chapter 5 eukaryotic diversity

what are the 5 groups of eukaryotic microbes?

1. Protozoa

2. Helminths

3. Fungi

4. Algae

5. Lichens

What are protists?

any eukaryotic organism that is not a plant, animal, or fungi

What are protozoa and what are three examples?

They are animal like, heterotrophic, and unicellular.

Some examples are water molds, plankton, and slime molds, which are fungal like

What are examples of groups of protists?

Protozoa, algae, and plankton

What are algae?

Plant like, uni or multicellular

What are plankton?

microorganisms that drift or float in water, moved by currents

Are protozoa a formal taxa group?

No

What are the two life stages of protozoa?

Trophozoites and cysts

What is the trophozoite stage?

feeding and growth stage

What is the cyst stage?

encapsulated stage to protect against harsh environments

Can reproduction be sexual or asexual in protozoa?

Yes

What is asexual reproduction in protozoa?

binary fission, budding, or schizogony (multiple fission)

What is sexual reproduction in protozoa?

fusing of haploid gametes (syngamy) or conjugation (transfer of genetic material between bacterial cells through direct physical contact, mediated by a structure called a sex pilus)

What are the cell structures of a protozoa?

Plasmalemma: protozoan membrane

Pellicle: membranes with bands of protein to provide rigidness

The shape can be created by an outer gel-like layer (ectoplasm) and inside fluid in the cytoplasm (endoplasm)

What are the feeding structures of protozoa?

Cytostome: takes up food/nutrients, cilia sweep food towards openings

Cytoproct: structure for exocytosis of waste

How do holozoic protists feed?

They take in whole particles

How do saprozoic protists feed?

They take in smaller molecules

What are the locomotion structures of protozoa?

1. Flagella: made of microtubules

2. Cilia: made of microtubules

3. Pseudopodia: cytoplasmic extensions to attach cell to surface

Protozoan taxonomy: what are the prominent groups of protozoa?

Amoebozoa

Excavata

Chromalveolata

Is protozoa polyphyletic?

Yes, ho!

What are amoebozoa?

A group of protists that have amoeba-like movement through pseudopodia

What are prominent species of amoebozoa?

Entamoeba histolytica: agent for amoebic dysentery

Naegleria fowerli: causative agent for amoebic meningoencephalitis

Acanthamoeba spp.: causative agent for keratitis associated with contact lenses

What are cellular slime molds?

individuals that can aggregate into a mobile “slug” and create 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 are chromalveolata

Plastids, which are a membrane bound organelle that often contain photosynthetic pigments

What are prominent groups of chromalveolata?

Apicomplexans

Ciliates

Oomycetes

Diatoms

Dinoflagellates

What are apicomplexans

intra or extracellular parasites

apical complex: concentration of organelles, vacuoles, and microtubules that enable them to establish infection

can infect a variety of animals, often transmission between them

What are some prominent genera of apicomplexans?

Plasmodium spp. infect a variety of animal cells, life cycle between multiple hosts (malaria and mosquitos)

Cryptosporidium parvum: cysts contaminate drinking water and cause intestinal symptoms

Babesia microti: transmitted by ticks and blood transfusions; causes potentially fatal recurring fever and hemolysis (babesiosis)

Toxoplasma gondii: causative agent of toxoplasmosis: transmitted by cat feces, unwashed produce, and undercooked meat

What are ciliates?

A group taht uses cilia for locomotion and feeding

What are examples of ciliates?

Balantidium coli: the only pathogenic ciliate

Paramecium: studied in bio labs

What are oomycetes?

Water molds, similar to fungi but have cell walls composed of cellulose and are generally diploid

What is an example of oomycetes?

Phytophthora infestans: potato blight

What are excavata?

Having a depression on the cell surface

What are prominent groups of excavata?

Fornicata

Parabasalia

Euglenozoa

What are fornicata?

No mitochondria but have flagella

What is a prominent species of fornicata?

Giardia lamblia: an agent for giardia disease obtained from contaminated waters; cysts are spread via feces

What are parabasalia?

Common endosymbionts to termites and cockroaches

What is a prominent species of parabasalia?

Trichomonas vaginalis: an agent for STD trichomoniasis

What is euglenozoa?

Photo and nonphotosynthetic, generally nonpathenogenic, but there are exceptions

What are the exceptions to nonpathenogenic euglenozoa?

Trypanosoma brucei: african sleeping sickness

Trypanosoma cruzi: chagas disease

What are helminths?

multicellular microscopic parasites, possesses organ systens

parasites have limited digestive tracts, nervous systems, and/or locomotion

parasites have complex reproductive cycles and multiple life stages

Why study multicellular parasites?

because their larvae and eggs are microscopic

What are the groups of multicellular parasites?

Roundworms (phylum nematoda)

Flatworms (phylum platyhelminthes)

What is the nematoda phylum?

more than 15,000 species but not all are parasitic.

unsegmented worms with a full digestive system

common parasite to intestines

What are prominent species of nematoda phylum?

Ascaris lumbricoides: largest roundworm in humans

Enterobius vermicularis: most common nematode found in humans

Toxocara spp. common to dogs and cats and transmitted to human, antibody in about 14% of humans

What are the parasitic groups of platyhelminthes phylum?

Flukes (trematodes)

Tapeworms (cestodes)

What are flukes?

nonsegmented flatworms with oral sucker

attaches to lining of intestine, lung, or liver

schistosoma spp. causative agent of schistosomiasis; freshwater snails

What are tapeworms (cestodes)?

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

Each section (proglottid) has reproductive structures

attaches to small intestines

What is an example of tapeworms?

Taenia spp.: beef and pork tapeworm, undercooked/contaminated meat

What are fungi? And what illness does it cause?

They come in many sizes, shapes, and forms

Heterotrophic and mostly saprophytic

Causes mycoses

Chitin cell walls, ergosterol in membrane

Life cycles can be complex, can be sexual and or asexual

Mold can have one or both modes

Dimorphic fungi: can appear as either yeast or mold

What are characteristics of molds (part of fungi)?

Multicellular

Hyphae: filamentous structures that form together into mycelium and thallus (body)

What are characteristics of yeast?

Unicellular

Budding form: asexual reproduction

Important for much of our food

Some important pathogens

What are prominent phyla of fungi?

Ascomycota

Basidiomycota

Microsporidia

Zygomycota

What is ascomycota?

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

Jock itch, athlete’s foot, ringworm

Baker’s yeast (saccharomyces cerevisiae) for making bread and beer

What are the three prominent species of asomycota?

Aspegillus spp.: mold, common cause of allergies and opportunistic infection of tissues

Penicillium spp.: mold, producer of antibiotics

Candida albicans: yeast, normal biota but can be opportunistic pathogen (vaginal yeast infection, oral thrust, candidiasis)

What is basidiomycota?

Club shaped, important decomposer, and food source

What are prominent species of basidiomycota?

Cryptococcus neoformans: yeast that can cause serious lung infections in immunocompromised

Amanita phalloides: poisonous mushroom known as 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 pathenogenic to humans

What are zygomycota?

Mostly saprophytic

Important for food science

Common crop pathogens

What is one example of zygomycota?

Mucor spp.: necrotizing infections in humans

What are algae?

Autotrophic protists

Multicellular or unicellular

Ecologically and economically important

What taxa are algae found in?

Chromoalveolata

Archaeplastida

What are Algae: chromalveolata?

Dinoflagellates and stramenopiles

mostly marine

can be phototrophic, heterotrophic, or mixotrophic

What are dinoflagellates?

2 flagella, whirl

Theca: cellulose armor

Some produce neurotoxins (red tide)

Paralytic shellfish poisoning

What are stramenopiles?

Diatoms (ochraphytes)

• Major produces of oxygen and silicon

• Frustules

• Can become diatomaceous earth

What are red and green algae?

Red algae: cell walls contain agar or carrageenan

Green algae: generally nonpathogenic, important in molecular bio research

What are lichens?

Common soil and rock decomposers

Nonpathenogenic

Many produce important antimicrobials for research

What are lichen made of?

Combo of green algae/cyanobacterium and fungus

Where are lichen found?

terrestrial places

What are the layers to lichen?

1. cortex

2. Algal zone

3. Medulla

4. Lower cortex

5. Rhizines

What are the groups of lichen?

Crustose lichen

Foliose lichen

Fruticose lichen