How the ‘kitome’ influences the characterization of bacterial communities in lepidopteran samples with low bacterial biomass

Aims: We aimed to elucidate whether the DNA extraction kit and bacteria therein affect the characterization of bacterial communities associated with butterfly samples harbouring different bacterial abundancies. Methods and Results: We analysed bacteria associated with eggs of Pieris brassicae and with adults of this butterfly, which were either untreated or treated with antibiotics (ABs). Three DNA extraction kits were used. Regardless of the extraction kit used, PCR amplification of the bacterial 16S rRNA gene detected very low bacterial presence in eggs and AB‐treated butterflies. In untreated butterflies, bacterial signal intensity varied according to the kit and primers used. Sequencing (MiSeq) of the bacterial communities in untreated and AB‐treated butterflies revealed a low alpha diversity in untreated butterflies because of the dominance of few bacteria genera, which were detectable regardless of the kit. However, a significantly greater alpha diversity was found in AB‐treated butterflies, evidencing a true bias of the results due to bacterial contaminants in the kit. Conclusions: The so‐called ‘kitome’ can impact the profiling of Lepidoptera‐associated bacteria in samples with low bacterial biomass. Significance and Impact of the Study: Our study highlights the necessity of method testing and analysis of negative controls when investigating Lepidoptera‐associated bacterial communities

Priming by Timing: Arabidopsis thaliana Adjusts Its Priming Response to Lepidoptera Eggs to the Time of Larval Hatching

Plants can respond to eggs laid by herbivorous insects on their leaves by preparing (priming) their defense against the hatching larvae. Egg-mediated priming of defense is known for several plant species, including Brassicaceae. However, it is unknown yet for how long the eggs need to remain on a plant until a primed defense state is reached, which is ecologically manifested by reduced performance of the hatching larvae. To address this question, we used Arabidopsis thaliana, which carried eggs of the butterfly Pieris brassicae for 1-6 days prior to exposure to larval feeding. Our results show that larvae gained less biomass the longer the eggs had previously been on the plant. The strongest priming effect was obtained when eggs had been on the plant for 5 or 6 days, i.e., for (almost) the entire development time of the Pieris embryo inside the egg until larval hatching. Transcript levels of priming-responsive genes, levels of jasmonic acid-isoleucine (JA-Ile), and of the egg-inducible phytoalexin camalexin increased with the egg exposure time. Larval performance studies on mutant plants revealed that camalexin is dispensable for anti-herbivore defense against P. brassicae larvae, whereas JA-Ile - in concert with egg-induced salicylic acid (SA) - seems to be important for signaling egg-mediated primed defense. Thus, A. thaliana adjusts the kinetics of its egg-primed response to the time point of larval hatching. Hence, the plant is optimally prepared just in time prior to larval hatching

Placental CRH as a signal of pregnancy adversity and impact on fetal neurodevelopment

Early life is a period of considerable plasticity and vulnerability and insults during that period can disrupt the homeostatic equilibrium of the developing organism, resulting in adverse developmental programming and enhanced susceptibility to disease. Fetal exposure to prenatal stress can impede optimum brain development and deranged mother’s HPA axis stress responses can alter the neurodevelopmental trajectories of the offspring. Corticotropin-releasing hormone (CRH) and glucocorticoids, regulate fetal neurogenesis and while CRH exerts neuroprotective actions, increased levels of stress hormones have been associated with fetal brain structural alterations such as reduced cortical volume, impoverishment of neuronal density in the limbic brain areas and alterations in neuronal circuitry, synaptic plasticity, neurotransmission and GPCR signalling. Emerging evidence highlight the role of epigenetic changes in fetal brain programming, as stress-induced methylation of genes encoding molecules that are implicated in HPA axis and major neurodevelopmental processes. These serve as molecular memories and have been associated with long term modifications of the offspring’s stress regulatory system and increased susceptibility to psychosomatic disorders later in life. This review summarises our current understanding on the roles of CRH and other mediators of stress responses on fetal neurodevelopment

Metabolic phenotype of male obesity-related secondary hypogonadism pre-replacementand post-replacement therapy with intra-muscular testosterone undecanoate therapy

Aim: To explore the metabolic phenotype of obesity-related Secondary Hypogonadism (SH) in men pre- and post-replacement therapy with long-acting intramuscular (IM) testosterone undecanoate (TU). Methods: A prospective observational pilot study on metabolic effects of TU IM in male obesity-related SH (Hypogonadal [HG] group, n=13), including baseline comparisons with controls (Eugonadal [EG] group, n=15). Half the subjects (n=7 in each group) had Type 2 Diabetes Mellitus (T2D). Baseline metabolic assessment on Human Metabolism Research Unit: fasting blood samples; BodPod (body composition), and; whole-body indirect calorimetry. The HG group was treated with TU IM therapy for 6-29 months (mean 14.8-months [SD 8.7]), and assessment at the Human Metabolism Research Unit repeated. T-test comparisons were performed between baseline and follow-up data (HG group), and between baseline data (HG and EG groups). Data reported as mean (SD). Results: Overall, TU IM therapy resulted in a statistically significant improvement in HbA1C (9mmol/mol, P=0.03), with 52% improvement in HOMA%B. Improvement in glycaemic control was driven by the HG subgroup with T2D, with 18mmol/mol [P=0.02] improvement in HbA1C. Following TU IM therapy, there was a statistically significant reduction in fat mass (3.5Kg, P=0.03) and increase in lean body mass (2.9Kg, P=0.03). Lipid profiles and energy expenditure were unchanged following TU IM therapy. Comparisons between baseline data for HG and EG groups were equivalent apart from differences in testosterone, SHBG and BMR. Conclusion: In men with obesity-related SH (including a subgroup with T2D), TU IM therapy improved glycaemic control, beta cell function and body composition

Plant defensive responses to insect eggs are inducible by general egg-associated elicitors

Egg deposition by herbivorous insects is well known to elicit defensive plant responses. Our study aimed to elucidate the insect and plant species specificity of these responses. To study the insect species specificity, we treated Arabidopsis thaliana with egg extracts and egg-associated secretions of a sawfly (Diprion pini), a beetle (Xanthogaleruca luteola) and a butterfly (Pieris brassicae). All egg extracts elicited salicylic acid (SA) accumulation in the plant, and all secretions induced expression of plant genes known to be responsive to the butterfly eggs, among them Pathogenesis-Related (PR) genes. All secretions contained phosphatidylcholine derivatives, known elicitors of SA accumulation and PR gene expression in Arabidopsis. The sawfly egg extract did not induce plant camalexin levels, while the other extracts did. Our studies on the plant species specificity revealed that Solanum dulcamara and Ulmus minor responded with SA accumulation and cell death to P. brassicae eggs, i.e. responses also known for A. thaliana. However, the butterfly eggs induced neoplasms only in S. dulcamara. Our results provide evidence for general, phosphatidylcholine-based, egg-associated elicitors of plant responses and for conserved plant core responses to eggs, but also point to plant and insect species-specific traits in plant–insect egg interactions

Dietary Influences on the Microbiota–Gut–Brain Axis

Over unimaginable expanses of evolutionary time, our gut microbiota have co-evolved with us, creating a symbiotic relationship in which each is utterly dependent upon the other. Far from confined to the recesses of the alimentary tract, our gut microbiota engage in complex and bi-directional communication with their host, which have far-reaching implications for overall health, wellbeing and normal physiological functioning. Amongst such communication streams, the microbiota–gut–brain axis predominates. Numerous complex mechanisms involve direct effects of the microbiota, or indirect effects through the release and absorption of the metabolic by-products of the gut microbiota. Proposed mechanisms implicate mitochondrial function, the hypothalamus–pituitary–adrenal axis, and autonomic, neuro-humeral, entero-endocrine and immunomodulatory pathways. Furthermore, dietary composition influences the relative abundance of gut microbiota species. Recent human-based data reveal that dietary effects on the gut microbiota can occur rapidly, and that our gut microbiota reflect our diet at any given time, although much inter-individual variation pertains. Although most studies on the effects of dietary macronutrients on the gut microbiota report on associations with relative changes in the abundance of particular species of bacteria, in broad terms, our modern-day animal-based Westernized diets are relatively high in fats and proteins and impoverished in fibres. This creates a perfect storm within the gut in which dysbiosis promotes localized inflammation, enhanced gut wall permeability, increased production of lipopolysaccharides, chronic endotoxemia and a resultant low-grade systemic inflammatory milieu, a harbinger of metabolic dysfunction and many modern-day chronic illnesses. Research should further focus on the colony effects of the gut microbiota on health and wellbeing, and dysbiotic effects on pathogenic pathways. Finally, we should revise our view of the gut microbiota from that of a seething mass of microbes to one of organ-status, on which our health and wellbeing utterly depends. Future guidelines on lifestyle strategies for wellbeing should integrate advice on the optimal establishment and maintenance of a healthy gut microbiota through dietary and other means. Although we are what we eat, perhaps more importantly, we are what our gut microbiota thrive on and they thrive on what we eat

Maternal chronic stress correlates with serum levels of cortisol, glucose and C-peptide in the fetus, and maternal non chronic stress with fetal growth

Introduction: During pregnancy, maternal stressors cause changes in both maternal and fetal HPA axes. We therefore investigated the impact of maternal non chronic and chronic stress on fetal glucose metabolism and growth, and serum levels of cortisol in the fetus. Materials and methods: Normal weight pregnant women (n = 192; mean ± SD 27.9 ± 4.2 years old, and; 26.9 ± 2.4 kg/m²) were assessed during the 2nd and 3rd trimester with anthropometry, fetal ultrasound, blood samples for serum CRH, cortisol and IL6, and STAI trait and state stress questionnaires. We measured serum cortisol, insulin and c-peptide, and plasma glucose from cord blood. Neonates underwent anthropometry at the 3rd post-delivery day. Results: In both 2nd and 3rd trimesters, women with STAI trait scores ≥40 had significantly greater levels of fasting serum CRH and cortisol than those with STAI trait scores<40. 2nd trimester: STAI trait scores correlated positively with cord blood glucose and c-peptide. Maternal serum CRH correlated negatively with U/S fetal biparietal head diameter, while serum cortisol correlated positively with abdominal circumference. Maternal serum IL6, CRH and cortisol all correlated positively with birth waist circumference. 3rd trimester: Women with STAI state scores ≥40 had fetuses with larger U/S abdominal and smaller head circumferences compared to those of women with STAI scores <40. Women with STAI trait scores ≥40 had greater levels of cord blood cortisol, glucose, and c-peptide compared to women with STAI scores <40. STAI state scores ≥40 correlated positively with maternal CRH and U/S fetal abdominal circumference, and negatively with fetal head circumference and biparietal diameter. STAI trait scores correlated positively with cord blood c-peptide, glucose, insulin and cortisol. Maternal serum levels of CRH correlated positively with U/S fetal abdominal circumference and cord blood cortisol, and negatively with fetal head circumference and biparietal head diameter. Maternal serum levels of both CRH and cortisol correlated positively with cord blood c-peptide, glucose, and insulin. STAI trait was the best positive predictor of cord blood cortisol, glucose and c-peptide, whilst STAI state was the best positive and negative predictor, respectively of fetal abdominal circumference and fetal head circumference or biparietal diameter. Conclusions: Increased maternal chronic stress (reflected by the STAI trait score) associates with increased fetal cortisol, glucose, c-peptide secretion and thus, insulin resistance. Maternal non chronic stress (STAI state) in the 3rd trimester associates with changes in fetal growth pattern, including increased and decreased measurements of fetal abdominal and head growth respectively

Numerical solution of unsteady flow field on graphics processing unit and its depiction in "real" time

81 σ.Η διπλωματική εργασία έχει ως βασικό στόχο τη δημιουργία ενός επιλύτη μη-μόνιμης ροής που θα τρέχει στην κάρτα γραφικών (Graphics Processing Unit, GPU) ενός προσωπικού ηλεκτρονικού υπολογιστή. Πρόσθετο στόχο της αποτελεί η χρήση της κάρτας γραφικών για τη γραφική απεικόνιση του υπολογιζόμενου μη-μόνιμου πεδίου ροής, ταυτόχρονα με την επίλυσή του. Η χρήση καρτών γραφικών για επιτάχυνση της αριθμητικής επίλυσης μέσω της παράλληλης επεξεργασίας και της εκμετάλλευσης της μεγάλης υπολογιστικής δύναμης που αυτή διαθέτει έχει ήδη πραγματοποιηθεί από το Εργαστήριο Θερμικών Στροβιλομηχανών του ΕΜΠ με μεγάλη επιτυχία. Η επιτάχυνση μέχρι πρόσφατα έφτανε τις ~30 φορές ενώ με τις διαρκείς αλλαγές που πραγματοποιούνται, έχει σήμερα φτάσει τις ~50 φορές. Η επιτάχυνση οφείλεται στην πολλαπλάσια υπολογιστική δύναμη της κάρτας γραφικών σε σχέση με την κεντρική μονάδα επεξεργασίας (Central Processing Unit, CPU), όμως, ταυτόχρονα είναι αναγκαία η πλήρης αναμόρφωση του αντίστοιχου σειριακού κώδικα και απαιτεί ιδιαίτερη προσοχή στη διαχείριση της μικρής χωρητικότητας της μνήμης. Χρησιμοποιώντας ως βάση τον κώδικα του Εργαστηρίου Θερμικών Στροβιλομηχανών που αναλύει μόνιμες ροές σε κάρτες γραφικών, δημιουργήθηκε ο επιλύτης της εργασίας για μη-μόνιμες ροές επιδιώνοντας αντίστοιχου μεγέθους επιτάχυνση. Για την επεξεργασία μέσω της κάρτας γραφικών, χρησιμοποιήθηκε η γλώσσα CUDA της κατασκευάστριας εταιρίας Nvidia, ωστόσο υπάρχουν και άλλες μέθοδοι όπως η CTM της εταιρίας ATI. Η κάρτα γραφικών η οποία χρησιμοποιήθηκε, είναι η GeForce GTX 285 της Nvidia. Ο επιλύτης αφορά μη-μόνιμες, διδιάστατες και μη-συνεκτικες ροές και χρησιμοποιεί μη-δομημένο πλέγμα και κεντροκομβικό σύστημα. Εφαρμόστηκε για την επίλυση της ροής γύρω από μια μεμονωμένη συμμετρική αεροτομή NACA0012, με τη μη-μονιμότητα να προκαλείται μεταβάλλοντας την επ’άπειρον γωνία της ροής. Ένα ακόμα χαρακτηριστικό του κώδικα είναι η απεικόνιση του πεδίου ροής σε «πραγματικό» χρόνο. Λόγω της υψηλής ταχύτητας του επιλύτη χάριν της παράλληλης επεξεργασίας, θεωρήθηκε χρήσιμη η αναπαράσταση του πεδίου ροής ταυτόχρονα με τη λειτουργία του επιλύτη. Με αυτό το τρόπο, προτού ολοκληρωθεί η αριθμητική επίλυση του μη-μόνιμου πεδίου ροής για κάθε πραγματική χρονική στιγμή, ο κώδικας απεικονίζει το πεδίο ροής για τη προηγούμενη χρονική στιγμή, την οποία μόλις είχε επιλύσει. Για την επίτευξη της γραφικής απεικόνισης αναπτύχθηκε μια εφαρμογή της OpenGL.The purpose of this thesis is to create a solver of unsteady flow to perform its tasks on the Graphics Processing Unit (GPU) of a personal computer. An additional objective is to use the Graphics Processing Unit to display the calculated unsteady flow field, simultaneously with its solution. The use of Graphics Processing Unit to accelerate the numerical solution through parallel processing and exploitation of its large computing power, has already taken place in the laboratory of Thermal Turbomachines of NTUA with great success. The speeding up until recently reached the ~ 30 times while with the constant changes taking place, has now reached the ~ 50 times. The acceleration due to the multiple computing power of the Graphics Processing Unit compared to the CPU (Central Processing Unit, CPU), but it is necessary to restructure completely the corresponding serial code and requires extreme attention to the management of the small capacity memory. Using the code of the laboratory of Thermal Turbomachines, which analyses steady flows in Graphics Processing Units, a solver for unsteady flows was created, succeeding similar size and speed. For the use of the Graphics Processing Unit for processing the language of the manufacturer company CUDA Nvidia, but there are other methods such as CTM of the ATI company. The Graphics Processing Unit used for the application is GeForce GTX 285 Nvidia. The solver for unsteady, two dimensional and inviscid flows using non-structured grid and node-centered system. The solver is applied for a flow around a single symmetrical airfoil NACA0012. Another feature of this solver is the depiction of the flow field in "real" time. Thanks to the high speed of the solver the representation of the flow field simultaneously with the execution of the solver was considered useful. In this way, before the numerical solution of the unsteady flow field for each real time is completed, the code depicts the flow field of the last instance, which had just been resolved. For the depiction of the flow field an application of OpenGL was created.Γεώργιος Μ. Βαλσαμάκη