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The antifungal drug, miconazole nitrate, inhibits the growth of seve'ral species of Candida. Candida albicans, one of the pathogenic species, was totally inhibited at a concentration of approximately 10 jg/ml. Endogenous respiration was unaffected by the drug at a concentration as high as 100 ug/ml, whereas exogenous respiration was markedly sensitive and inhibited to an extent of 85%. The permeability of the cell membrane was changed as evidenced by the leakage of 260-nm absorbing materials, amino acids, proteins, and inorganic cations. The results we present clearly show that the drug alters the cellular permeability, and thus the exogenous respiration becomes sensitive to the drug.Miconazole nitrate [1-(2, 4-dichloro-,-(2, 4-dichlorobenzyloxy)phenethyl)imidazole nitrate] is'a potent antifungal drug (4), the structure of which is shown in Fig.

Nitrate assimilation in many plants, algae, yeasts and bacteria is mediated by two enzymes, nitrate reductase (EC 1.6.6.2) and nitrite reductase (EC 1.7.7.1). They catalyse the stepwise reduction of nitrate to nitrite and nitrite to ammonia respectively. The nitrite reductase from an industrially important yeast, Candida utilis, has been purified to homogeneity. Purified nitrite reductase is a heterodimer and the molecular masses of the two subunits are 58 and 66 kDa. The native enzyme exhibits a molecular mass of 126 kDa as analysed by gel filtration. The identify of the two subunits of nitrite reductase was confirmed by immunoblotting using antibody for Cucurbita pepo leaf nitrite reductase. The presence of two different sized transcripts coding for the two subunits was confirmed by (a) in vitro translation of mRNA from nitrate-induced C. utilis followed by immunoprecipitation of the in vitro translated products with heterologous nitrite reductase antibody and (b) Northern-blot analysis. The 66 kDa subunit is acidic in nature which is probably due to its phosphorylated status. The enzyme is stable over a range of temperatures. Both subunits can catalyse nitrite reduction, and the reconstituted enzyme, at a higher protein concentration, shows an activity similar to that of the purified enzyme. Each of these subunits has been shown to contain a few unique peptides in addition to a large number of common peptides. Reduced Methyl Viologen has been found to be as effective an electron donor as NADPH in the catalytic process, a phenomenon not commonly seen for nitrite reductases from other systems.

Candida spp. grown in synthetic medium supplemented with L-tryptophan as sole nitrogen source produced /B-indoleethanol (/3-IEA) and /3-indolelactic acid (/3-ILA). These compounds isolated from the culture filtrates were characterized by ultraviolet, infrared, and nuclear magnetic resonance spectral studies. Using DL-[3Hltrypotophan in the medium, labeled (3-IEA and /3-ILA were isolated. Further, /3-IEA was produced as a result incubating log-phase cells of C. albicans with /3-ILA. Both (3-IEA and A3-ILA inhibited the growth of grampositive and-negative bacteria. Autoantibiotic action of these compounds on Candida spp. and the reversal of this inhibition were studied. Candida spp. produced f3-phenethylalcohol (5, 7) and its corresponding hydroxy acid, (phenyllactic acid (7). The autoantibiotic action of (-phenethylalcohol has also been reported (5, 6). Production of /8-indoleethanol (tryptophol;

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