Diagnóstico de la intolerancia a la lactosa / Diagnosis of lactose intolerance

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Interaction between lactic acid bacteria and yeasts in airag, an alcoholic fermented milk.

The interaction between nine lactic acid bacteria (LAB) and five yeast strains isolated from airag of Inner Mongolia Autonomic Region, China was investigated. Three representative LAB and two yeasts showed symbioses were selected and incubated in 10% (w/v) reconstituted skim milk as single and mixed cultures to measure viable count, titratable acidity, ethanol and sugar content every 24 h for 1 week. LAB and yeasts showed high viable counts in the mixed cultures compared to the single cultures. Titratable acidity of the mixed cultures was obviously enhanced compared with that of the single cultures, except for the combinations of Lactobacillus reuteri 940B3 with Saccharomyces cerevisiae 4C and Lactobacillus helveticus 130B4 with Candida kefyr 2Y305. C. kefyr 2Y305 produced large amounts of ethanol (maximum 1.35 g/L), whereas non-lactose-fermenting S. cerevisiae 4C produced large amounts of ethanol only in the mixed cultures. Total glucose and galactose content increased while lactose content decreased in the single cultures of Leuconostoc mesenteroides 6B2081 and Lb. helveticus 130B4. However, both glucose and galactose were completely consumed and lactose was markedly reduced in the mixed cultures with yeasts. The result suggests that yeasts utilize glucose and galactose produced by LAB lactase to promote cell growth.

Alberto Sols, teacher and mentor of spanish biochemists (1917-1989).

Biochemistry in Spain owes much to the figure of Alberto Sols. In words of Nobel Prize winner Severo Ochoa: "He has been the first scientist to establish successfully biochemistry in Spain." His intellectual rigour, care in experimental design, emphasis on quality, and attention to the presentation of results permeated far beyond his inner circle to the then fledging Spanish biochemical community. It would be difficult to find some Spanish biochemist of the generation that now starts to retire who has not been influenced in a way or another by the work of Sols. However, it is also likely that the new generations of biochemists and molecular biologists in the country ignore who was Sols and what their field owns to him. The following lines try to highlight some key points of his scientific biography, the circumstances in which they took place and the state of the corresponding research area at that moment.

[Nutrition and bone health. Lactose and bone].

Lactose, a disaccharide in milk or dairy products, is known to promote calcium absorption. The enzyme lactase is needed to digest lactose. Although lactase is secreted normally in childhood, the secretion is decreased with growth, and the activity becomes lower in adulthood. When the activity of lactase is low, lactose passes intact the small intestine and reaches the large intestine, could cause unpleasantness such as diarrhea and stomach ache. This is called lactose intolerance. In this paper, we discuss promotion of calcium absorption by lactose, lactose intolerance, and bone health.

The origins of lactase persistence in Europe.

Lactase persistence (LP) is common among people of European ancestry, but with the exception of some African, Middle Eastern and southern Asian groups, is rare or absent elsewhere in the world. Lactase gene haplotype conservation around a polymorphism strongly associated with LP in Europeans (-13,910 C/T) indicates that the derived allele is recent in origin and has been subject to strong positive selection. Furthermore, ancient DNA work has shown that the--13,910*T (derived) allele was very rare or absent in early Neolithic central Europeans. It is unlikely that LP would provide a selective advantage without a supply of fresh milk, and this has lead to a gene-culture coevolutionary model where lactase persistence is only favoured in cultures practicing dairying, and dairying is more favoured in lactase persistent populations. We have developed a flexible demic computer simulation model to explore the spread of lactase persistence, dairying, other subsistence practices and unlinked genetic markers in Europe and western Asia's geographic space. Using data on--13,910*T allele frequency and farming arrival dates across Europe, and approximate Bayesian computation to estimate parameters of interest, we infer that the--13,910*T allele first underwent selection among dairying farmers around 7,500 years ago in a region between the central Balkans and central Europe, possibly in association with the dissemination of the Neolithic Linearbandkeramik culture over Central Europe. Furthermore, our results suggest that natural selection favouring a lactase persistence allele was not higher in northern latitudes through an increased requirement for dietary vitamin D. Our results provide a coherent and spatially explicit picture of the coevolution of lactase persistence and dairying in Europe.

Revisión sistemática: tratamiento nutricional del cólico del lactante (y II) / Systematic review: dietary treatment of infant colic (and II)

Introducción: El cólico del lactante es un problema prevalente en el que se han ensayado a lo largo de la historia diversos tratamientos, ninguno de ellos definitivo. En los últimos años se han realizado nuevas propuestas terapéuticas, y han aparecido en el mercado las llamadas fórmulas anticólico (FAC), o confort. En el presente trabajo se realiza una revisión estructurada sobre el tratamiento nutricional del cólico del lactante, con el objetivo de integrar la información actual sobre este aspecto y establecer las pruebas existentes sobre la utilidad de distintas modalidades de tratamiento nutricional. Metodología: Se efectuó una revisión sistemática mediante búsqueda bibliográfica electrónica de los ensayos clínicos con diseño aleatorizado y controlado acerca del tratamiento nutricional del cólico del lactante. Se realizó un análisis de las modificaciones en la composición de las FAC en relación con la fórmula adaptada convencional, según los datos proporcionados por los fabricantes del producto. Resultados: Los 23 ensayos clínicos incluidos estudiaron seis modalidades de tratamiento nutricional: disminución de lactosa en la fórmula artificial, dieta hipoalergénica, adición de fibra, administración de soluciones azucaradas, probióticos y preparados fitoterápicos. Una proporción significativa de los trabajos analizados presenta problemas metodológicos, como un escaso número de pacientes, una alta tasa de pérdidas y sesgos de selección, que dificultan la extrapolación de sus resultados a la práctica clínica. De las distintas intervenciones nutricionales, la exclusión de proteínas de leche de vaca en lactantes con fórmula artificial, la administración de preparados fitoterápicos y la dieta hipoalergénica extensa en la madre del lactante han demostrado tener algún grado de eficacia. Se necesitan estudios adicionales para verificar la eficacia de otras modalidades de tratamiento nutricional (AU)

Introduction: Infant colic is a common problem for which there is still no definitive treatment, despite the many approaches that have been tested over the course of time. In recent years, a number of proposals have been made, and so-called anticolic or comfort milk formulas have appeared on the market. The aim of this report is to present a systematic review of the dietary treatment of infant colic in order to update the available information and to establish the utility of different forms of nutritional intervention. Methods: A systematic review of the electronic databases was conducted to search exclusively for studies classified as randomized, controlled clinical trials focusing on the dietary treatment of infant colic. The authors analyzed the modifications in the composition of the anticolic formulas, as compared to standard formula, according to the data provided by the manufacturers of the product. Results: Among the twenty-three clinical trials selected, six modalities of nutritional treatment were studied: reduction of lactose, low-allergen diet, fiber-enriched formula, sweetened solutions, probiotics and phytotherapeutic agents. Methodological problems, such as small sample size, high dropout rate and selection bias, were observed in a considerable number of the analyzed trials, making it difficult to extrapolate the results to clinical practice. Removing cow’s milk from the diet of bottle- fed infants and administration of phytotherapeutic agents and a low-allergen diet to the mothers of breast-fed infants have been found to have a certain degree of efficacy. Additional studies are needed to verify the utility of other modalities of dietary treatment (AU)

Covalent attachment of lactase to low-density polyethylene films.

Polymer films to which bioactive compounds such as enzymes are covalently attached offer potential for in-package processing of food. Beta-galactosidase (lactase) was covalently attached to surface-functionalized low-density polyethylene films. A two-step wet chemical functionalization introduced 15.7 nmol/cm2 primary amines to the film surface. Contact angle, dye assays, X-ray photoelectron spectroscopy, and appropriate protein assays were used to characterize changes in film surface chemistry after each step in the process of attachment. Glutaraldehyde was used to covalently attach lactase to the surface at a density of 6.0 microg protein per cm2 via reductive amination. The bond between the covalently attached lactase and the functionalized polyethylene withstood heat treatment in the presence of an ionic denaturant with 74% enzyme retention, suggesting that migration of the enzyme into the food product would be unlikely. The resulting polyethylene had an enzyme activity of 0.020 lactase units (LU)/cm2 (approximately 4500 LU/g). These data suggest that enzymes that may have applications in foods can be covalently attached to inert polymer surfaces, retain significant activity, and thus have potential as a nonmigratory active packaging materials.

The T/G 13915 variant upstream of the lactase gene (LCT) is the founder allele of lactase persistence in an urban Saudi population.

BACKGROUND: The prevalence of lactase persistence is high in Saudi Arabia. OBJECTIVE: To identify a DNA variant for the lactase persistence/non-persistence trait in adult Arabs in Saudi Arabia. METHODS: We sequenced DNA from 432 anonymous neonatal blood donors from five different regions of Saudi Arabia to cover the 400 bp region surrounding the previously identified lactase persistence/non-persistence variant C/T-13910 residing in intron 13 of the MCM6 gene. RESULTS: Two anonymous blood donors carried the C/T-13910 genotype. One variant, T/G -13915, residing 5 bp upstream of the C/T-13910 variant, was present in 332 of 432 (76.9%) of the neonatal samples, compatible with previous prevalence figures of lactase persistence in urban Saudi populations. Determination of disaccharidase activities in 25 intestinal biopsy samples showed a highly significant correlation between lactase activity and the T/G-13915 genotypes (p<0.001; Fisher exact test) as well as between the L:S ratio and the aforementioned genotypes (p<0.001; Fisher exact test). CONCLUSION: The T/G-13915 variant is the founder mutation of lactase persistence in an urban Saudi population. The results obtained here have implications for genetic testing of adult-type hypolactasia and to analysis of human evolution, the origin of cattle domestication and migrations of the populations in the Arabian peninsula.