Prótesis parcial removible

Fotografías, gráficos e ilustraciones: Melchor G. Bocage. -- Diseño de portada y Diagramación: Augusto Giuss

The microbiological transformation of two 15B-hydroxy-ent-kaurene diterpenes by Gibberella fujikuroi

The incubation of 15B-hydroxy-3-oxo-ent-kaur-16-ene (1) with the fungus Gibberella fujikuroi afforded 11B-hydroxy-3,15-dioxo-ent-kaurane (6), 11B,15B-dihydroxy-3-oxo-ent-kaur-16-ene (8), 7B,11B,15B-trihydroxy-3-oxo-ent-kau-16-ene (9), 7a,11B-dihydroxy-3,15-dioxo-ent-kaurane (7), and 7a,11B,15B-trihidroxy-3-oxo-ent-kaur-16-ene (10). The incubation of 15B-hydroxy-ent-kaur-2,16-diene (3) with the same fungus yielded 7a,11B-dihydroxy-15-oxo-ent-kaur-3-ene (12), 7a,11B,15B-trihydroxy-ent-kaur-2,16-diene (13), 7B,-15B-dihydroxy-ent-kaur-2,16-dien-19,6-olide (14), 1B,7B,15B-trihydroxy-ent-kaur-2,16-dien-19-oic acid (15), 7a,11B,16a-trihydroxy-15-oxo-ent-kaur-2-ene (17), and 7a,15B,17-trihydroxy-11B,16B-epoxy-ent-kaur-2-ene (19). These results indicated that a 3-oxo group in ent-kaur-16-ene derivatives inhibits the oxidation at C-19, typical of the biosynthetic pathway of gibberellins and kaurenolides, while a 2,3-double bond or a 15B-OH does not. In both substrates a 15B-alcohol directs hydroxylations at C-11(B) and C-7(a), while in those with a 2,3-double bond the functionalization of C-1(B) is favored.Peer reviewe

Highway to heaven: mammary gland development and differentiation

In recent years, the mammary gland epithelium has been shown to be a mixture of differentiated cell populations in a hierarchical relationship with their stem and progenitor cells. However, the mechanisms that regulate their cellular differentiation processes are still unclear. The identification of genes that govern stem and progenitor cell expansion, or that determine daughter cell fate, will be of crucial interest for understanding breast cancer diversity and, ultimately, improving treatment. Two recent analyses have identified some of the key genes that regulate these processes, lighting up the highway to normal mammary gland development