The cytotoxicity of the bacterial toxin colicin E9 is due to a non-specific DNase that penetrates the cytoplasm of the infected organism and causes cell death. We report the first enzymological characterization of the overexpressed and purified 15 kDa DNase domain (E9 DNase) from this class of toxin. CD spectroscopy shows the E9 DNase to be structured in solution, and analytical ultracentrifuga...

Upon contact with allergen, sensitized mast cells release highly active proinflammatory mediators. Allergen-mediated mast cell activation is an important mechanism in the pathogenesis of atopic asthma. Asthmatic patients are especially susceptible to air pollution. Epidemiologic studies found a positive correlation between severity of symptoms among asthmatic patients and the level of particula...

All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Extremely acidophilic microorganisms have an optimum growth of pH <3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles ...

1. When iron and copper are allowed to act on hydrogen peroxide and pyrogallol, enough carbon dioxide is produced to be readily measured. 2. The curve of the production of carbon dioxide may be fitted by an empirical equation, by the use of which the initial rate and the total amount of the oxidation may be determined. 3. The effect of the concentration of the reagents is different in each case...

The etiology of Alzheimer's Disease (AD) is multifactorial. It has been suggested that transition metals such as copper (Cu) and iron (Fe) as well as aluminum (Al) may be involved in the pathogenesis of the disorder. While Cu and Fe are redox-active, Al only exists in the trivalent form and is redox-inert. We previously demonstrated that Al exposure causes an increase in inflammatory parameters...

A large fraction of the trace metal pool in estuarine and coastal waters is complexed with colloidal-sized macromolecular organic matter. Bioaccumulation and bioavailability studies of trace metals have generally utilized freeionic dissolved metal ions. Consequently, little is known about the uptake and depuration kinetics of the colloidally bound species. Chemical characteristics such as the r...

The human dopamine transporter (DAT) has a tetrahedral Zn2+-binding site. Zn2+-binding sites are also recognized by other first-row transition metals. Excessive accumulation of manganese or of copper can lead to parkinsonism because of dopamine deficiency. Accordingly, we examined the effect of Mn2+, Co2+, Ni2+, and Cu2+ on transport-associated currents through DAT and DAT-H193K, a mutant with ...

A key challenge to the exploration of electrochemical energy conversion and storage is the ability to engineer the catalyst with low cost, high activity and high stability. Existing catalysts often contain a high percentage of noble metals such as Pt and Pd. One important approach to this challenge involves alloying noble metals with other transition metals in the form of a nanoalloy, which pro...

Trace levels of transition metals can participate in the metal-catalyzed Haber-Weiss reaction (superoxide-driven Fenton reaction) as well as catalyze the oxidation of ascorbate. Generally ascorbate is thought of as an excellent reducing agent; it is able to serve as a donor antioxidant in free radical-mediated oxidation processes. However, as a reducing agent it is also able to reduce redox-act...