Kategoriak: All - lifecycle - nutrition

arabera Jenny Doriot 16 years ago

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Protozoa

Protozoa are unicellular eukaryotic organisms commonly found in water and soil, forming part of the normal microbiota of animals. They are mostly aerobic chemoheterotrophs, requiring substantial amounts of water for survival.

Protozoa

Protozoa

Nutrition

amoebas phagocytize and digestion is in vacoules--waste out thru anal pore or PM
ciliates wave food to special opening called cytosome
pellicle--special covering
need lots of water
in intestines anaerobic growth
mostly aerobic heterotrophs

Medically Important Phlya of Protozoa

Euglenozoa
hemoflagellates

T. cruzi: Chagas' Disease--"kissing bug" b/c is bites on face

T. brucei gambiense: tsetse fly transmission

Trypansoma: African Sleeping sickness

long slender bodies with undulating membrane

blood parasites

Euglenoids

can photosynthesize

some are facultative chemoheterotrophs

red eye spot to sense light

move by flagellum at anterior end

pellicle

photoautotrophs

Ciliophora
Alveolata

not sure why this info goes here...

same rRna sequences

they all have membrane-bound cavities under the cell surface

ciliates, apicomplexans, and dinoflagellates may be placed here

Balantidium

cysts are ingested by host and enter large intestine

causes severe dysentry

human parasite (only ciliated one)

ciliates--cilia arranged in precise rows
Apicomplexa
Chryptosporidium

respiratory and gall bladder infections

human parasite

Tocoplasma gondii

congenital defects in uetero

trophozoites--called tachyzoites repro sexually and asexually in cat--oocytes w/sporozoites excreted

human parasite from domestic cats

Babesia microti

transmitted by tick

fever and anemia in immunosuppressed

red blood cell parasite

Plasmodium: malaria

human--intermediate host--where asexual stage occurs

mosquito--definitive host--where sexual stage occurs

8. oocytes rupture and send sporozoites to mosquitos saliva---then they bite a human

male and female gametocytes join to form zygote--oocyte formed--divides into asexual sporozoites

7. picked up by bite of another mosquito---enter mos. intestine and begin sexual cycle

6. red blood cells rupture and release merozites...waste products that cause fever are released

5. ring stage enlarges and divides repeatedly

4. young trophozoite look like a ring in which the nucleus and cyto are visible--ring stage

3. merozoites enter bloodstream and infect red blood cells

2. undergo schizogony in liver cells and produce progeny called merozoites

1. sporozite (infect stage) injected into human and carried to liver

sexual reproduction in Anopheles mosquito

complex of special organelles at tip that penetrate host
obligate intracellular parasites
nonmotile in mature form
Amoebozoa
Balamuthia: brain abcesses
Acanthamoeba: in water can cause blindness
E. dispar: nonpath in human and is most common
Entamoeba histolytica: only path. amoeba in humans

lectins attach to galactose on PM and cause cell lysis

move by extending pseudopods
Microspora
obligate intercellular parasites
no microtubules
Archaezoa
Giardia lamblia: small intestine--excreted in feces as cysts--giardiasis
undulating membrane: membrane bordered by flagellum
Trichomonas vaginalis: human parasite
Subtopic
spindle-shaped with front end flagella
symbiontsi n animals
mitosomes instead
eukaryotes that lack mitochondria

General info

malaria 4th leading cause of death
few cause human disease
normal microbiota of animals
trophozite: feeing and growing stage--feed upon bacteria and small particles
water and soil
chemoheterotrophs
eukaryotic
unicellular

Life Cycle

some form gametes
sexual by conjugation: two cells fuse and haploid nucleus from each cell migrate to the other cell. Haploid micronuclei fuse and parent cells separate each now a fertilized cell
schizogony: multiple fission, nucleus undergoes division before cell divides--cyto surrounds the many nuclei then separates
asexually by fission, budding or schiogony

Encystement

oocyst: phylum Apicomplexa--cells produce asexually
cyst allows parasitic species to live outside of hose
protective capsule called cyst