| identification and characterization of a putative transcriptional regulator controlling the expression of fouling inhibitors in pseudoalteromonas tunicata. | the dark green pigmented marine bacterium pseudoalteromonas tunicata colonizes living surfaces and produces a range of extracellular compounds that inhibit common fouling organisms, including marine invertebrate larvae, algae, bacteria, and fungi. we have observed a positive correlation between the antifouling activity of p. tunicata strain d2 and the expression of pigmentation. to address the hypothesis that pigmentation and antifouling may be jointly regulated in this organism and to begin to ... | 2002 | 11772647 |
| biofilm development and cell death in the marine bacterium pseudoalteromonas tunicata. | the newly described green-pigmented bacterium pseudoalteromonas tunicata (d2) produces target-specific inhibitory compounds against bacteria, algae, fungi, and invertebrate larvae and is frequently found in association with living surfaces in the marine environment. as part of our studies on the ecology of p. tunicata and its interaction with marine surfaces, we examined the ability of p. tunicata to form biofilms under continuous culture conditions within the laboratory. p. tunicata biofilms ex ... | 2004 | 15184116 |
| competitive interactions in mixed-species biofilms containing the marine bacterium pseudoalteromonas tunicata. | pseudoalteromonas tunicata is a biofilm-forming marine bacterium that is often found in association with the surface of eukaryotic organisms. it produces a range of extracellular inhibitory compounds, including an antibacterial protein (alpp) thought to be beneficial for p. tunicata during competition for space and nutrients on surfaces. as part of our studies on the interactions between p. tunicata and the epiphytic bacterial community on the marine plant ulva lactuca, we investigated the hypot ... | 2005 | 15811995 |
| unravelling the role of the toxr-like transcriptional regulator wmpr in the marine antifouling bacterium pseudoalteromonas tunicata. | the dark-green-pigmented marine bacterium pseudoalteromonas tunicata produces several target-specific compounds that act against a range of common fouling organisms, including bacteria, fungi, protozoa, invertebrate larvae and algal spores. the toxr-like regulator wmpr has previously been shown to regulate expression of bioactive compounds, type iv pili and biofilm formation phenotypes which all appear at the onset of stationary phase. in this study a comparison of survival under starvation or s ... | 2006 | 16622055 |
| enhanced biofilm formation and increased resistance to antimicrobial agents and bacterial invasion are caused by synergistic interactions in multispecies biofilms. | most biofilms in their natural environments are likely to consist of consortia of species that influence each other in synergistic and antagonistic manners. however, few reports specifically address interactions within multispecies biofilms. in this study, 17 epiphytic bacterial strains, isolated from the surface of the marine alga ulva australis, were screened for synergistic interactions within biofilms when present together in different combinations. four isolates, microbacterium phyllosphaer ... | 2006 | 16751497 |
| ecological advantages of autolysis during the development and dispersal of pseudoalteromonas tunicata biofilms. | in the ubiquitous marine bacterium pseudoalteromonas tunicata, subpopulations of cells are killed by the production of an autocidal protein, alpp, during biofilm development. our data demonstrate an involvement of this process in two parameters, dispersal and phenotypic diversification, which are of importance for the ecology of this organism and for its survival within the environment. cell death in p. tunicata wild-type biofilms led to a major reproducible dispersal event after 192 h of biofil ... | 2006 | 16885293 |
| inhibition of fungal colonization by pseudoalteromonas tunicata provides a competitive advantage during surface colonization. | the marine epiphytic bacterium pseudoalteromonas tunicata produces a range of extracellular secondary metabolites that inhibit an array of common fouling organisms, including fungi. in this study, we test the hypothesis that the ability to inhibit fungi provides p. tunicata with an advantage during colonization of a surface. studies on a transposon-generated antifungal-deficient mutant of p. tunicata, fm3, indicated that a long-chain fatty acid-coenzyme a ligase is involved in the production of ... | 2006 | 16957232 |
| a mannose-sensitive haemagglutinin (msha)-like pilus promotes attachment of pseudoalteromonas tunicata cells to the surface of the green alga ulva australis. | this study demonstrates that attachment of the marine bacterium pseudoalteromonas tunicata to the cellulose-containing surface of the green alga ulva australis is mediated by a mannose-sensitive haemagglutinin (msha-like) pilus. we have identified an msha pilus biogenesis gene locus in p. tunicata, termed msh/1/2jklmnegfbacdopq, which shows significant homology, with respect to its genetic characteristics and organization, to the msha pilus biogenesis gene locus of vibrio cholerae. electron micr ... | 2006 | 17005969 |
| the use of functional genomics for the identification of a gene cluster encoding for the biosynthesis of an antifungal tambjamine in the marine bacterium pseudoalteromonas tunicata. | a large insert library was created in escherichia coli from the dna of the surface-associated marine bacterium pseudoalteromonas tunicata. screening of the library for antifungal activity resulted in the detection and identification of a large gene cluster encoding for the biosynthesis of an antifungal tambjamine. a biosynthetic pathway has been proposed based on analysis and annotation of the gene cluster. | 2007 | 17298379 |
| molecular investigation of the distribution, abundance and diversity of the genus pseudoalteromonas in marine samples. | the genus pseudoalteromonas has attracted interest because it has frequently been found in association with eukaryotic hosts, and because many pseudoalteromonas species produce biologically active compounds. one distinct group of pseudoalteromonas species is the antifouling subgroup containing pseudoalteromonas tunicata and ps. ulvae, which both produce extracellular compounds that inhibit growth and colonization by different marine organisms. pcr primers targeting the 16s rrna gene of the genus ... | 2007 | 17573938 |
| total syntheses of tambjamines c, e, f, g, h, i and j, be-18591, and a related alkaloid from the marine bacterium pseudoalteromonas tunicata. | the acetate salts of tambjamines c, e, and f (2-4, respectively), as well as those of the related alkaloids be-18591 (5) and 6, have been prepared by treatment of bipyrrole aldehyde 16 with the relevant amine in the presence of acetic acid. the 5'-bromo-analogue, 30, of compound 16 has also been prepared and used to obtain the acetate salts of tambjamines g, h, i, and j (8-11 respectively). | 2007 | 17963401 |
| low densities of epiphytic bacteria from the marine alga ulva australis inhibit settlement of fouling organisms. | bacteria that produce inhibitory compounds on the surface of marine algae are thought to contribute to the defense of the host plant against colonization of fouling organisms. however, the number of bacterial cells necessary to defend against fouling on the plant surface is not known. pseudoalteromonas tunicata and phaeobacter sp. strain 2.10 (formerly roseobacter gallaeciensis) are marine bacteria often found in association with the alga ulva australis and produce a range of extracellular inhib ... | 2007 | 17965210 |
| lipl32 is an extracellular matrix-interacting protein of leptospira spp. and pseudoalteromonas tunicata. | lipl32 is the major outer membrane protein in pathogenic leptospira. it is highly conserved throughout pathogenic species and is expressed in vivo during human infection. while these data suggest a role in pathogenesis, a function for lipl32 has not been defined. outer membrane proteins of gram-negative bacteria are the first line of molecular interaction with the host, and many have been shown to bind host extracellular matrix (ecm). a search for leptospiral ecm-interacting proteins identified ... | 2008 | 18285490 |
| hydrogen peroxide linked to lysine oxidase activity facilitates biofilm differentiation and dispersal in several gram-negative bacteria. | the marine bacterium pseudoalteromonas tunicata produces an antibacterial and autolytic protein, alpp, which causes death of a subpopulation of cells during biofilm formation and mediates differentiation, dispersal, and phenotypic variation among dispersal cells. the alpp homologue (loda) in the marine bacterium marinomonas mediterranea was recently identified as a lysine oxidase which mediates cell death through the production of hydrogen peroxide. here we show that alpp in p. tunicata also act ... | 2008 | 18502869 |
| analysis of the pseudoalteromonas tunicata genome reveals properties of a surface-associated life style in the marine environment. | colonisation of sessile eukaryotic host surfaces (e.g. invertebrates and seaweeds) by bacteria is common in the marine environment and is expected to create significant inter-species competition and other interactions. the bacterium pseudoalteromonas tunicata is a successful competitor on marine surfaces owing primarily to its ability to produce a number of inhibitory molecules. as such p. tunicata has become a model organism for the studies into processes of surface colonisation and eukaryotic ... | 2008 | 18813346 |
| site-specific insertion of is492 in pseudoalteromonas atlantica. | reversible insertion of is492 at a site within epsg on the pseudoalteromonas atlantica chromosome controls peripheral extracellular polysaccharide production and biofilm formation by p. atlantica. high-frequency precise excision of is492 from epsg requires 5 and 7 bp of flanking dna, suggesting that is492 transposition involves a site-specific recombination mechanism. the site specificity of is492 insertion was examined in p. atlantica and shown to be specific for a 7-bp target, 5'-cttgtta-3'. c ... | 2009 | 19684137 |
| antifouling activities expressed by marine surface associated pseudoalteromonas species. | abstract members of the marine bacterial genus pseudoalteromonas have been found in association with living surfaces and are suggested to produce bioactive compounds against settlement of algal spores, invertebrate larvae, bacteria and fungi. to determine the extent by which these antifouling activities and the production of bioactive compounds are distributed amongst the members of the genus pseudoalteromonas, 10 different pseudoalteromonas species mostly derived from different host organisms w ... | 2002 | 19709238 |
| discovery of 3-formyl-tyrosine metabolites from pseudoalteromonas tunicata through heterologous expression. | genome mining and identification of natural product gene clusters typically relies on the presence of canonical nonribosomal polypeptide synthetase (nrps) or polyketide synthase (pks) domains. recently, other condensation enzymes, such as the atp-grasp ligases, have been recognized as important players in natural product biosynthesis. in this study, sequence based searching for homologues of ddaf, the atp-grasp amide ligase from dapdiamide biosynthesis, led to the identification of a previously ... | 2010 | 20041686 |
| ability of pseudoalteromonas tunicata to colonize natural biofilms and its effect on microbial community structure. | we investigated the effectiveness of surface colonization by the epiphytic marine bacterium pseudoalteromonas tunicata firstly on a complex biofilm community on glass slides, and secondly, on the epiphytic community of ulva australis. the effectiveness of p. tunicata was compared with the performance of phaeobacter sp. 2.10, also a marine epiphytic isolate in the u. australis colonization experiments. pseudoalteromonas tunicata cells were able to colonize the glass slide community at densities f ... | 2010 | 20579099 |
| identification of compounds with bioactivity against the nematode caenorhabditis elegans by a screen based on the functional genomics of the marine bacterium pseudoalteromonas tunicata d2. | marine bacteria are a rich, yet underexplored, resource of compounds with inhibitory bioactivity against a range of eukaryotic target organisms. identification of those inhibitors, however, requires a culturable or genetically tractable producer strain, a prerequisite that is not often fulfilled. this study describes a novel functional genomic screen that is based on expression of inhibitors in a heterogeneous recombinant host (i.e., escherichia coli). functional libraries were screened by selec ... | 2010 | 20601498 |
| violacein and related tryptophan metabolites produced by chromobacterium violaceum: biosynthetic mechanism and pathway for construction of violacein core. | violacein is a natural violet pigment produced by several gram-negative bacteria, including chromobacterium violaceum, janthinobacterium lividum, and pseudoalteromonas tunicata d2, among others. this pigment has potential medical applications as antibacterial, anti-trypanocidal, anti-ulcerogenic, and anticancer drugs. the structure of violacein consists of three units: a 5-hydroxyindole, an oxindole, and a 2-pyrrolidone. the biosynthetic origins of hydrogen, nitrogen, and carbon in the pyrrolido ... | 2011 | 21779844 |
| purification and characterization of antibacterial compounds of pseudoalteromonas flavipulchra jg1. | pseudoalteromonas flavipulchra jg1 produces a protein pfap and a range of small molecular compounds with inhibitory activities against vibrio anguillarum. the pfap protein was purified from the extracellular products of jg1 by electroelution, and antibacterial activity was observed by the in-gel antibacterial assay. the complete amino acid sequence (694 aa) of pfap was determined by de novo peptide sequencing and subsequently aligning with the proteome sequence of strain jg1. the calculated mole ... | 2011 | 22194352 |
| marine bacteria from danish coastal waters show antifouling activity against the marine fouling bacterium pseudoalteromonas sp. strain s91 and zoospores of the green alga ulva australis independent of bacteriocidal activity. | the aims of this study were to determine if marine bacteria from danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. we further assess if antibacterial effect is a good proxy for antifouling activity. we isolated 110 bacteria with anti-vibrio activity from different sample types and locations during a 1-year sampling from danish coastal waters. the strains were identified as pseudoalteromonas, phaeobacter, and vibrionac ... | 2011 | 22003011 |
| membrane proteins of pseudoalteromonas tunicata during the transition from planktonic to extracellular matrix-adherent state. | pseudoalteromonas tunicata is a marine bacterium that was originally isolated from the surface of the tunicate ciona intestinalis. since c. intestinalis expresses extracellular matrix (ecm) and p. tunicata has a gene encoding a functional ecm-binding protein, we hypothesized that p. tunicata could adhere to this host via protein-ecm interactions and as a result change its membrane proteome. an in vitro adhesion assay was developed to show that p. tunicata adheres strongly to ecm. to further stud ... | 2011 | 23761287 |
| an ortholog of the leptospira interrogans lipoprotein lipl32 aids in the colonization of pseudoalteromonas tunicata to host surfaces. | the bacterium pseudoalteromonas tunicata is a common surface colonizer of marine eukaryotes, including the macroalga ulva australis.genomic analysis of p. tunicata identified genes potentially involved in surface colonization, including genes with homology to bacterial virulence factors that mediate attachment. of particular interest is the presence of a gene, designated ptll32, encoding an ortholog to the leptospira lipoprotein lipl32, which has been shown to facilitate the interaction of lepto ... | 2014 | 25071736 |
| investigating antimicrobial activity in rheinheimera sp. due to hydrogen peroxide generated by l-lysine oxidase activity. | a greenish yellow pigmented bacterial strain, designated gr5, was recently isolated from a freshwater culture pond for a soft-shell turtle. phylogenetic analyses based on 16s rrna gene sequences indicate that strain gr5 belongs to the genus rheinheimera and its only closest neighbor is the type strain of rheinheimera texasensis (98.2%). based on the antibiogram assay, strain gr5 possesses a broad spectrum of antimicrobial activity including gram-positive and gram-negative bacteria, yeast, algae, ... | 2010 | 25919624 |
| antimicrobial and cytotoxic activities of synthetically derived tambjamines c and e - j, be-18591, and a related alkaloid from the marine bacterium pseudoalteromonas tunicata. | in the first comprehensive biological assessment of the tambjamine class of marine alkaloids, synthetically derived samples of compounds 1-9 have been subjected to evaluation as antimicrobial agents and screened for their cytotoxic effects on various human cancer cell lines. most were strongly active against the fungus malassezia furfur (>amphotericin b) and showed considerable, but non-selective, antiproliferative activity against both human cancer and normal cell lines. tambjamines i and j (6 ... | 2010 | 20491087 |
| isolation and structure elucidation of a novel yellow pigment from the marine bacterium pseudoalteromonas tunicata. | the marine environment is a major source for many novel natural compounds. a new yellow pigment has been isolated from the marine bacterium p. tunicata and identified as a new member of the tambjamine class of compounds. the structural identification was achieved by a combination of 1d and 2d-nmr spectroscopy and high resolution mass spectrometry data. | 2005 | 18007521 |
| inhibition of fouling by marine bacteria immobilised in kappa-carrageenan beads. | antifouling solutions that leave little or no impact in the world's oceans are constantly being sought. this study employed the immobilisation of the antifouling bacterium pseudoalteromonas tunicata in kappa-carrageenan to demonstrate how a surface may be protected from fouling by bacteria, i.e. a 'living paint'. attempts so far to produce a 'living paint' have been limited in both longevity of effectiveness and demonstration of applicability, most noticeably regarding the lack of any field data ... | 2007 | 17653938 |
| profiling the secretome of the marine bacterium pseudoalteromonas tunicata using amine-specific isobaric tagging (itraq). | the eukaryote-associated marine bacterium pseudoalteromonas tunicata produces a range of target-specific compounds that inhibit different types of marine organisms including invertebrate larvae and algal spores, as well as a broad spectrum of fungi, protozoa, and bacteria. the ability to produce such bioactive compounds is correlated to the expression of a yellow and a purple pigment in p. tunicata. to investigate the regulation and biosynthesis of the pigments and bioactive compounds, the expre ... | 2007 | 17330939 |
| the antimicrobial activity of marinocine, synthesized by marinomonas mediterranea, is due to hydrogen peroxide generated by its lysine oxidase activity. | marinocine is a broad-spectrum antibacterial protein synthesized by the melanogenic marine bacterium marinomonas mediterranea. this work describes the basis for the antibacterial activity of marinocine and the identification of the gene coding for this protein. the antibacterial activity is inhibited under anaerobic conditions and by the presence of catalase under aerobic conditions. marinocine is active only in culture media containing l-lysine. in the presence of this amino acid, marinocine ge ... | 2006 | 16547036 |
| correlation between pigmentation and antifouling compounds produced by pseudoalteromonas tunicata. | pseudoalteromonas tunicata is a marine bacterium with the ability to prevent biofouling by the production of at least four target-specific compounds. in addition to these antifouling compounds, p. tunicata produces at least two pigments. these include a yellow and a purple pigment which, when combined, give the bacterium a dark green appearance. transposon mutagenesis was used in this study to investigate the correlation between pigment production and the expression of specific antifouling pheno ... | 2002 | 12153584 |
| inhibition of algal spore germination by the marine bacterium pseudoalteromonas tunicata. | a collection of 56 bacteria isolated from different surfaces in the marine environment were assayed for their effects on the germination of spores from the common green alga ulva lactuca. thirteen bacterial isolates were shown to inhibit spore germination. of these bacteria, pseudoalteromonas tunicata displayed the most pronounced effects against algal spores. further characterisation of the anti-algal activity of p. tunicata was performed and it was found that this bacterium produces an extrace ... | 2001 | 11248391 |
| pseudoalteromonas tunicata sp. nov., a bacterium that produces antifouling agents. | a dark-green-pigmented marine bacterium, previously designated d2, which produces components that are inhibitory to common marine fouling organisms has been characterized and assessed for taxonomic assignment. based on direct double-stranded sequencing of the 16s rrna gene, d2t was found to show the highest similarity (93%) to members of the genus pseudoalteromonas. the g + c content of d2t is 42 mol%, and it is a facultatively anaerobic rod and oxidase-positive. d2t is motile by a sheathed pola ... | 1998 | 9828422 |
| bacteria immobilised in gels: improved methodologies for antifouling and biocontrol applications. | a range of bacteria, including the marine bacterium pseudoalteromonas tunicata which produces antifouling compounds, and escherichia coli were used to investigate methods for immobilising bacteria in gels. different types of matrices were screened using the survival of barnacle nauplii as a bioassay. a dupont® polyvinylalcohol (pvoh) 10% gel was found to be the optimal matrix. this non-toxic gel remained stable in seawater while allowing for an outflux of active biological compounds from the bac ... | 2000 | 22115296 |
| pseudoalteromonas xiamenensis sp. nov., a marine bacterium isolated from coastal surface seawater. | a gram-negative, oxidase- and catalase-positive, rod-shaped, non-spore-forming, motile, aerobic bacterium, designated y2(t), was isolated from surface seawater of yundang lake, xiamen, china. the strain was able to grow in the presence of 0.5-6.0% nacl (optimum 1.0-1.5%), at ph 5-10 (optimum ph 8) and at 10-40 °c (optimum 25 °c). phylogenetic analysis based on 16s rrna gene sequences indicated that strain y2(t) belongs to the genus pseudoalteromonas, with the highest sequence similarity of 94.9% ... | 2014 | 24096356 |
| ecological roles and biotechnological applications of marine and intertidal microbial biofilms. | this review is a retrospective of ecological effects of bioactivities produced by biofilms of surface-dwelling marine/intertidal microbes as well as of the industrial and environmental biotechnologies developed exploiting the knowledge of biofilm formation. some examples of significant interest pertaining to the ecological aspects of biofilm-forming species belonging to the roseobacter clade include autochthonous bacteria from turbot larvae-rearing units with potential application as a probiotic ... | 2014 | 24817086 |
| effect of interspecific competition on trait variation in phaeobacter inhibens biofilms. | interspecific competition between bacteria shapes community dynamics, causing evolutionary changes that affect life history traits. here, we studied the role of interspecific competition on the generation of trait diversity using a two-species model system of marine, surface-associated bacteria. bacterial biofilms of phaeobacter inhibens were established alone or in competition with pseudoalteromonas tunicata and phenotypic traits of dispersal cells were assessed during biofilm development. p. i ... | 2016 | 26914307 |