organelles such as the chloroplast, so sequestration of salt is seen. Under this action, salt is stored within the vacuole to protect such delicate areas. If high salt concentrations are seen within the vacuole, a high concentration gradient will be established between the vacuole and the cytoplasm, leading to high levels of energy investment to maintain this state. Therefore, the accumulation of compatible cytoplasmic osmotic solutes can be seen to prevent this situation from occurring. Amino acids such as proline accumulate in halophytic Brassica species, quaternary ammonium bases such as Glycine Betaine and sugars have been shown to act in this role within halophytic members of Chenopodiaceae and members of Asteraceae show the buildup of cyclites and soluble sugars. The buildup of these compounds allow for the balancing of the osmotic effect while preventing the establishment of toxic concentrations of salt or requiring the maintenance of high concentration gradients. Bacterial halotolerance The extent of halotolerance varies widely amongst different species of bacteria. A number of cyanobacteria are halotolerant; an example location of occurrence for such cyanobacteria is in the Makgadikgadi Pans, a large hypersaline lake in Botswana. Fungal halotolerance Fungi from habitats with high concentration of salt are mostly halotolerant (i.e. they do not require salt for growth) and not halophilic. Halophilic fungi are a rare exception. Halotolerant fungi constitute a relatively large and constant part of hypersaline environment communities, such as those in the solar salterns. Well studied examples include the yeast Debaryomyces hansenii and black yeasts Aureobasidium pullulans and Hortaea werneckii. The latter can grow in media without salt, as well as in almost saturated NaCl solutions. To emphasize this unusually wide adaptability, some authors describe H. werneckii as "extremely halotolerant". See also References Environmental microbiology Geomicrobiology Microbial growth and nutrition de:Halophil