Natronobacterium vacuolata sp. nov., a Haloalkaliphilic Archaeon Isolated from Lake Magadi, Kenya

Abstract

A novel haloalkaliphilic archaeon was isolated from Lake Magadi, a Kenyan alkaline soda lake. Cells of the organism contain large gas vacuoles in the stationary phase of growth, and colonies produced by these archaea are bright pink in appearance. The major polar lipids of these organisms are C2,C2, and C20C2s derivatives of phosphatidylglycerol phosphate and phosphatidylglycerol, and the organisms contain an unidentified phospholipid as a minor component. The G+C content of the DNA is 62.7 mol%. The name Natronobucterium vacuofutu sp. nov. is proposed. The type strain is designated NCIMB 13189.The haloalkaliphilic members of the Archaea (15) make up a distinct physiological group within the halobacterial (archaeal halophile) lineage (5, 9) in that they are confined to soda lakes and are obligately alkaliphilic. These archaea have been isolated from Lake Magadi, Kenya (13); Wadi Natrun, Egypt (12); Owens Lake, California (7); and Chinese and Russian soda lakes (16,17). Like other halobacteria, these organisms may produce a red coloration in brines (in this case, alkaline brines) due to the synthesis of C,, carotenoids. Lake Magadi is an exam le of a red soda m1-l.The haloalkaliphiles comprise rod-shaped and coccoid isolates that are classified into the genera Natronobacterium and Natronococcus, respectively. Representatives of the genus Natronobacterium are readily distinguishable from other rod-shaped halobacteria by virtue of their alkaliphily and low Mg2+ requirement (3). Natronococci have coccoid morphologies like Halococcus s p. but are distinguished from them by alkaliphily, low Mg' requirement, and partial lysis of cells in distilled water (4).Three species of natronobacteria are currently recognized:Natronobacterium pharaonis, N. magadii, and N. gregoryi (14). They are identified on morphological and biochemical grounds and by DNA-DNA homology studies. In addition, slight differences in polar lipid composition have been shown to distinguish these species (7).Here we report the isolation of a new rod-shaped haloalkaliphilic archaeon from Lake Magadi and its assignment as a new species of the genus Natronobacterium. lake, parts of which harbor lo7 to 10 P haloalkaliphiles MATERIALS AND METHODSMedium and culture procedures. Strain M24 was isolated by spreading on agar media, on site, dilutions of red pigmented brine taken from the side of the main causeway across Lake Magadi. Dilution medium and agar medium were described by Tindall et al. (13). The plates were incubated in sealed plastic bags at 37°C for 7 to 10 days. M24 was selected as producing bright pink colonies, whereas the other pigmented colonies on this agar medium were shades * Corresponding author. 401of red or orange typical for natronobacteria and natronococci.N. pharaonk DSM 2161, N. gregoryi NCMB 2189, and N. rnagadii NCMB 2190 were available for comparison. They were maintained and grown in the medium of Tindall et al.Light microscopy. Cells were Gram stained by the method of Dussault (2) and observed with a Leitz Orthoplan microscope. Uns...

Natrialba hulunbeirensis sp. nov. and Natrialba chahannaoensis sp. nov., novel haloalkaliphilic archaea from soda lakes in Inner Mongolia Autonomous Region, China.

“…Cell motility and shape were examined by phasecontrast microscopy without fixation and by Gram staining with acetic acid fixation. The optimal conditions of growth, reduction of nitrate and utilization of different carbon sources were determined as described previously Mwatha & Grant, 1993). Tests for catalase and oxidase activities and hydrolysis of starch, gelatin, casein and Tween 80 were performed as described previously (Gonzalez et al, 1978).…”

Halorubrum tebenquichense sp. nov., a novel halophilic archaeon isolated from the Atacama Saltern, Chile.

“…Halorubrum vacuolatum,the presence of S-DGD-3 is characteristic of the other members of this genus (Mwatha & Grant, 1993). Strain ALT6-92 T possessed a polar lipid pattern similar that to found in the genus Halorubrum (Trincone et al, 1990).…”

“…Haloarcula and Haloferax (Torreblanca et al, 1986), Halobaculum (Oren et al, 1995) and Natrialba (Kamekura & Dyall-Smith, 1995 Halorubrum tebenquichense sp. nov. et al (1986), Grant & Larsen (1990), Mwatha & Grant (1993), Kamekura & Dyall-Smith (1995) and McGenity & Grant (1995). j, Positive result ; k, negative result ; , not determined.…”

“…* Data obtained from Oren (1983), Grant & Larsen (1990), Mwatha & Grant (1993) and McGenity & Grant (1995).…”

Halorubrum arcis sp. nov., an extremely halophilic archaeon isolated from a saline lake on the Qinghai–Tibet Plateau, China

“…(McGenity & Grant, 1995;Kamekura & Dyall-Smith, 1995) are widely distributed in hypersaline habitats (Grant & Larsen, 2001). At the time of writing, there are 16 species with validly published names in the genus Halorubrum, including three alkaliphilic species, Halorubrum vacuolatum (Mwatha & Grant, 1993; Kamekura et al, 1997), Hrr. tibetense (Fan et al, 2004) and Hrr.…”