When a giant vesicle, composed of neutral and anionic lipid (90:10 mol %), comes into contact with various poly-l-lysines (MW 500-29 300), ropelike structures form within the vesicle interior. By using fluorescence lipids and epi-fluorescence microscopy, we have shown that both neutral and anionic lipids are constituents of the ropes. Evidence that the ropes are also comprised of poly-l-lysine comes from two experiments: (a) direct microinjection of poly(acrylic acid) into rope-containing vesicles causes the ropes to contract into small particles, an observation consistent with a polycation/polyanion interaction; and (b) direct microinjection of fluorescein isothiocyanate (a compound that covalently labels poly-l-lysine with a fluorescent moiety) into rope-containing vesicles leads to fluorescent ropes. The results may be explained by a model in which poly-l-lysine binds to the vesicle exterior, forms a domain, and enters the vesicle through defects or at the domain boundary. The model helps explain the ability of poly-l-lysine to mediate the permeation of a cancer drug, doxorubicine, into the vesicle interior.

According to the general theory of systems, agricultural enterprises are from the category of closed systems in interaction with the external environment and they are close to the category of open systems. The decision maker (DM) needs to have information about the current state of the external environment with statistical analysis of the level achieved and forecasts for the future. Therefore, the task of improving the methods substantiating managerial decisions, using the criterion approach with simulation modeling of agricultural enterprises, is relevant. In the course of building the required model, three subtasks were solved: a conceptual model was built, which was transformed into a machine model, calculations were carried out, and the results were interpreted. Simulation modeling of the agricultural enterprise using a computer should study the performance of the agricultural enterprise before it is designed, at the stage of its setting up and in the course of its operation.

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