Lecture 2 Notes - Med Micro

according to the world health organization, there are 6 parasitic diseases that represent what?

the top 20 microbial causes of death

in a year, there are approximately 5 million cases of what infectious diseases?

malaria, amoebiasis, intestinal parasites, and fungal infections

infectious eukaryotic microbes include what three things?

fungi, protozoa, and helminths

why are infectious eukaryotic microbes difficult to treat?

because there are not as many targets for treatment

what are arthropods?

common mode of transmission; often difficult to control

what is cilia?

short and numerous hairlike extensions used for motility and also found on the surface of various human cells

what is the nucleus?

intracellular structure that houses cell’s DNA and serves as the cell’s command center

what is the nucleolus?

a dense region of nucleus enriched with RNA

what is rough ER?

an intracellular structure that has ribosomes on the surface and is mainly involved in protein production and detoxification

what is smooth ER?

an intracellular structure that lacks ribosomes on surface and is central to lipid production and detoxification

what is the golgi apparatus?

an intracellular structure that modifies cellular proteins, builds lipids, and further sorts + distributes finished products

what is the golgi apparatus central to?

secretion

what is the mitochondria?

an intracellular structure that generates most cell ATP

what does the mitochondria contain?

its own circular genome and 70S ribosomes

what are chloroplasts?

photosynthetic only; harvest energy from light

what do chloroplasts contain?

their own circular genome and 70S ribosomes

what are vesicles/vacuoles?

buds from membranous organelles and/or plasma membrane; they store and transport substances

what do vesicles/vacuoles transport?

lysosomes and peroxisomes

what are examples of those in the animalia kingdom?

birds, helminths, reptiles, mammals, fish, amphibians, sponges, and anthropods

what is the organization of the animalia kingdom?

multicellular

what is the reproduction of the animalia kingdom?

sexual and asexual

does the animalia kingdom have a cell wall?

no

what are medical examples of those in the animalia kingdom?

parasitic worms; many anthropods like ticks and mosquitos transmit infectious diseases

what are examples of the fungi kingdom?

yeast, molds, mushrooms

what is the organization of the fungi kingdom?

some uniceullar (yeasts), but most are multicellular (nonyeast fungi)

what is the reproduction of the fungi kingdom?

sexual and asexual

does the fungi kingdom have a cell wall?

yes

what are medical examples of the fungi kingdom?

Candida albicans cuases yeast infections; Pneumocystis jirovecii causes infections in the immunocompromised (esp. AIDS)

what are examples of the protista kingdom?

euglena, diatoms, amoebas, paramecia, algae, and slime molds

what is the organization of animal-like protists (protozoa)?

unicellular

what is the organization of plant-like protists?

unicellular or multicellular

what is the organization of fungus-like protists?

unicellular or multicellular

what is the reproduction of the protista kingdom?

sexual and asexual

does the protista kingdom have a cell wall?

some (examples: slime molds at certain life stages, and algae)

what are medical examples of the protista kingdom?

various Plasmodium species cause malaria; Entamoeba histolytica causes dysentery; certain algae make toxins (such as the ones that cause red tide blooms)

what are helminths?

worms

what are the two different phylums of helminths?

roundworms and flatworms

what is the subtypes of roundworms?

nematodes

what is the structure of roundworms?

non-segmented, elongated, cylindrical

what is the reproduction of roundworms?

sexual reproduction (two sexes)

what is an example of a roundworm in humans?

pinworm and Trichinella

what are transmission mechanisms?

fecal/oral (eat eggs in contaminated food, water, or soil) or eat undercooked meat

what is the subtype of flatworms?

tapeworms (aka cestodes)

what is the structure of tapeworms?

segmented, flat, ribbon-like

what is the reproduction of tapeworms?

sexual; hermaphroditic (male and female reproductive organs in same individual)

what is an example of tapeworms in humans?

Taenia saginata from beef

what is the transmission mechanisms of tapeworms?

fecal/oral through contaminated food or water; eating undercooked meat or fish from an infected animal

with helminths, there are various life stages that can be infective depending on what?

species

what is the parasitic species?

the species that can live in humans

what do some parasites do?

some absorb a host’s food, body fluids, and tissues

what kind of motility do parasites have?

little-to-no motility

what is the reproduction of helminths?

complex; male or female or hermaphroditic

most tapeworms are what?

hermaphroditic

do tapeworms have a digestive system?

no

what of the tapeworm anchors to the intestinal wall?

the scolex (head)

how do tapeworms absorb food?

through the cuticle (tough skin)

what are proglottids?

segments in tapeworms that break off to spread eggs

what is taania saginata?

beef tapeworm spread by ingesting undercooked beef, contaminated water, fecal matter; causes Taeniasis

where do roundworms live?

free-living in soil or parasitic lifecycles

reproduction life of roundworms

bisexual (larvae or egg may be infective)

do roundworms have a digestive system?

yes

where do pinworms spend their life?

entire life in human intestine

what is trichinella?

trichinosis; where cysts in undercooked meat are ingested and organisms reproduce in the GI tract

with trichinella, what do worms do?

they encyst in muscle tissue

what is the most common helminthic infection in the US?

pinworm

what is enterobius vermicularis known as?

pinworm

with pinworm, what first happens?

eggs are ingested person-to-person or by touching contaminated objects and then touching the mouth

what happens second with pinworm?

ingested eggs hatch in the small intestine; adult worms migrate to colon to mate

what happens third with pinworms?

female worms migrate to anus at night to lay eggs on the perianal skin, causing itching (leading to transmission to others)

what is another name for trichinosis?

Trichinella spiralis

how does one get trichinosis?

by eating undercooked pork containing cysts

what is mycology?

the study of fungi

what is mykes?

greek for mushroom

fungi can be what?

unicellular or multicellular

what do many fungi do for reproduction?

form spores or bud off for reproduction

how many known species of fungi are there?

75,000

less than how many fungi species cause disease and most accidental infections?

less than 100 species

what do fungi live on?

organic matter (by absorption)

do fungi have chlorophyll?

no (they are not plants)

what do fungi metabolize?

complex carbohydrates (most are saprobes/decomposers)

fungi are eukaryotes, and therefore….

there are fewer targets for antifungal treatments

what are yeasts?

unicellular fungi

what is fission?

dividing symmetrically (yeasts)

what is budding?

dividing asymmetrically (yeasts)

what type of fungi are molds?

filamentous fungi

how do molds appear?

as masses of intertwined, tubular filaments (may be unicellular or multicellular)

what are hyphae?

projections of filaments (form spores)

what is mycelium?

a mass of hyphae

what is fungal dimorphism?

when some pathogenic dimorphic fungi are moldlike under certain conditions and yeastlike under other conditions

when does fungal dimorphism occur?

in conditions of extreme temperature, pH, and nutrient availability

what is an example of fungal dimorphism?

Candida albicans (yeast infections)

what are fungal diseases called?

mycoses

are mycoses contagious?

not very

how is mycoses spread?

through inhalation of spores on air particles; direct contact

what is mycoses due to?

the growth of the fungi (mostly accidental infections)

what happened in 2012/13 pertaining to mycoses?

fungal meningitis came from steroid injections

are mycoses difficult to treat?

yes; they are locale, and there are few targets for antifungals

what do SOME fungi secrete?

mycotoxins

what does the fungal secretion of mycotoxins lead to?

inflammatory reactions, GI symptoms, kidney/liver damage, cancer, and others

what are mycotoxins?

toxins that are usually ingested or inhaled (from fungi)