Nep1 Protein from Fusarium oxysporum Enhances Biological Control of Opium Poppy by Pleospora papaveracea.

ABSTRACT The fungus Pleospora papaveracea and Nep1, a phytotoxic protein from Fusarium oxysporum, were evaluated for their biocontrol potential on opium poppy (Papaver somniferum). Four treatments consisting of a control, P. papaveracea conidia, Nep1 (5 mug/ml), and P. papaveracea conidia plus Nep1 (5 mug/ml) were used in detached-leaf and whole-plant studies. Conidia of P. papaveracea remained viable for 38 days when stored at 20 or 4 degrees C. Nep1 was stable in the presence of conidia for 38 days when stored at 4 degrees C or for 28 days at 20 degrees C. The presence of Nep1 did not affect conidia germination or appressoria formation. Nep1 was recovered from drops applied to opium poppy leaves in greenhouse and field studies 24 h after treatment. Opium poppy treated with the combination of Nep1 and P. papaveracea had higher necrosis ratings than the other treatments. There were changes in the intercellular protein profiles, determined by sodium dodecyl sulfate gel electrophoresis and silver staining, due to application of treatments; the most intense occurred in response to the combination of Nep1 and P. papaveracea. The combination of Nep1 and P. papaveracea enhanced the damage caused to opium poppy more than either component alone.

Feasibility of measuring free and total bilirubin electrochemically in serum.

Bilirubin undergoes irreversible reduction at the hanging-mercury-drop electrode in tris(hydroxymethyl)methylamine buffer (0.1 mol/L, pH 8.5). Peak current is linearly related to concentration in the range 0-1 mg/L. The half-wave potential of -1.32 V vs the saturated calomel electrode is little affected by pH, whereas peak current increases with pH to pH 9.5, then decreases rapidly. Exposing the test solution to light causes the peak current to decline at a rate proportional to concentration. Albumin-bound bilirubin is electrochemically inactive, so free bilirubin can be measured in the presence of bilirubin-saturated albumin. Serum total bilirubin can be measured after much of the protein is precipitated by adding methanol. Results for serum bilirubin as measured electrochemically (y) in 20 methanolic filtrates of serum compared well with the Jendrassik-Grof Method (x) in preliminary studies: y = 0.981x -0.311; r = 0.9716. We discuss the possible mechanism of the reduction process and potential clinical applications. Polarographic measurement of bilirubin and bilirubin-binding capacity is feasible and may be advantageous as compared with existing techniques.