Culturing Viral Host Organisms:

Created by George Rice, Montana State University

Aerobic Culturing:

Samples that are taken aerobically are inoculated into a variety of culture medias in the lab. When culturing aerobic thermophiles, such as Sulfolobus, small amounts of the environmental sample are inoculated into media contained in the long necked flasks shown above. The flasks are then placed in liquid baths that are kept at a constant 80 degrees centigrade. Long necked flasks prevent the media from evaporating at the required elevated temperature. All samples are then monitored for the growth of thermophiles by checking for changes in optical density, color, and smell.

Anaerobic Culturing:

Anaerobic organisms are grown by inoculating sealed tubes or vials (shown above left) that are prepared by filling partially with growth media, and then replacing the head space gas with either hydrogen, nitrogen, carbon dioxide, or some combination thereof. The type of media and headspace gas that are used are tailored to the types of organisms that are being cultured (learn about viral hosts in Yellowstone). An alternate method entails plating environmental samples in an anaerobic hood onto plates that are prepared with a modified solid media designed to withstand elevated temperatures and varied pHs. These plates are then placed in an anaerobic jar (shown above right) which is designed for easy replacement of the ambient atmosphere with the appropriate gasses. The anaerobic vials or jars can then be placed in ovens to incubate at a desired elevated temperature.