Several weeks ago, I put up a slideshow. I didn’t tell you what the pictures were because it’s fun to imagine what they could be or should be before being clued in. Today, I’ll reveal what each picture is and how the image was captured, but before we get into that, I’d like discuss a bit about “the small world.”
The human eye is capable of seeing large things. We can easily discern trees, houses, cars and people. On the smaller edge of life, we are able to resolve two blades of grass or two strands of hair. Unfortunately, there is a limit to our eyes. The “small world” is invisible to us if we only have eyes available to us as tools. For example, we cannot see the cells and proteins that are running our bodies. The limit of the human eye is ~ 100 µm (micrometers).
Luckily, to see smaller things, we have other tools available: light microscopes, electron microscopes, and crystallography (among other tools, such as atomic force microscopy). Table 28.1 breaks down the size of what each tool will allow us to see and provides examples of some real world objects that are indeed that size.
Tool
|
Smallest Size it can See
|
Examples
|
Human Eye
|
Down to 100 µm
|
Blades of grass, strands of hair
|
Light Microscope
|
Down to 0.1 – 1 µm
|
Cells
|
Electron Microscope
|
Down to 0.0005 µm
|
Large protein structures, viruses
|
Crystallography
|
Down to 1 Å (angstrom)
|
"single" proteins, atoms
|
Table 28.1 – Visualizing our “small world”
Light microscopy has come a long way from its humble beginnings. Currently, scientists are able to manipulate cells and open up color and contrast to this “small world” that our eyes can’t see. We are able to insert fluorescent proteins into cells and watch them move around; we are able to stain certain places in cells to clearly see the outline of plasma membranes, nuclei, endoplasmic reticulum or Golgi bodies. Thanks to Roger Tsien, Ph.D. of UCSD (University of California, San Diego), we are able to color these objects and all kinds of proteins with a whole rainbow of options. And, most importantly, we able to see things happen in side cells in both real time and at points along the way. Light microscopy is a powerful and valuable technique.
Nikon (of camera fame) offers a contest every year called the Nikon Small World – Photomicrography Competition. It is open to anyone over the age of 18 with an interest in photography of images taken through a light microscope. (read = you do not have to be a scientist to enter and it is an international contest). No limit exists on what the picture should be of, so you can see anything from cells to flowers to snowflakes in a highly magnified and colorful format. First place is $3,000 towards the purchase of Nikon equipment (they are tooting their own horn here) and the pictures go on a tour around the country. For the past several years, the exhibit had come to my place of work and I was able to see all the pictures. Some of them are truly gorgeous!
A few weeks ago, I went through the galleries of past exhibits (http://www.nikonsmallworld.com/gallery) and picked a few images that were visually interesting and/or showed a common object in a new way. And thus, my slideshow was born.
Photographer: Gloria Kwon, Memorial Sloan-Kettering Institute (New York, New York, USA)
What is it? A mouse embryo at 18.5 days. Mouse embryo is in red and the yolk sac is in green.
Magnification = 17 times
2005, Image of Distinction
Photographer: Viktor Sykora, Institute of Pathophysiology, Charles University (Prague, Czech Republic)
What is it? Drosera scorpiodes – a pygmy sundew (carnivorous plant!) Native to Southwest Australia
Magnification = 30 times
2005, 12th Place
Photographer: Edy Kieser (Ennenda, Switzerland)
What is it? Crystallized potassium chlorate. Think of it as looking at grains of salt very closely!
Magnification = 40 times
2010, 12th Place
Photographer: Dr. Gregory Rouse, Scripps Institution of Oceanography (La Jolla, California, USA)
What is it? A juvenile bivalve mollusk (like clams, oysters, mussels or scallops). This particular one is from the species Lima.
Magnification = 10 times
2010, Honorable Mention
Photographer: Dr. Alvaro Migotto, Centro de Biologia Marinha, Universidade de Sao Paulo (Sao Paulo, Brazil)
What is it? Enchinaster brasiliensis (a starfish!) embryo at four cell stage
Magnification = 60 times
Photographers: Julie Macklin and Dr. Graeme Laver, Australian National University, John Curtin School of Medical Research (Canberra, Australia)
What is it? Crystals of influenza virus protein neuramindase (see Influenza Series!)
Magnification = 14 times
If you are interested to see if the Small World Exhibit comes near you, check out this website: http://www.nikonsmallworld.com/tour
Want to see how a light microscope works? Here’s a wonderful website from one of my favorite podcasts/websites: http://science.howstuffworks.com/light-microscope.htm
I guess I need a new slideshow now! I’ll work on it. Stay tuned!
Micrometer: 1 micrometer = 1 x 10-6 meters or 0.000001 meters (super small!)
Light microscope: uses light and two lenses to magnify images
Electron microscope: uses electrons to illuminate objects instead of light
Crystallography: a technique that shoots X-rays at proteins to discern their structures
Atomic Force Microscopy: a technique that uses a very sensitive cantilever and tip to study surfaces. It can sense height differences of < 0.001 µm.
Å(Angstrom): 1 Angstrom = 1 x 10-10 meters or 0.0000000001 meters (über small)
REFERENCES
Roger Tsien’s Laboratory: http://www.tsienlab.ucsd.edu/
Nikon Small World official webpage: http://www.nikonsmallworld.com/
No comments:
Post a Comment