EUKARYOTES: PROTOZOA

Characteristics shared by all protozoa

eukaryotic

unicellular

lack cell walls

free-living; parasitic;

2-20,000 micrometer

moist environment

distribution of protozoa

pleomorphic

throphozoite

cysts

morphology of Protozoa

trophozoite

motile; feeding stage; diagnostic stage

cysts

dormant; resting stage; infective stage; with low metabolic rate

chemoheterotophic

photoautotrophic

Nutrition of Protozoa

chemoheterotrophic

obtain nutrients by phagocytizing bacteria, decaying organic matter, other protozoa, or the tissues of the host; a few absorb nutrients from the surrounding water.

asexually

Binary Fission

(longitudinal BF-flagellated)

(transverse BF- ciliated)

sexually

conjugation (paramecium)

longitudinal BF

flagellated

transverse BF

ciliated

locomotor structures (before)

based on nucleotide sequencing

classification of protozoa is based on their…

Sarcodina

pseudopodia

Mastigophora (flagella)

the largest group in protozoa

Ciliophora

cilia

Sporozoa (nonmotile)

ALL pathogenic to humans

Alveolates

Alveoli (membrane-bound cavities underlying cytoplasmic membrane); tubular mitochondrial cristae

Apicomplexans

Apical complex of organelles

Dinoflagellates

Photosynthesis; two flagella

Alveolates

Ciliates

Apicomplexans

Dinoflagellates

Amoebae

Pseudopodia; lack mitochondria

Amoebae

Foraminifera

Radiolarians

Free- living types

Parasitic types

Parasitic type

Entamoeba

Free- living types

Naegleria

Acanthamoeba

Dinoflagellates

Gymnodinium

Gonyaulax

Pfiesteria

Euglenozoa

flagella; disc- shaped mitochondrial cristae

Euglenoids

Photosynthesis; pellicle

Euglenoids

Euglena

Kinetoplastids

Single large mitochondrion with DNA localized in kinetoplast

Kinetoplastids

Trypanosoma

Euglenozoa

Euglenoids

Kinetoplastids

Diplomonadida

Lack mitochondria, Golgi bodies, and peroxisomes

Diplomonads

Two equal-sized nuclei; multiple flagella

Diplomonads

Giardia

Microsporidia

polar filaments

Diplomonadida

Diplomonads

Microsporidia

Microsporidia

Nosema

Parabasala

Parabasalids

Parabasalids

single nucleus

Parabasalids

Trichonympha

Trichomonas

Alveolates

with small membrane-bound cavities called alvioli

Alveolates

share at least one characteristic-tubular mitochondrial cristae

Ciliates (Balantidium , Paramecium, Stentor, Vorticella, Didinium)

have cilia by which they either move themselves or move water past their cell surfaces

Apicomplexans (Babesia, Plasmodium Toxoplasma, Cryptosporidium)

are all pathogens of animals; the name of this group refers to the complex of special intracellular organelles, located at the apices of the infective stages of these microbes, that enable them to penetrate the host cells.

Felidae

members of the cat family are the only known definitive hosts for the sexual stages of T. gondii and thus are the main reservoirs of infection.

T. gondii

Cats become infected with … by carnivorism

Dinoflagellates (Gymnodinium, Gonyaulax, Pfiesteria)

like many plants and algae their food reserves are starch and oil, and their cells are often strengthened by internal plates of cellulose.

Dinoflagellates (Gymnodinium, Gonyaulax, Pfiesteria)

historically classified as algae because of their plant-like features, taxonomist today note their 18S rRNA sequence and the presence of alvioli indicate that they are more closely related to ciliates and apicomplexans than they are to either plants or algae.

BIOLUMINESCENT

Many dinoflagellates are …; photoautotrophic

dinoflagellate

Peridinium

Red Tide (red pigment)

50,000 cells/ml

a neurotoxin (0.5mg)

Gymnodinium and Gonyaulax

Protozoa in red tide (red pigment)

planktonic dinoflagellates

Ingestion of shell fish (have …)

Possible Estuary-Associated Syndrome

PEAS

Pfiesteria

another toxin (Lois Pfiester)

PEAS (Possible Estuary- Associated Syndrome)

Handling infected fish; breath air laden with the microbes

PEAS (Possible Estuary-Associated Syndrome)

May cause memory loss, confusion, headache, respiratory difficulties, skin rash, muscle cramps, diarrhea, nausea and vomiting.

(Cercozoa) Foraminifera

has a porous shell composed of calcium carbonate arranged on an organic matrix in a snail-like manner.

(Cercozoa) Foraminifera

- pseudopodia extend through the holes in the shell

- lived attached to sand grains on the ocean floor.

- mostly microscopic, though scientist have discovered species several cm in diameter.

Radiolaria

thread-like pseudopodia , have ornate shells of silica; live in marine water as part of the plankton

Radiolaria

the dead bodies of …settle at the bottom of the ocean where they form ooze that is hundreds of meters thick in some locations.

Amoebozoa (Free-living types, Parasitic types)

have a lobed –shaped pseudopodia and no shells

Slime mold

Was formerly considered another group of amoebozoa-to be fungi, but the lobe- shaped pseudopodia by which they feed and move as well as their nucleotide sequences show that they are amoebozoa

plasmodial molds and cellular molds

two types of slime molds

Slime molds

They lack cell walls, more closely resembling amoebae in this regard

Slime molds

They are phagocytic rather than absorptive in their nutrition

morphology, reproduction, and 18SrRNA sequences

Species in the two groups of slime molds differ based on their

Slime molds

are important to humans primarily as excellent laboratory systems for the study of developmental and molecular biology.

Plasmodial (Acellular) Slime Molds (e.g. Physarum)

Exist as streaming, coenocytic, colorful filaments of cytoplasm that creep as amoebae through forest litter, feeding by phagocytizing debris and bacteria.

Cellular Slime Molds (Dictyostelium)

Exist as individual haploid myxamoebae that phagocytize bacteria, yeast, dung, and decaying vegetation.

Euglenozoa

Part of the reason that taxonomist established the Kingdom Protista in the 1960’s was to create a “dumping ground” for euglenids; eukaryotic microbes that share certain characteristics of both plants and animals

Kingdom Euglenozoa

Most recently, based on similar 18S rRNA sequences, the presence of mitochondria with disc-shaped cristae, some taxonomist have created a new taxon: … which include euglenids and some flagellated protozoa called kinetoplastids.

Euglenids

photoautotrophic, unicellular microbes with chloroplasts containing light absorbing pigments-chlorophyll a and b and carotene . It is for this reason that botanist historically classified euglenids in the Kingdom Plantae.

paramylon

One reason for not including euglenids with plants is that euglenids store food as a unique polysaccharide called … instead of starch.

Euglenids

Similar to animals in that they lack cell walls, have flagella, are chemoheterotrophic phagocytes (in the dark) and move by using their flagella as well as by squirming movement which is similar to amoeboid movement but does not involved pseudopodia ( euglenoid movement) .

helical pellicle

Euglenids has flexible, proteinacious, … that underlines its cytoplasmic membrane and helps maintain its shape.

Euglenids

Typically has a “red eye”, which plays a role in positive phototaxis.

Kinetoplastids (Trypanosoma and Leishmania)

have a single large mitochondrion that contains a unique region of mitochondrial DNA called a kinetoplast,

Kinetoplastids (Trypanosoma and Leishmania)

they live within animal, and some are pathogenic.

Diplomonads

lacks mitochondria, golgi apparatus, and peroxisomes.

Biologist once thought these organisms were descended from ancient eukaryotes that had not yet phagocytized the prokaryotic ancestors of mitochondria.

Diplomonads

Geneticist have recently discovered rudimentary mitosomes in the cytoplasm and mitochondrial genes in the nuclear chromosomes, a finding that suggests that diplomonads might be descended from typical eukaryotes that somehow lost their organelles

Parabasala

also lack mitochondria, but each has a single nucleus and a parabasal body, which is a golgi body-like structure.

Trychonympha

Inhabits the gut of termites where it assist in the digestion of wood.