Abstract:

Abstract:A bacterial strain named as WH-1 that can degrade cellulose was isolated from the rumen of the Mongolia sheep. The isolate was identified as Butyrivibrio fibrisolvens based on phenotypic and morphologic properties, the G+C mol% content of DNA and the 16S rRNA gene sequence analyses. In addition, the phylogenetic analysis of the 16S rRNA sequence also indicated that the isolate grouped closely with other members of Butyrivibrio fibrisolvens. The primary factors affecting the degradative ratio of cellulose were examined. The highest degradative ratio of filter paper reached 16.81%±2.99% under the conditions of 37°C, pH 7.0, inoculum size being 25%, and the percentage of cellobiose in total carbon sources being 20% within 72 hours of fermentation.

Abstract:The kinetics of neomycin productions by batch fermentation with Streptomyces fradiae HTP6 were studied. The mathematical kinetic models describing the course of Streptomyces fradiae HTP6 fermentation were established. The maximal specific growth rate μm was 0.0866 h-1 in exponential phase. The maximal specific production rate qp could reach 1.1867×10-4 g/(mL·h) in antibiotic production phase. The calculated results of models were compared satisfactorily with experimental data, the average relative deviation was no more than 5%. This kinetic model had practically guiding producing neomycin in fermentation of Streptomyces fradiae.

Abstract:A stable and efficient L-Malic acid accumulation mutant strain Rhizopus oryzae ME-M15 was discovered occasionally in the mutation breading for fumaric acid producers. Rhizopus oryzae ME-M15 gave a L-Malic acid output of 16.3 g/L on average after fermentation for 96 hours, more than 3 times than that of the parent strain ME-F10. In addition, other metabolites such as ethanol and fumaric acid were remarkably decreased in accordance with the depressed activity of the cytosolic isoenzyme of fumarase and alcohol dehydrogenase in strain ME-M15, while the activity of the pyruvate carboxylase had no significant difference.

Abstract:A aerobic moderate halophilic phosphate-dissolving bacterium, named QW1011, was isolated from the plant rhizospheres grown on the wall of ancient brine well located in Zigong city, Sichuan Province, China. The results showed that its cell was line shaped (0.8 μm×30 μm~100 μm), gram positive. The strain required aerobic conditions for growth and grew well with an optimum concentration at 10% NaCl (W/V) at pH 7.0 and tolerated up to 15% NaCl. And it could also hydrolyze gelatin and starch but not casein. 16S rRNA analysis revealed that its sequence sharing 100% similarity to B. Megaterium ATCC 14581. However, compared with B. Megaterium ATCC 14581 and B. Megatherium var. phosphaticum DSM 3228, QW1011 exhibited several differences in the phenotypic, physiological characteristics and ISR. Based on the phenotypic distinctiveness, molecular and ISR genetic evidence, it was proposed that QW1011 can be classified as genus Bacillus. The strain showed high phosphate-dissolving ability for Ca3(PO4)2 with the capacity of 62.42 μg/mL~71.34 μg/mL in Ca3(PO4)2 liquid medium at 24°C~36°C, 5%~10% sodium (W/V) and pH 6.5~8.0 after incubation for 60 h. And its activity for Ca3(PO4)2 was higher than for lecithin.

Abstract:The endophytic microorganisms found widely in many kinds of plants mediate various effects to theirs hosts. In this study, seven different dominant endophytes (SDE01 to 07) isolated from a Hyperaccumulator-Solanum nigrum L. were resistant to Cd2+, and the strain SDE06 survived even in the medium containing 80 mg/L of Cd2+. Bacteria strain SDE06 was identified as Bacillus sp.. The removal of Cd2+ of SDE06 in different conditions were studied. Under the optimal conditions, the incubating time was 36 h, the solution pH 6.0, the temperature was 37°C and the Cd2+ concentration of medium was 20 mg/L, the highest removal rate was up to 80.2% at this condition.

Abstract:The aim of this study was to examine the difference and change of Bacillus mucilaginosus proteins on weathering of phosphorite in order to provide further understanding of the molecular biological mechanism in the bacterial weathering. The concrete methods are described as follows: mineral powder was put into liquid culture medium and B. mucilaginosus was incubated in the medium. The control had no mineral powder in the medium. The treatment and controls were cultured simultaneously under the same condition. In 10 days, after the supernatant was centrifuged. The precipitation was used to analyze the protein differences between the treatment and the controls by 2-dimenttional gel electrophoresis (2-DE). Software and comparison of the 2-DE pictures of bacterial proteins revealed (1134±98) visible protein spots in the treatment group, and (729±53) visible protein spots in the control group. The difference had significance of statistics (P<0.05). To compare the bacterial protein expression contents of the treatment group with those of the control group, there were 496 differential protein spots, including 214 protein spots which indicated that the protein contents increased, 75 protein spots were indicative of a decrease, and 207 proteins were newly synthesized. It is proposed that some protein expression was activated after the input of mineral powder. Newly synthesized proteins, the increase of expression contents and reduction of proteins may be connected with bacterial metabolic regulations, cell activation and signal transmission. The results revealed the impact of mineral to bacteria, and the molecular biological mechanism about the adjustability of environment change.

Abstract:Endophytic fungal communities in 30 trees of three kinds of arbores Cinnamomum longepaniculatum (Gamble) N. Chao, C. camphora (Linn.) Presl and Quercus fabri Hance grown in the same condition at a plantation in Yibin, Sichuan province were studied. The results indicated that: there was considerable diversity of endophytic fungi in the three kinds of arbores, and the compositions of endophytic fungi were different in different organs of the same arbor; Phacodium Pers. was the dominant endophytic fungus in all three kinds of plants; the compositions of endophytic fungi exhibited low similarities between different tissues and different kinds of arbores. The endophytic fungi in C. longepaniculatum (Gamble) N. Chao had higher similarity to that of C. camphora (Linn.) Presl than to that of Quercus fabri Hance, but there was not significant difference between them. These indicated the compositions of endophytic fungi were affected by gene-type of host plant and climate factors.

Abstract:Biofilm has great influence for bacteria to resist the harm from outer environment. Its forming and development are controlled by many different genes. In this research, an insertional mutagenesis library of a wide type Bacillus amyloliquefaciens NK10.BAhjaWT was built via mini-Tn10 transposon system to find out genes involved in biofilm formation. Four such genes have been screened, in which, citB, citG, gpsA are all related to the energy metabolism. The function of another gene of yvfB is unknown. In a word, mini-Tn10 transposon system was proved to be efficient and stable in Bacillus.

Abstract:To construct expressing vector carrying esat6 gene and express this protein in Streptococcus gordonii GP251. esat6 gene was amplified by PCR with specific primer from genome of Mycobacterium tuberculosis (MTB)H37Rv. Inserted esat6 into the pMD18-T vector by T/A clone to get recombinant vector pMD18-esat6. Then digested pMD18-esat6 with restriction enzyme, esat6 was cloned to vector PSMB104 and expressed in Streptococcus gordonii GP251. The expression of esat6 protein was detected by Tricine-SDS-PAGE and Western-blot, ELISA technique was also used to detect its secretory volume. Restriction endonuclease, PCR, Tric ine-SDS-PAGE and Western-blot confirmed that esat6 gene was cloned into expressing vector successfully, and a 10 kD protein secreted in Streptococcus gordonii GP251, this protein has a good immunogenicity. The expression vector of esat6 gene was constructed, and esat6 protein expressed in Streptococcus gordonii1 successfully, it will be benefit for future study.

Abstract:A cellulase high-yield strain was identified and named as Trichoderma longibrachiatum SSL by ITS sequence identification. The endoglucanase1 gene (eg1) encoding endo-l,4-β-D-glucanase I was amplified by RT-PCR method, which including 1386 bp and encoding 461 amino acid. Sequence analysis showed that: This gene has a more 90% homology with the T. longibrachiatum eg1 gene. The eg1 gene encoding the mature peptide was inserted into the Pichia pastoris expression vector pPIC9K, which resulted in construction of the recombinant expression plasmid, ppic9k-eg1. The ppic9k-eg1 was then introduced into the host Pichia pastoris GS115. After the induction of methanol, extracellular recombinant endoglucanase I from the supernatant of the recombinant Pichia pastoris strain reached 73 U/mL. A clear strengthening of the protein bands, whose molecular weight is about 58 kD, appeared in the SDS-PAGE.

Abstract:98 yeast strains were isolated from soil samples collected from 10 counties in the east part of Qinghai Province. These strains were identified mainly based on the 26S rDNA D1/D2 domain sequence analysis and morphological and physiological characterization. Diversity and distribution of the yeast species in the soil samples were analysed. Among them, 13 species belonging to 10 genera were recognized (two strains might represent two new species). The dominant species identified were Galactomyces geotrichum and Rhodotorula mucilaginosa.

Abstract:A strain of bacterium (CGMCC No. 1982) was isolated from a corn leaf spot infected by Bipolaris maydis. The strain exhibited extensive antagonistic effect on quite a number of plant pathogenic fungi such as Bipolaris maydis, Magnaporthe grisea, Fusarium graminearum and so on. The strain was identified as Bacillus subtillis based on the 16S rDNA sequence homology, and the physiological and biochemical characteristics and morphological observation. The antagonistic substances prepraed by adding 60% saturation of ammonium sulfate to cultivating medium of the strain exhibited higher antifungal activity. The physical and chemical character of the antagonists was tested using Bipolaris maydis as indicator. The results suggested that the antagonists were of thermal stability and acidic-basic stability. However, the antagonists were sensitive to protease and chloroform, partially sensitive to Ultraviolet. Therefore, the strain has a bright developmental prospect as a novel biocontrol bacterium.

Abstract:Both culture-dependent and culture-independent methods, denaturing gradient gel electrophoresis (DGGE) based on the sequence of 16S rRNA V3 region gene, were used to examine the total bacteria counts, bacterial diversity and community structure of different periods Brassica juncea saline water samples. The results showed that 7 genera of bacteria were identified from 19 isolated bacterial populations by the traditional isolation method, the dominant bacteria in intestine belonged to Acidobacterium. By 16S rRNA V3 region gene DGGE method, 11 distinct bands were obtained from 16S rDNA amplifications. The profile of DGGE fingerprints of different periods saline water revealed that the most dominant bacteria group was Leuconostoc in the process of the fermentation. This suggested that a combination of molecular and traditional culture methods can be used to analyze and monitor the diversity of the process of fermentation microflora effectively, and that will give us more information of microorganism diversity.

Abstract:Pure culture of Phlebopus portentosus was inoculated in the roots of coffee tree. The results indicated that the young fruit bodies would come out around the rhizomes of host tree after inoculation in 30 to 90 days, single or cluster, 3 to 4 days for mature, weight 20.0 g to 62.0 g. Brown rhizomorph and hyphae can be seen on the seedlings`rhizome, main root and side root while nothing is on the tip of the root.It was found that rhizomorph on the surface of roots would die after inoculation in 90 days in pot.

Abstract:Fat Particles Counting(FPC), Yeast Mud Dying by Sudan III(YMDSIII), Culture of Lacking Carbon(CLC) were compared and approached in the essay. The results show that YMDSIII is simple and direct, its results are better interrelated with oil-producing quantity of yeast. This method is a relatively ideal screening method on choosing oil-producing microorganisms. CLC is relatively accurate, but it is too tedious. By comparison, FPC is simple and convenient, but it is short of accuracy. When it is used, it must consider the size of fat particles. By screening, cellular oil content reached 54.25% (W/W).

Abstract:To investigate the bioactivity of Nocardia rubra Cell (NC), the mice were used to assay the toxicity, the effects on immune organs, phagocytes of peritoneal macrophage and the antitumor activity by perfusion of NC to the stomach of mice. Results indicated that NC could obviously stimulate in vitro the phagocytosis of peritoneal macrophage from mice, and remarkably inhibit the growth of S180 in mice, and its LD50 was more than 10 g/kg. In conclusion, NC had low toxicity, it could significantly enhance the organism immunologic function and had obvious antitumor effect and the anti-infection effect against a pathogenic microorganism.

Abstract:One marine actinomycete strain FIM02-523 was isolated from marine soil in the East China Sea in Fujian Province. The fermentation broth of strain FIM02-523 exhibited potent antitumor activities. Strain FIM02-523 grew well on most media tested, the colonies were orange to dark brown but lacked aerial hyphae, no diffusible pigments were observed. Phylogenetic, chemotaxonomic, morphological analyses, physiological and biochemical characteristics demonstrated that strain FIM02-523 belong to the genus Micromonospora, may be a strain of the type species Micromonospora chalcea.

Abstract:To improve and optimize marine antimicrobial peptide R-1 production by a newly isolated Brevibacillus laterosporus Lh-1, Plackett-Burman (PB) design and response surface methodology (RSM) using central composite design was adopted in culture conditions. MINITAB 15.0 was used for planning the experiments, data analysis, contour diagrams and response optimizations. In this study, PB design was undertaken to evaluate the effects of the fifteen factors. By the statistical regression analysis, the significant factors affecting the novel antimicrobial peptide R-1 in submerged fermentation by Br. laterosporus Lh-1 were determined as follows: glucose, peptone and CaCl2. Then a RSM was used to optimize the above critical internal factors, and the optical concentration of the variables were determined as: 15.72 g/L glucose, 6.01 g/L peptone and 3.29 g/L CaCl2. The content of R-1 was increased from 82.15 kU/mL to 116.27 kU/mL.

Abstract:Eighty-five endophytic fungal strains were isolated from the roots、stems and leaves of Polygala tenuifolia Willd, among which, fifty-two from natural plants and thirty-three from cultivated ones. Seventy-six strains were classified as twenty-three fungal genera. The inhibitory activity screening to fourteen microbe were conducted research. The results showed that some endophytic fungi had remarkble inhibitory activities to Bacillus subtilis, Shigella sonnei, Escherichia coli, Candida albicans, Fusarium kyrushuense and they were all belonged to Fusarium, Alternaria, Aphanocladium respectively. All of the endophytic fungi isolated from Polygala tenuifolia showed no inhibitory activities to Staphyloccocus aureus, Salmonellae enteritis, Bibrio parahemolyticus.

Abstract:Chlamydia pneumonia(Cpn) is thought to be one of the important pathogens which are associated with coronary heart disease. It can induce the activation of host signaling pathways to maintain the survival and metabolism of itself in the cell, and finally leads to disease. The ORFs of Cpn0148 encoding eukaryote-like serine/threonine protein kinase was amplified from Chlamydia pneumonia serovar AR39 genomic DNA. The amplified product was cloned in pGEX-6p and expressed in XL-1blue. DNA sequencing showed that the whole ORF is about 1860 bp, encoding a protein with 619 amino acid. The molecular weight of Cpn0148 is about 70 kD. Polyclonal antibody was obtained from immune BALB/c mice with the Cpn0148-GST fusion protein, and the expressing of Cpn0148 was detected on the bacteria organism by immunoflouresence. The finding of Cpn0148 protein is very helpful foundation for further study of the host-bacteria interaction.

Abstract:Based on Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI- TOF-MS) method for discrimination of pathogenic bacteria was developed. Established the standardization method for MALDI-TOF-MS analysis of bacteria and affecting elements of the analyzing result. The results obtained from twelve plants pathogenic bacteria of different genus, species and subspecies were analyzed by using MALDI-TOF showed that, MALDI-TOF-MS could be rapid and reliable identification of bacteria at the level of genus, species, and strains. Analytical process is simple, high sensitivity are advantages of this strategy.

Abstract:Cyclic diguanylate (c-di-GMP) is a bacterial second messenger of growing recognition involved in the regulation of a number of complex physiological processes. In combinations to the related progress of Xanthomonas oryzae pv. oryzae, the causing agent of bacterial blight of rice in our lab, this review describes (1) the biosynthesis and hydrolysis of c-di-GMP and several mechanisms of regulation of c-di-GMP metabolism, (2) the contribution of c-di-GMP to regulating virulence, motility and biofilm formation, processes that affect pathogenesis of many bacteria, and (3) ways in which c-di-GMP may mediate these regulatory effects.

Abstract:It is common in bacterial genomes of the integration of prophages. As an important participant of the vital movement of their hosts, prophages affect closely the biological properties of the hosts. Therefore, if we want to comprehend a bacterial genome fully, it is essential to recognize and understand accurately prophages in it. This article is a compendious review about the classification, distribution, identification, evolution of prophages and the interaction with their hosts.

Abstract:Papers on mycorrhizas were searched from SCI (Science Citation Index) database. In order to understand the research progress of mycorrhizas in China, the paper on mycorrhizas from 1989 to 2007 was analyzed with method of bibliometrics. Mycorrhizal researches showed an increasing tendency during 1989 to 2007, while the increase was obviously accelerated after 2000. Only 5.22% of the articles were published in journals with impact factor above 5, indicates that the academic levels of researches need being enhanced. Currently the research on mycorrhizas was mainly focused on Arbuscular mycorrhiza (AM), especially on effects of mycorrhizal fungi on plant physiology, effects of mycorrhizal fungi on resistance of host plants, Mycorrhizal diversity community and ecological distribution, and phytoremediation with Mycorrhizal plants. The future research should emphasize in phytoremediation with Mycorrhizal plants and identification of fungal species with molecular biological technology.

Abstract:Heredity and variations are most essential problems in biology. Estimating the mutation rates will be a great help for well understanding the difference among the different genes, different biological species, and under different growth environments. Bacteria are the best mode for estimating mutation rates due to their fast growth rates and their huge population sizes. Mutation rate (μ) is defined as the probability of mutation in each bacterial cell and each bacterial generation, usually expressed as Here, is the number of mutations, and is the number of generations. In some famous microbiology and genetics textbooks and monographs, ln2, as the synchrony coefficient for non-synchronous bacterial population, was introduced into the mutation rates calculation formulae, but in others not. So, how to calculate the mutation rates in non-synchronous bacterial population? Just introduce coefficient ln2 is enough? In this essay, by analyzing the mathematical characteristics of exponential growth in bacterial population, both synchronous and non-synchronous, the biological meaning of ln2 was been well expressed, i.e., It means, in non-synchronous population, the ratio of generation time (TG) to doubling time (TD) is ln2. However, in ideal synchronous population, the generation time (TG) is equal to the doubling time (TD). Because in non-synchronous population, the number of generations was usually estimated by the experimental data, these data had been already included the non-synchrony factor of the experimental population, it was no need to introduce ln2 as synchrony coefficient into mutation rates calculating formulae. If the number of generations was not estimated by experimental data, it was need to carefully calculate the value of generations based on the given data, rather than just introduced ln2 as synchrony coefficient into mutation rate calculating formulae.

Abstract:The traditional fermentation engineering experiment requires a reform on the experimental contents and teaching pattern. According to the production process of industrial enzymes, we set up a two-week comprehensive experiment. The students designed and prepared the experiment by themselves. Moreover, the pattern of self-management was used in the process and the experiment scores included the self-assessment and objective assessment. It was proved that the new teaching pattern increased the study interesting of students, inspired their initiative and trained their spirits of team cooperation. The teaching effect was improved markedly and good ideas are also put forward to solve the possible problem.