Blar i forfatter "Hansen, Hilde"
-
The alternative sigma factor RpoQ regulates colony morphology, biofilm formation and motility in the fish pathogen Aliivibrio salmonicida
Khider, Miriam; Willassen, Nils Peder; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-09-12)<i>Background</i>: Quorum sensing (QS) is a cell-to cell communication system that bacteria use to synchronize activities as a group. LitR, the master regulator of QS in <i>Aliivibrio salmonicida</i>, was recently shown to regulate activities such as motility, rugosity and biofilm formation in a temperature dependent manner. LitR was also found to be a positive regulator of <i>rpoQ</i>. RpoQ ... -
The autoinducer synthases LuxI and AinS are responsible for temperature-dependent AHL production in the fish pathogen Aliivibrio salmonicida
Hansen, Hilde; Purohit, Amit Anand; Leiros, Hanna-Kirsti S.; Johansen, Jostein; Kellermann, Stefanie J.; Bjelland, Ane Mohn; Willassen, Nils Peder (Journal article; Tidsskriftartikkel, 2015-03-24)Background: Quorum sensing (QS) is a cell-to-cell communication system used by bacteria to regulate activities such as virulence, bioluminescence and biofilm formation. The most common QS signals in Gram-negative bacteria are N-acyl-homoserine lactones (AHLs). Aliivibrio salmonicida is the etiological agent of cold water vibriosis in Atlantic salmon, a disease which occurs mainly during seasons ... -
Complete genome sequence of Photobacterium ganghwense C2.2: A new polyhydroxyalkanoate production candidate
Lascu, Irina; Mereuță, Ioana; Chiciudean, Iulia; Hansen, Hilde; Avramescu, Sorin Marius; Tănase, Ana-Maria; Stoica, Ileana (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-01)Polyhydroxyalkanoates (PHAs) are biodegradable bioplastics that can be manufactured sustainably and represent a promising green alternative to petrochemical-based plastics. Here, we describe the complete genome of a new marine PHA-producing bacterium—Photobacterium ganghwense (strain C2.2), which we have isolated from the Black Sea seashore. This new isolate is psychrotolerant and accumulates PHA ... -
Construction of a fur null mutant and RNA-sequencing provide deeper global understanding of the Aliivibrio salmonicida Fur regulon
Thode, Sunniva Katharina; Bækkedal, Cecilie; Söderberg, Jenny Johansson; Hjerde, Erik; Hansen, Hilde; Haugen, Peik (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-07-13)<i>Background:</i> The ferric uptake regulator (Fur) is a transcription factor and the main regulator of iron acquisition in prokaryotes. When bound to ferric iron, Fur recognizes its DNA binding site and generally executes its function by repressing transcription of its target genes. Due to its importance in virulence, the Fur regulon is well studied for several model bacteria. In our previous ... -
Differential expression profiling of ΔlitR and ΔrpoQ mutants reveals insight into QS regulation of motility, adhesion and biofilm formation in Aliivibrio salmonicida
Khider, Miriam; Hjerde, Erik; Hansen, Hilde; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-03-15)<i>Background</i>: The coordination of group behaviors in bacteria is achieved by a cell-cell signaling process called quorum sensing (QS). QS is an intercellular communication system, which synchronously controls expression of a vast range of genes in response to changes in cell density and is mediated by autoinducers that act as extracellular signals. <i>Aliivibrio salmonicida</i>, the causative ... -
Exploring the transcriptome of luxI- and ΔainS mutants and the impact of N-3-oxo-hexanoyl-L- and N-3-hydroxy- decanoyl-L-homoserine lactones on biofilm formation in Aliivibrio salmonicida
Khider, Miriam; Hansen, Hilde; Hjerde, Erik; Johansen, Jostein A; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-04-30)<i>Background</i>: Bacterial communication through quorum sensing (QS) systems has been reported to be important in coordinating several traits such as biofilm formation. In <i>Aliivibrio salmonicida</i> two QS systems the LuxI/R and AinS/R, have been shown to be responsible for the production of eight acyl-homoserine lactones (AHLs) in a cell density dependent manner. We have previously ... -
High natural PHA production from acetate in Cobetia sp. MC34 and Cobetia marina DSM 4741T and in silico analyses of the genus specific PhaC2 polymerase variant
Christensen, Mikkel; Jablonski, Piotr; Altermark, Bjørn; Irgum, Knut; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-20)Background: Several members of the bacterial Halomonadacea family are natural producers of polyhydroxyalkanoates (PHA), which are promising materials for use as biodegradable bioplastics. Type-strain species of Cobetia are designated PHA positive, and recent studies have demonstrated relatively high PHA production for a few strains within this genus. Industrially relevant PHA producers may therefore ... -
High natural PHA production from acetate in Cobetia sp. MC34 and Cobetia marina DSM 4741T and in silico analyses of the genus specific PhaC2 polymerase variant
Christensen, Mikkel; Jablonski, Piotr; Altermark, Bjørn; Irgum, Knut; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-20)<b>Background</b> <p>Several members of the bacterial <i>Halomonadacea</i> family are natural producers of polyhydroxyalkanoates (PHA), which are promising materials for use as biodegradable bioplastics. Type-strain species of <i>Cobetia</i> are designated PHA positive, and recent studies have demonstrated relatively high PHA production for a few strains within this genus. Industrially relevant ... -
The immediate global responses of Aliivibrio salmonicida to iron limitations
Thode, Sunniva Katharina; Kahlke, Tim; Robertsen, Espen Mikal; Hansen, Hilde; Haugen, Peik (Journal article; Tidsskriftartikkel, 2015-02-04)<i>Background</i>: Iron is an essential micronutrient for all living organisms, and virulence and sequestration of iron in pathogenic bacteria are believed to be correlated. As a defence mechanism, potential hosts therefore keep the level of free iron inside the body to a minimum. In general, iron metabolism is well studied for some bacteria (mostly human or animal pathogens). However, this area ... -
PHI-base update : additions to the pathogen-host interaction database
Winnenburg, Rainer; Hansen, Hilde; Urban, Martin; Kohler, Jacob Tilman; Beacham, Andrew; Baldwin, Thomas K; Holland, Sabrina; Lindeberg, Magdalen; Rawlings, Christopher; Hammond-Kosack, Kim E (Journal article; Tidsskriftartikkel; Peer reviewed, 2008) -
Presence of acyl-homoserine lactones in 57 members of the Vibrionaceae family
Purohit, Amit Anand; Johansen, Jostein a; Hansen, Hilde; Leiros, Hanna-Kirsti S.; Kashulin, Alexander; Karlsen, Christian; Smalås, Arne O.; Haugen, Peik; Willassen, Nils Peder (Journal article; Tidsskriftartikkel; Peer reviewed, 2013-05-31)Aims: The aim of this study was to use a sensitive method to screen and quantify 57 Vibrionaceae strains for the production of acyl-homoserine lactones (AHLs) and map the resulting AHL profiles onto a host phylogeny.<p> <p>Methods and Results: We used a high-performance liquid chromatography– tandem mass spectrometry (HPLC-MS/MS) protocol to measure AHLs in spent media after bacterial growth. ... -
Quorum Sensing Controls the CRISPR and Type VI Secretion Systems in Aliivibrio wodanis 06/09/139
Maharajan, Amudha Deepalakshmi; Hjerde, Erik; Hansen, Hilde; Willassen, Nils P (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-02-22)For bacteria to thrive in an environment with competitors, phages and environmental cues, they use different strategies, including Type VI Secretion Systems (T6SSs) and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) to compete for space. Bacteria often use quorum sensing (QS), to coordinate their behavior as the cell density increases. Like other aliivibrios, Aliivibrio wodanis ... -
Quorum sensing in Aliivibrio wodanis 06/09/139 and its role in controlling various phenotypic traits
Maharajan, Amudha Deepalakshmi; Hansen, Hilde; Khider, Miriam; Willassen, Nils P (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-08-24)Background Quorum Sensing (QS) is a cell-to-cell communication system that bacteria utilize to adapt to the external environment by synthesizing and responding to signalling molecules called autoinducers. The psychrotrophic bacterium Aliivibrio wodanis 06/09/139, originally isolated from a winter ulcer of a reared Atlantic salmon, produces the autoinducer N-3-hydroxy-decanoyl-homoserine-lactone ... -
Towards high-throughput screening (HTS) of polyhydroxyalkanoate (PHA) production via Fourier transform infrared (FTIR) spectroscopy of Halomonas sp. R5-57 and Pseudomonas sp. MR4-99
Christensen, Mikkel; Chiciudean, Iulia; Jablonski, Piotr; Tanase, Ana Maria; Shapaval, Volha; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-08)High-throughput screening (HTS) methods for characterization of microbial production of polyhydroxyalkanoates (PHA) are currently under investigated, despite the advent of such systems in related fields. In this study, phenotypic microarray by Biolog PM1 screening of Halomonas sp. R5-57 and Pseudomonas sp. MR4-99 identified 49 and 54 carbon substrates to be metabolized by these bacteria, respectively. ... -
Towards high-throughput screening (HTS) of polyhydroxyalkanoate (PHA) production via Fourier transform infrared (FTIR) spectroscopy of Halomonas sp. R5-57 and Pseudomonas sp. MR4-99
Christensen, Mikkel; Chiciudean, Iulia; Jablonski, Piotr; Tănase, Ana-Maria; Shapaval, Volha; Hansen, Hilde (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-03-08) -
A unique class I polyhydroxyalkanoate synthase (PhaC) from Brevundimonas sp. KH11J01 exists as a functional trimer: A comparative study with PhaC from Cupriavidus necator H16
Assefa, Netsanet Gizaw; Hansen, Hilde; Altermark, Bjørn (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-06)Polyhydroxyalkanoates (PHAs) are natural biodegradable polyesters that are produced by numerous prokaryotic microorganisms primarily as a carbon- and energy reserve. The PhaC enzyme catalyzes the last step in the PHA biosynthesis pathway and synthesizes PHA polymers from hydroxyalkanoic acids. A type I PhaC from a PHAproducing marine bacterium Brevundimonas sp. KH11J01 (BrPhaC) was identified, ...