Abstract:[Objective] L-Ornithine and L-Citrulline producers were constructed based on the L-Arginine producer Corynebacterium crenatum SYPA5-5 and their fermentative performances were evaluated. [Methods] argF encoding ornithine carbamoyltransferase (OTC) and argG encoding argininosuccinate synthase (ASS) were deleted respectively in SYPA5-5 to block the biosynthetic pathway that converting L-Ornithine and L-Citrulline to L-arginine. Two recombinant strains SYPA5-5△argF and SYPA5-5△argG were constructed. The influence of different L-arginine concentration on growth and amino acids accumulation of the recombinant strains were determined. [Results] SYPA5-5△argF kept well growth status with the fermentation media supplied with 0.3 g/L L-arginine and the growth rate was similar to SYPA5-5. SYPA5-5△argF had the capacity of producing 21.5 g/L L-Ornithine. On the contrary, L-arginine had no use for SYPA5-5△argG to enhance the productivity of L-Citrulline even though it contributed to improve cell growth. SYPA5-5△argG produced 15.2 g/L L-Citrulline with the original media without adding L-arginine, and it produced 6.8 g/L L-glutamate simultaneously. [Conclusion] Deleting argF and argG respectively in SYPA5-5 made it accumulate high concentration of L-Ornithine and L-Citrulline. These expanded the applied scope of SYPA5-5 in amino acids industry.

Abstract:[Objective] D-1,2,4-butanetriol is widely used in military and medicine industry. To realize the biosynthesis of D-1,2,4-butanetriol from D-xylose directly, xylose metabolism of Escherichia coli W3100 was modified. [Methods] The D-xylose dehydrogenease gene xylB from Caulobacter sp. and benzolyformate decarboxylase gene mdlC from Pseudomonas putida were expressed in E. coli W3100, resulted in a recombinant E. coli (pEtac-mdlC-tac-xylB). [Results] When cultivated with 30 g/L D-xylose at 30 °C for 48 h, the titer and molar yield of D-1,2,4-butanetriol reached 0.9 g/L and 4%. [Conclusion] Our results may serve as a start-point for further genetic engineering to enhance the titer of D-1,2,4-butanetriol.

Abstract:[Objective] In order to increase the laccase productivity and reduce the production cost, solid-state fermentation (SSF) (using hickory hull) medium for Trametes hirsuta D2 has been studied. [Methods] The effects of supplementation with carbon and nitrogen sources, ratio of carbon and nitrogen source and the content of hickory hull on laccase production were investigated. [Results] The hickory hull was a good support for mycelial growth during laccase fermentation, and the corn flour and rapeseed meal were found efficient and selected as additional nutrition for laccase fermentation. The optimum solid materials in medium were consisted of 40% (w/w) hickory hull, 24% (w/w) corn flour and 36% (w/w) rapeseed meal. Under these conditions, the highest laccase activity (126.8 U/g dry substrate) was achieved after 6 days of cultivation. [Conclusion] The higher laccase productivity and lower production cost could facilitate industrial application of laccase.

Abstract:[Objective] In previous study, we constructed a metabolic pathway to synthesize poly(3-hydroxypropionate) (P3HP) from glycerol. But two main issues, the reducibility imbalance and plasmid loss, still remained. In order to increase the yield of P3HP, we must solve those problems. [Methods] The 1,3-propanediol (1,3-PDO) dehydrogenase gene was cloned from Klebsiella pneumoniae and a P3HP and 1,3-PDO co-product strains was built to solve the reducibility imbalance in cell. The genes encoding glycerol dehydrogenase and its reactivatase were inserted into the Escherichia coli chromosome by suicide vector-mediated homologous recombination to improve the stability of plasmid. [Results] After optimization of fermentation condition, our recombinant strain produced 2.7 g/L P3HP, two times higher than the previous report, and 2.4 g/L 1,3-PDO was also obtained at the same time. [Conclusion] The production of P3HP by recombinant Escherichia coli from glycerol was improved and has great potential in various industrial applications.

Abstract:[Objective] To understand the diversity of culturable fungal resource isolated from soil in different habitats (intertidal zone, transitional zone from sea to mangrove, mangrove forest zone) of mangrove ecosystem. [Methods] Diluted sediment suspensions were spread on plates to isolate fungi. The phylogenetic and genetic diversity of fungal isolates was analyzed using morphology and ITS rDNA sequences, respectively. [Results] In total 257 fungi belonging to 21 genera and 28 species were isolated from soils in 3 different habitats of mangrove ecosystem. Penicillium, Aspergillus and Trichoderma were the dominant fungal populations. Fungal populations from different habitats or different depths were different. Spatially, diversity index from the mangrove forest zone were higher than those from the other two habitats; vertically, diversity index of surface-layer samples were higher than those of deep-layer samples in intertidal and transitional zones, while diversity index of deep-layer samples were higher than those of surface-layer samples in mangrove forest zone. [Conclusion] The ecological distribution characteristics of culturable soil fungi in mangrove ecosystem provided background data of fungal resource for us to explore potential applications.

Abstract:[Objective] Biological soil crusts (BSCs) play an important role in restoring the ecological environment and constraining soil desertification. Microorganisms are important in the development of BSCs. However, the investigation on the microbial composition of BSCs is still limited now, especially is rare about archaea. [Methods] We constructed and analyzed archaeal 16S rRNA gene library to discover the diversity and phylotype composition of BSCs archaea from Desert Hunsandake, compared the variation between summer and winter. [Results] BSC samples were thin and brown with low levels of nitrogen and phosphate nutrients. The coverages of both libraries of August and November were over 95% and strongly representative. In total 142 archaeal 16S rRNA sequences were obtained from the two libraries and these sequences were divided into 10 operational taxonomic units (OTUs) with the cutoff value of 0.03. In both libraries the predominant OTU was the same, probably a unique group in desert. All sequences obtained from this study were originated from members of Thaumarchaeota, the third phylum of Archaea, but a large difference in community structure was observed between the two libraries of August and November. Only one unique OTU was found in August and four in November. Archaeal diversity in BSCs is low and yet the diversity of November was higher than that of August. [Conclusion] Archaea in light-colored BSCs from temperate desert is dominated by the Thaumarchaeota species with lower diversity and the community structure largely varies with season changing.

Abstract:[Objective] To study the community composition of cellulase-producing bacteria in papermaking wastewater oxidation pond, and to screen cellulase-producing bacteria to enrich the microorganism resources for industrial application and biological treatment of environmental pollution. [Methods] The community compositions and the phylogeny of cellulolytic bacteria in the papermaking wastewater oxidation pond were studied on the sequences of the 16S rRNA genes. Cellulase secreted by these bacteria were characterized under different pH value. [Results] The cellulolytic bacteria in the papermaking wastewater samples were diversified. They could be phylogenetically classified into Firmicutes, Actinobacteria, Alpha-proteobacteria and Gamma-proteobacteria and further divided into 15 species at a higher resolution. The communities in liquor-mud mixture and sludge outlet of black liquor have the most abundant diversity, and contained six to seven species. These rich diversities maybe owing to the marginal effect and mild pH condition of the environments. Due to the stringent pH condition, the microbial diversity of the lower layer of pond was relatively poor, and Bacillus was the dominant group. The types of cellulase produced by the bacteria in oxidation pond not only contained acidic cellulase, but also contained abundant alkaline cellulases and neutral cellulases. [Conclusion] A number of excellent cellulase-producing bacteria were screened with potential applications.

Abstract:[Objective] We selected a strain with high capability of denitrifying and phosphorus removal. Besides we established an assay of sandwich hybridization with S1 nuclease protection to analyze the microbial community of this strain in fermentation process. [Methods] We used anaerobic culture in a phosphorus deficient medium, aerobic culture in a phosphorus-rich medium and nitrate-reducing experiment for bacterial isolation. Physiological and biochemical tests and 16S rRNA gene probing technique were used to identify the selected strain. A set of DNA probe was synthesized and used in quantification. [Results] The selected strain was identified as Pseudomonas sp. and named as LY10. The phosphorus removal rate of LY10 was 90.31% under aerobic condition in 24 hours, the denitrifying and phosphorus removal rate were 84.71% and 89.37%, respectively, under anoxic condition in 48 hours. Bacterial detection with the reported technique showed LY10 could be well identified from other strains such as Commonas with the probe Probe-P. sp. which was complementary to the conservative region of 16S rRNA of Pseudomonas genus. The cell density range was from 103 to 106 cells per milliliter and the equation was y=?0.967 87+0.372 99x (R2=0.996 7, n=5). [Conclusion] The selected strain showed strong activity on removing compounds with N and P, thus it can have potential application in industrial bio-denitrifying and phosphorus removal.

Abstract:[Objective] This study tried to find the key factor which affected the soil microbial communities and enzyme activities along an altitudinal gradient in forest ecosystem in Sejila mountains. [Methods] This study tested six soil enzyme activities (β-glucosidase, phenol oxidase, protease, L-asparaginase, urease and acid phosphatase) and soil microbial communities structures (bacteria, fungi, gram-positive bacteria, gram-negative bacteria and actinomycete). [Results] Soil physicochemical properties such as moisture, TOC, TN, C/N and pH had no significant changes along the altitudinal gradient. Moreover, soil enzyme activities such as β-glucosidase, phenol oxidase, protease, L-asparaginase and acid phosphatase had no significant change along the altitudinal gradient. However, bacteria, fungi, gram-positive bacteria, gram-negative bacteria and actinomycete biomass all showed a mid-domain effect along the altitudinal gradient, which reached higher values at 3 900 and 4 000 ms.a.l. Person correlation analysis showed that pH was the key factor structuring microbial communities, yet mean annual temperature had no significant correlation with microbial communities and enzyme activities. Instead, soil physicochemical properties such as TOC, TN, WSOC and WSON were key factors in enzyme activities. [Conclusion] These results suggested that elevational gradients had an important influence on soil microbial communities, but not on soil physicochemical factors and soil enzyme activities.

Abstract:[Objective] Hydrogen peroxide-mediated ‘mitohormesis’ can mimic calorie restriction to extend yeast lifespan, but whether both share common mechanisms remains unknown. [Methods] Yeast chronological lifespan was determined by time-course colony counting. The fluctuations of ATP-binding cassette transporter gene expression profiles and lipid metabolism modes were analyzed by microarray chips. The dynamic changes of superoxide dismutase activities were compared by enzymatic assays. [Results] After treatment by calorie restriction, hydrogen peroxide or artesunate, yeast chronological lifespan was prolonged. Cellular detoxification-related transporter genes were downregulated or unchanged, whereas long-chain fatty acid transport-enhanced peroxisomal transporter genes as well as sterol uptake-accelerated plasma membrane transporter genes were upregulated. Accordingly, genes for lipid degradation such as the β-oxidation of fatty acids were upregulated, whereas genes for lipid synthesis including the extension and unsaturation of fatty acids were downregulated. Among different treatment groups, increase of Mn-SOD activity for mitochondrial hydrogen peroxide generation led to upregulation of antioxidant enzyme genes for hydrogen peroxide degradation and conversion. [Conclusion] Hormesis and calorie restriction exerting longevity-promoting effects depend not only on antioxidant enzymes-catalyzed reactions for scavenging reactive oxygen species, but also on ATP-binding cassette transporters-mediated lipid transport and subsequent lipid degradation and reutilization.

Abstract:[Objective] We constructed a recombinant Pichia pastoris GS115 strain to produce AMP deaminase and optimized the fermentation conditions. [Methods] The AMPD gene was amplified from Streptomyces murinus and cloned into the expression plasmid pGAP9K, the recombinant expression plasmid was transformed into Pichia pastoris GS115 by electrotransformation. Furthermore, we determined the AMP deaminase activity of positive transformants. Finally, we optimized the fermentation conditions. [Results] We constructed a recombinant P. pastoris GS115 strain (P. pastoris GS115/pGAP9K-AMPD) that showed AMP deaminase activity. The fermentation conditions of the recombinant strain were studied. The results showed that the optimum fermentation medium of the recombinant strain contains 2% glycerin, 2% peptone, 1% yeast extract, 0.5% KH2PO4 and 0.05% MgSO4·7H2O (pH 6.0). And the recombinant enzyme activity of fermentation supernatant was 2 230±60 U/mL with 3% of inoculation amount, 24 hours of seed time, 96 hours for 200 r/min at temperature of 30 °C. [Conclusion] We constructed a recombinant P. pastoris GS115 strain that showed AMP deaminase activity about 2 230±60 U/mL under optimized fermentation conditions. This research is helpful to advance the industrial production of AMP deaminase.

Abstract:[Objective] aiming to screen out Bacillus strains which promoted growth of Eucalyptus seedlings, estimate relationship between ACC deaminase activity and seedling growth performances, and reveal preliminarily mechanism of growth promotion by Bacillus strains. [Methods] Pot experiment was conducted for Eucalyptus seedlings inoculated by 32 strains of Bacillus which were isolated from the soil under Eucalytus plantation in Yangjiang and Guangzhou City, Guangdong Province, and ACC deaminase activity of the strains as well as nitrogen and phosphorus contents of the seedlings were measured. [Results] The results showed that inoculations of strains 2306, 2301 and 2403 could increase significantly height and biomass growth of Eucalyptus seedlings, and strain 2306 was the best, relevant seedling height and biomass were 53.1% and 190.2% higher than control. [Conclusion] ACC deaminase activity of Bacillus strains was remarkably correlated with seedling height and biomass, and these three strains could also increase nitrogen and phosphorus contents of Eucalyptus seedlings. The findings will increase growth-promoting microorganism germplasm resources of Eucalyptus plantation and facilitate development of microbiological fertilizers for Eucalyptus.

Abstract:[Objective] The actinomycete strains with high nematicidal activity against Bursaphelenchus xylophilus were isolated and identified. The virulence factors were determined. [Methods] Strains were selected by plate activity test and insecticidal activity detection by metabolites. Strains were identified by phenotypic and genotypic characteristics. After analyzing the primary characteristics of the activity substances in the fermented broth, the virulence factor was purified and identified using alcohol precipitation, extracted by chloroform, chromatographer, and GC-MS. [Results] Seventy nine actinomycetes were isolated and six strains which had nematicidal activity to B. xylophilus were totally found from the rotten wood, dry branches and fallen leaves in Baotianman Natural Reserves in Nanyang, Henan Province, China. Among which, an actinomycete strain C620, showed the highest nematicidal activity to B. xylophilus. The culture supernatant from the strain C620 separately killed 60.0% and 81.5% of B. xylophilus within 48 h and 60 h, which suggested the high toxic activity toward the nematodes. The actinomycete was classified to be Kitasatospora genus. The virulence factor in the fermented broth of C620 showed strong thermal stability, light stability and storage resistance. The bioactive substance was stable in alkaline environments and can be dissolved in water. Finally, the compound was found to be 1-phenyl-3-(2-pyridyl)-5-pyrazolone. [Conclusion] An actinomycete strain Kitasatospora sp. C620 with high killing activity against B. xylophilus was isolated and the virulence factor was 1-phenyl-3-(2-pyridyl)-5-pyrazolone.

Abstract:[Objective] To obtain Bacillus subtilis A7 and explore its clinical use. [Methods] A7 was screened through milk plate and identified by conventional bacteriology and 16S rDNA. Growth promoting effect on Jian carp was explored via clinical feeding experiments. [Results] Diameter of protein hydrolysis circle was 27.5 mm. The optimal solid fermentation conditions were: temperature 28 °C, inoculation amount 5% (1.2×109 CFU/mL), ratio of material to water 1.0:1.2, fermentation time 72 h. Diets with 0.5%, 1.0%, 1.5% A7 could promote Jian carp growth, and 1.0% A7 added displayed the highest weight gain and protein efficiency, and the lowest feed coefficient, difference was significant comparing with product group and blank group (P<0.05). With increasing dosage of A7, protease and amylase activity in hepatopancreas and intestine of all test groups increased first, then decreased, and compared with product group and blank group, 1.0% added was also the best (P<0.05). Besides, fish fed with A7 had obvious trend of an increase content in crude protein and a decrease in crude fat comparing with blank group (P<0.05). [Conclusion] Fish baits with A7 can promote growth, reduce feed coefficient, increase protease and amylase activity, and improve fish flavor.

Abstract:[Objective] This study is to research the influence of foot-and-mouth disease virus (FMDV) leader protein for virus infectivity. [Methods] Two full-length infected cDNA clones were constructed based on O/HN/93 strain cDNA using reverse genetic technique which contain the leader protein of Chinese isolates O/CHN/Mya98/33-P and O/CHN/Mya98/HN1. Though real-time fluorescent quantitative PCR detecting the situation of IFNβ and OAS mRNA transcription, when pig kidney primary cells were infected the two different chimeric viruses. [Results] We found that the proliferation ability of chimeric virus rOHN1Lab is weaker, and the content of IFNβ and OAS it induced is higher. However, the proliferation ability of chimeric virus rO33Lab relative to rOHN1Lab is higher, and the content of IFNβ and OAS which induced is lower. [Conclusion] This study suggests that the leader protein of the Foot and mouth disease Chinese isolates O/CHN/Mya98/33-P have the stronger ability to resist IFNβ mRNA transcription, which lay the foundation for further identification of FMDV leader protein critical sites for resisting host innate immunity.

Abstract:[Objective] Pseudomonas aeruginosa, an opportunistic human pathogen, possesses a type III secretion system (TTSS) as one of the major virulence factors by which it secrets and translocates effector proteins into human host cells. In this study, five compounds which influence the expression of TTSS were identified from cinnamic acid derivatives. [Methods] The transcriptional reporter of exoS gene on plasmid pAT-exoS was used to monitor the exoS expression in the wild type strain PAO1 with the candidate compounds. [Results] Among 21 compounds, three compounds decreased the expression of exoS gene, whereas two compounds increased the expression of exoS gene. In addition, the compounds TS128, TS143 and TS160 showed inhibitory effect in bacterial growth. Western blot assay further showed that the level of ExoS was altered when the medium was added TS108 and TS165. The expression of exoS was partly restored to the wild-type when the plasmid p35-exsA which containing the exsA gene was introduced into PAO1. However, there is no difference of the exoS expression in the rsmY rsmZ double mutant with inhibitors TS108 and TS165. In addition, the production of N-Acyl homoserine lactones, which is positively regulated by the Gac/Rsm signaling pathway, is not affected with the inhibitors TS108 and TS165. [Conclusion] Our results suggest that the inhibitors TS108 and TS165 affect the expression of exoS through the transcriptional regulator ExsA instead of the Gac/Rsm regulatory pathway.

Abstract:[Objective] To verify the polymorphism of SSR markers analyzed with electronic PCR in Volvariella volavacea genome by using real PCR. [Methods] SSR loci in V. volvacea genome were identified with MISA software and the primers of the SSR molecular markers were developed with Primer3.0 software. The polymorphism of SSR markers were analyzed with electronic PCR and then verified by PCR. [Results] The 658 pairs of randomly selected SSR primers were checked by real PCR in 2 homokaryon strains, V23-1 and PD19, and the results show that 28.6% of SSR primers have the polymorphism. When the tested SSR loci belong to the type that had no length difference analyzed by the electronic PCR, only 4.8% SSR primers had the polymorphism. When the tested SSR loci selected from the group in which the length difference among the electronic PCR products of different genome was more than or equal to 3 bp, the true polymorphous SSR primers reached 48.3%. [Conclusion] The real PCR confirmed that it is more efficient to select polymorphous SSR markers with electronic PCR.

Abstract:[Objective] To identify red pigment produced by Beauveria nivea and further research the relationship between red pigment and cyclosporine A (CysA). [Methods] the red pigment was separated and identified by spectrum analysis including UV, IR and ESI-MS. the yield of red pigment and CysA was measured at different cultivation conditions, respectively. the internal relationship between the biosynthesis of red pigment and CysA was examined by adding the purified red pigment. [Results] The molecular formula of red pigment was confirmed as C15H10O5 which contains benzene ring and aromatic ring ketone structure and belongs to anthraquinones. The further experiments revealed that the negative relationship dominated in the biosynthesis between CysA and red pigment. The case with higher productivity of CysA due to valine feeding and high DO must be lower red pigment yield. Especially, the foreign red pigment added during the cultivation would result in down first and then up for CysA production. [Conclusion] The red pigment produced by Beauveria nivea was firstly separated and identified. Importantly, the research results verified that the red pigment and CysA had independent biosynthesis pathways which shared with the same substrate valine.

Abstract:[Objective] The possible immunomodulatory and anti-infectious effects of Lactobacillus acidophilus KLDS AD1 and Lactobacillus helveticus KLDS 1.8701 were evaluated on the intestinal mucosal immunity in the rats artificially infected with Escherichia coli O157:H7. [Methods] An model animal trial was carried out on rats divided into four treatments, challenged treatment with E. coli O157:H7 for seven days, artificially infected animals treated with L. acidophilus or L. helveticus for another seven days. The intestinal tissue was taken for assaying the secretory immunoglobulin A (SIgA) in intestinal fluid and cytokines (IL-2, IL-4, IL-6, IFN-γ) production in small intestinal tissue by ELISA. [Results] L. helveticus KLDS 1.8701 significantly attenuated the pathogenic influence of E. coli O157:H7 indicated by the high weight gain, better than L. acidophilus KLDS AD1. After treatment with E. coli O157:H7, the levels of SIgA, IL-2 and IFN-γ increased and reached to the maximum value at the third days, decreased at the fifth day, then IL-4 and IL-6 reached to the maximum value and decreased at the seventh day. The levels of SIgA and all assayed cytokines were significantly increased after oral administration of L. acidophilus KLDS AD1 and L. helveticus KLDS 1.8701 at eighth day, and remained higher level than control and pathogenic groups. [Conclusion] L. acidophilus KLDS AD1 and L. helveticus KLDS 1.8701 improved the intestinal mucosal immune by stimulating cytokines and SIgA production, and confered enhanced protection against E. coli O157:H7 infection.

Abstract:[Objective] The objectives were to investigate and discover some rare and important fungi from the soil in China. [Methods] The classical morphological characters and molecular systematics were used for identification of strains obtained. [Results] A strain of the genus Scedosporium was isolated from the soil of pig manure. The main characters were as follows: on Czapek agar, floccose, gray white to light brown. Conidiophore was single or branched; Single conidiophores was usually reduced to the conidiogenous cells, which is terminal or lateral, hyaline to subhyaline, smooth, cylindrical or lightly inflated flask-shaped, (3.5-45.0) μm×(1.5-3.0) μm; Conidia single, terminal or lateral, smooth, ellipsoidal, obovoid or sub-cylindral, (4.3-14.0) μm×(2.5-5.5) μm. [Conclusion] Based on the morphological characters and molecular systematic, the strain was proposed as S. aurantiacum Gilgado, Cano, Gené & Guarro, which is a new record species in China.

Abstract:[Objective] The rhizobacterium P. aeruginosa M18 can produce two antibiotics, pyoluteorin (Plt) and phenazine-1-carboxilic acid (PCA). The PqsR/PQS quorum sensing system consists of the response regulatory protein PqsR and the signaling molecule PQS. Previous studies have shown that the pqsR gene negatively controls Plt biosynthesis and its gene expression. This study aims to investigate the effect of PQS on Plt biosynthesis and its gene expression. [Methods] The pqsA gene was amplified from the M18 genome. A chromosomal pqsA inactivated mutant strain of M18 was constructed by the homologous recombination technique. Plt production assay and lacZ reporter analysis were utilized to assess the influence of PQS on Plt biosynthesis and its gene expression. [Results] In KMB media, Plt production of pqsA mutant was partially increased 1.53 times as much as that of M18 strain. The addition of PQS caused a certain degree of down-regulation of plt expression. [Conclusion] PQS partially down-regulates Plt biosynthesis and its gene expression in M18.

Abstract:Due to the fundamental physiology and current limits in detection methods, the majority of microorganisms, so-called “unseen majority (USM)”, in the natural world are not accessible using traditional microbiological tools. Small USM bacteria are dominant and have significant ecological functions in most aquatic environments, where nutrient concentrations are low. As they are sensitive to conventional high nutrient media and have small bio-volumes (less than 0.1 μm3), small bacteria often escape traditional cultivation attempts and are therefore still poorly described. In this review, the concepts relating to the characterization of small cells are compared. We also review the cultivation and detection methods and the distribution of small bacteria in aquatic environments, followed by in-depth discussion of the ecological functions of small bacteria. Finally, the future prospects of USM bacteria are discussed in terms of their growth physiology and applications in water quality evaluation.

Abstract:Vibrio parahaemolyticus, a gram-negative halophilic bacterium, first identified as a cause of food-borne illness in Japan in 1950, is widely disseminated in estuarine, marine, and coastal environments throughout the world. As one of major pathogens, V. parahaemolyticus can cause bacterial food poisoning and threaten the public health. V. parahaemolyticus isolates are multiple diverse genotype and serotypes faster adapting to the versatile environment. Molecular genetic analysis showed that the genetic diversity may be acquired as a result of gene recombination or horizontal gene transfer. This paper reviewed the finding, distribution, epidemiological characteristics and mutation molecular epidemiological characteristics of V. parahaemolyticus, particularly the global dissemination of pandemic serovar O3:K6 clone, so as to provide evidences for the traceability of the isolates.

Abstract:Soil properties depend not only on solid particle, liquid and gas in soil, but also on bacteria and fungus in soil. The mechanism of microorganism improving soil properties is that microorganism can change microstructure of soil by microorganism adsorption, inducing inorganic matter precipitation, bio-surfactant attachment and gas tamponade. Macro-performances of microorganism improving soil properties are mainly permeability reduction and strength improvement. Besides some achievements of theoretical analysis and experimental research on microorganism improving soil properties have been made, microorganism has also been applied well in some projects of sealing diaphragm and cementing reinforcement.

Abstract:Although antibiotics hold a leading position in the medical treatment and animal husbandry, but its prone-resistance to the pathogen lead to the rise of research and development of antimicrobial peptides (AMPs). As natural active substances, AMPs have antibacterial, antiviral, anti-tumor and immune regulation function, while the shortcomings such as short efficacy, sensitive to proteinase and high cytotoxicity limit its application. In this paper, the bottlenecks and their solution of antimicrobial peptide engineering were reviewed in terms of gene engineering, PEGylation, targeting and immobilization in order to promote the industrialization of AMPs.

Abstract:4-Hydroxybenzoate (4HBA) is a naturally occurring aromatic compound, and as a key intermediate metabolite not only for natural products but also for artificial products. There are four 4HBA metabolic pathways: protocacechuate cleavage pathway; catechol cleavage pathway; anaerobic degradation pathway in anaerobes; gentisate cleavage pathway. The last pathway including a NIH shift reaction remains to be elucidated. In this review we emphasized in NIH shift reaction involved in the 4HBA degradation. The key enzymes of each 4HBA metabolic pathway also be introduced. Finally, we described thermophilic Bacillus sp. B1 strain which was capable of degradation of various aromatic compounds including 4HBA, and presented a direction for NIH shift reaction research.

Abstract:Plant wilt is one of disease difficult control caused by Fusarium oxysporum in crop and vegetables production field. Here is a review about domestic and overseas studies on pathogenesis by F. oxysporum and the application of allelopathic. Co-pathogenesis caused by F. oxysporum secretion of toxins and cell wall degrading enzymes in host plants. The lineage-specific region is the reason of F. oxyspoyum with strongly virulent and widely host. Different genes associated with its disease mechanisms have been isolated respectively in specialized F. oxysporum strains. However, some plants and microorganism (Trichoderma spp., arbuscular mycorrhizal fungi, non-pathogenic F. oxysporum, and plant growth promoting rhizobacteria) release allelochemicals which directly inhibit the growth of F. oxysporum or active defense reaction of host plants. For the furthermore in future, genome sequencing will be essential for building accurate genetic maps of different pathotypes of F. oxysporum. And gene-gene relationships between F. oxysporum and the resistance host plant should be exploded. High-throughput technologies will be necessary at the level of transcriptome as well as at the proteome level. Screening new plant varieties for resistance blight will also be developed by molecular marker assisted breeding.

Abstract:This article introduces the reform and practice in environmental engineering microbiology experiment teaching, the quality of instruction is improved by constant reform and perfect in the course setting, teaching content, teaching methods, teaching means and assessment methods.

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Abstract:[Objective] Dolomite [CaMg(CO3)2], a carbonate mineral composed of calcium and magnesium carbonate is widely distributed both in terrestrial as well as in marine environments including petroleum reservoirs. It has been more than three centuries since dolomite was discovered for the first time. However the origin of dolomite remains unclear, which was referred to as “dolomite problem”. In 1990’s Vasconcelos C. from Swiss Institute of Technology proposed a model for “microbial dolomite formation”, which provided a new perspective on the origin of dolomite. However, this model is not yet optimized to fully clarify the relationship between dolomite formation, bacterial physiology and environmental parameters. The available published data on the dolomite formation mediated by microorganisms were performed at ambient temperature and pressure, which is different from the natural niche of dolomization. In this study, we introduced hydrostatic pressure as an additional environmental parameter in combination with the physiological status of bacteria in order to investigate the dolomite formation under multiple conditions. [Methods] Two strains, Lysinibacillus sphaericus and Sporosarcina psychrophila, which express urea hydrolysis activity, were used as biomass to mediate dolomite precipitation under different environmental conditions like temperature (15 °C and 30 °C), pressures (ambient and 20 MPa) and oxygen concentrations (aerobic and micro-aerobic). To determinate the morphology and component of carbonate precipitation, SEM (scanning electron microscope) combined with EDS (Energy Dispersive X-ray Spectrometry) analysis was performed. To determinate the mineralogy of carbonate precipitation, XRD (X-ray diffraction) analysis was performed. [Results] Both L. sphaericus and S. psychrophila were able to induce carbonate precipitation under all of the given experimental conditions. Both SEM and XRD results confirmed the irregular rhombohedral and spherical dolomite formation mediated by L. sphaericus at 30 °C under 20 MPa pressure and micro-aerobic condition. In addition to dolomite, other minerals (e.g. calcite, nesquehonite, huntite) were also detected to be present in precipitation. [Conclusion] This study has demonstrated that both L. sphaericus and S. psychrophila are able to mediate carbonate precipitation. Especially L. sphaericus is proven to induce dolomite formation under certain conditions. Dolomite formation is significantly influenced by urea hydrolysis activity, temperature and pressure. Our results provide evidence to explain the origin of dolomite from deep sphere and help to optimize the model of “microbial dolomite formation”.

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