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Małachowicz M, Krasnov A, Wenne R. Diverse Transcriptome Responses to Salinity Change in Atlantic Cod Subpopulations. Cells 2023; 12:2760. [PMID: 38067188 PMCID: PMC10706248 DOI: 10.3390/cells12232760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/25/2023] [Accepted: 11/29/2023] [Indexed: 12/18/2023] Open
Abstract
Adaptation to environmental variation caused by global climate change is a significant aspect of fisheries management and ecology. A reduction in ocean salinity is visible in near-shore areas, especially in the Baltic Sea, where it is affecting the Atlantic cod population. Cod is one of the most significant teleost species, with high ecological and economical value worldwide. The population of cod in the Baltic Sea has been traditionally divided into two subpopulations (western and eastern) existing in higher- and lower-salinity waters, respectively. In recent decades, both Baltic cod subpopulations have declined massively. One of the reasons for the poor condition of cod in the Baltic Sea is environmental factors, including salinity. Thus, in this study, an oligonucleotide microarray was applied to explore differences between Baltic cod subpopulations in response to salinity fluctuations. For this purpose, an exposure experiment was conducted consisting of salinity elevation and reduction, and gene expression was measured in gill tissue. We found 400 differentially expressed genes (DEGs) involved in the immune response, metabolism, programmed cell death, cytoskeleton, and extracellular matrix that showed a subpopulation-dependent pattern. These findings indicate that osmoregulation in Baltic cod is a complex process, and that western and eastern Baltic cod subpopulations respond differently to salinity changes.
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Affiliation(s)
- Magdalena Małachowicz
- Institute of Oceanology Polish Academy of Sciences, Powstanców Warszawy 55, 81-712 Sopot, Poland;
| | - Aleksei Krasnov
- Department of Fish Health, Nofima—Norwegian Institute of Food, Fisheries and Aquaculture Research, Osloveien 1, NO-1431 Ås, Norway;
| | - Roman Wenne
- Institute of Oceanology Polish Academy of Sciences, Powstanców Warszawy 55, 81-712 Sopot, Poland;
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2
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Skåne A, Edvardsen PK, Cordara G, Loose JSM, Leitl KD, Krengel U, Sørum H, Askarian F, Vaaje-Kolstad G. Chitinolytic enzymes contribute to the pathogenicity of Aliivibrio salmonicida LFI1238 in the invasive phase of cold-water vibriosis. BMC Microbiol 2022; 22:194. [PMID: 35941540 PMCID: PMC9361615 DOI: 10.1186/s12866-022-02590-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/27/2022] [Indexed: 11/26/2022] Open
Abstract
Background Aliivibrio salmonicida is the causative agent of cold-water vibriosis in salmonids (Oncorhynchus mykiss and Salmo salar L.) and gadidae (Gadus morhua L.). Virulence-associated factors that are essential for the full spectrum of A. salmonicida pathogenicity are largely unknown. Chitin-active lytic polysaccharide monooxygenases (LPMOs) have been indicated to play roles in both chitin degradation and virulence in a variety of pathogenic bacteria but are largely unexplored in this context. Results In the present study we investigated the role of LPMOs in the pathogenicity of A. salmonicida LFI238 in Atlantic salmon (Salmo salar L.). In vivo challenge experiments using isogenic deletion mutants of the two LPMOs encoding genes AsLPMO10A and AsLPMO10B, showed that both LPMOs, and in particular AsLPMO10B, were important in the invasive phase of cold-water vibriosis. Crystallographic analysis of the AsLPMO10B AA10 LPMO domain (to 1.4 Å resolution) revealed high structural similarity to viral fusolin, an LPMO known to enhance the virulence of insecticidal agents. Finally, exposure to Atlantic salmon serum resulted in substantial proteome re-organization of the A. salmonicida LPMO deletion variants compared to the wild type strain, indicating the struggle of the bacterium to adapt to the host immune components in the absence of the LPMOs. Conclusion The present study consolidates the role of LPMOs in virulence and demonstrates that such enzymes may have more than one function.
Supplementary Information The online version contains supplementary material available at 10.1186/s12866-022-02590-2.
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Affiliation(s)
- Anna Skåne
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Per Kristian Edvardsen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Gabriele Cordara
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, NO-0315, Oslo, Norway
| | - Jennifer Sarah Maria Loose
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway
| | - Kira Daryl Leitl
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, NO-0315, Oslo, Norway
| | - Ute Krengel
- Department of Chemistry, University of Oslo, Blindern, P.O. Box 1033, NO-0315, Oslo, Norway
| | - Henning Sørum
- Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Fatemeh Askarian
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, School of Medicine, UC San Diego, La Jolla, San Diego, CA, USA.
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), Ås, Norway.
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Domingues Vieira B, Niero H, de Felício R, Giolo Alves LF, Freitas Bazzano C, Sigrist R, Costa Furtado L, Felix Persinoti G, Veras Costa-Lotufo L, Barretto Barbosa Trivella D. Production of Epoxyketone Peptide-Based Proteasome Inhibitors by Streptomyces sp. BRA-346: Regulation and Biosynthesis. Front Microbiol 2022; 13:786008. [PMID: 35401454 PMCID: PMC8988807 DOI: 10.3389/fmicb.2022.786008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/31/2022] [Indexed: 11/13/2022] Open
Abstract
Streptomyces sp. BRA-346 is an Actinobacteria isolated from the Brazilian endemic tunicate Euherdmania sp. We have reported that this strain produces epoxyketone peptides, as dihydroeponemycin (DHE) and structurally related analogs. This cocktail of epoxyketone peptides inhibits the proteasome chymotrypsin-like activity and shows high cytotoxicity to glioma cells. However, low yields and poor reproducibility of epoxyketone peptides production by BRA-346 under laboratory cultivation have limited the isolation of epoxyketone peptides for additional studies. Here, we evaluated several cultivation methods using different culture media and chemical elicitors to increase the repertoire of peptide epoxyketone production by this bacterium. Furthermore, BRA-346 genome was sequenced, revealing its broad genetic potential, which is mostly hidden under laboratory conditions. By using specific growth conditions, we were able to evidence different classes of secondary metabolites produced by BRA-346. In addition, by combining genome mining with untargeted metabolomics, we could link the metabolites produced by BRA-346 to its genetic capacity and potential regulators. A single biosynthetic gene cluster (BGC) was related to the production of the target epoxyketone peptides by BRA-346. The candidate BGC displays conserved biosynthetic enzymes with the reported eponemycin (EPN) and TMC-86A (TMC) BGCs. The core of the putative epoxyketone peptide BGC (ORFs A-L), in which ORF A is a LuxR-like transcription factor, was cloned into a heterologous host. The recombinant organism was capable to produce TMC and EPN natural products, along with the biosynthetic intermediates DH-TMC and DHE, and additional congeners. A phylogenetic analysis of the epn/tmc BGC revealed related BGCs in public databases. Most of them carry a proteasome beta-subunit, however, lacking an assigned specialized metabolite. The retrieved BGCs also display a diversity of regulatory genes and TTA codons, indicating tight regulation of this BGC at the transcription and translational levels. These results demonstrate the plasticity of the epn/tmc BGC of BRA-346 in producing epoxyketone peptides and the feasibility of their production in a heterologous host. This work also highlights the capacity of BRA-346 to tightly regulate its secondary metabolism and shed light on how to awake silent gene clusters of Streptomyces sp. BRA-346 to allow the production of pharmacologically important biosynthetic products.
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Affiliation(s)
- Bruna Domingues Vieira
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Faculty of Pharmaceutical Sciences (FCF), University of Campinas (UNICAMP), Campinas, Brazil
| | - Henrique Niero
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Faculty of Pharmaceutical Sciences (FCF), University of Campinas (UNICAMP), Campinas, Brazil
| | - Rafael de Felício
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Luiz Fernando Giolo Alves
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Cristina Freitas Bazzano
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- Institute of Computing (IC), University of Campinas (UNICAMP), Campinas, Brazil
| | - Renata Sigrist
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Luciana Costa Furtado
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Gabriela Felix Persinoti
- Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
| | - Leticia Veras Costa-Lotufo
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Daniela Barretto Barbosa Trivella
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil
- *Correspondence: Daniela Barretto Barbosa Trivella,
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Tepavčević J, Yarrington K, Fung B, Lin X, Visick KL. sRNA chaperone Hfq controls bioluminescence and other phenotypes through Qrr1-dependent and -independent mechanisms in Vibrio fischeri. Gene X 2022; 809:146048. [PMID: 34756963 PMCID: PMC8673744 DOI: 10.1016/j.gene.2021.146048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 10/26/2021] [Indexed: 02/01/2023] Open
Abstract
Colonization of the squid Euprymna scolopes by the bacterium Vibrio fischeri depends on bacterial biofilm formation, motility, and bioluminescence. Previous work has demonstrated an inhibitory role for the small RNA (sRNA) Qrr1 in quorum-induced bioluminescence of V. fischeri, but the contribution of the corresponding sRNA chaperone, Hfq, was not examined. We thus hypothesized that V. fischeri Hfq similarly functions to inhibit bacterial bioluminescence as well as regulate other key steps of symbiosis, including bacterial biofilm formation and motility. Surprisingly, deletion of hfq increased luminescence of V. fischeri beyond what was observed for the loss of qrr1 sRNA. Epistasis experiments revealed that, while Hfq contributes to the Qrr1-dependent regulation of light production, it also functions independently of Qrr1 and its downstream target, LitR. This Hfq-dependent, Qrr1-independent regulation of bioluminescence is also independent of the major repressor of light production in V. fischeri, ArcA. We further determined that Hfq is required for full motility of V. fischeri in a mechanism that partially depends on the Qrr1/LitR regulators. Finally, Hfq also appears to function in the control of biofilm formation: loss of Hfq delayed the timing and diminished the extent of wrinkled colony development, but did not eliminate the production of SYP-polysaccharide-dependent cohesive colonies. Furthermore, loss of Hfq enhanced production of cellulose and resulted in increased Congo red binding. Together, these findings point to Hfq as an important regulator of multiple phenotypes relevant to symbiosis between V. fischeri and its squid host.
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Affiliation(s)
- Jovanka Tepavčević
- Department of Biology, Wheaton College, Wheaton, Illinois, USA,Corresponding author
| | - Kaiti Yarrington
- Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Brittany Fung
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois
| | - Xijin Lin
- Department of Biology, Wheaton College, Wheaton, Illinois, USA
| | - Karen L. Visick
- Department of Microbiology and Immunology, Loyola University Chicago, Maywood, Illinois
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Bazhenov S, Melkina O, Fomin V, Scheglova E, Krasnik P, Khrulnova S, Zavilgelsky G, Manukhov I. LitR directly upregulates autoinducer synthesis and luminescence in Aliivibrio logei. PeerJ 2021; 9:e12030. [PMID: 34616599 PMCID: PMC8462370 DOI: 10.7717/peerj.12030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/30/2021] [Indexed: 11/23/2022] Open
Abstract
LitR is a master-regulator of transcription in the ainS/R and luxS/PQ quorum sensing (QS) systems of bacteria from Vibrio and Aliivibrio genera. Here, we for the first time directly investigated the influence of LitR on gene expression in the luxI/R QS system of psychrophilic bacteria Aliivibrio logei. Investigated promoters were fused with Photorhabdus luminescens luxCDABE reporter genes cassette in a heterological system of Escherichia coli cells, litR A. logei was introduced into the cells under control of Plac promoter. LitR has been shown to upregulate genes of autoinducer synthase (luxI), luciferase and reductase (luxCDABE), and this effect doesn’t depend on presence of luxR gene. To a much lesser degree, LitR induces luxR1, but not the luxR2 — the main luxI/R regulator. Enhanced litR expression leads to an increase in a LuxI-autoinducer synthesis and a subsequent LuxR-mediated activation of the luxI/R QS system. Effect of LitR on luxI transcription depends on lux-box sequence in luxI promoter even in absence of luxR (lux-box is binding site of LuxR). The last finding indicates a direct interaction of LitR with the promoter in the lux-box region. Investigation of the effect of LitR A. logei on luxI/R QS systems of mesophilic Aliivibrio fischeri and psychrophilic Aliivibrio salmonicida showed direct luxR-independent upregulation of luxI and luxCDABE genes. To a lesser degree, it induces luxR A. fischeri and luxR1 A. salmonicida. Therefore, we assume that the main role of LitR in cross-interaction of these three QS systems is stimulating the expression of luxI.
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Affiliation(s)
- Sergey Bazhenov
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Higher School of Economics, Moscow, Russia
| | - Olga Melkina
- State Research Institute of Genetics and Selection of Industrial Microorganisms of the National Research Center "Kurchatov Institute", Moscow, Russia.,State Research Institute of Genetics and Selection of Industrial Microorganisms of the National Research Centre "Kurchatov Institute", Kurchatov Genomic Center, Moscow, Russia
| | - Vadim Fomin
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Ekaterina Scheglova
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Pavel Krasnik
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Svetlana Khrulnova
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,National Research Center for Hematology, Moscow, Russia
| | - Gennadii Zavilgelsky
- State Research Institute of Genetics and Selection of Industrial Microorganisms of the National Research Center "Kurchatov Institute", Moscow, Russia
| | - Ilya Manukhov
- Laboratory for Molecular Genetics, Moscow Institute of Physics and Technology, Dolgoprudny, Russia.,Higher School of Economics, Moscow, Russia.,State Research Institute of Genetics and Selection of Industrial Microorganisms of the National Research Center "Kurchatov Institute", Moscow, Russia
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6
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Maharajan AD, Hansen H, Khider M, Willassen NP. Quorum sensing in Aliivibrio wodanis 06/09/139 and its role in controlling various phenotypic traits. PeerJ 2021; 9:e11980. [PMID: 34513327 PMCID: PMC8395575 DOI: 10.7717/peerj.11980] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/25/2021] [Indexed: 11/20/2022] Open
Abstract
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 (3OHC10-HSL) and encodes the QS systems AinS/R and LuxS/PQ, and the master regulator LitR. However, the role of QS in this bacterium has not been investigated yet. Results In the present work we show that 3OHC10-HSL production is cell density and temperature-dependent in A. wodanis 06/09/139 with the highest production occurring at a low temperature (6 °C). Gene inactivation demonstrates that AinS is responsible for 3OHC10-HSL production and positively regulated by LitR. Inactivation of ainS and litR further show that QS is involved in the regulation of growth, motility, hemolysis, protease activity and siderophore production. Of these QS regulated activities, only the protease activity was found to be independent of LitR. Lastly, supernatants harvested from the wild type and the ΔainS and ΔlitR mutants at high cell densities show that inactivation of QS leads to a decreased cytopathogenic effect (CPE) in a cell culture assay, and strongest attenuation of the CPE was observed with supernatants harvested from the ΔlitR mutant. Conclusion A. wodanis 06/09/139 use QS to regulate a number of activities that may prove important for host colonization or interactions. The temperature of 6 °C that is in the temperature range at which winter ulcer occurs, plays a role in AHL production and development of CPE on a Chinook Salmon Embryo (CHSE) cell line.
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Affiliation(s)
- Amudha Deepalakshmi Maharajan
- Norwegian Structural Biology Center and The Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Hilde Hansen
- Norwegian Structural Biology Center and The Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Miriam Khider
- Department of Public Health and Nursing, Faculty of Medicine and Health Sciences, NTNU-Norwegian University of Science and Technology, Trondheim, Norway
| | - Nils Peder Willassen
- Norwegian Structural Biology Center and The Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway.,Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
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7
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The fish pathogen Aliivibrio salmonicida LFI1238 can degrade and metabolize chitin despite major gene loss in the chitinolytic pathway. Appl Environ Microbiol 2021; 87:e0052921. [PMID: 34319813 DOI: 10.1128/aem.00529-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The fish pathogen Aliivibrio (Vibrio) salmonicida LFI1238 is thought to be incapable of utilizing chitin as a nutrient source since approximately half of the genes representing the chitinolytic pathway are disrupted by insertion sequences. In the present study, we combined a broad set of analytical methods to investigate this hypothesis. Cultivation studies revealed that Al. salmonicida grew efficiently on N-acetylglucosamine (GlcNAc) and chitobiose ((GlcNAc)2), the primary soluble products resulting from enzymatic chitin hydrolysis. The bacterium was also able to grow on chitin particles, albeit at a lower rate compared to the soluble substrates. The genome of the bacterium contains five disrupted chitinase genes (pseudogenes) and three intact genes encoding a glycoside hydrolase family 18 (GH18) chitinase and two auxiliary activity family 10 (AA10) lytic polysaccharide monooxygenases (LPMOs). Biochemical characterization showed that the chitinase and LPMOs were able to depolymerize both α- and β-chitin to (GlcNAc)2 and oxidized chitooligosaccharides, respectively. Notably, the chitinase displayed up to 50-fold lower activity compared to other well-studied chitinases. Deletion of the genes encoding the intact chitinolytic enzymes showed that the chitinase was important for growth on β-chitin, whereas the LPMO gene-deletion variants only showed minor growth defects on this substrate. Finally, proteomic analysis of Al. salmonicida LFI1238 growth on β-chitin showed expression of all three chitinolytic enzymes, and intriguingly also three of the disrupted chitinases. In conclusion, our results show that Al. salmonicida LFI1238 can utilize chitin as a nutrient source and that the GH18 chitinase and the two LPMOs are needed for this ability. IMPORTANCE The ability to utilize chitin as a source of nutrients is important for the survival and spread of marine microbial pathogens in the environment. One such pathogen is Aliivibrio (Vibrio) salmonicida, the causative agent of cold water vibriosis. Due to extensive gene decay, many key enzymes in the chitinolytic pathway have been disrupted, putatively rendering this bacterium incapable of chitin degradation and utilization. In the present study we demonstrate that Al. salmonicida can degrade and metabolize chitin, the most abundant biopolymer in the ocean. Our findings shed new light on the environmental adaption of this fish pathogen.
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Ghanei-Motlagh R, Mohammadian T, Gharibi D, Menanteau-Ledouble S, Mahmoudi E, Khosravi M, Zarea M, El-Matbouli M. Quorum Quenching Properties and Probiotic Potentials of Intestinal Associated Bacteria in Asian Sea Bass Lates calcarifer. Mar Drugs 2019; 18:md18010023. [PMID: 31888034 PMCID: PMC7024293 DOI: 10.3390/md18010023] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/20/2019] [Accepted: 12/23/2019] [Indexed: 02/07/2023] Open
Abstract
Quorum quenching (QQ), the enzymatic degradation of N-acyl homoserine lactones (AHLs), has been suggested as a promising strategy to control bacterial diseases. In this study, 10 AHL-degrading bacteria isolated from the intestine of barramundi were identified by 16S rDNA sequencing. They were able to degrade both short and long-chain AHLs associated with several pathogenic Vibrio species (spp.) in fish, including N-[(RS)-3-Hydroxybutyryl]-l-homoserine lactone (3-oh-C4-HSL), N-Hexanoyl-l-homoserine lactone (C6-HSL), N-(β-Ketocaproyl)-l-homoserine lactone (3-oxo-C6-HSL), N-(3-Oxodecanoyl)-l-homoserine lactone (3-oxo-C10-HSL), N-(3-Oxotetradecanoyl)-l-homoserine lactone (3-oxo-C14-HSL). Five QQ isolates (QQIs) belonging to the Bacillus and Shewanella genera, showed high capacity to degrade both synthetic AHLs as well as natural AHLs produced by Vibrio harveyi and Vibrio alginolyticus using the well-diffusion method and thin-layer chromatography (TLC). The genes responsible for QQ activity, including aiiA, ytnP, and aaC were also detected. Analysis of the amino acid sequences from the predicted lactonases revealed the presence of the conserved motif HxHxDH. The selected isolates were further characterized in terms of their probiotic potentials in vitro. Based on our scoring system, Bacillus thuringiensis QQ1 and Bacillus cereus QQ2 exhibited suitable probiotic characteristics, including the production of spore and exoenzymes, resistance to bile salts and pH, high potential to adhere on mucus, appropriate growth abilities, safety to barramundi, and sensitivity to antibiotics. These isolates, therefore, constitute new QQ probiotics that could be used to control vibriosis in Lates calcalifer.
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Affiliation(s)
- Reza Ghanei-Motlagh
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria; (R.G.-M.); (M.E.-M.)
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz 61357-831351, Iran;
| | - Takavar Mohammadian
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz 61357-831351, Iran;
- Correspondence: (T.M.); (S.M.-L.)
| | - Darioush Gharibi
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz 61357-831351, Iran; (D.G.); (M.K.)
| | - Simon Menanteau-Ledouble
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria; (R.G.-M.); (M.E.-M.)
- Correspondence: (T.M.); (S.M.-L.)
| | - Esmaeil Mahmoudi
- Department of Plant Protection, Faculty of Agriculture, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan 158-81595, Iran;
| | - Mohammad Khosravi
- Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz 61357-831351, Iran; (D.G.); (M.K.)
| | - Mojtaba Zarea
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz 61357-831351, Iran;
| | - Mansour El-Matbouli
- Clinical Division of Fish Medicine, University of Veterinary Medicine, 1210 Vienna, Austria; (R.G.-M.); (M.E.-M.)
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Malachowicz M, Wenne R. Microarray analysis of gene expression of Atlantic cod from different Baltic Sea regions: Adaptation to salinity. Mar Genomics 2019. [DOI: 10.1016/j.margen.2019.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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10
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Söderberg JJ, Grgic M, Hjerde E, Haugen P. Aliivibrio wodanis as a production host: development of genetic tools for expression of cold-active enzymes. Microb Cell Fact 2019; 18:197. [PMID: 31711487 PMCID: PMC6844050 DOI: 10.1186/s12934-019-1247-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/31/2019] [Indexed: 01/16/2023] Open
Abstract
Background Heterologous production of cold-adapted proteins currently represents one of the greatest bottlenecks in the ongoing bioprospecting efforts to find new enzymes from low-temperature environments, such as, the polar oceans that represent essentially untapped resources in this respect. In mesophilic expression hosts such as Escherichia coli, cold-adapted enzymes often form inactive aggregates. Therefore it is necessary to develop new low-temperature expression systems, including identification of new host organisms and complementary genetic tools. Psychrophilic bacteria, including Pseudoalteromonas haloplanktis, Shewanella and Rhodococcus erythropolis have all been explored as candidates for such applications. However to date none of these have found widespread use as efficient expression systems, or are commercially available. In the present work we explored the use of the sub-Arctic bacterium Aliivibrio wodanis as a potential host for heterologous expression of cold-active enzymes. Results We tested 12 bacterial strains, as well as available vectors, promoters and reporter systems. We used RNA-sequencing to determine the most highly expressed genes and their intrinsic promoters in A. wodanis. In addition we examined a novel 5′-fusion to stimulate protein production and solubility. Finally we tested production of a set of “difficult-to-produce” enzymes originating from various bacteria and one Archaea. Our results show that cold-adapted enzymes can be produced in soluble and active form, even in cases when protein production failed in E. coli due to the formation of inclusion bodies. Moreover, we identified a 60-bp/20-aa fragment from the 5′-end of the AW0309160_00174 gene that stimulates expression of Green Fluorescent Protein and improves production of cold-active enzymes when used as a 5′-fusion. A 25-aa peptide from the same protein enhanced secretion of a 25-aa-sfGFP fusion. Conclusions Our results indicate the use of A. wodanis and associated genetic tools for low-temperature protein production and indicate that A. wodanis represents an interesting platform for further development of a protein production system that can promote further cold-enzyme discoveries.
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Affiliation(s)
- Jenny Johansson Söderberg
- Department of Chemistry and Center for Bioinformatics (SfB) and The Norwegian Structural Biology Centre (NorStruct), Faculty of Science and Technology, UiT -The Arctic University of Norway, 9037, Tromsø, Norway
| | - Miriam Grgic
- Department of Chemistry and Center for Bioinformatics (SfB) and The Norwegian Structural Biology Centre (NorStruct), Faculty of Science and Technology, UiT -The Arctic University of Norway, 9037, Tromsø, Norway
| | - Erik Hjerde
- Department of Chemistry and Center for Bioinformatics (SfB) and The Norwegian Structural Biology Centre (NorStruct), Faculty of Science and Technology, UiT -The Arctic University of Norway, 9037, Tromsø, Norway
| | - Peik Haugen
- Department of Chemistry and Center for Bioinformatics (SfB) and The Norwegian Structural Biology Centre (NorStruct), Faculty of Science and Technology, UiT -The Arctic University of Norway, 9037, Tromsø, Norway.
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11
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Khider M, Hansen H, Hjerde E, Johansen JA, Willassen NP. 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. PeerJ 2019; 7:e6845. [PMID: 31106062 PMCID: PMC6499059 DOI: 10.7717/peerj.6845] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 03/18/2019] [Indexed: 01/12/2023] Open
Abstract
Background Bacterial communication through quorum sensing (QS) systems has been reported to be important in coordinating several traits such as biofilm formation. In Aliivibrio salmonicida 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 demonstrated that inactivation of LitR, the master regulator of the QS system resulted in biofilm formation, similar to the biofilm formed by the AHL deficient mutant ΔainSluxI−. In this study, we aimed to investigate the global gene expression patterns of luxI and ainS autoinducer synthases mutants using transcriptomic profiling. In addition, we examined the influence of the different AHLs on biofilm formation. Results The transcriptome profiling of ΔainS and luxI− mutants allowed us to identify genes and gene clusters regulated by QS in A. salmonicida. Relative to the wild type, the ΔainS and luxI− mutants revealed 29 and 500 differentially expressed genes (DEGs), respectively. The functional analysis demonstrated that the most pronounced DEGs were involved in bacterial motility and chemotaxis, exopolysaccharide production, and surface structures related to adhesion. Inactivation of luxI, but not ainS genes resulted in wrinkled colony morphology. While inactivation of both genes (ΔainSluxI−) resulted in strains able to form wrinkled colonies and mushroom structured biofilm. Moreover, when the ΔainSluxI− mutant was supplemented with N-3-oxo-hexanoyl-L-homoserine lactone (3OC6-HSL) or N-3-hydroxy-decanoyl-L-homoserine lactone (3OHC10-HSL), the biofilm did not develop. We also show that LuxI is needed for motility and for repression of EPS production, where repression of EPS is likely operated through the RpoQ-sigma factor. Conclusion These findings imply that the LuxI and AinS autoinducer synthases play a critical role in the regulation of biofilm formation, EPS production, and motility.
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Affiliation(s)
- Miriam Khider
- Norwegian Structural Biology Centre, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Hilde Hansen
- Norwegian Structural Biology Centre, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Erik Hjerde
- Norwegian Structural Biology Centre, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway.,Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Jostein A Johansen
- Norwegian Structural Biology Centre, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
| | - Nils Peder Willassen
- Norwegian Structural Biology Centre, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway.,Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT-The Arctic University of Norway, Tromsø, Norway
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12
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Noor NM, Defoirdt T, Alipiah N, Karim M, Daud H, Natrah I. Quorum sensing is required for full virulence of Vibrio campbellii towards tiger grouper (Epinephelus fuscoguttatus) larvae. JOURNAL OF FISH DISEASES 2019; 42:489-495. [PMID: 30742313 DOI: 10.1111/jfd.12946] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 06/09/2023]
Abstract
The link between quorum sensing in Vibrio campbellii and its virulence towards tiger grouper (Epinephelus fuscoguttatus) was investigated using V. campbellii wild type and quorum-sensing mutants with inactive quorum sensing or constitutively maximal quorum-sensing activity, and signal molecule synthase mutants. The results showed that wild-type V. campbellii is pathogenic to grouper larvae, causing more than 50% mortality after 4 days of challenge. Furthermore, the mortality of larvae challenged with the mutant with maximally active quorum sensing was significantly higher than that of larvae challenged with the wild type, whereas a higher survival was observed in the larvae challenged to the mutant with a completely inactive quorum-sensing system. Grouper larvae challenged with either the signal molecule synthase triple mutant, the harveyi autoinducer-1 (HAI-1) synthase mutant and the autoinducer-2 (AI-2) synthase mutant showed higher survival than larvae challenged with the wild type. In contrast, larvae challenged with the cholerae autoinducer-1 (CAI-1) synthase mutant showed high mortality. This indicates that HAI-1 and AI-2, but not CAI-1, are required for full virulence of V. campbellii towards grouper larvae. Our data suggest that quorum-sensing inhibition could be an effective strategy to control V. campbellii infections in tiger grouper.
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Affiliation(s)
- Noorashikin Md Noor
- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Tom Defoirdt
- Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Norfarrah Alipiah
- Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor
| | - Murni Karim
- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor
| | - Hassan Daud
- Laboratory of Marine Biotechnology, Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor
| | - Ikhsan Natrah
- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Laboratory of Sustainable Aquaculture, International Institute of Aquaculture and Aquatic Sciences, Universiti Putra Malaysia, Serdang, Selangor
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13
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Khider M, Hjerde E, Hansen H, Willassen NP. Differential expression profiling of ΔlitR and ΔrpoQ mutants reveals insight into QS regulation of motility, adhesion and biofilm formation in Aliivibrio salmonicida. BMC Genomics 2019; 20:220. [PMID: 30876404 PMCID: PMC6420764 DOI: 10.1186/s12864-019-5594-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 03/11/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND 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. Aliivibrio salmonicida, the causative agent of cold-water vibrosis in marine aquacultures, uses QS to regulate several activities such as motility, biofilm formation, adhesion and rugose colony morphology. However, little is known about either genes or detailed mechanisms involved in the regulation of these phenotypes. RESULTS Differential expression profiling allowed us to define the genes involved in controlling phenotypes related to QS in A. salmonicida LFI1238. RNA sequencing data revealed that the number of expressed genes in A. salmonicida, ΔlitR and ΔrpoQ mutants were significantly altered due to changes in cell density. These included genes that were distributed among the 21 functional groups, mainly presented in cell envelope, cell processes, extrachromosomal/foreign DNA and transport-binding proteins functional groups. The comparative transcriptome of A. salmonicida wild-type at high cell density relative to low cell density revealed 1013 genes to be either up- or downregulated. Thirty-six downregulated genes were gene clusters encoding biosynthesis of the flagellar and chemotaxis genes. Additionally we identified significant expression for genes involved in acyl homoserine lactone (AHL) synthesis, adhesion and early colonization. The transcriptome profile of ΔrpoQ compared to the wild-type revealed 384 differensially expressed genes (DEGs) that allowed us to assign genes involved in regulating motility, adhesion and colony rugosity. Indicating the importance of RpoQ in controlling several QS related activities. Furthermore, the comparison of the transcriptome profiles of ΔlitR and ΔrpoQ mutants, exposed numerous overlapping DEGs that were essential for motility, exopolysaccharide production via syp operon and genes associated with tad operon. CONCLUSION Our findings indicate previously unexplained functional roles for LitR and RpoQ in regulation of different phenotypes related to QS. Our transcriptome data provide a better understanding of the regulation cascade of motility, wrinkling colony morphology and biofilm formation and will offer a major source for further research and analysis on this important field.
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Affiliation(s)
- Miriam Khider
- Norwegian Structural Biology Centre, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway.
| | - Erik Hjerde
- Norwegian Structural Biology Centre, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway.,Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway
| | - Hilde Hansen
- Norwegian Structural Biology Centre, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway
| | - Nils Peder Willassen
- Norwegian Structural Biology Centre, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway. .,Centre for Bioinformatics, Department of Chemistry, Faculty of Science and Technology, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway.
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14
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Martín-Rodríguez AJ, Álvarez-Méndez SJ, Overå C, Baruah K, Lourenço TM, Norouzitallab P, Bossier P, Martín VS, Fernández JJ. The 9 H-Fluoren Vinyl Ether Derivative SAM461 Inhibits Bacterial Luciferase Activity and Protects Artemia franciscana From Luminescent Vibriosis. Front Cell Infect Microbiol 2018; 8:368. [PMID: 30467537 PMCID: PMC6236115 DOI: 10.3389/fcimb.2018.00368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 10/03/2018] [Indexed: 11/13/2022] Open
Abstract
Vibrio campbellii is a major pathogen in aquaculture. It is a causative agent of the so-called “luminescent vibriosis,” a life-threatening condition caused by bioluminescent Vibrio spp. that often involves mass mortality of farmed shrimps. The emergence of multidrug resistant Vibrio strains raises a concern and poses a challenge for the treatment of this infection in the coming years. Inhibition of bacterial cell-to-cell communication or quorum sensing (QS) has been proposed as an alternative to antibiotic therapies. Aiming to identify novel QS disruptors, the 9H-fluroen-9yl vinyl ether derivative SAM461 was found to thwart V. campbellii bioluminescence, a QS-regulated phenotype. Phenotypic and gene expression analyses revealed, however, that the mode of action of SAM461 was unrelated to QS inhibition. Further evaluation with purified Vibrio fischeri and NanoLuc luciferases revealed enzymatic inhibition at micromolar concentrations. In silico analysis by molecular docking suggested binding of SAM461 in the active site cavities of both luciferase enzymes. Subsequent in vivo testing of SAM461 with gnotobiotic Artemia franciscana nauplii demonstrated naupliar protection against V. campbellii infection at low micromolar concentrations. Taken together, these findings suggest that suppression of luciferase activity could constitute a novel paradigm in the development of alternative anti-infective chemotherapies against luminescent vibriosis, and pave the ground for the chemical synthesis and biological characterization of derivatives with promising antimicrobial prospects.
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Affiliation(s)
- Alberto J Martín-Rodríguez
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain.,Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden
| | - Sergio J Álvarez-Méndez
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
| | - Caroline Overå
- Institute of Biophysics and Biophysical Chemistry, University of Regensburg, Regensburg, Germany
| | - Kartik Baruah
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.,Department of Animal Nutrition and Management, Faculty of Veterinary Medicine and Animal Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Tânia Margarida Lourenço
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Parisa Norouzitallab
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.,Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Ghent University, Ghent, Belgium
| | - Peter Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Víctor S Martín
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
| | - José J Fernández
- Instituto Universitario de Bio-Orgánica "Antonio González", Centro de Investigaciones Biomédicas de Canarias, Universidad de La Laguna, Tenerife, Spain
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15
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Aliivibrio salmonicida requires O-antigen for virulence in Atlantic salmon (Salmo salar L.). Microb Pathog 2018; 124:322-331. [DOI: 10.1016/j.micpath.2018.08.058] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 04/12/2018] [Accepted: 08/25/2018] [Indexed: 11/23/2022]
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16
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The alternative sigma factor RpoQ regulates colony morphology, biofilm formation and motility in the fish pathogen Aliivibrio salmonicida. BMC Microbiol 2018; 18:116. [PMID: 30208852 PMCID: PMC6134601 DOI: 10.1186/s12866-018-1258-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 09/04/2018] [Indexed: 02/04/2023] Open
Abstract
Background 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 Aliivibrio salmonicida, 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 rpoQ. RpoQ is an alternative sigma factor belonging to the sigma −70 family. Alternative sigma factors direct gene transcription in response to environmental signals. In this work we have studied the role of RpoQ in biofilm formation, colony morphology and motility of A. salmonicida LFI1238. Results The rpoQ gene in A. salmonicida LFI1238 was deleted using allelic exchange. We found that RpoQ is a strong repressor of rugose colony morphology and biofilm formation, and that it controls motility of the bacteria. We also show that overexpression of rpoQ in a ΔlitR mutant of A. salmonicida disrupts the biofilm produced by the ΔlitR mutant and decreases its motility, whereas rpoQ overexpression in the wild-type completely eliminates the motility. Conclusion The present work demonstrates that the RpoQ sigma factor is a novel regulatory component involved in modulating motility, colony morphology and biofilm formation in the fish pathogen A. salmonicida. The findings also confirm that RpoQ functions downstream of the QS master regulator LitR. However further studies are needed to elucidate how LitR and RpoQ work together in controlling phenotypes related to QS in A. salmonicida. Electronic supplementary material The online version of this article (10.1186/s12866-018-1258-9) contains supplementary material, which is available to authorized users.
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17
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Thode SK, Bækkedal C, Söderberg JJ, Hjerde E, Hansen H, Haugen P. Construction of a fur null mutant and RNA-sequencing provide deeper global understanding of the Aliivibrio salmonicida Fur regulon. PeerJ 2017; 5:e3461. [PMID: 28717590 PMCID: PMC5511505 DOI: 10.7717/peerj.3461] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 05/24/2017] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND 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 work, we used computational predictions and microarray to gain insights into Fur-regulation in Aliivibrio salmonicida, and have identified a number of genes and operons that appear to be under direct control of Fur. To provide a more accurate and deeper global understanding of the biological role of Fur we have now generated an A. salmonicida fur knock-out strain and used RNA-sequencing to compare gene expression between the wild-type and fur null mutant strains. RESULTS An A. salmonicida fur null mutant strain was constructed. Biological assays demonstrate that deletion of fur results in loss of fitness, with reduced growth rates, and reduced abilities to withstand low-iron conditions, and oxidative stress. When comparing expression levels in the wild-type and the fur null mutant we retrieved 296 differentially expressed genes distributed among 18 of 21 functional classes of genes. A gene cluster encoding biosynthesis of the siderophore bisucaberin represented the highest up-regulated genes in the fur null mutant. Other highly up-regulated genes all encode proteins important for iron acquisition. Potential targets for the RyhB sRNA was predicted from the list of down-regulated genes, and significant complementarities were found between RyhB and mRNAs of the fur, sodB, cysN and VSAL_I0422 genes. Other sRNAs with potential functions in iron homeostasis were identified. CONCLUSION The present work provides by far the most comprehensive and deepest understanding of the Fur regulon in A. salmonicida to date. Our data also contribute to a better understanding of how Fur plays a key role in iron homeostasis in bacteria in general, and help to show how Fur orchestrates iron uptake when iron levels are extremely low.
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Affiliation(s)
- Sunniva Katharina Thode
- Department of Chemistry and The Norwegian Structural Biology Centre, Faculty of Science and Technology, UiTThe Arctic University of Norway, Tromsø, Norway
| | - Cecilie Bækkedal
- Department of Chemistry and The Norwegian Structural Biology Centre, Faculty of Science and Technology, UiTThe Arctic University of Norway, Tromsø, Norway
| | - Jenny Johansson Söderberg
- Department of Chemistry and The Norwegian Structural Biology Centre, Faculty of Science and Technology, UiTThe Arctic University of Norway, Tromsø, Norway
| | - Erik Hjerde
- Department of Chemistry and The Norwegian Structural Biology Centre, Faculty of Science and Technology, UiTThe Arctic University of Norway, Tromsø, Norway
| | - Hilde Hansen
- Department of Chemistry and The Norwegian Structural Biology Centre, Faculty of Science and Technology, UiTThe Arctic University of Norway, Tromsø, Norway
| | - Peik Haugen
- Department of Chemistry and The Norwegian Structural Biology Centre, Faculty of Science and Technology, UiTThe Arctic University of Norway, Tromsø, Norway
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18
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Nørstebø SF, Paulshus E, Bjelland AM, Sørum H. A unique role of flagellar function in Aliivibrio salmonicida pathogenicity not related to bacterial motility in aquatic environments. Microb Pathog 2017; 109:263-273. [PMID: 28602841 DOI: 10.1016/j.micpath.2017.06.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/01/2017] [Accepted: 06/06/2017] [Indexed: 12/21/2022]
Abstract
Aliivibrio salmonicida is the causative agent of cold-water vibriosis, a septicemia of farmed salmonid fish. The mechanisms of disease are not well described, and few virulence factors have been identified. However, a requirement for motility in the pathogenesis has been reported. Al. salmonicida is motile by the means of lophotrichous polar flagella, consisting of multiple flagellin subunits that are expressed simultaneously. Here we show that flagellin subunit FlaA, but not FlaD, is of major importance for motility in Al. salmonicida. Deletion of flaA resulted in 62% reduction in motility, as well as a reduction in the fraction of flagellated cells and number of flagella per cell. Similarly, deletion of the gene encoding motor protein motA gave rise to an aflagellate phenotype and cessation of motility. Surprisingly, we found that Al. salmonicida does not require motility for invasion of Atlantic salmon. Nevertheless, in-frame deletion mutants defective of motA and flaA were less virulent in Atlantic salmon challenged by immersion, whereas an effect on virulence after i.p. challenge was only seen for the latter. Our results indicate a complex requirement for motility and/or flagellation in the pathogenesis of cold-water vibriosis, but the mechanisms involved remain unknown. We hypothesize that the differences in virulence observed after immersion and i.p. challenge are related to the immune response of the host.
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Affiliation(s)
- Simen Foyn Nørstebø
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033, Oslo, Norway.
| | - Erik Paulshus
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033, Oslo, Norway.
| | - Ane Mohn Bjelland
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033, Oslo, Norway.
| | - Henning Sørum
- Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033, Oslo, Norway.
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19
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Kashulin A, Seredkina N, Sørum H. Cold-water vibriosis. The current status of knowledge. JOURNAL OF FISH DISEASES 2017; 40:119-126. [PMID: 27072873 DOI: 10.1111/jfd.12465] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/08/2016] [Accepted: 01/10/2016] [Indexed: 06/05/2023]
Abstract
The current review for the first time summarizes the findings of the 30 years of research on cold-water vibriosis (CWV). The diseased caused by Aliivibrio salmonicida (earlier known as Vibrio salmonicida) was for the first time described in 1986 and became one of the most important bacterial diseases in salmon aquaculture. The lack of appropriate vaccine hampered development of Atlantic salmon aquaculture until the late 1980s when a novel vaccine allowed dramatic increase in the Atlantic salmon farming. In December 2007, the genus Vibrio was split into two genera and several bacterial species including V. salmonicida were transferred to genus Aliivibrio. The change of the names create significant difficulties with the designation of the CWV disease agent since its abbreviation A. salmonicida became similar to another well-known salmon pathogen Aeromonas salmonicida (A. salmonicida). The disease was considered as controlled by vaccination, but reappeared at Atlantic salmon farms in 2011, this time affecting vaccinated Atlantic salmon. The current review summarizes the knowledge on pathogenesis, vaccination and treatment of CWV and proposes further directions for studying the disease.
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Affiliation(s)
- A Kashulin
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
| | - N Seredkina
- Department of Medical Biology, Arctic University of Norway, Tromsø, Norway
| | - H Sørum
- Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, Oslo, Norway
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20
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Guijarro JA, Cascales D, García-Torrico AI, García-Domínguez M, Méndez J. Temperature-dependent expression of virulence genes in fish-pathogenic bacteria. Front Microbiol 2015. [PMID: 26217329 PMCID: PMC4496569 DOI: 10.3389/fmicb.2015.00700] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Virulence gene expression in pathogenic bacteria is modulated by environmental parameters. A key factor in this expression is temperature. Its effect on virulence gene expression in bacteria infecting warm-blooded hosts is well documented. Transcription of virulence genes in these bacteria is induced upon a shift from low environmental to a higher host temperature (37°C). Interestingly, host temperatures usually correspond to the optimum for growth of these pathogenic bacteria. On the contrary, in ectothermic hosts such as fish, molluscs, and amphibians, infection processes generally occur at a temperature lower than that for the optimal growth of the bacteria. Therefore, regulation of virulence gene expression in response to temperature shift has to be modulated in a different way to that which is found in bacteria infecting warm-blooded hosts. The current understanding of virulence gene expression and its regulation in response to temperature in fish-pathogenic bacteria is limited, but constant extension of our knowledge base is essential to enable a rational approach to the problem of the bacterial fish diseases affecting the aquaculture industry. This is an interesting issue and progress needs to be made in order to diminish the economic losses caused by these diseases. The intention of this review is, for the first time, to compile the scattered results existing in the field in order to lay the groundwork for future research. This article is an overview of those relevant virulence genes that are expressed at temperatures lower than that for optimal bacterial growth in different fish-pathogenic bacteria as well as the principal mechanisms that could be involved in their regulation.
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Affiliation(s)
- José A. Guijarro
- *Correspondence: José A. Guijarro, Área de Microbiología, Departamento de Biología Funcional, Facultad de Medicina, Instituto de Biotecnología de Asturias, Universidad de Oviedo, C/Julían Clavería 6, 33006 Oviedo, Spain,
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21
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Hansen H, Purohit AA, Leiros HKS, Johansen JA, Kellermann SJ, Bjelland AM, Willassen NP. The autoinducer synthases LuxI and AinS are responsible for temperature-dependent AHL production in the fish pathogen Aliivibrio salmonicida. BMC Microbiol 2015; 15:69. [PMID: 25886758 PMCID: PMC4377199 DOI: 10.1186/s12866-015-0402-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 03/11/2015] [Indexed: 11/25/2022] Open
Abstract
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 when the seawater is below 12°C. In this work we have constructed several mutants of A. salmonicida LFI1238 in order to study the LuxI/LuxR and AinS/AinR QS systems with respect to AHL production and biofilm formation. Results Using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) we found that LuxI in A. salmonicida LFI1238 is responsible for producing seven of the different AHLs, whereas AinS is responsible for producing only one. The production of these various AHLs is dependent on both cell density and growth temperature. The AHLs were efficiently produced when wild type LFI1238 was grown at 6 or 12°C, however at 16°C AHL production decreased dramatically, and LFI1238 produced less than 5% of the maximum concentrations observed at 6°C. LitR, the master regulator of QS, was found to be a positive regulator of AinS-dependent AHL production, and to a lesser extent LuxI-dependent AHL production. This implies a connection between the two systems, and both systems were found to be involved in regulation of biofilm formation. Finally, inactivation of either luxR1 or luxR2 in the lux operon significantly reduced production of LuxI-produced AHLs. Conclusion LuxI and AinS are the autoinducer synthases responsible for the eight AHLs in A. salmonicida. AHL production is highly dependent on growth temperature, and a significant decrease was observed when the bacterium was grown at a temperature above its limit for disease outbreak. Numerous AHLs could offer the opportunity for fine-tuning responses to changes in the environment. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0402-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hilde Hansen
- Norwegian Structural Biology Centre and the Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, N-9037, Tromsø, Norway.
| | - Amit Anand Purohit
- Norwegian Structural Biology Centre and the Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, N-9037, Tromsø, Norway.
| | - Hanna-Kirsti S Leiros
- Norwegian Structural Biology Centre and the Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, N-9037, Tromsø, Norway.
| | - Jostein A Johansen
- Norwegian Structural Biology Centre and the Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, N-9037, Tromsø, Norway.
| | - Stefanie J Kellermann
- Norwegian Structural Biology Centre and the Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, N-9037, Tromsø, Norway. .,Current address: Department of Chemistry and Pharmacy, Institute of Biochemistry, University of Münster, Wilhelm-Klemm-Straße 2, 48149, Münster, Germany.
| | - Ane Mohn Bjelland
- Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Akershus, Norway.
| | - Nils Peder Willassen
- Norwegian Structural Biology Centre and the Department of Chemistry, Faculty of Science and Technology, UiT The Arctic University of Norway, N-9037, Tromsø, Norway.
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22
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LitR is a repressor of syp genes and has a temperature-sensitive regulatory effect on biofilm formation and colony morphology in Vibrio (Aliivibrio) salmonicida. Appl Environ Microbiol 2014; 80:5530-41. [PMID: 24973072 DOI: 10.1128/aem.01239-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vibrio (Aliivibrio) salmonicida is the etiological agent of cold water vibriosis, a disease in farmed Atlantic salmon (Salmo salar) that is kept under control due to an effective vaccine. A seawater temperature below 12°C is normally required for disease development. Quorum sensing (QS) is a cell density-regulated communication system that bacteria use to coordinate activities involved in colonization and pathogenesis, and we have previously shown that inactivation of the QS master regulator LitR attenuates the V. salmonicida strain LFI1238 in a fish model. We show here that strain LFI1238 and a panel of naturally occurring V. salmonicida strains are poor biofilm producers. Inactivation of litR in the LFI1238 strain enhances medium- and temperature-dependent adhesion, rugose colony morphology, and biofilm formation. Chemical treatment and electron microscopy of the biofilm identified an extracellular matrix consisting mainly of a fibrous network, proteins, and polysaccharides. Further, by microarray analysis of planktonic and biofilm cells, we identified a number of genes regulated by LitR and, among these, were homologues of the Vibrio fischeri symbiosis polysaccharide (syp) genes. The syp genes were regulated by LitR in both planktonic and biofilm lifestyle analyses. Disruption of syp genes in the V. salmonicida ΔlitR mutant alleviated adhesion, rugose colony morphology, and biofilm formation. Hence, LitR is a repressor of syp transcription that is necessary for expression of the phenotypes examined. The regulatory effect of LitR on colony morphology and biofilm formation is temperature sensitive and weak or absent at temperatures above the bacterium's upper threshold for pathogenicity.
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Poćwierz-Kotus A, Kijewska A, Petereit C, Bernaś R, Więcaszek B, Arnyasi M, Lien S, Kent MP, Wenne R. Genetic differentiation of brackish water populations of cod Gadus morhua in the southern Baltic, inferred from genotyping using SNP-arrays. Mar Genomics 2014; 19:17-22. [PMID: 24910372 DOI: 10.1016/j.margen.2014.05.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 05/23/2014] [Accepted: 05/26/2014] [Indexed: 11/27/2022]
Abstract
The Baltic is a semi-enclosed sea characterised by decreasing salinity in the eastern and northern direction with only the deeper parts of the southern Baltic suitable as spawning grounds for marine species like cod. Baltic cod exhibits various adaptations to brackish water conditions, yet the inflow of salty North Sea water near the bottom remains an influence on the spawning success of the Baltic cod. The eastern Baltic population has been very weakly studied in comparison with the western population. The aim of this study is to demonstrate for the first time genetic differentiation by the use of a large number of SNPs between eastern and western Baltic populations existing in differentiated salinity conditions. Two cod samples were collected from the Bay of Gdańsk, Poland and one from the Kiel Bight, Germany. Samples were genotyped using a cod derived SNP-array (Illumina) with 10 913 SNPs. A selection of diagnostic SNPs was performed. A set of 7944 validated SNPs were analysed to assess the differentiation of three samples of cod. Results indicated a clear distinctness of the Kiel Bight from the populations of the eastern Baltic. FST comparison between both eastern samples was non-significant. Clustering analysis, principal coordinates analysis and assignment test clearly indicated that the eastern samples should be considered as one subpopulation, well differentiated from the western subpopulation. With the SNP approach, no differentiation between groups containing 'healthy' and 'non-healthy' cod individuals was observed.
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Affiliation(s)
- A Poćwierz-Kotus
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
| | - A Kijewska
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
| | - C Petereit
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Research Unit: Evolutionary Ecology of Marine Fish, 24105 Kiel, Germany
| | - R Bernaś
- Department of Migratory Fishes in Gdansk, Inland Fisheries Institute, Olsztyn, Poland
| | - B Więcaszek
- Department of Fish Systematics, Faculty of Food Sciences and Fisheries, West Pomeranian University of Technology, K. Krolewicza 4, 71-550 Szczecin, Poland
| | - M Arnyasi
- Centre for Integrative Genetics (CIGENE), Norwegian University of Life Sciences, Ås, Norway
| | - S Lien
- Centre for Integrative Genetics (CIGENE), Norwegian University of Life Sciences, Ås, Norway
| | - M P Kent
- Centre for Integrative Genetics (CIGENE), Norwegian University of Life Sciences, Ås, Norway
| | - R Wenne
- Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
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24
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Bjelland AM, Fauske AK, Nguyen A, Orlien IE, Ostgaard IM, Sørum H. Expression of Vibrio salmonicida virulence genes and immune response parameters in experimentally challenged Atlantic salmon (Salmo salar L.). Front Microbiol 2013; 4:401. [PMID: 24391635 PMCID: PMC3868895 DOI: 10.3389/fmicb.2013.00401] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 12/05/2013] [Indexed: 11/13/2022] Open
Abstract
The Gram-negative bacterium Vibrio salmonicida is the causative agent of cold-water vibriosis (CV), a hemorrhagic septicemia that primarily affects farmed Atlantic salmon (Salmo salar L.). The mechanisms of disease development, host specificity and adaptation, as well as the immunogenic properties of V. salmonicida are largely unknown. Therefore, to gain more knowledge on the pathogenesis of CV, 90 Atlantic salmon parr were injected intraperitoneally with 6 × 10(6) CFU of V. salmonicida LFI1238. Samples from blood and spleen tissue were taken at different time points throughout the challenge for gene expression analysis by two-step reverse transcription (RT) quantitative real-time polymerase chain reaction. Out of a panel of six housekeeping genes, accD, gapA, and 16S rDNA were found to be the most suitable references for expression analysis in Vibrio salmonicida. The bacterial proliferation during challenge was monitored based on the expression of the 16S rRNA encoding gene. Before day 4, the concentrations of V. salmonicida in blood and spleen tissue demonstrated a lag phase. From day 4, the bacterial proliferation was exponential. The expression profiles of eight genes encoding potential virulence factors of V. salmonicida were studied. Surprisingly, all tested virulence genes were generally highest expressed in broth cultures compared to the in vivo samples. We hypothesize that this general muting of gene expression in vivo may be a strategy for V. salmonicida to hide from the host immune system. To further investigate this hypothesis, the expression profiles of eight genes encoding innate immune factors were analyzed. The results demonstrated a strong and rapid, but short-lasting innate immune response against V. salmonicida. These results suggest that the bacterium possesses mechanisms that inhibit and/or resist the salmon innate immune system until the host becomes exhausted of fighting the on-going and eventually overwhelming infection.
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Affiliation(s)
- Ane M Bjelland
- Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science Oslo, Norway
| | - Aud K Fauske
- Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science Oslo, Norway
| | - Anh Nguyen
- Department of Pharmacy and Biomedical Laboratory Sciences, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences Oslo, Norway
| | - Ingvild E Orlien
- Department of Pharmacy and Biomedical Laboratory Sciences, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences Oslo, Norway
| | - Ingrid M Ostgaard
- Department of Pharmacy and Biomedical Laboratory Sciences, Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences Oslo, Norway
| | - Henning Sørum
- Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science Oslo, Norway
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25
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Defoirdt T. Antivirulence therapy for animal production: filling an arsenal with novel weapons for sustainable disease control. PLoS Pathog 2013; 9:e1003603. [PMID: 24130477 PMCID: PMC3795005 DOI: 10.1371/journal.ppat.1003603] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Affiliation(s)
- Tom Defoirdt
- Laboratory of Aquaculture and Artemia Reference Center, Ghent University, Ghent, Belgium
- Laboratory of Microbial Ecology and Technology, Ghent University, Ghent, Belgium
- * E-mail:
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26
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Johnson CN. Fitness factors in vibrios: a mini-review. MICROBIAL ECOLOGY 2013; 65:826-851. [PMID: 23306394 DOI: 10.1007/s00248-012-0168-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
Vibrios are Gram-negative curved bacilli that occur naturally in marine, estuarine, and freshwater systems. Some species include human and animal pathogens, and some vibrios are necessary for natural systems, including the carbon cycle and osmoregulation. Countless in vivo and in vitro studies have examined the interactions between vibrios and their environment, including molecules, cells, whole animals, and abiotic substrates. Many studies have characterized virulence factors, attachment factors, regulatory factors, and antimicrobial resistance factors, and most of these factors impact the organism's fitness regardless of its external environment. This review aims to identify common attributes among factors that increase fitness in various environments, regardless of whether the environment is an oyster, a rabbit, a flask of immortalized mammalian cells, or a planktonic chitin particle. This review aims to summarize findings published thus far to encapsulate some of the basic similarities among the many vibrio fitness factors and how they frame our understanding of vibrio ecology. Factors representing these similarities include hemolysins, capsular polysaccharides, flagella, proteases, attachment factors, type III secretion systems, chitin binding proteins, iron acquisition systems, and colonization factors.
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Affiliation(s)
- Crystal N Johnson
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA, USA.
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27
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Ahmad R, Hansen GÅ, Hansen H, Hjerde E, Pedersen HL, Paulsen SM, Nyrud MLJ, Strauss A, Willassen NP, Haugen P. Prediction, Microarray and Northern Blot Analyses Identify New Intergenic Small RNAs in Aliivibrio salmonicida. J Mol Microbiol Biotechnol 2012; 22:352-60. [DOI: 10.1159/000345769] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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28
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Efficient surface modification of biomaterial to prevent biofilm formation and the attachment of microorganisms. Appl Microbiol Biotechnol 2012; 95:299-311. [DOI: 10.1007/s00253-012-4144-7] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 04/27/2012] [Accepted: 04/28/2012] [Indexed: 02/07/2023]
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