| Author keywords | aerobe; extreme halophile; salt lake; saltern; square |
| Authors | | Top | - Rodríguez-Valera, F.
- Martin-Cuadrado, A.-B.
- Bolhuis, H., more
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| Abstract | Ha.lo.qua.dra'tum. Gr. masc. n. hals, halos salt, L. neut. n. quadratum square, N.L. neut. n. Haloquadratum salt square.Euryarchaeota / Halobacteria / Halobacteriales / HalobacteriaceaeThe haloarchaeal species Haloquadratum walsbyi, the only member described of the genus Haloquadratum, dominates NaCl saturated thalassic lakes worldwide. These microbes are unique due to their peculiar flattened and square shape (like a postage stamp), and they contain gas vesicles and granules of poly-β-hydroxyalkanoate. They are red-pink pigmented due to the presence of bacterioruberin carotenoids and bacteriorhodopsin. Reaching populations of up to 108 cells ml−1 they are the most successful halophile. However, pure cultures are extremely fastidious to obtain and grow very slowly in the laboratory. Even 10 years after the isolation of the first two strains, the existence of proven protocols for its isolation and its massive abundance in hypersaline ecosystems, only four more strains of Haloquadratum have been isolated. Most of the information available about this microbe derives from genome and metagenome sequencing. The genomes of the first two pure cultures indicate that they are photoheterotrophs like most members of the class Halobacteria. Their success may be due to the efficient exploitation of solar energy through rhodopsins and their large surface to volume ratio that would facilitate light and organic nutrient harvesting in the brine.DNA G + C content (mol%): 47.9Type species: Haloquadratum walsbyi. Burns, Janssen, Itoh, Kamekura, Li, Jensen, Rodríguez-Valera, Bolhuis and Dyall-Smith et al. 2007, 391VP |
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