PERSPECTIVE ................................................................ 222 A Fruitless Search and Its Consequences ................................................................ 222 Three Ideas That Shape Our Concept of Bacterial Evolution .......................................................224 Procaryote-eucaryote dichotomy ..............................................................

The capacity of halophiles to thrive in extreme hypersaline habitats derives partly from the tight regulation of ion homeostasis, the salt-dependent adjustment of plasma membrane fluidity, and the increased capability to manage oxidative stress. Halophilic bacteria, and archaea have been intensively studied, and substantial research has been conducted on halophilic fungi, and the green alga Dun...

Adding acid to brines or mixing acid phosphate with the salt used in preserving fish was recommended by Gibbons (Progr. Rep. Atlantic Fish. Exp. Sta., no. 14, p. 13, 1935), because it was observed that under acid conditions the halophilic bacteria that spoil salted fish cannot grow. The red halophile, Halobacterium cutirubrum, was found to be extremely sensitive to pH changes (Kushner and Bayle...

Lately, there has been a special interest in understanding the role of halophilic and halotolerant organisms for their ability to degrade hydrocarbons. The focus of this study was to investigate the genes and enzymes involved in the initial steps of the benzene degradation pathway in halophiles. The extremely halophilic bacteria Arhodomonas sp. strain Seminole and Arhodomonas sp. strain Rozel, ...

1. Halobacterium cutirubrum L-alanine dehydrogenase was purified approx. 100-fold. 2. It has a mol. wt. of 72 500, about one-third that of two well-studied alanine dehydrogenases from non-halophiles. 3. The activity of the enzyme increases with temperature up to 70 degrees C, but the protein itself is not thermostable. 4. In the reductive amination reaction, the enzyme is fully active in the pr...

Haloarchaea are found at very high concentrations in salt-conditioned environments, hence produce enzymes which are able to catalyze reactions under harsh conditions, typical of many industrial processes. In the present study, culture conditions for extracellular amylase production from Haloarchaea isolated from a solar saltern were optimized and the purified enzyme was characterized. Haloferax...