province; this strain was identified according to morphological observation，physiological and biochemical characteristics，and consequences of 16S rRNA homologous analysis． Antibacterial compound from the identified strain，Bacillus amyloliquefaciens X030，was separated and purified by acetone precipitation，Sephadex chromatography，C18 reverse phase column chromatography．Its molecular weight was analyzed by LC-MS/MS． The antibacterial activity was characterized by disc diffusion and plate two-way cultivation．［Results］Bacillus amyloliquefaciens was isolated that not only has antibacterial activity against Staphylococcus aureus，Candida albican and Saccharomycetes; but also against Pyriculariaoryzae，Chili pointed cell anthrax，Gloeosporium eriobotryae speg and Phytophthora parasitica．The compound was confirmed as polypeptide．［Conclusion］ Bacillus amyloliquefaciens X030 can produce a polypeptide that inhibits pathogenic bacteria and plant pathogenic fungi．

Abstract:Abstract:［Objective］We analyzed the transcriptional regulation of aco gene cluster and the phenotype of acoR mutant，to determine the effect of acoR deletion on sporulation efficiency and Cry protein production． ［Methods］Sequence of aco gene cluster in Bacillus thuringiensis was analyzed by sequence alignment．RT-PCR was carried out to reveal the transcriptional units of the aco gene cluster．acoR insertion mutant was constructed by homologous recombination．Transcriptional activity was analyzed by promoter fusions with lacZ gene．Comparison of the Cry1Ac protein production was determined by protein quantitation．［Results］The aco gene cluster was composed of four genes．The acoABCL formed one transcriptional unit．The transcriptional activity of acoA promoter sharply decreased in sigL and acoR mutants，respectively． Deletion of acoR had no effect on growth and Cry protein production，but decreased the motility of cells and sporulation efficiency．［Conclusion］The acoR gene cluster is controlled by Sigma 54 and activated by AcoR． Deletion of acoR has no effect on Cry protein production，but decreased the motility of the cells.

Abstract:Abstract:［Objective］To research the pathogenicity of Salmonella Pathogenicity Island 2 (SPI-2) deletion mutant of Salmonella Pullorum and preliminary explore the feasibility of developing safe attenuated Salmonella Pullorum candidate vaccine strain.［Methods］TheSPI-2 (－40 kb) deletion mutant of Salmonella Pullorum S06004 was constructed using the λ-red recombinant system． Then the biological characteristics such as growth rate，biochemical properties，genetic stability and virulence were evaluated between the deletion mutant strain S06004ΔSPI2 and its parent strain S06004．［Results］S06004ΔSPI2 was successfully constructed． The growth rate and biochemical properties of S06004ΔSPI2 were consistent with those of its parent strain S06004．The mutant was stable with the deletion of SPI-2．Chicken lethal test showed that the LD50 of S06004ΔSPI2 was 252 times higher than the parent strain S06004．［Conclusion］The virulence of S06004ΔSPI2 was obviously attenuated．This study provided basic data for further study of the functions of SPI-2，and implied its potential to develop attenuated Salmonella vaccine.

Abstract:Abstract:［Objective］The aim of this study was to identify the microbiological characteristics of a Lysinibacillus strain isolated from storage liquid in the stems of Populus euphratica trees． ［Methods］ Bacterial morphology and cultivation characteristics were studied by conventional cultivation and dyeing method． Biochemical characteristics，fatty acid components，menaquinone，polar lipids，phylogenetic analyses of 16S rＲNA，determination of (G+C) mol% content and DNA- DNA hybridization were studied by polyphasic taxonomic approach．［Results］Strain ML-64 is Gram-positive，endospore-forming and rod-shaped． Colonies are pale-yellow，circular and entire margin．Temperature range for growth is between 10 and 45 ℃ (optimum at 37 ℃)．The pH range for growth is between 6. 0 and 9.0 (optimum at 7.0)．NaCl concentration range for growth is between 0 and 6% (optimum 3%)．Cells were positive for lipid esterase，Arginine dihydrolase，urease and Voges-Proskauer test． No sugars were fermented in the API 50CH strips．L-Serine，Methyl Pyruvate，α-Keto-Butyric，Acetoacetic Acid were oxidized．Resistant to polymyxin b (30 μg)，novobiocin (30 μg)，peillin G (10 U)．16S rRNA gene sequence demonstrated that strain ML-64 was closely related to Lysinibacillus chungkukjangi 2RL3-2T (100%)，Lysinibacillus sinduriensis BLB-1T (99.1%)．DNA-DNA relatedness were 82% and 50.9% with Lysinibacillus chungkukjangi 2RL3-2T and Lysinibacillus massiliensis CIP108446T，respectively． The genomic DNA G+C content of strain ML-64 was 36.8% (mol)． Major fatty acids were iso-C15:0 ( 55.05% ) and anteiso-C15:0 (20.70%)．The predominant menaquinone is MK-7．Based on the phenotypic phylogenetic and genotypic analyses，the strain ML-64 is concluded to represent a new mutant strain of the Lysinibacillus chungkukjangi species，GenBank accession number is KC609752．［Conclusion］As an endophytic bacterium of Populus euphratica，genomic structure of the strain ML-64 was greatly differentiated from the closest strain L． chungkukjangi，and suitably adapted to the endophytic environment of Populus euphratica．

Abstract:Abstract:［Objective］ We constructed highly efficient expression systems for agarase AgaD and optimized its culture conditions．［Methods］First，the codon usage of AgaD was optimized to make it suitable for expression in E.coli． Then，the gene expression vector was transformed into different E．coli hosts． According to the“N-end rule”that is related to the in vivo half-life of a protein，a mutant was constructed． Finally，the effects of CaCl2 and glycine on enzyme production were evaluated．［Results］A highly efficient expression system of agarase AgaD was constructed，named pET-22b(+)-optagaDx-AD494 (DE3)．Replacing N-terminal second amino acid phenylalanine with alanine significantly improved agarase production and shortened the fermentation period．The extracellular enzyme activity was further up-regulated by CaCl2 and glycine． After optimization，the extracellular enzyme production raised from 20 U/L to 11300 U/L，more than 500 folds.［Conclusion］The high expression system of AgaD provides good basis for further studying agarases.

Abstract:Abstract:［Objective］To reveal the relationship between bacterial community and the environmental in Zuohai lake，Fuzhou City．［Methods］The abundance of total bacteria was studied using DAPI staining; the composition，distribution and the dynamics of bacterial community were examined using both the denaturing gradient gel electrophoresis (DGGE) and the 16S rRNA gene clone library analyses over a 2-year periods from October 2011 to August 2013． Moreover，multivariate statistical analysis was used to analyze the relationship between bacterial community and environmental factors．［Results］The total numbers of bacteria ranging from 4.91×106 cells/mL to 18.71×106 cells/mL，and the seasonal variation of bacterial abundance was obviously stronger than the spatial heterogeneity． DGGE and clone library analysis revealed that bacterial communities were mainly affected by temporal changes． Phylogenetic analysis showed that bacteria belonging to 11 phyla were identified． Members of β-Proteobacteria and Cyanobacteria group were the predominated lineage，followed by α-Proteobacteria，Actinobacteria and Bacteroidetes． Redundancy analysis (RDA)suggested that water temperature，pH，total nitrogen，total phosphorus and chlorophyll a content contributed significantly to the bacteria-environment relationship．［Conclusion］There is rich bacterial diversity in Zuohai lake，the patterns of change in bacterial communities showed that the seasonal difference might have a significant impact on structuring the bacterial communities in the lake.

Abstract:Abstract:［Objective］ In order to study the community diversity of rhizosphere soil ammonia-oxidizing bacteria，Halocnemum strobilaceum，Ｒeed and Salicornia in Ebinur Lake Wetland were investigated．［Methods］The clone libraries of amoA gene were constructed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP)，and phylogenetics were analyzed．To explore the community structure of rhizosphere amomonia-oxidizing bacteria，we combined rhizosphere physicochemical factors of the three plants．［Results］ Phylogenetic analysis of the amoA gene fragments showed that all of AOB sequences from shrimp of three plants rhizosphere were affiliated with Nitrosomonas or Nitrosomonas-like phyla，Nitrosospira phyla was not discovered． Three plants rhizosphere composition includes 9 OTUs，12 OTUs and 7 OTUs respectively． Coverages of all libraries of the three plants rhizosphere were over 99% and strongly representative． The richness index，chao1 index，ACE index and Shannon index of the three libraries were as follows，Reed rhizosphere AOB was much higher than Halocnemum strobilaceum rhizosphere AOB，and Salicornia rhizosphere AOB was the lowest．［Conclusion］ This study provides a basis for understanding the community diversity and structure of rhizosphere soil ammonia-oxidizing bacteria in Ebinur Lake wetland.

Abstract:Abstract:［Objective］ Purpose of this work was to explore the distribution of LuxS/AI-2 quorum sensing system in Edwardsiella，and analyze expression characteristics and biological function of the key gene luxS accompanying the growth of Edwardsiella.［Methods］ The full-length of AI-2/LuxS of Edwardsiella tarda was cloned by PCR based on the sequence on NCBI，then characteristics and conservative structure of this protein-coding gene were analyzed using web database and bioinformatics tools．The anti-rabbits serum was prepared after this protein was purified through prokaryotic expression． The expression level of luxS gene was analyzed during different growth stages using Western blot and further the distribution of luxS gene in Edwardsiella tarda was studied by this technique． To explore whether the specific LuxS is AI-2 dependent we used the method of antibody neutralization to analyze the effect of the anti-rabbits serum on the growth of Edwardsiella tarda． ［Results］The luxS gene was obtained by PCR，its length was 516 bp，and the sequence was highly conserved in Edwardsiella tarda．Results of Western blot analysis showed that LuxS expression level was the lowest in the lag phase and began increasing when entered index phase．It reached the peak in the late index phase and decreased in decline phase． Moreover，Antibody neutralization results showed that，it can elongate the growth plateau phase，but it has no significant effect on bacterial growth．［Conclusion］The key gene of luxS was highly conserved，and LuxS/AI-2 was widely distributed among Edwardsiella tarda．The expression level of luxS gene was different during every growth period，expression of LuxS protein reached the highest level in the late index phase.

Abstract:Abstract:［Objective］ To determined the role of vacuolating autotransporter toxin (vat) gene in avian pathogenic Escherichia coli (APEC)，we detected the biological characteristics and pathogenicity of vat gene mutant strain of APECO1．［Methods］We constructed the vat mutant and complementary strain of APEC-O1 by the Red recombination system and plasmid pSTV28． Then we compared the growth curve，motility，agglutination，biofilm formation and pathogenicity of mutant strain，wild-type strain and complementary strain．［Results］ The vat mutant did not affect the growth and resistance to environment stress of APEC．However，inactivation of APEC-O1 vat gene resulted in enhanced motility， diminished agglutination，decreased biofilm formation and attenuated virulence in ducks．［Conclusion］ These data indicated that Vat affect the motility，agglutination，biofilm formation and virulence of APEC-O1，which help us to understand the role of the Vat in the APEC pathogenicity．

Abstract:Abstract:［Objective］ To understand the epidemic tendency and antibiotics-resistance among Shigella sonnei isolates collected from different regions by antibiotic susceptibility testing，PCＲ amplification of the resistance genes and genotyping．［Methods］ The susceptibilities to 21 antibiotics of 54 S． sonnei strains were determined by broth microdilution using a 96-well microtiter plate．The amplification of resistance genes was performed by PCR．Pulsed field gel electrophoresis genotyping method was applied to analyze their genetic relationships，and BioNumerics software was used to analyze the PFGE patterns． ［Ｒesults］ All tested S． sonnei strains were resistant to Trimethoprim/Sulfamethoxazole，Tetracycline，Ticarcillin，Ampicillin and Gentamicin，whereas sensitive to Imipenem，Cefepime，Levofloxacin，Norfloxacin and Amikacin．A total of 7 different antibiotic resistance genes including blaTEM，blaCTX and intI were identified in the multidrug-resistant S．sonneis strains．PFGE patterns of all the isolates showed a high genetic homology．［Conclusion］It is of great importance to strengthen the surveillance of S．sonnei from different regions in order to reduce the prevalence of multidrug-resistant strains.