Ultrasound-assisted extraction of polysaccharides from Artemisia selengensis Turcz and its antioxidant and anticancer activities.

Artemisia selengensis Turcz (AST) is a perennial herb with therapeutic and economic applications in China. The effects of ultrasound-assisted extraction (UAE) parameters upon extraction yield (EY%), antioxidant and antitumor activities of the polysaccharides extracts were studied by using a factorial design and response surface methodology. The optimal conditions determined were as: ultrasonic power 146 W, extraction time 14.5 min. and extraction temperature 60 °C. The average molecular weights of two homogeneous polysaccharides (APS1 and APS2) purified by DEAE cellulose-52 and Sephadex G-100 column chromatography were 125.4 and 184.1 kDa, respectively. Monosaccharide analysis showed that APS1 and APS2 were composed of five common monomers i.e., galactose, mannose, arabinose, xylose and rhamnose and one different monomer glucose and galacturonic acid respectively, with a most abundant part in molar % of APS1 and APS2 were glucose (83.01 %) and galacturonic acid (48.87 %) while least were xylose (0.80 %) and mannose (1.73 %) respectively. The antioxidant properties were determined by evaluating DPPH, hydroxyl radical scavenging activity and reducing power which indicated both APS1 and APS2 showed strong scavenging activities and anticancer activities on HT-29, BGC823 and antitumor activity on HepG-2. As UAE improved the polysaccharides yield than CSE, meanwhile, no significant difference of polysaccharides chemical compositions. Therefore, the present study suggests that the consumption of AST leaves may beneficial for the treatment of many diseases.

Synthesis and characterisation of galactosyl glycerol by ß-galactosidase catalysed reverse hydrolysis of galactose and glycerol.

A study of an enzymatic method for the production of galactosylglycerol is described. The effects of enzyme sources, enzyme amount, reaction temperature, reaction time, substrate ratio of glycerol to galactose, buffer content and pH on galactosylglycerol yield (mg/ml) were investigated. Under the optimum reaction conditions of ß-galactosidases from Kluyveromyces lactis 240 U/ml, temperature 40 °C, time 24 h, buffer amount 60% (percent volume of buffer to that of substrates, pH 6.5), and the substrate molar ratio of 10 (glycerol16 mmol:galactose 1.6 mmol), the yield of galactosylglycerol was up to 116.47 mg/ml (galactose conversion 55.88%). The product was purified by activated charcoal and Sephadex G-15 column chromatography, up to 96%. The purified galactosylglycerol was fully characterised by MS and NMR, and identified as a mixture of (2R)- and (2S)- 3-O-ß-D-galactopyranosyl-glycerol.

Antifungal activity and mechanism of fengycin in the presence and absence of commercial surfactin against Rhizopus stolonifer.

The antifungal activity and mechanism of fengycin in the presence and absence of commercial surfactin against Rhizopus stolonifer were investigated. The MIC (minimal inhibitory concentration) of fengycin without commercial surfactin added was 0.4 mg/ml while the MIC of fengycin with commercial surfactin added was 2.0 mg/ml. Fengycin acted on cell membrane and cellular organs and inhibited DNA synthesis. The antifungal effect of fengycin was reduced after commercial surfactin was added. All these results suggest that the fungal cell membrane may be the primary target of fengycin action and commercial surfactin may reduce the antifungal activity of fengycin.

Downregulation of ornithine decarboxylase by pcDNA-ODCr inhibits gastric cancer cell growth in vitro.

Ornithine decarboxylase (ODC), the first rate-limiting enzyme of polyamine biosynthesis, was found to be associated with cell growth, proliferation and transformation. ODC gene expression in gastric cancer was increased and its level was positively correlated with the degree of malignity of gastric mucosa and development of gastric lesions. In order to evaluate the therapeutic effects of antisense RNA of ODC on gastric cancer, an antisense RNA of ODC expressing plasmid pcDNA-ODCr which delivered a 120 bp fragment complementary to the initiation codon of ODC gene was constructed and transfected to gastric cancer cells SGC7901 and MGC803. Expression of ODC in gastric cancer cells was determined by western blot. Cell proliferation was assessed by MTS assay. Cell cycle was analyzed by flow cytometry and Matrigel assay was performed to assess the ability of gastric cancer cell invasiveness. The results showed that the ODC gene expression in gastric cancer cells transfected with the pcDNA-ODCr was downregulated efficiently. Tumor cell proliferation was suppressed significantly, and cell cycle was arrested at G1 phase. Gastric cancer cells had reduced invasiveness after gene transfer. Our study suggested that antisense RNA of ODC expressing plasmid pcDNA-ODCr had antitumor activity by inhibiting the expression of ODC, and downregulation of ODC expression using a gene therapy approach might be a novel therapeutic strategy for gastric cancer.

[Antibacterial activity and property of the fermentation product of marine Streptomyces sp. GB-2].

Marine Streptomyces GB-2, isolated from marine samples collected in the intel tidal zone of Lianyungang, was found to produce antibacterial substance which exhibited significant inhibitory effects on 11 Gram-positive bacteria and 4 Gram-negative bacteria. The antibacterial substance was proved to be neutral and water-soluble according to paper chromatogram analysis, and its production was significantly associated with aritificial seawater. The stability analysis of the fermentation broth of Streptomyces GB-2 showed that it was very stable at pH1 and pH12 under 121 degrees C and changed very little under ultraviolet treatment. The substance produced by strain GB-2 exhibited potential use in the areas of bio-control, food and medical application.

[Isolation and identification of lipopeptides produced by Bacillus subtilis fmbJ].

Isolation and idenfication of lipopeptides from Bacillus subtilis fmbJ was carried out in this paper. With HPLC method, it was determined that the antimicrobial substance was composed of many components, and one of them had the similar retention time similar to surfactin. In addition, the antimicrobial substance was proved to include the closed cycle peptide bind by TLC, and one of them had the migrating rate similar to surfactin. Furthermore, ESI-MS analysis showed that the antimicrobial substance contained five homologues of fengycin, such as m/z1449.9, m/zl1463.8, m/zl1477.8, m/z1491.9 and m/z1505.9, and three homologues of surfactin, such as m/z1008.8, m/z1022.8 and m/z1036.8.

[Inhibitory effect of new antimicrobial substance by Bacillus subtilis fmbJ on Newcastle disease virus and infectious Bursal disease virus in vitro].

The resistance effect on Newcastle disease virus (NDV) and Infectious Bursal Disease Virus(IBDV) in vitro of a new antimicrobial substance (AS), which produced by a Bacillus subtilis strain named B. subtilis fmbJ. Results showed that the TD50 and TD0 value of this AS on Chicken Embryo Fibroblasts cell (CEF) were 128.95mg/L and 25.79mg/L, respectively. This AS could strongly inhibit the cytopathic effects of cell induced by NDV as well as IBDV, and increase the survival rate of cell remarkably. This AS could inhibit the function of NDV and IBDV, and it could defend against the infection and inhibit multiplication of NDV and IBDV, and the effect was the same as the antiviral medicine Ribavirin. It had lower toxicity to CEF cell, therefore we would study it further that it was as antiviral medicine.

[Media optimization for the novel antimicrobial peptide by Bacillus sp. fmbJ224].

The novel antimicrobial peptide in submerged fermentation by Bacillus sp. fmbJ224 is strongly influenced by many internal and external factors, namely medium constituents and fermentation conditions. In this study, Plackett-Burman design was undertaken to evaluate the effects of the seventeen factors. By the statistical regression analysis, the significant factors affecting the novel antimicrobial peptide in submerged fermentation by Bacillus sp. fmbJ224 were determined as follows: glucose, NH4NO3, glutamic acid, CaCl2, MnSO4. In the second phase of the optimization process, a response surface methodology (RSM) was used to optimize the above critical internal factors, and to find out the optimization concentraction levels and the relationships between these factors. By solving the quadratic regression model equation using appropriate statistic methods, the optimal concentration of the variables were determined as: 8.13 g/L glucose, 6.14 g/L NH4NO3, 4.2 g/L glutamic acid, 3.98 mg/L CaCl2, 4.87 mg/L MnSO4. The content of the novel antimicrobial peptide was increased from 1304.21 microg/mL to 1487.58 microg/mL. The experimental data under various conditions have validated the theoretical values.

[Production of functional lipids by lipase-catalyzed acidolysis of lard in solvent free system].

China has richly and inexpensive fat and oils from animal and plants, but these resources could not get effectively utilization. In order to make the best of these resources, lipase-catalyzed acidolysis of lard with caprylic acid to produce functional lipid in solvent free system was investigated. Of the five lipases that were tested in the initial screening, immobilized lipase TL IM fromca T. languginosa resulted in the highest incorporation of capry lic acid into lard. This enzyme was further studied for the effect of enzyme load, substrate ratib, reaction time, reaction temperature and added water content on the incorporation of caprylic acid into lard. HPLC analyzed the products from the acidolysis reaction. The highest incorporation was attained at 20% enzyme load. Time course studied suggest that the incorporation of caprylic acid into lard was increased up to 38.77 mol% after 24h. Desirable mole ratio of substrates was 1:2 (lard: caprylic acid), caprylic acid incorporation up to 30.95 mol%. In the range of 45 - 60 degrees C , temperature had no significant effect on enzyme activity and caprylic acid incorporation changed little. When temperature was above 60 degrees C, incorporation of caprylic acid into lard was decreased. The highest incorporation of caprylic acid into lard 35.76 mol% was attained when added water content was 2.5%.

[Isolation and identification of a strain DN2 degrading nicotine].

A bacterial strain which was able to utilize nicotine as its sole carbon source was isolated from soil in which tobacco had grown at Sanming region in FUjian Province and named as DN2. Upon chemotaxonomic characterization and phylogenetic inference based 16S rDNA analysis, the strain DN2 was identified as a-proteobacteria, Ochrobactrum intermedium. For DN2 degrading nicotine, the optimal pH and temperature is 6.5, 30 degrees C respectively. It can tolerate high-concentration of nicotine up to 4000 mg/L in basal media. Using 500 mg/L nicotine as its sole carbon, the strain was able to degrade 15 mg/L of nicotine per liter per hour and reached its stationary phase in about 36 hours.

[Media optimization for exopolysaccharide by Pholiota squarrosa (Pers. ex Fr.) Quel. AS 5.245 on submerged fermentation].

Our previous work has indicated that mycelium growth and exopolysaccharide accumulation in submerged fermentation by Pholiota squarrosa (Pers. ex Fr.) Quel. AS 5.245 are strongly affected by many internal and external factors, including medium constituents and fermentation conditions. In this study, we use an effective two-phase statistical approach to enhance exopolysaccharide production. In the first phase, Plackett-Burman design was undertaken to evaluate the effects of the twenty factors, i.e., glucose, fructose, maltose, yeast extract, tryptone, K2HPO4, KH2PO4, (NH4)2SO4, NaNO3, FeSO4, MgSO4, MnCl2, ZnCl2, FeCl3, CuSO4.5H2O, vitamin B1, initial pH, the temperature, the medium volume and the duration, to the fermentation. By regression analysis, yeast extract, tryptone, fructose, MgSO4, MnCl2, initial pH and temperature were found to be important for exopolysaccharide production, while glucose, maltose, NaNO3, ZnCl2, vitamin B1, the duration and the volume are important to the mycelium biomass. In the second phase of the optimization process, a response surface methodology (RSM) was used to optimize the above critical internal factors, and to find out the optimal concentration levels and the relationships between these factors. Based on the results of the first phase, a five-level six-factor (yeast extract, fructose, MgSO4, maltose, ZnCl2 and initial pH) central composite rotatable design (CCRD) was employed. By solving the quadratic regression model equation using appropriate statistic methods, the optimal concentrations for obtaining 876.32 microg exopolysaccharide per milliliter of fermentation liquor were calculated as: 6.0g/L yeast extract, 11.5g/L fructose, 0.5g/L MgSO4, 9.6g/L maltose, 38.6mg/L ZnCl2 and with the initial pH 5.3. The experimental data under various conditions have validated the theoretical values.