Abstract:[Background] The assembly dynamics of microbial community and its environmental driving forces during liquor solid-state fermentation (SSF) is important for revealing the characteristics of brewing microbes. [Objective] The purpose of this study was to reveal microbial community succession and its environmental driving forces during roasted sesame-flavor liquor SSF. [Methods] The dominant genera and community structure transition were revealed by high-throughput sequencing. The distribution of metabolic pathways in prokaryotic microbial community during SSF was predicted by PICRUSt. The interpretation rate of physicochemical properties to microbial community composition was revealed by correlation analysis. The effect of physicochemical properties on community composition was verified by simulating fermentation under laboratory conditions. [Results] The roasted sesame-flavor liquor SSF process was divided into two stages: At stage I (0?5 d), ethanol and acidity reached the highest synthesis rate and consumption rate while Bacillus and Pichia were the most abundant prokaryotic/eukaryotic genus. Acidity was the key environmental driving force. At stage II (5?30 d), Lactobacillus and Saccharomyces were of highest abundance and ethanol was the key environmental driving force. The interpretation rate of physicochemical properties for microbe’s distribution during SSF was 68.27%. Ethanol and acidity accounted for 13.76% and 4.43% respectively while the combination of ethanol and acidity accounted for 23.17% and had significant synergism on driving community succession. [Conclusion] The study revealed microbial community succession and its environmental driving force, which could help to control the liquor SSF processes effectively.

Abstract:[Background] Based on the sequence analysis of a novel recombinant highly thermostable b-mannanase (ReTMan26) from a thermophilic Bacillus subtilis (TBS2), there are 3 N-glycosylation sites (N8, N26 and N255) in the encoding gene of ReTMan26, and ReTMan26 could be N-glycosylated when expressed by Pichia pastoris. [Objective] To determine the effects of N-glycosylation on the stability of ReTMan26. [Methods] Through constructing the three-dimensional structure models, the effects of N-glycosylation on the stability of ReTMan26 were analyzed. Then, the N-deglycosylated ReTMan26 (ReTMan26-DG) was obtained using Native Protein Deglycosylation Kit. After purification, the differences of enzymatic stability between ReTMan26 and ReTMan26-DG were determined. [Results] The optimum reaction pH of ReTMan26 was 6.0, identical with that of ReTMan26-DG, and pH stability of ReTMan26 was slightly higher than that of ReTMan26-DG in pH range between 1.5 and 9.0. The optimum temperature of ReTMan26 was 60 °C, 5 °C higher than that of ReTMan26-DG. ReTMan26 retained 58.6% of its maximum activity after treatment at 100 °C for 10 min. However, ReTMan26-DG retained 58.2% residual activity after treatment at 93 °C and was completely inactivated after treatment at 100 °C for 10 min. After treatment with trypsin or pepsin at 37 °C for 2 h, ReTMan26 retained 91.2% and 70.5% of its baseline activity, 23.7% and 25.6% higher than ReTMan26-DG, respectively. [Conclusion] N-glycosylation could improve the stability of ReTMan26 at different pH, high-temperature and the resistance to digestive proteases.

Abstract:[Background] The majority of studies on microbial contamination in drinking water focuses on bacteria, viruses, protozoa and worms, but less on fungi. We should also pay attention to fungi that contains a variety of potential pathogenic groups. [Objective] To study the changes in population and community structure of fungi and potential pathogenic fungi that may exist in urban water supply systems. [Methods] Two culture media (MEA and RB) were used to study the raw water, the purified water from two waterworks and the tap water from different secondary water supply modes in water supply systems. The total DNA of the above samples was extracted and the Illumina Miseq platform was used for high-throughput sequencing of the ITS1 gene. [Results] According to the high-throughput sequencing data, 579 470 effective sequences and 1 260 OTUs were obtained from 15 samples. The 228 fungal genera belong to 67 orders, 26 classes, and 8?phylum. The dominance of Ascomycota in water supply systems and fungal genera such as Aspergillus and Acremonium were present in all samples but rest were varied from samples to samples. The results of culture dependent and high-throughput sequencing showed that the population and species richness of fungi rose after filtering by biological activated carbon. Chlorination had a significant effect on the quantity, diversity and community of fungi. After passing through the water distribution systems and secondary water supply facilities, tap water sample showed significantly higher data in the quantity and species richness of fungi than effluent water. [Conclusion] The dominant fungi in the water supply system belong to Ascomycota and the dormant fungal spore can penetrate the multi-stage barriers in the water treatment process. The water purification process can effectively remove culturable fungi from water, and the biological activated carbon filtration process can lead a fungus leakage. Water supply pipelines and secondary water supply facilities are important sources of fungal contamination in drinking water and potentially pathogenic fungi that can cause infections exist in water supply systems.

Abstract:[Background] Plants are inhabited by diverse bacterial endophytes that are closely related to the growth and stress tolerance of their hosts. Bidens pilisa L. is a highly invasive plant species with strong stress tolerance. However, up to date, there is limited literature reporting the research involving the bacterial endophytes of the plant species. [objective] To investigate and characterize the diversity of bacterial endophytes community of B. pilisa, and to obtain the bacterial isolates from the plant species with both potential of heavy metal-tolerance and indoleacetic acid (IAA) production. [Methods] The diversity of bacterial endophytes community was analyzed by using MiSeq high-throughput sequencing method. The tolerance ability to heavy metals Pb, Cd, Ni, and Hg, as well as the IAA-producing ability of bacterial endophytes were evaluated by using culture-dependent method. [Results] We recovered a total of 4 031 distinct operational taxonomic units from the total bacterial endophytes community of B. pilosa, which could be affiliated with 25 distinct bacterial phyla, 51 distinct bacterial classes, 76 distinct bacterial orders, 182 distinct bacterial families, and 536 distinct bacterial genera. At the genus level, the most dominant bacterial genera detected from the root, stem, leaf, and seed of B. pilosam were Enterobacter, Acinetobacter, Sphingomonas, and Pseudomonas, respectively, followed by Burkholderia, Methylobacterium, Pseudomonas, and Pantoea. Using culture-dependent method, we obtained 34 bacterial isolates from the internal tissues of B. pilisa and all obtained strains showed the tolerance at least to one tested heavy metal. Seven strains (numbered GF-1, GF-8, YF-1, YF-2, JF-1, GF-2, JF-8, respectively) could produce IAA with IAA yields varying in the ranging from 57.48?312.22 μg/mL. Based on 16S rRNA gene sequence analysis, the 7 IAA-producing strains were identified, and strains GF-1, GF-8, YF-1, YF-2, JF-1 as Bacillus spp., strain GF-2 as Pseudomonas sp., strain JF-8 as Burkholderia sp. [Conclusion] The bacterial endophytes community of B. pilosa has high population diversity. Bacterial endophytes strains GF-1, GF-8, YF-1, YF-2, JF-1, GF-2, and JF-8 obtained from B. pilosa show not only multi-heavy metals tolerance also high IAA production, being good candidates used as bio-inoculation agent for bioremediation of heavy metal-contaminated soil.

Abstract:[Background] Strains of Rhizopus arrhizus vary in physiological and biochemical indicators, but relative genetic background is unclear, hindering their further applications in fermentation. [Objective] This study explored temperature-growth kinetic models among strains of R. arrhizus in order to lay a foundation for investigating population genetics and for screening materials potential in production. [Methods] R. arrhizus isolated from Asia and Europe were first identified by morphology and then by molecular phylogeny reconstructed with ITS and IGS rDNA. Finally, their temperature-growth kinetics was analyzed by directly measuring colonial diameters on medium plates. [Results] The temperature-growth kinetic models of R. arrhizus were diverse, and the curves significantly differ, with less relatedness to morphological and phylogenetic varieties. Lower restraining growth, optimum growth, higher restraining growth, and fatal temperatures were 4?9, 30?37, 40?49, and 40?52 °C, respectively. Strains XY00454 and XY00469 grew rapidly and adapted well to higher temperatures and therefore were potential for industrial production. [Conclusion] R. arrhizus is still evolving violently and diverging actively in morphology, molecular and physiology, while not developing any independent populations. It is feasible to screen fermentation potential isolates based on thermal adaptability.

Abstract:[Background] River confluences have become a focus in ecological management of a river basin. [Objective] The microbial community structure and main influencing environmental factors at the estuary of the Fenhe River into the Yellow River were studied. [Methods] The microbial community structure at estuary of the Fenhe River into the Yellow River in summer was analyzed by means of 16S rRNA gene-based Illumina Miseq high-throughput sequencing, and the main environmental factors affecting the microbial community were identified by canonical correspondence analysis. [Results] The alpha-diversity analysis revealed that the diversity of microbial community was high in this area. Microbial diversity analysis indicated that the dominant bacterial phyla were Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria; at genus level of taxonomic criteria, the dominant genus was Bacillus, followed by Lactococcus and hgcI_clade. Spearman correlation analysis and canonical correspondence analysis (CCA) showed that environmental factors had significant effects on the microbial community structure of water. [Conclusion] The microbial community composition was different between the Fenhe River and the Yellow River, different environmental factors had distinct effects on diverse microorganisms. The microbial communities were mostly affected by pH and dissolved oxygen (DO) at the estuary of the Fenhe River into the Yellow River.

Abstract:[Background] Bacterial diversity plays an important role in the ecological function of green space soil. However, there is no report on the soil bacterial diversity of urban parks at different age. [Objective] In order to study soil bacterial community diversity and structure characters. [Methods] Illumina Miseq sequencing was adopted to analyze soil bacterial community structures of typical old and young urban parks in Beijing. [Results] The results showed that 45 known phylum were found, among them, Acidobacteria, Proteobacteria, Chloroflexi and Actinobacteria were dominant bacterial groups in all soil samples. Alpha diversity analysis showed that there was a significant differentiation on soil bacterial diversity. The richness and diversity of soil bacterial community in old parks were higher than that of young parks. In addition, similarities analysis and principle coordinate analysis indicated that there was a significant differentiation in bacterial community structure between old and young parks. The redundancy analysis of soil microbial community structure and environmental factors showed that soil moisture, soil organic matter and total nitrogen were the key determinants influencing the soil microbial community structure, whereas none of the soil properties was found responsible for the changes in the soil bacterial community structure. [Conclusion] This study introduced the park age as an influencing factor for redundancy analysis. The results showed that park age is an important factor affecting the diversity of the bacterial communities in the urban parks.

Abstract:[Background] Saccharomyces cerevisiae is widely used to produce valuable proteins such as pharmaceutical proteins and industrial enzymes, but the low protein production and secretion level are challenging for efficient production of heterologous proteins. Synthesis of heterologous proteins and their secretion may produce a variety of stresses to host cells, thereby inhibit the production efficiency. Therefore, studying the effects of stress responsive genes on heterologous protein production is of great significance. Mhf1p is one of the components of MHF histone folding complex, and involved in repairing damaged DNA and maintenance of genome stability, but its role in the production of heterologous proteins remains unclear. [Objective] To study whether MHF1 overexpression can promote protein production in the recombinant S. cerevisiae. [Methods] MHF1 was overexpressed by chromosomal integration in the recombinant S. cerevisiae strains producing different cellulases employing CRISPR-Cas9 based genome editing, and cellulases secretion was compared with that of the control strain. Furthermore, the underlying molecular mechanisms were explored. [Results] Compared with that of the control strain, cellobiohydrolase (CBH) activity in the MHF1 overexpressing strain was increased by 38%. Transcription levels of key genes such as genes related to protein production and secretion of the yeast strains were further detected. Comparing with that of the parent strain, elevated transcription levels of CBH1, as well as key genes related to protein secretion such as SEC22 and ERV29 in different time points were revealed by overexpression of MHF1. [Conclusion] Overexpression of MHF1 promoted the production of a heterologous cellobiohydrolase in S. cerevisiae. Enhanced transcription of CBH1 and genes involved in secretion pathway was revealed, indicating that MHF1 modulates heterologous protein production by synergistic regulation of multiple genes.

Abstract:[Background] Meloidogyne incognita has a wide range of hosts to infect including Solanaceae, Leguminosae, Cucurbitaceae and other vegetables. It causes serious damage and tens of billions of losses to the global agricultural production every year. Bacillus cereus AR156 is a gram-positive and rod-shaped bacterium that can be used as a biocontrol agent to control M. incognita, and has complete genome-wide sequencing. [Objective] In order to understand its biocontrol mechanism against M. incognita and to search for the related gene of biocontrol function, we analyzed the functional gene of B. cereus AR156. [Methods] We screened mortality of M. incognita and biocontrol efficiency under greenhouse in the AR156 miniTn10 random insertion transposon library to find mutants associated with biocontrol ability in AR156. Gene involved in biocontrol in AR156 was identified. And we compared producing-protease ability, colonization, biofilm formation and swarming motility. [Results] Compared with the AR156 wild-type, BC41 had reduced production of protease, colonization of plant rhizosphere, formation of biofilm and swarming motility. Its insertion site is the M60 family peptidase, which decreased the ability to biocontrol M. incognita. [Conclusion] M60 family peptidase plays an important role in the biocontrol activity of B. cereus AR156 by the analysis of biocontrol-related functional gene.

Abstract:[Background] Bacterial cellulose is a new type of natural bio-nanomaterials with excellent properties, but it has not yet been achieved production and application in large-scale because of the low fermentation yield and high production cost. [Objective] We naturally selected and bred cellulose high-yield strains, and explored the relationship between the strain yield, colony morphology, fruits source and strains species. [Methods] Naturally bred cellulose-producing strains were selected from a total of 576 rotten fruits covering 15 species, and classified by colony morphologies. High-yield cellulose strains were screened by static culture, and the 16S rRNA gene region of the strains was sequenced to identify their species. [Results] 134 cellulose-producing strains were obtained. The best strain Komagataeibacter hansenii was isolated from mango with the yield 11.24 g/L. All strains was classified into 10 categories according to the colony morphology. The common characteristics of high-yield cellulose colonial morphologies were yellow, round, raised, neat or irregular edges and rough or wrinkled surface (morphology 4, 5, 9). The colonies’ morphological diversity of strains isolated from apple and pear were abundant. Most of high-yield cellulose strains were mango-derived, followed by pears and apples. All strains were identified as 5 genera and 13 species, including Acetobacter, Komagataeibacter, Gluconacetobacter, Serratia, and Lactobacillus, in which highly productive cellulose strains were concentrated in K. hansenii and K. intermedius. [Conclusion] The screened strains are rich in diversity, and a number of high-yield cellulose strains are obtained, which have good heredity stability and greatly enrich the source of bacterial cellulose production strains. Analysis of the relationship between the yield of the obtained strains with the colony morphology and fruit source may offers reference for future screening work.

Abstract:[Background] Polysaccharide is one of the main substances in Hericium erinaceus and is commonly used in the treatment of neurasthenia, tumors, and digestive diseases like gastritis and ulcers. At present, studies on polysaccharides from H. erinaceus mainly focus on the structural analysis, but few on the effects of different substrates on the physicochemical properties of polysaccharides from the fruit bodies. [Objective] The physicochemical properties and in vitro immune activity of polysaccharides from fruit bodies of H. erinaceus cultivated on different substrates were studied to select the better cultivation formula of H. erinaceus with high yield and good quality. [Methods] Different fruiting bodies of H. erinaceus were obtained by industrial cultivation with seven different formulations of substrates. The yield of fruit bodies and the content of crude polysaccharides were analyzed and determined. The physicochemical characteristics such as molecular weight distribution and monosaccharide composition of the polysaccharides of H. erinaceus fruiting bodies obtained from seven different substrate cultures were analyzed, and the differences in NO release from RAW264.7 macrophage cell strains were compared. [Results] All indicators showed that the formula 2 (sawdust 30%, corncob 40%, cottonseed shell 15%, corn flour 2%, wheat bran 6%, rice bran 5%, gypsum 1%, lime 1%) and formula 7 (corn cob 39%, cottonseed shells 10%, wheat bran 10%, rice bran 30%, soybean bran 5%, beet residue 4%, calcium carbonate 2%) can be considered as excellent, efficient and high quality cultivation compared with other formulations of culture substrates. [Conclusion] The selected culture formulas are suitable for the cultivation fruiting body of the deep processed raw materials for H. erinaceus.

Abstract:[Background] Riemerella anatipestifer causes septicemic and exudative diseases of domestic ducks, gooses and turkeys, leading to economically devastating to poultry industries. A total of 21 serotypes of R. anatipestifer have been identified. Moreover, there is poor cross-protection among these serotypes. Lipopolysaccharide is the important component of outer membrane of Gram-negative bacteria, and provides the diversity of bacterial surface antigen determinants. [Objective] To prepare and characterize monoclonal antibodies (McAbs) against lipopolysaccharide of R. anatipestifer serotype 2 strain. [Methods] BALB/c mice were immunized with inactivated R. anatipestifer serotype 2 strain NJ3. Spleen cells from immunized mice were fused with murine myeloma SP2/0 cells. The hybridoma cell line that stably secret McAb against LPS of R. anatipestifer serotype 2 strain, was obtained through clone selection and screening by indirect enzyme linked immunosorbent assay (ELISA). The mouse ascites was prepared and identified by Western blot analysis and ELISA. The specificity of these McAbs was tested by slide agglutination assay and Western blot. [Results] We successfully obtained 2 hybridoma cell lines named 8G5 and 8G10 that could stably produce anti-LPS McAbs. The isotype of both McAbs was identified as IgM with κ light chain. The titers of 8G5 and 8G10 were 1:32 000 and 1:16 000, respectively. Western blot results showed that both McAbs specifically reacted with R. anatipestifer serotype 2 strains but did not react with R. anatipestifer other serotypes strains, avian pathogenic Escherichia coli, Salmonella enterica and Pasteurella multocida strains. [Conclusion] We prepared two specific anti-LPS McAbs that can be used for pathogenic mechanism research and development of rapid detection of R. anatipestifer serotype 2 strains.

Abstract:[Background] Individuals adjust their nutrition absorption and energy metabolism when exposing to hypobaric hypoxia. Gut microbiota performs essential functions for host physiology, including digestive, metabolic, and immune mechanisms. However, little is known about the dynamic composition of gut microbiota as well as metabolic function during host acclimatized to hypobaric hypoxia. [Objective] To characterize and compare the gut microbiota of SD rats during 1, 7, 14, 21 and 28 days after being exposed to a simulated altitude of 4 500 m (hypobaric chamber) with control groups (43.5 m). [Methods] We studied fecal samples by Illumina HiSeq platform targeting the V3?V4 region of the 16S rRNA gene. Sequences were processed using the QIIME software package, UPARSE pipeline. LEfSe analysis was used to determine the different species between groups. The functional profiles of microbial communities were predicted by using PICRUSt. [Results] Fecal microbiota analysis revealed that the hypoxic exposure caused distinctive gut microbiota in rats, compared to the control groups. We detected the overrepresentation of Bacteroidetes, Bacteroidales, Bacteroidaceae, Prevotellaceae, Prevotella, copri and underrepresentation of Ruminococcaceae, Ruminococcus, Clostridia and Clostridiales in hypoxic exposure rats’feces. PICRUSt analysis revealed that Genetic Information Processing and metabolic related pathways were enriched in the hypoxic exposure groups than those in the control groups. [Conclusion] Hypoxic exposure caused dramatic changes of the structure, diversity and predicted function of gut microbiota in rats. The relative abundance of gut microbiota with complex glycan depolymerisation were enriched after hypoxic exposure. Those may involve in host adjustment of metabolism, and could be beneficial for host acclimatized to hypobaric hypoxia.

Abstract:[Background] Cordyceps militaris is one of the famous medicinal fungi. Carotenoid is not only an important active component but also affects the appearance of fruiting body. However, the factors regulating its production are unknown. [Objective] To reveal the effects of nitrogen sources on the growth and carotenoid production of C. militaris. [Methods] The growth rate, conidia and carotenoid production on media with different nitrogen sources were determined and the optimum nitrogen sources were selected. The effects of nitrogen concentration on carotenoid production of C. militaris fruiting body under different light conditions were further determined. [Results] There were significant differences in growth and carotenoid production of C. militaris on media with different nitrogen sources. The growth rate was the fastest in wheat bran and soybean powder media, showing as fluorescent yellow and very weak red, respectively. The conidia produced in peptone and yeast extract media were significantly more than that in other nitrogen sources (P<0.01), and the colony was orange. There was no pigment production in inorganic nitrogen source media except for trace pigments on the back of plate of glutamic acid and ammonium chloride. It was found that the carotenoid content increased with the increase of peptone concentration in the range of 0?3%. Blue light was more suitable for the carotenoid production in fruiting body than white light. The carotenoid contents were the highest with the peptone concentration of 1% under both white and blue light conditions, 2 809.38±386.24 μg/g and 4 093.75±518.37 μg/g respectively. [Conclusion] Nitrogen source and its concentration significantly affected the carotenoid production in C. militaris. Blue light and peptone concentration of 1% were the best conditions for carotenoid production in fruiting bodies. This study will be helpful for cultivating C. militaris fruiting body rich in carotenoid.

Abstract:[Background] The IncFII-FIA-FIB incompatibility group plasmids are widely encountered in Enterobacteriaceae species. They mediate the horizontal transfer of many resistance genes and lead to the upsurge of multidrug-resistant strains. [Objective] To investigate the genomic characterization of the multidrug-resistant plasmid pBTR-CTXM assigned into IncFII-FIA-FIB incompatibility group and the plasmid-mediated horizontal transfer mechanism of resistance genes of Escherichia coli BTR. [Methods] The screening of antibiotic resistance genes was determined using PCR. The transferability of plasmid pBTR-CTXM was confirmed by conjugation experiments and electroporation experiments. The minimal inhibitory concentration (MIC) values were tested by VITEK 2 Compact system. The complete nucleotide sequence of pBTR-CTXM was determined using next-generation sequencing technology from a mate pair library. Structural genomics of pBTR-CTXM was analyzed subsequently. [Results] The multidrug-resistant E. coli BTR isolate harbored the blaNDM-1, blaCTX-M-15, blaTEM, qnrD, qnrS1, mph(A), erm(B), and tetA(B) genes. The blaCTX-M-15, mph(A), erm(B), and tetA(B) genes were located on pBTR-CTXM (GenBank accession number MF156697) with 144 939 bp in length. The pBTR-CTXM could be conjugatively mobilized to the recipient strain E. coli EC600 by pNDM-BTR, a conjugative plasmid existed in the E. coli BTR. pBTR-CTXM possessed typical backbones of IncFII-FIA-FIB plasmids and a multidrug-resistant (MDR) region, which was comprised of a novel composite transposon Tn6492, the Tn2 remnant, the Tn10 remnant, the ISEcp1-blaCTX-M-15-Δorf477 unit and some insertion sequences (IS) elements. [Conclusion] The novel composite transposon Tn6492, the Tn10 remnant, and the ISEcp1-blaCTX-M-15-Δorf477 unit mediated the horizontal transfer of resistance genes and the antibiotic resistance of E. coli BTR.

Abstract:[Background] Excessive gestational weight gain among women has increased dramatically worldwide, which is associated with maternal and infants’ health. Recent evidence supports that gut microbiota may be an important regulation factor correlated with numerous human diseases. [Objective] To explore maternal gut microbiota diversity and composition at late pregnancy and changes of maternal gut microbiota with different gestational weight gain status, evaluating the effect of gestational weight gain on maternal gut microbiota. [Methods] we collected 62 pregnant women’s fecal samples at late pregnancy (36.82±2.19 gestation weeks), using high-throughput Miseq sequencing technology for sequencing 16S rRNA gene sequence in the V3?V4 region of samples. [Results] maternal gut microbiota of excessive gestational weight gain has a significantly lower diversity. The most important five genus of gestational weight gain are Alistipes spp., Eubacterium-nodatum group spp., Oxalobacter spp., Raoultella spp. and Odoribacter spp. And the intensity of correlation of Alistipes spp. is the most strong and abundant. There are no differences between adequate and excessive groups in gut microbiota structure. [Conclusion] Gestational weight gain can affect maternal gut microbiota at late pregnancy and the balance of gut microbiota will stimulate a healthy development of maternal and infants.

Abstract:Polycyclic aromatic hydrocarbons are a group of refractory organic compounds well known for their carcinogenesis, teratogenesis and mutagenesis. This review summarizes recent degradative patterns based on investigations on worldwide polycyclic aromatic hydrocarbons contamination in aquatic sediments, in which microbial respiration couples polycyclic aromatic hydrocarbons degradation by using nitrate, Fe(III) and sulfate as electron acceptors. In addition, polycyclic aromatic hydrocarbons degradation-related genome, proteome, and metabolomics of microbial organism as well as community interactive networks, are also involved so as to further complement the theory of in-situ bioremediation of polycyclic aromatic hydrocarbons contaminated sediments.

Abstract:Polyene macrolide antibiotics, as effective antifungal agents, are widely used in the treatment of fungal infections, food preservatives and agricultural aspects. With the development of next-generation sequencing technology and bioinformation, numerous antibiotic biosynthetic gene clusters of Streptomyces have been identified. A variety of regulators encoded by regulatory genes play a crucial role in the regulatory network of Streptomyces. This article summarizes the important types of regulatory factors of Streptomyces and reviews the progress of regulatory factors of the biosynthetic gene cluster of polyene macrolide antibiotics. Combining with the functions of regulatory factors, structural binding site and regulatory mechanisms, the potential relationship and research are summarized and prospected.

Abstract:In mushroom cultivation industry, Trichoderma spp. not only pollutes the mushroom substrate but also infects mycelia and fruiting bodies causing a dramatic loss in economy. In this paper, the morphology characteristics and biochemistry basis of the interaction mechanism between Trichoderma spp. and edible fungi are summarized, the research advances of the disease resistance inheritance and mechanism on edible fungi are discussed, and the problems of the interaction mechanism between the host and pathogens that should be researched in the future are suggested.

Abstract:Modern informational social calls for the new pattern of microbiological experiment teaching reform. The microbiology experiment teaching of cultivating students’ innovative ability is fully implemented. Based on the characteristics of students’ personality, academic performance, and hobbies, etc., refined and individualized groups were built before the class. Moreover, The main network of modern information teaching technology such as Classroom, Micro Tas, Rain Classroom, UMU and Optimization of Master Class were introduced in the Microbiology Experiment teaching and carried out for one-year pilot reform. According to the individualized characteristics of the students, five mainstream teaching platforms were carried out in the teaching of five different “Microbiology Experiment” groups. The results of the reform showed that the blended interactive teaching with refinement, individuation and network, which could promote the transformation from “qualitative analysis” to “precision quantitative analysis”. Students were deeply aware that individualized practical learning with the elaboration of teaching methods and tools had more advantages. The learning interest was stimulated and learning effect were promoted as well as comprehensive innovation ability of microbiology experiment was improved in students.

Abstract:Experimental examination is an important component of the independent course of Environmental Microbiology Experiment, which will provide effective guarantee for improving the teaching quality and talent training. In this study, we focused on undergraduates comprehensive capability development and evaluation, a diversified and multi-phase experimental assessment system was established around the network preview examination, class performance of fundamental experiment, and practical ability evaluation of self-designed experiment based on the characteristics of Environmental Microbiology Experiment course. The specific plans and effects were also discussed together, the results of this study will give new insights into understanding the beneficial backwash effect in the aspects of promoting the teaching quality, arousing undergraduate learning interests and improving comprehensive quality, practical ability and innovative spirit.

Abstract:[Background] The stable RNA reference material without biohazard to improve the accuracy and reliability of the detection result, is urgently needed for hepatitis A virus (HAV) detection in food. [Objective] To construct armored RNA reference material containing target RNA of HAV (HAV armored RNA, AR-HAV) based on Qβ bacteriophage, and to test its homogeneity, valuation and stability. [Methods] DNA fragment named QGBHAV containing matures coding gene, capsid protein coding gene, packing site of Qβ bacteriophage, and detection target sequence of HAV in GB/T 22287-2008 was synthesized, and subcloned into pET-28a(+) expression vector to construct the recombinant plasmid pET-QGBHAV, and then transformed into Escherichia coli BL21(DE3) competent cells and expressed with isopropyl-β-thiogalactopyranoside (IPTG) induction. The expression product, virus like particles of Qβ bacteriophage containing RNA of HAV, named AR-HAV, was analyzed by SDS-PAGE. AR-HAV was centrifuged and purified by CsCl density gradient ultracentrifugation and Sephacry molecular sieve chromatography. The morphology of AR-HAV was observed by transmission electron microscopy. The valuation, homogeneity and stability of AR-HAV were tested according to the GB/T 15000.3-2008. [Results] SDS-PAGE analysis showed that the molecular mass of the expressed protein was about 14.1 kD. The virus like particles of AR-HAV, 25 nm in diameter, with typical morphology could be observed under electron microscope. AR-HAV samples prepared in this study had no other proteins nor recombinant plasmid DNA residual contamination, were valued as (2.57±0.12)×107 copies/μL and behaved well in the homogeneity test, F=1.23