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Mccall Mcmahon posted an update 3 days, 3 hours ago
2,4-Dichlorophenol (2,4-DCP), an environmental pollutant, was reported to cause hepatotoxicity. The biochemical mechanisms of 2,4-DCP induced liver injury remain unknown. The present study showed that 2,4-DCP is chemically reactive and spontaneously reacts with GSH and bovine serum albumin to form GSH conjugates and BSA adducts. The observed conjugation/adduction apparently involved the addition of GSH and departure of chloride via the ipso substitution pathway. Two biliary GSH conjugates and one urinary N-acetyl cysteine conjugate were observed in rats given 2,4-DCP. The N-acetyl cysteine conjugate was chemically synthesized and characterized by mass spectrometry and NMR. As expected, 2,4-DCP was found to modify hepatic protein at cysteine residues in vivo by the same chemistry. The observed protein adduction reached its peak at 15 min and revealed dose dependency. HO-3867 research buy The new findings allowed us to better understand the mechanisms of the toxic action of 2,4-DCP.The formation and repair of N2-(trans-isosafrol-3′-yl)-2′-deoxyguanosine (S-3′-N2-dG) DNA adduct derived from the spice and herbal alkenylbenzene constituent safrole were investigated. DNA adduct formation and repair were studied in vitro and using molecular dynamics (MD) simulations. DNA adduct formation was quantified using liquid chromatography-mass spectrometry (LCMS) in wild type and NER (nucleotide excision repair) deficient CHO cells and also in HepaRG cells and primary rat hepatocytes after different periods of repair following exposure to safrole or 1′-hydroxysafrole (1′-OH safrole). The slower repair of the DNA adducts found in NER deficient cells compared to that in CHO wild type cells indicates a role for NER in repair of S-3′-N2-dG DNA adducts. However, DNA repair in liver cell models appeared to be limited, with over 90% of the adducts remaining even after 24 or 48 h recovery. In our further studies, MD simulations indicated that S-3′-N2-dG adduct formation causes only subtle changes in the DNA structure, potentially explaining inefficient activation of NER. Inefficiency of NER mediated repair of S-3′-N2-dG adducts points at persistence and potential bioaccumulation of safrole DNA adducts upon daily dietary exposure.Many cell types in Nature are covered by glycans with a sugar shell on their surface. Synthetic glycopolymer-based materials can mimic these glycans in terms of their variety of biological processes, such as cell growth regulation, adhesion, inflammation by bacteria and viruses, and immune responses. However, the complexity of glycans is still very challenging to be mimicked completely to obtain specific and selective binding ability. Therefore, in this study we aimed to understand how the complexity in the sense of the effect of number of arms and lengths in star-shaped glycopolymers affect the binding activity with different lectins. The Cu-mediated reversible deactivation radical polymerization (Cu-RDRP) technique was employed for the synthesis of mannose containing star-shaped glycopolymers with varying arm number and length. Two sets of star-shaped glycopolymers with on average 1, 3, 7, 8, and 15 arms were successfully synthesized and characterized via 1H NMR, GPC, and DLS. The first set of glycopolymers (SetS1) encompasses 5 star-shaped glycopolymers with a different amount of arms per macromolecule but with equal arm length, whereas in the second set of 5 glycopolymers (Set S2), the amount of sugars per macromolecule was kept constant to obtain glycopolymers with similar glycovalency but in different configuration. Both glycopolymer sets were subsequently evaluated for their lectin-binding affinity toward a series of both newly and previously studied C-type mannose specific lectins present on dendritic and Langerhans cells. Briefly, while Set S1 glycopolymers with the same arm length and different molecular weight showed considerably different biological activities, SetS2 glycopolymers with different arm lengths and the same molecular weight displayed very similar binding abilities, which can indicate that multivalency can be more important than structure complexity to improve the binding behavior of glycopolymers.Antimicrobial peptides (AMPs) are naturally occurring macromolecules made of amino acids that are potent broad-spectrum antibiotics with potential as novel therapeutic agents. This review aims to summarize the fundamental principles concerning the structure and mechanism of action of these AMPs, in order to guide the design of polymeric analogues that organic chemistry can generate. Among those simplified analogues, this review particularly focuses on those made of amino acids called polypeptide polymers they are showing great potential by providing one of the best biomimetic and bioactive structures for further biomaterials science applications.Self-assembled aggregates formed by semidilute polyanion hyaluronan (hyaluronic acid, HA) and an oppositely charged surfactant tetradecyltrimethylammonium bromide (TTAB) in an aqueous phosphate-buffered saline (PBS) solution have been studied via light scattering (LS), small-angle neutron scattering (SANS), and cryogenic transmission electron microscopy (cryo-TEM). The addition of 0-20 mM TTAB to a 27.7 mM (monomer, 1 wt %) HA solution (597 kDa) in PBS buffer leads to soluble complexes until phase separation occurs near charge equilibrium (>20 mM TTAB). While the viscosity remains rather constant, already small amounts of added TTAB lead to the formation of large globular superstructures, which are built in a hierarchical fashion from a locally threadlike structural arrangement of TTA micelles along the stiff HA chains, within the little changed HA network. These globular domains have radii of 60-100 nm and contain 500-700 TTA micelles, which means that they are very “fluffy” and composed of about 99% water. They do not grow in size or number upon further TTAB addition, but, instead, the additional TTA micelles form further threadlike complexes outside of the big globular domains. Such a type of polyelectrolyte-surfactant complexes (PESCs) has not been described before and has to be attributed to the particular properties of HA, which are high stiffness and relatively weak interactions with oppositely charged micelles due to having the charged carboxylic group close to the polysaccharide backbone. These findings demonstrate that the HA network structure in solution basically remains unaffected by complexation with an oppositely charged surfactant, explaining the unchanged rheological behavior and the formation of a unique PESC local “coacervate” structure within the HA hydrogel network.