The Influence of Selenite on Fillamentous Fungi Hypha Morphometry Parameters

Abstract

Selenium salts have been known for long time to have a potential for both beneficial and harmful effects on living organisms. It is present in the environment, where it can be readily assimilated by plants and fungi, thus entering the food chain. We investigated the cell growth dynamics in the presence of selenite which is considered to have more toxic potential than selenate. The effects of selenite (1 mM) on the growth of fungi from the activated spores to the end of the exponential growth were measured on several hypha morphological parameters by microscopy in vivo. Phycomyces blaekesleneeanus was used as model filamentous fungus. The most striking effect of Se+4 treatment was inhibition of hypha growth, resulting in more than four times shorter hypha in Se+4 –treatment group than in the control (200 ± 50 µm, n = 50 vs 900 ± 100 µm, n = 40 respectively) at the end of exponential growth period under controlled conditions. The Se+4 effect was an inhibition and not a simple delay in growth, as hypha length did not change significantly from 27th to 30th hour of culture in Se+4 -treatment group. Since the microscopy was performed on live cultured cells, undisturbed cytoplasmic streaming was observed, confirming that hyphae were alive at all time points measured. 30h old spore diameters were also significantly reduced by Se+4 treatment (p = 0.0365), while hypha diameters were not significantly altered.