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Abstract:A DPPH-microplate assay was employed for quantitative analysis of the free radical scavenging activity of the extracts extracted with different solvents from mycelia of Isaria gracilioides. The results showed that the methanol extract had the strongest free radical scavenging activity. At the concentration of 10 mg mycelium per milliliter methanol, the radical scavenging rate of the extract reached 92.4%±0.3%. The results of DPPH-TLC assays showed that the methanol extract contained four main free radical scavenging components. The combined LC-DAD-HRMS and DPPH assay revealed that the molecular formulas of the four free radical scavengers were possibly C15H16NO3 (1), C32H40N2O18 (2), C30H55N5O5 (3) and C17H14N2O2 (4). Natural products database query showed that compounds 3 and 4 were possibly viscumamide and dehydrocyclopeptin, respectively, and compounds 1 and 2 were novel molecules. Viscumamide and dehydrocyclopeptin were detected from entomogenous fungi for the first time.

Abstract:

Abstract:3-HPA was a toxic intermediate metabolite in the 1,3-PD pathway of Klebsiella pneumoniae and its accumulation could inhibit cell growth and glycerol utilization. In order to reduce the 3-HPA accumulation and produce 3-HP simultaneously, the aldh gene from a Saccharomyces cerevisiae en-coding NAD+-dependent acetaldehyde dehydrogenase (ALDH) was cloned and the expression vector pKP-aldh harboring aldh gene was constructed and transformed into K. pneumoniae. The resulting re-combinant strain K. pneumoniae A+ could express the ALDH effectively. The bacteria was mutated by UV lights and screened in 3-HP tolerance plates to yield K. pneumoniae A+5-3. In the fed-batch fermenta-tion of K. pneumoniae A+5-3, the final 3-HP and 1,3-PD concentration reached 5.0 g/L and 74.5 g/L, re-spectively, which were higher than those of wild-type K. pneumoniae.

Abstract:The bacterial diversity and phylogenetic analysis of two hot springs in Chengde were investigated and analyzed by construction of 16S rRNA gene clone libraries. The results showed that bacteria in sample A11 (68 °C) could be divided into 5 groups, which were as follows: Firmicutes (6.25%), Deinococcus-Thermus (25.0%), Gammaproteobacteria (12.5%), Betaproteo-bacteria (50.0%), Al-phaproteobacteria (6.25%). But sample A12 (74.5 °C) contains only one group, Firmicutes. The differ-ence between the two samples revealed that the temperature was an important factor to affect the level of bacterial diversity in hot springs. Furthermore, a lot of 16S rDNA sequences in A11 clone library had high similarity to the aerobic bacteria that can produce pigment, while most bacteria in A12 clone li-brary belonged to obligate or facultative anaerobe, in which, Anoxybacillus flavithermus can be used as ideal material to research the formation of sinter.

Abstract:In this paper, two newly isolated bacterial strain A1 and strain A2, which were capable of degrading formaldehyde in high efficiency, were identified based on the results of standard morphological identification, physiological and biochemical characters, 16S rDNA sequence analysis. Their capability of degrading formaldehyde was investigated by determination of the formaldehyde concentration change in culture. The biological packed tower hung membrane experiment was carried to determine the purification performance of the two bacterial to formaldehyde gas. The results showed that: these two bacterial strain A1 and strain A2 were identified as Pseudomonas and Sphingomonas, respectively; when formaldehyde initial concentration was below 1 200 mg/L, it could be degraded by bacteria strain A1and strain A2 completely; when original formaldehyde concentration was up to 1 600 mg/L, 50% of formaldehyde was consumed by strain A1 after 48 h, 74.3% of formaldehyde was consumed by strain A2 after 104 h; the removal efficiency of these two bacteria could be over 99%, the formaldehyde re-moval biochemical can amount to 26.4 mg/(L?h) of strain A1 and 20.6 mg/(L?h) of strain A2.

Abstract:The distribution of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) and the potentials of ammonia and nitrite (NO2?) oxidation were studied in the sediments of Xihu Lake in Quanzhou. The high concentrations of organic matter (OM), total nitrogen (TN) and ammonia existed in the sediments of Xihu Lake. The number of AOB were 1.1×106?6.4×106 cells per g of dry sediment which were higher than 4.2×105?7.4×105 cells per g of dry sediment of NOB (Paired t-test, P<0.05). With regard to NOB, the two genera of Nitrobacter and Nitrospira coexisted in the sediments of Xihu Lake, and Nitrobacter were the dominant NOB. The difference of AOB and NOB number resulted to some extent in that ammonia oxidation potentials were significantly higher than NO2? oxidation poten-tials (Paired t-test, P<0.05), indicating that NO2? oxidation was the rate-limiting step in nitrification. In addition, the high ammonia concentrations in sediment of Xihu Lake which accelerated ammonia oxi-dation but selectively inhibited NO2? oxidation, also lead to low NO2? oxidation potentials.

Abstract:To develop a effective controlling method against Vibrio parahaemolyticus, we isolated a lytic phage qdvp001 from aquatic sewage water. Phage qdbp001 was isolated by double-layer plate method and its morphology character were observed by transmission electron microscopic. Furthermore some physiological properties such pH stability, thermal stability, multiplicity of infection (MOI) and one step curve were also reported. Deoxyribose nucleic acid (DNA) from phage qdbp001 was digested with the restriction endonuclease and then analyzed the sequence. Phage qdvp001 with a head diameter of about 79 nm and a tail size of about 102 nm belongs to the family Myoviridae. It has a strong endurance of temperature below 60 °C, its optimum pH value and MOI were about 7.0?8.0 and 0.000 1 re-spectively. The phage growth cycle with a detected latent period of 20 min with lytic period of 10 min. Six DNA sequences were obtained and showed low homology with others when compared with those reported information in NCBI. Phage qdvp001 might be a novel bacteriophage.

Abstract:According to the sequence of sikSAD gene from GenBank, we cloned sikSAD gene from Sasussured involucrata Kar. et Kir though RT-PCR, and constructed the recombinant E. coli/Yeast shuttle vector pYES2-sikSAD. Then it was transformed into S288C yeast by electroportion method, PCR and SDS-PAGE analysis indicated that sikSAD had been integrated into the genome. That the recombinant vector had been transformed into yeast. Finally, we made preliminary analysis on the resistance and analysis of variance under low temperature stress and ethanol tolerance. The results suggest that the recombinant yeast pYES2-sikSAD can not only survive in low temperature but also grow well at 28 °C in the experiment of low temperature stress, the percentage of oleic acid have obvious change. In the experiment of ethanol tolerance, the recombinant yeast pYES2-sikSAD can tolerant certain concentra-tion of ethanol, also the ability of tolerance increased more than 10 percentage compared with non-transformed yeast. The above testify that the recombinant yeast pYES2-sikSAD have more toler-ance and excellent activity and growth advantage under the low temperature and high ethanol. This ex-periment using molecular technology to reconstruct yeast which can provide the basement for producing Saccharomyces cerevisiae with higher quality in industry.

Abstract:Saccharomyces cerevisiae cDNA express library of Paecilomyces sp. FLH30 was constructed by re-construction of the vector pYES2-GSL, and full-length cDNA encoding an endo-β-1,3(4)-glucanase gene (PsBg16A) was screened using Congo red-staining method. The full-length cDNA of PsBg16A is 1 217 bp and has an open reading frame of 951 bp. The PsBg16A encodes a 316-residue precursor protein with a putative signal peptide, and the deduced amino acid sequence of revealed that this enzyme belongs to glycoside hydrolase family 16. PsBg16A without signal peptide was cloned into a vector pET28a(+) and was expressed successfully in E. coli BL21(DE3), and the enzyme activity reached 482 U/mL induced by lactose at 16 °C. The purified recombinant PsBgl6A with optimum pH at 7.0 and optimum temperature at 65 °C, can randomly hydrolyze barely β-glucan, lichenin and laminarin. The results suggested that the enzyme is a typical endo-β-1,3(4)-glucanase (EC 3.2.1.6) with broad substrate specificity for β-glucans, and Km for β-glucan, lichenin and laminarin were 2.92, 4.35 and 9.88 g/L, respectively.

Abstract:The CCCP-treated marine microalga Tetraselmis subcordiformis could photo-produce hydrogen for sevaral days. Effect of photosynthetic inhibitors on hydrogen production helped to draw the network of hydrogen metabolism by CCCP-treated T. subcordiformis: at the beginning of hydrogen production, electrons provided to hydrogenase are mainly from photolysis and photofermentation via PS I and electron chain; thereafter, fermentative hydrogen production is considered as the most responsible for providing electrons to hydrogenase, which is independent of photosystem electron transfer chain. Fermentative metabolites assay indicated that light and DBMIB inhibited fermentative ethanol produc-tion that is the competitive pathway for the cellular reducing power, resulting in higher photo-hydrogen yield.

Abstract:In this study, we analyzed the affect of soil fertility and microorganism on continuous cropping obstacles and these results may provided scientific evidence for mechanism of continuous cropping obstacles. Soil fertility, soil micro flora and microbial physiologic flora from the rhizosphere and bulk soil of strawberry and tomatoes rotation (RST), 4 years continuous tomatoes cropping (CT4) and 10 years continuous tomato cropping (CT10) were analyzed respectively. Several main factors were ana-lyzed by the principal component analysis (PCA). The results showed that the number of micro flora and microbial physiologic flora in rhizosphere were higher than bulk soils, which showed a signifi-cantly rhizosphere effect. The number of bacteria and actinomycetes decreased firstly and then in-creased as continuous cropping years increasing, while the number of fungi showed a linear increase trendency. Compare with RST, the CT4 and CT10 increased by 9.09% and 2.11%, 74.58% and 57.72% in rhizosphere and bulk soils respectively. The number of nitrobacteria and aerobic nitrogen-fixing bacteria decreased as continuous cropping years increasing, while the ammonifying bacteria and aerobic cellulose degrading bacteria increased firstly and then decreased. Solution potassium bacterium, inor-ganic phosphor-bacteria and organic phosphor-bacteria decreased in rhizosphere and bulk soil. Among the three planting systems, RST in the rhizosphere soil is best, follow by CT4 in rhizosphere soil and RST in bulk soil, CT10 in rhizosphere and CT4, CT10 in bulk soils were the worst. Continuous vegeta-ble cropping can cause reduction of the soil quality, the longer the continuous cropping is and the more reduction of soil quality.

Abstract:For studying the pathogenesis of the soybean pathogen Pseudomonas syringae pv. glycinea, two types of homologous genes of III-secreted effectors, named as HopAB1s and HopAF1s respectively, were first cloned from Pseudomonas syringae pv. glycinea by means of inverse PCR (iPCR) method. The ORF of HopAB1s gene contained 1 572 bp, encoding 523 amino acid residues. The ORF of HopAF1s gene contained 855 bp, encoding 283 amino acid residues. The two genes registered in GenBank with accession numbers JF826562 and JF826563. The N-terminus of HopAB1s was sufficient for E3 ubiquitin ligases functional domain. The two effectors were inserted into the binary PVX vector, trans-formed into Agrobactrium tumefaciens GV3101, and the Agrobacterium-mediated transient expression experiments confirmed that two effectors functioned to inhibit the ability of the pro-apoptotic protein Bax inducing PCD in plant. Furthermore, infection experiment results showed that the effectors can promote ability of Phylophthora nicotianae infecting tobacco (Nicotiana benthamiana). Two cloned genes both belong to suppressive effector, our research is lay a foundation for revealed the molecular pathogenesis of Pseudomonas syringae pv. glycinea.

Abstract:To clone, express and characterize the antimicrobial activity of duck AvBD5, reverse transcription polymerase chain reaction (RT-PCR) was used to amplify duck AvBD5 gene from lung of duck in the present study. Furthermore, phylogenetic relationships of the duck AvBD5 with AvBDs from other avian species and some mammalian beta-defensin 5 were analyzed. Sequence analysis showed that the cDNA of duck AvBD5 consisted of 201 bp nucleotides, encoding a polypeptide of 66 amino acids. The β-defensin has six conserved cysteines that form three disulfide bonds in a C1-C5, C2-C4, and C3-C6 conformation. It was demonstrated that duck AvBD5 shared 97% amino acid homology with chicken AvBD5. The cDNA of duck AvBD5 was sub-cloned on pGEX-6p-1 vector to construct recombinant plasmid pGEX-duck AvBD5. The recombinant plasmid was transformed into E. coli BL21 and the bacteria were induced with IPTG. After purification, antibacterial activity of the purified recombinant protein was investigated. In addition, effect of ionic strength on the antibacterial activity, and hemolytic activity of the purified recombinant protein were investigated. It was demonstrated that a 32 kD protein in molecular weight was highly expressed. The purified recombinant duck AvBD5 exhibited extensive antimicrobial activity against 11 strain bacteria, including Gram-positive and Gram-negative investigated. In high salt ions conditions, antibacterial activity of recombinant duck AvBD5 protein was decreased. In addition, the recombinant protein of hemolysis activity was extremely low.

Abstract:Bacteriophage therapy had been considered as an effective way for bacterial infection treatment for a long time. The research was started in the beginning of twenty century, but discontinued in America and Western Europe with the advent of antibiotics. Recently, scientists started to re-evaluate the bacteriophage therapy due to the worldwide bacteria resistance and found the great potential of phage-based prophylaxis and therapy of antibiotic-resistant bacterial infections. This paper reviews the history of bacteriophage therapy and the application in the treatment of human and animal bacterial in-fection, compares the difference between bacteriophage and antibiotics therapy and also discusses the existing problems and the future development of this technique.

Abstract:Recently, many bacterial genome and transcriptome studies have been performed based on the next-generation sequencing technologies. Therefore, how to select the appropriate research strategies is becoming increasingly important. In this paper, we discussed the research strategies of bacterial genome and transcriptome based on the next-generation sequencing technologies, and stated the opportunities and challenges in these fields briefly. We reviewed the conventional methods and procedures and presented the existing problems briefly for bacterial genome and transcriptome studies. The research strategies of bacterial genome and transcriptome provide a relatively complete pipeline for the majority of bacteria. Moreover, it will promote the research of other fields, such as the course of life, biological evolution, basal metabolism, disease and drugs.

Abstract:Based on accumulated experiences in teaching practices of microbiology, constructing students’ atypical ideation and creative abilities in the teaching course is important to improve their innovative consciousness and ability. The author indicated two practical methods of eliminating thinking set and cultivat-ing reverse thinking.

Abstract:The structure of bacteria was one of the most basic content in the teaching of pathogenic biology. The understanding of the structure of bacteria has become even more in-depth, with the development of scientific techniques and research methods. In this assay, we brought some different points on it for discussion.

Abstract:The spirit of Blended learning was implemented in the cause of medical microbiology and parasitology teaching. In view of the students from different educational systems and medical specialties, different educational models such as the problem based learning (PBL), the case based learning (CBL) have been organically combined, and the promising approaches have been established to further conform the educational resources and to promote the experiment teaching reform for enhancing the teaching effect.

Abstract:This article explores the strategy which makes students play the main role in teaching and teachers play an encouraging role by interactive teaching method in bilingual teaching of microbiology. Chinese textbooks and original English textbooks have been chosen carefully in order to “be helpful in achieving personnel training goal” and ensure cultivation quality; English has been used flexibly ac-cording to the student conditions in the bilingual teaching based on the available bilingual teaching re-sources; classroom vitality has been promoted by combining microbiology theory and practice, English lectures and debates, etc; the evaluation mode has been reformed reasonably and so on to enhance the bilingual microbiology education results.

Abstract:The stroma of Ophiocordyceps sinensis showed a morphological diversity in major occurring areas of Ophiocordyceps sinensis in Gansu Province, a few samples have 2?4 stromata per endosclerotium or form dichotomous stroma. The morpha of developping stroma of Ophiocordyceps sinensis was systematically researched by transplanting culture. The ascospores germination of O. sinensis and the morpha of Hirsutella sinensis were observed. The results show that the fetility part of stroma obviously produces the alternation of contraction and expansion during the stage of ascospore ejection, and the culture of Hirsutella sinensis has two kinds of different color conidia, colorless or near black ones.