Microbiology Chapter 5
Eukaryotes: Review the Compare/Contrast Prokaryotes and
Eukaryotes from Chapter 4
1. Cells are larger 50 – 100 microns (prok. 5 microns)
2. Membrane bound organelles
3. Appendages : Flagella; Cilia Different: made of protein
microtubules (9+2)
4. Cell wall is chemically simpler
5. Plasma membrane similar, some can use phagocytosis,
or pinocytosis
6. Cytosol aka. Cytoplasm fluid matrix, cytoskeleton of
protein tubes and fibers to anchor structures, provide
shape, and transport material within cell
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Eukaryotes: Organelles, membrane bound,
specialization of function.
Microbiology Chapter 5
Eukaryotes: Organelles, membrane bound, specialization of
function.
Nucleus: dbl memb. Contains almost all cell DNA;
chromosome. Nucleolus (nucleus within the nucleus)
Site of RNA synthesis and ribosome production.
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Eukaryotes: Organelles, membrane bound, specialization of function.
Endoplasmic Reticulum (ER) network of flattened mebranes
Rough ER studded with ribosomes, protein synthesis
Smooth ER – no ribosomes, lipid synthesis
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Eukaryotes: Organelles, membrane bound, specialization of function.
Golgi Complex: membranes and sacs where proteins are modified,
repackaged and shipped (like UPS or FED EX)
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Eukaryotes: Organelles, membrane bound, specialization of
function.
Lysosomes: Vesicles containing lytic enzymes (suicide sac)
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Vacuoles: membrane bound areas of storage; sugars, starch,
fat, even water. Especially in plants.
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Eukaryotes: Organelles, membrane bound, specialization of function.
Mitochondria: Cell power plant, most ATP made here. Site of Krebs cycle
and electron transport
Double membrane bound, inner membrane folded to increase surface
area (cristae). Imbedded are the cytochromes etc.
Inner fluid filled matrix contains enzymes for Krebs
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Eukaryotes: Organelles, membrane bound, specialization of
function.
Plant Chloroplast: site of photsynthesis, Carbon Dioxide and
water plus sunlight are made into glucose
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Eukaryotes: Organelles, membrane bound, specialization of
function.
Centromere (Centriole, Centosome) organelle made of microtubules,
generates spindle needed for Mitosis
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Eukaryotes: Survey of Eukaryote Microbes we study in this
class
Fungi
Protozoans
Helminths
Remember the overlap of
Arthropod vectors
Parasitology
Microbiology Chapter 5
Fungi: Mycology; Fungi make up there own Kingdom; a
very diverse group of organisms found in almost any
environment. They are prominent “decomposers” of dead
and decaying matter. Saprophyte is a term used to describe
their role in nature – live on dead material. They secrete
exoenzymes and absorb nutrients.
Morphology: Single celled – yeasts, used in baking and
brewing, some cause disease
Multicellular – Molds and mushrooms,
filamentous decomposers and some cause
animal and plant disease
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Yeasts:
1. Oval shaped
2.
3.
Reproduce asexually by budding
When growing on agar medium, appear pasty and form large
colonies. Special agar buffered to an acidic pH
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Molds : Filamentous (fuzzy) fungi. Cells are tube like and connected into
long filaments. The filaments are called hyphae or mycelium (hypha;
mycelia plural). They can branch off, form rhizoid root-like cells, aerial
mycelium with spore containing structures. Some filaments have cross
walls separating individual cells and others appear as a multinucleate
mass.
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Molds: Aerial mycelium of Penicillium, conidiophore (like arm,
fingers) conidiospores (asexual spores)
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Molds: Rhizopus, bread mold, aseptate, note “rhizoid”, stalk
(sporangiophore) and sporangium (black colored sac) filled with black
spores (sporangiospores – asexual)
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Molds: Some are “dimorphic” = two forms: grow in nature as
molds but in our bodies grow as yeasts. Some nasty
pathogens are dimorphic
Mushrooms and Bracket “shelf” fungi are common
decomposers in nature.
Microbiology Chapter 5
Basic characteristics of Fungi
1.
Saprophytes, heterotrophic, cell walls of chitin, a few are parasitic
(ringworms) and a few cause serious human disease.
2.
Distribution: ubiquitous (anywhere), any environment, temp. food
source, etc. They seem to prefer slightly cooler and more acidic
environments than bacteria. We use Sabouraud dextrose agar in
the lab.
3.
Economic importance: greatest negative impact is plant disease and
crop loss (Irish potato famine). Rusts, smuts, powdery mildew.
4.
Medical importance: Many human pathogens. We are pretty
resistant to fungal infections. Some are opportunists: Candida and
dermatophytes (ringworms). We will study 4 or 5 nasty respiratory
fungal infections later.
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Taxonomy of Fungi: A royal pain in the ______. Medical mycology
demands it. We must prevail. Know the 4 classes, based on
presence of a “sexual” spore. Know the examples given.
1.
Class – Zygomycetes; Forms a sexual spore called a “zygospore”,
asexual spores in a sporangium “sporangiospores”. Ex. Rhizopus
1.
Asexual
sexual
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2.
Ascomycetes: Sexual spores in an ascus (sac);
representative
organism is Penicillium; asexual conidiospores, sexual
ascospores
1.
Asexual – conidiospores
2. Sexual - ascospores
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3.
4.
Basidiomycetes: mushrooms, sexual spore at the end of a club like
“basidium”
Deuteromycetes; catch all class, no sexual mechanism noted.
Many human pathogens are found here. Candida would be a godd
example.
Candida – yeast
Candida pseudomycelium (weird)
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Protozoans: Kingdom Protista. Formerly thought of as
“animals” since they generally have no cell walls. Most are
free living in watery environments and have developed
special structure to expel excess water taken on in a fresh
water environmment. They also have a variety of
mechanisms for obtaining food.
Many exhibit two distinct “life” forms: A Trophozooite (troph);
an active feeding form. A Cyst, a non active “survival form”.
Many are parasites spread by the fecal-oral route. Most
acquire infections by ingesting the encysted form in
contaminated food or water.
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Classes of Protozoans – based on “Motility”
1. Flagellates (Mastigophora): Motile by flagella. Examples:
free living Euglena and parasites Giardia and Typanosoma
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Trypanosoma – sleeping sickness, transmitted via TSETSE
fly
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Sarcodinans – Amebas motile by pseudopods, many are
free living, some are parasites and cause disease
(usuallyfecal-oral )
Ameba proteus
Entameba histolytica
2.
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A quick word about life cycles of protozoans: troph - cyst
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3. Ciliates: motile by “cilia”. Free living Paramecium and
Intestinal pathogen – Balanditium coli (troph)
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Balanditium coli (cyst)
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4. Sporozoans (Apocomplexa) Not motile. Very complex life cycles
often with a vector. Plasmodium species causing malaria with a mosquito
vector. Toxoplasma parasite from cat litter box.
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Multicellular Parasites: Helminths; the worms. These
diseases are often diagnosed with microscopic examination
of stool samples for characteristic eggs.
Classified based on body form of adult worm (round or flat)
Platyhelminthes: Flat worms Nematodes: round worms
Platyhelminthes: Two divisions
Cestodes: tape worms; often long and segmented
Trematodes: “flukes” leaf like body forms
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Cestodes: tape worms; often long and segmented
Holdfast structure attached to intestine = Scolex
Segments: proglottids, as they mature produce fertile eggs
Either segments or eggs pass in the stool and contaminated
water or food
Taenia saginata – beef tapeworm
Taenia solium – pork tapeworm
Diplydium canium – dog tapeworm (complex life cycle)
Can be prevented, meat inspection, treat water, cook food,
good hygiene
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Taenia saginata – beef tapeworm
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Taenia solium – pork tapeworm; cook the sausage to 165
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Diplydium canium : don’t let fido lick your face
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Trematodes: “flukes” leaf like body forms, non segmented, complex life cycles,
many intermediate hosts (snails, fish), even free swimming larvae in contaminated
water Schistosoma mansoni
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Nematodes: round worms, very diverse group, from tiny, thread-like, to
giant pork roundworm (Ascaris)
Pinworms (a family affair) Enterobrius vermicularis (itchy butt, followed by
scotch tape test)
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Nematodes: round worms
Hookworm: Necator americanus, larva in warm moist soil, wear shoes
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Nematodes: round worms
Ascaris lumbricoides, giant pork roundworm (adults 12 inches long), can
block intestine, Ascaris types are common in pets (puppies need worming)
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Nematodes: round worms
Trichinella spiralis: cook pork, bear, and horse meat
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Nematodes: round worms; and so many more, filarial worms, heart
worms
filarial worms
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Anasakis worm in fish: Sushi? Anyone?
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Arthropod vectors: animals with “jointed” feet, bite
and transmit microbes
Fleas: plague, rabbit fever
Mosquito: malaria
Body louse : typhus
Flies: sleeping sickness
Kissing bug (Reduvids): American sleeping sickness
Ticks: arachnids; lyme disease, spotted fevers
See pg. 619 text
Microbiology Chapter 5