Tunis University

About: Tunis University is a education organization based out in Tunis, Tunisia. It is known for research contribution in the topics: Population & Thin film. The organization has 11745 authors who have published 15400 publications receiving 154900 citations. The organization is also known as: University of Tunis & UT.

Cell-free cloning and biolistic inoculation of an infectious cDNA of potato virus Y

Abstract: Potato virus Y (PVY) full-length cDNA has been found to be refractory to cloning in Escherichia coli cells. A full-length 9.7 kb PVY cDNA was obtained by reverse transcription polymerase chain reaction (RT-PCR) from the RNA of PVY (tuber necrotic strain, PVYNTN). Double-stranded DNA fragments were used as primers (ds megaprimers), to include signals for transcription in vivo (a cauliflower mosaic virus 35S RNA promoter and a nopaline synthase terminator) in the final PCR product. Biolistic bombardment with a helium particle gun was used to inoculate the amplified product to detached tobacco leaves. Inoculation of tobacco plants with ground inoculated leaves followed by northern blot, ELISA and immuno-electron microscopy demonstrated that the DNA was highly infectious with up to 90% of bombarded leaves containing the virus. This methodology will allow the use of reverse genetics in the study of PVY-plant interactions and will also be useful for obtaining infectious cDNA from other viruses with large RNA genomes.

Construction of a real-world bilevel linear programming model of the highway network design problem

Abstract: The formulation of the highway network design problem (NDP) as a bilevel linear program (BLP) allows more realistic solutions taking into account the reaction of users to improvements made by the system. In this paper, a conceptual framework for the optimization of investments in inter-regional highway networks in developing countries is proposed. The model is applied to the Tunisian network using actual data. Considerable effort was expended to make the implementation as realistic as possible, taking into consideration travel times, operating costs, accident costs, improvement costs, conservation laws, and effects of intra-regional flows. A new formulation allowing the incorporation of any improvement cost functions, including non-convex and non-concave functions, is introduced.