Peritoneal Cavity Regulatory B Cells (B10 Cells) Modulate IFN- +CD4+ T Cell Numbers during Colitis Development in Mice

The spleen regulatory B cell subset with the functional capacity to express IL-10 (B10 cells) modulates both immune responses and autoimmune disease severity. However, the peritoneal cavity also contains relatively high frequencies of functionally-defined IL-10-competent B10 cells. In this study, peritoneal cavity B10 cells shared similar cell surface phenotypes with their spleen counterparts. However, peritoneal cavity B10 cells were 10-fold more frequent among B cells than occurred within the spleen, intestinal track or mesenteric lymph nodes and were present at higher proportions among the phenotypically-defined peritoneal B1a>B1b>B2 cell subpopulations. The development or localization of B10 cells within the peritoneal cavity was not dependent on the presence of commensal microbiota, T cells, IL-10 or B10 cell IL-10 production, or differences between their fetal liver or adult bone marrow progenitor cell origins. The BCR repertoire of peritoneal cavity B10 cells was diverse, as occurs in the spleen, and predominantly included germline-encoded VH and VL regions commonly found in either the conventional or B1 B cell compartments. Thereby, the capacity to produce IL-10 appears to be an intrinsic functional property acquired by clonally diverse B cells. Importantly, IL-10 production by peritoneal cavity B cells significantly reduced disease severity in spontaneous and induced models of colitis by regulating neutrophil infiltration, colitogenic CD4+ T cell activation and pro-inflammatory cytokine production during colitis onset. Thus, the numerically small B10 cell subset within the peritoneal cavity has regulatory function and is important for maintaining homeostasis within gastrointestinal tissues and the immune system

Studying the impact of respiratory inhibitors in the metabolism of Aspergillus species, by applying molecular genetics and metabolomics

The aim of the doctoral dissertation is by using innovative "omics" techniques and the model organism Aspergillus nidulans, to study the mechanisms that affect the uptake, detoxification, and excretion of the fungicide boscalid, the main representative of the succinate dehydrogenase inhibitors. A strain genetically inactivated in all 7 genes encoding transporters that control the active uptake of purines showed reduced sensitivity to boscalid. After physiological and toxicological bioassays, the role of the UapC transporter in the active uptake of boscalid was found. The effect of boscalid on the metabolism of isogenetic strains expressing or genetically lacking boscalid-related nucleobase transporters by employing metabolomics was investigated. The effect of boscalid on the germination of conidiospores of the fungus was further investigated, first with a pilot study to understand the underlying mechanism, followed by the study of the toxicity of boscalid in it. The results showed a similar effect of d.o. as in the case of metabolic analysis of mycelial hyphae. To clarify the effect of SDHIs on the metabolism of the fungus, proteomic and metabolic analysis was applied. In boscalid presence an accumulation of succinate and reduced levels of fumarate was recorded, with increased levels of three of the four subunits of the target enzyme. Also, enzymes and metabolites with a role in detoxification, were expressed to address the toxic effect of boscalid. The fact that the expression of AtrB and AtrD ABC transporters seem to increase 6 days post-treatment, led to the study of their impact in boscalid toxicity. Strains were constructed with the corresponding genes deleted and overexpressed, followed by physiological and toxicological bioassays. The discovery of transporters involved in the active uptake or excretion of antifungal compounds that are poorly studied or even uncharacterized, is likely to lead to the discovery of new mechanisms of resistance. Additionally, the fact that trehalose hydrolysis proved to play an important role in the breakage of conidial dormancy, with the subsequent role of of glycerol in germination, highlights their biosynthetic pathways as promising targets for novel and improved PPPs.Στόχος της διδακτορικής διατριβής είναι μέσω της αξιοποίησης καινοτόμων “ομικών” τεχνικών και χρησιμοποιώντας τον πρότυπο ασκομύκητα Aspergillus nidulans, να μελετηθούν οι μηχανισμοί που επηρεάζουν την πρόσληψη, αποτοξικοποίηση και απέκκριση του μυκητοκτόνου boscalid, του κυριότερου εκπροσώπου της ομάδας των παρεμποδιστών της αφυδρογονάσης του ηλεκτρικού οξέος. Στέλεχος με διαγεγραμμένα επτά γονίδια που κωδικοποιούν μεταφορείς που ελέγχουν την ενεργή πρόσληψη πουρινών, εμφάνισε μειωμένη ευαισθησία στο boscalid. Έπειτα από φυσιολογικές και τοξικολογικές βιοδοκιμές, βρέθηκε ο ρόλος του UapC μεταφορέα στην ενεργή πρόσληψη της δ.ο., Με εφαρμογή μεταβολομικής μελετήθηκε η επίδραση του boscalid στο μεταβολισμό των ισογεννετικών στελεχών που υπερεκφράζουν ή έχουν διαγεγραμμένα γονίδια που κωδικοποιούν μεταφορείς πουρινών, οι οποίοι σχετίζονται με την πρόσληψη της δ.ο.. Διερευνήθηκε επιπλέον η επίδραση του boscalid στην εκβλάστηση των κονιδιοσπορίων του μύκητα, αρχικά με πιλοτικό πείραμα μελέτης και κατανόησης της φυσιολογίας της χρονικής της εξέλιξης και ακολούθως της μελέτης της τοξικότητας του boscalid σε αυτήν. Από τα αποτελέσματα φάηκε παρόμοια επίπτωση της δ.ο. όπως και στην περίπτωση της μεταβολομικής ανάλυσης των μυκηλιακών υφών. Προκειμένου να αποσαφηνιστεί η επίδραση της δ.ο. ακολούθησε πρωτεομική και μεταβολομική ανάλυση. Παρουσία της βρέθηκε συσσώρευση ηλεκτρικού και μειωμένα επίπεδα φουμαρικού οξέος και αυξημένα επίπεδα τριών εκ των τεσσάρων υπομονάδων του ενζύμου στόχου. Επίσης, ένζυμα και μεταβολίτες με ρόλο κατά την αποτοξικοποίηση, εκφράστηκαν ώστε να αντιμετωπιστεί η τοξική επίδραση της δ.ο.. Το γεγονός ότι η έκφραση των AtrB και AtrD ABC μεταφορέων, φαίνεται να αυξάνει στις 6 ημέρες, οδήγησε στη μελέτη της συσχέτισης της δράσης τους με την ευαισθησία στο boscalid. Κατασκευάστηκαν στελέχη με διαγεγραμμένα και υπερεκφρασμένα τα αντίστοιχα γονίδια και ακολούθησαν φυσιολογικές και τοξικολογικές βιοδοκιμές. Η ανακάλυψη για πρώτη φορά μεταφορέων που συμμετέχουν στην ενεργή προσρόφηση μυκητοκτόνων, αλλά και απεκκριτικών μεταφορέων μη μελετημένων, καθιστά πιθανή την ανακάλυψη νέων μηχανισμών ανθεκτικότητας. Επιπλέον, το γεγονός ότι η υδρόλυση της τρεχαλόζης βρέθηκε ότι παίζει σημαντικό ρόλο στην άρση του λήθαργου και ο μετέπειτα ρόλος της γλυκερόλης στην εκβλάστηση των κονιδιοσπορίων, υποδεικνύουν τα βιοσυνθετικά τους μονοπάτια ως πολλά υποσχόμενους στόχους για την ανάπτυξη νέας γενιάς Φ.Π

Metabolic Responses of Two Contrasting Lentil Genotypes to PEG-Induced Drought Stress

Among abiotic stresses, drought is undoubtedly one of the most severe environmental factors for a wide range of major crops, leading to considerable yield and economic losses. The adverse effects in crop yield reflect the result of a series of morphological and physiological changes but also changes in signaling pathways, transcriptional and post-transcriptional regulation of stress-responsive genes, and metabolic adaptations. Despite the exhausting studies elucidating plants’ metabolic response to drought, there is a knowledge gap in the biochemical mechanisms governing drought tolerance in lentil (Lens culinaris Medik.). The present study aimed to determine the fluctuations of the metabolite profiles of lentil genotypes with contrasting drought tolerance to discover possible biomarkers for screening tolerant genotypes at early growth stages. Lentil seedlings were subjected to osmotic drought stress, induced by polyethylene glycol, at two stress levels (2.5% and 5.0% PEG-6000) for a period of 20 days, while untreated plants were also included as controls. GC/ΕΙ/MS-mediated metabolic profiling was employed to monitor changes in response to osmotic drought stress. The data was subjected to OPLS-DA and OPLS-HCA for the discrimination between treatments and the discovery of trends and corresponding biomarkers. In total, the analysis yielded 150 metabolite features with highly reproducible patterns, of which the vast majority belonged to carbohydrates, carboxylic acids, and amino acids. Overall, findings highlight the differential accumulation of a series of compounds, and more importantly, the variable accumulation of certain metabolites, namely D-fructose, α,α-trehalose, myo-inositol, and L-tryptophan, in the contrasting genotypes, indicating that the adaptive metabolic responses to osmotic drought stress operate under strong genotypic dependency in lentil. Research findings provide insights into various aspects of lentil’s metabolism under drought and further offer the possibility of applying such knowledge towards effectively screening for drought-tolerant lentil germplasm at early growth stages

Metabolomic and Genomic Approach to Study Defense Induction by Nesidiocoris tenuis against Tuta absoluta and Tetranychus urticae in Tomato Plants

The phytophagy of the predator Nesidiocoris tenuis (Hemiptera: Miridae) can trigger defense responses in tomato plants against pests, such as two spotted spider mite Tetranychus urticae (Acari: Tetranychidae) and South American leaf miner Tuta absoluta (Lepidoptera: Gelechiidae). The expression of genes governing Jasmonic Acid (JA) biosynthesis pathway and fluctuations in the levels of underlying metabolites have been rarely studied in mirid-infested plants. In the present study, fifteen 3rd instar nymphs of N.tenuis were caged on each top and lower leaf of tomato plants for 4 d to induce plant defense; after this period the predators were removed. With regard to T. absoluta, oviposition preference; larval period; and pupal weight were significantly reduced in N. tenuis-punctured plants. T. urticae adults exhibited a significantly higher escape tendency and reduced survival on punctured plants. Metabolomics confirmed such observations revealing substantial differences between N. tenuis-punctured and unpunctured (control) plants. Metabolites directly associated with the activation of the JA defense pathway, such as the precursor α-linolenic acid, had increased concentrations. The expression of the defense-related genes PI-II, MYC2, VSP2, and HEL was increased in the top leaves and only VSP2 and MBP2 in the lower leaves; interestingly, in the middle (unpunctured) leaves VSP2, HEL, and MBP2 were also upregulated, indicating systemic signaling. Collectively, phytophagy of N. tenuis caused adverse effects on T. absoluta and T. urticae, whereas the multi-omics approach (phenomics, metabolomics, and genomics) offered valuable insights into the nature of the plant defense responses and provided useful evidence for future applications in integrated pest management, plausibly resulting in the reduction in the required pesticide volumes

Nondetectable Prostate Carcinoma (pT0) after Radical Prostatectomy: A Narrative Review

(1) Background: Following radical prostatectomy (RP), the absence of a demonstrable tumor on the specimen of a previously histologically proven malignancy is known as the pT0 stage. The aim of our present study is to perform a narrative review of current literature in order to determine the frequency and oncological outcomes in patients with pT0 disease. (2) Methods: A narrative review of all available literature was performed. (3) Results: The incidence of pT0 ranges between 0.07% and 1.3%. Predictors of the pT0 stage are only a single biopsy core with low-grade cancer, a cancer length not exceeding 2 mm and a high prostate volume. Biochemical recurrence ranges between 0 and 11%. (4) Conclusions: The absence of malignancy in the RP specimen despite a previous positive biopsy is a rare and unpredictable finding. Although the prognosis is considered to be excellent in most of the cases, a continued close follow-up is warranted