Protozoa• ______________ – animal-like protists• 65,000 species• most are ______________ , colonies are rare• vary in shape• lack a cell wall & chloroplasts• Some have a 2-stage life cycle:

– ______________ - motile feeding stage– ______________– a dormant resistant stage

• Many free-living species (have contractile vacuole)

Protozoa – life cycle

Protozoa nutrition

• most are free-living in a moist habitat all are ______________

• feed by engulfing other microbes & organic matter or absorbing through membrane

Reproduction:

• asexual and/or sexual

Locomotion

• most have locomotor structures – – flagella, cilia, or pseudopods

– Some have both flagella and pseudopods

– Some glide or flex

Groups based on locomotion & reproduction

• ______________– flagellates

• ______________– amebas

• ______________– ciliates

• ______________–motility not well developed but some move by gliding/flexing

Mastigophora – flagellates

• Move by flagella, some also have pseudopods

• Usually single nucleus, some have multiple

• Reproduce asexually (mitosis, longitudinal fission) and some sexually (syngamy)

• Most are free-living, cyst-formers

• Some ___________lack certain organelles

• Many parasitic members

7

Figure 5.28

Termite flagellates

• Mutualistic symbiosis

• Digests wood for insect

• ______________

(many flagella!)

Trichonympha

Mastigophora

Giardia lamblia

• Intestinal parasite (______________)

• Characteristic teardrop shape

• 2 nuclei and sucking discs• Multiple flagella and

internal filaments• Spread ______________

______________ • Causes mucus-filled,

flatulent ______________

cyststrophozoites

Mastigophora

Trichomonas vaginalis

• ______________• Has axostyle,

undulating membrane and free flagella

• Parasite of the reproductive tract

• Spread ___________ (trophozoite)

• Frothy, green, purulent discharge

Mastigophora

Men can be asymptomatic carriers.

Leishmania

• Transmitted by insects (sandflies) Infects blood and organs of mammalian host

• Causes a variety of diseases, dependent on species

• Can live ______________

Mastigophora

Trypanosoma species Mastigophora

• Transmitted by insects – Africa (tsetse flies, African Sleeping Sickness); South America (kissing bugs – Chagas’ disease)

• Lives extracellularly (African) and intracellularly (SA )

Sarcodina – amebas

• Locomotion – ______________ , some have flagellated states

• Asexual reproduction – fission

• Some amoebas have a hard shell made of minerals – radiolarians, foraminiferans

• Most are free living

pseudopods

• Can be lobular, blunt, branched, filamentous (long and pointed)

• Cytoplasm flows in pseudopod (ectoplasm)

• Used for feeding, protection and movement

• Results in constantly changing cell shape

Sarcodina

16

Figure 5.29General structure

Sarcodina

Entamoeba histolytica• Causes ______________ -

bloody diarrhea• Can invade extra-intestinal

sites (ulcer systemic)• ______________ found in

fresh feces, host intestine• Old infection or feces –

______________ stage• ______________

transmission

Sarcodina

Sarcodina

Geographic Distribution:Worldwide, with higher incidence of amebiasis in developing countries.  In industrialized countries, risk groups include male homosexuals, travelers and recent immigrants, and institutionalized populations. WHY????

• Use cilia for movement or feeding

• Can have more than one nucleus (macronucleus, micronucleus)

• Feed through a “mouth” like structure (oral groove, ______________ )

• Some reproduce sexually via conjugation – and exchange micronuclei

Ciliophora – ciliates

Basic structure of ciliatesCiliophora

Balantidium coli

trophozoites

cyst

ciliophora

Apicomplexa

• all are ______________

• Trophozoites move by gliding or flexion (see movie) or are non-motile

• Complex life cycles – produce infective stage called ______________

• produce unique reproductive structures (sexual and asexual reproduction)

General structure of

Apicomplexa

Apicomplexa

Malaria

• Caused by ______________ species

• Transmitted by mosquitoes

• Kills ______________ , infects 100-300 M

• Intracellular and extracellular stages

• ______________

Apicomplexa

Toxoplasmosis

• Toxoplasma gondii• Acquired from ________• Causes multiple

symptoms – pregnant women_______________

____________

• Re-emerging disease due to AIDS

• Intra and extracellular stages

Apicomplexa

Cryptosporidium spp.

Modified acid-fast stain of oocysts in fecal smear

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Protozoan ID and culture

• Morphology (cilia, flagella, etc. size, shape, #)

• Location in body (such as presence of cyst or troph in feces)

• Number of nuclei

• May be cultured for additional ID

• Can be cultured in media or with cell/animal model