Humberto Ramírez Medina

Humberto studied Biochemistry at the Technological Institute of Celaya in Mexico. His scientific career began during his Master with study on plant-pathogen interaction, with emphasis on genes from Sclerotium cepivorum involved in its pathogenesis on Allium sativum. He then moved to the Laboratory of excellent geneticist Enrique Cerda-Olmedo at the University of Seville in Spain. During his doctoral courses, he studied the effect of light on transcription of genes for carotenogenesis in Phycomyces blakesleeanus. He analyzed the transcription of genes involved in the carotenogenesis and mating in Blakeslea trispora. For his Diploma, he identified supposed genes for the early processing of beta-carotene in Phycomyces. For his PhD, he continued working under supervision of Prof. Cerda-Olmedo with emphasis on carotenoid cleavage oxygenases of Phycomyces. For this, he moved to the Laboratory of Prof. Salim Al Babili at the University of Freiburg in Germany where he corroborated the enzymatic activity of two oxygenases. These results confirmed the cleaving of beta-carotene and elucidated the first steps in the trisporic acids biosynthesis, essential apocarotenoids for sexual cycle in Mucorales. These results decisively rejected the hypothesis assumed during many years for this pathway. His studies on Phycomyces mutants affected in carotenogenesis and sexual reproduction corroborated that beta-carotene and its cleaving to apocarotenoids are essentials for mating in Mucorales and confirmed that CarS protein (one of the oxygenases mentioned) has a role in the carotenogenesis regulation. He also studied the role of polyamines in growth of Phycomyces. He then moved to the Laboratory of Prof. Alain Tissier at the Leibniz Institute of Plant Biochemistry in Germany. He has engineered transgenic plants of Nicotiana tabacum which produce carotenoids in their glandular trichomes by expression of genes for synthesis of these isoprenoids from Phycomyces and other organisms. He taught Molecular Biology to students of Master and co-supervised a Bachelor Thesis at Technological Institute of Celaya. He supervised training at laboratory of a Genetics course at University of Seville.