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
Stable transfection of the diplomonad parasite Spironucleus salmonicida
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Cell and Molecular Biology, Microbiology.
2012 (English)In: Eukaryotic Cell, ISSN 1535-9778, E-ISSN 1535-9786, Vol. 11, no 11, 1353-1361 p.Article in journal (Refereed) Published
Abstract [en]

Eukaryotic microbes are highly diverse and many lineages remain poorly studied. One such lineage, the diplomonads, a group of binucleate heterotrophic flagellates, has mainly been studied due to the impact of Giardia intestinalis, an intestinal, diarrhea-causing parasite in humans and animals. Here we describe the development of a stable transfection system for use in Spironucleus salmonicida, a diplomonad casuing systemic spironucleosis in salmonid fish. We designed vectors in cassette format carrying epitope tags for localization (3xHA, 2xOLLAS, 3xMYC) and purification of proteins (2xStrepII-FLAG or SBP-GST) under the control of native or constitutive promoters. Three selectable markers, puromycin acetyltransferase (pac), blasticidin S-deaminase (bsr) or neomycin phosphotransferase (nptII) were successfully applied for generation of stable transfectants. Site-specific integration on the S. salmonicida chromosome was shown to be possible using the bsr resistance gene. We epitope-tagged six proteins and confirmed their expression by Western Blot. Next, we demonstrated the utility of these vectors by recording the sub-cellular localizations of the six proteins by laser scanning confocal microscopy. Finally, we describe the creation of a S. salmonicida double transfectant suitable for co-localization studies. The transfection system described herein and the imminent completion of the S. salmonicida genome will make it possible to use comparative genomics as an investigative tool to explore specific as well as general diplomonad traits, benefiting research on both Giardia and Spironucleus.

Place, publisher, year, edition, pages
2012. Vol. 11, no 11, 1353-1361 p.
National Category
Microbiology Cell Biology
Research subject
Biology with specialization in Microbiology; Biology with specialization in Molecular Cell Biology
Identifiers
URN: urn:nbn:se:uu:diva-182827DOI: 10.1128/EC.00179-12ISI: 000310566400006PubMedID: 22983987OAI: oai:DiVA.org:uu-182827DiVA: diva2:560951
Available from: 2012-10-16 Created: 2012-10-16 Last updated: 2017-12-07Bibliographically approved
In thesis
1. Hidden Diversity Revealed: Genomic, Transcriptomic and Functional Studies of Diplomonads
Open this publication in new window or tab >>Hidden Diversity Revealed: Genomic, Transcriptomic and Functional Studies of Diplomonads
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The diplomonads are a diverse group of eukaryotic microbes found in oxygen limited environments such as the intestine of animals were they may cause severe disease. Among them, the prominent human parasite Giardia intestinalis non-invasively colonizes the small intestine of humans and animals where it induces the gastrointestinal disease giardiasis. Two of the eight genetic groups of G. intestinalis, assemblage A and B, are known to infect humans and have zoonotic potential. At the start of project, genome scale data from assemblage B-H was either sparse or entirely missing.

In this thesis, genome sequencing was performed on the assemblage B isolate GS (Paper I) and the P15 isolate (Paper III) of the hoofed-animals specific assemblage E to investigate the underlying components of phenotypic diversity in Giardia. Comparisons to assemblage A isolate WB revealed large genomic differences; entirely different repertoires of surface antigens, genome rearrangements and isolate specific coding sequences of potential bacterial origin. We established that genomic differences are also manifested at the transcriptome level (Paper VIII). In a follow up analysis (Paper IV) we concluded that the Giardia assemblages are largely reproductively isolated. The large genomic differences observed between Giardia isolates can explain the phenotypic diversity of giardiasis.

The adaptation of diplomonads was further studied in Spironucleus barkhanus (Paper II), a fish commensal of grayling, that is closely related to the fish pathogen Spironucleus salmonicida, causative agent of systemic spironucleosis in salmonid fish. We identified substantial genomic differences in the form of divergent genome size, primary sequence divergence and evidence of allelic sequence heterozygosity, a feature not seen in S. salmonicida.

We devised a transfection system for S. salmonicida (Paper VI) and applied it to the study of the mitochondrial remnant organelle (Paper VII). Our analyses showed that S. salmonicida harbor a hydrogenosome, an organelle with more metabolic capabilities than the mitosome of Giardia. Phylogenetic reconstructions of key hydrogenosomal enzymes showed an ancient origin, indicating a common origin to the hydrogenosome in parabasilids and diplomonads.

In conclusion, the thesis has provided important insights into the adaptation of diplomonads in the present and the distant past, revealing hidden diversity.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 104 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 990
Keyword
Giardia intestinalis, Spironucleus salmonicida, Spironucleus barkhanus, intestinal parasite, hydrogenosome, mitosome, lateral gene transfer, horizontal gene transfer, diplomonad, metamonad, sexual recombination, transfection, protein complex purification
National Category
Microbiology Evolutionary Biology Infectious Medicine
Research subject
Biology with specialization in Evolutionary Organismal Biology; Biology with specialization in Microbiology; Biology with specialization in Molecular Biology; Biology with specialization in Molecular Evolution
Identifiers
urn:nbn:se:uu:diva-182831 (URN)978-91-554-8520-7 (ISBN)
Public defence
2012-12-14, B22, Biomedicinskt centrum (BMC), Husargatan 3, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2012-11-22 Created: 2012-10-16 Last updated: 2013-02-11Bibliographically approved
2. Comparative Cell Biology in Diplomonads
Open this publication in new window or tab >>Comparative Cell Biology in Diplomonads
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The diplomonads are a diverse group of eukaryotic flagellates found in microaerophilic and anaerobic environments. The most studied diplomonad is the intestinal parasite Giardia intestinalis, which infects a variety of mammals and cause diarrheal disease. Less is known about Spironucleus salmonicida, a parasite of salmonid fish, known to cause systemic infections with high mortality.

We created a transfection system for S. salmonicida to study cellular functions and virulence in detail (Paper I). The system was applied to explore the mitochondrion-related organelle (MRO) in S. salmonicida. We showed that S. salmonicida possesses a hydrogenosome (Paper II) with a higher metabolic capacity than the corresponding MRO of Giardia, the mitosome. Evolutionary analysis of key hydrogenosomal proteins showed ancient origin, indicating their presence in the ancestral diplomonad and subsequent loss in Giardia. Annexins are of evolutionary interest since these proteins are found across all kingdoms. Annexin-like proteins are intriguingly expanded into multigene families in Giardia and Spironucleus. The annexins of S. salmonicida were characterized (Paper III) with distinct localizations to various cellular structures, including a putative adhesion structure anterior in the cell.

The disease-causing Giardia trophozoites differentiate into infectious cysts, a process essential for transmission and virulence of the parasite. Cysts are often spread via contaminated water and exposed to environmental stressors, such as UV irradiation. We studied the survival and transcriptional response to this stress factor (Paper IV) and results showed the importance of active DNA replication machinery for parasite survival after DNA damage. In addition, we studied transcriptional changes along the trajectory of encystation (Paper V), which revealed a coordinated cascade of gene regulation. This was observed for the entire transcriptome as well as putative regulators. Large transcriptional changes appeared late in the process with the majority of differentially regulated genes encoding hypothetical proteins. We studied the localizations of several of these to gain information of their possible function.

To conclude, the diplomonads are complex eukaryotic microbes with cellular processes adjusted to match their life styles. The work in this thesis has provided insight of their adaptations, differences and similarities, but also new interesting leads for future studies of diplomonad biology and virulence. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2015. 84 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1303
Keyword
Giardia intestinalis, Spironucleus salmonicida, intestinal parasite, hydrogenosome, encystation, gene regulation, transfection, diplomonad, antigenic variation, annexin
National Category
Microbiology
Identifiers
urn:nbn:se:uu:diva-264541 (URN)978-91-554-9374-5 (ISBN)
Public defence
2015-12-04, A1:111a, BMC, Husargatan 3, Uppsala, 09:15 (English)
Opponent
Supervisors
Available from: 2015-11-12 Created: 2015-10-14 Last updated: 2015-11-13

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Authority records BETA

Jerlström-Hultqvist, JonEinarsson, ElinSvärd, Staffan G

Search in DiVA

By author/editor
Jerlström-Hultqvist, JonEinarsson, ElinSvärd, Staffan G
By organisation
Microbiology
In the same journal
Eukaryotic Cell
MicrobiologyCell Biology

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 400 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