Abstract:

Abstract:A bacterial strain was enriched and isolated from rotten cyanobacteria of Taihu Lake by dilution-plate method, using microcystins as selective material of microcystin-degrading bacteria, which was extracted and purified from cells of cyanobacteria. Based on morphological, physiological characteristics and 16S rDNA sequence analysis, the strain is preliminarily identified as Micrococcus luteus (GenBank accession number is GQ143751). The results of microcystin-degrading experiments show that the strain could hardly degrade microcystins but could enhance the microcystin-degrading capability of another strain Stenotrophomonas acidaminiphila. When the strain is mixed with Stenotrophomonas acidaminiphila, the microcystin-degrading capability of mixed bacteria is improved 66.7% compared with Stenotrophomonas acidaminiphila.

Abstract:Both of the phosphoenolpyruvate carboxylase (PPC) and phosphoenolpyruvate carboxykinase (PCK) could catalyze the reaction from phosphoenolpyruvate (PEP) to oxaloacetic acid (OAA) in the pathways of anaerobic mixed acid fermentation for E. coli. In addition, the reaction catalyzed by PCK generates ATP, which is more beneficial to the growth of the strain and the succinic acid production theoretically. In this study, we constructed a ppc defective strain using λ-Red homologous recombination system with the E. coli W3110 (△pfl, △ldh) as the parent strain. Based on that, Bacillus subtilis pck was overexpressed. The preliminary anaerobic fermentation experiments showed that both strains partially recovered the ability to consume glucose through the overexpression of pck. Besides, the ppc defective strain showed the most excellent performance, the rate of glucose consumption and succinate production were 4.2 and 15.3 folds as much as those of the parent strain, respectively.

Abstract:The enzyme activity of some key metabolic enzymes (pyruvate kinase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase and ethanol dehydrogenase) in Saccharomyces cerevisiae with YEPD medium were compared with malic aicd, citric acid and succinic acid mixed medium. The result showed that after adding malic acid, enzymatic activity of pyruvate kinase, isocitrate dehydrogenase, malate dehydrogenase and ethanol dehydrogenase respectively declined 34.82%, 57.23%, 39.15% and 12.10%; after adding citric acid, enzymatic activity of pyruvate kinase, isocitrate dehydrogenase and malate dehydrogenase respectively declined 50.17%, 42.20% and 48.40%; after adding succinic acid, enzymatic activity of pyruvate kinase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase and ethanol dehydrogenase respectively declined 34.16%, 34.16%, 50.87%, 50.87% and 12.37%. Pyruvate kinase, isocitrate dehydrogenase and malate dehydrogenase had bad tolerance to three kinds of organic acids, tolerance of glucose-6-phosphate dehydrogenase and ethanol dehydrogenase to three kinds of organic acids had selectivity.

Abstract:An autotrophic oleaginous Chlorella vulgaris with lipid productivity at 28.6 mg/(L?d), was isolated from the water sample of Dianchi Lake in Yunnan province. The effects of nitrogen sources, nitrogen concentrations, and inorganic carbon (NaHCO3) on cell growth as well as lipid accumulation of C. vulgaris were investigated. The results showed that the optimum nitrogen source and nitrogen concentration were sodium nitrate and 123 mg/L, respectively. Lipid content decreased with the increasing of nitrogen concentration. Biomass productivity and lipid productivity of C. vulgaris remarkably rose by addition of NaHCO3. The optimized concentration of NaHCO3 was 800 mg/L. Under the optimal conditions, biomass productivity and lipid productivity of C. vulgaris could reach up to 332.8 mg/(L?d) and 100.2 mg/(L?d), respectively, which were 3.6 and 3.4 times as much as the control group.

Abstract:A new electrochemically active bacterium (exoelectrogen), strain S2, was isolated from coastal marine sediments of Xiamen. The phylogenetic trees based on 16S rRNA and gyrB gene sequences showed that strain S2 formed a lineage within the genus Shewanella and had high similarity (98.5% and 87.0%, respectively) with strain S. oneidensis MR-1. The phenotypic characteristics indicated strain S2 could be distinguished easily from S. oneidensis MR-1 by its culture conditions such as pH, NaCl tolerance and carbon source utilization. Based on these results, it is identified as Shewanella sp. S2. The preliminary current generation experiments showed that S2 could use lactate and xylose for electricity production. When lactate was used as a fuel, the MFC had highest voltage (150 mV) and current density (66.1 mA/m2).

Abstract:In this study, antimicrobial activity of the culture supernatant of Streptococcus thermophilus CGMCC 1.1864 was investigated with the agar diffusion method. The subsequent experiments results indicated the antimicrobial activity of the supernatant were not due to the existence of hydrogen peroxide and organic acid in the solution. The antimicrobial spectrum assays showed that the supernatant could inhibit the growth of both Gram-negative bacteria and Gram-positive bacteria. Heat stability test was also performed with the antimicrobial substance and no activity lost was observed after 2 h incubation at 100°C or 20 min at 121°C. However, its activity was reduced significantly if the boiling samples were transferred to ?20°C freezer for storage immediately. It was also tolerable to changes of pH levels, no significant reduction of its antimicrobial activity was observed at pH 2.0 through pH 9.0. The treatment of proteases and α-amylase could completely abolish the antimicrobial activity of the supernatant, while no activity loss was observed when treated with catalase. These results demonstrated that the antimicrobial substance belonged to bacteriocin family and was named as thermophilin ST9 tentatively. Since thermophilin ST9 could specially adsorb to the producing strain, pH-adsorption method was chosen to purify the bacteriocin, and subsequently the SephadexG-25 column chromatography was adopted to eliminate other proteins. Elution solution was further concentrated with freeze-drying method to obtain thermophilin ST9 powder. Purified thermophilin ST9 was subjected to Tricine-SDS- PAGE analysis and its molecular mass was determined to be 5.0 kD.

Abstract:To study the mechanism of adhesion of Lactobacillus plantarum ST-Ⅲ on Caco-2 cells, the adhesive ability of the bacterial cell to the mammal cells was investigated by fluorescence labeling with CFDA-SE and the components on the cell surface involved in the adhesion were extracted. After treatments by chemicals and enzymes, it was shown that pepsin, trypsin, LiCl, phenol, guanidine hydrochloride and heat treatment could signigfantly decrease the adhesive ability of ST-Ⅲ, indicating that the S-layer protein or lipoteichoic acid may be related to the adhesion of ST-Ⅲ to Caco-2 cells. The suppressive test and reversible binding test confirmed that the S-layer protein mediated the adhesion process, whereas the lipoteichoic acid on the bacterial cell surface did not participated in the adhesion. The results showed that the crude surface protein extracts of ST-Ⅲ might contain S-layer protein which participated in the adhesion. The SDS-PAGE assay showed that the crude extracts was composed of three proteins with molecular weight of 72.7 kD, 34.1 kD and 24.3 kD respectively.

Abstract:The impact of magnesium on growth, magnesium tolerance and enrichment features, as well as changes in activity of antioxidant enzymes under high-magnesium-concentration stress in Armillariella mellea were investigated. Magnesium at concentrations between 3?15 g/L in growth media promoted the growth of mycelia of A. mellea, but inhibited the growth at concentrations above 19 g/L. The formation and biomass production of fruiting body were not affected when magnesium concentration was below 11 g/L. At magnesium concentrations above 11 g/L the fruiting body formation stopped. The Mg content in crustose aerial hypha and rhizomorphs of A. mellea increased with increasing Mg concentration in growth medium up to a concentration of 16 g/L, but ceased to increase when the Mg concentration in medium was over 16 g/L. The Mg content in fruiting body of A. mellea grown on medium containing 9 or 10 g/L Mg was significantly different from that on control medium. The activity of antioxidant enzymes including peroxide (POD), catalase (CAT) and superoxide dismutase (SOD) in crustose aerial hypha and rhizomorphs of A. mellea, as well as the differences in the activity of antioxidant enzymes increased with increasing Mg concentration in growth medium.

Abstract:The mixture of broad bean and wheat flour during fermentation was used to screen antagonistic bacteria against aflatoxigenic Aspergillus flavus. A strain L4 with strong antifungal activity against the aflatoxin-producing Aspergillus flavus was selected using broadbean agar medium (BAM). According to its morphological, physiological and biochemical characteristics and 16S rRNA gene sequence homology analysis, L4 was identified as Bacillus subtilis. When L4 and Aspergillus flavus were co-cultured for 15 days, the weight of the mycelium and the production of aflatoxin B1 were both significantly lower than those of Aspergillus flavus cultured without L4. The accumulation of AFB1 was inhibited significantly, the values of the reduction was 93.7%. When L4 culture supernatant was mixed with the spore suspension of A. flavus at ratio of 1: 1 and then inoculated on corns, the germination and growth of A. flavus was inhibited completely.

Abstract:Actinomycete strain PW0852 with high production of α-glucosidase inhibitor was isolated from soil samples. Based on the results of morphological, physiological, chemotaxonomic characteristics and 16S rRNA analysis, strain PW0852 was placed within the genus Streptomyces and identified as the species Streptomyces lavendulae. After fermentation in a 10 L fermentor, α-glucosidase inhibitors were accumulated in the harvested broth of strain PW0852. The mixed-type α-glucosidase inhibitor GIB852 we obtained was isolated and purified after ultra-filtration, nano-filtration, resin-adsorption and desiccation. GIB852 could efficaciously inhibit human pancreatic α-amylase and α-maltase glucoamylase. The inhibition of maltase is stronger than the same dose of the commercial α-glucosidase inhibitor miglitol 28.7 times, while the inhibition of α-amylase is weak. GIB852 could significantly depress blood glucose levels in mammalian systems and be developed towards a possible therapeutic agent for diabetes.

Abstract:Ninety-seven strains of endophytic fungi were isolated from the roots, stems and leaves of natural Scutellaria baicalensis Georgi, in which, thirty-three from the living stage and sixty-four from the riping stage. They were classified as thirty-eight fungal genera in which Alternaria is the dominant genus. The distribution of genera in riping stage was more diversified than that in living stage. The inhibitory activity screening was conducted with fourteen species of microbes. The results showed that ninety-one strains, accounting for 95.8% of all the isolates, showed inhibitory activity to one indictor or more. Some endophytic fungi showed remarkable inhibitory activity to Escherichia coli CGMCC1.1103, Bacillus subtilis CGMCC1.769, Bacillus cereus ATCC1361, Enteropathogenic E. coli ATCC49105, Candida albicans ATCC10231, Pestalotiopsis microspora CNUMB2PM01. All fungal strains of endophytes obtained in this study showed no inhibitory activity to Staphyloccocus aureus CGMCC2.282 and Rhodotorula rubra ATCC12600.

Abstract:To explore the expression and effects of transfection of the HSV-2 LAT ORF2 gene on Vero cells against apoptosis induced by 5-FU. Recombinant plasmid pEGFP-ORF2 was transiently transfected into vero cells, expression was determined by green fluorescent protein and RT-PCR, changes of cell apoptosis were determined by Giemsa stain, MTT assay and DNA ladder. We found that the green fluorescent protein has a high expressed efficiency in Vero cells, target gene was detected by RT-PCR. Vero cells transfected with pEGFP-ORF2 induced by 5-FU have no changes in cytomorphology. MTT assay showed that the cells activ-ity transfected with HSV-2 LAT ORF2 remarkably higer than the negative control, While there were no such remarkable changes between them and normal cells. DNA ladder showed that there was no DNA fragment. Therefore we concluded that HSV-2 LAT ORF2 gene was expressed effectively in vero cells and can protect cells from apoptosis induced by 5-FU.

Abstract:Biosorption is one of the high performance and low cost methods for treating wastewater contained low concentration of heavy metal ions. In this paper, the activated sludge from sewage treatment plant was treated by enrichment and cultivation in first step, and then magnetotactic bacteria MTB-11s were obtained by separating and purifying the bacteria obtained in former step. The 16S rDNA analysis showed that the strain of the MTB-11s belonged to Delftia. The results of batch adsorption experiments over magnetotactic bacteria indicated that the magnetotactic bacteria MTB-11s had significant selective adsorption to different metal ions, the adsorption of Ag (I) was a rapid process and almost independence on the temperature. The optimal pH for the adsorption of Ag (I) was 4?8, and the adsorption rate increased with the increase of dry cell concentration and approached to stable finally. With the increase of the initial concentration of Ag (I), the adsorption rate increased to a maxium and then decreased. The Cu (II) or Co (II) coexisted with Ag (I) could promote the adsorption of Ag (I) in the condition of adequate bacteria or low initial concentration of metal ions, otherwise competitive adsorption was found.

Abstract:GacA is a component of GacS/GacA two-component system. In this study, Pseudomonas sp. M18 gacA gene had been successfully cloned and expressed in vector pET28b (+). Plasmid sequencing showed that two bases were different from Pseudomonas sp. PAO1 but did not change the amino acid sequence. The constructed recombinant plasmid was transformed to E. coli BL21 (DE3) by heat shock method and expressed under induction of IPTG. Ni-NTA was used to purify this his-tag GacA. Its purity reached to 98%. By Peptide Mass Fingerprinting, the obtained protein was confirmed as GacA. Circular dichroism data showed that GacA contained 4% α-helix, 48% β-sheet and 48% random coil. Purified GacA protein could be used for further analysis such as crystal structure, biological characteristics and GacS/A two-component system.

Abstract:Two strains were selectively isolated from the sample of Mengniu fermented milk product on modified MRS medium. Strain BB-12 was selectived by morphology observation, it was consistent with the characteristics of Bifidobacterium sp.. On the basis of polyphasic approach: morphology, physiology and molecular properties, it was evident that the strain BB-12 belonged to Bifidobacterium animalis subsp. lactis. Analysis of 16S rDNA sequences (GenBank accession No. GU116483) and atpD gene sequences (GenBank accession No. GU116482) revealed that the latter had clear separation of two subspecies while the former was not possible since their sequences displayed at least 99.1% homology.

Abstract:Archaea, as the third life form distinguished from eukaryotes and prokaryotes, plays an important role in indicating geological environment and revealing the global elements cycle. It has become one of the most important topics in the field of biogeochemical presently. The paper reviewed the application of the archaea membrane in geological research, including the deficiency and prospect of the so far studies in the area.

Abstract:Anabaena sp. strain PCC7120, an ancient group of photosynthetic prokaryotes, have served as an excellent model system for analysis of fascinating biological phenomena such as photosynthesis and its regulation, cell differentiation and N2 fixation, metabolism of nitrogen, carbon, and hydrogen, resistance to environmental stresses and molecular evolution. Apart from excellent basic research on heterocyst development and gene rearrangements, Anabaena strains have been extensively investigated for biotechnological applications such as production of drug and food, nitrogen biofertilizer, for hydrogen production and ammonia excretion, pesticides infested soils, bioremediation of oil, and production of biological fuel. However, the low expression rate was the neck for the use of this system. To improve the foreign protein expression rate, genetic transformation system of Anabaena sp. strain PCC7120 were extensively investigated such as vector (including promoter, reproducer, select marker etc.), foreign gene modification (coden and SD sequence), host adjustment, transformation method. Besides used for gene function research, Anabaena PCC7120 was used as host expressed many foreign proteins. Constructing Anabaena PCC7120 mutant and finding the best culture condition specially for expressing foreign proteins may be one of the new research directions.

Abstract:Polysaccharides derived from mushrooms have attracted much attention of research in the past three to four decades because of their potent anti-tumor, anti-senility and immunomodulation properties. In this paper, some extraction methods for fungal polysaccharides, including water extraction, acid extraction, alkaline extraction and enzyme extraction etc., were discussed. The mechanism, application and influence of different factors in the extraction process about these methods were furthermore analyzed.

Abstract:A reformation probe of bio-pharmacy major of higher vocational education has been practiced on background of the development of the higher vocational education theories and the bio-pharmaceutical industries. We analyzed the nessecities, bases, theories and characters of this reformation. And we also discussed the items, content, effects and prospects of this reformation. We established education model on the basis of cooperation of the college and the enterprises, and the tie of employment and learning. We reformed the curricula and the teaching content. And we established a practical education system with the core of practical training center of inside and outside the campus.

Abstract:The rapid development of network information technology has permeated into traditional classroom teaching, and changed the teaching idea, mode and organization style of classroom teaching. According to teaching model of “creating situations – asking questions – task decomposing – researching cooperatively – forming conclusion – evaluating online” utilization under network environment, network technology is fully integrated with microbiology curriculum teaching practice to realize the curriculum integrated with informational technology effectively. Teachers may try to change the existing teaching methods, avoid boring teaching, display the whole new perspective and improve teaching quality and results.

Abstract:We discovered some primary reasons for the poor learning efficiency of students in medical microbiology study by the analysis and investigation of the tests and answer sheets. There are some thinking barriers, such as recognition errors, reiteration of interdisciplinary knowledge, unclear concepts, ambiguous imaginal thinking, poor ability in knowledge migration, and negative migration. We analyzed these barriers with the consideration of the characteristics of the course and provided some teaching strategies in the paper.

Abstract:Genetic engineering is at the forefront of life sciences; its content is with international cutting-edge nature, and in rapid development and updating. To train students with comprehensive quality who are able to adapt to globalization, bilingual teaching has been conducted for “Genetic Engineering” course in Bioengineering major of College of Life Sciences, Fujian Normal University, since 2006. Based on the practice of bilingual teaching of genetic engineering in the past few years, this paper describes the experience of bilingual teaching, including the choice of teaching content and bilingual teaching materials, teaching methods and modalities of reform, as well as the utilization of network resources, and explores the existing problems and strategies.

Abstract:Filamentous fungi play an important role in industry, agriculture, medicine and biological fundamental research. More and more attention has been paid to fungal breeding and gene functional analysis via genetic transformation technology. However, the extraction of fungal DNA was labor intensive and time-consuming, which makes it difficult to perform high-throughput screening of transformants through PCR technology. In this paper, a rapid DNA extraction method was established for filamentous fungi (take Aspergillus for example). DNA was easily obtained by exposing the fungal mycelia in 10 × TE buffer to microwave. RAPD and PCR experiments demonstrated that the extracted DNA satisfied the requirements of PCR amplification. These results provided a foundation for the high-throughput screening of filamentous fungal transformants.

Abstract:The evaluation of antibiotic susceptibility of lactic acid bacteria (LAB) is a major part of the safety of probiotic foods. However, there is no international standard method of the susceptibility testing of LAB till now. We investigated 6 culture media and selected a proper commercial one from them. We optimized the agar disc diffusion method and assayed 9 strains of LAB encompassing the genera Lactobacillus, Bifidobacterium, Streptococcus and Lactococcus for susceptibility to 51 antibiotics on RCA agar. The optimized method proved to be an applicable technique for antibiotic susceptibility testing of LAB. This contributes to the establishment of a standardized procedure for antibiotic susceptibility testing of LAB.

Abstract:To establish the acid polyacrylamide gel electrophoresis (A-PAGE) analyzing method of peroxidase isoenzymes in photosynthetic bacteria. According to the number and the grey scale of bands, the conditions of the A-PAGE were optimized by the orthogonal design and the genetic algorithm. The results indicated that when the Triton X-100 concentration in the gels was 0.31%, the ultrasonic time was 19 min, the Triton X-100 concentration in the samples was 0.79%, the clear peroxidase isoenzyme zymograms of Rhodopseudomonas palustris were obtained, when the Triton X-100 concentration in the gels was 0.27%, the ultrasonic time was 16 min, the Triton X-100 concentration in the samples was 0.76%, the clear peroxidase isoenzyme zymograms of Rhodobacter sphaeroides were obtained. The paper set up a simple and rapid method for the analysis of peroxidase isoenzymes in photosynthetic bacteria.