| 1. |
- Berntsson, Elina, et al.
(författare)
-
Lithium ions display weak interaction with amyloid-beta (Aβ) peptides and have minor effects on their aggregation
- 2021
-
Ingår i: Acta Biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 68:2, s. 169-179
-
Tidskriftsartikel (refereegranskat)abstract
- Alzheimer’s disease (AD) is an incurable disease and the main cause of age-related dementia worldwide, despite decades of research. Treatment of AD with lithium (Li) has shown promising results, but the underlying mechanism is unclear. The pathological hallmark of AD brains is deposition of amyloid plaques, consisting mainly of amyloid-β (Aβ) peptides aggregated into amyloid fibrils. The plaques contain also metal ions of e.g. Cu, Fe, and Zn, and such ions are known to interact with Aβ peptides and modulate their aggregation and toxicity. The interactions between Aβ peptides and Li+ions have however not been well investigated. Here, we use a range of biophysical techniques to characterize in vitro interactions between Aβ peptides and Li+ions. We show that Li+ions display weak and non-specific interactions with Aβ peptides, and have minor effects on Aβ aggregation. These results indicate that possible beneficial effects of Li on AD pathology are not likely caused by direct interactions between Aβ peptides and Li+ions.
|
|
| 2. |
- Doan, Thuy, et al.
(författare)
-
Biochemical characteristics of AtFAR2, a fatty acid reductase from Arabidopsis thaliana that reduces fatty acyl-CoA and -ACP substrates into fatty alcohols
- 2016
-
Ingår i: Acta Biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 63, s. 565-570
-
Tidskriftsartikel (refereegranskat)abstract
- Fatty alcohols and derivatives are important for proper deposition of a functional pollen wall. Mutations in specific genes encoding fatty acid reductases (FAR) responsible for fatty alcohol production cause abnormal development of pollen. A disrupted AtFAR2 (MS2) gene in Arabidopsis thaliana results in pollen developing an abnormal exine layer and a reduced fertility phenotype. AtFAR2 has been shown to be targeted to chloroplasts and in a purified form to be specific for acyl-ACP substrates. Here, we present data on the in vitro and in planta characterizations of AtFAR2 from A. thaliana and show that this enzyme has the ability to use both, C16:0-ACPand C16:0-CoA, as substrates to produce C16:0-alcohol. Our results further show that AtFAR2 is highly similar in properties and substrate specificity to AtFAR6 for which in vitro data has been published, and which is also a chloroplast localized enzyme. This suggests that although AtFAR2 is the major enzyme responsible for exine layer functionality, AtFAR6 might provide functional redundancy to AtFAR2.
|
|
| 3. |
- Gabig-Ciminska, Magdalena, et al.
(författare)
-
An introduction to DNA chips : principles, technology, applications and analysis
- 2001
-
Ingår i: Acta Biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 48:3, s. 615-622
-
Forskningsöversikt (refereegranskat)abstract
- This review describes the recently developed GeneChip technology that provides efficient access to genetic information using miniaturised, high-density arrays of DNA or oligonucleotide probes. Such microarrays are powerful tools to study the molecular basis of interactions on a scale that would lie impossible using conventional analysis. The recent development of the microarray technology has greatly accelerated the investigation of gene regulation. Arrays are mostly used to identify which genes are turned on or off in a cell or tissue, and also, to evaluate the extent of a gene's expression under various conditions. Indeed, this technology has been successfully applied to investigate simultaneous expression of many thousands of genes and to the detection of mutations or polymorphisms, as well as for their mapping and sequencing.
|
|
| 4. |
- Gielnik, Maciej, et al.
(författare)
-
The engineered peptide construct NCAM1-Aβ inhibits fibrillization of the human prion protein (PrP)
- 2022
-
Ingår i: Acta Biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 69:1, s. 257-261
-
Tidskriftsartikel (refereegranskat)abstract
- In prion diseases, the prion protein (PrP) becomes misfolded and forms fibrillar aggregates that are responsible for prion infectivity and pathology. So far, no drug or treatment procedures have been approved for prion disease treatment. We have previously shown that engineered cell-penetrating peptide constructs can reduce the amount of prion aggregates in infected cells. However, the molecular mechanism underlying this effect is unknown. Here, we use atomic force microscopy (AFM) imaging to show that the amyloid aggregation and fibrillization of the human PrP protein can be inhibited by equimolar amounts of the 25 residues long engineered peptide construct NCAM1-Aβ.
|
|
| 5. |
- Madeja, Z, et al.
(författare)
-
New cationic polyprenyl derivative proposed as a lipofecting agent
- 2007
-
Ingår i: Acta biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 54, s. 873-876
-
Tidskriftsartikel (refereegranskat)abstract
- Cationic linear poly-cis-isoprenoid prepared from natural plant polyprenol in a mixture with dioleyl phosphatidylethanolamine was found to be an effective lipofection agent for eukaryotic cells. The transfecting activity is related to the poly-cis structure of the polyprenyl chain.
|
|
| 6. |
- Slesak, Ireneusz, et al.
(författare)
-
The role of hydrogen peroxide in regulation of plant metabolism and cellular signalling in response to environmental stresses
- 2007
-
Ingår i: Acta Biochimica Polonica. - 0001-527X .- 1734-154X. ; 54:1, s. 39-50
-
Tidskriftsartikel (refereegranskat)abstract
- Hydrogen peroxide (H2O2) is produced predominantly in plant cells during photosynthesis and photorespiration, and to a lesser extent, in respiration processes. It is the most stable of the so-called reactive oxygen species (ROS), and therefore plays a crucial role as a signalling molecule in various physiological processes. Intra- and intercellular levels of H2O2 increase during environmental stresses. Hydrogen peroxide interacts with thiol-containing proteins and activates different signalling pathways as well as transcription factors, which in turn regulate gene expression and cell-cycle processes. Genetic systems controlling cellular redox homeostasis and H2O2 signalling are discussed. In addition to photosynthetic and respiratory metabolism, the extracellular matrix (ECM) plays an important role in the generation of H2O2, which regulates plant growth, development, acclimatory and defence responses. During various environmental stresses the highest levels of H2O2 are observed in the leaf veins. Most of our knowledge about H2O2 in plants has been obtained from obligate C-3 plants. The potential role of H2O2 in the photosynthetic mode of carbon assimilation, such as C-4 metabolism and CAM (Crassulacean acid metabolism) is discussed. We speculate that early in the evolution of oxygenic photosynthesis on Earth, H2O2 could have been involved in the evolution of modem photosystem II.
|
|
| 7. |
- Smoluch, MT, et al.
(författare)
-
Nanospray mass spectrometry for identification of peptides. Application of a novel interface
- 1999
-
Ingår i: Acta biochimica Polonica. - : Polskie Towarzystwo Biochemiczne (Polish Biochemical Society). - 0001-527X .- 1734-154X. ; 46:2, s. 475-481
-
Tidskriftsartikel (refereegranskat)abstract
- Electrospray ionization mass spectrometry is a powerful tool for identification of biomolecules such as peptides, proteins, oligosaccharides and neurotransmitters. Recent development of the nanospray techniques, applied at ultralow flow-rates, allowed a sensitive analysis of compounds at femto/attomolar level. Here, we present application of a novel nanospray device for the analysis and fragmentation of peptides with high sensitivity on a sector instrument. The lowest applied flow-rate of the mobile phase was maintained at 50 nl/min with a sample load of 90 fmol. Nanospray also provided a complete analysis of 500 nl of the sample for over 10 min, including sequencing of as little as 40 pmol of a substance. Such analysis provides full structural information necessary to identify the molecules.
|
|
| 8. |
- Stoika, Rostyslav, et al.
(författare)
-
Potential role of transforming growth factor beta1 in drug resistance of tumor cells
- 2003
-
Ingår i: Acta Biochimica Polonica. - 0001-527X .- 1734-154X. ; 50:2, s. 497-508
-
Tidskriftsartikel (refereegranskat)abstract
- Acquired drug resistance of tumor cells is frequently observed in cancer patients undergoing chemotherapy. We studied murine leukemia L1210 cells sensitive and resistant to the cytotoxic action of cisplatin and showed that cisplatin-resistant leukemia cells were also refractory to TGF beta1-dependent growth inhibition and apoptosis. Addressing the question about the mechanisms responsible for the cross-resistance to cisplatin and TGF beta1, we found that cisplatin- and TGF beta1-resistant L1210 cells possessed a decreased expression of type I TGF beta1 receptor, while the expression of type II TGF beta1 receptor was not affected. Western blot analysis of Smad proteins 2, 3, 4, 6, and 7, which participate in signal transduction pathway down-stream of the TGF beta1 receptors, revealed an increased expression of Smad 6, inhibiting TGF beta1 action, only in cisplatin- and TGF beta1-resistant L1210 cells. TGF beta1 and especially the cytotoxic mistletoe agglutinin increased Smad 6 expression in TGF beta1-sensitive but not in TGF beta1-resistant L1210 cells. TGF beta1-resistant L1210 cells also differed from TGF beta1-sensitive cells by the lack of expression of the pro-apoptotic p53 protein and higher level of expression of the anti-apoptotic Bcl-2 protein. Thus, the described co-expression of tumor cell refractoriness to an anti-cancer drug and to the inhibitory cytokine TGF beta1 is accompanied by multiple changes in the TGF beta1 signal transduction pathway and in other regulatory systems of the target cells. Besides, we found that various anti-tumor drugs and cytotoxic plant lectins increased the level of TGF beta1 expression in both TGFbeta1-sensitive and -resistant L1210 cells. A hypothesis is proposed that TGFbeta1 can at least partly mediate the effect of cell-stressing agents and, thus, the development of TGF beta1 resistance may be responsible for the appearance of tumor cell refractoriness to the action of some anti-cancer drugs.
|
|
| 9. |
|
|
| 10. |
- Funa, Keiko, 1949, et al.
(författare)
-
Regulatory mechanisms for the expression and activity of platelet-derived growth factor receptor.
- 2003
-
Ingår i: Acta biochimica Polonica. - 0001-527X. ; 50:3, s. 647-58
-
Forskningsöversikt (refereegranskat)abstract
- PDGF is one of the most potent serum mitogens, and the signalling mechanism by way of its receptor tyrosine-kinase has been extensively studied since its first purification in 1979. The identification of homology between the simian sarcoma virus oncogene, v-sis, and the B-chain of PDGF, as well as the frequent over-expression of both the ligands and receptors in various tumours and stroma led to the proposal of the PDGF-mediated autocrine and paracrine hypothesis. Consistent with the important roles of PDGF in the growth and survival of cells, the expression and activity of PDGF receptors are tightly controlled by both positive and negative feedback mechanisms at different levels. The deregulation of the control system can result in serious pathological conditions such as chronic inflammation and tumours. Understanding the molecular mechanisms for the regulatory system and the signalling pathway of PDGF is essential in order to find effective therapies in the diseases where PDGF is involved.
|
|
| 11. |
- Grzonka, Zbigniew, et al.
(författare)
-
Structural studies of cysteine proteases and their inhibitors
- 2001
-
Ingår i: Acta Biochimica Polonica. - 0001-527X. ; 48:1, s. 1-20
-
Forskningsöversikt (refereegranskat)abstract
- Cysteine proteases (CPs) are responsible for many biochemical processes occurring in living organisms and they have been implicated in the development and progression of several diseases that involve abnormal protein turnover. The activity of CPs is regulated among others by their specific inhibitors: cystatins. The main aim of this review is to discuss the structure-activity relationships of cysteine proteases and cystatins, as well as of some synthetic inhibitors of cysteine proteases structurally based on the binding fragments of cystatins.
|
|
| 12. |
|
|
| 13. |
|
|
| 14. |
|
|
| 15. |
- Stachowiak, K, et al.
(författare)
-
Effect of antisense peptide binding on the dimerization of human cystatin C - gel electrophoresis and molecular modeling studies
- 2004
-
Ingår i: Acta Biochimica Polonica. - 0001-527X. ; 51:1, s. 153-160
-
Tidskriftsartikel (refereegranskat)abstract
- Human cystatin C (HCC) shows a tendency to dimerize. This process is particularly easy in the case of the L68Q HCC mutant and might lead to formation of amyloid deposits in brain arteries of young adults. Our purpose was to find ligands of monomeric HCC that can prevent its dimerization. Eleven antisense peptide ligands of monomeric HCC were designed and synthesized. The influence of these ligands on HCC dimerization was studied using gel electrophoresis and molecular modeling methods. The results suggest that all the designed peptides interact with monomeric HCC facilitating its dimerization rather than preventing it.
|
|
| 16. |
- Szymańska, Aneta, et al.
(författare)
-
Governing the monomer-dimer ratio of human cystatin C by single amino acid substitution in the hinge region
- 2009
-
Ingår i: Acta Biochimica Polonica. - 0001-527X. ; 56:3, s. 455-463
-
Tidskriftsartikel (refereegranskat)abstract
- Three dimensional domain swapping is one of the mechanisms involved in formation of insoluble aggregates of some amyloidogenic proteins. It has been proposed that proteins able to swap domains may share some common structural elements like conformationally constrained flexible turns/loops. We studied the role of loop L1 in the dimerization of human cystatin C using mutational analysis. Introduction of turn-favoring residues such as Asp or Asn into the loop sequence (in position 57) leads to a significant reduction of the dimer fraction in comparison with the wild type protein. On the other hand, introduction of a proline residue in position 57 leads to efficient dimer formation. Our results confirm the important role of the loop L1 in the dimerization process of human cystatin C and show that this process can be to some extent governed by single amino acid substitution.
|
|
| 17. |
|
|
