Written by Dr. T. M. Wassenaar Tuesday, 23 December 2008 16:36The 'exhibits' of our museum contain text only. This enables easy access for every visitor. Not everybody has the fastest of computers. And we refrain from copying other people's pictures. The most interesting features of bacteria are their lives, less their looks. But a picture can say more than a thousand words, so here are some links to images of bacteria.
There are different ways of looking at bacteria. Bacteria growing in a liquid will generally make the liquid cloudy, and sometimes change color, but by the look of such a broth it is hard to determine what type of bacteria are growing in it.
More typically, bacteria are plated out on dishes filled with a solidified medium. Agar (a polycarbohydrate similar to gelatin) is usually used to produce a solid medium plate, called a 'Petri dish' (who was Richard Julius Petri?). The colors of the plates vary with the media used, but the growth can have bright colors, too, or change the color of the plates. See why 'color lovers' admire bacteria. Bacteria are put on and care is taken to spread them out so thin that single cells cover the plate. Each of these cells will grow into a colony. How to produce single colony streaks. The morphology (shape, color, shine, etc.) of colonies is often characteristic of the bacterial family or species.
Look at colony morphology at the following sites:
A special form of bacterial growth is biofilms. These films are a continuous layer of growing organisms and often contain different species. Biofilms are complex structures, and understanding biofilms is a subject of a lot of research. More about Biofilms, presenting some Electronmicroscopic pictures.
A bacteriologist will not only observe colonies on agar plates, but probably also look at the bacteria down a microscope. The color and appearance are sometimes manipulated by chemical stains, for instance the Gram Stain, which will differentiate gram-positive bacteria (the ones that stain deep purple) from the gram-negative ones. The Gram stain explained.
Listed below are the best picture galleries of Bacteria available on the web:
A word of warning: please respect the copyright of the owner before downloading or using any of these pictures.
Last Updated on Monday, 07 November 2011 22:37