Uptake of manganese by Brevibacterium ammoniagenes ATCC 6872 was energy dependent and obeyed saturation kinetics (Km = 0.65 microM; Vmax = 0.12 mumol/min per g [dry weight]). Uptake showed optima at 27 degrees C and pH 9.5. 54Mn2+ accumulated by the cells was released by treatment with toluene or by exchange for unlabeled manganese ions, via an energy-dependent process. Co2+, Fe2+, Cd2+, and Zn...

Cyclooxygenase 2 (COX-2) expression is induced by physiological and inflammatory stimuli. Regulation of COX-2 expression is stimulus and cell type specific. Exposure to Zn2+ has been associated with activation of multiple intracellular signaling pathways as well as the induction of COX-2 expression. This study aims to elucidate the role of intracellular signaling pathways in Zn2+-induced COX-2 ...

Transient global ischemia induces a delayed rise in intracellular Zn2+, which may be mediated via glutamate receptor 2 (GluR2)-lacking AMPA receptors (AMPARs), and selective, delayed death of hippocampal CA1 neurons. The molecular mechanisms underlying Zn2+ toxicity in vivo are not well delineated. Here we show the striking finding that intraventricular injection of the high-affinity Zn2+ chela...

1. c-Mannosidase from jack-bean meal was pturified 150-fold. fl-N-Acetylglucosaminidase and f-galactosidase were removed from the preparation by treatment with pyridine. Zn2+ was added during the purification to stabilize the cxmannosidase. 2. At pH values below neutrality, x-mannosidase undergoes reversible spontaneous inactivation at a rate dependent on the temperature, the degree of dilution...

As a selective stress, heavy metals play an important role in inducing the adaptive adjustments of insects to changing environments. Carboxylesterase (CarE) is one kind of biomarker that could help us to explore the adaptation mechanism of aphids to heavy metal stress. In this study, CarE activity and gene expression level were investigated in English grain aphids, Sitobion avenae (F.) (Hemipte...

The molecular basis for substrate translocation in the Na+/Cl--dependent neurotransmitter transporters remains elusive. Here we report novel insight into the translocation mechanism by delineation of an endogenous Zn2+-binding site in the human dopamine transporter (hDAT). In micromolar concentrations, Zn2+ was found to act as a potent, non-competitive blocker of dopamine uptake in COS cells ex...

The Treponema pallidum tro operon encodes an ABC transporter (TroABCD), a transcriptional repressor (TroR), and the essential glycolytic enzyme phosphoglycerate mutase (Gpm). The apparently discordant observations that the solute binding protein (TroA) binds Zn2+, whereas DNA binding by TroR in vitro is Mn2+-dependent, have generated uncertainty regarding the identities of the ligand(s) and co-...

In this study, we investigated the hypothesis that inhibition of the N-methyl-D-aspartate (NMDA) receptor complex by zinc involves a polyamine-sensitive regulatory site. We found that the specific binding of the open channel ligand [3H]MK-801 to rat hippocampal membranes 1) was inhibited by low concentrations of Zn2+ (IC50 = 5.5 microM) by 65%. 2) This high-affinity component of inhibition was ...