Halobacterium sp. GRB: a species to work with!?

The properties of the halobacterial isolate Halobacterium sp. GRB are discussed, especially in relation to its use as a laboratory strain. Experimental results on this species are described, including the isolation of point mutants in the bacterioopsin gene leading to single amino acid replacements in bacteriorhodopsin, the application of a selection procedure for the isolation of different types of mutants, the genetic stability of Halobacterium sp. GRB and the possibility of isolating a set of isogenic mutants, the conditions for transformation experiments with this species, and specific features of Halobacterium sp. GRB, such as halocin production and the absence of a restriction system, as well as DNA adenosine methylation.