Microsporidia Flashcards
How many described species of microsporidia are there?
around 1,500 species
What type of microorganism is microsporidia
single-celled obligate intra-cellular parasitic eukaryotes (phylogenetically placed in the middle of fungi, but constantly fluxing)
How big is the microsporidia genome?
around 2,000 genes (small!)
Describe the plasma membrane of microsporidia
vesicle or tubule projections increase contact surface area with host
Describe the organelles of microsporidia
one (monokaryon) or two (diplokaryon) nuclei, lots of ribosomes and no mitochondria, but mitosomes, no hyphae.
Describe the structure of microsporidia spores
thick wall, protein and chitin layers, one or two nuclei, wrapped in coiled-up polar filament (extended for infecting host cell)
Describe the life cycle of microsporidia
environmental cues (e.g. osmotic pressure) trigger germination and the polar filament pierces the membrane of the host cells and the sporoplasm/polaroplasms is injected into the host cell.
Decribe horizontal transmission of microsporidia
parasites feeding on infected larvae get infected with microsporidia
Describe the effects of microsporidia infection
can infect a range of tissues, can form cysts (especially in fish) resulting in increased mortality, sex determination in arthropods, more severe pathogenicity in weakened vertebrates.
Describe the transmission of microsporidia
zoonotic, waterborne, airborne, possibly person-to-person, but there’s limited date.
Why is immunity difficult in arthropods?
microsporidia can directly infect hemocytes, as part of the microsporidian life cycle is intacellular.
Describe microsporidiosis in humans
first case in 1959, about a dozen opportunistic species known to infect immuno-compromised individuals, causing intestinal, lung, kidney damage etc.
