Protective role of lactic acid bacteria and yeasts as dietary carcinogen-binding agents - a review.

The importance of food contaminants in the link between diet and cancer has been widely demonstrated. Therefore, different physical and chemical strategies for the control of human exposure to such dietary carcinogens has been explored; however, most of these strategies are complex, costly, and have low efficiency which limited their applications. Hence, microbiological methods have been receiving more attention. Recent in vitro and in vivo studies have indicated that lactic acid bacteria (LAB) and yeast may act as dietary carcinogen-binding agents. This review describes the promising protective role of strains belonging mainly to the Lactobacillus, Bifidobacterium and Saccharomyces genera by acting as dietary carcinogen-binding agents. This property suggests that these microorganisms may have a protective role by reducing the bioaccessibility of dietary carcinogens, thereby decreasing their toxic effects. The mechanisms by which the binding process takes place have not been completely elucidated; thus, the possible underlying mechanisms and factors influencing carcinogens-binding will be addressed.

In Silico Prediction and In Vitro Assessment of Multifunctional Properties of Postbiotics Obtained From Two Probiotic Bacteria.

In this study, a global metabolite profile using Raman spectroscopy analysis was obtained in order to predict, by an in silico prediction of activity spectra for substance approach, the bioactivities of the intracellular content (IC) and cell wall (CW) fractions obtained from Lactobacillus casei CRL 431 and Bacillus coagulans GBI-30 strains. Additionally, multifunctional in vitro bioactivity of IC and CW fractions was also assessed. The metabolite profile revealed a variety of compounds (fatty acids, amino acids, coenzyme, protein, amino sugars), with significant probable activities (Pa > 0.7) as immune-stimulant, anti-inflammatory, neuroprotective, antiproliferative, immunomodulator, and antineoplastic, among others. Moreover, in vitro assays exhibited that both IC and CW fractions presented angiotensin-converting enzyme-inhibitory (> 90%), chelating (> 79%), and antioxidant (ca. 22-57 cellular antioxidant activity units) activities. Our findings based on in silico and in vitro analyses suggest that L. casei CRL 431 and B. coagulans GBI-30 strains appear to be promising sources of postbiotics and may impart health benefits by their multifunctional properties.

Kinetic Energy of Emerging Neutrons Produced by Photodisintegration in a Medical Linear Accelerator / Energía cinética de neutrones emergentes producidos por fotodesintegración en un acelerador médico lineal

When a gamma photon interacts with a target nucleus a nuclear reaction can be generated, producing as a consequence the expulsion of particles from the atomic nucleus, this process is called photodisintegration. For this work, are of interest nuclear reactions of photodisintegration in which neutrons are ejected due to the interaction of photons with atomic nuclei of different materials in a linear accelerator for medical use. In this paper, the kinetic energy of photoneutrons produced by interactions with atomic nuclei of 184W, 63Cu, 27Al and 12C, which are some of the materials that constitute the head of a medical linear accelerator, is calculated. Also, the nuclei present in the construction materials of the room and the maze of the accelerator, such as, 23Na, 40Ca and 28Si, as also in the human body, ²H, 14N and 16O, are considered. It derives an exact theoretical expression, which has a linear dependence of the energy of the produced neutrons relative to the incident photon energy. It is found that, in the majority of cases, just photons with energies above 10 MV contribute to the production of neutrons. The values calculated from the expression obtained in this work are in good agreement with those reported in the literature, that are obtained by other approaches.

Cuando un fotón gamma interactúa con un núcleo blanco una reacción nuclear puede ser generada, produciendo como consecuencia la expulsión de partículas del núcleo atómico, este proceso se denomina fotodesintegración. Para este trabajo, son de interés las reacciones nucleares de fotodesintegración en las que los neutrones son expulsados debido a la interacción de los fotones con los núcleos atómicos de diferentes materiales en un acelerador lineal para uso médico. En este trabajo, la energía cinética de fotoneutrones producidos por la interacción con los núcleos atómicos de 184 W, 63 Cu, 27 Al y 12 C, que son algunos de los materiales que constituyen el cabezal de un acelerador lineal médico, es calculada. Además, los núcleos presentes en los materiales de construcción de la sala y el laberinto del acelerador, como por ejemplo, 23Na, 40Ca y 28Si, como también en el cuerpo humano, ²H, 14N y 16O, son considerados. Se obtiene una expresión exacta teórica, la cual tiene una dependencia lineal de la energía de los neutrones producidos en relación a la energía del fotón incidente. Se ha encontrado que, en la mayoría de los casos, sólo los fotones con energías por encima de 10 MV contribuyen a la producción de neutrones. Los valores calculados a partir de la expresión obtenida en este trabajo están en buen acuerdo con los reportados en la literatura, los cuales se obtienen mediante otros métodos.