Reactions of complexation of Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) ions with adenosine 5'-diphosphate
POLISH JOURNAL OF CHEMISTRY
Authors: Lomozik, L; Gasowska, A; Bregier-Jarzebowska, R
Abstract
The reaction of complexation has been studied in the systems of the ions: Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) with adenosine 5'-diphosphate. The composition and stability constants of the complexes formed have been determined by the potentiometric method. The presence of the species type: MHL, MLx, and MLOH has been confirmed and their mode of coordination has been identified on the basis of the spectral data. In the acidic solution, the coordination dichotomy N(1)/N(7) has been found in all systems studied. At pH above 7, the dichotomy does not occur in the systems with Cu(II), while in the systems with Hg(II) only phosphate groups are involved in metallation. In the synthesized solid complexes of Cd(II) with AMP or ADP, the metal ion is bound by the donor nitrogen atom N(I), and in the complexes with ATP by the nitrogen atom N(7) of the nucleotide. Moreover, in the species with adenosine di- and triphosphate, the oxygen atoms of the phosphate groups are engaged in the complexation, while in the species Cd(AMP), similarly as in the liquid phase, the phosphate group is not involved in metallation.
Transforming Growth Factor beta/Activin signaling in neurons increases susceptibility to starvation
PLOS ONE
Authors: Chng, Wen-bin Alfred; Koch, Rafael; Li, Xiaoxue; Kondo, Shu; Nagoshi, Emi; Lemaitre, Bruno
Abstract
Animals rely on complex signaling network to mobilize its energy stores during starvation. We have previously shown that the sugar-responsive TGF beta/Activin pathway, activated through the TGF beta ligand Dawdle, plays a central role in shaping the post-prandial digestive competence in the Drosophila midgut. Nevertheless, little is known about the TGF beta/Activin signaling in sugar metabolism beyond the midgut. Here, we address the importance of Dawdle (Daw) after carbohydrate ingestion. We found that Daw expression is coupled to dietary glucose through the evolutionarily conserved Mio-Mlx transcriptional complex. In addition, Daw activates the TGF beta/Activin signaling in neuronal populations to regulate triglyceride and glycogen catabolism and energy homeostasis. Loss of those neurons depleted metabolic reserves and rendered flies susceptible to starvation.