uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Melanization and Pathogenicity in the Insect, Tenebrio molitor, and the Crustacean, Pacifastacus leniusculus, by Aeromonas hydrophila AH-3
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Comparative Physiology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Comparative Physiology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Comparative Physiology.
Show others and affiliations
2010 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 5, no 12, e15728- p.Article in journal (Refereed) Published
Abstract [en]

Aeromonas hydrophila is the most common Aeromonas species causing infections in human and other animals such as amphibians, reptiles, fish and crustaceans. Pathogenesis of Aeromonas species have been reported to be associated with virulence factors such as lipopolysaccharides (LPS), bacterial toxins, bacterial secretion systems, flagella, and other surface molecules. Several mutant strains of A. hydrophila AH-3 were initially used to study their virulence in two animal species, Pacifastacus leniusculus (crayfish) and Tenebrio molitor larvae (mealworm). The AH-3 strains used in this study have mutations in genes involving the synthesis of flagella, LPS structures, secretion systems, and some other factors, which have been reported to be involved in A. hydrophila pathogenicity. Our study shows that the LPS (O-antigen and external core) is the most determinant A. hydrophila AH-3 virulence factor in both animals. Furthermore, we studied the immune responses of these hosts to infection of virulent or non-virulent strains of A. hydrophila AH-3. The AH-3 wild type (WT) containing the complete LPS core is highly virulent and this bacterium strongly stimulated the prophenoloxidase activating system resulting in melanization in both crayfish and mealworm. In contrast, the ΔwaaE mutant which has LPS without O-antigen and external core was non-virulent and lost ability to stimulate this system and melanization in these two animals. The high phenoloxidase activity found in WT infected crayfish appears to result from a low expression of pacifastin, a prophenoloxidase activating enzyme inhibitor, and this gene expression was not changed in the ΔwaaE mutant infected animal and consequently phenoloxidase activity was not altered as compared to non-infected animals. Therefore we show that the virulence factors of A. hydrophila are the same regardless whether an insect or a crustacean is infected and the O-antigen and external core is essential for activation of the proPO system and as virulence factors for this bacterium.

Place, publisher, year, edition, pages
2010. Vol. 5, no 12, e15728- p.
National Category
Biological Sciences
Identifiers
URN: urn:nbn:se:uu:diva-141552DOI: 10.1371/journal.pone.0015728ISI: 000285793200045PubMedID: 21206752OAI: oai:DiVA.org:uu-141552DiVA: diva2:385777
Available from: 2011-01-12 Created: 2011-01-12 Last updated: 2017-12-11
In thesis
1. Hemocyte Homeostasis and Infection in the Freshwater Crayfish, Pacifastacus leniusculus
Open this publication in new window or tab >>Hemocyte Homeostasis and Infection in the Freshwater Crayfish, Pacifastacus leniusculus
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Uppsala: Department of Comparative Physiology, Uppsala University, 2012. 26 p.
National Category
Immunology
Research subject
Biology with specialization in Comparative Physiology
Identifiers
urn:nbn:se:uu:diva-173690 (URN)
Presentation
2012-03-23, Lagerträdet 05:01021, Norbyvägen 18A, Uppsala, 08:55 (English)
Opponent
Supervisors
Funder
Swedish Research Council, 621-2011-4797
Available from: 2012-05-03 Created: 2012-05-03 Last updated: 2012-05-03Bibliographically approved
2. Melanization and Hemocyte Homeostasis  in the Freshwater Crayfish, Pacifastacus leniusculus
Open this publication in new window or tab >>Melanization and Hemocyte Homeostasis  in the Freshwater Crayfish, Pacifastacus leniusculus
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Blood cells or hemocytes play important roles in immunity. They are a major source of many immune-related molecules such as antibodies in adaptive immunity of vertebrates and prophenoloxidase (proPO) in invertebrates. In the crayfish Pacifastacus leniusculus, the proPO-system has been reported to be an important component of immune responses against microorganisms. In this study, several mutant strains of Aeromonas hydrophila were used to reveal that LPS (lipopolysaccharide) is an important factor for the pathogenicity of A. hydrophila, strongly inducing the proPO system and melanization. This proPO activating system is a multistep process, which has to be tightly controlled to avoid the harmful side effects of toxic intermediates. Many regulating factors have been reported to fine-tune the proPO-system. In this study, the cleavage of caspase-1-like activity was shown to be a novel negative regulator of PO activity in crayfish. Moreover, the fragments obtained by cleavage of proPO by the proPO-activating enzyme and caspase-1-like protein increased bacterial clearance. Thus, the peptides generated also have important biological functions.

In addition to being a source of immune proteins, hemocytes also participate in phagocytosis, encapsulation, and nodulation. An infection normally causes a reduction of hemocyte numbers. Consequently, hemocyte homeostasis is important for maintaining appropriate hemocyte numbers in the circulation of the animal. This study shows that the reactive oxygen species level in the anterior proliferation center of crayfish hematopoietic tissue (HPT), together with cell proliferation, was increased during infection. Pl-β-thymosins were proposed to be involved in hemocyte homeostasis by increasing stem cell migration and thus increasing the circulating hemocyte number. Crayfish hemocyte numbers, as well astakine (Ast1 and Ast2) expression in hemocytes and HPT, were previously shown to be under circadian regulation. Here, we show that Ast1, Ast2, and proPO exhibit rhythmic expression in the crayfish brain similarly to their orthologs, prokineticin 1, prokineticin 2 and tyrosinase, respectively, in the zebrafish brain. Tyrosinase expression was detected in zebrafish brain cells while PO-positive cells were identified as hemocytes that had infiltrated into the crayfish brain. Therefore, this information suggests a close relationship between crayfish hemocytes and the crayfish brain as well as vertebrate neurons.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 48 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1086
Keyword
melanization, prophenoloxidase, caspase, hematopoiesis, thymosin, astakine, circadian rhythm, reactive oxygen species, tyrosinase, prokineticin
National Category
Immunology
Identifiers
urn:nbn:se:uu:diva-209209 (URN)978-91-554-8774-4 (ISBN)
Public defence
2013-11-28, Lindahlssalen, EBC, Norbyvägen 18A, Uppsala, 10:00 (English)
Opponent
Supervisors
Available from: 2013-11-06 Created: 2013-10-15 Last updated: 2016-05-09

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Noonin, ChadanatJiravanichpaisal, PikulSöderhäll, IreneSöderhäll, Kenneth

Search in DiVA

By author/editor
Noonin, ChadanatJiravanichpaisal, PikulSöderhäll, IreneSöderhäll, Kenneth
By organisation
Comparative Physiology
In the same journal
PLoS ONE
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 489 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf