Physicochemical composition and microbiological quality of goat milk produced in Santiago del Estero Province (Argentine)

The largest caprine milk shed of Argentina is located in Santiago del Estero province, but little information is available about the quality of the milk produced there. The present study consisted of two phases and had the objective of analyzing the physical-chemical composition and microbiological quality of the goat’s milk of this milk shed. In the first phase, milk from 30 small producer operations without defined animal breeds were analyzed with the following mean results: fat, 5.37%; protein, 3.39%; lactose, 4.32%; solids/not/fat (SNF), 8.30%; total solids (TS) 13.66%; acid degree value, 17.61ºD; pH, 6.76; density, 1.031 g/mL; total aerobic mesophiles, 4.96 log cfu/mL and proportion of samples positive for fecal coliforms, 72%. The second phase of the study involved three goat farms with different breeds and production levels exceeding the average of the zone. The milk from these farms did not differ much from the physical-chemical composition cited above, but two of them (T2 and T3) had outstanding contents of fat (5.59 and 5.52%) and TS (14.13 and 13.84%), resulting from their use of the Anglo Nubian breed and feeding based on grazing of natural pastures and supplementation with cereals. The farm T1, that employs the Saanen breed, had the highest mean milk production (1.44 kg/day) and the lowest acid degree value (16.49ºD), resulting from better management of the operation and more efficient cooling of the milk after milking. It is concluded that, eventhough better hygienic/sanitary management of the crude milk is needed, milk from this milk shed is well suited for cheese making

Effect of Daily Consumption of Lactobacillus reuteri CRL 1098 on Cholesterol Reduction in Hypercholesterolemic Subjects

The effect of daily consumption of a yogurt containing Lactobacillus reuteri CRL 1098 on the lipid profile of hypercholesterolemic subjects was evaluated by performing a prospective, randomized, double-blind, cross-over placebo controlled clinical study. Participants consumed daily a yogurt containing L. reuteri CRL 1098 or a placebo for four weeks, separated by a wash-out period. Total cholesterol, triacylglycerol, high-density (HDL) and low-density (LDL) lipoprotein levels were assessed at the beginning and at the end of each period. We found a statistically significant reduction of total (−7.86 g/dl) and LDL (−7.02 g/dl) cholesterol in absolute changes (before-after) as well as a decreasing trend in the group receiving the yogurt containing L. reuteri with respect to the placebo group, without detecting changes in HDL-cholesterol and triacylglycerol levels. Our results suggest that low amounts of yogurt (125 g/day) and low doses of the CRL 1098 strain (106 CFU) are sufficient to reduce total and LDL-cholesterol levels in hypercholesterolemic subjects.Facultad de Ciencias Médica

Lactobacillus acidophilus autolysins inhibit Helicobacter pylori in vitro

Antibacterial activity of 17 strains of lactobacilli was tested against 10 strains of H. pylori. The inhibition observed was related to the acid production and the low pH attained. No relationship between CagA phenotype of H, pylori strains and tolerance to lactic acid was observed. In mixed cultures, L. acidophilus CRL 639 showed an autolytic behavior after 24 h of culture. At this moment, H. py[ori CCUG17874 showed a decrease of 2 log-cycle, and no viable count was detected after 48 h, The bactericidal effect of L. acidophilus CRL 639 in mixed cultures is related to a proteinaceous compound released after cell lysis

Lactobacillus reuteri and their immunomodulatory compounds: Background for the developement of anti-inflammatory products

Las bacterias lácticas (BL) poseen numerosas propiedades benéficas para la salud del hospedador, entre las cuales se destaca su capacidad inmunomoduladora y anti-inflamatoria. Aunque la mayoría de los efectos benéficos de los probióticos requieren del contacto directo células-bacterias, algunos informes han demostrado que ciertos compuestos extracelulares secretados por BL, tales como proteínas/péptidos, son capaces de regular ciertas vías de señalización y respuestas celulares y promover así protección contra enfermedades inflamatorias. El objetivo de este trabajo de Tesis Doctoral fue profundizar en el estudio de los mecanismos celulares y moleculares a través de los cuales compuestos secretados por BL ejercen su actividad anti-inflamatoria mediante el empleo de modelos in vitro e in vivo y establecer las bases tecnológicas para el desarrollo de un producto anti-inflamatorio?.Ensayos in vitro empleando un modelo de células RAW 264.7 desafiadas con lipopolisacárido (LPS), permitió seleccionar a Lactobacillus reuteri CRL1098 por producir un compuesto de naturaleza peptídica en el sobrenadante de su cultivo (LrS 1098) capaz de estimular la producción de IL-10 y disminuir marcadores pro-inflamatorios como TNF-α, IL-6, COX-2, Hsp-70 y óxido nítrico (NO). También se demostró que LrS 1098 disminuye la apoptosis de células RAW 264.7 inducida por LPS.Para identificar los mecanismos moleculares por medio de los cuales LrS 1098 es capaz de modular la respuesta inflamatoria in vitro, se evaluó su acción sobre intermediarios claves de distintas vías de señalización intracelular. Se demostró que LrS 1098 induce la respuesta anti-inflamatoria mediante la activación de la vía ERK 1/2 y a través de la inhibición de la vía de PI3K/Akt y de la translocación de la subunidad p65 del factor NF-κB al núcleo.Para validar las propiedades anti-inflamatorias de LrS 1098, se ajustó un modelo in vivo de daño pulmonar agudo (DPA) inducido por LPS en ratones BALB/c. La administración intranasal de LrS 1098 redujo los parámetros evaluados de daño al tejido pulmonar, disminuyó el reclutamiento de células inmunes a las vías aéreas y la secreción de citoquinas pro-inflamatorias al pulmón. LrS 1098 demostró ejercer una actividad anti-inflamatoria más potente que la dexametasona empleada en el modelo in vivo.Por otra parte, se establecieron los aspectos tecnológicos para el desarrollo de un producto anti-inflamatorio. Se diseñó un medio de cultivo simplificado de bajo costo (medio PETG) para la producción de biomasa por L. reuteri CRL1098 empleando un diseño factorial fraccionario. Se evaluó la influencia de distintos nutrientes y diferentes parámetros (agitación, pH, fase de crecimiento) sobre el crecimiento de este microorganismo. Se formuló también un medio de producción de bajo costo (buffer citrato con el agregado de glucosa) en donde el microorganismo fue capaz de producir el compuesto anti-inflamatorio.Los resultados obtenidos en este trabajo de Tesis Doctoral representan un avance sobre el conocimiento de los mecanismos moleculares de acción de bacterias lácticas. Al mismo tiempo, valida in vivo la capacidad anti-inflamatoria de Lactobacillus reuteri CRL1098 y sienta las bases para el desarrollo de un producto para la prevención y tratamiento de desórdenes inflamatorios.Lactic acid bacteria (LAB) have several beneficial effects on the host health, which include their immunomodulatory and anti-inflammatory capability. Although most beneficial effects of probiotics require direct cell-bacteria interaction, some reports demonstrated that extracellular compounds secreted by LAB, such as proteins/peptides, are able to modulate signaling pathways and cellular responses; thereby, they promote protection against inflammatory diseases. The aim of this Thesis was to enlarge the knowledge of the cellular and molecular mechanisms involved in the anti-inflammatory activity of lactic acid bacteria secreted- compounds in in vitro and in vivo models. Besides, to determine the technological aspects for the development of an anti-inflammatory product. Using the in vitro model of RAW 264.7 cells stimulated with lipopolysaccharide (LPS), Lactobacillus reuteri CRL1098 strain was selected. The soluble factor (LrS 1098) secreted by L. reuteri was a peptide that stimulates IL-10 production and decreases pro- inflammatory mediators such as TNF-α, IL-6, COX-2, Hsp-70 and nitric oxide (NO). In addition, LrS 1098 reduces apoptosis of LPS-challenged RAW 264.7 cells. To gain insight into the molecular mechanisms involved in the immunoregulatory effect of LrS 1098, its influence on key intermediates of intracellular signaling pathways was evaluated in vitro. LrS 1098 induced an anti-inflammatory response by activating ERK 1/2 pathway, through reduction of PI3K/Akt pathway, and inhibition of p65-NF-κB subunit translocation into the nucleus. To evaluate in vivo LrS 1098 capacity to exert anti-inflammatory effect, a mice model of acute lung injury (ALI) induced by LPS was adjusted. The intranasal administration of LrS 1098 reduced inflammatory lung tissue damage, inflammatory cell recruitment to the airways and secretion of pro-inflammatory cytokines. LrS 1098 exerted a more potent anti-inflammatory activity than dexamethasone used in in vivo model. On the other hand, technological aspects for the development of an anti- inflammatory product were established. A simplified culture medium, named PETG, was designed for L. reuteri CRL1098 biomass production optimization using a fractional factorial model. The influence of several nutrients and different parameters such as agitation, pH and growth phase, on the growth of the microorganism, was evaluated. Finally, a low cost medium was formulated (citrate buffer with the addition of glucose) for the production of the anti-inflammatory compound. The results of this Thesis represent an advance on the knowledge of the molecular mechanisms of action of lactic acid bacteria. In addition, they validate the anti- inflammatory capability of Lactobacillus reuteri CRL1098 in vivo and provide a scientific base for the development of a product for the prevention or treatment of inflammatory diseases.Fil: Griet, Milagros. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Rodriguez, Ana Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Font de Valdez, Graciela. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin

Two-step production of anti-inflammatory soluble factor by Lactobacillus reuteri CRL 1098.

We have demonstrated previously that a soluble factor (LrS) produced by Lactobacillus (L.) reuteri CRL 1098 modulates the inflammatory response triggered by lipopolysaccharide. In this study, the production of LrS by L. reuteri CRL 1098 was realized through two steps: i) bacterial biomass production, ii) LrS production, where the bacterial biomass was able to live but did not proliferate. Therefore, the simultaneous evaluation of the effect of different factors on the growth and LrS production was performed. Biomass production was found to be dependent mainly on culture medium, while LrS production with anti-inflammatory activity depended on culture conditions of the biomass such as pH, agitation and growth phase. The L. reuteri CRL 1098 biomass and LrS production in the optimized culture media designed for this work reduced the complete process cost by approximately 95%, respectively to laboratory scale cost