|
|
||||||||
1 School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
2 Australian Center for Astrobiology, Macquarie University, Building E8C 153, Sydney, NSW 2109, Australia
3 Department of Applied Chemistry, Faculty of Engineering, and Bio-Nano Electronics Research Center, Toyo University, 2100 Kujirai, Kawagoe, Saitama 350-8585, Japan
4 Halophiles Research Institute, 677-1 Shimizu, Noda, Chiba 278-0043, Japan
Correspondence
Brett A. Neilan
b.neilan{at}unsw.edu.au
Extremely halophilic archaea were cultivated from smooth and pustular microbial mats collected from Hamelin Pool, Shark Bay, Western Australia. On the basis of morphology, two phenotypes were present and 16S rRNA gene sequence analysis indicated that all strains were most closely related to members of the genus Haloferax (98.1–99.4 % similarity). One representative strain from each phenotype was selected for further taxonomic characterization. Strain SA5T, isolated from the smooth mat, formed small (
1 mm diameter), red, translucent colonies on agar medium and strain PA12T, isolated from the pustular mat, formed large (3–5 mm diameter), pink, mucoid, domed colonies. Both strains grew in media with 1.7–5.1 M NaCl, required at least 0.2 M Mg2+ for growth and had pH optima of 7.4. The 16S rRNA gene similarity between strains SA5T and PA12T was 97.1 %. Physiological properties, G+C content and polar lipid composition supported placement of both strains in the genus Haloferax. Phenotypic analysis indicated that the two strains were distinct from each other and from all other members of the genus. This was confirmed by the low DNA–DNA relatedness between strains SA5T and PA12T (18–30 %) and between both strains and all other recognized Haloferax species. Two novel species of the genus Haloferax are proposed to accommodate these novel isolates, Haloferax elongans sp. nov. (type strain SA5T=JCM 14791T=ATCC BAA-1513T=UNSW 104100T) and Haloferax mucosum sp. nov. (type strain PA12T=JCM 14792T=ATCC BAA-1512T=UNSW 104200T).
The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of Haloferax elongans sp. nov. SA5T and Haloferax mucosum sp. nov. PA12T are DQ860977 and DQ860980, respectively.
Phase-contrast micrographs of late-exponential-phase cells of SA5T and PA12T (Fig. S1), SDS-PAGE patterns of whole-cell proteins (Fig. S2) and TLC analysis of polar lipids (Fig. S3) of SA5T and PA12T and reference taxa are available with the online version of this paper.
This article has been cited by other articles:
![]() |
A. Oren, D. R. Arahal, and A. Ventosa Emended descriptions of genera of the family Halobacteriaceae Int J Syst Evol Microbiol, March 1, 2009; 59(3): 637 - 642. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |