Abstract:Abstract:Bocavirus was considered as a member of the subfamily parvoviriae of the family parvoviridae，which includes bovine bocavirus，minute virus of canines，human bocavirus，as well as the newly identified swine bocavirus，gorilla bocavirus，feline bocavirus，canine bocavirus and bocavirus identified in California sea lion sample． At present，as an emerging pathogen，bocavirus members attract great attention by researchers worldwide． We reviewed published papers in combination with our study for several aspects of bocavirus family including their classification，genome structure and replication，clinical pathogenic characteristics and molecular pathogenesis.

Abstract:Abstract:［Objective］This study aimed to detect and quantify Cronobacter in 300 powdered milk samples and 50 nonpowdered milk samples． Totally，24 Cronobacter (formerly Enterobacter sakazakii) strains isolated from powdered milk and other foods were identified and confirmed．［Methods］Cronobacter strains were detected quantitatively using most probable number (MPN) method and molecular detection method． We identified 24 Cronobacter strains using biochemical patterns，including indole production and dulcitol，malonate，melezitose，turanose，and myo-Inositol utilization． Of the 24 strains，their 16S rRNA genes were sequenced，and constructed phylogenetic tree by N-J (Neighbour-Joining) with the 16S rRNA gene sequences of 17 identified Cronobacter strains and 10 non-Cronobacter strains．［Results］ Quantitative detection showed that Cronobacter strains were detected in 23 out of 350 samples yielding 6. 6% detection rate． Twenty-four Cronobacter strains were isolated from 23 samples and the Cronobacter was more than 100 MPN/100g in 4 samples out of 23 samples． The 24 Cronobacter spp． isolates strains were identified and confirmed，including 19 Cronobacter sakazakii strains，2 C． malonaticus strains，2C． dubliensis subsp． lactaridi strains，and 1 C． muytjensii strain．［Conclusion］The combination of molecular detection method and most probable number (MPN) method could be suitable for the detection of Cronobacter in powdered milk，with low rate of contamination and high demand of quantitative detection．24 isolated strains were confirmed and identified by biochemical patterns and molecular technology，and C．sakazakii could be the dominant species．The problem of Cronobacter in powdered milk should be a hidden danger to nurseling，and should catch the government and consumer's attention．

Abstract:Abstract:［Objective］ We studied the A domain of surfactin synthase in vitro to obtain new surfactin analogues．［Methods］We cloned the srfAC-A gene from Bacillus subtilis fmbj by PCR，and constructed a recombinant expression vector named pET-23a-srfAC-A． Furthermore，the SrfAC-A domain was expressed in E．coli BL21 (DE3) and purified by Ni-NTA agarose column． Then the activity of srfAC-A domain was detected． ［Results］The srfAC-A domain had specificity towards Ile，but almost no activity to other amino acids．［Conclusion］The independent A domain from surfactin synthase had selectivity to specific amino acids in vitro．

Abstract:Abstract:［Objective］We used entomopathogenic fungi to degrade insect wax．［Methods］We used four fungal strains，Lecanicilliurn lecanii V3. 4504，V3. 4505，Beauveria bassiana FDB01，and Metarhizium anisopliae TSL06．Wax coverings of female adults of Ceroplastes japonicus Green ( Insecta: Hemiptera: Coccoidea) were used as the sole carbon source in the mineral medium．［Results］All of the 4 strains could grow，eproduce，produce enzymes，and degrade wax．During a 7-day culture，the highest lipase activities of the 4 strains，V3.4504，V3.4505，FDB01，and TSL06 were 0.128±0.017，0.056±0.002，0.124±0.011，and 0.149±0.005 U/mL，respectively．The dehydrogenases activities of the 4 strains were 0.075±0.003，0.074±0.003，0.061±0.04，and 0.066±0.002U/mL respectively．The degradation rates of wax by the 4 strains were 18.20±0.019，11.00 ±0.011，15.4±0.017，and 23.10±0.031% ，respectively．［Conclusion］The 4 strains could depredate wax of C. japonicus．

Abstract:Abstract:［Objective］We screened a bacterial strain capable of degrading chlorobenzene，and purified the corresponding degradation enzyme．［Methods］ The strain was screened by gradient enrichment culture and sterile filter paper plate method，and identified by morphology and 16S rRNA gene sequence． Chlorobenzene concentration in the liquid culture was determined by gas chromatography． Degradation capability was assayed by the proportion of chlorobenzene degraded per cell． The purity quotient and molecular weight of the purified degradation enzyme were determined by gel electrophoresis.［Results］The isolated bacterium，LW13，used chlorobenzene in activated sludge as sole carbon and energy source．Cells were 2.3 μm long and 0.8 μm wide，with several terminal flagella． Strain LW13 was 95.5% similar to Lysinibacillus fusiformis，and its degradation enzyme was a positively-charged exoenzyme (molecular weight about 57 kDa)．The optimal temperature and pH of the purified enzyme were approximately 40 °C and 8.0，respectively．［Conclusion］Strain LW13 belongs to genus Lysinibacillus，and can degrade chlorobenzene (500－2000 mg/L)．

Abstract:Abstract:［Objective］ To screen glycoproteins from Campylobacter jejuni NCTC 11168．［Methods］ We introduced a screening strategy based on specific affinity between lectins and glycoproteins． First，the specific affinity between Soybean Agglutinin (SBA) and glycoproteins in C． jejuni was confirmed by western blotting． Then，magnetic beads coating with Soybean Agglutinin (SBA) were used to capture the putative glycoproteins． Putative glycoproteins were competitively eluted by N-acetylgalactosamine and separated by two-dimensional gel electrophoresis． Spots in gels were further analyzed by mass spectrometry． ［Results］A total of 22 proteins were identified by mass spectrometric analysis，of which 5 have ever been identified to be glycoproteins． Others including Cj0633 have not been proved to be glycosylated so far．［Conclusion］The method could be used to screen glycoproteins in bacteria．

Abstract:Abstract:［Objective］We screened aerobic bacteria with cellulolytic activity from ruminal fluid of sheep，cattle and camel in Xinjiang． ［Method］Fresh ruminal fluid was inoculated on sterilized sodium carboxymethylcellulose agar plates．Highly cellulolytic aerobic bacteria were screened out by using Congo red staining and liquid secondary screening culture media．The combination of morphological and biochemical test with 16SrDNA sequence analysis were used to classify the strains． Enzymatic activities of four strains with strong cellulose-decomposing abilities were studied under different culture conditions．［Results］Out 84 isolated cellulolytic strains，40 exhibited strong abilities in decomposing cellulose． They are including 37 Gram-negative isolates and 3 Gram-positive strains． Identification of these 40 strains shows that they belong to 11 species of 6 genera，16 strains in Stenotrophomonas maltophilia，10 Ochrobactrum，5 Sphingobacterium，3 Microbacterium，3 Paracoccus and 2 Pseudomonas．The results of the enzymatic studies of four strains with strong cellulolytic abilities indicates that the strains have the best enzyme producing property when straw powder was chosen as the carbon source; the pH at 5.5－6.0 and temperature at 37℃．［Conclusion］ The strains with highly cellulolytic abilities isolated from ruminal fluid show strong abilities in cellulose decomposition．

Abstract:Abstract:［Objective］ Endophytic fungi were detected and isolated from the stems，leaves，petioles and seeds of Oxytropis glabra DC sampled from Alashan of Inner Mongolia to investigate the infection rate and species distribution in different tissues．［Methods］ The endophytic fungi infection rate and distribution of species in different tissues were investigated by making temporary slides，staining，isolation and identification．［Results］Endophytic fungi were detected and observed from all parts (stems，leaves，petioles and seeds) of the plant by temporary slides staining．A total of 79 isolates were cultivated from 4 different tissues by common separation methods，which belonged to 10 genera after identification． The infection rate and separation rate were seeds＞leaves＞stems＞petioles． Undifilum oxytropis，Embellisia sp． L12 and Fusarium equiseti were the dominant species in this plant with the relative isolate frequency 77.32%，64.00% and 50.00%，respectively． ［Conclusion］Endophytic fungi were commonly found in the all parts of Oxytropis glabra DC． There was an obviously difference in quantity，species and distribution of the endophytic fungi between different parts of plant． Seeds and leaves were the most vulnerable to infection and colonization by the endophytic fungi．

Abstract:Abstract:［Objective］ To study the relationship between twin-arginine translocation system (Tat) system with the biological characteristics of enteroinvasive Escherichia coli (EIEC)．［Methods］Through homologous recombination，we constructed EIEC's tatABC gene deletion strain and complementary strain，and explored their impact on bacterial form，substrate transport function as well as on HeLa cells and guinea pig's corneal invasion force．［Results］The tatABC gene deletion strain had apparent changes in bacterial form，loss of substrate transporter function，and significant weakened bacterial invasion force (the number of the deletion strain invading into HeLa cells was decreased significantly，and the ability of its corneal lesion capacity of the guinea pig was significantly weakened)，while the complementary strain was similar to the wild strain in the above respects．［Conclusion］EIEC's Tat protein transport system is closely related with the biological characteristics of EIEC．

Abstract:Abstract:［Objective］ The aims of this study were to find out the pathogen causing high mortality of the crawfish population in Anhui over the past years．To provide the strategy for controlling the spread of the disease，an investigation was conducted to trace the origin of the pathogen．［Methods］Crawfish samples were tested by nested PCR，to diagnose the White Spot Syndrome Virus (WSSV)．Healthy crawfish were inoculated with the supernatant of tissue homogenates．The viral suspension was purified using sucrose density gradients． The gill samples infected with purified virus were then subject to the transmission electron microscopy (TEM)．The possible sources，including pond water，feedstuff，crabs，water plants，were investigated．［Results］ Crawfish samples and commercial feeds exhibited all positive for WSSV． Challenge model on healthy crawfish recovered similar symptoms as the naturally infected ones on 7 to 9 days after inoculation． The viral particles were observed under TEM．［Conclusion］ Our findings indicated that WSSV was the causative agent that led to high mortality in the crawfish population in this area．These results demonstrated that the exotic viruses are derived from the regions where the frozen feeds were contaminated with WSSV-infected shell debris．

Abstract:Abstract:［Objective］In the present report，we compared the biological characteristic of staphylococci phage GH15 and K． We also determined the therapeutic potential of the combination utility of two phages．［Methods］ The patterns of GH15 and K were detected using transmission electron microscopy．We also detected the host range and the one-step curve of phage GH15 and K．The lytic ability of mono-phage and phage cocktail was compared in vitro．Finally，the treatment effect of mono-phage and phage cocktail aginst lethal methicillin-resistant Staphylococcus aureus (MRSA) infection in mice was detected．［Results］ The length of GH15 tail was longer than that of K either in the state of contraction or noncontraction．GH15 had broader host range than K whereas both possess 7 common host strains．Although the phage cocktail had equivalent bactericidal capacity with mono-phage to most common host strains，the phage cocktail manifested more effective protection against lethal W4661 infection in mice than any mono-phage． A single smaller dose injection of phage cocktail was sufficient to protect mice effectively from fatal infection．［Conclusion］ Our results provide strong evidence towards the therapeutic use of phage cocktail as an alternative to antibiotics for acute infection caused by multidrug resistant Staphylococcus aureus．

Abstract:Abstract:［Objective］In order to study the role of porcine CD151 in infection of porcine cells by porcine reproductive and respiratory syndrome virus (PRRSV)，we established a porcine CD151 transgenic PK-15 cell line．［Methods］The full-length complementary DNA (cDNA) for porcine CD151 was amplified from porcine alveolar macrophages by reverse transcription-polymerase chain reaction (RT-PCR)，and subcloned into eukaryotic expression vector pcDNA3．The recombinant vector pcDNA-CD151 was transfected into PK-15 cells and the transgenic cell line was generated after G418 selection．Transcription of the CD151 cDNA in transgenic cell line was detected by RT-PCR and immunofluorescence．The cell line，together with control cell lines PK-15，3D4-CD163 and MARC-145，was infected with PRRSV，and the viral RNA genome or antigens in the infected cells was detected by RT-PCR or immunofluorescence．At different time points post-infection，the virus was harvested and titrated on MARC-145 cells． ［Results］The expected size of porcine CD151 cDNA was amplified with a sequence identity of 99.7% to the published sequence．From the pcDNA-CD151-transfected cell culture，a transgenic cell line PK15-CD151 was generated and correct expression of porcine CD151 was confirmed． After PRRSV infection，the viral RNA genome and antigens were detected in the cell line． Although apparent cytopathic effect was not observed in the virally infected cell line，the infectious virus with a high viral title was detected．The cell line had been passed for more than 30 generations and no significant difference in viral title was observed among generations 10，20 and 30 after PRRSV infection． ［Conclusion］Transfection of non-permissive PK-15 cells with porcine CD151 cDNA conferred the susceptibility to PRRSV infection，indicating an important role of the porcine CD151 in PRRSV infection of porcine cells．

Abstract:Abstract:［Objective］To improve the yield and quality of L-lactic acid by Rhizopus oryzae，we aim to understand the relationship between inorganic salts utilization and the L-lactic acid metabolism of the strain RLC41-6，through systematic analysis of the effects of zinc ion concentration on the production of L-lactic acid and the Lactic Dehydrogenase (LDH) activity．［Methods］ Rhizopus oryzae was cultured at 36℃ for 36h with different quantity of ZnSO4 in fermentation medium．The fermentation products were monitored by reversed-phase high performance liquid chromatography (RPHPLC)，LDH isoenzyme composition in the cell was analysed by non-denatured polyacrylamide gel electrophoresis (PAGE)．［Results］Our results showed that the concentration of ZnSO4 in medium could modulate the expression of LDH isoenzyme except LDH1，especially stimulated the expression of LDH4 and LDH5．When initial concentration of ZnSO4 is above 0.02%，the LDH4 and LDH5 reached the highest level．However，the activity of LDH was inhibited by higher concentration zinc ion in extracellular environment． When ZnSO4 concentration is 0.02%，LDH activity reaches its maximum 200 U/mL，the HPLC assay showed only L-lactic in the fermentation products (137 g/L)，while the conversion rate of glucose to lactic acid is 91%．［Conclusion］Zinc ion can regulate the metabolic processes of Rhizopus oryzae and modulate the types of the final fermentation products. An optimal concentration of ZnSO4 can not only facilitate the LDH expression but also prevent pyruvate from transformation into the malic acid and fumaric acid during the metabolism process，thereby enhance the metabolism of glucose to lactic acid of Rhizopus oryzae．