Abstract:[Objective] In order to improve the acetoin production efficiency by Bacillus subtilis CCTCC M 208157. [Methods] The processes of acetoin fermentation were investigated under various pH conditions in a 7 L fermentor. [Results] The effects of pH on cell growth and acetoin production showed that the optimum pH for acetoin production and cell growth were 4.5 and 5.5, respectively. Based on the above results, a two-stage pH control strategy was developed: the pH was controlled at 5.5 for the first 16 h, and then decreased to 4.5 for the remaining time. [Conclusion] With this optimized pH control strategy, the production of acetoin had a significant improvement. Moreover, the production, conversion rate from glucose and productivity of acetoin were achieved at 32.7 g/L, 0.41 g/g and 0.91 g/(L·h), respectively, which were 41%, 42% and 69% higher than that from the strategy without pH control.

Abstract:[Objective] To screen a psychrotolerant cellulase-producing strain from the decayed soil of Huanglong Mountain, Sichuan, China, and determine the properties of the cellulase. [Methods] The strain was identified by the morphology and ITS sequence analysis. The DNS method was used to determine the activity of cellulases. [Results] A psychrotolerant cellulase-producing strain HD1031 was screened from the decayed soil of Huanglong Mountain. It was identified as Pseudogymnoascus roseus by the morphology and ITS sequence analysis. The strain could grow between 4 °C and 25 °C and its optimum growth temperature is 16 °C?17 °C. In the medium containing Avicel, corn cob powder, (NH4)2SO4 and Tryptone, the strain HD1031 produced cellulases. After cultivating under the conditions of 17 °C and 160 r/min for 8 days, the cellulases activities in the fermentation broth were CMCase activity 366.67 U/mL, FPA 87.6 U/mL and the β-glucosidase activity 90.8 U/mL. The optimum pH value and temperature of the CMCase was pH 6.0 and 50 °C, respectively. [Conclusion] A psychrotolerant cellulase-producing strain HD1031 was screened and identified. The cellulase possessed the characters of cold-active cellulase.

Abstract:[Objective] To investigate the diversity of cultivable bacteria isolated from Crassostrea hongkongensis collected from the tidal flat of Naozhou Island (20°52′–20°56′ N, 110°33′–110°38′ E) in the South China Sea. [Methods] Bacteria strains were isolated from homogenates of the sample by using conventional culture-dependent method, and then the isolated strains were investigated by using a phylogenetic analysis based on the 16S rRNA gene sequences. [Results] We isolated 102 bacteria strains from the sample on a number of media [MA (marine agar 2216), MH (moderate halophilic medium agar), NA (nutrient agar)] supplemented with 0–25% (W/V) NaCl. On the basis of the results of some morphological, physiological and biochemical tests, we selected 74 strains to perform a further phylogenetic analysis. Our results showed that the 74 isolates represented 38 species, belonging to 18 genera (Idiomarina, Morganella, Proteus, Halomonas, Paracoccus, Wohlfahrtiimonas, Marinobacter, Vibrio, Pseudoalteromonas, Shewanella, Oceanimonas, Nitratireductor, Myroides, Bacillus, Virgibacillus, Staphylococcus, Enterococcus, Trichococcus) of 16 families (Idiomarinaceae, Enterobacteriaceae, Halomonadaceae, Rhodobacteraceae, Xanthomonadaceae, Alteromonada- ceae, Vibrionaceae, Pseudoalteromonadaceae, Shewanellaceae, Aeromonadaceae, Phyllobacteriaceae, Flavobacteriaceae, Bacillaceae, Staphylococcaceae, Enterococcaceae, Carnobacteriaceae) in 4 phylogenetic groups (Gamma-Proteobacteria, Alpha-Proteobacteria, Bacteroidetes, Firmicutes). The most of isolates were within the subphylum Gamma-Proteobacteria (45 strains, 60.8%), followed by Firmicutes (12 strains, 16.2%), Bacteriodetes (11 strains, 14.9%) and Alpha-Proteobacteria (6 strains, 8.1%). The phylogenetic analysis results suggested that there were obvious genetic divergences between most isolates and their closest type strains (16S rRNA gene sequence similarities ranged from 94.3% to 99.8%). The results also showed that, out of the 74 isolates, at least 6 strains could represent potential new taxa. Strain JSM 111069 could represent a novel genus in the family Carnobacteriaceae. Strains JSM 111039 and JSM 111085 could represent two novel species of the genus Bacillus, and strains JSM 111020, JSM 111072 and JSM 111090 could represent three novel species within three characterized genera Pseudoalteromonas, Proteus and Idiomarina, respectively. [Conclusion] The results presented above showed that there are abundant bacteria diversity in Crassostrea hongkongensis collected from the tidal flat of Naozhou Island in the South China Sea.

Abstract:[Objective] To identify marine fungus HN4-13 isolated from Lianyungang coastal sea sediments with antibacterial activity and to optimize the fermentation conditions of synthesizing antibacterial active substances. [Methods] Strain HN4-13 was identified based on its morphological characters and internal transcribed spacer (ITS) sequence; The optimization of fermentation conditions for antibacterial production by strain HN4-13 were investigated by the one-factor-at-a-time method and the orthogonal design method. [Results] Strain HN4-13 was identified as Aspergillus flavipes, and the optimal fermentation conditions can be recognized as follows: 4% sucrose, 0.5% peptone, 0.1% KCl, 0.06% NaH2PO4, 1% inoculation concentration, 28 °C, 160 r/min for 9 days. [Conclusion] The results provide the clues for further separation and purification of the antibacterial active metabolites derived from strain HN4-13.

Abstract:[Objective] The purpose was to study azo reduction activity in the strain Aeromonas hydrophila HS01 under anaerobic conditions. [Methods] We established the anaerobic system of HS01/electron donor/azo dye to investigate the ability of strain HS01 to obtain energy for growth by coupling the oxidation of electron donors to azo reduction, and further explore the enhanced azo microbial reduction by the presence of Fe(III) oxides. [Results] Within 30 h, HS01 could reduce 0.45 mmol/L orange I at the expense of 4.35 mmol/L glucose, and the active cells increased by 27 times in the treatments of HS01/glucose/orange I. The decolorization rate of orange I reached 87%, 85%, 88%, and 90%, respectively, when citrate, glycerol, sucrose or glucose served as the electron donor. It showed different decolorization rate by pH of 5?10 and 0.5?5.0 mmol/L of initial concentrations of orange I. In the system of HS01/glucose/orange with α-FeOOH, decolorization rate increased from 90% to 95%. [Conclusion] HS01 was capable of anaerobic respiration on orange I as the sole terminal electron acceptor with glucose as the electron donor. The decolorization rate depended on the types of electron donor, pH and initial concentrations of azo: citrate, glycerol, sucrose or glucose could serve as an effective electron donor for dissimilatory azo reduction, whereas formate, acetate, propionate, lactate and ethanol do the opposite; pH of 6.0?8.0 was optimum for azo reduction by HS01. Dissimilatory Fe(III) reduction and azo reduction by strain HS01 occurred simultaneously, and the presence of Fe(III) oxides would enhance orange I decolorization.

Abstract:[Objective] This study was to find the T-2 toxin-degrading strains, which were isolated and identified from natural environment. [Methods] Fusarium producing T-2 toxin were isolated from the samples of shrimp culture pond water, pond sediment and shrimp mixed feed, respectively. When it was cultured in GYM medium for 14 days, the airborne bacteria in nature environment were inoculated. The content of T-2 toxin was detected by LC-MS/MS at 28 day in its cultivation. T-2 toxin-degrading strains were screened from the bacteria suspension in which the content of T-2 toxin has obviously decreased with dilution spread method, plat streaking method, Gram stain method and microscopic examination. And then the identification and phylogenetic analysis of the screened strains were performed by 16S rRNA method. The method was also used to validate the toxin-degrading capacities of the screened strains respectively and the combined effect of them in different matrixes. [Results] Two T-2 toxin-degrading strains were screened out during the cultivation of five Fusarium strains which were isolated as indicator bacteria from shrimp culture environment. The results of 16S rRNA analysis showed that they were Pseudomonas geniculate and Staphylococcus nepalensis, and their degradation rates to T-2 toxin were 90.9% and 85.5% respectively. But there was no significant difference between the degradation effects of the two strains (P>0.05). In addition, the combined effect was good but had no significant difference with the single strain’s degradation effect (P>0.05). And the combined degradation effects were not much affected by different matrixes (P>0.05). [Conclusion] This new discovery established a basis for further ascertaining T-2 toxin degrading genes and developing T-2 toxin degrading enzymes.

Abstract:[Objective] In order to investigate the diversity of crude oil-degrading bacteria in the seawater, mud and sponge samples from Dalian Bay, and obtain new oil-degrading bacteria. [Methods] Crude oil was used as sole carbon source to enrich and isolate the potential oil-degrading bacteria from samples of seawater, mud or sponge. Phylogenetic analysis was conducted by 16S rRNA gene sequences of the bacteria. [Results] After screening via morphological and 16S rRNA gene sequences analysis 50 strains belonging to 22 genera were obtained. Among them, 6 strains shared 16S rRNA gene sequence identities of 95%?97% with the most similar strains, were speculated new species. Further experiments revealed oil-degrading capability of 45 strains. [Conclusion] This study demonstrated a high diversity of the cultivable oil-degrading bacteria in Dalian Bay, and obtained new resources in bioremediation of marine oil pollution.

Abstract:[Objective] To isolate the aerobic strain with high-efficiency in degrading decabromodiphenyl ether (BDE-209) from sediment samples collected from Guiyu town in Guangdong Province, an e-waste recycling area, and investigate its degradation characteristics. [Methods] The strain was identified based on its physio-biochemical characteristics and 16S rRNA sequence analysis. The orthogonal experiment was conducted to determine the optimal degrading conditions, effects of different degradation systems and other factors on the degradation efficiency of the strain. [Results] The strain was identified as Brevibacillus brevis named as GY2. Its five-day degradation efficiency reached 54.38% when the initial concentration of BDE-209 was 1 mg/L. The optimum conditions for BDE-209 degradation were as follows: pH 7, bacterial dosage 3 g/L, and culturing temperature 30 °C. The study also showed that the optimal strain age was 36 h and the best nitrogen source was (NH4)2SO4. B. brevis could tolerate the toxicity of Cu2+ and Cd2+, although the presence of these heavy metals posed certain influence on BDE-209 degradation. As the concentration of Cu2+ and Cd2+ were in the range of 1?5 mg/L and 0.3?0.5 mg/L, respectively, the degradation efficiency of BDE-209 was still over 50%. [Conclusion] B. brevis is effective in degrading BDE-209, the results are of significance and application importance in the study of aerobic microbial degradation and environment bioremediation of BDE-209.

Abstract:[Objective] Carposina niponensis Walsingham is an important pest in Chinese orchard and causes wide host and area damage. Artificial feeding of C. niponensis is the basis of research and integrated control, meanwhile Beauveria bassiana is a main pathogen to overwintering larvae C. niponensis and brings great difficulties to establish laboratory population. So our objectives is to screen fungicides which have good inhibition effect to control B. bassiana in large-scale feeding C. niponensis. [Methods] Liquid shaker shock method and plates cross bracketing method were used to evaluate the effect of 16 common fungicides on spore germination and hyphal growth of B. bassiana. [Results] We screened 9 fungicides which had good inhibitory effect on B. bassiana, in which Procymidone and Zhongshengmycin were good at spore germination inhibitory, and inhibitory rate were 97.88%±1.53% and 93.22%±2.36% at recommended concentration. While, Imazalil and Tebuconazole have obvious inhibition effect on hyphal growth, and inhibitory rates were 100.00%±0.00% and 98.43%±0.99%. But 5 fungicides (Prochloraz, Propiconazole, Thiabendazole, Myclobutanil, Pyraclostrobin) had good effect on both spore germination and hyphal growth. In addition, we evaluated mortality of C. niponensis at different concentrations (recommend concentration, 5-fold recommend concentrations, 10-fold recommend concentration) to investigate negative impact of 9 fungicides on C. niponensis Walsingham, The results showed that 5 fungicides have slightly adverse impact on C. niponensis. [Conclusion] Zhongshengmycin, Tebuconazole, Pyraclostrobin and Thiabendazole can be used to control B. bassiana infection in large-scale feeding C. niponensis.

Abstract:[Objective] The aim of this study is to analyse membrane lipids composition of a rhizobial strain isolated from nodule of Alfalfa in Heilongjiang province under phosphorus-limited condition and to clone and identify the genes required for diacylglyceryl trimethylhomoserine (DGTS) biosynthesis. [Methods] The rhizobial strain was cultured in Sherwood minimal medium containing either normal or low concentrations of inorganic phosphate.The membrane lipids were extracted by Bligh-Dyer method and were analysed by thin-layer chromatography (TLC) using both the lipids of Sinorhizobium meliloti 1021 and standard samples of some phospholipid as a reference. PCR primers was designed according to the sequences of btaA and btaB in the GenBank. The PCR-amplified btaA and btaB genes were expressed in Escherichia coli BL21(DE3). The gene function was verified by testing DGTS production. 16S rRNA gene sequences of the strain 17560 was analysed. [Results] The strain 17560 isolated from Alfalfa in Heilongjiang province shares 99.8% 16S rRNA gene sequence identity with Sinorhizobium meliloti. But its lipid compositions were quite different from that of the reference strain S. meliloti 1021. Under phosphorus-limited conditions, the main membrane lipids of the strain17560 were phosphorus-free lipids, such as ornithine lipid (OL) and DGTS. Strain 17560 contain three different types of OLs meanwhile S. meliloti 1021 contain only one type of OL. Under normal phosphorus condition, the main membrane lipids of strain 17560 were phospholipid, such as phosphatidylethanolamine (PE) and one unkonw amino-containing phospholipid, while the main membrane lipids of S. meliloti 1021 are PE, phosphatidylcholine (PC) and phosphatidylglycerol (PG). BtaA and btaB genes of strain 17560 were amplified. One PCR product of 1 913 bp was obtained, which contains two ORFs sharing 99% sequence identity with btaA and btaB genes of S. meliloti 1021 respectively. This DNA fragment was cloned to pET-30a(+) vector and transferred to E. coli BL21(DE3). The proteins of 45 kD and 25 kD were detected, and TLC analysis further revealed DGTS production in the expression strain when induced with isopropyl-b-D-thiogalactoside (IPTG). [Conclusion] Membrane lipids of rhizobial strains from Alfalfa could be quite different although their phylogenetic position were the same. Membrane lipids of rhizobial strain varies with the phosphorus content in the growth medium, the main membrane lipids of the strain were phosphorus-free lipids, such as OL and DGTS under phosphorus-limiting condition. One unknown amino-containing phospholipid and three different types of OLs was found in Sinorhizobium. The btaA and btaB genes were cloned and expressed successfully in E. coli.

Abstract:[Objective] The role mechanism of tachyplesin I on Escherichia coli was investigated to provide potential novel antibacterial drugs for treating disease caused by enteropathogenic bacteria. [Methods] Antimicrobial activity for tachyplesin I for Escherichia coli was determined using Oxford cup and micro-broth dilution methods. The combination, distribution and killing process of tachyplesin I against Escherichia coli were observed under laser confocal scanning microscopy. Ultrastructure of tachyplesin I against Escherichia coli was observed under transmission electron microscope. The genomic DNA and RNA binding ability of tachyplesin I was examined by agarose gel retardation electrophoresis in this experiment. [Results] The minimum inhibitory concentration and minimum bactericidal concentration was 5, 20 mg/L, respectively. The results of laser confocal scanning microscopy and transmission electron microscope indicated that tachyplesin I penetrated the cell membrane of Escherichia coli and accumulated in the cytoplasm immediately after being added to the cells. Later, mem- brane damage and cellular content outflow was seen. And tachyplesin I had effect on genomic DNA in a concentration-dependent manner. The low concentrations of tachypesin I (10 mg/L) had no obvious effect on DNA, while the high concentrations of tachypesin I (above or equal to 80 mg/L) could lead to break in genomic DNA. Tachypesin I could combine with genomic DNA and RNA. [Conclusion] The results provide a theoretical basis to further understand sterilization mechanism of tachyplesin I at molecular level.

Abstract:[Objective] Fructophilicity of wine yeasts is critically important for the maintenance of a high fermentation rate at the end of alcoholic fermentation. [Methods] In this study three Saccharomyces cerevisiae strains with different fermentation traits were investigated in synthetic grape medium to determine the relationship between their relative abilities to utilise glucose and fructose and fermentation performances. [Results] Parameters obtained by calculating from kinetic glucose and fructose fermentation curve, include fermentation duration, fructose concentration if glucose concentration was 0, area difference under fructose and glucose curve. The latter two parameters can rank their fructophilicity significantly. [Conclusion] This study provides an effective and objective method for programs which seek to generate strains that have a high fructose utilization capacity in wine fermentation.

Abstract:[Objective] The objective of this study was to increase the yield of 10-deacetylbaccatin III (10-DAB) and taxol in Cladosporium cladosporioides MD2 through optimizing fermentation conditions. [Methods] The culture conditions of C. cladosporioides MD2 were optimized by single factor experiments to investigate the effect of different initial pH values of medium, culture temperatures, rotational speeds, and culture time on the yield of 10-DAB and taxol. The fermentation medium components were optimized by single factor and orthogonal experiments to investigate the effect of four precursors on the yield of 10-DAB and taxol. [Results] The optimization results were that 1 mL spore suspension of C. cladosporioides MD2 (107?108 spores) was inoculated into 300 mL YES medium with the initial pH of 5.0, which was supplemented with 15 mg/L sodium benzoate, 25 mg/L L-phenylalanine, 5 mg/L serine and 15 mg/L glycine, and then cultured at 28.0 °C and 220 r/min for 12 days. Under the optimized fermentation conditions, the biomass, 10-DAB yield and taxol yield of C. cladosporioides MD2 were respectively 15.5 g/L, 471.5 μg/L and 569.5 μg/L, about 1.3 times, 3.6 times and 3.4 times of that under the initial fermentation conditions. [Conclusion] A suitable fermentation condition of C. cladosporioides MD2 for 10-DAB and taxol production in flask culture was obtained for the first time, and these results provided a reference for its scale-up fermentation.

Abstract:[Objective] Fosmid library of cultured human dental plaque samples was constructed and screened for antibiotic resistance genes. [Methods] Dental plaques from 20 individuals were obtained and cultured anaerobically in vitro. Bacteria DNA was extracted and Fosmid library was constructed. Antibiotic resistant clones were selected by plating on LB agar containing one of the three antibiotics: kanamycin, tetracycline, and ampicillin. Inserts conferring resistance were sequenced and annotated. [Results] A metagenomic Fosmid library was generated, which contained approximately 18 480 clones. Three antibiotic resistance genes were obtained through functional screening, including one kanamycin resistance gene encoding bifunctional aminoglycoside modifying enzyme AacA-AphD, one tetracycline resistance gene tet (M) and one ampicillin resistance gene encoding class C beta-lactamase. [Conclusion] It turns out that it is possible to construct fosmid libraries using cultivated dental plaque samples to screen antibiotic resistance genes.

Abstract:[Objective] CaFTH1 gene encodes a putative iron permease in Candida albicans. To investigate the role of CaFTH1 in cellular iron metabolism and vacuolar function, we constructed fth1?/? single gene deletion and fth1?/?fet33?/? double deletion mutants. [Methods] Sequence alignment and analysis were performed by the relevant bioinformatic software. Effect of iron avaibility on the expression of CaFTH1 was conducted by real-time PCR. We constructed the fth1?/? and fth1?/?fet33?/? mutants by PCR-mediated gene disruption. We monitored the change of cellular iron content of the mutants by using atomic absorption spectroscopy (AAS), and explored the growth status under iron-limited and hyphal-inducing conditions. Furthermore, we also investigated the effect of gene deletions on vacuolar function by metabolic shift experiment. [Results] Sequence alignment revealed that C. albicans CaFth1 protein is a member of Ftr1 iron permease superfamily, with the highest homology with S. cerevisiae vacuolar membrane proteins ScFth1. Iron starvation induced the expression of CaFTH1, while iron repletion decreased its mRNA levels. Deletion of CaFTH1 resulted in decreased cellular iron content, and deletion of CaFET33 on the basis of fth1?/? mutant further decreased cellular iron content. For the metabolic shift experiment, the fth1?/?fet33?/? mutant also exhibited growth defect under iron-limited conditions. In addition, the fth1?/?fet33?/? mutant showed distinct wrinkled colonies in some solid hyphal-inducing conditions, while the fth1?/?fet33?/? mutant displayed increased aggregation ability in the presence of liquid-inducing cues. [Conclusion] CaFTH1 is induced in response to iron limitation, and plays an important role in maintaining C. albicans cellular iron homoeostasis and vacuolar function. Double deletion of CaFTH1 and CaFET33 genes affects the colonial morphology and hyphal aggregation.

Abstract:[Objective] To explore the mechanism of signaling pathways Streptococcus suis serotype 2 infected monocytes/macrophages leaded, discuss the role of capsular sialic acid component played in Streptococcus suis activate macrophage TLR2-AKT-NF-κB signaling pathway. [Methods] RAW264.7 as the target cell line, RT-PCR, Western blotting, immunofluorescence and ELISA were applied to detect different infection time of wild type strain, sialic acid knockout strain and sialic acid complementary strain on macrophages TLR2 mRNA transcription level, AKT phosphorylation level, NF-κB activation level, as well as TNF-α secretion level. Pretreat with TLR2 blocking agent and PI-3K inhibitor on macrophages, detect the expression level above. [Results] Sialic acid knockout strain activates signal transduction pathways selectively. RT-PCR results show that TLR2 mRNA expression levels began to increase at 1 h, 1.5 h reached its peak then slowly decline. Western blotting showed that TLR2 protein expression level reached its peak at 7 h, 9 h decline. Level of p-AKT is stable at its peak during 1.5?5 h, 7 h decline. Immuno fluorescence showed high level of NF-κB activation-nuclear translocation at 15 min. ELISA results indicate TNF-α secretion level was significantly higher than the other two strains after 10 h. TLR2 blocking agent and PI-3K inhibitor significantly suppressed the activation degree of three strains. [Conclusion] Capsular sialic acid could inhibit activation of the TLR2-AKT-NF-κB signaling pathway to some extent, thus participate in bacteria evading the host immune defense.

Abstract:[Objective] To identify the marine bacteria SSQ500 with antitumor activity, and to study the antitumor mechanism of fermentation products. [Methods] The strain SSQ500 was identified using its morphological characteristics, physiological, biochemical properties and 16S rDNA gene sequence. The tumor cell was collected after different concentration activity compounds acted on difference time. The inverse proportion of apoptosis of the liver cancer cell SMMC-7721 was analyzed by flow cytometry. To study the protein expression by examine Caspase3, Caspase8. [Results] The strain SSQ500 was identified belong to Myxococcaceae sp.. The activity compound SSQ produced by this bacteria can induce SMMC-7721 cell to apoptosis by up-regulate the expressions of Caspase3, Caspase8. [Conclusion] The SSQ500 belongs to Myxococcaceae sp., and the fermentation product of this bacteria can induce tumor cell to apoptosis. That may be related to up-regulate the expressions of Caspase3, Caspase8.

Abstract:[Objective] To use the self-designed ELP[I]50 as the non-chromatographic purification tag, the recombinant Trx was purified, and the inverse temperature transition (Tt) of ELP[I]50-Trx influenced by PEG was investigated. [Methods] The Trx gene was synthesised, and was subcloned into the modified pET28-ELP expression vector, and the expression vector was transformed into BLR(DE3). The fusion protein was expressed and purified via inverse transition cycling (ITC), then the Tt was tested under different concentration of PEG. [Results] ELP[I]50-Trx fusion protein was successfully expressed and purifid via ITC, Tt was 28.6 °C when ELP[I]50-Trx is 25 μmol/L; the Tt was reduced down to 22.3 °C, 15.9 °C, 6 °C and 0 °C when PEG concentrations is 5%, 10%, 15%, 20% respective. [Conclusion] The ELP[I]50 can perform as an efficient recombinate protein purification tag to scale up at low cost and easy to use, and PEG can reduce protein Tt to enhance the purification efficiency for enlarging the range of application. ELP could be applied to a variety of recombinant proteins purification.

Abstract:[Objective] To characterize the molecular characteristics of hemagglutinin (HA) of influenza B viruses isolated in Nanjing in 2011. [Methods] We chose 7 strains representative influenza B virus in different epidemic time in 2011. In order to monitor evolution; of the virus, then we carried out HA sequencing, and analyzing the genetic characteristics of HA with the bioinformatics method. [Results] Of the 7 randomly selected Inf-B strains, 4 strains were Victoria lineage strains, and 3 strains belong to Yamagata lineage. Comparison of nucleotide and amino acid sequences of HA gene with the correspondent vaccine strains, we find changes at antigenic sites 146 and 197 of Victoria lineage strains, and 116 and 198 of Yamagata lineage strains as well. 197/198 receptor-binding sites belong to Victoria/Yamagata lineage strains correspondently. As the result, 197/196 sites in Victoria/Yamagata isolates virus added an potential glycosylatio site. [Conclusion] Both B/Victoria and B/Yamagata lineage viruses co-circulated in Nanjing, the further researches of the changes at 197/198 sites of HA1 gene of Victoria/Yamagata isolates virus are valuable worthy.

Abstract:Vanillin is one of the most important flavoring compounds, and it is widely used in the food industry, spice fragrance, and medicine industry, etc. The annual worldwide consumption is estimated over 16 000 tons. Due to people’s increasing concern for natural food, the production of natural vanillin has become the major point of scientific research. By comparing different production methods of vanillin, we concluded that the microbial transformation to vanillin is the most promising method. Research developments on different biosynthetic pathways for vanillin, as well as the genes and enzymes involved, were discussed. In addition, the advantages and disadvantages of each pathway were compared and explained. Finally, the existing bottlenecks in biosynthesis of high-yield natural vanillin with the help of genetic and metabolic engineering, and the potential development direction in this field were elucidated.

Abstract:[Objective] In order to simplify the procedure and improve the sensitivity of biological toxicity testing method, the lyophilised MTOXPlate based on 11 genetically diverse microorganisms was prepared. [Methods] The tested microbial strains were fixed on the microplate by the vacuum freeze-drying method. Fluorescence spectrophotometry was used to determine the effects of several cryoprotectants on the freeze dried strains with the survival rate as the selecting index. The test condition was optimized through the sensitivity of toxicity detection. [Results] When the protective agent contains 8% trehalose, 2% glucose, 2% mannitol and 1% sodium glutamate, the mean cell survival rate can reach 89.41% for 11 microbial strains used in this study. The resurrection medium and test sample were added to each well of the pre-prepared 96-well microplate at the same time. So that, short testing time and optimal detection sensitivity could be obtained. This lyophilised MTOXPlate exhibits high sensitivity and good reproducibility, which is suitable for the toxicity assessment. [Conclusion] MTOXPlate could be a new biological toxicity test technology, which can be applied to the field of ecological toxicity testing.

Abstract:

Abstract:[Objective] This study focus on the diversity of culturable thermophilic actinobacteria isolated from Dong Chuan dry hot river valley, Yuan Mou soil forests, and some high-temperature composts, hot springs nearby Kunming in Yunnan province, and exploring their cellulase producing activity. [Methods] Over five hundreds strains were isolated by the plate dilution method. After dereplication and removing the similar strains based on colony-characteristics, more than three hundreds strains were sequenced for further research. The cellulase producing activity of 451 strains were further detected by Congo red solution. [Results] BLAST analysis of the partial 16S rRNA gene sequences revealed that these strains have the highest similarity with 33 described genera, which were distributed in 15 families of 9 suborders. Among of them, five actinobacterial strains were selected as potential candidates for further polyphasic taxonomic research, based on the lower similarities of 16S rRNA gene sequences. Cellulase screening results showed that the positive rate was about 57% in total 451 strains. Most of them were distributed in three genera of Streptomyces, Micromonospora and Nonomuraea. [Conclusion] There are considerable diversity of culturable thermophilic actinobacteria in dry hot environments of Yunnan province. Meanwhile, these strains exhibited higher positive rate and stronger activity of cellulase, which will provide high-quality experimental materials for future research.

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