The role of volatile organic compounds in plant response to environmental stresses

I composti organici volatili biogenici, anche chiamati BVOC, sono metaboliti secondari prodotti e rilasciati nell\u2019ecosistema dagli organismi viventi, incluse le piante. Essi posseggono caratteristiche peculiari, tra le quali il basso peso molecolare, la lipofilia e l\u2019elevata pressione di vapore a temperatura ambiente. Ad oggi, 1700 specie di VOC differenti sono state isolate e caratterizzate. Nelle piante, i VOC rappresentano l\u20191% di tutti i metaboliti secondari conosciuti. Il gruppo pi\uf9 vasto dei VOC comprende i terpenoidi, seguito da fenilpropanoidi e benzenoidi, i derivati di acidi grassi, che includono i cosiddetti \u201cGreen Leaf Volatiles\u201d, e i derivati dalla via di biosintesi degli amminoacidi. I VOC sono emessi non solo dalle foglie, ma anche da fiori e frutti in diverse qualit\ue0 e quantit\ue0. Tuttavia, mentre i VOC emessi dai tessuti riproduttivi hanno lo scopo di aumentare produttivit\ue0 e fitness della pianta, quelli emessi da tessiti vegetativi servono principalmente come strategia di difesa. Il coinvolgimento dei VOC nella protezione delle piante \ue8 stato ampiamente studiato e dimostrato contro vari fattori, tra cui stress sia abiotici (temperatura, siccit\ue0) che biotici (erbivori, agenti patogeni). Difatti, l'interesse per lo sviluppo di strategie agricole sostenibili basate sui VOC \ue8 in aumento. Tuttavia, le conoscenze sui meccanismi molecolari che coinvolgono i VOC in risposta a uno stress specifico presentano diverse lacune. In dettaglio, questa tesi si propone di approfondire (1) il ruolo dell'isoprene, il pi\uf9 abbondante terpene in atmosfera, nella resistenza alla siccit\ue0 (2) i meccanismi difensivi, tra cui l'emissione di VOC e i riarrangiamenti del proteoma, innescati dal fungo Colletotrichum lindemuthianum in Phaseolus vulgaris. Concentrandosi sulla proteomica abbinata all'analisi di VOC e metaboliti, questo lavoro fornisce nuove prove a sostegno dell'importanza dei VOC nella difesa delle piante e fornisce nuovi possibili oggetti per ulteriori studi.Biogenic Volatile Organic Compounds (BVOCs) are secondary metabolites produced by living organisms, especially by plants, and released in the ecosystem. They are characterized by having low molecular weight, lyophilic properties and high vapor pressure at ambient conditions. So far, more than 1700 species of different plant VOCs have been isolated and characterized according to their chemical structure. They represent the 1% of the total secondary metabolites known in plants. The larger group of VOCs are terpenoids (mono-, di-, homo-, hemi- and sesquiterpenes), followed by phenylpropanoids, benzenoids, fatty acid derivates (including Green Leaf Volatiles or GLVs), and derivates from branched-amino acid biosynthesis. VOCs are not only released from leaves, but also from non-green tissues as roots, flowers, and fruits in different quantity and quality. While the VOCs emitted from reproductive organs primarily promote plant productivity, those released by leaves serve mainly for defence. The role of VOCs in plant protection has been widely investigated and proved against various stressors, including abiotic (temperature, drought) and biotic (herbivores, pathogens) sources. In fact, the interest in developing sustainable agricultural strategies based on VOCs is rising. However, the knowledge about molecular mechanisms involving VOCs in response to a specific stress is still missing at some extents. In detail, this thesis aims to deeper investigate (1) the role of the hemiterpene isoprene in drought resistance (2) defensive mechanisms, including VOCs emission and proteome rearrangements, triggered by the fungus Colletotrichum lindemuthianum in Phaseolus vulgaris. By focusing on proteomics coupled with metabolomics and VOCs analysis, this work provides new evidence supporting the importance of VOCs in plant defence and furnish new possible targets for further studies

Privacy through Pseudonymity in Mobile Telephony Systems

Abstract—To protect mobile phone from tracking by third parties, mobile telephony systems rely on periodically changing pseudonyms. We experimentally and formally analyse the mechanism adopted to update these pseudonyms and point out design and implementation weaknesses that defeat its purpose by allowing the identification and/or tracking of mobile telephony users. In particular, the experiments show that the pseudonym changing mechanism as implemented by real networks does not achieve the intended privacy goals. Moreover, we found out that the standard is flawed and that it is possible to exploit the procedure used to assign a new pseudonym, the TMSI reallocation procedure, in order to track users. We propose countermeasures to tackle the exposed vulnerabilities and formally prove that the 3GPP standard should require the establishment of a fresh ciphering key before each execution of the TMSI reallocation procedure to provide unlinkability. I

Formal Verification of Privacy in Pervasive Systems

Pervasive systems enhance a user's everyday experience. However, the use of pervasive sensing and context aware devices can result very intrusive from a privacy perspective. A familiar pervasive device is a mobile phone. Mobile telephony equipment is daily carried everywhere. Avoiding linkability of subscribers by third parties, and protecting their privacy is one of the goals of mobile telecommunication protocols. We use experimental and formal methods to model and analyse the security properties of mobile telephony protocols. We expose novel threats to the user privacy, which make it possible to trace and identify mobile telephony subscribers, and for some of the attacks we demonstrate the feasibility of a low cost implementation. We propose fixes to these privacy issues. We prove that our privacy friendly fixes satisfy the desired unlinkability and anonymity properties. Finally, we develop the first extension of the Pro Verif tool for the automatic verification of equivalence based properties of stateful protocols. This work shows how to formally verity privacy properties of pervasive systems. Moreover, we develop an automatic verification tool for the verification of equivalence based properties of stateful protocols. Further work in this direction will eventually widen the class of security protocols and security properties verifiable using automatic verification tools

Clinical-pathological features of an occult mixed mucinous male breast cancer. a case report

Mucinous carcinoma of the male breast is an uncommon malignant breast neoplasm and its diagnoses remain difficult. It is probably due to such a low rate of breast cancer cases that men tend to be diagnosed at an older age than women and with a later stage of the disease. We describe a case of a 69-year-old male who displayed a palpable lump in his right axilla several years ago, showing signs of cutaneous adnexal mucinous adenocarcinoma after biopsy. After six years and several clinical examination and systemic investigation without results, the patient underwent to fine needle aspiration cytology and subsequently a biopsy of a mass with irregular margins in the retroareolar region of his right breast. The final diagnosis was of a mixed mucinous breast cancer with neuroendocrine differentiation. The tumor cells phenotype showed Synaptophisin (+), CEA (+/-), CK-20 (-), CK-7 (+), TTF-1 (-), estrogen receptor (-), progesterone (-) and HER 2 (++). These results were unusual for a mucinous male breast carcinoma. In the presence of a lesion in the axillary area with no specific primary origin, breast cancer should never be ruled out, even in the absence of clinical evidence and with an immunohistochemical pattern not indicative of mammary origin

Isoprene Emission Influences the Proteomic Profile of Arabidopsis Plants under Well-Watered and Drought-Stress Conditions

Isoprene is a small lipophilic molecule synthesized in plastids and abundantly released into the atmosphere. Isoprene\u2010emitting plants are better protected against abiotic stresses, but the mechanism of action of isoprene is still under debate. In this study, we compared the physiological responses and proteomic profiles of Arabidopsis which express the isoprene synthase (ISPS) gene and emit isoprene with those of non\u2010emitting plants under both drought\u2010stress (DS) and well\u2010watered (WW) conditions. We aimed to investigate whether isoprene\u2010emitting plants displayed a different proteomic profile that is consistent with the metabolic changes already reported. Only ISPS DS plants were able to maintain the same photosynthesis and fresh weight of WW plants. LC\u2013 MS/MS\u2010based proteomic analysis revealed changes in protein abundance that were dependent on the capacity for emitting isoprene in addition to those caused by the DS. The majority of the proteins changed in response to the interaction between DS and isoprene emission. These include proteins that are associated with the activation of secondary metabolisms leading to ABA, trehalose, and proline accumulations. Overall, our proteomic data suggest that isoprene exerts its protective mechanism at different levels: under drought stress, isoprene affects the abundance of chloroplast proteins, confirming a strong direct or indirect antioxidant action and also modulates signaling and hormone pathways, especially those controlling ABA synthesis. Unexpectedly, isoprene also alters membrane trafficking

Geometry of the p-Adic Special Orthogonal Group SO(3)p

We derive explicitly the structural properties of the p-adic special orthogonal groups in dimension three, for all primes p, and, along the way, the two-dimensional case. In particular, starting from the unique definite quadratic form in three dimensions (up to linear equivalence and rescaling), we show that every element of SO(3)p is a rotation around an axis. An important part of the analysis is the classification of all definite forms in two dimensions, yielding a description of the rotation subgroups around any fixed axis, which all turn out to be abelian and parametrised naturally by the projective line. Furthermore, we find that for odd primes p, the entire group SO(3)p admits a representation in terms of Cardano (aka nautical) angles of rotations around the reference axes, in close analogy to the real orthogonal case. However, this works only for certain orderings of the product of rotations around the coordinate axes, depending on the prime; furthermore, there is no general Euler angle decomposition. For p = 2, no Euler or Cardano decomposition exists

Sulfate Aerosols from Non-Explosive Volcanoes: Chemical-Radiative Effects in the Troposphere and Lower Stratosphere

SO2 and H2S are the two most important gas-phase sulfur species emitted by volcanoes, with a global amount from non-explosive emissions of the order 10 Tg-S/yr. These gases are readily oxidized forming SO42− aerosols, which effectively scatter the incoming solar radiation and cool the surface. They also perturb atmospheric chemistry by enhancing the NOx to HNO3 heterogeneous conversion via hydrolysis on the aerosol surface of N2O5 and Br-Cl nitrates. This reduces formation of tropospheric O3 and the OH to HO2 ratio, thus limiting the oxidation of CH4 and increasing its lifetime. In addition to this tropospheric chemistry perturbation, there is also an impact on the NOx heterogeneous chemistry in the lower stratosphere, due to vertical transport of volcanic SO2 up to the tropical tropopause layer. Furthermore, the stratospheric O3 formation and loss, as well as the NOx budget, may be slightly affected by the additional amount of upward diffused solar radiation and consequent increase of photolysis rates. Two multi-decadal time-slice runs of a climate-chemistry-aerosol model have been designed for studying these chemical-radiative effects. A tropopause mean global net radiative flux change (RF) of −0.23 W·m−2 is calculated (including direct and indirect aerosol effects) with a 14% increase of the global mean sulfate aerosol optical depth. A 5–15 ppt NOx decrease is found in the mid-troposphere subtropics and mid-latitudes and also from pole to pole in the lower stratosphere. The tropospheric NOx perturbation triggers a column O3 decrease of 0.5–1.5 DU and a 1.1% increase of the CH4 lifetime. The surface cooling induced by solar radiation scattering by the volcanic aerosols induces a tropospheric stabilization with reduced updraft velocities that produce ice supersaturation conditions in the upper troposphere. A global mean 0.9% decrease of the cirrus ice optical depth is calculated with an indirect RF of −0.08 W·m−2

Risk of diagnostic delay in congenital thrombotic thrombocytopenic purpura

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Impact of Stratospheric Volcanic Aerosols on Age-of-Air and Transport of Long-Lived Species

The radiative perturbation associated to stratospheric aerosols from major explosive volcanic eruptions may induce significant changes in stratospheric dynamics. The aerosol heating rates warm up the lower stratosphere and cause a westerly wind anomaly, with additional tropical upwelling. Large scale transport of stratospheric trace species may be perturbed as a consequence of this intensified Brewer–Dobson circulation. The radiatively forced changes of the stratospheric circulation during the first two years after the eruption of Mt. Pinatubo (June 1991) may help explain the observed trend decline of long-lived greenhouse gases at surface stations (approximately −8 and −0.4 ppbv/year for CH4 and N2O, respectively). This decline is partly driven by the increased mid- to high-latitude downward flux at the tropopause and also by an increased isolation of the tropical pipe in the vertical layer near the tropopause, with reduced horizontal eddy mixing. Results from a climate-chemistry coupled model are shown for both long-lived trace species and the stratospheric age-of-air. The latter results to be younger by approximately 0.5 year at 30 hPa for 3–4 years after the June 1991 Pinatubo eruption, as a result of the volcanic aerosols radiative perturbation and is consistent with independent estimates based on long time series of in situ profile measurements of SF6 and CO2. Younger age of air is also calculated after Agung, El Chichon and Ruiz eruptions, as well as negative anomalies of the N2O growth rate at the extratropical tropopause layer. This type of analysis is made comparing the results of two ensembles of model simulations (1960–2005), one including stratospheric volcanic aerosols and their radiative interactions and a reference case where the volcanic aerosols do not interact with solar and planetary radiation