Role in anaerobiosis of the isoenzymes for Saccharomyces cerevisiae fumarate reductase encoded by OSM1 and FRDS1.

Saccharomyces cerevisiae possesses both a cytoplasmic and a mitochondrial fumarate reductase, encoded by FRDS1 and OSM1, respectively. While previous studies have shown that mutants lacking FRDS1 and OSM1 cannot grow under anaerobiosis (Arikawa et al., 1998), the physiological role of fumarate reductase (FR) remains poorly understood.

Molecular aspects of the transport and toxicity of ochratoxin a.

Ochratoxins are a class of naturally occurring compounds produced by several fungi. The most toxic is ochratoxin A (OTA), and occurrence of some human nephropathies and tumors correlate with enhanced OTA exposure. In this Account, the following areas are examined: molecular details of the binding of OTA to human serum albumin (HSA), the influences of binding to HSA on the trans-port of OTA across epithelial cell membranes by organic anion transport proteins, the oxidative activation of OTA, and the formation of OTA adducts with biological molecules.

Evidence for covalent DNA adduction by ochratoxin A following chronic exposure to rat and subacute exposure to pig.

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is a potent renal carcinogen in male rats and is suspected of being the etiological agent of Balkan endemic nephropathy (BEN) and its associated urinary tract cancers. Conflicting results have been obtained regarding the genotoxicity of OTA and its ability to react directly with DNA upon oxidative bioactivation to yield covalent DNA adducts. To characterize DNA adduction by OTA, the present study utilizes the photooxidative properties of the toxin to generate authentic C8 OTA-3'-monophosphate-deoxyguanosine (3'-dGMP) adducts for use as cochromatographic standards for (32)P-postlabeling detection of OTA-mediated DNA adduction in the kidney of rat and pig.