Abstract:

Abstract:To explore the erythromycin penetration through Staphylococcus epidermidis biofilm. The penetration ratio of erythromycin through Staphylococcus epidermidis biofilm of 1457, 1457-msrA and S68 isolates were detected by biofilm penetration model at different time points. The RNA/DNA ratio and the cell density within the biofilms were observed by confocal laser microscope and transmission electromicroscope, respectively. The penetration ratios of erythromycin through the biofilms of 1457, 1457-msrA and S68 after 36 h were 0.93, 0.55 and 0.4, respectively. The erythromycin penetration ratio through 1457 biofilm (with 0.58 after 8 h) was faster than two others (with 0.499 and 0.31 after 24 h). The slower growth rate of the cells in biofilm was shown, with reduction of RNA/DNA proportion observed by confocal laser microscope through acridine orange stain. Compared with the control group observed by transmission electrmicroscope, the cell density of biofilm air face was lower than that of agar face, with more cell debris. Erythromycin could penetrate into the Staphylococcus epidermidis biofilm, but couldn’t kill the cells thoroughly. The lower growth rate of the cells within biofilm could help to decrease the erythromycin susceptibility.

Abstract:Arginine Deiminase(ADI)was purified to homogeneity using ammonium sulfate precipitation, Q-Sepharose Fast Flow anion exchange chromatography and SephadexG-75 gel filtration chromatography. This purification protocol resulted in a 34.5-fold purification of ADI with 31.4% final yield. A molecular weight of about 190 kD determined by native gradient polyacrylamide gel electrophoresis. The enzyme has only one kind of 46 kD subunit determined by SDS-PAGE. Combining the results from the two kinds of electrophoresis, the authors deduce that the enzyme may be a tetramer. The optimum pH and temperature for lipolytic activity of ADI was pH 6.5 and 50℃, respectively. It was extremely stable at 45℃ and retained 97.9% of its original activity for 30 min. The stability declined rapidly as soon as the temperature rose over 50℃. ADI was highly stable in the pH range from pH 5-8. ADI acted on L-arginine but not on D-arginine. ADI catabolism was dependent on metal ions. At their adequate concentration, Mn2+, Mg2+ and Co2+ were the effective promoter, while superfluous Zn2+and Co2+ inhibited ADI activity. L-citrulline did not act on ADI, but L-ornithine inhibited ADI activity. The degradation of L-arginine with ADI catalysis was according to simple Michaelis-Menten equation. The Michaelis constant was 3.2686 mmol/L and the maximum velocity was 2.44 μmol/min.

Abstract:The Gram-negative, facultative anaerobic strain, LZ-5 producing alkaline cellulase had been screened and isolated from the alkaline soil of paper mill. The strain was identified to be a kind of genus Vibrio. The cellulase activity of culture liquid was 5.8 U/mL.The primary study on enzymatic properties showed: optimum temperature of 40℃, optimum pH of 9.0, with stable enzymatic activity under alkaline condition. The strain LZ-5 was tested by the experiments of subculture and the results showed that the strain LZ-5 had genetic stability.

Abstract:Chlorella pyrenoidosa No.2 was screened from five species of microalga Chlorella sp. for its higher lipid yield. Effects of medium components and culture conditions on cell growth as well as lipid accumulation of C. pyrenoidosa No.2 were investigated and the results showed that the optimum medium recipe was 20.0 g/L glucose, 0.08 g/L glycine, 1.0 g/L K2HPO4·3H2O, 0.4 g/L MgSO4·7H2O and 0.004 g/L FeSO4·7H2O. The optimum culture temperature, initial pH, shaking rate and light intensity were 28℃, 6.0, 130 r/min and 650 Lux, respectively. Biomass and lipid content increased from 3.73 g/L and 40.15% to 6.56 g/L and 59.90% when Chlorella pyrenoidosa No.2 was cultivated under the above optimal conditions for 7 days, with lipid yield raised by 162%. Chlorella pyrenoidosa No.2 could produce lipid with xylose as carbon source, and so is potential for lipid production from renewable materials such as lignocellulose. GC analysis demonstrated that the fatty acid composition of the lipid was similar to that of vegetable oil and its unsaturated fatty acid content reached around 71%, thus it is a promising material for biodiesel production.

Abstract:The leakage of genetically engineered microorganism (GEM) at the beginning of operation was the important content for ecological risk assessment when GEM was inoculated in a membrane bioreactor (MBR) for bioaugmentation. The effects of different operating conditions on leaking density and intercepting efficiency of GEM were investigated in a submerged microfiltration MBR at the beginning of operation. The interception characteristics were also discussed. The results showed that different operating conditions had different influences on intercepting efficiency: higher sludge concentration was profit for interception, while higher aeration intensity and flux had opposite effects on interception. When the inoculated density of GEM was 1.0×1010 CFU/mL, the leaking densities varied from 1.0×102 CFU/mL to 2.5×102 CFU/mL under different operating conditions at the beginning of operation and the maximum intercepting efficiency could be higher than 8 lg. The main factors determining intercepting efficiency at the beginning of operation were membrane module interception, sludge adsorption as well as suspended GEM transfer inhibition and their contribution shares under certain conditions were 82.3%, 14.9% and 2.8%, respectively. Gel layer formation during MBR stable operation was helpful to increase intercepting efficiency. The contribution shares for GEM interception of membrane module, sludge and gel layer were 75.3%, 10.7% and 14.0%, respectively, under certain conditions.

Abstract:The rheological and gelling properties of a novel biopolymer Ss have been investigated. Like Xanthan Gum, this polymer was distinguished by its high viscosity, pseudoplasticity and salt-tolerance. 0.6%(W/V) Ss concentration transformed to gel by heating (≥75℃) and then cooling to room temperature. Adding metal ions changed the critical concentration of gelling as well as the textural characters of the gel forming. The effects of different polymer and calcium ion concentrations on the textural properties were examined using instrumental Texture Profile Analysis (TPA). Adding calcium ions enhanced sol-gel transition. Hardness, springiness and cohesiveness increased with increasing polymer and calcium ion concentration, but decreased when surpassed a critical calcium ion concentration.

Abstract:Biodegradability evaluation for caster oil-based lube oil was carried out in the test. By repeated experiments, a basic analytical method for degradability of the lube oil was established and compared with the routine experimental method. The results showed that the basic analytical method was more logical and more reliable, and the experimental data have higher repeatability than the previous ones. Under the optimal culture conditions for the targeting strains 5-11-4, and according to the basic method, the degradation rate of the lube oil arrived to 88.37%, approximate 10.25 percent higher than the corresponding yield obtained by the routine experimental method (the value was about 78.12%), indicating the difference between the basic analytical method and the routine experimental one.

Abstract:The effect on the growth and phenol degradation of the thermophilic strain BF80 by seventeen different metal ions were studied. The results showed that the metal ions certainly affected the growth and phenol degradation of the strain BF80. At the concentration of 0.01%, contrasting to the comparison, the growth and phenol degradation of the strain BF80 were restrained intensively by the metal ions of Cu2+, Zn2+, Co2+, Ba2+, Hg2+, Ni2+, Ag+, Al3+. The metal ions of Cr2+ restrained the phenol degradation of BF80 strongly while Cr2+ restrained the growth of BF80 faintly. The metal ions of Sn2+, Fe2+, Fe3+, Pn2+ restrained the growth and phenol degradation of the strain BF80 at a certain concentration, and the effect of inhibition increased with the increase of the concentrations of the metal ions. At the low concentration of Mn2+ or Mo2+, the growth and phenol degradation of the strain BF80 were increased, but if the concentration beyond the 0.1%, the growth and phenol degradation of the strain BF80 were inhibited. At the different concentration of Ca2+ or Mg2+, the growth of the strain BF80 were increased and the phenol degradation were accelerated, but the max rate of phenol degradation by BF80 was not influenced obviously. When the medium was added the mixture of metal ions of Mo2+ and Mn2+, the strain BF80 grew better, but the rate of the phenol degradation was lower than that of single Mo2+ and Mn2+.

Abstract:Effects of Pb, Zn, Cu and Cd on growth and enzyme activities of microorganisms such as Bacillus licheniformis 2709, Bacillus subtilis1.398 and Aspergillus usamii 537, which can individually produce alkaline, neutral and acid protease, were studied, respectively. By determining growth and enzyme activities of three bacterial species, as well as analyzing their tolerance and resistance indicators (MTC and MIC) using growth inhibition plate analysis (GIPA) under different heavy metal gradients, results showed that four heavy metals under higher than a special concentration level significantly inhibited growth and enzyme activities of three species. The alkaline protease exhibited greatest adaptability to four heavy metals, next the neutral protease also exhibited certain adaptibilty to Zn and Cd, whereas the acid protease was totally inhibited under any levels of heavy metal concentrations. Three species not only showed great potential to tolerate and resist toxicity of lead and zinc (2.0 mmol/L-6.0 mmol/L), but also showed certain resistance to cadmium (0.5 mmol/L-0.75 mmol/L).

Abstract:Erwinia carotovora subsp. betavasculorum (Ecb) strain EcbCSL101 produces high levels of extracellular enzymes including pectate lyase (Pel), polygalacturonase (Peh), protease (Prt) and cellulase (Cel) and elicits hypersensitive response (HR) in tobacco leaves. Southern blot analysis using Ecc strain CSDS001 hrpN DNA as probe revealed that EcbCSL101 possesses hrpN gene. A DNA fragment containing entire ORF of EcbCSL101 hrpN was PCR amplified and cloned into vector pET28a(+). Nucleotide sequence analysis reveals that EcbCSL101 hrpN possesses a 1113 bp ORF which encodes a 36.65 kD HarpinEcbCSL101 protein. The deduced amino acid sequence of EcbCSL101 hrpN shares high homology with Harpin proteins of several other Erwinia carotovora strains (GenBank number DQ355519). HarpinEcbCSL101 protein was expressed in E. coli strain JM109 (DE3) by IPTG induction. The purified HarpinEcbCSL101 effectively elicits the HR in tobacco leaves.

Abstract:To obtain a number of penicillinases and degrade penicillin in milk by using the penicillinases, the gene encoding penicillinase was amplified by PCR from Bacillus cereus ATCC10987, cloned into pET28a(+), transformed into E. coli BL21; analysis of SDS-PAGE and penicillinase activity of the recombinant protein were done under induction of IPTG and the result showed that the maximum penicillinase activity reached 480 U/mL; the purity of penicillinase purified by Ni2+ Purification System was more than 90%; the immobilized penicillinases were obtained by sodium periodate method and the residual quantity of penicillin in milk(containing 0.5 U penicillin G/mL) was less than 4 ppb after degraded by the immobilized penicillinase.

Abstract:On the basis of morphological, physiological and biochemical characterization, the antagonistic bacterium strain L1 against Phyricularia grisea was identified. The strain L1 was bacilliform, Gram-positive, fuscous and draped colonies, aerobiosis. The result showed that the strain L1 belongs to Bacillus subtilis. The antimicrobial activity of fermentation liquid reached the highest after 5 days-old cultures. And inhibitory rate accounted for 74.57%, but it had not changed along with the time increase. The activity effect of antimicrobial substances was insensitive to heat. The filtrated Bacillus subtilis strain L1 was precipitated in grades with the ammonium sulfate to draw the antimicrobial proteins and crude proteins were obtained. One crude protein drawn with ammonium sulfate at 50%~60% saturation showed strong antimicrobial activities to Phyricularia grisea. Average radius was accounted for 0.51 cm.

Abstract:Bacillus are well known antibiotic producers. In this study, dozens of Bacillus strains from different sources were screened. Among them, a strain with strong antifungal activity was found. With 16S rDNA test and Biolog assay, this strain was identified to be Bacillus amyloliquefaciens. The fermentation conditions were optimized in small conical flasks. After ammonium sulfate salting out, dialysis, freezing vacuum dehydration, the crude protein extracts were obtained. The thermal stability, pH stability, protease stability, ion stability and antifungal spectrum of this protein were studied further. Scanning electronic microscope was also used to explore the antifungal mechanism.

Abstract:The symbiotic seed germination of Pleione bulbocodioides (Franch.) Rolfe, a traditional Chinese medicine, was investigated. The results showed that the mycorrhizal fungi isolated from pleione bulbocodioides, GN21, GN23 and GN24 promoted the seed germination evidently, and the germination rate of GN21 was up to 84.6%, much better than the others and control. However, the fungal species isolated from the same species of orchid, even if belonging to the same genus, could not be always to stimulate the seed germination, some species even became pathogens under the circumstances of poor nutrition.

Abstract:Inhibitory effect of purple sweet potato pigments (PSPPs) on E. coli, Staph. aureus, Sacc. cerevisiae and Asp. niger was investigated in this paper. The results showed that E. coli and Staph. aureus could be inhibited strongly by PSPPs and dependent on the concentration of PSPPs, but no inhibitive effect of PSPPs on Sacc.cerevisiae and Asp. niger was observed. Observation under Transmission Electron Microscope was carried out and growth curve of E. coli was ploted out. It was indicated that PSPPs might change the permeability of cell membrane, make cell excrescent and inhibit cell division. As a result, cytoplasm could become thin, disassembled and even die. SDS-PAGE analysis suggested that PSPA have some influence on some proteins synthesis, but no disappearance of special protein lines be found.

Abstract:In this paper, two selective media—TCBS agar and CHROMager—were utilized for the isolation of Vibrio parahaemolyticus (Vp). According to the biochemical identification, all the 27 suspected strains which were isolated from 60 samples of seafood were identified to be Vp, 22 strains of them were from fresh seafoods and 5 strains were from frozen ones. With further research on 4 special biochemical tests, comparing these 27 Vp strains with 32 Vp clinic strains isolated from patients, there were some difference in Hemolysis test, Urease test and Citrate test, while no significant difference in Arabinose test. As such, it supplies a theoretic basis for studying in biochemical characteristics of Vp from different sources.

Abstract:The fermentative H2-producing strain Clostridium sp. H-61 was isolated from anaerobic sludge, was used as an original strain which was induced by NTG and UV for increasing and the hydrogen production ability. One of the highest efficient H2-producing mutants was named as HCM-23 with its stable hydrogen production ability. which was measured in the batch culture experiments. With the condition of 10 g/L glucose, its cumulative hydrogen yield and hydrogen production rate was 3024 mL/L and 33.19 mmol H2/g DW·h, 69.89% and 68.14% higher than that of the original strain, respectively. The terminal liquid product compositions showed that the mutant HCM-23 fermentation was ethanol type, while the original strain H-61 fermentation was butyric acid type. Varieties of parameters of hydrogen production fermentation studied, including time, carbon source, nitrogen source, glucose concentration, glucose utilization, initial pH and incubation temperature had been studied, indicated the optimum condition of hydrogen production for the mutant HCM-23 as initial pH 6.5, temperature 36℃, and the favorite substrate was sucrose. The hydrogen production characters of the mutant and the original strain were different, such as, the growth lag phase and the utilization of inorganic nitrogen source, etc. This work shows a good application potential of NTG-UV combined mutation in the biohydrogen production. And the hydrogen production mechanism and metabolic pathway should be explored furthermore.

Abstract:To improve the antibiotics production of Streptomyces qinlingensis sp. nov., protoplast regeneration combined with physical and chemical mutagenesis was used to selected high-yielding strains. The results showed that the antibacterial activities of strain R-72 from protoplast regeneration and NTG-1, H30-7 from protoplast mutagenesis against Bacillus subtilis were more than 20% higher than that of the original strain, and the heredity characters of those strains were stable in successive ten generations. The further bioassay experiments exhibited that the fungicidal and antibacterial activities of the fermentation broth from R-72, NTG-1 and H30-7 were remarkable increased comparing with that of the starting strain.

Abstract:Strain QJ16, one of some methanotrophic bacteria isolated from soil samples utilizing the separate device designed by our laboratory; was studied in detail and identified as one of the Genus methylomonas through 16S rDNA sequencing and comparison. The culturing and reaction conditions for methane utilization of this strain were investigated. The results indicated that the optimal conditions for the growth of strain QJ16 were methane gas as carbon source and the coexistence of NH4Cl and KNO3 as nitrogen source, the cultivation temperature of 30℃ and medium initial pH 6~7, and the optimal Cu2+ concentration of 15 mmol/L.

Abstract:Activated sludge is a complicated microbial ecosystem that has diversity. Based on the diversity, microorganisms are selected by acclimation condition: the survival of the fittest, otherwise eliminate through selection or contest. Moreover, microorganisms in activated sludge acclimatize themselves to acclimation conditions. In the process the ecosystem distributes and adjusts microbial niche over again. The theory of “selection and acclimatization” may be used to explain the mechanism of activated sludge acclimation. So then, original sludge, wastewater quality and treating process are major influencing factors for activated sludge acclimation.

Abstract:Streptococcus gordonii is a nonpathogenic gram-positive commensal bacterium and component of the normal microbial flora of the human oral cavity. It is suitable to be as a mucosa vaccine vector due to its special bionomics. knowing the bionomics of Streptococcus gordonii , the general expressing system , and the application of it in mucosa vaccine, will provid important reference for the further development of its mucosa vaccine.

Abstract:Chlorobenzenes are main pollutants in wastewater. The new development of the microbial treatment techniques for chlorobenzenes-removal in the wastewater is discussed in this paper. It was included that microoganisms degrading chlorobenzenes, aerobic and anaerobic biodegradation, biological co-meta- bolism, and biological treatment processes. The developmental trend of biological degradation chlorobenzenes is also predicted.

Abstract:Many microbial pathogens, including those responsible for major enteric infections, exploit oligosaccharides that are displayed on the surface of host cells as receptors for toxins and adhesins. Blocking crucial ligand receptor interactions is therefore a promising therapeutic strategy. One approach is to express molecular mimics of host receptors on the surface of harmless recombinant bacteria that can survive in the gut. These recombinant probiotics bind bacterial toxins in the gut lumen with very high avidity, thereby preventing disease.

Abstract:The preservation of culture is the base of microbiology research and correlative specialty. Freeze-drying is one of the most effective methods. Many researches have been performed to improve the effect of freeze-drying method. The paper mainly describes the principle and advantage of freeze-drying. In addition, the paper introduces the influencing factors to freeze-drying method.

Abstract:It is important to pay more attention to students’ basic skills training and their comprehensive abilities cultivating in microbiology experiment teaching. Explorations and reforms in enforcing the students’ base and cultivating their abilities were carried out in order to improve teaching quality and train specialized talents with high quality.

Abstract:Based on the data of the ISI “Journal Citation Report” in 2006 edition, a statistics for the 88 microbiology science journals has been made. The results showed that these 88 learned journals were published in 16 countries with 3 languages, especially English. And the main countries were United States, England, Netherlands and Japan. The average data of articles and total cites of the 88 journals were 165 and 5226.64, respectively. Moreover, the average data of impact factor and immediacy factor were 3.154, 0.45 and 5.84, respectively. Finally, fifty-five learned journals with impact factor over 2.0 were introduced from these journals to be referenced.

Abstract:The traditional microbiology experimental teaching method and content can not meet the needs of training talented person. Therefore, studying from the experimental contents, experimental teaching pattern and the ways of checking the students’work and taking reforming are done, making microbiology experimental as a separating course and adding comprehensive experiment. The result shows the new experimental teaching pattern contributes to the cultivation of the students’abilities of performing experiment, the ways of thinking, creativity and comprehensive analysis. It’s better than the traditional microbiology experimental teaching.

Abstract:The authors helpfully discuss the design idea, experimental module design, examination methods, and experiment textbook construction in experimental teaching of microbiology, and conduct further researches on the basic skill training, verifying experiment, integrative experiment, and investigative experiment in the course. This study aims to enhance effects of the experimental teaching, to cultivate high potential talents who can master essential knowledge and skills, and creatively carry out scientific research.

Abstract:This paper summarize the practice in the teaching reform of microbiology experiment in recent years. We identify the main contents of experimental teaching systems and pay much more attention to people-oriented. Through the reform of teaching and assessment methods, students are trained to cultivate their practical ability and spirit of innovation.

Abstract:From the facts and specific examples in students’ daily life, the paper here attempts to justify the teaching aid with multimedia and interesting things that can stimulate students’ interest and initiative, help to improve teaching effect and quality by making microbiology as concrete and interesting as possible.

Abstract:Four primers against the genes encoding (cpa, cpb, etx, and iA) four major toxins(α, β, ε, ι) of Cl. perfringens were designed and the colony multiplex PCR of identification and genotyping of Cl. perfringens strains were developed. Cl. perfringens reference strains stored in china institute of veterinary drug control including A, B, C, D and E genotyping were genotyped using the colony muitiplex PCR assay. The expected sequences were obtained successfully by the colony multiplex PCR assay. But the sequences were not obtained from Cl. novyi, Cl. septicum and Cl. tetani. The expected sequences were obtained from Cl. perfringens individual colony diluted to 100 times with 0.85% saline solution.13 Cl. perfringens strains isolated from diferent animals were genotyped using the colony multiplex PCR assay, and the results were comparaed with the results of toxins neutranization test in mice. The two assays showed good accordance. These results showed that the development of the colony multiplex PCR is very important for early and fast identification and genotyping of Cl. perfringens in china.