DNA-Based Approaches for Traceability and Authentication of Olive Oil

Authentication and traceability of extra virgin olive oil is a challenging research task due to the complexity of fraudulent practices. Various chemical and biochemical techniques have been developed for determining the authenticity of olive oil and in recent years non-conventional methods based on DNA analysis have gained attention, due to high specificity, sensitivity and reliability. DNA analyses have very high discriminating power because ultimately the unique identity of a variety or species is to a great extent genetically dependent. Polymorphisms are genetic variations which refer to the variation in populations or species. Molecular markers provide information on genetic variations and are valuable tools to determine olive oil authenticity. Recently several DNA-based methods have been developed to authenticate olive oil, since analysis of the residual oil DNA with the use of molecular markers can lead to the identification of the variety or the plant species from which it was extracted. The aim of this chapter is to provide an overview of the current trends and critical issues on DNA-targeted approaches used for traceability and authenticity of olive oil. This is considered a rapidly expanding field with significant challenges and prospects which shall be discussed thoroughly

Utjecaj NaCl na fermentaciju zrelih zelenih rajčica cv. Ailsa Braig u rasolu

The effect of osmotic strength on gene expression and activity of the major enzymes of fermentative metabolism of mature green tomato fruit (Solanum lycopersicum cv. Ailsa Craig) has been studied by exposing fruit to brine containing 0 (water), 5 and 10 % NaCl. The fruits were surface sterilized prior to treatment to prevent the growth of microbes naturally present on the skin of the fruit. Changes in fruit expression of fermentation genes and the activity of the respective enzymes as well as physicochemical quality characteristics (soluble solid content, titratable acidity, pH and firmness) were studied in both fruit and brine for 0.5, 1, 1.5, 2, 3, 7 and 14 days. Discrepancies in responses that resulted from the different salt concentrations were obtained at molecular and quality levels. The complex kinetics of solutes between the fruit and the surrounding solution due to osmotic potential has led to different responses of the tissue to fermentation. Tomato fruit showed cracking soon after storage in water; water-stored fruit had higher titratable acidity, lower soluble solid content, and higher induction of anaerobic metabolism as indicated by the expression or the activity of the fermentation enzymes compared to fruit stored in brine with 5 or 10 % NaCl. No cracking was observed in fruit stored in 5 (isotonic) or 10 % NaCl (hypertonic) brine, though in the latter, signs of dehydration were observed. The presence of salt in brine reduced the intensity of fermentative metabolism as indicated by the lower gene expression and enzyme activity. However, fruit stored in brine with 5 % NaCl survived longer than with 0 or 10 % NaCl. The presence of 5 % NaCl in brine caused mild changes of both the fermentative metabolism and the physicochemical characteristics and prevented fruit deterioration during storage.U radu je ispitan utjecaj osmoze na ekspresiju gena i aktivnost glavnih enzima koji sudjeluju u fermentaciji zrelih zelenih rajčica (Solanum lycopersicum cv. Ailsa Craig), i to uranjanjem plodova u vodu i rasol što sadržava 5 ili 10 % NaCl. Površina je plodova prije obrade sterilizirana da bi se spriječio rast mikroorganizama na pokožici ploda. Analizirani su plodovi rajčice i rasol tijekom 0,5; 1; 1,5; 2; 3; 7 i 14 dana skladištenja, te ispitani ovi parametri: promjena ekspresije gena i aktivnost enzima koji sudjeluju u fermentaciji, te fizikalno-kemijska svojstva plodova (udio topljivih tvari, titracijska kiselost, pH-vrijednost i čvrstoća). Utvrđene su razlike u dobivenim rezultatima, i to na molekularnoj razini te u kakvoći plodova. Zaključeno je da utjecaj fermentacije na tkivo ploda rajčice ovisi o složenoj kinetici prelaska otopljenih tvari iz plodova u otopinu zbog razlike osmotskih tlakova. Skladištenje u vodi uzrokovalo je pucanje plodova koji su imali veću titracijsku kiselost i manji udio topljivih tvari. Ekspresija gena i aktivnost enzima pokazali su da je došlo do povećanja anaerobnog metabolizma u tim plodovima, u usporedbi s onima skladištenim u rasolu. Skladištenje plodova u izotoničnoj otopini (5 % soli) nije uzrokovalo njihovo pucanje, a u hipertoničnoj (10 % soli) otopini nije došlo do pucanja već do dehidracije plodova. Dodatkom soli smanjen je intenzitet fermentacije, što je dovelo do manje ekspresije gena i aktivnosti enzima. Trajnost plodova skladištenih u izotoničnoj otopini bila je veća od onih skladištenih u vodi ili hipertoničnoj otopini. Manja koncentracija soli u otopini nije bitno utjecala na metabolizam fermentacije te kakvoću plodova, a spriječila je njihovo propadanje tijekom skladištenja

In silico Transcriptional Regulatory Networks Involved in Tomato Fruit Ripening

ABSTRACTTomato fruit ripening is a complex developmental programme partly mediated by transcriptional regulatory networks. Several transcription factors (TFs) which are members of gene families such as MADS-box and ERF were shown to play a significant role in ripening through interconnections into an intricate network. The accumulation of large datasets of expression profiles corresponding to different stages of tomato fruit ripening and the availability of bioinformatics tools for their analysis provide an opportunity to identify TFs which might regulate gene clusters with similar co-expression patterns. We identified two TFs, a SlWRKY22-like and a SlER24 transcriptional activator which were shown to regulate modules by using the LeMoNe algorithm for the analysis of our microarray datasets representing four stages of fruit ripening, breaker, turning, pink and red ripe. The WRKY22-like module comprised a subgroup of six various calcium sensing transcripts with similar to the TF expression patterns according to real time PCR validation. A promoter motif search identified a cis acting element, the W-box, recognized by WRKY TFs that was present in the promoter region of all six calcium sensing genes. Moreover, publicly available microarray datasets of similar ripening stages were also analyzed with LeMoNe resulting in TFs such as SlERF.E1, SlERF.C1, SlERF.B2, SLERF.A2, SlWRKY24, SLWRKY37 and MADS-box/TM29 which might also play an important role in regulation of ripening. These results suggest that the SlWRKY22-like might be involved in the coordinated regulation of expression of the six calcium sensing genes. Conclusively the LeMoNe tool might lead to the identification of putative TF targets for further physiological analysis as regulators of tomato fruit ripening

Suppression of a Prolyl 4 Hydroxylase Results in Delayed Abscission of Overripe Tomato Fruits

The tomato pedicel abscission zone (AZ) is considered a model system for flower and fruit abscission development, activation, and progression. O-glycosylated proteins such as the Arabidopsis IDA (INFLORESCENCE DEFICIENT IN ABSCISSION) peptide and Arabinogalactan proteins (AGPs) which undergo proline hydroxylation were demonstrated to participate in abscission regulation. Considering that the frequency of occurrence of proline hydroxylation might determine the structure as well the function of such proteins, the expression of a tomato prolyl 4 hydroxylase, SlP4H3 (Solanum lycopersicum Prolyl 4 Hydroxylase 3) was suppressed in order to investigate the physiological significance of this post-translational modification in tomato abscission. Silencing of SlP4H3 resulted in the delay of abscission progression in overripe tomato fruits 90 days after the breaker stage. The cause of this delay was attributed to the downregulation of the expression of cell wall hydrolases such as SlTAPGs (tomato abscission polygalacturonases) and cellulases as well as expansins. In addition, minor changes were observed in the mRNA levels of two SlAGPs and one extensin. Moreover, structural changes were observed in the silenced SlP4H3AZs. The fracture plane of the AZ was curved and not along a line as in wild type and there was a lack of lignin deposition in the AZs of overripe fruits 30 days after breaker. These results suggest that proline hydroxylation might play a role in the regulation of tomato pedicel abscission

Synergistic exploitation of geoinformation methods for post-earthquake 3D mapping of Vrisa traditional settlement, Lesvos Island, Greece

The aim of this paper is to present the methodology followed and the results obtained by the synergistic exploitation of geo-information methods towards 3D mapping of the impact of the catastrophic earthquake of June 12th 2017 on the traditional settlement of Vrisa on the island of Lesvos, Greece. A campaign took place for collecting: a) more than 150 ground control points using an RTK system, b) more than 20.000 high-resolution terrestrial and aerial images using cameras and Unmanned Aircraft Systems and c) 140 point clouds by a 3D Terrestrial Laser Scanner. The Structure from Motion method has been applied on the high-resolution terrestrial and aerial photographs, for producing accurate and very detailed 3D models of the damaged buildings of the Vrisa settlement. Additionally, two Orthophoto maps and Digital Surface Models have been created, with a spatial resolution of 5cm and 3cm, respectively. The first orthophoto map has been created just one day after the earthquake, while the second one, a month later. In parallel, 3D laser scanning data have been exploited in order to validate the accuracy of the 3D models and the RTK measurements used for the geo-registration of all the above-mentioned datasets. The significant advantages of the proposed methodology are: a) the coverage of large scale areas; b) the production of 3D models having very high spatial resolution and c) the support of post-earthquake management and reconstruction processes of the Vrisa village, since such 3D information can serve all stakeholders, be it national and/or local organizations

Photoionization microscopy of the magnesium atom

Photoionization Microscopy (PM) is an experimental technique aiming at the observation of the squared modulus of the wave function of electrons emitted during the photoionization of neutral atoms in the presence of a uniform static electric field. This is achieved by imaging the two-dimensional flux of these slow (meV) photoelectrons. The present work is devoted to the magnesium atom (Z=12), ionized by two-photon absorption out of its ground state. Particularly, in this thesis the following three directions have been examined: The first direction concerns the recording and characterization of Mg resonant images. Indeed, images exhibiting resonant features are recorded just above the saddle point energy. Although these manifestations are found to be rather faint, they have been achieved for the heaviest atom so far, since all other resonant images were observed in small-size atoms (Z≤3). In the second direction, the aim is the detailed recording of the (primarily non-resonant) momentum distributions of the outgoing electron transversely to the static electric field. The purpose here is the exploration of the global (i.e. of that met in any atom and irrespective of excitation conditions) information these distributions may provide through the analysis of their rich interference patterns. Particularly, it is shown that the oscillations of the signal at the center of the images as a function of energy, is closely related to the dynamics of the electron motion towards the detector. Finally, in the third direction we explore the effects observed in slow photoelectron images when the linear polarization vector of the ionizing-laser is rotated with respect to the static field axis. It is shown that two-photon ionization out of the Mg m=0 initial state allows for the population of |m|=0,1,2 final Stark states, causing observable m-beating effects. Additionally, based on these observations, we discuss the challenges posed on the applicability of tomographic reconstruction techniques when meV electrons are involved. In all of the above directions, experimental results are supported and verified by our hydrogenic non-perturbative calculations.Η μικροσκοπία φωτοϊονισμού (ΜΦ) είναι μια από τις λίγες τον αριθμό τεχνικές οι οποίες στοχεύουν στην απευθείας καταγραφή του τετραγωνισμένου μέτρου της ηλεκτρονιακής κυματοσυνάρτησης (πυκνότητα πιθανότητας). Πιο συγκεκριμένα η ΜΦ είναι μια απεικονιστική τεχνική που επιτρέπει την καταγραφή της ροής του ηλεκτρονιακού ρεύματος, το οποίο εκπέμπεται κατά την διαδικασία φωτοϊονισμού ουδετέρων ατόμων, υπό την παρουσία στατικού και ομογενούς ηλεκτρικού πεδίου. Στην παρούσα εργασία η ΜΦ εφαρμόζεται στο άτομο του μαγνησίου, το οποίο ιονίζεται μέσω ενός διφωτονικού σχήματος διέγερσης ξεκινώντας από την βασική του κατάσταση. Τα πειραματικά δεδομένα υποστηρίζονται από υπολογισμούς στο άτομο του υδρογόνου, ενώ η μελέτη χωρίζεται σε τρεις επιμέρους άξονες: (i) Ο πρώτος άξονας αφορά στην καταγραφή και τον χαρακτηρισμό συντονιστικών καταστάσεων του μαγνησίου στην ενεργειακή περιοχή ακριβώς επάνω από την ενέργεια σαγματικού σημείου. Έτσι το μαγνήσιο αποτελεί το μεγαλύτερο άτομο για το οποίο έχει γίνει η παρατήρηση συντονιστικών χαρακτηριστικών. Παρ’ όλα αυτά τα χαρακτηριστικά αυτά βρέθηκαν να είναι λιγότερο εμφανή σε σχέση με τα αποτελέσματα προηγούμενων μελετών σε μικρά άτομα (Z≤3). (ii) Όσον αφορά στον δεύτερο άξονα, δίνεται έμφαση στη λεπτομερή καταγραφή των (κυρίως μη-συντονιστικών) κατανομών την ορμής των φωτοηλεκτρονίων, στην διεύθυνση κάθετα στο στατικό ηλεκτρικό πεδίο. Στόχος είναι η εξερεύνηση των καθολικών (ανεξαρτήτως του ατόμου στόχου) πληροφοριών, που μπορούν να εξαχθούν από την ανάλυση των μοτίβων συμβολής. Με αυτό τον τρόπο αποδεικνύεται πως οι ταλαντώσεις έντασης στο κέντρο των εικόνων ΜΦ ως συνάρτηση της ενέργειας συνδέονται με την δυναμική των φωτοηλεκτρονίων.και τέλος (iii) Μελετώνται τα παρατηρούμενα φαινόμενα που εμφανίζονται στις εικόνες ΜΦ όταν το διάνυσμα της γραμμικής πόλωσης της δέσμης laser στρέφεται σε σχέση με την διεύθυνση του στατικού ηλεκτρικού πεδίου. Αποδεικνύεται πως, ξεκινώντας από την βασική κατάσταση του μαγνησίου με m=0, η διφωτονική απορρόφηση οδηγεί στη διέγερση τελικών καταστάσεων Stark με |m|=0,1,2. Αυτές οι καταστάσεις πολλαπλών τιμών του |m|, συμβάλουν μεταξύ τους με αποτέλεσμα οι εικόνες ΜΦ να παρουσιάζουν μια περίπλοκη ακτινική και γωνιακή κατανομή. Τέλος, αναφορικά με τα παραπάνω αποτελέσματα, συζητούνται οι προκλήσεις που αντιμετωπίζουν οι τεχνικές τομογραφικής ανακατασκευής σε πειράματα όπου εμπλέκονται αργά ηλεκτρόνια

Pyridine 2,4-dicarboxylic acid suppresses tomato seedling growth

Pyridine 2,4-dicarboxylic acid is a structural analog of 2-oxoglutarate and is known to inhibit 2-oxoglutare-dependent dioxygenases. The effect of this inhibitor in tomato seedlings grown in MS media supplied with various concentrations of PDCA was investigated, resulting in shorter roots and hypocotyls in a dose-dependent manner. The partial inhibition of growth in roots was more drastic compared to hypocotyls and was attributed to a decrease in the elongation of root and hypocotyl cells. Concentrations of 100 and 250 μM of PDCA decreased hydroxyproline content in roots while only the 250 μM treatment reduced the hydroxyproline content in shoots. Seedlings treated with 100 μM PDCA exhibited enhanced growth of hypocotyl and cotyledon cells and higher hydroxyproline content resulting in cotyledons with greater surface area. However, no alterations in hypocotyl length were observed. Prolyl 4 hydroxylases (P4Hs) are involved in the O-glycosylation of AGPs and were also highly expressed during seedling growth. Moreover PDCA induced a decrease in the accumulation of HRGPs and particularly in AGPs-bound epitopes in a dose dependent-manner while more drastic reduction were observed in roots compared to shoots. In addition, bulged root epidermal cells were observed at the high concentration of 250 μM which is characteristic of root tissues with glycosylation defects. These results indicate that PDCA induced pleiotropic effects during seedling growth while further studies are required to better investigate the physiological significance of this 2-oxoglutarate analog. This pharmacological approach might be used as a tool to better understand the physiological significance of HRGPs and probably P4Hs in various growth and developmental programs in plants