Abstract:[Background] Tobacco bacterial wilt disease caused by Ralstonia solanacearum is a typical soil borne bacteriosis, which widely occurs in the tobacco farms in south of China. Biological control is an effective measure to alleviate the occurrence of the tobacco wilt disease; however, the antagonistic agents still lack. [Objective] To identify the R. solanacearum isolates in tobacco plantations of Yunnan province, and to screen its antagonistic bacteria for biocontrol of tobacco wilt disease. [Methods] R. solanacearum was isolated and identified from the infected tobacco tissues from the farms in Yunnan province by the plate dilution method. Antagonistic bacteria were isolated by the plate confrontation method and the antagonism against wilt disease was investigated under laboratory and field conditions. [Results] The R. solanacearum strain RS-22 was isolated from the infected tobacco plant stem. Koch’s postulates was employed to further confirm the causal agent of the wilt disease. The antagonistic microorganism screening led to the discoveries of 12 biocontrol bacteria. Among them, the strain Y4, a Bacillus amyloliquefaciens, showed the strongest antagonistic effect to RS-22. Pretreatment of the tobacco or tomato plants by root irrigation significantly enhanced their resistance to the bacterial wilt disease. Moreover, syringe injection of Y4 could significantly promote the survival rate of the RS-22 infected N. benthamiana plants. Field application of Y4 remarkably alleviated the wilt disease in the tobacco farms in Wenshan county of Yunnan province. [Conclusion] RS-22 has a broad spectrum pathogenicity. Y4 significantly suppressed the growth of RS-22 and has excellent biocontrol effect on the RS-22 infection. This study provides a useful tool for the biological control of tobacco wilt disease.

Abstract:[Background] Microorganisms play a vital role in the degradation process of marine lignin, but there are few reports about the lignin-degrading bacteria that originate from the marine environment. [Objective] To isolate potential lignin-degrading bacteria from sediments of Pelagic Ocean, and to provide strain resources for the conversion of renewable chemical substances of lignin. [Methods] Enrichment and purification of lignin-degrading bacteria in 50 sediment samples from the Pelagic Ocean by using the medium with alkaline lignin as the sole carbon source, and then screen for potential lignin-degrading bacteria by using the decolorizing medium. The taxonomic status of potential lignin-degrading bacteria preliminarily determined by 16S rRNA gene sequencing and sequence identity comparison. [Results] A total of 283 strains were isolated from 50 sediment samples, including 263 potential lignin-degrading strains, which belonged to 32 genera in five class (Alphapreobacteria, Gamaproteobacteria, Bacilli, Actinobacteria and Flavobacteriia). [Conclusion] The sediment environment in the Pelagic Ocean is rich in lignin-degrading bacteria, which provided new references for the development and utilization of marine biological resources.

Abstract:[Background] The high latitude permafrost area in the Greater Khingan Mountains is the most sensitive region to climate change in China, and soil microorganisms play an essential role in maintaining the structure and function of forest ecosystem in the cold region. [Objective] In order to explore the soil microbial community structure of different forest types and its relationship with environmental factors in permafrost region of Greater Khingan Mountains. [Methods] Illumina Miseq high-throughput sequencing technology was applied to analyze the composition and diversity of soil bacterial and fungal communities in three typical forests (Larix gmelinii, Pinus sylvestris var. mongolica and Betula platyphlla). [Results] A total of 2 786 bacterial OTUs (Operational taxonomic units, OTUs) were obtained from three forest types, belonging to 38 phyla and 531 genera, of which the dominant phyla were Proteobacteria (31.45%?40.32%), Acidobacteria (14.24%?40.16%) and Actinobacteria (7.13%?22.15%); 1 803 fungal OTUs belong to 8 phyla and 263 genera with dominant phyla being Basidiomycota (40.43%?62.75%) and Ascomycota (35.81%?53.68%). Principal coordinate analysis showed that the differences between groups of bacterial and fungal communities were much greater than those within groups. Mantel test showed that the bacterial community structure was significantly correlated with pH, total nitrogen (TN), total phosphorus (TP) and soil water content (SWC) (P<0.05), and the correlation coefficient of pH was the largest. The fungal community structure was significantly correlated with SWC, TN and TP (P<0.05), and TN had the highest correlation coefficient. The results of redundancy analysis showed that the relative abundance of Proteobacteria and Basidiomycota was significantly positively correlated with TP. SWC and TN had a very significant positive correlation with the relative abundance of Acidobacteria and Ascomycota, and pH was positively relative to the Actinobacteria (P<0.05). [Conclusion] There are significant differences in soil microbial community structure among different forest types. Clarifying their distribution and main environmental driving factors are the key to grasp the process of forest ecosystem in cold regions.

Abstract:[Background] The carbon sources required for the growth of Bdellovibrio-and-like organisms are mainly derived from the host, and the effects of various carbon sources in the environment remain to be explored. [Objective] The effects of different extracellular organic carbon sources on the predatory life of Halobacteriovorax vibrionivorans was investigated to provide a theoretical basis for subsequent research on the predation mechanism and microbiological control agent against pathogenic bacteria. [Methods] Vibrio alginolyticus was used as host strain, an absorbance-based assay with 96-well plates for cell lysis and double-layer plate method were applied to determine the effects of different carbohydrates, yeast extract and tryptone on the predatory growth of H. vibrionivorans Y22. Comparative experiments between nonviable heat-deactivated and viable hosts, artificial seawater and Tris-HCl (25 g/L NaCl) culture system, were adopted to explore possible growth mechanism of strain Y22, combined with genomic analysis of strain Y22 and its host strain. [Results] Strain Y22 had no phosphotransferase system and ABC transporters of sugars, and could not use extracellular carbohydrates as carbon sources; The host V. alginolyticus could utilize sucrose, maltose, mannitol for growth and produce acid, which lead to the decreased pH value of the artificial seawater co-culture system, thereby block the predation of strain Y22. Glucose could not only decrease the pH value of artificial seawater co-culture system, but also changed the cell characteristics of the host, thereby block the predation recognition process of strain Y22. The host could not grow with starch and α-lactose, and these carbon sources did not affect the predation of strain Y22. Strain Y22 contained protein, polypeptide and amino acid membrane transporter genes, which allowed it to utilize the host protein as carbon sources and nitrogen sources. Around 1?5 g/L external yeast extract and tryptone could inhibit the predation of strain Y22, and the predation-inhibiting effect was found to be dose dependent. When the concentration of yeast extract was over 4 g/L, and the concentration of tryptone was over 5 g/L, the predation phenomenon of strain Y22 was strongly inhibited and almost invisible. [Conclusion] Environmental carbohydrates will affect the metabolic activity of host bacteria, acidify the co-culture system, and change the cell characteristics of the host, which inhibit the predatory activity of H. vibrionivorans. H. vibrionivorans can absorb and utilize the environmental protein or peptide, by which its predatory growth will be inhibited. The results will provide further insights into the predation mechanism and antibacterial application of Halobacteriovorax.

Abstract:[Background] With the increase of resistant microorganisms and the enhancement of drug resistance, it has become a global concern to find new drugs against resistant microorganisms. Ginger essential oil is a pure natural plant essential oil, which is a preferred choice of natural antibacterial materials. [Objective] To analyze chemical components of ginger essential oil, study its antibacterial activity against common opportunistic pathogens, and illustrate its possible antibacterial mechanisms. [Methods] The chemical components of ginger essential oil were analyzed using gas chromatography/ mass spectrometry (GC/MS). The antibacterial activity of ginger essential oil was studied by Oxford cup method, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC), respectively. Its kinetic growth characteristics were recorded by dynamic growth curves. The effect of ginger essential oil on bacterial ultrastructure was observed by transmission electron microscopy (TEM). [Results] The main chemical components of ginger essential oil were terpenes, including zingiberene (22.014%), β-sesquiphellandrene (11.276%), α-farnesene (8.222%), α-curcumene (6.854%), zingerone (5.610%), gingerdione (5.192%), 6-shogaol (4.670%), sabinene (3.393%), and β-bisabolene (3.080%). The MIC and MBC of ginger essential oil were 2.3 μg/mL and 4.6 μg/mL for Bacillus subtilis, 9.2 μg/mL and 18.4 μg/mL for both Staphylococcus epidermis and Staphylococcus aureus, 18.4 μg/mL and 36.8 μg/mL for Klebsiella pneumoniae, respectively. The experimental results of dynamic growth curves showed that ginger essential oil could prolong the growth lag phase and inhibit the growth rate of the bacteria. Moreover, results of TEM observation showed that ginger essential oil could destroy the cellular membrane and cause the leakage of the intracellular macromolecules. [Conclusion] Ginger essential oil is rich in terpenoids and has moderate antibacterial activity, which could destroy the integrity of cellular membrane and cause cell damage and death. This paper is expected to provide new methods for the prevention and control of harmful microorganisms.

Abstract:[Background] Cyclic diadenosine monophosphate (c-di-AMP) is an important secondary messenger molecule produced primarily within Gram-positive bacteria and is involved in cell growth, survival, stress resistance and many other aspects of bacterial physiology; however, there are few studies on c-di-AMP in lactic acid bacteria currently. [Objective] The gene of c-di-AMP-synthesizing enzyme from Lactobacillus plantarum was cloned and efficiently heterologous expressed in Escherichia coli, and its biochemical activity in vitro was studied. [Methods] c-di-AMP in L. plantarum-YRA7 was detected by HLPC and ESI-MS using the cell extract. Then the c-di-AMP-synthesizing enzyme gene (lpDacA) was cloned from the genomic DNA of L. plantarum-YRA7 and the recombinant plasmid pET-28a-lpDacA was constructed. The recombination protein was successfully expressed in E. coli BL21(DE3), and purified by Ni-NTA affinity chromatography. Then enzymatic characteristics in vitro was studied. [Results] c-di-AMP was detected in L. plantarum-YRA7. The recombinant expression plasmid pET-28a-lpDacA was constructed and the purified recombinant protein was obtained. The biochemical activity study showed that the purified recombinant protein converted ATP into c-di-AMP in vitro. Its c-di-AMP-synthesizing activity was dependent on divalent metal ions and exhibited higher activity in the presence of Mg2+ at a basic pH. We also found that RHR motif is essential for the c-di-AMP-synthesizing activity and is the ATP binding site of lpDacA. [Conclusion] Cloning, expression and characterization of c-di-AMP-synthesizing enzyme from L. plantarum will laid a solid foundation for future exploration on the physiological role of c-di-AMP in L. plantarum.

Abstract:[Background] Endophytes associated with plant have a wide range of applications in various fields, such as promoting plant growth, antagonistic activity, biological nitrogen fixation and degradation of toxic compounds. [Objective] The purpose of this study is to isolate and identify endophytic bacteria associated with Origanum vulgare L. and to evaluate their biological control ability against the apple canker disease in Xinjiang Wild Fruit Forest. [Methods] Culture-dependent method and 16S rRNA gene sequencing were used to identify the isolated strains. Endophytic bacteria were screened by plate confrontation method for their ability against the pathogen of apple canker. [Results] In this study, a collection of 168 endophytic bacteria were isolated from Origanum vulgare L. and identi?ed based on their 16S rRNA gene sequences as 4 phyla, 5 classes, 8 orders, 12 families and 17 genera. The dominant genus was Bacillus. Additionally, the results of isolation of endophytic bacteria from Origanum vulgare L. showed that TSA medium (M1) produced the highest diversity of bacteria, followed by NA medium (M6) and then Histidine-Raffinose medium (M5). The diversity of culturable endophytic bacteria from Origanum vulgare L. was rich in Xinyuan Wild Fruit Forest. The distribution of endophytic bacteria in root was more plentiful compared to that in stem and leaf. Fifty-nine strains of isolated endophytic bacteria were screened by plate confrontation method for their antagonistic against apple canker. The results demonstrate that a number of endophytic bacteria which can effectively inhibit the growth of pathogenic fungi of apple canker. [Conclusion] The diversity of endophytic bacteria associated with Origanum vulgare L. in Xinjiang was rich. In this study, a number of endophytic bacteria which can effectively inhibit the growth of pathogenic fungi of apple canker were screened out. Therefore, the results of this study provide a more abundant and effective source of endophytic bacteria from Origanum vulgare L. for biological control of apple canker disease in Xinjiang Wild Fruit Forest.

Abstract:[Background] The digestion and utilization of feed by cultured animals are often closely related to intestinal microbiota. [Objective] The composition of intestinal bacterial community of red swamp crayfish (Procambarus clarkii) was studied, and protease producing bacteria was screened from the intestinal tract of red swamp crayfish. [Methods] The bacterial community diversity in crayfish intestinal tract was analyzed by sequencing the bacterial 16S rRNA gene V3?V4 region on Illumina MiSeq PE300 platform, and the protease producing bacteria were screened by casein plate method and identified by molecular biology methods. [Results] The most prevalent bacterial phyla were Proteobacteria, Tenericutes, Firmicutes and Bacteroidetes in crayfish intestinal tract, accounting for 98.53% in total. There were 7 prevalent genera of Citrobacter, Candidatus_ Bacilloplasma, Hafnia, Enterococcus, Bacteroides, unclassified_f_Clostridiaceae and Shewanella, accounting for 91.67% in total. The protease producing bacteria screened by casein plate method belonged to Hafnia, Citrobacter, Klebsiella and Bacillus. [Conclusion] The core groups of bacteria in red swamp crayfish intestinal tract played an important role in protein digestion and utilization.

Abstract:[Background] Diarrhea due to enterotoxigenic Escherichia coli (ETEC) is one of the most frequent diseases in piglets. Baicalin-aluminum has a good therapeutic effect on ETEC-induced intestinal injury in piglets, but the mechanism of action remains to be clarified. [Objective] Screening out the most stable internal reference genes in ETEC under the stress of baicalin-aluminum is the basis for studying the effect of baicalin-aluminum on the expression of ETEC target genes. [Methods] In this study, 12 internal reference genes 16S rRNA, mdh, recA, gapA, gyrA, gyrB, rpoA, rpoB, mdoG, dnaG, secA and fusA were determined at different concentrations (250, 500 and 1 000 μg/mL) baicalin-aluminum using qPCR technology. The expression level after different culture time (4.5 h and 6 h) under baicalin-aluminum stress. Four methods including comparative Ct value method, geNorm, BestKeeper and NormFinder software were used to evaluate the stability of the expression of 12 candidate internal reference genes. [Results] The results show that rpoA expression is moderately abundant and the most stable expression among multiple analysis methods. [Conclusion] It was determined that rpoA is the best internal reference gene for ETEC qPCR. This study laid the foundation for the subsequent use of qPCR to study the expression of target gene function after baicalin-aluminum stress ETEC.

Abstract:[Background] As a conditioned pathogen, Staphylococcus aureus plays an important role in clinical infection. Therefore, the effective prevention and treatment methods should be studied more. [Objective] To isolate and analyze the biological characteristics of staphylococcus aureus phage, and to provide theoretical reference for the alternative prevention and treatment of Staphylococcus aureus. [Methods] A phage was isolated from sewage using pathogenic Staphylococcus aureus D085 as host and called vB_SauS_SAP3. The phage was obtained by PEG8000 concentration and cesium chloride density gradient centrifugation. It was stained with uranium acetate and observed via transmission electron microscopy. The phage host spectrum, optimal multiplicity of infection (MOI), one-step growth curve, temperature sensitivity, pH sensitivity and the effects of organic reagents on the activity of phage were determined. The phage’s genome was obtained by the equilibrium phenol method and illumina sequencing technology for genome sequencing analyzed. [Results] via transmission electron microscopy, phage vB_SauS_SAP3 has a head with diameter of 60±5 nm and a tail with length of 170±5 nm. It was also able to lyse five strains of Staphylococcus aureus and one strain of Staphylococcus chromogenes. The optimal multiplicity of infection was 0.1. One step growth curve showed that the latent period and the burst period was 20 min and 60 min. The burst size was about 210 PFU per infected cell. The phage vB_SauS_SAP3 was resistanted to temperatures below 45 °C and sharply inactivated beyond 45 °C. It can maintain stable activity in neutral pH and has a certain resistance in alkaline environment, but acid environment will make it sharply inactivated. The phage vB_SauS_SAP3 were completely inactivated when treatment with chloroform and isoamyl alcohol. The size of phage vB_SauS_SAP3 genome was 41 950 base pairs (bp) and ecoding 65 ORFs by predicted. The genome include GC content was 35.42%. Phylogenic analysis indicated that the phage vB_SauS_SAP3 was a member of siphoviridae and a new staphylococcus aureus phage. [Conclusion] The phage vB_SauS_SAP3 has a narrow host spectrum and can withstand certain temperature and alkaline environment, which was a new Staphylococcus aureus phage. The study of vB_SauS_SAP3 can provide theoretical materials for the study of Staphylococcus aureus phage.

Abstract:[Background] In recent years, pig farms have focused on the prevention and control of porcine reproductive and respiratory syndrome, porcine circovirus, classical swine fever, porcine pseudorabies, swine streptococcus and haemophilus parasuis disease, but ignored the potential harm of extraintestinal pathogenic Escherichia coli (ExPEC) to pig health. It is of great significance to understand the epidemic characteristics of ExPEC. [Objective] To study the distribution and epidemic characteristics of serotypes, phylogeny groups and genotypes of 54 strains of ExPEC isolated from pigs. [Methods] The glass plate agglutination test and the test tube agglutination test were used to identify the O antigen serotype. The PCR technology detection system phylogeny groups identified related genes, 28 ExPEC-related virulence genes, and multi-site sequence typing-related genes. [Results] Of the tested bacteria, 52 strains were identified the O antigen serotype, of which 40 strains were O38 (74.1%), the dominant serotype, 8 strains were O127 (14.8%), and O93 and O11 were both 2 strains (3.7% each). Among the tested bacteria, 44 strains belong to group B2 (81.5%), which is the main phylogenetic group. Group D and group B1 each have 5 strains (9.3% each); The frequency of ompA, ibeA, fimH, traT, focD, papA, iroN, iutA, iucD, cvaC, tsh, kpsMTⅡ, iss, and ompT was more than 50% of 28 ExPEC-related virulence genes, the detection rates of ompA and ibeA were 100% and 96.3% respectively, which were highly prevalent virulence genes. cnf1 was not detected, but bmaE, malX and iha were more likely to be distributed in group D strains. The tested bacteria showed a total of 31 types of ST, including 5 strains of ST10 and ST648 (9.3% each), and 4 strains of ST410 and ST101 (7.4% each). [Conclusion] The prevalence of pig-derived ExPEC serotypes and phylogenetic groups in different regions and at different times have certain differences, showing a dynamic process. There is no report of O38 as the dominant serotype, and the highly pathogenic B2 and D strains have a trend of increasing gradually. The ST type is complex and diverse, presenting genetic diversity, and to some extent has the same genetic background as human and avian ExPEC.

Abstract:[Background] Salmonella is an important zoonotic pathogen, due to the continuous emergence of drug-resistant strains, research on new prevention methods is imminent. [Objective] In order to investigate the effect of ssrAB, hilA, hilD genes on the pathogenicity of Salmonella enteritidis and screen safe and reliable strains for Salmonella live attenuated vaccines or vectors. [Methods] Using suicide plasmid-mediated homologous recombination technology to construct the single (ΔssrAB, ΔhilA, ΔhilD), double (ΔssrABhilA, ΔssrABhilD, ΔhilAhilD) and triple (ΔssrABhilAhilD) gene deletion strains, then comparing the differences in biological characteristics between the above-mentioned deletion strains and the parent strain. [Results] The growth rate of the mutant strains was not significantly different from the parent strains (P>0.05). The biofilm formation ability of ΔhilD was the strongest, and the other gene deletion strains had no significant changes (P>0.05). The LD50 of ΔssrABhilAhilD and ΔssrABhilA were the highest, ΔssrAB, ΔhilA and ΔhilD were the second, and the degree of duodenal lesions in mice caused by the parent strain is significantly more serious than deleted strains. Among all the deleted strains, the adhesion of ΔssrABhilAhilD to HeLa cells was the lowest, while the colonization rate of ΔhilD in mice was the highest. Besides, the body’s ability to secrete IL-1, IL-18 and IFN-γ has no significant correlation with ssrAB, hilA and hilD genes of Salmonella (P>0.05). [Conclusion] Among the 7 gene deletion strains constructed in this study, ΔssrAB, ΔhilA, ΔhilD, ΔssrABhilA and ΔssrABhilAhilD had the characteristics of low pathogenicity, well growth rate, and they could effectively stimulate cytokine production, which had the potential to be Salmonella live attenuated vaccines or vectors.

Abstract:[Background] Microcystins (MCs), one of the main harmful substances produced by cyanobacterial bloom, are found in estuaries, lakes and coastal waters. [Objective] Under different concentrations of carbon, nitrogen and phosphorus sources, the paper analysed the ability of Novosphingobium sp. ERN07 to remove MCs so as to achieve rapid degradation of MCs. [Methods] The degradation characteristics were determined by orthogonal experiments and gene transcription analysis associated biodegradation with the expression of functional genes so as to understand the degradation mechanism. [Results] The dual nutrients composed of glucose and sodium nitrate had weaker inhibition of biodegradation than single glucose or sodium nitrate. Compared to those under standard MSM medium, the decelerated biodegradation with glucose or sodium nitrate (1 000 mg/L) or phosphorus source (500 mg/L) related to lower up-regulation in mlr gene expression, suggesting that divergent mlr gene expression was one of the reasons influencing various nutrient conditions on degradation. [Conclusion] Novosphingobium sp. ERN07 has a high degradation ability of MCs. Before the bloom, carbon and nitrogen sources were removed effectively so that it can be effectively used in MCs polluted water treatment.

Abstract:[Background] Gut microbiota and exercise both are closely related to human health, but the effect of high-intensity interval training on gut microbiota is still limited. [Objective] To explore the effect of high-intensity interval training on gut microbiota, moreover provide reference for the prevention and treatment of the whole people’s physical health and gut microbiota related diseases. [Methods] 68 volunteers were recruited for high-intensity interval training 3 times a week for 12 weeks, fresh feces were collected before and after exercise, and 16S rRNA gene high-throughput sequencing techniques were used to analyze the gut microbiota. [Results] After 12 weeks of high-intensity interval training the Shannon index of gut microbiota increased significantly (P≤0.001); PCoA analysis showed that there were significant differences; the level of pre-exercise genus Faecalibacterium, Unclassified-f-Enterobacteriaceae, Lactobacillus, Unclassified-f-Pasteurellaceae, Acinetobacter; the level of order Enterobacteriales, Pseudomonadales; the level of family Enterobacteriaceae, Lactobacillaceae, Moraxellaceae abundance was significantly higher than that after exercise; but after exercise, the level of genus Ruminococcaceae-UCG-014, Eubacterium-ruminantium-group, Lachnospiraceae-UCG-010, Tyzzerella-3, Unclassified-o-Bacteroidales; the level of family Unclassified-o-Bacteroidales abundance was significantly increased. [Conclusion] 12 weeks high-intensity interval training can effectively alter the gut microbiota, but the effect of regulation on male and female students is different. The abundance of gut microbiota and beneficial microbiota increased significantly.

Abstract:CRISPR-Cas systems that are widely presented in bacteria and archaea, as the only adaptive immune system found in prokaryotes so far, resist the invasion of viruses and plasmids. Since the 1980s, several basic aspects of CRISPR-Cas systems have gradually become clear, including acronym, classification, and evolutionary relationships. Last decade, class II CRISPR-Cas systems, whose effector complexes have a simple architecture, have been attractive for developing a new generation of genome editing technologies. In order to make such gene editing tools safer and more convenient in practical applications, it is equally important to discover new CRISPR-Cas systems while optimizing discovered CRISPR-Cas systems through breakthroughs in the basic research area. This article takes CasX discovered in 2017 as an example, to outline the basic properties for a new type or subtype of CRISPR-Cas system and accompanying research methods.

Abstract:Quorum sensing (QS) is one of the most important cell-cell communication mechanisms used by bacteria. DSF-family QS signals are present in a range of Gram-negative bacterial species, regulating bacterial virulence and adaptation. In this review, the structural diversity and conservation of DSF-family QS signals, their biosynthetic pathways and two regulatory mechanisms controlling DSF biosynthesis were firstly introduced. DSF-family signals are all long-chain unsaturated fatty acids, their biosynthetic precursors include carbohydrates and branched-chain amino acids; the major biosynthetic pathway include fatty acid elongation cycle and the key enzyme RpfF with both dehydratase and thioesterase activities; two regulatory mechanisms involving protein-protein interactions were identified to control DSF biosynthesis in Xanthomonas and Burkholderia, respectively. Then, the key in planta QS signal used by Xanthomonas campestris pv. campestris during its infection of Chinese cabbage was introduced. Finally, some key scientific questions in this research area were discussed and prospected.

Abstract:Reactive oxygen species (ROS) refers to a category of highly reactive substances formed by ground-state oxygen molecules acquiring electrons. ROS can be generated by aerobic respiration electron transport chain that helps maintain normal physiological activity of bacteria. Lots of exogenous ROS are generated and accumulated during cleaning and disinfection, medical treatment, etc. Excessive ROS would bring oxidative stress, lead to oxidative damage, and even affect activities of bacteria. In this review, we analyze the oxidative stress response induced by excessive ROS, the correlation between excessive ROS and the formation, recovery or repair of special non-spore status of bacteria, and even leading to their death, to provide reference for the innovation of effective control of spoilage and pathogenic bacteria.

Abstract:The genus Cantharellus is an important resource for edible and medicinal fungi, with high economic, medicinal and scientific value. It is worldwide distributed and with high species diversity. This paper reviews its taxonomy and phylogeny. In addition, we summarize recent progress, especially on its composition and pharmacochemical, ecological habit and artificial cultivation. Taxonomic flaws such as misidentification and invalid names appeared in previous literature are indicated. Potential and importance of species diversity in Asia and Africa are predicted, as well as further research directions.

Abstract:Large amount of gut microbiota (GM) in the human body participates in the body’s material metabolism and immune response reactions. Gut microbiota plays an important role in maintaining the steady state of the respiratory system, especially the lungs. Gut microbiota is closely related to the development of tuberculosis. After reviewing the literatures on the correlation of gut microbiota with tuberculosis, we discuss here the characteristics of gut microbiota after tuberculosis infection, analyze the mechanism of gut microbiota on the body’s immune response. Moreover, we also address the role of diet structure and microecological preparations in the treatment of tuberculosis to provide a theoretical basis for the effective prevention and treatment of tuberculosis.

Abstract:RNA-binding protein Hfq is an important post-transcription regulator of bacteria. Previous studies on Hfq mostly focused on the effects of this protein on small non-coding RNA (sRNA) and mRNA. The most typical function of Hfq is to promote the base pairing of sRNA with its target mRNA and mediate the regulation of RNA stability and translation after transcription. In addition, Hfq can interact directly or indirectly with a variety of proteins. However, recent studies have shown that in addition to RNA and proteins, Hfq can also interact with DNA and play a direct or indirect regulatory role in various DNA metabolism processes such as DNA compaction and DNA replication. Additional target and functional identification will further reinforce the importance of Hfq as a core regulator of multiple metabolic pathways in bacteria. It also indicates that the function of this protein is not limited to its role in RNA and protein metabolism. In this manuscript, the latest research progress of Hfq in the regulation of DNA metabolism in recent years is summarized and its prospect is prospected.

Abstract:With the growing concern about the role of intestinal microbes in human health and disease, the metabolism of intestinal microorganisms has become one of the research hotspots in recent years. Previous studies have shown that applying intestinal microbiome and metabolomics may have important value in the host physiology, disease pathology, and pharmaceutical pharmacology. This paper reviews the research progress on the combined application of intestinal microbial genomics and metabolomics analysis.

Abstract:Terpenoids are an important class of plant natural products that exhibit a broad range of biological activities. They have a wide range of applications in the food, pharmaceutical and chemical industries, which lead to a huge increase in market demand for them. It is therefore of great importance to develop alternative sources of these value-added products to supplement or even replace the scarce and precious plant resources. At present, the well-known unconventional yeast Yarrowia lipolytica is fast becoming a promising chassis for the production of biofuels and biochemicals. In recent years, metabolic engineering of Y. lipolytica has provided a platform for effective production of valuable terpenoids. This review reports and summarizes some of the most interesting and promising recent progress of heterologous microbial production of plant terpenoids in the engineered Y. lipolytica strains, by elucidating the host strains, key enzymes, metabolic pathways, engineering strategies and product titers/yields. In addition, key challenges and future perspectives in this field are discussed.

Abstract:Clostridioides difficile is a Gram-positive, toxin-producing obligate anaerobic bacterium, which is the main pathogen causing antibiotic-associated diarrhea. Spore is an important factor causing spread of C. difficile and infection recurrence. Sporulation and germination of C. difficile play an important role in the development of infection. In recent years, more and more specific mechanisms of C. difficile spore formation and germination have been elucidated. In this article, we reviewed the recent research progress on the molecular regulation mechanisms of C. difficile sporulation and germination to provide ideas for the development of effective treatments targeting spores.

Abstract:The cell wall is a characteristic structure of yeast cells that distinguishes them from mammalian cells. The structural composition, synthesis and regeneration of the yeast cell wall are closely related to self-reproduction and the response to environmental stress. At present, the mechanism of spore wall formation, regulation processes and the function of spore wall synthesis-associated genes remain elusive. This article briefly describes the process of spore wall formation in Saccharomyces cerevisiae. The spore wall consists of the mannan layer, glucan layer, chitosan layer and dityrosine layer. We summarize genes involved in synthesis of these layers. The purpose of this study is to provide a reference for new antifungal drug target research.

Abstract:Antimicrobial resistance and drug residues in animal-derived foods threaten the global public health. Therefore, it is urgent to develop new antimicrobial drugs with high antimicrobial activity. Antimicrobial peptides (AMPs) have attracted much attention due to their small molecular weight, broad-spectrum antimicrobial activity, and low induced resistance. However, natural antimicrobial peptides have some defects, such as low antimicrobial activity, hemolytic activity and cytotoxicity. With the continuous optimization of antibacterial peptides sequence and structure, a variety of safe and efficient new antibacterial drugs with significant antibacterial activity in vivo and in vitro have been developed. PMAP-36 is a high cationic antimicrobial peptide with typical amphiphilic α-helical structure isolated from porcine bone marrow. In this paper, we review the advance in sequence design and structural optimization of porcine antimicrobial peptide PMAP-36.

Abstract:As a selective form of autophagy, mitophagy has recently been considered as a research focus. It has been reported that mitophagy has a critical role in eliminating damaged or excessive mitochondria to maintain the cellular homeostasis. In recent years, accumulating studies have focused on mitophagy hijacked by pathogens in regulating innate immune signaling pathways to manipulate the course of infectious diseases. This article reviews the progress of mitophagy in the infectious diseases caused by virus, bacteria and fungi, aiming at providing a new reference for further strategies of prevention and treatment of infectious diseases.

Abstract:Single-cell raman spectroscopy (SCRS) is an emerging technology that reveals the intrinsic biochemical profiles of individual cells. SCRS is non-destructive, label-free, and independent of cultivation, thus it is deemed as a rapid and efficient technology with low cost. Based on the principles of raman spectroscopy, herein, we summarize research progress and the latest technical direction of this technology in pathogen identification and drug susceptibility test, and then discuss the application feasibility in a clinical laboratory to provide a new option for the detection, identification and antimicrobial susceptibility testing of pathogenic microorganisms in the future.

Abstract:Bacillus cereus is a Gram-positive bacillus, which widely exists in the natural environment and has strong resistance to adverse environment. It is a kind of foodborne conditional pathogen that affects both humans and animals. Bacillus cereus can produce a variety of toxins that determine its pathogenicity. Therefore, the establishment of a rapid and accurate method for the detection of Bacillus cereus is very important for the diagnosis and timely treatment of the disease. This paper comprehensively summarizes the methods of detecting bacteria and toxins of Bacillus cereus in recent years, mainly compares the principle, detection range, advantages and disadvantages of each method, and discusses the feasibility of the new method, with a view to scientific provide basis and ideas for detection and identification of Bacillus cereus.

Abstract:As a new teaching concept, ideological and political education in the courses has been widely respected in recent years. The key point is to integrate ideological and political education into the teaching of various courses and to advocate a new concept called “invisible education”. In this study, based on the current situation of ideological and political courses, we analyze the necessity of integrating ideological and political education into Food Microbiology, and focus on the ways to explore ideological and political elements. By combining knowledge points of teaching materials with ideological and political education, we achieve to consolidate professional knowledge, strengthen ideological and political education, cultivate students’ scientific spirit and humanistic spirit, and increase cultural self-confidence. In addition, as a core course of Food Science and Engineering, Food Microbiology requires the combination of theory and practice. This article summarizes the practical effects of the course, explores the entry point of the professional knowledge of ideological and political education in this course, and provides some reference for an effective teaching method in food specialty.

Abstract:As a rapidly developing front line subject and an experimental subject with strong continuity, Molecular Biology plays very important roles in constructing the knowledge system of postgraduate, cultivating their scientific research accomplishment, innovative thinking and engineering practical ability. In order to meet the demand of talent cultivation system of new engineering, based on the outcome-based education (OBE) concept, we integrated the teaching contents, changed the teaching methods and established an “interactive” teaching model through the use of problem-based learning (PBL) teaching method, flipping classroom, discussion and other teaching methods with the help of modern information teaching platform and learning groups as units. Finally, we used a diversified assessment system combining process assessment and final assessment to evaluate the learning acquisition of students. The results of survey filled by the postgraduate and follow-up survey of their scientific research achievements showed that this exploration has achieved the desired objectives and laid a foundation for the cultivation of research-oriented comprehensive innovative talents in the field of bioengineering under the engineering background.

Abstract:Technology for modern microbiology is a new obligatory course in the training program for master degree candidate in Microbiology. In this paper, the teaching reform of the course is introduced from the aspects of teaching content, teaching method, assessment method and teaching effect.

Abstract:“Curriculum ideological and political education” is a new mode of political education for college students. Its core idea is to integrate ideological and political education into the teaching of various courses. In the teaching of Fermentation Engineering, we strive to improve teachers’ ability of ideological and political education. We explore the integration of ideological and political elements into introduction class, course knowledge points, historical stories, social hot spots and experimental training, and strive to realize the unity of “imparting knowledge” and “educating students”.

Abstract:The major of Health Inspection and Quarantine is one of the strong applications, and it requires a higher level of capability of the health inspection and quarantine professionals to inspect microorganism and properly respond to new and unexpected public health events. Due to conflicts addressed in teaching procedure of microbiological inspection experiments and the feedback from companies, faculties decided to integrate the related microbiological inspection experiment courses, which separate into two independent experimental courses, to meet different requirements and prevent the reduplication and unsystematic problems of experiments. Besides, the teaching contents focus on the comprehensive, design, and innovative experiments, which guides students to build innovative entrepreneurship and graduation thesis design. Also, one of the important mindset we have built for the students is the awareness of biosecurity and specialized laboratory training is offered. In order to meet job requirements and teaching objectives, students are encouraged to do preparation and participate in different experiments. The teaching reform shows that it can improve students’ practical ability and innovation ability, and accumulate students’ interest in learning and scientific research.

Abstract:The teaching model reform of the professional basic course of engineering specialty is crucial for the engineering education professional accreditation and the cultivation of applied talents. Taking the engineering education professional accreditation as an opportunity, in view of the shortcomings of the traditional teaching method under the background of the Internet, the teaching model of integration of problem-based learning (PBL) and small private online course (SPOC) was proposed based on the theoretical and practical characteristics of Food Microbiology. The problem introduction of pre-class, the problem intervention of inter-class and the problem feedback of after-class of the PBL and SPOC integrated teaching model, and the practical results had been analyzed and discussed. It provides reference for the improving independent learning ability and team cooperation consciousness, and the development of engineering education professional accreditation and engineering professional basic courses teaching in application-oriented local undergraduate universities.