Microbiology UTA 2460 Chapter 5

Eukaryotic Microbes

-extremely diverse

-different life cycles & reproduction modes

-many morphologically specialized structures

-specialized nutritional needs

Groups of Eukaryotic Microbes

1.Protozoa

2.Helminths

3.Fungi

4.Algae

5.Lichens

Protists

-not plants, animals, or fungi

-Protozoa (animal-like, heterotrophic, unicellular)

-Algae (plant-like, uni/multicellular)

-Plankton (microorgs that drift or float in water, moved by currents)

zooplankton

motile, nonphotosynthetic

phytoplankton

photosynthetic

protozoa

-Huge variety of unicellular, non-photosynthetic, motile eukaryotic microbes

(Not a formal taxa group)

-Reproduction can be sexual or asexual

Asexual

-binary fission

-budding

-schizogeny(nuclues divides multiple time)

Sexual

-fusing of haploid gametes (syngamy) or conjugation

Two life stages of protozoa

1. Trophozoites - feeding & growth stages

2. Cysts - encapsulated stage to protect against harsh environments

Cell structures of Protozoa

-Plasmalemma: protozoan membrane

-Pellicle: membranes with bands of protein to provide rigidness

-Shape can also be created by outer gel-like layer (ectoplasm) and inside fluid in cytoplasm (endoplasm)

Feeding structures of Protozoa

-Cytostome: taking up food/nutrients (Cilia sweep food towards openings)

-Holozoic protists: take in whole particles

-Saprozoic protists: take in smaller molecules

-Cytoproct: structure for exocytosis of waste

Locomotion structures of Protozoa

-cilia

-flagella

-pseudopodia (cytoplasmic extensions to attach cell to surface)

Unique Organelles of Protozoa

-Contractile vacuoles (help regulate osmotic pressure)

Mitochondria may be absent or modified:

-Kinetoplastid (DNA bundles located by basal body of flagella)

-Hydrogenosomes (to produce ATP without O2)

Protozoan Taxonomy

-polyphyletic (lack shared evolutionary origin)

-groups: amoebozoa, excavata, chromalveolata

Protozoan group: Amoebozoa

Group of protists that have amoeba-like movement thru pseudopodia. Actin microfilament produce pseudopodia and reminder helps move organisms.

Entamoeba histolytica (Amoebozoa)

transmitted by cysts and feces. agent for amoebic dysentery. bloody diarrhea

Naegleria fowleri (Amoebozoa)

-causative agent for amoebic meningoencephalitis

-brain eating

-fatal

-through the nose

Acanthameoba spp. (Amoebozoa)

causative agent for keratitis associated with contact lenses leads to blindness

Slime Molds of Amoebozoa

-cellular slime molds: individuals can aggregate into a mobile "slug" and creates a fruiting body to produce haploid spores

-plasmodial slime molds: large amoeboid cells with multiple nuclei; form reproductive stalks to produce spores

Protozoan group: Chromalveolata

prominent groups: Apicomplexans, Ciliates, Oomycetes, Diatoms, Dinoflagellates

Common characteristic of chromalveolata

Plastids - membrane bound organelle that often contain photosynthetic pigments

Chromeoveolata: Apicomplexans

-intra or extracellular parasites

-apical complex (concentration of organelles/vac./tubules that enable them to cause infection)

-life cyle (infective sporozoites undergo schizogeny)

Plasmodium spp. (Apicomplexans)

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

Cryptosporidium parvum (Apicomplexans)

cysts contaminate drinking water and caused intestinal symptoms. GI tract, resistant to chlorine

Babesia microti (Apicomplexans)

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

Toxoplasma gondii (Apicomplexans)

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

Chromalveolata: Ciliates

-use cilia for locomotion and feeding

-ability to reproduce via conjugation

Balantidium coli (Ciliates)

only pathogenic ciliate. interstinal illness

Paramecium (Ciliates)

studied in bio labs. well known

Chromalveolata: Oomycetes

-"water molds"

-similar to fungi, but have cellulose cell walls

-generally diploid

Phytophthorainfestans (Oomycete)

potato blight. mass death. irish population

Protozoan group: Excavata

-most have a depression on cell surface

-prominent groups: Fornicata, Parabasalia, Euglenozoa

Fornicata (excavata)

no mitochondria but have flagella

Prominent species of fornicata (excavata)

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

Parabasalia (excavata)

-common endosymbionts to termites and cockroaches

-Have modified mitochondria (kinetoplast)

Prominent species of parabasilia (excavata)

Trichomonas vaginalis- agent for STD trichomoniasis. complications in pregnancy

Euglenozoa (excavata)

-photo and non photo synthetic

-cell have 2 flagella, a stigma (eyespot), and chloroplast

-generally non pathogenic *exception genus Trypanosoma

Genus Trypanosoma (euglenozoa)

exception to euglenozoa, pathogenic

- agent for African sleeping sickness(tsetse fly) and Chagas disease(American)

helminths

-Multicellular (possess organ systems) parasitic worms

-larvae and eggs are microscopic

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

-Parasites have complex reproductive cycles and multiple life stages

Monoecious

both male and female organs in the same individual/organism

Dioecious

either male or female in separate individuals

Prominent groups of helminths

-roundworms (phylum Nematoda)

-flatworms (phylum platyhelminthes)

Helminths: Nematoda phylum (roundworms)

- >15,000 spp. but not all parasitic

-Unsegmented worms with full digestive system

-Common parasite to intestines

Ascaris lumbricoides (roundworms)

largest roundworm in humans

Enterobius vermicularis (roundworms)

-"pin worm"

-most common nematode found in humans

Toxocara spp. (roundworms)

- common to dogs & cats and transmitted to human

- antibody in ~14% of humans

Helminths: Platyhelminthes phylum (flatworms)

Parasitic groups:

1.Flukes (trematodes) 2.Tapeworms (cestodes)

Flukes (trematodes)

-nonsegmented flatworms with oral sucker

-attaches to lining of intestine, lung, or liver

Prominent species of Flukes (trematodes)

Schistosoma spp.- causative agent of schistosomiasis; freshwater snails

Tapeworms (cestodes)

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

-Each section (proglottid) has reproductive structures

-Attach to small intestines

Prominent species of Tapeworms (cestodes)

Taenia spp.- beef and pork tapeworm; undercooked/ contaminated meat

Fungi(yeast and mold)

-Comes in many sizes, shapes, forms

-Heterotrophic (cant make own food) & mostly saprophytic

-mycoses (illness caused by fungi)

-chitin cell walls + ergosterol in membrane

Characteristics of molds (fungi)

-multicellular

-hyphae: filamentous structures; form together into mycelium and thallus (body)

2 kinds of hyphae

1. Septate hyphae- possess walls between cells

2. Coenocytic hyphae- no cell walls or membranes between cells

Characteristics of yeasts (fungi)

-unicellular

-budding form: asexual reproduction (Formation of pseudohyphae when buds stick together)

-important for our food

Life cycles of fungi(chitin cell wall)

1.Sexual- cross or self fertilization

2.Asexual- mitosis, budding, fragmentation of hyphae

-Mold can have one or both modes of reproduction

Dimorphic fungi

can appear as either yeast or mold

Prominent phyla of fungi

1.Ascomycota

2.Basidiomycota

3.Microsporidia

4.Zygomycota

Fungi: Ascomycota

-fungi associated with food production, food spoilage, & human pathogens

-some have seperate hyphae & ascocarp fruiting bodies

ascospores

sexual spores

conidia

asexual spores

Aspergillus spp. (Ascomycota)

-mold, bread molds

-common cause of allergies and opportunistic infection of tissues

Candida albicans (Ascomycota)

-yeast

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

Penicillium spp. (Ascomycota)

-mold

-producer of antibiotics

Fungi: Basidiomycota

-Club shaped and produce basidiospores through budding

-Important decomposer and food source

-Includes puffballs, mushrooms, rusts, stinkhorns

-Many genera known as "magic mushrooms"

Amanita phalloides (Basidiomycota)

poisonous mushroom known as the death cap.

Fungi: 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

Fungi: Zygomycota

-Mostly saprophytic

-Coenocytic hyphae

-Zygospores used for sexual reproduction

-Sporangiospores for asexual reproduction

-Common to spoilage of strawberries

Mucor spp. (zygomycota)

necrotizing infections in humans

Algae

-autotrophic protists

-multicellular or unicellular

-ecologically and economically Important

-found in both Chromalveolata and Archaeplastida

Algae: Chromalveolata

-Dinoflagellates & stramenopiles

-Mostly marine

-Can be phototrophic, heterotrophic, or mixotrophic

Dinoflagellates (Chromalveolata: algae)

Traits:

-2 flagella (whirl)

-Theca (cellulose armor) -Some produce neurotoxins (red tide)

-Paralytic shellfish poisoning

Stramenopiles (Chromalveolata: algae)

-Golden algae (chrysophytes)

-Brown algae (phaeophytes) seaweed

-Diatoms (ochraphytes)

Major producers of O2 & silicon, Frustules, Diatomaceous earth

Red and green algae: Archaeplastida

Red algae - cell walls contain agar or carrageenan

Green algae - generally non-path; important in molecular bio research

Prototheca spp. (green algae)

exception to green algae, is pathogenic

-causative agent of protothecosis

-Found in sewage & soil

-Infection is rare, but possible

-Causes localized skin infections

Lichens

-Common soil and rock decomposers

-Non-pathogenic

-Many produce important antimicrobials for research

What is lichen?

Combo of green algae/cyanobacterium & ascomycete/basidiomycete fungus

symbiotic relationship of lichen

mutualism

where are lichen found?

-found in terrestrial places

-slow growing & can be centuries old

Lichens diversity

crustose(crust like appearance), foliose(leaf's), fruticose(rounded structure)

Lichen Anatomy

tylus=cortex, packed middle layer= medulla, photosynthetic partner=algal zone, rhizines= to attach to a substrate