Απομόνωση και χαρακτηρισμός κατατεθειμένων στελεχών φυτοπλαγκτού (Τράπεζα Μικροφυκών) από παράκτια θαλάσσια συστήματα της Ανατολικής Μεσογείου

Τα πράσινα φυτά (green plants/Viridiplantae) είναι από τις πιο κυρίαρχες ομάδες πρωτογενών παραγωγών στη Γη. Περιλαμβάνουν τα «πράσινα» φύκη, καθώς και τα εμβρυόφυτα, κοινώς γνωστά ως τα φυτά της ξηράς. Τα «πράσινα» φύκη παρουσιάζουν μεγάλη ποικιλομορφία και είναι ευρέως διαδεδομένα σε υδάτινα και επίγεια περιβάλλοντα, έχουν μάλιστα διαδραματίσει έναν κρίσιμο ρόλο στο παγκόσμιο οικοσύστημα για εκατοντάδες εκατομμυρίων έτη (Falkowski et al. 2004, O’Kelly 2007, Leliaert et al. 2011). Αντιθέτως, τα φυτά της ξηράς είναι βασικά δομικά βιολογικά συστατικά των γήινων οικοσυστημάτων (Lewis & Mc Court 2004, O’Kelly 2007). Τα μικροφύκη είναι (1) ιδιαιτέρως ποικιλόμορφα, (2) συχνά αυτότροφα και (3) αρκετά ανεξερεύνητα. Ακόμη, φέρουν ιδιαίτερα χαρακτηριστικά στη φυσιολογία τους, που τα καθιστούν πολύ χρήσιμα στη φαρμακοβιομηχανία, στην ανθρώπινη διατροφή, στις υδατοκαλλιέργειες κλπ. Η ταξινομική, βιοχημική και μοριακή ταυτοποίηση των στελεχών αυτών είναι απαραίτητη, καθώς αποτελεί το πρώτο βήμα στη βέλτιστη χρήση τους τόσο για επιστημονικούς όσο και βιομηχανικούς σκοπούς. Στην παρουσιαζόμενη διπλωματική εργασία πραγματοποιήθηκε η απομόνωση, η καλλιέργεια, και ο βιοχημικός και μοριακός προσδιορισμός έντεκα (11) στελεχών μικροφυκών, τα οποία προέρχονται από παράκτια συστήματα της Ανατολικής Μεσόγειου και είναι κατατεθειμένα στην Τράπεζα Μικροφυκών του Τομέα Οικολογίας και Ταξινομικής του Τμήματος Βιολογίας του ΕΚΠΑ. Τα στελέχη που αναπτύσσονται στην Τράπεζα αυτή δυνητικά αποτελούν βάση για πιθανή αξιοποίησή τους σε υδατοκαλλιέργειες, στη βιομηχανία ή στην παραγωγή βιοκαυσίμων. Τα αποτελέσματα της εν λόγω διπλωματικής εργασίας, έδωσαν τη δυνατότητα να ταξινομηθεί σε επίπεδο γένους η πλειονότητα των επιλεγέντων στελεχών. Συγκεκριμένα, οκτώ (8) από τα στελέχη εντάχθηκαν ταξινομικά στο γένος Tetraselmis. στην οικογένεια Chlorodendrophyceae, ενώ τα υπόλοιπα τρία (3) στην οικογένεια Trebouxiophyceae, και ειδικότερα στα γένη Picochlorum, ή Nannochloris. Επιπλέον με την ανάλυση του βιοχημικού προφίλ των λιπαρών οξέων και των χρωστικών, ολοκληρώθηκε ο χαρακτηρισμός των στελεχών, ώστε αυτά δύνανται στο μέλλον να χρησιμοποιηθούν για περαιτέρω επιστημονικούς και εμπορικούς σκοπούς. Τέλος, η εργασία αυτή ανοίγει νέες προοπτικές για τη συστηματική και οικολογική μελέτη των μικροφυκών και συγκεκριμένα, υποδεικνύει την ανάγκη για την αναβάθμιση των κλειδών που χρησιμοποιούνται για τη μορφολογική παρατήρησή τους, για την αναζήτηση περισσότερων και κατάλληλων γονιδίων για τη μοριακή φυλογενετική μελέτη τους, αλλά και την περαιτέρω διερεύνηση των μηχανισμών που επηρεάζουν τη διαφοροποίηση και την εξέλιξη των οργανισμών αυτών, στα περιβάλλοντα όπου επιβιώνουν.The subkingdom of green plants (Viridiplantae) is one of the most dominant groups of primary producers on Earth. They include "green" algae, as well as embryophytes, commonly known as land plants. "Green" algae are highly diverse and widespread in aquatic and terrestrial environments and played a crucial role in the world ecosystem for hundreds of millions of years (Falkowski et al. 2004, O’Kelly 2007, Leliaert et al. 2011). On the contrary, land plants are essentially structural biological components of earth ecosystems (Lewis & McCourt 2004, O’Kelly 2007). Microalgae are (1) particularly variable, (2) often autotrophic and (3) quite unexplored. They also have particular characteristics in their physiology, making them very useful in the pharmaceutical industry, human nutrition, aquaculture, etc. The taxonomic, biochemical and molecular identification of these strains is essential, as it is the first step in their optimal use for both scientific as well as industrial purposes. In the presented diploma thesis the isolation, cultivation, and biochemical and molecular determination of eleven (11) microalgae strains were carried out, which originate from coastal systems of the Eastern Mediterranean, and were deposited at the Microalgae Bank of the Department of Ecology and Taxonomy (Faculty of Biology, NKUA). The strains deployed in this Bank are potentially the basis for their potential exploitation in aquaculture, industry or biofuel production. The results of this diploma thesis have made it possible to rank at the level of the majority of the selected strains. Specifically, eight (8) of the strains were taxonomically included in the genus Tetraselmis in the family Chlorodendrophyceae, while the remaining three (3) in the Trebouxiophyceae family, and in particular ihn the genera Picochlorum, or Nannochloris. In addition, with the analysis of the biochemical profile of fatty acids and pigments, the characterization of the strains has been completed so that these can be used in the future for further scientific and commercial purposes. Finally, this work opens up new perspectives for the systematic and ecological study of microalgae and indicates the need for upgrading the keys used for their morphological observation. Moreover, the search for more appropriate genes for a molecular phylogenetic study is necessary and for further exploring the mechanisms that affect the differentiation and evolution of these organisms in whatever environment they survive

New molecular methods to assess biodiversity. Potentials and pitfalls of DNA metabarcoding: a workshop report

This report presents the outcome of the joint work of PhD students and senior researchers working with DNA-based biodiversity assessment approaches with the goal to facilitate others the access to definitions and explanations about novel DNA-based methods. The work was performed during a PhD course (SLU PNS0169) at the Swedish University of Agricultural Sciences (SLU) in Uppsala, Sweden. The course was co-organized by the EU COST research network DNAqua-Net and the SLU Research Schools Focus on Soils and Water (FoSW) and Ecology - basics and applications. DNAqua-Net (COST Action CA15219, 2016-2020) is a network connecting researchers, water managers, politicians and other stakeholders with the aim to develop new genetic tools for bioassessment of aquatic ecosystems in Europe and beyond. The PhD course offered a comprehensive overview of the paradigm shift from traditional morphology-based species identification to novel identification approaches based on molecular markers. We covered the use of molecular tools in both basic research and applied use with a focus on aquatic ecosystem assessment, from species collection to the use of diversity in environmental legislation. The focus of the course was on DNA (meta)barcoding and aquatic organisms. The knowledge gained was shared with the general public by creating Wikipedia pages and through this collaborative Open Access publication, co-authored by all course participants

Time lags in reporting of biological invasions: the case of Mediterranean Sea

Time lags in non-indigenous species (NIS) reporting can create uncertainty in the analysis of NIS introduction rates, which can lead to inadequate prevention and management measures and their evaluation. The present study aims to highlight time lags in marine NIS reporting in the Mediterranean Sea, i.e. the time that mediates from the detection of a new NIS in the Mediterranean Sea until its publication. Our results revealed that the time lag in NIS reporting in the Mediterranean Sea has been considerably decreased during the last decades. There is a noticeable difference in the time lag of reporting NIS in association with the taxonomic group of the species. Fish have generally shorter time lags in their reporting when compared with other taxonomic groups (e.g. macrophytes, Annelida, Bryozoa). Time lags of NIS reporting need to be taken into account for more accurate assessments of introduction patterns of marine NIS and related management measures.JRC.D.2-Water and Marine Resource

Altered hippocampal connectivity dynamics predicts memory performance in neuropsychiatric lupus: a resting-state fMRI study using cross-recurrence quantification analysis

Objective Τo determine whole-brain and regional functional connectivity (FC) characteristics of patients with neuropsychiatric SLE (NPSLE) or without neuropsychiatric manifestations (non-NPSLE) and examine their association with cognitive performance.Methods Cross-recurrence quantification analysis (CRQA) of resting-state functional MRI (rs-fMRI) data was performed in 44 patients with NPSLE, 20 patients without NPSLE and 35 healthy controls (HCs). Volumetric analysis of total brain and specific cortical and subcortical regions, where significant connectivity changes were identified, was performed. Cognitive status of patients with NPSLE was assessed by neuropsychological tests. Group comparisons on nodal FC, global network metrics and regional volumetrics were conducted, and associations with cognitive performance were estimated (at p<0.05 false discovery rate corrected).Results FC in patients with NPSLE was characterised by increased modularity (mean (SD)=0.31 (0.06)) as compared with HCs (mean (SD)=0.27 (0.06); p=0.05), hypoconnectivity of the left (mean (SD)=0.06 (0.018)) and right hippocampi (mean (SD)=0.051 (0.0.16)), and of the right amygdala (mean (SD)=0.091 (0.039)), as compared with HCs (mean (SD)=0.075 (0.022), p=0.02; 0.065 (0.019), p=0.01; 0.14 (0.096), p=0.05, respectively). Hyperconnectivity of the left angular gyrus (NPSLE/HCs: mean (SD)=0.29 (0.26) and 0.10 (0.09); p=0.01), left (NPSLE/HCs: mean (SD)=0.16 (0.09) and 0.09 (0.05); p=0.01) and right superior parietal lobule (SPL) (NPSLE/HCs: mean (SD)=0.25 (0.19) and 0.13 (0.13), p=0.01) was noted in NPSLE versus HC groups. Among patients with NPSLE, verbal episodic memory scores were positively associated with connectivity (local efficiency) of the left hippocampus (r2=0.22, p=0.005) and negatively with local efficiency of the left angular gyrus (r2=0.24, p=0.003). Patients without NPSLE displayed hypoconnectivity of the right hippocampus (mean (SD)=0.056 (0.014)) and hyperconnectivity of the left angular gyrus (mean (SD)=0.25 (0.13)) and SPL (mean (SD)=0.17 (0.12)).Conclusion By using dynamic CRQA of the rs-fMRI data, distorted FC was found globally, as well as in medial temporal and parietal brain regions in patients with SLE, that correlated significantly and adversely with memory capacity in NPSLE. These results highlight the value of dynamic approaches to assessing impaired brain network function in patients with lupus with and without neuropsychiatric symptoms