الفهرس 
Dopamine
Dopamine precursors in plantsOnly 14 pages are availabe for public view
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Abstract
Dopamine is the key to our happiness, and is a type of neurotransmitter that carries nerve impulses through the brain. Adequate dopamine levels in the body help to regulate mood, attention and learning, and can even affect your personality. Faba bean (Vicia faba L.) is the most popular food in the world, especially the Arab world and Egypt. In addition, it has high content of phenylalanine which is the basic precursor for dopamine biosynthesis in human body. Because the brain barrier prevents dopamine to enter from the out but must be synthesized in the brain and then released to the rest of the body . The aim of this study is to find out the most faba bean (Vicia faba L.) genotype which contains high concentrations of phenylalanine as a basic precursor for dopamine biosynthesis in human body. Seeds of four faba bean genotypes (Giza 716, Sakha 1, Sakha 3 and Sakha 4) were planted in open field until fruiting. Faba bean plants were then analyzed using ISSR-PCR and HPLC to find out ISSR markers related to phenylalanine accumulation. Male rabbits were fed on the four faba bean genotypes and their blood was analyzed using HPLC to detect amounts of phenylalanine and tyrosine. Our results indicated that total number of ISSR-PCR bands was 55, out of them (35) bands were polymorphic with 63.6% polymorphism. The highest number of bands (9) was produced by ISSR 07 primer. ISSR 01, ISSR 04 and ISSR 09 primers produced seven bands, while the lowest number of bands was two produced by ISSR 08 primer. ISSR 02 primer showed the highest degree of 82 polymorphism (100%), while ISSR 08 primer showed 0.0% of polymorphism. ISSR 07 primer showed 8 polymorphic bands out of total number of bands (9), with a degree of polymorphism of 88.9%. Total number of marker bands produced was thirteen, four of them were resulted by primer ISSR 07. The primers ISSR 02 and ISSR 05 indicated two marker bands. On the other hand, primers ISSR 03 and ISSR 08 showed no marker bands. Dendrogram cluster analysis indicated that the studied four genotypes were clustered into two main clusters. The two genotypes Giza 716 and Sakha 1 were grouped in one cluster with a high degree of similarity about 98%. Close similarity between these two genotypes suggests that Sakha 1 may be evolved from Giza 716 during breeding programs. While, the two genotypes Sakha 3 and Sakha 4 were grouped in another cluster with a degree of similarity of about 70%. HPLC analysis indicated that Sakha 3 genotype contained higher amounts of phenylalanine in seed coat, seed cotyledons and pod valves, as compared to other three genotypes (Giza 716, Sakha 1 and Sakha 4). Sakha 3 genotype indicated also the highest number of ISSR marker bands (6) which could be correlated to high accumulation of phenylalanine. Blood plasma of rabbits fed on genotypes Giza 716, Sakha 1 and Sakha 4 showed no peaks for phenylalanine amino acid, while the blood plasma of rabbits fed on faba bean genotype Sakha 3 indicated low peaks. Blood plasma of rabbits fed on genotype Giza 716, Sakha 1 and Sakha 4 showed a relatively low tyrosine peak, 83 while the blood plasma of rabbits fed on faba bean genotypes Sakha 3 indicated a relatively higher tyrosine peak. Animal (rabbits) behavior indicated that rabbits fed on Sakha 3 were more calm and relax, while control and rabbits fed on other genotypes showed nervous behavior. Sakha 3 genotype is recommended for human as a good food to maintain high dopamine biosynthesis in human body. Faba bean with high contents of phenolic amino acids is also recommended as fodder plant due to the effects of dopamine in prolactin secretion and induction of growth hormones in animals (Holstein cows), that could be used to increase the livestock in Egypt. characterization of the key enzymes involved in dopamine biosynthesis (phenylalanine hydroxylase and tyrosine hydroxylase) should be considered in future work. Isolation and characterization of the genes coding for these enzymes can help in the production of transgenic faba bean plants containing these genes, and accumulating higher amounts of phenylalanine and tyrosine amino acids.