Intolerancia a la lactosa: mitos y verdades. Actualización / Lactose intolerance: myths and facts. An update

La lactosa es el principal carbohidrato de la leche materna. Es un disacárido conformado por glucosa y galactosa. Su producción en la glándula mamaria es independiente de la dieta materna. Además de proveer energía, es la única fuente de galactosa de la dieta, necesaria para la síntesis de macromoléculas como oligosacáridos, glicoproteínas y glicolípidos. Favorece la absorción y retención de calcio, magnesio y cinc. Su digestión por la enzima lactasa y posterior absorción tienen lugar en intestino delgado. El déficit de lactasa, que puede ser primario congénito (muy infrecuente), primario tardío o secundario por lesión intestinal, puede generar intolerancia con síntomas como dolor, distensión abdominal, flatulencia y diarrea. En el colon, bifidobacterias y lactobacilos pueden hidrolizarla. El manejo nutricional de la intolerancia deberá hacerse siempre preservando la lactancia materna. La reducción o suspensión de la lactosa deberá ser transitoria y se reemplazarán alimentos suspendidos por otros con adecuados aportes calóricos, proteicos y de minerales y vitaminas.

Lactose is the main carbohydrate present in humanmilk. It is a disaccharide made up of glucoseand galactose. It is produced in the mammaryglands, regardless of maternal diet. In addition toproviding energy, it is the only source of dietarygalactose, necessary for macromolecule synthesis,including oligosaccharides, glycoproteins, andglycolipids. It favors calcium, magnesium, andzinc absorption and retention. Its digestion bylactase and subsequent absorption occurs inthe small intestine. Lactase deficiency may beclassified into congenital primary (very rare),late-onset primary or secondary due to an injuryof the intestine; it may cause intolerance withpain, abdominal distension, abdominal gas, anddiarrhea. In the colon, it may be hydrolyzed bybifidobacteria and lactobacilli. The nutritionalmanagement of intolerance should alwayspreserve breastfeeding. Lactose reduction orelimination should be transient, and eliminatedfood should be replaced with other similar incalorie, protein, mineral, and vitamin content.

Structural-functional analyses of textile dye degrading azoreductase, laccase and peroxidase: a comparative in silico study

Background: Textile industry not only plays a vital role in our daily life but also a prominent factor in improving global economy. One of the environmental concern is it releases huge quantities of toxic dyes in the water leading to severe environmental pollution. Bacterial laccase and azoreductase successfully oxidize complex chemical structure of nitrogen group-containing azo dyes. Additionally, the presence of textile dye infuriates bacterial peroxidase to act as a dye degrading enzyme. Our present study deals with three textile dye degrading enzymes laccase, azoreductase, and peroxidase through analyzing their structural and functional properties using standard computational tools. Result: According to the comparative analysis of physicochemical characteristics, it was clear that laccase was mostly made up of basic amino acids whereas azoreductase and peroxidase both comprised of acidic amino acids. Higher aliphatic index ascertained the thermostability of all these three enzymes. Negative GRAVY value of the enzymes confirmed better water interaction of the enzymes. Instability index depicted that compared to laccase and preoxidase, azoreductase was more stable in nature. It was also observed that the three model proteins had more than 90% of total amino acids in the favored region of Ramachandran plot. Functional analysis revealed laccase as multicopper oxidase type enzyme and azoreductase as FMN dependent enzyme, while peroxidase consisted of α-ß barrel with additional haem group. Conclusion: Present study aims to provide knowledge on industrial dye degrading enzymes, choosing the suitable enzyme for industrial set up and to help in understanding the experimental laboratory requirements as well.

Intestinal enzymes during malnutrition & infection in rabbits.

BACKGROUND & OBJECTIVES: Malnutrition plays an important role in the intestinal absorption of nutrients. However, reports are not consistent whether intestinal enzymes are decreased in the presence of malnutrition. It is also not clear whether simultaneous presence of malnutrition and infection adds to the problem of malabsorption of nutrients. The aim of the present study was to determine intestinal functions in terms of concentrations of disaccharidase enzymes during diarrhoea and protein energy malnutrition. METHODS: Concentrations of three disaccharidase enzymes, namely maltase, sucrase and lactase were measured in nine energy-restricted and five control rabbits during diarrhoea induced by rabbit diarrhoeagenic Escherichia coli (RDEC-1). Malnutrition was achieved in the rabbit model by feeding the animals for 30 days with half the amount of food fed to well-nourished control rabbits. Both the energy-restricted and the control groups were challenged by RDEC-1. Diarrhoea occurred on day 1-7 after administration of the strain. After onset of diarrhoea, both groups of rabbits were sacrificed and their intestinal mucosa was examined to determine the concentration of lactase, maltase and sucrase. RESULTS: The energy-restricted animals and controls did not differ significantly for concentrations (units/mg proteins) of lactase (0.65 +/- 0.28 vs 0.56 +/- 0.17 ), maltase (6.20 +/- 2.70 vs 6.47 +/- 1.90) and sucrase (5.42 +/- 2.30 vs 5.13 +/- 1.40) measured during acute infectious diarrhoea. INTERPRETATION & CONCLUSION: The results suggested that the enzymatic functions of the intestinal brush border were not statistically different during diarrhoea among malnourished rabbits compared with their well-nourished counterparts.