Flavescence Dorée-Derived Leaf Yellowing in Grapevine (Vitis vinifera L.) Is Associated to a General Repression of Isoprenoid Biosynthetic Pathways.

Flavescence dorée (FD), caused by the phytoplasma Candidatus Phytoplasma vitis, is a major threat to vineyard survival in different European grape-growing areas. It has been recorded in French vineyards since the mid-1950s, and rapidly spread to other countries. In Portugal, the phytoplasma was first detected in the DOC region of 'Vinhos Verdes' in 2006, and reached the central region of the country in 2009. The infection causes strong accumulation of carbohydrates and phenolics in the mesophyll cells and a simultaneous decrease of chlorophylls, events accompanied by a down regulation of genes and proteins involved in the dark and light-dependent reactions and stabilization of the photosystem II (PSII). In the present study, to better elucidate the basis of the leaf chlorosis in infected grapevine cv. Loureiro, we studied the isoprenoid transcript-metabolite correlation in leaves from healthy and FD-infected vines. Specifically, targeted metabolome revealed that twenty-one compounds (out of thirty-two), including chlorophylls, carotenoids, quinones and tocopherols, were reduced in response to FD-infection. Thereafter, and consistently with the biochemical data, qPCR analysis highlighted a severe FD-mediated repression in key genes involved in isoprenoid biosynthetic pathways. A more diverse set of changes, on the contrary, was observed in the case of ABA metabolism. Principal component analysis (PCA) of all identified metabolites clearly separated healthy from FD-infected vines, therefore confirming that the infection strongly alters the biosynthesis of grapevine isoprenoids; additionally, forty-four genes and metabolites were identified as the components mostly explaining the variance between healthy and infected samples. Finally, transcript-metabolite network correlation analyses were exploited to display the main hubs of the infection process, which highlighted a strong role of VvCHLG, VvVTE and VvZEP genes and the chlorophylls intermediates aminolevulunic acid and porphobilinogen in response to FD infection. Overall, results indicated that the FD infection impairs the synthesis of isoprenoids, through the repression of key genes involved in the biosynthesis of chlorophylls, carotenoids, quinones and tocopherols.

The feasibility of an augment reality system to study the psychophysiological correlates of fear-related responses.

BACKGROUND: Previous studies have successfully used augmented reality (AR) as an aid to exposure-based treatments for anxiety disorders. However, to the best of our knowledge, none of these studies have measured the physiological correlates of the fear response, relying solely on self-reports and behavioral avoidance tests. METHODS: As the physiological defensive reactivity pattern impacts on the treatment effectiveness, we tested the feasibility of an AR system integrated in a mobile and wearable device for assessing the psychophysiological mechanisms (heart rate) involved in fear responses in real-life contexts. Specific phobia was used as a model given its prototypical defensive hyperreactivity toward the feared stimulus (spiders to spider phobics, in the current study). RESULTS: The results showed that the stimuli presented using AR were able to induce physiological alterations in the participants, which were specific depending on the stimulus type (fear or neutral) and on the participants' level of spider fear (phobic and control group). These physiological correlates of the fear response were reflected both in the intensity of heart rate (in relation to the baseline) and in the time needed to react and recover after the stimulus exposure. Finally, we tested a theoretical model that showed that the physiological responses of phobic individuals when facing their phobic stimulus only explained its own data. CONCLUSIONS: We argue in favor of the system's feasibility at capturing and quantifying the physiological dimension of fear-related responses, which may be of great value for diagnostic and treatment purposes in anxiety disorders, namely specific phobia.

Monitoring physiology and behavior using Android in phobias.

In this paper, we present an Android-based system Application - AWARE - for the assessment of the person's physiology and behavior outside of the laboratory. To accomplish this purpose, AWARE delivers context dependent audio-visual stimuli, embedded into the subject's real-world perception, via marker/vision-based augmented reality (AR) technology. In addition, it employs external measuring resources connected via Bluetooth, as well as the smartphone's integrated resources. It synchronously acquires the experiment's video (camera input with AR overlay), physiologic responses (with a dedicated ECG measuring device) and behavior (through movement and location, with accelerometer/gyroscope and GPS, respectively). Psychological assessment is heavily based on laboratory procedures, even though it is known that these settings disturb the subjects' natural reactions and condition. The major idea of this application is to evaluate the participant condition, mimicking his/her real life conditions. Given that phobias are rather context specific, they represent the ideal candidate for assessing the feasibility of a mobile system application. AWARE allowed presenting AR stimuli (e.g., 3D spiders) and quantifying the subjects' reactions non-intrusively (e.g., heart rate variation) - more emphatic in the phobic volunteer when presented with spider vs non phobic stimulus. Although still a proof of concept, AWARE proved to be flexible, and straightforward to setup, with the potential to support ecologically valid monitoring experiments.