Potentiometric and spectroscopic data have shown that α-hydroxymethyl-L-serine residue may play an important role in the coordination of tripeptides to Cu
2+ ions. The alcoholic groups in the amino ...acid side chain are very effective in the stabilization of the complexes formed. It is also likely that at basic solutions, the alcoholic group may dissociate proton and bind to metal ion directly via the O
− oxygen. The increase in stability is up to 3.7 orders of magnitude when compared to simple tri-Ala containing systems.
The homooligopeptide series based on O,O-isopropylidene-α-hydroxymethylserine from dimer through pentamer has been synthesized to examine the conformational preferences of this new ...Cα-tetrasubstituted α-amino acid characterized by concomitant C i α ↔ C i α cyclization and presence of two ether oxygen atoms in the γ-positions of the six-membered ring 1,3-dioxane system. To this aim we have exploited X-ray diffraction in the crystal state and FTIR absorption and 1H NMR techniques in solution. The results obtained are compared with those of the homooligopeptides based on the related cyclohexane-containing Cα-tetrasubstituted residue. We conclude that in the former peptides a competition takes place between the classical intramolecular (peptide) CO···H−N (peptide) H-bonds, stabilizing the β-bend/310-helical structures, and the newly discovered (peptide) N i +1−H···O i γ (side-chain ether) intramolecular H-bonds. The extent of regular (incipient) 310-helix formation, where this latter type of H-bond is absent, tends to increase as peptide main-chain length increases. As a result of this intramolecular N−H···Oγ interaction, the critical main-chain length for 310-helix formation in the crystal state shifts from the shortest possible oligomer, the terminally protected trimer, in the cyclohexane series to the pentamer in the 1,3-dioxane series. Interestingly, a strict correlation has been found between the observed (peptide) N i +1−H···O i γ (side-chain ether) intramolecular H-bond and (i) the backbone ψ torsion angle of the i residue (extended), and (ii) the disposition of the α-amino substituent in the 1,3-dioxane ring of the i + 1 residue (axial).
Elementarz "Historia Mówiona" został przygotowany przez Narodowe Centrum Kultury w ramach programu "Świadkowie Historii". Dziękujemy NCK za udostępnienie publikacji
Acrylamide (ACR) is an amide formed as a byproduct in many heat-processed starchy-rich foods. In utero ACR exposure has been associated with restricted fetal growth, but its effects of postnatal ...functional development of small intestine is completely unknown. The current study investigated the time- and segment-dependent effects of prenatal ACR exposure on morphological and functional development of small intestine in weaned rat offspring. Four groups of pregnant female Wistar rats were exposed to ACR (3 mg/kg b.w./day) for 0, 5, 10 and 15 days during pregnancy. Basal intestinal morphology, immunolocalization of gut hormones responsible for food intake and proteins of intestinal barrier, activity of the intestinal brush border disaccharidases, apoptosis and proliferation in intestinal mucosa were analyzed in offspring at weaning (postnatal day 21). The results showed that in utero ACR exposure disturbs offspring gut structural and functional postnatal development in a time- and segment-depended manner and even a short prenatal exposure to ACR resulted in changes in intestinal morphology, immunolocalization of leptin and ghrelin and their receptors, barrier function, activity of gut enzymes and upregulation of apoptosis and proliferation. In conclusion, prenatal ACR exposure disturbed the proper postnatal development of small intestine.
We introduce a new notion of a vector-based robust minimal solution for a vector-valued uncertain optimization problem, which is defined by means of some open cone. We present necessary and ...sufficient conditions for this kind of solution, which are stated in terms of some directional derivatives of vector-valued functions. To prove these results, we apply the methods of set-valued analysis. We also study relations between our definition and three other known optimality concepts. Finally, for the case of scalar optimization, we present two general algorithm models for computing vector-based robust minimal solutions.
Chronic pancreatitis (CP), a progressive inflammatory disease, poses diagnostic challenges due to its initially asymptomatic nature. While CP's impact on exocrine and endocrine functions is ...well-recognized, its potential influence on other body systems, particularly in young individuals, remains underexplored. This study investigates the hypothesis that CP in growing pigs leads to alterations in articular cartilage and subchondral bone, potentially contributing to osteoarthritis (OA) development. Utilizing a pig model of cerulein-induced CP, we examined the structural and compositional changes in subchondral bone, articular cartilage, and synovial fluid. Histological analyses, including Picrosirius Red and Safranin-O staining, were employed alongside immuno-histochemistry and Western blotting techniques. Our findings reveal significant changes in the subchondral bone, including reduced bone volume and alterations in collagen fiber composition. Articular cartilage in CP pigs exhibited decreased proteoglycan content and alterations in key proteins such as MMP-13 and TGF-β1, indicative of early cartilage degradation. These changes suggest a link between CP and musculoskeletal alterations, underscoring the need for further research into CP's systemic effects. Our study provides foundational insights into the relationship between CP and skeletal health, potentially guiding future pediatric healthcare strategies for early CP diagnosis and management.
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