Antibiotics in the environment are a potential threat to environmental ecosystems as well as human health and safety. Antibiotics are designed to have a biological effect at low doses, and the low levels detected in the environment have turned focus on the need for more research on environmental occurrence and fate, to assess the risk and requirement for future regulation. This article describe...

Previous studies of Arnon, Whatley, and Allen (I), Krogmann, Jagendorf, and Arnon (Z), Good (3), and Stiller and Vennesland (4) have indicated that in noncyclic photophosphorylation only 1 adenosine triphosphate molecule is produced per pair of electrons. However, Winget, Isawa, and Good (5) have recently observed P/2eratios of 1.3 with the use of chloroplasts from various species incubated at ...

new macrocyclic polyether-diester ligands (3-5) containing the 4h-pyran-4-one subcyclic unit have been prepared by treating various glycols with dimethyl chelidonate (10). in the reaction of compound 10 with ethylene glycol and diethylene glycol, two noncyclic diester and tetraester (6-9) were produced in each case. the new marcocyclic ligand 4 formed stable complexes with benzylammonium perchl...

Nitrogen-containing pyridine and quinoline are outstanding platforms on which excellent ionophores and sensors for metal ions can be built. Steric and stereochemical effects can be used to modulate the affinity and selectivity of such ligands toward different metal ions on the coordination chemistry front. On the signal transduction front, such effects can also be used to modulate optical respo...

Ionomycin and A23187 are divalent cation ionophores with a marked preference for calcium. Studies using these ionophores have almost exclusively interpreted their results in the light of calcium elevation. It was the aim of this study to investigate the effects of ionomycin in osteoblatic MC3T3-E1 cells that are not attributable to its ionophoric properties. Thus, we have found that in contrast...