A LOOK AT ALGAE

Algae come in all flavors—colored blue, green, red, yellow, or brown—with or without a true nucleus, if you care to include cyanobacteria. Some of these members of the Protista and Monera kingdoms may be found in those tiny, nondescript puddles that form near air conditioner drains outside our homes. From the perpetually tumbling freshwater Volvox circling in the local pond, to the bioluminescent, seafaring dinoflagellates that bloom to form some of Florida's notorious red tides, algae are everywhere!

Observing them under a regular microscope is interesting, of course. Observing them with a fluorescence microscope such as, oh, say, the FluorEVER Microscope, is truly fascinating! When excited with a deep-blue LED, the chlorophyll in many species of algae will fluoresce in the deep red. Other cellular components may fluoresce at shorter or longer wavelengths, as well. A CCD camera to see (and record) images is vital when attempting to view at these longer wavelengths.

The following slide sheet presents side-by-side comparisons of images taken with a standard optical transmission microscope (Leitz Orthoplan), coupled to a color video camera, and my FluorEVER Microscope equipped with a b&w video camera. Though the chlorophyll present in each image actually fluoresces in the deep red, I pseudocolored the b&w images of the algae for effect. In most cases, there are very significant differences between the comparison images, as you can see.

NOTE: Lichens are a composite of fungi, algae, and/or cyanobacteria. The chlorophyll-containing organisms are referred to as photobionts. A small piece of a foliose lichen was removed from our palm tree and placed on a glass microslide with a drop of water and coverslip. No effort was made to section the piece. The left-hand photo taken through a 16X objective on the Leitz unit pretty well shows what the eye could see—namely, a field of green nothingness with several spore casings and some pollen. Using a blue LED on the FluorEVER Microscope revealed large, brightly fluorescent dots of algae in a matrix of fungi. Judging by the size of the dots and the overall color of the lichen, the photobionts appear to be green algae rather than cyanobacteria, such as Nostoc. The right-hand, tricolor photo is a composite made using three separate images. The images, in turn, were taken using red, green, and blue filters in tandem with a long-pass filter centered at 475 nm. I should mention that not much detail could be seen by eye, and a CCD camera was absolutely, positively needed to reveal the fluorescent image.

Euglena is a member of the protozoan order Euglenida and a member of the algal phylum, Euglenophyta. Neither plant nor animal, most members of this delightful genus photosynthesize their own food using built-in chloroplasts and sunlight. At night, or for those members who have lost their chloroplasts, a more traditional feeding method is required. When you view the video, you may notice a thin, whip-like flagellum located at the narrow end of the organism. Note, too, the eyespot or stigma lying near the base of its flagellum, which guides the Euglena to the light. A few quick views of several species of Euglena will be followed by sequences showing their fluorescence in the red.

FluorEVER's vertical illuminator was set up with a blue LED emitting light @ 450 nm. A long-pass filter permitted the chlorophyll's fluorescent wavelengths (those lying above 570 nm) to be recorded by a b&w camera.

One characteristic of many species of Euglena is the remarkable squirming motion, dubbed euglenoid movement, which is quite evident in the video. These Euglena were found in that tiny, nondescript puddle I referred to in the introduction, which has always proven to be a reliable source.

Volvox are the living embodiments of Ptolemy's cycles and epicycles. These organisms are so uniquely beautiful that both zoologists and botanists want to claim them for their own! Zoologists have placed Volvox in the order Volvocida, reserved for phytoflagellates. Botanists have categorized Volvox as a member of the Chlorophyta (green algae) division of the Protista kingdom.

A colony of bi-flagellated, chloroplast-containing, Chlamydomonas-like organisms, bound together by networked strands of cytoplasm, makes up this hollow ball of jelly. About the size of a small pinhead, less than a millimeter in diameter, the Volvox somehow coordinates the rowing action of between 500 and 50,000 separate cells to produce a directed motion that propels the Volvox through its world.

Daughter cells, forming the inner globes seen here, eventually break out to create new colonies. In this video, the red-fluorescing chloroplasts have been pseudocolored a greenish hue.