Comparison of a retrotransposon-based marker with microsatellite markers for discriminating accessions of Vitis vinifera.

Identification and knowledge concerning genetic diversity are fundamental for efficient management and use of grapevine germplasm. Recently, new types of molecular markers have been developed, such as retrotransposon-based markers. Because of their multilocus pattern, retrotransposon-based markers might be able to differentiate grapevine accessions with just one pair of primers. In order to evaluate the efficiency of this type of marker, we compared retrotransposon marker Tvv1 with seven microsatellite markers frequently used for genotyping of the genus Vitis (VVMD7, VVMD25, VVMD5, VVMD27, VVMD31, VVS2, and VZAG62). The reference population that we used consisted of 26 accessions of Vitis, including seven European varieties of Vitis vinifera, four North American varieties and hybrids of Vitis labrusca, and 15 rootstock hybrids obtained from crosses of several Vitis species. Individually, the Tvv1 and the group of seven SSR markers were capable of distinguishing all accessions except 'White Niagara' compared to 'Red Niagara'. Using the Structure software, the retrotransposon marker Tvv1 generated two clusters: one with V. vinifera plus North American varieties and the other comprising rootstocks. The seven SSR markers generated five clusters: V. vinifera, the North American varieties, and three groups of rootstock hybrids. The percentages of variation explained by the first two components in the principal coordinate analysis were 65.21 (Tvv1) and 50.42 (SSR markers) while the Mantel correlation between the distance matrixes generated by the two types of markers was 42.5%. We conclude that the Tvv1 marker is useful for DNA fingerprinting, but it lacks efficiency for discrimination of structured groups.

Elemental distribution images in prostate samples by X-ray fluorescence microtomography.

An X-ray transmission microtomography (CT) system combined with an X-ray fluorescence microtomography (XRFµCT) system was implemented in the Brazilian Synchrotron Light Laboratory (LNLS), in order to determine the elemental distribution in prostate samples aiming at establishing a correlation between the concentration of some elements and the characteristics and pathology of the tissues. The CT images were reconstructed using a filtered-back projection algorithm and the XRFµCT images were reconstructed using a filtered-back projection algorithm with absorption corrections.

Biological tissues analysis by XRF microtomography.

The main of this work is to determine the elemental distribution in breast and prostate tissue samples in order to verify the concentration of some elements correlated with characteristics and pathology of each tissue observed by the X-ray transmission microtomography (microCT). The experiments were performed at the X-ray fluorescence beamline of the Brazilian Synchrotron Light Laboratory. The microCT images were reconstructed using a filtered-back-projection algorithm and the XRF microtomographies were reconstructed using a filtered-back-projection algorithm with absorption corrections.

Diffraction-enhanced imaging microradiography applied in breast samples.

The diffraction-enhanced imaging (DEI) is a powerful tool to observe tumors and other diseases in breast tissue and provide more precise diagnostics. In this work DEI was used to analyze breast tissues details that have poor attenuation contrast. An X-ray imaging system with DEI techniques was developed using synchrotron radiation. The DEI experiment was performed in D10A-XRD2 beamline at the Brazilian Synchrotron--LNLS. The pre-monochromator, upstream of the beamline was adjusted to 10.7 keV. The samples were positioned between two channel-cut Si(333) in non-dispersive geometry mounted in a double axes diffractometer. A direct conversion water-cooled CCD camera of 1242 pixel x 1152 pixel of 25 microm x 25 microm each was used as a two-dimensional detector in scanning mode. The DEI system could show details in low attenuation tissues based on the contrast imaging obtained by attenuation, refraction gradient and ultra-small angle scatter characteristics. In this work the capacity to observe different types of structures and details in breast tissues were investigated.

Elemental distribution mapping on breast tissue samples.

The main of this work is to determine the elemental and absorption distribution map in breast tissue samples by X-ray fluorescence and X-ray transmission microtomography. The experiments were performed at the X-ray fluorescence beamline (D09B-XRF) in the Brazilian Synchrotron Light Source (LNLS), Campinas, Brazil. A quasi-monochromatic beam produced by a multilayer monochromator was used as an incident beam. The sample was placed on a high precision goniometer and translation stages that allow rotating as well as translating it perpendicularly to the beam. The fluorescence photons were collected with an energy dispersive HPGe detector placed at 90 degrees to the incident beam, while transmitted photons were detected with a fast Na(Tl) scintillation counter () placed behind the sample on the beam direction. All the tomographic images were reconstructed using a filtered-back projection algorithm. In the breast tissue samples, it was possible to determine the distribution of Zn, Cu and Fe in healthy tissue and tumor.

First experiments on diffraction-enhanced imaging at LNLS.

Diffraction-enhanced images have been obtained using two silicon crystals in a non-dispersive set-up at the XRD2 beamline at the Brazilian Synchrotron Light Laboratory (LNLS). A first asymmetrically cut silicon crystal using the (333) reflection vertically expanded the monochromated beam from 1 mm to 20 mm allowing the imaging of the whole sample without movements. A symmetrically cut Si(333) second crystal was used as a Bragg analyzer. Images of biological samples including human tissue were recorded using a direct-conversion CCD detector resulting in enhancement of the contrast compared with absorption-contrast images.