Abstract:[Objective] We studied calcium-associated signal responses of Penicillium chrysogenum to phenoxyacetic acid. [Methods] The effects of different types of Ca2+ interference agents (Nifedipine, EGTA, Suramin and Neomycin sulfate) for penicillin V production were studied. Intracellular Ca2+ concentration was measured by Olympus System microscope and SpectraMax M2 Fluorescence Microplate Reader. [Results] Levels of intracellular Ca2+ in P. chrysogenum significantly increased (49.86% higher than the control) at 25 h after treatment with phenoxyacetic acid (POA), whereas significantly reduced (53.31% lower than the control) after treatment with neomycin sulfate as an intracellular calcium inhibitor. Results indicate that cells regulated intracellular calcium level though Ins(1,4,5)P3 signaling pathways to response POA stress. [Conclusion] Understanding the effect of Ca2+ signal transduction pathway how P. chrysogenum responses to POA stress provides guidance for industrial penicillin production.

Abstract:[Objective] To optimize the fermentation conditions of Streptomyces strain MY0504 from marine environment and improve the fibrinolytic activity in fermentation broth. [Methods] Based on the growth curve of MY0504 and single factor test, the main factors affecting enzyme activity were found through the Plackett-Burman design, and the fermentation conditions were further optimized using steepest ascent experiment and Box-Behnken central composite design. [Results] The optimal fermentation conditions were as follows: glucose 21.68 g/L, yeast powder 25.31 g/L, NaCl 5.0 g/L, K2HPO4·3H2O 3.0 g/L, MgSO4·7H2O 0.5 g/L, FeSO4·7H2O 0.02 g/L, medium volume 50 mL (250 mL flask), inoculum size 10% (V/V), initial pH 7.5, fermentation temperature 24 °C, shaking speed 200 r/min, fermentation time 4.5 d. The enzyme activity reached 2 190.6 U/mL in fermentation broth. [Conclusion] The optimal fermentation conditions of strain MY0504 producing fibrinolytic enzyme were obtained, which lay a foundation for further purification and characterization of the fibrinolytic enzyme.

Abstract:[Objective] Inorganic nitrogens (ammonium, nitrate and nitrite) existed simultaneously in complicated mariculture water. This work aims to explore the effects of organic carbons, especially seaweed oligosaccharides on the removal of inorganic nitrogens by a marine purple sulfur bacterium Marichramatium gracile YL28, which is capable of growth on nitrite as sole nitrogen source. [Methods] Sodium hypobromite oxidation, N-(1-naphthyl)-1,2-diaminoethane dihydrochloride spectrophotometry, and UV spectrophotometry were used for the determination of ammonia, nitrite and nitrate, respectively. Biomass was measured by turbidimetry. [Results] Under anaerobic light condition, organic acid salts (acetate, pyruvate, succinate, citrate) were better carbon sources for YL28, and the removal rate of ammonia, nitrate and nitrite reached 97.92%, 99.98%, and 73.23%?87.15%, respectively. Monosaccharides (glucose and fructose), disaccharides (sucrose and maltose) and oligosaccharides (chito-oligosaccharide and seaweed oligosaccharides) were also suitable for YL28 growth. The remove rate of nitrite and nitrate reached more than 99% and 87%, respectively. While the remove rate of ammonia was 44.82%?54.53%. YL28 had poor growth when polysaccharides (alginate, β-cyclodextrin, starch, xanthan gum, carrageenan and agar) as carbon sources. Yeast extract is favorable for YL28 growth, but it severely inhibited the removal of ammonia. Interestingly, the cell growth and inorganic nitrogen removal in combination of poor and good carbon source systems was equally well to that in good carbon source system. The combination of seaweed oligosaccharides and acetate sodium or yeast extract and acetate sodium promoted the increasing growth rate and biomass, however, there was a significantly different in removal rate of ammonium, seaweed oligosaccharides promoted the removal rate of ammonia, while yeast extract not. Under anaerobic dark condition, when using sodium acetate and ammonia as sole carbon or nitrogen source, YL28 grew poorly. However, under coexisting inorganic nitrogen environment, YL28 not only grew well but also removed efficiently inorganic nitrogen. [Conclusion] In coexisting inorganic nitrogen environment, whatever anaerobically in the light or dark, YL28 grows well and has better removal capacity to inorganic nitrogen. Organic acid salts are better carbon sources, sodium acetate is most suitable carbon source. The combination of seaweed oligosaccharides and sodium acetate could significantly promote cell growth and removal of inorganic nitrogen. This study provides valuable information for the development of higher efficiency water cleaner for sustainable mariculture.

Abstract:[Objective] Reconstituted tobacco technology has been one important method to treat and reuse the tobacco waste, in which nicotine control is a key problem to resolve. To realize the flexible control of nicotine, tobacco waste extract (TWE) was selected to screen high activity nicotine degrading strains for potential utilization in reconstituted tobacco process. [Methods] BSM containing nicotine as sole carbon and nitrogen source was used to screen nicotine degrading strains from TWE. Isolated strain identification includes morphology, physiology, and 16S rRNA gene sequence analysis. The activity of nicotine degradation of the isolate was evaluated in BSM and TWE respectively. [Results] The isolate Pseudomonas sp. JY-Q showed high degrading activity and tolerance of nicotine both in BSM and TWE. [Conclusion] Pseudomonas sp. JY-Q is a potential strain for nicotine degradation in aqueous environment and TWE. However, coexisting glucose inhibits its activity, which requires further research to resolve.

Abstract:[Objective] To reveal the phenotypic and gene expression change of Escherichia coli after exposure to microgravity. [Methods] Rotary cell culture system (RCCS) was used to simulate microgravity environment. The effect of microgravity on E. coli K12 was estimated by measuring the growth kinetics, acid resistance and biofilm formation. RNA-Seq was applied to detect the change of gene expression under low shear modeled microgravity (LSMMG). [Results] LSMMG weakened the growth and acid resistance of E. coli K12 and strengthened the biofilm formation ability. Twenty of 25 genes related to nutrition metabolism and the only two acid resistance related genes were down regulated under LSMMG condition. [Conclusion] Simulated microgravity would lead to a certain change of phenotype and corresponding genes. The enhanced biofilm formation and cytotoxicity would be the potential threats of space flight.

Abstract:[Objective] In order to explore whether replication initiation protein (Rep) can be used as a molecular biomarker for the phylogenetic relationship study of natural plasmids. [Methods] The Reps of natural plasmids of Lactobacillus plantarum as a target, the phylogenetic relationships of these plasmids were analyzed and discussed in detail by constructing Rep phylogenetic tree. [Results] A total of 45 plasmids encoding Rep in Lactobacillus plantarum could be clustered into 5 closely related families and 1 single plasmid pG6302, of which family 1 to 4 plasmids could be further subdivided into 10 subfamily groups with closer evolutionary relationships, suggesting that these plasmids may originate from the 6 ancestral plasmids. [Conclusion] Since the amino acid sequences of Reps show suitable conservation and variability, it may be an ideal molecular biomarker for phylogenetic relationship study of plasmids encoding Rep in Lactobacillus plantarum. The results could provide a simple and effective method and standard, as well as the evidence and basis at the molecular level for phylogenetic evolution study of natural plasmids encoding Rep in Lactobacillus plantarum or other lactic acid bacteria.

Abstract:[Objective] A thermostable acetyl xylan esterase (Axe) was identified from a thermophilic bacterium Caldicellulosiruptor sp. F32. [Methods] Based on genome annotation, protein blast, and protein structural prediction, a family-7 carbohydrate esterase (Axe7) was found. After gene cloning, plasmid construction, protein expression and purification in Escherichia coli, the recombinant protein Axe7 was produced. [Results] On the substrate of 4-Methylumbelliferyl-acetate (4-MUA), the optimal pH of Axe7 was between 6.5 and 7.0, the optimal temperature was 85 °C, and the half-life of Axe7 under the optimal condition was more than 4 hours. By incubation with 1.5 mmol/L different metal ions, the retained activities of Axe7 were between (66.3±4.6)% and (95.7±2.3)%, suggesting the effect of metal ions on enzyme activity. The results of enzyme kinetics showed that the Km of Axe7 was 0.39 mmol/L and kcat was 66.95 s?1. [Conclusion] Our findings provide a potential enzyme for the biorefinery industry.

Abstract:[Objective] Gene cloning and codon optimization of the feruloyl esterase from Aspergillus niger (AnfaeA) for its inducible expression in Pichia pastoris X-33. [Methods] The AnfaeA gene was amplified by overlap extension PCR using the genome of A. niger as template. At the same time, the AnfaeA gene was optimized by ‘one amino acid one codon’ and ‘codon randomization’ and then synthesized. The three kinds of ferulic acid esterase gene were cloned into the expression vector pPICZαA, respectively, obtaining the recombinant expression vectors pPICZαA-AnfaeA, pPICZαA-opAnfaeA I and pPICZαA-opAnfFaeA II. The plasmids were then linearized by Sac I, and transformed into P. pastoris X-33. The positive transformants of each gene type were identified by PCR, and further screened by determination of feruloyl esterase activity in fermentations using high performance liquid chromatography (HPLC). [Results] The feruloyl esterase activity of FaeA-ori, FaeA-opt I and FaeA-opt II were 6.8±0.1 U/mL, 5.2±0.1 U/mL, and 39.9±0.1 U/mL, respectively. By ‘codon randomization’ optimization, the activity of recombinant enzyme was 6 times higher than that coded by original AnfaeA gene. However, the feruloyl esterase coded by ‘one amino acid one codon’ optimized gene was only 76.5% of the original enzyme. The optimal temperature and pH for recombinant AnfaeA (reAnfaeA) was 50 °C and 5.5，respectively．In addition, reAnfaeA showed stability when incubated in 45?50 °C and pH 4.5?7.0. [Conclusions] By ‘codon randomization’ optimization, the resultant recombinant feruloyl esterase expressed in P. pastoris X-33 was 6 times higher than that coded by original AnfaeA, reaching the highest activity among existed recombinant feruloyl esterase until now. The results provided large-scale application potential of feruloyl esterase in industrial, and laid the experimental foundation for the further improvement the enzyme activity.

Abstract:[Objective] The alginate lyase gene of Pseudoalteromonas sp. BYS-2 was cloned and expressed in Escherichia coli, and the properties of recombinase were characterized. [Methods] The alginate lyase gene alg738 was cloned from the genomic DNA of Pseudoalteromonas sp. BYS-2 and the recombinant strain BL21(DE3)/pET22b-alg738 was constructed. The recombinase was purified with Ni-NTA resin and the enzymatic properties were studied. [Results] The optimum pH of recombinase was 8.0. It was stable in the pH range of 6.0 to 9.0 and could maintain more than 84% of its relative enzyme activity after incubation at 37 °C for 1 hour. The optimum temperature of recombinase was 45 °C and 66.6% of enzyme activity was remained after incubation at 37 °C for 60 minutes. At the concentration of 5 mmol/L, Na+, Mg2+ and Mn2+ had significant stimulation on the enzyme activity, while Ni2+, Co2+, Cu2+, Hg2+, Zn2+, EDTA, β-mercaptoethanol and SDS had inhibitory effects on the enzyme. The kinetic parameters Km and Vmax of rAlg738 were 1.11 g/L and 0.011 g/(L·min), respectively. Moreover, this recombinase was a bifunctional enzyme which prefers sodium polymannuronate (Poly M). [Conclusion] The properties of the recombinase rAlg738 has laid a good foundation for its future development and application.

Abstract:[Objective] The study was conducted to identify the composition of rhizosphere bacterial communities of Narcissus tazetta and their interaction with growth properties of Narcissus. [Methods] Rhizosphere soil samples of healthy Chongming Narcisuss and Zhangzhou Narcisuss were collected separately. Then, 16S rRNA gene amplification and high-throughput sequencing were used to compare the rhizosphere bacterial composition and diversities of two samples. [Results] The main 12 categories of rhizosphere bacteria of Chongming Narcisuss and Zhangzhou Narcisuss are similar. Proteobacteria, Chloroflexi, Bacteroidetes, Acidobacteria are dominant in the rhizosphere soil of Zhangzhou Narcissus and Chongming Narcissus. However, specific rhizosphere bacterial communities were also found for Zhangzhou Narcissus and Chongming Narcissus based on Venn and PCA analyses. There are more Planctomycetales, Xanthomonadales in rhizosphere soil of Chongming Narcissus while more Chloroflexales, Chlorobiales of Zhangzhou Narcissus. [Conclusions] The composition of rhizosphere bacterial communities may be closely related to the growth properties. The diversity and richness of the rhizosphere bacterial, such as anaerobic ammonium oxidation, opportunistic pathogens and photosynthetic bacteria, could have a crucial influence on growth properties of Narcissus.

Abstract:[Objective] To study the structural diversity of the fungal communities on the surface of fresh citrus peel, with an aim to establish foundation for exploring the changes of the fungal community when the citrus peel became the citri reticulatae pericarpium (CRP) during storage and aging. [Methods] The fresh citrus peel from the Citrus cultivar –Citrus reticulata ‘Chachi’ and Citrus reticulata ‘Dahongpao’ was collected from 5 main citrus origins, namely, Guangdong, Sichuan, Guangxi, Jiangxi, and Chongqing. The fungal internal transcribed spacer (ITS) domain on the citrus peel surface was amplified on the Illumina HiSeq platform for high-throughout sequencing for the first time, the species annotations and abundance of the fungi were analyzed, and the structural composition of the fungal communities was analyzed based on the analysis of Alpha & Beta diversity. [Results] The effective sequences of the 8 citrus peel samples could be classified into 35 genera. The fungal communities on the citrus peel surface of cultivars like ‘Chachi’ and ‘Dahongpao’ with various origins were consistently made up of 7 genera, among which, Erythrobasidium, Penicillium, Aspergillus, Rhodotorula, Mycosphaerella were the top 5 genera in terms of the maximum relative abundance. In addition, it was the first time to discover Aureobasidium and Ramichloridium on citrus peel surface. [Conclusion] This research had determined the structural composition of the citrus peel surface fungal communities, which had established foundation for the correlation research on the fungal community changes and the quality changes of the crude medicine during the storage of citrus peel.

Abstract:[Objective] To isolate and screen antagonistic strains with strongly inhibitory activity on Rhizoctonia solani (Linum usitatissimum L.) from the rhizosphere soil of healthy flax. [Methods] Antagonistic strains were screened out through plate coating and dual culture method. Strains were identified by morphological, physiological and biochemical characteristics and 16S rRNA gene sequence analysis and their biocontrol effect were determined by greenhouse experiment. The fermentation condition was optimized by single factor and Uniform design experiment. [Results] Strain HXP-5 showed strongly inhibitory activity on R. solani (Linum usitatissimum L.) and also antagonistic?effect against other seven phytopathogens. Strain HXP-5 was identified as Bacillus subtilis. Greenhouse experiment showed that the control efficiency were 71.22%. The optimized culture conditions produced antimicrobial active substances of strain HXP-5 were liquid volume 100 mL in 250 mL flask, 210 r/min at 27 °C, inoculation size of 1.7% for 72 h with a medium of 2.3% glucose, 0.25% tryptone+yeast extract (3:1), 0.18% NaCl. [Conclusion] The antagonistic strain HXP-5 to R. solani (Linum usitatissimum L.) was identified as B. subtilis. And it has a stronger effect on biocontrol of Flax Rhizoctonia solani. HXP-5 strain shows stronger antagonistic action to R. solani (Linum usitatissimum L.) under optimized fermentation conditions.

Abstract:[Objective] Plant root-associated fungi (RAF) are essential to the ecological processes involving organic mass decomposition, nutrients cycling of ecosystem, and density-dependent regulation of plant populations. Molecular and culture-dependent diagnosis is commonly used to study RAF community. To evaluate the effectiveness of culture-independent molecular technique on depicting the species composition of Rhododendron RAF communities. [Methods] DNA was extracted from hair roots of R. bureavii and R. leptothrium, and then fungal ITS region was amplified using fungus-specific primers ITS1F and ITS4. ITS-PCR products were cloned, sequenced, and analyzed. Putative trophic mode and guild of RAF were assigned by linking sequences with metadata obtained from a systematic review of published works on RAF ecology from multiple independent studies, and by functional analysis provided by FUNGuild software. [Results] A total of 15 fungal species were identified from hair roots of both Rhododendron species. Of these fungi, 3 species are Basdiomycota and 12 species are Ascomycota. The dominant fungal group Helotiales sp. was detected in RAF community of both Rhododendron species. Fungal taxa on the two Rhododendron plant roots can be assigned to multiple trophic modes and guilds including known ericoid mycorrhizal symbionts Rhizoscyphus sp. and Oidiodendron sp., as well as repeatedly documented endophyte Phialocephala fortinii, symbiotic fungi Pezoloma ericae, and ectomycorrhizal Meliniomyces sp. In addition, saprotrophs Myceana sp., Lachnum virgineum, Herpotrichia sp. were also common in the RAF community of the two Rhododendron. These finding suggests the phylogenetically distant and multiple trophic modes and guilds of fungi co-existing on the Rhododendron roots. [Conclusion] Culture independent molecular diagnosis used here is fast and reliable for fully revealing the Rhododendron plant RAF diversity.

Abstract:[Objective] In order to assess potential of plant growth promoting rhizobacteria (PGPR) for protecting zucchini plants against Fusarium oxysporum, antifungal properties and growth-promoting effects of PGPR were evaluated. [Methods] 19 strains that acquired from preliminary studies were used to antagonize F. oxysporum in vitro based on panel confrontation. Control efficiency of microbial inoculant was measured on zucchini root rot at greenhouse experiments. Growth-promoting effect of compound inoculant instead of some chemical fertilizer was determined at field tests. [Results] There were 9 strains efficiently antagonized F. oxysporum. Among these strains, the inhibition rate of strain FX2 could rise up to 66.80%. In greenhouse experiments, the inhibition rate of microbial inoculant (LHS11+FX2) reached 57.14%. In field experiments, microbial inoculant with different proportional chemical fertilizer had growth-promoting effect on biomass and root morphology, and the yield of 85% chemical fertilizer + compound inoculant significantly increased 27.13%. [Conclusion] The compound inoculant (LHS11+FX2) has excellent control efficiency to zucchini root rot. The growth-promoting effect of 85% chemical fertilizer + compound inoculant is obvious on the growth of zucchini, and it largely saves fertilizer costs and improves production efficiency.

Abstract:[Objective] The aim of this study was to study the degradation of lignin by Comamonas serinivorans C35. [Methods] Comamonas serinivorans C35 growth was measured. Chemical oxygen demand (COD) reduction was investigated. Lignin degradation and decolorization rates were conducted. In addition, secretion of ligninolytic enzymes were investigated by using lignin mineral salt medium. The changes in lignin structural appearance and the chemical bonds of it before and after degradation were assessed by scanning electron microscope (SEM) and fourier transform infrared spectroscopy techniques (FTIR), respectively. [Results] The ability of Comamonas serinivorans C35 in the presence of lignin as a sole carbon source with 44.4% reduction in COD value after 7 days of incubation. The degradation and decolorization removal reached 43.57% and 42.26%, respectively. It was shown that the maximal enzyme activities of lignin peroxidase, manganese peroxidase and laccase of the studied isolate recorded 648.4, 177.8 and 70.1 U/L, respectively throughout the incubation course. SEM revealed the depolymerization of lignin into smaller pieces and FTIR confirmed the benzene ring structure, C–O–C and C=O bonds of lignin were broken down. [Conclusion] The results of this study indicate that Comamonas serinivorans C35 potentiates its ability not only to utilize lignin as a sole carbon source but also its applicable value in lignin bioconversion.

Abstract:[Objective] Study the diversity and community structure of gut actinobacteria of giant panda with the different age and gender, in order to provide scientific basis for searching the actinobacteria possessing potential to produce bioactive compounds. [Methods] Denaturing gradient gel electrophoresis (DGGE) was employed to reveal the gut actinobacteria diversity and community structure of giant panda, and the results were analyzed by multiple comparisons, including UPGMA cluster, PCA and biological diversity of gut actinobacteria in different age and gender. [Results] The diversity and community structure of gut actinobacteria in different panda exhibited significant differences by DGGE analysis. The Shannon-Wiener index (H') and Richness (S) of gut actinobacteria in female giant pandas decreased as they grew older, but the male giant pandas were opposite. The different diversity of gut actinobacteria were observed in different giant panda. However, the diversity index of gut actinobacteria from the same gender possessed higher similarity. The recovery of DGGE strip series showed the 16S rRNA gene sequence similarity between the 28 stronger bands and the typical strains published in GenBank was 96% to 100%, and those sequences belonged to ten genera, Streptomyces was dominant genera accounting for 46% of all sequences, the remainder belonged to genera Kitasatospora, Rhodococcus, Corynebacterium, Dietziaceae, Marmoricola, Beutenbergia, Microbacterium, Streptacidiphilus, Blastococcus, which account for 54%. [Conclusion] This result revealed the intestinal actinobacteria community structure and diversity of giant panda were different and abundant, which were influenced by their age and gender.

Abstract:[Objective] The genetic diversity of lactic acid bacteria which were isolated from raw milk of Yili area in Xinjiang was analyzed. [Methods] The diversity of lactic acid bacteria was analyzed by using pure culture, repetitive genomic fingerprinting (rep-PCR) analysis patterns and 16S rRNA gene sequence analysis. [Results] A total of 29 strains of lactic acid bacteria were obtained from five raw milk samples. The phylogenetic analysis showed that these strains belonged to five phylogenetic groups, they were Lactococcus, Lactobacillus, Leuconostoc, Pediococcus and Enterococcus respectively. The dominant genus was Leuconostoc (27.6%), followed by Lactococcus (24.0%). [Conclusion] The abundant diversity of lactic acid bacteria in the raw milk of Yili area in Xinjiang provided rich resources for exploiting probiotic lactic acid bacteria products.

Abstract:[Objective] The study in order to screen the strain with high yield of autoinducer-2 (AI-2) of lactic acid bacteria strains which isolated from koumiss of Ximeng region in Inner Mongolia, and optimize the condition of recombinant protein to synthesize signal molecule AI-2 in vitro. [Methods] Using biological luminescence method to compare the contents of signal molecule AI-2 which produced by different lactic acid bacteria, with high production of signal molecule AI-2 lactic acid bacteria genomic DNA as a template, expanded its S-adenosine homocysteine nucleoside enzyme (Pfs) gene to build the prokaryotic expression vector. Isopropyl β-D-1-thiogalactopyranoside (IPTG) was used to induce expression of recombinant proteins. The culture medium, induction temperature, the density of bacteria, IPTG concentration and inducing time were optimized to get the high expression of Pfs protein, and finally synthesized signal molecule AI-2 in vitro. [Results] Ten strains of lactic acid bacteria could produce AI-2, and the relative luminescence intensity of AI-2 secreted by Enterococcus faecium 8-3 was obviously higher than other strains. The optimal inducing condition of the recombinant protein was as follows: when the OD600 was 0.5–0.7, using SOC medium as the induction medium, the induction were initiated with 0.1 mmol/L IPTG at 37 °C for 12 h; The optimal inducing condition was used to induce the target protein and obtained the purified Pfs protein with the concentration of 4.08 g/L, and successfully synthesized AI-2 in vitro. [Conclusion] The strains of ten lactic acid bacteria isolated from Koumiss could produce AI-2 and the signal molecule AI-2 of Enterococcus faecium 8-3 could be synthesized by Pfs gene.

Abstract:[Objective] The sequences of pfs gene (encoding the Mtan protein, also known as Pfs) from different serotypes of Riemerella anatipestifer (RA) were analyzed, and catalytic activity of Mtan was studied. [Methods] The different serotypes of RA pfs gene were amplified by PCR and then the homology of nucleotide sequences was analyzed. The recombinant plasmid, pCold-RA-pfs was constructed, and then expressed in BL21 and the recombinant protein RA-Mtan was purified. Furthermore, the activity of RA-Mtan catalyze S-adenosylhomocysteine (SAH) to produce Homocysteine (HCY) was evaluated by Ellman’s assay, and the activity of AI-2 was detected by Vibrio harveyi reporter strain BB170. [Results] The sequence analysis of pfs indicated that the homology of different serotypes varied from 93.9% to 100%. The SDS-PAGE showed that RA-Mtan was soluble expression in BL21. Moreover, the result suggested that RA-Mtan and recombinant protein LuxS (from Avain pathogenic Escherichia coli) could catalyze SAH to produce 176.7 μmol/L HCY. The reaction products were able to induce luminescence of Vibrio harveyi BB170, demonstrating that recombinant RA-Mtan and LuxS synthesize AI-2 in vitro from SAH. [Conclusion] The RA pfs genes from different serotypes were highly conserved. The RA-Mtan can catalyze SAH to produce HCY, and produce AI-2 with biological activity as well. This study will contribute to further study of the roles of pfs in RA.

Abstract:[Objective] The aim of this study was to analyze the taxonomic structure and biodiversity of the endophytic fungi from patchouli and screen the antagonistic endophytic fungi against Ralstonia solanacearum. [Methods] The endophytic fungi were isolated from the roots, stems, and leaves of the healthy patchouli using the tissue isolation method. The taxonomic structure and biodiversity of the endophytic fungi from patchouli were explored based on the morphological traits, and fungal ITS region sequence analysis. And the antagonistic endophytic fungi against Ralstonia solanacearum were screened by double plate antagonistic method. [Results] In the results, 313 strains belonging to 30 genera of endophytic fungi were isolated from patchouli. The dominant groups of the endophytic fungi were Alternaria (28.75%), Phompsis (23.00%) and Colletorichum (11.82%), respectively. In addition, there were some rare fungal endophytes taxa such as Biscogniauxia, Eutypella, Gibellulopsis, Neosartorya, Neofusicoccum, Talaromyces were also isolated. The colonization rates and the isolation rates of endophytic fungi in patchouli stems and leaves were higher than those in roots. However, the diversity index of fungal endophytes in roots (2.64) was higher than those in stems (2.00) and leaves (1.97). The similarity coefficients of fungal endophytes between stems and leave, roots and stems, roots and leaves was 0.35, 0.20, and 0.19, respectively, indicating that the species composition of fungal endophytes in patchouli roots, stems and leaves were not very similar each other. In addition, 16 strains of endophytic fungi showed the antagonistic activities to Ralstonia solanacearum. Among the 16 strains, GHXR07, GHXR27 and GHXR29 showed the best antagonistic activities, and they were identified as Talaromyces sp., Myrothecium roridum Tode and Talaromyces wortmannii (Kl?cker) Benjamin, respectively. [Conclussion] The endophytic fungi in patchouli were very diverse and their distribution showed the tissue specificity, and the antagonistic strains against Ralstonia solanacearum were also demonstrated.

Abstract:[Objective] It is one way of heavy metals into the food chain by algae adsorption. In order to study the fates of Cd2+ in water, the adsorption mechanisms of Cd2+ by living microalgae was studied. [Methods] Four microalgae species, including Spirulina platensis, Microcystis aeruginosa, Scenedesmus quadricauda and Chlamydomonas microsphaera, which are commonly found in surface water, were selected as experiment materials. After simulation experiments, Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of Cd2+ by four organisms. [Results] The results indicated that biosorption isotherm was better fitted by the Langmuir model comparing with the other models in explaining the biosorption of Cd2+ by Spirulina platensis. Freundlich was the best one to describe Chlamydomonas microsphaera, and D-R was the best isotherm when describing the biosorption of Cd2+ by Microcystis aeruginosa and Scenedesmus quadricauda. The adsorption capacity of Scenedesmus quadricauda was the largest, whereas Spirulina platensis was the lowest with the strongest absorbability. It also showed that the biosorption of Cd2+ by the four microalgae was taken place by chemisorption. [Conclusion] There exists large adsorption capacity of living microalgae to Cd2+, which may induce the enrichment of Cd2+ in aquatic animals by eating them. On the other hand, living microalgae can be used as a kind of adsorbent material to remove Cd2+ from wastewater.

Abstract:Autophagy is a complex intracellular biological process, which is regulated by a complex regulatory network involved in a large number of regulatory genes, and plays different roles depending on different tissues and organs, physiological and pathological states. In this review, the research progress in morbillivirus-related autophagy, especially the signal pathway of autophagy induced by the viruses is summarized. Studies on more than 20 families of viruses, and more than 50 different DNA or RNA viruses indicated that autophagy is a double-edged sword to a virus. In morbilliviruses, autophagy is critical for viral replication and spread. It was found that the viral H and F proteins are key molecules involved in morbillivirus-induced autophagy. Recent studies showed that measles virus could induce autophagy via IRGM, which is the key regulatory molecule in RNA virus-induced autophagy signaling pathway. CD46, a receptor of morbilliviruses, also plays a critical role in autophagy. In addition, there may be an important relationship between autophagy and immunosuppression caused by morbilliviruses.

Abstract:29 years have passed since the discovery of bis-(3′,5′) cyclic di-guanylate (c-di-GMP) which is a key bacterial second messenger involved in the regulation of many crucial bacterial processes including biofilm formation and disappearing, cell motility, virulence, cell cycle controlling, cell differentiation and aggregation as well. c-di-GMP plays an irreplaceable role in biosynthesis and transportation of bacterial extracellular polysaccharides (EPS), which are major component of bacterial biofilm. Currently, due to its wide range of application in medicine, food processing, agriculture industries and environmental protection, it has gained more attention from medical and nutritional biochemistry researchers. In this paper we first reviewed recent achievements on crystal structure of c-di-GMP metabolic enzymes and its multiple receptor protein of c-di-GMP with emphasis on its in vivo concentration regulation; then combined with our researches on the regulation of curdlan, biosynthesis by c-di-GMP in Agrobacterium sp. ATCC31749, we further focus on the advancement of c-di-GMP regulation on the biosynthesis and transportation of bacterial extracellular polysaccharides (EPS), such as cellulose, alginate, poly-N-acetylglucosamine (PNAG) and curdlan as well, which were widely used in industrial, pharmaceutical and food applications.

Abstract:In this paper, the properties and functions of Lactobacillus S-layer protein were reviewed. The effects of S-layer protein on surface-properties, adhesion capacities of Lactobacillus bacteria and the regulation of intestinal function are also introduced, including reducing apoptosis caused by pathogenic bacteria, immunoregulating cell activity, participating in the intestinal immune response through the interaction with SIGNR3, exerting biological function through TLRS-MyD88-NF-κB pathway and regulating expression of intestinal mucosa associated proteins. Thus demonstrated that S-layer protein plays an important role in the function of immunoregulatory effect.

Abstract:Phytoremediation, as promising remediation technology of heavy metal contaminated soils, could be more effective when assisted by microbes. Plant growth-promoting rhizobacteria (PGPR) can promote plant growth and improve plant tolerance to heavy metals through different mechanisms, such as indole-3-acetic acid (IAA) secretion, siderophore production, nitrogen fixation or phosphorus dissolution. Arbuscular mycorrhizal fungus (AMF), as important functional microorganisms in the soil-plant system, can regulate root morphology and mineral nutrition condition by infection of plant roots, adsorb heavy metals by mycelium, and change heavy metals bioavailability by production of secondary metabolites, such as glomalin, organic acid and auxin. PGPR and AMF can have beneficial synergetic effect on plant growth and heavy metal sequestration, which offers a potential for the phytoremediation of heavy metal contaminated soils. To date, many studies have been conducted worldwide about the interaction between AMF and PGPR, but the mechanisms involved are still poorly understood. In this paper, the mechanisms driven by PGPR and AMF, representing a potential for the phytoremediation of heavy metal contaminated soils, were extensively reviewed and recommendations for future investigations were made.

Abstract:Chinese Strong-flavor Baijiu (CSFB) is a traditional Chinese fermented beverage with sales accounting for more than 70% of total Baijiu consumption in China. CSFB is produced by fermentation of grains in cellars lined with pit mud (PM). This PM, fermented clay, contains large amounts of functional microbes, which are of great importance in determining the production of aromatic compounds in CSFB. Because of this key role, many researches have been conducted in recent years to study the effect of PM microbial mechanisms on the CSFB production. In the present paper, we introduced the recent advances in research on the diversity and succession of PM microbial community, the relationship between microbial community structure and PM quality, and the breeding and application of PM functional microbes. Then, the main associated issues were analyzed and the research prospects were put forward. Firstly, the comparative study on PM microbial community structure should be developed to illustrate the relation between microbial community structure and CSFB quality, and improve the PM quality appraisal system. Secondly, the isolation and improvement of functional strains should be enhanced, and the metabolic pathways and its influence mechanism of isolates should be demonstrated to promote the potential application of PM microbes. Finally, the detail affecting function of microbial agents used in the manufacture of artificial PM should be investigated. When the mechanisms of complex microbial agents were demonstrated in the aspects of microbial community structure and metabolism, quality control on the microbial agents could be promoted.

Abstract:Micro-lecture is a kind of visible learning resource which is generated for online learners and designed with learner centered. The application of micro-lecture often combined tightly with flipped classroom. In order to solve problems associated with the teaching and learning of the course Food Microbiology Experiment, an experimental teaching mode of flipped classroom based on micro-lecture video was developed, which included five aspects of “video, platform, watching, imitation and evaluation”. The teaching mode has shifted the course from “teaching predominant” to “learning predominant”, as well as from “knowledge transfer predominant” to “ability training predominant”. As a result, the strategy improved students’ autonomous learning ability and learning interest, hence it obviously improved the teaching effectiveness.

Abstract:Assessment is an important component in teaching management, and plays a vital role in learning orientation. In the teaching of Microbiology and Microbiology Experiments, a close attention should be paid to such a guiding role. At the beginning of the course, the composition and proportion of the grade points should be outlined. Beside routine participation in class, students should also be able to expand their knowledge body by doing literature research from internet and library. For this purpose, a series of lab reports and a course presentation were required. The lab examination accounted for 10% of the total score, and the tested skills included inoculating, smearing, staining and oil microscopic technique; The final written examination accounted for 50% of the total score, and the tested capacities included the abilities to master the basic concepts, the abilities to synthesize multiple knowledge sources, and the abilities to analyze and solve problems. The evaluation guide sets a goal for students to systematically master microbiology knowledge, and to comprehensively improve their experimental skills and innovation abilities as well.

Abstract:Flipped classroom is gradually adopted in college education recently because it takes students as the main body of teaching activities and teachers as study guiders. This paper introduces the exploration and practice of flipped classroom in the teaching activities of the course immunology, including the design and arrangement of the course, extraction of the knowledge points, provision of self-study material, design and implementation of effective class activities, evaluation approach and summarization of teaching experience. The flipped classroom model turned imparting knowledge one-way to two-way interaction, and turned passive learning to active learning. For students, not only the basic knowledge of immunology was grasped, but also the independent study ability was improved.