Transition metals are known to be enriched in organic-coated marine aerosols, but the impact these cations have on their surface properties is not well understood. Here the effect of Zn2+ enrichment on the surface properties of a dipalmitoylphosphatidylcholine (DPPC) monolayer was investigated and compared to that of the alkaline earth metal Sr2+, an ion not enriched in aerosols. Phase behavior...

Under appropriate conditions, the interaction of the plant alkaloid ryanodine with a single cardiac sarcoplasmic reticulum Ca(2+)-release channel results in a profound modification of both channel gating and conduction. On modification, the channel undergoes a dramatic increase in open probability and a change in single-channel conductance. In this paper we aim to provide a mechanistic framewor...

The mechanism of the Ba2+-induced contraction was investigated using intact and saponin-treated skinned smooth muscle (skinned muscle) strips of the rabbit mesenteric artery. After depletion of Ca2+ stored in the caffeine-sensitive site, greater than 0.65 mM Ba2+ evoked contraction in muscle strips depolarized with 128 mM K+ in Ca2+-free solution in a dose-dependent fashion, and the ED50 values...

The calcium/proton antiporter of Escherichia coli was characterized by measurement of the effect of divalent cations on the respiration-coupled quenching of the fluorescence of quinacrine or 9-aminoacridine in everted membrane vesicles. Energy-linked quenching of the fluorescence of aminoacridines is dependent on proton uptake into everted vesicles and provides an indirect assay for measurement...

Ca2+ -dependent inactivation (CDI) has recently been shown in heterologously expressed N-type calcium channels (CaV2.2), but CDI has been inconsistently observed in native N-current. We examined the effect of Ca2+ on N-channel inactivation in rat sympathetic neurons to determine the role of CDI on mammalian N-channels. N-current inactivated with fast (tau approximately 150 ms) and slow (tau app...

We report solid-state 17O NMR determination of the 17O NMR tensors for the keto carbonyl oxygen (O6) of guanine in two 17O-enriched guanosine derivatives: [6-17O]guanosine (G1) and 2',3',5'-O-triacetyl-[6-17O]guanosine (G2). In G1.2H2O, guanosine molecules form hydrogen-bonded G-ribbons where the guanine bases are linked by O6...H-N2 and N7...H-N7 hydrogen bonds in a zigzag fashion. In addition...

The complexation reactions between Mg2+, Ca2+, Sr2+ and Ba2+ metal cations with 15-crown-5 (15C5) were studied in acetonitrile (AN)-methanol (MeOH) binary mixtures at different temperatures using conductometric method. 15C54 forms 1:1 complexes with Mg2+, Ca2+ and Sr2+ cations in solutions. The Ma2+ cati...

Histamine secretion was induced by substance P, in a dose-dependent manner, from rat peritoneal mast cells, both in the presence and absence of Ca2+ in the medium, and disodium cromoglycate (DSCG) produced a dose-dependent inhibition of the histamine secretion in Ca2+-containing medium. However, in the absence of Ca2+, DSCG was ineffective or had a far weaker activity. Mg2+, Sr2+ and Ba2+ were ...

We assessed the spatial distribution of 35 elements in aquifer sediments and groundwater a crude-oil-contaminated show evidence dissolution barium (Ba), strontium (Sr), cobalt (Co), nickel (Ni) during hydrocarbon oxidation coupled to historic microbial Fe(III)-reduction near oil. Trace element plumes occur aquifer, where 50% Co, 47% Ni, 24% Ba, 15% Sr have been mobilized from sediment oil into ...