Abstract:[Background] Escherichia coli uses glutamic acid as a precursor to synthesize limited heme through the C5 pathway. [Objective] The purpose of this study was to investigate the effects of the regulation of intracellular glutamic acid metabolism and over-expression of glutamyl-tRNA reductase gene (hemA) on 5-aminolevulinic acid (ALA) and heme synthesis. [Methods] Through Red homologous recombination, mscS and aroG which are related to glutamate metabolism were knocked out, and the hemA expression vector was constructed and introduced into the gene-knockout strains. [Results] The single and double gene-knockout had no significant effect on cell growth, but the content of glutamic acid increased, whereas that of ALA decreased slightly. The heme content in single and double gene-knockout strains increased by 11.6% and 35.7% compared with that in the parental strain respectively. [Conclusion] The over-expression of hemA in the double gene-knockout strain caused the increase of heme to 47.603 μmol/L. Heme synthesis can be promoted by regulation of intracellular glutamate metabolic flow and over-expression of hemA which provides a new approach for heme enhancement through C5 pathway.

Abstract:[Background] The study of soil microbial ecology is very important for ecological investigation of pollution in mining areas and ecological restoration of mining areas. The influence of high-sulfur coal cover on underlying soil microbial community is still unclear. [Objective] The purpose of this study is to explore the influence of long-term high-sulfur coal cover on bacterial community composition and diversity of the underlying soil in coal mining areas. [Methods] Three types of soil samples (high-sulfur coal cover layer, soil beneath high-sulfur coal cover layer, soil as control) were collected from coal yard of a high-sulfur coal mine. The influence of high-sulfur coal cover on soil properties and soil bacterial community was studied by measuring soil physical and chemical properties and using high-throughput sequencing technology. [Results] Compared with the soil as control, in the soil beneath high-sulfur coal cover layer, the pH value decreased, but the contents of sulfate, organic matter, hydrolyzed nitrogen and available phosphorus increased. For the underlying soil bacterial community, the diversity index decreased and the composition changed obviously. At genus level, the relative abundance of Bacillus in the underlying soil was higher than that of the control. The regularities of relative abundances of Acidiphilium and Sulfobacillus in three sample groups were “high-sulfur coal cover layer>its underlying soil>soil as control”. The preponderance of sulfur-oxidizing bacteria in the condition of high-sulfur coal and its influence on the underlying soil could be confirmed. The co-occurrence network analysis showed that Acidiphilium and Sulfobacillus played an important role in the soil bacterial community of the area covered by high-sulfur coal, and had a great impact on other bacterial genera. [Conclusion] The high-sulfur coal cover and the predominance of sulfur-oxidizing bacteria in it have obvious influence on the physical and chemical properties and the bacterial community of the underlying soil. The research results are helpful to enhance the understanding of soil microbial ecology in mining areas, and provide theoretical basis for the ecological restoration of high-sulfur coal mining areas in microbiology.

Abstract:[Background] Soil microorganisms are very sensitive to the changes of the microenvironment where they live. Bird island, as a lakeside wetland, is sensitive to climate change. However, there are few studies on soil microorganisms at bird island in Qinghai lake. [Objective] In order to explore the changes of soil microbial community characteristics in the bird island of Qinghai lake after climate warming. [Methods] Open-top chamber simulation was used to understand the community structure and diversity changes of soil bacteria and fungi after temperature rise through high-throughput sequencing method. [Results] The increase in temperature did not change the dominant microbial flora of soil microorganisms in bird island of Qinghai lake. The dominant bacterial flora was Proteobacteria and Acidobacteria; the dominant fungi were Ascomycota. Temperature increase changed the soil microbial community structure, significantly increased the relative abundance of Bacteroidetes, Cyanobacteria, Patescibacteria and Cystobasidiomycetes, and significantly reduced the relative abundance of Leotiomycetes. The diversity index of the soil microbial community has changed. After the temperature rises, the ACE index and Chao1 index of the microorganisms decrease, and the Simpson index of bacteria and Shannon index of fungi decrease. [Conclusion] Soil microorganisms respond significantly to temperature rise, and the community structure and diversity of microorganisms have changed since temperature rise.

Abstract:[Background] Resistance gene is critical to molecular biology research, however, containing the massive size always restricts its usage like limiting the length of the target sequence inserted into the vector. [Objective] Exploring resistance gene similar function of RNA aptamer simple molecules to optimize capacity of the vector and enlarge the target gene expressing section. [Methods] The tRNA scaffold recombinant RNA expressing strategy was used to enrich ribonucleic acid aptamer of antibiotic in vivo. Screening and verifying resistance of the RNA aptamer of the aminoglycosides antibiotic neomycin B. [Results] The tRNA scaffold recombinant RNA expressing vector was constructed and successfully applied to select in vivo. The two RNA aptamers, A Site and Avirus, were proved that could resist neomycin B with 19 μg/mL on LB plate and 30 μg/mL in liquid culture. [Conclusion] RNA aptamer could bind with antibiotic, leading to being a new kind of resistance gene. This strategy is expected to optimize the resistance gene, reduce plasmid vector capacity, which provides a new method for molecular biology research.

Abstract:[Background] Chemical control pollution is becoming more and more serious, “3R” problems are becoming more and more common. Therefore, screening new biocontrol strains and studying their antibacterial substances have become a hot spot. [Objective] To screen a strain of Bacillus velezensis that has biocontrol function against phytopathogenic bacteria such as Cochlioboluss ativus, and excavate its gene clusters that regulate the synthesis of bacteriocins and RiPPs (antibacterial peptides synthesized by ribosome pathway). [Methods] Strains were screened by methods such as separation and screening, confrontation culture, etc., and strain identification was performed by whole cell fatty acid, Biolog analysis and molecular biology methods. The Illumina Novaseq 6000 platform was used to determine the whole genome sequence, and the potential bacteriocins, RiPPs gene clusters and potential mechanisms of action were explored through BAGEL4. [Results] strain RJW-5-5 had the best inhibitory effect on Cochlioboluss ativus, and the inhibition rate reached 78.4%. Strain RJW-5-5 was identified as Bacillus velezensis. [Conclusion] strain RJW-5-5 can inhibit various crop diseases, has a variety of lantibiotic, lasso peptide, bacteriocin and other antibacterial peptide gene clusters, with broad development prospects and application potential.

Abstract:[Background] Root-knot nematode (RKN) disease is one of main factors constraining tomato production under greenhouse conditions in China. The arbuscular mycorrhizal fungi (AMF) contribute to the control of RKN and the growth of plant. [Objective] The effects of different AMF and combined inoculation on antagonizing the infection and propagation of Meloidogyne incognita were evaluated in two tomato cultivates differing in nematode susceptibility. [Methods] The two cultivars, one of which was susceptible cultivar (Monte Carlo) and the other (Xianke 1) was relatively resistant to root-knot nematode infection, were inoculated respectively by Acaulospora mellea (Am) and Rhizophagus intraradices (Ri) and the mixture of the two AMF species Ri+Am in the sterilized soil before inoculating root-knot nematode, Meloidogyne incognita. The growth of plants and the suppression to nematode infection were investigated. Furthermore, the tomato “Monte Carlo” was inoculated with the mixture of AMF and transplanted in the continuous cropping field soil infested by RKN to evaluate the effects on the growth of tomato and the protective effects against RKN. [Results] The mycorrhizal efficiency of Monte Carlo to inhibit nematodes was greater significantly than that of Xianke 1. Different AMF treatments had different inhibition effects on nematodes. The cultivar of Monte Carlo inoculated by the mixture of two AMF species Ri+Am showed higher protective effects than any single AMF inoculation treatment, while Xianke 1 inoculated by Ri was higher than other treatments. The infection of nematode also greatly influenced AMF colonization, especially to the cultivar Xianke 1. But the AMF colonization of most treatments was still up to 70% in harvest time, except for the species of Am. The tomato “Monte Carlo” inoculated with the mixture of Ri+Am significantly reduced the number of galls and egg masses of RKN in the continuous cropping field soil containing Meloidogyne incognita, comparing to the controls. [Conclusion] The colonization of the mixture of AMF alleviated the infestation of the nematode disease of tomato better than single AMF colonization to a certain degree. The protective effects of susceptible cultivar inoculated with AMF against nematodes were greater than those of the resistant cultivar to nematode.

Abstract:[Background] Classical swine fever is caused by classical swine fever virus (CSFV), which is highly contagious and fatal to pigs. Co-infection of CSFV with other swine pathogens is present in clinical practice, such as, CSFV is co-infected with foot-and-mouth disease virus (FMDV) in pigs. [Objective] The effects of co-infection of CSFV and FMDV in porcine host cells on replication of FMDV were studied. [Methods] We constructed an in vitro model of co-infection of CSFV and FMDV. The PK-15 cells were first infected with CSFV and then infected with FMDV. The replication of FMDV in FMDV-infected cells and the cells with co-infection of CSFV and FMDV was analyzed by cytopathic effect, real-time quantification PCR (RT-qPCR), Western Blot and indirect immunofluorescence assay, respectively. The CSFV proteins that included the inhibitive function on FMDV replication was subsequently screened by RT-qPCR analysis. [Results] Co-infection of CSFV C strain and FMDV inhibited the replication of FMDV. Meanwhile, the inactivated CSFV also showed inhibitive activity on FMDV replication. A detailed screening identified that CSFV C protein include the function to suppress FMDV replication. [Conclusion] We found that CSFV C strain infection could inhibit FMDV infection, and the C protein of CSFV included a function to inhibit FMDV replication.

Abstract:[Background] Avian β-defensin 6, an antimicrobial peptide secreted by avian, plays an important role in the resistance to pathogen invasion and immune regulation. However, its conventional expression is inefficient and difficult to be applied in industrial production. [Objective] In order to establish a stable expression of AvBD6 cell line, and detect the antibacterial activity of AvBD6 expression products against drug-resistant E. coli, it can provide reference for the expression of other defensive hormones. [Methods] Observe the transfection efficiency of the constructed eukaryotic recombinant expression vector pLOV-eGFP-AvBD6 after transfection into 293T cells using an inverted microscope; Collect supernatant of 293T cells and infect DF-1 cells, and select stable expression strains by puromycin pressure; Use RT-PCR and Western Blot to detect the expression of the target gene at the transcription level and protein level; Use scanning electron microscopy to observe the antibacterial effect of the cell culture supernatant on drug-resistant E. coli and the damage to the bacteria. [Results] The recombinant expression vector pLOV-EGFP-AvBD6 was successfully constructed, and DF-1 cell lines expressing AvBD6 were screened out. The target gene was expressed at both transcription and protein levels. Cell culture supernatant not only significantly reduced the survival rate of Escherichia coli and Salmonella paratyphi, but low antimicrobial activity against Staphylococcus aureus. [Conclusion] DF-1 cell lines with stable expression of AvBD6 were successfully established. The expression products of DF-1 cells have significant antibacterial effects on drug- resistant E. coli, and have certain guiding significance for the expression and industrial application of defensins.

Abstract:[Background] Monascus is an important food and drug homologous fungus, whose secondary metabolites have many physiological functions. However, the bioactive components in Monascus are rarely reported. It is of great significance to trace the active substances in Monascus fermentation broth for understanding the material basis of Monascus efficacy. [Objective] To study the bioactive components and biological functions of secondary metabolites of Monascus ruber Mr-1. [Methods] The active components were separated and purified by silica gel column and Sephadex LH-20. The structures of the compounds were analyzed by NMR and HR-ESI-MS. The antioxidant, antibacterial and enzyme activities of the identified compounds were determined in vitro. [Results] Four active compounds were isolated from the secondary metabolites of Monascus ruber Mr-1, which were identified as three flavonoids, luteolin (1), hesperetin (2), glycoitin (3), and one terpenoid, ursolic acid (4). Compounds 1, 2 and 4 were isolated from Monascus for the first time. In the antioxidant test, compound 1 had strong scavenging ability to ABTS+, DPPH and OH?, with IC50 of 13.36, 8.74 and 32.75 μg/ml, respectively; in the antibacterial test, compound 4 showed moderate antibacterial activity against Staphylococcus aureus and Listeria monocytogenes, and the diameter of inhibition zone was 13.4 and 11.9 mm, respectively; in the α-glucosidase inhibitory activity test, compound 4 showed a strong inhibitory activity, with IC50 of 21.34 μg/ml. [Conclusion] Monascus ruber Mr-1 is a valuable microbial germplasm resource. Its metabolites contain diverse bioactive components and it has the potential to be developed into functional food materials.

Abstract:[Background] The entomogenous fungi were important resources from the nature, but few of them were found and utilized comparatively. [Objective] To identify four entomogenous fungi collected from the field, and to explore the inhibitory effect of their ethanol extracts on Hela cells. [Methods] Four entomogenous fungi were identified by morphological characteristics, rDNA ITS and β-tubulin sequence analysis. The inhibitory effect of ethanol extracts from mycelium (M-1, M-2, M-3, M-4) and ferment liquid (F-1, F-2, F-3, F-4) on Hela cell proliferation were analyzed by MTT assay. The inhibitory activity of the ethanol extract with the strongest inhibitory effect was detected by cell morphological observation and flow cytometry. [Results] After identification, strains IS and LS are Isaria catenianulata, strains HLS and HLS2 are Isaria farinose. The results of MTT showed that eight kinds of ethanol extracts inhibited the proliferation of Hela cells to some extent, and the order of inhibitory effect of ethanol extracts from mycelium and ferment liquid was Isaria farinosa HLS>Isaria catenianulata LS>Isaria farinosa HLS2>Isaria catenianulata IS, of which F-3 had the strongest inhibitory activity (P<0.001), and its IC50 value was 0.667 8 mg/mL after 24 hours of treatment, while the IC50 value of the other seven ethanol extracts were higher than 1 mg/mL. The cell morphological observation showed that the inhibitory effect of F-3 on Hela cell growth increased with the increase of the concentration when Hela cells were treated with F-3 for 24 h, however. F-3 has only slight toxic effect on BHK-21 cells; flow cytometry showed that F-3 could induce apoptosis of Hela cells, and the total apoptosis rate could reach 32.45% when the treatment concentration was 1.0 mg/mL. [Conclusion] The inhibitory effect of four entomogenous fungi on Hela cell proliferation is significantly different, which may be related to the geographical origin and host of four entomogenous fungi. F-3 ethanol extract from Isaria farinosa has no significant inhibitory effect on the proliferation and growth of BHK-21 cells, but has the strongest inhibitory effect on Hela cells proliferation and growth and has the effect of inducing tumor cells apoptosis, suggesting that it has the further research value.

Abstract:[Background] Acinetobacter baumannii is highly resistant to antibiotics. Gene knockout is an important way to study the virulence and antibiotic resistance of A. baumannii. Currently, most gene knockout methods rely on the use of an antibiotic selection marker and are not suited for multidrug resistant strains. [Objective] This study aims to establish a marker-less gene deletion method to knock out the genes of multidrug resistant A. baumannii for subsequent experiments. [Methods] We used a two-step screening method using homologous recombination and the resistance of pMo130-TelR to potassium tellurite to construct the type VI secretion system hcp gene deletion mutant of A. baumannii. Then we tested the growth ability, bacterial competition ability and serum resistance of the mutant strain. [Results] By constructing a tellurite-resistant suicide vector inserted with recombinant fragment, pMo130-TelR-(hcp up-down), we successfully knocked out the hcp gene in A. baumannii. There were no significant changes in the growth ability of mutants, in contrast, the bacterial competitive ability decreased and the serum resistance increased significantly. [Conclusion] The marker-less gene deletion method using pMo130-TelR is applicable for creating gene deletion mutants in A. baumannii. It will be very useful in multidrug resistant A. baumannii gene deletion and will have profound significance for A. baumannii research such as the antibiotic-resistance mechanism.

Abstract:[Background] The antitumor mechanism of ω-3 polyunsaturated fatty acids represented by DHA and EPA has not been fully investigated. [Objective] To explore the relationship among ω-3 polyunsaturated fatty acids, Fusobacterium nucleatum and colorectal cancer. [Methods] After the suppressive effect of ω-3 polyunsaturated fatty acids (DHA, EPA, ALA) on human colon cancer cell line, Caco-2, and normal colon epithelium cell line, NCM460, was assayed, we investigated the impact of these ω-3 polyunsaturated fatty acids on F. nucleatum, including growth, adhesive ability to Caco-2 cells, and the expression of virulence genes such as Fap2, FadA and RadD. [Results] After treated with 30 μg/ml DHA, EPA or ALA respectively, the growth of Caco-2 cells were suppressed 9.09%, 4.95% and 7.52% correspondingly, meanwhile the growth of NCM460 cells were suppressed 31.15%, 25.48%, 29.11%, and only dose-dependent effect was identified. After treated with 30 μg/ml DHA, EPA and ALA for 12 hours, the adhesive ability of F. nucleatum to Caco-2 cells was inhibited by 81.04% (P=0), 93.63% (P=0) and 68.63% (P=0) respectively, which was consistent with the transcriptive level assay results of FadA, Fap2 in F. nucleatum. The expression of Fap2 was considerably suppressed by 10.22% (P=0.027) after 30 μg/mL DHA treatment; FadA, Fap2 were markedly suppressed by 23.49% (P=0) and 15.09% (P=0.003) by 30 μg/mL EPA; and for 30 μg/mL ALA treatment, FadA was significantly suppressed by 26.75% (P=0.012). [Conclusion] Based on our above results and previous reports that DHA, EPA and ALA only inhibited the growth of F. nucleatum temporally, we proposed that ω-3 polyunsaturated fatty acids i-e EPA and DHA significantly attenuated the adhesive ability of F. nucleatum to host cells via suppressing the expression of adhesion-related genes such as FadA, Fap2, which made major contribution to their antitumor activity, rather than inhibiting the growth of tumor cells and F. nucleatum directly. The effects and mechanisms of ω-3 polyunsaturated fatty acids i-e DHA and EPA on gut bacterium i-e F. nucleatum that play important roles in the initiation and progression of colorectal tumors deserve further research.

Abstract:Halophilic archaea is a kind of heterotrophic prokaryotes living in extremely high salinity environment. The extracellular enzymes secreted by these microorganisms can maintain enzymatic activity under the high salt condition, and play an important role in the leather industry, the treatment of high salt organic wastewater and pickle processing. In this paper, the sources and basic enzymatic properties of several common extracellular enzymes excreted by halophilic archaea such as extracellular protease, amylase and esterase are reviewed, to provide a reference for better exploitation and utilization of extracellular enzyme resources of halophilic archaea.

Abstract:Brucella is a Gram-negative, intracellular parasitic bacterium that can cause zoonosis- brucellosis. The pathogenic mechanism of Brucella is complex. Brucella can evade or inhibit the attack of host immune system and exert its pathogenic effect on the body by expressing a variety of virulence factors, so as to achieve its long-term survival in the host. Therefore, brucellosis is easy to transform into chronic infection. This paper reviews the research progress of a variety of virulence factors of brucellosis, in order to further understand the pathogenic mechanism of brucellosis and provide reference for the prevention and treatment of brucellosis.

Abstract:Fecal indicator bacteria (FIB) such as Escherichia coli, Enterococcus and thermotolerant Escherichia coli are indicator microorganisms used to indicate the degree of pollution in water bodies, but recent studies have shown that beaches have gradually become an important repository of FIB. Microbial source tracking technology are widely used to trace the source of FIB pollution on beaches, but the survival mechanism of FIB after entering the beach is unclear. Therefore, the influencing factors on survival of FIB on the beach are still the current research focus. This article reviews the sources of FIB in coastal and beach ecosystems, and analyzes influencing factors such as non-biological factors, biological factors, and interstitial flow that affect the survival of FIB. In addition, suggestions are provided addressing the potential risks of FIB to human health in the beach environment.

Abstract:Bacillus subtilis as a Gram-positive bacterium, which has clear genetic background and mature gene editing, and it was also considered as the important host of industrial enzymes. With the development of multi-omics sequencing technologies including transcriptome, proteome and metabolome, the rational design could simplify the Bacillus subtilis genome, reduce redundant regulatory and metabolic networks. It makes Bacillus subtilis more streamlined and easily to control. Furthermore, Bacillus subtilis as a heterologous enzyme expression host has been emerged the potential applications. This article briefly reviewed the advance in the effect Bacillus subtilis genome reduction, summarized the essential genes and the methods to identify them in Bacillus subtilis, highlighted the research progress and deletion strategies of Bacillus subtilis to enhance heterologous enzymes by deleting the genome, and demonstrated the important role of genome reduction in the construction of heterologous enzyme expression on the cellular chassis.

Abstract:Acinetobacter baumannii is Gram-negative non-fermentative pathogenic bacteria, which exists widely in the hospital environment and has become one of the important pathogens of hospital-acquired infection. Due to the widespread use of antibacterial drugs, the infections and outbreaks caused by multi-drug resistant Acinetobacter baumannii have brought great challenges. Recent research indicated that type VI secretion system (T6SS) might be related to the pathogenicity of bacteria. In this review, we summarized the research progress of T6SS and T6SS-related proteins (haemolysin-regulated protein, Hcp), which provided the basis for further investigation about pathogenesis of Acinetobacter baumannii.

Abstract:Hyaluronidases, a type of glycosidases, degrade hyaluronan and some glycosaminoglycans. These enzymes have a wide range of promising applications in the medical treatment, cosmetology, preparation of oligo-glycosaminoglycans, and so on. Many studies show that oligo-glycosaminoglycans have a lower molecular weight but a higher biological immune activity than glycosaminoglycans. In view of these important functions and applications of hyaluronidases, this review provides useful information to researchers for further theoretical studies and utilization of these enzymes. This review mainly introduces the definitions of hyaluronan and hyaluronidase, as well as the advances of classification, structures, catalytic mechanisms, enzymatic assay methods, recombinant expression, biochemical properties, and applications of hyaluronidases. This review also indicates future research directions of hyaluronidases.

Abstract:Nuclear localization signal-mediated protein entry into the nucleus is an important part of information exchange between the nucleus and the nucleus in the intracellular signal transmission network. Most viral proteins enter the nucleus in premise of being recognized by nuclear transport receptors and bound to the nuclear localization signals carried by viral proteins. The mechanism of important protein transport into the nucleus plays a vital role in the process of viral infection, and is of great significance for virus replication and virulence. The research on this mechanism is conducive to the discovery of new antiviral targets. This paper summarized the classification information of nuclear localization signals so as to conduct an analysis on comparisons of different nuclear transport receptors and their mediated entry mechanisms, and to sketch out the discovery of viral protein and its nuclear localization signal in the mechanism of viral infection.

Abstract:Lactic acid bacteria are the general name for Gram-positive bacteria that can ferment sugars and produce large amounts of organic acids. They have a long history of application in fermented foods. Lactic acid bacteria are generally considered to be safe strains. The genetic engineering operations of these microorganisms have broad application prospects in food and medicine. Expression vectors are one of the commonly used tools in genetic engineering. Most lactic acid bacteria expression vectors usually use antibiotic resistance genes as selection markers. However, resistance genes have potential metastasis, so food-grade expression vectors need to be developed. Food-grade expression vectors do not contain antibiotic resistance genes and only contain DNA from homologous hosts or generally considered safe organisms. This review introduces the composition of lactic acid bacteria food-grade expression vectors and their common hosts, and summarizes the application of lactic acid bacteria food-grade expression vectors.

Abstract:Proteus mirabilis is an important opportunistic pathogen causing nosocomial infection, and is widely distributed in the natural environment and intestines of humans and animals. Genomic islands (GIs) are 10?200 kb discrete DNA segments located on the chromosome of bacteria, which promote their host bacteria adapting to the complex and varied environment and are closely related with the adaptive evolution of bacteria. In recent years, several GIs associated with multidrug resistance (MDR) have been found in the genome of P. mirabilis, including Salmonella genomic island 1 and its related GIs, SXT/R391 integrative and conjugative elements and PmGRI1, indicating that GIs play important roles in the MDR formation and transmission in P. mirabilis. In this paper we reviews the research progress in the genetic characteristics, transmission mechanisms and prevalence of those GIs, which provides reference for further study of the GIs associated with MDR in P. mirabilis.

Abstract:Microbiome of female reproductive system are closely related to female reproductive health. Vaginal microbial flora changes are associated with a variety of vaginal diseases and may inflect the uterus through the cervix, inflammatory response in the uterus during pregnancy can lead to preterm birth (preterm birth, PTB). PTB is defined as a delivery that occurs at 28 weeks but less than 37 weeks of gestation, PTB infant mortality rate is very high and is faced with a variety of health-disease, in addition to clear the infection of pathogenic microorganism, PTB accompanied by microbiome imbalances in reproductive system, it is hoped that PTB can be prevented according to the dynamic changes of female reproductive system microbiome in the future. This review will focus on the relationship between the female reproductive system microbiome and reproductive health, especially with PTB.

Abstract:The type VI secretion system (T6SS) is a contractile secretion machinery with a needle-like structure, and capable of delivering effectors that can play a role in host colonization and niche establishment. In recent years, the presence of a functional T6SS in Campylobacter jejuni has been reported. However, the effect of T6SS to the virulence factors of C. jejuni were still unclear. This review provided the recent studies on T6SS of C. jejuni, including the structure components, prevalence, and function, which is to reveal the molecular mechanism for virulence factors of C. jejuni.

Abstract:Bacillus spp. contains a variety of antagonistic bacterias of plant pathogens, which can be widely used in the control of plant diseases. However, the use of biocontrol bacteria alone for biological control is often unable to achieve a better control effect due to the influence of environmental factors, and the control efficiency can be improved by combined use with low-dose fungicides. The research status, control effects and research methods of integrated control of plant diseases by the combination of biocontrol Bacillus and fungicides were reviewed in this paper. The combined use of Bacillus and fungicides can not only ensure the control effect, but also can greatly reduce the application of chemical pesticides.

Abstract:Butyrate-producing bacteria is a kind of bacteria which produce butyrate by fermenting carbohydrate, and its representative species is Clostridium butyricum. The main genus of butyrate-producing bacteria in the intestinal tract of animals and humans are Clostridium, Clostridium leptum, Roseburia, Eubacterium and Butyrivibrio. On the one hand, this paper introduces the species and characteristics of some butyrate-producing bacteria, effects of dietary fiber intake and intestinal probiotics on butyrate-producing bacteria. On the other hand, the physiological function of its main metabolite butyrate in vivo was discussed. In order to provide a theoretical basis for the application and product development of butyrate-producing bacteria.

Abstract:The composition of microorganisms is complex in the fermentation process of liquid fermented foods. The complex microbial fermentation system can affect the growth and metabolism of microorganisms, then change the microbial community structure and function, and ultimately affect the quality of liquid fermented foods. Lactic acid bacteria play an important role in the formation of flavor substances, improve nutritional value, and inhibit the growth of spoilage bacteria in food fermentation. This article mainly reviews microbial community structure and the interaction between lactic acid bacteria and other microorganisms in liquid fermented foods such as vinegar, soy sauce and beverage wine in recent years. To understand microbial community structure and the type of interaction between lactic acid bacteria and other microorganisms in the fermentation process of liquid fermented food, explore the function of lactic acid bacteria in the fermentation process and the interaction mechanism between lactic acid bacteria and other microorganisms.

Abstract:Norovirus is the main foodborne pathogen of human acute gastroenteritis. Due to its rapid mutation and lack of a robust cell culture system and small animal infection model, thus hinders our in-depth study of this pathogen. In recent years, the discovery of culturable murine norovirus, the establishment of human norovirus intestinal enteroids cell culture system, and the construction of reverse genetic operation system of norovirus have provided favorable tools for the systematic study of the pathogen, and deepen our understanding of its life cycle, replication mechanism, pathogenic mechanism, virus-host interaction, and so on. In this paper, we reviewed the progress of reverse genetics in norovirus research and discussed the application and development foreground of reverse genetics technology in norovirus molecular virology research and vaccine preparation, aiming to provide new strategies for virus prevention and exploring new drug targets against norovirus, and further promoting the food safety risk prevention and control in our country.

Abstract:Fermentation Engineering is a core course with strong practicality and applicability of Bioengineering. Based on outcome-based education (OBE) concept of Engineering Education Accreditation, reasonable and specific course objectives of Fermentation Engineering were formulated, focusing on training students’ engineering knowledge, problem analysis, engineering design and research ability. Aiming at the achievement of course objectives, the teaching content, methods, design and implementation of different content modules were integrated and optimized, and diversified assessment methods were adopted focusing on formative evaluation of the course. The evaluation model of course objectives achievement was constructed and a closed-loop course quality assurance system of design-implementation-assessment-evaluation-improvement was formed. The teaching reform effectively improved students’ ability to understand, analyze, design and study fermentation engineering problems, also enhanced students’ scientific interest and innovation ability.

Abstract:Online learning platforms such as MOOC are the result of education informatization, and the breakthrough in traditional teaching combined with MOOC is one of the hot topics of recent teaching reform. Microbiology Engineering course is a compulsory course for biotechnology and bioengineering majors in colleges. It is a strong applied and practical course. In order to deepen students? understanding of theoretical knowledge and cultivate students? scientific thinking, we have introduced an open teaching model based on MOOC in the Microbiological Engineering experiment course. The results showed that open teaching under the background of MOOC had a good effect in enhancing learning interest, training creative thinking, enhancing scientific research literacy, and cultivating teamwork ability of students.

Abstract:Ideological and political education is an important measure of the reform and innovation of the ideological and political courses in colleges and universities, which has gradually become the direction of the course reform because of its advantage of unity of moral and intellectual education. This study explored the effect of ideological and political education in Pathobiology and Medical Immunology for “5+3” integration of Traditional Chinese Medicine (TCM) program under the COVID-19 epidemic situation. The research subjects included two classes of “5+3” integration of TCM program in Grade 2018 in Chengdu University of TCM. We adopted traditional teaching mode in class 1 and teaching mode of ideological and political education in class 2. On the basis of traditional teaching mode, the ideological and political education materials were organically integrated into learning before, during and after the online lesson. At the end of the course, we conducted a survey about themes of patriotism, self-confidence in TCM, scientific literacy and mutual learning among civilizations to assess students’ understanding of the ideological and political elements between the two classes. At the same time, the students were also investigated for course satisfaction degree and the scores of ideological and political test, and the results were compared between the two classes. The score of ideological and political test and course satisfaction degree of class 2 were higher than class 1 (P<0.01), which indicated that the ideological and political education mode was better than traditional teaching methods under the COVID-19 epidemic situation. The ideological and political education mode was more effective in cultivating people with moral character while improving professional quality of medical students. Our study can provide a reference of ideological and political education for other medical programs, and promote the comprehensive advancement of ideological and political education in medical courses.

Abstract:CRISPR, a gene editing technology, has become a powerful molecular technology which has been increasingly applied in scientific research and clinical trials. In order to solve the problems of high complexity in principle, difficulties in operation, high time consumption and economic cost, we have constructed a virtual simulation teaching software of CRISPR gene editing technology that can be utilized in the experimental teaching. The system consists of two modules, which are principle demonstration and operation training. In the principle part, the structure of each molecule is presented by 3D technology, and the molecular mechanism of CRISPR-Cas9 is displayed in the form of animation. The practical operation part simulates the operation process of the whole experiment, and students can learn and operate repeatedly on the computer in the form of interaction. This interactive virtual experiment can stimulate students’ interest in learning, as well as significantly improving the quality of experimental teaching.

Abstract:The applicable microbial resource is abundant in Ili River valley. This paper explores the teaching reform of research-based experiments of Microbiology by combining with the local characteristic microbial resources. The concrete measure is to exploit and apply the experimental samples, to modify the contents and methods of experimental teaching. The survey analysis of the teaching effect shows it is beneficial for students to cultivate their innovating and scientific research ability.

Abstract:“Team-based learning” mode was applied in Medical Immunology course for Clinical Medicine Science Major. In theoretical teaching, the case-based, problem-based, role-exchange and seminar-based instruction were used, while the hierarchical-instructed learning were adopted in the practice teaching during experiment courses, elective experiment courses, and university student innovation project. In all the teaching processes, various teaching methods such as Mind Mapping, Wenjuanxing, and Growth Record Bag were employed comprehensively. Ideological and political education were transmitted through telling many curriculum politics cases along with medical knowledge, and diversified evaluation were implemented based on team-process-assessment. Through this mode, students’ autonomous learning ability, team cooperation ability, practical ability, innovation ability and humanistic quality have been cultivated. It was well established that the basement for educating high-quality, high-capability applied talents. The team-based learning mode accepted by most students can provide thinking and reference for the conduct of basic medical courses, other related courses and the cultivation of talents in universities.

Abstract:[Background] Brucella is an important intracellular bacterium to cause brucellosis in animals and humans. The key measure to prevent and control brucellosis is to choose high effective disinfectant to remove Brucella from the environment. [Objective] To evaluate the sterilization effect of common disinfectants on Brucella. [Methods] Nine common commercial disinfectants with high, medium and low concentrations were selected to study their sterilization effect on Brucella abortus, melitensis and suis. At the same time, according to the effective concentration of disinfectants, we determined the minimum inhibitory concentration (MIC) of each disinfectant. [Results] Except for phenol, the other eight disinfectants, including povidone iodine, decamethonium bromide, benzalkonium bromide, glutaraldehyde, compound quaternary ammonium salt, ethanol and two commercial disinfectants, could completely eliminate Brucella within 5 minutes. The bacterial survival rate of iodate acid preparation at low concentration (0.1%) was 0.000 039%?0.000 095%. For phenol, the bacterial survival rate was 0.000 144%?0.000 183% in 5 minutes and 0.000 138%?0.000 193% in 20 minutes at the recommended concentration of 0.5%. The bacterial survival rate of Brucella suis was 0.000 125% in 5 minutes and decreased to 0.000 038% in 20 minutes at the concentration of 1%. MIC results showed that the MIC of quaternary ammonium disinfectants ranged from 0.015 63% to 0.031 25%, and the MIC results of other disinfectants were basically consistent with the minimum recommended concentration of disinfectants. At the same time, it was found that different species of Brucella had different sensitivity to the same disinfectant. [Conclusion] This study provides reference for disinfectant usage scientifically and reasonably in practice.

Abstract:[Background] Salmonella is a pathogenic bacterium that can cause human and animal diseases, and is also one of the most important foodborne bacteria. Salmonella in soil causes food poisoning in humans through plants such as vegetables. However, due to the nature of the soil and interference from other microorganisms, how to quickly identify whether the soil is contaminated with salmonella remains a challenge. [Objective] To develop a real-time recombinase aided amplification (RT-RAA) method for rapid and sensitive detection of Salmonella in soil. [Methods] A pair of specific primers and a probe were designed targeting the sequence of invA gene in Salmonella, and a recombinant plasmid containing invA gene fragment was constructed to evaluate the sensitivity of RT-RAA method. The specificity of RT-RAA method was performed by amplification of template DNA from standard strains including Salmonella enteritidis, Escherichia coli, Shigella flexneri and Staphylococcus aureus. RT-RAA method was used to detect Salmonella in soil of tomato and ginger, and plate culture method were used to verify the results. [Results] RT-RAA method can be used to detect invA gene fragment in the recombinant plasmid at a minimum copy number of 10 per reaction within 20 min at 39 °C, without cross-reaction with Escherichia coli, Shigella flexneri and Staphylococcus aureus. RT-RAA detection of the DNA in the tested soil samples showed that the tomato soil was contaminated with Salmonella, while the ginger soil was not, which was consistent with the results of plate culture. [Conclusion] RT-RAA method has the characteristics of high sensitivity and specificity, and can be used for rapid detection of soil salmonella contamination.

Abstract:[Background] Viruses could be disseminated through asexual reproductive materials and severely affect the output and quality of strawberry. The production of virus-free seedling is one of the main methods to control strawberry viral diseases. Therefore, the efficient and sensitive detection of viruses is important for viral disease control. [Objective] To investigate the occurrence of eight important viruses commonly infect greenhouse strawberry in Beijing, the different strawberry plants collected from different districts were tested by enzyme-linked immunosorbent assay (ELISA). [Methods] We established a double-antibody sandwich ELISA (DAS-ELISA) method to detect eight viruses. Compared with the negative control, the positive control samples showed expected results in indirect ELISA and double-antibody sandwich ELISA (DAS-ELISA) analyses. Combined?with the symptom observation in the field, DAS-ELISA was used to detect viruses in the greenhouse strawberry samples. Virus infected samples were further verified by reverse transcription-polymerase chain reaction (RT-PCR) and sequence analysis. [Results] The results showed that only strawberry mild yellow edge virus (SMYEV) was detected in strawberry plants collected in Beijing. 8.1% of ‘Benihoppe’ and 2.7% of ‘Tianxiang’ cultivar plants tested could detect the infection by SMYEV, whereas there were no virus detected in other varieties. [Conclusion] This study presents important information and techniques for virus detection and strawberry viral disease management in Beijing area.

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