Arabic gum, a new strategy for microbiological control in the dairy industry

The nutritional quality loss of food, usually is caused by microbial growth during different stages of production. Particularly in raw milk, the initial microbial content will affect the quality, shelf life and safety of processed milk and its derivatives. Traditionally, one of the strategies most used for reducing the risk of microbial contamination of raw milk, is storage under refrigeration immediately after to milking. However, this selectively favor the development of psychrotrophic microorganisms that can produce heat stable extracellular enzymes, causing alterations in the chemical composition and nutritional value of milk. In the last decade, the demand for minimally processed, easily prepared, and ready-to-eat fresh food products has grown globally, prompting the development of new methodologies as alternatives to thermal treatment. A growing trend is the addition of preservatives of natural sources, as a safe and healthy alternative to synthetics preservatives. The Arabic Gum (AG) is an edible biopolymer obtained as exudates of trees of Acacia, which is being widely used as a stabilizer, a thickener, and an emulsifier. However, to date, no antimicrobial activities studies have been conducted against psychrotrophics microorganisms. The aim of this work was to evaluate the effect of the addition of AG over the psychrotrophics bacterial growth, and viability. Several bacteria isolated from raw milk (Enterobacter spp.) were cultivated with different concentration of AG (0, 10, 20, 75, 100, 200, 400 M) during a period of 7 days at 4ºC and analyzed each 24 h. The bacterial growth in different conditions was evaluated by CFU counts, viability assays was performed using the LIVE/DEAD BacLight Bacterial Viability Kit (FACS), and metabolic activity was determined by colorimetric assay using tetrazolium salt (MTT). We observed that the addition of 200 and 400 M AG controlled proliferation of bacterial growth in more than a 50%, respect to the control condition and these effects were dose-dependent. In another hand, AG did not show significantly effect on the bacterial viability evaluated by the incorporation of propidium iodure. However using the tetrazolium salt as MTT we could determine that 75, 100, 200 and 400 M of AG were able to inhibit the metabolic activity of psychrotrophics bacterial growth significantly in all the assayed times. These data shown that AG had an important effect in the initial proliferation over psychrotrophic bacterial milk, which was maintained during analyzed times. Is important to hightlight that, for dairy factory the initial times are determinants to conserve the milk quality up to industrial processing, improving nutritional value in the final product. In base of these results, we can suggest that AG provides an additional beneficial effect to their usually technological use in food industry.Fil: Boiero, María Laura. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Gonzalez Estevez, Virginia. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Bachetti, R. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Morgante, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Porporatto, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Montenegto, Mariana. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Peer Reviewe

Evaluación comparativa por citometría de flujo y recuento en placa, de la actividad antimicrobiana de goma arábiga frente a microorganismos psicrótrofos

Una de las estrategias más aplicadas para la conservación de productos lácteos, es la refrigeración. Si bien el almacenamiento de leche a bajas temperaturas permite prolongar su vida útil, también favorece el desarrollo selectivo de microorganismos psicrótrofos (bacterias que crecen próximo a 0 °C) que producen enzimas hidrolíticas termorresistentes. Esto conduce a la pérdida de la calidad nutricional y organoléptica de la leche. La tendencia actual consiste en aplicar preservantes de origen natural, como una alternativa segura y saludable a los conservantes químicos. Goma arábiga (GA) es un biopolímero comestible obtenido del exudado de árboles Acacia Senegal y Seyal. Ésta se emplea comúnmente como agente espesante, estabilizante, emulsionante, en diversas industrias. Sin embargo, numerosos estudios indican que adicionalmente posee propiedades biológicas como antioxidante, contribución positiva sobre diferentes enfermedades, y actividad antimicrobiana. Es por ello que el objetivo del trabajo, fue evaluar la actividad antimicrobiana (AAM) de GA frente al desarrollo de microorganismos psicrótrofos aislados de leche cruda, almacenada a temperatura de refrigeración (4 °C), a través de la técnica de recuento en placa y comparar con la determinación de viabilidad por citometría de flujo (CMF). Los resultados obtenidos demostraron una relación entre los métodos de recuentos utilizados, indicando que GA, presenta AAM de sobre un microorganismo capaz de desarrollarse en leche, principalmente a altas concentraciones, aportando un efecto benéfico adicional a sus usos tecnológicos.Fil: Boiero, María Laura. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Gonzalez Estevez, Virginia. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Montenegro, Mariana. Universidad Tecnológica Nacional. Facultad Regional Villa María. Departamento de Ingeniería Química; Argentina.Fil: Breser, L. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Bachetti, R. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Morgante, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Fil: Porporatto, C. Universidad Nacional de Villa María. Centro de Investigaciones y Transferencia de Villa María; Argentina.Peer Reviewe

Regulatory T cells control strain specific resistance to Experimental Autoimmune Prostatitis

This deposit is composed by a publication in which the IGC' authors have had the role of collaboration (it's a collaboration publication). This type of deposit in ARCA is in restrictedAccess (it can't be in open access to the public), and could only be accessed by two ways: either by requesting a legal copy to the author (the email contact present in this deposit) or by visiting the following link: https://www.nature.com/articles/srep33097Susceptibility to autoimmune diseases results from the encounter of a complex and long evolved genetic context with a no less complex and changing environment. Major actors in maintaining health are regulatory T cells (Treg) that primarily dampen a large subset of autoreactive lymphocytes escaping thymic negative selection. Here, we directly asked whether Treg participate in defining susceptibility and resistance to Experimental Autoimmune Prostatitis (EAP). We analyzed three common laboratory strains of mice presenting with different susceptibility to autoimmune prostatitis upon immunization with prostate proteins. The NOD, the C57BL/6 and the BALB/c mice that can be classified along a disease score ranging from severe, mild and to undetectable, respectively. Upon mild and transient depletion of Treg at the induction phase of EAP, each model showed an increment along this score, most remarkably with the BALB/c mice switching from a resistant to a susceptible phenotype. We further show that disease associates with the upregulation of CXCR3 expression on effector T cells, a process requiring IFNγ. Together with recent advances on environmental factors affecting Treg, these findings provide a likely cellular and molecular explanation to the recent rise in autoimmune diseases incidence.Argentinean Agency for Promotion of Science and Technology; CONICET; National University of Córdoba grants; Cooperation Program in Science & Technology between Argentina and Portugal FCT–MINCYT

IL-10 Producing B Cells Dampen Protective T Cell Response and Allow Chlamydia muridarum Infection of the Male Genital Tract

A significant proportion of individuals develop chronic, persistent and recurrent genital tract infections with Chlamydia trachomatis, which has been attributed to the numerous strategies that the bacterium uses to subvert host immune responses. Animal chlamydia models have demonstrated that protective immune response is mediated by CD4+ Th1 cytokine responses. Herein, we demonstrate that early after infecting the male genital tract, C. muridarum triggers the production of IL-10 by splenic and lymph node cells. In addition, C. muridarum triggers IL-6 and TNFα secretion. Data obtained from in vitro and in vivo experiments revealed B cells as the major IL-10 contributors. Indeed, purified B cells produced high amounts of IL-10 and also exhibited enhanced expression of inhibitory molecules such as CD39, PD-L1 and PD1 after C. muridarum stimulation. In vitro experiments performed with sorted cell subsets revealed that Marginal Zone B cells were the main IL-10 producers. In vitro and in vivo studies using TLR-deficient mice indicated that TLR4 signaling pathway was essential for IL-10 production. In addition, in vivo treatments to neutralize IL-10 or deplete B cells indicated that IL-10 and B cells played a significant role in delaying bacterial clearance ability. Moreover, the latter was confirmed by adoptive cell transfer experiments in which the absence of IL-10-producing B cells conferred the host a greater capability to induce Th1 responses and clear the infection. Interestingly, NOD mice, which were the least efficient in clearing the infection, presented much more Marginal Zone B counts and also enhanced TLR4 expression on Marginal Zone B cells when compared to B6 and BALB/c mice. Besides, treatment with antibodies that selectively deplete Marginal Zone B cells rendered mice more capable of inducing enhanced IFNγ responses and clearing the infection. Our findings suggest that B cells play a detrimental role in C. muridarum infection and that activation by innate receptors like TLR4 and IL-10 production by these cells could be used by Chlamydia spp. as a strategy to modulate the immune response establishing chronic infections in susceptible hosts

Desarrollo de una estrategia terapéutica basada en combinaciones de sistemas poliméricos asociados a antibióticos para el tratamiento de infecciones intramamarias en bovinos

Fil: Breser, María L.. Universidad Nacional de Villa María; Argentina.Fil: Orellano, María Soledad. Universidad Nacional de Villa María; Argentina.Fil: Conesa, Agustín. Universidad Nacional de Villa María; Argentina.Fil: Saino, Verónica. Universidad Nacional de Villa María; Argentina.Fil: Falcón, Cristian R.. Universidad Nacional de Villa María; Argentina.Fil: Bianco, Ismael D.. Universidad Nacional de Villa María; Argentina

IL-10 Producing B Cells Dampen Protective T Cell Response and Allow Chlamydia muridarum Infection of the Male Genital Tract

A significant proportion of individuals develop chronic, persistent and recurrent genital tract infections with Chlamydia trachomatis, which has been attributed to the numerous strategies that the bacterium uses to subvert host immune responses. Animal chlamydia models have demonstrated that protective immune response is mediated by CD4+ Th1 cytokine responses. Herein, we demonstrate that early after infecting the male genital tract, C. muridarum triggers the production of IL-10 by splenic and lymph node cells. In addition, C. muridarum triggers IL-6 and TNFα secretion. Data obtained from in vitro and in vivo experiments revealed B cells as the major IL-10 contributors. Indeed, purified B cells produced high amounts of IL-10 and also exhibited enhanced expression of inhibitory molecules such as CD39, PD-L1 and PD1 after C. muridarum stimulation. In vitro experiments performed with sorted cell subsets revealed that Marginal Zone B cells were the main IL-10 producers. In vitro and in vivo studies using TLR-deficient mice indicated that TLR4 signaling pathway was essential for IL-10 production. In addition, in vivo treatments to neutralize IL-10 or deplete B cells indicated that IL-10 and B cells played a significant role in delaying bacterial clearance ability. Moreover, the latter was confirmed by adoptive cell transfer experiments in which the absence of IL-10-producing B cells conferred the host a greater capability to induce Th1 responses and clear the infection. Interestingly, NOD mice, which were the least efficient in clearing the infection, presented much more Marginal Zone B counts and also enhanced TLR4 expression on Marginal Zone B cells when compared to B6 and BALB/c mice. Besides, treatment with antibodies that selectively deplete Marginal Zone B cells rendered mice more capable of inducing enhanced IFNγ responses and clearing the infection. Our findings suggest that B cells play a detrimental role in C. muridarum infection and that activation by innate receptors like TLR4 and IL-10 production by these cells could be used by Chlamydia spp. as a strategy to modulate the immune response establishing chronic infections in susceptible hosts

Chitosan and cloxacillin combination improve antibiotic efficacy against different lifestyle of coagulase-negative Staphylococcus isolates from chronic bovine mastitis

Abstract Bovine mastitis affects the health of dairy cows and the profitability of herds worldwide. Coagulase-negative staphylococci (CNS) are the most frequently isolated pathogens in bovine intramammary infection. Based on the wide range of antimicrobial, mucoadhesive and immunostimulant properties demonstrated by chitosan, we have evaluated therapy efficiency of chitosan incorporation to cloxacillin antibiotic as well as its effect against different bacterial lifestyles of seven CNS isolates from chronic intramammary infections. The therapeutic effects of combinations were evaluated on planktonic cultures, bacterial biofilms and intracellular growth in mammary epithelial cells. We found that biofilms and intracellular growth forms offered a strong protection against antibiotic therapy. On the other hand, we found that chitosan addition to cloxacillin efficiently reduced the antibiotic concentration necessary for bacterial killing in different lifestyle. Remarkably, the combined treatment was not only able to inhibit bacterial biofilm establishment and increase preformed biofilm eradication, but it also reduced intracellular bacterial viability while it increased IL-6 secretion by infected epithelial cells. These findings provide a new approach to prophylactic drying therapy that could help to improve conventional antimicrobial treatment against different forms of bacterial growth in an efficient, safer and greener manner reducing multiresistant bacteria generation and spread