Life evolved to be lived with its cells bathed in and containing fluids of a specific saltiness (salinity). Yet some organisms have adapted to live in habitats as salty as the Dead Sea in Israel (28% salt), the Salt Lake in the US, the salt lake sediment in Tunisia, the microbial mats of Russia and many places elsewhere. How do they do it?

After all, when normal cells are dropped into salty water, they typically lose their water and die. Salts pull water from cells, and even from within the structures of proteins, so the proteins lose their shape. Since some polymers like sugars and proteins are found stuck onto the outside of cells, they are at particular risk unless the organism develops a good strategy for dealing with the salt.

How do halophiles do it? We know about several different strategies.

Halophiles interact more strongly with water using different means, including using more negatively charged amino acids in key structures.

Halophiles can make many small proteins inside the cell, and these, then, compete for the water.

Halophilic archaea, on the other hand, accumulate A LOT of salt in the cell in order to outweigh the salt outside.

 

By the way, DNA is transcribed diffently, depending of the concentration of salt.

See Life on the Edge by Michaal Gross 1998. Plenum Press