The responses of the inner retinal neurons of turtle to light spots of sizes were studied in an attempt to reveal characteristics that may reflect possible interactions of the neural circuits underlying the center and surround responses. For the ON-OFF cells, the responses were also analyzed to observe whether interference or augmentation of these responses occur. The intracellular recordings revealed several such interactions, observed either in the form of altered spike activity or as changes in the transiency of the light responses. The ON-responding amacrine cell presented in this study became more sustained, while for the ON-OFF amacrine cells larger light spots tended to make the responses more transient and both the ON and OFF components became more pronounced. The spiking activity of the OFF-type ganglion cell shifted in relation to the light stimulus and the number of spikes observed upon presentation of larger spots increased. We suggest that the surround circuits activated by increasing light spots may substantially influence and reorganize not only the overall center-surround balance, but also the center response of the cells. Although it cannot be excluded that intrinsic membrane properties also influence these processes to some extent, it is more likely that lateral inhibition and disinhibitory mechanisms play the leading role in this process.
Two novel technologies were applied in order to investigate concentration and formulation of anthocyanins for potential use in food industry. Integrated membrane process technology was applied for concentrating elderberry juice. In the first step, the juice was clarified by microfiltration, followed by a pre-concentration step with reverse osmosis. Finally, the juice was concentrated to the end concentration of 56 °Brix by osmotic distillation. The elderberry juice concentrate was formulated in a powderous form by a high-pressure process — Particles from Gas Saturated Solution (PGSS™) — using supercritical CO2. The applied carrier material was palm fat. The products with different anthocyanin-carrier ratios were measured for their colour properties (lightness, hue angle, and saturation). Colour stability was monitored for prolonged storage at different conditions (light/dark and ambient temperature/ refrigerator). The obtained powderous anthocyanin-palm fat products showed good colour stability, which gives good bases for potential applications in the future.