Quantitative thin-layer chromatographic determination of dihydroergot alkaloids

Direct, quantitative, thin-layer chromatographic methods for the determination of dihydroergot alkaloids are described, in particular the determination of dihydroergotamine with dihydroergokryptine as internal standard. The internal standard was added to plasma, which was extracted twice in dichloromethane; the organic phase was removed under nitrogen, the residue resolved in ethanol and applied on a silica gel G-60 plate. Dihydroergotamine and the internal standard can be measured directly by fluorescence, with excitation at 264 nm and with use of a Zeiss remission filter FL 39. The percentage recovery from this method is 49.17 ± 6.71% (plasma). These methods enable the determination of 10 pmol dihydroergotamine per ml of plasma (ca. 6.8 ng/ml) with a coefficient of variation of 10.3%. They have proved useful in biochemical and pharmaceutical applications.     

Intrinsically disordered Meningioma-1 stabilizes the BAF complex to cause AML

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Spectral and thermodynamic properties of Ag(I), Au(III), Cd(II), Co(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II), U(IV), and Zn(II) binding by methanobactin from Methylosinus trichosporium OB3b

Methanobactin (mb) is a novel chromopeptide that appears to function as the extracellular component of a copper acquisition system in methanotrophic bacteria. To examine this potential physiological role, and to distinguish it from iron binding siderophores, the spectral (UV–visible absorption, circular dichroism, fluorescence, and X-ray photoelectron) and thermodynamic properties of metal binding by mb were examined. In the absence of Cu(II) or Cu(I), mb will bind Ag(I), Au(III), Co(II), Cd(II), Fe(III), Hg(II), Mn(II), Ni(II), Pb(II), U(VI), or Zn(II), but not Ba(II), Ca(II), La(II), Mg(II), and Sr(II). The results suggest metals such as Ag(I), Au(III), Hg(II), Pb(II) and possibly U(VI) are bound by a mechanism similar to Cu, whereas the coordination of Co(II), Cd(II), Fe(III), Mn(II), Ni(II) and Zn(II) by mb differs from Cu(II). Consistent with its role as a copper-binding compound or chalkophore, the binding constants of all the metals examined were less than those observed with Cu(II) and copper displaced other metals except Ag(I) and Au(III) bound to mb. However, the binding of different metals by mb suggests that methanotrophic activity also may play a role in either the solubilization or immobilization of many metals in situ.     

In Sync with the Family: Children and Partners Influence the Sleep‐Wake Circadian Rhythm and Social Habits of Women

Different factors have been proposed to influence morningness‐eveningness, biological rhythms, and sleep‐wake cycles, but few studies focused on the influence of social habits. Here, we focus on the influence of children and partners on the social habits of women at different stages of their lives and on synchronization within the family. One hundred and seventy‐nine women participated in the study and were allocated into four groups: women without children, pregnant women without children, pregnant women with children, and non‐pregnant mothers. Morningness was predicted by the presence of children, and earlier chronotype was predicted by the presence of children, pregnancy, and age. Average sleep duration was longest in pregnant women. The presence of children was responsible for a difference in rise times of approximately 1.5 h on the weekend. Subjective sleep‐onset latencies were shortest in women with children. The synchrony between partners (husband/wife) was 0.46 in women without children, 0.79 in pregnant women, 0.40 in women with children, and 0.56 between mother and child. Partners’ chronotypes were highly correlated, as were those of mother and child. This study suggests children have a strong influence on their mother's lifestyle and sleep‐wake rhythm, far beyond the first months of life, and that children are a more important social factor than the male partner.