MBIO 1010 Chapter Notes - Chapter 16: Ignicoccus, Lithotroph, Nitrification
6 Dec 2016
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Breadth of phylogenetic diversity is similar to that of the bacteria and eukarya. Example: halobacterium salinarum: absolute requirement for high salt concentrations: Typically need at least 1. 5m (about 9%) nacl for growth. Found in : solar salt evaporation ponds, and salt lakes where the salt concentration approaches saturation. And soda lakes (highly alkaline hypersaline lakes. ) Adaptations for life in highly ionic environments: halophiles need to maintain osmotic balance. Usually achieved by accumulation or synthesis of compatible solutes. By increasing osmolarity inside the cell those compounds don"t interfere with other things: halobacterium salinarum pumps large amounts of k+ into the cell from the environment. Water flows into the cell, even in a hypersaline environment. Some haloarchaea have a unique system for generating energy: light-driven synthesis of atp without the use of chlorophylls. Absorbs light energy and pumps across the membrane to make a pmf. There are no autotrophs (carbon dioxide fixers) in archaea. Only microbes capable of significant methane production- methanogens.
