The Microbe World

What are Microbes?             |              Where Do They Live?

Microbes are everywhere - a largely unseen world of living things that support life processes. "The Microbe World" provides a comprehensive directory of micro-organisms and their activities.
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Shapes of Microbes

Microbes live in the water we drink, the food we eat, and the air we breathe. Right now, billions of microbes are swimming in our digestive systems and crawling on our skin! But don't worry, over 95% of microbes are harmless. Microbes are single-cell organisms invisible to the eye that come in different shapes seen only with microscopes.

There are thousands of species of bacteria, but all of them are basically one of three different shapes. Some are rod- or stick-shaped and called bacilli. Examples of rod-shaped bacteria include E.coli, Salmonella, and Bacillus anthracis which is the bacterium that causes anthrax in cattle. Rod-shaped bacteria include bent or curved rods; so Vibrio is a curved bacillus that causes cholera. Others are shaped like little balls and called cocci. Examples of bacteria with round cells include Staphylococcus, Streptococcus, and Neisseria (causes gonorrhea). Others still are twisted, helical or spiral in shape and called spirilla. These twisted cells can be flexible (Treponema which causes syphilis) or rigid corkscrew shape like Campylobacter (bacterium that causes food-borne illness). Some species of bacteria vary in shape; this is called pleomorphism. Variations and/or lack of rigid cell walls cause microbes like Mycoplasma, Corynebacterium, and Rhizobium to appear swollen, curved, or club-shaped.

Algae come in all sorts of shapes—some are round and others are oval. Some look like leaves and others like fat commas.

Protozoa generally have three different groups of shape. One group is the ciliates, which have hair-like projections called cilia on their flat tapered bodies. The second group is the amoebae, which can be subdivided into the testate amoebae, which have a shell-like covering on their blob-like body, and the naked amoebae, which don't have this covering. The third group is the flagellates, which have one or several long, whip-like projections called flagella poking out of their cells.

Viruses that come in a variety of shapes. Many are polyhedral or multi-sided. If you've ever looked closely at a cut gem, like the diamond in an engagement ring, you've seen an example of a polyhedral shape. Unlike the diamond in a ring, however, a virus does not taper to a point, but is shaped similarly all around. Other viruses are shaped like spiky ovals or bricks with rounded corners, balls with spikes sticking out on all sides, loaves of bread, tadpoles, or metal screws with spider legs.


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