Abstract:[Background] Poor thermostability of Rhizopus chinensis lipase limits its potential in industrial applications. [Objective] Rationale molecular design was used to improve the thermostability of r27RCL (from Rhizopus chinensis lipase CCTCC M201021). [Methods] Seven eligible cysteine pair mutations were selected according to the prediction of the Disulfide by design algorithm. Mutant gene was produced by whole-plasmid PCR and then expressed in Pichia pastoris to obtain mutant lipases. [Results] The optimal mutant enzyme m9/10 (S85C-Q145C) showed improved thermostability with a 4.5-fold increase in t1/2 at 60 °C and a 4.2 °C increase of Tm compared with the parent enzyme, without compromising the catalytic efficiency. A disulfide bond between 85 cysteine residue (located in 2nd β-sheet) and 145 cysteine residue (located in 4th α-helix) was introduced into the lipase according to the cystal structure, leading to the improved thermostability of lipase. [Conclusion] The thermostability of fungal lipase could be greatly improved by newly introduced disulfide bond.

Abstract:[Background] Acetogens are a group of anaerobic bacteria that use Wood-Ljungdahl pathway for the assimilation of CO2 into cell carbon and production of acetate or ethanol. They are widely distributed in nature and highly phylogenetically and metabolically diverse. The investigation on the metabolic capabilities of acetogenic bacteria is important to understand their physiological and biochemical characteristics as well as environment roles. [Objective] This study aims to optimize the culture conditions and understand the autotrophic and heterotrophic characteristics of a strain of novel acetogenic bacterium Clostridium sp. [Methods] The incubation was performed at temperature of 10?55 °C, initial pH of 6.0?9.0, NaCl concentration of 0?2.0% or with different nitrogen source to optimize the culture condition of stain BXX by determining the cell and product concentration. The autotrophic or heterotrophic growth characteristics of strain BXX were studied by measuring substrate consumption, product generation, bacterial concentration and pH with CO, syngas, H2/CO2, glucose and other organic matters as substrates. [Results] The optimum temperature, initial pH, NaCl concentration and nitrogen source of strain BXX was 30 °C, 7.0, 1.0% and yeast extract, respectively. Strain BXX grew on H2/CO2, syngas, glucose, 1,2-propanediol, sodium formate, 2-methoxyethanol and glycerol, and did not grow on CO, pyruvate or lactate. [Conclusion] Strain BXX grew autotrophically to produce acetate and grew heterotrophically to produce ethanol. Strain BXX was an excellent strain resource for acetate fermentation and had good potential of industrial application.

Abstract:[Background] Mangrove habitats are rich in microbial resources. Isolation of more pure culture actinomycetes can provide strain resources for the discovery of new antibiotics. [Objective] A new actinomycete isolation medium was used to explore the strain resources of actinomycetes in mangrove habitats of Maowei Sea in Guangxi Beibu Gulf. Separation effect of new actinomycetes isolated culture medium was evaluated. [Methods] Coconut juice-mycose medium was newly designed and used for isolating actinobacteria from mangrove rhizosphere soil and mangrove root bark in Guangxi Beibu Gulf, Maowei Sea. The diversity analysis of pure culture actinomycetes was carried out based on molecular biology method. [Results] 65 strains of actinomycetes, including 4 potential new taxa, were isolated from the rhizosphere soil of mangrove which distributed in 5 orders, 10 families and 15 genera. Seven, five and eleven genera were isolated by YIM171, MA and coconut juice-mycose medium respectively. 19 strains of actinomycetes, including 4 potential new taxa, isolated from the root bark of mangrove were distributed in 4 orders, 7 families and 10 genera, 7 genera were isolated by YIM171 medium and coconut juice-mycose medium, respectively. Three potential new taxa were obtained from two kinds of samples in mangrove habitats using Coconut juice-mycose medium. [Conclusion] Rhizosphere soil and root bark of mangrove in Guangxi Beibu Gulf, Maowei Sea present an extremely abundant habitats for the isolation of a significant diversity of actinomycetes. Coconut juice-mycose medium is effective in the isolation of actinomycetes thus can be considered as the isolation medium for actinomycetes.

Abstract:[Background] Although poly(butyleneadipate-co-terephthalate)/PBAT plastic mulch is biodegradable, little is studied on its microbial degradation. [Objective] This study was to screen bacteria from different environmental samples for degrading PBAT plastic mulch. Through the analysis of community succession structure at multiple enrichment, the core microbe group of degrading PBAT plastic mulch bacteria was studied. [Methods] The modified SM inorganic salt medium was used to screen microorganisms that can degrade PBAT plastic mulch from different environmental samples. The efficiency of microbial degradation community was determined by weight-loss method. By using 16S rRNA gene high-throughput sequencing technology, the community structure from the fifth (G5) to ninth (G9) enrichment was studied. The relative abundance of different bacterial community and the PBAT plastic mulch degradation time were analyzed by Pearson correlation analysis. [Results] The biodegradable bacterial community capable of completely degrading PBAT plastic mulch was selected from the compost samples of Guangzhou Composting Plant and named SX. Through continuous transfer and enrichment, the degradation time of PBAT plastic mulch by bacteria SX decreased from 28 days (fifth, G5) to 13 days (9th, G9), indicating that the degradation rate of PBAT plastic mulch significantly increased. The high-throughput sequencing of the 16S rRNA gene showed that the relative abundance of Firmicutes gradually decreased in the fifth (G5) to ninth (G9) of PBAT plastic mulch degrading community, and the relative abundance of Actinobacteria gradually increased. The relative abundances of Arthrobacter sulfureus, Rhodospirillaceae, and Chitinophagaceae were gradually increased, however the relative abundance of Bacillus sp. was significantly decreased. Statistical analysis revealed that the relative abundance of Arthrobacter sulfureus was significantly associated with the reduction of PBAT plastic mulch degradation time (r=–0.927, p<0.05). [Conclusion] This study provided a green, highly efficient and environmental friendly new pathway and strain resource for the degradation of PBAT plastic mulch.

Abstract:[Background] Forest soil bacterial diversity is one of important indexes to measure forest quality. The composition and change of soil bacterial community structure can reflect the structure and function of forest ecosystem. They play important roles in the circulation of nutrients in forest ecosystems. [Objective] The influence of different forestry density on soil bacterial community structure was analyzed and discussed in Liuxihe National Park, in order to provide a reference for the restoration of degraded ecosystems, rational utilization of forestry resources, conservation of soil fertility, improvement of ecosystem productivity and service functions of forests. [Methods] A manipulative field experiment was conducted to investigate the effects of three different forest types: high density forest type (HD), medium density forest type (MD), low density forest type (LD). The soil samples were collected by “S” sampling method and the total DNA of soil microbes was extracted. 16S rRNA gene sequences were sequenced by Illumina Miseq sequencing and analyzed using R language, SPSS 21.0 and other software. [Results] The soil fertility of high density forest was higher than those of medium and low-density forests. Soil bacterial diversity index and richness index differed among different density forests, and the highest was in middle-density forest. Proteobacteria and Acidobacteria are the major groups in Liuxihe National Park. [Conclusion] The soil bacterial diversity is abundant in Liuxihe National Park. Proteobacteria and Acidobacteria are the major groups. Soil bacterial diversity, richness and community structure were significantly affected by forest density. The medium density forest type (1 800?2 200 plants/ha) in Liuxihe National Park is suitable for bacterial growth. The fertility of soil was affected by the forest density and shrub weeds. Intragenomic heterogeneity of 16S rRNA genes causes overestimation of bacterial diversity.

Abstract:[Background] Resuscitation promoting factor (RPF) is an active protein secreted by some different actinobacteria species, which was first reported in Micrococcus luteus. It resuscitates the dormant bacteria and promotes the growth of active bacteria. However, few studies have investigated its contribution in environmental samples to the growth or resuscitation of bacteria other than the original host. [Objective] In order to find novel strains and explore the functional bacteria, we investigated the role of RPF in promoting the latent dormant bacteria from specific environmental sample. [Methods] Firstly, bioinformatics analysis and homology modeling of Micrococcus luteus RPF (MlRPF) was performed. Subsequently, the MlRPF encoding gene was cloned and expressed in Escherichia coli; Finally, we used the purified recombinant MlRPF to study the resuscitation effect toward latent dormant bacteria from an activated sludge sample. [Results] Bioinformatics analysis revealed that the MlRPF branched separately and was distant from other RPF family members in the phylogenetic tree. Structural analysis of its “RPF-domain” suggested that MlRPF has a similar catalytic structure domain as C-type lysozyme, this finding helps explain why RPF family members have lysozyme-like activity; the recombinant MlRPF was expressed in soluble form in E. coli expression system, could promote the growth of M. luteus IAM 14879 and retain its physiological activity. By used purified recombinant MlRPF, we isolated Dietzia, Paracoccus, Rhodococcus, and Brevundimonas strains from an activated sludge sample. [Conclusion] These results not only provide a novel method for the study of microbial diversity and the exploration of special microbial resources in environmental samples, but also provide a theoretical basis for the research and development of wastewater bioaugmentation technology based on MlRPF.

Abstract:[Background] Benthic animals are an indispensable constituent of lake eco-environment and play an important role in transformation of nitrogen between sediment and water. There have been showed that benthic animals are the potential source of N2O emission, while the release capability is closely related to habitat environment. The water quality without cyanobacterial accumulation is different from that with cyanobacterial accumulation, which is usually a hot spot of N2O emission. [Objective] To compare the N2O emission of the fresh invertebrates between with and without cyanobacterial accumulation. [Methods] Combing gas chromatography with modern molecular biology techniques, the N2O emission flux and intestinal microbial from Corbicula fluminea were analyzed to extend our knowledge about the microbiology mechanism of N2O emission through laboratory microcosm experiment. [Results] with cyanobacterial accumulation the N2O emission flux of C. fluminea was 447.2 pmol/(ind·h), decreased by about 63% in comparison with control group. The intestinal bacterial and denitrifying bacteria of C. fluminea have different responses to cyanobacterial accumulation. The 454 pyrosequencing revealed that Proteobacteria (β- and δ-), Chloroflexi and Bacteroid were dominant bacteria in control group and occupied about 67.3% of the total bacteria number. While in cyanobacterial accumulation treatment the intestinal microorganism was mainly Proteobacteria (α- and β-), and the relative abundance reached 85.8%. The index of Chao1 and Shannon indicated that the richness and diversity of intestinal bacterial community structure in cyanobacterial accumulation treatment were lower than the intestinal bacterial in control group. Further analysis was conducted on denitrifying bacteria in the intestine of C. fluminea, the result showed that the relative abundance of denitrifying bacteria in cyanobacterial accumulation treatment occupied to 22.6%, which was 2.3 times as much as the control group, thus strengthening the intestinal denitrification. [Conclusion] cyanobacterial accumulation decreased the richness and diversity of the intestine bacteria from C. fluminea, while increased the abundance of intestinal denitrifying bacteria, probably enhanced the complete denitrification, resulting in decreasing the emissions of N2O from C. fluminea. The data obtained in this study could serve as a valuable resource for the environmental effects of benthic animals, which has a great theoretical and practical significance in greenhouse-gas control.

Abstract:[Background] Gold nanoparticles (AuNPs) have various applications in optics, electronics, biomedicines and catalysis due to their high stability, oxidation resistance and biocompatibility. The current research on microbial synthesis of gold nanoparticles is less. [Objective] We performed the intracellular biosynthesis of AuNPs with the biomass of Trichoderma viride. The effects of the biomass addition, initial gold ions concentration and solution pH were also evaluated. [Methods] We performed the intracellular biosynthesis of AuNPs using biomass of Trichoderma viride (GIM3.141). By visual method, ultraviolet visible (UV-vis) spectrophotometer and X-ray diffraction (XRD) and transmission electron microscopy (TEM) and other means to analyze the characteristics of the synthesis of AuNPs. The possibility of biosynthesis of AuNPs was discussed. The effect of reaction conditions on the characterizations of the AuNPs was also evaluated. [Results] The particle size decreased with the increase of biomass addition and solution pH, and increased with the increase of initial gold ions concentration. Reaction conditions such as biomass addition, solution pH and initial gold ions concentrations exhibited great effect on the AuNPs location and size distribution. [Conclusion] On exposing the biomass of Trichoderma viride to aqueous solution of HAuCl4, AuNPs with various shapes including pseudo-spherical, triangular, quadrilateral, and hexagonal ranging from several nanometers to more than 300 nm were produced. For large scale, low cost, clean biosynthesis nanoparticles process provides the species resources.

Abstract:[Background] With cost reductions for DNA next generation sequencing, researchers have readily utilized these tools to identify taxonomic diversity of arbuscular mycorrhizal fungi (AMF). Globally, the molecular diversity and distribution of AMF in the world has attracted attention, whilst there has been little research on the molecular diversity of AMF at the regional scale in China. [Objective] We characterized the molecular diversity and distribution of AMF in China at different ecosystems (grassland, human-made, forest), climatic regions (temperate, subtropical, polar), and localized sampling strategy (DNA from roots or soil). [Methods] Based on Davison’s AMF global database (2015), and supplemented some data published after 2015, a new AMF database was established on the molecular diversity at the regional scale in China. [Results] A total of 145 virtual taxa (VT) identified, belonging to 8 families and 12 genera. For ecosystems, the molecular richness of AMF in the grassland ecosystem was the highest, accounting for 60.7% of the total VT, with the human-made ecosystem and forest ecosystem also reached 55.2% and 43.4%, respectively. Similarly, the species richness of VTs in AMF also varies with the climatic region, with the highest percentage in the temperate climate (64.1%), followed by the subtropical climate (60.7%), and least in the polar climate (20.7%). VT richness of AMF was also influenced by sampling fractions from roots and soil, with richness of AMF found in root samples (80.0%) was higher than that of AMF in soil (48.3%). [Conclusion] China has high AMF molecular diversity as quantified by species richness, at different climatic regions, ecosystems, and sampling strategy at the regional and localized scale.

Abstract:[Background] Streptococcus pneumoniae is one of the most common pathogens of community-acquired pneumonia, and causes a variety of other serious diseases including bacterial meningitis, sinusitis, otitis media and bacteremia, and poses health threats to humans, especially among children and the elderly, or individuals with immature/compromised immune systems. Iron is essential for Streptococcal survival and infection, and haem ABC uptake system PiuABCD is the most iron ABC uptake system for S. pneumoniae. [Objective] Clone, express and purify hemin-binding lipoprotein PiuA belonging to haem ABC uptake system PiuABCD, and characterize its hemin-binding properties in vitro. [Methods] The piuA (spd_1652) gene from S. pneumoniae D39 strain was ligated into pBAD-HisA vector, and expressed in E. coli Top 10 strain, then the PiuA-His fusion protein was purified using Ni-NTA affinity chromatography, and the His tag free PiuA protein was obtained by cutting off the His tag with enterokinase. Finally, the hemin-binding properties of PiuA protein were characterized by circular dichroism, UV spectroscopy and fluorescence spectroscopy. [Results] We successfully constructed recombinant vector pBAD/HisA-piuA, and acquired the PiuA protein with the purity higher than 95%. CD spectra showed that hemin binding did not induce any significant structural change in PiuA, UV spectroscopy revealed that PiuA protein can specifically bind hemin, and fluorescence spectroscopy demonstrated that the binding constant K between the PiuA and hemin is 3.4×105 L/mol. [Conclusion] Hemin-binding lipoprotein PiuA can specifically bind to hemin and provide the iron for Streptococcal survival and infection, these characterization results of PiuA protein provide basis data for design of antibacterial drug targeted for haem ABC uptake system PiuABCD.

Abstract:[Background] Cotton Verticillium wilt, caused by Verticillium dahliae Kleb., is one of the most devastating diseases. Biological control has been drawn more and more attention in recent years for its safety to environment, human and animal. [Objective] In order to expand strain resources for biological control of cotton Verticillium wilt, we urge to isolate, screen and identify highly efficient antagonistic bacteria against Verticillium dahliae Kleb. [Methods] The bacteria were isolated by spread plate method, the antagonistic bacteria were obtained by primary screening and subsequent screening. Strains were identified based on morphological, physiological and biochemical characteristics and 16S rRNA gene sequence analysis. [Results] 535 strains of antagonistic bacteria were primarily isolated and 108 strains of them were further tested. Finally, four highly efficient antagonistic bacteria were screened. Based on morphological, physiological and biochemical characteristics and 16S rRNA gene sequence analysis, strains BHZ-29, SHT-15, SHZ-24 and SMT-24 were preliminarily identified as Bacillus velezensis, Bacillus subtilis subsp. spizizenii, Bacillus atrophaeus and Bacillus vanillea, respectively. [Conclusion] Four highly efficient antagonistic bacteria were obtained and the inhibition effect of Bacillus vanillea on cotton Verticillium wilt was reported for the first time.

Abstract:[Background] Xinjiang Yumin county is the largest safflower planting base of China, its unique geographical environment and climatic conditions suitable for the growth and it is beneficial to formation of quality of safflower. [Objective] The purpose of this study was to explore the relationship between the bacterial community of safflower rhizosphere soil and its environment factors in different growth periods in Xinjiang Yumin hilly area, which may help to provide scientific basis for revealing the nature and low of geoherbalism to genuine regional drugs. [Methods] Took the rhizosphere soil and bulk soil of the vegetative growth stage and reproductive growth stage in the 3 sample plots of Yumin cultivated safflower respectively, determined the soil properties and extracted the genomic DNA, and then established libraries through PCR amplification of 16S rRNA V4 region. Abundance, diversity and structure of soil bacteria were analyzed by bioinformatics technology after sequenced by Illumina HiSeq high-throughput sequencing platform. [Results] A total of 10 303 operational taxonomic units (OTUs) were obtained from 36 soil samples of safflower, and it have identified belonging to 405 species, 738 genera, 381 families, 201 orders, 102 classes, 47 phyla, in which the Actinobacteria (32.9%) and Proteobacteria (28.7%) were predominant. ANOVA analysis showed that there was no significant difference between the richness index Chao1 and the diversity index Shannon in the bacterial communities of the four group samples. However, the principal coordinate analysis (PCoA) and the distribution of species abundances at the level of bacterial genus revealed that there were significant differences in the composition of bacteria communities between different sample plots. [Conclusion] There are a lot to adapt to the changing environment of bacteria in rhizosphere soil of safflower, the presence of these bacteria may have positive effects on forming geoherbalism of the safflower. In addition, soil properties, plant growth stage and root exudates are the possible factors who committed to form the geoherbalism of safflower by effects the rhizosphere bacterial community.

Abstract:[Background] Brochothrix thermosphacta is the main spoilage bacterium in Crucian Carp (Carassius auratus) during storage at 4 °C. Plantaricin 163, a new broad-spectrum bacteriocin produced by Lactobacillus plantarum, significantly extends the shelf life of crucian carp. [Objective] To investigate the antibacterial activity and mechanism of action of Plantaricin 163 against B. thermosphacta. [Methods] The minimum inhibitory concentration and bactericidal kinetics of Plantaricin 163 were determined to measure the antimicrobial effect of Plantaricin 163 on B. thermosphacta. Change in conductivity, and nucleic acid and protein leakage were measured, and flow cytometry, scanning electron microscopy, and transmission electron microscopy were performed, to determine the mechanism of action of Plantaricin 163 against B. thermosphacta. [Results] The MIC of Plantaricin 163 against B. thermosphacta was found to be 32 μg/mL, which was better than that of nisin, and the mode of action of the bacteriocin was killing of cells instead of growth inhibition. The permeability of the cell membrane was increased and caused a change in extracellular conductivity, thereby destroying the integrity of the cell membrane and resulting in the leakage of cell contents. The external morphology and internal structure of the cells were affected, eventually leading to cell death. [Conclusion] Plantaricin 163 can destroy the membrane and internal structure of B. thermosphacta.

Abstract:[Background] Weissella exists widely in fermented foods. Strains of this genera are involved in fermentation and contribute to the formation of volatile compounds. In soy sauce moromi mash, Weissella is the dominant genera of bacteria. Thus, it is of great importance to characterize their adaption to the environment, as well as properties related to soy sauce fermentation. [Objective] To isolate the main species of Weissella from soy sauce moromi mash, and evaluate their function for soy sauce fermentation by analyzing the dynamic composition of each species and their adaptation to the environment. [Methods] Characteristics of Weissella and their effect on the safety of soy sauce and fermentation process were evaluated by detection of quantity of Weissella during soy sauce fermentation, and their capability in production of short chain fatty acids, extracellular polysaccharides, biogenic amines (BA) and ethyl carbamate or their precursors. [Results] A total of 16 strains of Weissella, including Weissella confusa, Weissella paramesenteroides and Weissella cibaria, were isolated from soy sauce moromi mash. W. paramesenteroides was found to be tolerant to salt stress that confers the main species of Weissella in the moromi mash. The capability of short chain fatty acids synthesis of W. paramesenteroides is higher than that of W. confusa and W. cibaria. Production of toxic ammonia compounds are diverse for Weissella strains. Some strains of W. paramesenteroides produce more than one BAs and accumulate citrulline, the precursor of ethyl carbamate, while W. cibaria degrades a variety of BAs. [Conclusion] The tolerance of Weissella isolated from soy sauce moromi mash to salt stress, their growth at temperature lower than the optimal one, and their metabolisms were disclosed. This is important to elucidate the function and characteristics of Weissella for soy sauce fermentation and safety control in processing

Abstract:[Background] follicle-stimulating hormone receptor (FSHR) is secreted by the anterior pituitary cells which expressed in the cell surface of human mature osteoclasts and mononuclear, was regarded as potential targets for blocking FSH. [Objective] For the purpose of obtaining soluble FSHR protein in order to acquire FSHR nanobody with high affinity for the treatment of related diseases caused by FSH and bone loss. [Methods] Recombinant plasmid pET30a-FSHR234 was double enzyme cut by XhoⅠand BamHⅠ, fshr gene was constructed to the pGEX-4T-1 vector and expressed in the prokaryotic cell. Its’ binding capacity was determined by Western blot and ELISA. Immunized Xinjiang camels were used to prepare polyclonal antibody. Phage display technology was used to obtain FSHR nanobodies of high affinity. The expression of coav-3 was detected by cellular immunochemistry. [Results] In this study, recombinant pGEX-4T-1-FSHR was constructed successfully, and the soluble FSHR234 protein expressed with high concentration. Five FSHR nanobodies were obtained successfully by mean of subclone. [Conclusion] The titer of camel FSHR polyclonal antibody prepared in the experiment was 1:128 000. VHH-3F9 nanobody could combine FSHR234 at a low concentration and its binding capacity enhanced with increasing FSHR234 concentration. In addition, both FSHR polyclonal antibody and VHH-3F9 nanobody could expressed on the surface of coav-3.

Abstract:[Background] Marine-derived natural products have become an important source of small molecule drugs in recent years. Genomic analysis showed that Streptomyces sp. B9173 contains a variety of biosynthetic gene clusters of natural products, with the potential to generate multiple new compounds. [Objective] The objective of this paper is to find new compounds with novel structures or unique biological activities from the strain B9173. [Methods] With the method combined with HPLC and LC-MS, we excluded the known compounds produced by B9173 and identified three unknown compounds as isolation targets. The secondary metabolites were isolated and purified using normal or reverse phase column chromatography, gel column chromatography and high performance liquid chromatography (HPLC). The structures of the compounds were elucidated by using mass spectroscopy (MS) and nuclear magnetic resonance (NMR). [Results] Three compounds were purified and identified as tryptanthrin, meisoindigo, and N,N-dimethylisoindigo. All three compounds belong to the 2-oxindole alkaloids. Tryptanthrin has diverse biological activity, including antibacterial activity, anti-inflammatory activity, anti-tumor activity. Tryptanthrin is a potential drug lead and it is the first time to be isolated from bacteria. Meisoindigo is a drug used for clinical treatment of chronic myelogenous leukemia in China. It was isolated for the first time in a microbial fermentation broth. Based on the metabolic background of B9173, we speculated the biosynthetic pathways of three compounds. [Conclusion] Three 2-oxindole alkaloids were purified and structurally elucidated based on their UV-vis spectra and MS data. This study enriches the types of microbially active natural products. The proposed biosynthetic pathways will lay the foundation for further research on the biosynthetic mechanisms of tryptanthrin and meisoindigo. Subsequently biosynthetic pathways for this class of compounds can be reconstructed using synthetic biology techniques, which will provide more convenient and low-cost biosynthesis method for tryptanthrin and meisoindigo.

Abstract:[Background] Sweet cherries are highly perishable fruits because of their tender and juicy flesh. Shihezi is one of the newly plantation area of sweet cherry in Xinjiang, however, the economic losses caused by postharvest rot are huge. [Objective] In order to improve the postharvest quality and prolong shelf life of sweet cherry, this study aims to isolate and identify the pathogens from sweet cherry harvested in Shihezi. [Methods] Fungal strains were isolated from decayed sweet cherry harvested from 136 regiment, Shihezi, and these strains were inoculated back to healthy sweet cherry to test the pathogenicity according to the Koch’s postulates. Pathogens were identified using morphological characteristics and internal transcribed spacer (ITS) sequences analysis. [Results] Five types of filamentous fungi were isolated from the rotten tissue of sweet cherry, in which three types were pathogens of sweet cherry fruit harvested in Shihezi. The representative strains were identified by internal transcribed spacer sequences as Mucor fragilis, Fusarium sp. and Penicillium camemberti, respectively. [Conclusion] M. fragilis, Fusarium sp. and P. camemberti were pathogens causing postharvest rot on sweet cherry harvested in Shihezi, Xinjiang.

Abstract:[Background] Rap1 is a kind of small GTPase, and the method of its activity detection is very scanty. At present, the method mainly depends on commercialized kit, resulting in the high cost. RalGDS has the Rap binding domain (RapBD), which can bind to GTP-Rap1 specifically. [Objective] Establish an inexpensive method of detecting human Rap1 activity by exogenous GST-RapBD fusion protein expressed in Escherichia coli. [Methods] We constructed the plasmid with pGEX-4T-1 vector expressing GST-RapBD fusion protein in E. coli, and then combined GST-RapBD with GST affinity resin. Finally, we used GST Pulldown assay to detect Rap1 activity. [Results] The method of detecting human Rap1 activity was established successfully. [Conclusion] Sequence optimization made pGEX-4T-1 highly express the GST tagged RapBD protein in E. coli, which increased the efficiency and decreased the cost of Pulldown assay to detect GTP-Rap1.

Abstract:As a practical and efficient strain breeding technology, genome shuffling has circumvented the essential requirements of comprehensively cognized genetic background and operable genetic system for the microbial manipulations, and could break through the species limit to accelerate the directed evolution of important microorganisms via the recursive protoplasts fusion. Hence it has been widely applied for the strain improvement and the industrial development of various metabolites in the microorganisms. In the post genomic era, the rapid development of omics and bioinformatics make genome shuffling as an important bridge to link different strain breeding methods, and enable us to explore the complex metabolic networks and global regulatory mechanisms in microbes, which provides an opportunity to design the accurate manipulation for the directed evolution of target microorganism. This paper has systematically summarized the recent applications of genome shuffling in the microbial strain improvement, the research progresses involving related studies in genomics, transcriptomics and proteinomics are especially described in detail. Moreover, the great potential of combinative applications of genome shuffling with omics, bioinformatics, and synthetic biology, are also forecasted.

Abstract:Mycorrhizae are symbiotic structures formed in the roots of plants after mycorrhizal fungi infect plant roots. The use of mycorrhizae as a bio-enhancing technology in the phytoremediation of heavy metal-contaminated soil has attracted extensive attention of researchers. A large number of studies have shown that mycorrhizae can strengthen the heavy metal transportation and accumulation, and root stabilization processes of plants. In addition, they can promote the absorption and utilization of nutrients, stabilize intracellular redox balance, regulate the expression of resistance-related genes, and alter the micro-environment in the rhizosphere to improve host plant resistance to contaminants. In this paper, through reviewing the results and mechanisms of using plant-mycorrhizal fungal combinations to rehabilitate soil polluted with heavy metals, the bottleneck problems that limit the application of this technology and the future research directions are analyzed. This may provide a theoretical basis for the application of combined plant-mycorrhizae bioremediation technologies.

Abstract:By exploring the two core topics about “How to teach?” and “How to learn?”, we practiced the teaching reform based on the course Veterinary Molecular Virology. By renewing teaching concepts and improving teaching methods, and making use of “joint teaching” for “Professional type” and “Academic type” master degree training, we promoted the “covered” and “balanced” teaching to ignite students’ interests, strengthen learning process, improved learning efficiency, and inspired creative thinking. Navigated by the scientific questions designed during the teaching procedure, the students’ learning ability, thinking habit, and creativity could be strengthened through guiding the students’ active inquiry, deeply analyzing, and expanding the extended consciousness and behavior. Through the assessment of students’ knowledge, competence, and quality, highlights the concept of “trinity” of talent cultivation centering on knowledge inquiry, ability construction, as well as personality cultivation, and realizing the all-round promotion of innovative thinking and comprehensive ability, commit to the training of professional veterinary elites.

Abstract:Food microbiology is a compulsory basic course for food science and engineering, food quality and safety in universities. The course experiment skill is must master the basic skills of students majoring in food, and the traditional experiment teaching exists and disconnect, students’ employment demand low participation of many problems, to cultivate students’ ability of working independently. In order to cultivate students’ comprehensive practical ability and adapt to the demand of employment, to guarantee the practical teaching quality of the course, on the basis of more than 30 research microbial post actual employment unit, integrating the original experiment teaching content into two comprehensive experimental projects, covers all the basic food microbiology experiment skills. Practice shows that the two comprehensive experiments of project can effectively improve the effect of food microbiology experiment teaching, make students get the basic experimental skills of food microbiology, help to improve students’ comprehensive ability, realize the seamless joint between students and employment.

Abstract:[Background] Salmonella is an important food-borne pathogen causing disease such as gastroenteritis, typhoid fever and paratyphoid fever in humans and animals worldwide. The pathogenic mechanism is still unclear. Gene knockout plays an important role in studying the pathogenicity of Salmonella, however, currently it is time consuming and the success rate is very low. S. typhimurium has a Type VI secretion system (T6SS). The component Hemolysin-coregulated protein (Hcp) may play an important role in its pathogenicity. [Objective] To establish a quick and effective gene knock out system by knocking out the three Hcp encoding genes in S. typhimurium, thus to study the pathogenicity of Salmonella. [Methods] Kanamycin resistance gene fragments with homologous upstream and downstream sequences of hcp genes were amplified with pKD4 as template, and then were introduced into S. typhimurium which has Red recombination system enzyme. Then pCP20 were electroporated into the cells to delete the integrated kanamycin resistant gene from the recombinant bacteria. [Results] Both individual hcp genes and their recombinations were successfully knocked out from the genome of S. typhimurium. We also summarized some solutions to the problems we may encounter. [Conclusion] Red recombination system is a good method to knock out genes in S. typhimurium. We can improve the efficiency by optimizing the experimental conditions such as the length of the homologous fragment, the concentration of the PCR templates, the time point for L-arabinose addition and the culture temperature. It is a simple and efficient method and deserves to be popularized.