History of Microbiology Flashcards
How are microbes essential for life on earth?
- literally grow everywhere
- first organisms to appear on the planet, evolution includes the evolving of planet earth
- vast realm of diversity in oceans
- human body contrains about same amount of microbial cells as human cells
how many microbial cells are there compared to human cells in us
what was the first life form on earth
marine bacteria
where can microbes exist
- pretty much any env on earth: hot springs, desserts, antarctic glacier, deep sub surface, salt crystal
- Every mol in nature can be used as a source of carbon or energy by a microorganism osmewhere on this plant
Prokaryotes were the first lifeform on earth, billions of years before the first eukaryote evolved (not surprising that they adapted to all of earth’s environments)
Eukaryotes, by comparison, occupy a very limited range of environments.
what is a Microbe
- living organism requiring a microscope to be seen
- most consist of a single cell but some are multi
- range from 0.2 micro meters to a few mm
- viruses acn be 10x smaller then the smallest cells
*each microbe contains in its genome the capacity to reproduce its own kind
- Genomes have been sequenced, can know total genetic info of organism (tells how many genes there are and can infer the coding capacity of that organism
- First sequencing fast enough to seq large genomes developed by fred sanger
- Todays sequencing generate metagenomes (all the genomes present in a given sample
Can get a large number of sequences to identify organisms present in sample
*Gives the diversity of organisms present
Does not tell us what it looks like, metabolism and how they interact (still need to culture)
**Today’s sequencing efforts generate metagenomes, collections of sequences from diverse populations of microbes taken directly from the environment.
what was the first genome to be sequenced
- Haemophilus influenzae
Closed single circular chromosome
Small genome 1.83 Mb encoding 1,749 genes
Obligate pathogen
Small geneome capacity, cant really do independent living
just a note: we study microbes have profoundly affected human demographics migrations, course of wars and cultural practices and economies
how have microbes hsaped human history
- effects of microbes were knwon in antiquity before microbes were recognized or known due to effects on:
- food security, food production (cheese, beer) and preservation, effects on infrastructure a (corrosion on concrete and metals), and human/animal and plant diseases
who is Robert Hooke
- built first compound lens microscope (30x magnification)
- frist to see and recrod eukaryote microbes
- observed and drew mold sporangia, mites, nemotodes
- coined the term cell
who is antonie van leeuwenhoek
Son of a cloth draper, experimented with grinding ever-stronger magnifying lenses
500x magnification
Very curious looking at lots of different things and drew them
Called the ‘wiggly things’ he saw animalcules
Discovered they were everywhere
first discoveries of immunology
Vaccine immunization is single most important development in prevention of disease
- Development of immunization: Observed that many people didn’t have the scars from small pox
in middle east they let posules dry, take scab off, grind it and then cut skina nd put on the powder
This would immitate the infection and hopefully introduce small enough dose to cause infection and not kill (hit and miss)
Edward jenner imporved by discovering that people in contact with animals had small chance of getting smallpox
Animals got a form of disease similar to humns, took the scabs on cows and test on young boy (boy became immune)
how was spontanous generation disproved
- poeple assumed If cant observe an organism grow and cant see it assumed it was spontaneous
Ex: if you leave meat exposed to env, you will eventually see maggots (assumed spon arrival)
- Discovered that the maggots were actually the off spring of flies
(if you sterilize the meat broth and put a cork It would not give rise to maggots (meat was not the source)
who is louis Pasteur
Chemist, microbiologist, industraial micrbiologist, immunologist\
Studied chirality of molecules
Discovered fermentation (developed yeast strains for beer industry
As a bacteriologist and immunologist, developed cure of rabies
Developed vaccines for cholera, anthrax and rabies based on weaked/attenuated vaccine strains
how was it discovered that microbes are in ambiet air/surroundings?
Exp of lewy pasteur that killed theroy of spon developemnt
Take flask and put in medica, make the swan neck, leave it open to air let stand and did not
If you tip the liquid into curve where the dust has settled then tip it upright it becomes cloudy, shows that microbes are present in material from the air
When started looking at cause of disease, took a sample from a person with TB and infecting that in diff animals to see if you could reproduce it in animals
1st, if you compare same sample from healthy and disease animal the diseased one will contain some organism not present in the healthy
*microbe present in all diseased animals
Look at what is present in diseased animal, inject it into the healthy and make sure it gives the same characterisitc of the sik
There has to be an animal host in which you can reproduce the disease ( some only cause diseases in a specific host
Not everything can be cultured (not bac and viruses not in this approach
what is microbial ecology
- russion scietist amoung the first to study microbes natural habitats
- discoviered lithotrophs
- developed enrichment cultures
- built the winogradsky column a model of a wetland ecosystem containing regions of enrichment for microbs utilizing diverse metabolism
- shows importance of global geochemical cycling of elements
- the column has a gradient of oxygen and carbon sources
