Mesolimbic fMRI activations during reward anticipation correlate with reward-related ventral striatal dopamine release

The dopaminergic mechanisms that control reward-motivated behavior are the subject of intense study, but it is yet unclear how, in humans, neural activity in mesolimbic reward-circuitry and its functional neuroimaging correlates are related to dopamine release. To address this question, we obtained functional magnetic resonance imaging (fMRI) measures of reward-related neural activity and [11C] raclopride positron emission tomography (PET) measures of dopamine release in the same human participants, while they performed a delayed monetary incentive task. Across the cohort, a positive correlation emerged between neural activity of the substantia nigra / ventral tegmental area (SN/VTA), the main origin of dopaminergic neurotransmission, during reward anticipation and reward-related [11C] raclopride displacement as an index of dopamine release in the ventral striatum, major target of SN/VTA dopamine neurons. Neural activity in the ventral striatum / nucleus accumbens itself also correlated with ventral striatal dopamine release.Additionally, high reward-related dopamine release was associated with increased activation of limbic structures, such as the amygdala and the hippocampus. The observed correlations of reward-related mesolimbic fMRI activation and dopamine release provide evidence that dopaminergic neurotransmission plays a quantitative role in human mesolimbic reward processing. Moreover, the combined neurochemical and hemodynamic imaging approach used here opens up new perspectives for the investigation of molecular mechanisms underlying human cognition

Kinome Profiling Reveals an Interaction Between Jasmonate, Salicylate and Light Control of Hyponastic Petiole Growth in Arabidopsis thaliana

Plants defend themselves against infection by biotic attackers by producing distinct phytohormones. Especially jasmonic acid (JA) and salicylic acid (SA) are well known defense-inducing hormones. Here, the effects of MeJA and SA on the Arabidopsis thaliana kinome were monitored using PepChip arrays containing kinase substrate peptides to analyze posttranslational interactions in MeJA and SA signaling pathways and to test if kinome profiling can provide leads to predict posttranslational events in plant signaling. MeJA and SA mediate differential phosphorylation of substrates for many kinase families. Also some plant specific substrates were differentially phosphorylated, including peptides derived from Phytochrome A, and Photosystem II D protein. This indicates that MeJA and SA mediate cross-talk between defense signaling and light responses. We tested the predicted effects of MeJA and SA using light-mediated upward leaf movement (differential petiole growth also called hyponastic growth). We found that MeJA, infestation by the JA-inducing insect herbivore Pieris rapae, and SA suppressed low light-induced hyponastic growth. MeJA and SA acted in a synergistic fashion via two (partially) divergent signaling routes. This work demonstrates that kinome profiling using PepChip arrays can be a valuable complementary ∼omics tool to give directions towards predicting behavior of organisms after a given stimulus and can be used to obtain leads for physiological relevant phenomena in planta

Transcriptomic Signatures of Ash (Fraxinus spp.) Phloem

Ash (Fraxinus spp.) is a dominant tree species throughout urban and forested landscapes of North America (NA). The rapid invasion of NA by emerald ash borer (Agrilus planipennis), a wood-boring beetle endemic to Eastern Asia, has resulted in the death of millions of ash trees and threatens billions more. Larvae feed primarily on phloem tissue, which girdles and kills the tree. While NA ash species including black (F. nigra), green (F. pennsylvannica) and white (F. americana) are highly susceptible, the Asian species Manchurian ash (F. mandshurica) is resistant to A. planipennis perhaps due to their co-evolutionary history. Little is known about the molecular genetics of ash. Hence, we undertook a functional genomics approach to identify the repertoire of genes expressed in ash phloem.Using 454 pyrosequencing we obtained 58,673 high quality ash sequences from pooled phloem samples of green, white, black, blue and Manchurian ash. Intriguingly, 45% of the deduced proteins were not significantly similar to any sequences in the GenBank non-redundant database. KEGG analysis of the ash sequences revealed a high occurrence of defense related genes. Expression analysis of early regulators potentially involved in plant defense (i.e. transcription factors, calcium dependent protein kinases and a lipoxygenase 3) revealed higher mRNA levels in resistant ash compared to susceptible ash species. Lastly, we predicted a total of 1,272 single nucleotide polymorphisms and 980 microsatellite loci, among which seven microsatellite loci showed polymorphism between different ash species.The current transcriptomic data provide an invaluable resource for understanding the genetic make-up of ash phloem, the target tissue of A. planipennis. These data along with future functional studies could lead to the identification/characterization of defense genes involved in resistance of ash to A. planipennis, and in future ash breeding programs for marker development

Biodistribution and radiation dosimetry of the A1 adenosine receptor ligand 18F-CPFPX determined from human whole-body PET

(18)F-8-cyclopentyl-3-(3-fluoropropyl)-1-propylxanthine ((18)F-CPFPX) is a potent radioligand to study human cerebral A(1) adenosine receptors and their neuromodulatory and neuroprotective functions with positron emission tomography (PET). The purpose of this study was to determine the biodistribution and the radiation dose of (18)F-CPFPX by whole-body scans in humans.Six normal volunteers were examined with 12 whole-body PET scans from 1.5 min to 4.5 h after injection. Volumes of interest were defined over all visually identifiable organs, i.e. liver, gallbladder, kidneys, small intestines, heart, and brain to obtain the organs' volumes and time-activity curves (TACs). TACs were fitted with exponential functions, extrapolated, multiplied with the physical decay and normalized to injected activities so that the residence times could be computed as area under the curve. Radiation doses were calculated using the OLINDA/EXM software for internal dose assessment in nuclear medicine.The liver uptake shows peak values (decay-corrected) of up to 35% of the injected radioactivity. About 30% is eliminated by bladder voiding. The highest radiation dose is received by the gallbladder (136.2 +/- 66.1 muSv/MBq), followed by the liver (84.4 +/- 10.6 muSv/MBq) and the urinary bladder (78.3 +/- 7.1 muSv/MBq). The effective dose was 17.6 +/- 0.5 muSv/MBq.With 300 MBq of injected (18)F-CPFPX a subject receives an effective dose (ICRP 60) of 5.3 mSv. Thus the effective dose of an (18)F-CPFPX study is comparable to that of other (18)F-labelled neuroreceptor ligands