Biomedical subjects

Flemming Jessen

Publications and source records attributed to Flemming Jessen.

6 recordsLinked to original sources

PubMed2006

Identification of carbonylated protein in frozen rainbow trout (Oncorhynchus mykiss) fillets and development of protein oxidation during frozen storage.

Frozen storage of fish is known to enhance lipid oxidation, resulting in the development of an unpleasant rancid taste and odor. Frozen storage of fish is also known to reduce protein solubility, and proteins are expected to be oxidatively modified; however, these oxidative mechanisms are poorly understood. Generally, protein oxidation leads to a wide range of modifications; the most studied being the formation of carbonyl groups. The present work shows, by UV spectrophometric determination of protein carbonyl groups in rainbow trout muscle, that storage at -20 degrees C resulted in a 2-fold increase in protein carbonylation compared to storage at -30 or -80 degrees C. Furthermore, low-salt-soluble proteins in fish that were either fresh or stored for 3 years at -80 degrees C were found to have similar extents of carbonylation. Proteome analysis and two-dimensional immunoblotting of rainbow trout low-salt- and high-salt-soluble proteins gave a detailed description of the protein carbonylation pattern. Several carbonylated proteins were identified by LC-MS/MS, such as nucleoside diphosphate kinase, adenylate kinase, pyruvate kinase, actin, creatine kinase, tropomyosin, myosin light chains 1 and 2, and myosin heavy chain. Furthermore, the results showed a reduced solubility of nucleoside diphosphate kinase in fish stored at -20 degrees C for 2 years compared to fish stored at -80 degrees C. It was observed that low-abundant proteins could be relatively more carbonylated than high-abundant proteins, thereby indicating that some proteins are more susceptible to oxidation than others, due to either their cellular localization, amino acid sequence, or biochemical function.

Electrophoresis, Gel, Two-Dimensional↗

PubMed2006

Changes in cod muscle proteins during frozen storage revealed by proteome analysis and multivariate data analysis.

Multivariate data analysis has been combined with proteomics to enhance the recovery of information from 2-DE of cod muscle proteins during different storage conditions. Proteins were extracted according to 11 different storage conditions and samples were resolved by 2-DE. Data generated by 2-DE was subjected to principal component analysis (PCA) and discriminant partial least squares regression (DPLSR). Applying PCA to 2-DE data revealed the samples to form groups according to frozen storage time, whereas differences due to different storage temperatures or chilled storage in modified atmosphere packing did not lead to distinct changes in protein pattern. Applying DPLSR to the 2-DE data enabled the selection of protein spots critical for differentiation between 3 and 6 months frozen storage with 12 months frozen storage. Some of these protein spots have been identified by MS/MS, revealing myosin light chain 1, 2 and 3, triose-phosphate isomerase, glyceraldehyde-3-phosphate dehydrogenase, aldolase A and two alpha-actin fragments, and a nuclease diphosphate kinase B fragment to change in concentration, during frozen storage. Application of proteomics, multivariate data analysis and MS/MS to analyse protein changes in cod muscle proteins during storage has revealed new knowledge on the issue and enables a better understanding of biochemical processes occurring.

Electrophoresis, Gel, Two-Dimensional↗

PubMed2004

Two-dimensional gel electrophoresis detection of protein oxidation in fresh and tainted rainbow trout muscle.

Protein oxidation is evaluated in rainbow trout muscle by labeling protein carbonyls with 2,4-dinitrophenyl hydrazine (DNPH) followed by immunoblotting of proteins separated by SDS-PAGE or two-dimensional gel electrophoresis (2D-GE). The carbonylation level is accessed on proteins in a whole muscle homogenate or proteins soluble in a high-salt or low-salt buffer. Spoilage-related changes in carbonylation are followed in the high-salt-protein and low-salt-protein fractions by 2D immunoblotting, which reveals increases regarding total number and intensity of carbonylation in both protein fractions for fish kept at room temperature for 48 h. The major amount of carbonylated proteins is found among the high-salt-soluble proteins, and this protein fraction is also responsible for the biggest increase in carbonylation during fish tainting. The results give an estimate of the level of protein carbonylation in rainbow trout and reveal that oxidation increases for a distinct number of proteins during tainting.

Animals↗

PubMed2003

Proteome analysis elucidating post-mortem changes in cod (Gadus morhua) muscle proteins.

Proteome analysis was successfully applied to study the alterations in fish muscle proteins during ice storage. The processes occurring during post-mortem metabolism are known to lead to characteristic changes in the texture and taste of fish muscle. Endogenous proteases are anticipated to play the major role in these processes, although the exact mechanisms during fish meat tenderization have yet to be depicted. Protein changes in cod (Gadus morhua) muscle were followed during 8 days of storage. Within the partial proteome (pI 3.5-8.0, MW 13-35 kDa) significant changes were found in 11 protein spots. In nine protein spots the intensity increased, and for eight of these the increases were significant (p < 0.05) within the first 2 h post-mortem. In contrast, two protein spots decreasing in intensity showed significant (p < 0.03) changes after 8 days, thereby indicating that in the fish muscle different biochemical processes are involved in the protein changes observed post-mortem.

Adenosine Triphosphate↗

PubMed2002

Temperature and Ca(2+)-dependence of the sarcoplasmic reticulum Ca(2+)-ATPase in haddock, salmon, rainbow trout and zebra cichlid.

Temperature dependence of Ca(2+)-ATPase from the sarcoplasmic reticulum (SR) in rabbit muscle has been widely studied, and it is generally accepted that a break point in Arrhenius plot exist at approximately 20 degrees C. Whether the break point arises as a result of temperature dependent changes in the enzyme or its membrane lipid environment is still a matter of discussion. In this study we compared the temperature dependence and Ca(2+)-dependence of SR Ca(2+)-ATPase in haddock (Melanogrammus aeglefinus), salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss) and zebra cichlid (Cichlasoma nigrofasciatum). The Arrhenius plot of zebra cichlid showed a break point at 20 degrees C, and the haddock Arrhenius plot was non-linear with pronounced changes in slope in the temperature area, 6-14 degrees C. In Arrhenius plot from both salmon and rainbow trout a plateau exists with an almost constant SR Ca(2+)-ATPase activity. The temperature range of the plateau was 14-21 and 18-25 degrees C in salmon and rainbow trout, respectively. Ca(2+)-dependence in the four different fish species investigated was very similar with half maximal activation (K(0.5)) between 0.2 and 0.6 micro M and half maximal inhibition (I(0.5)) between 60 and 250 micro M. Results indicated that interaction between SR Ca(2+)-ATPase and its lipid environment may play an important role for the different Arrhenius plot of the different types of fish species investigated.

Animals↗

PubMed2002

Extracting information from two-dimensional electrophoresis gels by partial least squares regression.

Two-dimensional gel electrophoresis (2-DE) produces large amounts of data and extraction of relevant information from these data demands a cautious and time consuming process of spot pattern matching between gels. The classical approach of data analysis is to detect protein markers that appear or disappear depending on the experimental conditions. Such biomarkers are found by comparing the relative volumes of individual spots in the individual gels. Multivariate statistical analysis and modelling of 2-DE data for comparison and classification is an alternative approach utilising the combination of all proteins/spots in the gels. In the present study it is demonstrated how information can be extracted by multivariate data analysis. The strategy is based on partial least squares regression followed by variable selection to find proteins that individually or in combination with other proteins vary informatively in relation to the experimental conditions. Finding of such coherent protein patterns leads to identification of potential relations between the involved proteins, and will be useful for focusing further investigation of proteins that relate to the chosen experimental conditions.

Electrophoresis, Gel, Two-Dimensional↗