Abstract:[Background] Kangiella is gram-negative, obligate marine heterotrophic bacteria. The Kangiella genus forms deep branches within the class Proteobacteria in the phylogenetic analyses based on 16S rRNA gene sequences. The physiology and ecological role of this group of marine bacteria are still unknown. We assume that the extracellular serine proteases play an important role in the growth of Kangiella for recycling of organic nitrogen. [Objective] Analyzed physiological effects of different metal salts (Na salt, Mg salt, Ca salt, K salt) on the growth and the expression of alkaline serine protease genes of 4 Kangiella strains (K. aquimarina DSM 16071, K. geojedonensis YCS-5, K. koreensis DSM 16069 and K. profundi FT102). [Methods] The growth of 4 Kangiella strains in different versions of marine broth 2216E were observed. Using Folin method to test the extracellular protease activities with 2% casein as substrate. Three conserved alkaline serine protease coding sequences (asp1, asp2 and asp3) and phoP, phoQ genes in K. profundi FT102 were amplified by PCR and cloned. Real-time PCR method was used to evaluate the expression level of these genes in the 4?strains. [Results] Based on the growth curve of 4 Kangiella strains in different versions of 2216E, we found that Kangiella strains can’t grow in the absence of NaCl. However, except K. koreensis DSM 16069, the growth curves of other 3 Kangiella strains in different version of marine broth 2216E, in which no supplementation of either magnesium salt, or calcium salt, or potassium salt, were found similar. The extracellular protease activities of 4 strains were found different in logarithmic period, the maximum extracellular protease activity was 11.23 U/mL and lowest was 0.99 U/mL. Moreover, the results of Real time-PCR showed that the variety of the transcription level of 3 conserved genes (asp1, asp2, asp3) in K. aquimarina DSM 16071, K. geojedonensis YCS-5 and K. koreensis DSM 16069 was not obvious. But for K. koreensis DSM 16069, the transcriptional level of these 3 conserved alkaline serine protease coding genes was significantly upregulated, when either magnesium salt or calcium salt was omitted in the marine broth 2216E. [Conclusion] Na salt is necessary for the growth of Kangiella strains, Mg salt and Ca salt have different effects on the transcription of 3 serine protease coding genes asp1, asp2, asp3. The biomass, extracellular protease activity and the transcription level of 3 conserved serine protease genes and phoP, phoQ were significantly elevated in K. koreensis DSM 16069 when Mg salt was not supplemented in the marine broth 2216E.

Abstract:[Background] Ectoines have been applied in cosmetics, enzyme preparations and pharmaceutical industry due to their powerful stabilizing property of protecting enzyme, protein, nucleic acid and the whole cell against high temperature, freeze and dryness. Up to now, industrial-scale production of ectoines relies on bacterial milking process using moderately halophilic bacterium. Therefore, development of high-yield ectoine-producers and related fermentative technology has attracted considerable attention worldwide. [Objective] The objective of the present study was to isolate a moderately halophilic bacterium capable of synthesizing ectoines as main compatible solute, study the effects of osmotic shocks on synthesis and release of ectoines in this bacterium and explore the feasibility of producing ectoines by using bacterial milking process. [Methods] Moderately halophilic bacterium was isolated by spread-plate method and identified through analysis of its morphology, physicochemical properties and 16S rRNA gene sequence similarity. Ectoines were analyzed quantitatively and qualitatively by high performance liquid chromatography (HPLC) and mass spectrometry (MS), respectively. Ectoines were prepared by bacterial milking process. [Results] A moderately halophilic bacterium Y capable of synthesizing ectoines as main compatible solute was isolated from saltern sediment and identified as a member of the genus Halomonas according to its physiological properties and 16S rRNA gene sequence similarity. Halomonas sp. Y showed growth in lactate medium containing a wide range of NaCl concentrations of 10?250 g/L. Optimum growth was observed in the medium containing 100 g/L NaCl. HPLC-MS analysis revealed that this bacterium could synthesize both ectoine and hydroxyectoine as the main compatible solute. The yields of each compatible solute synthesized in the presence of 100 g/L NaCl were 175.5 mg/g and 47.9 mg/g for ectoine and hydroxyectoine, respectively. Maximum release rate of intracellular ectoines could be achieved within 5 min when Y cells experienced hypo-osmotic stress brought about by 0?30 g/L NaCl solutions. Hypo-osmotic saline solution with salinity of 10 g/L NaCl was the most appropriate for ectoine release during bacterial milking process. During the bacterial milking process eleven rounds of hyper/hypo osmotic shocks were exerted to the isolate and the total yields of synthesized and released ectoines were 6.0 g/L and 5.7 g/L, respectively. This corresponded to an average release rate of 64.5% and a high conversion rate of 128.9 mg/g. [Conclusion] Halomonas sp. Y is a moderately halophilic bacterium with quite high yield of ectoines. It could resist repeated osmotic shocks as characterized by ectoine release under hypo-osmotic stress and synthesis of ectoine under hyper-osmotic condition. Ectoine productivity was significantly improved by using bacterial milking process.

Abstract:[Background] According to relevant researches, waterlogged archaeological wood is vulnerable to degradation by microorganisms. Concerning the microbial damage of waterlogged archaeological wood, many studies have been carried out overseas, but few reported in China. [Objective] This study is aimed at analyzing the bacteria population in waterlogged archaeological wood and their degradation on wood when preserved in water. [Methods] Bacteria were identified by physiological and biochemical test and 16S rRNA gene sequence analysis. Typical bacteria strains were inoculated into wood that were used to test the wood degradation. The number of bacteria used to inoculate was 5×108 and the inoculated wood was cultured at 37 °C for 120 d. [Results] In total 53 strains were separated from F446 and the water sample. The dominant genus of these strains with number of 21, was Bacillus. Eleven of them belong to the genus of Brevibacterium, four are Brevundimonas, five are Alcaligenes faecalis, five are Altererythrobacter, two are Flavobacterium mizutaii, one is Pseudochrobactrum saccharolyticum, Lysinibacillus fusiformis, one Leucobacter aridicollis, one Paenibacillus, and one Ochrobactrum pseudogrignonense. Furthermore, strains A5 and A6 are likely new species of Paenibacillus and Altererythrobacter. Fifteen typical strains were selected to test the corrosion. Nine strains have extremely significant difference compared to the control. Some bacteria corroded wood but the corrosion rate was lower. It indicated that these bacteria could not cause severe corrosion to the wood of Pinus massoniana. [Conclusion] During a short period, bacterial driven wood-corrosion was not obvious when the archaeological waterlogged wood was preserved in water after excavated.

Abstract:[Background] Denitrifying anaerobic methane oxidation (DAMO) is an anaerobic oxidation process, in which nitrate/nitrite works as the electron acceptor, while methane works as the electron donor. DAMO has great significance to understand the global carbon and nitrogen cycle, reduce greenhouse gas emissions and develop new technologies for nitrogen removal from wastewater. [Objective] Feeding nitrate or nitrite as the electron acceptor, we investigated the differences on the performance of the denitrifying anaerobic methane oxidation reactors. [Methods] The SBR reactors in which nitrate/nitrite works as the electron acceptor were inoculated sludge mixture and then consecutively long-term incubation for 800 days, meanwhile we measured the nitrite and nitrate concentration in the reactors and calculated the conversion rate regularly. The abundance and diversity of functional microorganisms were investigated by 16S rRNA gene phylogenetic analysis. Then we analyzed the amount of the functional microorganisms by real-time fluorescence quantitative PCR technique. [Results] The DAMO bacteria were detected in the No. 1 reactor and No. 3 reactor which were fed with nitrite as the electron acceptor but the DAMO archaea was not detected. However in the No. 2 reactor which was fed with nitrite as the electron acceptor, the DAMO archaea and bacteria were detected simultaneously. The nitrogen removal rate of the three reactors kept a low value at the very beginning, then experienced a fast lifting phase and maintained a steady value at last. The time when nitrogen removal rate of No. 2 reactor started to increase rapidly was about 80 days later than No. 1 and No. 3 reactor. Its stable maximum rate is only 44.7% of No. 1 reactor and 40.3% of No. 3 reactor, spending more time reaching the stability. [Conclusion] The different substrate fed leads to the different results of enrichment. The DAMO archaea and bacterial synergistic system, which is enriched with nitrate as the electron acceptor, can coexist for a long time. DAMO archaea may be a limiting factor in the nitrogen removal rate in the synergistic system.

Abstract:[Background] In the Salmonella typhimurium, the c-di-GMP binding protein YcgR could inhibit flagellar motor speed by interacting with flagellar protein, which cause the bacteria stop migrate, generate biofilm and infect the host. However, the structure and functions of YcgR as well as the molecular mechanism of YcgR suppressing bacterial motion after binding to c-di-GMP are not clear. [Objective] In this study, YcgR protein was expressed and purified in recombinant E. coli, and then the c-di-GMP binding activity of YcgR were further characterized, which could lay a foundation for determining the structure of YcgR and clarifying how c-di-GMP binding protein YcgR slowing the movement of Salmonella typhimurium. [Methods] The recombinant E. coli was constructed for expressing YcgR protein, which was further purified by Ni-NTA and SEC (Size exclusion chromatography). After that, we predicted the structure of YcgR protein by comparing with other homologous family proteins, and the secondary structure of YcgR was determined by circular dichroism (CD). Finally, the binding parameters of YcgR and c-di-GMP were determined by isothermal titration calorimetry (ITC) and Protein Thermal Shift. [Results] Colony PCR and DNA sequencing results showed that the recombinant E. coli for expressing YcgR was successfully constructed. The size exclusion chromatography and polyacrylamide gel electrophoresis showed that the molecular weight of YcgR was 28 kD and existed as dimer in the supernatant. The structure of YcgR is highly similar to the homologous protein PP4396, which has a PilZ domain for binding c-di-GMP, and CD results showed that YcgR had a stable secondary structure. In addition, ITC and Thermal Shift indicated that YcgR had a strong and specific binding activity with c-di-GMP, and the Kd value was 50 nmol/L. [Conclusion] The YcgR protein from Salmonella typhimurium was successfully expressed in E. coli for the first time, and its c-di-GMP binding activity were also characterized in this study, which is very important for the study of the molecular mechanism of c-di-GMP binding protein YcgR regulating flagellin, and provide a new strategy for bacterial anti-infective therapy.

Abstract:[Background] Microlunatus phosphovorus is one of the important phosphorus accumulating organisms. It can accumulate polyphosphate (Poly-P) aerobically and hydrolyze Poly-P anaerobically, a process fine-tuned by specific regulatory genes. [Objective] To investigate Poly-P metabolic genes bound by Mlp21700, electrophoretic mobility shift assay (EMSA) was performed. [Methods] The coding sequence of Mlp21700 was amplified and cloned into pET28a to generate a recombinant plasmid pET28a-21700 that was then transformed into Transetta(DE3) to express the recombinant protein Mlp21700. Mlp21700 was purified under non-denaturing conditions. Promoter sequences of Poly-P metabolic genes were amplified by PCR, labeled with biotin, and used as probes in EMSA assays to investigate binding of Mlp21700 to the above probes. [Results] pET28a-21700 was confirmed by DNA sequencing and enzyme digestion. SDS-PAGE analysis indicated that Mlp21700 was highly expressed in soluble form. The purity of Mlp21700 surpassed 90% and the concentration reached 0.64 mg/mL. Our EMSA assays showed that Mlp21700 bound to the promoters of Mlp26610 (ppgk) and Mlp44770 (ppx). [Conclusion] Mlp21700 may directly regulate Mlp26610 and Mlp44770, and thus regulate Poly-P metabolism.

Abstract:[Background] Cronobacter sakazakii is an opportunistic pathogen transmitted by food, which affects mainly newborns, infants and immune compromised adults, with reported case fatality rates of 50%?80%. [Objective] The aim of this work was to investigate the antimicrobial effect of a natural plant-derived compound protocatechuic acid (PCA), and its effects on cell membrane permeability of C. sakazakii strains. [Methods] We determined the Minimum Inhibitory Concentrations (MICs) using agar dilution method, and growth curves were also measured. Changes in intracellular pH, membrane potential, intracellular ATP concentration, membrane integrity and cell morphology were measured to elucidate the cell membrane damage induced by PCA. [Results] The experimental results indicated that the MICs of PCA against C. sakazakii strains were 2.5?5.0 mg/mL. PCA decreased growth rate of C. sakazakii and increased the cell membrane permeability of cells, as evidenced by reduction of pHin, occurrence of cell membrane hyperpolarization/depolarization, intracellular ATP concentration decrease, reduction of membrane integrity and changes of cellular morphology in C. sakazakii cells after exposure to PCA. [Conclusion] These findings demonstrated that PCA had antimicrobial activity against C. sakazakii. It exerted antimicrobial action partly through causing cell membrane dysfunction and changes in cellular morphology. Considering its antimicrobial properties, together with its well-known nutritional functions, PCA has potential to be developed as a supplement in infant formula or other foods.

Abstract:[Background] Optically pure epoxides and vicinal diols are versatile chiral building blocks. Compared with chemical synthesis, biotransformation mediated by epoxide hydrolases (EHs), an environmental-friendly way, has become the current research focus. [Objective] A gene encoding EH was cloned from Phaseolus vulgaris and heterologously expressed in Escherichia coli. The catalytic characteristic of recombinant EH towards SO was studied. [Methods] By means of computer-aided analysis of EH primary structure, a hypothetical protein from Phaseolus vulgaris (PvEH4) was predicted to have EH activity. Using P. vulgaris total RNA as templet, the PvEH4-encoding gene, pveh4, was amplified by RT-PCR technique and expressed in E. coli BL21(DE3). To assay catalytic characteristics of PvEH4, asymmetric hydrolysis of styrene oxide (SO) was conducted by E. coli/pveh4 whole cells. [Results] The primary structure analysis showed that PvEH4 has the typical characteristics of conserved α/β fold EH motifs. SDS-PAGE analysis displayed that the apparent molecular weight of PvEH4 was 39.4 kD. The enantioselectivity (E value) of PvEH4 towards SO was 10.1, while regioselectivity coefficient, αS and βR was 99.5% and 82.5%, respectively. As the conversion ratio reached 68.1%, (R)-SO with 99.9% ees and 31.9% yield as well as (R)-PED with 92.3% eep and 65.6% yield were simultaneously obtained. [Conclusion] The excavated PvEH4 not only increases the number of plant EHs, but also provides a good reference for EH modification.

Abstract:[Background] Streptomyces sampsonii KJ40 is an actinomycete with functions of disease prevention and promoting plant growth, it has the potential as a biological pesticide. However, there is no relevant study in the genome of S. sampsonii until now, limiting the research of its functional genes, metabolites synthesis pathway and comparative genomics etc. [Objective] To analyze the genome information of the S. sampsonii KJ40 strain, and to research the mechanism of functions of the strain, and its secondary metabolite genes. [Methods] The whole genome of KJ40 strain was sequenced on the Illumina HiSeq platform, and then sequenced reads were assembled, the genes were predicted, the gene annotation, secondary metabolite biosynthesis and synteny were also analyzed with softwares. [Results] In the whole genome, 9 scaffolds and 578 contigs were obtained. The total length was 7 261 502 bp, the average GC content was 73.41%. It contained 6 605 genes, 1 260 tandem repeat sequences, 804 minisatellite DNAs, 67 microsatellite DNAs, 90 tRNAs, 9 rRNAs, and 19 sRNAs. Among them, 2 429, 3 765, 2 890, 6 063 and 1 911 genes were able to annotate in COG, GO, KEGG, NR and Swiss-Prot databases respectively. 21 secondary metabolite biosynthetic gene clusters were also obtained. The sequencing data from this article are available in the GenBank database (accession number LORI00000000). There were 1 711 proteins clustered among S. sampsonii KJ40, Streptomyces coelicolor A3(2) and Streptomyces griseus subsp. griseus NBRC 13350. The analysis of synteny indicated that genome rearrangement and translocation happened among these genomes. [Conclusion] Our results show the genome information of KJ40 strain, it gives evidence that KJ40 is linked to disease prevention and promoting plant growth, and provided reference for understanding secondary metabolic synthesis pathway of Streptomyces, which is of great significance to the future research of S. sampsonii.

Abstract:[Background] Ganoderma lobatum is a species of Ganoderma spp., which and can be used as a medicinal herb in the folk. However, there is no scientific research on the chemical composition and pharmacological activity of Ganoderma lobatum. [Objective] To explore the medicinal value of Ganoderma lobatum, the antitumor and immunological activity of Ganoderma lobatum were studied, with the Ganoderma lingzhi as a reference. [Methods] Triterpenoids and polysaccharides in the two species of Ganoderma were analyzed by chemical and instrumental analysis, and their antitumor and immunological activity were studied. [Results] There were not significantly different in the contents of triterpenoids in Ganoderma lobatum and Ganoderma lingzhi, which were 1.14% and 1.21%, respectively. However, the kinds of triterpenoids in the two species of Ganoderma was distinctive. The content of polysaccharides in Ganoderma lobatum were slightly higher than that in Ganoderma lingzhi, which were 3.60% and 2.67%, respectively. Meanwhile, there was a difference in the molecular weight distribution of polysaccharides in the two fruiting bodies. Both of the ethanol extracts had inhibitory activity on K562 and SW620 cell. Among them, Ganoderma lobatum has a strong inhibitory activity on SW620 cells with IC50 of 52.5 μg/mL. Furthermore, both of them aqueous extracts could promote RAW 264.7 cells to release NO, which illustrated that both have certain immunological activity. [Conclusion] Ganoderma lobatum has good antitumor and immunological activity, which could be used as a source of raw material potential materials for medicinal development.

Abstract:[Background] Ganodema lingzhi Sheng H. Wu, Y. Cao & Y.C. Dai. is a widely regarded medicinal and edible fungus. Spectacularly, it was used as a traditional medicine and health food in China for thousands of years and the cultivation of G. lingzhi has been expanding rapidly recent years. Polysaccharides are considered to be the most important active ingredient in G. lingzhi. [Objective] This article focused on the extraction, purification, structure and immunoregulatory effects of a novel polysaccharide purified from the fruit bodies of G. lingzhi. [Methods] The polysaccharides of G. lingzhi (GLP) were extracted with boiling water and purified by DEAE cellulose-52 column and Sephadex G-100 column. The high performance gel permeation chromatography (HPGPC), PMP derivatization and FT-IR method were used to analysis molecular weight, monosaccharide composition and backbone structure, respectively. The splenocyte proliferation was analysed by MTT assay. The potency of polysaccharides on the phagocytosis and cytokine secretion of RAW 264.7 cells was determined by commercial kit. [Results] The molecular weight of GLP was 1.93×104 Da, the monosaccharide composition of GLP was mainly composed of glucose, galactose and mannose, with a ratio of 3.3:1.3:1.0. The anomeric carbon of GLP has a β configuration. GLP resulted in a significant increase of lymphocyte proliferation and could also enhance the effect of Con A-induced T lymphocyte proliferation and the stimulation index of LPS-induced B lymphocytes. In addition, the phagocytosis and cytokine secretion of RAW 264.7 cells can be promoted by GLP. [Conclusion] GLP may be developed as a potential immunoregulatory drug.

Abstract:[Background] Medicinal plants constitute the huge diversity of endophytic bacteria. These microbes have potential to synthesis of numerous novel compounds that can be exploited in pharmaceutical industries. [Objective] For the purpose of exploring the pharmaceutically potential of the endophytes in medicinal plants and finding antimicrobial secondary metabolites, endophytic bacteria diversity of Aspidistra Ker-Gawl. was investigated. [Methods] After surface sterilization, the tissue fragments of 13 plants, which were classified into 9 different species, were inoculated onto 5 diverse isolation media. Duplicate isolates were eliminated by colony properties. Based on 16S rRNA gene sequencing results, Neighbour-Joining phylogenetic tree was constructed to analyze the endophytic bacteria diversity in Aspidistra spp. All the non-duplicated isolates were fermented with two kinds of media. The antimicrobial activities of the endophytic motablisms were detected with 5 testing strains, including Mycobacterium smegmatis ATCC 700044, Xanthomonas oryzae PXO99A, Candida albicans ATCC 10231, Klebsiella pneumoniae ATCC 700603 and resistant strain Enterococcus faecalis HH22. [Results] A total of 234 endophytic bacteria were isolated from different plant tissues and 156 non-duplicated strains were confirmed after colony properties checking. These endophytic bacteria strains were classified into 3 phyla, 10 orders, 22 families and 29 genera. Notably, Streptomyces sp., Bacillus sp., Microbacterium sp., Paenibacillus sp. and Rhizobium sp. were the predominant species in Aspidistra spp., and 6 potential novel species were found. The fermentation broth from 38 isolates (23.7%) showed antimicrobial activities. [Conclusion] The data of this study showed an unexpected diversity of endophytes inside the Aspidistra tissues, and suggested that endophytic bacteria of the Aspidistra tissues are promising sources of new natural secondary metabolites with favorable antimicrobial activities.

Abstract:[Background] Helicobacter pylori (H. pylori) has been described as a main pathogenic factor for gastric cancer. Protein product of the cytotoxin associated gene A (CagA) has been known as the only oncoprotein that is secreted and injected into gastric epithelial cells by the bacteria, thus mediating the development of gastric cancer. [Objective] To compare the sequence difference of CagA between the East Asian strain and Western strain of H. pylori, and explore the effects of H. pylori-CagA on the proliferation and apoptosis of gastric cancer cells. [Methods] DNA and amino acid sequences of CagA in East Asian strain and Western strain were analyzed. A eukaryotic expression vector containing the cagA gene from each strain was constructed and transferred into AGS gastric cancer cells. The CagA protein was assessed using Western blot. Cell growth curve and apoptosis were determined using CCK8 and flow cytometry, respectively. [Results] Comparison of the DNA and amino acid sequences in the CagA between the two strains revealed some characteristic differences. The expression vectors of H. pylori-cagA gene were constructed successfully and named as GZ7/cagA (East Asian strain) and 26695/cagA (Western strain). Compared with cells transfected with the empty vector, the cells transfected with the East Asian strain and the Western strain derived cagA expressed CagA proteins, but there is no difference in protein levels between the two groups. The cells transfected with the East Asian strain and the Western strain derived cagA grew significantly fast or slower, respectively (P<0.05). The apoptotic rates of cells expressing the East Asian strain derived CagA and the Western strain derived CagA were 7.23±0.96 and 9.17±1.40, respectively, both being higher than that of the cells expressing the empty vector (5.03±0.63) (P<0.05). [Conclusion] There are structural and functional differences in the CagA between the East Asian and Western strains of H. pylori. While the one in the East Asian strain promotes the proliferation, Western CagA inhibits the proliferation of gastric cancer cells. However, the CagA in the both strains promotes apoptosis of the cells.

Abstract:[Background] The abuse of antibiotics accelerated the emergence of antibiotic-resistant of Staphylococcus aureus, and the infections caused by these superbugs have become one of the most challenging tasks in clinic. Reconstruction of the transmembrane signal transduction process of AgrA/C pathway in vitro will be very helpful in solving the problem of antibiotic resistance in S. aureus and developing new antibiotics against these bacteria. [Objective] To realize in vitro construction of an AgrA/C two component signal transduction model for investigating mechanism of two component signal transduction in S. aureus and drug screening. [Methods] AgrA and AgrC proteins were expressed in Escherichia coli C43(DE3) and purified by affinity and size exclusion chromatography, and then their biological activities were analyzed. The AgrA/C two component signal transduction model was constructed in vitro using detergent-mediated method and the validity of the model was verified through the electrophoretic mobility shift assay (EMSA). [Results] The purity of AgrA and AgrC was over 90%. AgrA protein can bind to the target DNA and AgrC has the kinase activity. The AgrA/C two component signal transduction model was constructed in vitro. The model could enhance the delay of DNA mobility shift by AgrA, indicating the artificial simulation model can transfer signal. [Conclusion] we designed and constructed the AgrA/C two component signal transduction model in vitro successfully. This model system is expected to be a screening platform for new antibacterial drugs targeting S. aureus.

Abstract:[Background] Taisui has a history of use in China dating to ancient times. In Shennong Bencaojing, it is listed as a medicine capable of supporting healthy qi, strengthening the body’s constitution and promoting longevity. However, as an organism, its constituents and classification are still unclear causing inadequate identification of its medicinal value. It is highly necessary to analyze its components objectively using modern biological analytical techniques. [Objective] To determine the existence of prokaryotes in Taisui, and to analyze the types of bacteria and the relationships among them. [Methods] The Illumina MiSeq 2×250 platform was used to carry out sequencing of V4 regions of the 16S rRNA gene of bacteria in the Yellow River Taisui. FLASH and other software packages were used to analyze the data. [Results] A total of 626 operational taxonomical units were found, involving 19 phyla, 49 classes, 80 orders, 107 families, and 112 genera. The top 10 dominant bacteria at the genus level were found to be Bacteroides, Coprococcus, Escherichia, Ruminococcus, Lactobacillus, [Ruminococcus], Oscillospira, Faecalibacterium, Shewanella, and Halomonas. [Conclusion] There are different microbial communities of bacteria in the Yellow River Taisui.

Abstract:Nematophagous fungi (NTF) serve as natural enemies of nematodes, which are potential biocontrol agents for plant-parasitic nematodes. NTF can attack and kill nematodes through producing specialized capturing devices, adhesive conidia or toxins. In recent years, with the advances in sequencing technology and the application of bioinformatics, more and more fungal genomes have been sequenced and reported. At present, genomes of seven NTF, including the nematode-trapping fungus Arthrobotrys oligospora, the egg and cyst-parasitic fungus Pochonia chlamydosporia and the endoparasitic fungus Hirsutella minnesotensis, etc., have been sequenced and reported. In this paper, the genomic characteristics, the expansion of virulence-related gene families, the regulation of trap formation and evolution of NTF were systematically summarized, and key problems of NTF in the omics era were reviewed.

Abstract:The oceans are the largest carbon sink in the world and regulate the climate change through carbon fixation, the exchange of materials and energy with the atmosphere. As the global climate change becomes intensified, ocean carbon sink has become a popular research topic and one of major means to reduce global warming. Marine microbes play a pivotal role in ocean carbon fixation and ocean carbon cycling, makes an important meaning to ocean carbon sink. This paper summarizes the significance of unicellular marine protists in ocean carbon fixing and storage with an emphasis on members of Labyrintholomycota and their roles in marine carbon recycling and ocean secondary production. For better understanding of the processes and mechanisms for ocean carbon sink, several important topics and potential solutions were discussed. Hopefully, it will provide some useful information and guidelines for the biological aspects of ocean carbon sink.

Abstract:With the development of eutrophication in freshwater lakes in the past decades, harmful cyanobacteria blooms (CyanoHABs) have become more frequent and with worse extends around the world. Many of these CyanoHABs produce cyanotoxins, often microcystins (MCs), and threaten human health and the environments, MCs are chemically stable, however they can be effectively degraded through microbial process, which has a great potential in applications for environment-friendly water treatments and environmental protection. In this review, we summarized the chemical structure, toxicity and degradation of microcystins, with the emphasis on microbial decomposition processes of microcystins and their potential application in water treatment and environmental protection.

Abstract:The modernization is the most urgent to traditional Chinese medicine research. Microbial biotransformation can help to solve many difficult problems of traditional Chinese medicine research. The article summarizes the characteristics of microbial biotransformation, enzyme systems and reaction types, and analyze the influence of Chinese medicine microbial biotransformation. The conclusions were that the enzyme systems had widely variability, strong selectivity, mild and controllable reaction conditions, multiple reaction types to all active ingredients of traditional Chinese medicine, and the technology was very suitable for the daily and industrial production. After biotransformation, the effects of drugs can be improved, reduce the toxicity, remove the impurities, help to the metabolism in vivo and produce new drug ingredients. The Chinese medicine combinated with microbiology model will significantly promote the modernization of traditional Chinese medicine process.

Abstract:Fusarium is a large genus of filamentous fungi and widely distributed in soil and associated with plants. Because of its great morphological variation, the classification of Fusarium has always been a thorny problem in the academic circle. With the PCR technology, the identification methods of molecular markers and rDNA analysis of Fusarium improved the accuracy of morphological identification, and laid a foundation for further research and application of Fusarium. Fusarium can produce a variety of key enzymes, including cellulase, pectinase and xylan hydrolase. The important drugs or drug intermediates can be obtained via the bio-transformation, so they have potential commercial value. Fusarium can degrade a variety of environmental pollutants and has important potential in environmental protection. In particular, biological ethanol can be produced through biological transformation to solve the energy crisis. In the paper, the identification and enzyme production of Fusarium species are described in detail. The properties of the main enzymes from Fusarium and the application in the production of bioethanol are reviewed in detail.

Abstract:For the purpose to increase interests in knowledge learning, operation techniques training, innovative thinking developing, and quality education promoting of Microbiology and Examination Technology experiment course for medical inspection technology students, a micro-course teaching method on WeChat platform were developed and practiced. The results indicated that the teaching method could effectively enhance the degree of liking of the professional students to the course and help them to enhance the course of academic achievement, at the same time can effectively enhance the students attention on the cutting edge of the discipline.

Abstract:With the rapid development of Internet technology and mobile terminal equipment, online and offline blended teaching mode has developed rapidly. Based on the analysis of the problems existing in the current higher vocational course teaching and the solutions, this article introduces the exploration and practice of blended teaching in the course of Microbiology online and offline, including online teaching platform selection, teaching content of the four aspects of reconstruction, the design and implementation of teaching, teaching evaluation and assessment. At the end, The effect and reflection of the online and offline blended teaching mode was discussed. The online and offline blended teaching mode adopts fragmented teaching resources, breaks through the limitation of teaching time and space, improves the students’ self-learning ability, and improves the teaching quality of Microbiology course.

Abstract:[Background] Vibrio parahaemolyticus, which is highly pathogenic and harmful to public health, is a common contaminating microorganism in chilled food and meat products. To keep them fresh, imported and exported food are often refrigerated or frozen to prevent microorganism growth during transportation and machining. However, residual V. parahaemolyticus can enter a viable but non-culturable (VBNC) state, which poses potential risks. [Objective] This study aimed to establish a method to detect V. parahaemolyticus in a VBNC state in frozen food and to explore its applicability. [Methods] A solution containing V. parahaemolyticus was added to homogenized Atlantic salmon matrix to a final concentration of 6.6×105 colony forming units (CFU)/mL. Aliquots of the mixture were induced for 10, 20, 30, and 50 days at ?20 °C. A propidium monoazide (PMA)-based quantitative real-time PCR (qPCR) method was established to detect the V. parahaemolyticus in the samples of different frozen periods and compared with the results of qPCR and plate culture methods. [Results] The established PMA-qPCR method showed good specificity and no cross-reaction with other negative reference strains. The sensitivity of the method was also high and the quantitative limit was 19.8 CFU/mL. The variation coefficients (CV) of Cq values were all below 1.5%. The standard curve was y=?3.272x+45.310 and the linear regression coefficient, R2 was 0.996. The quantitative range was 1×102 to 1×109 CFU/mL. After the low temperature induction from 10?50 d, the Cq value of the qPCR method was between 26.32 and 27.34 which showed little change. However, the Cq value of the PMA-qPCR increased from 26.43 to 38.84, showing a significant increase in the number of dead bacteria. After comparison and statistical analyses, the number of live bacteria detected by PMA-qPCR was higher than that of plate culture, and the difference was significant (P<0.05). [Conclusion] The established PMA-qPCR method had high specificity and sensitivity and could effectively inhibit the amplification of dead bacteria. It was also an effective and fast method to detect VBNC bacteria, which could overcome the limitations of the traditional plate culture method.