Wirkung von Terrazol auf die Ultrastruktur vonMucor mucedo

Abstract

Terrazol, a systemic fungicide showing high specifity to oomycetes, inhibits the apical growth of hyphae and promotes at lower concentrations the thickening of the cell wall in Mucor mucedo. As revealed by ultrastructural analysis, particularly the fine structure of some membrane systems is influenced. In the first place the inner membrane of the mitochondria is attacked leading to a complete lysis of mitochondria. However, the sensitivities within a given population are different. The plasmalemma enlarges, forms several invaginations, partly redraws from the cell wall, but remains intact. Only after an extensive treatment with relatively high concentrations of terrazol the nuclear envelope shows vesicles between the double membranes. The mechanism of action of terrazol is discussed.

An antibiotic produced by Pseudomonas fluorescens CFBP2392 with antifungal activity against Rhizoctonia solani

“…In Mucor mucedo (Zygomycete), a thickening of the cell wall was also observed induced by the fungicides pentachloronitrobenzene (PCNB) and terrazole, although in the latter case it appears to be a non-specific effect reflecting damage to mitochondria ( Casperson and Lyr, 1975 ; Lyr et al, 1977 ). However, in studies carried out with Phytophthora cactorum , PCNB did not cause any deformation of the wall ( Casperson and Lyr, 1975 ).…”

“…In Mucor mucedo (Zygomycete), a thickening of the cell wall was also observed induced by the fungicides pentachloronitrobenzene (PCNB) and terrazole, although in the latter case it appears to be a non-specific effect reflecting damage to mitochondria ( Casperson and Lyr, 1975 ; Lyr et al, 1977 ). However, in studies carried out with Phytophthora cactorum , PCNB did not cause any deformation of the wall ( Casperson and Lyr, 1975 ). Cell wall distortions could not be attributed to the action of the compound purified from P. fluorescens CFBP2392 and thus could be possibly related to the production of other antifungal factors by the bacteria such as hydrolytic exoenzymes.…”

“…After treatment with P. fluorescens CFBP2392, and to a lesser degree with partially purified compound, an increase in glycogen accumulation was observed in the cytosol of R. solani . In a study of the effect of pentachloronitrobenzene (PCNB) on the ultrastructure of Mucor mucedo and Phytophthora cactorum , an increase in vacuole formation was also observed ( Casperson and Lyr, 1975 ). Another effect observed in this work was the appearance of membranous vesicles with unknown granular content.…”

“…In addition, there are two fungicides PCNB and terrazole whose main effect is on mitochondria, as observed by TEM. PCNB causes diffuse lysis of the internal structure of these organelles in Mucor mucedo and Phytophthora cactorum , and also an increase in the perinuclear space ( Casperson and Lyr, 1975 ). In contrast, terrazole attacks the inner membrane of Mucor mucedo mitochondria leading to complete lysis of said organelles.…”

“…In contrast, terrazole attacks the inner membrane of Mucor mucedo mitochondria leading to complete lysis of said organelles. Other affected membranes are the plasma membrane, which elongates and invaginates from the cell wall but remains intact, and the nuclear envelope, which shows vesicles between the membranes ( Casperson and Lyr, 1975 ). The observed effects are induced by a release of phospholipases within mitochondria, and perhaps other membranes.…”