Abstract:

Abstract:Reverse transcriptase-PCR experiments suggest that the two clusters of genes potentially involved in the oxidation of reduced sulfur compounds are organized as operons in strain of the acidophilic, chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans ATCC 23270, the two clusters of genes including such the ORF of putative sulfate-thiosulfate-molybdate binding proteins, the ORF of putative thiosulfate: quinone oxidoreductase and the ORF of the rhodanese-like protein (P21). Bioinformatic analyses have predicted the possible promoters sequences and the possible +1 start site of transcription for the doxDA operons.

Abstract:The nitrite-reducing activity of aerobic denitrifying bacterial strain N6-1 was studied. It showed that the nitrite-reducing activity reached the highest at 30℃, 120 r/min, pH 8.5 and C/N ratio 12, using CH3COONa and NaNO2 as the sole carbon source and nitrogen source, respectively. When the initial NaNO2 concentration was 2 g/L, NO2--N was reduced completely after 20 hours cultivation with the reducing rate of 20.3 mg/L·h. There would be no effect on its nitrite-reducing activity in the present of 1.5% NaCl or 1% peptone. The cell concentration could reach 1.2×1011 CFU/mL after 24 hours cultivation in 10 L fermentor.

Abstract:A bacterial strain, which utilizied Benzo[a]pyrene (B[a]P) as the sole carbon and energy source for growth, was isolated from soil heavily contaminated by PAHs. This strain was identified as Paracoccus sp. by its morphology and 16S rDNA sequence, and designated HPD-2. After incubated in MS medium containing B[a]P of 3.0 mg/L for 5 days, 89.7% of B[a]P was degraded by HPD-2. When this strain was grown in pyrene and fluoranthene of 50 mg/L for 7 days, 47.2％and 84.5% of which was degraded respectively. Thus, this study provides evidence for the potential application of HPD-2 for improving HMW- PAHs biodegradation.

Abstract:The ldhL-encoding gene was amplified from Rhizopus oryzae genome DNA using PCR technique, and the PCR product was approximately 1000 bp DNA segment. The PCR products were cloned into pMD18-T vector and identified by enzyme cutting analysis. The sequence results showed that ldhL gene is 963 bp. The DNA fragment of ldhL was subcloned into prokaryotic expression vector pET30a and the specific fusion protein with molecular weight 43 kD was expressed, the result showed that the cloned ldhL was expressed in BL21. The levels of ldhL activity expressed by E. coil BL21/ pET30a-ldhL were up to 98 U/mL. The results are expected to lay foundation for further studies on the gene engineering Rhizopus oryzae strain of high yield L(+)-lactic acid by fermentation of whey.

Abstract:A strain of Cellulosimicrobium cellulans Ha8 was studied on its morphological, biological characteristics and its utilization of several kinds of benzoic compounds, the results showed this strain was Gram-positive, the long rod-shaped cells were changed into short rod-shape gradually. pH value from pH 6.0 to pH 9.0 and the temperature from 20℃ to 40℃ were good for its growth. It could not only hydrolyze protein and starch, use cellulose and pectin, decomposite chitin, liquify gelatin and fix nitrogen, but also use phenol, xylene, benzoic, cinnamic acids and diphenlamine as the sole carbon resource for its growth. It could tolerate 0 mmol/L~30 mmol/L, 0 mmol/L~8 mmol/L, 0 mmol/L~30 mmol/L, 0 mmol/L~15 mmol/L and 0 mmol/L ~ 40 mmol/L of benzoic acids, phenol, xylene, cinnamic acids and diphenlamine seperately, but could not use 2,4-dinitrophenol, o-Nitrophenol, 2-Methoxyphenol, aminobenzenesulfonic acid, catechol and o-Phenanthroline as its sole carbon resource.

Abstract:In the experiment, 68 endophytic bacteria strains of maize were isolated and purified from seedlings of three maize cultivars (Chuandan13, Chuandan418 and Chuandan416). Subsequently, these bacteria were identified and studied. The results indicated that these bacteria belong to five different genera. Among them, Bacillus, Micrococcus was the most widely distributed and predominant. Bacilli were classified into 5 species level. The endophytic bacteria isolated from three maize cultivars were variable, and the number of different species population of these endophytic bacteria followed as chuandan13>chuandan418>chuan- dan416. According to the inhibitory spectrum and influence of endophytic bacteria fermentation to the corn seeds, two strains (BH and B98) had wide pathogen range and didn’t inhibit the viability of the seeds under intraventricular condition; the pot experiment results indicated both of the two strains could promote maize growth and antagonize the Rhizoctonia solani.

Abstract:In this paper, the number of rhizosphere and non-rhizosphere microbial organisms of fusarium wilt resistant and susceptible watermelon under soil culture and soilless substrate culture were was studied by traditional culture methods. The results showed that, the number of rhizoshpere microbial organisms is was significantly higher than non-rhizosphere, and the number is was changed with the stage of watermelon grow, the number is was the lowest in seedling stage and increased with the watermelon grow, and achieved highest at the flowering and fruiting stage, decreased with the watermelon ageing. The fusarium wilt resistant of watermelon is was correspondence with number of rhizosphere bacteria; the number of rhizosphere bacteria of resistant watermelon is was higher than that of susceptible watermelon in each stage under soil culture and soilless culture. The fusarium wilt resistant of watermelon is no correspondence with number of rhizosphere fungi and actinomycete. The number of non-rhizosphere microbial organisms is was changed in a small range in the whole growing stage. The non-rhizosphere bacteria have no significant change in the whole stage under soil culture and increased quickly under soilless substrate culture and decreased at the later stage. The non-rhizosphere fungi and actinomycete reached highest at the later stage under soil culture or soilless substrate culture.

Abstract:Pasteuria spp. was one of the highly potential biocontrol agents of plant-parasitic nematodes. Based on their 16S rDNA sequences, we developed simple PCR, PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) and PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) methods for rapid detecting the genetic diversities of Pasteuria spp. in root samples. Using simple PCR, we detected Pasteuria spp. from nine out of thirty nematode-infected samples collected from different crops in Fujian and Guangzhou of China. The genetic diversities of Pasteuria spp. in root samples were examined by PCR-RFLP and PCR-SSCP. Two of the five variant RFLP patterns were predominant among the clones when they were digested by restriction enzyme EcoHI. The results from PCR-SSCP analysis were consistent with those of PCR-RFLP and showed greater gene diversities. Twelve clones were chosen and sequenced. The results indicated the sequences of clones shared 97.8%~99.7% similar identity with those of previously reported P. penetrans, and the clones were further divided into one major clades and seven individual clades in the phylogenetic tree.

Abstract:The fermenting liquor from Aspergillus niger D2-26 was purified to obtain a single protein component, and then the characterization of thermostable lactase was studied. The enzyme had an optimum temperature of activity at 70℃ and an optimum pH of 2.5, and had good temperature tolerance from 30℃ to 60℃ and the pH stability at 2.0~9.0. Mn2+ had a significant activation on lactase activity, whereas the enzyme activity was inhibited strongly by Hg2+、Pb2+ and SDS; the Vmax, Km, molecular mass of single subunit protein and glycosylation of Lactase was 0.097 nmol/min, 8.77 mmol/L, 116.978 kD and 11.3%, respectively.

Abstract:The isolate GN52 of Riemerrella anatipestifer was passaged on the Martin Medium successively according to the optimum condition. The experiments included Gram staining, biochemical test, drug sensitivity test and animal experiments were carried out on the bacteria of 3rd, 11th, 21st, 31st, 41st, 51st and 61st generations. It indicated that the bacterial morphs, biochemical character, drug resistance of the strain had no obvious change, but the virulence showed a trend of reduction.

Abstract:A novel recombinant Escherichia coli BL21(DE3)/pET-ChIFN-γ was successfully constructed for high expression of chicken interferon-γ(ChIFN-γ), and the heredity stability of pET-ChIFN-γ was mainly focused on. It was segregationally unstable of the plasmid under no kanamycin selection pressure, only 69% cells containing plasmid after 100 generations. But it could be controlled by the supplementation of kanamy- cin pressure. The growth characteristics and the morphology of the cultures did not show differences among the generations. The chromatogram of the plasmids between origin strain and 100th generation strain di- gested by restriction enzymes were same, as well as ChIFN-γ expression level, biological activities showed no difference among the generations. It is indicated that recombinant strain CH1 has high heredity stability.

Abstract:Pathogens cultivation and histopathological observation was made on Fugu obscurus with the symptom of ulceration. Microscope examination on ulcers and muscle tissues which infected with fungal mycelium that was coarse, without branch, Gram staining positive. Heart, liver, spleen and intestine contained small amount of inflammatory cell invasion without fungal mycelium and obvious pathological changes. The result of Sabouraud medium culture with the temperature of 37℃ as follow: Mycelia had pale yellow spherical sporangium after 24 h; mycelium appeared, the sporangium matured and oval spores released after 72 h; glass utensil was full of colony after 120 h. Pathological examination of subcutaneous ulcer and muscle revealed that a large number mycelia and inflammatory cell invaded subcutaneous tissue, which caused neighboring muscle tissue degeneration, necrosis and interstitial edema; Coarse hyphae penetrated mucosal into the basement with the result of small vascular embolization at the same time. Mycelium contained blue color and branch looked like a right angle. According to Ainsworth classification system, the pathogen was identified as Mucor sp.

Abstract:A 954 bp fragment corresponded to the main antigen determinant domain of apxIA gene of Actinobacillus pleuropneumoniae(APP)was amplified by polymerase chain reaction (PCR), from serovar I reference strain 259 and was ligated to pMD-18T vector for sequencing. After confirming the sequence correct, the extracted plasmid DNA was digested with EcoR I and Not I, followed by subsequent ligation into the prokaryotic expression vector, pGEX-4T-1, to construct an expression plasmid pGEX-4T-1/apxIA. The recombinant expression vector was transformed into E. coli DH5α for expression under the induction of 0.4 mmol/L IPTG. Glutathione Sepharose 4B was used for a further purification after the GST-fusion protein denatured and refolded by Urea. SDS-PAGE analysis revealed that the recombinant pGEX-4T-1/apxIA could be able to express efficiently in a form of inclusion body with 32% accumulated total amount of bacterial protein and the purity quotient of the GST-fusion protein was up to 95%. It is suitable for the clinical diagnosis and subunit vaccine of actinobacillus pleuropneumoniae infection.

Abstract:In this study, two special primer pair containing EcoR V and Xho I according to complete genome of duck hepatitis virus 1 (DHV1) were designed to amplify VP1 and 3D genes from cDNA of DHV1. The target genes VP1 and 3D were subcloned into PET32a vector digested by EcoR V and Xho I respectively. Then the recombinant plasmids were transfected into Escherichia coli BL21(DE3) for VP1and 3D expression. The bacteria containing PET32a-VP1 and PET32a-3D were collected and examined by SDS-PAGE and western-blotting. Result showed that the VP1 and 3Dprotein were expressed in E. coli and the amount of expression was higher. Molecular weight of the protein was 48 kD, 68 kD. The protein can be recognized by DHV1antibody. This study showed that the protein VP1 and 3D have antigenicity.

Abstract:The adhesion of 9 pig Lactobacillus strains on IPEC-J2 cell line and the effect of 5 Lactobacillus strains on the competitive, exclusive, displacement of adhesion and invasion of Salmonella typhimurium DT104 to IPEC-J2 cells were investigated. The 9 pig Lactobacillus strains exhibited dose- and strain-dependent adherence to intestinal epithelial cells by 0.1%~10%. The ability to inhibit the competitive adhesion of Salmonella typhimurium DT104 appeared to depend on the dose and Lactobacilli tested. Salmonella typhimurium adhesion was reduced above 80% by 109 CFU/mL K30, K67 and K16 strains. Adhesion percent of S. typhimurium DT104 was reduced 40%~70% by pre-treating the cells with 109 CFU/mL Lactobacillus prior to adhesion to IPEC-J2 monolayers, while invasion percent was reduced 23%~33% by 108 CFU/mL Lactobacillus. However, no inhibition of displacement was detected at low concentration of Lactobacillus, while 12%~84% displacement was detected with high concentration. Therefore, the observed inhibition of S. typhimurium adhesion and invasion to IPEC-J2 monolayers with Lactobacillus could be efficient for preventive or curative probiotic therapy in pigs with S. typhimurium disease.

Abstract:Norovirus (NV) was one of new borne viruses, which was found firstly in the USA in 1972 and not reported in China until 1995. The main food-borne viral pathogens affect people badly and cause the epidemic acute gastroenteritis in all age groups worldwide. In this study, the genomic RNA was extracted from the non-bacterial gastroenteritis samples. A 1623 bp fragment, containing the complete coding sequence of the ORF2 gene, was amplified from the NV samples by RT-PCR. Sequencing analysis showed that it belongs to GII and shared more than 99% homology with the corresponding sequences published in the GenBank(DQ419908 and DQ369797). The ORF2 gene was then in-frame fused to the prokaryotic expression vector pET-28a, and the resultant recombinant plasmid was transformed into Escherichia coli BL21 (DE3) competent cells. A 62 kD fusion protein, named rVP1, was expressed after IPTG induction. Rabbits were immunized by the purified rVP1. Western Blot results showed that the high titer antibody can specifically recognize the VP1 in the clinical samples from hospital. The data suggested that the rVP1 has good immunogenicity and reactiongenicity. The minor protein in the expression product was analyzed by Western Blot and double?immunodiffusion?test. The data showed that the minor proteins were the fragments of rVP1.

Abstract:Microbial is a renewable resource which can produce polysaccharide. Its unique physiological activities and broad applications are attracting increasing attention. In this article, the source and the fermentation conditions of microbial polysaccharide was reviewed, with a view to provide a scientific basis for the production of the microbial polysaccharide.

Abstract:Bacillus thuringiensis is one of the most effective and the most widely used microbial insecticides at present. The approaches to the strategy for high performance insecticide such as selective preference strain, constructive genetic engineering bacteria, mutagenesis screening and directed evolution are reviewed in this paper. Moreover, the advancement and the application prospects in high performance insecticide are discussed.

Abstract:Natural big molecular substances mainly include protein, nucleic acid and sugars. In this paper, the anti-TMV recent research, application and action mechanism of these big molecular substances from high plants, zoos and microorganisms were reviewed. Antiviral action mechanism of these natural substances had multiple aspects and available results indicated that inhibitory and interference activity of virus multiplication and induced resistance activity.

Abstract:Dimorphism is the capacity displayed by different fungi to grow in the form of yeast or mycelium, depending on the environmental conditions. It has long been believed that phase transition between yeast and mycelium is obligatory for pathogenicity in some dimorphic fungi, so dimorphism of fungi attracts a great deal of attention in recent years. Dimorphic transition is regulated by a variety of extracellular factors including physical factors, chemical factors and nutritional factors, and it is also regulated by intracellular signal transduction pathways such as cAMP-PKA, MAPK and Rim101. This review focuses on recent research progress on environmental factors and signal transduction pathways that affect dimorphism in fungi.

Abstract:Cytochrome P450 are abundant in Streptomyces which play an important role in the biosynthesis of secondary products and metabolism of exotic chemicals of Streptomyces. Recent progress and function of cytochrome P450 in Streptomyces were reviewed in this paper. The problems in study of Streptomyces Cytochrome P450, and the prospects for future study of cytochrome P450 and its application were also discussed.

Abstract:Carbon-nitrogen lyases (E.C.4.3) are a group of enzymes that release ammonia, amidine or amino group etc,?and also show ability to form double bond or ring structure. Specifically, enzymes forming amino group are called amine-lyases (E.C.4.3.3), which are critical in the industrial production of many medicine intermediates. In this review is a summary of four major amine-lyases in terms of their source, enzymatic characteristics and their applications in preparation of pharmaceutical intermediates.

Abstract:There are one third of synthesized proteins must be secreted to the cell surface or to the surrounding environment to acquire their native functional state. Most of them are exported by Sec translocase (secretion pathway). Sec translocase consists of a membrane embedded protein-conducting channel, termed SecYEG and a peripherally associated motor domain, the ATPase SecA. The SecDFyajC heterotrimeric membrane protein complex can facilitates protein translocation. SecB is a molecular chaperone that functions in the protein translocation pathway. SecM (secretion monitor) encoded by the 5' region of the secM-secA mRNA, which elongation arrest is required for upregulated expression of SecA. The signal sequence in the N terminus of the nascent peptide is first recognized by the signal recognition particle (SRP). SecB, the Sec-system-specific chaperone, channels the preprotein to the Sec translocation pathway and, additionally, actively targets the bound precursor to the translocase by its ability to bind SecA. The preprotein-bearing SecA then binds to the membrane, at a high-affinity SecA-binding site, SecYEG, which constitutes a channel for polypeptide movement. Continued translocation requires cycles of ATP hydrolysis by SecA, which is thought to occur in a step-wise fashion with a step of 20~30 amino acid residues.

Abstract:Microorganisms in plant habitats of intertidal zone are oceanic populations that enriched in biodiversity and medicinal value. Characteristics and prospect of the microorganisms and their special habitats were introduced in this review, which provide reference for the development and utilization of microorganisms in these regions.

Abstract:Heavy metal treatment in wastewater by biosorption using moulds was introduced. Different uptake capacities of several different moulds were reviewed. Some factors affecting biosorption were summarized. The mechanism of moulds adsorption and techniques of immobilization were also discussed. In addition, the development tendency of heavy metal treatment in wastewater by biosorption using moulds was envisioned.

Abstract:Nitrite reductases (NiRs) are the key enzymes in the denitrification pathway of the nitrogen cycle. By the catalysis of NiRs, the nitrites are turned into nitric oxides and the nitrogen pollution is decreased in water body. NiRs are divided into two different types based on their prosthetic groups, namely heme-containing nitrite reductases (cd1-NiRs) and Copper-containing nitrite reductases (Cu-NiRs). As all know, Cu-NiRs have trimeric structures, in their each monomer, there exist two types of Cu centers that play pivotal roles as the components of electron transfer pathway in the process of catalysis. Furthermore, some residues alteration of Cu-NiRs would contribute to the catalytic reaction. In this review, the latest progresses about the construction features, the process of electron transfer and catalytic mechanism of Cu-NiRs were discussed.

Abstract:MicroRNAs (miRNAs) are recently discovered major regulators of gene expression, which play a pivotal role in a wide spectrum of biological processes including antiviral defence. There is growing evidence that some viruses either encode their own viral miRNAs or subvert cellular miRNAs. The host- and virus-encoded miRNAs and their targets together thus form a novel regulatory layer of interactions between the host and the virus. A better understanding of host-virus interaction mediated by miRNAs would not only enable us to unravel the molecular basis of viral pathogenesis, but also enable us to develop better therapeutic strategies.

Abstract:Ureases are nickel-containing enzymes that catalyze the hydrolysis of urea to carbon dioxide and ammonia. This brief review discusses the biochemistry and molecular biology of bacterial ureases and outlines its activation, regulation and biological effects.

Abstract:Gene engineering is the main course of biological engineering. It should be adapted to the demand of innovation spirit, practice ability and comprehensive quality of students. Educational reform of gene engineering conducted by constructing system of theory and practice, optimizing course teaching content, strengthening practice teaching content, using modern teaching technology, strengthening web course construction and improving teaching methods. We pay attention to impart specialty knowledge and learning methods to students. Its aim was to increase teaching effects and meet the demands of bioengineering specialty and qualified personal training in 21 century.

Abstract:Laboratory teaching played the crucial part of microbiology teaching, which was benefit to improve the operational capacity, analysis and resolving ability of students. We carried out the multiplicity teaching by remodeling experiment process, designing integral test, and resolving practical issue and setting up comprehensive trail. It was proved by fact that the multiplicity teaching increased the study interesting of students, inspired their activity, initiative and creativity.

Abstract:According to the predacity of the nematode-trapping fungi and the growth habit of pine wood nematode Bursaphelenchus xylophilus, this paper tested the B. xylophilus that cultured by the fixed time and quantities. Trying to find out the quantificational test method of trapping rate, by the change of the quantities of B. xylophilus. Three new methods of testing trapping rate were obtained successfully basing on the improvement of Baermann funnel method. Each method had advantage and disadvantage, Filter membrane and Double layer microscopic examination method were more precise, and bar-cutting microscopic examination and Baermann funnel method were more imprecise. Therefore, according to the emphasis point of experiment and precision degree of the test, the more suitable method for the test of trapping rate could be chosen.

Abstract:Single-Strand Conformation Polymorphism(SSCP) is an effect method for investigating environ-ment microbial genetic polymorphism, with its characterization of rapidness, simplicity, and sensitivity. However, many factors can influence the results of SSCP in the analysis of complex environment samples, and its optimization is highly needed. In this paper, optimal PCR-SSCP conditions were discussed based on PAGE concentration, formamide deionized in denaturing loading buffer, electrophoresis time and tempera-ture. The resluts showed that the optimal conditions were as follows: 16S rDNA V1~V3 was selected as the targeted gene, the ratio of acrylamide to N, N-dimethylacrylamide in 12% polyacrylamide gel electrophore-sis(PAGE)gel was 49:1, the ratio of formamide deionized in denaturing loading buffer was 1:3, running the SSCP gel at 300 V for 18 h (under 4℃). Aside from this, the validations using samples from a simultaneous desulfurification and denitrification bioreactor were conducted under this optimal conditions.