Anomalous cell wall synthesis in Mucor mucedo (L.) FRES. induced by some fungicides and other compounds related to the problem of dimorphism

Abstract

An anomalous cell wall thickening in Mucor mucedo is induced already within 60-120 min by some fungicides (etridiazol, chloroneb, pentachloronitrobenzene, dicloran, drazoxolon, biphenyl) as well as with a N,-atmosphere or high concentrations of glucose, but not with 2,4-dinitrophenol, chlorinated phenols, dichlofluanid and antimycin A. This effect seems to be identical to the change from the rnycelial (M-) to the yeast (Y-) form in dimorphic fungi, which can be achieved by culture conditions as well as by addition of chemicals. The cause seems to be a specific, romplex change in the metabolic state. A scheme of regulation is presented which explains most of the experimental results described till now.-An anonialous cell wall thickening could be observed by electron microscopy in Mucor muceclo under the influence of growth inhibiting concentrations of some fungicides (etridiazol, terrazol, chloroneb and pentachloronitrobenzene (PCNB)) already after 60-120 min (CASPERSON and LYR 1975, 1982, RADZUHN and CASPERSON 1979, WERKER et al. 1979. This resembles very strongly the change from the mycelial (M-) (FISHER 1977). I n order to find a common base for an explanation of the anomalous cell wall synthesis which changes the cell shape, our own results together with the facts described in the literature are discussed and explained by a scheme of regulation. Materials and methodsMucor rnucedo strain P 3 from the collection Institut fur Pflanzenschutzforschung Kleinmachnow was inoculated in 100 ml synthetic glucose asparagin medium (LYR et al. 1975) and cultivated submers on a rotary shaker. The chemicals added to the culture at t h e stage of about 75% germinated spores are dissolved in dimethylformamide (0.8% DMF final concentration in the medium).