Mol Microbiol, 1993 Mar, 7(6), 875 - 82 Antisense RNA mediates transcriptional processing in an archaebacterium, indicating a novel kind of RNase activity; Stolt P et al.; Strains of the extremely halophilic archaebacterium Halobacterium salinarium that are lysogenic for the phage phi H produce an antisense RNA transcript complementary to the first 151 nucleotides (nt) of the early lytic phage transcript T1 . This is the first case of antisense control of gene expression in an archaebacterium . We show through transformation of H . salinarium that the antisense RNA functions in trans, rendering the early lytic phage transcript T1 susceptible to specific cleavage by an unidentified RNase of unique endonucleolytic activity . The single-stranded ends of RNA are cut off at the ends of the 151 nt RNA duplex, removing the ribosomal binding sites from the first open reading frame of transcript T1 but without concomitant digestion of the products. Eur J Biochem, 1993 Feb 15, 212(1), 69 - 78 1H-NMR investigation of oxidized and reduced high-potential iron-sulfur protein from Rhodopseudomonas globiformis; Bertini I et al.; 1H one-dimensional and two-dimensional NMR spectra have been recorded for the oxidized and reduced forms of the high-potential iron-sulfur protein (HiPIP) from Rhodopseudomonas globiformis which has the highest known reduction potential . The spectrum of the oxidized protein is similar to that of Chromatium vinosum and Rhodocyclus gelatinosus HiPIP but different from that of the HiPIP II from Ectothiorhodospira halophila . Surprisingly, site-specific assignment has shown that in the oxidized protein the distribution of oxidation numbers within the cluster is very similar to that found for E . halophila HiPIP II and different from that of the other two proteins . The spectrum of the reduced species is very similar to that of all other HiPIPs known to date, indicating very similar electronic and geometric structures for the reduced forms . These findings are discussed in terms of cluster structure in HiPIPs and of redox potentials. Can J Microbiol, 1993 Feb, 39(2), 259 - 62 Levels of small molecules in dormant spores of Sporosarcina species and comparison with levels in spores of Bacillus and Clostridium species; Loshon CA et al.; Dormant spores of Sporosarcina halophila and Sporosarcina ureae contained no detectable ATP, significant levels of ADP, even higher levels of AMP, and a large pool of 3-phosphoglyceric acid, similar to what is found in dormant spores of Bacillus and Clostridium species . Sporosarcina halophila and S . ureae spores also contained significant pools of free amino acids, in particular glutamic acid, as in the case with spores of Bacillus but not Clostridium species . Levels of monovalent and divalent inorganic cations were comparable in spores of Sporosarcina, Clostridium, and Bacillus species, and cation levels in spores of the slight halophile S . halophila were similar to those in S . ureae spores . These data suggest that levels of small molecules are generally similar in spores of all Gram-positive organisms, and further suggest that these levels reflect fundamental and conserved features of the sporulation process and dormant spores in these organisms . The data are also consistent with the proposed close evolutionary relationship between Bacillus and Sporosarcina species. J Appl Bacteriol, 1993 Feb, 74(2), 164 - 9 Interactions among xerophilic fungi associated with dried salted fish; Wheeler KA et al.; Interactions were investigated among five xerophilic fungi, Polypaecilum pisce, Basipetospora halophila, Eurotium rubrum, Aspergillus wentii and A . penicillioides, isolated from Indonesian dried salted fish . A range of water activities (aw) (0.98, 0.95, 0.90 and 0.84) and temperatures (15 degrees, 25 degrees and 30 degrees C) were studied on agar media in Petri dishes, and with dried fish as a substrate at 0.90 and 0.84 aw at 30 degrees C . Generally, the fungi exhibited one of two interaction types: mutual inhibition on contact, or inhibition of one or both species on contact, with the inhibited species continuing to grow at a significantly reduced rate . On glucose-based agar media A . wentii and E . rubrum were most competitive at all aw values and temperatures studied, while on NaCl media P . pisce and B . halophila were usually most competitive . The Petri dish system was a useful model, but did not completely simulate the interactions observed on dried fish . Polypaecilum pisce and B . halophila were able to compete more strongly on fish than on agar media, especially at 0.90 aw . This study provides some evidence that each species examined had a niche in which it was dominant, and that species interactions as well as environmental factors are important in determining the dominant fungal species on dried salted fish. J Bacteriol, 1993 Feb, 175(3), 684 - 92 The rightward gas vesicle operon in Halobacterium plasmid pNRC100: identification of the gvpA and gvpC gene products by use of antibody probes and genetic analysis of the region downstream of gvpC; Halladay JT et al.; The extreme halophile Halobacterium halobium synthesizes intracellular gas-filled vesicles that confer buoyancy . A cluster of 13 genes on the 200-kb endogenous plasmid pNRC100 has been implicated in the biosynthesis of gas vesicles . Here, we show that two gas vesicle proteins are encoded by genes in the rightward operon, gvpA and gvpC, by Western blotting (immunoblotting) analysis with antibodies directed against LacZ-GvpA and LacZ-GvpC fusion proteins . Our results are consistent with previous data showing that the gvpA gene product is the major gas vesicle protein and demonstrate for the first time that the gvpC gene product is also present in H . halobium gas vesicles . Northern (RNA) blotting analysis showed two RNA species, an abundant 0.35-kb transcript of gvpA and a minor 2.5-kb transcript of gvpAC, and a third gene 3' to gvpAC, named gvpN . The gvpN gene encodes a hypothetical acidic protein with a molecular weight of 39,000 and a nucleotide binding motif . We used a site-directed mutagenesis method involving double recombination in Escherichia coli to insert a kanamycin resistance cassette just beyond the stop codon of gvpN . Introduction of the mutated gene cluster into an H . halobium mutant with a deletion of the entire gas vesicle gene cluster resulted in gas vesicle-positive transformants; this result suggests that gvpN is the last gene of the rightward gas vesicle transcription unit . We discuss the design and utility of the kanamycin resistance cassette for the mutagenesis of other genes in large operons. J Bacteriol, 1993 Feb, 175(4), 1081 - 6 Heterogeneity of small plasmids from halophilic archaea; Akhmanova AS et al.; Small multicopy plasmids in three strains of halophilic archaea, SB3, GRB, and GN101, were found to be present in a cell as a population of related but not identical sequences . Two types of heterogeneity were observed: macroheterogeneity, represented by two major plasmid sequence versions homologous to each other by 80%, and microheterogeneity, in which individual plasmids differ by one or a few nucleotide substitutions. Biochemistry, 1993 Jan 26, 32(3), 791 - 8 Halophilic class I aldolase and glyceraldehyde-3-phosphate dehydrogenase: some salt-dependent structural features; Krishnan G et al.; Aldolase and glyceraldehyde-3-phosphate dehydrogenase from the extremely halophilic archaebacterium Haloarcula vallismortis are stable only in high concentrations of KCl present within the physiological environment . Data concerning the structural changes in the two enzymes as a result of lowering of salt concentration and changes in pH were obtained by monitoring the intrinsic protein fluorescence in the presence of quenchers . When the KCl concentrations were lowered below 2 M or in the presence of 6 M guanidine hydrochloride, the emission maximum shifted to a longer wavelength, indicating enhanced exposure of tryptophyl residues to the solvent . The spectral characteristics of the two proteins in guanidine hydrochloride and 0.4 M KCl were identical . However, these denatured states appear to be different than those observed after acid denaturation . Further perturbation of fluorescence was observed due to I-, and application of the Stern-Volmer law showed that the total fluorescence was available to the quenchers only in 0.4 M KCl solutions . The unfolding of proteins in 0.4 M KCl was a gradual process which was accompanied by a time-dependent loss in enzyme activity . The activity loss was complete within 30 min for aldolase whereas in the case of GAPDH nearly 3 h was required for the destruction of activity . For both enzymes, inactivation and protein denaturation were strongly correlated . The data on activity and thermostability measurements of the two enzymes in varying concentrations of KCl and potassium phosphate revealed that though both proteins are halophilic, the forces in the maintenance of their stability could be different.(ABSTRACT TRUNCATED AT 250 WORDS) J Bacteriol, 1993 Jan, 175(1), 299 - 302 Tryptophan biosynthesis genes trpEGC in the thermoacidophilic archaebacterium Sulfolobus solfataricus; Tutino ML et al.; A DNA fragment containing the trpEGC gene cluster was isolated from the thermoacidophilic archaebacterium Sulfolobus solfataricus . The products of trpE, trpG, and trpC from S . solfataricus were compared to the homologous products from a eukaryote, a eubacterium, and two archaebacteria, namely, a methanogen and an extreme halophile . They appeared to be equally related to the proteins from Escherichia coli and Saccharomyces cerevisiae, the percentages of conserved amino acids being roughly the same as those measured when comparing the eubacterial and eukaryotic sequences directly . These percentages did not rise significantly when a comparison with the proteins from Haloferax volcanii was drawn, while a slightly closer relationship with the proteins from Methanococcus thermoautotrophicum was found. Arch Microbiol, 1993, 160(1), 5 - 11 Characterization of the glyceraldehyde 3-phosphate dehydrogenase from the extremely halophilic archaebacterium Haloarcula vallismortis; Pruss B et al.; Glyceraldehyde 3-phosphate dehydrogenase (EC 1.2.1.12) from the extremely halophilic archaebacterium Haloarcula vallismortis has been purified in a four step procedure to electrophoretic homogeneity . The enzyme is a tetramer with a relative molecular mass of 160,000 . It is strictly NAD(+)-dependent and exhibits its highest activity in 2 mol/l KCl at 45 degrees C . Amino acid analysis and isoelectric focusing indicate an excess of acidic amino acids . Two parts of the primary sequence are reported . These peptides have been compared with glyceraldehyde 3-phosphate dehydrogenases from other archaebacteria, eubacteria and eucaryotes . The peptides show a high grade of similarity to glyceraldehyde 3-phosphate dehydrogenase from eucaryotes. Scand J Infect Dis, 1993, 25(6), 735 - 40 Extraintestinal infections caused by Vibrio parahaemolyticus and Vibrio alginolyticus in a Danish county, 1987-1992; Hornstrup MK et al.; Over a 6-year period we detected 30 clinical infections caused by halophilic vibrios in a restricted geographical area . Vibrio parahaemolyticus infections were found in 13 patients (3 with wound infections, 10 with ear infections), and Vibrio alginolyticus infections in 17 patients, all of whom had ear infections . From 1987 to 1990, infections caused by marine vibrios were found in at most 4 cases annually, in 1992 in 6 instances, whereas in a 5-month period in 1991 we experienced 15 cases of extra-intestinal infections . 15 of the infections found in 1991 and 1992 were ear infections, 10 of which occurred shortly after exposure to Danish coastal seawater . The disease was mild in most of the patients and all recovered . Most of the patients showed predisposing conditions such as chronic otitis media, perforation of the tympanic membrane or ulcus cruris . The organisms were isolated in minor numbers from coastal water samples from 5 of 12 bathing areas around Funen at the end of July, but not at the end of November . This study indicates that the halophilic marine vibrios may be pathogenic in Scandinavian areas in persons exposed to seawater. Proc Natl Acad Sci U S A, 1992 Dec 15, 89(24), 11915 - 9 Primary structure of an archaebacterial transducer, a methyl-accepting protein associated with sensory rhodopsin I; Yao VJ et al.; A methylated membrane protein of 97 kDa was suggested on the basis of mutant analysis to transduce signals from the phototaxis receptor sensory rhodopsin I to the flagellar motor in Halobacterium halobium . Here we report isolation of the proposed transducer protein, cloning of its gene based on partial protein sequences, the complete gene sequence, and analysis of the encoded primary structure . The 1611-base-pair gene termination codon overlaps the initiator ATG of the sopI gene, which encodes the sensory rhodopsin I apoprotein . The predicted size of 57 kDa for the methylated protein indicates an aberrant electrophoretic migration on SDS/polyacrylamide gels, as occurs with other acidic halophilic proteins . Putative promotor elements are located in an A+T-rich region upstream of the gene . Comparison of the translated nucleotide sequence with N-terminal sequence of the purified protein shows the protein is synthesized without a processed leader peptide and the N-terminal methionine is removed in the mature protein . The deduced protein sequence predicts two transmembrane helices near the N terminal that would anchor the protein to the membrane . Beyond this hydrophobic region of 46 residues, the remainder of the protein (536-amino acid residues total) is hydrophilic . The C-terminal 270 residues contain a region homologous to the signaling domains of eubacterial transducers (e.g., Escherichia coli Tsr protein), flanked by two regions homologous to the methylation domains of the transducer family . The protein differs from E . coli Tsr in that it does not have an extramembranous-receptor binding domain but instead has a more extended cytoplasmic region . Coexpression of the methyl-accepting protein gene (designated htrI) and sopI restores sensory rhodopsin I phototaxis to a mutant (Pho81) that contains a deletion in the htrI/sopI region . These results extend the eubacterial transducer family to the archaebacteria and substantiate the proposal that the methylated membrane protein functions as a signal-transducing relay between sensory rhodopsin I and cytoplasmic sensory-pathway components. J Bioenerg Biomembr, 1992 Dec, 24(6), 577 - 85 Function and biosynthesis of gas vesicles in halophilic Archaea; Pfeifer F et al.; The proteinaceous gas vesicles produced by various microorganisms including halophilic Archaea are hollow, gas-filled structures with a hydrophobic inner and a hydrophilic outer surface . The structural components of gas vesicles and their biosynthesis are still under investigation; an 8-kDa polypeptide appears to be the major constituent of the gas-vesicle envelope . Genetic analysis of the halobacterial gas-vesicle synthesis revealed an unexpected complexity: about 14 genes organized in three transcription units are involved in gas-vesicle structure, assembly, and gene regulation . Here we describe the comparison of three different genomic regions encoding gas vesicles in Halobacterium salinarium (p-vac and c-vac regions) and Haloferax mediterranei (mc-vac region) and speculate on the function of the gene products involved in gas-vesicle synthesis. Biochem Int, 1992 Dec, 28(4), 633 - 41 Involvement of thiol groups in the reaction mechanism of Mn(2+)-activated alkaline p-nitrophenylphosphate phosphatase of the extreme halophilic archaebacterium Halobacterium halobium; Bonet ML et al.; Halobacterium halobium contains a cytosolic alkaline p-nitrophenylphosphate phosphatase which is selectively activated by Mn2+ ions (Bonet et al., 1991: Int . J . Biochem . 12, 1445-1451) . We investigated the reaction mechanism of the enzyme in the presence and the absence of Mn2+ by means of pH studies and the application of some group-specific reagents . A pKes 8.4 of a group in the Mn(2+)-enzyme-substrate complex involved in catalysis could not be detected when catalysis in the absence of the cation was analysed . Only the enzyme with bound Mn2+ was inhibited by p-hydroxymercuribenzoate . Reducing agents stimulated the Mn(2+)-dependent activity but had no effect on the native enzyme activity . Our results indicate that the reaction mechanism is different whether the activating cation is present or not, and that the reaction mechanism in the presence of Mn2+ involves thiol groups. Mol Microbiol, 1992 Dec, 6(23), 3543 - 50 Functional analysis of the gas vesicle gene cluster of the halophilic archaeon Haloferax mediterranei defines the vac-region boundary and suggests a regulatory role for the gvpD gene or its product; Englert C et al.; A series of deletions introduced into the gvp gene cluster of Haloferax mediterranei, comprising 14 genes involved in gas vesicle synthesis (mc-vac-region), was investigated by transformation experiments . Gas vesicle production and the expression of the gvpA gene encoding the major gas vesicle protein, GvpA, was monitored in each Haloferax volcanii transformant . Whereas transformants containing the entire mc-vac-region produced gas vesicles (Vac+), various deletions in the region 5' to gvpA (encompassing gvpD-gvpM) or 3' to gvpA (containing gvpC, gvpN and gvpO) revealed Vac- transformants . All these transformants expressed gvpA and contained the 8 kDa GvpA protein as shown by Western analysis . However, transformants containing the gvpA gene by itself indicated a lower level of GvpA than observed with each of the other transformants . None of these transformants containing deletion constructs assembled the GvpA protein into gas vesicles . In contrast, transformants containing a construct carrying a 918 bp deletion internal to gvpD exhibited a tremendous gas vesicle overproduction, suggesting a regulatory role for the gvpD gene or its product . This is the first assignment of a functional role for one of the 13 halobacterial gvp genes found in addition to gvpA that are involved in the synthesis of this unique structure. J Mol Biol, 1992 Nov 20, 228(2), 672 - 86 Three-dimensional structure of the high-potential iron-sulfur protein isolated from the purple phototrophic bacterium Rhodocyclus tenuis determined and refined at 1.5 A resolution; Rayment I et al.; The molecular structure of the high-potential iron-sulfur protein (HiPIP) isolated from the phototrophic bacterium, Rhodocyclus tenuis, has been solved and refined to a nominal resolution of 1.5 A with a crystallographic R-factor of 17.3% for all measured X-ray data from 30 A to 1.5 A . It is the smallest of the HiPIP structures studied thus far with 62 amino acid residues . Crystals used in the investigation belonged to the space group P2(1) with unit cell dimensions of a = 36.7 A, b = 52.6 A, c = 27.6 A and beta = 90.8 degrees and contained two molecules per asymmetric unit . The structure was solved by a combination of multiple isomorphous replacement with two heavy-atom derivatives, anomalous scattering from the iron-sulfur cluster, symmetry averaging and solvent flattening . The folding motif for this HiPIP is characterized by one small alpha-helix, six Type I turns, an approximate Type II turn and one Type I' turn . As in other HiPIPs, the iron-sulfur cluster is co-ordinated by four cysteinyl ligands and exhibits a cubane-like motif . These cysteinyl ligands are all located in Type I turns . The hydrogen bonding around the metal cluster in the R . tenuis protein is similar to the patterns observed in the Chromatium vinosum and Ectothiorhodospira halophila HiPIPs . Several of the amino acid residues invariant in the previously determined C . vinosum and E . halophila structures are not retained in the R . tenuis molecule . There are 13 solvent molecules structurally conserved between the two R . tenuis HiPIP molecules in the asymmetric unit, some of which are important for stabilizing surface loops . Interestingly, while it is assumed that this HiPIP functions as a monomer in solution, the two molecules in the asymmetric unit pack as a dimer and are related to each other by an approximate twofold rotation axis. J Bacteriol, 1992 Nov, 174(22), 7474 - 7 Glycine betaine and potassium ion are the major compatible solutes in the extremely halophilic methanogen Methanohalophilus strain Z7302; Lai MC et al.; Methanohalophilus strain Z7302 was previously isolated from a hypersaline environment and grows over a range of NaCl concentrations from 1.7 to 4.4 M . We examined the relationships between cell growth rate, cell volume, and intracellular solute concentrations with increasing salinity . This extremely halophilic methanogen synthesized three zwitterionic compounds, beta-glutamine, N epsilon-acetyl-beta-lysine, and glycine betaine, and also accumulated potassium ion as compatible solutes to balance the external and internal osmotic pressures . Potassium and glycine betaine were the predominant compatible solutes when Methanohalophilus strain Z7302 was grown at high external NaCl concentrations and approached intracellular levels of 3 and 4 M, respectively. J Bacteriol, 1992 Nov, 174(22), 7207 - 16 Chromosomal structure of the halophilic archaebacterium Halobacterium salinarium; Takayanagi S et al.; The chromosomal structure of the extremely halophilic archaebacterium Halobacterium salinarium was examined . Sheared chromosomes prepared from the bacteria in the late exponential phase were separated into two peaks (peaks I and II) by sucrose gradient centrifugation, suggesting that the chromosomes consist of two parts differing in quality . The UV spectra of peaks I and II resembled those of DNA and eukaryotic chromatin, respectively . Electron microscopic observations revealed that the major component of peak I was protein-free DNA, while the major components of peak II were rugged thick fibers with a diameter of 17 to 20 nm . The rugged fibers basically consisted of bacterial nucleosome-like structures composed of DNA and protein, as demonstrated in experiments with proteinase and nuclease digestion . Whole-mount electron microscopic observations of the chromosomes directly spread onto a water surface revealed a configuration in which the above-described regions were localized on a continuous DNA fiber . From these results it is concluded that the H . salinarium chromosome is composed of regions of protein-free DNA and DNA associated with nucleosome-like structures . Peaks I and II were predominant in the early exponential phase and stationary phase, respectively; therefore, the transition of the chromosome structure between non-protein-associated and protein-associated forms seems to be related to the bacterial growth phase. Gig Sanit, 1992 Nov-Dec, (11-12), 33 - 5 {Risk of halophilic morbidity in connection with the eutrophication of the seashore}; Korchak GI et al.; Significant role of the littoral eutrophication in the growth of parahemolytic vibrio caused acute gastrointestinal disturbance- halophilosis was described. Biochim Biophys Acta, 1992 Oct 5, 1110(2), 171 - 7 Archaebacterial lipid models: highly salt-tolerant membranes from 1,2-diphytanylglycero-3-phosphocholine; Yamauchi K et al.; 1,2-Di(3RS,7R,11R-phytanyl)-sn-glycero-3-phosphocholine and its glycerol epimers were synthesized as model lipids of archaebacterial halophiles . These amphiphiles, upon sonication of aqueous suspensions, gave rise to small unilamellar vesicles (SUV) of 300-800 A in diameter and about 80 A in the membrane thickness . The liposomes were very stable for at least a month even in a highly concentrated suspension or 5 M aqueous NaCl . The vesicles could retain Na+ and Cl- ions as well as 5(6)-carboxyfluorescein in the aqueous interior at temperature as high as 70 degrees C . The liposomes of ordinary diester lipids such as 1,2-dipalmitoyl-sn-glycero-3-phosphocholine and egg-yolk lecithin were less stable and more permeable than those of the diphytanyl lipids. Gene, 1992 Sep 21, 119(1), 131 - 6 Genetic transformation of a halophilic archaebacterium with a gas vesicle gene cluster restores its ability to float; Halladay JT et al.; The halophilic archaebacterium, Halobacterium halobium, and many other aquatic bacteria synthesize gas-filled vesicles for flotation . We recently identified a cluster of 13 genes (gvpMLKJIHGFEDACN) on a 200-kb H . halobium plasmid, pNRC100, involved in gas vesicle synthesis . We have cloned and reconstructed the gvp gene cluster on an H . halobium-E . coli shuttle plasmid . Transformation of H . halobium Vac- mutants lacking the entire gas vesicle gene region with the gvp gene cluster results in restoration of their ability to float . These results open the way toward further genetic analysis of gas vesicle gene functions and directed flotation of other microorganisms with potential biotechnological applications. J Mol Biol, 1992 Sep 20, 227(2), 586 - 92 Three different but related gene clusters encoding gas vesicles in halophilic archaea; Englert C et al.; We present an analysis of the chromosomal region comprising the gene cluster involved in gas vesicle (Vac) synthesis in Haloferax mediterranei (mc-vac-region) and Halobacterium salinarium (c-vac-region) and compare both of them to the plasmid located p-vac-region of H . salinarium . The p-vac-region of 9000 base-pairs (9 kb) is more related to mc-vac (9.4 kb) of Hf . mediterranei than it is to the c-vac-region (8.3 kb) present in the same cell . The Vac- species Hf . volcanii becomes Vac+ following transformation with a fragment containing the entire mc-vac-region . Also the p-vac-region transforms Hf . volcanii to a Vac+ phenotype, indicating that this gene cluster is sufficient for gas vesicle synthesis and does not depend on products of the c-vac-region . Each of these vac-regions contains, in addition to gvpA encoding the major gas vesicle protein, 13 open reading frames named gvpC through gvpO . Ten of these, gvpD through gvpM, are located upstream from gvpA in opposite orientation, while gvpC, gvpN and gvpO are found 3' to gvpA . The absolute requirement of gvpO for gas vesicle synthesis was demonstrated by transformation experiments . Northern analyses with RNA samples isolated during the growth cycle of Hf . mediterranei or of H . salinarium PHH4 revealed that the mc-gvpD or c-gvpD mRNAs occur similar to the respective gvpA mRNA in stationary growth phase, while gvpF-gvpM are transcribed mainly during logarithmic growth . S1-nuclease mapping was performed to determine the transcriptional start site of the gvpD mRNA . The distance between the two divergent start sites of gvpA and gvpD mRNA is 109 base-pairs in mc-vac and p-vac, while in the case of c-vac this distance is 22 base-pairs larger . The conservation of the various gvp products, characteristic features and their possible functions in gas vesicle synthesis are discussed. Trends Biotechnol, 1992 Sep, 10(9), 315 - 23 Biotechnology of the Archaea; Cowan DA; The Archaea, designated since 1979 as a separate Super-Kingdom (the highest taxonomic order), are a highly novel group of microorganisms which look much like bacteria but have many molecular and genetic characteristics that are more typical of eukaryotes . These unusual organisms can be conveniently divided according to their 'extreme' environmental niche, into three broad phenotypes: the thermophiles, methanogens and extreme halophiles . Each group has unique biochemical features which can be exploited for use in the biotechnological industries . The extreme molecular stability of thermophile enzymes, the novel C1 pathways of the methanogens and the synthesis of organic polymers by some halophiles are all currently or potentially valuable examples of the biotechnology of the Archaea. J Bacteriol, 1992 Aug, 174(15), 5027 - 35 Osmoprotection of Escherichia coli by ectoine: uptake and accumulation characteristics; Jebbar M et al.; Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) is a cyclic amino acid, identified as a compatible solute in moderately halophilic bacteria . Exogenously provided ectoine was found to stimulate growth of Escherichia coli in media of inhibitory osmotic strength . The stimulation was independent of any specific solute, electrolyte or nonelectrolyte . It is accumulated in E . coli cells proportionally to the osmotic strength of the medium, and it is not metabolized . Its osmoprotective ability was as potent as that of glycine betaine . The ProP and ProU systems are both involved in ectoine uptake and accumulation in E . coli . ProP being the main system for ectoine transport . The intracellular ectoine pool is regulated by both influx and efflux systems. Can J Microbiol, 1992 Aug, 38(8), 823 - 7 Interactive effects of salt concentration and temperature on growth and lipid composition in the moderately halophilic bacterium Vibrio costicola; Adams RL et al.; The interactive effects of NaCl concentration and growth temperature on the growth and lipid composition of the moderately halophilic eubacterium Vibrio costicola have been investigated . Vibrio costicola was shown to be capable of growth over the temperature range 4-37 degrees C . Maximum growth yields were obtained at 30 degrees C when the optimum NaCl concentration was 1.0 M NaCl . In contrast with some previous studies, at higher or lower growth temperatures both the optimum and lower limit of NaCl concentration were higher, but there was no change in the upper limit of NaCl concentration for growth . There were no differences between the lipid compositions of cultures grown in 1 M NaCl at 30 or 37 degrees C, but as the growth temperature was lowered from 30 to 10 or 4 degrees C, the ratio of phosphatidylethanolamine to phosphatidylglycerol increased significantly as a result of the conversion of phosphatidylglycerol to diphosphatidylglycerol; in addition, at the lower growth temperatures the phospholipid fatty acyl composition became more unsaturated and the mean acyl chain length was shorter . It is suggested that the altered salt dependence of V . costicola at temperatures below the optimum for growth is due to a modification in membrane lipid phase behavior and stability brought about by changes in lipid composition, whereas a different mechanism operates above the growth temperature optimum. Biopolymers, 1992 Aug, 32(8), 981 - 92 Conformational studies of anionic melittin analogues: effect of peptide concentration, pH, ionic strength, and temperature--models for protein folding and halophilic proteins; Ramalingam K et al.; Melittin (MLT), a 26-residue cationic (net charge +5 at pH 7.2) peptide from bee venom, is well known to be a monomeric, approximately random coil; but when its charges are reduced by titration, by acetylation (net charge +2) or succinylation (net charge -2), or by screening by salt, it goes over to tetrameric alpha-helix . The conversion is promoted by raising the peptide concentration . The tetramer is held together by hydrophobic forces . We have changed the net charge to -6 by acylation with acetylcitric anhydride (a new acylating agent); this anionic derivative forms tetrameric helix at neutral pH, without salt, and at relatively low concentration, conditions under which the cationic MLT does not become helical . Thus, a high net charge is not sufficient to prevent association and helix formation . We have synthesized an anionic melittin analogue of MLT (E-MLT; net charge -4) in which all five lysine and arginine residues are replaced with glutamate, and acetyl and succinyl derivatives of E-MLT (net charges -5 and -6) . All three of these are resistant to helix formation . They require much higher NaCl or NaClO4 concentration for helix formation than does MLT . Even CaCl2, MgCl2, and spermine.4HCl are less effective in helicizing E-MLT than MLT . MLT, at pH 7.2, shows increasing helix as the peptide concentration increases (8-120 microM), but E-MLT and its acyl derivatives do not . MLT and acylated MLTs in the helical tetramer show both cold- and heat-induced unfolding, with maximum stability near room temperature . At high temperature, a significant amount of residual structure remains . Heating (to 100 degrees C) monomeric MLT (i.e., MLT at low concentration) or E-MLT results in a monotonic increase in negative ellipticity . In 1.0 M NaCl, E-MLT (at sufficiently high concentration) also shows cold and hot unfolding . The results are discussed in respect to charge-charge and charge-dipole interactions, and hydrophobic effects . E-MLT is also discussed in relation to proteins of halophilic bacteria, which have higher proportions of anionic residues than do corresponding proteins of nonhalophiles. Biokhimiia, 1992 Aug, 57(8), 1230 - 41 {Serine proteinase from the archaebacterium Halobacterium mediterranei--an analog of eubacterium subtilisin}; Rudenskaia GN et al.; A homogeneous serine proteinase was isolated from cultural filtrates of the extreme halophilic bacteria Halobacterium mediterranei 1538 using affinity chromatography on bacitracin-Sepharose, ultrafiltration and gel filtration on Sephadex G-75, with a 48% yield and 260-fold purification . The enzyme was completely inactivated by specific inhibitors of serine proteinases, PMSF and DFP, as well as by Hg2+ and PCMB . The enzyme activity was strongly dependent of NaCl concentration, the enzyme being inactivated below 0.75 M NaCl . Inactivation of the enzyme was also seen in the presence of 2-7% organic solvents . The pH optimum for Glp-Ala-Ala-Leu-pNA hydrolysis is 8.0-8.5; Km is 0.14 mM, kcat is 36.9 s-1 . The stability optimum lies at pH 5.5-8.0, temperature optimum is at 55 degrees C . The enzyme molecular weight is 41,000 Da; pI is 7.5 . The substrate specificity of the enzyme is comparable to that of secretory subtilisins; the extent of protein substrate hydrolysis is similar to that of proteinase K . The N-terminal sequence of Halobacterium mediterranei serine proteinase, Asp-Thr-Ala-Asn-Asp-Pro-Lys-Tyr-Gly-Ser-Gln-Tyr-Ala-Pro-Gln-Lys-Val-Asn- Ala- Asp-, reveals a 50% homology with the aminoterminal sequence of Thermoactinomyces vulgaris serine proteinase . Hence, the serine proteinase secreted by halophilic bacteria may be considered as a structural and functional analog of eubacterial enzymes. Biochem Cell Biol, 1992 Aug, 70(8), 656 - 63 Dihydrolipoamide dehydrogenase from Haloferax volcanii: gene cloning, complete primary structure, and comparison to other dihydrolipoamide dehydrogenases; Vettakkorumakankav NN et al.; We used the N-terminal amino acid sequence of dihydrolipoamide dehydrogenase from Haloferax volcanii, to design and synthesize two oligonucleotide probes that were used to identify and clone a 4.3 kilobase pair (kbp) fragment from MboI restriction endonuclease digestion of Hf . volcanii genomic DNA . The nucleotide sequence of a 1.5-kbp region of this clone was determined and this revealed an open reading frame that translated into a protein with good homology to dihydrolipoamide dehydrogenase from other sources . The first 48 amino acids were identical with the N-terminal sequence data obtained from the purified protein . The complete primary structure of the halophilic dihydrolipoamide dehydrogenase was analyzed in terms of its homologies to dihydrolipoamide dehydrogenases from other sources and its molecular adaptations to high intracellular ionic strength. Biochem J, 1992 Jul 1, 285 ( Pt 1), 281 - 6 A serine proteinase of an archaebacterium, Halobacterium mediterranei . A homologue of eubacterial subtilisins; Stepanov VM et al.; A homogeneous serine proteinase secreted by the extreme halophilic bacterium Halobacterium mediterranei 1538 was isolated by affinity chromatography on bacitracin-Sepharose with a yield of 48% (260-fold purification) . The enzyme reveals an optimum for pyroglutamyl-Ala-Ala-Leu p-nitroanilide hydrolysis at pH 8.0-8.5 (Km 0.14 mM; k(cat) . 36.9 s-1) . Its activity increases linearly with NaCl concentration over the range 2-5 M . The substrate specificity of the enzyme is comparable with that of secretory subtilisins, the extent of protein degradation approaching that attained with proteinase K . The enzyme has a molecular mass of 41 kDa and a pI of 7.5 . The N-terminal sequence of H . mediterranei serine proteinase reveals a 50% identity with that of Thermoactinomyces vulgaris serine proteinases, indicating that the enzyme belongs to the subtilisin family . Hence the serine proteinase secreted by the halophilic bacterium should be considered as a functional analogue, and a structural homologue, of eubacterial serine proteinases (subtilisins). Biochem Int, 1992 Jul, 27(2), 275 - 9 Purification and characterization of the HPR protein of Pediococcus halophilus; Arai M et al.; HPr protein, the ptsH gene product, of the phosphoenolpyruvate:sugar phosphotransferase system of Pediococcus halophilus was purified to homogeneity using heat and acid treatments, DEAE-Sepharose CL-6B and hydroxyapatite column chromatographies . The purified protein complemented the HPr activity of the phosphotransferase system in Staphylococcus aureus ptsH mutant cell lysate . The molecular weight was estimated as 6,500 by SDS polyacrylamide gel electrophoresis . The amino acid sequence of the amino-terminal part (1-44) of the native purified protein was highly homologous to those of HPr proteins from gram-positive bacteria . Antiserum raised against the purified HPr protein specifically reacted with the Pediococcus halophilus HPr protein and did not cross-react with Staphylococcus aureus or Escherichia coli HPr proteins. Eur J Biochem, 1992 Jul 1, 207(1), 369 - 76 The catalytic site is located on subunit I of the ATPase from Halobacterium saccharovorum . A direct photoaffinity labeling study; Bonet ML et al.; Nucleotide-binding sites of the ATPase from the halophilic archaebacterium Halobacterium saccharovorum were labeled by ultraviolet irradiation in the presence of {alpha-32P}ATP . A high-affinity site, located on subunit I (98 kDa), was identified as catalytic by the following criteria: ATP bound to subunit I was hydrolyzed and the cross-linked nucleotide was ADP; the specificity for ATP or ADP compared to that of other nucleotides was high; the tightly bound radionucleotide was exchangeable in the presence of excess unlabeled ATP and Mg2+; photolabeling of this site and enzyme inhibition due to tightly bound ADP were both dependent on the presence of Mg2+ and showed identical Kd values; treatment that restored the activity of the ADP-inhibited enzyme also led to the release of the tightly bound nucleotide from subunit I . In addition, a non-catalytic nucleotide-binding site was found, located on subunit II (71 kDa) . This site did not hydrolyze ATP, its occupation was Mg2+ independent and the affinity for ATP and the nucleotide specificity were much lower than that of subunit I . We suspect that this site is nonspecific . These results indicate that H . saccharovorum ATPase is different from F1-ATPases which contain the catalytic site on the second largest subunit, but may be similar to other archaebacterial and vacuolar ATPases. Biochem J, 1992 Jun 15, 284 ( Pt 3), 741 - 7 Novel linear and branched polyamines in the extremely thermophilic eubacteria Thermoleophilum, Bacillus and Hydrogenobacter; Hamana K et al.; Novel tertiary branched tetra-amines, quaternary branched penta-amines, linear penta-amines and linear hexa-amines were distributed as the major polyamines in six obligately extremely thermophilic eubacteria belonging to Thermoleophilum, Bacillus or Hydrogenobacter . The major polyamine of Thermoleophilum album and Thermoleophilum minutum was identified as a quaternary branched penta-amine, 4,4-bis(3-aminopropyl)-1,8-diamino-4-azaoctane (NH2{CH2}3N+({CH2}3NH2)2{CH2}4NH2) by h.p.l.c., t.l.c . and g.c.-m.s . Hydrogenobacter thermophilus and Hydrogenobacter halophilus contained another quaternary branched penta-amine, 4,4-bis(3-aminopropyl)-1,7-diamino-4-azaheptane (NH2{CH2}3N({CH2}3NH2)2{CH2}3NH2) as the major polyamine, and tertiary branched tetra-amines (4-(3-aminopropyl)-1,7-diamino-4-azaheptane (NH2{CH2}3N({CH2}3NH2){CH2}3NH2), 4-(3-aminopropyl)-1,8-diamino-4-azaoctane (NH2{CH2}3N({CH2}3NH2){CH2}4NH2)) and 4,4-bis(3-aminopropyl)-1,8-diamino-4-azaoctane were confirmed as minor components . Bacillus schlegelii contained a branched tetra-amine, 4-(3-aminopropyl)-1,8-diamino-4-azaoctane, a branched penta-amine, 4,4-bis(3-aminopropyl)-1,8-diamino-4-azaoctane, a linear penta-amine, 1,16-diamino-4,8,13-triazahexadecane (NH2{CH2}3NH{CH2}3NH{CH2}4NH{CH2}3NH2) and linear hexa-amine(s), 1,20-diamino-4,8,12,17-tetra-azaeicosane (NH2{CH2}3NH{CH2}3NH{CH2}3NH{CH2}4NH{CH2}3NH2 ) and/or 1,20-diamino-4,8,13,17-tetra-azaeicosane (NH2{CH2}3NH{CH2}3NH{CH2}4NH{CH2}3NH{CH2}3NH2 ). Proc Natl Acad Sci U S A, 1992 Jun 15, 89(12), 5685 - 9 Archaea in coastal marine environments; DeLong EF; Archaea (archaebacteria) are a phenotypically diverse group of microorganisms that share a common evolutionary history . There are four general phenotypic groups of archaea: the methanogens, the extreme halophiles, the sulfate-reducing archaea, and the extreme thermophiles . In the marine environment, archaeal habitats are generally limited to shallow or deep-sea anaerobic sediments (free-living and endosymbiotic methanogens), hot springs or deep-sea hydrothermal vents (methanogens, sulfate reducers, and extreme thermophiles), and highly saline land-locked seas (halophiles) . This report provides evidence for the widespread occurrence of unusual archaea in oxygenated coastal surface waters of North America . Quantitative estimates indicated that up to 2% of the total ribosomal RNA extracted from coastal bacterioplankton assemblages was archaeal . Archaeal small-subunit ribosomal RNA-encoding DNAs (rDNAs) were cloned from mixed bacterioplankton populations collected at geographically distant sampling sites . Phylogenetic and nucleotide signature analyses of these cloned rDNAs revealed the presence of two lineages of archaea, each sharing the diagnostic signatures and structural features previously established for the domain Archaea . Both of these lineages were found in bacterioplankton populations collected off the east and west coasts of North America . The abundance and distribution of these archaea in oxic coastal surface waters suggests that these microorganisms represent undescribed physiological types of archaea, which reside and compete with aerobic, mesophilic eubacteria in marine coastal environments. J Biol Chem, 1992 Jun 15, 267(17), 12123 - 30 The alpha-operon equivalent genome region in the extreme halophilic archaebacterium Haloarcula (Halobacterium) marismortui; Scholzen T et al.; The genome region of the extreme halophilic archaebacterium Haloarcula marismortui equivalent to the alpha-operon of Escherichia coli has been characterized . In H . marismortui, the alpha-operon was found to be located immediately upstream from the S9 gene cluster . The gene order in the halobacterial alpha-operon, given according to the gene products, is tRNA(Ser), HmaS13, HmaS4, HmaS11, and HmaRp alpha . Compared to the corresponding operon from E . coli, the halobacterial gene organization differs in (i) the presence of a gene for tRNA(Ser) (GCU), (ii) the reversed order of the genes for the ribosomal proteins HmaS11 and HmaS4, and (iii) the absence of the gene coding for the ribosomal protein L17 . The primary structure of HmaRp alpha shows high similarity to a subunit of eukaryotic RNA polymerase II (YeaRpB3, HsaRpB33), whereas the similarity to the eubacterial alpha-subunit of RNA polymerase is only weak. J Biochem Biophys Methods, 1992 Jun, 24(3-4), 239 - 47 A novel technique for the preparation of osmotically stabilized and permeabilized cells of extremely halophilic bacteria; D'Souza SE et al.; The cells of Haloferax mediterannei were stabilized by cross-linking with 0.5% glutaraldehyde for 10 min . Such cells were found to be osmotically stable even when suspended in water . The stabilized cells could be permeabilized by treatment with chloroform without leakage of intracellular components . No significant difference in the properties of an intracellular enzyme aldolase was observed, using either cell-free extract or the osmotically stabilized and permeabilized cells . This novel technique can serve as a useful tool for studying in situ regulatory characteristics of intracellular functions in halobacteria and can also help in their re-use under more stabilized conditions for biotechnological applications. J Gen Microbiol, 1992 Jun, 138 ( Pt 6), 1133 - 7 Characterization of a plasmid from moderately halophilic eubacteria; Fernandez-Castillo R et al.; A plasmid has been isolated for the first time from moderately halophilic eubacteria . Halomonas elongata, Halomonas halmophila, Deleya halophila and Vibrio costicola were found to harbour an 11.5 kbp plasmid (pMH1) . The plasmid was isolated and characterized after transformation into Escherichia coli JM101 cells . A restriction map was constructed, and unique restriction sites for EcoRI, EcoRV and ClaI were detected . The occurrence of such a plasmid in the original halophilic strains was confirmed by Southern hybridization . The plasmid carries genetic determinants that mediate resistance to kanamycin, tetracycline, and neomycin . This property, together with its relatively small size, its stability in E . coli cells, and the presence of unique restriction sites, makes pMH1 a good candidate for the development of a cloning vector for moderate halophiles. FEMS Microbiol Lett, 1992 Jun 1, 72(2), 167 - 72 Phylogenetic analysis of the genera Planococcus, Marinococcus and Sporosarcina and their relationships to members of the genus Bacillus; Farrow JA et al.; A phylogenetic analysis based on 16S rRNA was performed on the genera Planococcus, Marinococcus, Sporosarcina and endospore-forming rods . In agreement with earlier 16S rRNA cataloguing data, Planococcus citreus and Sporosarcina ureae clustered with Bacillus pasteurii and other bacilli containing lysine in their cell walls . Sporosarcina halophila was shown to be genetically distinct from S . ureae and formed a loose association with the main Bacillus subtilis grouping . Marinococcus halophilus (formerly Planococcus halophilus) exhibited low levels of relatedness to all reference species examined and formed a distinct line of descent. Nucleic Acids Res, 1992 May 25, 20(10), 2459 - 64 Genomic organization of the halophilic archaeon Haloferax mediterranei: physical map of the chromosome; Lopez-Garcia P et al.; Pulsed field gel electrophoresis (PFG) has been used to study the genomic organization of the halophilic archaeon Haloferax mediterranei . Analysis of the different genomic elements as well as the restriction patterns obtained with several endonucleases revealed that this microorganism has a circular chromosome of 2.9 Mb and, at least, three extrachromosomal elements of 490, 320 and 130 kb respectively . The complete physical map of the chromosome for the endonucleases PacI and BamHI has been constructed, and several BcII, BgIII and DraI restriction fragments have been aligned on these maps . The localization of heterologous and homologous genes on the physical map, including those for rRNA, lay the ground work for the construction of a genetic map. Biochim Biophys Acta, 1992 May 21, 1106(2), 317 - 24 Effect of bacteriorhodopsin on the orientation of the headgroup of 1,2-dimyristoyl-sn-glycero-3-phosphocholine in bilayers: a 31P- and 2H-NMR study; Gale P et al.; Bacteriorhodopsin (BR), purified from the halophilic bacterium, Halobacterium halobium, has been separated from the endogenous purple membrane lipids and reconstituted by detergent dialysis into bilayers of the zwitterionic phospholipid, 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), which was selectively deuterated at the headgroup in the choline alpha- and beta-methylene segments and the choline gamma-methyl groups . Complexes of DMPC/BR contents from 67:1 to 222:1 (mol/mol) were produced under conditions to promote formation of large vesicles (mean diameters 600-700 nm) . The magnitudes of the 2H-NMR quadrupole splittings recorded from the deuterium-labelled headgroup segments, and the 31P-NMR chemical shift anisotropy (CSA) of the phosphate group appeared to vary linearly with the BR content in the complexes over the range of DMPC/BR ratios studied . On increasing the proportion of BR in the DMPC-BR complexes, the 2H-NMR quadrupole splittings measured from the choline gamma-methyl groups and the beta-methylene segments and the 31P-NMR CSA increased in magnitude, while the 2H-NMR quadrupole splitting from the alpha-methylene segment decreased . Such opposing changes in the choline alpha- and beta-methylene segment quadrupole splittings are similar to those reported on increasing the proportion of positively charged amphiphile at the bilayer surface (Seelig et al . (1987) Biochemistry 26, 7535-7541) . It is suggested that BR presents a net positive charge to the phosphocholine headgroups at the protein/lipid interface. Arch Biochem Biophys, 1992 May 15, 295(1), 153 - 60 Purification and properties of an ATPase from Sulfolobus solfataricus; Hochstein LI et al.; A sulfite-activated ATPase isolated from Sulfolobus solfataricus had a relative molecular mass of 370,000 . It was composed of three subunits whose relative molecular masses were 63,000, 48,000, and 24,000 . The enzyme was inhibited by the vacuolar ATPase inhibitors nitrate and N-ethylmaleimide; 4-chloro-7-nitrobenzofurazan (NBD-Cl) was also inhibitory . N-Ethylmaleimide was predominately bound to the largest subunit while NBD-Cl was bound to both subunits . ATPase activity was inhibited by low concentrations of p-chloromercuriphenyl sulfonate and the inhibition was reversed by cysteine which suggested that thiol groups were essential for activity . While the ATPase from S . solfataricus shared several properties with the ATPase from S . acidocaldarius there were significant differences . The latter enzyme was activated by sulfate and chloride and was unaffected by N-ethylmaleimide, whereas the S . solfataricus ATPase was inhibited by these anions as well as N-ethylmaleimide . These differences as well as differences that occur in other vacuolar-like ATPases isolated from the methanogenic and the extremely halophilic bacteria suggest the existence of several types of archaeal ATPases, none of which have been demonstrated to synthesize ATP. J Mol Evol, 1992 May, 34(5), 396 - 405 Early evolutionary relationships among known life forms inferred from elongation factor EF-2/EF-G sequences: phylogenetic coherence and structure of the archaeal domain; Cammarano P et al.; Phylogenies were inferred from both the gene and the protein sequences of the translational elongation factor termed EF-2 (for Archaea and Eukarya) and EF-G (for Bacteria) . All treeing methods used (distance-matrix, maximum likelihood, and parsimony), including evolutionary parsimony, support the archaeal tree and disprove the "eocyte tree" (i.e., the polyphyly and paraphyly of the Archaea) . Distance-matrix trees derived from both the amino acid and the DNA sequence alignments (first and second codon positions) showed the Archaea to be a monophyletic-holophyletic grouping whose deepest bifurcation divides a Sulfolobus branch from a branch comprising Methanococcus, Halobacterium, and Thermoplasma . Bootstrapped distance-matrix treeing confirmed the monophyly-holophyly of Archaea in 100% of the samples and supported the bifurcation of Archaea into a Sulfolobus branch and a methanogen-halophile branch in 97% of the samples . Similar phylogenies were inferred by maximum likelihood and by maximum (protein and DNA) parsimony . DNA parsimony trees essentially identical to those inferred from first and second codon positions were derived from alternative DNA data sets comprising either the first or the second position of each codon . Bootstrapped DNA parsimony supported the monophyly-holophyly of Archaea in 100% of the bootstrap samples and confirmed the division of Archaea into a Sulfolobus branch and a methanogen-halophile branch in 93% of the bootstrap samples . Distance-matrix and maximum likelihood treeing under the constraint that branch lengths must be consistent with a molecular clock placed the root of the universal tree between the Bacteria and the bifurcation of Archaea and Eukarya . The results support the division of Archaea into the kingdoms Crenarchaeota (corresponding to the Sulfolobus branch and Euryarchaeota) . This division was not confirmed by evolutionary parsimony, which identified Halobacterium rather than Sulfolobus as the deepest offspring within the Archaea. Eur J Biochem, 1992 May 1, 205(3), 917 - 25 The primary structure of the antenna polypeptides of Ectothiorhodospira halochloris and Ectothiorhodospira halophila . Four core-type antenna polypeptides in E . halochloris and E . halophila; Wagner-Huber R et al.; Antenna polypeptides from two species of the family Ectothiorhodospiraceae have been investigated . By means of gel filtration and subsequent high-performance liquid chromatography, at least five polypeptides were isolated from each of Ectothiorhodospira halochloris and Ectothiorhodospira halophila . The majority of their primary structures was identified by Edman degradation . Comparison of these polypeptide sequences with the known primary structures of antenna polypeptides from various purple non-sulfur bacteria revealed interesting new aspects with regard to the structure of the core-peripheral antenna system . E . halochloris and E . halophila contain two pairs of alpha- and beta-polypeptides each with typical primary structure elements of core complexes, indicating a modified antenna complex organization. Zhonghua Yi Xue Za Zhi (Taipei), 1992 May, 49(5), 335 - 42 Experience of six patients with Vibrio vulnificus septicemia; Chao CH et al.; Vibrio vulnificus, a halophilic lactose fermenting vibrio, is a virulent pathogen for men and is frequently associated with overwhelming infections of areas other than the gastrointestinal tract . We encountered six cases of Vibrio vulnificus septicemia in Veterans General Hospital-Taipei over the past four years . All were admitted through the emergency room and presented with urgent conditions on arrival . The patients also demonstrated preexisting liver function impairment (either hepatic disease or chronic alcohol consumption) . Five subjects had an apparent history of exposure to marine environments: one fisherman with pre-existing wounds and four others with previous consumption of poorly cooked seafood . Characteristic hemorrhagic bullous lesions were found in 5 cases . In all, 4 patients (67%) died with three of the cases within 24 hours of hospitalization . Misdiagnosis and delayed treatment were the most common causes . In conclusion, when patients present with sepsis and/or characteristic cutaneous lesions, particulously those with underlying liver disease and a history of marine exposure, clinicians should be alerted to this potentially fatal infection and should commence appropriate assessment and treatment immediately. J Biol Chem, 1992 Apr 25, 267(12), 8182 - 5 Drastic differences in glycosylation of related S-layer glycoproteins from moderate and extreme halophiles; Mengele R et al.; The outer surface of the moderate halophilic archaebacterium Haloferax volcanii (formerly named Halobacterium volcanii) is covered with a hexagonally packed surface (S) layer glycoprotein . The polypeptide (794 amino acid residues) contains 7 N-glycosylation sites . Four of these sites were isolated as glycopeptides and the structure of one of the corresponding saccharides was determined . Oligosaccharides consisting of beta-1,4-linked glucose residues are attached to the protein via the linkage unit asparaginyl-glucose . In the related glycoprotein from the extreme halophile Halobacterium halobium, the glucose residues are replaced by sulfated glucuronic acid residues, causing a drastic increase in surface charge density . This is discussed in terms of a recent model explaining the stability of halophilic proteins. Microbiologica, 1992 Apr, 15(2), 149 - 56 Effect of medium salinity on some chemical constituents of two halophilic Bacillus spp . from Saudi Arabia; Salamah AA; The cell envelope amino acids of two moderately halophilic Bacillus isolates (BST and BSF) varied according to medium salinity . Cystine and proline were mostly effected . In both isolates growing in the presence of 6 and 18% NaCl there were more dicarboxylic amino acids than basic amino acids which makes the cell envelope proteins quite acidic . The concentrations of the cell-associated cations (Na+, K+, and Mg2+) were high in both isolates, and varied according to the NaCl concentration . The two isolates contained glucosamine and muramic acid in their cell walls . The amounts of these two sugar derivatives, however, varied with the NaCl concentration . Thin-layer chromatography of phospholipids revealed the presence of cardiolipins, phosphatidylglycerols and phosphatidylethanolamines in the two isolates irrespective of medium salinity . Phosphatidylglycerols and the phosphatidylethanolamines increased on increasing the NaCl concentration of the growth medium . Lysophosphatidylglycerols were detected only in the 6% grown BST cells . Unidentified phospholipids designated X1 (in isolates BSF and BST), X2 (in isolate BST) and X3 (in isolate BSF) were also detected; the concentrations of X1 and X3 were salinity dependent. FEBS Lett, 1992 Mar 30, 300(2), 193 - 6 Mode of sodium ion action on methanogenesis and ATPase of the moderate halophilic methanogenis bacterium Methanohalophilus halophilus; Smigan P et al.; Cells of Methanohalophilus halophilus swelled when exposed to hypotonic solutions of NaCl at pH 7.0 . The swelling of the cells ceased in the presence of Mg2+ . Methane formation by non-growing cells was strongly dependent on the NaCl concentration . Among other monovalent and divalent cations only Li+ and Mg2+ could partly substitute for a specific function of sodium ions . The artificial Na+/H+ antiporter, monensin, exerted a strong inhibitory effect on methane formation from methylamine . The membrane-bound Mg(2+)-stimulated ATPase of these cells was enhanced at low (40 mM) NaCl concentration while higher concentrations of this solute were inhibitory . The results obtained show that sodium ions are a prerequisite for optimal methane formation and ATPase activity in these cells . However, both of these processes required different sodium ion concentrations. J Biol Chem, 1992 Mar 25, 267(9), 5829 - 34 Mevinolin-resistant mutations identify a promoter and the gene for a eukaryote-like 3-hydroxy-3-methylglutaryl-coenzyme A reductase in the archaebacterium Haloferax volcanii; Lam WL et al.; Both eukaryotes and archaebacteria use 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase to synthesize mevalonate, which eukaryotes employ in the production of sterols and archaebacteria need for the isoprenoid side chains of their unique and characteristic lipids . The drug mevinolin inhibits HMG-CoA reductase in eukaryotes and in the halophilic archaebacteria, and we have used a spontaneous mutation to mevinolin resistance in the construction of a selectable shuttle vector for Haloferax volcanii . Sequence analysis shows that this resistance determinant encodes an HMG-CoA reductase very like its eukaryotic homologs, but sharing with the one sequenced eubacterial HMG-CoA reductase (that of Pseudomonas mevalonii) few residues other than those common to all HMG-CoA reductases . Characterization of several spontaneous mevinolin-resistant mutants reveals that they are of two sorts: amplifications of the HMG-CoA reductase gene with varying amounts of flanking sequence, and point mutants upstream of the HMG-CoA reductase coding region . We compared sequence and expression of a mutant gene of the latter class to those of the wild-type gene . The point mutation found affects the TATA box-like "distal promoter element," results (like gene amplification) in resistance through the synthesis of excess gene product, and provides the first true genetic definition of an archaebacterial promoter. J Bacteriol, 1992 Mar, 174(5), 1694 - 7 Genes for tryptophan biosynthesis in the halophilic archaebacterium Haloferax volcanii: the trpDFEG cluster; Lam WL et al.; Tryptophan auxotrophs of the archaebacterium Haloferax volcanii define a cluster of overlapping genes homologous to eubacterial-eukaryotic trpD, -F, -E, and -G, linked in that order and each preceded by a possible ribosome binding site . Residues involved in feedback inhibition of eubacterial anthranilate synthetases are conserved. Antibiot Khimioter, 1992 Mar, 37(3), 10 - 3 {Sensitivity of Vibrio and Aeromonas to antibiotics}; Khaitovich AB et al.; The antibiotic sensitivity of 696 cultures belonging to the family Vibrionaceae (V . cholerae O1, V . cholerae non-O1, V . albensis, V . parahaemolyticus, V . alginolyticus and Aeromonas spp.) was studied and general regularities of the antibiotic sensitivity were shown: a high sensitivity to broad-spectrum antibiotics (tetracycline and chloramphenicol) and a low sensitivity to ++beta lactams (carbenicillin and ampicillin) . The comparative examinations revealed similarity in the antibioticograms of V . cholerae O1 (el Tor++), V . cholerae non-O1 and V . albensis, especially the latter two groups, as well as the tested halophilic Vibrio cultures by the range of the MICs, Mo, Me and the nature of the antibiotic resistance . Cultures of V . cholerae and luminescent Vibrio tended to preserve a high sensitivity . High resistance levels were noted in the halophilic Vibrio and Aeromonas cultures . No significant differences in the sensitivity of the strains of various origin (from man and environmental objects) were detected . However, several more resistant strains were isolated from the environmental objects. Genetics, 1992 Mar, 130(3), 399 - 410 Sequence heterogeneity between the two genes encoding 16S rRNA from the halophilic archaebacterium Haloarcula marismortui; Mylvaganam S et al.; The halophilic archaebacterium, Haloarcula marismortui, contains two nonadjacent ribosomal RNA operons, designated rrnA and rrnB, in its genome . The 16S rRNA genes within these operons are 1472 nucleotides in length and differ by nucleotide substitutions at 74 positions . The substitutions are not uniformly distributed but rather are localized within three domains of 16S rRNA; more than two-thirds of the differences occur within the domain bounded by nucleotides 508 and 823 . This domain is known to be important for P site binding of aminoacylated tRNA and for 30-50S subunit association . Using S1 nuclease protection, it has been shown that the 16S rRNAs transcribed from both operons are equally represented in the functional 70S ribosome population . Comparison of these two H . marismortui sequences to the 16S gene sequences from related halophilic genera suggests that (i) in diverging genera, mutational differences in 16S gene sequences are not clustered but rather are more generally distributed throughout the length of the 16S sequence, and (ii) the rrnB sequence, particularly within the 508-823 domain, is more different from the out group sequences than is the rrnA sequence . Several possible explanations for the evolutionary origin and maintenance of this sequence heterogeneity within 16S rRNA of H . marismortui are discussed. J Bacteriol, 1992 Feb, 174(3), 736 - 42 Molecular cloning and sequencing of the gene for a halophilic alkaline serine protease (halolysin) from an unidentified halophilic archaea strain (172P1) and expression of the gene in Haloferax volcanii; Kamekura M et al.; The gene of a halophilic alkaline serine protease, halolysin, from an unidentified halophilic archaea (archaebacterium) was cloned and its nucleotide sequence was determined . The deduced amino acid sequence showed that halolysin consists of 411 amino acids, with a molecular weight of 41,963 . The highest homology was found with thermitase from Thermoactinomyces vulgaris . Halolysin has a long C-terminal extension of approximately 120 amino acids which has not been found in other extracellular subtilisin type serine proteases . The gene, hly, was expressed in another halophilic archaea, Haloferax volcanii, in a medium containing 18% salts by using a plasmid shuttle vector which has a novobiocin resistance determinant as a selectable marker. J Bacteriol, 1992 Feb, 174(3), 1076 - 80 Transformation of members of the genus Haloarcula with shuttle vectors based on Halobacterium halobium and Haloferax volcanii plasmid replicons; Cline SW et al.; We have stably transformed both Haloarcula vallismortis and Haloarcula hispanica with the halobacterium-Escherichia coli shuttle vectors pWL102 (based on the Haloferax volcanii pHV2 replicon) and pUBP2 (based on the Halobacterium halobium pHH1 replicon) . Haloferax volcanii, Halobacterium halobium, and Haloarcula vailismortis are equally distant from one another and span the phylogenetic depth of the halophilic Archaea; thus, these vectors may be generally useful for the halophiles . Both Haloarcula vallismortis and Haloarcula hispanica exhibit previously unreported complex life cycles and are therefore significant as genetically approachable models of cellular differentiation within the Archaea. J Mol Biol, 1992 Jan 5, 223(1), 361 - 71 Solution studies of elongation factor Tu from the extreme halophile Halobacterium marismortui; Ebel C et al.; The activity, stability and structure in solution of polypeptide elongation factor hEF-Tu from Halobacterium marismortui have been investigated . The protein is stable in aqueous solutions only at high concentrations of NaCl, KCl or ammonium sulphate, whereas it is more active in exchanging GDP at lower salt concentrations . It is more active and stable at lower pH values than is non-halophilic EF-Tu . The structure in solution of the protein was determined by complementary density, ultracentrifugation, dynamic light-scattering and neutron-scattering measurements . The protein has large hydration interactions, similar to those of other halophilic proteins: 0.4 (+/- 0.1) g of water and 0.20 (+/- 0.05) g of KCl associated with 1 g of protein, with a water/KCl mass ratio always remaining close to 2 . The kinetics of inactivation at low salt concentrations showed a stabilizing effect of NaCl when compared to KCl . At low salt concentration, inactivation, protein unfolding and aggregation were strongly correlated . The results suggest that the stabilization model proposed for halophilic malate dehydrogenase by Zaccai et al., involving extensive protein interactions with hydrated salt ions, is also valid for hEF-Tu. Biochem Cell Biol, 1992 Jan, 70(1), 70 - 5 Dihydrolipoamide dehydrogenase from the halophilic archaebacterium Haloferax volcanii: characterization and N-terminal sequence; Vettakkorumakankav N et al.; Dihydrolipoamide dehydrogenase, a flavin disulfide reductase, has been purified and characterized from Haloferax volcanii . The enzyme is a dimer of relative mass 128,000, with an optimal activity at pH 9.0 in 1 M NaCl . Following reduction with its substrate, dihydrolipoamide, the enzyme is inactivated through covalent bond formation with the trivalent arsenical p-aminophenyl arsenoxide . The amino acid composition and the amino acid sequence of the first 49 residues of the N-terminus have been determined. Crit Rev Microbiol, 1992, 18(4), 261 - 83 Polyamines as a chemotaxonomic marker in bacterial systematics; Hamana K et al.; Aliphatic linear polyamines, from diamines to hexaamines, tertiary branched tetraamines, and quaternary branched pentaamines are widely distributed in eubacteria, archaebacteria, and cyanobacteria . Twenty-four linear types and four branched types are acid extractable from bacterial cells and can be chromatographically analyzed and identified . The varieties of polyamines are due to the combination of amino acid decarboxylase activities to form diamines, aminopropyl- and aminobutyl-transfer activities mediated by aminopropyltransferases or Schiff-base complex formation, and hydroxylation activity . The absence or presence of spermidine, norspermidine or homospermidine and the occurrence of 2-hydroxyputrescine and diaminopropane are related to grouping into the alpha, beta, gamma, and delta subclasses within Proteobacteria . Flavobacterium complex and green bacteria contain putrescine and homospermidine . Gram-negative thermophiles contain long linear and branched polyamines; however, their distribution profiles are species specific . Gram-positive eubacteria, which comprise Bacillus cluster, anaerobes, and actinomycetes, ubiquitously contain putrescine and spermidine, while the occurrence of spermine is limited to thermophiles . Archaebacteria are separated into polyamine-absent methanogens and halophiles, homospermidine-dominant methanogens, spermidine-dominant methanogens, and spermidine- and norspermidine-containing thermophiles . Cyanobacteria comprise two types; one group contains homospermidine and the other spermidine . The polyamine distribution pattern can serve as a chemotaxonomic marker in bacterial classification and is associated with bacterial systematics on the level of order, family, or genus. Mol Biol (Mosk), 1992 Jan-Feb, 26(1), 83 - 92 {Immunoelectron-microscopic determination of the localization of tryptophanyl-tRNA synthetase in eubacterial cells of Escherichia coli and Methanococcus halophilus archaebacteria}; Popenko VI et al.; Localization of tryptophanyl-tRNA-synthetase (TRS) was studied in halophilic archaebacterium Methanococcus halophilus and eubacterium E . coli . Ultrathin sections of the cells, fixed with glutaraldehyde and embedded in "Lowicryl K4M" at -35 degrees C, were treated with colloidal gold complexes containing monoclonal antibodies Aml against TRS . The latter bind specifically to TRS isolated both from eucaryotes, archae- and eubacteria . According to the label distribution three zones in M . halophilus and E . coli can be distinguished: (i) about 75% of the whole amount of gold particles are localized in the cytoplasm, the distribution of label being more or less homogeneous; (ii) cytoplasmic regions, adjacent to nucleoid, are intensively labelled (about 20% of the whole amount of label); (iii) very few gold particles (not more than 10% of the whole amount) are present in the nucleoid . The data obtained show, that the distribution of TRS in the nucleoid and cytoplasm of archaebacterium M . halophilus is close to the distribution of TRS, found in E . coli . It supports our previous conclusion that the structural organization of transcription-translation apparatus in methanogen and halophilic archaebacteria is similar to that in eubacteria. Zh Mikrobiol Epidemiol Immunobiol, 1992, (9-10), 5 - 7 {The phages of halophilic vibrios and their use}; Kudriakova TA et al.; The range of the lytic activity of 46 phages of parahemolytic vibrios isolated from lysogenic strains, sea water samples, crabs and mussels has been studied . The phages are represented by virions belonging to morphological groups II, IV, V according to the phage classification currently used in Russia and to different serological groups . No relationship between the sensitivity of vibrio strains to the phages under study and the specificity of serotypes O and K has been established . The preparation of diagnostic phage {see text} suitable for the identification of 82% of strains of parahemolytic vibrios has been proposed. Biochem Soc Symp, 1992, 58, 51 - 72 Archaebacterial lipids: structure, biosynthesis and function; Kates M; The foregoing review of membrane lipids in archaebacteria has revealed a remarkable variety of polar lipids classes, including phospholipids, glycolipids, phosphoglycolipids and sulpholipids, all derived from the one basic core structure, diphytanylglycerol (1) and an equally remarkable set of novel pathways for their biosynthesis . Even with the relatively limited knowledge that we have of the physical properties of these lipids, it is clear that they are well-adapted as membrane components to the particular environmental conditions of the three groups of archaebacteria, extreme halophiles, methanogens, and thermoacidophiles . However, much remains to be learned concerning the precise asymmetric arrangement of the lipids in the membrane bilayers or monolayers, the interaction of the lipids with the membrane proteins, and the function of this membrane lipid asymmetry with respect to ion transport, permeability to nutrients, proton transport and conductance, and energy transduction . Perhaps then these unusual lipids will not appear so strange and our knowledge of them will help us to understand the function of the more familiar lipids in the eubacteria and eukaryotes. Biochem Soc Symp, 1992, 58, 135 - 47 Biotechnological potential of halobacteria; Rodriguez-Valera F; The extremely halophilic archaebacteria (halobacteria) became an early focus of scientific interest owing to their role in salted food deterioration . In more recent times their peculiar physiology involving extreme adaptation to the salt environment and other unique features have allowed the development of other applied interests . Their similarities to eukaryotic cells at the level of cell division justifies their use in the prescreening for anti-cancer drugs, and some of their antigens could be used for cancer diagnosis . Their unique retinal proteins can be used as light-biosensors and the use of the purple membrane (pm) as reversible holographic medium has already been developed . Halobacterial enzymes are an extremely tough raw material for enzyme technology, particularly for applications in which the reaction mixture has very low water activity . Thanks to their peculiar lipids and to the production of polysaccharides by some halobacteria, their cultures could be used for enhanced oil recovery . Some halobacteria are excellent producers of industrially interesting biopolymers . The use of halobacteria as producers of polyhydroxyalkanoates, biological polyesters such as poly-3-hydroxybutyrate, with the properties of biodegradable thermoplastics, is being considered. Biochem Soc Symp, 1992, 58, 113 - 25 Halophilic malate dehydrogenase--a case history of biophysical investigations: ultracentrifugation, light-, X-ray- and neutron scattering; Eisenberg H; Halophilic malate dehydrogenase (hMDH) from Haloarcula marismortui has been isolated, purified and characterized by biochemical and biophysical solution studies . A stabilization mechanism at extremely high concentrations of salt, based on the formation of co-operative hydrate bonds between the protein and hydrated salt ions, was suggested from thermodynamic analysis of native enzyme solutions . Recently the gene coding for hMDH was isolated and sequenced and an active enzyme cloned (F . Cendrin, J . Chroboczek, G . Zaccai, H . Eisenberg and M . Mevarech, unpublished work) . A study of the crystal structure of hMDH in a high-salt physiological medium is in progress (O . Butbul-Dym & J . Sussman, personal communication) . Here we discuss in depth implications of these recent developments on our earlier results. J Biol Chem, 1991 Dec 25, 266(36), 24573 - 9 Halobacterial S9 operon . Three ribosomal protein genes are cotranscribed with genes encoding a tRNA(Leu), the enolase, and a putative membrane protein in the archaebacterium Haloarcula (Halobacterium) marismortui; Kromer WJ et al.; In the eubacterium Escherichia coli the genes for the ribosomal proteins L13 and S9 form an operon consisting of two genes . The corresponding operon of the archaebacterium Haloarcula marismortui (Halobacterium marismortui was recently reassigned to the genus Haloarcula {Oren, A., Ginzburg, M., Ginzburg, B . Z., Hochstein, L . I., and Volcani, B . E . (1990) Int . J . Syst . Bacteriol . 40, 209-210} and is now called Haloarcula marismortui) which is presented here, is much larger encoding three ribosomal proteins (HL29, HmaL13, HmaS9), a tRNA(Leu), the glycolytic enzyme enolase (HmaEno), a putative membrane protein (OrfMSG), and two not yet identified open reading frames (OrfMMV, OrfMNA) . The nucleotide sequence of 3931 base pairs has been established . Northern analysis revealed the existence of a polycistronic mRNA (3.7 kilobases) demonstrating that the transcription of a gene of the glycolytic pathway is coupled to the transcription of ribosomal protein genes . Upstream of the first gene of the operon (tRNA(Leu)) a promoter structure typical for the extreme halophilic archaebacteria was detected and downstream of the last gene (OrfMSG) a terminator structure was present . As shown by S1-nuclease mapping, a tRNA-mRNA transcript as well as the mRNA alone was present in vivo . The transcriptional start point and the tRNA-mRNA cleavage point are shown to be almost identical to the 5' and 3' ends, respectively, of the putative mature tRNA . The C-terminal part of the OrfMSG protein shows a significant similarity to the vertebrate laminin receptor protein. Biochemistry, 1991 Dec 24, 30(51), 11781 - 7 Determination of peptide regions on the surface of the eubacterial and archaebacterial ribosome by limited proteolytic digestion; Kruft V et al.; Limited proteolysis was used in combination with two-dimensional gel electrophoresis, blotting, and amino acid sequence analysis to investigate the surface of intact ribosomal subunits at the peptide and amino acid level . Surface sites of 14 ribosomal proteins from Escherichia coli 50S subunits were determined using proteases with different specificities . To assess the evolutionary conservation of ribosomal topography among eubacteria, large subunits from Bacillus stearothermophilus were also subjected to limited proteolysis . The results obtained indicate a conservation of the three-dimensional ribosomal structure at the peptide level . The data for the eubacterial ribosomes are in full agreement with the model of the 50S protein topography derived from immunological data . Furthermore, peptide surface regions of archaebacterial ribosomes have been investigated . The results presented in this work prove that limited proteolysis can successfully be applied to halophilic and thermophilic ribosomes from archaebacteria. Eur J Biochem, 1991 Dec 18, 202(3), 715 - 28 Protein stability and molecular adaptation to extreme conditions; Jaenicke R; Proteins, due to the delicate balance of stabilizing and destabilizing interactions, are only marginally stable . Adaptation to extreme environments tends to shift the 'mesophilic' characteristics of proteins to the respective extremes of temperature, hydrostatic pressure, pH and salinity, such that, under the mutual physiological conditions, the molecular properties are similar regarding overall topology, flexibility and solvation . Enhanced intrinsic stability requires only minute local structural changes so that general strategies of stabilization cannot be established . Apart from mutative changes of amino-acid sequences, extrinsic factors (or cellular components) may be involved in 'extremophilic adaptation' . The molecular basis of acidophilic, alkalophilic and barophilic adaptation is still obscure . Mechanisms of enhanced thermal stability involve improved packing density, as well as specific local interactions . In halophiles, water and salt binding of the intrinsically stable protein inventory is accomplished by favoring acidic over basic amino acid residues and decreased hydrophobicity . General limits of viability are: (a) the susceptibility of the covalent structure of the polypeptide chain toward hydrolysis or hydrothermal degradation; (b) the competition of extreme solvent parameters with the weak electrostatic and hydrophobic interactions involved in protein stabilization; (c) perturbations of the folding and assembly of proteins; and (d) 'dislocation' of biochemical pathways due to effects of extreme conditions on the intricate network of metabolic reactions. FEBS Lett, 1991 Dec 9, 294(3), 271 - 4 Glycinebetaine enhances and stabilizes the evolution of oxygen and the synthesis of ATP by cyanobacterial thylakoid membranes; Mamedov MD et al.; Glycinebetaine (betaine), an osmoregulant in halophilic plants, stabilized the evolution of oxygen and the synthesis of ATP by thylakoid membranes from the cyanobacterium Synechocystis PCC6803 when it was present during the preparation and incubation of the thylakoid membranes . Moreover, betaine enhanced the evolution of oxygen and the synthesis of ATP when present during assays . When betaine at 1.0 M was present during the preparation of thylakoid membranes and during the measurement of activity, the rate of evolution of oxygen was equivalent to that of intact cells. Enferm Infecc Microbiol Clin, 1991 Dec, 9(10), 630 - 3 {Vibrio alginolyticus and swimmer's otitis externa . 2 cases and review of the literature}; Dronda F et al.; We describe two patients with acute diffuse external otitis (swimmer's otitis) acquired in the Mediterranean shore, with Vibrio alginolyticus recovered from ear fluid . We describe the biochemical profile and sensitivity pattern (MIC) of both strains, comparing it to previously published data . A literature review was also performed, in which we found evidence for increasing concern of V . alginolyticus as an human pathogen . Also there is a need for considering halophilic vibrio as potential pathogens, specially if there is also epidemiologic support. Mol Gen Genet, 1991 Dec, 230(3), 345 - 52 The gene for a halophilic glutamate dehydrogenase: sequence, transcription analysis and phylogenetic implications; Benachenhou N et al.; We have isolated and sequenced the gene for a putative NADP-dependent glutamate dehydrogenase from the extremely halophilic archaebacterium Halobacterium salinarium . This gene is transcribed as a unique RNA molecule of about 1700 nucleotides . The 5' end of the transcript contains characteristic consensus transcription initiation and promoter sequences observed in halophilic archaebacteria . The encoded polypeptide, with a predicted length of 435 amino acids, shows significant overall homology and conservation of functional domains when compared with different eubacterial and eukaryotic glutamate dehydrogenases . Surprisingly, the archaebacterial protein shares a larger number of identical amino acid residues with homologous polypeptides from higher eukaryotes than with those from unicellular eukaryotes and eubacteria. Photochem Photobiol, 1991 Dec, 54(6), 1039 - 45 Australian Halobacteria and their retinal-protein ion pumps; Mukohata Y et al.; Halophiles collected in Western Australia have been found to be examples of extremely halophilic rod-shaped archaebacteria, members of the genus Halobacterium . Most of them contain retinal proteins, and these proteins differ from one another and also from both bacteriorhodopsin (bR) and halorhodopsin {and sensory rhodopsins (sR)} isolated from Halobacterium salinarium (halobium), as revealed by their peptide maps and amino acid sequences . However, these retinal proteins still have the ability to pump protons or chloride ions in the light . These new ion pumps, designated archaerhodopsins (aR) {Mukohata et al . (1988) Biochem . Biophys . Res . Commun . 151, 1339-1345}, are almost identical in terms of their molecular sizes and transient photochemical properties to the ion pumps identified previously . Differences are found in the: (1) apparent extinction coefficient of dark/light-adapted aR-2; (2) titration profiles at acidic pH of the absorption spectra of all aRs; and (3) circular dichroism spectra, which are influenced by the coexistent isoprenoid bacterioruberin . The amino acid sequences of two proton pumps from the Australian halobacteria, namely aR and aR-2, are approximately 90% homologous and both sequences are about 60% homologous with that of bR . Hydropathy plots suggest that these pumps also have a seven-helical structure similar to that of bR . The amino acid residues are highly conserved in the helical regions, in particular in the case of helices C and G (91 and 84%, respectively), among the three proton pumps. J Bacteriol, 1991 Nov, 173(21), 7021 - 3 Use of 23Na nuclear magnetic resonance spectroscopy to determine the true intracellular concentration of free sodium in a halophilic eubacterium; Gilboa H et al.; We present new data obtained by 23Na nuclear magnetic resonance spectroscopy, which can distinguish free intracellular sodium from cell-bound sodium, showing that the intracellular concentration of Na+ the halophilic eubacterium Vibrio costicola is only 5 to 20% of that in the extracellular medium . Previous methods could not distinguish free intracellular Na+ from that bound to cell structures, and it was believed that in halophilic eubacteria the total monovalent cation concentration inside matched that of the NaCl outside . Information obtained by the newer technology raises fundamental questions about the ways in which these organisms and others which live in hypersaline environments function and cope with osmotic stress. Appl Environ Microbiol, 1991 Nov, 57(11), 3367 - 70 Reduction of nitrosubstituted aromatic compounds by the halophilic anaerobic eubacteria Haloanaerobium praevalens and Sporohalobacter marismortui; Oren A et al.; The moderately halophilic, obligately anaerobic eubacteria Haloanaerobium praevalens DSM 2228 and Sporohalobacter marismortui ATCC 35420 are able to reduce a variety of nitrosubstituted aromatic compounds at a high rate to the corresponding amines . Compounds degraded included nitrobenzene, o-nitrophenol, m-nitrophenol, p-nitrophenol, nitroanilines, 2,4-dinitrophenol, and 2,4-dinitroaniline . Most of these compounds, when added at concentrations of 50 to 100 mg/liter, were completely transformed within 24 h, but at the highest concentrations growth rates were somewhat lowered . Growth of H . praevalens in the presence of 14C-labeled p-nitrophenol showed that the compound was not incorporated by the cells or degraded to acid-volatile compounds. J Biol Chem, 1991 Oct 5, 266(28), 18660 - 7 The molecular structure of the high potential iron-sulfur protein isolated from Ectothiorhodospira halophila determined at 2.5-A resolution; Breiter DR et al.; The molecular structure of a high potential iron-sulfur protein (HiPIP) isolated from the purple photosynthetic bacterium, Ectothiorhodospira halophila strain BN9626, has been solved by x-ray diffraction analysis to a nominal resolution of 2.5 A and refined to a crystallographic R value of 18.4% including all measured x-ray data from 30.0- to 2.5-A resolution . Crystals used in the investigation contained two molecules/asymmetric unit and belonged to the space group P21 with unit cell dimensions of a = 60.00 A, b = 31.94 A, c = 40.27 A, and beta = 100.5 degrees . An interpretable electron density map, obtained by combining x-ray data from one isomorphous heavy atom derivative with non-crystallographic symmetry averaging and solvent flattening, clearly showed that this high potential iron-sulfur protein contains 71 amino acid residues, rather than 70 as originally reported . As in other bacterial ferredoxins, the {4Fe-4S} cluster adopts a cubane-like conformation and is ligated to the protein via four cysteinyl sulfur ligands . The overall secondary structure of the E . halophila HiPIP is characterized by a series of Type I and Type II turns allowing the polypeptide chain to wrap around the {4Fe-4S} prosthetic group . The hydrogen bonding pattern around the cluster is nearly identical to that originally observed in the 85-amino acid residue Chromatium vinosum HiPIP and consequently, the 240 mV difference in redox potentials between these two proteins cannot be simply attributed to hydrogen bonding patterns alone. J Bacteriol, 1991 Oct, 173(19), 6101 - 9 Phylogenetic analysis of the spirochetes; Paster BJ et al.; The 16S rRNA sequences were determined for species of Spirochaeta, Treponema, Borrelia, Leptospira, Leptonema, and Serpula, using a modified Sanger method of direct RNA sequencing . Analysis of aligned 16S rRNA sequences indicated that the spirochetes form a coherent taxon composed of six major clusters or groups . The first group, termed the treponemes, was divided into two subgroups . The first treponeme subgroup consisted of Treponema pallidum, Treponema phagedenis, Treponema denticola, a thermophilic spirochete strain, and two species of Spirochaeta, Spirochaeta zuelzerae and Spirochaeta stenostrepta, with an average interspecies similarity of 89.9% . The second treponeme subgroup contained Treponema bryantii, Treponema pectinovorum, Treponema saccharophilum, Treponema succinifaciens, and rumen strain CA, with an average interspecies similarity of 86.2% . The average interspecies similarity between the two treponeme subgroups was 84.2% . The division of the treponemes into two subgroups was verified by single-base signature analysis . The second spirochete group contained Spirochaeta aurantia, Spirochaeta halophila, Spirochaeta bajacaliforniensis, Spirochaeta litoralis, and Spirochaeta isovalerica, with an average similarity of 87.4% . The Spirochaeta group was related to the treponeme group, with an average similarity of 81.9% . The third spirochete group contained borrelias, including Borrelia burgdorferi, Borrelia anserina, Borrelia hermsii, and a rabbit tick strain . The borrelias formed a tight phylogenetic cluster, with average similarity of 97% . THe borrelia group shared a common branch with the Spirochaeta group and was closer to this group than to the treponemes . A single spirochete strain isolated fromt the shew constituted the fourth group . The fifth group was composed of strains of Serpula (Treponema) hyodysenteriae and Serpula (Treponema) innocens . The two species of this group were closely related, with a similarity of greater than 99% . Leptonema illini, Leptospira biflexa, and Leptospira interrogans formed the sixth and most deeply branching group . The average similarity within this group was 83.2% . This study represents the first demonstration that pathogenic and saprophytic Leptospira species are phylogenetically related . The division of the spirochetes into six major phylogenetic clusters was defined also by sequence signature elements . These signature analyses supported the conclusion that the spirochetes represent a monophylectic bacterial phylum. J Bacteriol, 1991 Sep, 173(17), 5352 - 8 Distribution of compatible solutes in the halophilic methanogenic archaebacteria; Lai MC et al.; Accumulation of compatible solutes, by uptake or de novo synthesis, enables bacteria to reduce the difference between osmotic potentials of the cell cytoplasm and the extracellular environment . To examine this process in the halophilic and halotolerant methanogenic archaebacteria, 14 strains were tested for the accumulation of compatible solutes in response to growth in various extracellular concentrations of NaCl . In external NaCl concentrations of 0.7 to 3.4 M, the halophilic methanogens accumulated K+ ion and low-molecular-weight organic compounds . beta-Glutamate was detected in two halotolerant strains that grew below 1.5 M NaCl . Two unusual beta-amino acids, N epsilon-acetyl-beta-lysine and beta-glutamine (3-aminoglutaramic acid), as well as L-alpha-glutamate were compatible solutes among all of these strains . De novo synthesis of glycine betaine was also detected in several strains of moderately and extremely halophilic methanogens . The zwitterionic compounds (beta-glutamine, N epsilon-acetyl-beta-lysine, and glycine betaine) and potassium were the predominant compatible solutes among the moderately and extremely halophilic methanogens . This is the first report of beta-glutamine as a compatible solute and de novo biosynthesis of glycine betaine in the methanogenic archaebacteria. Biochem J, 1991 Aug 15, 278 ( Pt 1), 149 - 54 Purification and characterization of aspartate aminotransferase from the halophile archaebacterium Haloferax mediterranei; Muriana FJ et al.; Aspartate aminotransferase from the archaebacterium Haloferax mediterranei was purified and found to be homogeneous . An average Mr of 66,000 was estimated . The native halophilic transaminase exhibited no maximum absorption at 410 nm, which indicates that the apo form is obtained by our purification procedure, and the molar absorption coefficient at 275 nm in 3.5 M-KCl (pH 7.8) was found to be 78.34 mM-1.cm-1 . Plots of titration data show that 1 mol of halophilic aspartate aminotransferase binds 2 mol of pyridoxal 5'-phosphate . The halophilic transaminase behaved as a dimer with two similar subunits and had a maximum activity in the pH range 7.6-7.9 and at 65 degrees C in 3.5 M-KCl . By differential scanning calorimetry, the denaturation temperature of the halophilic holo- and apo-transaminase was determined to be 78.5 and 68.0 degrees C respectively at 3.3 M-KCl (pH 7.8) . At low salt concentration the halophilic transaminase was inactivated, following first-order kinetics . The Km values for 2-oxoglutarate and L-aspartate, in 3 M-KCl (pH 7.8), were 0.75 mM and 12.6 mM respectively. Appl Environ Microbiol, 1991 Aug, 57(8), 2246 - 50 Production of the siderophore aerobactin by a halophilic pseudomonad; Buyer JS et al.; A bacterial strain, isolated from a cyanobacterial culture, was identified as Pseudomonas sp . strain X40 . Under iron-limiting conditions, the Pseudomonas sp . produced aerobactin, a dihydroxamate siderophore previously found only in the family Enterobacteriaceae . Aerobactin was identified by electrophoretic mobility, spectrophotometric titration, proton nuclear magnetic resonance spectroscopy, mass spectrometry, acid hydrolysis, and biological activity . Aerobactin was used as a siderophore in the Pseudomonas sp . and Escherichia coli . Two iron-repressed outer membrane proteins were observed in the Pseudomonas sp., neither of which had electrophoretic mobility identical to that of the aerobactin outer membrane receptor protein from E . coli . DNA hybridization assays showed no hybridization to the aerobactin genes from the E . coli plasmid pColV, indicating that the genetic determinants for aerobactin production by Pseudomonas strain X40 differ substantially from those found in the archetypic enteric plasmid pColV-K30. Eur J Biochem, 1991 Jun 15, 198(3), 593 - 8 Isolation and structure determination of a novel compatible solute from the moderately halophilic purple sulfur bacterium Ectothiorhodospira marismortui; Galinski EA et al.; The halophilic phototrophic bacterium Ectothiorhodospira marismortui produces three organic osmolytes to counterbalance the osmotic pressure of the surrounding medium: glycine betaine, sucrose, and a novel compound . This new compound, which accounts for approximately 30% of the cells' compatible solutes, was isolated and identified by mass spectrometry and nuclear magnetic resonance . It was characterized as N alpha-carbamoyl-L-glutamine 1-amide, an unusual amino acid derivative with no previous reference in the chemical literature . The relatively high cytoplasmic concentration of this compound (approximately 0.5 M) observed at all growth conditions suggests that it may serve a vital function as an osmoticum and/or protectant for Ectothiorhodospira marismortui in a saline environment. Microbiologia, 1991 Jun, 7(1), 35 - 41 Numerical taxonomy of moderately halophilic gram-positive cocci isolated from the Salar de Atacama (Chile); Valderrama MJ et al.; A taxonomic study has been carried out on 22 strains of moderately halophilic motile cocci isolated from the Salar de Atacama (Chile) . The 112 phenotypic tests were analyzed by numerical taxonomy using SSM coefficient and the unweighted pair group method of association (UPGMA) . At the 67% similarity level, two phenons were obtained: phenon A included 11 strains and phenon B, 11 strains too, whereas the six reference strains did not cluster within these two phenons . These results suggest that moderately halophilic cocci with different phenotypic characteristics from previously described species can be isolated from the hypersaline habitat Salar de Atacama. Eur J Biochem, 1991 May 8, 197(3), 781 - 4 Exonuclease activities associated with DNA polymerases alpha and beta of the archaebacterium Halobacterium halobium; Sorokine I et al.; alpha-like and beta-like DNA polymerases have previously been isolated from a halophilic archaebacterium Halobacterium halobium . In this report, we show that the alpha-like DNA polymerase has an associated 3' to 5'-exonuclease activity which is specific for single-stranded DNA, sensitive to both aphidicolin and N-ethylmaleimide and dependent on high salt concentrations like the polymerase activity . As this DNA polymerase has been shown to contain a primase activity, it may be considered as the equivalent to both eukaryotic DNA polymerases alpha and delta . As shown by glycerol-gradient centrifugation and electrophoresis under denaturing conditions, the beta-like polymerase would appear to have a monomeric structure and comprise of a single 65-kDa polypeptide . This DNA polymerase has both 3' to 5'-exonuclease and 5' to 3'-exonuclease activities which, contrary to polymerase activity, are inhibited by high salt concentrations. Mol Microbiol, 1991 May, 5(5), 1159 - 74 A DNA region of 9 kbp contains all genes necessary for gas vesicle synthesis in halophilic archaebacteria; Horne M et al.; We determined the minimal size of the genomic region necessary for gas vesicle synthesis in halophilic archaebacteria by transformation experiments, comparative DNA sequence analysis and investigation of gas vesicle (Vac) mutants . The comparison of the three genomic regions encoding gas vesicles in Halobacterium halobium (p-vac- and c-vac-region) and Haloferax mediterranei (mc-vac-region) indicates high DNA sequence similarity throughout a contiguous sequence of 9 kbp . In each case, this area encompassed at least 13 open reading frames (ORFs) . Ten of these ORFs (gvpD to gvpM) were located 5' to the vac gene encoding the major gas vesicle protein, but were transcribed from the opposite strand . At least two ORFs (gvpC, and gvpN) were located 3' to each vac gene and transcribed from the same strand as the respective vac gene . In the p-vac-region present on plasmid pHH1 these ORFs were transcribed as at least three units, one transcript encompassing gvpD-gvpE, the second encompassing ORFs gvpF to gvpM, and the third unit comprising the ORFs located 3' to the p-vac gene . In H . halobium Vac mutants copies of the insertion elements ISH2, ISH23, ISH26 or ISH27 were found to be integrated throughout the p-vac-region . The de novo synthesis of gas vesicles was tested by transformation of the Vac-negative species, Haloferax volcanii, with various subfragments of the mc-vac- or p-vac-region cloned into vector plasmids . In contrast to a fragment containing the entire 9 kbp region, none of the subfragments tested was sufficient to promote gas vesicle synthesis . However, gas vesicle synthesis could be restored in each Vac mutant containing an ISH element when the entire transcription unit encompassing the mutated gene on pHH1 was present in the wild-type form on the vector construct. West Afr J Med, 1991 Apr-Jun, 10(2), 175 - 80 Cholera and Vibrio parahaemolyticus diarrhoea endemicity in Calabar, Nigeria; Utsalo SJ et al.; The microbiological and morbidity profiles of acute diarrhoeal episodes were studied in 881 patients seen at the Out-Patients Department of the University of Calabar Teaching Hospital (UCTH), Calabar, between January and December, 1988 . Of a total of 108 (12.3%) culturally confirmed bacterial diarrhoeas, 47 (43.5%) were due to Escherichia coli, 33 (30.6%) to vibrios (Vibrio cholerae-01; classical and E1 Tor biotypes and V . parahaemolyticus), while shigella spp . and salmonella . spp . accounted for 29 (17.7%) and 9 (8.3%) episodes respectively . Twenty (64.5%) of the patients with vibrio diarrhoeas were children less than or equal to 10 years . The only case of diarrhoea-associated death observed, involved an 8-month old infant with kwashiorkor and V . parahaemolyticus infection . Bimodal peaks of cholera episodes occurred during the dry season and appeared to coincide with acute water shortage periods in the municipality . The significance of some prevailing ecological factors in stabilizing a focus of cholera and halophilic vibrio diarrhoea endemicity in this region is discussed. Arch Biochem Biophys, 1991 Apr, 286(1), 111 - 6 The ATP synthase of Halobacterium salinarium (halobium) is an archaebacterial type as revealed from the amino acid sequences of its two major subunits; Ihara K et al.; The head piece of the A-type ATP synthase in an extremely halophilic archaebacterium, namely Halobacterium salinarium (halobium), is composed of two kinds of subunit, alpha and beta, and is associated with ATP-hydrolyzing activity . The genes encoding these subunits with hydrolytic activity have been cloned and sequenced . The putative amino acid sequences of the alpha and beta subunits deduced from the nucleotide sequences of the genomic DNA consist of 585 and 471 residues, respectively . The amino acid sequence of the alpha subunit of the halobacterial ATPase is 63 and 49% identical to the alpha subunits of ATPases from two other archaebacteria, Methanosarcina barkeri and Sulfolobus acidocaldarius, respectively . The sequence of the beta subunit is 66 and 55% identical to the beta subunits from these respective organisms . The homology between the alpha and beta subunits is around 30% . In contrast, the sequences of the halobacterial ATPase is less than 30% identical to F1 ATPase when any combination of subunits is considered . However, they are greater than 50% identical to a eukaryotic vacuolar ATPase when alpha and a, beta and b combinations are considered . These data fully confirm the first demonstration of this kind of relationship which was achieved by immunoblotting with an antibody raised against the halobacterial ATPase . We concluded that the archaebacterial ATP synthase is an A-type and not an F-type ATPase . This classification is also demonstrated by a "rooted" phylogenetic tree where halobacteria locate close to other archaebacteria and eukaryotes and distant from eubacteria. Bol Asoc Med P R, 1991 Apr, 83(4), 154 - 6 Halophilic Vibrio infections: a review; Asenjo CW et al.; Halophilic vibrios are gram-negative curved bacilli that requires high concentrations of salt for survival . They are usually found in marine environments and have a worldwide distribution . Infections caused by these organisms are usually associated with ingestion of raw shell fish or exposure of wounds to sea water . The clinical presentation and severity of this infections is wide ranging . The most common presentation is self-limiting gastroenteritis, but soft tissue infections and septicemia do occur and their morbidity and mortality is high specially in patients with liver disease . Early detection and initiation of treatment with tetracycline is of vital importance in soft tissue infections and septicemia since the progression of the infection may be extremely fast. Biochemistry, 1991 Mar 26, 30(12), 3082 - 8 Wild-type and mutant bacterioopsins D85N, D96N, and R82Q: high-level expression in Escherichia coli; Shand RF et al.; The integral membrane protein bacterioopsin, found in the extremely halophilic archaebacterium Halobacterium halobium, was expressed in Escherichia coli as a fusion protein containing 13 heterologous amino acids at the amino terminus . The expressed protein was localized primarily to the E . coli cytoplasmic membrane (greater than 80%) and had an in vivo half-life of 26 min . The amount of bacterioopsin in E . coli crude lysates was quantitated immunologically from Western blots and was expressed at 10-20-fold higher levels than seen previously (i.e., 17 mg/L; 5.6% of the total protein) . Three distinct forms of the protein were detected immunologically: two of the forms were generated by the removal of either one or four amino acid residues at the amino terminus; the third form remained unaltered. J Bacteriol, 1991 Mar, 173(6), 1938 - 43 Purification and properties of an organophosphorus acid anhydrase from a halophilic bacterial isolate; DeFrank JJ et al.; A moderately halophilic bacterial isolate has been found to possess high levels of enzymatic activity against several highly toxic organophosphorus compounds . The predominant enzyme, designated organophosphorus acid anhydrase 2, has been purified 1,000-fold to homogeneity and characterized . The enzyme is a single polypeptide with a molecular weight of 60,000 . With diisopropylfluorophosphate as a substrate, the enzyme has optimum activity at pH 8.5 and 50 degrees C, and it is stimulated by manganese and cobalt. J Bacteriol, 1991 Feb, 173(3), 955 - 60 Halobacterium halobium strains lysogenic for phage phi H contain a protein resembling coliphage repressors; Ken R et al.; DNA-binding proteins such as bacteriophage repressors belong to the helix-turn-helix family . Ionic interactions drive DNA binding, which means that repressors bind DNA most tightly at low salt concentrations . This raises the question of who gene expression might be regulated in obligate halophiles, which maintain internal salt concentrations of about 5 M . As a model system we have investigated the phage phi H, which infects the archaebacterium Halobacterium halobium . Previous genetic data and transcriptional mapping had suggested a region of the phage genome where a repressor might bind . A modified electrophoretic mobility shift assay was used to identify an activity, present only in lysogens, that specifically binds this region . Methylation interference and DNA sequencing were used to identify four similar binding sites, which are arranged so that two copies of a dimer might bind on one face of the DNA helix . Binding of a protein at these sites could block RNA polymerase from initiating a transcript found only during lytic growth . A nearby divergent promoter produces a lysogen-specific transcript, T6, which encodes a member of the helix-turn-helix family of DNA-binding proteins . By expressing the gene in Escherichia coli, we confirmed that T6 specifies the DNA binding activity detected biochemically . The data show that the basic DNA-binding motif of repressors can be adapted even for the unfavorable conditions of high salt concentration. Biochem J, 1991 Feb 1, 273 ( Pt 3), 739 - 45 Arginine deiminase from Halobacterium salinarium . Purification and properties; Monstadt GM et al.; Arginine deiminase from the extreme halophilic archaebacterium Halobacterium salinarium was purified to homogeneity in a four-step procedure with a 310-fold enrichment . The enzyme consists of two identical subunits of 55 kDa; its native molecular mass is 105 kDa . The pI of 4.7 indicates that acidic nature of the protein, which is evidenced by its amino acid composition, which shows an excess of more than 15% of acidic amino acids . The N-terminal amino acid of the enzyme is lysine . Arginine deiminase from Halobacterium salinarium exhibits its highest catalytic activity in the presence of 3.5 M-NaCl, pH 7.6, and at 40 degrees C . The half-activity constant, Ks, for arginine is 3.1 mM . The enzyme is inhibited by ornithine. Indian J Biochem Biophys, 1991 Feb, 28(1), 65 - 7 Products of non-reductive CO2 assimilation in the halophilic archaebacterium Haloferax mediterranei; Rajagopalan R et al.; The products of CO2 fixation by heterotrophically grown Haloferax mediterranei were analysed . The main 14C-labelled alpha-ketoacid detected following incubation with NaH14CO3 and pyruvate or propionate was pyruvate . In presence of these organic acids and NH4+, 14CO2 was incorporated into glutamic and aspartic acids and alanine. Biochim Biophys Acta, 1991 Jan 30, 1061(2), 235 - 46 The effect of salinity on the phase behaviour of total lipid extracts and binary mixtures of the major phospholipids isolated from a moderately halophilic eubacterium; Sutton GC et al.; The effects of molar NaCl concentrations on the phase behaviour of the total lipid extracts and binary mixtures of the major phospholipids, namely phosphatidylethanolamine (PE) and phosphatidylglycerol (PG), isolated from the moderately halophilic eubacterium, Vibrio costicola, grown in 1 M and 3 M NaCl containing media have been studied using X-ray diffraction and freeze-fracture electron microscopy . The effect of both the PE/PG ratio and alterations in fatty acid composition were examined by using binary mixtures which mimicked the PE/PG ratio found in the native bacterial membranes . We show that the samples exhibited complex phase behaviour, including the formation of non-bilayer phases, which depend upon the salinity of both the bacterial culture medium and the suspending solution . The total lipid from bacteria cultured in 1 M NaCl-containing medium and dispersed in 1 M NaCl exhibited a mixture of L alpha and hexagonal-II phases at the optimum growth temperature of the organism (i.e., 30 degrees C), whereas the same lipid dispersed in 3 M NaCl showed only a hexagonal-II phase down to a temperature of +3 degrees C . The total lipid extracted from 3 M NaCl cultures showed only lamellar phases over the temperature range studied (+50 degrees C to -50 degrees C), but the phase transition temperatures of the various lamellar phases were generally higher when the lipid was dispersed in 3 M compared with 1 M NaCl . The phase behaviour of the binary mixtures was similar but not identical to that of the corresponding total lipid extracts and it is suggested that the minor lipid components (diphosphatidylglycerol, lysophosphatidylethanolamine and lysophosphatidylglycerol) play a part in determining the phase behaviour of the native membranes . These results show that the PE/PG ratio and fatty acid composition of the individual phospholipids, which are normally regulated by Vibrio costicola in vivo in response to culture medium salinity, are both important in maintaining a stable bilayer structure within the membrane. Eur J Biochem, 1991 Jan 30, 195(2), 343 - 50 An unusual class I (Schiff base) fructose-1,6-bisphosphate aldolase from the halophilic archaebacterium Haloarcula vallismortis; Krishnan G et al.; An electrophoretically homogeneous class I (Schiff base) alsolase has been isolated for the first time from the archaebacterial halophile Haloarcula (Halobacterium) vallismortis . The aldolase was characterized with respect to its molecular mass, amino acid composition, salt dependency, immunological cross-reactivity and kinetic properties . The subunit mass of aldolase is 27 kDa, which is much smaller than other class I aldolases . By the gel filtration method, the molecular mass of the halobacterial enzyme was estimated as 280 +/- 10 kDa, suggesting a decameric nature . In contrast to many halobacterial proteins, the H . vallismortis aldolase, though a halophilic enzyme, did not show an excess of acidic residues . Unlike the eukaryotic aldolases, the activity of the halobacterial enzyme was not affected by carboxypeptidase digestion . The general catalytic features of the enzyme were similar to its counterparts from other sources . No antigenic similarity could be detected between the H . vallismortis aldolase and class I aldolase from eubacteria and eukaryotes or class II halobacterial aldolases. J Chromatogr, 1991 Jan 2, 562(1-2), 369 - 76 Fast atom bombardment mass spectrometry as a rapid means of screening mixtures of ether-linked polar lipids from extremely halophilic archaebacteria for the presence of novel chemical structures; Kloppel KD et al.; Fast atom bombardment mass spectrometry was used to analyse intact polar ether lipids present at microgram levels in crude lipid mixtures extracted from Halobacterium halobium, Natronococcus occultus and Halobacterium marismortui . Negative-ion spectra showed the intact deprotonated lipid molecules and in some instances their sodium salts . The simplicity of the mass spectra permits the rapid screening of polar lipid mixtures for the presence of novel lipids . Additional structural information of ions with selected masses was obtained after collisionally induced decomposition. Gene, 1991 Jan 2, 97(1), 87 - 95 A complex family of class-II restriction endonucleases, DsaI-VI, in Dactylococcopsis salina; Laue F et al.; A series of class-II restriction endonucleases (ENases) was discovered in the halophilic, phototrophic, gas-vacuolated cyanobacterium Dactylococcopsis salina sp . nov . The six novel enzymes are characterized by the following recognition sequences and cut positions: 5'-C decreases CRYGG-3' (DsaI); 5'-GG decreases CC-3' (DsaII); 5'-R decreases GATCY-3' (DsaIII); 5'-G decreases GWCC-3' (DsaIV); 5'-decreases CCNGG-3' (DsaV); and 5'-GTMKAC-3' (DsaVI), where W = A or T, M = A or C, K = G or T, and N = A, G, C or T . In addition, traces of further possible activity were detected . DsaI has a novel sequence specificity and DsaV is an isoschizomer of ScrFI, but with a novel cut specificity . A purification procedure was established to separate all six ENases, resulting in their isolation free of contaminating nuclease activities . DsaI cleavage is influenced by N6-methyladenine residues {derived from the Escherichia coli-encoded DNA methyltransferase (MTase) M.Eco damI} within the overlapping sequence, 5'-CCRYMGGATC-3'; DsaV hydrolysis is inhibited by a C-5-methylcytosine residue in its recognition sequence (5'-CMCNGG-3'), generated in some DsaV sites by the E . coli-encoded MTase, M.Eco dcmI. Res Microbiol, 1991 Jan, 142(1), 103 - 7 Effect of external salinity changes on cellular composition of some ions and amino acids in Deleya halophila; del Moral A et al.; Changes in total cellular composition of some ions and amino acids of the moderate halophile Deleya halophila were studied in response to external salinity changes . Among the 14 amino acids investigated, the cellular glycine and aspartic acid content increased with increasing salinity . D . halophila also accumulated Na+ at the highest external salt concentrations. Arch Microbiol, 1991, 155(6), 517 - 20 Release of glucose-mediated catabolite repression due to a defect in the membrane fraction of phosphoenolpyruvate: mannose phosphotransferase system in Pediococcus halophilus; Abe K et al.; A spontaneous mutant 9R-4 resistant to 2-deoxyglucose (2DG) was derived from a wild-type strain Pediococcus halophilus I-13 . Phosphoenolpyruvate (PEP)-dependent glucose-6-phosphate formation by the permeabilized 9R-4 cells was less than 5% of that observed with the parent I-13 . In vitro complementation of PEP-dependent 2DG-6-phosphate formation was assayed with combination of the cytoplasmic and membrane fractions prepared from the I-13 and the mutants (9R-4, and X-160 isolated from nature), which were defective in PEP:mannose phosphotransferase system (man:PTS) . The defects in man:PTS of both the strain 9R-4 and X-160 were restricted to the membrane fraction (e.g . EIIman), not to the cytoplasmic one . Kinetic studies on the glucose transport with intact cells and iodoacetate-treated cells also supported the