RESUMO
The study of metabolism is undergoing a renaissance. Since the year 2002, over 50 genetically-encoded fluorescent indicators (GEFIs) have been introduced, capable of monitoring metabolites with high spatial/temporal resolution using fluorescence microscopy. Indicators are fusion proteins that change their fluorescence upon binding a specific metabolite. There are indicators for sugars, monocarboxylates, Krebs cycle intermediates, amino acids, cofactors, and energy nucleotides. They permit monitoring relative levels, concentrations, and fluxes in living systems. At a minimum they report relative levels and, in some cases, absolute concentrations may be obtained by performing ad hoc calibration protocols. Proper data collection, processing, and interpretation are critical to take full advantage of these new tools. This review offers a survey of the metabolic indicators that have been validated in mammalian systems. Minimally invasive, these indicators have been instrumental for the purposes of confirmation, rebuttal and discovery. We envision that this powerful technology will foster metabolic physiology.
Assuntos
Técnicas Biossensoriais , Transferência Ressonante de Energia de Fluorescência , Aminoácidos , Animais , Técnicas Biossensoriais/métodos , Transferência Ressonante de Energia de Fluorescência/métodos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Mamíferos/metabolismo , Microscopia de Fluorescência/métodosRESUMO
Results of a questionnaire study of 91 Jamaican patients with homozygous sickle cell (SS) disease and 59 Jamaican control subjects of similar socioeconomic status indicated a mean delay of 2.3 years in age at menarche and of 3.9 years in age at first pregnancy in SS disease. The mean interval between first sexual exposure and pregnancy was similar in the two groups. The delay in age at first pregnancy in SS disease resulted partly from the delay in puberty, but it also resulted from a further delay in first sexual exposure, with a mean interval between menarche and first sexual exposure of 2.6 and 4.4 years in control subjects and patients, respectively. Physical and social factors that related to this delay were reflected in the higher prevalence of casual unions in patients; this finding implied lesser sexual exposure. Although the similar interval between first sexual exposure and pregnancy did not suggest a lesser fertility in patients with SS disease, the number of infants born to patients with SS disease was less at all ages compared with Jamaican standards. This finding might reflect lesser fertility subsequent to the first pregnancy. (AU)