Halomonas

Abstract: The morphological, biochemical, and physiological characteristics of nine bacterial strains isolated from a solar salt facility located on Bonaire, Netherlands Antilles are described. The bacteria were gram-negative rods which produce white, opaque colonies on solid media. During the log phase of growth, the cultures consisted of single and paired cells with polar flagella predominating. Older cultures characteristically produced highly elongated, flexible rods. All of these strains reduced NO3 to NO2, grew anaerobically in the presence of NO3, and fermented glucose but oxidized sucrose, glycerol, mannose, and cellobiose. All strains were ornithine and lysine decarboxylase positive, catalase positive, and cytochrome oxidase negative. Eight of the nine strains grew in a complex Casamino Acids liquid medium containing from 0 to 32% (wt/vol) solar salt at temperatures from 23 to 37°C; the ninth strain was restricted in its growth to 0 to 20% solar salt. The guanine plus cytosine content of the deoxyribonucleic acid was 61 ± 1 mol%. This combination of morphology, salt tolerance, and guanine plus cytosine content supports the establishment of a new genus, Halomonas, in Family II (Vibrionaceae) of part 8, Gram-Negative Facultatively Anaerobic Bacteria, of Bergey's Manual (8th edition). The type species of this genus is H. elongata, the type strain of which is isolate 1H9 (= ATCC 33173). Strain 1H15 is regarded as belonging to a biovar of H. elongata on the basis of its production of lophotrichous cells and its inability to grow at 37°c in the presence of 32% solar salt.

Abstract: Hypersaline environments with salt concentrations up to NaCl saturation are inhabited by a great diversity of microorganisms belonging to the three domains of life. They all must cope with the low water activity of their environment, but different strategies exist to provide osmotic balance of the cells' cytoplasm with the salinity of the medium. One option used by many halophilic Archaea and a few representatives of the Bacteria is to accumulate salts, mainly KCl and to adapt the entire intracellular machinery to function in the presence of molar concentrations of salts. A more widespread option is the synthesis or accumulation of organic osmotic, so-called compatible solutes. Here, we review the mechanisms of osmotic adaptation in a number of model organisms, including the KCl accumulating Halobacterium salinarum (Archaea) and Salinibacter ruber (Bacteria), Halomonas elongata as a representative of the Bacteria that synthesize organic osmotic solutes, eukaryotic microorganisms including the unicellular green alga Dunaliella salina and the black yeasts Hortaea werneckii and the basidiomycetous Wallemia ichthyophaga, which use glycerol and other compatible solutes. The strategies used by these model organisms and by additional halophilic microorganisms presented are then compared to obtain an integrative picture of the adaptations to life at high salt concentrations in the microbial world.

Abstract: Foreword J. Seckbach Introduction N. Gunde-Cimerman, A. Oren, A. Plemenitas SECTION I. THE ENVIRONMENTS AND THEIR DIVERSITY Microbial diversity of Great Salt Lake B.K. Baxter, C.D. Litchfield, K. Sowers, J.D. Griffith, P.A. DasSarma S. DasSarma Microbial communitites in the Dead Sea - past, present and future A. Oren, I. Gavrieli, J. Gavrieli, M. Kohen, J. Lati, M. Aharoni Microscopic examination of microbial communitires along a salinity gradient in saltern evaporation poonds: a 'halophilic safari' A. Oren The microbial diversity of a solar saltern on San Francisco Bay C.D. Litchfield, M. Sikaroodi, P.M. Gillivet Diversity of microbial communities: the case of solar salterns C. Pedros-Alio Isolation of viable haloarchaea from ancient salt deposits and application of fluorescent stains for in situ detection of halophiles in hypersaline environmental samples and model fluid inclusions S. Leuko, A. Legat, S. Fendrihan, H. Wieland, C. Radax, C. Gruber, M. Pfaffenhuemer, G. Weidler, H. Stan-Lotter Hydrocarbon degredation under hypersaline conditions. Some facts, some experiments and many open questions H. Patzelt The relevance of halophiles and other extremophiles to Martian and extraterrestrial environments J. Seckbach Halophiles: a terrestrial analog for life in brines on Mars - Halophiles on Mars R.L. Mancinelli SECTION II. ARCHAEA Comparative genomic survey of information transfer systems in two diverse extremely halophilic Archaea, Halobacterium sp. strain NRC-1 and Haloarcula marismortui B.R. Berquist, J. Soneja, S. DasSarma Walsby's square archaeon it's hip to be square but even more hip to be culturable H. Bolhuis Gene regulation and the initiation of translation inhalophilic Archaea F. Pfeifer, P. Zimmermann, S. Scheuch, S. Sartorius-Neef Protein translation, targeting and translocation in Haloferax volcanii J. Eichler, G. Ring, V. Irihimovitch, T. Lichi, I. Tozik, Z. Konrad Enzymes of halophilic Archaea. Recent findings on ureases and nucleoside diphosphate kinases T. Mizuki, R. Usami, M. Kamo, M. Tanokura, M. Kamekura Osmoadaptation in methanogenci Archaea: recent insights from a genomic perspective K. Pfluger, H. Wieland, V. Muller SECTION III. BACTERIA Salinibacter ruber: genomics and biogeography J. Anton, A. Pena, M. Valens, F. Santos, F.-O. Glockner, M. Bauer, J. Dopazo, J. Herrero, R. Rossello-Mora, R. Amann What we can deduce about metabolism in the moderate halophile Chromohalobacter salexigens from its genomic sequence L.N. Csonka, K. O'Connor, F. Larimer, P. Richardson, A. Lapidus, A.D. Ewing, B.W. Goodner, A. Oren K+ transport and its role for osmoregulation in a halophilic memberof the Bacteria domain: characterization of the K+ uptake systems from Halomonas elongate H.-J. Kunte The chloride regulon of Halobacillus halophilus: a novel regulatory network for salt perception and signal transduction in bacteria V. Muller, S.H. Saum Biosynthesis of the compatible solute mannosylglycerate from hyperthermophiles to mesophiles. Genes, enzymes and evolutionary perspectives M.S. da Costa, N. Empadinhas Genes and enzymes of ectoine biosynthesis in the haloalkaliphilic obligate methanotroph 'Methylomicrobium alcaliphilum 20Z' A.S. Reshetnikov, V.N. Khmelenina, I.I. Mustakhimov, Y.V. Ryzhmanova, Y.A. Trotsenko Halophilic Archaea and Bacteria as a source of extracellular hydrolytic enzymes A. Ventosa, C. Sanchez-Porro, S. Martin, E.