Abstract:[Background] Polycyclic aromatic hydrocarbons (PAHs) are highly toxic organic contaminants which are widely spread in the marine environment, especially in the coastal environment. As an important component of the coastal environment, seagrass ecosystems are under serious degradation status because of the effect of artificial activities including environmental pollutions. Microbial bioremediation has many advantages, such as cost-effective and environmentally friendly without secondary pollutions, and becomes the important way to restore PAHs-contaminated environments. [Objective] This study aimed to explore the feasibility of microbial remediation of PAHs-contaminants in seagrass ecosystems. Seagrass sediment from Daya Bay in Shenzhen City has been collected to isolate the effective PAHs-degrading bacterium, and the degrading characteristics of the strain have been analyzed. [Methods] The PAHs-degrading bacterium was isolated by phenanthrene as the sole carbon source, and the morphological observations, physiological and biochemical experiments and 16S rRNA gene sequences molecular analysis had been conducted for its identification. In the meanwhile, nidA gene, a functional gene for PAHs degradation, was amplified from the strain by specific primer. Finally, we used incubation experiments to analyze the strain’s degradation characteristics. [Results] A highly effective phenanthrene-degrading strain SCSIO 43702 was isolated and identified as a potentially novel species of the genus Roseovarius, and nidA gene was successfully amplified from Roseovarius SCSIO 43702. The result of incubation experiments showed that Roseovarius SCSIO 43702 could degrade 96% phenanthrene (100 mg/L) within ten days, and its optimal degrading conditions were as follows: the temperature at 30 °C, pH value at 7.5 or 8.0, salinity at 3%. [Conclusion] The bacterium Roseovarius SCSIO 43702 has high phenanthrene-degrading ability and environmental adaptability, these characteristics indicate the bacterium has great potential to be developed as microbial agents for PAHs bioremediation. All these findings in this study provide a theoretical basis and available microbial resource for bioremediation of PAHs-contaminants in the seagrass ecosystem.

Abstract:[Background] Marine microorganisms flourishing in diverse marine environments are widely recognized as rich sources of natural products. [Objective] Based on a Streptomyces sp. MMHS020 strain isolated from marine sediment, this study aimed to optimize fermentation conditions for abundant metabolites, and exploit the potential of the strain in antibacterial and antitumor activities. [Methods] Using a one strain-many compounds (OSMAC) approach, active metabolites were produced by strain MMHS020. Antibacterial activity for six indicator bacteria strains were traced using two-layer plate method. The metabolites were separated and purified by silica gel column chromatography, Sephadex column chromatography, and preparative chromatography. The compounds were elucidated by means of spectral analysis including ESI-MS, 1H-NMR, and 13C-NMR. [Results] Strain MMHS020 could produce diverse metabolites of antibacterial activity to inhibit the growth of all indicator bacteria such as Bacillus subtilis, Mycobacterium tuberculosis, and Micrococcus luteus when cultivated under high salt condition. Three compounds: nocardamine (1), ergosterol (2), and staurosporine (3) were isolated from the fermentation broth of strain MMHS020. Staurosporine was of inhibitory activity to Candida albicans, and nocardamine for the others. [Conclusion] Marine-derived Streptomyces sp. MMHS020, which produces a variety of bioactive metabolites, could be potentially developed as a novel antimicrobial agent.

Abstract:[Background] The microbial community composition at the interface has become one of the research hotspots in the field of microecosystem. [Objective] The objective of the study is to explore the spatial distribution of bacterial community river-lake ecotone of Poyang lake during dry season. [Methods] Eleven typical sampling points in the Poyang lake river-lake ecotone were selected to collect water samples for analyzing physical and chemical indicators. The 16S rRNA gene sequence data of the above samples were obtained by PCR. The diversity and richness of microbial communities were calculated and compared of 11 sampling sites. According to the Beta diversity distance matrix, the similarity tree diagram was used to cluster the samples to explore the microbial distribution in the Poyang lake river-lake ecotone. The relationship between physical and chemical factors and microbial community distribution was studied based on redundancy analysis (RDA). [Results] The Poyang lake river-lake ecotone water was slightly acidic, and TN content exceeded standard V, and the content of TP fluctuated between the standards of II, III and IV. The composition of dominant species of bacteria in the interlaced zone of Poyang lake is roughly similar except the difference of relative abundance. Microbial community structure at phylum level was Proteobacteria (36.18%), Firmicutes (22.18%), Bacteroidetes (17.06%) and Actinobacteria (8.87%). The proteobacteria in the water was dominated by γ-proteobacteria, and the β-proteobacteria was the sub-dominant flora. At the genus level, other geniuses of Actinobacteria had the highest relative abundance (11.4%). The microbial diversity index (Ace, Chao1, Shannon and Simpson) of Le?an River (R9) and confluence zone of Poyang lake and Yangtze river (H11) was higher than others, Wanjia bridge (N2), confluence zone of Poyang lake and Ganjiang (W6) and Yaohu lake (Y10) microorganisms has the lowest diversity index. The composition of microbial community was divided into two categories. The composition of Poyang lake Dahuchi reserve (W7), Le?an river (R9) and confluence zone of Poyang lake and Yangtze river (H11) were similar, and the composition of the other 8 samples was similar. The main environmental factors affecting the distribution of microbial communities were pH (P=0.735 2), TN (P=0.761 4) and TP (P=0.612 8). [Conclusion] The spatial distribution of bacterial communities in the river-lake ecotone of Poyang Lake in the dry season was obviously different. The spatial and geographical differences superimposed on the disturbance of human activities affected vegetation, hydrology, eutrophication degree, etc., thus causing differences in physical and chemical indicators of water, and then affecting the composition of bacterial communities, the composition of bacterial community was similar in areas with similar physical and chemical indexes. The bacterial diversity was low in the area with serious eutrophication. The study is helpful to understand the structure and function of Poyang lake ecosystem, provide technical support for water environment management and ecological protection of Poyang lake, and of great significance to maintain the ecological balance of Poyang lake.

Abstract:[Background] In Zhejiang province, China, the male form of cicada that is called the “male cicada flower” (Dujiaolong) is more often identified as female form (Isaria cicadae Miquel). So, it is necessary to distinguish them. [Objective] The theoretical basis for the identification of Isaria cicadae Miquel and Dujiaolong is provided by the difference of morphology and rDNA ITS sequence. Meanwhile, to further understand these two species, we analyzed the composition and function of bacterial community in sclerotia. [Methods] Technology of strains extraction and purification was conducted to obtain Isaria cicadae Miquel and Dujiaolong. Morphological characteristics of the cells which sporulate spores from these two entomopathogenic fungi were identified by microscope. With the technology of high-throughput sequencing, we analyzed the composition and function of bacterial community in sclerotia. [Results] The “cicada flower” (Chan-hua) was identified as Isaria cicadae, Dujiaolong was identified as Tolypocladium dujiaolongae. At the level of bacterial genus, the dominant bacteria in the sclerotia of Isaria cicadae Miquel is Achromobacter, a genus that is unclassified in Diplorickettsiacea, Rhizobium. In Tolypocladium dujiaolongae, the sclerotia has some potential pathogenic bacteria (e.g. Sphingobacterium and Serratia). Based on the bacterial COG database, the function of Isaria cicadae and Tolypocladium dujiaolongae was similar to each other. Meanwhile, the KEGG Pathway abundance of Isaria cicadae and Tolypocladium dujiaolongae was close. The 24-functional-gene families of these two species in sclerotia’s bacterial community were closely related to matter translocation and metabolism. The result show that the bacteria were highly related to metastasis. [Conclusion] Isaria cicadae Miquel is different from Dujiaolong. And the composition of bacterial community of these two species in internal sclerotia is different. The bacteria are mainly involved in the metabolic process of the two entomopathogenic fungi. Due to the pathogenic bacteria groups in the sclerotia of Tolypocladium dujiaolongae, the food safety of the “Tolypocladium dujiaolongae” should be skeptical when it is compared with Isaria cicadae Miquel.

Abstract:[Background] Bacillus subtilis can form biofilm by clustering, and biofilm plays an important role in the removal of heavy metals. [Objective] The purpose of this study was to examine the interactions of Bacillus subtilis B12 biofilm and lipopeptide compounds and cadmium removal, investigating the mechanism of B. subtilis B12 in alleviating Cd (CdSO4) stress. [Methods] Firstly, the effect of Cd stress on the formation of strain B12 biofilm was investigated. The lipopeptide compounds secreted by B12 strain under Cd stress were extracted, purified and identified by acid precipitation, reversed-phase high performance liquid chromatography (RP-HPLC) and liquid mass spectrometry (LC-MS). The effects of this major component on the biofilm formation and Cd adsorption of B. subtilis B12, Sinorhizobium meliloti Mr40 and B. amyloliquefaciens P29 were investigated. [Results] When 0?1.0 mg/L CdSO4 was applied in Msgg media, the dry weight of B. subtilis B12 biofilms increased significantly. Cd stress promoted the secretion of lipid peptide compounds by strain B12, and the content of surfactin was increased. In the Msgg media with 0.5 mg/L Cd concentration, biofilms dry weight of strains B12, Mr40, P29 were increased by 84.1% to 126.9% significantly when the strains were exposed to surfactin compared to control medium, whereas the planktonic cells counts were reduced significantly from 46.9% to 55.3%. Meanwhile, Cd removal rate of three strains were significantly increased by 23.0%–36.1%, biosorption capacities of Cd onto the strains biofilms significantly increased by 46.8% to 68.1%. [Conclusion] These findings suggest that B. subtilis B12 under exposure to Cd could trigger the effect of stronger surfactin and biofilm formation, and subsequent increased Cd absorption of the biofilms, thereby protecting them from Cd stress.

Abstract:[Background] Siderophore-producing bacteria (SPB) is a kind of growth-promoting microorganism with high heavy metal resistance, and its application in soil remediation of heavy metal contaminated soil has attracted increasingly attentions. [Objective] To provide organism resources for remediation of heavy metal cadmium contaminated soil; To investigate the effect of SPB on seed germination of ryegrass under cadmium stress. [Methods] the soil that isolated the bacteria was collected from Hongxin Mining Area, Linze county, Gansu province, a bacteria is capable of both producing siderophore and cadmium-resistant was obtained by isolating and purificating of microorganisms technology, and the identifying of this strain was used 16s rRNA gene sequence, and the structure type of chelating groups of siderophore, the growth curve and siderophore production curve of the strain were measured, the fluorescence intensity and ultraviolet spectrum of the siderophore were determinated after separating and purificating from the culture of this bacterium. Finally, the effects of siderophore and its producing bacteria on the germination of ryegrass under cadmium stress were investigated. [Results] The bacteria was identified as Pseudomonas sp. W-STS-8 and it could secrete a yellow-green siderophore—pyoverdine, which has two types chelating groups structures, hydroxamates type and catecholates type. The yield of siderophore reached its maximum value (68%) at the late of the stationary phase, and the yield of siderophore was positively correlated with the biomass of the strain. After separating and purificating of siderophore, the fluorescence could be observed under UV light (254 nm), and the characteristic absorption peak of ultraviolet spectrum was at 400 nm. By studying the effects of siderophore and its producing bacteria on the germination of ryegrass under cadmium stress, the result showed that compared with the control group, the strain culture and its siderophore showed remarkable effect, the seed germination rate of ryegrass increased by 73.14% and 150.92%, respectively. [Conclusion] This strain is expected to provide microbes resources and scientific basis for ecological remediation project by further study, which related to microbial-plant combined remediation of soil contaminated by cadmium.

Abstract:[Background] The Mount Everest area has extreme environmental conditions such as cold, low temperature and high doses of radiation. There is no report on the study of lithophilous microorganisms on the northern slope of Mount Everest. [Objective] To carry out research on the lithophilous microorganisms on the north slope of Mount Everest, clarify the diversity of culturable bacteria from the lithophilous habitat on the northern slope of Mount Everest, and develop resources of anti-ultraviolet radiation strains on the northern slope of Mount Everest. [Methods] The culturable method, 16S rRNA gene sequence analysis method and ultraviolet radiation were used to study the diversity of culturable lithophilous bacteria on the northern slope of Mount Everest and the ability of resistance to ultraviolet radiation. [Results] A total of 52 lithophilous bacteria were isolated from the lithophilous habitat on the north slope of Mount Everest, which were classified as Actinobacteria, Firmicutes, Proteobacteria, and Bacteroidetes. Actinobacteria and Proteobacteria are the dominant bacteria phyla, Sphingomonas, Arthrobacter, and Streptomyces are the dominant bacterial genera, two strains are potential new species. Two strains with higher resistance to ultraviolet radiation were selected from the isolated and identified strains, namely Bacillus ZFBP4009 and Streptomyces ZFBP1009. [Conclusion] The lithophilous environment on the north slope of Mount Everest contains rich diversity of lithophilous bacteria, and the isolated strains have outstanding the ability of resistance to ultraviolet radiation, which provides data support and strain resources for revealing the distribution characteristics of microorganisms in related extreme environments and the development of extreme environment microbial resources.

Abstract:[Background] Hypolithic biological soil crusts (BSCs) in the Gobi desert are colonized and multiplied by under-rock organisms, widely exist under quartzite, and play an important role in the material cycle of related ecosystems. The bacterial community structure was greatly shifted with the change of spaces and different type of soils. Nitrogen-fixing bacteria are the main driving force for the formation and development of hypolithic BSCs. The central gobi has a wide area and as a representative of the temperate gobi. However, there are no research reports on the community structure and diversity of nitrogen-fixing bacteria in hypolithic BSCs. [Objective] To explain the community structure, diversity and factors influencing nitrogen-fixing bacteria in hypolithic BSCs. [Methods] The methods included Miseq to perform high-throughput sequencing of the nifH gene; bioinformatics to analyze the community structure and diversity of nitrogen-fixing bacteria and its influencing factors based on the nifH sequence, and CoNet software to map species co-occurrence networks to discover key species. [Results] In hypolithic BSCs, the dominant phyla were Cyanobacteria (47.20%?69.90%) and Proteobacteria (27.47%?48.91%), and genera were Scytonema (45.05%?69.09%), Skermanella (10.26%?20.48%) and unclassified genera (13.72%?22.00%). The species richness in September was higher than that in May, but there was no significant difference between the two months. Among others, available nitrogen was the soil physical and chemical factor that had the greatest impact on the composition of nitrogen-fixing bacterial communities in the hypolithic BSCs. There was a strong interaction between the microorganisms in nitrogen-fixing bacteria under the rock, and the relationship was mainly coexistence (about 66.98%). In the CoNet network, the nodes with high degree of centrality, close centrality and betweenness centrality all belonging to alphaproteobacteria. [Conclusion] Cyanobacteria and Proteobacteria were the most dominant nitrogen-fixing bacteria in hypolithic BSCs of Central Gobi. alphaproteobacteria was the key species stabilizing the nitrogen-fixing bacterial community and may be the main nitrogen fixers. This study provided a basic basis for understanding and using the nitrogen-fixing bacteria associated with hypolithic BSCs.

Abstract:[Background] D-mannose with many functional activities has been widely used in food, medicine, feed, etc. D-mannose isomerase can catalyze the reversible reaction between D-fructose and D-mannose, and has application potential in the enzymatic preparation of D-mannose. [Objective] The D-mannose isomerase gene (ssMIaseA) from Streptomyces sp. was cloned and expressed in Escherichia coli, and its enzymatic properties were studied and used to prepare D-mannose. [Methods] The D-mannose isomerase gene (ssMIaseA) from Streptomyces sp. was cloned and the recombinant expression plasmid pET-28a-ssMIaseA was constructed and expressed into E. coli BL21(DE3). After purification by Ni-NTA affinity chromatography, the enzyme properties were determined, and the preparation of D-mannose from SsMIaseA was analyzed by high performance liquid chromatography. [Results] SsMIaseA shared the highest homology of 60.2% with ManI from Thermobifda fusca. The specific activity of the enzyme was 525 U/mg, and the molecular weight was about 45 kD. Its optimal pH and temperature were 7.5 and 45 °C, respectively. It was stable in the range of pH 6.5?10.0 and below 45 °C. It had the highest catalytic activity for mannose, followed by D-fructose, D-talose and D-tagatose. SsMIaseA was used to convert 600 g/L D-fructose and the reaction reached equilibrium at 8 h, producing 185 g/L D-mannose with a conversion rate of 31%. [Conclusion] SsMIaseA as a new D-mannose isomerase has potential in the enzymatic preparation of D-mannose.

Abstract:[Background] Anthranilate synthase, one common enzyme in plants and microbes, is involved in the biosynthesis of tryptophan and auxin, and plays an important role in growth and development, together with the response to multiple stresses. Tolypocladium guangdongense is a new cordyceps resource only found in South China, and has a great exploitation value. [Objective] Dissect the gene features of TgtrpE, and explore the expression pattern of TgtrpE at differential developmental stages and temperature stress conditions in T. guangdongense. [Methods] The coding sequences of TgtrpE were cloned from T. guangdongense and used for bioinformatic and phylogenetic analysis. Real-time fluorescence quantitative PCR (RT-qPCR) was performed to analyze the expression pattern of TgtrpE under differential developmental stages and temperature stresses. [Results] The sizes of TgtrpE were 1 613 bp (DNA) and 1 563 bp (cDNA) in length, respectively. It encodes 521 amino acids with a molecular weight approximate of 56.86 kD. The phylogeny result showed that the TgTrpE protein of T. guangdongense was clustered into one clade with those of ascomycetes fungi, and had a higher similarity with Tolypocladium paradoxum and Tolypocladium capitatum. RT-qPCR results showed that compared to the mycelial stage, TgtrpE was significantly up-regulated at primordium and young fruiting body stages, whereas TgtrpE showed a clear downregulation expression at mature fruiting body stage and in the response process of cold and heat stresses. [Conclusion] TgtrpE may play an important role in the processes of primordium formation, fruiting body development and temperature stresses.

Abstract:[Background] Isaria cateinannularis is an important entomogenous fungus, and its biocontrol efficiency in the field is affected by the stress of many environmental factors. [Objective] Hsp100/ClpB is a class of ATP-dependent Hsp100 family protein, to clone two crucial Hsp100/ClpB (heat shock protein, casein lytic proteinase B) family genes IcHsp104 and IcHsp78 from Isaria cateinannulata, and to explore its role in response to different temperatures and concentrations salt stress. [Methods] The Hsp100 family genes were analyzed and screened by BLAST method using transcriptomic database obtained in early stage. RT-PCR technologies were used to verify the open reading frame (ORF) sequence of Isaria cateinannulata Hsp100 genes. The amino acid structure, phylogenetic tree, functional domain and tertiary structure of Isaria cateinannulata Hsp100 genes were analyzed by molecular bioinformatics analysis software. The expression of Isaria cateinannulata Hsp100 genes were detected by RT-qPCR technology after the fungus were treated with different temperature and salt concentration. [Results] A pair of Hsp100/ClpB genes Hsp104 and Hsp78 were screened and named IcHsp104 and IcHsp78, which encoded 923 and 805 amino acids, and their molecular weights were 103.199 kD and 88.805 kD, respectively. The relationship of both genes were close to Isaria spp., Beauveria spp. and Cordyceps spp., but it showed lower similarity between the two genes. The proteins encoded by the two genes were classic AAA+-ATPase family proteins, and the tertiary structure was mainly by alpha helix. In addition, after the treatment of high and low temperature, the expression levels of both genes were up-regulated, and increased more significantly with the extension of treatment time. Additionally, the effect of high temperature stress was significantly stronger than the low temperature stress. Then, in terms of the treatment of different concentrations of sodium chloride, the expression levels of both genes were up-regulated in the low concentration stress, while they were inhibited in the high concentration stress. [Conclusion] The IcHsp104 and IcHsp78 genes from Isaria cateinannulata play an important role in the response to external temperature and salt stress, those findings provide a theoretical basis for the further mechanism studies on Isaria cateinannulata responding to environmental stress.

Abstract:[Background] Burkholderia HQB-1 has good control effect on banana fusarium wilt (Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4)). [Objective] The active compound was separated from the fermentation broth of HQB-1 strain, and the active compound was detected by HPLC-MS to obtain the monomer compound with good biocontrol effect. [Methods] HQB-1 strain was fermented in large quantities, and then the fermentation broth was separated and purified. The active compounds were identified by HPLC-MS and NMR. [Results] The protein from fermentation broth of HQB-1 strain had no inhibitory effect on Foc TR4. The catechol type iron carrier rather than hydroxamic acid type iron carrier was produced from HQB-1 strain. HQB-1 strain fermentation broth was centrifuged, concentrated and dried to obtain ethyl acetate extract (crude extract), which was then fully adsorbed by macroporous resin column. The components 1?3 were obtained after eluting by 30%, 60% and anhydrous methanol, and the corresponding inhibitory rate to Foc TR4 was 10.06%, 27.82% and 51.40% respectively. The component with the highest inhibitory rate was selected, and the yellow green crystal was obtained through silica gel column chromatography. The compound had a maximum absorption peak at 365 nm wavelength. The antibacterial activity compound was identified as phenazine-1-carboxylic acid (PCA), after the comparative analysis of NMR spectrum with SciFinder and SDBS information database. The minimum inhibitory concentration (MIC) of PCA to Foc TR4 was the lowest, only 1.563 μg/mL, indicating that PCA had a strong inhibitory effect on Foc TR4. [Conclusion] The active compound PCA isolated from HQB-1 strain had the biocontrol effect on banana fusarium wilt.

Abstract:[Background] Watermelon Fusarium wilt is a soil-borne disease caused by Fusarium oxysporum f. sp. niveum, and one of the most serious diseases in watermelon production. Identification of antagonistic microorganisms is necessary to develop biocontrol agents. [Objective] To isolate and identify effective biocontrol strains against watermelon Fusarium wilt, and investigate the inhibitory effect, ultimately provide candidates for developing biocontrol agents. [Methods] We isolated bacteria from the rhizosphere soil of watermelon. Antagonistic bacteria were screened by plate confrontation and greenhouse bioassay method. Morphological observation and gyrB gene sequence homology analysis were performed to characterize the strains isolated. The antagonistic factors (cellulase, protease, chitinase, β-1,3-glucanase) of antagonistic bacteria were determined by differential medium, and the effects of antagonistic bacteria fermentation liquid on the spore germination and hypha growth of Fusarium oxysporum f. sp. niveum were determined. Finally, the control effect of antagonistic bacteria on watermelon Fusarium wilt was determined in the field. [Results] An antagonistic strain SFJ11 against watermelon wilt was selected by means of plate confrontation and greenhouse assay. The strain was identified as Bacillus amylolyticus by morphological identification and homology analysis of gyrB gene sequence which could secrete protease and cellulase. The 20% fermentation broth of antagonistic bacterium SFJ11 could almost completely inhibit the growth of mycelia, and inhibit the germination of 95.44% of spores of Fusarium oxysporum f. sp. niveum. The control effect of SFJ11 on watermelon Fusarium wilt was 78% in field experiment. [Conclusion] Strain SFJ11 had a notably biological control effect on watermelon Fusarium wilt, and it would be a potential biocontrol agent.

Abstract:[Background] Some Burkholderia are important plant rhizosphere growth-promoting bacteria, which can inhibit plant pathogens and promote plant growth. [Objective] This study is to investigate the antagonistic ability of phosphate solubilizing and growth-promoting bacteria B. multivorans WS-FJ9 against different forest pathogens. [Methods] The antagonistic effect of WS-FJ9 strain against five forest pathogenics, the changes of mycelial contents of pathogenic fungi and oomycetes treated by strain WS-FJ9, the prediction of secondary metabolites and the antagonistic activity and stability of the fermentation broth were studied by using dual culture, colorimetric method, antiSMASH 5.0 online prediction site and mycelium growth inhibition rate method, respectively. [Results] The strain WS-FJ9 had different inhibitory effects against the five forest pathogens, in which the suspension had the best inhibitory effect against Phytophthora cinnamomi with the inhibitory zone width up to 14.82±0.20 mm. The fermentation broth of WS-FJ9 had significant inhibitory effect against Phomopsis macrospore and Sphaeropsis sapinea, and the inhibition rates were 62.22% and 62.78%, respectively. The contents of malondialdehyde (MDA), reducing sugar and soluble protein in the mycelia of pathogenic bacteria were increased after the treatment of sterile fermentation filtrate. The genome of the WS-FJ9 strain contained 27 different gene clusters encoding secondary metabolites, including genes encoding siderophores, bacteriocins and antibiotics. The antifungal activity of the fermentation broth of the strain was not affected under high temperature, ultraviolet irradiation, protease treatment, extreme acid and alkali treatment. [Conclusion] B. multivorans WS-FJ9 could be potentially used as biocontrol agent against forest pathogens.

Abstract:[Background] There are many studies on the use of antagonistic bacteria to control crop diseases, but there are few studies on the effects of secondary metabolites of antagonistic bacteria on cotton rhizosphere soil microbial community. [Objective] To investigate the effects of Verticillium dahliae resistant metabolites of Bacillus subtilis J-15 on the diversity of soil fungi in cotton fields, and to evaluate the ecological security of soil microorganisms for controlling Verticillium wilt of cotton with Bacillus subtilis J-15 and its secondary metabolites. [Methods] The cotton field in Manas area of Northern Xinjiang was selected as the soil sampling point, and 10 sampling points were randomly selected for mixing. After treated with the substance that secondary metabolites of Bacillus subtilis J-15 against Verticillium dahliae for a certain time, the total DNA of soil sample was extracted, and then the ITS1?ITS2 region of fungi in the samples was used to sequence by Illumina Hiseq high-throughput technology, and the effects of the secondary metabolites of Bacillus subtilis J-15 against Verticillium dahliae on the diversity of soil fungi were analyzed. [Results] At the 97% similarity level, the OTU number, Chao1 and ACE abundance index of fungi in the samples after 10 and 30 d of treatment were higher than those of the untreated control group at the same time, while Simpson index was significantly lower than that of the control group. From the community composition analysis, compared with the control group, the relative abundance of dominant fungi in Ascomycota and Mortierellomycota, such as Mortierella and Tricharina, was significantly increased in soil samples treated with secondary metabolites of J-15, while the abundance of Verticillium and Fusarmm, which were higher than 1%, were significantly lower. [Conclusion] Secondary metabolites of J-15 resistant to Verticillium dahliae had significant effect on soil fungal community and abundance in farmland, but did not change the structure of soil fungal community affecting agricultural production.

Abstract:[Background] The scales of red-hearted dragon fruit appear yellowing, wilting and moldy stalks when storing at room temperature for 3 days. The fruit rot rate is higher than 55% for 8 days, as well as 95.5% for 16 days. [Objective] To isolate and identify the main spoilage microorganisms and screen the antagonistic strains with the best antiseptic effect of red-hearted dragon fruit. [Methods] The spoilage microorganisms of red-hearted dragon fruit were isolated by pure culture. The dominant spoilage bacteria inoculated into dragon fruit were identified based on physiological and biochemical characteristics combined with sequences analysis of bacterial 16S rRNA gene、fungal rDNA ITS and bioinformatic analysis. 11 Bacillus subtilis strains as the tested antagonistic strains were used as biological antisepsis for dragon fruit. [Results] A total of 60 spoilage bacteria were isolated from naturally decomposed red-heart dragon fruit, of which bacteria accounted for 38.33% and fungi accounted for 61.67%. All of them were inoculated into red-hearted dragon fruit, and then 2 spoilage bacteria causing 100% rotten were found when storing at room temperature for 27 days. The two spoilage bacteria were identified as P. expansum named BP15 and E. nigrum named BP25. The plate antagonism test showed that the inhibitory rate of Bacillus amyloliquefaciens 10075 to the BP15 and BP25 strains was the most significant, which reached 60.59% and 84.73%, respectively. The 10075 filtered sterile supernatant with a concentration of 90% was used to inhibit BP15 and BP25, of which the inhibitory rate were 54.32% and 90.00%, respectively. However, heat treatment of the supernatant resulted in the inhibitory rate of BP15 and BP25 decreasing by 1.30% and 12.43%, respectively. With 90% 10075 filter sterilization supernatant spraying on dragon fruit, the biological antisepsis characteristic was higher than 30% after 10 days’ treatment. The research provides an effective biological antisepsis method for storage and preservation of dragon fruit. [Conclusion] Dragon fruit has extremely high economic value, nutritional value and medicinal value, however it is easy to rot at room temperature. The research can provide an effective biological antisepsis method for the storage and preservation of dragon fruit at room temperature.

Abstract:[Background] Bluetongue virus (BTV) belongs to arbovirus that infects ruminants and varies frequently due to gene reassortment. [Objective] To explore the correlation of gene reassortment and phenotypic variation of BTV caused by reassortment of the Seg-2 and Seg-6 between virulent BTV-16 strain and the weakly pathogenic BTV-4 strain. [Methods] The full genome sequence of BTV-16/V158 was obtained by full-length cDNA amplification (FLAC) and next generation sequencing (NGS). Eukaryotic expression plasmids of BTV were constructed and their expressed proteins were verified through immunofluorescence assay (IFA) and Western Blot (WB). Reverse genetic system of BTV was established through RT-PCR, in vitro transcription and cell transfection, and reassortant BTVs were rescued using the established system. The differences in biological characteristics between parental and reassortment BTV were compared through viral plaque formation assay, proliferation curve analysis, and serum neutralization test. [Results] The genome of BTV-16/V158 strain was 19 186 bp in length, which shared the closest relationship with the Chinese and Indian BTV-16 strains. The expressions of target proteins were confirmed by IFA and WB in the cells which were transfected with eukaryotic plasmids expressed VP1, VP3 and NS2 of BTV. BTV strain, named as BTV-16/V158-RG, was successfully recovered by transfecting BHK-21 cells with BTV eukaryotic expression plasmids and genomic ssRNA, which showed consistent biological characteristics with its parental virus BTV-16/V158. Furthermore, reassortment virus, named as BTV-16/V158-RG (BTV-4/S2, S6), which carried the Seg-2 and Seg-6 genes of BTV-4 strain in a backbone of BTV-16/V158 was successfully rescued. Compared with its parent virus, BTV-16/V158-RG (BTV-4/S2, S6) showed smaller viral plaques and weak proliferation on BHK-21 cells, with its serotype converted from BTV-16 to BTV-4. [Conclusion] the reverse genetic system of Chinese BTV-16 strain was successfully established. Reassortment of the Seg-2 and Seg-6 altered the proliferation and serotype of the viruses.

Abstract:[Background] With the carrying out of the antibiotics prohibition order, it is urgent to find a safe substitute for antibiotics. [Objective] The study aimed to explore the effects of the Pediococcus pentosaceus in finishing pigs. [Methods] 20 pigs were randomly divided into 2 groups with 2 replicates in each group and 5 pigs in each replicate. The pigs in control group were fed a basal diet, and the pigs in experimental group were fed with basal diet and Pediococcus pentosaceus (1010 CFU/kg), respectively. The experimental period was 28 days. [Results] The result data shows as follows: 1) There was no significant difference during two groups in the average daily gain (ADG), feed/gain(F/G) and average daily feed intake (ADFI) (P>0.05) during the experimental period. 2) It gained 1 036 OTUs by OTU cluster analysis, and they were clustered to 17 phyla, 23 classes, 37 orders, 67 families, 199 genus, 350 species. There was significant difference during two groups by principal co-ordinates analysis (PCoA) (P?0.05). At the phylum level, the relative abundance of Spirochaetes in group P was significantly higher than the group C (P?0.05). At the genus level, the relative abundance of Clostridium_sensu_stricto_1 and Terrisporobacter (P?0.05) in group P was higher than group C, Streptococcus (P?0.01), Lachnospiraceae_ XPB1014_group (P?0.05), Norank_f__p-251-o5(P?0.01) and Ruminococcaceae_NK4A214-group (P?0.05) was significantly lower than group C. The LEfSe (LDA effect size) results showed that 60 biomarkers were obtained when the LDA value was higher than 2.0, while 31 biomarkers were due to group P. The largest LDA value of bacteria in group P was Clostridiales, and that of group C was Streptococcus. 3) There was significant difference in positive and negative model by partial least squares discrimination analysis (PLS-DA) analysis (P?0.05), the two groups were divided completely. The metabolite analysis showed that the diphthamide, 2-hydroxymyristic acid, furanofukinin, dopaquinone, avocadene, N-(1-deoxy-1-fructosyl) proline and N-(1-deoxy-1-fructosyl) glycine up-regulated significantly (P?0.05) or extremely significantly (P?0.01) in group P, 24-dehydropro vitamin D3, Artonin U and 1alpha, 25-dihydroxy-9,11-didehydro-3-deoxy-vitamin D3, all down-regulated significantly (P?0.05) or extremely significantly (P?0.01). [Conclusion] In summary, the addition of pediococcus pentosaceus can optimize the structure of fecal microbiota in finishing pigs, improve the relative abundance of Clostridium_sensu_ stricto_1 and Terrisporobacter which due to disease-resistant, reduce the relative abundance of Streptococcus which is the opportunistic pathogen, improve the relative content of flavoring substance precursor (N-(1-Deoxy-1-fructosyl) proline, N-(1-deoxy-1-fructosyl) glycine), reduce the relative content of Vitamin D3 (24-dehydropro vitamin D3 and 1alpha,25- dihydroxy-9,11-didehydro-3-deoxy-vitamin D3). It has the potential function of growth-promoting and reducing disease.

Abstract:[Background] Aquatic pathogens restrict the healthy development of aquaculture; quorum sensing is closely related to the production of virulence factors. The characteristics of virulence factors regulated by quorum sensing is worthy of further study. [Objective] To explore the relationship between quorum sensing and bacterial diseases of Yellow River carp, and clarify the influence of quorum sensing on the characteristics of virulence factors. [Methods] The 16S rRNA gene was sequenced and the phylogenetic tree was constructed to determine the evolutionary status of the selected strains. The activity of extracellular protease was detected by skim milk plate method and azo casein method. The bacterial biofilm forming ability was determined by crystal violet staining. The producing ability of AI-2 and AHLs was determined by reporter strain BB170 and CV026, respectively. The effects of exogenous HSLs on extracellular protease ability and biofilm formation ability were detected. [Results] Hafnia sp. Z11 and Aeromonas sp. Z12 were evidenced with high levels of extracellular protease activity and biofilm formation ability, and could secrete AHLs signal molecules, which were density dependent. High concentration of C4-HSL and C6-HSL could increase the extracellular protease activity and biofilm formation activity of strain Z11 and Z12, respectively. [Conclusion] High concentration of quorum sensing factors (AHLs) can promote the extracellular protease activity of Hafnia sp. Z11 and Aeromonas sp. Z12, suggesting that the quorum sensing of these two bacteria may affect their virulence.

Abstract:[Background] Vibrio parahemolyticus is an important food-borne pathogen causing severe threats to public health. Toxin-antitoxin (TA) systems are widely distributed in the genomes of bacteria and archaea, and possess important biological functions. [Objective] To identify novel TA systems in V. parahemolyticus, and lay the foundation for exploring the underlying mechanism of bacterial pathogenicity and drug resistance from the aspect of TA systems. [Methods] The putative chromosomal type II TA systems in V. parahemolyticus were predicted by a web-based tool. The toxic effects of the putative toxins on Escherichia coli and the antitoxic effects of the corresponding antitoxins were assessed by growth curves analyses and spot dilution assays. Reverse transcription PCR was used to determine whether the genes encoding the toxin and antitoxin were co-transcribed. The homologous proteins of the newly identified TA system were determined by bioinformatics analysis. The regulation of their own promoters by the antitoxin and antitoxin-toxin complex was detected by LacZ reporter assay. [Results] Six putative chromosomal TA systems were identified in V. parahemolyticus. The product of the vp1820 gene (VP1820) had bactericidal activity against E. coli, which could be counteracted by the product of the vp1821 gene (VP1821). The genes vp1821 and vp1820 are co-transcribed. The vp1821-vp1820 locus encodes the YefM-YoeB TA system. The YefM antitoxin positively regulates the promoter, while the YefM-YoeB complex negatively regulates the promoter. [Conclusion] This study identifies a novel type II TA system in V. parahemolyticus, namely YefM-YoeB, and lays the foundation for further research on the role of this system in the pathogenicity and drug resistance of V. parahemolyticus.

Abstract:[Background] Bacillus amyloliquefaciens strain BS-3 is an endophytic bacterium from healthy rubber tree roots, and shows strong antimicrobial activity in vitro. The strain has the potential to be used as a biological fungicide. [Objective] To analyze the genome information of B. amyloliquefaciens BS-3 strain, to help further study the antimicrobial mechanism and secondary metabolites biosynthetic gene clusters of BS-3 strain. [Methods] The genome was sequenced using BGISEQ II platform and PacBio RS III platform, then analyzed using relevant software for genome assembly, gene prediction and functional annotation, prediction of secondary metabolite synthetic gene clusters. [Results] The genome is 3 870 130 bp with average GC content of 46.88%, which might code the potential 4 161 genes; and the genome of strain BS-3 had 92 tRNA; 28 rRNA; 10 sRNA; 122 tandem repeats, 98 minisatellites DNA and 2 microsatellites DNA. There were up to 2 875, 2 620, 1 885, 4 040 and 3 328 potential genes annotated with COG, GO, KEGG, NR and Swiss-Prot databases respectively. At the same time, 10 secondary metabolite biosynthetic gene clusters were also predicted, which might code the surfactin, fengycin, bacillaene, bacillibactin and other antibacterial substances. The sequencing data from this article are available in the GenBank database (accession No. CP060384). [Conclusion] This study provides basic data to analyze the internal causes of the biocontrol activity effect of strains BS-3 at the genomic level, and provides reference information for further understanding the secondary metabolic synthesis pathway of B. amyloliquefaciens. It is of great significance to the further study BS-3 strains.

Abstract:[Background] With the wide application and abuse of antibiotics, the “super bacteria” resistant to almost all antibiotics emerged. And clinically, bacteria resistant to tigecycline, the current last line of defense to treat “super bacteria” infections, had emerged too. [Objective] To screen tigecycline resistance genes from the soil and study the resistant mechanism, providing the reference for clinical antibiotic treatment. [Methods] Functional metagenomics technology was used to obtain tigecycline resistance clone, and subcloning and sequencing were used to identify the tigecycline resistance gene. The characteristics of physicochemical properties, protein secondary structure, transmembrane domain, and system evolution analysis of the resistant gene were analyzed by bioinformatics methods. Besides, the determination of minimum inhibitory concentration was performed. [Results] A gene encoding tetracycline resistance MFS efflux pump was identified and the E. coli harboring this gene showed resistance to tigecycline and tetracycline with the MIC values of 16 μg/mL and 32 μg/mL, respectively. The efflux activity of the protein was inhibited by 4 μg/mL of MFS efflux pump inhibitor CCCP. The predictive protein encodes 483 amino acids and belongs to hydrophobins and stable proteins. And it contained 14 transmembrane regions which formed a typical 14-times transmembrane spiral MFS efflux pump conserved domain. Phylogenetic tree analysis showed that the protein was located on different branches and showed low homology with other protein encoded by tigecycline resistance genes. [Conclusion] A tigecycline resistance MFS efflux pump gene was obtained using functional metagenomics technology. The protein encoded by the gene belonged to 14-times transmembrane spiral MFS efflux pump family, and this study provided reference on future study of the mechanism of tigecycline resistance.

Abstract:[Background] Vibrio parahaemolyticus is an important food-borne pathogenic microorganism. Type Ⅲ secretion system (T3SS) plays an important role in the pathogenic process of V. parahaemolyticus. The VscG protein encoded by the vscG gene is a chaperone protein in T3SS. The biological function of vscG gene has not been determined. [Objective] To analysis the effect of the vscG gene on the biological characteristics, a deletion strain and complement strain of the vscG gene were constructed and characterized. [Methods] We constructed the vscG gene mutant strain and complemented strain of POR-1 strain using the homologous recombination method. Then we analyzed the growth characteristics, biofilm formation, motility, hemolytic activity, cells adhesion and cytotoxicity. [Results] Compared with POR-1 strain, the growth characteristics and hemolytic activity of the deletion strain ΔvscG and the complementing strain CΔvscG were not significantly different. The biofilm formation ability of ΔvscG was reduced. The motility was enhanced of ΔvscG as compared with POR-1 and CΔvscG. Cell infection tests showed that the deletion of the vscG gene significantly reduced the adhesion and toxicity of V. parahaemolyticus to HeLa cells. [Conclusion] The vscG gene affects the motility and formation of the biofilm of V. parahaemolyticus, it plays an important role in the adhesion and cytotoxicity to HeLa cells, laying a foundation for further exploring the pathogenic mechanism of T3SS in V. parahaemolyticus.

Abstract:[Background] Methicillin-resistant Staphylococcus aureus (MRSA) is a common opportunistic pathogen in hospitals and the community, characterized by multi-drug resistance, high morbidity and mortality, and MRSA infection has become one of the common problems in the global medical community. [Objective] To study the antibacterial mechanism of rhubarb acid against MRSA. [Methods] To determine the minimum inhibitory concentration (MIC) of rhubarb acid on MRSA by two-fold dilution method; to determine the dynamic inhibitory effect of rhubarb acid on MRSA by MIC; to establish a biofilm model and determine the effect of rhubarb acid on viable bacteria in biofilm barrier, and to observe the effect of rhubarb acid by scanning electron microscope. The morphological changes of MRSA bacteria after the action of different concentrations of rhubarb acid; the effects of rhubarb acid on the depolarization and permeability of MRSA cell plasma membrane were determined by immunofluorescence staining and fluorescence analysis. [Results] The MIC of rhein on MRSA was 8 μg/mL; rhein had obvious inhibitory effect on the surviving bacteria in the biofilm, and under the effect of rhein, the morphology of the bacterial body was obviously wrinkled and damaged, and the severity of damage was positively correlated with the concentration; with the increase of rhein concentration and effect time, the fluorescence intensity changed obviously, and the permeability of the cell membrane changed. [Conclusion] Rhein mainly damaged the cell membrane of bacteria, thus inhibiting the growth and reproduction of bacteria.

Abstract:[Background] Inappropriate gestational weight gain is associated with disorder of pregnant women’s blood glucose and lipids which are closely related to maternal-fetal metabolic diseases. Gut microbiota coordinates the absorption of nutrients by intestinal cells, which may affect maternal-fetal glucose and lipids level. [Objective] To observe the constitution and diversity of gut microbiota from pregnant women with different gestational weight gain, and explore microbiota which may be related to blood glucose and lipids in the third trimester pregnancy. [Methods] A total of 34 excrement samples were selected from pregnant women with different gestational weight gain. 16S rRNA gene sequencing in the V3?V4 region of gut microbiota was acted by high throughput MiSeq method to analysis the constitution and diversity of gut microbiota. KEGG analysis was used to study the metabolic pathway change of different gestational weight gain. By correlations analysis, we can predict gut microbiota associated with gestational weight gain, maternal body mass index and blood glucose and lipids in the third trimester pregnancy. [Results] There was no significant difference in the diversity and constitution of gut microbiota, but the percentage of differential gut microbiota has changed. Correlation analysis found that Ruminococcaceae_UCG-014 sp. was negatively correlated with maternal body mass index (BMI) in the third trimester and gestational weight gain, Lachnospira spp. negatively correlated with blood glucose in the third trimester, Alitipes spp. and Ruminococcus_torques_group spp. were negatively correlated with maternal triglycerides in the third trimester, Parabacteroides spp. positively correlated with high density lipoprotein in the third trimester while negatively correlated with birthweight. Besides, Mucispirillum spp. was negatively correlated with high density lipoprotein in the third trimester. KEGG analysis found that gut microbiota with average gestational weight gain was significantly higher in 31 metabolic pathways including carbohydrate, lipid and amino acid metabolism than lower and higher gestational weight gain. [Conclusion] Gut microbiota may affect blood glucose and lipids level by affecting the metabolism and transport of nutrients, thereby affecting weight gain during pregnancy.

Abstract:Profiting from the rapid development of molecular biology technology, functional genomics plays an increasingly important role in analyzing microbial polysaccharide synthesis pathways. Various gene mining methods and genomics analysis tools facilitate the study of genes responsible for microbial polysaccharides synthesis. Here, we summarize the recent studies in biosynthetic pathway of versatile microbial polysaccharide biosynthesis and the key enzymes involved, the techniques and software package useful for gene mining and function verification. This review will provide a reliable technical reference for crucial genes verification in microbial polysaccharide synthesis and feasible solutions in strain engineering with elevating production titer.

Abstract:Pseudomonas aeruginosa (P. aeruginosa), an obligatory aerobic non-fermented Gram-negative bacterium, is one of the common opportunistic pathogens of nosocomial infection. P. aeruginosa can cause severe infection such as respiratory tract, urinary tract, burn wounds and bacteremia. The antibiotic resistance of P. aeruginosa spread widely, which brings difficulties to clinical treatment. Essential genes are indispensable genes for organisms to grow. Investgation of P. aeruginosa essential genes could help us to understand the basic characteristics of bacteria such as growth and virulence, and could also help us to screen new targets of antibacterial agents. This paper will summary the progress of P. aeruginosa essential genes, including basic physiological characteristics of P. aeruginosa, the research methods of essential genes and the progress and significance of P. aeruginosa essential genes.

Abstract:Legionella pneumophila secretes a large number of effectors into the cytoplasm through its unique Dot/Icm type-IVB secretion system, among which there are more than ten effectors known to participate in regulation of host ubiquitination. These effectors achieve the purpose of evading surveillance by the host immune system and proliferation by regulating the host ubiquitination pathway. The effectors involved in regulating the host ubiquitination pathway include AnkB, SidC, LubX, SidH, LegU1, GobX, RavD, DupA, DupB, SidJ, Ceg23, MvcA, MavC and SidE family proteins. Through the gradually in-depth study of the functional experiments and structural biology of these effect factors, their relatively complete molecular mechanism has gradually been revealed. This article reviews several important L. pneumophila effectors and their biological structure and molecular mechanism, which is helpful to comprehensively understand the complex process of Legionella pneumophila involved in regulating the host ubiquitination system.

Abstract:Bacterial colonization refers to the phenomenon that bacteria from different environments touch the body, then adhering, growing and multiplying on certain parts. Both the protective effect of commensal bacteria on the intestinal tract and the infection caused by pathogenic bacteria often depend on bacterial colonization. At present, the translation of “bacterial colonization” is inconsistent in a lot of textbooks and journals, and there is a mixed use. No clear conclusion has been reached as to which is the correct use. In order to avoid the above problems and provide a reference for the correct translation of “bacterial colonization”, this paper analyzed and discussed the conditions, process, significance and current usage of “bacterial colonization”, and finally determined the suitable translation for the “bacterial colonization”.

Abstract:Gas vesicles (GVs) are intracellular organelles with a rigid hollow structure completely composed of proteins. It can provide buoyancy for aquatic microorganisms, and is very important for their survival under adverse environment or stress conditions. In recent years, GVs with diverse functions in nonaquatic microorganisms such as Serratia and Streptomyces have also been reported. Gas vesicle biosynthetic gene clusters in different bacteria have presented distinct characteristics, as well as the corresponding regulation mechanisms for GVs biosynthesis. This review summarizes the basic characteristics of GVs from various bacterial species, including their fundamental physiological functions, biosynthetic and regulation mechanisms, as well as the applications of GVs in biotechnology. Finally, the biosynthetic studies of GVs in important industrial microorganism Streptomyces, and the potential applications of recombinant GVs are prospected.

Abstract:Seed is the reproductive organ of plants, and there are a certain number of endophytes colonized in the seed. The seed endophytes become the earliest colonized microorganisms in the tissue of new plants through vertical propagation, which plays a decisive role in the formation of endophytic community of successive generations of plants, and plays an important role in plant stress resistance. In this paper, the relationship between seed endophytes and heavy metal resistance of host plants and their functional mechanisms are reviewed, and the future research directions are prospected.

Abstract:It has been unequivocally proved that the occurrence and development of oral diseases are strongly associated with the imbalance of oral microbiota. Probiotics are live microorganisms that confer health benefits on the host, which exert the probiotic efficacy by the process of secreting antibacterial substances, interfering with the colonization of pathogenic bacteria, modulating the expression of virulence-associated genes, modulating host immune responses, regulating oxidative stress response, involving nitrate-nitrite-nitric oxide pathway, and adjusting the pH value of biofilms. Studies have found that probiotic therapy could reduce the risk of dental caries, promote the periodontal status, and improve the therapeutic effect of oral mucosal diseases, which is expected to be the potential way to prevent and treat oral diseases. This article reviews the researches progress on the relationship between probiotics and oral microecological regulation in recent years.

Abstract:Salmonella is one of the most important foodborne pathogens. Due to food matrix protection, some Salmonella can survive from heat stress. However, the bacterial cell structure, physiological characteristics, gene and protein expression commonly varied because of heat stress and/or cell response, and subsequently, these survived cells can continuously contaminate the raw food materials and processing environment. In this paper, the changes of cell morphology, cell components, cell wall and cell membrane structure of Salmonella before and after heat stress were summarized. Meanwhile, the molecular mechanism of DNA damage, heat shock response, stress resistance and pathogenicity caused by the survived Salmonella under heat stress was discussed based on gene and protein expression.

Abstract:The reversible phosphorylation modification of protein plays a crucial role in the life activities of fungal cells. The phosphorylation and dephosphorylation processes are coordinated with each other. The dephosphorylation of serine/threonine sites in protein is mainly catalyzed by protein phosphatase 2A (PP2A). The catalytic subunit, regulatory subunit and structural subunit are combined into an active trimeric holoenzyme form when PP2A is functioning. This article will take the model fungi Saccharomyces cerevisiae, Schizosaccharomyces cerevisiae, and the human conditional pathogen Candida albicans as examples to introduce the research progress of PP2A in fungal cells, helpful to understand the importance of dephosphorylation in regulating their life. In addition, we also analyzed the unclear problems in the research field of PP2A, and proposed possible research ideas.

Abstract:The biomineralization remediation technology has great value and broad prospect with eco-friendliness, wide sphere of application, and excellent stability on the removal of low concentration uranium-containing wastewater, which has attracted extensive attention of researchers. In this paper, the common microorganism, the mechanism of biomineralization, and the development bottleneck of biomineralization are respectively introduced, and then the enhancement of biomineralization is prospected from the aspects of microbial community regulation and solution parameters, to provide new ideas and technologies for the treatment of uranium-containing wastewater in the future.

Abstract:As a natural traditional medicine, Chinese herbal medicine is widely used in clinical medicine and daily health care because of its characteristics of pure nature, no drug residue and resistance, and little toxic and side effects. In the process of microbial fermentation of Chinese herbal medicine, the cellulose and lignin other substances in the cell-wall are degraded by enzymes produced by microorganisms, and the active components are released; The active components of Chinese herbal medicine are enzymolyzed into substances with small molecular, which could enhance the efficacy and be conducive to digestion and absorption of the body. After fermentation, some Chinese herbal medicines could reduce the toxicity and side effects and even produce new active substances. Meanwhile, some ingredients in Chinese herbs can promote the growth and reproduction of microorganisms. It can be seen that Chinese herbal medicine and microorganism have synergistic effect and complement each other. In this paper, the advantages, common microorganisms, application status, existing problems and key factors of fermentation of Chinese herbal medicine were reviewed, and the application prospect of fermentation of Chinese herbal medicine was prospected. It is believed that with the maturity of fermentation technology and the modern development of Chinese herbal medicine, the microbial fermentation of Chinese herbal medicine will have a broader development potential and application value in the future.

Abstract:In nature some anaerobic cellulolytic bacteria can produce cellobiose phosphorylase (CBP) and cellodextrin phosphorylase (CDP) in order to phosphorolyze cellobiose and cellodextrins, respectively. Both CBPs and CDPs belong to glycoside hydrolase family 94 (GH94), which have a high specificity for β-1,4-linked glycosidic bonds. At present, the properties and catalytic mechanism of CBPs and CDPs from different strains of bacteria have been extensively studied, and analysis of the protein crystal structures have revealed the structure basis of the two phosphorylases for catalyzing different substrates regarding their degree of polymerization. Because of the unique phosphorolytic reactions and reverse synthetic reactions CBPs and CDPs can catalyze, there have been many reports showing their applications which mainly include three aspects: construction of engineered yeasts that directly use cellodextrins, construction of enzymatic conversion pathway of cellulose to starch, and enzymatic synthesis of special sugars. Due to the rising interest in CBPs and CDPs, here we have reviewed the related studies and provided some perspectives about the future research areas.

Abstract:Ideological and political education is an important form of carrying out the fundamental task of “educating people with moral cultivation” in colleges and universities. In the fight against the COVID-19 epidemic, the Chinese nation forged a great spirit of fighting the epidemic by pulling together in times of difficulty and helping each other. This provides the most vivid element for ideological and political education. In this article, we combed and summarized the spirit of fighting the COVID-19 epidemic, and condensed its connotation into five contents. This paper took the nucleic acid detection of the novel coronavirus, the anti-epidemic spirit contained in vaccine development and its mutation as the carrier of thinking and government, selected the corresponding theoretical content in the genetic engineering course, and carried out the ideological and political teaching design and practical research of the Genetic Engineering course focusing on the anti-epidemic spirit. This paper evaluated the teaching effect by using questionnaire method and in-depth interview method. The purpose of this study is to guide students to understand the spirit of fighting the COVID-19 epidemic contained in the course content, while learning professional theoretical knowledge, internalize it into value pursuit, and imperceptibly improve students’ ideological awareness and moral cultivation. Meanwhile, it can provide reference for the ideological and political education of other biological majors.

Abstract:The core of “Double First Class” construction is to cultivate first-class talents, and courses are the core element of talent training. The construction of application-oriented demonstration courses is an important measure for local colleges and universities to cultivate applied talents, and its construction level directly affects the quality of personnel training. This article takes the “Clinical Microbiology Testing” course of Chengdu Medical College as an example, and introduces the reform and practice of the course around the course objectives, course content, teaching methods, and course assessment. These reforms pay more attention to the cultivation of professional knowledge, practical ability, innovation ability, and humanistic literacy in teaching, highlighting the training goal of high-quality clinical microbiological testing applied talents. Through years of reform and development, this course has formed a distinctive medical curriculum system, which can provide a reference for the construction of application-oriented demonstration courses in local medical colleges.

Abstract:Microorganisms are largely associated with food production, processing, storage, transportation and safety inspection and control. Microbiology is an important course that required by majors of Food Science and Engineering in most universities in China. We tried to reform teaching of Microbiology courses by adjusting the contents, strategies and performing a research-oriented teaching based on the training program of the Food Science and Engineering majors and the career development of graduated students in our college, in order to construct a rational teaching model of the course for those majors.