Expression of GPD1 and SIP18 genes during rehydration in active dry industrial Saccharomyces cerevisiae cider-making yeast strains (ADY)

In this study we determined the influence of different sugar concentration in media, time of rehydration and type of strain on relative expression level of GPD1 and SIP18 genes of active dry cider-making yeast strains, followed by the assessment of the impact of rehydration on the fermentation process. High expression of SIP18 at the beginning of rehydration was shown to be due to high transcription of the gene during the drying process. High sugar concentrations of media initiated transcription of the GPD1 gene and triggered the cellular glycerol biosynthesis pathway in examined strains. Rehydration time and type of strain showed to have no statistically significant impact on the course of the fermentation; RT qPCR results depended mainly on the time of rehydration and sugar concentration of the medium. This is the first attempt to confront rehydration time and molecular mechanisms acting upon rehydration with the course of the fermentation process.

Rosiglitazone increases the expression of peroxisome proliferator-activated receptor-gamma target genes in adipose tissue, liver, and skeletal muscle in the sheep fetus in late gestation

Exposure to maternal overnutrition increases the expression of peroxisome proliferator-activated receptor-gamma (PPARgamma) in adipose tissue before birth, and it has been proposed that the precocial activation of PPARgamma target genes may lead to increased fat deposition in postnatal life. In this study, we determined the effect of intrafetal administration of a PPARgamma agonist, rosiglitazone, on PPARgamma target gene expression in fetal adipose tissue as well indirect actions of rosiglitazone on fetal liver and skeletal muscle. Osmotic pumps containing rosiglitazone (n = 7) or vehicle (15% ethanol, n = 7) were implanted into fetuses at 123-126 d gestation (term = 150 +/- 3 d gestation). At 137-141 d gestation, tissues were collected and mRNA expression of PPARgamma, lipoprotein lipase (LPL), adiponectin, and glycerol-3-phosphate dehydrogenase (G3PDH) in adipose tissue, PPARalpha and PPARgamma-coactivator 1alpha (PGC1alpha) in liver and muscle and phosphoenolpyruvate carboxykinase (PEPCK) in liver determined by quantitative real-time RT-PCR. Plasma insulin concentrations were lower in rosiglitazone-treated fetuses (P < 0.02). Rosiglitazone treatment resulted in increased expression of LPL and adiponectin mRNA (P < 0.01) in fetal adipose tissue. The expression of PPARalpha mRNA in liver (P < 0.05) and PGC1alpha mRNA (P < 0.02) in skeletal muscle were also increased by rosiglitazone treatment. Rosiglitazone treatment increased expression of PPARgamma target genes within fetal adipose tissue and also had direct or indirect actions on the fetal liver and muscle. The effects of activating PPARgamma in fetal adipose tissue mimic those induced by prenatal overnutrition, and it is therefore possible that activation of PPARgamma may be the initiating mechanism in the pathway from prenatal overnutrition to postnatal obesity.

GRB14, GPD1, and GDF8 as potential network collaborators in weight loss-induced improvements in insulin action in human skeletal muscle

Obesity is associated with insulin resistance in skeletal muscle; accordingly, weight loss dramatically improves insulin action. We sought to identify molecular remodeling of muscle commensurate with weight loss that could explain improvements in insulin action. Muscle from morbidly obese women was studied before and after gastric bypass surgery. Gastric bypass surgery significantly reduced body mass by approximately 45% and improved insulin action. We then assessed mRNA profiles using a stringent statistical analysis (statistical concordance with three probe set algorithms), with validation in a cross-sectional study of lean (n = 8) vs. morbidly obese (n = 8) muscle. Growth factor receptor-bound protein 14 (GRB14), glycerol-3-phosphate dehydrogenase 1 (GPD1), and growth differentiation factor 8 (GDF8; myostatin) significantly decreased approximately 2.4-, 2.2-, and 2.4-fold, respectively, after weight loss (gastric bypass). Increased expression of these transcripts was associated with increased obesity in the cross-sectional group (lean vs. morbidly obese muscle). Each transcript was validated by real-time quantitative RT-PCR assays in both study groups. Using Ingenuity Pathway Analysis, we show that all three transcripts are involved in the same regulatory network including AKT1, IGF1, TNF, PPARG, and INS. These results suggest that GRB14, GPD1, and GDF8 are weight loss-responsive genes in skeletal muscle and that the observed transcriptional modulation of these would be expected to improve insulin signaling, decrease triglyceride synthesis, and increase muscle mass, respectively, with weight loss. Thus our data provide a possible regulatory pathway involved in the development of insulin resistance in the morbidly obese state, and improvement of insulin resistance with weight loss.