Abstract:

Abstract:Rhodopseudomonas palustris (R. palustris) is a common type of purple phototrophic bacteria found in a wide variety of environments. As a result of the diverse metabolism mechanisms, they are ecologically important and have valuable applications. In this study, we collected eleven sediment samples from lakes, ponds and streams. Samples were cultivated for purple nonsulfur bacteria enrichment. With PCR-DGGE based on pufM gene fraction, the enriched bacteria were phylogenetically identified as R. palustris. Genotypes from these bacteria were differentiated with rep-PCR for cluster analysis. We found that R. palustris from similar habitats, eg. lakes, can be categorized into a group with > 80% fingerprinting similarity. On the contrary, the genotypes of R. palustris from distinct habitats are distant. Our results suggest a relationship between the genotype diversity of R. palustris and their habitat variances. This finding allows a foundation for further studies on the ecological importance and evolution pathway of such purple nonsulfur bacteria.

Abstract:

Abstract:Biodiesel, as a new form of bio-fuel, has developed greatly in recent years. The second generation of bio-energy represented by the lipid from microalgae is one of the long-term strategies to solve energy crisis in the future. However, improving its productivity is still the hotpot in recent years. The aim of this work was to improve the biomass and lipid content of autotrophic microalgae. In this study, we used uniform design to optimize the major culture conditions of autotrophic microalgae in the air-lift bioreactor. The significant regression equations which showed the effects of these conditions on biomass and lipid content of Chlorella C2 were concluded, respectively. According to the significant regression equations, the optimized culture conditions of biomass were: 0.178 g/L the concentration of N5+, 5 L/min air rate, 3% (V/V) CO2 and 6000 lx light intensity. The biomass and productivity attained were 2.11 g/L and 0.352 g/(L·d), 12.2% higher than the highest biomass and productivity obtained [1.88 g/L and 0.313 g/(L·d)] in those experiments. The optimized culture conditions of lipid content were: 0.400 L/min air rate and 1.94% (V/V) CO2. Lipid content attained from the optimized culture condition was 22.4%, 7.7% higher than the highest lipid content (20.7%) obtained in those experiments.

Abstract:An experiment on the effect of carbon source, nitrogen source, metal ion and salinity on degradation of aniline blue dye by Mucoromycotina sp. HS-3 was carried out under statically air-opened condition. The results showed that the optimum medium for single factor were 1 g/L glucose, 0.6 g/L ammonium sulfate, 0.15 mmol/L Fe3+, and less than 50 g/L salinity, respectively. Under each optimum condition above, the decolorization rate of aniline blue dye (100 mg/L initial concentration) was over 95% after 5 days. In addition, a toxicity test was carried out using a bioassay based on growth inhibition of Vigna unguiculata (a plant species) and Bacillus subtilis (a bacterial species) by aniline blue solution before and after degradation. The result showed that the toxicity of aniline blue after degradation had reduced obviously. So this strain had a good application potential for treating dyeing wastewater mainly consisted of aniline blue.

Abstract:We isolated and purified a Microcystis strain, Chaohu-1, from Chaohu Lake by the method of plate streaking and liquid culture. After the successive steps of methanol extraction and solid-phase ex-traction, it was confirmed that the algae strain produces MC-LR as analyzed by HPLC. The algae cells were green and spherical, while the population displayed a random reticulate form. The phycocyanin intergenic spacer region (PC-IGS) was amplified by whole-cell PCR, cloned and sequenced. The PC-IGS sequence showed a degree of similarity of 99% with those of Microcystic aeruginosa strains downloaded from GenBank. A combination of the analysis results both at morphological and molecular levels indicated that for the first time we have isolated a Microcystis aeruginosa strain in Chaohu Lake, and we named it Chaohu-1. Moreover, we established an effective method for its cryopreservation and cell resuscitation, which laid foundation for the long-term preservation and the future research.

Abstract:In Saccharomyces cerevisiae, mitochondria NAD(H) kinase Pos5p has significant function. Absence of POS5 gene leads to antioxidative dysfunction. In order to realize the mechanism of anti-oxidative function of Pos5p and its relation to the conversion of coenzyme NAD(H) to NADP(H), we compared the growth phenotypes of wild-type BY4742, POS5 gene deletion mutant pos5Δ and pos5Δ containing POS5-YEplac195 plasmid (pos5Δ/POS5-YEp) under exposure to different kinds of oxidative reagents, and assayed their intracellular coenzyme concentration by the high performance liquid chromatography (HPLC). The results showed that only the pos5Δ had obvious growth defect under all of the three oxidative reagents, that is, superoxide anion generation reagent menadione (VK3), hydrogen peroxide (H2O2) and GSH consumption reagent diethyl maleate (DEM), while the tested anti-oxidative gene deletion mutants only had growth defect under their corresponding oxidative stress. In the normal growth condition, NADPH content of pos5Δ reduced, while that of pos5Δ/POS5-YEp increased, indicating that Pos5p play an important role on the supply of NADPH. Under the exposure to VK3, H2O2 and DEM, the NADP(H) concentration of BY4742, pos5Δ and pos5Δ/POS5-YEp all reduced, with the ratio of NADP(H) to NAD(H) in pos5Δ decreased most obviously. The research indicated that under different kinds of oxidative stress, Pos5p could exert NAD(H) kinase activity effectively to supply NADP(H) and thus had an important antioxidative defense funtion.

Abstract:To construct the mutant strain Δsao, the recombinant gene knock-out vector was constructed consisting of Spcr cassette with the flanking homology regions of gene sao. The sao gene was replaced by Spcr cassette according to the principle of homologous recombination. PCR analysis, RT-PCR analysis and western blot were used to confirm that sao gene was replaced completely by the Spcr cassette. The results suggested that the mutant of 05ZYH33 sao gene was successfully constructed. Analysis of biological characteristics showed that there were no obvious distinctions in hemolytic activity, growth characteristics and virulence between the mutant and the wild type strain 05ZYH33. The construction of the mutant strain 05ZYH33Δsao laid the foundation for father research on the role of sao during infection.

Abstract:YD4-6 and NV11-4 strains were isolated from wheat soil and vegetable soil, both of them exhibited a better antifungal activities to several plant pathogens. The results exhibited that YD4-6 and NV11-4 showed antifungal activities to Rhizoctonia solani, Magnaporthe grisease, Sclerotinia sclerotiorum and Alternaria brassicae, while NV11-4 also can inhibit the growth of Fusarium moniliforme. Both of these two isolates exhibited without chitinase activity, NV11-4 with cellulase activities. Based on these differences to antifungal and cellulase activities of the YD4-6 and NV11-4, their effects on rice defense enzyme were observed. The results indicated that YD4-6 and NV11-4 effectively increased rice PPO, POD, PAL and SOD activities, also promoted concentration of MDA. When the R. solani used with isolates YD4-6, NV11-4, respectively, the induced activities of PPO, POD, PAL, SOD and concentration of MDA were higher than that of only used R. solani, YD4-6 or NV11-4. Compared with two antagonistic bacteria induced activities to rice defense enzyme, NV11-4 exhibited more durable than that of YD4-6, also YD4-6 induced accumulation of MDA, these difference maybe related with character of these two isolates. These two isolates were identified in database by using 16S rRNA sequence of YD4-6 or NV11-4. YD4-6 identified as Bacillus cerecus, and NV11-4 as Bacillus subtilis.

Abstract:Using real-time PCR method to detect the effects of varying levels of triticale dried distillers grains with solubles (TDDGS) inclusion in beef cattle diets on the populations of three rumen Prevotella species viz., Prevotella ruminicola, Prevotella brevis and Prevotella bryantii. The results showed that 1) compared with control group (CG), the populations of P. ruminicola and P. brevis in all TDDGS groups (20%, 25% and 30% TDDGS) increased, and a 47-fold (P < 0.05) and a 794-fold (P < 0.05) significant increase were observed in 20% TDDGS group respectively, however, the population of P. bryantii decreased in all TDDGS groups and a 5-fold (P < 0.05) significant decrease was found in 20% TDDGS group; 2) compared among TDDGS groups, significant population difference was only observed between 20% and 30% TDDGS groups for P. ruminicola, however, no other significant population differences were found between the TDDGS groups for the three Prevotella species. The conclusion was that incorporation of 20% TDDGS in beef cattle diet significantly affected the populations of all three rumen Prevotella species but no obvious population changes were found between the TDDGS groups.

Abstract:Eighty six bacterium isolates were obtained from rhizosphere of ginger. Through antagonistic tests, two antagonistic strains against Pythium myriotylum Drechsler were isolated, which were designated as JF24 and JF3, respectively. Based on the morphological, physiological and biochemical characteristics and phylogenetic analysis of 16S rRNA, JF24 and JF3 were identified as Pseudomonas fluorescens and Alcaligenes faecalis, respectively. The sequences of 16S rRNA of them have been submitted to GenBank and the accession numbers are FJ999730 and FJ999731, respectively.

Abstract:The most of secreted proteins are exported by Sec translocase (Secretion pathway). SecA ATPase is the preprotein translocase nanomotor that undergoes membrane insertion and deinsertion to drive preprotein across the bacterial inner membrane, which is unique and indispensable to bacteria. It should be presumed that the compound which inhibits the activity of SecA ATPase probably can be used as the candidate of bactericide. Pseudomonas aeruginosa secA gene product, whose amino acid sequence displays PaSecAN75 (The N-terminal first 645 amino acids of Pseudomonas aeruginosa SecA), was cloned, overexpressed and purified in order to establish enzyme inhibitor screening model. After establishment and optimization of screening assay, a primary screening was performed with compounds library and microbial fermentation collection in our institute. 4 out of 3220 compouds and 66 out of 7196 microbial fermentation samples were identified as primary hit. To confirm the hits from the primary screening, a cell-based SecA activity assay was used to assess their inhibitory effect in vivo. Results showed that 3 compounds and 6 microbial fermentation samples inhibited enzymic activity of SecA in vitro and impaired its function in vivo.

Abstract:Various samples of Douchi, a kind of traditional Chinese fermented soybean food, were collected from provinces of China. Different strains with fibrinolytic activity were screened from these samples by enrichment culture medium and fibrin plate was used to confirm their fibrinolytic activity. Thirteen distinct strains were identified as Bacillus sp., Streptomyces sp., Pseudomonas sp. and Arthrobacter sp. by classical classification approaches, chemical approaches and 16S rDNA sequencing. Nine Dou chi fibrinolytic enzyme-producing strains were gained.

Abstract:To approach the relationship between the srtF gene and the high pathogenicity of S. suis 2 05ZYH33, an isogenic knockout mutant of srtF was generated based on the principle of homologous recombination and confirmed by PCR, restriction analysis and reverse transcription polymerase chain reaction. The resulting mutant strain exhibited growth kinetics equivalent to those of the WT parent strain upon cultivation in standard laboratory used in our in vitro assays. A similar absence of difference between parent strain and mutant was observed when competition infection mice by the WT and mutant strains was evaluated. Taken together, these results suggest that srtF might in fact not critical for the full virulence of S. suis 2. It is to expect that future study carried out with S. suis 2 to verification the conclusions.

Abstract:We evaluated immune protection effectiveness of the aeromonas hydrophila emusion-oil vaccine in an immergence challenge model against haemorrhagic intestinal necrosis (HIN) and red abdominal shell by using soft-shelled turtles. In the active immune protection test, a high level of antibody was produced by the vaccine group. All the soft-shelled turtles in the vaccine group (10/10) were survived after challenged with 10 times 50% lethal dose (LD50) of virulent T3 strain, compared with 30% (3/10) survivors in the control group injected with 0.8% NaCl solution. In the passive immune protection test, 80% survivors (8/10) were observed in the group injected with serum, but only 20% (2/10) survivors were observed in the control group injected with 0.8% NaCl solution. These results showed that hydrophila Aeromonas emusion-oil vaccine had good immunogenicity, which could be used in the prevention of haemorrhagic intestinal necrosis (HIN) and red abdominal shell in soft-shelled turtles.

Abstract:The use of Rhodopseudomonas palustris in biosynthesis of silver nanoparticles (AgNPs) emerges as a reliable and eco-friendly approach in recent years. This report focuses on extracellular biosynthesis of AgNPs using cell filtrate of Rhodopseudomonas palustris. These nanoparticles were characterized by UV-vis spectrum, X-ray diffraction (XRD) spectrum and transmission electron microscopy (TEM). UV-vis spectrum of the aqueous medium containing silver ion showed a peak between 420 nm?460 nm corresponding to the plasmon absorbance of AgNPs. TEM micrograph showed formation of the AgNPs in the range of 5 nm?20 nm. XRD of the nanoparticles confirmed the formation of metallic silver. The AgNPs were evaluated for their antimicrobial activities against Escherichia coli and Staphyloccocus aureus.

Abstract:To identify the 16S?23S rRNA gene in Klebsiella pneumoniae, a PCR-DHPLC assay was performed in this study. Primers specific for the 16S?23S rRNA gene of Klebsiella pneumoniae in diary were selected to conduct the DHPLC assays. The specific testing was performed with Klebsiella pneumoniae and 57 strains, and various grads of Klebsiella pneumoniae was used for the sensitivity testing. The good specificity was found in this study. Also, the method showed nice sensitivity with the lowest amount of detecting at 100 CFU/mL, so it can detect and identify Klebsiella pneumoniae quickly and correctly. The DHPLC could be a new method for detecting diary pathogens.

Abstract:The actinobacteria have been detected in guts of many animals including insects by molecular methods. Finding novel actinobacterial species, screening novel natural products, reevaluation of coevolution between attine ants and actinomycete bacteria, and eliminating the parasites of disease vectors have been done based on the studies on animal symbiotic actinobacteria. The present results for terrestrial animal symbiotic actinobacteria were reviewed and the perspectives were outlined.

Abstract:Production practice is an important component in practice teaching of bioengineering. There were many problems in practice teaching such as short of funds, few collaborated enterprise and poor operating opportunity for students. Aiming at these main problems, production practice teaching was reformed through computer simulating, factory training and machine workshop developing in Yantai University, the practice effect of bioengineering in Yantai University was improved as well as students’ practical ability and overall quality.

Abstract:T-RFLP is a newly developed molecular technique for microbial diversity analysis. Compared with other techniques, T-RFLP has several unparalleled advantages. However, there is no report on measuring the system errors generated in T-RFLP operational process. In this study, diversity analysis of nifH gene from 4 soil samples which represented different invaded stages after Ageratina adenophora (Sprengel) invasion was chosen as a case. In order to determine possible system errors in our study, multiple analysis in which only one procedure of the whole operational processes was changed each time were conducted. Results showed that repeatability for the results of T-RFLP analysis was influenced mostly by the types of Restriction Endonucleases, followed by the PCR procedure, while capillary electrophoresis has almost no effect.

Abstract:Real-time quantitative PCR is a commonly used method to analyse the gene expression profile, it is important to select an appropriate reference gene for normalization of experimental data when using this method. In our study, we used two statistical methods to evaluate the gene expression stabilities of five reference genes (ldh, recA, rpoB, gapdh and 16S rRNA) under the different growth phases of Lactobacillus helveticus H9. The results showed that the best reference gene was ldh which was the most stable gene would be used for normalization of real-time quantitative PCR experiments data.

Abstract:Efficient storage of the wild germplasm is prerequisite for conservation and utilization of Termitomyces. In our study, using 5 isolated Termitomyces strains as materials, the preservation effects of distilled water preservation method and ?80°C freezing storage method were compared. These five wild strains of Termitomyces were stored in distilled water at room temperature and 4°C refrigerator, as well as preserved at ?80°C freezer for about 20 months after programmable cooler and styrofoam box controlled cooling. The survival rates of strains in distilled water were 100% after 20 months storage at room temperature, and that for frozen at ?80°C were 56%?76%. The strains preserved in distilled water at room temperature germinated in 4 to 10 d after inoculation, which is quicker than in ?80°C preservation (7?16 d). Styrofoam box method is an easy and effective method to control cooling speed compared to the programming method. In summary, preserving strains in distilled water at room temperature is a simple, practical and cheap method for long-term storage of Termitomyces germplasm.