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Abstract:[Objective] The research was conducted to study on the bacterial community diversity and dominant population in Xinjiang akesu area and the correlation with the environmental factor. [Methods] The bacteria diversity and dominant population was analysis by PCR-denaturing gradient gel electrophoresis (DGGE), cloning, sequencing and the DGGE sequence analysis and the canonical correlation analysis (CCA). [Results] The sequencing of the dominant population showed that there were 29 sequencing belong to the un-cultivation microbial, and the other 43 DGGE band were made up by 9 order: Myxococcales, Pseudomonadales, Rhizobiales, Bacillales, Burkholderiales, Actinomycetales, Oceanospirillales, Flavobacteriale, Alteromonadales. [Conclusion] Canonical correlation analysis (CCA) result showed that microbial community structure and environmental factors were closely related in saline-alkaline soils.

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Abstract:[Objective] Cloning of β-glucosidase gene bglB from Geobacillus thermodenitrificans, heterologous expression in E. coli, purification and characterization of its enzymatic properties. [Methods] Molecular cloning of the β-glucosidase encoding gene (bglB) from Geobacillus thermodenitrificans was performed by using a PCR technique. The gene was expressed in BL21(DE3) of Escherichia coli. After purification, the enzymatic properties and the protein aggregation of β-glucosidase was investigated. [Results] The optimum temperature and optimum pH of the recombinant β-glucosidase are 65 °C and 7.0 respectively, the enzyme is stable for 4 h under the conditions of pH 5?10, 60 °C, and it maintains its high enzymatic activity at the high salt concentration (up to 880 mmol/L K+). The recombinant β-glucosidase is strongly activated by Al3+, while slightly inhibited by Co2+. Under the optimal reaction condition, the enzyme specific activity of recombinant β-glucosidase is 0.043 IU/mg. The β-glucosidase GST fusion protein exists in different oligomers by a Superdex G-200 gel filtration analysis, and the different oligomers of enzymes all have hydrolase activity. [Conclusion] We successfully obtained a heat- and salt- resistant neutral recombinant β-glucosidase from Geobacillus thermodenitrificans, and paved a way for further study of its catalytic mechanism and improvement its thermal stability of beta-glucosidase.

Abstract:[Objective] In order to obtain plant growth promoting strains of production 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, nitrogen fixation, phosphate solubilization, and production of indoleacetic acid and siderophore. [Methods] 98 rhizobacteria from Jatropha curcas L. were isolated by the method of grinding separation and 28 isolates were selected for the detection of plant growth promoting index of production ACC deaminase, nitrogen fixation, phosphate solubilization, and production of indoleacetic acid and siderophore. [Results] The results showed that 46% of the isolates produced ACC with the maximum ACC deaminase was 128.308 μmol α-KA/(mg·h), 68% of the isolates produced IAA, 54% had nitrogen fixation ability and 32% of them had phosphate solubilization ability. Some of the representative isolates were seleceted for the 16S rRNA gene sequencing and analyzing. The representative strains belonged to 8 different genera including Bacillus, Arthrobacter, Pseudomonas and Alcaligenes, with Bacillus as the predominant genus (50%). Phylogenetic analysis demonstrated that strain KLBMP 4817、KLBMP 4821 and KLBMP 4824 could be potential novel species of the genera Stenotrophomonas and Paenibacillus. [Conclusion] The rhizobacteria of Jatropha curcas L. in Panzhihua City contain a variety of bacteria as well as source of new taxa. Some of them had the ability of plant growth promoting. Among them, strain KLBMP 4804 (Bacillus) had the strongest ACC deaminase activity. Strain KLBMP 4820 (Bacillus) had the strongest ability of IAA production respectively.

Abstract:[Objective] E. coli DH5α modified the valine biosynthesis pathway to biosynthesize isobutanol. [Methods] The 2-ketoisovalerate decarboxylase gene (kivD) and alcohol dehydrogenase gene (adhA) of Lactococcus lactis 1.2829 were tandemly cloned and expressed in E. coli DH5α. [Results] The yield of isobatanol by the engineered E. coli was only 0.12 g/L by 24?h fermentation. Further results revealed that the insufficient KivD activity is the bottleneck for the isobutanol biosynthesis. A series of experiments also showed that the optimal temperature and pH for both KivD and AdhA are 30 °C and pH 6.5, respectively. [Conclusion] Isobatanol fermentation by cloning and expressing essential genes in host is feasible.

Abstract:[Objective] To increase ester content and maintain fermentation performance, mixed fermentation of Saccharomyces cerevisiae and Pichia anomala in wheat bran liquid medium were used. [Methods] S. cerevisiae and P. anomala were inoculated using mixed or sequential modes. Fermentation efficiency and the content of ethyl acetate during fermentation process, and volatile compounds in ultimate fermentation liquid were detected with pure culture of yeast as controls. Interactions between yeasts were preliminarily studied through cell-free systems. [Results] Using sequential inoculation, growth of P. anomala wasn’t inhibited by S. cerevisiae and two species could reach high biomass. At the end of fermentation ethanol content was 20.17 g/L, which reduced 9.14% than pure culture of S. cerevisiae. But the concentration of ethyl acetate was 0.74 g/L, which increased 80% compared to P. anomala monoculture. The mixed fermentation of S. cerevisiae and P. anomala produced more esters, less alcohols and fatty, and improved flavor characteristics of fermentation liquid. Analysis of cell-free system showed that carbon source was an important factor to affect growth of S. cerevisiae and metabolites obviously inhibited propagation of P. anomala. [Conclusion] Mixed fermentations of S. cerevisiae and non-Saccharomyces provided a feasible way to improve flavor complexity and obtain speci?c characteristics of fermentation products.

Abstract:Bifidobacterium lactis V9 (B. lactis V9) has been demostrated as a probiotic with well properties and stable genetics. The gas composition in environment of industrial manufacturation is positively associated with viable numbers of probiotic and nextly have influence on probiotic properties. [Objective] The influence of different gas environment on the growing of B. lactis V9. [Methods] By MRS agar plate, liquid MRS medium and pasteurized skim milk inoculated with B. lactis V9. [Results] On the MRS agar plate, the numbers of B. lactis V9 forming colonies under mixed gas environment (N2:H2:CO2=80:10:10) was more than nitrogen gas environment (N2: 99.99%) and few colonies formed under normal air environment (N2:O2≈79:21). In the MRS liquid medium for 24 h, the viable counts under mixed gas were 9.11±0.11 log CFU/mL which was significantly higher than growing in normal air condition with 8.04±0.10 log CFU/mL (P<0.01). Moreover, the acetate and lactate production under mixed gas condition were respectively significantly higher than normal air condition (12.79±0.86 mmol/L VS 11.99±0.73 mmol/L, 0.65±0.07 mmol/L VS 2.75±0.57 mmol/L, P<0.01). In addition, the acetate/lactate molar ratio was 1.06:1 and 0.24:1, respectively. After 18 h of pasteurized skim milk fermentation, the reduced pH of fermented milk under mixed gas condition was significantly lower than normal air condition (4.48±0.07 VS 5.03±0.12, P<0.01). The viable counts under mixed gas were 9.02±0.15 log CFU/mL which was significantly higher than growing in normal air condition with 8.53±0.08 log CFU/mL (P<0.01). The acetate and lactate production under mixed gas condition vs. normal air condition in fermented milk were 60.52±2.30 mmol/L and 5.17±1.02 mmol/L VS 16.86±0.34 mmol/L and 5.92±0.81 mmol/L, repectively. The acetate/lactate molar ratio was 11.71:1 and 2.85:1, repectively. [Conclusion] These study suggested that mixed gas condition with N2:H2:CO2=80:10:10 was beneficial for B. lactis V9 growing in liquid medium and pasteurized skim milk fermentation increased by 0.5?1 grade of viable counts during the same time. It can provide instruction for preparation of probiotic fermented milk and viable bacterial counting of B. lactis V9.

Abstract:[Objective] The aim of the present study was to identify the genera and screen potential characteristics bacteria in the lactic acid bacteria isolated from koumiss. [Methods] The characteristics of lactic acid bacteria were studied by the experiments on some aspects, such as morphology, physiological and biochemical characteristics, molecular biology and the inhibition of pathogenic bacteria. [Results] There were two strains of Lactobacillus plantarum, two strains of Enterococcus villorum, two strains of Enterococcus dispar, three strains of Enterococcus durans and one strain of Enterococcus raffinosus. The tested bacteria had different degrees of inhibition to Staphylococcus aureus, Escherichia coli and Enteritidis bacillus. [Conclusion] HZ24 and HZ25 were good potential probiotics which may make great contributions to food fermentation industry.

Abstract:[Objective] The efficacy of the CP7 antimicrobial proteins (CP7ACP) to Aeromonas hydrophila was evaluated to provide potential novel natural drug for treating fish disease caused by Aeromonas hydrophila. [Methods] The effect on Growth, phosphorus divulges and biomacromolecule of Aeromonas hydrophila S12 were tested using Antibacterial test, Mo-Sb colorimetry and UV spectroscopy, while destructive effects of Aeromonas hydrophila cell structure by CP7ACP were observed under both scanning electron microscope and transmission electron microscope. [Results] The inhibition zone diameter was about 8.1 mm, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was 1/8 and 1/4 of stock solution respectively. After treated by CP7ACP, electron microscope reveals that cell wall, membrane, organelles and the thallus of Aeromonas hydrophila are subject to different degrees of damage, while intracellular biomacromolecule and phosphorus significantly divulge, genomic DNA become hyperchromic effect. [Conclusion] CP7ACP inhibit the growth of Aeromonas hydrophila, can be used for preventing fish disease caused by Aeromonas hydrophila.

Abstract:[Objective] Improve the detection rate of Coxiella burnetii (C. b) Com1 gene by quantitative PCR and nested PCR; determine the food safety of egg yolk by Coxiella burnetii Com1 gene detection, which has great magnificence for Coxiella burnetii epidemiology. [Methods] Extract DNA in chicken eggs, determine the Com1 gene by quantitative PCR and nested PCR, and sequence the PCR products. Observe the microorganism in chicken blood leukocytes by indirect immunofluorescence. [Results] Results showed that over 4 Com1 genes were detected by quantitative PCR and nested PCR, and the amount of Com1 genes in chicken eggs reached 104?106 with the positive rate of 5%?22%. The sequencing results of PCR products showed that there were variant strains in positive chicken eggs. Immunofluorescence observed the microorganism Coxiella burnetii in chicken eggs. [Conclusion] Therefore we draw the conclusion that the microorganism Coxiella burnetii exists in chicken eggs and it may be the source of infection of Q fever.

Abstract:[Objective] To test filamentous fungi antifungal susceptibility, this study determined the minimal inhibitory concentration (MIC) values of 6 antifungal agents: Itraconazole (ITC), Ketoconazole (KET), Voriconazole (VRC), Ciclopirox (CIC), 5-Flurocytosine (5FC), Fluconazole (FLU) to the strain Paecilomyces hepiali which usually used in health food industry. [Methods] Method of Clinical Laboratory Standards Institute (CLSI) M38-A2 ＜Reference Method for Broth Dilution Antifungal Susceptibility Testing of Filamentous Fungi; Approved Standard—Second Edition＞ was referred. [Results] The results showed that the quality control strain Candida parapsilosis ATCC 22019T MIC values were within the reference range, the strain P. hepiali MIC values for the 6 antifungal agents were 1 mg/L, 0.5 mg/L, 0.25 mg/L, ≥128 mg/L, 64 mg/L, 2 mg/L respectively. [Conclusion] M38-A2 method could be applied to determine the susceptibility of P. hepiali to antifungal agents. But, more tests needed to acquire the standard interpretation of the strains susceptibility.

Abstract:[Objective] The evolutionary tendency and molecular characteristics of both HA (Hemagglutinin) and NA (Neuraminidase) gene of seasonal H3N2 subtype influenza viruses isolated in 2010-2011 were to be determined, and the molecular information made an important part of control and prevention of influenza worldwide. [Methods] We collected all nucleotide sequences of segment 4 and 6 that contained complete ORF (Open Reading Frames) of HA and NA gene during Jan-2010 and Sep-2011, phylogenetic trees based on ORF sequences of two genes were constructed. Theoretical amino acid (aa) chains of every sequences were deduced to find out the variation sites referring to vaccine strain, and prevalence of changes in functional positions were analyzed. [Results] Among all 267 sequences surveyed, 3 (2 HA and 1 NA) were strains of swine origin, while others could be classified into 2 groups by evolutionary relationships. Compared with vaccine strain, average variation sites on HA and NA antigenic determinant were 5.33 and 2.01, respectively. Sites mutations on RBS (Receptor of Bonding Sites) and HA disulfide as well as NA drug resistant sites were found in 3 different isolates. N-glycosylation sites of HA and NA were increased in most isolates. Besides, variation sites on HA antigenic determinant between isolates from Jiangsu and Guangdong were accounted from 7 to 13. [Conclusion] Two kinds of gene evolutionary characteristic were found in recent seasonal H3N2 subtype viruses. Antigenic difference between epidemical strains and vaccine strain are recommended for development of new vaccines, in spite of they were still unknown, the variations on antigenic positions and N-glycosylation sites between each isolates and vaccine strain would probably alter antigenic characteristics of most isolates surveyed, so further antigen detection work is required to be carried; Health administrative departments in different districts must improve the treatment followed drug resistance situation of local epidemical strains.

Abstract:[Objective] We used different root and rhizosphere soils in Weinan, Xianyang, Ankang, Shangluo and Yulin, Shaanxi province of China to isolate plant growth promoting rhizobacteria (PGPR), and then studied the mechanism why they can promote the growth of plants. [Methods] Preliminary screening of PGPRs under the premises of PGPR may having the abilities of phosphate solubilization, N2-fixing, production of NH3 and indoleacetic acid (IAA) and antagonistic activity against three common pathogenic fungi. After that, multiple plant growth promoting activities were detected, maize growth enhancement by plant inoculation studies with these isolates alone individually and the mixture of each isolates under pot experiment conditions. [Results] In total of 158 strains were isolated. 17 of which have mechanisms and a striking plant growth promoting activity with respect to various plant parameters. Under pot culture conditions, compared with the control, the results showed that the strain which inoculated in combination was significant increase than inoculated alone, which in shoot length, root length, stem length, average diameter of stem and plant dry weight, respectively. [Conclusion] Isolates with multiple PGP activities can also be rhizospheric competent, providing promising isolates for PGPRs combination to resolve the challenges in field application of PGPR.

Abstract:In eukaryotes, histone modifications that induce chromatin remodeling are an important mechanism of epigenetic regulation, and acetylation is a crucial form of such modification. In general, the ε-amino groups of lysine residues of histone N-termini are subject to acetylation, which affects the structure of nucleosome. The acetylation status of histones is controlled by two kinds of functionally antagonistic enzymes, acetyltransferases and deacetylases, which are responsible for acetylation and deacetylation of histones, respectively. Each enzyme has several homologs in the cell that modify different residues of histones. Furthermore, combined with other factors, histone acetylation regulates gene expression at the epigenetic level. In this review, we summarized latest research on the classification of acetyltransferases and deacetylases together with their functional characteristics regarding gene regulation in the eukaryotic model organism Saccharomyces cerevisiae.

Abstract:Polyamide nucleic acid (PNA) molecules are DNA mimics with neutral acrylamide bonds as tskeleton. PNA could combine specifically with targeting DNA and the PNA-DNA duplex exhibits higher thermal stability than the corresponding DNA-DNA duplex. Due to their specific structure and characteristics, PNA probes have recently been developed and applied to a variety of microbiological diagnostication fields, such as food, environmental and clinical assay, which go above and beyond the possibility of DNA probes. Here we summarize the recent application of PNA probes in the realm of microbiological diagnostication.

Abstract:Serum complement system is the signi?cant barrier to the development of baculovirus vectors for therapeutic gene delivery. This paper gave a review to the efforts taken to avoid complement attack. Selecting the immunoprivileged tissues as target for baculovirus-mediated gene delivery, such as eye, brain and testis. ex vivo transduction is a widely used approach to exclude the complement attack. Using of pharmacological inhibitors of complement as well as surface engineering of the baculoviral vectors through the use of synthetic polymers, pseudotyping or display of complement inhibitors can inhibit complement attack efficiently. This will signi?cantly increase the possibility of using baculovirus vectors for therapeutic applications.

Abstract:Food spoilage caused by the bacterial biofilm is a signi?cant problems in food industry. It is indicated that quorum sensing of the bacteria plays a major role in bio?lm formation and food spoilage. This review focuses on the recent research advances about various quorum-sensing signaling molecules produced by bacteria, the role of signaling molecules in bio?lm formation and the signi?cance of bio?lms in food industry. As quorum-sensing signaling molecules are closely relate to food spoilage, it was also reviewed that quorum-sensing inhibitors can be developed to be used as novel food preservatives for enhance shelf life and food safety.

Abstract:To the factual situation during the General Biology course teaching, we put forward and discuss the new teaching and studying method which is based on some practical problems. The goals of the new studying method for students are to change the passive studying to active studying by changing the thinking way, and to construct their systematic knowledge through changing studying method. During the General Biology course teaching, we try our best to promote the course teaching level by the students’ vision expanding and communication between the teacher and students. All the above lecture innovation and practice during the General Biology course have promoted the teaching level and good studying ability in the specialty for the students.