Reductively activated nitrous oxide reductase reacts directly with substrate.

In the terminal step of bacterial denitrification, N2O is converted to N2 at the mu4-sulfide bridged tetranuclear CuZ center of nitrous oxide reductase. The enzyme can be activated by reduced methyl viologen, with up to a 15-fold increase in specific activity. The reductively activated nitrous oxide reductase from Achromobacter cycloclastes was isolated and characterized by visible absorption and EPR spectroscopy, and both methods showed that the CuZ center can attain a [4Cu(I)] oxidation state.

Comparison of lysis-centrifugation with a biphasic blood culture medium for the recovery of aerobic and facultatively anaerobic bacteria.

The Du Pont Isolator tube and Roche Septi-Chek blood culture bottle employ solid media which facilitate the removal of bacteria from static or cidal substances in blood to increase recovery and decrease detection time. In a comparison of 11,567 blood culture sets, the Isolator tube and vented Roche Septi-Chek bottle were positive for 533 (80%) and 494 (74%) of the aerobic and facultatively anaerobic organisms recovered, respectively. This difference was not significant.

Comparison of the Roche Septi-Chek blood culture bottle with a brain heart infusion biphasic medium bottle and with a tryptic soy broth bottle.

In a comparison of 1,368 positive blood cultures, a vented Roche Septi-Chek (V-RSC) blood culture bottle was superior to an unvented tryptic soy broth-containing bottle (Difco) for the recovery of all aerobic and facultatively anaerobic microorganisms. Anaerobic bacteria were recovered more frequently and earlier in the unvented tryptic soy broth-containing bottle. A separate comparison of 529 positive blood cultures was conducted to examine the performance of the V-RSC bottle with that of a vented brain heart infusion biphasic medium.

Evaluation of media for isolation of Campylobacter fetus subsp. jejuni from fecal specimens.

Isolation rates of Campylobacter fetus subsp. jejuni from human fecal specimens were equivalent after broth enrichment (thioglycolate medium containing antibiotics) and direct inoculation on two brucella blood agar media containing ferrous sulfate, sodium metabisulfite, and sodium pyruvate, identical concentrations of vancomycin and trimethoprim, and different concentrations of polymyxin B and cephalothin. Studies with clinical isolates of C.