Malmö University Publications
Change search
Refine search result
1 - 3 of 3
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Labecka, Nikol
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden.
    Szczepanczyk, Michal
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Mojumdar, Enamul Haque
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden; CR Competence AB, Box 124, 22100 Lund, Sweden.
    Sparr, Emma
    Division of Physical Chemistry, Chemistry Department, Lund University, SE-221 00 Lund, Sweden.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Unraveling UVB effects: Catalase activity and molecular alterations in the stratum corneum.2024In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 666, p. 176-188, article id S0021-9797(24)00709-4Article in journal (Refereed)
    Abstract [en]

    AIM: Ultraviolet B (UVB) radiation can compromise the functionality of the skin barrier through various mechanisms. We hypothesize that UVB induce photochemical alterations in the components of the outermost layer of the skin, known as the stratum corneum (SC), and modulate its antioxidative defense mechanisms. Catalase is a well-known antioxidative enzyme found in the SC where it acts to scavenge reactive oxygen species. However, a detailed characterization of acute UVB exposure on the activity of native catalase in the SC is lacking. Moreover, the effects of UVB irradiation on the molecular dynamics and organization of the SC keratin and lipid components remain unclear. Thus, the aim of this work is to characterize consequences of UVB exposure on the structural and antioxidative properties of catalase, as well as on the molecular and global properties of the SC matrix surrounding the enzyme.

    EXPERIMENTS: The effect of UVB irradiation on the catalase function is investigated by chronoamperometry with a skin covered oxygen electrode, which probes the activity of native catalase in the SC matrix. Circular dichroism is used to explore changes of the catalase secondary structure, and gel electrophoresis is used to detect fragmentation of the enzyme following the UVB exposure. UVB induced alterations of the SC molecular dynamics and structural features of the SC barrier, as well as its water sorption behavior, are investigated by a complementary set of techniques, including natural abundance 13C polarization transfer solid-state NMR, wide-angle X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, and dynamic vapor sorption microbalance.

    FINDINGS: The findings show that UVB exposure impairs the antioxidative function of catalase by deactivating both native catalase in the SC matrix and lyophilized catalase. However, UVB radiation does not alter the secondary structure of the catalase nor induce any observable enzyme fragmentation, which otherwise could explain deactivation of its function. NMR measurements on SC samples show a subtle increase in the molecular mobility of the terminal segments of the SC lipids, accompanied by a decrease in the mobility of lipid chain trans-gauche conformers after high doses of UVB exposure. At the same time, the NMR data suggest increased rigidity of the polypeptide backbone of the keratin filaments, while the molecular mobility of amino acid residues in random coil domains of keratin remain unaffected by UVB irradiation. The FTIR data show a consistent decrease in absorbance associated with lipid bond vibrations, relative to the main protein bands. Collectively, the NMR and FTIR data suggest a small modification in the composition of fluid and solid phases of the SC lipid and protein components after UVB exposure, unrelated to the hydration capacity of the SC tissue. To conclude, UVB deactivation of catalase is anticipated to elevate oxidative stress of the SC, which, when coupled with subtle changes in the molecular characteristics of the SC, may compromise the overall skin health and elevate the likelihood of developing skin disorders.

    Download full text (pdf)
    fulltext
  • 2.
    Szczepanczyk, Michal
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Paul, Lea
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Comparison of Oxygen Electrode Chronoamperometry and Spectrophotometry for Determination of Catalase Activity2023In: Oxygen, E-ISSN 2673-9801, Vol. 3, no 1, p. 77-89Article in journal (Refereed)
    Abstract [en]

    Catalase is a key antioxidative enzyme, and a deficiency or malfunction of catalase is hypothesized to be related to various diseases. To investigate catalase activity, it is important to use reliable methods and experimental protocols enabling consistent fallouts. One major problem, however, is that the activity values obtained with different techniques and procedures can vary to a large extent. The aim of this work was to identify experimental conditions that provide similar catalase activity values with two different methods based on either spectrophotometry or chronoam- perometry. The investigated parameters include the concentration of catalase and its substrate (H2O2), as well as the effect of deoxygenation of the catalase medium by nitrogen (N2). Within the frame of investigated conditions, we show that spectrophotometry is strongly affected by the catalase concen- tration, whereas chronoamperometry is shown to be more dependent on the substrate concentration. Deoxygenation leads to elevated catalase activity values in the case of chronoamperometry, whereas it shows no influence on the results obtained with spectrophotometry. In particular, in the case of low substrate concentrations (i.e., low catalase reaction rates), higher and more accurate results are obtained with deoxygenation in the case of chronoamperometry measurements due to minimized oxygen escape. The effect of deoxygenation, giving rise to elevated catalase activity values, however, is not statistically significant at high substrate concentrations, implying that the protocol can be sim- plified by excluding this step as long as the other parameters are optimized. Finally, by comparing the two methods at different experimental conditions, we identified protocols resulting in similar results, i.e., 10 mM H2O2 and catalase activity of 4–5 U/mL. Based on this work, improved consistency of catalase activity data obtained with different methodologies and in different labs is expected.

    Download full text (pdf)
    fulltext
  • 3.
    Szczepanczyk, Michal
    et al.
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces. Simris Alg AB, S-27650 Hammenhög, Sweden..
    Ruzgas, Tautgirdas
    Malmö University, Biofilms Research Center for Biointerfaces. Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV).
    Gullfot, Fredrika
    Simris Alg AB, S-27650 Hammenhog, Sweden..
    Gustafsson, Anna
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Björklund, Sebastian
    Malmö University, Faculty of Health and Society (HS), Department of Biomedical Science (BMV). Malmö University, Biofilms Research Center for Biointerfaces.
    Catalase Activity in Keratinocytes, Stratum Corneum, and Defatted Algae Biomass as a Potential Skin Care Ingredient2021In: Biomedicines, E-ISSN 2227-9059, Vol. 9, no 12, article id 1868Article in journal (Refereed)
    Abstract [en]

    The generation of reactive oxygen species presents a destructive challenge for the skin organ and there is a clear need to advance skin care formulations aiming at alleviating oxidative stress. The aim of this work was to characterize the activity of the antioxidative enzyme catalase in keratinocytes and in the skin barrier (i.e., the stratum corneum). Further, the goal was to compare the activity levels with the corresponding catalase activity found in defatted algae biomass, which may serve as a source of antioxidative enzymes, as well as other beneficial algae-derived molecules, to be employed in skin care products. For this, an oxygen electrode-based method was employed to determine the catalase activity and the apparent kinetic parameters for purified catalase, as well as catalase naturally present in HaCaT keratinocytes, excised stratum corneum samples collected from pig ears with various amounts of melanin, and defatted algae biomass from the diatom Phaeodactylum tricornutum. Taken together, this work illustrates the versatility of the oxygen electrode-based method for characterizing catalase function in samples with a high degree of complexity and enables the assessment of sample treatment protocols and comparisons between different biological systems related to the skin organ or algae-derived materials as a potential source of skin care ingredients for combating oxidative stress.

1 - 3 of 3
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • 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