Gangliosides of hepatoma 27, normal and regenerating rat liver.

The highly malignant rat hepatoma 27 was found to have increased amounts of lipid-bound sialic acid as compared with normal liver whereas in regenerating liver the lipid-bound sialic acid level was reduced. In contrast to the liver the hepatoma contained higher amounts of disialogangliosides and no trisialogangliosides, which are abundant in the liver. The main disialoganglioside of the hepatoma had no analogue among the liver gangliosides and was identified as Gal-GalNAc(AcNeu-AcNeu)-Glc-Cer (GD1b), which in other tissues is known to be a precursor of trisialogangliosides. These findings may be explained by a reduced activity of glycosyltransferases in the hepatoma and apparently do not simply reflect differences in growth rate since the ganglioside pattern of regenerating rat liver was not altered significantly in comparison with the liver. Liver and hepatoma microsomes were found to be enriched in gangliosides as compared with whole cells, liver mitochondria were slightly poorer, while the ganglioside level of hepatoma mitochondria was much higher than that of the hepatoma cells. It thus appears that the existing image of the plasma membranes as the only sites of high ganglioside concentration may not hold true for weakly differentiated hepatomas of high malignancy.     

New Plant Growth Stimulants Based on Water-Soluble Nanoparticles of N-Substituted Monoamino-Acid Derivatives of Fullerene C60 and the Study of their Mechanisms of Action

Growth-stimulating effects of water-soluble nanoparticles of N-substituted monoamino-acid derivatives of fullerene C₆₀ (L- and D-alanine, L- and D-valine, L- and D-aspartic acid, β-alanine, and γ-aminobutyric and ε-aminocaproic acids in potassium salt form) were investigated. It was found that the nanoparticle size and relative antiradical activity of fullerene derivatives were factors that influence such physiological parameters of field peas as seed germination rate, germination energy, and root growth capacity. It was shown that the relative antiradical activity of nanoparticles in the selected group of compounds was determined by the total surface area of the nanoparticles regardless of the structure of the amino-acid substituent. The possibility of using amino-acid derivatives of fullerene as effective growth stimulating substances has been demonstrated. A dose-dependent effect of N-(monohydrofullerenyl)-D-alanine potassium salt in a concentration range of 10^–9–10^–11 M on the seed-germination rate and germination energy of field peas has been demonstrated.