Halobacterium mediterranei spec, nov., a New Carbohydrate-Utilizing Extreme Halophile.

ABSTRACT

The extremely halophilic rod-shaped bacterium, strain R-4, has features very different from other known Halobacterium species. As do all other extreme halophiles, the organism possesses a high excess of acidic over basic amino acids in its proteins, a cell wall lacking peptidoglycan, and ether-linked diphytanyl lipids. It differs from the "classic" halobacteria in several important ways it can use many different compounds as sole sources of carbon and energy. It is strongly amylolytic and lipolytic (against different Tweens), and does not produce H(2)S. The cell envelope of R-4 is much thicker than that of other halobacteria. The proportions of polar lipids in the envelope are different, and a new glycolipid sulfate is present in this strain. The envelope has a relatively low protein content, although a glycoprotein similar to the one of Halobacterium salinarium was detected. The G + C content (60%) is lower than that of other halobacteria. It is suggested that R-4 be designated a new species, Halobacterium mediterranei.