Complexation of DNA with Cationic Surfactant

Transfection of an anionic polynucleotide through a negatively charged membrane is an important problem in genetic engineering. The direct association of cationic surfactant to DNA decreases the effective negative charge of the nucleic acid, allowing the DNA-surfactant complex to approach a negatively charged membrane. The paper develops a theory for solutions composed of polyelectrolyte, salt, and ionic surfactant. The theoretical predictions are compared with the experimental measurements.Comment: 9 pages, 3 figure

Recursion relations for two-loop self-energy diagrams on-shell

A set of recurrence relations for on-shell two-loop self-energy diagrams with one mass is presented, which allows to reduce the diagrams with arbitrary indices (powers of scalar propagators) to a set of the master integrals. The SHELL2 package is used for the calculation of special types of diagrams. A method of calculation of higher order \epsilon-expansion of master integrals is demonstrated.Comment: Talk given by J.Fleischer at 6th International Workshop on Software Engineering, Artificial Intelligence, Neural Nets, Genetic Algorithms, Symbolic Algebra, Automatic Calculation (AIHENP 99), Heraklion, Crete, Greece, 12-16 April, 1999; 8 pages, LaTeX, 3 eps-figure

Advances in the Genetic Engineering of Insect-Resistant Soybeans

This paper reviewed the recent advances in research on, and the modification of the resistance genes, in the construction of vectors, methods of genetic transformation, and the resistance in transgenic plants.Originating text in Chinese.Citation: Zhu, Chengsong, Gu, Heping, Chen, Xin. (1999). Advances in the Genetic Engineering of Insect-Resistant Soybeans. Soybean Science, 18(3), 260-264

Weight optimization of steel trusses by a genetic algorithm - size, shape and topology optimization according to Eurocode

There are benefits of weight optimized structures in many engineering fields. In civil engineering it can for instance be associated with cheaper structural parts and easier transportation. In this study a genetic optimization algorithm for weight minimization of steel trusses has been developed in MATLAB. Constraints regarding material strength and buckling stability are taken from “Eurocode 3: Design of steel structures” and implemented in the algorithm. Genetic programming is an effective search technique based on natural selection. The basic idea is to combine good solutions to a certain problem over many generations to gradually improve the result. All solutions are initially created randomly, and they are individually represented by a binary string with some similarities to natural chromosomes, hence the name genetic programming

Genetic Synthesis of Periodic Protein Materials

Genetic engineering offers a novel approach to the development of advanced polymeric materials, in particular protein-based materials. Biological synthesis provides levels of control of polymer chain architecture that cannot yet be attained by current methods of chemical synthesis. In addition to employing naturally occurring genetic templates artificial genes can be designed to encode completely new materials with customized properties. In the present paper we: 1) review the concepts and technology of creating protein-based materials by genetic engineering, 2) discuss the merits of producing crystalline lamellar proteins by this approach, and 3) review progress made by our group in generating such materials by genetic strategies. Full descriptions appear elsewhere about the parameters to be considered in designing artificial protein genes of this type, the effectiveness of different gene construction and expression strategies utilized by us thus far and, the specific properties of the various materials derived from these efforts (1,2). Progress made by other groups involved in developing periodic proteins by molecular biological strategies are described in refs. 3-8. The latter studies include genetic engineering of artificial silk-like proteins (3,4), poly-aspartylphenylalanine (5), an α/β barrel domain (octarellin; 6), the collagen tripeptide GlyProPro (7) and human tropoelastin (8). Advances with the silk-like proteins (SLP) have been particularly impressive. In addition to producing multi-gram quantities of pure SLP homopolymers, this group has successfully generated block copolymers of SLP interspersed with core peptides of mammalian elastin and the human fibronectin cell attachment element. While publications are still lacking it appears that a numiber of groups are striving to create genetically engineered variants of the repetitive bioadhesive proteins produced by mussels and barnacles (9)

Human serum albumin crystals and method of preparation

Human serum albumin (HSA) crystals are provided in the form of tetragonal plates having the space groups P42(sub 1)2, the crystals being grown to sizes in excess of 0.5 mm in two dimensions and a thickness of 0.1 mm. Growth of the crystals is carried out by a hanging drop method wherein a precipitant solution containing polyethylene glycol (PEG) and a phosphate buffer is mixed with an HSA solution, and a droplet of mixed solution is suspended over a well of precipitant solution. Crystals grow to the desired size in 3 to 7 days. Concentration of reagents, pH and other parameters are controlled within prescribed limits. The resulting crystals exhibit a size and quality such as to allow performance of x ray diffraction studies and enable the conduct of drug binding studies as well as genetic engineering studies