Screening Strains Produced Bacteriocins With Anti-Helicobacter Pylori And Studies On Its Antibacterial Mecbnism

Hp(Helicobacter pylori) is a kind of growth in gastric mucosal layers of gram-negative bacteria, is regarded as a major cause of chronic gastritis,peptic ulcer, also is the main trigger factor gastric cancer.The world health organization has been I class carcinogenic factor [1]. At present, the treating disease is still lacking effective drugs .Screening can inhibit helicobacter pylori candidate compounds is important to develop the drug treatment of gastritis gastrointestinal diseases.This study is based on finding strains produced bacteriocins that can inhibit Hp. Bacteriocins that fight against Hp were studied in oriented extraction, isolation, purification, structure identification, content determination,in vitro antagonist Hp active evaluation and antibacterial mechanism, as follows research findings:1. 5 of 45 strains showed antibacterial activity. Selecting PC-5 strains which showed the strong inhibit Hp activity as a test strain, and carry on the morphology observation and physiological and biochemical identification, as a result, it was identified as Bacillus subtilis.2. The optimal seed fermentation conditions produced by strains PC-5 is glucose: 5g/L, yeast anointed 10g/L, MgSO4 0.5 g/L, pH7.0 ,culture temperature 37℃, cultivate inoculation quantity 3% (V/V), with fluid volume 200ml /500ml bottle, cultivate24h, rotation speed 150r/min.and optimal fermentation conditions is glucose: 5g/L, yeast anointed 10g/L, MgSO4 0.5 g/L, pH7.0 ,culture temperature 35℃, cultivate inoculation quantity 4% (V/V), rotation speed 150r/min,tank pressure 0.06 MPa, minute respiratory volume 25L.3. One compound were obtained by combined use of macroporous adsorption resin, organic solvent extraction, silica gel column chromatography, They were identified as molecular weight of 309 lipid peptide bacteriocins ring(named A-Ⅲ), by spectroscopic data(ultraviolet spectrum,infrared spectrum, electrospray ionization- mass spectrometry) analysis.4. Established the reversed phase high performance liquid chromatography (HPLC) method to determine the content of A-Ⅲin fermenting.The condition is: chromatographic column: Hypersil C18 column; (150 mm x 4.6 mm, 5μm); detected wavelength: 203nm;Mobile phase: methanol-water (73:27); Velocity: 1mL ? min - 1; Column temperature: at room temperature. The results showed that a good linear relationship was established in the range 1.44μg～3.24μg for A-Ⅲwith the regression equation Y = 2×106X - 891076, (r = 0.9994). This method was simple, reliable, and suitable for fermenting A -Ⅲingredients in content determination and quality control.5. In vitro antagonist Hp results show that A-Ⅲcan be a very good inhibit Hp. A-Ⅲmain role in change Hp cell form, and made bacteria inactivation.