Abstract:[Objective] The GH61 family glycoside hydrolases exhibit glucan oxidative activity; they randomly oxidize glucan and thus partially destroy the crystallized structure of lignin cellulose, overcoming the major hurdle for the activity of cellulase upon lignin cellulose. In this work, a GH61 family glycoside hydrolase in Trichoderma reesei (TrGH61, previous name is endoglucanase IV) was obtained through homologous expression and purification, and its function in enzymatic degradation of lignin cellulose was studied. [Methods] The promoter of T. reesei pyvurate decarboxylase gene, the signal peptide of cellubiohydrolase, the endoglucanase IV gene, and the terminal region of the PDC gene were sequentially ligated through overlap PCR, forming the expression cassette of TrGH61. The expression cassette was then transformed into T. reesei QM9414 with the aid of plas-mid pAN7.1, and TrGH61 was homologously expressed and purified to homogeniety. The hydro-lytic activity towards cellulosic materials, the synergistic effect with cellulase and the oxidase ac-tivity were studied. [Results] Highly efficient production of the TrGH61 was achieved under the control of the PDC promoter, and the expressing level was 2.33 g/L in shake flask cultivation. The expressed TrGH61 exhibited feint endoglucanase activity, with a specific activity of 0.02 IU/mg. Moreover, it enhanced the activity of cellulase towards straw mill when it was added into the reac-tion mixture, with a synergistic degree of 1.998. Metal ions Cu2+ and Co2+, and electron donor re-duced glutathione, L-ascorbic acid, and pyrogallic acid, enhanced the activity of TrGH61 effectively. The cellulose crystallinity and degree of polymerization of rice straw were decreased by TrGH61. [Conclusion] TrGH61 can be effectively expressed with the T. reesei PDC promoter, and the puri-fied TrGH61 can act as a cellulase activity enhancer, improving the action of cellulose by destroy the crystal structure of cellulose on lignin cellulose.

Abstract:[Objective] This study aims to investigate the influence of different genetic backgrounds of Saccharomyces cerevisiae on xylose utilization of the recombinant yeast strains. [Methods] Three xylose recombinant strains designated as ZQ1, ZQ5 and ZQ7 were constructed by employing xylose reductase (XR), xylitol dehydrogenase (XDH) and xylulose kinase (XK) encoding genes via chromosome integration, and in the meantime, transcription levels of three genes and their corresponding enzyme activities as well as sugar mixture fermentation were also investigated. [Results] Gene expression levels and enzyme activities were significantly different in the three recombinant strains; in addition, xylose utilization capabilities of the three strains also varied. ZQ5 showed the highest ability in both gene expression and fermentation capability, which was followed by ZQ7, whereas ZQ1 showed the poorest xylose utilization efficiency. However, xylose utilization rate of ZQ7 outperformed ZQ5 when initial xylose concentration was 20 g/L. [Conclusion] Genetic background and initial xylose concentration exert control on xylose utilization in the recombinant strains, which should be considered in evaluation of the performance of recombinant strains.

Abstract:[Objective] Bacterium YT1305-1 was isolated and identified from biofouling biofilms. As one of the dominant bacteria in biofouling biofilms, metabolites of bacterium YT1305-1 were investigated. [Methods] 16S rRNA gene analysis, phylogenetic tree analysis and physiological and biochemical characteristics were carried on to identify the targeted bacterium. Chemical constituents of the bacterial metabolites were purified through silica column chromatography and identified using nuclear magnetic resonance (NMR). [Results] There existed dominant bacterial species in biofouling biofilms. Pseudoalteromonas sp. was identified as one of the dominant species in biofouling bacteria. 16S rRNA analysis showed P. issachenkonii was one the dominant bacterium. The targeted bacterium was named Pseudoalteromonas issachenkonii YT1305-1 and 10 chemicals were identified from its fermentation broth, including 5 Diketopiperazines (DKPs): cyclo (Gly-Ala) (1), cyclo (Pro-Gly) (2), cyclo(Pro-Tyr) (3), cyclo(Leu-4-hydroxyl-Pro) (4), cyclo (Ala-4-hydroxyl-Pro) (5) and uracil (6), thymine (7), thymidine (8), bis (2-ethylhexyl) adipate (9), phthalate esters (2-ethyl caproic) (10). [Conclusion] There existed bacterial species that were obviously dominant in quantitative terms in biofouling bioflims. Bacterium YT1305-1 was purified as one of the dominant bacterium. Analysis on its metabolites identified several DKPs, which might influence the formation of biofilms and further the development of biofouling. This investigation provides material basis for biofouling studies.

Abstract:[Objective] The objective of this study was to examine taxonomic position of one Penicillium strains isolated from central air-conditioning systems of hospitals in China. [Methods] Penicillium spores were collected on Sabourand’s agar by the 6-stage Andersen impactor. Then one strain was indetified by analysis of β-tubulin gene and morphological characters. For phylogenetic analyses in MEGA 4.0, β-tubulin gene sequences were analyzed using the maximum parsimony approach of close-neighbor-interchange algorithm, in which the initial trees were obtained with the random addition of sequences (1 000 replicates). [Results] In this study, we made a survey about fungi group in central air-conditioning systems in several hospitals in China. One new record Penicillium bilaiae SW11-6 was isolated from the central air-conditioning system in one hospital in Beijing, China, which was described and illustrated. Macroscopic and microscopic morphology was observed and described. The phylogeny of this new record and related species was constructed based on β-tubulin sequences alignment. The frequency of SW11-6 is the second one in Penicillium in the detected samples. [Conclusion] Utilizing comprehensive approaches of morphological characters and molecular identification, we concluded that we found one new Chinese record species of the Penicillium, strain SW11-6 was identified as P. bilaiae Chalabuda. And whether it will do harm to human’s health needs further studying.

Abstract:[Objective] The role of natural mediators in oxidation of anthracene and pyrene by laccase producing fungi were evaluated. [Methods] In this work, enzyme activities assay and nondenaturing PAGE were employed to analyze laccase activity. [Results] The results showed that the fungus Pycnoporus sanguineus Z-1 and Fomes fomentarius Z-5 produced laccase, with maximal production of 11.90 and 4.83 U/mL, respectively, but not lignin peroxidase and manganese peroxidase. However, the culture fluid of Fomes fomentarius Z-5, with lower laccase activity, oxidized 74.3% of anthracene and 12.4% of pyrene, higher than that of Pycnoporus sanguineus Z-1, which suggested that the natural mediators might exist in the fungal culture and influenced the anthracene and pyrene oxidation. A further experiment demonstrated that all the treatments with addition of ultrafiltrate, boiled ultrafiltrate or boiled culture fluid improved the antracene and pyrene oxidation. The enhancement levels of ultrafiltrate, boiled ultrafiltrate and boiled culture fluid from Fomes fomentarius Z-5 were higher than those of Pycnoporus sanguineus Z-1, implying that the natural mediators in Fomes fomentarius Z-5 culture was more efficient in improving PAHs oxidation than in Pycnoporus sanguineus Z-1 culture. [Conclusion] The findings indicated that natural mediators played a important role in oxidation of substrates by laccase producing fungi and these might account for the phenomenon that Fomes fomentarius Z-5 culture, with lower laccase activity, oxidized more anthracene and pyrene than Pycnoporus sanguineus Z-1 culture.

Abstract:[Objective] This study was aimed to investigate the degradation characteristics and fermentation optimization of a PCBs-degrading strain. [Methods] The capability of Sinorhizobium melilon on PCBs degradation was studied with different concentrations of 2,4,4′-TCB and 3,3′,4,4′-TCB as the sole carbon source separately. The optimum PCBs-degrading conditions were researched by orthogonal experiment and co-metabolism experiment. [Results] The degradation rate of Sinorhizobium melilon to 2,4,4′-TCB was decreased gradually with the concentration increase of 2,4,4′-TCB. The degradation rates for 2,4,4′-TCB were 93.3% of 1.0 mg/L and 65.1% with the highest concentration up to 50.0 mg/L for 7 days, respectively. The degradation rates were 56.2% of 1.0 mg/L and 22.8% with the highest concentration of 25.0 mg/L for 3,3′,4,4′-TCB, individually. The orthogonal experiment showed that the optimal conditions for degradation process were as follows: pH 7.0, temperature 30 °C, inoculation volume 4.5 mL, medium cubage 25 mL/250 mL. Under these conditions, the degradation rate of the strain was increased from 54.8% to 83.6%. In addition, the degradation rate of PCBs was increased with limonene, corvone and mannitol as co-metabolism substratesby Sinorhizobium melilon. [Conclusion] Sinorhizobium melilon is effective in degrading PCBs and our results have significant application on the study of microbial degradation and environment bioremediation of PCBs.

Abstract:[Objective] This study was to investigate the diversity of archaea from radioactive pollution environment. [Methods] Glycerin-arginine medium (GJ), Glycerin-aspartic acid medium (C1), Trehalose-creatine medium (B7), Mannitol-alanine medium (Z5), Casein-mannitol medium (CMKA), Chitosan-asparagine medium (F6), Mannitol-acid hydrolysis of casein medium (GW1), CM, HP, and KC media with different salinities were used for isolating archaea from radioactive pollution areas. Different isolates selected on the basis of morphological characteristics and Hae III digestion patterns of 16S rRNA genes. The results of 16S rRNA gene sequences were compared with sequences obtained from GenBank databases. Phylogenetic tree was constructed by the Neighbor-Joining method. [Results] Total 256 archaeal strains were obtained by different selective media, and belonged to 71 different types. They were members of Haloterrigena, Natrialba, Halococcus, Halorubrum, Halovivax, Natrinema, Natronococcus, Halobiforma, Halostagnicola, Halopiger, Natronorubrum and Haloferax genera. The similarities between detected sequences (34% of total strains) and published sequences were less than 98%. They formed distinct clades in phylogenetic tree and might represent new taxa. Haloterrigena was the dominant group. Nineteen strains were obtained by different Chitosan-asparagine medium (better isolating medium) ten-fold dilution culture. Compared with strains by Chitosan-asparagine medium, they were different groups. [Conclusion] The radioactive pollution area harbors abundant archaea, including large number of unknown bacterial groups, has a great research value.

Abstract:[Objective] Blasticidin S (BS) is a hexose-containing peptidyl-nucleoside antibiotic widely used as fungicidal in agriculture and as an effective selection reagent in eukaryotic cells. Genetic manipulation in the native producer of BS was never successful, which hinder the studies of BS biosynthesis. We recently engrafted the BS biosynthetic gene cluster into the chromosome of Streptomyces lividans and achieved heterologous production of BS. In this study, we tried to localize the boundary of BS gene cluster to identify the essential genes, providing functional insights into its remaining unknown biosynthetic steps. [Methods] PCR-targeting was used to carry out gene replacements in S. lividans-derived BS producer. The mutants were fermented and assayed by LC-MS for their capability of producing BS. [Results] We defined the boundary of the essential BS biosynthetic gene cluster that contains ten genes blsD to blsM. Disruption of blsK leads to the accumulation of demethylblasticidin S (DBS) and BS. [Conclusion] Ten genes blsD to blsM are sufficient for BS biosynthesis. BlsK was responsible for adding leucine to the β-amino group of arginine-derived side chain of DBS to form leucyldemthylblasticidin S (LDBS), There are two biosynthetic pathway for BS: DBS is directly methylated to BS; the alternative is that DBS is first converted to LDBS that is then methylated and finally hydrolyzed into BS.

Abstract:[Objective] The objectives are to identify a parasitic Hirsutella Pat. of Bombyx mori Linnaeus. and to research the spore culture of this fungus. [Methods] The comparison of morphological characteristics and internal transcribed spacer (ITS) sequence analysis were used for identification of specimens. single factor test and orthogonal test were carried out for studying sporulation conditions optimization. [Results] According to the morphological characterization and phylogenetic tree, the fungus was identified as Hirsutella satumaensis Aoki. The optimum conditions for sporulation is: peptone 3%, glucose 1%, silkworm chrysalis powder 1.5%, vitamin B1 1%, magnesium sulfate 0.05%, potassium dihydrogen phosphate 0.1%, agar 2%, distilled water 1 000 ml, 25 °C. [Conclusion] H. satumaensis Aoki, a known species in China, which microscopic characteristics were described again and the associated molecular systematics data were added in this paper. The sporulation conditions optimization could provide a reference for the spores acquisition and application of this group of fungi.

Abstract:[Objective] Aim of this study was to investigate the effect of whole peptidoglycan (WPG) from Lactobacillus acidophilus on regulating Th1/Th2 and Treg/Th17 balance in sensitized splenocytes. [Methods] BALB/c mice were intraperitoneally injected with β-Lactoglobulin (β-Lg), the sensitized splenocytes were stimulated in vitro with different doses of WPG. Supernatants were collected and measured total IgE and β-Lg-specific IgE, Th1/Th2 and Treg/Th17 related cytokines (IFN-γ, IL-4, TGF-β, IL-17) production by ELISA assay; the percentage of CD3+, CD4+, CD8+ subgroups in spleen cells were measured by flow cytometry, and the levels of T-bet, GATA-3, Foxp3 and RORγt mRNA were measured by RT-PCR. [Results] Compared with the allergy group, treatment with medium and high dose of WPG significantly decreased IL-17, RORγt mRNA response. In addition, the numbers of CD3+ and CD4+ cells and the ratio of the secretion of total IgE and β-Lg-specific IgE, Th2-type (IL-4, GATA-3 mRNA) and Th17-type (CD4+/CD8+), Th1-type (IFN-γ, T-bet mRNA) and Treg-type (TGF-β, Foxp3 mRNA) response were increased in the splenocytes stimulated with WPG in a dose manner. [Conclusion] Treatment with WPG from Lactobacillus acidophilus could regulate the imbalance of Th1/Th2 and Treg/Th17 in allergic spleen cells.

Abstract:[Objective] The composition and diversity of intestinal microbial diversity of Chinese giant salamander (Andrias davidianus) were investigated. [Methods] The composition and diversity of intestinal microbial diversity of Chinese giant salamander were analyzed by culture-independent method. The total DNA were extracted by Fecal DNA Isolation Kit of Mo Bio company. The 16S rRNA gene of intestinal microbial diversity of Chinese giant salamander were amplified by universal PCR primers. Positive clones were analyzed by PCR restriction fragment length polymorphism (PCR-RFLP) and the clones with unique Hae Ⅲ patterns were selected for sequencing and constructing 16S rRNA gene phylogenetic tree. [Results] A total of 101 positive clones that randomly screened from the library were fall into 28 operational taxonomic units (OTUs) based on the result of Hae Ⅲ digestion and sequencing. These clone squences were divided into 4 phyla with phylogenetic analysis, which consisted of the Proteobacteria, Clostridia, Bacilli and Chlamydiae, of which Proteobacteria accounting for 92.08% of the total number of clones was the absolutely dominant group. Sequence alignment showed these clone sequences have high similarities with 20 genus that had been reported. In addition, one OTU on phylogenetic tree is independent and failed to determine its classification. [Conclusion] The intestinal microbial diversity of Chinese giant salamander harbors a diversity endophytic bacterial and maybe existence new OTUs.

Abstract:[Objective] In order to obtain some thermo-tolerant strains of Lentinula edodes, the original strain 18 was mutated by UV induced protoplast mutagenesis. [Methods] The protoplasts of 18 were exposed to ultra-violet ray and the mutants were screened through the recover ability of mycelia after being treated at 47 °C for three hours. The growth rate of mycelia in sawdust medium during constant temperature process (25 °C), high temperature process (30 °C) and recover process (25 °C ) were determined. And the fruiting bodies of the mutants were collected at 25 °C. [Results] Fifty-seven thermo-tolerant mutant strains of 18 were obtained, and N6, N44 and N24 got good comprehensive properties. The growth rate during constant temperature process, high temperature process and recover process had correlation with fruiting characteristics. The growth rate during the recover process had positive correlation with fruiting production, single mushroom traits and high temperature tolerance capability, and it was selected as the predictor of integrated traits of thermo-tolerant mutant strains. [Conclusion] Basing on UV induced protoplast mutagenesis, some new thermo-tolerant mutant strains of Lentinula edodes were obtained.

Abstract:[Objective] To optimize the fermentation medium of an antitumor endophytic fungus isolated from Ginkgo biloba. [Methods] In this study, the dry weight of mycelia, weight and antitumor activity of crude extract were used as standards to screen out the best carbon source and nitrogen source through single factor experiment. Then the culture medium recipe was optimized by the orthogonal test in five factors and four levels. [Results] The best culture medium recipe was: glucose 45 g/L, peptone 8 g/L, K2HPO4 0.5 g/L, MgSO4·7H2O 0.2 g/L, KCl 1 g/L, FeSO4 0.01 g/L. After optimization, the dry weight of mycelia, weight and antitumor activity of crude extract were increased by 41.88%, 226.52% and 19.31% respectively. [Conclusion] The production and antitumor activity of crude extract was significantly increased after optimization, which might be beneficial to reduce the fermentation scale and workload in scale up fermentation later.

Abstract:[Objective] Data from ample studies support the idea that the immune homeostasis is crucially dependent on a cross-talk between host immune system and enteric flora in which the host recognizes and responses distinctively to probiotic and pathogenic bacteria. The toll-like receptors (TLRs) and microorganism associated molecular patterns (MAMPs) may play a major role in the host discrimination between probiotics and pathogens, as the recognition of MAMPs by TLRs can activate innate immune response and prime the adaptive immune system. In the TLRs family, TLR5 that responds to flagellin is the only protein-binding TLR, it’s much easier to study the flagellin-TLR5 interaction structurally and functionally. The overall aim of this study was to test for a possible contribution of the flagellin-TLR5 crosstalk to the host discrimination between probiotic and pathogenic bacteria. [Methods] Using flagellin protein sequences from probiotic and pathogenic bacteria living in gastrointestinal tract, we firstly constructed a phylogenetic tree of flagellin proteins and then aligned the flagellin protein sequences in TLR5 recognition region between probiotic and pathogenic bacteria. [Results] We found that probiotic and pathogenic bacteria differed in flagellin protein sequence, particularly in the TLR5 recognition sites. [Conclusion] Acclimatization to TLR5 recognition may result in the different TLR5 recognition sites on flagellin between pathogens and probiotics. Moreover, previous studies show that stimulation of basolaterally expressed TLRs results in inflammatory response, but activation of apically expressed TLRs leads to inhibition of the proinflammatory response. Altogether, our findings provide preliminary but encouraging evidence for the existence of crosstalk between flagellin and TLR5 which may be one of the mechanisms for the host discrimination between probiotics and pathogens.

Abstract:[Objective] To detect and analyze linear plasmids from rare actinomycetes species. [Methods] Rare actinomycetes strains were isolated from plants, and linear plasmids were detected, sequenced and analyzed. [Results] An endophytic actinomycetes strain 25L-1-1c was isolated from Chinese herb Peucedanum decursivum. Its 16S rRNA gene sequence resembled Nocardiopsis. Strain 25L-1-1c harbored a linear plasmid pNPL1. The telomere of pNPL1 was cloned and sequenced, which was a novel sequence containing multiple palindromes. The complete nucleotide sequence of pNPL1 comprised 24 621 bp, encoding 22 genes, 2 of them resembling Streptomyces telomere replication genes, one major plasmid transfer gene, and others unknown functional genes. Plasmid containing the Nocardiopsis telomere replication genes could not propagate in S. lividans, indicating that development of Nocardiopsis genetic system is needed. [Conclusion] This is the first example of linear plasmid in Nocardiopsis.

Abstract:[Objective] The visual antibody array for rapidly detecting Escherichia coli O157:H7 and Samonella typhimurium was built. [Methods] Combined with immunology and protein chip technology, Based on double antibody sandwich assay principle. Used high-throughput protein chip and visualization technology, the method for simultaneous detecting E. coli O157:H7 and Salmonella typhimurium has been selected, and only one sample was used. [Results] The test results couble be visible to the naked eye, the detection of time was as short as 90 min. The sensitivity of pure broth was 105 CFU/mL and artificially contaminated food was 106 CFU/mL. The sensitivity was coincided with conventional ELISA and had good detection specificity and repeatability. [Conclusion] The visual antibody array couble be examined by naked eye, which owned high-throughput detection, easy operation, low cost of detection and didn’t need large equipment. The study showed a satisfactory prospect and provided a new rapid assay for detection of Pathogenic microorganisms.

Abstract:Biofilm is the predominant form of life for bacteria in environments. The highly structured, matrix-enclosed, and functionally coordinated community protects bacterial cells from inhospitable environment. Biofilm-mediated pollution control has become an attractive approach in environmental engineering. In this review, the mechanisms through which bacteria interact with material surfaces and develop into biofilms in various environments are summarized; focuses are on the roles of pioneer bacteria in biofilm development, the dynamic changes in bacterial community composition, and the resistance to stresses as well as pollutant degradation characteristics of biofilms in unfavorable environments.

Abstract:High concentrations of hydrogen sulfide are generated during wastewater and sludge treatment processes. Thiobacillus denitrificans is an important desulfuration engineering bacterium capable of oxidizing hydrogen sulfide and other sulfides. The current article reviews the biological characteristics of Thiobacillus denitrificans and two pathways of hydrogen sulfide oxidization. Factors, e.g. sulfide load, nitrate or nitrite concentration, oxygen content and pH value, influencing oxidation efficiency, reaction velocity, pathway and form of products are summarized. The application of Thiobacillus denitrificans in odor removal is introduced and its potential use in simultaneous control of nitrogen- and sulfur-containing odor-causing substances is also discussed.

Abstract:Adhesion of bacteria to an oil-water interface have been mainly applied to bioremediation of hydrocarbons pollution, oil exploitation and refining, food processing and etc. The related studies have aroused widespread interest among researchers. The paper firstly elucidates the mechanism of bacterial adhesion to oil-water interface, which is based on extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory, and then the effects of cell surface properties, oil phase and water phase on bacterial adhesion. Finally, it introduces a few applications of bacterial adhesion in Microbial Enhanced Oil Recovery (MEOR), bioemulsification, biodemulsification, and biodegradation of hydrocarbons. The further research directions in this field are also proposed.

Abstract:Norovirus is one of the main pathogens causing human nonbacterial gastroenteritis. Due to its high infectivity and variability, norovirus could lead to a serious public health problem, especially in the people with weak resistance. Therefore, it is important to develop rapid and accurate detection technique on preventing and controlling norovirus. This article reviews recent technology application and development trends in the detection of norovirus, such as RT-PCR, loop mediated isothermal amplification, real-time fluorescence quantitative PCR, nested PCR, ELISA, immunochromatography, and gene chip.

Abstract:Aflatoxin (AFT) contamination caused by Aspergillus flavus, a saprophytic aerobic fungus, in several crops such as peanut, maize and cottonseed is considered as the most serious factor influencing food safety concerning animal and human health worldwide. Whole genome sequences of A. flavus have been released and the genome size is about 37 Mb on 8 chromosomes encoding over 13 000 functional genes. In the whole genome sequences of A. flavus (NRRL3357), 55 putative secondary metabolite clusters have been identified based on backbone enzyme gene analysis by SMURF, and only three secondry metabolite clusters including AFT, cyclopiazonic acid (CPA) and aflatrem have been characterized. The above three secondary metabolite clusters are regulated by different environmental factors, secondary metabolite regulators, enzymatic activity, oxylipin and quorum sensing. AFT, CPA and aflatrem biosynthesis are inhibited by the global regulators, LaeA and VeA, in secondary metabolism. A family of oxylipin-producing oxygenases and their products encoded by ppo and lox can regulate sclerotia and conidia production and secondary metabolism in A. flavus. The profile of secondary metabolites could be influenced by variation of fungi density because higher fungi density will induce higher sporulation with decreased AFT. Most strains of A. flavus can produce numerous hydrolytic enzymes including α-amylases, pectinases, proteases, and lipases, which are believed to be important for fungal infection and virulence to host tissue. Further research on regulation of secondary metabolism and mycotoxins produced in A. flavus are also discussed.

Abstract:The teaching content of Genetic Engineering experiment is determined by the task for the order class. The teacher should make vocational skill training by skill breaking-down model, differentiation teaching model and task-driven model, as well as emphasize the cultivation of vocational quality such as carefulness, strictness, patience, the ability of comparison and analysis, etc. The practice has testified that this is beneficial to the cultivation of strong experiment skills, enhancing vocational capability, and improvement of enterprises’ satisfaction.

Abstract:Fermentation Engineering is one of the most important practicality specialized course for undergraduates majoring in biological engineering specialty, and the teaching quality has critical effects on students’ professional ability for their practical work after graduated. For the purpose to improve the teaching efficiency and enhancing the practical experience on fermentation engineering, the teaching ideas, methods, and functional partition were explored and practiced. Based on the content, the course was divided into four unites including fermentation equipments, solid fermentation, liquid fermentation, and the products isolation. Based on the fermentation technology, the experiment course was practiced peculiarity with the whole procedure of wine fermentation in laboratory. And the technical training was accomplished in fermentation workshop. Based on the lecture module, the course was accomplished in classroom, laboratory, and workshop by professor of the university, professionally engineer of the industry, and laboratory technician. The stereoscopic teaching system consists of basic theory studies, operation exercises, and workshop engineering practices, were constructed and practiced for three years with more than 240 peoples. The results indicated that this was helpful for their social practice ability and enhance innovative competence.

Abstract:[Objective] To elucidate the relative polarity and stability of seven carotenoids accumulated in normal spirilloxanthin biosynthesis pathway of anoxygenic phototrophic bacteria (APB) by thin-layer chromatography (TLC). [Methods] We investigated the changes in polarity, characteristic absorption spectra and stability of seven carotenoids accumulated in spirilloxanthin biosynthetic pathway of Rhodopesudomonnas palustris CQV97 by TLC, image gray intensity analysis, absorption spectroscopy and HPLC analysis. [Results] Strain CQV97 accumulated seven types of carotenoids including lycopene (C1), rhodopin (C2), 3,4-didehydrorhodopin (C3), anhydrorhodovibrin (C4), rhodovibrin (C5), OH-spirilloxanthin (C6) and spirilloxanthin (C7), the seven carotenoids were clearly separated by TLC. The relative polarity of seven carotenoids on TLC plate changed in the order of C1C3 ≈C7>C5≈C4≈C1≈C6. In darkness, the seven carotenoids were stable within 90 min. [Conclusion] TLC was capable of resolving clearly all seven carotenoids accumulate in spirilloxanthin biosynthetic pathway of APB. The seven carotenoids on TLC plate were sensitive to illumination and short-term stable in darkness. The results will be helpful for rapid identification of carotenoids by TLC.

Abstract:[Objective] To evaluate the efficacy of chromogenic medium for Escherichia coli O157:H7. [Methods] A new Escherichia coli O157 chromogenic medium (HKM) was compared with CHROMagar, BioMerieux, Domestic company and CT-SMAC for detection of Escherichia coli O157 by reference strains, artificially contaminated samples and natural samples. [Results] The selectivity, highly specificity and detection efficiency of HKM were as same as that of CHROMagar, and were better than that of BioMerieux, Domestic company and CT-SMAC. [Conclusion] The HKM E. coli O157 chromogenic medium has a good effect and invaluable in detecting E. coli O157:H7, because it has high specificity and selectivity.

Abstract:[Objective] Mixed methane-oxidizing bacteria are useful for reduction of methane emission. For research and application of mixed methane-oxidizing bacteria, their long-term stable preservation must be first solved. The preservation methods should be able to maintain the integrity and stability of the community structure and function. [Methods] Two kinds of stable mixed methane-oxidizing cultures enriched from a coal mine soil were used as the bacterial community. Four preservation methods, refrigeration, ultralow freezing, freezing in paraffin oil and freezing in glycerin, were comparatively studied. The growth, MMO activity and community structure before and after the preservation were investigated. [Results] The method with glycerin could not be used for mixed methane-oxidizing bacteria preservation. After preservation using the other three methods, the cell density, methane oxidation capacity, MMO activity and subculture stability reached the same level as before the preservation. DGGE fingerprints of 16S rRNA for the mixed cultures before and after the preservation showed that the change of the community structure during the preservation was not much. [Conclusion] The three preservation methods can effectively maintain the function and community structure of the mixed methane-oxidizing bacteria stable.

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Abstract:[Objective] We studied whether avermectin productivity could be affected by other polyketide biosynthetic gene clusters in Streptomyces avermitilis genome. [Methods] By constructing gene knock-out cosmids or plasmids and introducing into industrial host, 10 mutants were obtained after screening double crossover colonies from conjugants of each polyketide gene clusters knocked-out vectors. [Results] Avermectin productivities of seven polyketide null mutants were higher than that of the starting strain. Two mutants abolished avermectin production. Three mutants with combined knock-out of two of three strong effect clusters had no further increase on avermectin productivity. [Conclusion] Deletions of some polyketide gene clusters can be used to increase avermectin productivities in Streptomyces avermitilis. The results also suggested that there were interweaved networks among these polyketide gene clusters in Streptomyces avermitilis.

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