(1916 - 1978)
Médico cirujano. Contribuyó al desarrollo de la cirugía experimental y del trasplante de órganos en Cuba. Se dedicó también a los estudios de Cibernética aplicada a la Medicina y gran parte de su esfuerzo lo consagró a la urgente tarea de reformar los hospitales universitarios y al propio Plan de estudios de la Facultad de Medicina.
Agrarian and Fishery Sciences
2003 | Knowledge contributions of the cultivation environment influence on Bradyrhizobium and Rhizobium in the induction of nodulation in soy and bean.
Main author: María Caridad Nápoles García, del (1).
Coauthors: From (1) Daymy Costales Menéndez, Jorge Corbera Gorotiza, Belkis Morales, Juan C. Cabrera, Ines Reynaldo, Omar Cartaya, Mario Varela; from (2) Germán Hernández; from (3) Eduardo Bordallo y Raúl Hernández; from (4) Josefa Hormanza and from (5) Armando Rodríguez.

The use of leguminous has been increased in human and animal diet for its high protein content and some other qualities. Rizobium, family of bacteria that inhabit the soil, cannot fix nitrogen from the air independently, but in association with leguminous plants. The nitrofixation phenomenon is the consequence of complex molecular plant~microorganism interactions, in which both symbionts determine the final result. Among the numerous factors that influence the success of this interaction, the production of nodulation factors (lipoquitinoligosaccharides) is very important. Nothing has been published on the effect of the cultivation environment on the synthesis of nodulation factors as key molecules in this symbiosis. So far, the environments on which leguminous were inoculated had been only considered for the production of bacterial biomass and not for the possibility to exploit the cell physiologic capacity to produce these biomolecules.

This work includes the researches to determine the inductor effect on the nodulation of different compound and cultivation environments. By means of chemotaxis experiments, nodulation and chromatografic analysis, it was demonstrated the inductor effect of milled soy seed and molasses, as inductors' carriers for several Bradyrhizobium and Rhizobium leguminosarum stumps, which induce solidly the production of Nod factors, essential molecules in symbiosis success. A new cultivation environment was designed with these compounds that allowed increasing cellular multiplication as well as Nod factors' synthesis, and obtaining inoculum of high nodulation capacity in different soy and bean varieties, demonstrating the feasibility of managing the molecular signs which intervene in symbiosis to obtain better results.

The effectiveness of the new environment was proven through studies with Bradyrhizobium elkanii ICA 8001 stump, for which it was genetically transformed introducing in its chromosome, the A Gus marker gene of Escherichia coli that encodes & #946;~glucuronidase enzyme. This allowed detecting the activation of nod genes in front of inductors. The obtained conjugates were evaluated by means of Nod expression tests and confirmed through nodulation in plants.

These results have given rise to: an invention patent; 10 articles in scientific magazines (from these, 2 which are very prestigious) and another accepted in a prestigious magazine; works presented in 22 events, from them 9 international events; several winning works, and the defense of 5 theses.