Fungus

What does heterotroph mean

no photosynthesis

Complete the sentence: Fungi can reporoduce sexually and asexually with the production of **……..**

spores

What is the cell wall of fungi primarily made of?

chitin

Give 2 species of **yeast** of medical importance

1. *Candida albicans*
2. *Cryptococcus neoformans*

Give 2 species of **aseptate** **molds** of medical importance

1\. *Rhizopus sp.*

*2.Mucor sp.*

Give 2 species of **Dematiaceous** **molds** of medical importance

1\.*Rhinocladiella aquaspersa*

2\.*Madurella mycetomatis*

Give 2 species of **Hyaline septate** **molds** of medical importance

1\.aspergillus fumigatous.

2\.aspergillus clavatus

Give 2 species of **Dimorphic molds** of medical importance

1\.histoplasm capsulatum

2\.

Mold are …….. and yeast are …… types of organism

Mold are **multicelllular** and yeast are **unicellular** types of organism

Yeast, mold and dermatophytes are all……?

Saprobes

Describe the clinical manifestations of candidiasis

Caused by species of candida, it can manifest in oral thrush (white paste on tongue), vagina, skin and nails and can rarely invade the body in cases of immunocompromised patients.

What can cryptococcus neoformans cause in immunocompromised

It can be invasive and cause complications such as meningitis and encephalitis

What are the ways in which we can classify fungi?

1. mode of nutrition (saprobes, parasites)
2. mode of reproduction
3. by pathologies caused (cutan, sub-cutan, invasive)
4. phylogenic classification

What are the 5 major groups of fungi?

1. **CHYTRIDIOMYCOTA**
2. **ZYGOMYCOTA**
3. **GLOMEROMYCOTA**
4. **ASCOMYCOTA**
5. **BASIDIOMYCOTA**

Briefly draw the fungi classification tree

What are the clinical manifestations of an **aspergillus** infection?

It can cause localized infections in immunocompetent people, but can cause disseminated infections in immunocompromised patients. It can cause **Allergic BronchoPulmonary Aspergillosis (ABPA) ; sub acute invasive pulmonary aspergillosis, invasive pulmonary apsergillosis** and even more severe like c**erebral aspergillosis and meningitis.** It can also manifest in a chronic way in **Chronic Pulmonary Aspergillosis.**

What are the clinical manifestations of an **fusarium** infection?

It typically causes lesions on the foot such as tinea pedis and pustules in immunocompetent people. In immunocompromised individuals, it can also cause skin lesions and pneumonia, sinusitis.

What is a mycellium?

group of hyphae

What is a dimorphic fungus?

It can live in the soil but can also become a pathogen

What is the difference between **anamorph** and **teleomorph**?

**anamorph**=asexual stage of reproduction

**teleomorph**=sexual stage of reproduction

What are the three types (shapes) of spores?

1\.Ascus (sac-like)

2\.basidium (club-like)

3\.zygospore

Name the 5 families of antifungals

1. Polyenes
2. Echinocandins
3. Azoles
4. Pyrimidine
5. Allyamines

Name a drug from the **polyenes** family

Amphotercin B

Name a drug from the **Echinocandins** family

Caspofungin

Name a drug from the **Azoles** family

Fluconazole

Name a drug from the **Pyrimidine** family

Flucytosine

Name a drug from the **Allyamines** family

Terbinafine

Explain the MOA of **polyenes**

Forms a complex with ergosterol which is found on the cell membrane of the fungus. Leads to the formation of pores leading to a mass leakage of ions (K+)→ death

\
Fungicide on yeasts and filamentous fungi

Explain the MOA of **echinocandins**

Competitive inhibition of 1,3-β-D glucane synthase, leads to the destabilization of the fungal cell wall→ death

Explain the MOA of **Azoles**

Inhibits the conversion of Lanosterol into ergosterol by inhibiting the converting enzyme called 14α-demethylase. This leads to inhibition of ergosterol biosynthesis and therefore the membrane is altered leading to the accumulatoin of toxic methylated sterols→ death

What is an advantage with **echinocandins**?

They are active on biofilms!

Explain the MOA of **Pyrimidines (Flucytosine)**

Flucytosine is converted to the antimetabolite 5-fluorouracil in fungal but not human cells. 5-Fluorouracil inhibits thymidylate synthetase and thus DNA synthesis.

Explain the MOA of **Allyamines**

Inhibition of squalene epoxidase (ERG1) leading to the accumulation of squalene (toxic) and therefore inhibition of ergosterol synthesis→ death

What are some limitations with amphotercin B?

renal toxicity, not absorbed in digestive tract, Induces production of IL-1 & TNF-a, and it has no activity in dermatophytes