Some of the most commonly occurring but difficult to isolate halophilic prokaryotes, Archaea as well as Bacteria, require or prefer pyruvate as carbon and energy source. The most efficient media for the enumeration and isolation of heterotrophic prokaryotes from natural environments, from freshwater to hypersaline, including the widely used R2A agar medium, contain pyruvate as a key ingredient....

Halophilism has been of considerable interest since the report of Farlow (1880) on the reddening of salted fish. Any industry using either a salt packing process or a salt brine must be concerned with the control of halophiles. Considerable work has been done, therefore, with the isolation, identification, and control of these organisms. Stuart, Frey, and James (1933), Gibbons (1936), Lefevre a...

Glycine betaine is a compatible solute, which is able to restore and maintain osmotic balance of living cells. It is synthesized and accumulated in response to abiotic stress. Betaine acts also as a methyl group donor and has a number of important applications including its use as a feed additive. The known biosynthetic pathways of betaine are universal and very well characterized. A number of ...

Antisera were raised in rabbits against ribosomal proteins of Methanobacterium bryantii and used to analyze immunological relationships to ribosomes from other archaebacteria, from eubacteria, and from yeasts. Cross-reaction could be detected within the methanogens and with a member of the extreme halophiles; the degree of immunological similarity reflected the relationship delineated by 16S ri...

Bacteria classified as extreme halophiles, in the genera Halobacterium and Halococcus, contain deoxyribonucleic acid (DNA) which displays two components in a CsCl equilibrium density gradient. The base composition of the major DNA component ranges from 66 to 68% guanine plus cytosine (GC), whereas that of the satellite DNA comprising some 11 to 36% of the total, is between 57 and 60% GC. Purifi...

Information is meager concering the influence of salts on the metabolic processe of halophiles. In fact, reports of the work of Robinson et al. (1952) are the only recent studies in this field. Robinson (1952) showed that there was an optimum concentration of sodium chloride for maximum activity of lactic acid dehydrogenase. While studying the effect of salt on Micrococcwu halodenifns, Robinson...

This section provides an overview of the genetic systems developed in the Archaea. Genetic manipulation is possible in many members of the halophiles, methanogens, Sulfolobus, and Thermococcales. We describe the selection/counterselection principles utilized in each of these groups, which consist of antibiotics and their resistance markers, and auxotrophic host strains and complementary markers...