Las funciones metabólicas, endocrinas y reguladoras de la expresión genética del lactato / The metabolic, endocrine and regulatory functions of lactate gene expression

Resumen El lactato se considera un metabolito de desecho que se produce durante la fatiga muscular. En contraste con esta visión simplista, en este trabajo se proporcionan evidencias de las múltiples y complejas funciones de este metabolito. Se muestra que: 1) el lactato es el producto final de la glucólisis, independientemente de la concentración de oxígeno en el medio en el que se encuentren las células; 2) el lactato forma parte de 2 tipos de lanzadera, una que funciona en el espacio intermembranal de la mitocondria, y otra intercelular, que se encarga de alimentar con lactato a ciertos tipos celulares, como las neuronas o el músculo cardiaco; 3) en los espermatozoides, el lactato se transporta directamente a la matriz mitocondrial y allí se oxida para producir piruvato y NADH; 4) en el hígado, el lactato participa en la oxidación del etanol a través de la generación de peróxido de hidrógeno; 5) que dependiendo de la estirpe celular, el lactato puede funcionar como agente antiinflamatorio (endocrino) o regulador de la expresión génica.

Abstract Lactate is considered to be a waste metabolite produced during muscle fatigue. In contrast with this simplistic point of view, in this review we provide evidence of the multiple and complex functions of this metabolite. We show that: 1) lactate is the final product of the glycolysis regardless the oxygen concentration in the cell 2) lactate is part of two types of shuttle, one that functions in the intermembrane space of the mitochondrion, and another intercellular, which is responsible for feeding lactate to certain cell types, such as neurons or heart muscle, 3) in sperm, lactate is transported directly to the mitochondrial matrix and there it is oxidized to produce pyruvate and NADH, 4) in the liver, lactate participates in the oxidation of ethanol through the generation of hydrogen peroxide, 5) Depending on the cell line, lactate can function as anti-inflammatory agent (endocrine) and/or a regulator of gene expression.

Optimal Conditions for Production of Fermented Flour from Pumpkin (Cucurbita pepo L.) for Infant Foods

The aim of this study was to determine the optimal conditions for production of a fermented pumpkin flour by lactic fermentation using Lactobacillus plantarum and the effect of the fermentation on nutritional potential and functional properties of pumpkin. To achieve this, pumpkin fruit was collected in the Ngaoundere main market, peeled, sliced, and the flesh obtained was grated, pasteurized at 90ºC for 5 minutes and placed under lactic fermentation using L. plantarum (108 cfu/mL). The sample obtained was dried at 45ºC ± 2ºC for 24 hours and crushed to obtain a flour with particle size ≤ 500 µm. According to the Doehlert's plan used, time and temperature of fermentation varied from 24 to 96 hours and 30 to 50°C respectively. Responses sought were the optimal levels of total carotenoids and reducing sugars in the flours. Chemical composition of flour was determined to evaluate the effect of fermentation on food matrix used. Results indicate that to produce a pumpkin flour with highest content in both carotenoids and reducing sugars, optimal conditions of lactic fermentation with L. plantarum are 70h at 45°C. Under these conditions, there is a decrease of 72.1% of proteins and 67% of fibers, against an increase of 106% of reducing sugars. Total carotenoids content decreased by 4.6%, but the level is still higher than the threshold recommended for infant food formulation, while mineral content increases with fermentation. A reduction of anti-nutrients (phytates, tannins, phenolic compounds and oxalates) of more than 50% is also observed when fermenting pumpkin. The functional properties of fermented pulp show a decrease of water absorption capacity of 24% and an increase of 134.4% in bulk density. Fermented pumpkin flour could be used in infant food formulation, but need to be associated with other sources of proteins and minerals.

Antithrombotic Activity of Milk Protein Hydrolysates by Lactic Acid Bacteria Isolated from Commercial Fermented Milks

ABSTRACT In the last decade, thrombosis has been one of the pathologies with high incidence creating great concern in Health Institutes all around the world. Considering this, the aim of this research was to determine the antithrombotic activity of peptides released during lactic fermentation. Reconstituted skim milk powder was fermented by Lactobacillus casei Shirota and Lactobacillus johnsonii LA1 isolated from commercial fermented milks. The hydrolysis degree and proteolytic profile were analyzed by trinitrobenzenesulfonic acid spectrophotometry method and by peptide polyacrylamide electrophoresis gel separation. The milk fermented by Lactobacillus casei Shirota exhibited a higher concentration of free amino groups than that fermented by Lactobacillus johnsonii LA1. Additionally, in both fermentation systems peptides with molecular weights lower than 1.4 kDa were observed. The highest inhibition of thrombin (31.67±2.35%) was observed in milk fermented by Lactobacillus johnsonii LA1 at 10 hours of fermentation. Finally, no relationship was found between the antithrombotic capacity and the proteolytic profile.

Use of food wastes for the production of lactic silage

The goal of the present work was to produce lactic silage from food wastes. A factorial 2³ experimental design was applied using the following factors and levels: yogurt inoculum concentration (1 and 15%), sucrose (2 and 15%) and temperature (22 and 35 ºC) and as response variable, the soluble nitrogen content (SNC) at the end of the fermentation was considered. The best SNC output was for the treatment with 1 % of inoculum, 2 % of sucrose and temperature of 22ºC. The increase of SNC with regards to its initial content, from 0.17 % to 1.67 % for protein contents (PC) < 5 % corresponded to 882 % and from 0.65 % to 2.36 % for PC > 5 % represented 263 %. It was possible to produce a lactic silage and keep it stable for up to 30 days, which was enough storage time before being sent to a drying process for future use in animal feeding or compost.

Estabilidad de almacenamiento de ensilados biológicos a partir de residuos de pescado inoculados con bacterias ácido-lácticas / Storage stability of biological silage from fish remains added with lactic acid bacteria culture

Se elaboraron cuatro muestras por triplicado de ensilados biológicos para alimentación animal a partir de residuos de pescado, utilizando melaza como fuente de carbohidratos para el crecimiento de cuatro cepas de bacterias ácido-lácticas (BAL) aisladas de los mismos, sometidos a un tiempo de incubación de 72 horas y temperatura de 35 °C (±2 °C) para acidificar el producto como método de conservación. A continuación los ensilados se almacenaron durante 180 días a temperatura ambiente para evaluar la estabilidad en anaquel, por medio de análisis químicos, composición química proximal, aminograma, recuentos microbiológicos y algunos de tipo organoléptico del producto terminado. Las cepas fueron eficientes en el proceso de fermentación, causando inhibición del crecimiento de microorganismos indeseables y aportando características organolépticas agradables. El ensilado elaborado con la cepa C14 provocó el descenso del pH en menos de 72 horas de incubación. Ninguno de los productos sufrió deterioro evidente durante el almacenamiento; presentaron porcentajes aceptables de proteína, grasa, cenizas, carbohidratos y aminoácidos, que hacen del producto una fuente utilizable en formulaciones de alimentos para animales.

Four biological sil ages samples for animal feeding were made from fish remains in triplicate,using molasses like source of carbohydrate for the growth of four lactic acid bacteria(LAB) strains isolated from those remains and incubated during 72 hours and temperature of 35°C (±2°C) to acidify the product as preservation method. Then, the sil ages were storage for 180 days at room temperature to asses the shelf stability by conducting chemical, proximal chemical composition, amine assessment, microbiological counting and some sensory evaluation in final product. Bacteria cultures were efficient in fermentation process causing inhibition growth of undesirable bacteria and giving pleasant sensory characteristics. The silage inoculated with culture C14 made the pH decreased in less than 72 hours of incubation.Neither one of the products suffered clearly deterioration during storage and had acceptable percentages of protein, lipids, ashes, carbohydrates and amino acids; all these make this product as a feasible source to be use in feed animal recipes.