Microsporidia, Blastocladiomycota, Neocallimastigomycota

Question 1

What are microsporidia?

Answer 1

single-celled animal parasites

Question 1

What major organelle that most eukaryotes have do Microsporidia lack? what do they have instead?

Answer 1

they do not have mitochondria
instead they have mitosomes

Question 2

What lifestyles do Microsporidia have?

Answer 2

animal endoparasites

Question 3

Where do microsporidia live?

Answer 3

usually in the GI tract of animals but spores can exist outside of host

Question 4

Do Microsporidia typically exhibit both sexual and asexual reproduction?

Answer 4

no, sexual reproduction is rare

Question 5

What are the major features of Microsporidia?

Answer 5

mitosomes instead of mitochondria
polar tubule coils in the sporoplasm and extends to penetrate host cells and push in the sporoplasm to carry contents and infect host

Question 6

What are the economic or ecological implications of microsporidia?

Answer 6

they are emerging disease in humans
they parasitize livestock and other animals

they can be used as biocontrol agents

Question 7

What is an example of Microsporidia?

Answer 7

Nosema apis - the honey bee parasite

Nosema locustae - a biocontrol for locusts and grasshoppers

Question 8

Is it easy to culture Microsporidia?

Answer 8

no because they are obligate endoparasites of animals with specific host ranges

Question 9

What are the defining features of Blastocladiomycota?

Answer 9

they produce motile zoospores and gametes with whiplash flagellum
cell walls have chitin

Question 10

What environments do Blastocladiomycota inhabit?

Answer 10

water and wet soils for active growth
can persist in dry conditions as a resting sporangia

Question 11

What lifestyles do Blastocladiomycota have?

Answer 11

saprophytes
parasites
pathogens of invertebrates and plants

Question 12

What makes the Blastocladiomycota life cycle unique?

Answer 12

it can include alternation of haploid and diploid generations and different generations can have different hosts

sexual reproduction is also common

Question 13

Describe the variations of Blastocladiomycota sporangia morphology

Answer 13

they can be formed from monocentric thalli (single zoosporangium) to polycentric thalli that are filamentous (multiple zoosporangia)

Question 14

What are example species of Blastocladiomycota?

Answer 14

Allomyces arbusculus and Blastocladiella emersonii are model organisms

both saprobes in water or wet soil

Question 15

What structures can Blastocladiomycota have that are unique?

Answer 15

rhizoids to anchor to substrates
pseudosepta (not true septa) in their hyphae

Question 16

What is unique about the lifestyle of phylum Neocallimastigomycota?

Answer 16

they are obligate anaerobes that can exist only in the GI tract of mammalian herbivores - they provide a beneficial service by increasing cellulose digestion and nutrient uptake by the animal

Question 17

How do Neocallimastigomycota break down cellulose and hemi-cellulose in their hosts’ bodies?

Answer 17

they form rhizomycelia to penetrate plant tissue consumed by host and excrete cellulases and other enzymes to break down lignin and cellulose

Question 18

What is an example species of Neocallimastigomycota?

Answer 18

Neocallimatix frontalis

Question 19

Do Neocallimastigomycota have sexual reproduction?

Answer 19

NO only asexual through the production of motile zoospores from sporangia

Question 20

When do Neocallimastigomycota species release zoospores from their sporangia?

Answer 20

in response to food ingestion by the host

Question 21

What major organelle that most other eukaryotes have do Neocallimastigomycota lack? what else? why? what do they have instead?

Answer 21

they don’t have mitochondria or other related structures for the oxidative phosphorylation path because they don’t use oxygen - they are completely anaerobic

they have hydrogenosomes instead for metabolism

Question 22

What biotechnical applications do Neocallimastigomycota have?

Answer 22

probiotics for livestock health

expression of enzymes which break down complex carbon compounds can be useful in food, textile, paper, and biofuel industries

biofuel production - breakdown of lignocellulose and fermentation to produce ethanol