Lecture 11: Introduction to mycology Flashcards
Moulds divide
sexually or asexually
What is the difference in cell wall between bacteria and moulds
moulds have membrane bound organelles and a cell wall that is not held together by peptide bonds i.e no gram wall
what membrane bound organelles do moulds posess
nucleus, ribosomes through ER, cell wall, mitochondria, vacuole and a cell membrane
how is a mould membrane kept fluid
sterols
What sterol is found in moulds and is targeted with drugs?
ergosterol
What drugs target ergosterol
- amphotericin B and Nystatin bind ergosterol forming pores in the membrane
- Imidazole and allylamine drugs inhibit enzmyes in ergosterol biosynthesis
What is the purpose of antifungal treatment?
target unique features of fungal cells sucha s ergosterol in the cell membrane, glucan cell wall polymer and cytoseine deaminase
how do antifungl agents work on cytoseine deaminase
prevents the conversion of 5-Fluorocytosine to 5-Fluorourcil. this inhibits both protein sythesis and DNA synthesis
Function of Azoles
inhibit ergosterol biosythesis resulting in depletion of this sterol in the cell membrane
Function of polyenes
form pore channels resulting in cell death
Function of candins
inhibit cell wall synthesis, membrane pops - cant cope with osmotic pressure
How do yeasts grow?
divide by budding
Explain the process of budding
- bud begins to form on parent cell
- nucleus copies and divides, the bud receives a copy
- bud now becomes a separate daughter cell
- budding produces chains of cells
What is dimorphic growth as seen with Candida albicans
instead of budding, germ tube or hyphae produced which divide into other cells
____ are the main mode of vegetative fungal growth and are collectively called a ____. yeasts (except C. albicans) are ____ fungi that do not grow as hyphae.
Hyphae, mycelium, unicellular
Yeast cells are ____ to ____ shape and reproduce by ____, any ____ ____ occurs at the junction between mother and daughter cells. Progeny cells detach ____ from mother cells, cosidered ____
round, oval, budding, nuclear, division, completely, unicellular
Hyphal cells are ____, ____-shaped cells where nuclear divsion occurs within ____ ____ cells. This is followed by ____ of one progeny nucelus back into the mother cells. Hyphal cells remain ____ ____ end-to-end, rounds of cell divsion produce multicellular, sparsely branched, filamentous structures called ____ .
thin, tube, daughter cells, migtation, firmly, attached, mycelia
Pseudohyphal cells share features of both ____ and ____. Like hyphae, pseudohyphal cells remain ____ and generate ____ after multiple rounds of cell division. As in yeasts, nuclear divsion in pseudohypahe occurs at ____ to ____ ____; in contrast to hyphae, these junctions are demarcated by visible indentations
yeasts, hypae, attached, mycelia, mother, daughter, junctions
Chalmydospores are ____, ____, thich walled cells observed in vitro under certain harsh condtions such as ____ and ____, Chlamydosproes are generated by ____ cells which are cells at the distal end of mycelial filaments
large, spherical, starvation, hypoxia, suspensor
