Kingdom ProtistaKingdom Protista

ProtistaProtista

• Not a really valid “Kingdom” Not a really valid “Kingdom”

• Grouping is artificialGrouping is artificial

• Few real evolutionary relationshipsFew real evolutionary relationships

• ContainsContains

• Algae: “plant-like” protistsAlgae: “plant-like” protists

• Protozoa: “animal-like” protistsProtozoa: “animal-like” protists

Kingdom ProtistaKingdom Protista

Ch. 26 - Protozoan EmphasisCh. 26 - Protozoan Emphasis

What Are Protists?What Are Protists?

• Junk kingdomJunk kingdom• EukaryoticEukaryotic• Heterotrophic and/or Heterotrophic and/or

autotrophicautotrophic• Single or multicellularSingle or multicellular• Ancestors to animals, Ancestors to animals,

plants, fungiplants, fungi

Animal-like ProtistsAnimal-like Protists

Protozoans• Single celled• Need water in some way

– water, bodies, soil

• Most heterotrophic, some photosynthetic

• Most free-living; some parasitic

All Functions in One CellAll Functions in One Cell

• Eating – food & waste Eating – food & waste vacuolesvacuoles

• Homeostasis – Homeostasis – • Contractile vacuolesContractile vacuoles• Cysts - dormant; harden Cysts - dormant; harden

covering; no metabolic activity. covering; no metabolic activity. (no food, no water, changes in (no food, no water, changes in pH, temp, between hosts)pH, temp, between hosts)

• Movement Movement • Senses – some have light Senses – some have light

sensitive eyespotsensitive eyespot

Amoeba

Paramecium

Plant-like ProtistsPlant-like Protists

Green Algae

Red AlgaeBrown Algae

Golden Algae

- Photosynthesis - No true roots, stems, leaves

Fungi-like ProtistsFungi-like Protists

• Heterotrophic• Decomposers• No cell walls

Slime Molds

Water Molds

ReproductionReproduction

• All reproduce All reproduce ASEXUALLYASEXUALLY• Binary Fission - Binary Fission -

divides into 2 identical divides into 2 identical individuals.individuals.

• Multiple Fission - Multiple Fission - results in a many results in a many identical individualsidentical individuals

Some reproduce Some reproduce SEXUALLYSEXUALLY

ConjugationConjugation - Opposite mating strains pair - Opposite mating strains pair and and exchange genetic material (DNA)exchange genetic material (DNA)

Pond VS. Sewer Water LabPond VS. Sewer Water Lab

• Make wet mounts of both types of waterMake wet mounts of both types of water• Draw organisms and make observationsDraw organisms and make observations

• Hetero or auto?Hetero or auto?• Type of movement?Type of movement?• Protist, protozoan, or other?Protist, protozoan, or other?• Try to find 3 from each type waterTry to find 3 from each type water

• Summarize major differences in critter Summarize major differences in critter type between two water sources.type between two water sources.

Kingdom Kingdom ProtistaProtista

General General CharacteristicsCharacteristics

• EukaryoticEukaryotic• Unicellular (to colonial)Unicellular (to colonial)• Autotrophic or Autotrophic or HeterotrophicHeterotrophic• Appeared about 1.5 BYAAppeared about 1.5 BYA

Classified into Classified into 3 main groups3 main groups

1.1. Animal-like… heterotrophs capable of Animal-like… heterotrophs capable of locomotionlocomotion

2.2. Plant-like… photosynthetic Plant-like… photosynthetic autotrophsautotrophs

3.3. Fungus-like… decomposers that Fungus-like… decomposers that reproduce by sporesreproduce by sporesSome protists may exhibit more than one Some protists may exhibit more than one characteristic, such as...characteristic, such as...…….it is possible to be both animal-like .it is possible to be both animal-like andand plant-like.plant-like.

Animal-like Animal-like ProtistsProtists

(26-2)(26-2)

classified by classified by method of method of movementmovement

Phylum Rhizopoda Phylum Rhizopoda (formerly Sarcodina) : ex. (formerly Sarcodina) : ex. AmoebaAmoeba

The The AmoebaAmoeba uses usespseudopodiapseudopodia for locomotion. for locomotion.

The The AmoebaAmoeba in 3D – notice the in 3D – notice the pseudopodspseudopods

AmoebaAmoeba surround and engulf their surround and engulf their food… the process is called food… the process is called

phagocytosisphagocytosis..

An An AmoebaAmoeba eating a eating a ParameciumParamecium..

CiliophoraCiliophora

• all use cilia for movementall use cilia for movement• have many specialized structures, have many specialized structures,

including mouths, anal pores, contractile including mouths, anal pores, contractile vacuoles, and two nuclei (a large vacuoles, and two nuclei (a large macronucleus and small micronuclei)macronucleus and small micronuclei)

• Ex. – Ex. – ParameciumParamecium and and StentorStentor

Phylum Ciliophora: ex. Phylum Ciliophora: ex. ParameciumParamecium

3D view – taken by a 3D view – taken by a scanningscanning

electron microscopeelectron microscope

A closer look at the Cilia…. A closer look at the Cilia…. its means of locomotionits means of locomotion

another Ciliate: another Ciliate: StentorStentor

Phylum Phylum ZoomastigophoraZoomastigophora

• have flagellahave flagella• some species of some species of

zooflagellates have zooflagellates have mutualistic mutualistic relationshipsrelationships

• ex.- ex.- Trichonympha Trichonympha digests cellulose in digests cellulose in the guts of termitesthe guts of termites

Others are parasites, like Others are parasites, like TrypanosomaTrypanosoma, which causes, which causes

African Sleeping Sickness (coma).African Sleeping Sickness (coma).

TrypanosomaTrypanosoma

TrypanosomaTrypanosoma

Tsetse Fly: carries Trypanosoma to humans; in other words, it’s a Vector

White Blood Cell

Red Blood Cells

Trypanosoma

Phylum SporozoaPhylum Sporozoa• are parasitesare parasites• have no means of locomotionhave no means of locomotion• form spores that are dispersed by form spores that are dispersed by

one or more hosts one or more hosts • ex. ex. PlasmodiumPlasmodium, which causes , which causes

malariamalaria

Portions of the Life Cycle of Portions of the Life Cycle of Plasmodium vivaxPlasmodium vivax

It’s Vector: Anopheles Mosquito

Plasmodium vivax

Red Blood Cells

Phylum ForaminiferaPhylum Foraminifera

• have a protective shell or TEST, usually have a protective shell or TEST, usually made of calcium carbonatemade of calcium carbonate

• layers of tests can deposit on the ocean layers of tests can deposit on the ocean floorfloor• these can form limestone and chalk, like the these can form limestone and chalk, like the

White Cliffs of DoverWhite Cliffs of Dover• Some species of forams are good indicators Some species of forams are good indicators

of oil deposits belowof oil deposits below

Cliffs of Cliffs of DoverDover

Plant-like ProtistsPlant-like Protists

are classified byare classified by

CCOOLLOORR

Phylum ChlorophytaPhylum Chlorophyta

• have both chlorophyll have both chlorophyll aa and and b b (so they are (so they are green)green)

• have cellulose cell wallshave cellulose cell walls• store carbohydrates as starchstore carbohydrates as starch• have many types of sexual reproductionhave many types of sexual reproduction• exhibit many types of organizationexhibit many types of organization

--Are thought to be the ancestors of plants----Are thought to be the ancestors of plants--

Variations in Sexual Variations in Sexual ReproductionReproduction

• Isogamous= both sperm and Isogamous= both sperm and egg are motile and equal in sizeegg are motile and equal in size

• Anisogamous= both sperm and Anisogamous= both sperm and egg are motile and differ in sizeegg are motile and differ in size

• Oogamous= large, nonmotile Oogamous= large, nonmotile egg and small, motile spermegg and small, motile sperm

Variations in Sexual Variations in Sexual ReproductionReproduction

Phylum ChlorophytaPhylum Chlorophytaorganizationorganization

1. Unicellular1. Unicellular

2. Filamentous2. Filamentous

3. Colonial 3. Colonial

4. Bi-layer4. Bi-layer

Unicellular Green Algae Unicellular Green Algae ChlamydomonasChlamydomonas

ChlamydomonasChlamydomonas

Filamentous Green AlgaeFilamentous Green AlgaeSpirogyraSpirogyra

has spiral-shaped chloroplastshas spiral-shaped chloroplasts

another filamentous Green Algae another filamentous Green Algae ZygnemaZygnema

2 Star-shaped chloroplasts per cells2 Star-shaped chloroplasts per cells

a colonial Green Algae … a colonial Green Algae … VolvoxVolvoxMother colony with Daughter Mother colony with Daughter

coloniescolonies

Mother Colony

Daughter Colony

a bi-layered Green Algaea bi-layered Green AlgaeUlvaUlva (sea lettuce) (sea lettuce)

Harvesting UlvaHarvesting Ulva

Phylum Phylum PhaeophytaPhaeophyta

• brown algaebrown algae• multicellularmulticellular• flagellated sperm flagellated sperm

cellscells• Ex.: Ex.: FucusFucus & Kelp & Kelp

Phylum Pheaophyta:Phylum Pheaophyta:Brown Algae… Laminaria.. Brown Algae… Laminaria..

Kelp ?Kelp ?

Air Bladders:Used to take blades to the

surface for PSN

Phylum Rhodophyta:Phylum Rhodophyta:Red AlgaeRed Algae

• are multicellular

• contain red accessory pigments called phycobilins

• gametes do not have flagella

• formerly known as Pyrrophyta or fire algaeformerly known as Pyrrophyta or fire algae• have two flagellahave two flagella• some are bioluminescent, producing lightsome are bioluminescent, producing light• others produce nerve toxinsothers produce nerve toxins

• dinoflagellates are collected and dinoflagellates are collected and concentrated in filter-feeding animalsconcentrated in filter-feeding animals

• people who eat these animals become people who eat these animals become sicksick

Phylum DinoflagellataPhylum Dinoflagellata

Phylum DinoflagellataPhylum Dinoflagellataex. ex. PeridiniumPeridinium

Red Tide- Red Tide- results from a bloom results from a bloom

ofof PeridiniumPeridinium

Phylum Bacillariophyta:Phylum Bacillariophyta: Diatoms… have tests (shells) that Diatoms… have tests (shells) that

contain silica (SiOcontain silica (SiO22), or glass), or glass

Diatom StrewDiatom Strew

Diatoms - a SEM pictureDiatoms - a SEM picture

Phylum EuglenophytaPhylum Euglenophyta

• have one to three flagella at their have one to three flagella at their leading (apical) endleading (apical) end

• have thin protein strips called pellicles have thin protein strips called pellicles wrapped over their membraneswrapped over their membranes

• have an eyespot that permits them to have an eyespot that permits them to swim toward lightswim toward light

• can become heterotrophic when there can become heterotrophic when there is no lightis no light

Euglena Euglena (arrow indicates anterior (arrow indicates anterior end)end)

The Euglena uses a flagella as The Euglena uses a flagella as aa

means of locomotion.means of locomotion.

Phylum Phylum ChrysophytaChrysophyta

• Are golden yellowAre golden yellow• Have one or two apical flagellaHave one or two apical flagella

Phylum Acrasiomycota: Phylum Acrasiomycota: Cellular Slime MoldsCellular Slime Molds

• have both fungus and protist characteristicshave both fungus and protist characteristics• spores germinate into amoebas that feed on spores germinate into amoebas that feed on

bacteriabacteria• When food is depleted, When food is depleted, cyclic AMPcyclic AMP is released, is released,

causing amoebas to aggregate into one unit causing amoebas to aggregate into one unit • the crowd of amoebas form a slug that migratesthe crowd of amoebas form a slug that migrates• cells from the slug form a stalk with a capsule, cells from the slug form a stalk with a capsule,

which makes sporeswhich makes spores• spores are released, and the cycle repeatsspores are released, and the cycle repeats

http://sps.k12.ar.us/massengale/algal__fungal_protist_notes_b1.htm

Acrasiomycota Life CycleAcrasiomycota Life Cycle

Phylum AcrasiomycotaPhylum Acrasiomycotaaggregating aggregating

amoebasamoebascolony &

fruiting body

Phylum Myxomycota: Plasmodial Phylum Myxomycota: Plasmodial Slime MoldsSlime Molds

• grow as a single, spreading mass or plasmodiumgrow as a single, spreading mass or plasmodium• feed on decaying vegetationfeed on decaying vegetation• when the environment becomes unfavorable (no when the environment becomes unfavorable (no

food or water), they form stalks and spore-food or water), they form stalks and spore-producing capsulesproducing capsules

• haploid spores germinate into amoeboid or haploid spores germinate into amoeboid or flagellated cellsflagellated cells

• these cells fuse to form a new diploid these cells fuse to form a new diploid plasmodiumplasmodium

Myxomycota Life CycleMyxomycota Life Cycle

MyxomycotaMyxomycota

http://biodidac.bio.uottawa.ca/ftp/BIODIDAC/Protista/Myxomyco/diagbw/Myxo005b.gif

Phylum OomycotaPhylum Oomycota• are parasitic and saprophyticare parasitic and saprophytic• form filaments, or form filaments, or hyphahyphae (like fungi)e (like fungi)• secrete enzymes into surroundings & secrete enzymes into surroundings &

absorb nutrients (like fungi) absorb nutrients (like fungi) • filaments lack filaments lack septasepta or or cross wallscross walls

resulting in many nuclei in a cell, they are resulting in many nuclei in a cell, they are coenocyticcoenocytic

• have cell walls made of cellulose, not have cell walls made of cellulose, not chitinchitin

http://agronomia.uchile.cl/webcursos/microbiologiagral/pagina%20microbiologia1/micologia/fotos/oomycota.gif

Examples:Examples:• water moldswater molds• downy mildewsdowny mildews• white rustswhite rusts

Oomycota Oomycota Life CycleLife Cycle

http://protist.i.hosei.ac.jp/PDB/Galleries/Klos/Bavaria/Leptomitus_1.html

http://www.anselm.edu/homepage/jpitocch/genbios/28-x2-PowderyMildew.jpg

Phylum OomycotaPhylum Oomycota• potatoes are native to North America potatoes are native to North America • they were introduced to Europe and they were introduced to Europe and

became a staple of the dietbecame a staple of the diet• during the summer of 1846 most of during the summer of 1846 most of

the potato crop was destroyed by the potato crop was destroyed by Phytophthora Phytophthora (an oomycota)(an oomycota)

• nearly 1,000,000 Irish people died, nearly 1,000,000 Irish people died, and 1,500,000 emigrated to other and 1,500,000 emigrated to other countries, like the U.S.countries, like the U.S.

Learning Objective 1Learning Objective 1

• What features are common to the What features are common to the members of kingdom Protista?members of kingdom Protista?

ProtistsProtists

• MostlyMostly unicellular eukaryotic organisms unicellular eukaryotic organisms that live in aquatic environmentsthat live in aquatic environments• There are many that live in soilThere are many that live in soil• Some very important ones are multicellular Some very important ones are multicellular

and are very largeand are very large

Sizes of ProtistsSizes of Protists

• UnicellularUnicellular organisms organisms• microscopicmicroscopic

• ColoniesColonies• loosely connected groups of cells loosely connected groups of cells

• CoenocytesCoenocytes• multinucleate masses of cytoplasm multinucleate masses of cytoplasm

• MulticellularMulticellular organisms organisms• composed of many cellscomposed of many cells• can get very large – some brown algae (the can get very large – some brown algae (the

giant kelps) can be 100 feet in lengthgiant kelps) can be 100 feet in length

KEY CONCEPTSKEY CONCEPTS

• Protists are a diverse group of eukaryotic Protists are a diverse group of eukaryotic organisms, most of which are microscopicorganisms, most of which are microscopic

Learning Objective 2Learning Objective 2

• Discuss in general terms the diversity Discuss in general terms the diversity inherent in the protist kingdominherent in the protist kingdom• means of means of locomotionlocomotion• modes of modes of nutritionnutrition• interactionsinteractions with other organisms with other organisms• habitatshabitats• modes of modes of reproductionreproduction

LocomotionLocomotion

• Protozoa used to be classified according to Protozoa used to be classified according to how they move.how they move.

• Ciliates use fine “hairs” called Ciliates use fine “hairs” called ciliacilia

• Flagellates use longer, whip-like hairs called Flagellates use longer, whip-like hairs called flagellaflagella

• Amoebas and their relatives use Amoebas and their relatives use pseudopodiapseudopodia• Pseudopodia are also used to capture foodPseudopodia are also used to capture food

• Sporozoans (apicomplexans) don’t have any ability Sporozoans (apicomplexans) don’t have any ability to move (to move (non-motilenon-motile))

NutritionNutrition

• Protists obtain their nutrients Protists obtain their nutrients autotrophicallyautotrophically or or heterotrophicallyheterotrophically

ProtistaProtista

• Importance of ProtistsImportance of Protists

• AutotrophicAutotrophic protists = protists = algaealgae

• Photosynthetic algae are the most important Photosynthetic algae are the most important primary producersprimary producers of the world’s freshwater and of the world’s freshwater and marine ecosystemsmarine ecosystems• Many are microscopic Many are microscopic • Some are huge: kelpSome are huge: kelp

• Few cause diseaseFew cause disease• Toxic blooms of dinoflagellates causeToxic blooms of dinoflagellates cause• Red tidesRed tides• shellfish poisoningshellfish poisoning

Diatoms

Giant Kelp

Photosynthetic ProducersPhotosynthetic Producers

6 CO2 + 6H2O 6

C6H12O6

Photosynthesis

Respiration

Energy

Energy

Lake Trophic LevelsLake Trophic Levels

ZooplanktoZooplanktonn

11o o

consumersconsumers

BluegillBluegill22oo

consumerconsumerss

Algae - Algae - producersproducers

BassBass33oo

consumerconsumerss

Osprey Osprey HumansHumans

44oo

consumerconsumerss

Examples of Autotrophic Examples of Autotrophic Protists (Algae)Protists (Algae)

Giant Kelp Forest

Desmids – a type of Desmids – a type of green algaegreen algae

Green and Green and golden algaegolden algae

SummerSummer

TabellariaTabellaria - a diatom Note the - a diatom Note the sheets of rectangular cellssheets of rectangular cells

AsterionellaAsterionella - a diatom - a diatom

DinobryonDinobryon

A chrysophyte algae – Early A chrysophyte algae – Early SpringSpring

Gonyaulax (another flagellate) and view of red tide

ProtistaProtista

• Importance of ProtistsImportance of Protists• HeterotrophicHeterotrophic protists = protists = protozoaprotozoa

• Consume bacteriaConsume bacteria and other protists and other protists• Components of aquatic and soil Components of aquatic and soil food websfood webs• help with help with recycling nutrientsrecycling nutrients

• Some cause Some cause diseasedisease• MalariaMalaria• DysenteryDysentery• Sleeping sicknessSleeping sickness• othersothers

InteractionsInteractions

• Protists are free-living or Protists are free-living or symbioticsymbiotic

• Symbiotic relationships range from Symbiotic relationships range from mutualismmutualism to to parasitismparasitism

Pfiesteria piscicida.

Ulcers on fish caused by Pfiesteria

Note the long flagella

HabitatsHabitats

• Most protists live inMost protists live in• oceanocean• freshwater pondsfreshwater ponds• lakeslakes• StreamsStreams• SoilSoil

• Parasitic protists live in body fluids of Parasitic protists live in body fluids of hostshosts

ReproductionReproduction

• Reproduction Reproduction

• Asexual: Asexual: fissionfission

• Sexual: produce Sexual: produce gametesgametes (specialized sex (specialized sex cells)cells)

• Advantage: new combinations of genesAdvantage: new combinations of genes from both from both parents (Red Queen Hypothesis)parents (Red Queen Hypothesis)

KEY CONCEPTSKEY CONCEPTS

• Protists vary in body plan (unicellular, Protists vary in body plan (unicellular, colonial, coenocytic, multicellular), method colonial, coenocytic, multicellular), method of motility (pseudopodia, cilia, flagella), of motility (pseudopodia, cilia, flagella), nutrition type (autotrophic, heterotrophic), nutrition type (autotrophic, heterotrophic), and mode of reproduction (asexual, and mode of reproduction (asexual, sexual)sexual)

Examples of the ProtozoaExamples of the Protozoa

• About 65,000 speciesAbout 65,000 species• Most are harmless, free-living inhabitants Most are harmless, free-living inhabitants

of water and soilof water and soil• A few are parasitesA few are parasites• Traditionally classified by type of Traditionally classified by type of

locomotionlocomotion• Not correct, but convenient for clinical Not correct, but convenient for clinical

discussionsdiscussions

Classification of Selected Medically Classification of Selected Medically Important ProtozoaImportant Protozoa

• Four groupsFour groups• Mastigophora - flagellatesMastigophora - flagellates• Sarcodina - amoebaeSarcodina - amoebae• Ciliophora - ciliatesCiliophora - ciliates• Apicomplexa – aka SporozoansApicomplexa – aka Sporozoans

• Based on:Based on:• Method of motilityMethod of motility• Mode of reproductionMode of reproduction• Stages in the lifecycleStages in the lifecycle

Styles of LocomotionStyles of Locomotion• All but the Apicomplexa are motile by means of All but the Apicomplexa are motile by means of

pseudopods, flagella, or ciliapseudopods, flagella, or cilia• Some unusual species move by gliding or twistingSome unusual species move by gliding or twisting• PseudopodsPseudopods

• Amoeboid motionAmoeboid motion• Can serve as feeding structuresCan serve as feeding structures

• FlagellaFlagella• From one to severalFrom one to several• Some attached along the length of the cell by the Some attached along the length of the cell by the

undulating membraneundulating membrane• CiliaCilia

• Mostly distributed over the entire surface of the cellMostly distributed over the entire surface of the cell• Form characteristic patternsForm characteristic patterns

Life Cycles Life Cycles

• Vary from simple to complexVary from simple to complex• Two life cycle stagesTwo life cycle stages

• TrophozoiteTrophozoite: feeding stage: feeding stage• Sporozoite Sporozoite (cyst): non-feeding, reproductive(cyst): non-feeding, reproductive

• Some exist only in trophozoite stageSome exist only in trophozoite stage• Others alternate between trophozoite and Others alternate between trophozoite and

cystcyst• Life cycle of a parasitic protozoan Life cycle of a parasitic protozoan

determines the mode of transmission to determines the mode of transmission to hostshosts

Life Cycles and ReproductionLife Cycles and Reproduction

Figure 5.22

Life CyclesLife Cycles

• All reproduce by asexual methodsAll reproduce by asexual methods• Usually mitotic cell divisionUsually mitotic cell division• Some by multiple fission (more than two Some by multiple fission (more than two

daughter cells produced)daughter cells produced)

• Sexual reproduction occurs during the life Sexual reproduction occurs during the life cycle of most protozoacycle of most protozoa

MastigophoraMastigophora (Flagellated) (Flagellated)

• Motility primarily by flagellaMotility primarily by flagella

• Single nucleusSingle nucleus

• Sexual reproduction by syngamySexual reproduction by syngamy

• Division by longitudinal fissionDivision by longitudinal fission

• Parasitic forms tend to lack mitochondria and Parasitic forms tend to lack mitochondria and Golgi apparatusGolgi apparatus

• Most form cysts and are free-livingMost form cysts and are free-living

• Most are solitaryMost are solitary

Figure 5.23

Evolutionary ConsiderationsEvolutionary Considerations

• One group of flagellates, the One group of flagellates, the choanoflagellates, is thought to choanoflagellates, is thought to have given rise to the simplest have given rise to the simplest animals, the sponges.animals, the sponges.

Pathogenic Flagellates: Pathogenic Flagellates: TrypanosomesTrypanosomes

• Giardia lambliaGiardia lamblia• Trichomonas vaginalisTrichomonas vaginalis• Genus Genus TrypanosomaTrypanosoma

• T. bruceiT. brucei causes sleeping sickness causes sleeping sickness• T. cruziT. cruzi causes Chagas disease causes Chagas disease

GiardiaGiardia

GiardiasisGiardiasis• Fecal-oral route of infectionFecal-oral route of infection

• recreational water, water, fomites, contaminated recreational water, water, fomites, contaminated uncooked fooduncooked food

• Symptoms normally begin 1 to 2 weeks (average 7 days) Symptoms normally begin 1 to 2 weeks (average 7 days) after becoming infected.after becoming infected.

• SymptomsSymptoms• Diarrhea Diarrhea • Gas or flatulence Gas or flatulence • Greasy stools that tend to float Greasy stools that tend to float • Stomach or abdominal cramps Stomach or abdominal cramps • Upset stomach or nausea Upset stomach or nausea

• May lead to weight loss and dehydrationMay lead to weight loss and dehydration• Symptoms of giardiasis may last 2 to 6 weeks. Symptoms of giardiasis may last 2 to 6 weeks.

Trichomonas vaginalisTrichomonas vaginalis

A flagellate - causes A flagellate - causes Trichomoniasis, a sexually Trichomoniasis, a sexually transmitted diseasetransmitted disease

TrichomoniasisTrichomoniasis

• STDSTD• Clinical Features:Clinical Features:

• Trichomonas vaginalisTrichomonas vaginalis infection in women is infection in women is frequently symptomatic. frequently symptomatic. 

• Vaginitis with a purulent discharge is the prominent Vaginitis with a purulent discharge is the prominent symptom, and can be accompanied by vulvar and symptom, and can be accompanied by vulvar and cervical lesions, abdominal pain, dysuria and cervical lesions, abdominal pain, dysuria and dyspareunia.  dyspareunia. 

• The incubation period is 5 to 28 days.  The incubation period is 5 to 28 days.  • In men, the infection is frequently asymptomatic; In men, the infection is frequently asymptomatic;

occasionally, urethritis, epididymitis, and prostatitis occasionally, urethritis, epididymitis, and prostatitis can occur. can occur.

Tsetse fly

Trypanosomes Trypanosomes (flagellates) in blood (flagellates) in blood

smearsmear

Kissing bugKissing bug

Tsetse FlyTsetse Fly

25 µm

Flagellum

Red bloodcells

Trypanosomewith undulatingmembrane

Figure 5.27

T. cruzi causes Chagas disease

East Africa West Africa

African Sleeping Sickness

African Sleeping SicknessAfrican Sleeping Sickness

• Bite reaction Bite reaction • Parasitemia Parasitemia

• attacks of fever which starts 2-3 weeks after attacks of fever which starts 2-3 weeks after the bitethe bite

• CNS Stage CNS Stage • changes in character and personality changes in character and personality

• Terminal stage is marked by wasting and Terminal stage is marked by wasting and emaciation emaciation

• Death results from coma, intercurrent Death results from coma, intercurrent infection or cardiac failure infection or cardiac failure

SarcodinaSarcodina (Amoebas) (Amoebas)

• PseudopodsPseudopods• Some have flagellated reproductive statesSome have flagellated reproductive states• Asexual reproduction by fissionAsexual reproduction by fission• Two groups have an external shellTwo groups have an external shell• Mostly uninucleateMostly uninucleate• Usually encystUsually encyst• Most free-livingMost free-living• ExamplesExamples

• EntamoebaEntamoeba• ForaminiferaForaminifera• RadiolariansRadiolarians

Figure 5.24

Infective Amoebas: Infective Amoebas: EntamoebaEntamoeba

• Amoebiasis caused by Amoebiasis caused by Entamoeba Entamoeba histolyticahistolytica

• Fourth most common protozoan infection Fourth most common protozoan infection in the worldin the world

• Aka Aka amoebic dysenteryamoebic dysentery

Figure 5.28

Entamoeba histolytica

Entameoba histolytica

Causes amoebic dysentery (diarrhea) and can enter the liver, lungs, and brain

Naegleria fowleri

Foraminifera

Cyanophora paradoxaCyanophora paradoxa - has no - has no chloroplasts; contains an chloroplasts; contains an endosymbiotic cyanobacterium. endosymbiotic cyanobacterium.

Pelomyxa Pelomyxa has no has no mitochondria; this mitochondria; this amoeba depends on amoeba depends on aerobic bacterial aerobic bacterial symbionts to carry out symbionts to carry out respirationrespiration

More support for the theory: More support for the theory: Living organisms that contain Living organisms that contain endosymbiotic bacteria that carry endosymbiotic bacteria that carry out vital functions in the cell.out vital functions in the cell.

AmoebaeAmoebae

CiliophoraCiliophora (Ciliated) (Ciliated)

• Trophozoites mobile by ciliaTrophozoites mobile by cilia• Some have cilia in tufts for feeding and Some have cilia in tufts for feeding and

attachmentattachment• Most develop cystsMost develop cysts• Both macronuclei and micronucleiBoth macronuclei and micronuclei• Division by transverse fissionDivision by transverse fission• Most have definite mouth and feeding Most have definite mouth and feeding

organelleorganelle• Show relatively advanced behaviorShow relatively advanced behavior• Majority are free-living and harmlessMajority are free-living and harmless

CiliatesCiliates

Balantidium coliBalantidium coli

• Only known ciliate that is pathogenic in humansOnly known ciliate that is pathogenic in humans• Affects humans, other primates, and pigs which Affects humans, other primates, and pigs which

are the reservoir are the reservoir • Lives in the large intestine and causes diarrhea Lives in the large intestine and causes diarrhea • Trophozoites can also be detected in tissue. Trophozoites can also be detected in tissue. • Collect a tissue specimen from the large Collect a tissue specimen from the large

intestine, by sigmoidoscopyintestine, by sigmoidoscopy

TrophozoitesTrophozoites

CystCyst

• Most cases are asymptomatic.  Most cases are asymptomatic.  • Clinical manifestations, when Clinical manifestations, when

present, include persistent diarrhea, present, include persistent diarrhea, occasionally dysentery, abdominal occasionally dysentery, abdominal pain, and weight loss.  pain, and weight loss. 

• Symptoms can be severe in Symptoms can be severe in debilitated persons. debilitated persons.

• Diagnosis is based on detection Diagnosis is based on detection of trophozoites in stool of trophozoites in stool specimens or in tissue collected specimens or in tissue collected during endoscopy. during endoscopy. 

• Repeated stool samples Repeated stool samples • TreatmentTreatment

• Tetracycline with metronidazole Tetracycline with metronidazole and iodoquinol as alternativesand iodoquinol as alternatives

ApicomplexaApicomplexa (Sporozoa) (Sporozoa)

• Most not motile except male gametesMost not motile except male gametes• Complex life cyclesComplex life cycles• Produce Produce sporozoitessporozoites following sexual following sexual

reproductionreproduction• Important in transmission of infectionsImportant in transmission of infections• Most form oocystsMost form oocysts• Entire group is parasiticEntire group is parasitic• ExamplesExamples

• Plasmodium Plasmodium sppspp..• Toxoplasma gondiiToxoplasma gondii• Cryptosporidium parvumCryptosporidium parvum

Mosquito - transmits the malaria Mosquito - transmits the malaria parasite parasite Plasmodium vivaxPlasmodium vivax (a (a sporozoan)sporozoan)

Malaria parasite in Malaria parasite in red blood cellsred blood cells

Parasites breaking Parasites breaking out of red blood cellsout of red blood cells

Malaria

ToxoplasmosisToxoplasmosis

ToxoplasmosisToxoplasmosis• Parasite causes eye and brain damage in a Parasite causes eye and brain damage in a

baby, if untreated. baby, if untreated.

• Acute infection in older children and adults may Acute infection in older children and adults may be without symptoms, cause flu like illness or be without symptoms, cause flu like illness or enlarged lymph glands. enlarged lymph glands.

• Latent parasite occurs very commonly in people Latent parasite occurs very commonly in people infecting approximately a third to a half of all infecting approximately a third to a half of all humans. humans. • Can cause active disease if a person becomes Can cause active disease if a person becomes

immune compromised immune compromised

Protozoan Identification and Protozoan Identification and CultivationCultivation

• Shape and size of cellShape and size of cell• Type, number, and distribution of Type, number, and distribution of

locomotor structureslocomotor structures• Presence of special organelles or cystsPresence of special organelles or cysts• Number of nucleiNumber of nuclei• Can be cultivated on artificial media or in Can be cultivated on artificial media or in

laboratory animalslaboratory animals

Toxoplasma gondiiToxoplasma gondii

• Clinical FeaturesClinical Features::• Generally an asymptomatic or mild self-limiting infection.  Generally an asymptomatic or mild self-limiting infection.  • Immunodeficient patients Immunodeficient patients • brain lesionsbrain lesions• pneumonitispneumonitis

• Pregnant women/infantPregnant women/infant• miscarriage; still birthsmiscarriage; still births• cerebral palsey; seisurescerebral palsey; seisures• mental retardationmental retardation• eye infections; impaired eye infections; impaired

visionvision• enlarged liver and spleen enlarged liver and spleen

Cryptosporidium Cryptosporidium can be a problem in can be a problem in municipal water supplies.municipal water supplies.

Cryptosporidium Cryptosporidium affects affects humans, dogs, and cattlehumans, dogs, and cattle

Cryptosporidium

Intracellular parasite

Causes diarrhea

Affects humans, cattle, sheep, dogs

No effective drug treatment for cryptosporidiosis

Antibiotics are contraindicated; supportive care only

Important Protozoan PathogensImportant Protozoan Pathogens