Articles by Diego Fajardo in JoVE
Rapides à haut débit amylose Détermination dans lyophilisé échantillons de pommes de terre de tubercules Diego Fajardo1, Sastry S. Jayanty2, Shelley H. Jansky1 1USDA-ARS and Department of Horticulture, University of Wisconsin - Madison, 2Department of Horticulture and Landscape Architecture, Colorado State University Ce protocole décrit un procédé colorimétrique haut à travers mettre qui repose sur la formation d'un complexe entre l'iode et les chaînes de molécules de glucose de l'amidon. Iode forme des complexes avec les deux amylose et l'amylopectine dans de longues chaînes. Après l'addition d'iode à un échantillon d'amidon, l'absorption maximale de l'amylose et de l'amylopectine se produit à 620 et 550 nm, respectivement. Le ratio amylose / amylopectine peut être estimé à partir du rapport des valeurs d'absorbance 620 nm et 550 et en les comparant à une courbe standard dans laquelle les concentrations connues spécifiques sont tracées en fonction des valeurs d'absorption. Ce débit élevé, méthode peu coûteuse est fiable et reproductible, permettant l'évaluation des grandes populations de clones de pommes de terre.
Other articles by Diego Fajardo on PubMed
Sequence-indexed Mutations in Maize Using the UniformMu Transposon-tagging Population BMC Genomics. 2007 | Pubmed ID: 17490480 Gene knockouts are a critical resource for functional genomics. In Arabidopsis, comprehensive knockout collections were generated by amplifying and sequencing genomic DNA flanking insertion mutants. These Flanking Sequence Tags (FSTs) map each mutant to a specific locus within the genome. In maize, FSTs have been generated using DNA transposons. Transposable elements can generate unstable insertions that are difficult to analyze for simple knockout phenotypes. Transposons can also generate somatic insertions that fail to segregate in subsequent generations.
Maize Rough Endosperm3 Encodes an RNA Splicing Factor Required for Endosperm Cell Differentiation and Has a Nonautonomous Effect on Embryo Development The Plant Cell. Dec, 2011 | Pubmed ID: 22138152 Endosperm and embryo development are coordinated via epigenetic regulation and signaling between these tissues. In maize (Zea mays), the endosperm-embryo signals are not known, but endosperm cellularization is a key event for embryos to form shoots and roots. We screened seed mutants for nonautonomous functions in endosperm and embryo development with genetically nonconcordant seeds and identified the recessive mutant rough endosperm3 (rgh3). The wild-type Rgh3 allele is required in the endosperm for embryos to develop and has an autonomous role in embryo and seedling development. Endosperm cell differentiation is defective in rgh3. Results from endosperm cell culture indicate that rgh3 mutants remain in a proliferative state through mid-seed development. Rgh3 encodes the maize U2AF(35) Related Protein (URP), an RNA splicing factor involved in both U2 and U12 splicing. The Rgh3 allele produces at least 19 alternative splice variants with only one isoform encoding a full-length ortholog to URP. The full-length RGH3Î± isoform localizes to the nucleolus and displays a speckled pattern within the nucleoplasm, and RGH3Î± colocalizes with U2AF(65). A survey of alternatively spliced transcripts found that, in the rgh3 mutant, a fraction of noncanonical splicing events are altered. Our findings suggest that differentiation of maize endosperm cell types is necessary for embryos to develop. The molecular cloning of Rgh3 suggests that alternative RNA splicing is needed for cell differentiation, development, and plant viability.
Gene Therapy Rescues Photoreceptor Blindness in Dogs and Paves the Way for Treating Human X-linked Retinitis Pigmentosa Proceedings of the National Academy of Sciences of the United States of America. Feb, 2012 | Pubmed ID: 22308428 Hereditary retinal blindness is caused by mutations in genes expressed in photoreceptors or retinal pigment epithelium. Gene therapy in mouse and dog models of a primary retinal pigment epithelium disease has already been translated to human clinical trials with encouraging results. Treatment for common primary photoreceptor blindness, however, has not yet moved from proof of concept to the clinic. We evaluated gene augmentation therapy in two blinding canine photoreceptor diseases that model the common X-linked form of retinitis pigmentosa caused by mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene, which encodes a photoreceptor ciliary protein, and provide evidence that the therapy is effective. After subretinal injections of adeno-associated virus-2/5-vectored human RPGR with human IRBP or GRK1 promoters, in vivo imaging showed preserved photoreceptor nuclei and inner/outer segments that were limited to treated areas. Both rod and cone photoreceptor function were greater in treated (three of four) than in control eyes. Histopathology indicated normal photoreceptor structure and reversal of opsin mislocalization in treated areas expressing human RPGR protein in rods and cones. Postreceptoral remodeling was also corrected: there was reversal of bipolar cell dendrite retraction evident with bipolar cell markers and preservation of outer plexiform layer thickness. Efficacy of gene therapy in these large animal models of X-linked retinitis pigmentosa provides a path for translation to human treatment.