Micro bio Chapter 5- Eukaryotes

Giardia

• water borne protist

• causes severe diarrhea

Characteristics of protist

• animal like- protozoans- heterotrophs, unicellular

• plant like- algae- photosynthetic, either unicellular or multicellular

• fungi like- water molds

plankton

• microorganisms that drift or float in water

• zooplankton: motile and non photosynthetic

• phytoplankton: photosynthetic

trophozoites

• feeding stage of protozoans

cyst

cell with a protective wall

trophozoit becomes cyst (encystment)

Reproductive mechanisms- protozoans

• asexually: binary fission, budding schizogony

  • spores: sporosoites

  • Schizogony: nucleus of cell divides multiple times before cell divides into many cells→ products= merozoites

  • sexually: haploid gametes fuse through syngamy

Paramecium

• cilia for locomotion

• two nuclei- macro (polypoid) and micro (diploid)

• oral groove to ingest food

Amoeba

• pseudopodia anchor cell to surface and pull foward

Euglena

• whip like flagellum to propel

• not pathogenic

• two flagella, pellicle (shape), stigma (light sense), chloroplasts (photosynthetic)

Plasmalemma

• plasma membrane

ectoplasm

• outer gel layer, microfilaments of actin

endoplasm

• fluid region of cytoplasm

cytostome

• specialized feeding structure

cytoproct

• takes food in through endocytosis→ exocytosis of waste through cytoproct

Holozoic

• ingest whole food particles through phagocytosis

Saprozoic

• ingest small soluble food molecules

contractile vacuoles

• used to move water out of cell for osmotic regulation

modified mitochondria

• kinetoplastids or hydrogenosomes

Entamoeba

• E.histolytica- amoebic dysentery

• Naegleria fowleri

• brain eating amoeba, primary amoebic meningoencephalitis (PAM)

• enters through the nose→brain

• fatal

• warm fresh water places

Acanthamoeba

• keratitis (corneal inflammation and blindness)

Apicomplexans

• intra/extra cellular parasites

• apical complex- concentration of organelles, vacuoles and microtubules that allow parasites to enter host

• complex life cycles that include infective sporozoite undergoes schizogony to make merozoits

• Plasmodium- malaria→blood→liver→infects blood cells

Balantidum coli

• ciliate capable of parasitizing humans

Giardia lamblia

• diarrheal illness spread through cysts via feces

• flagilates

Trichomonas vaginalis

• flagellate

• sexually transmitted→ trichomoniasis

• no symptoms in men

• vaginal discomfort and discharge, pregnancy complication

Trypanosoma brucei

half cycle in fly, half in humans

• african sleeping sickness

• T. cruzi: chagas disease

Fungi

• unicellular or multicellular

• cell wall chitin

• cell membranes have dif. sterols call ergosterols

Mycoses

• illnesses caused by fungi

Septate hyphae

• walls in between

coenocytic (nonseptate) hyphae

• no walls

pseudohyphae

• reproduce via budding

Mycelium

• network of hyphae

Thallus

the body

Yeast

• unicellular fungi

• budding off→pseudohyphae

Candida albicans

• yeast forms pseudohyphae

• vaginal yest infections, oral thrush, candidiasis of skin

dimorphic fungi- candida albicans

• two forms, molds or yeast

• as mold: 25 C (77 F)

• yest cells: 37 C (98.6 F)

Fungi: sexual

haploid hyphae with gametes at the tips fuse forming two distinct nuclei (dikaryotic)

nuclei fuses: karyogamy→ forms diploid zygote

sygote undergoes meiosis to form spores → germinate to start the haploid stage

Fungi sexual spores

• zygospores

• ascospores

• basidiospores

Fungi asexual

• mitosis

• mitosis with budding

• fragmentation of hyphae

• asexual spores

  • sporangiospores

  • conidiospores

  • arthroconidia

Aspergillus flavus

• contaminant of nuts and stored grains

• produces aflatoxin: toxin and the more potent carcinogen

penicillium

• antibiotic

Coccidioides immitis

• valley fever

Candida albicans

• vaginal and yest infection

• normal microbiota of skin, intestine, genital tract and eat

Saccharomyces

• bakers yeast

• S. cerevisiae

Algae

• plant like protist

• unicellular or multicellular

• responsible for 70% of O and organic matter in aquatic environments

• Red algae: source of agar, agarose and carrageenan

• dinoflagellates

• diatoms

• golden, brown, red, green algae

Dinoflagellates

• when they become dense, red tide can occur-algal blooms

Chlamydomonas

• unicellular green algae

Lichen

• combination of two organisms symbiotic relationship

• epiphytes: grow on other plants

• can be seen as mutualism

• Upper cortex: provides protection

• Algal zone: photosynthesis occurs

• Medulla: fungal hyphae

• lower cortex: protection

• Rhizines: anchor the thallus to the substrate

types of lichen

• crustose lichen: crusty appearance, tightly attatched to the substrate

• foliose lichen: only be attatched at one point in the growth form and have second cortex below medulla

• Fruticose lichen: rounded structures and an overall branched appearance

Helminth parasites

• round worms: nematodes, intestinal parasites, often through undercooked foods

• flat worms: platyhelminths, transmitted through undercooked meat