Eukaryotic Pathogens: Fungi & Parasites Flashcards
(38 cards)
what are the fungal forms
yeasts, mould & fleshy fungi, Dimorphic fungi
what is yeast
single-celled, reproduce asexually through budding
what is mould and fleshy fungi
long filamentous structures (hyphae
what is dimorphic fungi
grow as either yeast or mould depending on environmental conditions
Blastomyces dermatitidis, Candida spp.
what is the study of fungi
mycology
what ways do fungi reproduce
Fungi reproduce in many different ways
Asexual, sexual or both strategies at different times
what is asexual reproduction
Elongation/fragmentation of hyphae
Budding/division of yeast cells
Production of asexual spores
what is fungi sexual reproduction
Different from that of animals or plants
involves the production of sexual spores
how do fungal infections spread
Fungal infections typically spread by spores
Enter the body through inhalation (typically soil-borne) or damaged skin
Person-to-person contact
Soil (spores) or insects bound with spores.
what are food-based mycotoxins
Secondary toxic metabolites formed by moulds
>200 known mycotoxins
Infects cereals, nuts, figs, spices, coffee, dried fruits
types of food-based mycotoxins
Aflatoxin B1 - produced by Aspergillus Flavus and Parasiticus.
potent carcinogens, associated with liver cancer
Ochratoxin A - produced by Penicillium spp. & Aspergillus spp.
kidney damage in humans & is a potential carcinogen
Patulin - produced by Penicillium spp. & Aspergillus spp.
potentailly carcinogenic, damage immune & nervous system
what are the types of hallucinogenics
Ergot and magic mushrooms
what is ergot
fungus that infects grains of rye & related grasses
Contains lysergic acid alkaloids (LSD precursors) ergotoxine: ergotamine; ergometrine
what is ergotism
afflicted 100,000’s people in Europe during Middle Ages (ingestion of contaminated grain)
Vasoconstriction, gangrene, uterine contractions, nausea, convulsions, seizures, madness, hallucinations, death
what are magic mushrooms
principle active compounds are psilocybin & psilocin
Similar to serotonin
what is algae
- most are aquatic or live in moist conditions
- single or multi-cellular
- Distinct from higher plants as they lack tissue differentiation and are simple plants (no leaves, roots, no connective tissues)
- motile (flagella)
Pathogenic algae
- very few pathogenic
- prototheca spp. colourless algae causes bursitis in joints
- Alexandrium tamarense & Karenia brevis produce a potent neurotoxin which accumulates in shellfish – paralysis if eaten
what is a parasite
An organism that lives in or on the living tissue of a host organism at the
expense of that host
i.e. protozoa & helminths
what is protozoa
Non-photosynthetic, unicellular eukaryotes
Despite uni-cellularity, complex organisation
Pinnacle of unicellular complexity
is paramecium spp. a protozoa
yes
what are the characteristics of protozoa
Cilia – cell motility & sweep food into oral groove
Cell Mouth - where food enters
Anal Pore - disposes of waste
Contractile Vacuole - contracts & forces extra water out of cell
Trichocysts - used for defence
Gullet - forms vacuoles for food storage
Macronucleus - larger nucleus, performs normal cell functions
Micronucleus - smaller nucleus, responsible for cell division
what is Gardia Lamblia
Flagellated protozoan causing thick coating (non-invasive) on Gastrointestinal tract.
Transmitted: F-O-R and Outdoor leisure water.
explosive diarrhea, stomach cramps, upset stomach, bloating & flatulence
loss of appetite, lethargy, fever, gastroenteritis
2/3 people are asymptomatic
what is entamoeba histolytica
Amoeba protozoan causing +/- invasion of GIT.
Transmitted: F-O-R and human reservoir
Three forms
-non-invasive colonisation/invasive form/extraintestinal disease
what is Toxoplasma gondii_ Toxoplamosis
Non-motile parasite
Elaborate lifecycles: cat is definitive host; human intermediate host.
Toxoplasma gondii – toxoplasmosis (from cat faeces)
symptoms:
blindness, hydrocephalus, jaundice, eye lesions & neurological problems
