| 1. |
- Agbaje, Oluwatoosin B. A., et al.
(författare)
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Organic biopolymers of venus clams : Collagen-related matrix in the bivalve shells with crossed-lamellar ultrastructure
- 2021
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Ingår i: Biochemistry and biophysics reports. - : Elsevier. - 2405-5808. ; 26
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Tidskriftsartikel (refereegranskat)abstract
- Background: Biochemical studies and spectroscopic techniques have shown that chitin-silk fibroins are common in nacroprismatic bivalve shells. However, the nature of organic biopolymers in the less well studied shell architectures, such as crossed lamellar shells, remain unknown. Here, two venus shells, Callista disrupta and Callista kingii, with crossed lamellar ultrastructure have been studied.Methods: We employed thermal gravimetric analysis, optical-, confocal- and scanning electron-microscopes, gel-sodium dodecyl sulfate (gel-SDS), FTIR, ultra-performance liquid chromatography and high-performance anion-exchange chromatography system with pulsed amperometric detection to analyse organic macromolecules in the shells.Results: Thermal analysis showed a low concentration of organic macromolecules in C. disrupta (1.38 wt%) and in C. kingii (1.71 wt%). A combination of biochemical protocols, including Calcofluor White staining and FTIR spectroscopic assessment, indicate that amino-polysaccharide chitin together with proteins, are present in the organic scaffolding of the shells. Scanning electron microscope of insoluble acid biopolymer extracts as well as FTIR technique show that the hierarchical structural organizations of organic biopolymers consist collagen-related matrix. Our histochemical fixing and staining techniques reveal many discrete proteins and glycoproteins from soluble organic macromolecules on the gel-SDS. We show here 'singlet' and 'doublet' glycosaminoglycan bands that are far above 260 kDa.General significance/conclusions: The presence of collagen matrix in Callista shells shows promise for the new source of biomaterials. Most importantly, the structural organization of the proteinaceous motif is predominantly helical structures and not silk-fibroin unlike in nacreous bivalve shells.
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| 2. |
- Bankell, Elisabeth, et al.
(författare)
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The antimicrobial peptide LL-37 triggers release of apoptosis-inducing factor and shows direct effects on mitochondria
- 2022
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier BV. - 2405-5808. ; 29
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Tidskriftsartikel (refereegranskat)abstract
- The human antimicrobial peptide LL-37 permeabilizes the plasma membrane of host cells, but LL-37-induced direct effects on mitochondrial membrane permeability and function has not been reported. Here, we demonstrate that LL-37 is rapidly (within 20 min) internalized by human osteoblast-like MG63 cells, and that the peptide co-localizes with MitoTracker arguing for accumulation in mitochondria. Subcellular fractionation and Western blot disclose that stimulation with LL-37 (8 μM) for 2 h triggers release of the mitochondrial protein apoptosis-inducing factor (AIF) to the cytosol, whereas LL-37 causes no release of cytochrome C oxidase subunit IV of the inner mitochondrial membrane, suggesting that LL-37 affects mitochondrial membrane permeability in a specific manner. Next, we investigated release of AIF and cytochrome C from isolated mitochondria by measuring immunoreactivity by dot blot. The media of mitochondria treated with LL-37 (8 μM) for 2 h contained 50% more AIF and three times more cytochrome C than that of control mitochondria, showing that LL-37 promotes release of both AIF and cytochrome C. Moreover, in vesicles reflecting mitochondrial membrane lipid composition, LL-37 stimulates membrane permeabilization and release of tracer molecules. We conclude that LL-37 is rapidly internalized by MG63 cells and accumulates in mitochondria, and that the peptide triggers release of pro-apoptotic AIF and directly affects mitochondrial membrane structural properties.
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| 3. |
- Brown, Christian, et al.
(författare)
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The MIT domain of chitin synthase 1 from the oomycete Saprolegnia monoica interacts specifically with phosphatidic acid
- 2022
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier BV. - 2405-5808. ; 30
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Tidskriftsartikel (refereegranskat)abstract
- Chitin synthases are vital for growth in certain oomycetes as chitin is an essential component in the cell wall of these species. In Saprolegnia monoica, two chitin synthases have been found, and both contain a Microtubule Interacting and Trafficking (MIT) domain. The MIT domain has been implicated in lipid interaction, which in turn may be of significance for targeting of chitin synthases to the plasma membrane. In this work we have investigated the lipid interacting properties of the MIT domain from chitin synthase 1 in Saprolegnia monoica. We show by fluorescence spectroscopy techniques that the MIT domain interacts preferentially with phosphatidic acid (PA), while it does not interact with phosphatidylglycerol (PG) or phosphatidylcholine (PC). These results strongly suggest that the specific properties of PA are required for membrane interaction of the MIT domain. PA is negatively charged, binds basic side chains with high affinity and its small headgroup gives rise to membrane packing defects that enable intercalation of hydrophobic amino acids. We propose a mode of lipid interaction that involves a combination of basic amino acid residues and Trp residues that anchor the MIT domain specifically to bilayers that contain PA.
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| 6. |
- Ismail, Aram, et al.
(författare)
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Marmoset glutathione transferases with ketosteroid isomerase activity
- 2021
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier BV. - 2405-5808. ; 27
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Tidskriftsartikel (refereegranskat)abstract
- The common marmoset Callithrix jacchus encodes two glutathione transferase (GST) enzymes with ketosteroid double-bond isomerase activity. The most active enzyme is CjaGST A3-3 showing a specific activity with 5-androsten-3,17-dione (Delta(5)-AD) of 62.1 +/- 1.8 mu mol min(-1) mg(-1), and a k(cat) value of 261 +/- 49 s(-1). The second ketostemid isomerase CjaGST A1-1 has a 30-fold lower specific activity with Delta(5)-AD and a 37-fold lower k(cat) value. Thus, the marmoset CjaGST A3-3 would be the main contributor to the biosynthesis of the steroid hormones testosterone and progesterone, like the human ortholog HsaGST A3-3. Two residues differ in the H-site of the 91.4% sequence identical CjaGST A1-1 and CjaGST A3-3, and modeling of the structures suggests that the bulky phenyl ring of Phe111 in CjaGST A1-1 causes steric hindrance in the binding of the steroid substrate. Tributyltin acetate (IC50 =0.16 +/- 0.004 mu M) and ethacrynic acid (IC50 =3.3 +/- 0.2 mu M) were found to be potent inhibitors of CjaGST A3-3, as previously demonstrated with the human and equine orthologs.
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| 7. |
- Mazari, Aslam M. A., et al.
(författare)
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Drosophila GSTs display outstanding catalytic efficiencies with the environmental pollutants 2,4,6-trinitrotoluene and 2,4-dinitrotoluene
- 2016
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier BV. - 2405-5808. ; 5, s. 141-145
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Tidskriftsartikel (refereegranskat)abstract
- The nitroaromatic explosive 2,4,6-trinitrotoluene (TNT) and the related 2,4-dinitrotoluene (DNT) aretoxic environmental pollutants. The biotransformation and detoxication of these persistent compoundsin higher organisms are of great significance from a health perspective as well as for the biotechnological challenge of bioremediation of contaminated soil. We demonstrate that different human glutathionetransferases (GSTs) and GSTs from the fruit fly Drosophila melanogaster are catalysts of the biotransformationof TNT and DNT. The human GSTs had significant but modest catalytic activities with both DNT and TNT. However, D. melanogaster GSTE6 and GSTE7 displayed outstanding high activities withboth substrates.
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| 8. |
- Nyoto, Imelda Christiana, et al.
(författare)
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A comparison between pulsed electric field and moderate electric field for their effectiveness in improving the freezing tolerance of rocket leaves
- 2023
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Ingår i: Biochemistry and Biophysics Reports. - 2405-5808. ; 35
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Tidskriftsartikel (refereegranskat)abstract
- Two electrotechnologies: pulsed electric fields (PEF) and moderate electric field (MEF) in combination with vacuum impregnation of glycerol as cryoprotectant were used to increase the freezing tolerance of rocket leaves. Rocket leaves were treated with PEF using a nominal field strength of 1200 V/cm or MEF at different combinations of voltage and frequency. Leaves were then immersed in a glycerol solution at 32, 36 and 40% (w/v) under vacuum for 26 min. After this treatment, the leaves were allowed to rest for 3 days before they were frozen and thawed. Leaf survival was assessed at different time points after thawing with microscopic observations and wilting tests. When the viability of the leaves was assessed 5 min after thawing, 60–68% of the leaves in the batch survived. There was no difference in the levels of surviving leaves when PEF and the lowest-tested voltage used in MEF were tested. However, from the leaves surviving 5 min after thawing, approximately half of them die over a 24 h period after thawing.
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| 9. |
- Olsson, Frida, et al.
(författare)
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Effects of 1a,25-dihydroxyvitamin D-3 and tacalcitol on cell signaling and anchorage-independent growth in T98G and U251 glioblastoma cells
- 2022
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier. - 2405-5808. ; 31
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Tidskriftsartikel (refereegranskat)abstract
- The active hormonal form of vitamin D, 1 alpha,25-dihydroxyvitamin D-3, is reported to have 1000s of biological targets. The growth-suppressive properties of 1 alpha,25-dihydroxyvitamin D-3 and its synthetic analogs have attracted interest for the development of treatment and/or prevention of cancer. We examined effects of 1 alpha,25-dihydroxyvitamin D-3 and the vitamin D analog tacalcitol on signaling pathways and anchorage-independent growth in T98G and U251 glioblastoma cells. Assay of signaling proteins important for cellular growth indi-cated suppression of p70-S6 kinase levels by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G cells, whereas the levels of PLC gamma, a target for phospholipid signaling, was slightly increased. Activation of STAT3, an important regulator of malignancy, was suppressed by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol in T98G and U251 cells. However, despite the close structural similarity of these compounds, suppression was stronger by tacalcitol (1 alpha,24-dihydroxyvitamin D-3), indicating that even minor modifications of a vitamin D analog can impact its effects on signaling. Experiments using soft agar colony formation assay in T98G and U251 cells revealed significant suppression by 1 alpha,25-dihydroxyvitamin D-3 and tacalcitol on anchorage-independent growth, a property for cancer invasion and metastasis known to correlate with tumor-igenicity. These findings indicate that vitamin D and its analogs may be able to counteract the oncogenic transformation, invasion and metastatic potential of glioblastoma and prompt further study of these compounds in the development of improved therapy for brain cancer.
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| 10. |
- Phan-Xuan, Tuan, et al.
(författare)
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The role of water in the reversibility of thermal denaturation of lysozyme in solid and liquid states
- 2021
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Ingår i: Biochemistry and Biophysics Reports. - : Elsevier B.V.. - 2405-5808. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- Although unfolding of protein in the liquid state is relatively well studied, its mechanisms in the solid state, are much less understood. We evaluated the reversibility of thermal unfolding of lysozyme with respect to the water content using a combination of thermodynamic and structural techniques such as differential scanning calorimetry, synchrotron small and wide-angle X-ray scattering (SWAXS) and Raman spectroscopy. Analysis of the endothermic thermal transition obtained by DSC scans showed three distinct unfolding behaviors at different water contents. Using SWAXS and Raman spectroscopy, we investigated reversibility of the unfolding for each hydration regime for various structural levels including overall molecular shape, secondary structure, hydrophobic and hydrogen bonding interactions. In the substantially dehydrated state below 37 wt% of water the unfolding is an irreversible process and can be described by a kinetic approach; above 60 wt% the process is reversible, and the thermodynamic equilibrium approach is applied. In the intermediate range of water contents between 37 wt% and 60 wt%, the system is phase separated and the thermal denaturation involves two processes: melting of protein crystals and unfolding of protein molecules. A phase diagram of thermal unfolding/denaturation in lysozyme - water system was constructed based on the experimental data. © 2021 The Authors
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