sodium-bromide and sodium-chlorate

This study concerns the performance evaluation of 6-carboxyl chitin for its wound healing application. 6-Carboxyl chitins were prepared by the oxidation of chitin at C-6 with NaClO/TEMPO/NaBr after α-chitin was pretreated in NaOH/urea solution. The products with different molecular weights were obtained by changing reaction conditions. They all were completely oxidized at C-6 and N-acetylated at C-2 according to FT-IR and NMR results. 6-Carboxyl chitins could stimulate significantly the proliferation of human skin fibroblasts (HSF) and human keratinocytes (HaCaT), and the bioactivities were concentration and Mws dependent. Within the scope of the study, 10-40 kDa of Mws and 10-100 μg/mL of concentrations were most suitable for the HSF proliferation, but the proliferation of HaCaT increased with decreasing the concentration and Mw. In addition, 6-carboxyl chitins could also induce macrophages and fibroblasts to secrete growth factors. Therefore, 6-carboxyl chitins could be expected to be an active ingredient for wound healing.

Topics: Bromides; Cell Proliferation; Chitin; Chlorates; Cyclic N-Oxides; Fibroblasts; Humans; In Vitro Techniques; Keratinocytes; Molecular Weight; Oxygen; Sodium Compounds; THP-1 Cells; Wound Healing

Controlling the morphological characteristics of micellar solutions is important for surfactant performance and for achieving desired properties. In this work we study how monovalent anions of the lyotropic series affect micellization, micellar transitions, and micellar growth of the cationic surfactant N-cetyl pyridinium chloride (CPyCl), with the aim of achieving a tool to methodically tune these self-assembly characteristics. For the first time, a set of ions of the Hofmeister series were studied by combining indirect (surface tension, conductivity, optical absorption, viscosity, dynamic light scattering) and direct-imaging cryogenic-transmission electron microscopy (cryo-TEM). Following recent literature on anionic surfactants, we considered the pyridinium headgroup as a chaotropic cation, interacting with cosmotrope and chaotrope anions (Cl(-), Br(-), NO(3)(-), ClO(3)(-)). We show that the micelles' structure is strongly influenced by both the nature and concentration of added anions and their location in the lyotropic series, but the lyotropic number by itself cannot explain all the effects measured. Especially interesting was the relatively small effect of the chlorate ion on the CMC, but its large effect on micellar transition and growth. We further test the influence of a hydrotrope on the first and second CMC and micellar growth, and compare it with the data obtained with the inorganic salts.

Topics: Anions; Bromides; Cetylpyridinium; Chemical Phenomena; Chlorates; Cryoelectron Microscopy; Micelles; Microscopy, Electron, Transmission; Nitrates; Sodium Chloride; Sodium Compounds; Sodium Salicylate; Surface Tension; Surface-Active Agents

The intact Photosystem I core protein, containing the psaA and psaB polypeptides, and electron transfer components P-700 through FX, was isolated from cyanobacterial and higher plant Photosystem I complexes with chaotropic agents followed by sucrose density ultracentrifugation. The concentrations of NaClO4, NaSCN, NaI, NaBr or urea required for the functional removal of the 8.9 kDa, FA/FB polypeptide was shown to be inversely related to the strength of the chaotrope. The Photosystem I core protein, which was purified to homogeniety, contains 4 mol of acid-labile sulfide and has the following properties: (i) the FX-containing core consists of the 82 and 83 kDa reaction center polypeptides but is totally devoid of the low-molecular-mass polypeptides; (ii) methyl viologen and other bipyridilium dyes have the ability to accept electrons directly from FX; (iii) the difference spectrum of FX from 400 to 900 nm is characteristic of an iron-sulfur cluster; (iv) the midpoint potential of FX, determined optically at room temperature, is 60 mV more positive than in the control; (v) there is indication by ESR spectroscopy of low-temperature heterogeneity within FX; and (vi) the heterogeneity is seen by optical spectroscopy as inefficiency in low-temperature electron flow to FX. The constraints imposed by the amount of non-heme iron and labile sulfide in the Photosystem I core protein, the cysteine content of the psaA and psaB polypeptides, and the stoichiometry of high-molecular-mass polypeptides, cause us to re-examine the possibility that FX is a [4Fe-4S] rather than a [2Fe-2S] cluster ligated by homologous cysteine residues on the psaA and psaB heterodimer.

Topics: Bromides; Centrifugation, Density Gradient; Chlorates; Chlorophyll; Cold Temperature; Cross-Linking Reagents; Cyanobacteria; Digitonin; Electron Spin Resonance Spectroscopy; Electron Transport; Glutaral; Kinetics; Light-Harvesting Protein Complexes; Molecular Weight; Octoxynol; Oxidation-Reduction; Photochemistry; Photosynthetic Reaction Center Complex Proteins; Photosystem I Protein Complex; Plant Proteins; Polyethylene Glycols; Sodium; Sodium Compounds; Sodium Iodide; Spectrophotometry; Thiocyanates; Urea

The time course of the precipitin reactions of concanavalin A with glycogen, dextran and ovalbumin was investigated by a light-scattering method near 30 degrees C in 10 mM-Tris/HCl buffer, pH 7.4, containing neutral salts, i.e. NaCl, KCl, NaBr, KI and NaClO4. With 0.8 microM-lectin and 0.36 mg of glycogen/ml, the half-life, t 1/2, of the precipitin reaction was independent of salt concentration between 0.1 M and 1.5 M, and was the same (175s) in the presence of NaCl, KCl, NaBr and KI but was significantly (27%) higher in NaClO4. In contrast, the five salts caused significant to marked enhancement in t 1/2 for the reactions of concanavalin A with dextran and ovalbumin. Likewise, whereas the turbidity produced in 1 h as a result of lectin-glycogen precipitation remained unchanged, those measured for the binding of dextran and ovalbumin were decreased in the presence of three salts. The increase in t 1/2 and decrease in turbidity were found to be higher with NaClO4, followed by KI; NaBr produced moderate and NaCl (or KCl) small but generally significant inhibition of the precipitin reactions with dextran and ovalbumin. The results showed that the lectin-ligand precipitin reactions involve salt-sensitive polar interactions that are less pronounced with compactly folded ligands such as glycogen.

Topics: Bromides; Chlorates; Concanavalin A; Dextrans; Glycogen; Ligands; Ovalbumin; Potassium Chloride; Potassium Iodide; Precipitin Tests; Salts; Sodium; Sodium Chloride; Sodium Compounds; Time Factors