Novel Coumarin-Thiadiazole Hybrids and Their Cu(II) and Zn(II) Complexes as Potential Antimicrobial Agents and Acetylcholinesterase Inhibitors

A series of coumarin-thiadiazole hybrids and their corresponding Cu(II) and Zn(II) complexes were synthesized and characterized with the use of spectroscopic techniques. The results obtained indicate that all the coumarin-thiadiazole hybrids act as bidentate chelators of Cu(II) and Zn(II) ions. The complexes isolated differ in their ligand:metal ratio depending on the central metal. In most cases, the Zn(II) complexes are characteristic of a 1:1 ligand:metal ratio, while in the Cu(II) complexes the ligand:metal ratio is 2:1. All compounds were tested as potential antibacterial agents against Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacterial strains demonstrating activities notably lower than commercially available antibiotics. The more promising results were obtained from the assessment of antineurodegenerative potency as all compounds showed moderate acetylcholinesterase (AChE) inhibition activity

Synaptic Development of the Mouse Dorsal Lateral Geniculate Nucleus

The dorsal lateral geniculate nucleus (dLGN) of the mouse has emerged as a model system in the study of thalamic circuit development. However, there is still a lack of information regarding how and when various types of retinal and nonretinal synapses develop. We examined the synaptic organization of the developing mouse dLGN in the common pigmented C57/BL6 strain, by recording the synaptic responses evoked by electrical stimulation of optic tract axons, and by investigating the ultrastructure of identified synapses. At early postnatal ages (P14), when optic tract stimulation routinely evoked an excitatory postsynaptic potential/inhibitory postsynaptic potential (EPSP/IPSP) sequence, with the latter having both a GABA(A) and GABA(B) component. Electrophysiological and ultrastructural observations were consistent. At P7, many synapses were present, but synaptic profiles lacked the ultrastructural features characteristic of the adult dLGN, and little gamma-aminobutyric acid (GABA) could be detected by using immunocytochemical techniques. In contrast, by P14, GABA staining was robust, mature synaptic profiles of retinal and nonretinal origin were easily distinguished, and the size and proportion of synaptic contacts were similar to those of the adult. The emergence of nonretinal synapses coincides with pruning of retinogeniculate connections, and the transition of retinal activity from spontaneous to visually driven. These results indicate that the synaptic architecture of the mouse dLGN is similar to that of other higher mammals, and thus provides further support for its use as a model system for visual system development. J. Comp. Neurol. 518:622-635, 2010. (C) 2009 Wiley-Liss, In