Serratia liquefaciens

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Leo Eberl - One of the best experts on this subject based on the ideXlab platform.

  • Serratiain Control of Swarming Motility of Two Separate Regulatory Systems Participate
    2016
    Co-Authors: Staffan Kjelleberg, Michael Givskov, Gunna Christiansen, Søren Molin, Jörgen Östling, Allan Beck Christensen, Soeren Molin, Leo Eberl
    Abstract:

    Two separate regulatory systems participate in control of swarming motility of Serratia liquefaciens MG

  • Control of exoenzyme production, motility and cell differentiation in Serratia liquefaciens
    FEMS Microbiology Letters, 2006
    Co-Authors: Michael Givskov, Leo Eberl, Søren Molin
    Abstract:

    Serratia liquefaciens secretes a broad spectrum of hydrolytic enzymes to the surrounding medium and possesses the ability to differentiate into specialized swarmer cells capable of rapid surface motility. Control of exoenzyme production and swarming motility is governed by similar regulatory components, including a quorum-sensing mechanism and the flagellar master operon flhDC.

  • Identification and characterization of a GDSL esterase gene located proximal to the swr quorum-sensing system of Serratia liquefaciens MG1.
    Applied and environmental microbiology, 2003
    Co-Authors: Kathrin Riedel, Michael Givskov, Daniela Talker-huiber, Helmut Schwab, Leo Eberl
    Abstract:

    Serratia liquefaciens MG1 employs the swr quorum-sensing system to control various functions, including production of extracellular enzymes and swarming motility. Here we report the sequencing of the swr flanking DNA regions. We identified a gene upstream of swrR and transcribed in the same direction, designated estA, which encodes an esterase that belongs to family II of lipolytic enzymes. EstA was heterologously expressed in Escherichia coli, and the substrate specificity of the enzyme was determined in crude extracts. With the aid of zymograms visualizing EstA on polyacrylamide gels and by the analysis of a transcriptional fusion of the estA promoter to the promoterless luxAB genes, we showed that expression of the esterase is not regulated by the swr quorum-sensing system. An estA mutant was generated and was found to exhibit growth defects on minimal medium containing Tween 20 or Tween 80 as the sole carbon source. Moreover, we show that the mutant produces greatly reduced amounts of N-acyl-homoserine lactone (AHL) signal molecules on Tween-containing medium compared with the wild type, suggesting that under certain growth conditions EstA may be important for providing the cell with precursors required for AHL biosynthesis.

  • N-acyl-L-homoserine lactone-mediated regulation of the lip secretion system in Serratia liquefaciens MG1.
    Journal of bacteriology, 2001
    Co-Authors: Kathrin Riedel, Michael Givskov, Thomas Ohnesorg, Karen A. Krogfelt, Thomas Steen Hansen, Kenji Omori, Leo Eberl
    Abstract:

    The analysis of Serratia liquefaciens MG1 ′ luxAB insertion mutants that are responsive to N -butanoyl-l-homoserine lactone revealed that expression of lipB is controlled by the swr quorum-sensing system. LipB is part of the Lip exporter, a type I secretion system, which is responsible for the secretion of extracellular lipase, metalloprotease, and S-layer protein.

  • Assessment of flhDC mRNA levels in Serratia liquefaciens swarm cells.
    Journal of bacteriology, 2000
    Co-Authors: Tim Tolker-nielsen, Leo Eberl, Thomas Bovbjerg Rasmussen, Claus Sternberg, Søren Molin, Allan Beck Christensen, Kim Holmstrøm, Arne Heydorn, Michael Givskov
    Abstract:

    Swarming motility is an intrinsically linked surface and cell density phenomenon. Surface exposure leads to a differentiation process that transforms cells into multinucleate, aseptate, and profusely flagellated swarm cells that are highly elongated (see reference 16 for a review). The cells of a swarming colony have the ability to migrate coordinately in rafts away from the center of the colony. The combined action of cells involved in motility and cells involved in cell division and growth results in colony expansion and rapid colonization of all of the available surface. In the uropathogen Proteus mirabilis it has been demonstrated that swarming behavior is closely associated with modulation of virulence characteristics and the ability to invade human urothelial cells (1–3). In Vibrio parahaemolyticus differentiation into swarm cells plays an important role in adsorption to and colonization of chitinaceous shells of crustaceans (4). For the opportunistic pathogen Serratia liquefaciens, evidence that expression of the phospholipase gene (phlA), which encodes a potential virulence determinant, is differentially expressed in swarm cells has been presented (6). In S. liquefaciens MG1, the swarming phenomenon is linked to high cell density by means of a quorum-sensing mechanism (7, 14). Quorum sensing controls production of the extracellular biosurfactant serrawettin W2, which is required for swarm cells to travel atop the agar surface and which enables swarm colony expansion (21). The flhDC operon appears to play a crucial role in the swarm cell differentiation process. In both S. liquefaciens and P. mirabilis artificial and prolonged overexpression of the flhDC operon dramatically enhances cell elongation and causes increased flagellation (6, 10). Moreover, for P. mirabilis it has been demonstrated (by Northern analysis) that the amount of flhDC mRNA is increased more than 30-fold in swarm cells compared to the amount found in vegetative cells (10). Previously it was shown that S. liquefaciens swarm cells carry more flagella and express higher levels of phospholipase (PhlA) than their vegetative counterparts (6). Since artificial overexpression of flhDC in S. liquefaciens also leads to cell elongation and increased phospholipase and flagellar expression (6, 13), the apparent synchronization of swarm cell differentiation with phlA and flagellum expression would be most readily explained by assuming that, as in P. mirabilis, the level of flhDC mRNA is specifically increased in swarm cells. However, here we present evidence that the level of flhDC mRNA in S. liquefaciens swarm cells is within the range of levels found in vegetative cells, which suggests that surface-induced S. liquefaciens swarm cell differentiation, although dependent on flhDC gene expression, does not occur through elevated flhDC mRNA levels.

Michael Givskov - One of the best experts on this subject based on the ideXlab platform.

  • Serratiain Control of Swarming Motility of Two Separate Regulatory Systems Participate
    2016
    Co-Authors: Staffan Kjelleberg, Michael Givskov, Gunna Christiansen, Søren Molin, Jörgen Östling, Allan Beck Christensen, Soeren Molin, Leo Eberl
    Abstract:

    Two separate regulatory systems participate in control of swarming motility of Serratia liquefaciens MG

  • Control of exoenzyme production, motility and cell differentiation in Serratia liquefaciens
    FEMS Microbiology Letters, 2006
    Co-Authors: Michael Givskov, Leo Eberl, Søren Molin
    Abstract:

    Serratia liquefaciens secretes a broad spectrum of hydrolytic enzymes to the surrounding medium and possesses the ability to differentiate into specialized swarmer cells capable of rapid surface motility. Control of exoenzyme production and swarming motility is governed by similar regulatory components, including a quorum-sensing mechanism and the flagellar master operon flhDC.

  • Quorum Sensing-Controlled Biofilm Development in Serratia liquefaciens MG1
    Journal of bacteriology, 2004
    Co-Authors: Maurizio Labbate, Michael Givskov, Scott A. Rice, Shu Yeong Queck, Kai Shyang Koh, Staffan Kjelleberg
    Abstract:

    Serratia liquefaciens MG1 contains an N-acylhomoserine lactone-mediated quorum-sensing system that is known to regulate swarming motility colonization. In this study, we describe for S. liquefaciens MG1 the development of a novel biofilm consisting of cell aggregates and differentiated cell types, such as cell chains and long filamentous cells. Furthermore, quorum sensing is shown to be crucial for normal biofilm development and for elaborate differentiation. A mutant of S. liquefaciens MG1 that was incapable of synthesizing extracellular signal formed a thin and nonmature biofilm lacking cell aggregates and differentiated cell chains. Signal-based complementation of this mutant resulted in a biofilm with the wild-type architecture. Two quorum-sensing-regulated genes (bsmA and bsmB) involved in biofilm development were identified, and we propose that these genes are engaged in fine-tuning the formation of cell aggregates at a specific point in biofilm development.

  • Identification and characterization of a GDSL esterase gene located proximal to the swr quorum-sensing system of Serratia liquefaciens MG1.
    Applied and environmental microbiology, 2003
    Co-Authors: Kathrin Riedel, Michael Givskov, Daniela Talker-huiber, Helmut Schwab, Leo Eberl
    Abstract:

    Serratia liquefaciens MG1 employs the swr quorum-sensing system to control various functions, including production of extracellular enzymes and swarming motility. Here we report the sequencing of the swr flanking DNA regions. We identified a gene upstream of swrR and transcribed in the same direction, designated estA, which encodes an esterase that belongs to family II of lipolytic enzymes. EstA was heterologously expressed in Escherichia coli, and the substrate specificity of the enzyme was determined in crude extracts. With the aid of zymograms visualizing EstA on polyacrylamide gels and by the analysis of a transcriptional fusion of the estA promoter to the promoterless luxAB genes, we showed that expression of the esterase is not regulated by the swr quorum-sensing system. An estA mutant was generated and was found to exhibit growth defects on minimal medium containing Tween 20 or Tween 80 as the sole carbon source. Moreover, we show that the mutant produces greatly reduced amounts of N-acyl-homoserine lactone (AHL) signal molecules on Tween-containing medium compared with the wild type, suggesting that under certain growth conditions EstA may be important for providing the cell with precursors required for AHL biosynthesis.

  • Quantitative effects of medium hardness and nutrient availability on the swarming motility of Serratia liquefaciens.
    Bulletin of mathematical biology, 2002
    Co-Authors: Martin A. Bees, Peter Andresen, Erik Mosekilde, Michael Givskov
    Abstract:

    We report the first controlled measurements of expansion rates for swarming colonies of Serratia liquefaciens under different growth conditions, combined with qualitative observations of the organization of the colony into regions of differentiated cell types. Significantly, the results reveal that swarming colonies of S. liquefaciens can have an increasing expansion rate with time. We compare and contrast the expansion rate results with predictions from a recent mathematical model which coupled key hydrodynamical and biological mechanisms. Furthermore, we investigate whether the swarming colonies grow according to a power law or exponentially (for large times), as suggested by recent theoretical results.

Søren Molin - One of the best experts on this subject based on the ideXlab platform.

  • Serratiain Control of Swarming Motility of Two Separate Regulatory Systems Participate
    2016
    Co-Authors: Staffan Kjelleberg, Michael Givskov, Gunna Christiansen, Søren Molin, Jörgen Östling, Allan Beck Christensen, Soeren Molin, Leo Eberl
    Abstract:

    Two separate regulatory systems participate in control of swarming motility of Serratia liquefaciens MG

  • Control of exoenzyme production, motility and cell differentiation in Serratia liquefaciens
    FEMS Microbiology Letters, 2006
    Co-Authors: Michael Givskov, Leo Eberl, Søren Molin
    Abstract:

    Serratia liquefaciens secretes a broad spectrum of hydrolytic enzymes to the surrounding medium and possesses the ability to differentiate into specialized swarmer cells capable of rapid surface motility. Control of exoenzyme production and swarming motility is governed by similar regulatory components, including a quorum-sensing mechanism and the flagellar master operon flhDC.

  • Assessment of flhDC mRNA levels in Serratia liquefaciens swarm cells.
    Journal of bacteriology, 2000
    Co-Authors: Tim Tolker-nielsen, Leo Eberl, Thomas Bovbjerg Rasmussen, Claus Sternberg, Søren Molin, Allan Beck Christensen, Kim Holmstrøm, Arne Heydorn, Michael Givskov
    Abstract:

    Swarming motility is an intrinsically linked surface and cell density phenomenon. Surface exposure leads to a differentiation process that transforms cells into multinucleate, aseptate, and profusely flagellated swarm cells that are highly elongated (see reference 16 for a review). The cells of a swarming colony have the ability to migrate coordinately in rafts away from the center of the colony. The combined action of cells involved in motility and cells involved in cell division and growth results in colony expansion and rapid colonization of all of the available surface. In the uropathogen Proteus mirabilis it has been demonstrated that swarming behavior is closely associated with modulation of virulence characteristics and the ability to invade human urothelial cells (1–3). In Vibrio parahaemolyticus differentiation into swarm cells plays an important role in adsorption to and colonization of chitinaceous shells of crustaceans (4). For the opportunistic pathogen Serratia liquefaciens, evidence that expression of the phospholipase gene (phlA), which encodes a potential virulence determinant, is differentially expressed in swarm cells has been presented (6). In S. liquefaciens MG1, the swarming phenomenon is linked to high cell density by means of a quorum-sensing mechanism (7, 14). Quorum sensing controls production of the extracellular biosurfactant serrawettin W2, which is required for swarm cells to travel atop the agar surface and which enables swarm colony expansion (21). The flhDC operon appears to play a crucial role in the swarm cell differentiation process. In both S. liquefaciens and P. mirabilis artificial and prolonged overexpression of the flhDC operon dramatically enhances cell elongation and causes increased flagellation (6, 10). Moreover, for P. mirabilis it has been demonstrated (by Northern analysis) that the amount of flhDC mRNA is increased more than 30-fold in swarm cells compared to the amount found in vegetative cells (10). Previously it was shown that S. liquefaciens swarm cells carry more flagella and express higher levels of phospholipase (PhlA) than their vegetative counterparts (6). Since artificial overexpression of flhDC in S. liquefaciens also leads to cell elongation and increased phospholipase and flagellar expression (6, 13), the apparent synchronization of swarm cell differentiation with phlA and flagellum expression would be most readily explained by assuming that, as in P. mirabilis, the level of flhDC mRNA is specifically increased in swarm cells. However, here we present evidence that the level of flhDC mRNA in S. liquefaciens swarm cells is within the range of levels found in vegetative cells, which suggests that surface-induced S. liquefaciens swarm cell differentiation, although dependent on flhDC gene expression, does not occur through elevated flhDC mRNA levels.

  • Two Separate Regulatory Systems Participate in Control of Swarming Motility of Serratia liquefaciens MG1
    Journal of bacteriology, 1998
    Co-Authors: Michael Givskov, Leo Eberl, Gunna Christiansen, Søren Molin, Jörgen Östling, Peter W. Lindum, Allan Beck Christensen, Staffan Kjelleberg
    Abstract:

    Swarming motility of Serratia liquefaciens MG1 requires the expression of two genetic loci, flhDC and swrI. Here we demonstrate that the products of the flhDC operon (the flagellar master regulator) and the swrI gene (the extracellular signal molecule N-butanoyl-L-homoserine lactone) are global regulators which control two separate regulons.

  • involvement of n acyl l homoserine lactone autoinducers in controlling the multicellular behaviour of Serratia liquefaciens
    Molecular Microbiology, 1996
    Co-Authors: Leo Eberl, Siri Ram Chhabra, Barrie W. Bycroft, Gordon S. A. B. Stewart, Paul Williams, Michael K. Winson, Claus Sternberg, Gunna Christiansen, Søren Molin, Michael Givskov
    Abstract:

    Summary Several bacterial species possess the ability to differentiate into highly motile swarmer cells capable of rapid surface colonization. In Serratia liquefaciens, we demonstrate that initiation of swarmer-cell differentiation involves diffusible signal molecules that are released into the growth medium. Using high-performance liquid chromatography (HPLC), high resolution mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, we identified N-butanoyl-l-homoserine lactone (BHL) and N-hexanoyl-l-homoserine lactone (HHL) in cell-free Serratia culture supernatants. BHL and HHL are present in a ratio of approximately 10:1 and their structures were unequivocally confirmed by chemical synthesis. The swrlswarmer initiation) gene, the predicted translation product of which exhibits substantial homology to the Luxl family of putative Nacyl homoserine lactone (AHL) synthases is responsible for directing synthesis of both BHL and HHL. In an swrl mutant, swarming motility is abolished but can be restored by the addition of an exogenous AHL. These results add swarming motility to the rapidly expanding list of phenotypes known to be controlled through quorum sensing.

Gunna Christiansen - One of the best experts on this subject based on the ideXlab platform.

  • Serratiain Control of Swarming Motility of Two Separate Regulatory Systems Participate
    2016
    Co-Authors: Staffan Kjelleberg, Michael Givskov, Gunna Christiansen, Søren Molin, Jörgen Östling, Allan Beck Christensen, Soeren Molin, Leo Eberl
    Abstract:

    Two separate regulatory systems participate in control of swarming motility of Serratia liquefaciens MG

  • Two Separate Regulatory Systems Participate in Control of Swarming Motility of Serratia liquefaciens MG1
    Journal of bacteriology, 1998
    Co-Authors: Michael Givskov, Leo Eberl, Gunna Christiansen, Søren Molin, Jörgen Östling, Peter W. Lindum, Allan Beck Christensen, Staffan Kjelleberg
    Abstract:

    Swarming motility of Serratia liquefaciens MG1 requires the expression of two genetic loci, flhDC and swrI. Here we demonstrate that the products of the flhDC operon (the flagellar master regulator) and the swrI gene (the extracellular signal molecule N-butanoyl-L-homoserine lactone) are global regulators which control two separate regulons.

  • involvement of n acyl l homoserine lactone autoinducers in controlling the multicellular behaviour of Serratia liquefaciens
    Molecular Microbiology, 1996
    Co-Authors: Leo Eberl, Siri Ram Chhabra, Barrie W. Bycroft, Gordon S. A. B. Stewart, Paul Williams, Michael K. Winson, Claus Sternberg, Gunna Christiansen, Søren Molin, Michael Givskov
    Abstract:

    Summary Several bacterial species possess the ability to differentiate into highly motile swarmer cells capable of rapid surface colonization. In Serratia liquefaciens, we demonstrate that initiation of swarmer-cell differentiation involves diffusible signal molecules that are released into the growth medium. Using high-performance liquid chromatography (HPLC), high resolution mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, we identified N-butanoyl-l-homoserine lactone (BHL) and N-hexanoyl-l-homoserine lactone (HHL) in cell-free Serratia culture supernatants. BHL and HHL are present in a ratio of approximately 10:1 and their structures were unequivocally confirmed by chemical synthesis. The swrlswarmer initiation) gene, the predicted translation product of which exhibits substantial homology to the Luxl family of putative Nacyl homoserine lactone (AHL) synthases is responsible for directing synthesis of both BHL and HHL. In an swrl mutant, swarming motility is abolished but can be restored by the addition of an exogenous AHL. These results add swarming motility to the rapidly expanding list of phenotypes known to be controlled through quorum sensing.

  • Involvement of N‐acyl‐l‐homoserine lactone autoinducers in controlling the multicellular behaviour of Serratia liquefaciens
    Molecular microbiology, 1996
    Co-Authors: Leo Eberl, Siri Ram Chhabra, Barrie W. Bycroft, Gordon S. A. B. Stewart, Paul Williams, Michael K. Winson, Claus Sternberg, Gunna Christiansen, Søren Molin, Michael Givskov
    Abstract:

    Summary Several bacterial species possess the ability to differentiate into highly motile swarmer cells capable of rapid surface colonization. In Serratia liquefaciens, we demonstrate that initiation of swarmer-cell differentiation involves diffusible signal molecules that are released into the growth medium. Using high-performance liquid chromatography (HPLC), high resolution mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy, we identified N-butanoyl-l-homoserine lactone (BHL) and N-hexanoyl-l-homoserine lactone (HHL) in cell-free Serratia culture supernatants. BHL and HHL are present in a ratio of approximately 10:1 and their structures were unequivocally confirmed by chemical synthesis. The swrlswarmer initiation) gene, the predicted translation product of which exhibits substantial homology to the Luxl family of putative Nacyl homoserine lactone (AHL) synthases is responsible for directing synthesis of both BHL and HHL. In an swrl mutant, swarming motility is abolished but can be restored by the addition of an exogenous AHL. These results add swarming motility to the rapidly expanding list of phenotypes known to be controlled through quorum sensing.

  • Differentiation of Serratia liquefaciens into swarm cells is controlled by the expression of the flhD master operon.
    Journal of bacteriology, 1996
    Co-Authors: Leo Eberl, Gunna Christiansen, Søren Molin, Michael Givskov
    Abstract:

    The velocity with which a swarming colony of Serratia liquefaciens colonizes the surface of a suitable solid substratum was controlled by modulating the expression of the flhD master operon. In liquid medium, the stimulation of flhD expression resulted in filamentous, multinucleate, and hyperflagellated cells that were indistinguishable from swarm cells isolated from the edge of a swarm colony. Thus, expression of the flhD master operon appears to play a central role in the process of swarm cell differentiation.

Staffan Kjelleberg - One of the best experts on this subject based on the ideXlab platform.

  • Serratiain Control of Swarming Motility of Two Separate Regulatory Systems Participate
    2016
    Co-Authors: Staffan Kjelleberg, Michael Givskov, Gunna Christiansen, Søren Molin, Jörgen Östling, Allan Beck Christensen, Soeren Molin, Leo Eberl
    Abstract:

    Two separate regulatory systems participate in control of swarming motility of Serratia liquefaciens MG

  • Quorum Sensing-Controlled Biofilm Development in Serratia liquefaciens MG1
    Journal of bacteriology, 2004
    Co-Authors: Maurizio Labbate, Michael Givskov, Scott A. Rice, Shu Yeong Queck, Kai Shyang Koh, Staffan Kjelleberg
    Abstract:

    Serratia liquefaciens MG1 contains an N-acylhomoserine lactone-mediated quorum-sensing system that is known to regulate swarming motility colonization. In this study, we describe for S. liquefaciens MG1 the development of a novel biofilm consisting of cell aggregates and differentiated cell types, such as cell chains and long filamentous cells. Furthermore, quorum sensing is shown to be crucial for normal biofilm development and for elaborate differentiation. A mutant of S. liquefaciens MG1 that was incapable of synthesizing extracellular signal formed a thin and nonmature biofilm lacking cell aggregates and differentiated cell chains. Signal-based complementation of this mutant resulted in a biofilm with the wild-type architecture. Two quorum-sensing-regulated genes (bsmA and bsmB) involved in biofilm development were identified, and we propose that these genes are engaged in fine-tuning the formation of cell aggregates at a specific point in biofilm development.

  • How Delisea pulchra furanones affect quorum sensing and swarming motility in Serratia liquefaciens MG1.
    Microbiology (Reading England), 2000
    Co-Authors: Thomas Bovbjerg Rasmussen, Michael Manefield, Staffan Kjelleberg, Leo Eberl, Peter Steinberg, Jens Bo Andersen, Uffe Anthoni, Carsten Christophersen, Michael Givskov
    Abstract:

    Halogenated furanones produced by the benthic marine macroalga Delisea pulchra inhibit swarming motility of Serratia liquefaciens MG1. This study demonstrates that exogenously added furanones control transcription of the quorum sensing regulated gene swrA in competition with the cognate signal molecule N:-butanoyl-L-homoserine lactone. This in turn results in reduced production of the surface-active compound serrawettin W2, which is crucial for surface translocation of the differentiated swarm cells. It is demonstrated that furanones interfere with interspecies communication during swarming of mixed cultures and that the mode of interference in quorum-sensing control and interspecies communication is not through inhibition of autoinducer synthesis.

  • Two Separate Regulatory Systems Participate in Control of Swarming Motility of Serratia liquefaciens MG1
    Journal of bacteriology, 1998
    Co-Authors: Michael Givskov, Leo Eberl, Gunna Christiansen, Søren Molin, Jörgen Östling, Peter W. Lindum, Allan Beck Christensen, Staffan Kjelleberg
    Abstract:

    Swarming motility of Serratia liquefaciens MG1 requires the expression of two genetic loci, flhDC and swrI. Here we demonstrate that the products of the flhDC operon (the flagellar master regulator) and the swrI gene (the extracellular signal molecule N-butanoyl-L-homoserine lactone) are global regulators which control two separate regulons.

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