scholarly journals The Marine Bacterium Pseudoalteromonas Tunicata Alters its Proteome Upon Adhesion to Extracellular Matrix

2008 ◽  
Vol S2 (01) ◽  
pp. 256-256
Author(s):  
D. E. Hoke ◽  
K. Zhang ◽  
S. Egan ◽  
B. Adler
Keyword(s):  
Extracellular Matrix ◽  
Marine Bacterium ◽  
Pseudoalteromonas Tunicata

Antimicrobial and Cytotoxic Activities of Synthetically Derived Tambjamines C and E - J, BE-18591, and a Related Alkaloid from the Marine Bacterium Pseudoalteromonas tunicata

2010 ◽  
Vol 7 (5) ◽  
pp. 1311-1324 ◽  
Author(s):  
David M. Pinkerton ◽  
Martin G. Banwell ◽  
Mary J. Garson ◽  
Naresh Kumar ◽  
Manoel Odorico de Moraes ◽  
...  
Keyword(s):  
Marine Bacterium ◽  
Cytotoxic Activities ◽  
Related Alkaloid ◽  
Pseudoalteromonas Tunicata

scholarly journals 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

2010 ◽  
Vol 76 (17) ◽  
pp. 5710-5717 ◽  
Author(s):  
Francesco Ballestriero ◽  
Torsten Thomas ◽  
Catherine Burke ◽  
Suhelen Egan ◽  
Staffan Kjelleberg
Keyword(s):  
Caenorhabditis Elegans ◽  
Marine Bacterium ◽  
Model Organism ◽  
Genomic Analysis ◽  
Microscopic Analysis ◽  
Intestinal Lumen ◽  
Functional Genomic ◽  
Chemical Structures ◽  
Genomic Screen ◽  
Pseudoalteromonas Tunicata

ABSTRACT 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 selective grazing by the nematode Caenorhabditis elegans, in a simple, rapid, high-throughput manner. We applied our approach to discover inhibitors of C. elegans produced by the marine bacterium Pseudoalteromonas tunicata D2, a model organism for exploring a range of antagonistic activities between bacteria and eukaryotes and a known producer of several toxic compounds. Expression of P. tunicata DNA in E. coli and grazing selection by the nematode Caenorhabditis elegans identified two clones, with slow- and fast-killing modes of action. Genomic analysis of the slow-killing clone revealed that the activity was due to a small molecule, tambjamine, while the fast-killing activity involved a gene encoding for a novel protein. Microscopic analysis showed substantial colonization of the intestinal lumen, or rapid death of the nematode without colonization, for the two activities, respectively. The novel functional genomic screen presented here therefore detects new eukaryotic inhibitors with different chemical structures, kinetics, and predicted modes of actions.

scholarly journals LipL32 Is an Extracellular Matrix-Interacting Protein of Leptospira spp. and Pseudoalteromonas tunicata

2008 ◽  
Vol 76 (5) ◽  
pp. 2063-2069 ◽  
Author(s):  
David E. Hoke ◽  
Suhelen Egan ◽  
Paul A. Cullen ◽  
Ben Adler
Keyword(s):  
Extracellular Matrix ◽  
Membrane Protein ◽  
Outer Membrane ◽  
Outer Membrane Protein ◽  
Outer Membrane Proteins ◽  
Major Outer Membrane Protein ◽  
Interacting Proteins ◽  
Orthologous Protein ◽  
Pseudoalteromonas Tunicata

ABSTRACT 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 the major outer membrane protein, LipL32. To verify this finding, recombinant LipL32 was expressed in Escherichia coli and was found to bind Matrigel ECM and individual components of ECM, including laminin, collagen I, and collagen V. Likewise, an orthologous protein found in the genome of Pseudoalteromonas tunicata strain D2 was expressed and found to be functionally similar and immunologically cross-reactive. Lastly, binding activity was mapped to the C-terminal 72 amino acids. These studies show that LipL32 and an orthologous protein in P. tunicata are immunologically cross-reactive and function as ECM-interacting proteins via a conserved C-terminal region.

scholarly journals Ecological Advantages of Autolysis during the Development and Dispersal of Pseudoalteromonas tunicata Biofilms

2006 ◽  
Vol 72 (8) ◽  
pp. 5414-5420 ◽  
Author(s):  
Anne Mai-Prochnow ◽  
Jeremy S. Webb ◽  
Belinda C. Ferrari ◽  
Staffan Kjelleberg
Keyword(s):  
Biofilm Formation ◽  
Marine Bacterium ◽  
Wild Type ◽  
Antibacterial Protein ◽  
Phenotypic Diversification ◽  
Pseudoalteromonas Tunicata ◽  
Two Parameters ◽  
Biofilm Development ◽  
First Time ◽  
Successful Colonization

ABSTRACT 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 biofilm development. The dispersal was not observed with a ΔAlpP mutant strain. Using flow cytometry and the fluorescent dye DiBAC4(3), we also show that P. tunicata wild-type cells that disperse from biofilms have enhanced metabolic activity compared to those cells that disperse from ΔAlpP mutant biofilms, possibly due to nutrients released from dead cells. Furthermore, we report that there was considerable phenotypic variation among cells dispersing from wild-type biofilms but not from the ΔAlpP mutant. Wild-type cells that dispersed from biofilms showed significantly increased variations in growth, motility, and biofilm formation, which may be important for successful colonization of new surfaces. These findings suggest for the first time that the autocidal events mediated by an antibacterial protein can confer ecological advantages to the species by generating a metabolically active and phenotypically diverse subpopulation of dispersal cells.

scholarly journals Independent host- and bacterium-based determinants protect a model symbiosis from phage predation

2021 ◽  
Author(s):  
Jonathan B Lynch ◽  
Brittany D Bennett ◽  
Bryan D Merrill ◽  
Edward G Ruby ◽  
Andrew J Hryckowian
Keyword(s):  
Extracellular Matrix ◽  
Microbial Communities ◽  
Marine Bacterium ◽  
Vibrio Fischeri ◽  
Euprymna Scolopes ◽  
Ambient Seawater ◽  
Bacterial Populations ◽  
Microbial Ecosystems ◽  
Shed Light

Bacteriophages (phages) are diverse and abundant constituents of microbial communities worldwide, and are capable of modulating bacterial populations in diverse ways. Here we describe a novel phage, ϕHNL01, which infects the marine bacterium Vibrio fischeri. We use culture-based approaches to demonstrate that mutations in the exopolysaccharide locus of V. fischeri render this bacterium resistant to infection by ϕHNL01, highlighting the extracellular matrix as a key determinant of phage tropism in this interaction. Additionally, using the natural symbiosis between V. fischeri and the squid Euprymna scolopes, we show that during colonization, V. fischeri is protected from phage present in the ambient seawater. Taken together, these findings shed light on independent yet synergistic host- and bacterium-based strategies for resisting symbiosis-disrupting phage predation, and present important implications for understanding these strategies in the context of host-associated microbial ecosystems.

scholarly journals Competitive Interactions in Mixed-Species Biofilms Containing the Marine Bacterium Pseudoalteromonas tunicata

2005 ◽  
Vol 71 (4) ◽  
pp. 1729-1736 ◽  
Author(s):  
Dhana Rao ◽  
Jeremy S. Webb ◽  
Staffan Kjelleberg
Keyword(s):  
Marine Bacterium ◽  
Fluorescent Protein ◽  
16S Rrna Gene Sequencing ◽  
Single Species ◽  
Rrna Gene ◽  
Mixed Species ◽  
Pseudoalteromonas Tunicata ◽  
Rrna Gene Sequencing ◽  
Green Fluorescent ◽  
Eukaryotic Organisms

ABSTRACT 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 hypothesis that P. tunicata is a superior competitor compared with other bacteria isolated from the plant. A number of U. lactuca bacterial isolates were (i) identified by 16S rRNA gene sequencing, (ii) characterized for the production of or sensitivity to extracellular antibacterial proteins, and (iii) labeled with a fluorescent color tag (either the red fluorescent protein DsRed or green fluorescent protein). We then grew single- and mixed-species bacterial biofilms containing P. tunicata in glass flow cell reactors. In pure culture, all the marine isolates formed biofilms containing microcolony structures within 72 h. However, in mixed-species biofilms, P. tunicata removed the competing strain unless its competitor was relatively insensitive to AlpP (Pseudoalteromonas gracilis) or produced strong inhibitory activity against P. tunicata (Roseobacter gallaeciensis). Moreover, biofilm studies conducted with an AlpP− mutant of P. tunicata indicated that the mutant was less competitive when it was introduced into preestablished biofilms, suggesting that AlpP has a role during competitive biofilm formation. When single-species biofilms were allowed to form microcolonies before the introduction of a competitor, these microcolonies coexisted with P. tunicata for extended periods of time before they were removed. Two marine bacteria (R. gallaeciensis and P. tunicata) were superior competitors in this study. Our data suggest that this dominance can be attributed to the ability of these organisms to rapidly form microcolonies and their ability to produce extracellular antibacterial compounds.

scholarly journals Biofilm Development and Cell Death in the Marine Bacterium Pseudoalteromonas tunicata

2004 ◽  
Vol 70 (6) ◽  
pp. 3232-3238 ◽  
Author(s):  
Anne Mai-Prochnow ◽  
Flavia Evans ◽  
Doralyn Dalisay-Saludes ◽  
Sacha Stelzer ◽  
Suhelen Egan ◽  
...  
Keyword(s):  
Cell Death ◽  
Marine Environment ◽  
Marine Bacterium ◽  
Culture Conditions ◽  
Viable Cells ◽  
Inhibitory Compounds ◽  
Mutant Derivative ◽  
Pseudoalteromonas Tunicata ◽  
Biofilm Development ◽  
Invertebrate Larvae

ABSTRACT 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 exhibited a characteristic architecture consisting of differentiated microcolonies surrounded by water channels. Remarkably, we observed a repeatable pattern of cell death during biofilm development of P. tunicata, similar to that recently reported for biofilms of Pseudomonas aeruginosa (J. S. Webb et al., J. Bacteriol. 185:4585-4595, 2003). Killing and lysis occurred inside microcolonies, apparently resulting in the formation of voids within these structures. A subpopulation of viable cells was always observed within the regions of killing in the biofilm. Moreover, extensive killing in mature biofilms appeared to result in detachment of the biofilm from the substratum. A novel 190-kDa autotoxic protein produced by P. tunicata, designated AlpP, was found to be involved in this biofilm killing and detachment. A ΔalpP mutant derivative of P. tunicata was generated, and this mutant did not show cell death during biofilm development. We propose that AlpP-mediated cell death plays an important role in the multicellular biofilm development of P. tunicata and subsequent dispersal of surviving cells within the marine environment.

scholarly journals Inhibition of algal spore germination by the marine bacterium Pseudoalteromonas tunicata

2001 ◽  
Vol 35 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Suhelen Egan ◽  
Sally James ◽  
Carola Holmström ◽  
Staffan Kjelleberg
Keyword(s):  
Spore Germination ◽  
Marine Bacterium ◽  
Pseudoalteromonas Tunicata
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