Abstract:

Abstract:In industrial glutamate fermentation, intermitted feeding glucose with the help of off-line glucose measurement is generally necessary. This kind of feeding strategy could cause large variations in glucose concentration so that it is not favorable for the achievement of efficient and stable glutamate fermentation. Glutamate fermentation is characterized with typical non-growth association behavior, and during glutamate production phase glucose consumption is closely correlated with ammonia consumption. In this study, glucose concentration was controlled at various pre-determined levels by predicting glucose consumption amount and thus its concentration with the aid of on-line monitoring ammonia consumption. When glucose concentration was controlled around a lower level of 5 g/L~10 g/L, the final glutamate concentration could reach a relatively higher level of 80 g/L. In this way, the huge osmotic stress change due to the large glucose concentration variation with the intermitted feeding method could be avoided and the glutamate fermentation performance enhancement be expected.

Abstract:Armillariella. tabescens EJLY2098 was induced to produce β-mannanase with konjac fine flour (Amorphopallus rivieri) as single carbon source. This induced enzyme was then purified using DEAE ion exchange chromatography and named atMAN47. Zymologic analysis showed that the molecular weight of this β-mannanase was approximately 47 kD. The enzyme was stable when pH ranged from 5.0 to 6.5 and could be activated by Na+ and Ba2+. With an optimal temperature of 50°C. Action mode analysis of TLC re-vealed that the enzyme belonged to the endo-β-mannanase family. Being a meta-acid endo-β-mannanase, it was suitable to be applied to feed industry with a promising future as an enzyme preparation.

Abstract:A fusion expression vector pPIC3.5K-PDGFRβ was constructed to express recombinant receptor tyrosine kinase PDGFRβ and the right Pichia. pastoris transformants were screened on his-deficient plates and YPD-G418 plates by turns after electroporation of strain GS115, a high yield strain named M3 was screened. The strain M3 was cultured in a 5 L fermentor and His-GFP-PDGFRβ fusion protein was purified by Ni2+ chelating affinity chromatography. One distinct peak was obtained after elution with 250 mmol/L imidazole. Fusion protein was proved to be 90.08 kD by western blotting, and have tyrosine kinase activity by ELISA. Results showed that the receptor tyrosine kinase PDGFRβ was successfully expressed in P. pastoris and could be used as a target for small molecule selective inhibitors screening.

Abstract:Based on the Bacillus sp., isolated from Lop Nur Desert, the technology of separation and purification and the antioxidant effect were studied. After centrifugation and vacuum filtration, the deproteinization of supernatant was operated with Sevag reagent. The crude exopolysaccharide (EPS) was obtained by precipitation with ethanol. The optimum conditions for the isolation were as follow: pH 7.0, temperature 4°C, time 1.5 h, and material to ethanol ratio 1: 4. Dissolved in water, the crude EPS was fractional separated on activated carbon column (1.5 cm × 24 cm), eluted with distilled water, 60% ethanol, 95% ethanol, and the main fraction was collected. Then the EPS was purified on Sephadex G-100 gel column, eluted with NaCl (0.2 mol/L). Fractions (4 mL, each) were also combined according to total sugar by phenol-sulfuric acid method and protein content was determined by Coomassie brilliant blue. The results showed that EPS was relatively homogeneous glycoprotein. The data of antioxidation in vitro showed that the EPS had a high an-tioxidant activity, which could quench hydroxyl radical, superoxide radical and had antilipid peroxidation activity. All of these indicated that EPS was a good natural antioxidant.

Abstract:Cooperation hydrogen production was carried out using Rhodopseudomonas sp. DT and Enterobacter aerogenes. The effects of the initial ratio of Rhodopseudomonas sp. DT and Enterobacter aerogenes, culture temperature, and carbon source on the cooperation hydrogen production were investigated. The results suggested that cooperation hydrogen production rate was highly affected by the initial ratio of Rhodopseudomonas sp. DT and Enterobacter aerogenes. The mixed bacteria of Rhodopseudomonas sp. DT and Enterobacter aerogenes with 1:1 initial ratio benefited to the cooperation hydrogen production, which led the hydrogen production rate and duration of gas production to 3.1 mol H2/mol glucose and 81 h, respectively. The pH dynamics analysis of culture medium further discovered that the pH of the mixed bacteria with 1:1 initial ratio changed from 6 to 7 smaller than other conditions, which was probably fitted to produce hydrogen. Furthermore, the mixed bacteria with 1:1 initial ratio had the higher hydrogen production efficiency at temperatures of 28°C and 37°C than at 20°C, and without any hydrogen production at temperature of 50°C. The carbon sources of glucose, succinate acid, malic acid could be used to produce hydrogen by the mixed bacteria. Even the soluble starch, unused by Rhodopseudomonas sp. DT, was also decomposed by the mixed bacteria to produce hydrogen with the conversion efficiency of 8.22%. The glucose was the optimal carbon resource, and the conversion efficiency could reach to 36.11%. The results, further, implied that the cooperation hydrogen production could enlarge the use of the carbon sources.

Abstract:A sulfate-reducing bacteria strain, designated D11, was isolated from an anaerobic baffled reactor treating waste water containing sulfate. The cells of strain D11 were found to be Gram-negative, non-spore-forming, slightly curved rods, 0.6 μm~0.8 μm wide and 1.8 μm?~3.3 μm long, motile by a single polar flagellum, catalase positive and oxidase negative. The pH range for growth was 6.0~8.0 (optimum pH 7.0) and the temperature range for was 25°C~37°C (optimum 30°C). Strain D11 can use glucose, fructose, acetate, lactate, alcohol and propanediol as sole carbon source for growth and did not use glycerol, butanol, succinate and malate. The G+C content of the DNA was 62.7 mol%. Phylogenetic analysis based on 16S rRNA and DSR gene sequence showed strain D11 was closely related to the type strain of Desulfovibrio vulgaris Hildenborough and Desulfovibrio vulgaris DP4 (99% sequence similarity).

Abstract:Psychrotrophs were isolated by using four media from low-temperature sewage of sewage treatment plant in Urumqi, Xinjiang. Totally, 154 strains were obtained including 12 filamentous fungi, 46 yeasts, 6 actinomycetes and 90 bacteria. The results of tolerance tests of the isolates to salt, phenol and SDS, and enzyme producing characters of amylase, proteinase and esterase were shown. Then 60 bacterial strains were chosen for 16S rRNA gene sequencing and analysis. The blasting results showed that the strains were assigned to 13 recognized genera , and the Strain 39 exhibited 96.6% similarity to Acinetobacter lwoffii(DSM2403), indicating that it might be a novel species. These results suggested that there were a lot of psychrotrophs and rich bacterial diversity in low-temperature sewage. In addition, which maybe an important and potential library of microbial resources.

Abstract:The effect of magnetic Fe3O4 particles on cellulase in the enzymatic hydrolysis of sunflower seed hull was studied in different adding ways and additive amount. In the process of enzymatic hydrolysis of sunflower seed hull, the variations of cellulase activity, reducing sugar concentration and cellulose conversion were evaluated. After the reaction, the analysis of pH and surface tension of hydrolysate were also used to determine the mechanisms of cellulase by the magnetic effect. The results indicated that after adding magnetic Fe3O4, the cellulase activity, reducing sugar concentration and conversion of cellulose had an in-creased between the 0.5 g/L and 2.0 g/L cases after 48 h. When the additive amount of magnetic Fe3O4 was 2 g/L, the cellulase activity at 60 h was improved significantly by 25.9%. It was found that the concentration of reducing sugar was increased from 6.950 mg/mL to 8.775 mg/mL with magnetic Fe3O4 1.5 g/L. Simulta-neously, compared with the blank, which the conversion of cellulose was 47.932%, the maximum cellulose conversion of samples with adding magnetic Fe3O4 was 60.531%. Besides, the stability of cellulase activity adding in times was better than in one time. After the reaction, the final surface tension of hydrolysate with 1.5 g/L magnetic Fe3O4 was the lowest in comparison with the blank. However, no significant differences were observed in the final pH of the hydrolysate.

Abstract:A bacterial strain capable of utilizing p-nitroaniline as sole carbon source to growth was isolated from sewage sludge. This strain was identified as Microbacterium sp. PNA8 based on its morphology, physiological, biochemical properties and 16S rRNA sequence analysis. Results indicated that the optimal temperature and pH for cell growth and for p-nitroaniline degradation was 30°C and 7.0. Strain PNA8 growth and p-nitroaniline degradation was considerably faster in the presence of yeast extract. Optimum conditions, in the culture medium added to 0.4 g/L yeast extract, 0.3 mmol/L p-nitroaniline degradation rate to 100% in 4 days.

Abstract:The result of 16S rRNA analysis showed the strain AZR belonged to Staphylococcus cohnii. According to three azoreductase’s gene sequences from Staphylococcus in GeneBank, a pair of primers were designed and the azoreductase’s gene was amplified from the strain AZR’s genome successfully. The sequence contained a complete 567 bp ORF (Open Reading Frame) encoding the azoreductase, consisting of 188 amino acids. Blast in GenBank indicated that it is a novel gene, and it has been deposited with the GenBank Data Libraries under accession number EU849488. The characteristics of the protein coded by this gene were ana-lyzed by bioinformatics. The result showed that this protein belonged to the flavin protein family and was a kind of NADPH-depedent FMN reductase, and it was stable, pI 5.75, located in cytoplasm, and composed of Alpha helix, extrended strand random coil. There was a srong transmembrance domain and contained some conserved sites such as protein dinase C-phosphorylation.

Abstract:The Tn5-mob-sacB-labeled non-symbiotic pMhHN3015a of Mesorhizobium huakuii HN3015 was respectively transferred into M. huakuii HN308SR and 7653R-1SR by tri-parent mating. Two transconju-gants, HN308SRN29 and 7653R-1SRN29 were obtained. The plasmid profiles of HN308SRN29 showed that pMhHN308b of HN308SR were cured. The results implied that pMhHN3015a and pMhHN308b were incompatible. However, the results from plasmid curing tests of HN308SRN29 showed that labeled plasmid cured derivative of HN308SRN29 could not be obtained. Since the sizes of pMhHN3015a and pMhHN308a were almost the same and their positions in agarose gels were difficult to distinguished, so that two plasmids might have been recombined and transposon Tn5 transferred into the chromosome. The plasmid profiles of transconjugant 7653R-1SRN29 showed that pMhHN3015a could coexist with pMh7653Ra. Furthermore, the results from plasmid curing tests of 7653R-1SRN29 showed that two mutants, 7653R-1SRN29D-A and 7653R-1SRN29D-B were obtained. The plasmid profiles showed that 7653R-1SRN29D-A and 7653R-1SRN29D-B lost pMhHN3015a, and that 7653R-1SRN29D-B showed an additional plasmid that was named p76H4. Results from plant nodulation tests showed that HN308SRN29 lost nodulation ability. But nodulation of 7653R-1SRN29 was enhanced. 7653R-1SRN29D-A could only form null nodules. How-ever, 7653R-1SRN29D-B lost its nodulation ability.

Abstract:Endophytic fungi inhabited in Ginkgo biloba L. were isolated, and 55 endophyte strains were obtained. Among the strains, 28 produced sterile mycelia on PDA plates, accounting for 50.9% of the total fungi. In addition, there were ten Penicillium spp., six Aspergillus spp., four Alternaria spp. and three Chromosporium spp., and one yeast, Mucor, Acremoniella, and Fusarium, respectively. Antimicrobial activity of fermentation cultures of these 55 strains were investigated against seven tested microorganisms. Twenty-three strains with antimicrobial activity were obtained, among which eleven produced sterile myce-lia, accounting for 47.83% of the fungi with antimicrobial activity. The strain with the highest antimicrobial activity was determined to be Xylaria venosula Speg., according to its morphological features and molecular analysis. As a novel antimicrobial resource, endophytic fungi in G. biloba have a potential prospect.

Abstract:Nisin is a cationic antimicrobial peptide produced by some lactic acid bacteria. However, expression of nisin resistance protein (NSR) could confer nisin resistance on some non-nisin-producing Lactococcus lactis. To deeply elucidate molecular mechanism underlying NSR-mediated nisin resistance, an NSR mutant with N-terminal 38 amino acid residues deleted (NSRΔ38) was overexpressed in Escherichia coli by fusion with GST. Purified NSRΔ38 was obtained through glutathione (GSH) affinity chromatography followed by cleavage of GST tag. Putative proteolytic activity of NSRΔ38 was determined in vitro against nisin. Antimicrobial activity analysis revealed that nisin lost its bactericidal activity after incubation with NSRΔ38. Further reversed-phase high performance liquid chromatography (RP-HPLC) analysis indicated that NSRΔ38 displayed proteolytic activity against nisin, thus inactivating the antimicrobial peptide. The current study paves the way for in-depth functional studies on NSR.

Abstract:Bovine Lactoferricin is a fragment of polypeptide which derives from N-terminal of bovine lactoferrin when it is digested by pepsin in acid condition. It has many biological functions. This study was designed to research the antibiosis spectrum of LfcinB and the key functional active site of the LfcinB by amino acid substitution and peptide sequence modification. Antimicrobial spectrum of the artificial synthesized LfcinB was determined by agar-well diffusion method. The antibacterial active sites were confirmed by minimal inhibitory concentration assays. After the Cysteine at the third site and the tryptophan at the eighth site of LfcinB were substituted by alanine, or two cysteine of LfcinB were respectively, the minimal inhibitory concentration of the three artificially modified LfcinBs was assayed. Results showed that LfcinB had a broad-spectrum of antibiosis, it could restrain various bacterials, such as Gram-positive bacteria, Gram-negative bacteria, fungus and mycetes. LfcinB was stable to heat and pH, it could not be inactivated by many protease. The tryptophan at the eighth site and the intramolecular disulfide bond formed between two cysteins played a key role for antibiosis, as the functional active sites of LfcinB.

Abstract:Interdelta fingerprinting has been carried out for Saccharomyces strain typing by using 45 Saccharomyces isolates from spontaneous fermentation of Cabernet Sauvigon in Ningxia. The dynamic changes of the Saccharomyces cerevisiae strains were observed, which can provide an approach for better control of the fermentation process. The result revealed that 5 genetic patterns were distinguished by interdelta finger-printing among the total Saccharomyces isolates. The genetic pattern I to V accounted 71%、13%、9%、5.0%、2.0% respectively for the proportion of the total Saccharomyces isolates. Therefore, the genotype I was the dominant strain during the fermentation. Moreover, the influences on the genotype, the number and the pro-portion of S. cerevisiae strains by sulphur dioxide added before fermentation were also demonstrated in this study.

Abstract:Lactobacillus casei was selected as an antigen delivery vehicle for the development of oral vaccine to express recombinant LTB and porcine parvovirus (PPV) VP2 protein. The fusion protein gene encoding PPV VP2 protein and LTB, was cloned into the surface expression vector pPG, and then the recombinant expression vector pPG-VP2-LTB was electrotransformed into Lactobacillus casei 393, generating re-combinant strain pPG-VP2-LTB/L. casei 393. After induced by 2% Lactose in MRS broth, an about 78 kD protein was detected in the recombinant Lactobacillus casei by SDS-PAGE. The result of Western blot indi-cated that the protein possessed the antigenic specificity same as the native virus protein. The result of the whole bacteria cell ELISA indicated that the LTB protein was expressed at the same time. The results of in-direct immunofluorescence test and immuno-gold electron microscopy showed that the interest protein was expressed on the surface of L. casei 393. The results provide potential for the development of lactic acid bacteria oral vaccine of PPV, which used LTB as mucosal adjuvant.

Abstract:In order to breed excellent diastatic strain using for Chinese Rice Wine fermentation, UV, LiCl, BaCO3 and natural selection to mutagenize (Aspergillus flavus) YA were used. Mutant (Asp. flavus) YA4.9 was obtained with properties as follows: growing fast, mycelium dense-dumpy, not producing aflatoxins. The optimum culture time of moldy bran was 32 hours, the glucoamylase activity and α-amylase activity were 30952 U/g and 14357 U/g, comparing to the parent strain, increased by 103.46% and 65.08%, respectively, the finished Chinese Rice Wine has good quality. The inherited characters were steadily by many generations.

Abstract:21 cold-active strains which produced cold-active cellulase were isolated from Bohai Bay. One of the strains CNY01 was a kind of Trichoderma viride and its cellulase activity was 67.30 U/mL. Through UV and DES mutation, the strain CNY086 was bred and its cellulase activity was 92.17 U/mL. The strain CNY086 had stable ability to produce cellulase. Through orthogonal experiment, the optimal condition of the fermentation medium had been tested. The suitable medium was that straw power 1.20%, bran 0.70%, (NH4)2SO4 0.50%, KH2PO4 0.55%, in this condition the cellulase activity came to 108.55 U/mL.

Abstract:21 cold-active strains which produced cold-active cellulase were isolated from Bohai Bay. One of the strains CNY01 was a kind of Trichoderma viride and its cellulase activity was 67.30 U/mL. Through UV and DES mutation, the strain CNY086 was bred and its cellulase activity was 92.17 U/mL. The strain CNY086 had stable ability to produce cellulase. Through orthogonal experiment, the optimal condition of the fermentation medium had been tested. The suitable medium was that straw power 1.20%, bran 0.70%, (NH4)2SO4 0.50%, KH2PO4 0.55%, in this condition the cellulase activity came to 108.55 U/mL.

Abstract:The particularities of oil suspension formulation can raise the invasive rate of Hirsutella sinensis to host of Hepialidae for the commercialization of artificial cultivation of Cordyceps sinensis. So it is important to develop a high cell viability oil suspension formulation of C. sinensis spawn. According to the char-acteristics of the oil suspension formulation, MTT assay is adapted and optimized. The result is as follows: reaction time 120 min, reaction temperature 37°C, methylbenzene as extracting agent, and a positive linear correlation established between active cell weights and cell viability. Varieties and concentrations of assis-tance agents in oil suspension formulation have been selected with the refined MTT assay, and further opti-mized together with cell concentrations through orthogonal experiment. The optimal combination project was obtained, namely, cell concentration 0.15 g/mL, aluminium stearate 60 mg/mL, and SPAN-80 50 μL/mL. Results of stability test on the oil suspension formulation indicate that cell viability can maintain above 90% at 4°C after one month.

Abstract:The Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R mutants of Candida albicans sterol 14α-demethylase (CACYP51) were constructed and heterologously expressed in D12667, the reconstructed strain with the deletion of CYP51 gene of the Y12667. With the strains obtained and microsome enzymes separated, the western blot and the ultraviolet absorption spectrophotometry were used to qualitative and quantitative detect the expressed protein, the GC-MS was used to detect the metabolism activity of the protein. The results showed that, the target protein expressed successfully in the reconstructed strains, with the expression level up to 25% of the total microsome proteins. The results also showed that, the wild type protein had the catalytic activity to its nature substrate. While after alteration the wild gene with Y118A、Y118F、Y118T、S378A、S378T、H310A、H310R by a single base substitution, the catalytic activity of protein markedly decreased respectively. So the wild type and mutation CYP51 were expressed successfully in Saccharomyces cerevisiae and the expression products preserved the activity to metabolism their nature substrate.

Abstract:A pathogenic bacterial strain QXL0711B was isolated from freshwater shrimp (Macrobrachium nipponense) suffering with soft-shell syndrome. The 50% lethal concentration (LC50) of strain QXL0711B was 1.47×106 CFU/mL, which showed that strain QXL0711B was rather strong virulent to Macrobrachium nipponense. Strain QXL0711B was gram negative and had β-hemolytic activity on sheep blood agar. By means of API 32E identification and 16S rRNA sequence analysis, strain QXL0711B was identified as Aeromonas veronii biovar sobria (locus number: FJ808727), which was the closest relative to Aeromonas veronii strain (locus number: X71120) and Aeromonas veronii biovar sobria strain (locus number: AY987729) with 99% homology. In addition, strain QXL0711B was highly sensitive to ceftriaxone ceftazidime ciprofloxacin enrofloxacin and norfloxacin.

Abstract:Cantharellus Adans. ex Fr., a member of the Cantharellaceae, Cantharellales, Homobasidiomycetes, Basidiomycota, is a widely distributed macro-fungal genus with an independent evolutionary lineage. It currently includes 65 species, of which 9 were recorded in China. In this article, research history of the genus was briefly reviewed and some controversial conclusions, especially the demarcation and naming of some taxa, discrimination among similar species, problems on C. cibarius Fr. and C. tubaeformis Fr.: Fr. complex, as well as their ecological conservation and bionic cultivation, are discussed based on the authors’ findings. Proposals for further research on biodiversities and sustainable utilizations were put forward at last.

Abstract:Tautomycin is one of well-known specific protein phosphatase inhibitors and exhibiting potent antifungal ability, especially to Sclerotinia sclerotiolum. This article reviews the recent research progress of tautomycin, focusing on its inhibition region and biosynthesis.

Abstract:Advances in mechanism and application of the heating effect in breeding of microorganism are reviewed in this paper. Heat produces mutagenesis effect and screening effect. Heating mutagenesis effect is occurred through the substitution of G-C base pair induced by heat, and heating screening effect produces higher forward mutation rate induced by other mutagens.

Abstract:The basical structure of diketopiperazines is a cyclic dipeptide condensed by two amino acids. Because of the stable framework of the six-member ring structure, and having two hydrogen bond donor and two hydrogen bond receptor, DKPs have become important chemical pharmacophores, with strong biological activities and pharmacological activities in the drug. A series of cyclic compounds were found from marine organisms in recent years, research showed that their functions are not limited on anti-bacterial, cytotoxic activity, and so on, but also playing an important role in regulatory mechanism of quorum sensing as signal molecules, they have become research hot point in ecological chemistry. This paper reviewed the research progress of diketopiperazines found in the marine microbial metabolites, and the future study trends was discussed and outlooked.

Abstract:The yeast Sacchromyces cerevisiae is most widely used for producing bioethanol in alcoholic industry due to its higher ethanol yield and fermentation rate. However, the toxic effect of accumulated ethanol is one of the main factors, which limit high ethanol production. Thus, investigating the mechanisms of yeast ethanol tolerance will provide the basis for solving the industrial problem. This article reviewed the mechanisms of Sacchromyces cerevisiae ethanol tolerance focusing on its cell physiological behaviors, structure and biochemical composition, as well as its genetic basis.

Abstract:In order to meet the requirements of cultivating the practical abilities and creativities of students who receive higher education, we initiated the reformation of education in the microbiology experiment teaching methods, implementing a system for module-based education, carefully monitoring every link in teaching, combining the encouragement and strict requirements together, adopting a proper way of assessment. It is proven that the implementation of the educational reformation mobilizes the interests of students and enhances the comprehensive qualities of students, which accomplishes the purposes of teaching.

Abstract:Dot-ELISA and tissue blot-ELISA with monoclonal antibody to detect Cymbidium mosaic virus (CymMV) were established. 8000-dilution CymMV monoclonal antibody could be adopted to detect CymMV infecting leaf extract within a dilution limitation of 1:10240. CymMV could still be detected in the eighth print by tissue blot-ELISA . Similar results were shown between the fifth print by tissue blot-ELISA and 80-dilution of infected leaf extract by dot-ELISA. Comparison tests showed that the commonly used tissue blot-ELISA was less sensitive than dot-ELISA. It could illustrate that CymMV monoclonal antibody was more specific and sensitive than the polyclonal antibodies. The improved tissue blot-ELISA is more simple than dot-ELISA, and is suitable for fast detection with a large number of samples in the field.