L40_Fungi-1 Flashcards

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1
Q

Bacteria are prokaryotes, what are fungi?

A

They are eukaryotic heterotrophs like humans

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2
Q

Why dont anti-bacterials have any efficacy against fungus?

A

Because most antibacterials are targets agains 70s ribosomes or the production of peptidoglycan

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3
Q

What are fungal walls made of?

A

Chitin and Beta-Glucan

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4
Q

What are the two major targets of antifungals?

A

beta-glucan and ergosterol (cholesterol analog of fungal membranes)

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5
Q

With respect to toxicity, describe why designing antibiotics is much harder for fungi

A

Antifungals usually have some toxicity in humans, there are fewer molecular targets and since fungi and humans have a much closer evolutionary relationship with humans the effects of antifungals have a lot of spill over into the human system.

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6
Q

Describe fungi ability to grow in different environments than bacteria

A

Fungi can grow in drier, higher-osmotic-pressure, and colder environments than bacteria: more cutaneous infections and food spoilage.

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7
Q

What are the two main types of fungi, how do each reproduce?

A

Two main types of fungi: yeast are single-celled, reproduce by budding; molds grow in hyphae/mycelia and have complex reproduction. Both make new cells by fungal mitosis; yeast and some others have closed mitosis.

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8
Q

What certain type of fungi have spores that can be directly diagnosed via microscopy?

A

Five types of asexual spores have distinctive microscopic appearances that may be used for diagnosis.

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9
Q

What is thermal dimorphism?

A

Thermal dimorphism: several important fungal pathogens grow as mold at 24C and as yeast at 37C. Yeast form has more immune-evasive properties; dual cultures can be useful for diagnosis.

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10
Q

What is the typical results of an immune response to fungi?

A

Immune response to fungal infection is granulomatous, sometimes also suppurative.

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11
Q

What are the consequences of most fungal pathogens being environmental?

A

Most fungal pathogens are environmental: little contagion or drug resistance, no eradication

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12
Q

What fungi is a normal flora?

A

Exception: C. albicans yeast is normal flora / opportunistic pathogen

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13
Q

What is mycotoxicosis caused by?

A

Mycotoxicosis is caused by eating fungal toxins (wrong mushroom or spoiled food); not fungal infection.

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14
Q

Can people have allergies to fungus?

A

Fungal allergies can also be dangerous (asthmatic reaction) `

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15
Q

How can fungal infections be diagnosed?

A

Fungal infection diagnosed by PPD, KOH-mount microscopy with fungal stains, culture on Sabouraud’s agar; PCR available for dangerous systemics; serology for epidemiology.

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16
Q

What are the major classes of antifungals?

A

Polyenes, Azoles, Echinocandins

17
Q

What do polyenes target, what are their side effects? what is the major one?

A

Polyenes are highly effective and broad-spectrum but toxic – Amphotericin B is the only systemic and is nephrotoxic (can be used during pregnancy

18
Q

What do Azoles target, what is one of the main ones, what species does it kill?

A

Azoles are less toxic and inhibit ergosterol synthesis; different ones optimally active against different fungi; Fluconazole/Diflucan major one, treats candidiasis and cryptococcosis

19
Q

What do Echinocandins target, what are they highly effective against?

A

Echinocandins are low-toxicity and inhibit beta-glucan syn , highly effective against candida and aspergillus (both are opportunistic pathogens)