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Antibacterial Capacity (antibacterial + capacity)
Selected AbstractsPROTECTIVE CULTURES USED FOR THE BIOPRESERVATION OF HORSE MEAT FERMENTED SAUSAGE: MICROBIAL AND PHYSICOCHEMICAL CHARACTERIZATIONJOURNAL OF FOOD SAFETY, Issue 3 2008JAZILA EL MALTI ABSTRACT In this paper, 150 isolates, originating from horse meat, were subjected to step-by-step screening and characterization to search for potential protective cultures to be used in the meat industry. Isolates were first tested on their homofermentative and salt tolerance. Second, the antibacterial capacities toward Listeria monocytogenes were determined in an agar spot test. In total, 50% of the tested isolates were inhibitory toward Listeria monocytogenes. However, only 12 isolates produced a bacteriocin. Finally, three isolates with the strong bacteriocin activity were evaluated on their competitive nature by comparing their growth rate, acidifying character and lactic acid production at 15C under anaerobic conditions in a liquid broth. All three isolates combined a fast growth rate with a deep and rapid acidification caused by the production of high levels of lactic acid. Lactobacillus sakei was used as starter culture for producing sausage horse meat. In this study, fermentations were followed analyzing the microbiological and physicochemical aspects of this product. The sausages were characterized by an important microbial activity of lactic acid bacteria that resulted in a product with a final pH of about 4.56. No Listeria monocytogenes, Salmonella spp. or sulfite reducing clostridia were ever isolated from the raw materials or the fermented sausages during the maturation, underlining the microbial safety of this product. The final water activity of the product was 0.85. Starter cultures showed that Lactobacillus sakei was really efficient in reducing the amine production since this strain caused a quick pH drop during sausage fermentation. PRACTICAL APPLICATIONS A starter culture can be defined as a microbial preparation of large numbers of cells of at least one microorganism to be added to a raw material to produce a fermented food by accelerating and steering its fermentation process. The group of lactic acid bacteria (LAB) occupies a central role in these processes, and has a long and safe history of application and consumption in the production of fermented foods and beverages. They cause rapid acidification of the raw material through the production of organic acids, mainly lactic acid. Also, their production of acetic acid, ethanol, aroma compounds, bacteriocins, exopolysaccharides and several enzymes is of importance. The main reason for suitability of LAB is their natural origin, and they can contribute to food safety and/or offer one or more organoleptic, technological, nutritional or health advantages. [source] Antibacterial activity of plant extracts from northwestern ArgentinaJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2007J.R. Soberón Abstract Aims:, To determine the antibacterial and cytotoxic activities of aqueous and ethanolic extracts of northwestern Argentinian plants used in folk medicine. To compare the mentioned activities with those of five commercial antibiotics. To identify the compounds responsible for the antibacterial activity. Methods and Results:, Plant extracts were prepared according to traditional uses in northwestern Argentina. Antibacterial activity was assayed by agar dilution in Petri dishes and broth dilution in 96-well plates. Lethal dose 50 (LD50) was determined by the Artemia salina assay. Phytochemical analysis was performed by sample adsorption on silica gel, thin-layer chromatography (TLC), bioautography and UV-visible spectra. The results showed that Tripodanthus acutifolius aqueous extracts have lower minimal inhibitory concentrations (MIC) (502 and 506 ,g of extracted material (EM) per ml for infusion and decoction, respectively) than cefotaxim MIC (640 ,g ml,1) against Acinetobacterfreundii (303). These data were lower than their LD50. Tripodanthus acutifolius tincture showed lower MIC (110 ,g of EM per ml) and minimal bactericidal concentration (MBC) (220 ,g of EM per ml) than cefotaxim (MIC and MBC of 320 ,g ml,1) for Pseudomonasaeruginosa. This extract also showed a MIC/MBC of 110/220 ,g of EM per ml, lower than oxacillin (MIC/MBC of 160/220 ,g ml,1) for Staphylococcus aureus (ATCC 25923). The cytotoxicity of all extracts were compared with that of commercial antibiotics. Rutin (3,3,,4,,5,7-pentahydroxyflavone 3- , -rhamnosilglucoside), iso -quercitrin (3,3,,4,,5,7-pentahydroxyflavone 3- , -glucoside) and a terpene would be partially responsible for the antibacterial activity of T. acutifolius infusion. Conclusions:,Tripodanthus acutifolius extracts had the ability to inhibit bacterial growth. The antibacterial activity differs with the applied extractive method, and it could be partially attributed to glycoflavonoids. This paper contributes to the knowledge of antibacterial capacity of plants from northwestern Argentina. Significance and Impact of the Study:, These antibacterial activities support further studies to discover new chemical structures that can contribute to alleviate or cure some illnesses. [source] Effect of triclosan on interferon-, production and major histocompatibility complex class II expression in human gingival fibroblastsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2000Manal Mustafa Abstract Background, aims: The effect of triclosan (2,4,4,-trichloro-2,-hydroxyl-diphenyl ether) on the production of interferon-, (IFN-,) and the expression of major histocompatibility complex (MHC) class II antigen was studied in human gingival fibroblasts isolated from 4 individuals. Methods/Results: AII cell lines demonstrated high IFN-, production in 24-h cultures of human gingival fibroblasts stimulated by phytohemagglutinin (PHA) (5 ,g/ml). Human gingival fibroblasts showed a high expression of MHC class II when stimulated with 500 and 1000 pg/ml rIFN-, in 7-day cultures. Treatment of the cells with triclosan (0.5 ,g/ml) reduced both IFN-, production and MHC class II expression in human gingival fibroblast cultures. Similar inhibitory effects on IFN-, production and MHC class II expression were observed when the anti-inflammatory agent dexamethazone (1 ,M) was used. Conclusion: The present study further supports the view that the agent has an anti-inflammatory effect in addition to its antibacterial capacity. [source] Action of a silk fabric treated with AEGISTM in children with atopic dermatitis: A 3-month trialPEDIATRIC ALLERGY AND IMMUNOLOGY, Issue 4 2007D. Y. Koller Irritation of the skin of patients with atopic dermatitis by contact with rough fibres of synthetic or woollen clothes is well known. Therefore, it has been recommended that patients should wear cotton clothes. However, cotton also consists of rough fibres able to irritate the skin, whereas silk is characterized by smooth fibres without irritating potential. The aim of our study was to evaluate the clinical effect of Dermasilk®, a special silk fabric (sericin-free silk treated with AEGIS AEM5772/5 which has antibacterial properties) , in children with atopic dermatitis. A total of 22 children with mild-to-moderate atopic dermatitis were recruited for a study period of 3 months. All of them received three different tube-fabrics , Dermasilk, sericin-free silk fabric without AEGIS AEM 5772/5 and cotton, covering the cubital region. Patients were advised to wear the Dermasilk fabric all day long during the whole study period on one arm, whereas the sericin-free AEGIS-free silk tube had to be used during the first 2 wk only on the other arm followed by the use of the cotton tube for the rest of the study period. Evaluation of the local SCORAD score was carried out at the beginning of the study, after 2, 4, 8 and 12 wk. A significant reduction of the local SCORAD index of the Dermasilk covered arm was observed after 4, 8 and 12 wk in comparison with the cotton-covered arm score [median (quartile 1,quartile 3)] 6.5 (5,8) vs. 8 (7,9), p < 0.002; 6 (5.25,7.75) vs. 8 (7,9), p < 0.0001; and 6 (5,6) vs. 8 (7.25,10), p < 0.0001. The use of Dermasilk has a significant beneficial effect in atopic dermatitis because of the non-irritating properties of silk as well as the antibacterial capacity of AEGIS AEM 5772/5. [source] Synthesis and antibacterial properties of peptidyl derivatives and cyclopeptides structurally based upon the inhibitory centre of human cystatin C: Dissociation of antiproteolytic and antibacterial effectsAPMIS, Issue 7-8 2000FRANCISZEK Kasprzykowski Cysteine protease-inhibiting proteins of the cystatin superfamily can inhibit the replication of certain viruses and bacteria. The inhibitory centre of human cystatin C, the most widely distributed human cystatin, comprises three peptide segments. The present work describes the synthesis and antibacterial activity of 27 new peptidyl derivatives or cyclopeptides based upon the aminoterminal segment Arg8 -Leu9 -Val10 -Gly11. Fourteen of the new compounds displayed antibacterial activity against from 1 up to 9 of 17 clinically important bacterial species tested. Antiproteolytic activity of a compound was usually not required for its antibacterial capacity. Peptidyl diazomethanes generally had a very narrow antibacterial spectrum, inhibiting only Streptococcus pyogenes, whereas cyclopeptides and peptidyl derivatives of the general structure X-Arg-Leu-NH-CH(iPr)-CH2 -NH-Y had a much wider spectrum. The most potent of these substances displayed approximately equal minimal inhibitory and bactericidal concentrations of about 20 ,g/ml for both Staphylococcus aureus and S. pyogenes and were devoid of antiproteolytic activity. Several of the new substances could protect mice against lethal intraperitoneal challenge with S. pyogenes. Though their target remains to be disclosed, the group of substances here reported might be promising for the development of antibacterial drugs and the discovery of novel principles of action. [source] | ||||||||||