A novel hydrophilic analogue of parabens was synthetized and tested for its antimicrobial activity against selected microorganisms in model system. This study confirms antimicrobial potential of 1-O-(4-hydroxybenzoyl)-glycerol, which is comparable with other commercially used parabens. Unlike commercial parabens, it is possible to expect more significant antimicrobial activity of 1-O-(4-hydroxybenzoyl)-glycerol in real emulsion systems due to the increased solubility of this substance in water phase and also the lower skin irritation.

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Sedláčková P., Horáčková Š., Shi T., Kosová M., Plocková M. (2015): Two different methods for screening of bile salt hydrolase activity in Lactobacillus strains. Czech J. Food Sci., 33: 13-18.Bile salt hydrolase (BSH) activity of intestinal bacteria (including lactobacilli) is one of the indirect ways of decreasing a cholesterol level in human body. Tested Lactobacillus strains were isolated from various sources (faeces of fully breast-fed infants, cow's colostrum, cow's raw milk cheeses, and cow's raw milk) and identified by genotypic and phenotypic methods. All strains, including three commercial probiotic strains and six culture collection strains, were subsequently tested for their BSH activity via two methods -thin layer chromatography (TLC) and plate assay. Among all the 59 Lactobacillus strains, 15 strains were shown to be BSH positive by TLC method and only 8 of them by plate assay. Most of the BSH positive strains (9 strains) were isolated from faeces. Differences between BSH activities for sodium salts of cholyltaurine and cholylglycine were demonstrated. The TLC method was shown to be more sensitive compared to the plate assay for BSH activity determination.

Abstract:Složilová I., Purkrtová S., Kosová M., Mihulová M., Šviráková E., Demnerová K. (2014): Antilisterial activity of lactic acid bacteria against Listeria monocytogenes strains originating from different sources. Czech J. Food Sci., 32: 145-151.Eight individual bacteriocin-producing lactic acid bacteria (LAB) strains and three bacteriocin-non-producing cheese starter cultures were evaluated for their ability to inhibit the growth of six Listeria monocytogenes strains, originating from the guinea-pig lymph nodes, raw cow milk, and manufacturing dairy equipment. Results showed that either live cells or cell-free neutralised supernatant (CFNS) and/or heated CFNS of six individual LAB strains (Lcc. lactis subsp. lactis CCDM 416 and NIZO R5, Lbc. plantarum HV 11 and DC 1246, P. acidilactici HV 12, and Ent. mundtii CCM 1282) and one starter culture (DELVO-ADD ® 100-X DSF) were effective in the suppression of at least one listeria strain. Neither any individual LAB strain nor starter culture was antagonistic toward all studied L. monocytogenes strains, indicating diverse sensitivity/resistance among L. monocytogenes strains to antimicrobial compounds of LAB. The significant susceptibility of listerias isolated from raw milk and dairy equipment together with the strong antilisterial activity of DELVO-ADD ® 100-X DSF could be applied in dairy technology, where commonly used starter cultures could play both the biopreservative and fermentation role.

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The presented work was focused on the use of Ti6Al4V alloy with nanostructured surface and deposited silver nanoparticles as a material with antibacterial surface. Thanks to the electrochemically formed nanotubular oxide structure, a large area was available for silver deposition. Silver was photo-reduced from the silver nitrate solution. The ultrasonic treatment allowed the penetration of a silver source electrolyte into the whole depth of the tubes. Transmission electron microscopy images confirmed the presence of silver nanoparticles with size from units of nanometers up to 15 nm. Nanosilver was present throughout the length of the nanotubes. Samples with photoreduced silver will be able to provide antibacterial activity not only in critical hours after implantation but also in the longer term due to the subsequent release of silver from the volume of nanotubes. The prolonged antibacterial effect has been demonstrated against Staphylococcus aureus.

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