Yeasts

The Good:

Yeasts are microscopic, single-celled fungi. Unlike bacteria, which can thrive on many different types of food, most yeasts can live only on sugars and starches. From these, they produce carbon dioxide gas and alcohol. Thus, they have been useful to man for centuries in the production of foods and beverages such as bread, wine, and beer. Because they can grow under conditions of high salt or sugar content, they can cause the spoilage of certain foods in which bacteria would not grow. Some yeasts are psychrophilic (able to grow at relatively low temperatures), and can create spoilage problems in refrigerated storage areas.

Unlike bacteria, which multiply by binary fission, most yeasts reproduce by a method called budding. A small knob or bud forms on the parent cell, grows and finally separates to become a new yeast dell. Although this is the most common method of reproduction, yeasts also multiply by the formation of spores, and a few yeasts undergo binary fission.

The Bad & The Ugly:

Certain yeasts are pathogenic, e.g. Candida albicans:

Overall however, yeast infections are much less common than are bacterial infections.

MicrobiologyBytes Video Library by MicrobiologyBytes is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://www.microbiologybytes.com/blog/about/