No, I’m not talking about the birth of food production in the Fertile Crescent (can you tell I’ve been reading Guns, Germs, and Steel?), I’m talking about the first digital images of fluorescence taken on the BioBus. The generous donations of a camera from Edmund Optics along with a lens adapter from Olympus have enabled us to start making still pictures, time-lapse sequences, and video-rate movies of cells. Below is one of the first composite images I took with the camera. Composite means that the picture is actually two images added together: the blue shows where DNA is and the green shows filaments of actin protein. These filaments form a spider’s web-like network in the cell’s cytoplasm that allow the cell to do things like move and eat. Each blob of blue is the DNA of a different cell. Do you count 6 separate blobs?
Green actin with blue DNA
The microscope slide I used to make this picture was donated to the BioBus by Tomas Perez at Columbia University. Tomas uses fluorescently labeled cells in his research to let him track the whereabouts of certain proteins inside the cell. For instance, in the above image you see that the blue stained DNA is located at the center of the green-stained cytoplasmic network of actin. Do you know why DNA stays in the center of the cell and doesn’t spread out into the cytoplasm? Hint: it starts with the letter ‘N’.
These cells came from petri dishes that Tomas keeps full of so called ‘immortalized’ mouse cells. Immortalized means that these cells can grow forever on a petri dish, without ever needing to be in a mouse again! Tomas then chemically ‘froze’ or fixed the cells in place, after which he stained the cell with special chemicals designed to recognize only certain cell structures (in this case the structures of DNA and actin filaments) and make them glow. This is like putting fluorescent colored clothes on certain parts of the cell and then shining a black light on it, like you might do at a party! And believe me, cells CAN dance.
Our ability to take digital fluorescent images is also exciting since we are working on a grant to fund building a large library of fixed and stained samples for the BioBus in order to see all the different organelles and structures (like mitochondria and ribosomes). We can also look for differences between cells from different places. Perhaps student-researchers aboard the BioBus will discover a difference between cancer and non-cancerous cells? It’s not impossible.
If you are a scientist and you have fluorescently-labeled samples you would like to donate to the BioBus, please contact me (ben@biobus.org). We currently have filter cubes for UV, GFP, and Rhodamine excitable dyes.