| sodium ion-proton antiport in a marine bacterium. | alteromonas haloplanktis ejected protons in response to a brief respiratory pulse; the rate of decay of the resulting ph change was accelerated when na+ was present in the suspension medium. the addition of an anaerobic nacl solution to an essentially na+-free anaerobic bacterial suspension induced the acidification of the suspension medium. these results and others discussed provide substantial evidence for the existence of an na+-h+ antiporter in this organism. | 1978 | 26666 |
| heterogeneity and distribution of lipopolysaccharide in the cell wall of a gram-negative marine bacterium. | lipopolysaccharide (lps) extracted from alteromonas haloplanktis 214, variants 1 and 3, separated into three fractions when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. the fractions appeared in the gels as bands which stained for carbohydrate with the periodate-schiff reagent. variant 1, a smooth variant of the organism, and variant 3, a rough colonial variant, produced identical banding patterns. under similar conditions, lps from neisseria meningitidis sdic, escheri ... | 1978 | 711665 |
| identification and sequence of a na(+)-linked gene from the marine bacterium alteromonas haloplanktis which functionally complements the daga gene of escherichia coli. | a 4.0 kb fragment from a plasmid genomic dna library of the marine bacterium alteromonas haloplanktis atcc 19855 was found in the presence of na+ to complement the daga gene of escherichia coli. we have completely sequenced this fragment and the position of the na(+)-linked d-alanine glycine permease gene (daga) on the fragment has been determined by complementation. the predicted carrier protein consists of 542 amino acid residues (m(r) 58,955). its hydropathy profile suggests it is composed of ... | 1992 | 1447975 |
| [detection of aquatic microorganisms from the black sea--producers of restriction endonucleases]. | 300 clones of microorganisms isolated at different stations and from different depths in the black sea were screened for restriction endonucleases production. the production of restriction endonucleases was found in 17 clones screened. three of them were identified to be alteromonas haloplanktis b1. restriction endonuclease ahab1 is an isoshizomer of sau961. an identified alteromonas haloplanktis clone b8 produces ahab8i restriction endonuclease the prototype to which is kpni. of the clones isol ... | 1990 | 1964718 |
| bisucaberin, a new siderophore, sensitizing tumor cells to macrophage-mediated cytolysis. i. taxonomy of the producing organism, isolation and biological properties. | alteromonas haloplanktis strain sb-1123 isolated from deep-sea mud produced a new siderophore, bisucaberin. bisucaberin rendered tumor cells susceptible to cytolysis mediated by murine peritoneal macrophages which were elicited by proteose peptone and not yet activated by lymphokine. bisucaberin exerted its sensitizing activity by both the preincubation with tumor cells and the addition to co-culture of macrophages and tumor cells. the activity of bisucaberin was specifically inhibited by ferric ... | 1987 | 2962972 |
| expression of genes from the marine bacterium alteromonas haloplanktis 214 in escherichia coli k-12. | dna from the marine bacterium alteromonas haloplanktis 214 was partially digested with sau 3a and inserted into the bam hi site of the cloning vector pbr322. the ligation mixture was used to transform escherichia coli hb101. the gene bank plasmid preparation obtained was used to transform escherichia coli k-12 strain eo2717, an organism auxotrophic for histidine, arginine, adenine, uracil and thiamin. prototrophic transformants for each of the five metabolites were isolated using appropriate min ... | 1985 | 3899044 |
| growth characteristics af low na+ concentration and the stability of the na+ requirement of a marine bacterium. | studies of the marine bacterium alteromonas haloplanktis 214 (formerly referred to as marine pseudomonad b-16) showed that as the na+ concentration in the growth medium decreased from 230 to 34 mm, the lowest concentration permitting growth, the length of the lag period preceding exponential growth increased. once growth had begun, except for a slight reduction in rate of growth at 34 mm na+, the generation time and extent of growth remained essentially constant over the range of na+ concentrati ... | 1981 | 7237281 |
| effect of growth at low na+ concentrations on the capacity of a marine bacterium to establish ion gradients and transport alpha-aminoisobutyric acid. | cells of a histidine-auxotrophic, streptomycin-resistant mutant of marine bacterium alteromonas haloplanktis 214 were grown at or near the lowest concentration of na+ permitting growth (30-33 mm na+). when suspended in solutions containing 10 mmkcl and either 30, 100, or 300 mm nacl, the intracellular to extracellular k+ ratios were similar to those obtained with cells of the parent organism grown at more nearly optimum na+ concentrations, whereas the na+ ratios were somewhat larger. cells of th ... | 1981 | 7237282 |
| sodium ion-substrate symport in a marine bacterium. | anaerobic suspensions of alteromonas haloplanktis accumulated alpha-aminoisobutyric acid, by a sodium-dependent process, in response to an artificially imposed membrane potential in the presence or absence of a transmembrane chemical gradient of sodium. these results suggest that the transport of alpha-aminoisobutyrate by this organism occurs via na+-substrate symport. | 1980 | 7380801 |
| pseudoalteromonas antarctica sp. nov., isolated from an antarctic coastal environment. | the taxonomic characteristics of five bacterial strains which were isolated from antarctic coastal marine environments were studied. these bacteria were psychrotrophic, aerobic, and gram negative with polar flagella. the g + c contents of the dnas of these strains were 41 to 42 mol%. the antarctic strains were phenotypically distinct from the previously described pseudoalteromonas type species. dna-dna hybridization experiments revealed that the new strains were closely related to each other but ... | 1997 | 9103620 |
| genetic diversity of the biofilm covering montacuta ferruginosa (mollusca, bivalvia) as evaluated by denaturing gradient gel electrophoresis analysis and cloning of pcr-amplified gene fragments coding for 16s rrna. | the shell of the bivalve montacuta ferruginosa, a symbiont living in the burrow of an echinoid, is covered with a rust-colored biofilm. this biofilm includes different morphotypes of bacteria that are encrusted with a mineral rich in ferric ion and phosphate. the aim of this research was to determine the genetic diversity and phylogenetic affiliation of the biofilm bacteria. also, the possible roles of the microorganisms in the processes of mineral deposition within the biofilm, as well as their ... | 1998 | 9726898 |
| diversity of free-living and attached bacteria in offshore western mediterranean waters as depicted by analysis of genes encoding 16s rrna. | in a previous study (s. g. acinas, f. rodríguez-valera, and c. pedrós-alió, fems microbiol. ecol. 24:27-40, 1997), community fingerprinting by 16s rdna restriction analysis applied to mediterranean offshore waters showed that the free-living pelagic bacterial community was very different from the bacterial cells aggregated or attached to particles of more than about 8 micrometer. here we have studied both assemblages at three depths (5, 50, and 400 m) by cloning and sequencing the 16s rdna obtai ... | 1999 | 9925576 |
| determination of total protein content of bacterial cells by sypro staining and flow cytometry. | an assay has been developed for measuring protein biomass of marine planktonic bacteria by flow cytometry. the method was calibrated by using five species of bacteria (an arcobacter sp., a cytophaga sp., an oceanospirillum sp., a pseudoalteromonas sp., and a vibrio sp.) recently isolated from seawater samples and grown in culture at different temperatures. the intensity of sypro-protein fluorescence of these bacteria strongly correlated with their total protein content, measured by the bicinchon ... | 1999 | 10388732 |
| marine bacterial isolates display diverse responses to uv-b radiation. | the molecular and biological consequences of uv-b radiation were investigated by studying five species of marine bacteria and one enteric bacterium. laboratory cultures were exposed to an artificial uv-b source and subjected to various post-uv irradiation treatments. significant differences in survival subsequent to uv-b radiation were observed among the isolates, as measured by culturable counts. uv-b-induced dna photodamage was investigated by using a highly specific radioimmunoassay to measur ... | 1999 | 10473381 |
| algicidal effects of a novel marine pseudoalteromonas isolate (class proteobacteria, gamma subdivision) on harmful algal bloom species of the genera chattonella, gymnodinium, and heterosigma. | during a bacterial survey of the huon estuary in southern tasmania, australia, we isolated a yellow-pigmented pseudoalteromonas strain (class proteobacteria, gamma subdivision), designated strain y, that had potent algicidal effects on harmful algal bloom species. this organism was identified by 16s rrna sequencing as a strain with close affinities to pseudoalteromonas peptidysin. this bacterium caused rapid cell lysis and death (within 3 h) of gymnodinoids (including gymnodinium catenatum) and ... | 1998 | 9687434 |
| structure of a highly acidic o-specific polysaccharide of lipopolysaccharide of pseudoalteromonas haloplanktis kmm 223 (44-1) containing l-iduronic acid and d-quinhb4nhb. | an acidic o-specific polysaccharide was obtained by mild acid degradation of the lipopolysaccharide isolated by phenol-water extraction of pseudoalteromonas haloplanktis strain kmm 223 (44-1). l-iduronic acid (idoa) was found to be a component of the polysaccharide and identified by nmr spectroscopy and after carboxyl-reduction followed by acid hydrolysis and acetylation, by glc-ms as 2,3,4-tri-o-acetyl-1,6-anhydroidose. on the basis of 1h and 13c nmr spectroscopic studies, including 1d noe, 2d ... | 1998 | 9675369 |
| effectiveness of sytox green stain for bacterial viability assessment. | the effectiveness of sytox green nucleic acid stain for measuring bacterial viability was tested on starved populations of escherichia coli and salmonella typhimurium. this stain underestimates the fraction of dead cells within starved populations containing cells with damaged nucleic acids or membranes. its application to natural samples should be considered with caution. | 1998 | 9647851 |
| phne and glpt genes enhance utilization of organophosphates in escherichia coli k-12. | wild-type escherichia coli k-12 strain ja221 grows poorly on low concentrations (< or = 1 mm) of diisopropyl fluorophosphate and its hydrolysis product, diisopropyl phosphate (dipp), as sole phosphorus sources. spontaneous organophosphate utilization (opu) mutants were isolated that efficiently utilized these alternate sources of phosphate. a genomic library was constructed from one such opu mutant, and two genes were isolated that conferred the opu phenotype to strain ja221 upon transformation. ... | 1998 | 9647836 |
| crystal structures of the psychrophilic alpha-amylase from alteromonas haloplanctis in its native form and complexed with an inhibitor. | alteromonas haloplanctis is a bacterium that flourishes in antarctic sea-water and it is considered as an extreme psychrophile. we have determined the crystal structures of the alpha-amylase (aha) secreted by this bacterium, in its native state to 2.0 angstroms resolution as well as in complex with tris to 1.85 angstroms resolution. the structure of aha, which is the first experimentally determined three-dimensional structure of a psychrophilic enzyme, resembles those of other known alpha-amylas ... | 1998 | 9541387 |
| expression of psychrophilic genes in mesophilic hosts: assessment of the folding state of a recombinant alpha-amylase. | alpha-amylase from the antarctic psychrophile altermonas haloplanktis is synthesized at 0 +/- 2 degrees c by the wild strain. this heat-labile alpha-amylase folds correctly when overexpressed in escherichia coli, providing the culture temperature is sufficiently low to avoid irreversible denaturation. in the described expression system, a compromise between enzyme stability and e. coli growth rate is reached at 18 degrees c. | 1998 | 9501457 |
| cloning and nucleotide sequence of the gyrb gene of vibrio parahaemolyticus and its application in detection of this pathogen in shrimp. | because biochemical testing and 16s rrna sequence analysis have proven inadequate for the differentiation of vibrio parahaemolyticus from closely related species, we employed the gyrase b gene (gyrb) as a molecular diagnostic probe. the gyrb genes of v. parahaemolyticus and closely related vibrio alginolyticus were cloned and sequenced. oligonucleotide pcr primers were designed for the amplification of a 285-bp fragment from within gyrb specific for v. parahaemolyticus. these primers recognized ... | 1998 | 9464408 |
| cloning, sequences, and characterization of two chitinase genes from the antarctic arthrobacter sp. strain tad20: isolation and partial characterization of the enzymes. | arthrobacter sp. strain tad20, a chitinolytic gram-positive organism, was isolated from the sea bottom along the antarctic ice shell. arthrobacter sp. strain tad20 secretes two major chitinases, chia and chib (archia and archib), in response to chitin induction. a single chromosomal dna fragment containing the genes coding for both chitinases was cloned in escherichia coli. dna sequencing analysis of this fragment revealed two contiguous open reading frames coding for the precursors of archia (8 ... | 2001 | 11160110 |
| nucleotide sequence of a gene encoding an organophosphorus nerve agent degrading enzyme from alteromonas haloplanktis. | organophosphorus acid anhydrolases (opaa) catalyzing the hydrolysis of a variety of toxic organophosphorus cholinesterase inhibitors offer potential for decontamination of g-type nerve agents and pesticides. the gene (opa) encoding an opaa was cloned from the chromosomal dna of alteromonas haloplanktis atcc 23821. the nucleotide sequence of the 1.7 -kb dna fragment contained the opa gene (1.3 kb) and its flanking region. we report structural and functional similarity of opaas from a. haloplankti ... | 1997 | 9079288 |
| phylogenetic diversity of bacterial and archaeal communities in the anoxic zone of the cariaco basin. | microbial community samples were collected from the anoxic zone of the cariaco basin at depths of 320, 500, and 1,310 m on a november 1996 cruise and were used to construct 16s ribosomal dna libraries. of 60 nonchimeric sequences in the 320-m library, 56 belonged to the epsilon subdivision of the proteobacteria (epsilon-proteobacteria) and 53 were closely related to ectosymbionts of rimicaris exoculata and alvinella pompejana, which are referred to here as epsilon symbiont relatives (esr). the 5 ... | 2001 | 11282619 |
| the marine bacterium pseudoalteromonas haloplanktis has a complex genome structure composed of two separate genetic units. | the genome size of pseudoalteromonas haloplanktis, a ubiquitous and easily cultured marine bacterium, was measured as a step toward estimating the genome complexity of marine bacterioplankton. to determine total genome size, we digested p. haloplanktis dna with the restriction endonucleases notl and sfil, separated the fragments using pulsed-field gel electrophoresis (pfge), and summed the sizes of the fragments. the p. haloplanktis genome was 3512 +/- 112 kb by notl digestion and 3468 +/- 54.1 ... | 1996 | 8973910 |
| crystallization and preliminary x-ray diffraction studies of alpha-amylase from the antarctic psychrophile alteromonas haloplanctis a23. | a cold-active alpha-amylase was purified from culture supernatants of the antarctic psychrophile alteromonas haloplanctis a23 grown at 4 degrees c. in order to contribute to the understanding of the molecular basis of cold adaptations, crystallographic studies of this cold-adapted enzyme have been initiated because a three-dimensional structure of a mesophilic counterpart, pig pancreatic alpha-amylase, already exists. alpha-amylase from a. haloplanctis, which shares 53% sequence identity with pi ... | 1996 | 8897615 |
| [structure of the repeating link of the acid polysaccharide of alteromonas haloplanktis kmm 156]. | an acidic capsular and an o-specific polysaccharide were isolated from the marine microorganism alteromonas haloplanktis kmm 156. both polysaccharides have the identical structure and are built up of tetrasaccharide repeating units, containing two residues of l-rhamnose as well as a 2-acetamido-2-deoxy-d-glucose and a 3-o-[(r)-1-carboxyethyl]-d-glucose (glc3lac) residue. on the basis of methylation studies, 1h- and 13c-nmr-spectroscopy including nuclear overhauser effect and two-dimensional hete ... | 1993 | 8489533 |
| growth patterns of two marine isolates: adaptations to substrate patchiness? | during bottle incubations of heterotrophic marine picoplankton, some bacterial groups are conspicuously favored. in an earlier investigation bacteria of the genus pseudoalteromonas rapidly multiplied in substrate-amended north sea water, whereas the densities of oceanospirillum changed little (h. eilers, j. pernthaler, and r. amann, appl. environ. microbiol. 66:4634-4640, 2000). we therefore studied the growth patterns of two isolates affiliating with pseudoalteromonas and oceanospirillum in bat ... | 2001 | 11526008 |
| sodium ion cycle in bacterial pathogens: evidence from cross-genome comparisons. | analysis of the bacterial genome sequences shows that many human and animal pathogens encode primary membrane na+ pumps, na+-transporting dicarboxylate decarboxylases or na+ translocating nadh:ubiquinone oxidoreductase, and a number of na+ -dependent permeases. this indicates that these bacteria can utilize na+ as a coupling ion instead of or in addition to the h+ cycle. this capability to use a na+ cycle might be an important virulence factor for such pathogens as vibrio cholerae, neisseria men ... | 2001 | 11528000 |
| flow cytometric analysis of the cellular dna content of salmonella typhimurium and alteromonas haloplanktis during starvation and recovery in seawater. | flow cytometry was used to investigate the heterogeneity of the dna content of salmonella typhimurium and alteromonas haloplanktis cells that were starved and allowed to recover in seawater. hoechst 33342 (bisbenzimide) was used as a dna-specific dye to discriminate between dna subpopulations. the dna contents of both strains were heterogeneous during starvation. s. typhimurium cells contained one or two genomes, and a. haloplanktis cells contained up to six genomes. s. typhimurium genomes were ... | 1994 | 7811075 |
| in situ biodegradation of poly(3-hydroxybutyrate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in natural waters. | the biodegradation of samples of poly(3-hydroxybutyrate)(p(3hb)), poly(3-hydroxybutyrate-co-10%-3-hydroxyvalerate)(p(3hb-co-10 %-3hv)), and poly 3-hydroxybutyrate-co-20%-3-hydroxyvalerate)(p(3hb-co-20%- 3hv)) was investigated in situ in natural waters. the degradation was studied by decrease in mass, molecular weight, and tensile strength. in two freshwater ponds the polymers were slowly degraded. after half a year of submersion the mass loss was less than 7%. after 358 days in a freshwater cana ... | 1995 | 7606659 |
| diversity and detection of nitrate assimilation genes in marine bacteria. | a pcr approach was used to construct a database of nasa genes (called narb genes in cyanobacteria) and to detect the genetic potential for heterotrophic bacterial nitrate utilization in marine environments. a nasa-specific pcr primer set that could be used to selectively amplify the nasa gene from heterotrophic bacteria was designed. using seawater dna extracts obtained from microbial communities in the south atlantic bight, the barents sea, and the north pacific gyre, we pcr amplified and seque ... | 2001 | 11679368 |
| lipid composition and chemotaxonomy of pseudomonas putrefaciens (alteromonas putrefaciens). | the major polar lipids in cells of pseudomonas putrefaciens ncib 10472 grown on nutrient agar were phosphatidylethanolamine, phoisphatidylglycerol, a glucosyldiacylglycerol, a glucuronosyldiacylglycerol and an ornithine amide lipid. an additional phospholipid, tentatively identified as acyl phosphatidylglycerol or bis-phosphatidic acid, was a trace component of the wall lipids from broth cultures, which lacked the glycolipids and the ornithine amide lipid. the wall lipids from broth cultures of ... | 1980 | 7441198 |
| relationship between ion requirements for respiration and membrane transport in a marine bacterium. | intact cells of the marine bacterium alteromonas haloplanktis 214 oxidized nadh, added to the suspending medium, by a process which was stimulated by na+ or li+ but not k+. toluene-treated cells oxidized nadh at three times the rate of untreated cells by a mechanism activated by na+ but not by li+ or k+. in the latter reaction, k+ spared the requirement for na+. intact cells of a. haloplanktis oxidized ethanol by a mechanism stimulated by either na+ or li+. the uptake of alpha-aminoisobutyric ac ... | 1984 | 6690427 |
| energy coupling to k+ transport in a marine bacterium. | cells of the marine bacterium alteromonas haloplanktis 214 atcc 19855 (previously referred to as marine pseudomonad b-16) were depleted of k+ by washing with 0.1 m mgso4. washing with 0.05 m mgso4 lowered the vmax for k+ transport compared with washing with 0.1 m with 0.05 but did not change the km, while washing with lower concentrations of mgso4 caused loss of ultraviolet-absorbing material from the cells. k+ uptake was a strictly aerobic process and was accompanied by proton release. when an ... | 1980 | 6450627 |
| cloning in escherichia coli k-12 of a na+-dependent transport system from a marine bacterium. | the transport of d-alanine by escherichia coli k-12 neither requires nor is stimulated by na+. the transport of d-alanine by the marine bacterium alteromonas haloplanktis 214 requires na+ specifically. mutants of e. coli which were unable to transport d-alanine were isolated by enrichment for d-cycloserine resistance. one of the mutants was transformed with a gene bank of a. haloplanktis chromosomal dna. two transformants, e. coli rm1(ppm1) and e. coli rm1(ppm2) were able to transport d-alanine ... | 1986 | 3512524 |
| sensitivity of some marine bacteria, a moderate halophile, and escherichia coli to uncouplers at alkaline ph. | the inhibitory effects of uncouplers on amino acid transport into three marine bacteria, vibrio alginolyticus 118, vibrio parahaemolyticus 113, and alteromonas haloplanktis 214, into a moderate halophile, vibrio costicola nrc 37001, and into escherichia coli k-12 were found to vary depending upon the uncoupler tested, its concentration, and the ph. higher concentrations of all of the uncouplers were required to inhibit transport at ph 8.5 than at ph 7.0. the protonophore carbonyl cyanide m-chlor ... | 1988 | 3045092 |
| a monocarboxylate permease of rhizobium leguminosarum is the first member of a new subfamily of transporters. | amino acid transport by rhizobium leguminosarum is dominated by two abc transporters, the general amino acid permease (aap) and the branched-chain amino acid permease (bra). however, mutation of these transporters does not prevent this organism from utilizing alanine for growth. an r. leguminosarum permease (mctp) has been identified which is required for optimal growth on alanine as a sole carbon and nitrogen source. characterization of mctp confirmed that it transports alanine (k(m) = 0.56 mm) ... | 2002 | 12218032 |
| osmotic effects of membrane permeability in a marine bacterium. | when cells of alteromonas haloplanktis 214 (atcc 19855) were preloaded with alpha-[(14)c]aminoisobutyric acid or the k(+) in the cells was labeled with (42)k by incubation in a buffered salt solution containing 0.05 m mgso(4), 0.01 m kcl, and 0.3 m nacl, the cells retained their radioactivity when resuspended in the same salt solution. when nacl was omitted from the solution, 80 to 90% of the radioactivity was lost from the cells. cells suspended at intermediate concentrations of nacl also lost ... | 1978 | 641005 |
| secretion of alpha-amylase from pseudoalteromonas haloplanktis tab23: two different pathways in different hosts. | secretion of cold-adapted alpha-amylase from pseudoalteromonas haloplanktis tab23 was studied in three antarctic bacteria. we demonstrated that the enzyme is specifically secreted in the psychrophilic hosts even in the absence of a protein domain that has been previously reported to be necessary for alpha-amylase secretion in escherichia coli. the occurrence of two different secretion pathways in different hosts is proposed. | 2002 | 12270842 |
| composition of the fractions separated by polyacrylamide gel electrophoresis of the lipopolysaccharide of a marine bacterium. | the sugar composition of lipopolysaccharide (lps) isolated from whole cells of alteromonas haloplanktis 214 (previously referred to as marine pseudomonas b-16, atcc 19855), variant 3, of the lipid a, core, and side-chain fractions derived from it, and of the lps fractions (lps i, ii, and iii) obtained by subjecting it to preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis has been determined. conditions optimum for the release of constituent monosaccharides by hydrolysis were e ... | 1978 | 101510 |
| identification of dna-synthesizing bacterial cells in coastal north sea plankton. | we describe a method for microscopic identification of dna-synthesizing cells in bacterioplankton samples. after incubation with the halogenated thymidine analogue bromodeoxyuridine (brdu), environmental bacteria were identified by fluorescence in situ hybridization (fish) with horseradish peroxidase (hrp)-linked oligonucleotide probes. tyramide signal amplification was used to preserve the fish staining during the subsequent immunocytochemical detection of brdu incorporation. dna-synthesizing c ... | 2002 | 12406771 |
| beta-cyanoalanine production by marine bacteria on cyanide-free medium and its specific inhibitory activity toward cyanobacteria. | in screening the culture broth of marine bacteria collected at yap (micronesia), palau (belau), and okinawa (the southwest islands of japan) for antimicroalgal activity, 37 out of 2,594 bacterial isolates tested were found to produce anticyanobacterial substances against oscillatoria amphibia nies-361. one strain, c-979, identified as a vibrio sp., was selected and cultured in 2.4 liters of marine broth 2216 to identify the bioactive compound produced by the strain. the purified very hydrophilic ... | 2000 | 10653741 |
| cold-adapted alanine dehydrogenases from two antarctic bacterial strains: gene cloning, protein characterization, and comparison with mesophilic and thermophilic counterparts. | the genes encoding nad(+)-dependent alanine dehydrogenases (aladhs) (ec 1.4.1.1) from the antarctic bacterial organisms shewanella sp. strain ac10 (shealadh) and carnobacterium sp. strain st2 (caraladh) were cloned and expressed in escherichia coli. of all of the aladhs that have been sequenced, shealadh exhibited the highest level of sequence similarity to the aladh from the gram-negative bacterium vibrio proteolyticus (vpraladh). caraladh was most similar to aladhs from mesophilic and thermoph ... | 1999 | 10473410 |
| excision of is492 requires flanking target sequences and results in circle formation in pseudoalteromonas atlantica. | the gram-negative marine bacterium pseudoalteromonas atlantica produces extracellular polysaccharide (eps) that is important in biofilm formation by this bacterium. insertion and precise excision of is492 at a locus essential for extracellular polysaccharide production (eps) controls phase variation of eps production in p. atlantica. examination of is492 transposition in p. atlantica by using a pcr-based assay revealed a circular form of is492 that may be an intermediate in transposition or a te ... | 1999 | 10438765 |
| a cold-active glucanase from the ruminal bacterium fibrobacter succinogenes s85. | we previously characterized two endoglucanases, celg and egd, from the mesophilic ruminal anaerobe fibrobacter succinogenes s85. further comparative experiments have shown that celg is a cold-active enzyme whose catalytic properties are superior to those of several other intensively studied cold-active enzymes. it has a lower temperature optimum, of 25 degrees c, and retains about 70% of its maximum activity at 0 degrees c, while egd has a temperature optimum of 35 degrees c and retains only abo ... | 1999 | 10049853 |
| cold-active serine alkaline protease from the psychrotrophic bacterium shewanella strain ac10: gene cloning and enzyme purification and characterization. | the gene encoding serine alkaline protease (sapsh) of the psychrotrophic bacterium shewanella strain ac10 was cloned in escherichia coli. the amino acid sequence deduced from the 2,442-bp nucleotide sequence revealed that the protein was 814 amino acids long and had an estimated molecular weight of 85,113. sapsh exhibited sequence similarities with members of the subtilisin family of proteases, and there was a high level of conservation in the regions around a putative catalytic triad consisting ... | 1999 | 9925590 |
| biochemical characterization of a beta-galactosidase with a low temperature optimum obtained from an antarctic arthrobacter isolate. | a psychrophilic gram-positive isolate was obtained from antarctic dry valley soil. it utilized lactose, had a rod-coccus cycle, and contained lysine as the diamino acid in its cell wall. consistent with these physiological traits, the 16s ribosomal dna sequence showed that it was phylogenetically related to other arthrobacter species. a gene (bgas) encoding a family 2 beta-galactosidase was cloned from this organism into an escherichia coli host. preliminary results showed that the enzyme was co ... | 2003 | 12949099 |
| a dna ligase from the psychrophile pseudoalteromonas haloplanktis gives insights into the adaptation of proteins to low temperatures. | the cloning, overexpression and characterization of a cold-adapted dna ligase from the antarctic sea water bacterium pseudoalteromonas haloplanktis are described. protein sequence analysis revealed that the cold-adapted ph dna ligase shows a significant level of sequence similarity to other nad+-dependent dna ligases and contains several previously described sequence motifs. also, a decreased level of arginine and proline residues in ph dna ligase could be involved in the cold-adaptation strateg ... | 2000 | 10848966 |
| culturability and in situ abundance of pelagic bacteria from the north sea. | the culturability of abundant members of the domain bacteria in north sea bacterioplankton was investigated by a combination of various cultivation strategies and cultivation-independent 16s rrna-based techniques. we retrieved 16s rrna gene (rdna) clones from environmental dnas and determined the in situ abundance of different groups and genera by fluorescence in situ hybridization (fish). a culture collection of 145 strains was established by plating on oligotrophic medium. isolates were screen ... | 2000 | 10877804 |
| influence of growth temperature on lipid and phosphate contents of surface polysaccharides from the antarctic bacterium pseudoalteromonas haloplanktis tac 125. | the chemical structural variations induced by different growth temperatures in the lipooligosaccharide and exopolysaccharide components extracted from the antarctic bacterium pseudoalteromonas haloplanktis tac 125 are described. the increase in phosphorylation with the increase in growth temperature seems to be general, because it happens not only for the lipooligosaccharide but also for the exopolysaccharide. structural variations in the lipid components of lipid a also occur. in addition, free ... | 2004 | 14679221 |
| adaptation to extreme environments: macromolecular dynamics in bacteria compared in vivo by neutron scattering. | mean macromolecular dynamics was quantified in vivo by neutron scattering in psychrophile, mesophile, thermophile and hyperthermophile bacteria. root mean square atomic fluctuation amplitudes determining macromolecular flexibility were found to be similar for each organism at its physiological temperature ( approximately 1 a in the 0.1 ns timescale). effective force constants determining the mean macromolecular resilience were found to increase with physiological temperature from 0.2 n/m for the ... | 2004 | 14710189 |
| adaptation to extreme environments: macromolecular dynamics in bacteria compared in vivo by neutron scattering. | mean macromolecular dynamics was quantified in vivo by neutron scattering in psychrophile, mesophile, thermophile and hyperthermophile bacteria. root mean square atomic fluctuation amplitudes determining macromolecular flexibility were found to be similar for each organism at its physiological temperature ( approximately 1 a in the 0.1 ns timescale). effective force constants determining the mean macromolecular resilience were found to increase with physiological temperature from 0.2 n/m for the ... | 2004 | 14710189 |
| bacterial community structure associated with a dimethylsulfoniopropionate-producing north atlantic algal bloom. | the bacteria associated with oceanic algal blooms are acknowledged to play important roles in carbon, nitrogen, and sulfur cycling, yet little information is available on their identities or phylogenetic affiliations. three culture-independent methods were used to characterize bacteria from a dimethylsulfoniopropionate (dmsp)-producing algal bloom in the north atlantic. group-specific 16s rrna-targeted oligonucleotides, 16s ribosomal dna (rdna) clone libraries, and terminal restriction fragment ... | 2000 | 11010865 |
| cold-adapted beta-galactosidase from the antarctic psychrophile pseudoalteromonas haloplanktis. | the beta-galactosidase from the antarctic gram-negative bacterium pseudoalteromonas haloplanktis tae 79 was purified to homogeneity. the nucleotide sequence and the nh(2)-terminal amino acid sequence of the purified enzyme indicate that the beta-galactosidase subunit is composed of 1,038 amino acids with a calculated m(r) of 118,068. this beta-galactosidase shares structural properties with escherichia coli beta-galactosidase (comparable subunit mass, 51% amino sequence identity, conservation of ... | 2001 | 11282601 |
| cloning of two pectate lyase genes from the marine antarctic bacterium pseudoalteromonas haloplanktis strain ant/505 and characterization of the enzymes. | a marine antarctic psychrotolerant bacterium (strain ant/505), isolated from sea ice-covered surface water from the southern ocean, showed pectinolytic activity on citrus pectin agar. the sequencing of the 16s rrna of isolate ant/505 indicates a taxonomic affiliation to pseudoalteromonas haloplanktis. the supernatant of this strain showed three different pectinolytic activities after growth on citrus pectin. by activity screening of a genomic dna library of isolate ant/505 in escherichia coli, t ... | 2001 | 11302501 |
| bacteria mediate methylation of iodine in marine and terrestrial environments. | methyl iodide (ch(3)i) plays an important role in the natural iodine cycle and participates in atmospheric ozone destruction. however, the main source of this compound in nature is still unclear. here we report that a wide variety of bacteria including terrestrial and marine bacteria are capable of methylating the environmental level of iodide (0.1 microm). of the strains tested, rhizobium sp. strain mrcd 19 was chosen for further analysis, and it was found that the cell extract catalyzed the me ... | 2001 | 11375186 |
| a novel replication element from an antarctic plasmid as a tool for the expression of proteins at low temperature. | genetic manipulation of antarctic bacteria has been very limited so far. this article reports the isolation and molecular characterization of a novel plasmid, pmtbl, from the antarctic gram-negative bacterium pseudoalteromonas haloplanktis tac 125. this genetic element, 4,081 bp long, appeared to be a multicopy cryptic replicon with no detectable transcriptional activity. by an in vivo assay, the pmtbl autonomous replication sequence was functionally limited to an alui plasmid fragment of about ... | 2001 | 11523895 |
| structural investigation on the lipooligosaccharide fraction of psychrophilic pseudoalteromonas haloplanktis tac 125 bacterium. | the core structure of the cell-wall lipooligosaccharide (los) fraction of an antarctic gram-negative bacterium, pseudoalteromonas haloplanktis tac 125 strain, was determined to be deacetylated alditols. these were obtained from native los fraction by o-deacylation, dephosphorylation, reduction and finally n-deacylation. two novel structures were detected, the more highly represented molecule consisting of the following hexasaccharide chain: alpha-d-manpnh(2)-(1-->3)-beta-d-galp-(1-->4)-alpha-l-g ... | 2001 | 11589700 |
| difference in bacterial motion between forward and backward swimming caused by the wall effect. | a bacterial cell that has a single polar flagellum alternately repeats forward swimming, in which the flagellum pushes the cell body, and backward swimming, in which the flagellum pulls the cell body. we have reported that the backward swimming speeds of vibrio alginolyticus are on average greater than the forward swimming speeds. in this study, we quantitatively measured the shape of the trajectory as well as the swimming speed. the trajectory shape in the forward mode was almost straight, wher ... | 2005 | 15695638 |
| the meroperon of a mercury-resistant pseudoalteromonas haloplanktis strain isolated from minamata bay, japan. | a mer operon of mercury-resistant pseudoalteromonas haloplanktis strain m1, isolated from sea water of minamata bay, was cloned and analyzed. the mer genes were located in the chromosome and organized as merr-mert-merp-merc-mera-merd, the same order as that in tn21. however, the orientation of the merr gene is the same as that of other mer genes (opposite direction to tn21), and merr was cotranscribed with other mer genes, a pattern that has not been previously seen with mer determinants from ot ... | 2001 | 11601623 |
| structural basis of alpha-amylase activation by chloride. | to further investigate the mechanism and function of allosteric activation by chloride in some alpha-amylases, the structure of the bacterial alpha-amylase from the psychrophilic micro-organism pseudoalteromonas haloplanktis in complex with nitrate has been solved at 2.1 a degrees, as well as the structure of the mutants lys300gln (2.5 a degrees ) and lys300arg (2.25 a degrees ). nitrate binds strongly to alpha-amylase but is a weak activator. mutation of the critical chloride ligand lys300 into ... | 2002 | 12021442 |
| diversity of thiosulfate-oxidizing bacteria from marine sediments and hydrothermal vents. | species diversity, phylogenetic affiliations, and environmental occurrence patterns of thiosulfate-oxidizing marine bacteria were investigated by using new isolates from serially diluted continental slope and deep-sea abyssal plain sediments collected off the coast of new england and strains cultured previously from galapagos hydrothermal vent samples. the most frequently obtained new isolates, mostly from 10(3)- and 10(4)-fold dilutions of the continental slope sediment, oxidized thiosulfate to ... | 2000 | 10919760 |
| a novel family 8 xylanase, functional and physicochemical characterization. | xylanases are generally classified into glycosyl hydrolase families 10 and 11 and are found to frequently have an inverse relationship between their pi and molecular mass values. however, we have isolated a psychrophilic xylanase that belongs to family 8 and which has both a high pi and high molecular mass. this novel xylanase, isolated from the antarctic bacterium pseudoalteromonas haloplanktis, is not homologous to family 10 or 11 enzymes but has 20-30% identity with family 8 members. nmr anal ... | 2002 | 12089151 |
| aspartate aminotransferase from the antarctic bacterium pseudoalteromonas haloplanktis tac 125. cloning, expression, properties, and molecular modelling. | the gene encoding aspartate aminotransferase from the psychrophilic bacterium pseudoalteromonas haloplanktis tac 125 was cloned, sequenced and overexpressed in escherichia coli. the recombinant protein (phaspat) was characterized both at the structural and functional level in comparison with the e. coli enzyme (ecaspat), which is the most closely related (52% sequence identity) bacterial counterpart. phaspat is rapidly inactivated at 50 degrees c (half-life = 6.8 min), whereas at this temperatur ... | 2000 | 10785402 |
| the alpha-amylase gene amyh of the moderate halophile halomonas meridiana: cloning and molecular characterization. | two types of tn1732-induced mutants defective in extracellular amylase activity were isolated from the moderate halophile halomonas meridiana dsm 5425. type i mutants displayed amylase activity in the periplasm, and were unable to use any of the carbon sources tested, including starch and its hydrolysis product maltose. the type ii mutant was affected in the gene responsible for the synthesis of the extracellular alpha-amylase. this gene (amyh) was isolated by functional complementation of mutan ... | 2000 | 10784044 |
| bisucaberin--a dihydroxamate siderophore isolated from vibrio salmonicida, an important pathogen of farmed atlantic salmon (salmo salar). | a siderophore of the bacterial fish pathogen, vibrio salmonicida, was isolated from low-iron culture supernatant and structurally characterized as bisucaberin by fticr- and fab-ms, nmr and gc-ms analysis of the hydrolysis products. although the cyclic dihydroxamate bisucaberin has previously been isolated from a marine bacterium, alteromonas haloplanktis, its involvement in cold-water vibriosis of atlantic salmon (salmon salar) is novel. bisucaberin production in iron-limited media was highest a ... | 2002 | 12046923 |
| lipid a structure of pseudoalteromonas haloplanktis tac 125: use of electrospray ionization tandem mass spectrometry for the determination of fatty acid distribution. | the use of electrospray ionization (esi) tandem mass spectrometry (ms/ms) for the structural determination of the lipid a components of the psychrophilic bacterium pseudoalteromonas haloplanktis tac 125 is reported. the lipid a contains the classical bisphosphorylated beta-(1' --> 6)-linked d-glucosamine disaccharide with 3-hydroxydodecanoyl residues (12 : 0 (3-oh)) linked both as esters and amides to 2', 3' (distal glucosamine) and 2, 3 positions (proximal glucosamine) of the sugar backbone. th ... | 2002 | 12112753 |
| groel from the psychrophilic bacterium pseudoalteromonas haloplanktis tac 125: molecular characterization and gene cloning. | the heat shock response of the psychrophilic bacterium pseudoalteromonas haloplanktis tac 125 (phtac 125) gives rise to the production of several inducible proteins. among these, the protein corresponding to a 55-kda band on sds-page was purified to homogeneity and identified as a groel-like protein. the gene coding for this protein (phgroel) was cloned and sequenced; the deduced amino acid sequence shows 82% sequence identity to groel from escherichia coli (ecgroel). the orf found in the 5' ups ... | 2003 | 12579376 |
| crystallization and preliminary x-ray analysis of a xylanase from the psychrophile pseudoalteromonas haloplanktis. | the 46 kda xylanase from the antarctic microorganism pseudoalteromonas haloplanktis is an enzyme that efficiently catalyzes reactions at low temperatures. here, the crystallization of both the native protein and the semet-substituted enzyme and data collection from both crystals using synchrotron radiation are described. the native data showed that the crystals diffract to 1.3 a resolution and belong to space group p2(1)2(1)2(1), with unit-cell parameters a = 50.87, b = 90.51, c = 97.23 a. sad d ... | 2002 | 12198313 |
| the ars detoxification system is advantageous but not required for as(v) respiration by the genetically tractable shewanella species strain ana-3. | arsenate [as(v); haso(4)(2-)] respiration by bacteria is poorly understood at the molecular level largely due to a paucity of genetically tractable organisms with this metabolic capability. we report here the isolation of a new as(v)-respiring strain (ana-3) that is phylogenetically related to members of the genus shewanella and that also provides a useful model system with which to explore the molecular basis of as(v) respiration. this gram-negative strain stoichiometrically couples the oxidati ... | 2003 | 12732551 |
| fish tale. | the draft sequence of the genome of the japanese pufferfish has just been announced and the temptation to humor is great. | 2002 | 12225574 |
| bioinformatic analysis of an unusual gene-enzyme relationship in the arginine biosynthetic pathway among marine gamma proteobacteria: implications concerning the formation of n-acetylated intermediates in prokaryotes. | the n-acetylation of l-glutamate is regarded as a universal metabolic strategy to commit glutamate towards arginine biosynthesis. until recently, this reaction was thought to be catalyzed by either of two enzymes: (i) the classical n-acetylglutamate synthase (nags, gene arga) first characterized in escherichia coli and pseudomonas aeruginosa several decades ago and also present in vertebrates, or (ii) the bifunctional version of ornithine acetyltransferase (oat, gene argj) present in bacteria, a ... | 2006 | 16409639 |
| dual effects of an extra disulfide bond on the activity and stability of a cold-adapted alpha-amylase. | chloride-dependent alpha-amylases constitute a well conserved family of enzymes thereby allowing investigation of the characteristics of each member to understand, for example, relevant properties required for environmental adaptation. in this context, we have constructed a double mutant (q58c/a99c) of the cold-active and heat-labile alpha-amylase from the antarctic bacterium pseudoalteromonas haloplanktis, defined on the basis of its strong similarity with the mesophilic enzyme from pig pancrea ... | 2002 | 12324460 |
| structure and membrane affinity of a suite of amphiphilic siderophores produced by a marine bacterium. | iron concentrations in the ocean are low enough to limit the growth of marine microorganisms, which raises questions about the molecular mechanisms these organisms use to acquire iron. marine bacteria have been shown to produce siderophores to facilitate iron(iii) uptake. we describe the structures of a suite of amphiphilic siderophores, named the amphibactins, which are produced by a nearshore isolate, gamma proteobacterium, vibrio sp. r-10. each amphibactin has the same tris-hydroxamate-contai ... | 2003 | 12651947 |
| mage: a microbial genome annotation system supported by synteny results. | magnifying genomes (mage) is a microbial genome annotation system based on a relational database containing information on bacterial genomes, as well as a web interface to achieve genome annotation projects. our system allows one to initiate the annotation of a genome at the early stage of the finishing phase. mage's main features are (i) integration of annotation data from bacterial genomes enhanced by a gene coding re-annotation process using accurate gene models, (ii) integration of results o ... | 2006 | 16407324 |
| expression, purification, crystallization and preliminary x-ray crystallographic studies of a psychrophilic cellulase from pseudoalteromonas haloplanktis. | the antarctic psychrophile pseudoalteromonas haloplanktis produces a cold-active cellulase. to date, a three-dimensional structure of a psychrophilic cellulase has been lacking. crystallographic studies of this cold-adapted enzyme have therefore been initiated in order to contribute to the understanding of the molecular basis of the cold adaptation and the high catalytic efficiency of the enzyme at low and moderate temperatures. the catalytic core domain of the psychrophilic cellulase celg from ... | 2003 | 12832777 |
| secretion of psychrophilic alpha-amylase deletion mutants in pseudoalteromonas haloplanktis tac125. | the nature and location of structural features responsible for the secretion of a cold-adapted alpha-amylase in the antarctic marine bacterium pseudoalteromonas haloplanktis tac125 was studied by deletion mutagenesis of the wild-type enzyme and of chimerical proteins derived from the fusion of the alpha-amylase with a reporter enzyme. domain c of the psychrophilic alpha-amylase contains secretion features involved in extracellular targeting. | 2006 | 16630257 |
| determination of phosphorylation sites in lipooligosaccharides from pseudoalteromonas haloplanktis tac 125 grown at 15 degrees c and 25 degrees c by nano-electrospray ionization quadrupole time-of-flight tandem mass spectrometry. | lipooligosaccharides (loss) are macromolecules present on the external cellular membrane of gram-negative bacteria, structurally made of two distinct regions, lipid a and core. by varying their growth temperature, bacteria such as psychrophiles change the phosphorylation distribution of the loss produced. the level of phosphorylation and the phosphate group positions in loss produced by the extremophile psychrophilic bacterium pseudoalteromonas haloplanktis tac 125, grown at 15 degrees c and 25 ... | 2003 | 14515321 |
| carriage of potentially fish-pathogenic bacteria in sparus aurata cultured in mediterranean fish farms. | a bacteriological survey of gilthead sea bream sparus aurata from different fish farms and culture systems on the spanish mediterranean coast was conducted. three different studies were performed. study a included hatchery-reared larvae; study b, periodic examination of randomly sampled growing fish; and study c, growing fish sampled only during mortality/morbidity events. in studies b and c, sea cages, earth ponds and indoor tanks were surveyed, and in both cases diseased (showing clinical sign ... | 2003 | 12747637 |
| promoters from a cold-adapted bacterium: definition of a consensus motif and molecular characterization of up regulative elements. | although low-temperature tolerant micro-organisms were discovered long ago, limited information is still available on the transcription machinery in cold-adapted bacteria. this knowledge represents a necessary background for the investigation of the adaptation of gene-expression mechanisms at low temperatures. the recent development of a shuttle genetic system for the transformation of the cold-adapted gram-negative bacterium pseudoalteromonas haloplanktis strain tac125 has made possible the iso ... | 2004 | 15064979 |
| antibiotic production by a roseobacter clade-affiliated species from the german wadden sea and its antagonistic effects on indigenous isolates. | a strain affiliated with the roseobacter clade and producing a new antibiotic named tropodithietic acid (l. liang, ph.d. thesis, university of göttingen, göttingen, germany, 2003) was isolated from the german wadden sea. the compound showed strong inhibiting properties with respect to marine bacteria of various taxa and marine algae. antibiotic production was found to occur during the complete growth phase. strain mutants without antagonistic properties appeared several times spontaneously. | 2004 | 15066861 |
| psychrophilic superoxide dismutase from pseudoalteromonas haloplanktis: biochemical characterization and identification of a highly reactive cysteine residue. | a psychrophilic superoxide dismutase (sod) has been characterized from the antarctic eubacterium pseudoalteromonas haloplanktis (ph). phsod is a homodimeric iron-containing enzyme and displays a high specific activity, even at low temperature. the enzyme is inhibited by sodium azide and inactivated by hydrogen peroxide; it is also very sensitive to peroxynitrite, a physiological inactivator of the human mitochondrial mn-sod. even though phsod is isolated from a cold-adapted micro-organism, its h ... | 2006 | 16713057 |
| kinetic and structural optimization to catalysis at low temperatures in a psychrophilic cellulase from the antarctic bacterium pseudoalteromonas haloplanktis. | the cold-adapted cellulase celg has been purified from the culture supernatant of the antarctic bacterium pseudoalteromonas haloplanktis and the gene coding for this enzyme has been cloned, sequenced and expressed in escherichia coli. this cellulase is composed of three structurally and functionally distinct regions: an n-terminal catalytic domain belonging to glycosidase family 5 and a c-terminal cellulose-binding domain belonging to carbohydrate-binding module family 5. the linker of 107 resid ... | 2004 | 15287848 |
| characterization of outer membrane vesicles released by the psychrotolerant bacterium pseudoalteromonas antarctica nf3. | pseudoalteromonas antarctica nf3 is an antarctic psychrotolerant gram-negative bacterium that accumulates large amounts of an extracellular polymeric substance (eps) with high protein content. transmission electron microscopy analysis after high-pressure freezing and freeze substitution (hpf-fs) shows that the eps is composed of a capsular polymer and large numbers of outer membrane vesicles (omvs). these vesicles are bilayered structures and predominantly spherical in shape, with an average dia ... | 2006 | 16913913 |
| expression of a temperature-sensitive esterase in a novel chaperone-based escherichia coli strain. | a new principle for expression of heat-sensitive recombinant proteins in escherichia coli at temperatures close to 4 degrees c was experimentally evaluated. this principle was based on simultaneous expression of the target protein with chaperones (cpn60 and cpn10) from a psychrophilic bacterium, oleispira antarctica rb8(t), that allow e. coli to grow at high rates at 4 degrees c (maximum growth rate, 0.28 h(-1)). the expression of a temperature-sensitive esterase in this host at 4 to 10 degrees ... | 2004 | 15294778 |
| prospecting for novel biocatalysts in a soil metagenome. | the metagenomes of complex microbial communities are rich sources of novel biocatalysts. we exploited the metagenome of a mixed microbial population for isolation of more than 15 different genes encoding novel biocatalysts by using a combined cultivation and direct cloning strategy. a 16s rrna sequence analysis revealed the presence of hitherto uncultured microbes closely related to the genera pseudomonas, agrobacterium, xanthomonas, microbulbifer, and janthinobacterium. total genomic dna from t ... | 2003 | 14532085 |
| elongation factor ts from the antarctic eubacterium pseudoalteromonas haloplanktis tac 125: biochemical characterization and cloning of the encoding gene. | the elongation factor ts was isolated from the psychrophilic antarctic eubacterium pseudoalteromonas haloplanktis tac 125 strain (phef-ts), and its functional properties were studied. at 0 degrees c phef-ts enhanced the [(3)h]gdp/gdp exchange rate on the preformed phef-tu.[(3)h]gdp complex by 2 orders of magnitude even at very low tu:ts ratio, by lowering the energy of activation of the exchange reaction. phef-ts is a monomeric protein, and in solution it forms a stable dimeric complex with phef ... | 2004 | 15544346 |
| structure of a full length psychrophilic cellulase from pseudoalteromonas haloplanktis revealed by x-ray diffraction and small angle x-ray scattering. | pseudoalteromonas haloplanktis is a psychrophilic gram-negative bacterium isolated in antarctica, that lives on organic remains of algae. this bacterium converts the cellulose, highly constitutive of algae, into an immediate nutritive form by biodegrading this biopolymer. to understand the mechanisms of cold adaptation of its enzymatic components, we studied the structural properties of an endoglucanase, cel5g, by complementary methods, x-ray crystallography and small angle x-ray scattering. usi ... | 2005 | 15854656 |
| [characterization and gene cloning of the endoglucanase from pseudoalteromonas sp. dy3 strain]. | a bacteria strain dy3 with high endoglucanse activity was isolated from deep sea sediment sample es0109. the 16s rdna sequence of dy3 exhibits identity of 99% with those of the same genus bacteria pseudoalteromonas citrea and pseudoalteromonas elyakovii . the celx gene of dy3 obtained by pcr method is 1479bp in length and encodes a protein of 492 amino acids. the protein encoded by celx gene exhibits 95% sequence identity with endoglucanase celg from pseudoalteromonas haloplanktis. there are two ... | 2004 | 15969114 |
| the precursor of a psychrophilic alpha-amylase: structural characterization and insights into cold adaptation. | the alpha-amylase precursor from the bacterium pseudoalteromonas haloplanktis possesses a propeptide at the c-terminus possibly responsible for outer membrane translocation. unlike the predicted beta-barrel of autotransporters, this c-terminal propeptide displays a noticeable alpha-helix content. it is connected to the enzyme by a disordered linker and has no significant interaction with the catalytic domain. the microcalorimetric pattern of the precursor also demonstrates that the stability of ... | 2003 | 12878029 |
| rapid, accurate, computational discovery of rho-independent transcription terminators illuminates their relationship to dna uptake. | in many prokaryotes, transcription of dna to rna is terminated by a thymine-rich stretch of dna following a hairpin loop. detecting such rho-independent transcription terminators can shed light on the organization of bacterial genomes and can improve genome annotation. previous computational methods to predict rho-independent terminators have been slow or limited in the organisms they consider. | 2007 | 17313685 |
| surprising arginine biosynthesis: a reappraisal of the enzymology and evolution of the pathway in microorganisms. | major aspects of the pathway of de novo arginine biosynthesis via acetylated intermediates in microorganisms must be revised in light of recent enzymatic and genomic investigations. the enzyme n-acetylglutamate synthase (nags), which used to be considered responsible for the first committed step of the pathway, is present in a limited number of bacterial phyla only and is absent from archaea. in many bacteria, shorter proteins related to the gcn5-related n-acetyltransferase family appear to acet ... | 2007 | 17347518 |
| the capsule polysaccharide structure and biogenesis for non-o1 vibrio cholerae nrt36s: genes are embedded in the lps region. | in v. cholerae, the biogenesis of capsule polysaccharide is poorly understood. the elucidation of capsule structure and biogenesis is critical to understanding the evolution of surface polysaccharide and the internal relationship between the capsule and lps in this species. v. cholerae serogroup o31 nrt36s, a human pathogen that produces a heat-stable enterotoxin (nag-st), is encapsulated. here, we report the covalent structure and studies of the biogenesis of the capsule in v. cholerae nrt36s. | 2007 | 17362509 |
| a tale of two oxidation states: bacterial colonization of arsenic-rich environments. | microbial biotransformations have a major impact on contamination by toxic elements, which threatens public health in developing and industrial countries. finding a means of preserving natural environments-including ground and surface waters-from arsenic constitutes a major challenge facing modern society. although this metalloid is ubiquitous on earth, thus far no bacterium thriving in arsenic-contaminated environments has been fully characterized. in-depth exploration of the genome of the beta ... | 2007 | 17432936 |
| [elucidation of structure of lipid a from the marine gram-negative bacterium pseudoalteromonas haloplanktis atcc 14393t]. | the chemical structure of lipid a from the marine gamma-proteobacterium pseudoalteromonas haloplanktis atcc 14393t, a main product of lipopolysaccharide hydrolysis (1% acoh), was determined using chemical methods and nmr spectroscopy. the lipid a was shown to be beta-1,6-glucosaminobiose 1,4'-diphosphate acylated with two (r)-3-hydroxyalkanoic acid residues at c3 and c3' and amidated with one (r)-3-hydroxydodecanoyl and one (r)-3-dodecanoyloxydodecanoyl residue at n2 and n2', respectively. | 2004 | 15469016 |
| exocellular peptides from antarctic psychrophile pseudoalteromonas haloplanktis. | a novel diketopiperazine, named cyclo-(d-pipecolinyl-l-isoleucine) (dkp 1), and 7 known diketopiperazines were isolated from the cell-free culture supernatant of the antarctic psychrophilic bacterium pseudoalteromonas haloplanktis tac125. two diketopiperazines containing pipecolinyl moiety were isolated for the first time from a natural source. two new linear peptides, stable to bacterial proteolytic enzymes, were also characterized. the structures of the isolated compounds were elucidated by me ... | 2005 | 15988629 |
| ecological genomics of marine roseobacters. | bacterioplankton of the marine roseobacter clade have genomes that reflect a dynamic environment and diverse interactions with marine plankton. comparative genome sequence analysis of three cultured representatives suggests that cellular requirements for nitrogen are largely provided by regenerated ammonium and organic compounds (polyamines, allophanate, and urea), while typical sources of carbon include amino acids, glyoxylate, and aromatic metabolites. an unexpectedly large number of genes are ... | 2007 | 17526795 |
| coping with cold: the genome of the versatile marine antarctica bacterium pseudoalteromonas haloplanktis tac125. | a considerable fraction of life develops in the sea at temperatures lower than 15 degrees c. little is known about the adaptive features selected under those conditions. we present the analysis of the genome sequence of the fast growing antarctica bacterium pseudoalteromonas haloplanktis tac125. we find that it copes with the increased solubility of oxygen at low temperature by multiplying dioxygen scavenging while deleting whole pathways producing reactive oxygen species. dioxygen-consuming lip ... | 2005 | 16169927 |
| the psychrophilic bacterium pseudoalteromonas halosplanktis tac125 possesses a gene coding for a cold-adapted feruloyl esterase activity that shares homology with esterase enzymes from gamma-proteobacteria and yeast. | the complete genome of the psychrophilic bacteria pseudoalteromonas haloplanktis tac 125, recently published, owns a gene coding for a putative esterase activity corresponding to the orf pshaa1385, also classified in the carbohydrate active enzymes database (cazy) belonging to family 1 of carbohydrate esterase proteins. this orf is 843 bp in length and codes for a protein of 280 amino acid residues. in this study we characterized and cloned the pshaa1385 gene in escherichia coli. we also charact ... | 2007 | 17543477 |