RESUMEN
The early evolution of plants required the acquisition of a number of key adaptations to overcome physiological difficulties associated with survival on land. One of these was a tough sporopollenin wall that enclosed reproductive propagules and provided protection from desiccation and UV-B radiation. All land plants possess such walled spores (or their derived homologue, pollen). We took a reverse genetics approach, consisting of knock-out and complementation experiments to test the functional conservation of the sporopollenin-associated gene MALE STERILTY 2 (which is essential for pollen wall development in Arabidopsis thaliana) in the bryophyte Physcomitrella patens. Knock-outs of a putative moss homologue of the A. thaliana MS2 gene, which is highly expressed in the moss sporophyte, led to spores with highly defective walls comparable to that observed in the A. thaliana ms2 mutant, and extremely compromised germination. Conversely, the moss MS2 gene could not rescue the A. thaliana ms2 phenotype. The results presented here suggest that a core component of the biochemical and developmental pathway required for angiosperm pollen wall development was recruited early in land plant evolution but the continued increase in pollen wall complexity observed in angiosperms has been accompanied by divergence in MS2 gene function.
Asunto(s)
Evolución Biológica , Biopolímeros/biosíntesis , Vías Biosintéticas , Carotenoides/biosíntesis , Infertilidad Vegetal , Polen/crecimiento & desarrollo , Esporas/crecimiento & desarrollo , Secuencia de Aminoácidos , Arabidopsis/genética , Bryopsida/genética , Bryopsida/crecimiento & desarrollo , Bryopsida/ultraestructura , Regulación de la Expresión Génica de las Plantas , Genes de Plantas , Germinación , Datos de Secuencia Molecular , Mutación/genética , Fenotipo , Filogenia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Polen/genética , Alineación de Secuencia , Homología de Secuencia de Ácido Nucleico , Esporas/ultraestructuraRESUMEN
A case of disseminated infection with Fusarium oxysporum following chemotherapy of acute myelogenous leukemia is reported. Antifungal treatment was successful with a 13-day course of oral terbinafine 250 mg t.i.d. in combination with amphotericin B deoxycholate 1.0-1.5 mg/kg qd and subsequently intravenous liposomal amphotericin B 5 mg/kg qd. Preceding monotherapy with amphotericin B deoxycholate 1.0-1.5 mg/kg qd had not stopped the progression of infection. The combination therapy described here represents a novel approach to the treatment of Fusarium spp. in the immunocompromised host in whom Fusarium spp. are known to cause disseminated infection with high mortality.