Effects of antibiotics on fungal cell wall formation
Effects of antibiotics on fungal cell walls have been investigated. Nikkomycin inhibited both hyphal growth and spore germination of Mucor rouxii and Botrytis cinerea. Echinocandin B inhibited hyphal growth and spore germination in B.cinerea. Sporangiospore formation of M.rouxii was affected by Cilofungin. Hyphae of both B.cinerea and M.rouxii extended faster, became fatter and were more susceptible to nikkomycin as the colonies grew older. Those of B.cinerea were also more susceptible to echinocandin B. There was a direct correlation between hyphal extension rate and the square of hyphal diameter in B.cinerea. The mycelial forms of Candida albicans grew as both straight and helical hyphae on the agar medium surface. Straight hyphae also grew under the surface and developed into helices when they grew out of the surface. Straight hyphae extended faster and were more susceptible to Cilofungin than helical hyphae. Hyphae from old colonies of C.albicans were inhibited towards the centre of the plate and this inter-colony effect was overcome by extra medium or by changing positions of inocula. Chitinase activities were detected in homogenates of germinating spores and mycelium in M.rouxii, and were inhibited competitively by allosamidin. This activity was also detected in germinating spores in situ, but different from those in homogenates in response to pH and allosamidin, with the former being tolerant to a wide range of pH and more resistant to inhibition by allosamidin. Allosamidin delayed spore germination of M.rouxii and blocked the continual swelling of germinating spores resulting from the treatment with nikkomycin. Yeast cells of M.rouxii were induced by chloramphenicol with glucose-yeast extract medium. Allosamidin affected the spherical growth of yeast cells, and yeast cells were delayed giving birth to daughter cells. The yeast cell growth rate decreased in the presence of allosamidin.