title: Changes in development and ultrastructure of Aspergillus niger mycelium, strain with increased tolerance to toxic substances from beet molasses.
abstract: Effects of a defoamer and toxic molasses compounds on development and ultrastructure of A. niger mycelium, strain Z, characterized by high tolerance to these substances and producing citric acid in surface fermentation on proper molasses media with 70% yield were presented. Spumol BJ in concentration of 5 microliters/100 cm3 as well as toxic molasses compounds stimulated the process of swelling and germinating of conidia. Moreover, giant conidia, unable to germinate, appeared. Developing mycelium with dispersed hyphae became mucilaginous after 17-20 h culture, which indicated the process of sinking but after 24 h some part of the mycelium developed normally. Electron microscopic observations of mycelium developing in the presence of the toxic substances showed along with electron-transparent cytoplasm in a consequence of decrease in ribosome number, changes in ultrastructure of mitochondria. It may be assumed that one of the reasons of the above described abnormalities in development and ultrastructure of mycelium was a disturbance of respiration processes. The appearance of deposits of electron-dense material in mitochondria suggested the existence of a defence mechanism, eliminating toxic substances.
authors.affiliation: Institute of Fermentation Technology and Microbiology, Technical University, Lódź, Poland.
authors.forename: Z
authors.initials: Z
authors.lastname: Zakowska
authors.forename: B
authors.initials: B
authors.lastname: Gabara
mesh_terms: D001234:Aspergillus niger / Q000187:drug effects / Q000254:growth & development* / Q000648:ultrastructure; D003470:Culture Media; D004352:Drug Resistance, Microbial; D008903:Minerals / Q000378:metabolism; D008965:Molasses / Q000633:toxicity*; D013501:Surface-Active Agents / Q000633:toxicity*
chemical_list: D003470:Culture Media; D008903:Minerals; D013501:Surface-Active Agents