Production, characterization and kinetic model of biosurfactant produced by lactic acid bacteria

BACKGROUND Biosurfactants are surface active molecules produced by microorganisms which have the ability to disrupt the plasma membrane. Biosurfactant properties are important in the food, pharmaceu tical and oil industries. Lactic acid bacteria can produce cell-bound and excreted biosurfactants. RESULTS The biosurfactant-producing ability of three Lactobacillus strains was analyzed, and the effects of carbon and nitrogen sources and aeration conditions were studied. The three species of lactobacillus eval uated were able to produce biosurfactants in anaerobic conditions, which was measured as the capacity of one extract to reduce the surface tension compared to a control. The decreasing order of biosurfactant production was L. plantarum>Lactobacillus sp.>L. acidophilus. Lactose was a better carbon source than glu cose, achieving a 23.8% reduction in surface tension versus 12.9% for glucose. Two complex nitrogen sources are required for growth and biosurfactant production. The maximum production was reached at 48 h under stationary conditions. However, the highest level of production occurred in the exponential phase. Biosurfactant exhibits a critical micelle concentration of 0.359 ± 0.001 g/L and a low toxicity against E. coli. Fourier transform infrared spectroscopy indicated a glycoprotein structure. Additionally, the kinetics of fermentation were modeled using a logistic model for the biomass and the product, achieving a good fit (R2 > 0.9). CONCLUSIONS L. plantarum derived biosurfactant production was enhanced using adequate carbon and nitrogen sources, the biosurfactant is complex in structure and because of its low toxicity could be applied to enhance cell permeability in E. coli

Ideación suicida y factores asociados en internos de un establecimiento penitenciario de Antioquia (Colombia) / Suicidal ideation and associated factors in inmates of a prison of Antioquia, Colombia

Introducción: La conducta suicida muestra altas cifras en población carcelaria; por ello se realizó la presente investigación, que tiene por objetivo identificar los factores sociodemográficos, familiares, personales y de reclusión asociados a la ideación suicida en internos de un establecimiento penitenciario de Antioquia, Colombia. Material y métodos: Se realizó un estudio descriptivo transversal. Se aplicó el Inventario de Orientación Suicida ISO-30 y una encuesta para indagar aspectos sociodemográficos, familiares y de reclusión de un grupo de 154 reclusos. De la información recolectada, se realizó un análisis univariable y bivariable con ayuda de los programas Excel y OpenEpi. Resultados: El 14,9% presentó ideación suicida alta. Al analizar la distribución de la ideación suicida alta en las variables estudiadas, se encontró que los porcentajes más altos se presentaron en los que tenían intento previo (61,1%), quienes presentaban antecedentes de violencia intrafamiliar en el hogar (50,0%), quienes no tenían escolaridad (33,3%), los que tenían antecedentes familiares de suicidio (28,6%) y los que no tenían definida la condena (22,9%). Se halló asociación significativa entre ideación y haber hecho intentos previos de suicidio (p < 0,01; rp = 7,4); provenir de hogares con violencia intrafamiliar (p = 0,03; rp = 4,0); estar soltero (p = 0,04; rp = 2,2) y ser menor de 30 años (p = 0,04; rp = 2,2). Conclusiones: Los porcentajes de ideación suicida alta son muy superiores a lo encontrado en población general, por lo que se recomienda a los profesionales de la institución abordar los factores de riesgo aquí hallados, con el fin de realizar programas de prevención e intervención.

Introduction: Suicidal behavior shows high numbers in prison population; hence, the following research was developed, which aimed to identify the sociodemographic, family, personal and imprisonment factors that are associated with suicidal ideation in inmates of a prison of Antioquia, Colombia. Material and methods: A cross descriptive study was carried out. It was applied the Suicide Orientation Inventory Test ISO-30, as well as a survey, in order to investigate sociodemographic, family and imprisonment aspects of a group of 154 inmates. Univariate and bivariate analysis were applied to the collected data by using Excel and OpenEpi programs. Results: 14.9% had high suicidal ideation. By analyzing the distribution of high suicidal ideation in the variables studied, it was found that the highest rates occurred in those who had previous attempts, 61.1%; a history of domestic violence, 50.0%; no schooling, 33.3%; those with a family history of suicide, 28.6%; and those without a definite sentence 22.9%. A significant association was found between the ideation and having committed previous suicide attempts (P<.01; rp = 7.4), belonging to households with domestic violence (P=.03; rp = 4.0), being single (P=.04; rp = 2.2) and being under 30 years old (P=.04; rp = 2.1). Conclusions: The high suicidal rates are much greater than those found in the general population; it is therefore recommended to the professionals of the institution to address the risk factors found here, in order to develop prevention and intervention programs.

Nuevos estudios epidemiológicos de la leishmaniasis andina, con especial referencia a Huigra, Chimborazo, Ecuador

Los estudios sobre leishmaniasis andina ecuatoriana se han realizado en 3 importantes focos, Paute (2,300m-1,500m s.n.m), Alausí (2,300m-2,500m s.n.m) y Huigra (1,200m-1,500m). Las formas de la enfermedad en estos focos son similares entre si en los aspectos epidemiológico, clínico y parasitológico. Se ha sugerido, sin embargo, que en Huigra, las características ecológicas, incluyendo la biología del vector, eran diferentes a las de las otras áreas endémicas de leishmaniasis andina.