Riikka Ihalin
PhD
Biochemistry riihalin@utu.fi Tykistökatu 6 Turku Office: 6068 ORCID identifier: https://orcid.org/0000-0003-4118-0370 |
Areas of expertise
Oral microbiology; biofilms; Aggregatibacter actinomycetemcomitans; interkingdom signalling; molecular microbiology
Oral microbiology; biofilms; Aggregatibacter actinomycetemcomitans; interkingdom signalling; molecular microbiology
Research
Background
In natural environment, bacteria form communities, biofilms, on
surfaces. In biofilms, bacteria are more resistant than their planktonic
forms to antimicrobials and host defense factors. Reasons for biofilm
resistance to external forces include a protective extracellular matrix
and formation of non-dividing persister cells. In humans, bacterial
biofilms cause chronic infections. One of common biofilm diseases in
humans is periodontitis, a persistent multispecies infection triggering
chronic inflammation in tooth-supporting tissues. Periodontitis is
characterized by active and less active phases in inflammation and
tissue destruction suggesting that there might be certain type of
pathogen-host crosstalk. It has been suggested that bacteria growing in
biofilms could exploit proinflammatory cytokines produced by the host.
Thus cytokine network aimed to enhance the clearance of pathogens might
actually promote bacterial survival in protective biofilm.
surfaces. In biofilms, bacteria are more resistant than their planktonic
forms to antimicrobials and host defense factors. Reasons for biofilm
resistance to external forces include a protective extracellular matrix
and formation of non-dividing persister cells. In humans, bacterial
biofilms cause chronic infections. One of common biofilm diseases in
humans is periodontitis, a persistent multispecies infection triggering
chronic inflammation in tooth-supporting tissues. Periodontitis is
characterized by active and less active phases in inflammation and
tissue destruction suggesting that there might be certain type of
pathogen-host crosstalk. It has been suggested that bacteria growing in
biofilms could exploit proinflammatory cytokines produced by the host.
Thus cytokine network aimed to enhance the clearance of pathogens might
actually promote bacterial survival in protective biofilm.
Research
Our research is focused on studying biofilm-host interaction in chronic infection, periodontitis. We use Aggregatibacter actinomycetemcomitans (Aa),
a major pathogen in aggressive periodontitis, as model bacterium. In
particular we are interested how the outer membrane proteins are
involved in sensing the host response in inflammation. The research
include molecular- and structural biology methods, flow cytometry and
electron microscopy. In addition, we study the
biofilm-host interaction by using cell culture model which mimics the gingival tissue.
a major pathogen in aggressive periodontitis, as model bacterium. In
particular we are interested how the outer membrane proteins are
involved in sensing the host response in inflammation. The research
include molecular- and structural biology methods, flow cytometry and
electron microscopy. In addition, we study the
biofilm-host interaction by using cell culture model which mimics the gingival tissue.
Publications
- Deletion of competence genes represses expression of genes associated with anaerobic respiration/metabolism in Aggregatibacter actinomycetemcomitans (2023)
- bioRxiv
(Other (O2)) - Pilus PilA of the naturally competent HACEK group pathogen Aggregatibacter actinomycetemcomitans stimulates human leukocytes and interacts with both DNA and proinflammatory cytokines (2022)
- Microbial Pathogenesis
(Refereed journal article or data article (A1)) - Satamalaiturin liikuntasaumojen välisen lohkon kantavien rakenteiden mitoitus (The structural design of the load-bearing structures of a Finnish pier) (2022) Ihalin Riikka
(Polytechnic thesis, Bachelor’s thesis (G1)) - Decreased temperature increases the expression of a disordered bacterial late embryogenesis abundant (LEA) protein that enhances natural transformation (2021)
- Virulence
(Refereed journal article or data article (A1)) - Dispersion from C^alpha or N^H: 4D experiments for backbone resonance assignment of intrinsically disordered proteins (2020)
- Journal of Biomolecular NMR
(Refereed journal article or data article (A1)) - Aggregatibacter actinomycetemcomitans Biofilm Reduces Gingival Epithelial Cell Keratin Expression in an Organotypic Gingival Tissue Culture Model (2019)
- Pathogens
(Refereed journal article or data article (A1)) - Aggregatibacter actinomycetemcomitans LPS binds human interleukin-8 (2019)
- Journal of Oral Microbiology
(Refereed journal article or data article (A1)) - Transcriptomic Analysis of Aggregatibacter actinomycetemcomitans Core and Accessory Genes in Different Growth Conditions (2019)
- Pathogens
(Refereed journal article or data article (A1)) - Virulence and Pathogenicity Properties of Aggregatibacter actinomycetemcomitans (2019)
- Pathogens
(Refereed review article in scientific journal (A2)) - Interactions between the Aggregatibacter actinomycetemcomitans secretin HofQ and host cytokines indicate a link between natural competence and interleukin-8 uptake (2018)
- Virulence
(Refereed journal article or data article (A1)) - Peptidoglycan-associated lipoprotein of Aggregatibacter actinomycetemcomitans induces apoptosis and production of proinflammatory cytokines via TLR2 in murine macrophages RAW 264.7 in vitro (2018)
- Journal of Oral Microbiology
(Refereed journal article or data article (A1)) - Phosphorylcholine is located in Aggregatibacter actinomycetemcomitans fimbrial protein Flp 1 (2018)
- Medical Microbiology and Immunology
(Refereed journal article or data article (A1)) - A novel intrinsically disordered outer membrane lipoprotein of Aggregatibacter actinomycetemcomitans binds various cytokines and plays a role in biofilm response to interleukin-1β and interleukin-8 (2017)
- Virulence
(Refereed journal article or data article (A1)) - Functional and structural characteristics of bacterial proteins that bind host cytokines (2017)
- Virulence
(Refereed review article in scientific journal (A2)) - Miscellaneous IL-1β Binding Proteins of Aggregatibacter actinomycetemcomitans (2017) Moonlighting Proteins: Novel Virulence Factors in Bacterial Infections Riikka Ihalin
(Refereed article in compilation book (A3)) - Suun bakteeri aistii isäntänsä tulehdustilaa (2014)
- Suuhygienisti
(Article in trade journal or blog post (D1)) - Environmental stimuli shape biofilm formation and the virulence of periodontal pathogens (2013)
- International Journal of Molecular Sciences
(Refereed journal article or data article (A1)) - Identification of a Novel Bacterial Outer Membrane Interleukin-1B-Binding Protein from Aggregatibacter actinomycetemcomitans (2013)
- PLoS ONE
(Refereed journal article or data article (A1)) - Effects of Xylitol on Xylitol-Sensitive Versus Xylitol-Resistant Streptococcus mutans Strains in a Three-Species in Vitro Biofilm (2012)
- Current Microbiology
(Refereed journal article or data article (A1)) - Host-bacteria crosstalk at the dentogingival junction. (2012)
- International Journal of Dentistry
(Refereed review article in scientific journal (A2))