Lecture 1 Flashcards
Who invented The Microscope?
Early microscopes did not look like modern compound microscopes.
Zacharias Jansen, together with his father Hans invesnted the first “microscope” in 1595.
It had multiple lenses attaced to a sliding tibe (so it was a “compound” microscope) to magnify the specimen
It has a magnification of ~9X
Robert C. Hooke
In 1655, Robert C. Hooke invented a microscope that could magnify 50X.
It had different ways to magnify specimens, different ways to shine light.
Described “cells” for the first time from a sample of cork.
Antonie Von Leeuwenhook
In 1674, Antonie Von Leeuwenhook used better lenses, but only a single spherical lens (so not a compound microscope) and invented a microscope that could magnify 230X.
What happened between 1831-1833?
Robert C. Brown described the cell nucleus using orchid cells.
What are the 3 main points of the cell theory?
1) All living organisms are composed of one of more cells
2) The cell is the basic unit of structure and organization in organisms
3) Cells arise from pre-existing cells
*Matthias Schleiden and Theodor Schwann identified the first 2
Robert Remak
Worked as an assistant to Johannes Peter Muller (a physiologist), but did it for free.
He worked as a physician to fund his work. All of his work was self-funded.
He figured out a way to harden and stain cells (copper sulfate, vinegar, alcohol).
Found the cell membrane (discovered that cells come from other cells (cell division)… but he didn’t get the credit)
Rudolf Virchow
Stole the idea and presented it as his own.
He got credit for Cell Theory
Albert von Kolliker
In 1857, he “discovered” mitochondria (sort of).
He saw “granules” in muscle cells (happened to be mitochondria).
Richard Altmann
In 1886, he used dyes and called them “granules”… “bioblasts”
Carl Benda
In 1898, he coined the term mitochondria.
What is mitochondria derived from?
Derived from the Greek for the words thread (mitos), and granule (chondros).
Camillio Golgi
In 1898, he characterized the Golgi apparatus.
Golgi had to leave hia lab (financial problems).
Got a job as chief medical officer in a mental hospital.
Started a lab in his kitchen at home.
What did Camillio Golgi invent?
He invented the staining technique called the “Dark Reaction” that stained individual nerve cells (AKA The Black Reaction, The Golgi Stain, The Golgi Method)
Found a network in the cells that he called the “internal reticular apparatus”.
This was challenged by the field as the stain could just be a staining artifacts.
When electron microscopy was invented, the Golgi apparatus organelles was clearly visuaalized and named for Golgi.
Got Nobel prize (1906) NOT for discovering the Golgi apparatus but rather for the dark reaction.
How does the staining technique “Dark Reaction” work?
Fix the sample (with formaldehyde [as Golgi did] or paraformaldehyde or glutaraldehyde or a combination of them)
Put the sample in a solution of 2% potassium dichromate for 2 days
Dry the sample with filter paper
Put the sample in a solution of 2% silver nitrate for 2 days
Cut tissue sections
Dehydrate the sample using ethanol
Mount coverslip
Look on microscope
What you see is the microcrystalization of silver chromate in the neurons
What has been learned about this technique?
The technique has been honed since Golgi invented it. Using gold instead of silver to get finer structural details.
This ultimately led to the formation of the “Neuron Theory” (AKA Neuron Doctrine)
Golgi’s technique (the Dark Reaction) also let him see other things (eg. what we now know as the Golgi apparatus)
What is the Neuron Theory?
Neuron Theory was put forth by Heinrish Wilhelm Gottfried von Waldeyer-Hartz based largely from the work of the neuroanatomist Santiago Ramon y Cajal
What are some different ways to illuminate a sample?
Simple movement of the light source –> look down a device and physically move light around it to see different shadows
Move the light around to see different things
How to focus light onto the sample?
Move the components around to get different illuminations
Move the entire microscope
Reinhold Rudenberg
In 1931, he was part of the Siemens Company and he patented the electron microscope based on theories of using electrons as beams. He wanted to see the polio virus that infected his son.
Ernst Ruska and Max Knoll
In 1931, they invented and built the first electron microscope (as a PhD student).
In 1933, Ruska made a picture netter than a light microscope, using an electron microscope.
Siemens, with Ruska, produced the first commercial transmission electron microscope.
What magnification and resolution can light microscopes go until?
1000X magnification and resolution of 200nm
What magnification and resolution can light microscopes go until?
12,000X magnification and resolution of 50nm
Who got the Nobel Prize?
Ruska got the Nobel prize in 1986, and passed away in 1988.
George Otto Gey
He made the 1st cell line using Henrietta Lack’s cervical cancer cells (HeLa). They did this without her permission. Pubmed search for HeLa gives over 120,000 results.
How did we get the 1st cell line?
Henrietta Lacks was diagnosed with cervical cancer after going to John Hopkins hospital for a growth she found in her abdomen.
A surgeon at the hospital took a cervical tissue biopsy from Mrs. Lacks for diagnostic purposes.
At the time it was customary for the remainder of the tissue to be used and was delivered to Dr. Gey (without the consent of her + her family).
Gey was the head of the Tissue Culture Lab at the hospital and had limited success in generating an immortalized cell line.
He could grow cells in his lab, but after a few generation they would fail.
Another inventigator in the lab Mary Kibicek put them in a roller-tube and they grew very well.
How did we get the 1st cell line?
These cells are
1) cancerous
2) grew very fast and
3) grew generation after generation
Rudolph Jaenisch
Transgenic mice are produced by him (MIT).
He used a DNA virus to infect an early stage mouse embryo. The virus infected all of the cells of the embryo. The cells of the embryo contained the viral DNA and were thus “Transgenic”.
But, the genes were not passed onto successive generation, so it was not very useful.
The DNA did not get passed through the germ line.
What was the key to transgenic mice?
Transgenic mice (that are useful) are produced. The key was to get the germline mutated to pass on the altered gene to progeny.
Osamu Shimomura
identified aequorin from Aequorea victoria Jellyfish. When aequorin binds Ca2+ it makes GFP
Douglas C. Prasher
cloned the GFP gene and proposed that it could be used as a molecular tracer. He couldn’t get a grant to continue his work. Prasher gave his cDNA to many labs, but his cDNA did not give a green color because it had a tiny bit of the Jellyfish DNA still associated with it
Martin Chalfie
expressed GFP without the extra Jellyfish amino acids in E.coli and C.elegans (worm)
Fredrick Tsuji
Expressed GFP in E.coli, but was one month too late
Roger Tsien
Identifies mutant of GFP with enhanced spectral properties. He made different colors by mutating the original molecules.
Super Resolution Microscopy
Techniques to go beyond the theoretical optical resolution of a microscope of ~ 0.2um
Xuaiwei Zhuang
Stochastic Optical Reconstruction Microscopy (STORM)
Eric Betzig
Photo-activated localization microscopy (PALM), lattice light sheet microscopy, modification of structured illumination microscopy
