MICROBIO Lecture 6 NOTES CONCISE

Vocabulary flashcards summarizing key terms and concepts from the lecture on eukaryotic microbes, fungal biology, symbiosis, disease states, vectors, and protozoan pathogens.

Symbiosis

Any close biological relationship between two different species; outcome can be beneficial, harmful, or neutral.

Parasitism

Symbiotic relationship in which the microbe benefits at the expense of the host; classic disease state.

Commensalism

Symbiosis where the microbe benefits while the host is neither helped nor harmed.

Mutualism

Symbiotic relationship in which both host and microbe benefit.

Neutralism

Hypothetical symbiosis in which neither species is affected; rarely exists in microbiology.

Competition (microbial)

Interaction where two microbial populations vie for space or nutrients; outcome unpredictable.

Predation (microbiology)

Relationship where one organism (e.g., bacteriophage) kills and consumes another microbe.

Bacteriophage

Virus that infects and kills bacteria; studied as a potential alternative to antibiotics.

Diploid

Cell or organism containing two complete sets of chromosomes (2n).

Haploid

Cell or organism with a single set of chromosomes (1n); many fungi survive in this state until fertilization.

Dimorphic Fungus

Fungus able to grow as mold (multicellular) in the environment and as yeast (single-celled) in host tissues.

Mycology

Scientific study of fungi.

Saprophytic

Describes organisms that obtain nutrients from dead organic matter.

Mycorrhizae

Mutualistic association between plant roots and fungal hyphae that increases plant nutrient uptake.

Ascomycetes

Largest fungal phylum; includes yeasts, molds, and all dimorphic pathogenic fungi.

Basidiomycetes

Fungal phylum containing true mushrooms, rusts, and smuts; mostly sexual reproduction.

Zygomycetes

Fungal phylum of multicellular molds such as Rhizopus (black bread mold).

Chytridiomycetes

Aquatic fungi whose motile spores have flagella; rarely pathogenic (frog diseases).

Sporangiospore

Fungal spore produced inside a sac (sporangium) that ruptures to release spores seasonally.

Conidiospore (Conidia)

Asexual fungal spores produced in chains on tips of specialized hyphae without a surrounding sac.

Arthrospore (Arthroconidia)

Fungal spores formed by fragmentation of hyphae; often dispersed by water rather than air.

Hypha (plural Hyphae)

Filamentous, tubular structure composing the body of multicellular fungi.

Vegetative Hyphae

Fungal hyphae specialized for nutrient absorption and growth.

Reproductive (Fertile) Hyphae

Hyphae that produce spores for fungal reproduction.

Rhizoid

Root-like hyphal structure that anchors fungus but normally does not absorb nutrients.

Haustorium

Specialized rhizoid of parasitic fungi that penetrates host cells to obtain nutrients; may require surgical debridement.

Mycelium

Mass of intertwined hyphae forming the visible body of a mold.

Mycosis

Disease caused by a fungus.

Superficial (Dermal) Mycosis

Fungal infection limited to outer surfaces (e.g., athlete’s foot, ringworm).

Subcutaneous Mycosis

Fungal infection beneath the skin, often introduced by trauma (e.g., rose-gardener’s disease).

Systemic Mycosis

Fungal infection that invades internal organs or lungs; usually from dimorphic fungi.

Histoplasma capsulatum

Dimorphic fungus endemic to eastern U.S.; inhaled spores cause histoplasmosis ranging from allergies to pneumonia.

Aspergillus

Common airborne mold; produces aflatoxin and can form invasive lung fungus balls (aspergilloma).

Aflatoxin

Carcinogenic mycotoxin produced by Aspergillus species, common on peanuts and grains.

Aspergilloma (Fungus Ball)

Mass of Aspergillus hyphae that grows in lung cavities; may require surgical removal.

Candida albicans

Yeast normally present as human flora; causes thrush, vaginal yeast infections, and systemic candidemia.

Candida auris

Emerging, multidrug-resistant Candida species designated an urgent CDC threat.

Rhizopus

Genus of black bread mold; can cause pulmonary or rhinocerebral mucormycosis.

Mucormycosis (Zygomycosis)

Severe infection by Zygomycetes (e.g., Rhizopus) often requiring surgical debridement.

Spore

Reproductive, often airborne cell produced by fungi for distribution and survival.

Trophozoite

Active, feeding stage of a protozoan.

Cyst (Protozoan)

Dormant, protective stage of a protozoan enabling survival in harsh conditions.

Mastigophora (Flagellates)

Group of protozoa that move by flagella; includes Giardia and Trichomonas.

Giardia lamblia

Flagellated protozoan causing giardiasis, an oily, malabsorptive traveler’s diarrhea.

Giardiasis

Intestinal disease marked by greasy diarrhea and possible nutrient malabsorption; acquired from contaminated water.

Trichomonas vaginalis

Flagellated protozoan; only protozoan STI; often asymptomatic but can cause purulent discharge and irritation.

Amoeboid Protozoa

Protozoans that move by cytoplasmic streaming (pseudopodia); lack mitochondria.

Entamoeba histolytica

Amoeba causing amoebic dysentery that can progress to liver, lung, or brain abscesses.

Acanthamoeba

Free-living amoeba associated with contact-lens keratitis and potential brain infection.

Naegleria fowleri

Free-living amoeba causing primary amoebic meningoencephalitis after nasal entry from warm freshwater.

Primary Amoebic Encephalitis

Rapid, often fatal brain infection by Naegleria fowleri.

Keratinase

Enzyme produced by dermatophyte fungi to digest keratin in skin, hair, or nails.

Vector (Disease)

Living arthropod that transmits pathogens from one host to another.

Biological Vector

Arthropod in which a pathogen develops or multiplies; transmission requires a blood meal (e.g., mosquito).

Mechanical Vector

Arthropod that physically carries pathogens on body surfaces; no blood meal required (e.g., housefly).

Haustorial Infection Debridement

Surgical removal of fungal tissue embedded by haustoria to fully eliminate infection.

Immunosuppression

Deliberate or disease-induced reduction of immune function; major risk factor for systemic mycoses.

Allergic Hypersensitivity to Spores

Immune reaction to high seasonal fungal spore counts causing rhinitis or asthma.

Ergot (Claviceps purpurea)

Hallucinogenic mycotoxin contaminating rye; source of vasoconstrictor drug ergotamine.

Statins

Cholesterol-lowering drugs originally derived from fungal metabolites.

Cyclosporine

Immunosuppressant drug derived from fungi, critical for organ transplantation.

Penicillin

First widely used antibiotic, produced by the mold Penicillium.

Cephalosporins

Broad class of beta-lactam antibiotics originally isolated from fungi.

Fungal Dimorphism Trigger

Shift from mold to yeast driven by higher temperature, low nutrients, and low oxygen inside host.

Spore Count

Number of airborne fungal spores per cubic meter; can reach 10,000 during peak seasons.

Thrush

Oral Candida infection characterized by white curd-like plaques.

Aspergillosis

Disease spectrum from allergic reactions to invasive lung infection by Aspergillus species.

Fungus Ball (Mycetoma) in Brain

Severe invasive aspergillosis forming a mass inside cerebral tissue.

Rhinocerebral Mucormycosis

Aggressive Zygomycete infection of sinuses and brain, common in diabetics and trauma patients.

Fungal Spores vs. Bacterial Endospores

Fungal spores are reproductive units produced in large numbers; bacterial endospores are single survival structures.

Haemolytic Fungus Amanita

Genus producing deadly amatoxins; single mushroom cap can cause fatal liver failure.

Amoebic Dysentery

Bloody diarrhea caused by tissue-invasive Entamoeba histolytica.

Traveler’s Diarrhea Prevention

Avoid untreated water and raw produce to reduce risk of Giardia infection.

Contact Lens Hygiene

Proper cleaning prevents Acanthamoeba keratitis.

Haemolytic Fungal Toxin

Substance produced by certain mushrooms that destroys liver cells (e.g., amatoxin).

Vector-Borne Seriousness

Diseases from biological vectors tend to be more severe than those from mechanical vectors.