Fabrication of Magnesium-Silicon Nanocomplexes by the Interaction of Polyphenylsiloxane with Magnesium Carbonate

The interaction of magnesium carbonate with polyphenylsiloxane under the conditions of mechanochemical activation with subsequent heating has been investigated. Based on the TGA and DTA data, it has been shown that, upon heating up to 420°C, the reaction proceeded completely with the release of carbon dioxide. The polymer was dissolved in DMFA and purified by repeated precipitation with water. The polymer yield was 64%. The residue insoluble in organic solvents has been obtained by evaporation of an aqueous solution. The composition and structure of the synthesis products have been analyzed by means of element analysis, IR spectroscopy, and diffractometry. It has been demonstrated that the fraction soluble in DMFA had a silicon-to-magnesium ratio equal to 4.2, while the fraction isolated from water had this ratio equal to 1.0. The IR and XRD data enabled one to conclude that, regardless of the different compositions, the structures of all fractions were similar and corresponded to mesomorphic layered polymers produced by the ion exchange method.

Structural Characteristics of Pheomelanin-Like Pigment from Lachnum singerianum

Melanin was isolated from the mycelium of Lachnum singerianum YM-292 (LSM) by alkaline extraction, acid hydrolysis, and repeated precipitation with a yield of 8.85 g/100 g (dry weight basis). Scanning electron microscopy showed that LSM had a blocky crystal structure with an irregular surface. The percentages of C, H, N, O and S in LSM measured by the elemental analyzer were 54.44%, 6.65%, 8.25%, 24.24% and 6.42%, respectively. Infrared spectroscopy indicated that LSM had a typical indole structure, and1H-NMR spectroscopy revealed signal peaks in the aliphatic and aromatic regions. It was concluded that LSM had a structural model of pheomelanin-like pigment.

The antigenicity of myosin and C-protein

Rabbit myosin prepared in the conventional manner by repeated precipitation at low ionic strength was recently shown to contain substantial amounts of impurities; the principal impurity is a component of the myofibril called C-protein. Because antiserum to such conventionally prepared myosin has been used in the past for labelling studies of muscle, it was necessary to study the immunological characteristics of myosin and C-protein and in particular to test the specificity of this antiserum. Antisera to both rabbit myosin and C-protein have been successfully elicited in goats. These antisera have been analysed by immunodiffusion and by precipitin reactions in solution. The analysis has been helped by the examination of immunoprecipitates by polyacrylamide gel electrophoresis in the presence of sodium dodecylsulphate. It is concluded that: ( a ) C-protein and myosin are antigenically distinct and therefore that C-protein is not derived from myosin. ( b ) Purified myosin can behave as a classically simple antigen giving a single precipitin line when diffused against its homologous antiserum. ( c ) C-protein is a powerful immunogen; the amount present as an impurity in myosin prepared in the conventional way by repeated precipitation at low ionic strength is capable of eliciting a large amount of antibody. Consequently the pattern obtained by labelling myofibrils with antiserum to conventionally prepared myosin would contain information about the location of C-protein superimposed on information about the location of myosin.

Comparison of extracellular polysaccharide of Xanthomonas campestris from culture and from infected cabbage leaves

The extracellular polysaccharide fraction of Xanthomonas campestris was precipitated with hexadecyltrimethylammonium bromide from aqueous extracts of cabbage leaves infected with the black rot pathogen, and further purified by repeated precipitation with ethanol. The polysaccharide fraction was shown to be similar to extracellular polysaccharide fraction purified from culture fitlrates of X. campestris. Sugars present in samples of acid-hydrolyzed polysaccharide were identified by gas–liquid chromatography. Chromatograms showed that polysaccharide purified from infected cabbage leaves contained glucose, mannose, and glucuronolactone in ratios similar to those of the polysaccharide from culture filtrates. Polysaccharide purified from noninfected cabbage leaves contained only glucose and galactose. The polysaccharide from infected cabbage leaves was serologically related to polysaccharide from culture filtrates. In immunodiffusion tests both the polysaccharide fractions from culture filtrates and that from infected leaves reacted to give two precipitin bands with an antiserum to the polysaccharide from culture filtrates. No precipitin bands formed with polysaccharide from noninfected leaves. Antibodies against the culture polysaccharide were completely removed from the antiserum by the polysaccharides isolated from infected cabbage leaves. A weakly virulent isolate of X. campestris did not produce extracellular polysaccharide in culture filtrates.