Efectos fetales y posnatales del tabaquismo durante el embarazo / Fetal and postnatal effects of smoking during pregnancy

Resumen La exposición al tabaco en el útero se asocia con un menor crecimiento fetal, una disminución en el peso al nacer y un incremento significativo de nacimientos con bajo peso. Por otra parte, diversos estudios han indicado que el tabaquismo materno puede provocar sobrepeso u obesidad y un aumento rápido de peso en la infancia, lo puede aumentar el riesgo de enfermedades cardiovasculares y diabetes tipo 2 en la adultez temprana. Los niños expuestos a humo de tabaco en la vida intrauterina, tienen un sistema autónomo hiperreactivo durante las primeras semanas de vida, un crecimiento desproporcionado entre el parénquima pulmonar y las vías aéreas (crecimiento disináptico pulmonar), una disminución en la función pulmonar, un riesgo aumentado de asma, bronquitis y sibilancias en el producto. Existen asociaciones entre el tabaquismo materno y la reducción de las capacidades psicomotoras infantiles, así como los problemas de conducta incluido el trastorno por déficit de atención/hiperactividad en la niñez. Se ha observado un aumento en el riesgo de neoplasias benignas en la infancia (hemangioma y quiste tiroideo), pero no de neoplasias malignas.

Abstract Exposure to tobacco in the uterus is associated with lower fetal growth, a decrease in birth weight and a significant increase in low birth weight births. On the other hand, several studies have indicated that maternal smoking can cause overweight or obesity and a rapid increase in weight in childhood, which can increase the risk of cardiovascular disease and type 2 diabetes in early adulthood. Children exposed to tobacco smoke in intrauterine life, have a hyperreactive autonomic system during the first weeks of life, a disproportionate growth in lung parenchyma and airways (pulmonary dysynaptic growth), a reduction in lung function, an Increased risk in asthma, bronchitis and wheezing in the product. There are associations between maternal smoking and the reduction of infant psychomotor abilities, as well as behavioral problems that include children attention-deficit/hyperactivity disorder. There has been an increase in the risk of benign neoplasms in childhood (hemangioma and thyroid cyst), but not malignant neoplasms.

Production of phytohormones, siderophores and population fluctuation of two root-promoting rhizobacteria in Eucalyptus globulus cuttings.

Vegetative propagation by stem cuttings and mini-cuttings has been used worldwide for growing Eucalyptus plants. However, clones and hybrids of this plant present a great variability in their rooting capacity, apart from a gradual decrease in the rooting potential due to the ontogenetic age of the mother plant. Several studies have demonstrated that some bacteria promote plant growth and rooting through the action of direct and indirect mechanisms that are not still completely clear. Considering this, the objective of this study was to assess the production of auxins, abscisic acid and siderophores in Bacillus subtilis and Stenotrophomona maltophilia, which in previous studies increased rooting of E. globulus cuttings. Additionally, the population of these bacteria in the rhizosphere, superficial tissues of the stem-base and callus of the mini-cuttings was identified, and quantified by real-time PCR. Only S. maltophilia produced IAA in the presence of tryptophan; none of the bacterial strains produced ABA, but both produced siderophores. A comparative analysis of the separation profiles showed that there is a diverse microbial community in the rhizosphere, and only S. maltophilia was capable of keeping its population at a density of 2.03 × 10(7) cells/mg in different tissues of the mini-cuttings. The results would indicate that the rooting stimulus in E. globulus could be related to the action of one or several mechanisms such as the production of auxins and siderophores, and it could also be associated with the ability of bacteria to stay in the rhizosphere or in plant callus tissues.

Thiosulphate oxidation by Thiobacillus thioparus and Halothiobacillus neapolitanus strains isolated from the petrochemical industry

Sulphur Oxidizing Bacteria (SOB) is a group of microorganisms widely used for the biofiltration of Total Reduced Sulphur compounds (TRS). TRS are bad smelling compounds with neurotoxic activity which are produced by different industries (cellulose, petrochemical). Thiobacillus thioparus has the capability to oxidize organic TRS, and strains of this bacterium are commonly used for TRS biofiltration technology. In this study, two thiosulphate oxidizing strains were isolated from a petrochemical plant (ENAP BioBio, Chile). They were subjected to molecular analysis by real time PCR using specific primers for T. thioparus. rDNA16S were sequenced using universal primers and their corresponding thiosulphate activities were compared with the reference strain T. thioparus ATCC 10801 in batch standard conditions. Real time PCR and 16S rDNA sequencing showed that one of the isolated strains belonged to the Thiobacillus branch. This strain degrades thiosulphate with a similar activity profile to that shown by the ATCC 10801 strain, but with less growth, making it useful in biofiltration.