Association between Transcription Factor AP-2B genotype, obesity, insulin resistance and dietary intake in a longitudinal birth cohort study.

BACKGROUND: The development of obesity has a large genetic component, and the gene encoding the transcription factor 2 beta (TFAP2B) has been identified as one of the responsible factors. We investigated the effect of TFAP2B intron 2 variable number tandem repeat (VNTR) genotype on obesity, insulin resistance and dietary intake from 15 to 33 years of age. METHODS: The sample included both birth cohorts (originally n = 1176) of the longitudinal Estonian Children Personality Behaviour and Health Study. The association between TFAP2B genotype, and anthropometric measurements, glucose metabolism and dietary intake at ages 15, 18 and 25 years was assessed using the linear mixed-effects regression models. Differences in anthropometric measurements, biochemical measures, blood pressure and dietary intake between TFAP2B genotypes at different age, including data of the older cohort at age 33, were assessed by one-way ANOVA. RESULTS: Male homozygotes for the TFAP2B 5-repeat allele had significantly higher body weight, body mass index, sum of 5 skinfolds, proportion of body fat, waist circumference, hip circumference, waist-to-hip ratio, waist-to-height ratio, fasting insulin and HOMA index. In female subjects, homozygotes for the TFAP2B 5-repeat allele had significantly larger increase in the rate of change per year in body weight, body mass index and hip circumference between years 15 and 25. By age 33, the findings were similar. A decrease in daily energy intake from adolescence to young adulthood was observed. In males, heterozygotes had significantly smaller decrease in the rate of change per year in daily energy intake. CONCLUSIONS: The association of TFAP2B with the development of obesity and insulin resistance is present throughout adolescence to young adulthood in males. In females the effect of TFAP2B on obesity appears later, in young adulthood. The TFAP2B effect is rather related to differences in metabolism than energy intake.

Photocatalytic antibacterial activity of nano-TiO2 (anatase)-based thin films: effects on Escherichia coli cells and fatty acids.

Titanium dioxide is a photocatalyst with well-known ability to oxidise a wide range of organic contaminants as well as to destroy microbial cells. In the present work TiO2 nanoparticles with high specific surface area (150m(2)/g) were used to prepare nanostructured films. The TiO2 nanoparticle-based film in combination with UV-A illumination with intensity (22W/m(2)) comparable to that of the sunlight in the UV-A region was used to demonstrate light-induced antibacterial effects. Fast and effective inactivation of Escherichia coli cells on the prepared thin films was observed. Visualization of bacterial cells under scanning electron microscopy (SEM) showed enlargement of the cells, distortion of cellular membrane and possible leakage of cytoplasm after 10min of exposure to photoactivated TiO2. According to the plate counts there were no viable cells as early as after 20min of exposure to UV-A activated TiO2. In parallel to effects on bacterial cell viability and morphology, changes in saturated and unsaturated fatty acids - important components of bacterial cell membrane-were studied. Fast decomposition of saturated fatty acids and changes in chemical structure of unsaturated fatty acids were detected. Thus, we suggest that peroxidation and decomposition of membrane fatty acids could be one of the factors contributing to the morphological changes of bacteria observed under SEM, and ultimately, cell death.