Fungi & Antifungals Flashcards
Fungi live in colonies called _
Fungi live in colonies called mycelia
Fungi are connected to each other via _ which are like the arms of the fungus
Fungi are connected to each other via hyphae which are like the arms of the fungus
* Secrete enzymes that help to absorb nutrients from the environment
* Play a role in reproduction
Fungi most commonly reproduce (asexually/ sexually) via mitosis to form _
Fungi most commonly reproduce asexually via mitosis to form spores
* The spores are specialized haploid cells that are optimized for transportation
Fungal spores can also be called _ ; if the hyphae (arms of the fungi) break apart into propagating spores, they are called _
Fungal spores can also be called conidia ; if the hyphae (arms of the fungi) break apart into propagating spores, they are called arthroconidia
We can also have budding off the mature hyphae which is called _
We can also have budding off the mature hyphae which is called blastoconidia
Multicellular spores are called _ and unicellular spores are called _
Multicellular spores are called macroconidia and unicellular spores are called microconidia
Conidia that are enclosed in a sac (sporangium) are called _
Conidia that are enclosed in a sac (sporangium) are called endospores
Spores congregate to form a mass called _
Spores congregate to form a mass called mycelium
Mycelium either form spores and then undergo germination through asexual reproduction, or they can undergo plasmogamy in which nuclei fuse to form a (haploid/ diploid) zygote –> meiosis can then occur
Mycelium either form spores and then undergo germination through asexual reproduction, or they can undergo plasmogamy in which nuclei fuse to form a diploid zygote –> meiosis can then occur (sexual reproduction)
Some fungi are dimorphic, which means _
Some fungi are dimorphic, which means they can exist as unicellular yeast or multicellular molds
* They exist as “mold in the cold” and “yeast in the heat”
In the human body (37 degrees celcius), dimorphic fungi will exist as (mold/ yeast)
In the human body (37 degrees celcius), dimorphic fungi will exist as yeast
* The exception is C albicans
Antifungals that are fungistatic target _ while fungicidal drugs target _
Antifungals that are fungistatic target synthesis of enzymes while fungicidal drugs target cell wall
One of the most important polysaccharides in the thick cell wall of fungi is _
One of the most important polysaccharides in the thick cell wall of fungi is Beta-glucans
The enzyme _ is involved in the production of the beta-glucans and _ is a group of antifungal medications that target this enzyme
The enzyme Beta-1-3- glucan synthase is involved in the production of the beta-glucans and echinocandins is a group of antifungal medications that target this enzyme
Caspofungin, micafungin, anidulafungin
Caspofungin, micafungin, anidulafungin = echinocandins
Certain antibiotics can also be used as (antiprotozoal/ antifungal) medications
Certain antibiotics can also be used as antiprotozoal medications
* We can’t use antibiotics against fungi because fungi are eukaryotes
Humans have cholesterol in the cell membrane phospholipid bilayer; fungi have _
Humans have cholesterol in the cell membrane phospholipid bilayer; fungi have ergosterol
Amphotericin B and nystatin are drugs that bind to _
Amphotericin B and Nystatin are drugs that bind to ergosterol –> pokes holes in the membrane –> causes ions to leak out of the cell
_ is a drug that is known to cause the “shake-and-bake” fever and chills associated with infusion; it also can lead to hypokalemia
Amphotericin B is a drug that is known to cause the “shake-and-bake” fever and chills associated with infusion; it also can lead to hypokalemia
* Sterols in the fungal and human cell membranes look similar; amphotericin can perforate our renal tubual collecting duct –> drops K+
Name the substrates in ergosterol production
Squalene –>
Squalene epoxide –>
Lanosterol –>
Ergosterol
Squalene –> squalene epoxide is catalyzed by _
Squalene –> squalene epoxide is catalyzed by squalene epoxidase
Lanosterol –> ergosterol is catalyzed by _
Lanosterol –> ergosterol is catalyzed by 14-alpha-demethylase
* This is a P450 enzyme
_ is a group of an antifungals that blocks squalene epoxidase
Allylamine is a group of an antifungals that blocks squalene epoxidase
* Includes terbinafine
_ is a group of antifungals that blocks 14-alpha-demethylase
Azoles is a group of antifungals that blocks 14-alpha-demethylase
Ketoconazole can be used for cutaneous dermatophyte infections; however, newer drugs like _ and _ are more commonly used
Ketoconazole can be used for cutaneous dermatophyte infections; however, newer drugs like itraconazole and voriconazole are more commonly used
Oral Ketoconazole is used sparingly because of its side effect profile; it has a hard time differentiating between human _ and fungal _
Oral Ketoconazole is used sparingly because of its side effect profile; it has a hard time differentiating between human liver CYP450 and fungal CYP450
* Leads to a decrease in our cholesterol levels
The antifungal medication flucytosine interupts the synthesis of _
The antifungal medication flucytosine interupts the synthesis of nucleic acids
* Deoxyuridine monophosphate (dUMP) –> deoxythymidine monophosphate (dTMP) via thymidylate synthase
* Fungal cells convert flucytosine –> 5-fluorouracil which inhibits thymidylate synthase
Fungal cells convert flucytosine (antifungal drug) into _ which effectively inhibits _ to halt replication
Fungal cells convert flucytosine (antifungal drug) into 5-FU which effectively inhibits thymidylate synthase to halt replication
* Flucytosine- amphotericin B combo can be used against cryptococcal meningitis but it is otherwise avoided due to toxicity
(Local/ Opportunistic/ Systemic) Fungi are those that are dimorphic fungi found in soil that normally act to decompose organic matter; ingestion of spores can cause illness
Systemic Fungi are those that are dimorphic fungi found in soil that normally act to decompose organic matter; ingestion of spores can cause illness
* Local are usually dermatophytes that attack nails, skin, hair
* Opportunistic are already in our own bodies
_ is native to the southwest region of the US and causes Valley fever
Coccidioides immitis is native to the southwest region of the US and causes Valley fever
_ is transmitted through inhalation of the mold in soil contaminated with bird or bat droppings; it causes pneumonia symptoms and is native to Mississippi and Ohio river valleys (in caves especially)
Histoplasma capsulatum is transmitted through inhalation of the mold in soil contaminated with bird or bat droppings; it causes pneumonia symptoms and is native to Mississippi and Ohio river valleys (in caves especially)
_ causes a systemic granulomatous infection, primarily involving the lungs, following inhalation of the conidia of the dimorphic fungus; it is native to the Mississippi River valley
Blastomyces dermatitidis causes a systemic granulomatous infection, primarily involving the lungs, following inhalation of the conidia of the dimorphic fungus; it is native to the Mississippi River valley
_ is a delayed hypersensitivity reaction to fungal antigens circulating in the bloodstream; occurs from systemic mycoses; painful rash on the shins
Erythema nodosum is a delayed hypersensitivity reaction to fungal antigens circulating in the bloodstream; occurs from systemic mycoses; painful rash on the shins
Granulomas are formed from fibrosis around the fungal infection site due to the signaling of _
Granulomas are formed from fibrosis around the fungal infection site due to the signaling of TNF-alpha
Patients who are taking corticosteroids for asthma are prone to oral thrush; which is the overgrowth of _
Patients who are taking corticosteroids for asthma are prone to oral thrush; which is the overgrowth of Candida
We can use a _ test of scrapings of infected skin, hair, or nail is used to determine the presence of dermatophytes or C albicans
We can use a potassium hydroxide test of scrapings of infected skin, hair, or nail is used to determine the presence of dermatophytes or C albicans
What do we use Sabouraud dextrose agar for?
Sabouraud dextrose agar is a broad use fungal agar that can grow most fungi
A Wood lamp examination uses ultraviolet light to cause _ infection to fluoresce on the skin (an exception to the rule that bacterial but not fungal infections will fluoresce)
A Wood lamp examination uses ultraviolet light to cause microsporum infection to fluoresce on the skin (an exception to the rule that bacterial but not fungal infections will fluoresce)
* Microsporum is the class of dermophytes with tinea capitis, tinia corporis, ringworm
