Abstract:

Abstract:[Objective] This study focuses on the influence of overexpression of TatAdCd translocases in Tat pathway on the secretion of LipA in Bacillus subtilis. [Methods] The promoter and mRNA leader region of the operon tatAD-CD were replaced by the tandem promoter and mRNA leader region of cdd gene and this modified gene was inserted into sacB gene. The expression level of the tatAD-CD operon was characterized by qRT-PCR. We transformed the plasmid pHP13L which can express lip gene of Bacillus subtilis excessively into the recombinant strain. The influence of overexpression of TatAdCd translocases on the secretion of LipA was assessed by SDS-PAGE and measuring the enzyme activity of the recombinant in fermentation broth. [Results] The modified tatAD-CD operon was expressed successfully. Compared with the control strain, the relative transcription level was improved by 185 times. The enzyme activity of recombinant in fermentation broth was increased by 40% due to overexpression of TatAdCd translocases. [Conclusion] The tandem promoter and mRNA leader region of the cdd gene can increase the expression level of the target gene effectively. LipA can be secreted to extracellular through Sec pathway and Tat pathway in Bacillus subtilis. The overexpression of tatAD-CD operon can promote the secretion of LipA.

Abstract:[Objective] We explored an appropriate resin to immobilize β-fructofuranosidase (β-FFase) to produce lactosucrose. [Methods] β-FFase was immobilized onto nine adsorption and ion-exchange resin, to select the best resin for immobilization. To improve immobilization efficiency, β-FFase was immobilized onto the resin modified by polyethylenimine (PEI). A series of immobilization conditions were optimized. The stability of the immobilized enzyme and lactosucrose synthesized by the immobilized enzyme were also explored. [Results] Ion-exchange resin D311 was excellent for β-FFase immobilization. Immobilization efficiency was improved apparently when D311 resin activated by PEI. The immobilized conditions were as follows: 2% PEI, 103 U/g resin, 25 °C, pH between 6.0 and 8.0, 8 h adsorption time. Under these conditions, the immobilized enzyme activity reached 57 U/g, and immobilized yield was 55.3%. Using the immobilized β-FFase to hydrolysis 1 mol/L sucrose, the immobilized enzyme can be used for 15 times with no apparently activity loss, and approximately 137 g/L lactosucrose was synthesized within 8 h. [Conclusion] β-FFase immobilized onto the resin modified by PEI showed a good operational stability and a high productivity of lactosucrose.

Abstract:[Objective] Gene arcA encoding arginine deiminase from Pseudomonas putida JUCT1 was integrated into the genome of Escherichia coli JM109(DE3) to enhance its organic solvent tolerance (OST). [Methods] Using genome of P. putida as template, we amplified arcA gene and expressed it in strain E. coli JM109(DE3). Subsequently, arcA gene was integrated into the genome of E. coli JM109(DE3) by red-mediated recombination to obtain a strain with an inheritable OST phenotype. [Results] When growing in 2.0% (V/V) cyclohexane, 0.1% (V/V) toluene, 4.0% (V/V) decalin and 0.1% (V/V) butanol, the OD660 values of recombinant E. coli JM109(DE3)/pET-20b(+)-arcA could reach about 0.8, 0.9, 1.8 and 1.3, respectively. [Conclusion] Our results demonstrate that microbial OST could be enhanced by the expression of arcA gene. Importantly, this work provides experimental data and molecular basis for constructing OST bacteria for industrial applications.

Abstract:[Objective] Two-stage thermophilic and mesophilic sludge anaerobic digestion process, which combines the processes of thermophilic digestion and mesophilic digestion, is a potentially important strategy for the development of sludge anaerobic digestion. Thus, it is necessary to investigate and compare the microbial community compositions in thermophilic and mesophilic anaerobic digestion systems. [Methods] Based on high-throughput sequencing and GeoChip techniques, we checked the 16S rRNA gene sequences of bacteria and archaea, ITS sequences of fungi and virus and virulence genes in anaerobic digestion systems, then compared the taxonomic and functional compositions between thermophilic and mesophilic microbial community. [Results] The taxonomic compositions of bacteria and archaea and the functional compositions of virus and virulence differed significantly between thermophilic and mesophilic anaerobic digestion systems, while the fungal taxonomic compositions were similar and the sequence reads number were relatively low. Methanogenus and unclassified bacteria and archaea were more abundant in mesophilic condition, while acid-producing and thermophilic microbes were more abundant in thermophilic condition. The relative abundance of genes associated with virus and virulence decreased after thermophilic digestion. In addition, microbial community compositions were significantly correlated with COD, TS and VS. [Conclusion] Microbial community compositions were significantly different between thermophilic and mesophilic anaerobic digestion, which explained functional distinction between the two ecosystems. The succession of microbial community was associated with influent parameters, revealing an important sensitivity.

Abstract:[Objective] Concerning the special biochemical characteristics of sulfur oxidizer, we optimized related restrictive factors during the process of oxidizing sulfide to elemental sulfur for improving productivity of the elemental sulfur. [Methods] A typical desulfurization strain Thermithiobacillus tepidarius JNU-2 (T. tepidarius JNU-2) was used for oxidizing sulfide into elemental sulfur. The culture trait and desulfurization performance was respectively studied with Na2S2O3 as the energy substrate. Then the process of oxidizing sulfide into elemental sulfur related restrictive factor was optimized via single factor experiments. [Results] With Na2S2O3 as the sole energy substrate, μmax of T. tepidarius JNU-2 was 0.207 h?1 and the final biomass was 4.0×106 cells/mL. Nearly 98% Na2S2O3 had been consumed at 24 h and elemental sulfur production reached the maximum value 0.8 g/L. Then elemental sulfur was gradually oxidized and eventually maintained at 0.2 g/L. The optimum conditions of major restrictive factors such as carbon and nitrogen source, MgSO4, FeSO4 and energy substrate was determined through the single factor experiments as follow. CO2, NH4Cl 0.5 g/L, MgSO4 0.5 g/L, FeSO4 0.1 g/L, Na2S2O3 15.0 g/L. After optimization, the maximum biomass reached 4.0×106 cells/mL during the process of oxidizing Na2S2O3 into elemental sulfur and its titer was increased to 1.14 g/L, which was improved by 42.5% compared to the previous non-optimized one. [Conclusion] The efficiency of elemental sulfur from oxidizing sulfide by chemoautotrophic T. tepidarius JNU-2 could be effectively improved via optimization of major restrictive factors.

Abstract:[Objective] The diversity of the glycosyl hydrolase family 10 (GH10) xylanase gene of fecal microorganism of Rhinopithecus bieti is studied. [Methods] Using the genomic DNA extracted from the feces of wild and half-wild R. bieti as template, we amplified xylanase gene fragments by degenerate primer of GH10 xylanase. Bacteria clone library is constructed and analyzed using pMD19-T vector. [Results] From fecal microbial clone library of wild and half-wild R. bieti 26 and 28 GH10 xylanase gene fragments are respectively acquired, whose identity with xylanase sequences in GenBank varies from 58%?95% to 63%?81%. Blast results shows that microbial composition of GH10 xylanase from two different environments is similar, including the Firmicutes, Bacteroidetes and uncultured bacteria. GH10 xylanase gene of fecal microbiome of wild R. bieti derives from Uncultured bacterium, Butyrivibrio, Bacteroides, Ruminococcus, Sphingobacterium, Chryseobacterium, Clostridium, Bacillus, while that of half-wild R. bieti only from Uncultured bacterium, Clostridium, Paludibacter, Sphingobacterium, Ruminococcus, Roseburia, Chryseobacterium. There is GH10 xylanase existing in both environments, including Ruminococcus, Clostridium, Chryseobacterium, Sphingobacterium. [Conclusion] There are abundant GH10 xylanase genes in fecal microorganism of wild and half-wild R. bieti and there is some difference in their microbial sources. This research enriches the diversity of GH10 xylanase in animal gastrointestinal tract as well as sets foundations for the exploitation of novel xylanase and the utilization of microbial resources in R. bieti’s gastrointestinal tract.

Abstract:[Objective] We studied secondary metabolites of endophytic Micromonospora sp. M66 of Tripterygium wilfordii Hook. f., a rare actinomycete, provide structurally diverse compounds for microbial drugs and pesticides development. [Methods] Combining thin-layer chromatography, silica gel column chromatography, gel chromatography and semi-preparative high-performance liquid chromatography, we purified the secondary metabolites from Micromonospora sp. M66. By using the spectroscopic techniques, we elucidated their chemical structures. [Results] Seven compounds were purified and their chemical structures were elucidated through spectroscopic analysis including mass spectroscopies and nuclear magnetic resonance (NMR) spectroscopies. These 7 compounds were a set of indole alkaloids derived from tryptophan or indole. Compound 2 was an important plant growth regulator. Compound 3 showed a notable growth inhibition of lymphocytic leukemia cell P388, Bacillus subtillis and Saccharomyces cerevisiae, whereas compound 6 exhibited a significant inhibiting activity against Staphylococcus aureus. [Conclusion] Compounds from the bacteria of the genus of Micromonospora produce indole alkaloid-like secondary metabolites by using indole or tryptophan as a starting material and have potential as new alkaloid-like drugs.

Abstract:[Objective] A new source of oil, produced by microorganism, was studied in the article. [Methods] Nine kinds of the main compositions were separated by twice slica column chromatography from the oil produced by Sporidiobolus pararoseus. The compositions were identified and quantized by thin layer chromatography, HPLC and HPLC-MS. [Results] The predominant fractions were squalene, β-carotene, γ-carotene, ergosterol esters, torulene, triglyceride, free fatty acids, ergosterol and torularhodin. The concentration of total ergosterol was about 3.2 g/kg in the Sporidiobolus pararoseus oil, and 16.7 % of the ergosterol exists in the form of ergosterol ester. The concentration of squalene in the oil was about 1.25 g/kg. The concentration of carotenoids in the oil was approximately 0.4 g/kg. Besides, the fatty acids compositions of ergosterol esters and triglyceride were also studied. There was about 73% oleic acid in the oil. [Conclusion] These results showed that S. pararoseus oil can be a good source of functional oil.

Abstract:[Objective] To express and purify the regulator protein Sigma K (σK) from Bacillus thuringiensis HD73 in Escherichia coli. [Methods] The ORF (open reading frame) of the sigK gene was amplified by PCR from Bt strain HD73, and then cloned into the vector pET21b to generate pETsigK. The pETsigK was transformed into BL21(DE3). The SDS-PAGE, nickel column affinity purification, Q-Sepharose fast flow column purification and electrophoretic mobility shift assay (EMSA) experiments were carried out to analyze the purity and binding activity of His-Sigma K with cry1Ac gene controlled by Sigma K in vitro. [Results] The 27 kD His-Sigma K was expressed. EMSA results showed that the His-Sigma K could bind to the promoter of cry1Ac gene, which is controlled by Sigma K. [Conclusion] The His-Sigma K protein was successfully expressed and purified. The purified His-Sigma K could bind to Sigma K-controlled promoter.

Abstract:[Objective] This study aimed to clone and characterize a CYP51 homologous gene in Penicillium italicum. [Methods] PCR and Genome walking strategies were used to obtain the gene sequence and its flanking region. Gene structure was analyzed by bioinformatic strategy: Gene transcriptional start site was predicted by NNPP software and TFSEARCH1.3 software was used to predict transcriptional factor binding sites. Homology modeling was performed using human CYP51 protein as the template through the online software SWISS-MODEL. [Results] A CYP51 homologous gene was successfully cloned from Penicillium italicum and named as PiCYP51B. A 3 496 bp sequence including 910 bp 5′ flanking sequence and 834 bp 3′ flanking sequence was obtained. The ORF of PiCYP51B is predicted to encode a protein of 525 amino acids. PiCYP51B contains three introns length 74, 51 and 52 bp, located between 247 bp and 320 bp, 519 bp and 569 bp, 1 635 bp and 1 686 bp respectively. The transcriptional start site is located 458 bp upstream of the initiation codon; the upstream regulatory region not only contain the core structure TATA box (located at 25 bp and 105 bp upstream of the initiation codon), but also contain several transcriptional factor binding sites such as Abd-B, ADR1, AP-4, GATA-1, CdxA, Clox and Oct-1. The proportion of purine is relatively high in the upstream regulatory region. From 387 bp upstream, there are four consecutive heat shot protein transcriptional factor binding sites (HSF); there are three consecutive CdxA transcriptional factor binding sites from 106 bp upstream. To further analysis the structure of PiCYP51B, homology modeling was performed using the online software SWISS-MODEL. [Conclusion] PiCYP51B, being the homologous gene of CYP51 may connect with the resistance to pesticides of P. italicum.

Abstract:[Objective] To produce Bacillus thuringiensis Bt519-1 as biocontrol agent with enhanced antifungal and insecticidal activity. [Methods] A recombinant plasmid, pDM, containing a constitutive high expression promoter and the chitinase gene chiMY from B. licheniformis, was constructed and transferred into strain Bt519-1 by electroporation. Zymogram analysis was used to test the constitutive expression of chitinase of strain Bt519(pDM). Inhibitory activity of the engineered strain was measured against 10 species of fungi that are plant pathogens. The most sensitive fungus was selected to test in pot culture experiments. Roots of Capsicum annuum seedlings were irrigated with various concentrations of the Bt crude enzymes, inoculated with the fungal sporangial suspension 12 h later. The plant disease index and control efficacy were determined 7 d after inoculation. [Results] SDS-PAGE and zymogram analysis confirmed that strain Bt519(pDM) expressed chitinase (68 kD). Inhibitory of Bt519(pDM) was effective for 5 of the 10 tested fungi of which Phytophthora capsici was most sensitive. Pot culture experiments demonstrated that the control efficacy of Bt519(pDM) against P. capsici was 73.2%. The half lethal concentration (LC50) of Bt519(pDM) against the moth Heliothis armigera was 121.26 mg/L. [Conclusion] Bt519(pDM) has potential as an antifungal and insecticide.

Abstract:[Objective] we test the influence of RND family efflux transporter, MFP subunit cusB gene, on the copper resistance for Acidovorax citrulli. [Methods] Transposon (Tn5) was inserted into the genome randomly screened to prepare mutant strains constructed by functional complementation biparents mating and discussed on the effect of RND family efflux transporter MFP subunit cusB gene on the copper resistance for A. citrulli on basis of the copper resistance for A. citrulli, extracellular cellulase and extracellular protease secreted extracellular polysaccharide production, biofilm formation, virulence and motility etc. [Results] The mutant ΔcusB can’t be grown when it contained the 1.25 mmol/L CuSO4 or 2.5 mmol/L flat on KMB. The structure of cusB extracellular polysaccharide secretion and biofilm formation A. citrulli can be different from wild-type due to the effect of the mutant gene. Whatever, the mutant gene can’t directly affect the extracellular cellulase enzymes, extracellular protease, pathogenicity and allergic reactions also be obtained in our investigation. [Conclusion] The biological characteristics of A. citrulli can be affected by cusB associated mutations. Meanwhile, cusB associated mutations affect the copper resistance for A. citrulli.

Abstract:[Objective] Identification the chemical structure of chitinase GcCHI1 that isolated and purified form Gliocladium catenulatum HL-1-1 strain, and tested the antifungal effects and revealed the antifungal mechanism on several kinds of plant pathogenic fungi. [Methods] Nano-ESI-MS/MS methods and Oxford cup method. [Results] Peptide mass fingerprint atlas of trypsin hydrolysis peptide, MS/MS atlas and 3 peptide amino acid sequences (<15 amino acids), called LYNSNDAIEAFISR, VIGYFTQWGIYGR and LNLGIGYYGR were received. After blasted in the Mascot database, GcCHI1 was found the highest homology similarity with chitinase A of Stenotrophomonas maltophilial strain 34S1. Another result about antifungal effects and antifungal mechanism found chitinase GcCHI1 inhibited hyphal elongation, spore germination and sclerotium germination of such strains as Rhizoctonia solani, Sclerotinia sclerotiorum, and Botrytis cinerea et al.. [Conclusion] This paper analyzed the chemical structure of chitinase GcCHI1. And revealed the antigungal mechanism of biocontrol fugus HL-1-1 for chitinase GcCHI1’s antifungal activities.

Abstract:[Objective] Antibacterial activities of fermentation culture and dominant functional microbes in the acetic acid fermentation of Zhenjiang aromatic vinegar were evaluated. [Methods] The agar diffusion method was utilized to test antibacterial activity of the different samples. Effects of heating, protease hydrolysis, dialysis on the antibacterial activity of fermentation broth of functional microbes were determined. [Results] The result showed that the growth of four indicator strains were significantly inhibited by water extraction of fermentation culture and culture supernatants of 4 functional microbes, including Acetobacter pasteurianus, A. pomorum, Lactobacillus helveticus and L. plantarum. The antibacterial substances were thermo-stable, sensitive to proteases and the molecular weight was identified to be lower than 8 kD. [Conclusion] Diverse kinds of components contribute to the antibacterial activities of fermentation culture and functional microbes.

Abstract:[Objective] The aim of the study was to determine the composition and diversity of microbial communities in the distal gut of mink (Mustela vison). [Methods] The composition and diversity of distal gut content bacteria were investigated by the high-throughput sequencing. [Results] A total of 146 287 filtered high-quality representing 17 phylum and 167 genus bacterial phylotypes (operational taxonomical units, OTUs) were identified in distal gut contents samples from 10 healthy mink. There are mainly Firmicutes (59.99%), Bacteroidetes (16.2%), Fusobacteria (11.5%), the Actinobacteria (5.9%) and Proteobacteria (5.3%), which has the largest number of Firmicutes. Clostridiales was the most diverse bacterial order in Firmicutes, but Streptococcus, with 50% of all OTUs, was the most diverse bacterial genus in Clostridiales. [Conclusion] The findings of this study will facilitate the next step in understanding the complex phylogenetic diversity of the microbial communities in the intestinal tract of mink.

Abstract:[Objective] To provide theoretical basis for using probiotics to prevent and treat the diarrhea weaning rabbit, the experiments were performed to explore the structural changes of cecum microflora in the diarrhea rex rabbit. [Methods] Total DNA were extracted from the cecum contents of 5 healthy and 5 diarrhea rex rabbits respectively. PCR-DGGE and Real-Time PCR were applied to analyze the differences of Cecum microflora between the healthy and diarrhea rex rabbits. [Results] Through the analysis we found that the richness, evenness and diversity index of PCR-DGGE profiles bands were not significant difference. But clustering analysis and Principal Component Analysis (PCA) could distinguish diarrhea group from healthy group. Real-Time PCR detection showed that in the diarrhea rabbit, despite the number of the population of normal intestinal flora including Prevotella, Clostridium clusterⅠ was not changed (P>0.05), the population of Streptococcus spp., Clostridium leptum group, Bi?dobacterium spp., Clostridium coccoides, Ruminococcus albus, Butyrivibrio fibrisolvens, Fusobacterium rausnitzii were sharply decreased (P<0.01). However, the number of Escherichia coli, which belongs to the Enterobacteriacae family, was greatly increased (P<0.05). [Conclusion] The results prove that the population of probiotics decreased, some harmful microorganism quantity increased in the cecum of diarrhea rex rabbit, the cecum flora structure is difference but not significant (P>0.05), indeed the structure of flora has a tendency to complicate in the diarrhea rabbit.

Abstract:[Objective] The possible relationships between glycerol and the extracellular polyphenols (EP) production from Lachnum DP5 were explored initially. [Methods] The influences of various carbon sources, glycerol concentration, kojic acid, inhibitors and precursors on EP production and biomass were investigated. [Results] The EP accumulation was obviously increased by the addition of glycerol. The maximum EP content reached 0.664 g GAE/L when using 20 g/L glycerol as the carbon source. Meanwhile, kojic acid was produced, and its yield was 0.25 g/L. The EP yield increased from 0.209 g GAE/L to 0.376 g GAE/L by the addition of kojic acid into the sucrose-containing medium. The phenoloxidase activity was lower in the fermented glycerol-containing medium than that in the fermented sucrose-containing medium. The EP from Lachnum DP5 was biosynthesized via the shikimate and polyketide pathways. The biosynthesis of precursors of the shikimic acid and polyketide pathways were improved by glycerol. [Conclusion] Glycerol stimulated the biosynthesis of relative precursors and inhibited the bioconversion of polyphenols to melanin. Thus, EP accumulation was boosted by the addition of glycerol as carbon source.

Abstract:[Objective] Streptococcus suis serotype 2 (SS2) is an important zoonotic pathogen, showing high diversity in virulence in different strains. Lacking suitable target(s) has, to date, hindered evaluation of virulence in SS2. Therefore, we investigated the relationship between the genotype of mrp and the virulence of SS2. [Methods] Different genotypes of mrp were identified by PCR; Virulence of SS2 strains was evaluated by internally standardized zebrafish model; and the transcription level of mrp in different strains was evaluated by real time PCR (quantitative PCR, qPCR). [Results] Two genotypes, named mrp-A (27 strains) and mrp-B (26 strains), were identified in 53 SS2 strains. Strains belonged to genotype mrp-A showed stronger virulence and higher transcription level of mrp than mrp-B strains. [Conclusion] mrp was widespread but various in different SS2 strains; and mrp-A strains tended to be highly pathogenic. Furthermore, the non-conservative region of mrp could be a virulence-marker for SS2.

Abstract:[Objective] We focused on finding out the active area of catalytic domain of endolysin Ly7917 against Streptococcus suis, consequently helpful for Ly7917 modification. [Methods] A group peptides truncated from N-terminal of Ly7917 or C-terminal of LyCHAP were expressed and compared with original Ly7917 and LyCHAP of the catalytic activity by plate lysis assay and turbidity decrease assay, even the situation with addition of Ca2+. [Results] LyCHAP showed excellent catalytic activity as well as the full-length Ly7917. Truncated Ly7917 from N-terminal showed no catalytic activity. With the assistance of Ca2+, LyCHAP without 20 amino acids at C-terminal (LyCHAP1?130) could achieve the maximum catalytic effect even better than full-length LyCHAP. [Conclusion] Ca2+-dependent LyCHAP1?130 could be the potential alternative of Ly7917 for further clinic trials.

Abstract:[Objective] This paper aimed to estimate the diversity and characterization of endophytic bacteria isolated from seed of Caragana leucophloea Pojark which good adaptability to desert. [Methods] The methods used in this study include seeds surface sterilization, seed coat and kernel separation, endophytic bacteria isolation, tolerance to pH and NaCl estimating, 16S rRNA gene sequencing and phylogenetic analyzing. [Results] With the thirty-two isolates, six and twenty-six strains were obtained from seed coat and kernel, respectively. The optimal pH for all strains that from seed coat was above pH 9.0 and the maximum was up to 14.0 for three of them, and the tolerance to salt was up to 10% NaCl for five isolates. The tolerance to pH of the strains isolated from kernel was significantly lower than that from seed coat, but there’s twelve strains could tolerant to salt up to 10% NaCl also. According to 16S rRNA gene sequences analysis, thirty strains belong to Bacillus sp. with the similarity between 95%?99%. Among them, thirteen isolates was closed to Bacillus subtilis with similarity 96%?99% and eleven was closed to Bacillus licheniformis with similarity 95%?99%. One strain belong to genus Sphingomonas sp. with the homology of 99%, and one belong to genus Escherichia sp. with the homology of 98%. [Conclusion] The results has showed that the diversity of endophytic bacteria of C. leucophloea’s kernel was higher than that of the coat, indicating their space distribution and species diversity. And we could speculate that the higher tolerance on pH and salt of the bacteria of the seed coat must have some relationship with the host environment adaptability.

Abstract:Dissimilatory nitrate reduction to ammonium (DNRA) of bacteria is a potentially important path of nitrogen cycling in estuarine regions. This paper introduces the mechanisms and types of DNRA, reviews the value and impacts of DNRA, and summarizes the influence of several major environmental factors on DNRA in estuarine regions. Parts of the mechanisms of DNRA still remain unclear. Further studies focusing on the relationship between DNRA and environmental factors, as well as the development of new methods and techniques are suggested, to provide a scientific basis for the protection and restoration of estuarine regions.

Abstract:Staphylococcus aureus is a leading pathogen threatening global public health. Various clinical infections caused by S. aureus are closely related to the expression of many virulence factors. The expression of these virulence factors is precisely regulated by regulatory factors, which have the key role in the pathogenicity of S. aureus. Small non-coding RNAs (sRNAs) are important regulatory factors, which can make S. aureus respond to environmental changes, and regulate the stress and expression of virulence. However, biological functions have only been elucidated for a few of these sRNAs. In this review, we summarize the recent research progress in S. aureus regulatory sRNAs.

Abstract:Peptidoglycan is an essential component of the cell wall of lactic acid bacteria, its chemical structure is mainly conservative and constant, and its biosynthesis is a complex process involving multi-step reactions. Peptidoglycan of lactic acid bacteria exhibits various biological activities, such as immune-enhancing functions, anti-infection, anti-tumor, and anti-anaphylaxis. In this review, the composition, structure and biological activity of peptidoglycan of lactic acid bacteria are outlined, the research development in metabolism and regulation of peptidoglycan is reviewed emphatically, and the direction to the future study of lactic acid bacteria peptidoglycan is proposed as well.

Abstract:With the development of synthetic biology, design and synthesis of functional elements show great potential in assisting and simplifying the study of metabolic engineering. The fundamental level of transcriptional control takes place at promoter elements that drive gene expression. Synthetic promoter library (SPL) provides promoter with different strength for fine-tuned gene expression. SPL is an important solution to optimal expression of gene and combinatorial optimization of metabolic pathways. This review is mainly focused on the current methods and advances in strategies of SPL. Apart from the description of the developments, we discuss the application of artificial promoter in metabolic engineering and research prospect of promoter engineering in the future.

Abstract:Polyoxin is a high effective and broad-spectrum antifungal peptidyl nucleoside antibiotics inhibiting fungal cell wall biosynthesis, as a result, it was used extensively to control phytopathengenic fungi in agriculture. This review summarized the research progress on the chemical structure and physical and chemical properties of this antibiotic, and particularly described recent advance of our lab on the cloning and elucidation of the polyoxin biosynthetic pathway, as well as the combinatorial biosynthesis of this antibiotic. Simultaneously, we also take a brief perspective on the studies on nucleoside antibiotics biosynthesis.

Abstract:The modular teaching pattern has been applied to the experimental teaching of microbiological examination of water. The modular content is composed of three units, i.e., the plate-count of bacteria in water, the total coliforms testing in water and examination of their physiological and biochemical properties, and the serological test of coliforms. The experimental contents are organized based on the national standard examination methods for drinking water-microbiological parameters (GB/T 5750.12-2006). In the teaching process, we emphasize on the standardized modular experimental procedure and operation to raise the undergraduate students’ awareness of standardization. The continuous modular experiments belonged to the hygienically microbiological examination experiments are converted to the basic experiments of bacteria taxonomy, and through which two teaching goals can be achieved. The first is to cultivate the undergraduate students’ experimental ability of microbiological testing, and the second is the students will master the systematic taxonomic identification methods for Escherichia coli. In the module examination, the undergraduate students are required to write a research paper about this module and fill out a report designed with references to a standard test report from a professional testing institution. The reform of the teaching module for microbiological examination of water can improve the students’ research skills in microbiology, specifically in microbial quantitation and bacterial identification, which will be helpful for the undergraduate student to carry out innovative research.

Abstract:According to the specialty aim of normal university and the new curriculum reform of middle school, Research-oriented teaching mode has been performed in the Microbiology teaching. In the process of teaching, it emphasizes the students’ consciousness and abilities of Research-oriented teaching practice training by leading students to experience the teaching contents, teaching methods, research activities and some other aspects. At the same time, in the Microbiology teaching, it strengthens the teacher’s guiding role and the connection with the middle school biology teaching. The teaching practice showed that the Research-oriented teaching mode that combines the Microbiology and the biology in middle school, not only stimulated students’ interest in studying the course, promoted active thinking, but also developed their consciousness and abilities of Research-oriented teaching mode practicing. So it meets the demand of the new curriculum reform of middle school.

Abstract:In this paper, author explore the teaching pattern of microbiological class by teaching effects and evaluation system, based on classroom studying in Benedictine University for two months, as well as communicated and cooperated with microbiological professional teacher. The teaching mode emphasizes the cultivation of students’ comprehensive qualities, pay attention to the inspiration and interest. At the same time, theoretical teaching coordinates with practical teaching and extracurricular scientific activities. The research provides certain reference for microbiology teaching in China.

Abstract:The advent of digital microscope mutual laboratory caused a revolution of teaching methods in morphology. It provided the brand-new teaching idea and a powerful platform for the microbiology experiment teaching. The paper introduces the scientific application of digital microscope mutual laboratory to creating a new information-based teaching environment in microbiology experiment teaching. It is evident that the rational use of digital microscope mutual system has a large impact on improving students’ motivation and subjectivity, and the teaching is high effective.

Abstract:The open optional course is an important part of the personnel training program. Development and Utilization of Microbial Resources and Soil Biology are two open optional courses which are closely related to Microbiology. With the continuous effort to improve the classroom teaching for more than five years, we have formed a set of relatively complete teaching and examination methodology. First, the students can decide whether to choose the course according to their interests and needs by auditioning. Second, most of the course is instructed by teachers systematically by using interactive teaching method, and a part of the course is taught by displaying videos and class discussion. Third, the assessing method and grading standard of presentation would be adjusted and optimized. Moreover, encourage students to read and translate the high-level English literature. Finally, our five-year teaching practice showed that these teaching reformations have effectively improved the teaching quality of open optional courses.