Question

1. Antifungal creams are used for getting rid of the fungal cells without potentially harming the skin. The chemical found in the antifungal cream is most likely to attack which part of the fungal cell? 2. What is the main difference between conidium and sporangiospore in spore production? 3. Describes the main features of the three types of Asocarp.

Answer 1

Answer to question1

Anti-fungals are grouped in 5 categories based on their site of action:

1. Azoles: Inhibit the synthesis of ergosterol which is major sterol in fungal cell membranes. Eg: Clotrimazole, Ketoconazole, Fluconazole
2. Polyenes: bind to fungal membrane sterol (ergosterol) and forms aqueous pores through which cell contents leak out. Eg: Amphoterecin B
3. Allylamines: blocks ergosterol biosynthesis leading to squalene accumulation which proves toxic to cells. Eg: Terbinafine
4. Candins: inhibit the synthesis of beta 1,3-glucan which is a major polymer of the cell wall. This leads to cellular osmotic instability and eventually cell death.
5. Antimetabolites: inhibits macromolecular synthesis by acting as pyrimidine anti-metabolite; inhibits thymidylate synthase; futher disrupts nucleic acid and protein synthesis. Eg: Flucytosine                  There are other anti-fungals like Griseofulvin which is fungistatic in nature, but instead of acting on the cell membrane/ cell wall it acts by disorienting the microtubules during mitosis

So, most of the anti-fungal molecules act on the cell membrane or cell wall of fungus. Since, it is differnt from that of other eukaryotes i.e animal skin cells. This is primarily due to presence of ergosterol and chitin.