Adhesión de streptococcus mutans sobre hidroxiapatita in vitro

En el presente trabajo se evalúa la adhesión de Streptococcus mutans a hidroxiapatitas de diferente naturaleza en una solución oral sintética. La adhesión microbiana fue determinada indirectamente por recuento de los microorganismos viables en suspensiones equilibradas con los sustratos. Los resultados obtenidos mostraron que, a baja concentración de inóculo, la adhesión de Streptococcus mutans puede ser descripta, razonablemente, mediante una única isoterma de Langmuir, introduciendo una pequeña corrección en cada muestra para dar cuenta de las diferencias en la macrorugosidad. La constante de afinidad resultó ser aproximadamente igual a 0,25´10- 8 (bacterias/mL)-1. La falta de influencia del sustrato se interpreta en términos del mecanismo de adsorción del S. mutans, y el gran tamaño de la bacteria, que disimula diferencias químicas y morfológicas de la superficie en la dimensión nanométrica. Estos resultados sugieren que la derivatización de la superficie con grandes polímeros puede ser una alternativa más útil para modificar la adhesión bacteriana. A altas concentraciones de inóculo, se dispara una adhesión multicapa, descrita por una ecuación modificada de Hill, con un coeficiente n = 3, que indica fuertes interacciones atractivas entre bacterias.Peer Reviewe

Anti-listeria Monocytogenes Activity Of Enterocins Microencapsulated By Ionic Gelation

The encapsulation of enterocins synthesized by . Enterococcus faecium CRL1385 through ionic gelation with calcium ions was analyzed. Different enterocins samples were lyophilised and encapsulated using low-methoxyl pectin as the coating material. Lipids present in milk butter were also added to control the release of antimicrobial peptides from the capsules. The morphology of fresh and freeze-dried capsules was examined using light microscopy and scanning electron microscopy, respectively. Antimicrobial activity of encapsulated bacteriocins was assessed against . Listeria monocytogenes 01/155 using the agar diffusion technique and direct contact in microplates. The capsules with higher lipid content showed a more spherical and uniform shape. Pathogen inhibition was observed for capsules prepared with different bacteriocin solutions both on solid (halo diameter = 8.5-13.5 mm) and in an aqueous medium (. ca. 2 log orders decline in . L. monocytogenes viability). The outcomes suggest that bacteriocin encapsulation through ionic gelation can be a potential alternative for the application of these antimicrobial peptides as biopreservatives in food. © 2012 Elsevier Ltd.2912126Anal, A.K., Singh, H., Recent advances in microencapsulation of probiotics for industrial applications and targeted delivery (2007) Trends in Food Science & Technology, 18, pp. 240-251(2002) Official methods of analysis of AOAC international, , AOAC, AOAC International, MarylandAudisio, M.C., Oliver, G., Apella, M.C., Effect of different complex carbon sources on the growth of Enterococcus faecium and on its bacteriocin synthesis (2001) International Journal of Food Microbiology, 63, pp. 235-241Audisio, M.C., Terzolo, H.R., Apella, M.C., Bacteriocin from honeybee beebread Enterococcus avium, active against Listeria monocytogenes (2005) Applied & Environmental Microbiology, 71, pp. 3373-3375Borgogna, M., Bellich, B., Zorzin, L., Lapasin, R., Cesàro, A., Food microencapsulation of bioactive compounds: rheological and thermal characterisation of non-conventional gelling system (2010) Food Chemistry, 122, pp. 416-423Bower, C.K., McGuire, J., Daeschel, M.A., Suppression of Listeria monocytogenes colonization following adsorption of nisin onto silica surfaces (1995) Applied & Environmental Microbiology, 61, pp. 992-997Champagne, C.P., Fustier, P., Microencapsulation for the improved delivery of bioactive compounds into foods (2007) Current Opinion in Biotechnology, 18, pp. 184-190Daba, H., Pandian, S., Gosselin, J.F., Simard, R.E., Huang, J., Lacroix, C., Detection and activity of a bacteriocin produced by Leuconostoc mesenteroides (1991) Applied & Environmental Microbiology, 57, pp. 3450-3455Gálvez, A., Abriouel, H., López, R.L., Omar, N.B., Bacteriocin-based strategies for food biopreservation (2007) International Journal of Food Microbiology, 120, pp. 51-70Gouin, S., Microencapsulation: industrial appraisal of existing technologies and trends (2004) Trends in Food Science & Technology, 15, pp. 330-347Hoffman, A.S., Hydrogels for biomedical applications (2002) Advance Drug Delivery Reviews, 43, pp. 3-12Ibarguren, C., Audisio, M.C., Farfán Torres, M.E., Apella, M.C., Silicates characterization as potential bacteriocin-carriers (2010) Innovative Food Science & Emerging Technologies, 11, pp. 197-202Ibarguren, C., Raya, R.R., Apella, M.C., Audisio, M.C., Enterococcus faecium isolated from honey synthesized bacteriocin-like substances active against different Listeria monocytogenes strains (2010) Journal of Microbiology, 48 (1), pp. 44-52Kopermsub, P., Varissaporn, M., Choochart, W., Potential use of niosomes for encapsulation of nisin and EDTA and their antibacterial activity enhancement (2011) Food Research International, 44, pp. 605-612Langdon, C.J., Levine, D.M., Jones, D.A., Microparticulate feeds for marine suspension-feeders (1985) Journal of Microencapsulation, 2 (1), pp. 1-11Mukai-Correa, R., Prata, A.S., Alvim, I.D., Grosso, C.R.F., Controlled release of protein from hydrocolloid gel microbeads before and after drying (2004) Current Drug Delivery, 1, pp. 265-273da Silva Malheiros, P., Daroit, D.J., Brandelli, A., Food applications of liposome-encapsulated antimicrobial peptides (2010) Trends in Food Science & Technology, 21 (6), pp. 284-292Siragusa, G.R., Dickson, J.S., Inhibition of Listeria monocytogenes on beef tissue by application of organic acids immobilized in a calcium alginate cell (1992) Journal of Food Science, 57, pp. 293-296Talukder, R., Fassihi, R., Gastroretentive delivery systems: hollow beads (2004) Drug Development and Industrial Pharmacy, 30 (4), pp. 405-412Teixeira, M.L., dos Santos, J., Silveira, N.P., Brandelli, A., Phospholipid nanovesicles containing a bacteriocin-like substance for control of Listeria monocytogenes (2008) Innovative Food Science & Emerging Technologies, 9, pp. 49-53Wan, J., Gordon, J., Hickey, M.W., Mawson, R.F., Coventry, M.J., Adsorption of bacteriocins by ingestible silica compounds (1996) Journal of Applied Microbiology, 81, pp. 167-173Willaert, R.G., Baron, G.V., Gel entrapment and micro-encapsulation: methods, applications and engineering principles (1996) Reviews in Chemical Engineering, 12, pp. 1-20

Adhesión de streptococcus mutans sobre hidroxiapatita in vitro

En el presente trabajo se evalúa la adhesión de Streptococcus mutans a hidroxiapatitas de diferente naturaleza en una solución oral sintética. La adhesión microbiana fue determinada indirectamente por recuento de los microorganismos viables en suspensiones equilibradas con los sustratos. Los resultados obtenidos mostraron que, a baja concentración de inóculo, la adhesión de Streptococcus mutans puede ser descripta, razonablemente, mediante una única isoterma de Langmuir, introduciendo una pequeña corrección en cada muestra para dar cuenta de las diferencias en la macrorugosidad. La constante de afinidad resultó ser aproximadamente igual a 0,25´10- 8 (bacterias/mL)-1. La falta de influencia del sustrato se interpreta en términos del mecanismo de adsorción del S. mutans, y el gran tamaño de la bacteria, que disimula diferencias químicas y morfológicas de la superficie en la dimensión nanométrica. Estos resultados sugieren que la derivatización de la superficie con grandes polímeros puede ser una alternativa más útil para modificar la adhesión bacteriana. A altas concentraciones de inóculo, se dispara una adhesión multicapa, descrita por una ecuación modificada de Hill, con un coeficiente n = 3, que indica fuertes interacciones atractivas entre bacterias.Peer Reviewe

Solar Energy Based Water Potabilization: Low-cost Technologies For Isolated Regions Of Latin America And The Caribbean

Low-cost technologies, based on the use of solar energy, are proposed in the framework of the OAS/AE/141/2001 project to provide safe drinking water in isolated rural populations of Latin America and the Caribbean, with scarce hydric and economical resources. The offered technologies are Solar Disinfection in Individual Units (SODIS-DSAUI), Arsenic Removal by Solar Oxidation (SORAS-RAOS) and Solar Heterogeneous Photocatalysis with Titanium Dioxide (HP). It was found that DSAUI can be applied in all cases for disinfection, although HP can treat simultaneously bacterial and chemical contamination. RAOS is efficient in synthetic samples but the applicability to real waters is very dependent on the water matrix. All results are described and discussed together with actions to impulse the application by disseminating the methods and educating the population.428742879Litter, M.I., Mansilla, H., (2001) Digital Grafic, , http://www.cnea.gov.ar/xxi/ambiental/aguapura/default.htm, Solar water disinfection in rural communities of Latin America, Project OEA/AE141. ISBN 987 43 6942 6, La PlataNavntoft, C., Dawidowski, L., Paladini, A., Blesa, M.A., Assessment of a simple UV radiation model for applications in photocatalytic systems in Argentina (2004) 12th SolarPACES Int. Symp., , Oaxaca, Mexico, OctoberWegelin, M., (2000) EAWAG News, 48. , 11-12, SeptemberWater & Sanitation in Developing Countries, , http:/www.sodis.ch, EAWAG-SANDECBlesa, M.A., Eliminación de contaminantes por fotocatálisis heterogénea (2001) CYTED VIII-G Network, , http://www.cnea.gov.ar/xxi/ambiental/CYTED/default.htm, Digital Grafic, La PlataHug, S., (2000) EAWAG News, 49. , 18-20, DecemberWegelin, M., Gechter, D., Hug, S., Mahmud, A., Motaleb, A., http://www.sandec.ch/WaterTreatment/Documents/SORAS.pdfLitter, M.I., (2002) Digital Grafic, , http://www.cnea.gov.ar/xxi/ambiental/aguapura/default.htm, Prospect of rural communities of Latin America for the application of low-cost technologies for water potabilization, Project OEA/AE141, La PlataIbáñez, J.A., Litter, M.I., Pizarro, R.A., (2003) J. Photochem. Photobiol. A: Chem., 157, p. 81Litter, M.I., Mansilla, H.D., (2003) Digital Grafic, , http://www.cnea.gov.ar/xxi/ambiental/aguapura/default.htm, Sunlight assisted arsenic removal in rural communities of Latin America, Project OEA/AE141, La PlataLitter, M.I., Jiménez González, A., (2004) Digital Grafic, , http://www.cnea.gov.ar/xxi/ambiental/agua-pura/default.htm, Advances in low-cost solar technologies for disinfection, decontamination and arsenic removal in waters of rural communities of Latin America (HP and RAOS methods), Project OEA/AE141, La PlataGarcía, M.G., D'hiriart, J., Giulitti, J., Lin, H., Custo, G., Del Hidalgo, M.V., Litter, M.I., Blesa, M.A., Solar light induced removal of arsenic from contaminated groundwater: The interplay of solar energy and chemical variables (2004) Solar Energy, 77, p. 60

Properties of the Bacillus Cereus strain used in probiotic CenBiot Propriedades da cepa de Bacillus cereus utilizada no probiótico CenBiot

Bacillus cereus CenBiot fulfilled the requirements to be used as probiotic. The spores showed D80 of 14 hs, inhibited Escherichia coli and Yersinia pseudotuberculosis after 24 hs in associative culture, were innocuous for suckling and adult mice and were not inhibited by antibiotics at low concentrations.<br>Bacillus cereus CenBiot possui as características necessárias para ser utilizada como probiótico. Os esporos apresentaram D80 de 14 hs, inibiram Escherichia coli e Yersinia pseudotuberculosis após cultivadas associativamente por 24 hs, foram inócuos para camundongos lactentes e adultos e não foram inibidos por antibióticos a baixas concentrações