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Wang Q, Ji F, Guo J, Wang Y, Li Y, Wang J, An L, Bao Y. LotS/LotR/Clp, a novel signal pathway responding to temperature, modulating protease expression via c-di-GMP mediated manner in Stenotrophomonas maltophilia FF11. Microbiol Res 2018; 214:60-73. [PMID: 30031482 DOI: 10.1016/j.micres.2018.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 04/30/2018] [Accepted: 05/17/2018] [Indexed: 11/25/2022]
Abstract
Stenotrophomonas maltophilia as one of increasing food spoilage bacteria and fish pathogens has become a threat to aquiculture industry. A major factor contributing to the success of bacterium is its outstanding ability to secrete protease at low temperatures. Here, a cAMP receptor like protein (Clp) shows a positive regulation on this protease, named S. maltophilia temperature-response protease (SmtP). Interestingly, a two-component system, comprising of LotS sensor and LotR regulator, for low-temperature response is also confirmed to modulate SmtP expression with similar effect to Clp. Evidence is presented that LotS/LotR modulates smtP (coding SmtP) expression via Clp: clp promoter activity was reduced significantly at low temperatures and protease activity was partially restored by Clp overexpressed in lotS or lotR deletion strain. Furthermore, as a Clp negative effector, the binding ability of c-di-GMP with Clp is not impacted by temperature. c-di-GMP level was increased in S. maltophilia growing at high temperature, but not exhibited significantly in lotR deleted strain, these indicate that LotR is required for temperature modulating c-di-GMP level, although the synthesis or degradation activity of c-di-GMP by LotR was not detected. These findings suggest that LotS/LotR/Clp play an important role in responding to temperature stimuli via c-di-GMP mediated manner.
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Affiliation(s)
- Qingling Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Fangling Ji
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Jianli Guo
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yuepeng Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yanyan Li
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Jingyun Wang
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Lijia An
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China
| | - Yongming Bao
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China; School of Food and Environment Science and Technology, Dalian University of Technology, Panjin, 124221, China.
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Abram QH, Dixon B, Katzenback BA. Impacts of Low Temperature on the Teleost Immune System. BIOLOGY 2017; 6:E39. [PMID: 29165340 PMCID: PMC5745444 DOI: 10.3390/biology6040039] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 11/14/2017] [Accepted: 11/14/2017] [Indexed: 12/17/2022]
Abstract
As poikilothermic vertebrates, fish can experience changes in water temperature, and hence body temperature, as a result of seasonal changes, migration, or efflux of large quantities of effluent into a body of water. Temperature shifts outside of the optimal temperature range for an individual fish species can have negative impacts on the physiology of the animal, including the immune system. As a result, acute or chronic exposure to suboptimal temperatures can impair an organisms' ability to defend against pathogens and thus compromise the overall health of the animal. This review focuses on the advances made towards understanding the impacts of suboptimal temperature on the soluble and cellular mediators of the innate and adaptive immune systems of fishes. Although cold stress can result in varying effects in different fish species, acute and chronic suboptimal temperature exposure generally yield suppressive effects, particularly on adaptive immunity. Knowledge of the effects of environmental temperature on fish species is critical for both the optimal management of wild species and the best management practices for aquaculture species.
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Affiliation(s)
- Quinn H Abram
- Department of Biology, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1, Canada.
| | - Brian Dixon
- Department of Biology, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1, Canada.
| | - Barbara A Katzenback
- Department of Biology, University of Waterloo, 200 University Ave West, Waterloo, ON N2L 3G1, Canada.
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Santander RD, Biosca EG. Erwinia amylovora psychrotrophic adaptations: evidence of pathogenic potential and survival at temperate and low environmental temperatures. PeerJ 2017; 5:e3931. [PMID: 29085749 PMCID: PMC5660878 DOI: 10.7717/peerj.3931] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 09/26/2017] [Indexed: 12/12/2022] Open
Abstract
The fire blight pathogen Erwinia amylovora can be considered a psychrotrophic bacterial species since it can grow at temperatures ranging from 4 °C to 37 °C, with an optimum of 28 °C. In many plant pathogens the expression of virulence determinants is restricted to a certain range of temperatures. In the case of E. amylovora, temperatures above 18 °C are required for blossom blight epidemics under field conditions. Moreover, this bacterium is able to infect a variety of host tissues/organs apart from flowers, but it is still unknown how environmental temperatures, especially those below 18 °C, affect the pathogen ability to cause fire blight disease symptoms in such tissues/organs. There is also scarce information on how temperatures below 18 °C affect the E. amylovora starvation-survival responses, which might determine its persistence in the environment and probably contribute to the seasonal development of fire blight disease, as occurs in other pathogens. To characterize the virulence and survival of E. amylovora at temperate and low temperatures, we evaluated the effect of three temperatures (4 °C, 14 °C, 28 °C) on symptom development, and on different parameters linked to starvation and virulence. E. amylovora was pathogenic at the three assayed temperatures, with a slow-down of symptom development correlating with colder temperatures and slower growth rates. Siderophore secretion and motility also decreased in parallel to incubation temperatures. However, production of the exopolysaccharides amylovoran and levan was enhanced at 4 °C and 14 °C, respectively. Similarly, biofilm formation, and oxidative stress resistance were improved at 14 °C, with this temperature also favoring the maintenance of culturability, together with a reduction in cell size and the acquisition of rounded shapes in E. amylovora cells subjected to long-term starvation. However, starvation at 28 °C and 4 °C induced an enhanced viable but nonculturable (VBNC) response (to a lesser extent at 4 °C). This work reveals E. amylovora as a highly adaptable pathogen that retains its pathogenic potential even at the minimal growth temperatures, with an improved exopolysaccharide synthesis, biofilm formation or oxidative stress resistance at 14 °C, with respect to the optimal growth temperature (28 °C). Finally, our results also demonstrate the thermal modulation of starvation responses in E. amylovora, suggesting that the starvation-survival and the VBNC states are part of its life cycle. These results confirm the particular psychrotrophic adaptations of E. amylovora, revealing its pathogenic potential and survival at temperate and low environmental temperatures, which have probably contributed to its successful spread to countries with different climates. This knowledge might improve integrated control measures against fire blight.
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Affiliation(s)
- Ricardo D. Santander
- Department of Microbiology and Ecology, Universitat de València, Burjassot, Spain
| | - Elena G. Biosca
- Department of Microbiology and Ecology, Universitat de València, Burjassot, Spain
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Castro R, Reguera-Brito M, López-Campos GH, Blanco MM, Aguado-Urda M, Fernández-Garayzábal JF, Gibello A. How does temperature influences the development of lactococcosis? Transcriptomic and immunoproteomic in vitro approaches. JOURNAL OF FISH DISEASES 2017; 40:1285-1297. [PMID: 28093775 DOI: 10.1111/jfd.12601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/21/2016] [Accepted: 11/22/2016] [Indexed: 06/06/2023]
Abstract
Lactococcus garvieae is the aetiological agent of lactococcosis, a haemorrhagic septicaemia that affects marine and freshwater fish, with special incidence and economic relevance in farmed rainbow trout. Water temperature is one of the most important predisposing factors in the development of lactococcosis outbreaks. Lactococcosis in trout usually occur when water temperatures rise to about 18 °C, while fish carriers remain asymptomatic at temperatures below 13 °C. The aim of this work was to analyse the differences in the complete transcriptome response of L. garvieae grown at 18 °C and at 13 °C and to identify the immunogenic proteins expressed by this bacterium at 18 °C. Our results show that water temperature influences the expression of L. garvieae genes involved in the lysis of part of the bacterial cell population and in the cold response bacterial adaptation. Moreover, the surface immunogenic protein profile at 18 °C suggests an important role of the lysozyme-like enzyme, WxL surface proteins and some putative moonlighting proteins (proteins with more than one function, usually associated with different cellular locations) as virulence factors in L. garvieae. The results of this study could provide insights into the understanding of the virulence mechanisms of L. garvieae in fish.
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Affiliation(s)
- R Castro
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - M Reguera-Brito
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - G H López-Campos
- Health and Biomedical Informatics Research Unit, Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - M M Blanco
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - M Aguado-Urda
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
| | - J F Fernández-Garayzábal
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
- Animal Health Surveillance Center (VISAVET), Complutense University, Madrid, Spain
| | - A Gibello
- Department of Animal Health, Faculty of Veterinary Sciences, Complutense University, Madrid, Spain
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Abdallah RA, Beye M, Diop A, Bakour S, Raoult D, Fournier PE. The impact of culturomics on taxonomy in clinical microbiology. Antonie van Leeuwenhoek 2017; 110:1327-1337. [PMID: 28389704 DOI: 10.1007/s10482-017-0871-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 04/04/2017] [Indexed: 02/06/2023]
Abstract
Over the past decade, new culture methods coupled to genome and metagenome sequencing have enabled the number of isolated bacterial species with standing in nomenclature to rise to more than 15,000 whereas it was only 1791 in 1980. 'Culturomics', a new approach based on the diversification of culture conditions, has enabled the isolation of more than 1000 distinct human-associated bacterial species since 2012, including 247 new species. This strategy was demonstrated to be complementary to metagenome sequencing for the exhaustive study of the human microbiota and its roles in health and diseases. However, by identifying a large number of new bacterial species in a short time, culturomics has highlighted a need for taxonomic approaches adapted to clinical microbiology that would include the use of modern and reproducible tools, including high throughput genomic and proteomic analyses. Herein, we review the development of culturomics and genomics in the clinical microbiology field and their impact on bacterial taxonomy.
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Affiliation(s)
- Rita Abou Abdallah
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63CNRS 7278IRD 198Inserm 1095IHU Méditerranée Infection, Faculté de Médecine, Aix-Marseille Université, 27 Bd Jean Moulin, 13385, Marseille Cedex5, France
| | - Mamadou Beye
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63CNRS 7278IRD 198Inserm 1095IHU Méditerranée Infection, Faculté de Médecine, Aix-Marseille Université, 27 Bd Jean Moulin, 13385, Marseille Cedex5, France
| | - Awa Diop
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63CNRS 7278IRD 198Inserm 1095IHU Méditerranée Infection, Faculté de Médecine, Aix-Marseille Université, 27 Bd Jean Moulin, 13385, Marseille Cedex5, France
| | - Sofiane Bakour
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63CNRS 7278IRD 198Inserm 1095IHU Méditerranée Infection, Faculté de Médecine, Aix-Marseille Université, 27 Bd Jean Moulin, 13385, Marseille Cedex5, France
| | - Didier Raoult
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63CNRS 7278IRD 198Inserm 1095IHU Méditerranée Infection, Faculté de Médecine, Aix-Marseille Université, 27 Bd Jean Moulin, 13385, Marseille Cedex5, France
| | - Pierre-Edouard Fournier
- Unité de recherche sur les maladies infectieuses et tropicales émergentes (URMITE), UM 63CNRS 7278IRD 198Inserm 1095IHU Méditerranée Infection, Faculté de Médecine, Aix-Marseille Université, 27 Bd Jean Moulin, 13385, Marseille Cedex5, France.
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Levipan HA, Avendaño-Herrera R. Different Phenotypes of Mature Biofilm in Flavobacterium psychrophilum Share a Potential for Virulence That Differs from Planktonic State. Front Cell Infect Microbiol 2017; 7:76. [PMID: 28361040 PMCID: PMC5350093 DOI: 10.3389/fcimb.2017.00076] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 02/27/2017] [Indexed: 12/31/2022] Open
Abstract
Flavobacterium psychrophilum is the etiological agent of bacterial coldwater disease and the rainbow trout fry syndrome in salmonid aquaculture worldwide. However, there have been few studies into the capacity of F. psychrophilum to form biofilms and how these cellular accretions differ from planktonic cells or how they affect potential virulence. We evaluated the biofilm formation by three Chilean isolates of F. psychrophilum (LM-02-Fp, LM-06-Fp, and LM-13-Fp) and two non-Chilean strains (JIP02/86 and NCMB1947T), and compared biofilm and planktonic states to obtain insights into expression differences of virulence- and biofilm-related genes (VBRGs). Our findings are based on scanning confocal laser microscopy (SCLM) and LIVE/DEAD staining, enzymatic reactions, reverse transcription-quantitative PCR (RT-qPCR) of genes encoding putative virulence factors, and transcriptomes (RNA-Seq). The LM-02-Fp and NCMB1947T strains were the strongest and weakest biofilm producers, respectively. The strong-biofilm producer showed different physiological cell states distributed in different layers of mature biofilms, whereas the NCMB1947T biofilms consisted of cells arranged in a monolayer. WGA-binding exopolysaccharides would be the main components of their corresponding extracellular matrices. Transcriptomes of F. psychrophilum NCMB1947T and LM-02-Fp were clustered by state (biofilm vs. planktonic) rather than by strain, indicating important state-dependent differences in gene expression. Analysis of differentially expressed genes between states identified putative VBRGs involved in polysaccharide biosynthesis, lateral gene transfer, membrane transport (e.g., for drugs and Fe3+), sensory mechanisms, and adhesion, and indicated that about 60-100% of VBRGs involved in these processes was significantly upregulated in the biofilm state. Conversely, upregulated motility-related genes in the biofilm state were not identified, whereas a lower fraction of proteolysis-related genes (33%) was upregulated in biofilms. In summary, F. psychrophilum strains that produce different biofilm phenotypes show global transcriptional activity in the mature biofilm state that differs significantly from their planktonic counterparts. Also, different biofilm phenotypes share a genetic potential for virulence that is transcriptionally enhanced with respect to free-living cells. Our results suggest that the F. psychrophilum biofilm lifestyle acts as a reservoir for a given set of putative virulence factors, and recommend a deeper understanding of which could help prevent recurring infections in salmonid farms.
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Affiliation(s)
- Héctor A Levipan
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andres BelloViña del Mar, Chile; Interdisciplinary Center for Aquaculture ResearchConcepción, Chile
| | - Ruben Avendaño-Herrera
- Laboratorio de Patología de Organismos Acuáticos y Biotecnología Acuícola, Facultad de Ciencias Biológicas, Universidad Andres BelloViña del Mar, Chile; Interdisciplinary Center for Aquaculture ResearchConcepción, Chile; Centro de Investigación Marina QuintayValparaíso, Chile
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Rey S, Moiche V, Boltaña S, Teles M, MacKenzie S. Behavioural fever in zebrafish larvae. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 67:287-292. [PMID: 27670815 DOI: 10.1016/j.dci.2016.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 09/15/2016] [Accepted: 09/15/2016] [Indexed: 06/06/2023]
Abstract
Behavioural fever has been reported in different species of mobile ectotherms including the zebrafish, Danio rerio, in response to exogenous pyrogens. In this study we report, to our knowledge for the first time, upon the ontogenic onset of behavioural fever in zebrafish (Danio rerio) larvae. For this, zebrafish larvae (from first feeding to juveniles) were placed in a continuous thermal gradient providing the opportunity to select their preferred temperature. The novel thermal preference aquarium was based upon a continuous vertical column system and allows for non-invasive observation of larvae vertical distribution under isothermal (TR at 28 °C) and thermal gradient conditions (TCH: 28-32 °C). Larval thermal preference was assessed under both conditions with or without an immersion challenge, in order to detect the onset of the behavioural fever response. Our results defined the onset of the dsRNA induced behavioural fever at 18-20 days post fertilization (dpf). Significant differences were observed in dsRNA challenged larvae, which prefer higher temperatures (1-4 °C increase) throughout the experimental period as compared to non-challenged larvae. In parallel we measured the abundance of antiviral transcripts; viperin, gig2, irf7, trim25 and Mxb mRNAs in dsRNA challenged larvae under both thermal regimes: TR and TCh. Significant increases in the abundance of all measured transcripts were recorded under thermal choice conditions signifying that thermo-coupling and the resultant enhancement of the immune response to dsRNA challenge occurs from 18 dpf onwards in the zebrafish. The results are of importance as they identify a key developmental stage where the neuro-immune interface matures in the zebrafish likely providing increased resistance to viral infection.
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Affiliation(s)
- Sonia Rey
- Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, 08193 Bellaterra, Spain
| | - Visila Moiche
- Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, 08193 Bellaterra, Spain
| | - Sebastian Boltaña
- Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, 08193 Bellaterra, Spain
| | - Mariana Teles
- Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, 08193 Bellaterra, Spain
| | - Simon MacKenzie
- Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Barcelona, 08193 Bellaterra, Spain.
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Transcriptomic Analysis of Laribacter hongkongensis Reveals Adaptive Response Coupled with Temperature. PLoS One 2017; 12:e0169998. [PMID: 28085929 PMCID: PMC5234827 DOI: 10.1371/journal.pone.0169998] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 12/27/2016] [Indexed: 12/17/2022] Open
Abstract
Bacterial adaptation to different hosts requires transcriptomic alteration in response to the environmental conditions. Laribacter hongkongensis is a gram-negative, facultative anaerobic, urease-positive bacillus caused infections in liver cirrhosis patients and community-acquired gastroenteritis. It was also found in intestine from commonly consumed freshwater fishes and drinking water reservoirs. Since L. hongkongensis could survive as either fish or human pathogens, their survival mechanisms in two different habitats should be temperature-regulated and highly complex. Therefore, we performed transcriptomic analysis of L. hongkongensis at body temperatures of fish and human in order to elucidate the versatile adaptation mechanisms coupled with the temperatures. We identified numerous novel temperature-induced pathways involved in host pathogenesis, in addition to the shift of metabolic equilibriums and overexpression of stress-related proteins. Moreover, these pathways form a network that can be activated at a particular temperature, and change the physiology of the bacteria to adapt to the environments. In summary, the dynamic of transcriptomes in L. hongkongensis provides versatile strategies for the bacterial survival at different habitats and this alteration prepares the bacterium for the challenge of host immunity.
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Penttinen R, Kinnula H, Lipponen A, Bamford JKH, Sundberg LR. High Nutrient Concentration Can Induce Virulence Factor Expression and Cause Higher Virulence in an Environmentally Transmitted Pathogen. MICROBIAL ECOLOGY 2016; 72:955-964. [PMID: 27193154 DOI: 10.1007/s00248-016-0781-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/04/2016] [Indexed: 05/13/2023]
Abstract
Environmentally transmitted opportunistic pathogens shuttle between two substantially different environments: outside-host and within-host habitats. These environments differ from each other especially with respect to nutrient availability. Consequently, the pathogens are required to regulate their behavior in response to environmental cues in order to survive, but how nutrients control the virulence in opportunistic pathogens is still poorly understood. In this study, we examined how nutrient level in the outside-host environment affects the gene expression of putative virulence factors of the opportunistic fish pathogen Flavobacterium columnare. The impact of environmental nutrient concentration on bacterial virulence was explored by cultivating the bacteria in various nutrient conditions, measuring the gene expression of putative virulence factors with RT-qPCR and, finally, experimentally challenging rainbow trout (Oncorhynchus mykiss) fry with these bacteria. Our results show that increased environmental nutrient concentration can increase the expression of putative virulence genes, chondroitinase (cslA) and collagenase, in the outside-host environment and may lead to more rapid fish mortality. These findings address that the environmental nutrients may act as significant triggers of virulence gene expression and therefore contribute to the interaction between an environmentally transmitted opportunistic pathogen and its host.
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Affiliation(s)
- Reetta Penttinen
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Center of Excellence in Biological Interactions, P.O. Box 35, FI-40014, University of Jyvaskyla, Jyvaskyla, Finland.
| | - Hanna Kinnula
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Center of Excellence in Biological Interactions, P.O. Box 35, FI-40014, University of Jyvaskyla, Jyvaskyla, Finland
| | - Anssi Lipponen
- University of Eastern Finland, A.I. Virtanen Institute for Molecular Sciences, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Jaana K H Bamford
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Center of Excellence in Biological Interactions, P.O. Box 35, FI-40014, University of Jyvaskyla, Jyvaskyla, Finland
| | - Lotta-Riina Sundberg
- Department of Biological and Environmental Science and Nanoscience Center, University of Jyvaskyla, Center of Excellence in Biological Interactions, P.O. Box 35, FI-40014, University of Jyvaskyla, Jyvaskyla, Finland
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Hapeshi A, Waterfield NR. Photorhabdus asymbiotica as an Insect and Human Pathogen. Curr Top Microbiol Immunol 2016; 402:159-177. [PMID: 27726002 DOI: 10.1007/82_2016_29] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Photorhabdus asymbiotica is a species of bacterium that is pathogenic to humans whilst retaining the ability to infect insect hosts. Currently, there are two recognised subspecies, P. asymbiotica subsp. asymbiotica and P. asymbiotica subsp. australis with strains isolated from various locations in the USA, Australia, Thailand, Nepal and Europe. Like other species of Photorhabdus, P. asymbiotica subsp. australis was shown to form a symbiotic relationship with a Heterorhabditis nematode. In contrast to most strains of Photorhabdus luminescens, P. asymbiotica can grow at 37 °C and this is a defining factor in its ability to cause human disease. Insights into other adaptations it has undergone that have enabled host switching to occur have come from whole genome sequencing and transcriptomic studies. P. asymbiotica has a smaller genome compared to P. luminenscens with a lower diversity of insecticidal toxins. However, it has acquired plasmids and several pathogenicity islands in its genome. These encode genes with similarity to effectors or systems found in other known human pathogens such as Salmonella and Yersinia and are therefore likely to contribute to human pathogenicity. Of crucial importance to virulence is the fact that P. asymbiotica undergoes a large metabolic shift at the human host temperature.
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Affiliation(s)
- Alexia Hapeshi
- Warwick Medical School, University of Warwick, Coventry, UK
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