RFPID: development and 3D-printing of a female physical phantom for whole-body counter.

Whole-body counters (WBC) are used in internal dosimetry forin vivomonitoring in radiation protection. The calibration processes of a WBC set-up include the measurement of a physical phantom filled with a certificate radioactive source that usually is referred to a standard set of individuals determined by the International Commission on Radiological Protection (ICRP). The aim of this study was to develop an anthropomorphic and anthropometric female physical phantom for the calibration of the WBC systems. The reference female computational phantom of the ICRP, now called RFPID (Reference Female Phantom for Internal Dosimetry) was printed using PLA filament and with an empty interior. The goal is to use the RFPID to reduce the uncertainties associated within vivomonitoring system. The images which generated the phantom were manipulated using ImageJ®, Amide®, GIMP®and the 3D Slicer®software. RFPID was split into several parts and printed using a 3D printer in order to print the whole-body phantom. The newly printed physical phantom RFPID was successfully fabricated, and it is suitable to mimic human tissue, anatomically similar to a human body i.e., size, shape, material composition, and density.

Isolation, characterization, and evaluation of three Citrus sinensis-derived constitutive gene promoters.

KEY MESSAGE: Regulatory sequences from the citrus constitutive genes cyclophilin (CsCYP), glyceraldehyde-3-phosphate dehydrogenase C2 (CsGAPC2), and elongation factor 1-alpha (CsEF1) were isolated, fused to the uidA gene, and qualitatively and quantitatively evaluated in transgenic sweet orange plants. The 5' upstream region of a gene (the promoter) is the most important component for the initiation and regulation of gene transcription of both native genes and transgenes in plants. The isolation and characterization of gene regulatory sequences are essential to the development of intragenic or cisgenic genetic manipulation strategies, which imply the use of genetic material from the same species or from closely related species. We describe herein the isolation and evaluation of the promoter sequence from three constitutively expressed citrus genes: cyclophilin (CsCYP), glyceraldehyde-3-phosphate dehydrogenase C2 (CsGAPC2), and elongation factor 1-alpha (CsEF1). The functionality of the promoters was confirmed by a histochemical GUS assay in leaves, stems, and roots of stably transformed citrus plants expressing the promoter-uidA construct. Lower uidA mRNA levels were detected when the transgene was under the control of citrus promoters as compared to the expression under the control of the CaMV35S promoter. The association of the uidA gene with the citrus-derived promoters resulted in mRNA levels of up to 60-41.8% of the value obtained with the construct containing CaMV35S driving the uidA gene. Moreover, a lower inter-individual variability in transgene expression was observed amongst the different transgenic lines, where gene constructs containing citrus-derived promoters were used. In silico analysis of the citrus-derived promoter sequences revealed that their activity may be controlled by several putative cis-regulatory elements. These citrus promoters will expand the availability of regulatory sequences for driving gene expression in citrus gene-modification programs.

New Radiation Dosimetry Estimates for [18F]FLT based on Voxelized Phantoms.

3'-Deoxy-3-[18F]fluorothymidine, or [18F]FLT, is a positron emission tomography (PET) tracer used in clinical studies for noninvasive assessment of proliferation activity in several types of cancer. Although the use of this PET tracer is expanding, to date, few studies concerning its dosimetry have been published. In this work, new [18F]FLT dosimetry estimates are determined for human and mice using Monte Carlo simulations. Modern voxelized male and female phantoms and [18F]FLT biokinetic data, both published by the ICRP, were used for simulations of human cases. For most human organs/tissues the absorbed doses were higher than those reported in ICRP Publication 128. An effective dose of 1.70E-02 mSv/MBq to the whole body was determined, which is 13.5% higher than the ICRP reference value. These new human dosimetry estimates obtained using more realistic human phantoms represent an advance in the knowledge of [18F]FLT dosimetry. In addition, mice biokinetic data were obtained experimentally. These data and a previously developed voxelized mouse phantom were used for simulations of animal cases. Concerning animal dosimetry, absorbed doses for organs/tissues ranged from 4.47 ± 0.75 to 155.74 ± 59.36 mGy/MBq. The obtained set of organ/tissue radiation doses for healthy Swiss mice is a useful tool for application in animal experiment design.

Resistance to Passion fruit woodiness virus in Transgenic Passionflower Expressing the Virus Coat Protein Gene.

We report the use of the coat protein (CP) gene from Passion fruit woodiness virus (PWV) to produce resistant transgenic plants of yellow passion fruit. A full-length CP gene from a severe PWV isolate from the state of São Paulo, Brazil (PWV-SP) was cloned into pCAMBIA 2300 binary vector, which was further introduced into Agrobacterium tumefaciens strain EHA 105. Leaf disks were used as explants for transformation assays, e.g., 2,700 and 2,730 disks excised from plants from the Brazilian cultivars IAC-275 and IAC-277, respectively. In vitro selection was performed in kanamycin. After transferring to the elongation medium, 119 and 109 plantlets of IAC-275 and IAC-277, respectively, were recovered. Integration of the PWV CP gene was confirmed in seven of eight plants evaluated by Southern blot analysis, showing different numbers of insertional events for the CP gene. Three transgenic plants (T3, T4, and T7) expressed the expected transcript, but the 32 kDa PWV CP was detected by Western blot in only two plants (T3 and T4). The results of three successive mechanical inoculations against the transgenic plants using three PWV isolates showed that the primary transformant T2 of IAC-277 was immune to all isolates.

The use of the PMI/mannose selection system to recover transgenic sweet orange plants (Citrus sinensis L. Osbeck).

A new method for obtaining transgenic sweet orange plants was developed in which positive selection (Positech) based on the Escherichia coli phosphomannose-isomerase (PMI) gene as the selectable marker gene and mannose as the selective agent was used. Epicotyl segments from in vitro-germinated plants of Valencia, Hamlin, Natal and Pera sweet oranges were inoculated with Agrobacterium tumefaciens EHA101-pNOV2116 and subsequently selected on medium supplemented with different concentrations of mannose or with a combination of mannose and sucrose as a carbon source. Genetic transformation was confirmed by PCR and Southern blot. The transgene expression was evaluated using a chlorophenol red assay and isoenzymes. The transformation efficiency rate ranged from 3% to 23.8%, depending on cultivar. This system provides an efficient manner for selecting transgenic sweet orange plants without using antibiotics or herbicides.