A pseudomonad (CRB5) isolated from a decommissioned wood preservation site reduced toxic chromate [Cr(VI)] to an insoluble Cr(III) precipitate under aerobic and anaerobic conditions. CRB5 tolerated up to 520 mg of Cr(VI) liter ؊1 and reduced chromate in the presence of copper and arsenate. Under anaerobic conditions it also reduced Co(III) and U(VI), partially internalizing each metal. Metal precipitates were also found on the surface of the outer membrane and (sometimes) on a capsule. The results showed that chromate reduction by CRB5 was mediated by a soluble enzyme that was largely contained in the cytoplasm but also found outside of the cells. ). Minor membrane-associated Cr(VI) reduction under anaerobiosis may account for anaerobic reduction of chromate under nongrowth conditions with an organic electron donor present. Chromate reduction under both aerobic and anaerobic conditions may be a detoxification strategy for the bacterium which could be exploited to bioremediate chromate-contaminated or other toxic heavy metal-contaminated environments.

Two types of cold pressor tests were used to study gender differences in cardiovascular and plasma catecholamine responses. Ten male and ten female, young, healthy Caucasian subjects participated. The tests consisted of (1) 5 degrees C air blown at 3.5-4 m/s onto part of the face for 4 min and (2) the open right hand immersed to the wrist in water at 5 degrees C for 4 min. Heart rate, blood pressure (BP), and venous plasma norepinephrine were collected before, during, and 5 min after the 4 min of cold exposures. Test order was decided by a Latin square design, and the subjects rested in a quiet room for 30 min between the two tests. All parameters demonstrated significant (p less than 0.01) increases from rest during the cold tests. Gender differences were significant (p less than 0.01) in diastolic and systolic BP in each test with the males having a greater response, but gender differences were not found in heart rate or norepinephrine concentration. The study demonstrated that gender differences exist in the blood pressure responses to local cold, but that the mechanisms involved do not include a parallel difference in heart rate or venous plasma norepinephrine concentration.