History of Microbiology Flashcards
started to understand what microbes are in last ______
how microbes work in last ______
- last 400 years
- last 150 years
when were microbes first discovered
required microscope
robert hooke- microscope but not very strong first drawings of microorganisms
anton van leeuwenhoek - refined the microscope (see prokaryotes)
why is culturing important ?
allows to do in vitro experiments / testings
axenic culture
- pure culture / only one species is present
theory of spontaneous generation
decaying matter, things that had started to rot, created microbes
support and denial of microbes being caused by decay
support:
- more common on decaying things
- sterile extracts are infected after being left for a while (spont gen even when sterile)
deny:
-requires life to form from non life / not observed in nature
- cover decay no flies (maggots) can get to it
- sealed items did not become infected with microbes
germ theory
decay is caused by microbes
support:
-sealed items no decay
-disproved for non microbial organisms
deny:
-vital force enough to form a microbe
-need oxygen for living things so spont. gen can’t occur without vital force
- too much heat kills organisms
final showdown of spontaneous generation
pouchet vs pasteur
-pouchet believed vital force (hay broth)
*spont gen DOES occur (was bacterial growth) ^endospores
-pasteur (beef broth) open to outside with swan neck flask ( no spont gen with these flasks ) *spont gen DOES NOT occur (correct)
what assumptions did both scientists make
- boiling killed all microbes (sterilized)
- oxygen required for life to develop (vital force)
why were their results so different
soil bacteria contains endospores which cannot be killed by boiling !
- hay broth likely contained soil bacteria
- the beef broth did not and so boiling WAS enough to fully sterilize
louis pasteurs work led to …….
aseptic technique and sterilization processes
-explained fermentation
robert koch
germ theory of disease
- tuberculosis
made a set of postulates to see whether a specific microbe caused a specific disease
4 postulates and *how might not conform
- microbe must be present in diseased individuals but not in healthy individuals
*can be carriers of disease without symptoms / some diseases are a combo of microbes - must be able to isolate the microbe from the host and grow it in a pure culture
**not all organisms can be grown in a pure culture - the same disease must result if a healthy organism is inoculated with the microbe
* - must be able to reisolate the same microbe that we injected
**
what mediates the immune system
interactions with antigens
variolation and * issue with it
= first step to develop vaccines
infect with a mild case to be protected from major strain
*couldn’t make sure was varioal minor to begin with
-risky /mercury / not sterile with no antibiotics
edward jenner
= vaccination much safer than variolation (inserting similar disease)
milkmaids didn’t get smallpox only cowpox on their hands
-weren’t getting smallpox / cowpox provided immunity
- testing on humans
why did these vaccines work
-cowpox structurally similar to smallpox and so antibodies against cowpox antigens would also recognize smallpox antigens
pasteur and cholera
can an old culture cause disease?
- attenuated (can’t cause disease) and has lost their pathogenicity
-old culture protected them from the fresh culture
*negative control (unvaccinated chickens)
alexander fleming
1928 discovers first antibiotic -penicillin
- zone of inhibition around the mold with no bacterial growth !
what are antibiotics aka two classes
bacteriocidal - chemicals that KILL growth of certain bacteria
bacteriostatic - chemicals that STOP growth of certain bacteria
antibiotics vs antibodies
biotics - chemicals to kill/inhibit bacteria
bodies - proteins produced by human immune system
microbial ecology
- winogradsky column = a way of culturing microbes that had specific biogeochemical functions (ex. converting between nitrogen to ammonia)
