Wilhelm Hansberg Torres

Wilhelm Hansberg Torres

Biología Celular y del Desarrollo


103 OTE

Tel. +52 55 56225655

Intereses de Investigación

Cell differentiation as a response to a hyperoxidant state. Antioxidant and pro-oxidant enzymes and their role in cell differentiation. Asexual and sexual spore formation and germination of spores. Cyclic conidiation as a result of a redox cycle. Catalase and catalase-peroxidase structure/function relationships.

Trayectoria profesional

Investigador Titular C, SNI II

Instituto de Fisiología Celular (desde 1991)

Universidad Nacional Autónoma de México

Posdoctorados y estancias

Prof. Glauco Tocchini-Valentini

Estancia Posdoctoral, Roma, Italia

Formación académica

Doctor en Ciencias (Biooquímica)

Facultad de Química, UNAM, México

Maestría en Ciencias (Bioquímica)

Facultad de Química, UNAM, México

Médico Cirujano

Facultad de Medicina, UNAM, México

Líneas de Investigación

Cell differentiation as a response to reactive oxygen species. : Cell differentiation as a response to oxidative stress is our working hypothesis. We utilize Neurospora crassa asexual and sexual life cycles as models of cell differentiation. Asexual spores (conidia) formation in N. crassa can be induced to occur synchronously and the different cell structures can be separated at different times and in quantities that allow a biochemical analysis. Sexual spores are formed by crossing two strains of opposite mating type. Classical genetics and molecular biology techniques are well developed for N. crassa. Its genome has been sequenced and the information is organized and accessible. Many mutant strains are available and some express a cyclic conidiation that can be modulated by light and temperature. We have observed generation of oxidative stress at the start of each morphogenetic transition of the conidiation process. Detection of reactive oxygen species was done with chemiluminescence. Antioxidants inhibit and oxidants promote cell differentiation. We have generated null mutant strains in antioxidant and pro-oxidant enzymes. A catalase null mutant strain tends to develop oxidative stress and forms more aerial hyphae and conidia. Another catalase is accumulated in conidia and is probable important for germination. We have determined the crystal structure of this catalase and found two oxidations at the active site; one is probably caused by singlet oxygen. A mutant strain without catalase-peroxidase increases sexual development. More recently, in collaboration with Dr. J. Aguirre laboratory, we have obtained mutant strains without one of two NADPH oxidases, one inhibits both asexual and sexual development; the other forms ascospores that are unable to germinate.