Abstract:

Abstract:Candida glycerinogenes WL2002-5 is an osmotolerant yeast used for the commercial production of glycerol. TRP1 gene of Candida glycerinogenes (CgTRP1), encoding phosphoribosyl anthranilate isomerase(PRA1) was cloned by complementation of the trp1 mutation of Saccharomyces cerevisiae W303-1A. Sequence analysis revealed the presence of a 735 bp open reading frame(ORF) encoding 244 amino acids protein, which shares 32.9 %~49.2% amino acids sequence similarity to PRAI proteins from other species of Saccharomycetales. Functional analysis reveal, high copy number of CgTRP1 can complement the trp1 mu-tation of S. cerevisiae completely, but low copy number of CgTRP1 can only partially complement the trp1 mutation. Downstream from CgTRP1 was found a gene highly similar to IPP1 gene which encoding inor-ganic pyrophosphatase. The nucleotides have been deposited in the GenBank database under accession No. EU078909.

Abstract:This paper focused on stausporine production by cultivation of strain H41-38. Results could be summarized as follows. The optimal condition for the shake flask cultivation for this strains was 30°C、96 h. Results indicated that the best carbon and nitrogen sources were cornstarch and yeast powder. With the method of fractional factorial design, it was found that yeast powder and crude salt were the important factors, and their optimal contents were determined. Under the optimal conditions, the calculated maximal stausporine was 252.31 μg/mL, while the experimental value of shake flask was 251.28 μg/mL. The titer was 4.33 times more than using the original culture medium. After cultivating in a 30 L fermentor (300 r/min、30°C, Vair=10 L/min~15 L/min) for 84 h, the titer was 286.44 μg/mL, which titer was 45.16 μg/mL higher than the shake flask cultivation, and curves of parameter provided useful information and data for the industrial production of stausporine.

Abstract:A thiosulfate-oxidizing bacterium TX was isolated from polysulfide wastewater treatment system. It was preliminarily identified as Halothiobacillus sp. according to its morphological, physiological properties and similarity analysis of 16S rRNA gene sequence (GenBank accession No. EU871645). This bacterium was an obligate chemolithoautotrophic sulfur-oxidizing bacterium since it could utilize thiosulfate, elemental sulfur, tetrathionate, sulfide or sulfite as sole energy source but did not show growth on the medium with glucose, sucrose, fructose, lactose, mannose or yeast extract as sole carbon source. The optimal growth condition for thiosulfate oxidation was 30°C~35°C and pH 3.0~5.0 respectively. Significant reduction in medium pH from 4.0 to 1.2 was observed due to oxidation of thiosulfate to sulfate during the batch culture incubation period. During the course of thiosulfate oxidation accumulation of tetrathionate was observed either in synthetic medium or in the mixed liquor from aeration tank of the polysulfide wastewater treatment system. This indicates that the “S4 intermediate(S4I)” pathway was responsible for thiosulfate oxidation in this bacterium.

Abstract:The mechanism of chromium accumulation and microstructure transformation of the fused yeast were studied in this paper. The result showed that the process of Cr6+ reduction and adsorption was accompanied by the H+ consumption. The main adsorptive groups on the strain surface included amino, hydroxyl, phosphate group and amide, among which phosphate group played vital role in the chromium accumulation. The removal rate of chromium and reduction rate of hexavalent chromium declined 70% and 46%, respectively, when phosphate group was masked. During the adsorption process the chromium ions complexed on the surface of fused yeast was transported into the cell wall and combined with inclusion to form steady species and this took 90 min to reach the equilibrium. The biosorption and reduction of Cr on the cell surface would alter microstructure of cell surface, reduce cell membrane potential and increase cell membrane permeability.

Abstract:Mesorhizobium huakuii strain 7653R, isolated from nodules of A. sinicus L, contains two indigenous plasmids, p7653Ra and p7653Rb, the latter being the symbiotic plasmid. We eliminated the plasmids via Tn5-sacB insertion and obtained its symbiotic plasmid-cured derivative 7653RD. Then, we transferred the symbiotic plasmid pJB5JI of Rhizobium leguminosarum bv. Viciae T83K3 into 7653R and 7653RD. The pot plant test showed an increase in competitive ability and symbiotic nitrogen fixation of transconjugant 7653R-197 (pJB5JI) compared to 7653R. pJB5JI could not restore the ability of 7653RD to nodulate Astragalus sinicus. 7653RD (pJB5JI) could form ineffective nodules on peas, implying that the symbiotic plasmid pJB5JI could express its function at the chromosomal background of Mesorhizobium huakuii 7653R. We checked the stability of plasmid in transconjugants under free-living and during symbiosis. The results indicated pJB5JI could not be detected in some nodule isolates. We amplified kan resistance gene from all transconjugants and nodule isolates which suggested that pJB5JI might fully or partially integrated into the chromosome of recipients.

Abstract:Microbial diversity of composting of agriculture organic wastes (AOW) and municipal domestic waste (MDW) in the thermophilic (T) phase was analysed by Polymerase Chain Reaction (PCR) combined with constructing of clone library. The polymerase chain reaction-amplified 16S rDNA and 18S rDNA fragments with universal eubacterial primers(27F, 1495R) and fungal primers (EF4, Fung5) were subjected to constructing of clone library, and the results of clone library indicated: there were 18 OTUs and 21 OTUs in the 16S rDNA clone library of AOW and MDW composting sample, and they belonged to 14 and 15 different genuses respectively; in the 18S rDNA clone library of AOW and MDW composting sample, there were 8 OTUs and 9 OTUs, and they belonged to 8 and 9 different genuses respectively. The doninent microbes in the T phase of composting of AOW were related to Bacillus megaterium, Rhizobium sp., Phanerochaete chrysosporium, Penicillium sp., and the doninent microorganisms in the T phase of composting of MDW were related to Bacillus megaterium, Azospirillum sp. and Phanerochaete chrysosporium.

Abstract:The skin ulceration syndrome of sea cucumber is a kind of desease induced by bacterium. In order to investigate the bacterium of infected sea cucumber and detect the N-acyl-homoserine lactones(AHLs) se-cretion of the bacterium, 7 bacterial strains were isolated from the infected sea cucumber. These strains were identified by physiological-biochemical characteristics and 16S rDNA sequence. Results show that strain C6 belongs to Tenacibaculum, strain 4 belongs to Shewanella putrefaciens group, strain TB belongs to Vibrio, strain BP2, BP3, BP4 and BP6 belong to Pseudoalteromonas, respectively. AHLs were detected with strain Agrobacterium tumefaciens KYC55. Among these bacterial strains, strain C6, 4, TB, BP3 and BP4 can se-cret AHLs, while strain BP2 and BP6 can’t. And the AHLs activity differs, from the highest to the lowest are 4, TB, BP4, BP3 and C6.

Abstract:The effect of carbon source, nitrogen source, temperature, moisture, pH and light on the fungal growth, conidia production and conidia germination of Paecilomyces cicadae LB were studied. For the fungal growth and conidia production, the optimum carbon sources were soluble starch and glucose, while the optimum nitrogen source was peptone. For the fungal growth and spore germination of P. cicadae, the opti-mum temperature was 25?C~27?C, for the conidia production, the optimum temperature was 25?C. Conidia geminated at RH 90%~100%, but did not below 90%. When RH reaches to 100% or the conidia were in wa-ter, the germination rate was the highest. The range of pH for the fungal growth, conidia production and co-nidial germination was 4~10, while the optimum pH for the fungal growth was 6 and 6~7 for the conidia production and conidial germination. The light treatment significantly influenced fungal conidia production. The lethal temperature for the fungal conidia was 55?C remaining 10 minutes. The present results suggest the isolate LB can adapt to nutrition and environment more widely, and has greater potential as biological control factor against of pest.

Abstract:A strain Actinobacillus succinogenes CGMCC 1593 was selected as the parent strain. After UV-EMS and UV-DES treatments respectively, seven mutated strains with subtle improvements in acid tolerance were obtained, and were subjected for recursive protoplast fusion. Through three rounds of genome shuffling, four shuffled strains with both higher yield and acid tolerance were obtained. The shuffled strain namely F3-21 could even survive at pH 5.2. The comparison of the shuffled strains and the parent strain for succinic acid production was also studied here. After 48 h of shake-flask fermentation, the succinic acid concentration of F3-21 was 48% higher than that of the parent strain. When F3-21 was carried out in a 5 liter stirred bioreactor with pH controlled 5.6~6.0, the accumulation of succinic acid in 48 h fermentation attained 38.1 g/L, which was increased by 45% compared with that of the parent strain (26.2 g/L). While pH was controlled at 6.5~7.0, the production of succinic acid in 32 h fermentation attained 40.7 g/L. When F3-21 was carried out in fed-batch fermentation, succinic acid concentration of 67.4 g/L was reached in 72 h fer-mentation. These results indicated that the genome shuffling could improve the acid tolerance and the suc-cinic acid production of A. succinogenes CGMCC 1593.

Abstract:The isolate XGH2321, which isolated from the rhizospheric soil of Rhizophora stylosa Griff in Dongzhaigang Mangrove Nature Reserve in China, was identified as a fungus in the genera of Penicillium based on its morphological characteristics and internal transcribed spacer(ITS) sequence analysis. After in-oculated in the modified CzapeK-DoX medium(consisted of 4% corn steep, 0.3% NaNO3, 0.05% KCl, 0.1% K2HPO4, 0.05% MgSO4, pH 7.4, 9% salinity), and cultured under the condition of 28?C in a rotary shaker at 160 r/min for 7 days, the extracts of ethyl acetate and water-soluble from the fermentation broth showed the apparent antibacterial activities against the growth of Staphylococcus aureus, Sarcina lutea, and Bacillus subtilis with the minimum inhibitory concentration (MIC) of 800 μg/mL and 400 μg/mL, respectively. While at the same time, these two extracts could also suppress the growth of the plant pathogen, Rhizoctonia solani with MIC of 400 μg/mL and 200 μg/mL, respectively.

Abstract:This paper described the results of the optimal method for preparation and extraction of lectin from Phaeoporus obliquus(Pers ex Fr).(J.Schroet). We determined the optimal buffer solution using the ag-glutination test with 2% hare blood cells. The optimal extraction process included the following parameters that were conformed by optimization analysis: material-water ratio, extraction time, concentration of sodium chloride and the pH value. The results are that the agglutination indexes of POL using TBS and PBS extrac-tion buffer were 64 and 16, respectively. The optimal extraction process is that, the material-water ratio was 1:50, the extraction time was 20 h, while the concentration of sodium chloride was 0 mol/L and pH was 8.0. The agglutinability of POL was 256 examined by this method. The optimized extraction process is stable and practicable, which may supply some basis for the application of the lectin from Phaeoporus obliquus in immunoregulation.

Abstract:272 endophytic actinomycetes were isolated from different medicinal plants collected from tropical rainforest in Xishuangbanna of Yunnan province. By antimicrobial screening, the fermentation broth of 146 strains inhibited the tested pathogenetic strains, and 94 or 127 out of the 272 endophytic actinomycetes strains showed inhibition activity against pathogenetic bacteria or fungi. The strain YIM 61470 exhibited extensive antagonism against pathogenic microbes. Based on the morphological characteristics, cultural characteristics, physiological characteristics, chemotaxonomic data and 16S rRNA gene sequence similarity analysis, strain YIM 61470 was identified as Streptomyces hydrogenans, a known species of the genus Streptomyces.

Abstract:To prokaryotic express pili-like protein(PLP) SSU2101 of the Chinese strain 05ZYH33 of Streptococcus suis serotype 2(S. suis 2), elucidate its immunogenicity and immunoprotection. The plp gene was amplified by PCR, and then cloned into prokaryotic expression plasmid pET32a. The recombinant plasmid was transformed into E. coli BL21 competent cells to express the recombinant PLP(rPLP). The rPLP protein was purified by affinity chromatography methods. Western blot indicated clearly that the rPLP shares strong specific immunogenicity. Animal infection experiments demonstrated that the rPLP protect mice from lethal challenge with S. suis 2 infection, which suggest rPLP might be a candidate component of S. suis 2 protein vaccine.

Abstract:To obtain non-pathogenic rabies virus glycoprotein (RV-G), we expressed RV-G in Saccaromyces Cerevisiae (S. cerevisiae). In our study, tat-G fusion gene was cloned into the expression vector pYes2.0, which allows expression of a foreign gene in the yeast cells under the control of GAl1 promoter. Transformation was performed by using lithium-treated yeast cells and several Ura+ -tranformants were isolated. According to the relative mobility in SDS-PAGE, we know probably two forms (designated as yGI and yGⅡ) of RV-G analogues produced in S. cerevisiae, their molecular weights were estimated as 66 kD and 56 kD, respectively. On the other hand, there was a specific band about 56 kD shown in western blot result. Com-bining precursors’ achievements, we will draw a conclusion that trans-membrane domain (TD) and cyto-plasmic domain have a negative regulation on RV-G antigen immunogenicity in S. cerevisiae.

Abstract:A new wood-degrading fungus Monodictys asperospera (Cooke & Massee) Ellis with a high level of laccase production was chosen to study. This laccase was purified by ammonium sulfate precipitation, DEAE-cellulose and sephacryl S-300. Purification of about 8.1 fold was achieved with an overall yield of 5.7%. Its molecular weight was estimated to be about 77 kD. The optimum temperature and pH of the laccase activity were 55°C and 6.0, respectively. Kinetic studies of the laccase showed that the Km and the Vmax for using syringaldazine as substrate was 0.163 mmol/L and 0.194 mmol/(L·min), respectively. The carbohydrate content was 18.14%. In addition, it was found that laccase activity was significantly inhibited by Cu2+.

Abstract:RNAs isolated from the foot-and-mouth disease virus strain AF72 were used as templates for RT-PCR to amplify the target gene. The PCR products purified were cloned into the pGEM-T easy vectors and transformed into E. coli JM109. The positive recombinant plasmids were identified by electrophoresis, PCR, and restriction digestions with Spe I and Spe I analysis. The nucleotide sequences were confirmed by comparing with the full-length sequence of the other reference strains. The 3D model of structure protein VP3 of FMDV strain AF72 was obtained using homology modeling. On the basis of several parameters, such as hydrophilicity, flexibility, antigenic index, and surface probability, the B cell epitopes on VP3 were predicted. After analyzing the difference among VP1, VP2, VP3, VP4, at the nucleotide level, the mutation rates of these four encoding sequences were no difference (P > 0.05), however, at the amino acid level, those mutation rates were different (P < 0.05). The regions of 1th~24th、24th~35th、36th~42th、45th~56th、65th~122th、124th~172th、177th~210th、and 211th~219th in VP3 protein are most probably conservative. The 3D mold could be divided into A, B and C regions, the conformation of the VP3 of FMDV strain AF72 was regular, and the B-cell epitopes in VP3 probably exist in the following regions: 18 aa~23 aa, 30 aa~44 aa, 60 aa~75 aa, 113 aa~124 aa, 130 aa~142 aa, and 193 aa~220 aa. This result offers valuable information for design of FMDV multi-epitope vaccine against FMDV.

Abstract:To explore the equivalence of ISO culture media standards for domestic culture media quality control, fungus culture and chromogenic media were chosen from four domestic and foreign manufacturers, compared in quality control strain productivity ratio and bacteriostatic effect. The productivity ratioes of productivity reference stains on fungus culture are all above 0.5, and that on chromogenic media are all above 0.7, which comply with ISO international standards. After statistical analysis of these results, there are no significant difference among these culture media (P>0.05) chosen from the four culture media manufacturers in this study, which provide basic materials and basis for new national standard that is about to published to equivalent adopting ISO culture media standards.

Abstract:Methylotrophy is a kind of widespread microbe which can use carbon compound as their only carbon and energy sources. It has been reported that methylotrophy can directly use one carbon compound to transform into their own metabolic one carbon unit, then these one metabolic one carbon units can be used as energy and carbon skeleton by organisms, which is a main part in one carbon metabolism. Because this is a novel metabolic system, it can be used in the study of biological metabolism and evolution. Based on the previous study about Methylobacterium sp. MB200 in our lab, here we summarized the research improvements about methylotrophy from their taxonomy, metabolism, genomics and applications.

Abstract:Although it is widely studied as a promising bio-surfactant, biosynthesis of Rhamnolipid has not been applied in large-scale due to its high production cost. As a cheap alternative carbon source, waste edible oils have been extensively studied for the production of rhamnolipid. This paper reviewed the recent research in this field, including the influence of various waste edible oils and production, chemical structure and properties of the produced rhamnolipids. With waste edible oils, the maximum production of rhamnolipids was reported to be 24.61 g/L. The lowest surface tension was 24 mN/m and the lowest CMC of the produced rhamnolipids was 40.19 mg/L. In addition, this paper also summarized the effect of various factors on the rhamnolipids biosynthesis, such as bacteria strains, nitrogen sources, trace minerals, dissolved oxygen, pH and fermentation conditions. Based on this, the key points of the mass production of rhamnolipids with waste edible oils were also discussed.

Abstract:Organic solvent tolerant microorganism (OSTM) is a novel extremophile and it hasn't been systematically studied until 1980s. Relying on certain mechanisms, the OSTM is able to effectively defend and decrease the toxicity from organic solvents, which enable the OSTM to be potentially applied in the industrial fields such as whole-cell catalysis and environmental treatment, etc. The comprehensively understanding of the mechanisms involved in organic solvent tolerance of OSTM could be combined with genetic engineering in order to modify and optimize the various specifications of OSTM, and further broaden its application in other industrial areas. Latest studies on the tolerant mechanisms of OSTM, in this paper, will be reviewed from four aspects such as vesicle exocytosis and changes of phospholipid composition in membrane, etc. Besides, the application of OSTM in whole-cell catalysis and other fields will be introduced.

Abstract:Foot-and-mouth disease is a devastating disease of livestock that has had a significant impact on world economies and prevailed in many countries and areas throughout the world. Although the traditional inactivated vaccine is effective, there are a number of concerns with its use. So many researchers have attempted to develop new vaccines that may provide additional tools to help control FMD in future. In this paper, based on the research work in our lab, we reviewed the international research progress on the new-type vaccines of FMD including genetically engineered live-attenuated or inactivated vaccines, protein and synthetic peptide vaccines, empty capsid vaccines, and cytokine-enhanced vaccines.

Abstract:Anammox bacteria can perform anaerobic ammonium oxidation, a long missing process which contributes 30%~50% to dinitrogen gas in marine nitrogen cycling. The potential role of anammox bacteria coupling with ammonium oxidizing bacteria and archaea will benefit to elaborate the complex mechanism of marine nitrogen cycling. Furthermore, the unique cell and genomic characteristics make anammox bacteria an important model microorganism to explore the bacterial evolution. Here we re-viewed the current status of molecular ecology of marine anammox bacteria and give a perspective into the future based on our understanding of the literature and our own work.

Abstract:Environmental Microbiology is an important basic course of Environmental Engineering. Its characteristic is content broad, quick development and strong practicality, thus this curriculum's teaching has certain degree of difficulty. Some suggestions and concrete measures about teaching reform, which included curriculum's course content, teaching method, experiment teaching and assessment methods were proposed in this paper.

Abstract:Agricultural Microbiology is a professional foundation curriculum for biology, botany and environmental majors in agricultural universities. After 1999, with the increase enrollment of the national undergraduate education and rapid construction of the university, the number of majors and students increased rapidly and quality of students and talent demand of society changed dramatically. Under such condition, in order to meet the society demand of microbiology, according to the distinguishing feature of different major groups, based on strengthening the basis teaching and stretching application teaching, new curriculum teaching model and method were explored positively, and then new curriculum system was constructed. Being aroused sufficiently of the students’ subjective initiative, both the teaching quality and comprehensive quality were improved.

Abstract:The aims of microbiology experiment teaching are not only to cultivate the students’ capacity of basic operation, but also to expanse their knowledge scope. We applied the bacterial diversity on the teaching class to make the students understand the progress of microorganism genomics research. It is helpful to cultivate the students’ innovative spirit and ability. Easy to work, clear result and low cost facilitated the spread of this experiment in the university.

Abstract:“Microbiology” (color edition), with Prof. Shen Ping and Prof. Chen Xiangdong of Wuhan University as the Chief Editors, is the first 4-color microbiological teaching material in China and has been co-edited by a lot of experts in microbiological field. Besides the introduction of fundamental knowledge, it’s also a book full of creativity and inspiration, furthermore, it combines theory with practice systematically, all of which contribute much to the development of the ability of self-study and creativity for students. A large quantity of delicate illustrations enriches the book extraordinarily.

Abstract:Microbial testing slip is a new detection tool which is convenient to carry and free of media preparation. Since the key technique of the testing slip is cold water gelling agent, a new cold water gelling agent (HKG)’s water retention capacity, pH value, gels strength, source utilization by microorganisms and inhibition effect were tested in this assay. Furthermore, detection effect and specificity of HKG total plate count bacterial testing slip of food samples were compared with pour-plate method in order to evaluate its feasibility of gelling agent in microbial testing slip. HKG showed no antibacterial effect to 16 kinds of microorganisms, also the features of neutral pH, gels strength of 340.31 g/cm2 ± 48.71 g/cm2, good water retention capacity, HKG can not support the growth of microbe or be degrading by microorganism in short time (5 d). HKG testing slip had the same sensitivity (P = 0.438 > 0.05) as pour plate method in detection of 5 strains, the colony count of various test strains (P = 0.442 > 0.05) and the colony count of food samples (P = 0.718 > 0.05) of HKG testing slip had no significant difference in statistics compared with pour plate method. As the gelling agent, HKG shows good performance in bacterial testing slip, and can also improve the detection efficiency.

Abstract:Enterobacter sakazakii is an opportunistic pathogen which has been isolated at low levels from powdered infant formulas. As there are deficiencies as more time in the general method of isolation and identification of Enterobacter sakazakii, a new chromogenic medium(HKMCES) was designed in this a assay. Through detecting the reference strains, artificeially contaminated samples and natural samples, the sensitivity, specificity, detection effect and the way of pre-enrichment of HKMCSE were studied and compared with OXCSE. The results showed that the isolation of E. sakazakii was more efficiency after adequate pre-enrichment was applied. HKMCSE had the same selectivity and highly specificity as OXCSE. In con-clusion, Enterobacter sakazakii chromogenic medium were invaluable which may shorten the detection pe-riods.