Bacteriostatic Circle Research Articles

The Adhesion and Antimicrobial Properties of Nano Silver/Chitosan Composite Membrane in Orthogonal Research

Research the nanosilver and other composite materials with the chitosan in the best composition with orthogonal test method. According to the best use concentration of nanosilver and composite materials carry out the orthogonal experiment. By using the ultrasonic method test the adhesion strength between chitosan membrane and the breeding net through calculating the loss of the membrane. With bacteriostatic circle method to determine the bacteriostatic effect of membrane. The results show that the main factors influence the adhesion of membrane and the effectiveness of bacteriostatic is adhesives and nanosilver. The orthogonal experiment results show that the optimum conditions of film forming as follows: the adhesion agent A3% , adhesion reagent B3% ,nanosilver solution 2% nanoantibacterial powder 3% ,tea saponin solution 60 mg/L. Under these conditions, the loss of the membranewas14.6%, the inhibition zone was 2.35cm. Orthogonal test was applied to the ratio of composite materials can get the best composite columns. Creating a better performance of target product and has a promising prospect for practical application.

Research on the Preparation and Antibacterial Property of Nanometer-Magnesium Oxide Powder

With the H2C2O4·2H2O and Mg(NO3)2·6H2O as the raw materials, nanometer-MgO powder was synthesized at different temperature by the low temperature solid phase method. After the characterization of the structure and property of this kind of nanometer-MgO powder with TG, XRD, SEM and FT-IR, etc, the antibacterial property of nanometer-MgO powder toEscherichia ColiandStaphylococcus Aureuswas examined through the bacteriostatic circle method. The results indicated that the powder was single crystal, complete crystallization and uniform distribution with the 10 nm of particle size. It had better resistance and capacity of killing bacteria and the diameter of the bacteriostatic circle was greater than 19 mm.

Synthesis, characteristics, and antibacterial activity of a rare-earth samarium/silver/titanium dioxide inorganic nanomaterials

An inorganic nanomaterials combination of Sm, Ag, and TiO2 was synthesized using supercritical fluid drying (SCFD) combined with sol-gel techniques. The structure, photocatalysis and bacteriostatic activity of the materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XRPS), photocatalytic performance, and antibacterial activity experiments. The XRD results showed that the average particle diameter of Sm/Ag/TiO2 was 14.62 nm and Ag and Sm ions were dispersed on the surface of TiO2 in a highly dispersed, amorphous form. The TEM image showed that the size of the particle was 12 nm using the scherer formula. The XPS result showed that the element Sm was doped and Ag was loaded inorganic nanomaterials successfully. Sm/Ag/TiO2 exhibited optimal photocatalytic properties at 600 °C, the photocatalytic optimal proportion of Sm/Ag/TiO2 was 2:2:100. When the molar ratio was 2:2:100, the bacteriostatic circle diameter was 16 mm for Staphylococcus aureus, the minimum bacteriostatic concentration was 200 μg/mL for white beads coccus, and the minimum bactericidal concentration was 2×104 μg/mL for white beads coccus. The SEM results showed that the antibacterial material attached to the candida albicans cell surface, cells appeared fold deformation. Therefore the inorganic nanomaterials Sm/Ag/TiO2 had high temperature resistance, good photocatalytic and antibacterial characteristics in visible light.

Research on Properties of Antibacterial Paper Sprayed by Nano-Chitosan

Antibacterial paper for packaging was sprayed by nanochitosan as antibacterial ingredients. The bacteriostatic circle method was adopted to evaluate its antibacterial effect on E.coli and Staphylococcus aureus. We investigated the effects of different concentrations of nanochitosan on antibacterial paper thickness, tensile strength, bursting strength, folding strength and antibacterial properties.The results showed that: tensile strength, bursting strength and folding strength of the antibacterial paper is better than the control paper and the thickness has no obvious change. The antibacterial paper enhanced the antibacterial effect following the increasing concentration of nanochitosan. The same concentration of nanochitosan antibacterial paper, its inhibitory effect on E.coli was greater than that of Staphylococcus aureus.

Studies on Antimicrobial Activity of Aqueous Extract of Maize Silk

Objective: To study antimicrobial activity of aqueous extract of maize silk. Methods: Choose Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, Bacillus coli and Candida albicans as detected germs. Using methods of agar plated diffusions and tube continuous dilution to detect antimicrobial activity and minimum inhibitory concentration of aqueous extract of maize silk. Results:(1) Aqueous extract of maize silk has antimicrobial activity against bacteria such as Staphylococcus aureus and Bacillus subtilis, and the diameter of bacteriostatic circle is 17 and 28 millimeter; Candida albicans is also inhibited by aqueous extract and its diameter of bacteriostatic circle is 24 millimeter.(2)The antimicrobial activity against Staphylococcus aureus and Bacillus subtilis is 500mg/ml and 62.5mg/ml.The minimum inhibitory concentration to Candida albicans is 125mg/ml.(3) aqueous extract of maize silk has no antimicrobial activity on Pseudomonas aeruginosa and Bacillus coli. Conclusion: Staphylococcus aureus, Bacillus subtilis and Candida albicans can be inhibited by aqueous extract of maize silk.

Study on Antibacterial Efficacy and Catalytic Capability of Nanocrystalline Magnesia

Abstract: Objective: To study the antibacterial efficacy and the catalytic capability of nanocrystalline magnesia powder(nano-MgO). Methods: The antibacterial efficacy was evaluated in Bacteriostatic circle and the shake flask test and the catalytic capability was evaluated by paraoxon. Results: The nano-MgO had good antibacterial efficacy and highly catalytic capability. The catalytic capability was not influenced by light. When 50mL 20μg/L paraoxon solution was catalyzed by 0.5g nano-MgO for 5min, the disappearance of paraoxon was about 77.9%, and for 60min, the disappearances of them was 99.6％. Conclusion：The nano-MgO had good antibacterial efficacy and highly catalytic capability. Key words: nanocrystalline magnesia , antibacterial efficacy, paraoxon, catalytic degradation

10-Hydroxy-2-decenoic Acid as an Antimicrobial Agent in Draft Keg-Conditioned Wheat Beer

In nature, 10-hydroxy-2-decenoic acid (10-HDA), an important unsaturated fatty acid, is only available in royal jelly. Natural 10-HDA exhibits several biological activities, including anticancer activity, and provides protection against acute radiation injury. In this study, we identified a method for extraction of 10-HDA from royal jelly. The antimicrobial effect of 10-HDA on beer-spoilage bacteria and yeast was investigated by flow cytometry and bacteriostatic circle (paper assay) experiments. We also determined the minimum inhibitory concentration of 10-HDA using the double-dilution method. Our results showed that 10-HDA could significantly inhibit common microorganisms, such as Lactobacillus brevis and Pediococcus damnosus, found in beer but had no inhibitory effect on yeast. A novel approach for preparing draft keg-conditioned wheat beer was developed using top-fermenting yeast strain 303 and bottom-fermenting yeast strain 308. The beer was then kegged for secondary fermentation. Because living yeasts were still in the beer, pasteurization could not be used, and it was difficult to keep everything clean and sanitary during brewing and kegging processes. In this study, 10-HDA was added to the green beer during kegging. We confirmed that 10-HDA, acting as an antimicrobial agent, increased the sanitary aspects of the kegged beer and improved the microbiological stability and shelf life of the beer.

Preliminary Study on High-level Expression of Tandem-Arranged Tachyplesin-Encoding Gene in Bacillus subtilis Wb800 and its Antibacterial Activity

To produce tachyplesin, an antimicrobial peptide, by a stable and efficient gene engineering approach, cDNAs containing single tachyplesin gene sequence (tac)(1) and tandem repeat of tachyplesin gene sequence (tac2) were respectively developed by annealing two synthesized complementary single-stranded DNAs and constructed into pSBPTQ shuttle vector under the control of the SacB.p.s promoter. The vectors containing the target gene sequence were then transformed into Bacillus subtilis WB800, respectively. Both expression of tac and tac2 were induced by 2% sucrose. The fermentation supernatant was purified by regenerated cellulose membrane tubing (MWCO 2000) and the secreted TAC(2) and TAC2 were about 5 and 10 mg/l of supernatant, respectively. The antimicrobial activities of TAC and TAC2 were measured by the size of bacteriostatic circle of the fermentation supernatants against Escherichia coli K88. Ultrastructural alteration of E. coli K88 and Salmonella typhimurium was observed under scanning electron microscope and transmission electron microscopy. The results showed that in comparison with TAC, TAC2 was expressed at a higher level and also indicating strong antimicrobial activity both in vitro and in vivo.