Chapter 5: Eukaryotic diversity

UTA Dylan Parks

Why are eukaryotic microbes extremely diverse?

• Different life cycles & reproduction modes

• Many morphologically specialized structures

• Specialized nutritional needs

What are the groups of Eukaryotic microbes?

1. Protozoa

2. Helminths

3. Fungi

4. Algae

5. Lichens

What are protists?

Not plans, animals, or fungi

What is protozoa?

Animal-like; heterotrophic; unicellular

• Water molds and slime molds- fungal like

What is algae?

Plant-like; uni- or multicellular

What is another group of protists?

Plankton

What is plankton?

Microorganisms that drift or float in water, moved by currents

Do protozoa have lots of diversity?

Huge variety found in lots of habitats; good and bad

(not a formal taxa group)

What are the two life stages of protozoa?

Trophozoites and cysts

What happens in the trophozoite stage of protozoa?

Feeding and growth stages

What happens in the cysts stage of protozoa?

Encapsulated stage to protect against harsh environments

What are the types of reproduction protoza can have?

Both asexual and sexual reproduction

How does protoza have asexual reproduction?

Binary fission, budding, or schizogeny

How does protoza have sexual reproduction?

Fusing of haploid gametes (syngamy) or conjugation (but different from bacteria; recall pilus)

What are the cell structures of protozoa?

• Plasmalemma

• Pellicle

What is the cell structure ‘plasmalemma’ in protozoa?

Protozoan membrane

What is the cell structure ‘pellicle’ in protozoa?

Membranes with bands of protein to provide rigidity

How can the shape of the cell structures in protoza be created?

• Outer gel-like layer (ectoplasm)

• Inside fluid in cytoplasm (endoplasm)

What are the two structures of protozoa?

• Cytostome

• Cytoproct

What does the feeding structure ‘cytostome’ do in protozoa?

Taking up food/ nutrients; cilia sweep food towards openings

What two protists does cytostome contain?

Holozoic and saprozoic

What do holozoic protists do?

Take in whole particles

What do saprozoic protists do?

Take in smaller molecules

What does the feeding structure ‘cytoproct’ do in protozoa?

Structure for exocytosis of waste

What are the 3 locomotion structures for protozoa?

1. Flagella

2. Cilia

3. Pseudopodia

What two locomotion structures in protoza are made of microtubules?

Flagella and cilia

What is the locomotion structure ‘pseudopodia’ in protozoa?

Cytoplasmic extensions to attach cell to surface

What are the three prominent groups in protozoa?

1. Amoebozoa

2. Excavata

3. Chromalveolata

What is amoebozoa?

Group of protists that have amoeba-like movement thru pseudopodia

What are the prominent species of amoebozoa?

• Entamoeba histolytica

• Haegleria fowleri

• Acanthameoba spp.

What is Entamoeba histolytica?

Agent for amoebic dysentry

What is Naegleria fowleir?

Causative agent for amoebic meningoencephalitis

What is Acanthameoba spp. ?

Causative agent for keratitis associated with contact lenses

What are the two types of Amoebozoa slime molds?

• Cellular slime molds

• Plasmodial slime molds

What are cellular slime molds?

Individuals can aggregate into a mobile “slug” and creates a fruiting body to produce haploid spores.

What are plasmodial slime molds?

Large amoeboid cells with multiple nuclei; form reproductive stalks to produce spores

What is a common characteristic of Chromalveolata?

Plasmids

What are plasmids?

Membrane bound organelle that often contain photosynthetic pigments

What are the prominent groups of chromalveolata?

• Apicomplexans

• Ciliates

• Oomycetes

• Diatoms

• Dinoflagellates

What two prominent groups of chromalveolata are algae?

Diatoms and diaflagellates

What are chromalveolata?

Apicomeplexans

What are apicomplexans?

• Intra or extracellular parasites

• Apical complex

• Can infect a variety of animals; often transmission between them

What does a apical complex mean?

Concentration of organelles, vacuoles, and microtubules that enable them to establish infection

What is the prominent genera of chromalveolata?

• Plasmodium spp.

• Cryptosporidium parvum

• Babesia microti

• Toxoplasma gondii

What is plasmodium spp. ?

Infect a variety of animal cells; life- cycle between multiple hosts; e.g. malaria and mosquitos

What is Cryptosporidium parvum?

Cysts contaminate drinking water and caused intestinal symptoms

What is Babesia microti?

Transmitted by ticks and blood transfusions; causes potentially fatal recurring fever and hemolysis (babesiosis)

What is Toxoplasma gondii?

Causative agent of toxoplasmosis; transmitted by cat feces, unwashed produce, and undercooked meat

What are ciliates (Used in Chromalveolata) ?

Use cilia for locomotion/ feeding

What is Balantidium coli?

Only pathogenic ciliate

What is Paramecium?

Studied in bio labs

What are oomycetes?

Aka water molds

• Similar to fungi but have cell wals composed of cllulose and are generally diploid

• Phytophthora infestans

What is Phytophthora infestans?

Potato blight

What is a common characteristic of Excavata?

Most have a depression on cell surface (giving its name)

What are some prominent groups of Excavata?

• Fornicata

• Parabasalia

• Euglenozoa

What is Fornicata?

No mitochondria but have flagella

What are the prominent species of Fornicata?

Giardia lamblia

What does Giardia lamblia mean?

Agent for Giardia disease obtained from contaminated waters; cysts are spread via feces

What are Parabasalia?

Common endosymbionts to termites and cockroache

What is the prominent species of parabasalia?

Trichomonas vaginalis

What is Trichomonas vaginalis?

Agent for STD trichomoniasis

What is Euglenozoa?

Photo and non-photosynthetic; generally non-pathogenic with exception:

• Trypanosoma brucei

• Trypanosoma cruzi

What is Trypanosoma brucei?

African sleeping sickness

What is Trypanosoma cruzi?

Chagas diseae

What are Helminths?

• Multicellular parasites

• Larvae and eggs are microscopic

• Round worms (Phylum Nematoda) and flatworms (Phylum Platyhelminthes)

What does multicellular mean?

• Possess organ systems

• Parasites have limited digestive tracts, nervous systems and/or locomotion

• Parasites have complex reproductive cycles and multiple life stages

What are Neotoda phylum (roundworms)?

• >15,000 spp. but not all parasitic

• Unsegmented worms with full digestive systems

• Common parasite to intestines

What are the prominent species of Nematoda phylum?

• Ascaris lumbricoides

• Enterobius vermicularis

• Toxocara spp.

What is Ascaris lumbricoides?

Largest roundworm in humans

What is Enterobius vermicularis?

Most common nematode found in humans

What is Toxocara spp. ?

Common to dogs and cats and transmitted to humans; antibody in 14% of huamns

What are the two parasitic groups for helminths?

1. Flukes (trematodes)

2. Tapeworms (cestodes)

What are flukes (trematodes)?

• Nonsegmented flatworms with oral sucker

• Attaches to lining of intestine, lung or liver

• Schistosoma spp.

What is Schistosoma spp. ?

Causative agent of schistosomiasis; freshwater snails

What are tapeworms (cestodes)?

• Segmented flatworms with sucker/ hooks at the scolex (head region)

• Each section (proglottid) has reproductive structures

• Attaches to small intestines

• Taenia spp.

What is Taenia spp. ?

Beef and pork tapeworm; undercooked/ contaminated meat

What is Fungi?

• Comes in many sizes, shapes and forms

• Heterotrophic and mostly saprophytic

• Mycoses

What is mycoses?

Illness caused by fungi

What are characteristics of molds?

• Multicellular

• Hyphae: Filamentous structures form together into mycelium and thallus (body)

What are characteristics of yeasts?

• Unicellular

• Budding form- asexual reproduction

• Important for much of our food

• Some important pathogens

Where are chitin cell walls?

In fungi and ergosterol in membrane

Is fungi asexual or sexual?

Life cycles can be complex; can be sexual and/or asexual

How many modes can mold have?

Mold can have one or both modes

What is Dimorphic fungi?

Can appear as either yeast or mold

What is the prominent phyla of fungi?

1. Ascomycota

2. Basidiomycota

3. Microsporidia

4. Zygomycota

What is Ascomycota?

• Includes fungi associated with food production, food spoilage, and human pathogens

• Jock itch, athlete’s foot, ringworm

• Bakers’ yeast (Saccharomyces cerevisiae) for making bread and beer

What are the promiennt species of Ascomycota?

• Aspergillus spp.

• Penicillium spp.

• Candida albicans

What is Aspergillus spp. ?

Mold; common cause of allergies and opportunistic infection of tissues

What is Penicillium spp. ?

Mold; producer of antibiotics

What is Candida albicans?

Yeast; normal biota but can be opportunistic pathogen (vaginal yeast infection, oral thrush, candidiasis)

What is Basidiomycota?

• Club-shaped, important decomposer, and food source

• Cryptococcus neoformans

• Amanita phalloides

What is Cryptococcus neoformans?

Yeast that can cause serious lung infections in immunocompromised

What is Amanita phalloides?

Poisonous mushroom known as the death cap

What is microsporidia?

• Unicellular obligate intracellular parasites; once classified as protists

• No mitochondria, peroxisomes, or centrioles

• Polar tubule to pierce host cell and infect

• Many are pathogenic to humans; microsporidiosis

What is zygomycota?

• Mostly saprophytic

• Important for food science

• Common crop pathogens

• Mucor spp.

What is Mucor spp. ?

Necrotizing infections in humans

What is algae?

• Autotrophic protists

• Multicellular or unicellular

• Ecologically and economically important

What are the type of taxa found in algae?

• Chromalveolata

• Archaeplastida

What is chromalveolata?

• Dinoflagellates and stramenopiles

• Mostly marine

• Can be phototrophic, heterotrophic, or mixotrophic

What are dinoflagellates traits?

• 2 flagella - whirl

• Theca- cellulose armor

• Some produce neurotoxins (red tide)

• Paralytic shellfish poisoning