Effects of diet, sham-immunization and bleeding on the immune response kinetics for two strains of Cyprinus carpio

The effects of diet and experimental procedures for immunization and bleeding on the immune responsiveness of two strains of Cyprinus carpio were investigated. In addition, the relationship between the genetic structure of these fish, based upon the pattern of scaling, and antibody production was studied. The antibody response to sheep red blood cells (SRBC) was assessed by direct haemagglutination. The control titres for both uninjected and sham-immunized fish, using phosphate buffer saline, were evaluated for each treatment. The results show that diet and multiple bleeding influence the antibody response kinetics to SRBC. The observed differences are dependent upon the strain from which the serum is isolated. Furthermore, the change in antibody titre in the controls is negligible when compared to the increase observed after immunization with SRBC.     

Potential allelopatic effects of stilbenoids and flavonoids from leaves of Carex distachya Desf.

The potential allelopathic effects of 14 stilbenoids and five flavonoids, isolated from leaves of Carex distachya Desf., were evaluated on the seed germination and seedling growth of three coexisting Mediterranean species (Dactylis hispanica, Petrorhagia velutina, and Phleum subulatum). The structures of the metabolites have been elucidated on the basis of their spectroscopic features (1D and 2D NMR experiments and EI–MS and ESI–MS data). The bioassays showed species-specific effects of the metabolites from C. distachya, specially on the plant growth (root and shoot elongation) which resulted significantly stimulated or inhibited at 10⁻⁴ M concentration. The effects on root elongation is generally greater than the shoot growth at all the tested concentrations (10⁻⁴–10⁻⁸ M). Cluster of biological data showed interesting relationships between the chemical structures of the compounds and their biological effects.     

Lactone diterpenes from the aquatic plant Potamogeton natans

Four lactone diterpenes and two related glucosides with a labdane skeleton have been isolated from the aquatic plant Potamogeton natans. The structures of three new compounds were determined as 19-acetoxy-20-oxo-8(17),13-ent-labdadien-15-->16 lactone, 8(17), 13-ent-labdadien-15-->16,19-->20 dilactone and 6'-acetyl-19-glucopyranosyloxy-8(17),13-ent-labdadien-15-->16 lactone, respectively, by means of spectral analysis. Antialgal assays showed inhibitory activity for some compounds.     

Negative regulation of receptor tyrosine kinase signals

In Metazoans a number of cellular functions are controlled by receptor tyrosine kinases (RTKs) during development and in postnatal life. The execution of these programs requires that signals of adequate strength are delivered for the appropriate time within precise spatial boundaries. Several RTK inhibitors have been identified in invertebrate and mammalian organisms. Because they are involved in tuning and termination of receptor signals, negative regulators of RTK activity fulfill a fundamental function in the control of receptor signaling.     

Stress-induced release of HSC70 from human tumors

In this study, we demonstrate that the pro-inflammatory cytokine interferon-gamma (IFN-gamma) induces the active release of the constitutive form of the 70-kDa heat shock protein (HSC70) from K562 erythroleukemic cells. Treatment of K562 cells with IFN-gamma induced the upregulation of the inducible form of the 70-kDa heat shock protein (HSP70), but not the constitutive form of HSC70 within the cytosol, in a proteasome-dependent manner. In addition, IFN-gamma induced the downregulation of surface-bound HSC70, but did not significantly alter surface-bound HSP70 expression. These findings indicate that HSC70 can be actively released from tumor cells and is indicative of a previously unknown mechanism by which immune modulators stimulate the release of intracellular HSC70. This mechanism may account for the potent chaperokine activity of heat shock proteins recently observed during heat shock protein-based immunotherapy against a variety of cancers.     

Phytotoxicity of secondary metabolites from Aptenia cordifolia

From the fresh leaves or twigs of Aptenia cordifolia, a total of 29 compounds were isolated, including the new tetranoroxyneolignan 18, the new dilignan 19, and the beta-ionone derivative 27, previously only known as a synthetic compound, together with 26 known compounds. The structures of the new products were determined by (1)H-, (13)C-, and 2D-NMR, as well as HR-MS analyses. The phytotoxic effects of the isolates on the germination and growth of the dicotyledon Lactuca sativa L. (lettuce) were studied in the concentration range 10(-4) to 10(-7) M. Several constituents of A. cordifolia were found to be equally active as or superior to 4-hydroxybenzoic acid (HBA) used as positive control.