Abstract:[Objective] To determine the function of ribosome in fission yeast, while ribosomal protein L21 expression were disrupted. [Methods] We deleted rpl21-1 or rpl21-2 in the genome of fission yeast, by exchanging homologous regions. Determination of the ribosome synthesis and observation of the physiological properties were performed in rpl21-1Δ cells and rpl21-2Δ cells cultured in YEPD medium. [Results] Total expressed RPL21 in the rpl21-1Δ cells and rpl21-2Δ cells, including RPL21-1 and RPL21-2, was reduced by 66.5% and 58.7%, with the synthetic ribosome relevant reduced 62.8% and 50.4%, compared with wild type cells. In YEPD medium, both of the rpl21-1Δ cells and rpl21-2Δ cells were flocculated. This flocculation was suppressed by heterogeneous expression of RPL21-1 in the rpl21-1Δ strain or RPL21-2 in the rpl21-2Δ strain. [Conclusion] We suggest that it may be a common feature that reduction of ribosome level could trigger flocculation by disruption of any ribosomal protein expression in fission yeast.

Abstract:[Objective] To isolate and enumerate marine Bdellovibrio-and-like organisms (BALOs) by seawater (Sw) and polypeptone 20 (Pp20) double-layer agar media, and to reveal the diversity of cultivable marine BALOs in shrimp hatchery system. [Methods] We first compared the effects of the two media on enumeration of marine BALOs strains NA7 and NF1, as well as of BALOs in larval rearing water of Litopenaeus vannamei, then evaluated the diversities of BALOs isolated through prey range testing and 16S rRNA gene sequence analysis. [Results] Strains NA7 and NF1 both exhibited significantly higher (P<0.05) plaque numbers on Sw medium than on Pp20 medium if more prey bacteria were present. A total of 21 and 22 strains of BALOs were isolated from the same larviculture water by Sw and Pp20 media, respectively. According to prey range testing, 15 lytic patterns were differentiated from 43 isolates, of which 12 and 8 patterns corresponding to Sw and Pp20 were identified respectively. The 16S rRNA gene sequence analysis shows that all the BALOs isolates were affiliated to Bacteriovorax strains. Based on 97% sequence similarity, they could be divided into 6 phylogenetic clusters, and Sw and Pp20 media respectively recovered 6 and 4 clusters. [Conclusion] Medium Sw exhibited superior to medium Pp20 either for isolation and enumeration of marine BALOs or for diversity detection of their populations. The cultivable BALOs recovered from larviculture system of L. vannamei presented relatively high diversity. They all belong to the genus Bacteriovorax and are dominated by the clusters XIII, X and a potentially new cluster.

Abstract:[Objective] The diversity of culturable bacteria in saline alkali soil of Bishkek region in Kyrgyzstan was detected by Physiological test and phylogenetic analysis. [Methods] Using the screening media (R2A, TSB, 1/4 x NA and Gause No. 1 medium) containing 5% NaCl, salt resistant strains were screened. Based on morphological characteristics involving gram staining, salt resistance, growth temperature, pH tolerance and enzyme production performance, we researched the taxonomic identity and genetic variability of strains isolated by ARDRA classification map. [Results] One hundred and twenty salt-tolerant strains were isolated from Bishkek saline soil samples. Restriction enzyme Hae III was applied in ARDRA and 19 operational taxonomic units (OTUs) were assigned on the basis of the ARDRA patterns. Each OTU was randomly chosen for 16S rRNA gene sequencing. The phylogenetic analysis on the basis of 16S rRNA gene homology showed that all isolates affiliated to 17 genera, belonged to Firmicutes, Proteobacteria and Actinobacteria. Two of the isolates showed less affilation with known taxon (<97% sequence similarity) and may represent novel taxa. [Conclusion] The results suggest that the salt-tolerant bacteria are abundant, and some unknown taxa maybe exist in Bishkek region.

Abstract:[Objective] The shortage of phosphorus in the soil is one of the causes for declining of Pinus massoniana stands. One fungal strain Penicillium pinophilum JP-NJ4 which had strong capability to soluble phosphate was isolated from Pi. massoniana rhizosphere early. The research studied on inorganic phosphorus and organophosphorus-solubilizing capability of the strain. [Methods] Phosphate-solubilizing efficiencies on different phosphorus compounds, secretion of organic acids and enzymes of P. pinophilum JP-NJ4 were measured. Then phosphate-solubilizing characteristics of JP-NJ4 were analyzed. [Results] Four insoluble inorganic phosphates were used as a sole phosphorus resource for P. pinophilum JP-NJ4. The results showed that the strain JP-NJ4 had the highest phosphate-solubilizing capability for Ca3(PO4)2. The capacity to solubilize four inorganic phosphates was Ca3(PO4)2>AlPO4>CaHPO4·2H2O>FePO4·4H2O. It revealed that P. pinophilum JP-NJ4 mainly secreted gluconic acid, oxalic acid and malonic acid. The results of determining the activity of phytase and phosphatase showed that the phosphatase activity of the strain is higher. The strain JP-NJ4 also had certain phytase activity. The strain had a promising biodegradation function and its degradation rate of glyphosate reached 49.6%. [Conclusion] It showed that different chemical bonds had different effects on phosphate-solubilizing capability of the strain JP-NJ4. Phosphate-solubilizing capability and pH of fermentation broth was negatively correlated. Gluconic acid and oxalic acid had predominance in solubilizing Ca3(PO4)2 and AlPO4. The tested strain JP-NJ4 had an excellent phosphate-solubilizing function and great application potential on forestry biological fertilizer.

Abstract:[Objective] Sulfate reducing bacteria (SRB) anaerobic activated sludge was used in the process of flue gas desulfurization. This study aimed on the exploring optimal conditions for SRB to carry out sulfate bio-reduction, and analyze the impacts of heavy metal ions on sulfate bio-reduction. [Methods] The SRB anaerobic activated sludge obtained from an anaerobic sludge pool was domesticated under high sulfate concentration. The restrictive factors suppressing sulfate bio-reduction ability of SRB anaerobic sludge was investigated during the flue gas desulfurization. [Results] The domesticated SRB anaerobic activated sludge had a strong ability of sulfate reduction in a optimal culture condition (pH 6.5 and 32 °C). The function of sulfate reduction was obviously enhanced with additional Fe2+. In the sulfate reduction process, the optimum value of ThCOD/SO42? and ThCOD (theoretical chemical oxygen demand) were found of 3.00 and 3.33, respectively, and the sulfate reduction rate reached 72.15%. The activity of SRB was suppressed by 300 mg/L sulfide in the system of sulfate reduction. The heavy metal ions, Ni2+ and Pb2+, showed strong inhibition on SRB sulfate reduction ability at the level of 1.0 mg/L and 2.0 mg/L, respectively, meanwhile, Cu2+ inhibition at rather higher concentration (8.0 mg/L). [Conclusion] After domestication, the SRB anaerobic activated sludge shows a strong sulfate reducing function under optimal conditions, and it would be of great industrial potential for flue gas bio-desulfurization. In addition, the heavy metal ions which have negative impacts must be removed to ensure the efficient sulfate bio-reduction.

Abstract:[Objective] It was studied that the effects of MIG1 gene and glucose on cell morphology of Saccharomycopsis fibuligera and the mechanism exploration. [Methods] S. fibuligera was cultured in YPD mediums with different concentrations of glucose and MIG1 gene knockout strain was in YPD medium. We studied the relationship between intracellular glucanase and chitinase activities and cell wall glucan and chitin contents and cell morphological changes. [Results] When the concentration of glucose in the media was lower, the mycelium of S. fibuligera decreased, single-cell yeast increased, glucanase and chitinase activities increased, and then glucan and chitin contents in cell walls reduced. The concentration of glucose had no significant effect on MIG1 gene knockout strain: glucanase and chitinase activities of MIG1 gene knockout strain were remained at a high level, glucan and chitin contents in cell walls was also lower, and most of cells existed as the form of single-cell yeast. [Conclusion] MIG1 gene and glucose by multicopy inhibitor of glucose regulated glucanase and chitinase activities which affected glucan and chitin contents in cell walls, so that the cell morphology of S. fibuligera changed.

Abstract:[Objective] To provide the basis for its treatment, the effect of ultra-micro powder Dendrobium officinale on the molecular diversity of intestinal Lactobacillus in mice with spleen-deficiency constipation was studied. [Methods] The mice with spleen-deficiency constipation in treatment groups were respectively given the traditional decoction of Dendrobium officinale and 50% dose of ultra-micro powder Dendrobium officinale. The metagenome DNA of intestinal microflora was extracted from intestinal contents. Then ARDRA analysis was made after PCR by specific primer of Lactobacillus. [Results] The results showed that OTUs, Shannon index and Brillouin index in the normal group, the traditional decoction group and the 50% dose of ultra-micro powder group were the same, and all were larger than which in the model group. Compared with Lactobacillus community structure in normal group, the similarity coefficient was 0.333 3 in the 50% dose of ultra-micro powder group, 0.181 8 in the model group, 0.166 7 in the traditional decoction group. The cluster analysis and principal components analysis suggested that molecular diversity of intestinal Lactobacillus in mice changed by the effect of spleen-deficiency constipation model, and the two kinds of decoction of Dendrobium officinale regulated it in different ways. The Dendrobium officinale had obvious effect on the molecular diversity of intestinal Lactobacillus in mice with spleen-deficiency constipation. [Conclusion] The efficacy of 50% dose of ultra-micro powder Dendrobium officinale was the best in all treatment groups, and the molecular diversity of intestinal Lactobacillus in 50% dose of ultra-micro powder Dendrobium officinale group was closer to the normal group.

Abstract:[Objective] mreB1-5, the cytoskeleton-related genes of Spiroplasma melliferum CH-1 were cloned and expressed in Escherichia coli. Then their proteins properties were predicted. Expression levels of these genes in spiral and non-spiral shape of spiroplasma were determined. [Methods] Coding sequences of mreB1-5 were amplified from the genomic DNA of S. melliferum CH-1. Then recombination plasmids pETmreB1-5 were expressed in E. coli BL21 respectively after IPTG induction. Ni-NTA was used to purify the recombinant proteins. The properties of MreB proteins were predicted by online tools. Real-Time quantitative PCR method was applied to compare the expression levels of mreB1-5 genes between two obvious different shapes of S. melliferum CH-1. [Results] Five mreB genes from S. melliferum were cloned. The molecular weight of five MreB proteins were 36, 23, 23, 37, 25 kD, respectively. They were possibly hydrophobic proteins with no signal peptide and were identified as part of MreB/Mbl protein family. The results exhibited that the expression levels of genes mreB1-5 in non-spiral shape of spiroplasma were relatively lower than that in spiral shape. [Conclusion] This is the first report of clone and expression of spiroplasma cytoskeleton-related genes mreB1-5 which encode actin-like protein MreB. It could be inferred that these genes are closely related with spiroplasma morphology. All results contribute to further investigate the function of actin-like protein MreB in spiral shape and movement of spiroplasma.

Abstract:[Objective] hspB, the gene of the key monooxygenase in nicotine degradation from Pseudomonas putida S16, was cloned and expressed in Escherichia coli; protein HspB was purified, and the crystal condition of HspB was studied. [Methods] The gene hspB was amplified from the genomic DNA of Pseudomonas putida S16. Then recombination plasmid pET28a-hspB was expressed in E. coli BL21. Ni2+-NTA His·Bind and gel filtration were used to purify HspB. The preliminary crystal of HspB was screened and optimized by using hanging drop diffusion method. [Results] pET28a-hspB plasmid was successfully constructed and the protein HspB was purified to crystalline purity. Crystal condition of HspB was obtained and the culture condition is 0.2 mol/L NaCl, 0.1 mol/L HEPES pH 7.5, 1.1 mol/L (NH4)2SO4, 4 °C, Seeding. [Conclusion] The construction of the HspB purification system and the study of preliminary crystal of HspB lay a foundation for the research of structure-function relationship and improvement of HspB catalytic efficiency by directed evolution of gene manipulation.

Abstract:[Objective] The gene encoding estA in a strain of Acinetobacter sp. screened from abalone visceral was cloned and expressed in Pichia pastoris. [Methods] The estA gene was amplified and integrated into the genome of P. pastoris X33 via the pPICZα-C vector. The recombinant estA was expressed into the culture medium, and the recombinant protein were purified and characterized. [Results] The estA gene of 912 bp was cloned. After induced with methanol, recombinant esterase reached 1 200 U/L with weight of 33.7 kD. The optimum pH and temperature of recombinant esterase were 8.0 and 40 °C, respectively. Furthermore, this esterase exhibited remarkable stability at pH between 8.0?10.0 and under 60 °C. [Conclusion] The gene of estA from Acinetobacter sp. was successfully cloned and expressed in P. pastoris.

Abstract:[Objective] Using Agrobacterium-mediated transformation as a tool, we built a stable genetic transformation of Hypsizygus marmoreus. [Methods] After binary expression vector pYN6982 was transformed into Agrobacterium tumefaciens LBA4404, we transformed H. marmoreus SIEF3133 blended vegetative dikaryotic mycelia via Agrobacterium-mediated transformation. [Results] Dozens of transgenic strains of H. marmoreus with genetic stability were obtained after hygromycin resistance selection, PCR identification and mitotic stability test. By fluorescence microscopy analysis of randomly selected transformants, green fluorescence can be observed. This enhanced green fluorescent protein gene (egfp) has expressed in transgenic H. marmoreus. Moreover, two of eight randomly selected H. marmoreus transformants contain kanamycin gene (kan) sequences from outside the transferred DNA (T-DNA) border repeats using PCR analysis. [Conclusion] Transgenic strains of H. marmoreus with genetic stability and egfp expression were obtained. Also, DNA sequences from beyond the classically defined T-DNA border direct repeats can be transferred into the H. marmoreus mycelia. This phenomenon requires attention in H. marmoreus functional gene study.

Abstract:[Objective] In order to isolate Ralstonia solanacearum from Guangdong, Fujian, Guizhou tobacco, determine its virulence and to explore ways to determine virulence. [Methods] Triphenyltetrazolium chloride culture medium and protein electrophoresis were used to distinguish the virulence of the bacteria. [Results] Fifty-nine R. solanacearum were isolated from bacterial wilt tobacco samples. We used SDS-PAGE to identify bacterial wilt virulence. The specific band in the SDS-PAGE was considered to be a certification for the virulence of R. solanacearum. The 59 strains were divided into 2 types according to their virulence. Five strains were non-virulent whereas 54 were virulent. All virulent strains were dominators in Guangdong, Fujian and Guizhou province. Among these regions, Guangdong has a slightly large proportion of virulence strains, followed by Fujian and Guizhou. Among of these strains, one strain belongs to type Ⅳ bacterial wilt, the other 58 belong to biotype Ⅲ or subtype biochemical Ⅲ-1. [Conclusion] Virulence of R. solanacearum has differentiated, and specific protein band in SDS-PAGE can be used as an evidence to judge whether the bacteria has virulence or not.

Abstract:[Objective] To examine the effects of metal ions and protectants on activity of myrosinase and explore purification method of myrosinase produced by Trichederma atroviride T155. [Methods] By concentration of metal ions and protectants to study of the myrosinase activity was measured by adding different ions with different concentration and three protectants, respectively. The pure myrosinase was obtained by cell disruption, ammonium sulfate precipitation, dialysis, Sephadex G-100 chromatography, DEAE-52 chromatography and Sephadex G-200 chromatography in order. [Results] The results showed that Ag+, Zn2+, Pb2+, Mg2+, Hg2+, Fe3+ promoted enzyme activity of myrosinase at low concentration and inhibited enzyme activity at high concentration, Ca2+ promoted enzyme activity at the concentration of 0.069-17.000 g/L. 1 mmol/L EDTA associated with 3 mmol/L DTT was the best treatment for keeping myrosinase activity, and 85% enzyme activity was retained after 27 days of preservation at 4 °C. Molecular weight of the myrosinase produced by T155 was about 150 kD by SDS-PAGE, and this myrosinase was a dimer. [Conclusion] The tested metal ions inhibited myrosinase activity except for Ca2+, EDTA or associated with DTT showed preferable effect on maintaining myrosinase activity. A dimer myrosinase was obtained by separation and purification technology. This study intended to provide a new way and idea for mining myrosinase producing microorganism.

Abstract:[Objective] To obtain anti-Listeria monocytogenes specific single-domain heavy chain antibody by subtractive panning, and to analyse the enrichment rules of specific phage clones in biopanning against composition diversity and complex antigens. [Methods] The whole cell of heat inactivated Listeria monocytogenes was used as antigen to screen specific single-domain heavy chain antibodies from an alpaca non-immune phage displayed library by solid panning technique. After 4 rounds of conventional panning and 1 round of subtractive panning, a total number of 384 phage clones randomly picked from each round were characterized by Phage-ELISA, the positive clones were sequenced and the binding specificity was analyzed by Phage-ELISA. [Results] Two anti-Listeria monocytogenes specific single-domain heavy chain antibodies were obtained. [Conclusion] Whole cell-based panning strategy was feasible for isolation anti-Listeria monocytogenes specific phage display antibodies under the optimized conditions in this study. Subtractive panning was efficient and necessary to eliminate non-specific clones.

Abstract:[Objective] This study was to isolate, identify and characterize pathogenic bacteria from Erysipelothrix rhusiopathiae suspected cases or dead pigs from 8 different areas in Anhui Province. [Methods] The morphological, culture characteristics, biochemical test, PCR were applied to determine them, and then the drug-sensitivity test and protective immunity test were done. [Results] Twenty-nine E. rhusiopathiae strains were isolated; they were the same in morphological and biochemical properties. They were highly sensitive to Ampicillin and Cefatriaxone with 100% inhibitory among 18 antibiotics by drug-sensitivity test. The inhibition of Penicillin, Erythomycin and Cefotaxime was 93%, 89.7%, 75.9% respectively, though resistance to the other 13 antibiotics developed at different degree. The 8 isolates from different areas were highly lethal to mice, with LD50 between 14.30×102 and 2.36×102 CFU/mL. After immunized with commercial attenuated vaccine E. rhusiopathiae G4T10 strain through neck hypodermic injection, and challenged with 100 LD50 by lumbar injection, mice were 100% protected. [Conclusion] Isolated strains from different areas have the same biological characters, they were sensitive to beta lactam antibiotics. Commercial attenuated vaccine of G4T10 strain of E. rhusiopathiae can induce immune response to resist it.

Abstract:[Objective] Biofilm of Saprolegnia was developed in vitro and the effects of the environmental factors were studied. [Methods] The characteristics of biofilm formation of Saprolegnia parasitica ATCC200013 were investigated by modified microtiter-plate test, and the viability of Saprolegnia in the biofilms was detected by CCK-8. [Results] The OD450 value of Saprolegnia biofilm reached the peak after 24 h and stabilized after 48 h. OD450 value of biofilm significantly elevated with densities of initial Saprolegnia spores (P<0.05). The largest biofilm quantity was at 20 °C and 25 °C, which were significantly higher than the others (P<0.05). Saprolegnia can develop biofilm at initial pH between 4 and 11. When more than 0.12 mmol/L CaCl2 was added, biofilm formation of Saprolegnia was promoted. However, it played no significant role when 0.03 to 2.00 mmol/L MgCl2 was added. Cu2+ significantly affected the biofilm formation, while no evident biofilm was found when more than 0.5 mmol/L was added. Additionally, the biofilm formation was significantly inhibited by NaCl, but it played no significant role when less than 0.12% was added (P>0.05). Compared with the control group, the biofilms developed on the surface of the microtiter plate coated by the extract of skin or muscle showed no remarkable difference, while the biofilms on the microtiter plate coated by skin or gill mucus decreased. [Conclusion] A new method to form and measure Saprolegnia biofilm is successfully established. It describes for the first time that Saprolegnia biofilm formation can be affected by different environmental factors, which is beneficial to understand the growth of Saprolegnia biofilm and study further.

Abstract:[Objective] The high gibberellins-producing strains were screened and identified. Meanwhile, studies on characterization of genetic stability and fermentation in the bioreactor were also carried out. [Methods] Used the NTG, 60Co-γ rays and composite mutagenesis methods, high-yield mutant strains were isolated directionally in the medium including the antifungal agents-terbinafine. The genetic stability of mutant strain was determined by the several generations on the agar slants. The part of its fermentation characteristics were studied in the fermentation tank. [Results] The strains suspension was treated with the mutagens including a final NTG concentration 200 mg/L for 30 min, followed by 60Co gamma ray (300 Gy). The mutant strains were isolated on the PDA plate containing 120 μg/L terbinafine. After further shaking flask experiments, potentials of the mutant strains were determined. The fermentation titer of strain ZNL13-3 was 2 245±35 mg/L, increased 11.87% compared with the primary strains. The ZNL13-3 has a good genetic stability and value of application. Fermentation performance of ZNL13-3 is better than the primary strains, compared with the time trends of mycelia concentration and gibberellin acid concentration in the 5 L bioreactor. [Conclusion] The high-yield strains of gibberellin acid could be found and its ability to produce gibberellin acid could be affected by the terbinafine resistance.

Abstract:[Objective] To isolate and identify a fibrinolytic enzyme producing bacterium, and to analyze the component and characteristic of fibrinolytic enzyme. [Methods] Plasmin-producing bacterium was isolated by casein medium and AGAR-fibrin double-layer tablets from sea mud, soil, etc. Then its enzyme activity was measured by urokinase standard curve. The morphological, biochemical and physiological characteristics and 16S rDNA gene were analyzed to identify the taxonomic position of strain CNY16. The composition of the extracellular plasmin system was analyzed by SDS-PAGE and fiber protease zymogram. [Results] A strain named CNY16 with fibrinolytic activity was isolated and identified as Bacillus safensis. The results of SDS-PAGE and fiber protease zymogram showed that the extracellular fibrinolytic enzyme system contained at least two fibrinolytic enzymes with molecular masses of approximately 33 kD and 23 kD, respectively. The plasmin effectively dissolved fibrin clots, but did not hydrolyze blood cells. [Conclusion] CNY16 was a novel plasmin-producing bacterium, the fibrinolytic enzyme produced by strain CNY16 hold the valuable property in high activity and good stability. The strain might provide a new source for novel fibrinolytic enzymes.

Abstract:[Objective] Soybean peroxidase (SBP) will be widely used in immunoassay, and wastewater treatment and so on, due to its wide substrates, high specific activity, and good thermal stability. Nowadays, it was obtained mainly by extracted from soybean hull. However, it cannot meet the requirements of industrial applications for its low yield, high cost. In this study, SBP will be expressed in Pichia pastoris. [Methods] Both the genes of SBP and truncated C-terminal 20 amino acid SBP were cloned into pPIC-9K. These constructed expression vectors were transformed into Pichia pastoris X-33, and then be used to express SBP. Furthermore, the effects of asparagine glycosylation on SBP expression were also investigated by mutating asparagine into glutamine. [Results] Full length of SBP is inactive in Pichia pastoris. But the truncated C-terminal 20 amino acid SBP showed 23.5 U/mL. Our results indicated that glycosylation site of 144, 185, 197 have a great effect on the enzyme activity. These mutants were almost inactive; Whereas 211 and 216 deglycosylation sites had little effect on activity of SBP, can not be deglycosylation. [Conclusion] The highest activity of SBP was 510 U/mL in fermentation, which is the highest level of the reported.

Abstract:Peptides are transported into cells by peptide transporters, which are grouped into three types of oligopeptide transporters (Opp), dipeptide transporters (Dpp) and di- and tripeptide transporters (Dtp) in bacteria. Opp and Dpp belong to ABC-type superfamily and utilize the energy from ATP hydrolysis to promote peptide translocation. The most well-studied peptide binding subunits in Opp and Dpp are extracellular peptide-binding proteins OppA and DppA respectively, which recognize and bind substrates. Dtp are proton-driven symporters, belonging to major facilitator superfamily (MFS) superfamily. The elucidation of crystal structures combined with biochemical investigations of bacterial peptide transporters offers us a better understanding of their transport mechanism. This review summarizes the advances in the three types of bacterial peptide transporters.

Abstract:Solvent toxicity to producing microorganisms is one of the key stress elements during ethanol and butanol production by microbial fermentation. Furthermore, ethanol and butanol inhibit microbial growth and even cause cell death when the concentration reaches a certain value. Improvement of solvent tolerance of these microorganisms is important for industrial applications. Research on the ethanol and butanol tolerance mechanisms of microorganisms can provide basis for breeding of producing strains with improved solvent tolerance. In this paper, we reviewed ethanol and butanol tolerance mechanisms of microorganisms. The opportunities and challenges in the applications for biofuel and biotransformation are also discussed.

Abstract:The study on metabolism and biotransformation of natural products by human intestinal bacteria is receiving more and more attention. To gain insight and to trigger additional research in this field, we provide in this an overview of selected natural products bio-transformed or metabolized by human intestinal bacteria through the reported literatures in recent 20 years. The mechanism as well as pathway of metabolism or bio-transformation by human intestinal bacteria was discussed, according to the categories of natural products such as flavonoids, terpenoids, phenylpropanoids, alkaloids, steroids and the others. We also address the needs in further studies on metabolism and conversion action of natural products by human intestinal bacteria.

Abstract:Halophilic actonibacteria are a group of important extremophiles and have been attracting more and more research interests because of their unique habitats and physiological mechanisms. The conception of halophilic actinobacteria, biodiversity, and their secondary metabolites were reviewed in this paper. Furthermore, the existing questions and development prospects were analyzed based on the current status of halophilic actinobacteria in China.

Abstract:Planctomycetes, an independent bacterial phylum, is a cluster of important environmental microorganisms since occupying unique cell structure and genomic composition. Interestingly, Planctomycetes has a variety of ecological functions in the marine environments, such as participations in the ocean carbon cycle, anammox process, mineral encrustation, and algal bloom, and has become a hotspot of international research of marine microorganisms. However, there is no domestic comprehensive report on such field. Here we reviewed the current status of diversity and ecological function studies on marine Planctomycetes based on recent and important literatures. Finally, we also proposed some future focuses of such field combined with our own work.

Abstract:This paper focuses on the teaching reform of design and development of the Microbiology Tutor System by the Microbiology course group of Zhejiang University of Technology. The Microbiology Tutor System has more than 3 800 questions, abundant kinds of questions and functions of online practice and exams. Meanwhile, the system emphasizes function of tutor help, gives targeted assistance to students during the network learning, integrates functions of assignments on network and online submit, which can reflect students learning and teachers teaching in many ways, multi-level, and acquires preferably effect of the network-assisted teaching in the microbiology course. Finally, some problems in network assistant teaching and how to solve these problems have been discussed.

Abstract:[Objective] The objective of this paper was to provide an accurate and rapid determination method for the biomass of Monascus purpureus in solid-state fermentation (SSF). [Methods] The biomass and glucosamine content was measured by physical and chemical methods, then the relation between biomass and glucosamine content under different cultivation time, media and culture methods was investigated and the conversion relation of biomass and glucosamine content was built. Moreover, the PLS model for the relation between near infrared spectra and measured glucosamine content of medium was built. [Results] The rapid method for estimating biomass in SSF was built by measuring glucosamine content with NIR. The root mean square error of cross-validation of calibration set (RMSECV), the prediction correlation coefficient (Rp) and root mean square error of prediction set (RMSEP) of the best model were 0.648 5, 0.993 4 and 0.217 3, respectively. Besides, the accuracy of biomass calculation was enhanced by the conversion correlation. [Conclusion] On the base of the conversion relation of biomass and glucosamine content, the biomass of Monascus purpureus in SSF could be determined more accurately and rapidly by use of NIR method.

Abstract:[Objective] Understanding the genome size of Rhizoctonia cerealis is the basis for the genome sequencing and assembly. In this study, we estimated the genome size of R. cerealis via the quantitative real-time PCR method. [Methods] The partial translation elongation factor A gene (tef A) of R. cerealis strain R0301 was cloned and sequenced. Southern blot analysis indicated tef A was a single copy in the genome. Finally, we used the quantitative real-time PCR method to calculate the genome size of R. cerealis strain R0301 with the sequenced R. solani AG1-IA strain GD118 as the control. [Results] The quantitative real-time PCR method could accurately determine the genome size of R. solani and the genome size of R. cerealis R0301 was between 32.2-36.6 Mb. [Conclusion] Quantitative real-time PCR was a fast, highly accurate and reliable method for the genome size estimation of Rhizoctonia.

Abstract:dcm甲基化，链霉菌

Abstract:[Objective] In Escherichia coli, cytosine DNA methylation occurring at the inner cytosine in the sequence 5′CCWGG3′, is catalyzed by the DNA cytosine methyltransferase (Dcm) protein. Although dcm modification has been studied for nearly 37 years, the biological role for this gene is still unclear. In this study, we focus on the function of dcm in Streptomyces lividans. [Methods] dcm gene was isolated from E. coli and introduced into S. lividans 1326; HPLC-MS, methylation sensitivity assay and Southern blot are used to study the expression of dcm in S. lividans. [Results] the colony of dcm-containing exoconjugant is much smaller than wild type, and the production of actinorhodin in either MS agar plate or R5 liquid media was enhanced by two folds. [Conclusion] Epigenetic modification of the gonome of S. lividans by Dcm can activate the actinordin biosynthesis, providing an alternative way for genomic mining of cryptic bioactive metabolites.

Abstract: