Anna Maria Marras

Phospholipase Dζ2 Drives Vesicular Secretion of Auxin for Its Polar Cell-Cell Transport in the Transition Zone of the Root Apex

Auxin (IAA) is versatile signaling molecule of plants, currently classified as plant hormone. But there are data suggesting that auxin is acting also as plant-specific morphogen, electric-responses inducing transmitter, and as general signaling molecule used for plant-bacteria communication. Our previous data revealed that auxin is associated with secretory endosomes and also highly enriched within cell walls of cells active in transcellular auxin transport. Our present data, based on in vivo non-invasive auxin flux recordings, reveal that auxin is secreted out of synaptic-like domains specialized for efflux of auxin in root apex cells highly active in polar cell-cell transport of auxin. We obtained both genetic and pharmacological evidence that phospholipase Dζ2 drives vesicular secretion of auxin for its polar transcellular transport in the transition zone of the root apex. Secretion of auxin via secretory vesicles has far-reaching consequences not only for our understanding of cell-cell auxin transport but also for plant sciences as a whole.

A polarographic, oxygen-selective, vibrating-microelectrode system for the spatial and temporal characterisation of transmembrane oxygen fluxes in plants

Abstract. A simple procedure is described for the fabrication of micrometer to nanometer-scale platinum electrodes to be used in a vibrating oxygen-selective system. The electrode was prepared by etching a fine platinum wire and insulating it with an electrophoretic paint. The dimensions allowed this electrode to be used with the “vibrating probe technique” in exploratory studies aimed at mapping and measuring the patterns of net influxes as well as effluxes of oxygen in Olea europaea L. leaves and roots with spatial and temporal resolutions of a few microns and a few seconds, respectively. The magnitude and spatial localisation of O2 influxes in roots was characterised by two distinct peaks. The first, in the division zone, averaged 38 ± 5 nmol m−2 s−1; the second, in the elongation region, averaged 68 ± 6 nmol m−2 s−1. Long-term records of oxygen influx in the elongation region of the root showed an oscillatory regime characterised by a fast oscillation with periods of about 8–9 min. In leaves, the system allowed the measurement of real-time changes in O2 evolution following changes in light. Furthermore, it was possible to obtain “topographical” images of the photosynthetically generated oxygen diffusing through different stomata from a region of the leaf of 120 μm × 120 μm. The combination of topographic and electrochemical information at the micrometer scale makes the system an efficient tool for studying biological phenomena involving oxygen diffusion.

Effect of Hypoxic Acclimation on Anoxia Tolerance in Vitis roots: Response of Metabolic Activity and K+ Fluxes

The effect of a hypoxic pre-treatment (HPT) on improving tolerance to prolonged anoxia conditions in two contrasting Vitis species (V. riparia, anoxia tolerant; V. rupestris, anoxia sensitive) was evaluated. The energy economy of root cells was studied by measuring heat production, the activity of pyruvate decarboxylase (PDC) and alcohol dehdrogenase (ADH), ethanol and ATP production, and K(+) fluxes. The results showed that HPT is an effective tool in order to maintain a sustainable metabolic performance in both the species under anoxia conditions, especially in sensitive species such as V. rupestris. Our results showed that the improved tolerance was mainly driven by: (i) an enhanced activity of key enzymes in alcohol fermentation (ADC and PDC); (ii) the capability to maintain a higher level of respiration, evidenced by a lesser decrease in heat development and ATP production; and (iii) the maintenance of a better ion homeostasis (highlighted by measurement of K(+) fluxes) and K(+) channel functionality.

Transcranial Magnetic Stimulation in AlzheimerâÂÂs Disease: A Review ofInvestigational and Therapeutic Findings

Alzheimer’s disease pathophysiology still remains unclear and current pharmacological strategies have limited effectiveness, so that the search for alternative and/or complementary therapeutic strategies is a compelling need, as well as a detailed characterization of the disease progression and its neurophysiological correlates. Transcranial Magnetic Stimulation (TMS),has been employed by a number of studies to physiologically characterize AD, investigating cortical reactivity, plasticity and functional connectivity. A few studies also investigated the therapeutic role of repetitive TMS to enhance cognitive functions in AD. Herein we review a total of thirty-two studies evaluating both investigational and therapeutic role of TMS. Although promising, therapeutic results are still very preliminary and need to be taken with caution, while insights have been provided by most investigational studies.

Better than treated as usual: Transcranial magnetic stimulation augmentation in selective serotonin reuptake inhibitor-refractory obsessive-compulsive disorder, mini-review and pilot open-label trial.

Objective: 1 Hz repetitive transcranial magnetic stimulation (rTMS) over the supplementary motor area has been shown to be effective in a subset of obsessive–compulsive disorder (OCD) subjects, yet these results are still to be confirmed. This preliminary study compares the efficacy of augmentation with 1 Hz rTMS over the supplementary motor area and the usual augmentation treatment (TAU; treated as usual) with antipsychotics in a sample of selective serotonin reuptake inhibitor (SSRI)-refractory OCD patients. Method: Fifty SSRI-refractory OCD patients consecutively admitted were studied: 25 were treated with a three-week trial of 1Hz, bilateral rTMS over the supplementary motor area and 25 with antipsychotic drugs. Yale–Brown Obsessive–Compulsive Scale (Y-BOCS; primary outcome measure), Hamilton Depression and Hamilton Anxiety scales were administered at first, second and third week of treatment. Results: Y-BOCS showed a statistically significant time effect from the baseline to the third week, with a 68% of responders (Y-BOCS score reduction of ⩾ 25%), in comparison with 24.0% in the TAU group. In the rTMS group, 17.6% of patients achieved remission. Conclusions: 1 Hz rTMS over the supplementary motor area appeared to be effective in approximately 2/3 of SSRI-refractory OCD subjects, whereas in the TAU group only 1/4 of subjects were responders. The supplementary motor area might be a new target area to be further explored with neuromodulation for OCD treatment.

Transcranial Magnetic Stimulation for the Treatment of Pharmacoresistant Nondelusional Auditory Verbal Hallucinations in Dementia

Auditory verbal hallucinations (AVHs) are known as a core symptom of schizophrenia, but also occur in a number of other conditions, not least in neurodegenerative disorders such as dementia. In the last decades, Transcranial Magnetic Stimulation (TMS) emerged as a valuable therapeutic approach towards several neurological and psychiatric diseases, including AVHs. Herein we report a case of a seventy-six-years-old woman with vascular-degenerative brain disease, complaining of threatening AVHs. The patient was treated with a high-frequency temporoparietal (T3P3) rTMS protocol for fifteen days. A considerable reduction of AVHs in frequency and content (no more threatening) was observed. Although further research is needed, this seems an encouraging result.

Obsessive compulsive and related disorders: comparing DSM-5 and ICD-11.

Obsessive-compulsive disorder (OCD) has been recognized as mainly characterized by compulsivity rather than anxiety and, therefore, was removed from the anxiety disorders chapter and given its own in both the American Psychiatric Association (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and the Beta Draft Version of the 11th revision of the World Health Organization (WHO) International Classification of Diseases (ICD-11). This revised clustering is based on increasing evidence of common affected neurocircuits between disorders, differently from previous classification systems based on interrater agreement. In this article, we focus on the classification of obsessive-compulsive and related disorders (OCRDs), examining the differences in approach adopted by these 2 nosological systems, with particular attention to the proposed changes in the forthcoming ICD-11. At this stage, notable differences in the ICD classification are emerging from the previous revision, apparently converging toward a reformulation of OCRDs that is closer to the DSM-5.

New Solid State Microsensors in Plant Physiology

Solid state microelectrodes are being increasingly used in many areas of plant physiology, ranging from classical electrophysiology studies to new applications such as scanning tunneling microscopy or atomic force microscopy. When the size of the sensors is decreased from the millimeter to the micrometer scale, many changes occur in their behavior and use. These changes lead to dramatic improvements in the quality of physiological data and make achievable experiments previously impossible. The major areas of improvement include increased temporal resolution, increased sensitivity and the ability to make spatial resolved measurements. Electrochemical methods have significant advantages over the other techniques to monitor local concentrations of a chemical compound near plant tissues. In fact, microelectrodes (amperometric or voltammetric) can be positioned close to the cells and provide a means to estimate the local concentration. Electrochemical sensors for use in plants should display high selectivity and sensitivity, long-term calibration stability, and possess a small size. In addition, if assessing concentrations at different distances from a tissue, as in the case of the self-referencing technique (see chapters by Smith et al.; Fejio; Shabala in this book for exhaustive details on the self-referencing technique), it is essential that the tips of the microelectrodes have a planar geometry so that precise concentrations at precise distances away from the source/sink, can be determined with good spatial resolution. Another factor of crucial importance in the use of the microelectrode as a vibrating probe is a fast response time. Indeed, the sensor remains in the two measurement positions for times not longer than few seconds (usually, less than 5 s, often 2–3 s). Ideally, the electrode response time should permits measurements to be made on a subsecond time scale. In the following pages, four different new solid state microsensors to be used in plants research will be discussed: 7 New Solid State Microsensors in Plant Physiology

Transcranial Magnetic Stimulation Treatment for Motor Symptoms inParkinsons Disease: A Review of Two Decades of Studies

In the last two decades, repetitive Transcranial Magnetic Stimulation (rTMS) has been increasingly employed in Parkinson’s disease (PD) to enhance and restore motor function. Different cortical regions have been investigated as treatment targets (i.e. primary motor cortex, dorsolateral prefrontal cortex and supplementary motor area) and stimulation parameters (frequency, intensity, number of pulses) showed high heterogeneity between studies. Herein we review 40 studies, both open-label and randomized controlled trials: mixed results have been yielded regarding the effectiveness of rTMS treatment for motor symptoms in PD, due to the high variability of employed protocols, sham procedures and target regions. Although overall results seem to support the notion of potential beneficial effects of rTMS in PD, further research is needed to identify the optimal treatment parameters and to evaluate the potential conjunct use of rTMS in patients with deep brain stimulation (DBS) implants.