INTERNATIONALJOURNAL OF SYSTEMATICBACTERIOLOGY, Apr., 1990, p. 209-210 Vol. 40. No. 2 0020-7713/90/020209-02$02.00/0 Copyright 0 1990, International Union of Microbiological Societies

Haloarcula marismortui (Volcani) sp. nov. nom. rev. an Extremely Halophilic Bacterium from the Dead Sea

A. OREN,l* M. GINZBURG,2 B. Z. GINZBURG,2 L. I. HOCHSTEIN,3 AND B. E. VOLCAN14 Division of Microbial and Molecular Ecology,’ and Plant Biophysical Laboratory,2 Institute of Life Sciences, The Hebrew University of Jerusalem, 91 904 Jerusalem, Israel; National Aeronautics and Space Administration Ames Research Center, Mofett Field, California 9403j3; and Scripps Institution of Oceanography, University of California, Sun Diego, La Jolla, California 920934

An extremely halophilic red archaebacterium isolated from the Dead Sea (Ginzburg et a]., J. Gen. Physiol. 55: 187-207,1970) belongs to the and differs sufficiently from the previously described of the genus to be designated a new species; we propose the name Haloarcula marismortui (Volcani) sp. nov., nom. rev. because of the close resemblance of this organism to “Halobacterium marismortui,” which was first described by Volcani in 1940. The type strain is strain ATCC 43049.

During his studies on the microbiology of the Dead Sea in served after electrophoresis of digests of DNA preparations the 1930s and 1940s Elazari-Volcani isolated a novel strain of with different restriction enzymes (ll), and although the the genus Halobacterium. This strain differed from the then DNA-DNA hybridization ratio of these organisms is rather known halobacterial types in its ability to form acid from low, the new isolate and strain ATCC 29715 appeared to be glucose, fructose, mannose, and glycerol and in its produc- related, as shown by the near identity of their 5s and 16s tion of gas from nitrate. The isolate was described as rRNAs and a large number of other common properties. “Halobacterium marismortui” (1, 15; B. Elazari-Volcani, However, there are distinct differences in cell morphology Ph.D. thesis, The Hebrew University of Jerusalem, 1940), and in the ability to utilize different sugars and other com- but was never deposited in a culture collection. As far as we pounds (11). Table 1 summarizes the differences between the know, the strain has been lost (6). new isolate and the previously validly described species in During the 1960s a new Halobacterium strain was isolated the genus Haloarcula. We consider these differences to be from the Dead Sea by Ginzburg et al. (3). This strain was sufficiently significant to warrant a separate species for the originally referred to as “Halobacterium of the Dead Sea.” new isolate. Morphologically, the Dead Sea isolate resem- However, the description of the new isolate closely resem- bles “Haloarcula californiae” (8), a species that was never bled the species description of “Halobacterium marismor- validly described. tui,” and Volcani himself agreed that the strain was similar The new isolate fits the original species description of to the original isolate (12). From 1978 on (2) the “Halobac- “Halobacterium marismortui” (l), except in the properties terium of the Dead Sea” was often called “Halobacterium described below. marismortui,” although it was never proposed as a neotype The original description of “Halobacterium marismortui” strain and was not deposited in a culture collection until mentions an optimum temperature of 30”C, and the new recently (as strain ATCC 43049* [T = type strain]) (6). Since isolate grows optimally at temperatures around 40 to 50°C no valid description has been published previously, since the (11). However, the publications of Volcani (1, 15; Elazari- old name continues to be invalid, and since in 1986 the Volcani, Ph.D. thesis) do not present evidence that growth Subcommittee on the of sug- experiments at temperatures above 30°C were attempted. gested that more studies were required to determine the Morphologically, the new isolate was described as having taxonomic position of this species (6), in this paper we flat disk-shaped or round, triangular, or square cells, and the remedy the situation by describing strain ATCC 43049T and original “Halobacterium marismortui” strain was described proposing a name. as nonmotile rods of variable length. In the micrographs of According to the new classification of the nonalkaliphilic Elazari-Volcani (Ph.D. thesis) rod-shaped cells are seen, but halophilic archaebacteria, the Dead Sea isolate belongs to most of the cells are irregular and resemble flat disks. the genus Haloarcula (5, 7, 14), as shown by its lipid The new isolate is generally described as nonmotile, and composition (both the Dead Sea isolate and members of the so was the original “Halobacterium marismortui” isolate. genus Haloarcula contain phosphatidylglycerol, phosphati- However, under special conditions a small number of the dylglycerol phosphate, phosphatidylglycerol sulfate, and cells of the new isolate were seen to actively rotate around glucosyl-mannosyl-glucosyldiether), 5s and 16s rRNA nu- their axes. cleotide sequences (ll), and ability to grow on simple carbon The new isolate did not produce acid from mannose sources (glucose, fructose, sucrose, glycerol, acetate, SUC- (although mannose stimulated growth) (ll), while the origi- cinate, and malate) (M. Mevarech, Tel Aviv University, nal “Halobacterium marismortui” strain reportedly pro- personal communication). Recently, a thorough comparison duced acid on mannose. On glucose, fructose, and glycerol was made of the new isolate (strain ATCC 43049T) and both isolates produced acid. Haloarcula vallismortis ATCC 29715 (4). Although the gua- A very slow and weak hydrolysis of starch was observed nine-plus-cytosine contents of the DNAs of these organisms with the new isolate, while the original “Halobacterium differ slightly, although very different patterns were ob- marismortui’ ’ strain reportedly did not hydrolyze starch. Because of the great resemblance between the new isolate and the lost organism “Halobacterium marismortui” (a * Corresponding author. name that has lost validity according to Rule 24a of the 209 210 NOTES INT. J. SYST.BACTERIOL.

TABLE 1. Comparison of strain ATCC 43049T with the previously validly described Haloarcula speciesn Acid Growth Guanine- Level of produced stimulation plus-cyto- DNA-DNA Cell size Starch from: by: sine con- hybridization Organism (w.4 MoVhologY Motility hydrolysis tent (major with strain Man- Sor- Succi- component) ATCC nitol bitol nate (mol%) 43049T (%)

~~ ~ Dead Sea isolate (strain 1-2 by 2-3 Pleomorphic, - - or very weak + + + + 62 100 ATCC 43049T) mostly flat disk shaped Haloarcula vallismortis 0.6-1 by 3-5 Irregular rods + + -- - - 65 39 Haloarcula hispanica 0.3 by 0.5-1 Short rods + + NR‘ NR + + 63 NR Data are from references 4, 9, 11, 13, and 14. Sometimes a small number of motile cells were observed. NR, Not reported.

International Code of Nomenclature of Bacteria [lo]), we intracellular concentrations. J. Gen. Physiol. 55187-207. propose the name Haloarcula marismortui (Volcani) sp. 4. Gonzalez, C., C. Gutierrez, and C. Ramirez. 1978. Halobacte- nov., nom. rev. rium vallisrnortis sp. nov. An amylolytic and carbohydrate- Haloarcula marismortui (Volcani) sp. nov., rev. metabolizing, extremely halophilic bacterium. Can. J. Micro- nom. Ha- biol. 24:710-715. loarcula marismortui (ma.ris.rn0r’tu.i. L. n. mare, the sea; 5. Grant, W. D., and H. Larsen. 1989. Group 111. Extremely L. gen. n. maris, of the sea; L. adj. mortuus, dead; M. L. halophilic archaeobacteria. Order ord. nov., p. gen. n. marismortui, of the Dead Sea). Cells are pleomor- 2216-2233. In J. T. Staley, M. P. Bryant, N. Pfennig, and J. G. phic, flat, and disk-shaped (1 to 2 by 2 to 3 Fm). Nonmotile Holt (ed.), Bergey’s manual of systematic bacteriology, vol. 3. (but rarely cells are observed to rotate around their axes). The Williams & Wilkins Co., Baltimore. Growth occurs in media containing 1.7 to 5.1 M NaCl 6. International Committee on Systematic Bacteriology Subcommit- (optimum NaCl concentration, 3.4 to 3.9 M). Optimum tee on the Taxonomy of Hulobacteriaceue. 1988. Minutes of the temperature, 40 to 50°C. meeting, 9 and 10 September 1986, Manchester, England. Int. J. Aerobic chemoorganotroph. Oxidase and catalase posi- Syst. Bacteriol. 38:332. 7. International Journal of Systematic Bacteriology. 1986. Valida- tive. Can grow anaerobically with nitrate as an electron tion of the publication of new names and new combinations acceptor. Utilizes a range of compounds as sole carbon and previously effectively published outside the IJSB. List no. 22. energy sources (glucose, fructose, sucrose, glycerol, ace- Int. J. Syst. Bacteriol. 36573-576. tate, succinate, and malate). Produces acid from glucose, 8. Javor, B., C. Requadt, and W. Stoeckenius. 1982. Box-shaped fructose, ribose, xylose, maltose, sucrose, mannitol, sorbi- halophilic bacteria. J. Bacteriol. 151:1532-1542. tol, and glycerol. Starch is very slowly hydrolyzed. Indole is 9. Juez, G., F. Rodriguez-Valera, A. Ventosa, and D. J. Kushner. not produced. Nitrate is reduced with production of gas and 1986. Haloarcula hispanica spec. nov. and Haloferax gibbonsii nitrite. Susceptible to bacitracin and novobiocin. spec. nov., two new species of extremely halophilic archaebac- Isolated from the Dead Sea. teria. Syst. Appl. Microbiol. 8:75-79. 10. Lapage, S. P., P. H. A. Sneath, E. F. Lessel, V. B. D. Skerman, The guanine-plus-cytosine content of the major DNA H. P. R. Seelinger, and W. A. Clark (ed.). 1975. International component is 62 mol%, and the guanine-plus-cytosine con- code of nomenclature of bacteria. 1975 Revision. American tent of the minor component is 55 mol%. Society for Microbiology, Washington, D. C. The type strain is strain ATCC 43049. 11. Oren, A., P. P. Lau, and G. E. Fox. 1988. The taxonomic status of “Halobacterium marismortui” from the Dead Sea: a com- We thank M. Mevarech (Tel Aviv University) for the contribution parison with Halobacterium vallismortis. Syst. Appl. Micro- of unpublished data. biol. 10:25 1-258. A.O. was supported by grants from the Israeli Ministry for Energy 12. Pundak, S., and H. Eisenberg. 1981. Structure and activity of and Infrastructure and the Hebrew University of Jerusalem Mutual malate dehydrogenase from the extreme halophilic bacteria of Fund. the Dead Sea. I. Conformation and interaction with water and salt between 5 M and 1M NaCl concentration. Eur. J. Biochem. LITERATURE CITED 118:463-470. Elazari-Volcani, B. 1957. Genus XII. Halobacterium Elazari- 13. Ross, H. N. M., and W. D. Grant. 1985. Nucleic acid studies on Volcani, p. 207-212. In R. S. Breed, E. G. D. Murray, and N. R. halophilic archaebacteria. J. Gen. Microbiol. 131:165-173. Smith (ed.), Bergey’s manual of determinative bacteriology, 7th 14. Torreblanca, M., F. Rodriguez-Valera, G. Juez, A. Ventosa, M. ed. The Williams & Wilkins Co., Baltimore. Kamekura, and M. Kates. 1986. Classification of non-alkaliphilic Ginzburg, M. 1978. Ion metabolism in whole cells of Halobac- halobacteria based on numerical taxonomy and polar lipid terium halobium and H. marismortui, p. 561-577. In S. R. composition, and description of Haloarcula gen. nov. and Caplan and M. Ginzburg (ed.), Energetics and structure of Haloferax gen. nov. Syst. Appl. Microbiol. 8:89-99. halophilic microorganisms. Elsevier/North-Holland Biomedical 15. Volcani, B. E. 1944. The microorganisms of the Dead Sea, p. Press, Amsterdam. 71-85. In Papers collected to commemorate the 70th anniver- Ginzburg, M., L. Sachs, and B. Z. Ginzburg. 1970. Ion metab- sary of Dr. Chaim Weizmann. Collective volume. Daniel Sieff olism in a Halobacterium. I. Influence of age of culture on Research Institute, Rehovoth.