Search

Multifunctional proteins are interesting candidates for nonviral gene transfer to and expression in their target cells. Since at difference of viral vectors, the performance of these vehicles depends on their functional optimisation, a better comprehension of the molecular organisation within protein–DNA complexes would be of great help in reaching their full delivery potential. In this work, we have characterised an RGD-tagged, cell-targeted multifunctional β-galactosidase carrying a poly-lysine-based DNA-binding domain. In solution, the engineered enzyme spontaneously forms proteinaceous particles of between 20 and 40 nm in diameter that might contain around 10 molecules of enzymatically active protein. Plasmid DNA is efficiently condensed into these particles without modification of the shape, morphology or enzymatic activity, indicative of a comfortable molecular accommodation to the DNA-binding domains. Although the RGD peptide remains equally solvent-exposed and immunoreactive at different DNA–protein ratios, an optimal expression level of cell-delivered genes and integrin-binding specificity are both achieved at 0.02 μg of DNA per μg of protein, indicative of influences of the packaged nucleic acid on the interaction between filled vehicles and the receptors of target cells.

The aim of this study was to determine the effects of leptin treatment on prepro-orexin and orexin receptor expression in the rat hypothalamus. Adult male rats, food-deprived for 48 and 72 h, were treated one time with vehicle or leptin (10 μg, icv). Prepro-orexin mRNA content was measured by semiquantitative RT-PCR, Northern blot, and in situ hybridization; orexin receptor 1 and 2 mRNA content was quantified by Northern blot and/or semiquantitative RT-PCR. Our results indicate that leptin inhibits a fasting-induced increase in prepro-orexin mRNA and orexin receptor 1 mRNA levels in the rat hypothalamus, while orexin receptor 2 mRNA levels were unchanged in all situations evaluated. These data provide direct evidence for an additional mechanism of adaptation of the hypothalamus to food deprivation and for a new effect of leptin in the regulation of food intake.

ABSTRACTMicropropagation of Astragalus maximus Willd. through axillary bud culture was achieved 30 day-old plants. The shoots of plants were used as explants for micropropagation. The explants were cultured on MS media supplemented with BA (0.2, 0.5, 1.0 mg/l), ZR (0.2, 0.5, 1.0 mg/l) and their combinations with 0.4 mg/l NAA. After 20 days, micropropagation was strongly induced in MS medium supplemented with 0.5 mg/l ZR, ∼30 shoots obtained from each explant. In all other treatments, proliferation number on per explant varied to 2–3. Propagated shoots were cultured on MS medium without plant growth regulators, MS medium supplemented with 0.2–1.5 mg/l NAA and ½ MS with 1.5 % sucrose. Root induction was only achieved on ½ MS containing 1.5 % sucrose after 20 days. Plane MS and MS medium with 0.2, 0.4, 0.8, 1.2 and 1.5 mg/l NAA did not induce root formation.