Halotolerance

Fields of scientific research relevant to halotolerance include biochemistry, molecular biology, cell biology, physiology, ecology, and genetics. Studying the mechanisms of halotolerance in microorganisms can be applied to organism growth and ecosystem dynamics in increasingly saline environments. Halotolerance can be applied to pollution and climate change; processes of halotolerance may be implemented to limit the damages of pollution. Halotolerant microorganisms may be utilized as bioremidators in contaminated soils and in waste water. Fermentation processes in food that use salt can utilize halotolerant organisms. Lactobacillus pantarum is used in the production of pickles and sauerkraut, and other halotolerant bacteria are used in the production fish sauce and soy sauces. Environment stressors like drought and extreme temperatures can involve or induce osmotic changes, so applying knowledge of halotolerance is relevant to environments with extremes in moisture or temperature. Bioactive metabolites of halotolerant organisms may limit the growth of cancer, especially lung and breast cancer, and may have applications in chemotherapy resistance and treatment-related toxicity. ==Cellular functions of halotolerant organisms==

Tolerance of high salt conditions occurs through several physiological mechanisms. High concentrations of salt in soil or water that plants live in can trigger ionic imbalances which cause complications in respiration and photosynthesis, leading to reduced rates of growth, injury and death in severe cases. To be considered tolerant of saline conditions, the protoplast must show methods of balancing the toxic and osmotic effects of the increased salt concentrations. Halotolerant organisms must cope with the stress of changing and high salinity; osmotic stress and ionic stress is put on cells in high salinity. An environment of high salinity leads to loss of water in the cell, so halotolerant organisms have developed mechanisms to retain water and sequester salt within the cell. In some organisms, flagellum-related genes are down-regulated in environments with high concentrations of salt which conserves energy of motion to be used in osmoprotection. ==Bacterial halotolerance==

The extent of halotolerance varies widely amongst different species of bacteria. A number of cyanobacteria are halotolerant, such as the cyanobacteria of Makgadikgadi Pans, a large hypersaline lake in Botswana. Cyanobacteria possess a high level of physiological flexibility; recent research on the mechanisms of halotolerance in cyanobacteria using omics approaches aim to identify the gene networks and biochemical pathways of halotolerance like those that produce osmoprotectants. == Fungal halotolerance ==

Before the 2000s, it was commonly believed that fungi did not inhabit extremely saline environments, but research has disproved the idea by finding fungi in solar salterns. Fungi from habitats with high concentration of salt are mostly halotolerant, few are halophilic. Well studied examples include the yeast Debaryomyces hansenii and black yeasts Aureobasidium pullulans and Hortaea werneckiiwhich can grow in hyper saline conditions, making them model organisms to study halotolerance. Mechanisms of halotolerance in fungi include regulating intracellular ion concentrations and accumulating osmoprotectants to maintain osmotic balance without toxicity or disrupting cellular metabolic activity. == See also ==