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Although genistein, a soy isoflavone, has beneficial effects on various tissues, it is unclear whether it plays a role in physiological insulin secretion. Here, we present evidence that genistein increases rapid glucose-stimulated insulin secretion (GSIS) in both insulin-secreting cell lines (INS-1 and MIN6) and mouse pancreatic islets. Genistein elicited a significant effect at a concentration as low as 10 nmol/l with a maximal effect at 5 mol/l. The effect of genistein on GSIS was not dependent on estrogen receptor and also not related to an inhibition of protein tyrosine kinase (PTK). Consistent with its effect on GSIS, genistein increases intracellular cAMP and activates protein kinase A (PKA) in both cell lines and the islets by a mechanism that does not involve estrogen receptor or PTK. The induced cAMP by genistein, at physiological concentrations, may result primarily from enhanced adenylate cyclase activity. Pharmacological or molecular intervention of PKA activation indicated that the insulinotropic effect of genistein is primarily mediated through PKA. These findings demonstrated that genistein directly acts on pancreatic ␤-cells, leading to activation of the cAMP/PKA signaling cascade to exert an insulinotropic effect, thereby providing a novel role of soy isoflavones in the regulation of insulin secretion. Diabetes 55:1043-1050, 2006 S oy isoflavones have received widespread attention over the past few years because of their potential for preventing some highly prevalent chronic diseases. Genistein, the primary soy-derived isoflavone, has various biological actions, including a weak estrogenic effect by binding to estrogen receptors (1) and inhibiting protein tyrosine kinases (PTKs) (2). Studies on whether genistein has an effect on diabetes are very limited. Recent studies performed in animals and humans have shown that ingestion of soy protein associated with isoflavones moderates hyperglycemia (3,4), suggesting a beneficial role for soy in diabetes. However, it is not clear whether the beneficial effect of soy protein is due to genistein or other components. Data from recent animal studies suggest an antidiabetic effect of genistein presumably by a hypolipidemic effect (5). However, recent reports demonstrated that soy isoflavone administration lowered plasma glucose, whereas triglyceride levels were unaffected in obese and diabetic animals (6) and postmenopausal women (7). Therefore, although these data suggest that genistein may have a protective role in diabetes, the mechanism underlying these beneficial effects is still largely unknown.Few data exist on whether genistein has a direct effect on pancreatic ␤-cells. Several earlier studies demonstrated that genistein stimulates insulin secretion from a clonal pancreatic ␤-cell line (8) and cultured islets (9,10), whereas other studies have found an inhibitory effect on insulin secretion (11,12). These discrepant data may be the result of variations in the experimental conditions and model used. Nevertheless, the doses used in most of these studi...

The adrenal steroid dehydroepiandrosterone (DHEA) may improve vascular function, but the mechanism is unclear. In the present study, we show that DHEA significantly increased cell viability, reduced caspase-3 activity, and protected both bovine and human vascular endothelial cells against serum deprivation-induced apoptosis. This effect was dose dependent and maximal at physiological concentrations (0.1-10 nM). DHEA stimulation of bovine aortic endothelial cells resulted in rapid and dose-dependent phosphorylation of Akt, which was blocked by LY294002, a specific inhibitor of phosphatidylinositol 3-kinase (PI3K), the upstream kinase of Akt. Accordingly, inhibition of PI3K or transfection of the cells with dominant-negative Akt ablated the antiapoptotic effect of DHEA. The induced Akt phosphorylation and subsequent cytoprotective effect of DHEA were dependent on activation of Galphai proteins, but were estrogen receptor independent, because these effects were blocked by pertussis toxin but not by the estrogen receptor inhibitor ICI182,780 or the aromatase inhibitor aminoglutethimide. Finally, DHEA enhanced antiapoptotic Bcl-2 protein expression, its promoter activity, and gene transcription attributable to the activation of the PI3K/Akt pathway. Neutralization of Bcl-2 by antibody transfection significantly decreased the antiapoptotic effect of DHEA. These findings provide the first evidence that DHEA acts as a survival factor for endothelial cells by triggering the Galphai-PI3K/Akt-Bcl-2 pathway to protect cells against apoptosis. This may represent an important mechanism underlying the vascular protective effect of DHEA.

Using the iPro device for short-term (professional) blinded CGM in an office setting to improve hemoglobin A1c levels may not be a feasible goal for patients with type 1 and type 2 diabetes. The expectations of benefit, choice of patient, and choice of technology for short-term CGM are factors requiring careful consideration before testing takes place.

Overall, it appears that the AA/DHA-enriched formula modulated antigen-specific T cell responses in part through an interleukin 10-dependent mechanism.

Currently, in the United States, there are approximately 1 in 150 adults living with congenital heart disease (CHD) (). Infant and childhood mortality related to CHD decreased by 31% between 1987 and 2005 (). This survival trend is predicted to increase each year due to advancements in treatment and management of CHD. This significant shift in the epidemiology of CHD requires nurses to take action in preparing children with CHD and their families for their teenage years and young adulthood. The school-age child is the ideal age to begin teaching the child about their healthcare needs and how to care for themselves in preparation for the future. The school-age child with CHD has specific physical, intellectual, emotional, and developmental needs that must be considered and managed using a multidisciplinary approach. Pediatric nurses must be aware of these needs as they help the child and their family seamlessly and successfully transition into young adulthood as a happy and healthy CHD survivor.

Background The halophilic bacterium Chromohalobacter salexigens metabolizes glucose exclusively through the Entner–Doudoroff (ED) pathway, an adaptation which results in inefficient growth, with significant carbon overflow, especially at low salinity. Preliminary analysis of C. salexigens genome suggests that fructose metabolism could proceed through the Entner–Doudoroff and Embden–Meyerhof–Parnas (EMP) pathways. In order to thrive at high salinity, this bacterium relies on the biosynthesis and accumulation of ectoines as major compatible solutes. This metabolic pathway imposes a high metabolic burden due to the consumption of a relevant proportion of cellular resources, including both energy molecules (NADPH and ATP) and carbon building blocks. Therefore, the existence of more than one glycolytic pathway with different stoichiometries may be an advantage for C. salexigens. The aim of this work is to experimentally characterize the metabolism of fructose in C. salexigens . Results Fructose metabolism was analyzed using in silico genome analysis, RT-PCR, isotopic labeling, and genetic approaches. During growth on fructose as the sole carbon source, carbon overflow was not observed in a wide range of salt concentrations, and higher biomass yields were reached. We unveiled the initial steps of the two pathways for fructose incorporation and their links to central metabolism. While glucose is metabolized exclusively through the Entner–Doudoroff (ED) pathway, fructose is also partially metabolized by the Embden–Meyerhof–Parnas (EMP) route. Tracking isotopic label from [1- 13 C] fructose to ectoines revealed that 81% and 19% of the fructose were metabolized through ED and EMP-like routes, respectively. Activities of enzymes from both routes were demonstrated in vitro by 31 P-NMR. Genes encoding predicted fructokinase and 1-phosphofructokinase were cloned and the activities of their protein products were confirmed. Importantly, the protein encoded by csal1534 gene functions as fructose bisphosphatase, although it had been annotated previously as pyrophosphate-dependent phosphofructokinase. The gluconeogenic rather than glycolytic role of this enzyme in vivo is in agreement with the lack of 6-phosphofructokinase activity previously described. Conclusions Overall, this study shows that C. salexigens possesses a greater metabolic flexibility for fructose catabolism, the ED and EMP pathways contributing to a fine balancing of energy and biosynthetic demands and, subsequently, to a more efficient metabolism. Electronic supplementary material The online version of this article (10.1186/s12934-019-1178-x) contains supplementary material, which is available to authorized users.

The electron-transfer and proton-translocation activities of cytochrome c oxidase deficient in subunit III (Mr 29 884) prepared by native gel electrophoresis [Ludwig, B., Downer, N. W., & Capaldi, R. A. (1979) Biochemistry 18, 1401-1407] have been investigated. This preparation has been depleted of 82-87% of its subunit III content as quantitated by Coomassie Brilliant Blue staining intensity on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and [14C]dicyclohexylcarbodiimide labeling. The maximum rate of electron transfer of the subunit III deficient enzyme at pH 6.5 is 383 s-1, 78% of control enzyme. Neither the high-affinity site (Km = 10(-8) M) nor the low-affinity site (Km = 10(-6) M) of the cytochrome c kinetic interaction with cytochrome c oxidase is affected by the removal of subunit III. Subunit III deficient cytochrome c oxidase retains the ability to bind cytochrome c in both the high- and low-affinity sites as determined in direct thermodynamic binding experiments. Liposomes containing this preparation exhibit a respiratory control ratio [Hinkle, P. C., Kim, J. J., & Racker, E. (1972) J. Biol. Chem. 247, 1338-1341] of 3.9, while liposomes containing control enzyme exhibit a ratio of 4.3, suggesting that they have a similar proton permeability. Vectorial proton translocation initiated by the addition of ferrocytochrome c in liposomes containing subunit III deficient enzyme is decreased by 64% compared to those containing control enzyme. When the proton-translocated to electron-transferred ratio is measured in these phospholipid vesicles at constant enzyme turnover, removal of subunit III from the enzyme decreases the ratio from 0.52 to 0.21, a 60% decrease.(ABSTRACT TRUNCATED AT 250 WORDS)