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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
31
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
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