LECTURE 2 Flashcards
what was francesco redi’s experiment to address the spontaneous generation theory?
and what was the conclusion of his experiment?
three flasks with meat inside:
unsealed=flies landed and laid eggs
flask sealed=no flies
flask covered with gauze=flies landed on gauze and laid eggs
flies only develop in meat that they can reach, disproved spontaneous generation
what did needham and spallanzani do?
needham sterilized broth but put it into a dirty flask and sealed it=microorganisms appeared
spallanzani sterilized the broth AND the flask= no microorganisms appeared
what did supporters of spontaneous generation think was necessary for it?
air
what was pasteur’s experiment?
boiled meath broth in a flask and curved the neck of the flask
air could enter but not dust (would settle in the curve)
no microorganisms developed
when he tilted broth into neck/broke neck then microorganisms developed
what were the conclusions of pasteur’s experiment?
microorganisms appear even when air enters
disproved spontaneous generation
microbiology became an experimental science as opposed to an observational science
what was tyndall’s experiment?
supported pasteur’s findings by showing that dust carries microorganisms
let dust settle in a closed box containing open tubes filled with broth
interior of box was coated with glycerin to trap dust particles
filled the open tubes with broth and boiled it
air could freely enter box but dust couldn’t enter and be resuspended
no microorganisms appeared after long periods of time
what did people believe diseases were caused by?
supernatural forces
poisonous vapours called miasmas
imbalances between the four humors of the body
1. blood
2. phlegm (mucus)
3. yellow bile (choler)
4. black bile (melancholy)
what did agostino bassi show?
that fungus can cause disease in silkworms, beginning of the germ theory of disease
what did berkeley show?
the great potato blight of ireland was also caused by a fungus
what did pasteur also show?
silkworms were parasitized by a protozoan in the french silk industry
started to raise healthy caterpillars
what did joseph lister do?
heat sterilised his instruments and used phenol on surgical dressings and wounds to prevent infection
influenced by pasteur’s work
high successful
suggested the role of microorganisms in causing disease
who are the fathers of microbiology?
robert koch and louis pasteur
what did robert koch demonstrate?
that a bacteria was causing anthrax
injected healthy mice with material from diseased mice (they became ill)
transferred anthrax to a series of 20 mice and they all got sick
show that disease can be transferred
incubated piece of spleen from mice 20 in beef broth and bacteria grew and produced endospores
isolated endospores-> put it into healthy mice -> developed anthrax
what are koch’s postulates?
relationship between microorganism and specific disease
1. the microorganism must be present in every case of the disease but absent from healthy organisms
2. the suspected microorganism must be isolated and grown in a pure culture
3. the same disease must result when the isolated microorganism is inoculated into a healthy host
4. the same microorganism must be isolated again from the sick host
how did techniques to study pathogens develop?
difficult to work with liquids
grow bacteria on solid surface and each colony would originate from one bacteria (clonal cultures, pure)
tried on slices of boiled potatoes, poor growth
tried on gelatin but that was degraded by microorganisms and gelatin melts at 37°C which is optimal growth for pathogens
agar was used, the petri dish was developed, media similar to body fluids were developed
pathogens were able to be isolated
