Abstract | Crystals of the polyene antibiotics amphotericin B, candicidin, candidin, and nystatin placed on the hyphae of Pythium sp. PRL 2142 induce the formation of many oogonia. Candidin incorporated into agar plates, at a concentration of 1000 μg/ml, promotes abundant oospore production which can be completely inhibited by 5 μg/ml of cholesterol. Conversely, cholesterol by itself, at 4 g per kilogram dry mycelium stimulates oogonial formation which can be inhibited by the antibiotics listed above. Filipin induces the formation of only one or two oogonia and causes lysis of the mycelium growing in the presence of cholesterol. Amphotericin B increases slightly the mycelial yield of cholesterol-grown mycelium. High concentrations of filipin and amphotericin B increase the dry weight of mycelium growing in the absence of sterol. |
---|