From Germacarbonyl Compounds’ Perspective: Glad to be Formed and Stable in the Real World

Germacarbonyl compounds are the germanium analogs of carbonyl compounds, and they require an inert atmosphere for stability. Making these compounds survive the ambient conditions was not feasible given the lability of the Ge=E bonds (E = O, S, Se, Te). However, the first examples of germacarbonyl compounds synthesized under ambient conditions by taking advantage of dipyrromethene ligand stabilization are detailed here; the isolated compounds are germanones 3-4, germacarboxylic acids 6-7, germaesters 9-10, and germaamides 12-13 with Ge=E bonds (E = S, Se). The germaamides 12-13 can react under atmospheric conditions with copper(I) halides offering air and water stable monomeric 14-15 and dimeric 16-19 copper(I) complexes (halide = Cl, Br, I). Apart from just binding, selectivity was also observed; thiogermaamide 12 and selenogermaamide 13 bind CuCl and CuBr, respectively, when treated with a mixture of copper(I) halides.

Dimercaptosuccinic Acid Functionalized Polystyrene Column for Trace Concentration Determination of Heavy Metal Ions: Experimental and Theoretical Calculation Studies

Metal ion studies in wastewater are required on a regular basis for environmental monitoring and assessment. Less metal ion concentrations and the interference from complex sample matrices remains challenging for instrumental quantification. Herein, we proposed a fix-bed solid phase extraction method, consisting of a newly prepared dimercaptosuccinic acid functionalized polystyrene beads. The ligand forms stable complex with Hg(II), Pb(II), and Cd(II), evident by experimental as well as density functional theory. The metal-ligand stabilization energy calculations, suggested the higher selectivity of polystyrene dimercaptosuccinic acid (PSDMSA) toward Pb(II) compared to Cd(II) and Hg(II). The prepared adsorbent was utilized to enrich Hg(II), Pb(II), and Cd(II) ions from environmental samples. Column parameters were studied in detail and optimized accordingly. The preconcentration factor for Hg(II), Pb(II), and Cd(II) were found to be 900, with the preconcentration limit of 0.74 µg L−1. The detection limit for Pb(II), Cd(II), and Hg(II) ions was found to be 1.3 ± 0.2, 1.5 ± 0.3, and 1.8 ± 0.3 ng L−1, respectively. The method accuracy was tested against systematic and continuous errors by standard addition method (<5% RSD). Real samples was successfully analyzed following the proposed method.

Wnt- and Glutamate-receptors orchestrate stem cell dynamics and asymmetric cell division

ABSTRACTWnt signalling regulates many aspects of cell biology. Wnt-pathway activation and its downstream effects have been extensively studied, but the dynamic analysis of Wnt-ligands on mammalian cellular membranes is obstructed by difficulties of visualization. We overcome this using microbead-tethered Wnts presented to single embryonic stem cells, which undergo Wnt-mediated asymmetric cell division (ACD). Through live imaging and genetic editing, we show that knockout of Wnt co-receptor Lrp5 promotes cytoneme formation and Wnt-recruitment, which requires Lrp6 and β-catenin. Lrp5 facilitates ligand-retention at the membrane, and alongside Lrp6 mediates Wnt-ligand stabilization and positioning. β-catenin or Wnt co-receptor knockout causes misorientation at mitosis, and all but Lrp5 are required for Wnt-orientated ACD. Surprisingly, ionotropic glutamate receptor (iGluR) activity enables initial Wnt-recruitment, positioning, and ultimately oriented ACD. Uniquely, we have scrutinized the early Wnt ligand-membrane interaction, linking roles of Wnt-pathway components and crosstalk with iGluRs in guiding cell fate determination by oriented ACD.