The regulation of transferrin and iron release from the liver was studied using adult rat hepatocytes in primary monolayer culture. The cells were prelabeled by incubation with rat transferrin doubly labeled with iodine-125 and iron-59. Approximately 50% of the 125I-transferrin but only 10% of the iron-59 taken up by the cells was released during reincubation for 24 h. Less than 10% of the refluxed transferrin was catabolized as indicated by the protein-free iodine-125 values. These results suggest that at least part of iron uptake by hepatocytes is mediated by the reversible binding of transferrin in a manner comparable with erythroid cells and placenta. However, several iron chelators mobilized hepatic iron, in contrast to erythroid cells. Apotransferrin and desferrioxamine released a maximum of about 20% iron-59 with little effect on transferrin binding. A greater proportion of the iron-59 was available for chelation after shorter uptake times (1-2 h) than longer times. Hence, there are at least three iron compartments in hepatocytes in culture: rapidly refluxing iron that may be transferrin bound, a fixed pool, and a chelatable pool that may represent iron in transit between plasma transferrin and ferritin.

A palladium-modified nitrogen-doped titanium oxide (TiON/-PdO) photocatalytic fiber was synthesized on a mesoporous activated carbon fiber template by a sol-gel process. Calcination of the coated fibers resulted in a macroporous interfiber structure and mesoporous photocatalyst coating. Atomic ratios of major photocatalyst constituents determined by X-ray photoelectron spectroscopy analyses were N/Ti approximately equal to 0.1 and Pd/-Ti approximately equal to 0.03. X-ray diffraction analyses revealed that the photocatalyst had an anatase structure and palladium additive was present as PdO. Triplicate batch experiments performed with MS2 phage (average initial concentration of 3 x 10(8) plaque forming units/mL) and TiON/PdO photocatalyst at a dose of 0.1 g/L under dark conditions revealed the occurrence of virus adsorption on the photocatalyst fibers at a rate that resulted in equilibrium within 1 h of contact time with corresponding virion removals of 95.4-96.7%. Subsequent illumination of the dark-equilibrated samples with visible light (wavelengths greater than 400 nm and average intensity of 40 mW/cm2) resulted in additional virus removal of 94.5-98.2% within 1 h of additional contact time. By combining adsorption and visible-light photocatalysis, TiON/PdO fibers reached final virus removal rates of 99.75-99.94%. Spin trapping electron paramagnetic resonance (EPR) measurements confirmed the production of *OH radicals by TiON/PdO under visible light illumination, which provided indirect evidence about MS2 phage being potentially inactivated.

Response surface models of hot, humid air decontamination were developed which may be used to select decontamination parameters for contamination scenarios including aircraft.

Free chlorine is an effective disinfectant for controlling adenoviruses in drinking water, but little is known about the underlying inactivation mechanisms. The objective of this study was to elucidate the molecular components of adenovirus type 2 (Ad2) targeted by free chlorine during the inactivation process. The effects of free chlorine treatment on several Ad2 molecular components and associated life cycle events were compared to its effect on the ability of adenovirus to complete its life cycle, i.e., viability. Free chlorine treatment of Ad2 virions did not impair their ability to interact with monoclonal antibodies specific for hexon and fiber proteins of the Ad2 capsid, as measured by enzyme-linked immunosorbent assays, nor did it impair their interaction with recombinant, purified Coxsackie-adenovirus receptor (CAR) proteins in vitro. Free chlorine-treated Ad2 virions also retained their ability to bind to CAR receptors on A549 cell monolayers, despite being unable to form plaques, suggesting that free chlorine inactivates Ad2 by inhibiting a postbinding event of the Ad2 life cycle. DNA isolated from Ad2 virions that had been inactivated by free chlorine was able to be amplified by PCR, indicating that genome damage was not the cause of inactivation. However, inactivated Ad2 virions were unable to express E1A viral proteins during infection of A549 host cells, as measured by using immunoblotting. Collectively, these results indicate that free chlorine inactivates adenovirus by damaging proteins that govern life cycle processes occurring after host cell attachment, such as endocytosis, endosomal lysis, or nuclear delivery.

Ferrate [Fe(VI); FeO(4)(2-)] is an emerging oxidizing agent capable of controlling chemical and microbial water contaminants. Here, inactivation of MS2 coliphage by Fe(VI) was examined. The inactivation kinetics observed in individual batch experiments was well described by a Chick-Watson model with first-order dependences on disinfectant and infective phage concentrations. The inactivation rate constant k(i) at a Fe(VI) dose of 1.23 mgFe/L (pH 7.0, 25 °C) was 2.27(±0.05) L/(mgFe × min), corresponding to 99.99% inactivation at a Ct of ~4 (mgFe × min)/L. Measured k(i) values were found to increase with increasing applied Fe(VI) dose (0.56-2.24 mgFe/L), increasing temperature (5-30 °C), and decreasing pH conditions (pH 6-11). The Fe(VI) dose effect suggested that an unidentified Fe byproduct also contributed to inactivation. Temperature dependence was characterized by an activation energy of 39(±6) kJ mol(-1), and k(i) increased >50-fold when pH decreased from 11 to 6. The pH effect was quantitatively described by parallel reactions with HFeO(4)(-) and FeO(4)(2-). Mass spectrometry and qRT-PCR analyses demonstrated that both capsid protein and genome damage increased with the extent of inactivation, suggesting that both may contribute to phage inactivation. Capsid protein damage, localized in the two regions containing oxidant-sensitive cysteine residues, and protein cleavage in one of the two regions may facilitate genome damage by increasing Fe(VI) access to the interior of the virion.

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An in chemico high throughput assay based on N-acetylcysteine was developed and used in conjunction with previous and new mammalian cell cytotoxicity data. Our objective was to derive an empirical equation with confidence levels for mammalian cell cytotoxicity prediction. Modeling data included 16 unique sources of waters and wastewaters of distinct water qualities to encompass a wide range of real environmental samples. This approach provides a quick screen to identify those water and wastewaters that could be prioritized for in depth analytical biological analyses and toxicity. The resulting model can serve as a preliminary convenient tool to screen for potential mammalian cell cytotoxicity in organic extracts of a wide variety of water samples.

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