Abstract:

Abstract:The white rot fungus Trametes sp. SQ01 secretes a high level of laccase in the basal liquid medium without induction. The laccase has been purified to homogeneity through acetate acetone precipitation and DEAE-cellulose 52 anion-exchange chromatography with a final purification fold of 15.4 and an overall yield of 43.6%. The purified enzyme was identified with a molecular mass of 62 kD by SDS gel electrophoresis. The purified enzyme was not blue like the typical laccase but yellow, and had not the basic spectroscopic features of a typical blue laccase. The enzyme oxidized a series of diphenol, creosol and non-phenol, including 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonate) (ABTS), catechols, hydropuinone, 2,6-dimethoxyphenol (DMP), and guaiacol. With ABTS as a substrate, the optimum pH and temperature for the purified laccase were 4.5 and 70°C, respectively. The enzyme was highly stable in the pH range 3~11, and the most stable under the pH 5.0. The enzyme was stable up to 50°C, and had half-life of 30 min at 60°C. The susceptibility of laccase towards several surfactants, inhibitors and metal cations was also assessed. The enzyme activity was completely inhibited by DTT at the concentration of 1 mmol/L, but 1 mmol/L of SDS activated the laccase activity by 128%. Laccase activity was also inhibited by several metal cations at a 5 mmol/L of concentration, especially Mn2+. The purified enzyme efficiently decolorized Remazol Brilliant Blue R (RBBR) in the absence of added redox mediators. The high production of Trametes. sp. SQ01 laccase as well as its decolorization ability demonstrated its potential application on dye decolorization.

Abstract:Sphingomonas sp. TP-3 synthesizes a type of novel biopolymer Ss with properties of thickening, pseudoplastic, gelling and emulsification. Both single factor experiments and uniform design were employed in this study to optimize fermentation conditions of strain TP-3. The optimal fermentation paramenters in shaking flask were as follow: glucose 41.2 g/L, soybean meal 2.0 g/L, NaCl 0.85 g/L, K2HPO4 1.46 g/L, MgSO4 0.12 g/L, MnCl2 0.0075 g/L, FeSO4 0.002 g/L, initial pH 7.0, culture temperature 27°C, rotating speed 180 r/min. The yield of biopolymer Ss reached 21.5 g/L. As a low-cost biopolymer, Ss has wide prospect for application in oil recovery.

Abstract:The degradation of nitrobenzene(NB) using a combination of Fe0 and anaerobic microorganism was studied. Nitrobenzene could be degraded effectively and the synergistic effect between Fe0 and anaerobic microorganism was apparent, and the nitrobenzene removal efficiency increased with the increasing of Fe0; the optimum pH was 5.0~6.0; as co-metabolizing substrate, glucose could promote the degradation of nitrobenzene; In case of high concentration of Fe2+ and Fe3+, the anaerobic biodegradation activity of nitrobenzene were inhibited in a certain degree; 0.5 mg/L Fe2+ and Fe3+ were the optimum to accelerate biodegradation rate of nitrobenzene; the degradation kinetics of nitrobenzene were followed by first-order reaction, reaction rate constant reduced along with the concentration of nitrobenzene increased.

Abstract:The simulated activated sludge system was set up to treat the oilfield produced water after physical-chemical treatment in this study. The molecular methods such as PCR-DGGE and sequencing were applied to study population dynamics and diversity of yeast during system starting up and running. The result indicated that both in the influent and activated sludge showed higher yeast diversity. And yeast diversity increased during system running. It suggested that yeast would exist in the sludge and contribute to COD removal. And also yeast would perform well in hydrocarbon transformation and pollutant removal.

Abstract:The main pollution of coastal sea is heavy metal and eutrophication, which resulted in degeneration of its eco-function. Pollution of heavy metal is accompanied with eutrophication in sea water. This article studied on copper absorption capacity of several bacteria strains which were isolated from the surface of macroalga Gracilaria lemaneaformis that was cultivated in copper polluted sea. We got 6 strains of epiphytic bacteria from the seaweed, Ochrobactrum anthropi, Aeromonas?salmonicida, Micrococcus lylae, Corynebacterium ulcerans, Pseudoalteromonas spp, Vibrio fluvialis. Attained from the experiment of copper biosorption, A.?salmonicida had a maximal biosorption capacity among them, and Vibrio minimal. Based on this trail, A.salmonicida, C. ulcerans and Vibrio were selected for next trails included optimal biosorption time, optimal pH value and effect of pre-disposal by several chemical reagents on biosorption capacity. The results showed: optimal biosorption time was between 40 minutes and 60 minutes, and optical pH value 4~5. Pre-disposal by HCl leaded to lost the absorption capacity of A.?salmonicida, but was opposite by NaOH and ethanol. For C. ulcerans and Vibrio, the copper absorption capacities were increased by them.

Abstract:The isolation of the endophytic bacteria from mangroves and screen of the antagonistic bacteria against the Phytophthora capsici were studied in this paper. The results showed that there were a large number of the endophytic bacteria in the tissues of mangroves. Of the endophytic bacteria, about 27.97% strains expressed the inhibitive activities to P. capsic. Using the eighteen antagonistic bacteria to control pepper fruit Phytophthora blight showed that all the tested strains had some control efficacy to the disease. In them, strain RS261 isolated from the leaf of Rhizophora stylosa was found to have the best control efficacy. Based on the morphological, physiological and biochemical characteristics and on 16SrDNA sequences analysis, strain RS261 was identified as Bacillus amyloliquefaciens.

Abstract:To get high cell density, pH-stat fermentations of L. casei Zhang were carried out in the medium optimized previously under different cultural conditions. The influences of neutralizing agents, the concentration of buffer salts and glucose in the medium, pH, aeration and fed batch fermentation on the growth of L. casei Zhang were investigated. Based on the values of maximum specific growth rate, biomass and viable cells count in different cultural conditions, the optimal growth condition was regarded as follows: Glucose level of the medium was 80 g/L ~100 g/L; The pH was kept constant at 5.9 with aqua ammonia and anaerobic condition was kept by sparged with nitrogen periodically; The temperature was set at 37°C and cultured for 10 h ~12 h. The biomass and viable cells' number of L. casei Zhang under this culture conditions were 7 g/L and 3.5×1010 CFU/mL respectively, and were 7 times as high as that before optimized, which can meet the requirements of probiotics.

Abstract:The effects of Spirulina on intestinal microflora of diarrhea model mice were observed. Diarrhea model mice were geted by gastric perfusion ampicillin, then these mice were given different doses spirulina by gavage. Selective culture media were used to culture bifidobacteria, bacterium lacticum, enteric bacilli, enterococci, bacteroid, clostridium perfringens in feces at different times. In order to find the difference of collecting samples from feces and intestine, the quantity of detection flora in different segment of intestine were compared too. The result showed that in middle dose group and high dose group spirulina can regulate and improve intestinal flora of diarrhea model mice, and effectively shorten time from disturbance to balance. Fecal sample and intestinal contents sample both manifest a same trend, that is the quantity of bifidobacteria, bacterium lacticum in treatment recovery group is significantly higher than saline group, and enteric bacilli, enterococci, bacteroid, clostridium perfringens is significantly lower than saline group, but each index flora in intestinal contents sample has a significant difference in quantity.

Abstract:A strain of Mucor named M2, which could produce protease, was isolated from a traditional fermented soybean product. Culture conditions of proteases produced by M2 were studied therefore. The results showed that nitrogen source and carbon source preferred for protease production were soybean protein isolate and glucose, while inorganic salts preferred were KH2PO4, CaCl2 and MgCl2. The suitable culture conditions for protease production were as follows: culture temperature was 28°C, inoculation volume was 2%, liquid level was 100 mL in 300 mL triangle bottle at pH 5, rotating speed was 150 r/min and culture time was 48 h. The obtained protease activity in culture was about 4.35 U/mL. The protease produced by Mucor was analyzed with SDS-PAGE. The protease had a molecular weight of 36.4 kD.

Abstract:It is used the method of pure culture, Selected 32 strains, which were obvious difference in the shape, color and so on common characteristic, From the chilled beef with no packing and cling film on sale in this research; and it was included 12 strains from the chilled beef sample packed with cling film; 20 strains from the chilled beef sample with no packing. Simultaneously selected 4 strains which were predominant in each bacterium from the two samples to conduct the further research, 8 strains serial numbers are: S01~S08, S01~S04 from the chilled beef sample with no packing; S05~S08 from the chilled beef sample packed with cling film. Through ARDRA (Amplified ribosomal DNA restriction analysis) as well as 16S rDNA to clarify the bacterium's classified status. The physiological and chemical tests were done to determine the various bacteria respective genus. The experiment indicated: S01 is Pseudomonas putida; S02 is Shewanella cincia stain; S03 and S05 are the same Shewanella putrefaciens; S04 is Stenotrophomonas maltophilia; S06 is Psychrobacter; S07 is Staphylococcus sciuri; S08 is Microbacterium- laevaniformans. It was proved that two samples altogether have the same predominant bacterium. It can provide certain theory basis for the chilled meat processing craft as the preliminary investigation in the cultured microorganism situation in two samples.

Abstract:In this study, a mutant designated NC1150 which dose not produce streptolysin was selected from wild-type Streptococcus equisimilis by ultraviolet ray combined with 60Co-γ ray mutation. Through further 60Co-γ ray mutation a high-producing hyaluronic acid mutant designated NC168 was obtained. This selected mutant NC168 could produce hyluronic acid 1.01 times as much as the original strain NC1150 and relative molecular weight of hyaluronic acid touched 0.55×106 D. Furthermore, its hyaluronic acid output and relative molecular weight of hyaluronic acid maintained genetic stability after 10 generations and there was no reverse mutation on hemolysis.

Abstract:The purpose of this investigation is to improve ethanol production and decrease acetate formation in Saccharomyces cerevisiae strain YS2-Dadh2. The strain YS2-Dadh2 with deleted alcohol dehydrogenase Ⅱ(adh2) gene was isolated in our lab with higher ethanol production than that of the strain YS2. The acetaldehyde dehydrogenase Ⅵ (ald6) gene encoded a cytosolic acetaldehyde dehydrogenase, a key enzyme of the pyruvate dehydrogenase (PDH) bypass, transfers acetaldehyde to acetate. To disrupt ald6 gene of the strain YS2-Dadh2, ald6 gene targeting cassettes were synthesized by long flanking homology PCR (LFH-PCR) and then were transformed into YS2-Dadh2 mutants by LiAc/SS Carrier DNA/PEG method. Positive transformants were selected with G418 and further confirmed by PCR. Once correctly integrated into the genome, the selective marker was rescued by transforming the plasmid pSH65 into the positive transformants and inducing the Cre expression with a Cre/loxP-mediated marker removal procedure. We named the ald6 gene knocked-out strain as YS2-Dadh2-Dald6 which has a 12.5% higher ethanol production and a 18% lower acetate formation compared to the strain YS2.

Abstract:The strain Streptomyces sp., nominated IMB-14, was isolated from the soil sample of WuDang Mountain by the method of cellulose ester membrane filter. The studies on antibiotic activities, morphological characteristics, cultural characteristics, physiological characteristics, 16S rDNA sequence analysis and the metabolite of strain IMB-14 showed that the strain IMB-14 was accordance with Streptomyces xanthocidicus. The study on the isolation and identification of strain Streptomyces xanthocidicus establishes a foundation on screening of novel antibacterial and antitumor agents.

Abstract:A strain of high-biomass, producing glucose tolerance factor yeast strain was screened from seven yeast strains and seven strains mutated by spaceflight-induced mutagenesis through gradient concentration of chromium plates cultivation and liquid fermentation cultivation. The biomass of it was 40 g/L. Extracting GTF with ammonia and determining the content of Cr with flame atomic absorption spectrometry, the content of organic Cr was 1287 mg/g and that of total Cr was 1917 mg/g. At the same time, dynamic relationship between other parameters and the amount of organic chromium was analyzed during fermentation.

Abstract:Monascus spp., a kind of filamentous fungi, produce abundant of important metabolites which were widely used in the fields of food and medicine. Until now, there are few reports on the important functional genes of the Monascus spp. due to little genetic information. In this paper, the feasibility of gene deletion mediated via Agrobacterium tumefaciens on the basis of homologous recombination was analyzed by studying on the deletion of the RGS domain of putative G-protein signaling regulator gene mrfA in Monascus ruber. The length of homologous arms of deletion vector pC805S were 958 bp and 824 bp, respectively. There were 26 transformants in which homologous recombination occurred in 138 transformants and the recombination rate was 18.8%. The result showed it was feasible to identify the function of unknown gene in M. ruber with the targeted-deletion technology mediated via A. tumefaciens.

Abstract:Based on the principle of homologous recombination, we construct gene knock-out mutant of neuB gene encoding sialic acid synthase in Streptococcus suis serotype 2 (SS2) virulent strain 05ZYH33. PCR analysis and Southern hybridization confirmed that the coding gene of neuB was replaced completely by spcr cassette in one mutant, the mutant of 05ZYH33 neuB gene was successfully constructed. Analysis of biological characteristics showed that there were no differences in mycelial morphology, hemolytic activity and dyeing properties between the mutant and 05ZYH33; but the capsule of mutant was thinner and more compacted than that of the wild type strain 05ZYH33. Virulence assays with murine model confirmed that the mutant is avirulent. These observations indicate that sialic acid plays an important role in the pathogenesis and invasiveness of SS2.

Abstract:Proteomics is an emerging discipline developed on the basis of genomics. The fundamental techniques of proteomics include sample preparation, protein separation, protein identification and analysis, and its core techniques are two-dimensional gel electrophoresis and mass spectrometry. In recent years, proteomics has been used in researching the field of Mycobacterium tuberculosis (MTB). Proteomics promotes deep understanding of the pathogenesis of MTB and resistance mechanism via isolating, identifying and analyzing the whole-cell protein and secreted proteins. The development of new vaccine against MTB has showed some promising results based on proteomics. Some powerful early diagnostic markers have been discovered via analyzing the protein composition of MTB clinical isolates. Proteomics also applies to find potential new drug targets, and it has shown many valuable research productions in developing new anti-MTB drugs. In summary, the application of proteomics has built a solid foundation for the development of prevention, early diagnosis and treatment of tuberculosis.

Abstract:Bacteriophage is a kind of virus depending on bacterium, named bacterial virus, and it can multiply in bacterium. There’re six types of Chlamydiophage discovered which are Chp1, Chp2, Chp3, Chp4, CPAR39 and PhiCPG1. Capsid proteins Vp1, Vp2 and Vp3 are three major structural proteins of Chlamydiophage. The study of Chlamydiophage will play great action on chlamydia infection therapy.

Abstract:Heterotrophic nitrification bacteria are able to utilize organic carbon sources to grow and produce hydroxylamine, nitrite and nitrate from nitrogen compounds, and most of them can also denitrify these products to gaseous nitrogen compounds simultaneously. Therefore, more and more attentions are paid to heterotrophic nitrification bacteria for wastewater treatment. This paper reviews the denitrification characteristics of some isolated heterotrophic nitrification bacteria, and analyzes the influence of various conditions to the heterotrophic nitrification bacteria, such as temperature, pH, DO, carbon sources, C/N, and inhibitors, etc. At last, the present situation and potential applications of wastewater treatment by heterotrophic nitrification bacteria are introduced.

Abstract:Phage display is a widely used gene engineering high technology. Through the display of exogenous peptides or proteins fused specific coat protein on the surface of phages, it is possible to construct proteins or peptides libraries and screen interesting proteins, peptides and antibodies successfully. Most commonly used phage display technology is phagemid/helper phage system, in which helper phages are essential for the replication and assembly of phagemid particles. In this review, in combination with the newest research dynamic status, we summarize phagemid/helper phage double-genome system. We mainly emphasized the features and mutation mechanisms of different helper phages. We also made some prospects for the future directions, in the meanwhile, we also expect that our experience can provide some help for further maturity of the technology.

Abstract:At present, the enhanced biological phosphorus removal (EBPR) process has been widely used for its cost-effctive, but a type of bacteria-glycogen accumulating organisms(GAOs) which can compete with phosphate accumulating organisms (PAOs) and lead to the deterioration of EBPR. There have been many studies about PAOs-GAOs, the conclusions have both convergences and contradictions however, so it is necessary to discuss and analysis. According to the relevant reports at home and abroad in recent years, the factors affecting the enrichment culture of PAOs and GAOs are expounded, including P/C ratio, carbon type, temperature, pH value which are more important in the system. In addition, sludge age, dissolved oxygen, etc. also played a role for the competition of PAOs and GAOs. In EBPR system, denitrifying phosphate accumulating organisms and denitrifying glycogen accumulating organisms which also have impact on the enrichment of PAOs and dephosphorization were observed in anoxic condition. Finally, the future direction of the EBPR system for the future is viewed.

Abstract:Based on improving experimental operating skills of students and considering the features of microbiology experimental technology and methods, we developed a new examination ways of microbiology experiment — “multimedia papers of microbiology experiments” to use among 2005 and 2006 students of sophomore(entering campus in 2005 and 2006) of biotechnology and bio-science for microbiology experiment examination. Analysis of the results of experiment examination and theoretical examination for the 2005 and 2006 students showed that the disharmony and miscorrelation between experiment examination results and theoretical examination results were overcome, and students got more interested in experimental classes, while their experimental operation is more conscious and accurate.

Abstract:Some new attempts for the comprehensive experiments of microbiology experiment course were discussed, which would be helpful to the improvement of teaching effects of comprehensive experiments. They were summarized four “integration”, as follows: foundation and profession, innovation and systematization, maneuverability and scientificity, and participation of teachers and students.

Abstract:A rapid, sensitive and specific method of DNA microarray combined with multiplex PCR that allow the simultaneous detection and identification of Shigella dysenteriae, Salmonella spp. and E. coli O157. The invasion-associated plasmid antigen H of S. dysenteriae(ipaH), Salmonella spp. enterotoxin gene(stn) and Escherichia coli O157 Shiga-Toxin gene(slt) were used as target genes, and then three pairs of primers and captured oligonucleotide probes were designed and synthesized. The multiplex PCR products were hybridized with DNA microarray, which contained specific probes of three foodborne pathogenic microorganisms. Genomic DNAs from 26 bacterial strains were detected, and only 3 index bacteria were positive. The detection limit of this assay was around 8 pg genomic DNA. In addition, this method was applied to detect artificially contaminated food samples, and the detection limit was 50 CFU/mL for non-cultured samples. These results suggested that detection of pathogenic microorganisms by DNA microarray is an effective procedure with high specificity and sensitivity. The DNA microarray assay developed in this study could provide an informative supplement to conventional microbiological methods for routine monitoring of food.

Abstract:The real time PCR method based on TaqMan fluorescent DNA probe that specific for Mycobacterium paratuberculosis detection was established and developed into testing kit for rapid clinical diagnosis. The kit provided reagents for real time PCR and DNA extraction. The whole detection procedure included sample treatment and real time amplification could complete within 1 d. The testing kit could specifically identify 8 reference strains of M. paratuberculosis among various environmental existing microorganisms and 12 strains of other mycobacteria including M. tuberculosis, M. bovis and M. avium. Tests on M. paratuberculosis culture samples and serial ten fold dilution of recombinant plasmid containing target template showed that, the assay could detect single bacterium and 15 copies of target gene, which was 100 fold increase of sensitivity than the gel-based PCR using primers of the same sequences. And the test on 20 mimic infected milk sample containing 50~100 bacteria of M. paratuberculosis all yielded positive results. The inter-assay CV% and intra-assay CV% of the kit was 1.41%, 2.42% respectively. We used the testing kit to investigate infection of M. paratuberculosis on domestic and imported animals. Nature samples including 250 fecal and milk samples from 7 cattle farms, 143 serum samples from 10 pig farms within Guangdong province, and 100 serum samples from three shipments of imported monkey, were collected and tested. The positive rate of M. paratuberculosis was 7.7% in cattle serum, 3.7% in cattle fecal, 8.2% in pig serum and 3.0% in monkey serum respectively.