Abstract:[Background] PM2.5 has many toxic effects that seriously damage organisms with long-term exposure. However, few studies have found a simple method to measure its microbial activity, although microorganisms are the important biological components of PM2.5. [Objective] Few developed a fluorescein diacetate hydrolysis method to test microbial activity in atmospheric PM2.5 through a large number of experiments and simulations. [Methods] We optimized and determined main testing parameters. Samples were collected by using an OMNI FTTM Ambient Air Sampler with a flow rate of 5 L/min for 40 min. The concentration of fluorescein diacetate was 200 μg/ml, and acetone was added to stop the reaction after 1.5 hours in dark environment. Microbial activity in atmospheric PM2.5 was measured after 15 min. [Results] Microbial activity in outdoor and indoor PM2.5 in July 2017 was with the average of 0.873 ng/m3 and 1.110 ng/m3 sodium fluorescein. [Conclusion] This paper established an effective and accurate method to measured microbial activity in atmospheric PM2.5.

Abstract:[Background] Marine cage culture is a high-density and high feeding artificial breeding method. Sulfide pollution in marine cage culture environment seriously restricts the economic benefits and sustainable development of aquaculture. [Objective] The identification and analysis of the oxidation characteristics of sulfur-oxidizing bacterium B1-1 from the sediment of marine cage culture area, is to provide theoretical basis for sulfide pollution control of sediment in the marine cage culture area. [Methods] The species of strain B1-1 were identified by a variety of methods including Gram staining, plate colony morphologic observation, morphological characteristics research, 16S rRNA gene sequence analysis and the molecular phylogenetic tree construction. The optimal culture conditions (pH, temperature, substrate concentration, additional carbon and nitrogen source, and metal ion) for the oxygenation of strain B1-1 were determined. [Results] Strain B1-1 was Gram-negative, short rod and identified as Halothiobacillus hydrothermalis (Genbank accession number: KU362926). The optimal culture conditions for strain B1-1 in the shaking flasks were pH 8.0, 30 °C, and substrate concentration 5.0 g/L. The additional carbon source did not change the oxidation ability of strain B1-1. With the additional ammonium salt, such as ammonium sulfate and ammonium oxalate, the delay period could be shortened to 12 h. Besides, the addition of Mg2+ could significantly improve oxidation ability of strain B1-1, the oxidation rate could reach 100%. [Conclusion] Based on the high haloduric ability and the high ability of oxidation rate of the sodium thiosulfate, Halothiobacillus hydrothermalis B1-1 is of potential in the fields of bioremediation of polluted marine cage culture area.

Abstract:[Background] Salt Efflorescence is one of the major diseases caused by combined action of humidity and salt which threated the preservation of ancient wall paintings, but the fields like composition of fungi, its origin and salt tolerance have seldom been reported. [Objective] This study aimed at exploring the community difference of culturable fungi that isolated from brick murals with salt efflorescence disease and their surroundings in tombs, including Dunhuang Han dynasty tomb, Dunhuang Jin dynasty tomb, and Jiayuguan No. 5 tomb, meanwhile, it has purpose to explore the halotolerant ability of the isolated fungal strains in order to provide theoretical basis for better conservation of the brick-tomb wall paintings. [Methods] The surface morphology and crystal phase of samples were analyzed by scanning electron microscope combined with energy dispersive spectrometer (SEM-EDS) and X-ray diffraction (XRD). The culture-dependent method was employed to isolate fungal strains, and to combine with molecular techniques for identification, the community composition and structure characteristics of fungi were identified thereafter. Halotolerancy of all the isolated strains were determined by salt-gradient culture medium method. [Results] The dominant genera of the cultivated fungal genus were Penicillium, Aspergillus, Cladosporium, and the other groups including Fusarium and Chaetomium were rarely isolated. All of the salt efflorescence samples have some common species, such as A. versicolor, P. Aurantiogriseum and A. fumigatus. The community compositions of fungi isolated from the efflorescence samples were similar with their surrounding airborne samples. Most of the isolated strains could grow on culture medium containing 15% sodium chloride, a strain of P. chrysogenum do have their growth even in the 30% salt concentration. [Conclusion] Pencillium and Aspergillus were dominated in different ancient tombs, most of the fungal strains most of the strains have relatively strong capacity of salt tolerance.

Abstract:[Background] Lycoris aurea is a traditional Chinese medicinal herb plant commonly used to treat several diseases including Alzheimer’s disease and myasthenia gravis etc.which has important medicinal value. The plant grows vigorously in humus soil (loam), but its growth performance in yellow-brown (clay) soil is very poor. In the recent years, increasing attention has been given to the investigations on the interrelations between medicinal plants and their rhizospheric microorganisms because the microorganisms played important roles for the growth, development and accumulation of biological active components of medicinal plants. [Objective] To study the effects of rhizospheric fungi on growth of L. aurea, we analyzed fungal community structure and genetic diversities cultivated in two soils. [Methods] Soil microbial total DNA was extracted. The community structure and diversity were analyzed by using high-throughput sequencing etc. [Results] Total of 42 130 and 30 176 fungal ITS1 sequences were obtained from humus soil and yellow-brown soil, respectively. Rhizospheric fungi in humus soil and yellow-brown soil could be classified as follows: 6 Phyla, 25 classes, 61 orders, 123 families, 208 genera and 5 phyla, 20 classes, 48 orders, 85 families and 138 genera, respectively; among which, the most predominant Phyla both were Ascomycota (relative abundance > 70%). The dominant genera and their diversity indexes etc. were different between humus soil and yellow-brown soil. Ascomycota_unclassified, Fusarium, Zopfiella, Chaetomiaceae_unclassified, Ceratobasidium, Mortierella, etc. were predominant groups in humus soil. But there were significant differences in predominant groups of yellow-brown soil, including Sordariomycetes_unclassified, Fusarium, Acremonium, Rhizoctonia, Nectriaceae_unclassified, Hymenoscyphus etc. Among which, there was a significant positive correlation among Ascomycota_unclassified, Zopfiella, Ceratobasidium, Mortierella etc. predominant groups in humus soil and lycorine content in bulbs of L. aurea by using SPSS statistical software. [Conclusion] The genetic diversity of rhizospheric fungi in humus soil that is favorable for cultivation of Lycoris aurea were richer and higher as compared to those of yellow-brown soil. Its predominant fungal groups such as Ascomycota_unclassified, Zopfiella and Ceratobasidium etc. may be favorable for the growth and lycorine accumulation of Lycoris aurea.

Abstract:[Background] The exploration mission of deep space exploration in China in the next few years will be a “well blowout” development. The impact of microorganisms on space activities will attract more and more attention. However, there are few studies on phenotypic heterogeneity at home and abroad. [Objective] To investigate the effect of low-shear modeled microgravity (LSMMG) and low-shear normal gravity (LSNG) on the large intestine from the perspective of phenotypic heterogeneity Bacillus K12 caused by the impact. [Methods] The continuous culture of Escherichia coli K12 was simulated by a rotating cell culture system to simulate the environment of weightlessness. The phenotypic heterogeneity subtypes were selected from the morphology, color and morphology of the cells. The proliferation rate of different strains, antibiotic resistance, biofilm formation, environmental pressure resistance, and cytotoxicity were measured to assess the effects of low shear stress and simulated weightlessness on E. coli K12. [Results] Four strains with different phenotypic heterogeneity were isolated by continuous culture in rotating cell culture system. Two of them were from simulated weightlessness group (M1, Ma) and the other two were from normal gravity control group (N1, Na). Compared with the original strain (P), the four sub-populations showed significant changes in proliferation rate, biofilm formation, environmental pressure resistance and cytotoxicity, and their antibiotic resistance has no significant changes. [Conclusion] Low shear stress can induce the phenotypic heterogeneity of Escherichia coli in both simulated weightlessness environment and normal gravity environment with low shear stress. Compared with the original strain, the phenotypic heterogeneity strains are differentiated. There is no unifying direction, but we still need to be alert to the changing phenotypes that could be harmful to humans.

Abstract:[Background] Pseudomonas is well known to inhibit plant pathogenic microorganisms. However, other plant growth-promoting traits are less reported. [Objective] To characterize the plant growth-promoting traits of Pseudomonas sp. BP16, and reveal its growth promoting effect on wheat seedling and potato. [Methods] The strain was isolated through spread and streak plating on medium of inorganic-phosphorus. We identified the taxonomic position based on polyphasic taxonomy and characterized plant growth-promoting traits on selective media or colorimetry. Wheat and potato were plot planted with 3 treatments, the first adding fertilizer containing BP16, second adding null carrier without inoculant, and third not adding any of them. [Results] 16S rRNA gene sequence of BP16 showed the highest similarity to that of P. brassicacearum subsp. neoaurantiaca (99.38%), and yet there were some major differences in physiochemical characters between them. Beside nitrogen-fixation, BP16 also possessed strong capabilities of Ca-phosphate-solubilizing (water-soluble phosphorus in fermentation solution reached 67.15 μg/mL), and production of indole-3-acetic acid (8.93 mg/L), siderophore (2.46 of D/d) and 1-aminocyclopropane-1-carboxylate deaminase. Additionally, BP16 remarkably inhabited the potato late blight, flax fusarium wilt and sunflower sclerotinia pathogens with inhibitory rates of 76.19%, 32.00% and 22.22%, respectively. Compared with the controls, wheat inoculated by BP16 increased plant height, root length, chlorophyll content and biomass. The content of rhizospheric available phosphorus and nitrogen also increased by the range from 8.63% to 83.81%. BP16 significantly enhanced the potato yield. [Conclusion] BP16 represents a new subspecies of P. brassicacearum and has multiple plant growth promoting traits. It can be used as a plant growth promoting agent.

Abstract:[Background] Many microorganisms from plant rhizosphere soil have phosphate solubilizing ability, while phosphate solubilizing Leuconostoc mesenteroides have not been reported. [Objective] To isolate and identify efficient phosphate solubilizing bacteria from navel orange rhizosphere soil and investigate the application in phosphorus release. [Methods] Transparent circle assay was used to preliminarily screen the phosphate solubilizing bacteria. After secondary screening, soluble-P in the culture medium was determined by molybdate blue colorimetric method. Different parameters were determined to explore the phosphate solubilizing mechanism of one strain. The phosphate solubilizing mechanism of the strain was explored by measuring the content of low-molecular-weight organic acids in the fermentation broth, the enzyme activity of phosphatase and its pH value. [Results] Nine phosphate solubilizing strains out of 23 candidates were obtained after two step selection. Based on 16S rRNA gene sequence analysis and physiological and biochemical chanterization, a strain was obtained and named Leuconostoc mesenteroides G7. The optimal phosphate solubilizing conditions of the strain G7 were as follows: the initial pH was 6.0, the carbon source was glucose, and the nitrogen source was ammonium sulfate. G7 produced a mass of organic acids, and its acid phosphatase activity was higher than that of alkaline phosphatase. [Conclusion] Carbon source, nitrogen source and initial pH can influence the phosphate solubilizing ability of the strain G7. The phosphate solubilizing ability of G7 is mainly due to its large number of low-molecule organic acids produced during fermentation. The mechanism of phosphate solubilizing ability need to be researched thoroughly.

Abstract:[Background] Salinity is one of the most brutal environmental factors limiting the productivity of crop plants and soil quality. There is a need to develop simple and low cost biological methods for salinity stress management. [Objective] The fungi with phosphate solubilizing properties and salt-tolerance were selected from different soil samples and biological fertilizer in order to provide good application candidate as soil remediation. [Methods] The method of plate culture was used to screen the fungi with phosphate solubilizing ability. The classification status of the strains were determined preliminarily based on internal transcribed spacer (ITS) sequence analysis. The effects of NaCl on phosphate solubilizing ability of four isolates were measured. The correlation between phosphate solubilizing capability and pH value was analyzed. [Results] A total of 16 phosphate solubilizing fungi were obtained, and 4 strains of them increased the growth of rice germination significantly, including 1 strain (MF-1) identified as Trichoderma longibarchiatum and 3 strains (SD-2, XJ-7 and HLJ-3) identified as Talaromyces. The tolerance of salt depend on different strains. The salt-tolerance of SD-2 and XJ-7 were better than MF-1 and HLJ-3. XJ-7 was able to grow in media with 5% NaCl, the P solubilizing rate was 9.50%. HLJ-3 was able to grow in media with 1% NaCl, the P solubilizing rate was 6.93%. The P solubilizing rate of SD-2 and MF-1 were 9.07% and 3.73% without NaCl, respectively. The phosphate solubilizing capability and pH value had significant negative correlation in liquid medium for Talaromyces. [Conclusion] The present study found that the phosphate solubilizing ability of 4 strains were significantly different in different saline environments. These phosphate solubilizing fungi have great application prospect as biological fertilizer in saline soil.

Abstract:[Background] Proteus mirabilis is a Gram-negative and pleomorphic facultative anaerobe, and it is an opportunistic pathogen of zoonosis. [Objective] To confirm the pathogeny that causes goslings’ death at some geese farm in Tongliao, Inner Mongolia Autonomous Region, and characterize the virulence genes of the pathogenic bacteria. [Methods] The pathogenic bacteria were confirmed based on the pathogens screening and artificial challenge experiment, and identified according to 16S rRNA genes sequence and biochemical characteristics. Primers of 8 virulence genes (ureC, zapA, mrpA, ucaA, rsbA, pmfA, atfA, atfC) were designed according to the sequences of Proteus mirabilis reported on the GenBank and used to detect the virulence genes of the pathogenic bacteria by PCR amplification. [Results] The pathogenic bacteria isolated from infected gosling was proved to be the pathogeny to Proteus mirabilis. Analysis of 16S rRNA gene sequences of the AYQ-1 gave highest identity (99%) to P. mirabilis and named AYQ-1. This was further supported by phylogenetic tree and biochemical characteristics, AYQ-1 was identified as P. mirabilis. AYQ-1 gave positive PCR results for 8 virulence genes. Intraperitoneal injection with AYQ-1 could lead to goslings’ death, with a value of the median lethal dose (LD50) of 1.51×107 CFU/mL. Antibiotics sensitivity test showed that among 19 antibiotics tested, AYQ-1 was sensitive to 19 antibiotics such as streptomycin, aztreonam and ofloxacin, but it was resistant to 15 antibiotics such as vancomycin, penicillin and achromycin. [Conclusion] The pathogen was identified to be Proteus mirabilis, and it’s virulence genotype are ureC(+), zapA(+), mrpA(+), ucaA(+), rsbA(+), pmfA(+), atfA(+), atfC(+).

Abstract:[Background] Recently, the medicinal value of calcified alcohols analogues (active vitamin D and its analogues) in the treatment of tumors therapy and immune regulation has gradually been discovered and examined. However, as the current method for chemical synthesis is complex and difficult, more efficient preparation method of calcified alcohols analogues becomes a hot research focus. [Objective] In order to bioconvert the substrates of calcified alcohols analogues using Pseudonocardia sp. and further improve the bioconversion rate. [Methods] Raw materials and intermediates commonly used in chemical synthesis were bioconverted with Pseudonocardia sp. to find appropriate substrates. The bioconversion conditions were optimized by single factor method and orthogonal test. [Results] Alfacalcidol (1α-(OH)VD3), eldecalcitol intermediate (AD-M07) and paricalcitol intermediate (PC-M07) were bioconveted into calcitriol (1α,25(OH)2VD3), eldecalcitol intermediate (AD-M08) and paricalcitol (PC). The optimal bioconversion conditions of the above three substrates (1α-(OH)VD3, AD-M07, PC-M07) were as follows: peptone 20.0 g/L, glucose 15.0 g/L, PMCD 0.5%, temperature 25 °C to 30 °C, inoculation quantity 5% to 10%, bioconversion time 72, 72, 96 h, substrates concentration 1.2, 0.6, 0.6 mg/ml, initial pH 6.0 to 8.0. Under the above conditions, the maximum bioconversion rate of the three products is 85%, 96%, 75% respectively. [Conclusion] By optimizing the bioconversion conditions, the bioconversion rate of the three products was markedly increased, which provides a good reference for more efficient preparation of calcified alcohols analogues by bioconversion.

Abstract:[Background] Dental caries is harmful to human health. Streptococcus mutans is recognized as the main cariogenic bacteria. In our previous studies, we found the Bacillus subtilis (Bacillus subtilis zh78) isolated from oral cavity could inhibit the growth of S. mutans. However, its bacteriostatic components were still ambiguous. [Objective] This study aimed to (1): determine the possible small molecular metabolite of B. subtilis zh78 that may inhibit the growth of S. mutans by untargeted metabolomics approach; (2) evaluate the prospect of B. subtilis zh78 in caries prevention and treatment. [Methods] Firstly, we used the cold methanol to extract the metabolites in the bacteria solutions from the B. subtilis zh78 growth at 0 hour, 7 hours, 12 hours and 5 days respectively. Oxford cup method was used to test the antibacterial activity of the extracted metabolites against S. mutans. Then, gas-chromatography-time of flight-mass spectrometry (GC-TOF-MS) was utilized to metabonomics detection. Lastly, we used principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA) and Pearson correlation analysis to process the data. [Results] The metabolites at 5 days of B. subtilis zh78 showed the most obvious inhibitory effect on S. mutans. 36 kinds of substances, such as xylitol, amino acids and organic acids produced by B. subtilis zh78 were significantly related to its inhibitory effect on S. mutans. [Conclusion] The findings suggested that the B. subtilis zh78 could produce certain kinds of metabolites (e.g. xylitol, amino acids and organic acids) which might exert the antibacterial effects on S. mutans. The B. subtilis zh78 displayed its potential in oral probiotic application and the related studies.

Abstract:[Background] Peste des petits ruminants (PPR) is an acute, severe and contagious infectious disease caused by peste des petits ruminants virus (PPRV), which is endangering the sheep/goat-farming in Asian and African countries. [Objective] The objective of this study is to express PPRV H protein prokaryotically and to prepare its polyclonal antibodies. [Methods] According to the sequence of PPRV Tibet strain deposited in GenBank, h gene was optimized based on the codon usage bias of E. coli and synthesized by using two-step PCR. Then, the sequencing confirmed h gene was inserted into prokaryotic expression vectors pET-28a, pET-30a and pET-32a, respectively. The constructed recombinant plasmids pET-28a(-30a and -32a)-H were then transformed into E. coli BL21(DE3) for expression under the induction of IPTG. The expressed H protein from E. coli BL21(pET-30a-H) were purified by cutting out the aimed band from the SDS-PAGE gel. Polyclonal antibodies were prepared by immunizing New Zealand white rabbits with the purified H protein. [Results] The recombinant H protein expressed by E. coli (pET-28a (-30a, -32a)-H), with a relative molecular mass of about 70, 68 and 86 kD, respectively, mainly existed in a form of inclusion body, of which the expression level reached the maximum at 7 h after induction. The polyclonal antibodies prepared by immunizing the rabbits with the purified H protein from E. coli BL21(pET-30a-H) showed specific reactivity with expressed recombinant H protein. The titer values of the serum ranged between 1:6 400 to 1:25 600. [Conclusion] PPRV H protein was successfully expressed in prokaryotic cells, and high titer anti-H protein polyclonal antibodies were obtained, which laid a foundation for further research on the function of H protein, and the fine linear B cell epitope mapping of PPRV H protein.

Abstract:[Background] In recent years, maize stalk rot occurs widely and seriously in most corn-growing areas in China. Fusarium stalk rot not only causes an important economic loss of corn, but also is a serious threat to human and animal health because of the toxins produced by Fusarium species. [Objective] Among the complicated pathogenic fungi of corn stalk rot, Fusarium graminearum is one of the major pathogens. The infection mechanism of F. graminearum still remains an urgent research topic. [Methods] The plasmid pCAMBIA1300 was taken as the backbone, and the plasmid pCAMBIA1300-CFP-Kan, expressing the cyan fluorescent protein, was constructed using the overlapping PCR. Then the CFP gene was transformed to the genome of F. graminearum by Agrobacterium-mediated genetic transformation technology. [Results] After PCR identification and fluorescence microscopy, 31 strains labeled with CFP were acquired. [Conclusion] The pathogenicity test results suggested that F. graminearum successfully colonized in corn tissue under laser confocal observation. These results lay a solid foundation for study of the colonization of Fusarium species.

Abstract:[Background] Epichloae endophyte-cool season grasses associations spread widely in China, there is genetic diversity in endophyte. [Objective] we collected plants from 8 cities of 6 provinces throughout China and hundreds of strains were obtained. NRPS5 genes of 21 Epichlo? spp. strains obtained from endophyte-grass associations were detected. Genetic diversity of NRPS5 genes in Epichlo? spp. was analyzed. [Methods] Fungal genomic DNA was extracted. NRPS5 genes were detected by specific DNA primers by PCR, and PCR products were then sequenced and analyzed. Phylogenetic tree based on maximum-parsimony of NRPS5 gene was constructed. [Results] NRPS5 genes may be distributed widely in Epichloae inhabited in the cool season grasses of eastern China. There was a small number of bases difference in same Epichlo? spp. or different Epichlo? spp. from same host except Roegneria spp., and there was a large number of bases difference of different host plants. There was no correlation between the locations of the host plant, the time of collection and the formation of stromata, and the differences in the NRPS5 gene fragment were mainly related to the host plants. These results indicated that NRPS5 fragment sequence is conservative, should locate in the function core of the NRPS proteins. [Conclusion] NRPS5 gene is relatively conserved, and could be an aiding method to evaluate genetic diversity of Epichlo? spp. endophytes.

Abstract:[Background] CFL1 is one of the ferric reductase genes in Candida albicans, and mediates the reduction of iron in the cell surface to maintain iron stability in the cell. [Objective] To study the sensitivity and mechanism of CFL1 to oxidative stress. [Methods] We analyzed the growth and the ability to kill macrophages under the oxidative stress condition by means of liquid culture and macrophages model. Dimethyl sulfoxide (DMSO) was added to verify if it released the oxidative stress. The quantitative real-time PCR was used to analyze the expression of oxidative stress response genes in cfl1Δ/Δ. We constructed the strain WT-CAT1-GFP and cfl1Δ/Δ-CAT1-GFP to test if the over-expression of catalase changed the sensitivity. [Results] The deletion of CFL1 caused the decrease of the ability to kill macrophages and the expression of oxidative stress response genes. Besides, it resulted in the down-expression of catalase. However, the over-expression of catalase in cfl1Δ/Δ could recover nearly the same ability of oxidative stress response as the wild type. [Conclusion] CFL1 regulates the oxidative stress response genes in the transcriptional levels.

Abstract:As a new type of pollutant, antibiotic resistance genes (ARGs) come from complicated sources and distribute widely in different habitats to pose a great potential risk to ecological environment and human health. Meanwhile, class 1 integron plays an important role in ARGs horizontal transfer among environmental bacteria and turns them into antibiotic resistant bacteria (ARB). The abundance of intI1 and ARGs in the environment shows a significant positive-correlation, therefore Int I might be used as a molecular marker to indicate the mechanism of ARGs transfer and transformation in the environment and reflect the impact of human activities. In this paper, we introduce the sources and distribution of ARGs and Int I in the environment, review the dissemination mechanisms of ARGs via Int I and related research methods, and predict the future research trends based on the current research progress.

Abstract:Horizontal gene transfer (HGT) is a common mechanism for the exchange of genetic information between bacterial species, which contributes to the diversification and adaptation of microorganisms. Mobile genetic elements (MGEs), the drivers of HGT, are segments of DNA that encode enzymes and other proteins that mediate the movement of DNA within genomes (intracellular mobility) or between bacterial cells (intercellular mobility). Genomic island is an important MGE in bacteria. Mobile genomic islands are able to integrate into the chromosome of the host, from which they get excised under favorable conditions and are then transferred to a new host via transformation, conjugation or transduction. Genomic islands have a variety of biological function, such as antibiotic resistance, pathogenicity, xenobiotic degradation and heavy metal resistance. Genomic islands are mediated by integrase and regulated by diverse transcription factors in the process of metastasis. In this review, we evaluate the progress in regulation, excision and horizontal transfer of genomic islands in bacteria.

Abstract:Basic helix-loop-helix (bHLH) proteins belonging to a superfamily of transcription factors, are widely distributed in eukaryotic organisms. Members of this protein family can form homodimers or heterodimers, and then bind to E-box motifs to uniquely affect the transcription of genes. The bHLH transcription factors are widely involved in developmental processes, including cellular proliferation and differentiation. Therefore, they often play a very important role in regulating growth, development, and differentiation in eukaryotes. Here, we review the regulation process and biological function of bHLHs in Aspergillus species including Aspergillus nidulans, Aspergillus fumigatus, and Aspergillus oryzae, to provide a theoretical reference for further study on the growth and development of Aspergillus and functions of bHLHs.

Abstract:Heavy metals pollution is one of the hot issues in food safety. The use of food grade lactic acid bacteria to adsorb heavy metals has become a new research area. In this review article, we introduce the sources and harms of mercury, cadmium, and lead pollutions in the environment and food. We also summarize the potential application and mechanisms of adsorbing heavy metals using lactic acid bacteria. This review provided a feasible way to develop efficient adsorbent for lactic acid bacteria adsorbing heavy metals.

Abstract:Bacterial biofilms (BF) are surface-attached communities of cells embedded in an extracellular polymeric matrix. The cells are composed of polymers produced by the microorganisms themselves. Biofilm is a cause of multidrug resistance. A simple, reliable, quick biofilm analysis method facilitates the effective prevention and treatment of infectious diseases. In recent years, numerous methods for analyzing biofilm based on various principles have been developed. In this review, common microbiological, physical, and chemical methods of biofilm analysis are summarized, with a focus on the application of microscopy methods. New technologies such as Raman spectroscopy, imaging mass spectroscopy, and matrix-assisted laser desorption ionization-time of flight analysis are being applied in biofilm research. Accordingly, this review highlights the advantages and limitations of several methods with a view to assisting scientists in determining the most appropriate and up-to-date methods for their continued research.

Abstract:Plant innate immunity mainly includes the recognition of conserved pathogen-(or microbial) associated molecular patterns (P/MAMPs) by pattern recognition receptors (PRRs), and the recognition of highly variable effectors by highly polymorphic resistance (R) proteins. There is a wide range of signal molecules exchange and recognition between plants and pathogens. Small molecule compounds affect the signal regulation in plants and their pathogens, which decided the outcome of the competition between them to a large extent. Illustrating these signaling molecules and exploring their interaction between plant and pathogen will help to reveal the mechanism of plant disease resistance and to explore new genes related to plant disease resistance. Reported studies have identified these signal molecules and their roles in the interaction between plants and pathogens. Our review summarizes the process of signal molecules and mechanisms between plant and pathogen interactions, the occurrence and signal transduction caused by PAMP-triggered immunity (PTI) and Effector-triggered immunity (ETI), and the downstream signal molecules and signal transduction. We also indicate future research needs.

Abstract:Microbiology Experiment, based on the Microbiology theory course, helps students converting theoretical knowledge into practical ability. The traditional teaching method adopts the indoctrination teaching mode, so students are in a passive learning state. In order to transform students from passive learning to active learning, Microbiology Experimental teaching is reformed. First, from the analysis of job requirement, students are clear about their learning objectives. Second, to improve the students’ learning initiative, a variety of heuristic teaching methods are being practiced. In addition, the opening of the Microbiology laboratory transforms students from the experiments’ participants into the experiments’ leaders. Microbiology Experimental teaching reform, not only mobilized the enthusiasm of students to learn, but also stimulated the creativity of students, and improved the students’ experimental skills.

Abstract:Enzyme Engineering is one of major courses of bioengineering and biotechnology major, and is the bond among these courses of Microbiology, Biochemistry and Molecular Biology, Cell Engineering and Genetic Engineering, Fermentation Engineering and Chemical Engineering, it has very strong theory and practicality. To improve the quality of undergraduate teaching, strengthen the autonomous learning ability of students, and adapt to the society that needs comprehensive talents, combined with the practical teaching inside and outside the classroom and the development of information technology under the background of “Internet+”, this paper performed practice and thinking of diversified teaching reform in Enzyme Engineering.

Abstract:[Background] Salmonella is currently one of most common food-borne pathogens worldwide. Every year, food poisoning caused by Salmonella ranks the first among all bacterial poisoning incidents. [Objective] A reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) method was developed to detect Salmonella. [Methods] A series of primers were designed according to the specific conservative invA gene of Salmonella, Real-time fluorescent RT-LAMP method was established to detect Salmonella by optimizing primer selection and reaction conditions. The specificity and sensitivity of the method were studied by using Salmonella and its artificial contaminated skim milk samples, and compared with the sensitivity of reverse transcription polymerase chain (RT-PCR) method. [Results] The RT-LAMP assay successfully detected invA gene of Salmonella within 30 minutes at 65 °C. Five strains of Salmonella were positive and the other 21 tested strains were negative. In the extracting nucleotide from artificial contaminated skim milk samples, the sensitivity was 60 CFU/g, which was 100-fold higher than that of RT-PCR. [Conclusion] The established real-time fluorescent RT-LAMP method can rapidly detect Salmonella on site.