Effect of maternal diet on offspring metabolic programming: changes induced by carbohydrate quality

Background Maternal diet and gestational diabetes have important implications for offspring health and disease. The fat mass and obesity associated gene (FTO) has the strongest relationship to increased body fat mass in humans, potentially via its effect on appetite and insulin sensitivity. Leptin plays a key role in regulating energy intake and expenditure, including appetite and hunger. Our hypothesis was that the expression of the Fto and leptin gene is influenced by the quality of carbohydrate in the maternal diet. Aim To compare glucose metabolism and mRNA expression of the Fto, leptin and other appetite-regulating genes in hypothalamic, adipose and/or other tissues of offspring of female mice fed high vs. low GI starch diets throughout pregnancy. Female C57BL/6 mice were randomly assigned to a low GI, high GI diet, or standard chow from 4 weeks of age and then mated with males who were fed the standard chow. In Study 1, male pups were weaned at the end of postnatal week 4 and divided into 2 subgroups, one following the chow diet and one their mother’s diet until 20 weeks of age. At week 20, the pups were sacrificed for tissue collection. In Study 2, female mice were sacrificed at gestation day 16-18 and placentas recovered. Tissues were analysed for gene expression and histological findings. Results Fto gene expression in the hypothalamus of offspring fed high GI starch from conception to postnatal week 20 was 2.5-fold higher than those fed low GI starch for the same time period (p = 0.01). Placental Fto gene expression was 3.8-fold higher in mothers fed the high GI starch diet vs. the low GI diet (p = 0.0003). By contrast, both early life and life-long exposure to a high GI diet were associated with lower Fto gene expression in white muscle. In the visceral adipose tissue, leptin gene expression was 3.3-fold higher in offspring exposed to the low GI diet from conception to week 20 and 4.4-fold higher in the offspring exposed to the low GI diet in early life. Plasma levels of the ‘hunger’ hormone ghrelin were significantly lower in offspring who received the low GI diet throughout life, while levels of the ‘satiety’ hormone leptin were higher. The co-expression of hypothalamic appetite genes AGRP/NPY and POMC/CART was also differentially regulated by the nature of the dietary carbohydrates. In this study, differences in diet, gene expression and hormone levels were not accompanied by differences in phenotype. Conclusion Carbohydrate quality, specifically the GI and/or rate of starch digestion in maternal diets, can differentially regulate the expression of the Fto and leptin gene in offspring tissues even in the absence of phenotypic differences. The nature of the dietary carbohydrates can regulate the co-expression of AGRP/NPY and POMC/CART in the hypothalamus. The findings imply that epigenetic changes induced in early life underlie observed differences in fat mass and insulin resistance in previous studies of high vs. low GI feeding. It is possible that changes in the nature of the carbohydrate in human diets may explain in part the current epidemic of obesity in children and adults

Τα θηλυκά σε -ος και τα προβλήματα στην κατάκτησή τους από μαθητές της Ε΄ και της ΣΤ΄

Η παρούσα εργασία επιχείρησε να εντοπίσει σε γραπτά μαθητών της Ε΄ και ΣΤ΄ δημοτικού αν υπάρχουν προβλήματα στην κατάκτηση των θηλυκών σε -ος, καθώς και τις αιτίες αυτών των προβλημάτων. Για τον εντοπισμό των προβλημάτων αυτών και των αιτιών τους αναλύθηκαν τα αποτελέσματα ενός πειράματος που διεξήχθη και αξιοποιήθηκε η σχετική βιβλιογραφία. Κατασκευάστηκε και δόθηκε ένα τεστ σε 93 μαθητές της Ε΄ και σε 125 μαθητές της ΣΤ΄ με μητρική γλώσσα την Ελληνική. Οι μαθητές καλούνταν να συμπληρώσουν [+ανθρώπινα] αλλά και [- ανθρώπινα] θηλυκά σε -ος στον κατάλληλο τύπο, να τονίσουν προπαροξύτονα τρικατάληκτα θηλυκά, να επιλέξουν τον ορθό τύπο τοπωνυμίων θηλυκού γένους με φωνητικό τέρμα -ος, να συμπληρώσουν επίθετα καθώς και το οριστικό άρθρο στη σωστή μορφή για να συνοδέψουν τα θηλυκά σε -ος. Τα τεστ διορθώθηκαν από την ερευνήτρια και μετρήθηκαν τα λάθη των παιδιών ανά άσκηση και ανά τύπο. Η ερευνήτρια ανέλυσε τα αριθμητικά δεδομένα με τη βοήθεια γραφημάτων στο Excel και διαπίστωσε την τάση των παιδιών να σχηματίζουν τα θηλυκά σε -ος με κλιτικά επιθήματα πρωτοτυπικών θηλυκών και να προτιμούν άσιγμη Ονομαστική Ενικού και ένσιγμη Γενική Ενικού. Ακόμα, ο μειωμένος αριθμός λαθών των μαθητών της ΣΤ΄ σε όλες τις ασκήσεις οδήγησε την ερευνήτρια στο συμπέρασμα ότι η επανάληψη αλλά και η γλωσσική ωρίμανση των μαθητών βελτίωσε τον βαθμό εμπέδωσης της λόγιας αυτής κλίσης.This study has attempted to detect in the students’ writings of 5th and 6th grade if there are problems in the acquisition of females ending in -os, as well as the causes of these problems. The results of an experiment, which was held, were analyzed and the relevant bibliography was exploited to spot these problems and their causes. A test, which was constructed, was given to 93 students of 5th grade and to 125 students of 6th grade in the mother tongue, which was the Greek one. The students were invited to fill in not only [+human] but also [-human] females ending in -os in the proper form, to accent on the females stressed on the antepenult, to choose the right form of female toponyms with phonetic ending -os, to supplement adjectives, as well as the definite article in the right form, in order to accompany the females in -os. The tests were corrected by the researcher and the children’s mistakes were counted per exercise and per form. The researcher analyzed the arithmetic data with the help of graphics in Excel and found out the children’s tendency to form females in -os with suffixes of prototypical females and the tendency to prefer nominative of Singular without ending in -s and genitive of Singular ending in -s. In addition, the reduced number of mistakes in the tests of the 6th grade in all the exercises leads the researcher to the conclusion that revision and the students’ linguistic maturity has improved the degree of the consolidation of this scholar inflection

A facile approach to hydrophilic oxidized fullerenes and their derivatives as cytotoxic agents and supports for nanobiocatalytic systems

A facile, environment-friendly, versatile and reproducible approach to the successful oxidation of fullerenes (oxC60) and the formation of highly hydrophilic fullerene derivatives is introduced. This synthesis relies on the widely known Staudenmaier’s method for the oxidation of graphite, to produce both epoxy and hydroxy groups on the surface of fullerenes (C60) and thereby improve the solubility of the fullerene in polar solvents (e.g. water). The presence of epoxy groups allows for further functionalization via nucleophilic substitution reactions to generate new fullerene derivatives, which can potentially lead to a wealth of applications in the areas of medicine, biology, and composite materials. In order to justify the potential of oxidized C60 derivatives for bio-applications, we investigated their cytotoxicity in vitro as well as their utilization as support in biocatalysis applications, taking the immobilization of laccase for the decolorization of synthetic industrial dyes as a trial case.Peer ReviewedPostprint (published version

Calmodulin Interacts and Regulates Enzyme Activity of the Mammalian Sperm Phospholipase C

Sperm-specific Phospholipase C zeta (PLCζ) is widely considered to be the sole, physiological stimulus responsible for the generation of Ca2+ oscillations that induce egg activation and early embryo development during mammalian fertilization. PLCζ, which is delivered from the fertilizing sperm into the egg cytoplasm, catalyzes the hydrolysis of its membrane-bound phospholipid substrate phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], triggering the cytoplasmic Ca2+ oscillations through the inositol 1,4,5-trisphosphate (InsP3) signaling pathway. Despite the recent advances the detailed regulatory mechanism of PLCζ is still unclear, as binding partners of this protein within the sperm or the fertilizing egg have not yet been identified. Calmodulin (CaM) is a ubiquitous Ca2+ sensor in eukaryotic cells. A previous study has reported that CaM directly interacts and regulates the activity of PLC delta 1 protein, a somatic PLC isoform with structural similarities to sperm PLCζ. Bioinformatics analysis revealed putative CaM-binding sites on PLCζ sequence. In the present study, we have used co-immunoprecipitation analysis and we show that in the presence of Ca2+, human PLCζ directly interacts with CaM. Isothermal titration calorimetry (ITC) experiments were performed to map the interaction. Three different peptides corresponding to disparate sequences within human PLCζ were used and it was shown that PLCζ interacts with CaM via one region of the molecule. In addition, recombinant proteins corresponding to the N- and C-lobe of human CaM were used for ITC experiments, which revealed that CaM interacts with PLCζ in the presence of Ca2+, only through one of its lobe domains. In vitro PIP2 hydrolysis assays revealed that CaM alters PLCζ PIP2 hydrolytic activity at high Ca2+ concentrations and, as suggested by liposome binding assays, this appears to be due to CaM binding to PLCζ affecting proper access of the enzyme active site to its substrate PI(4,5)P2

Essential role of the EF-hand domain in targeting sperm phospholipase Cζ to membrane phosphatidylinositol 4,5-bisphosphate (PIP2)

Sperm-specific phospholipase C-ζ (PLCζ) is widely considered to be the physiological stimulus that triggers intracellular Ca2+ oscillations and egg activation during mammalian fertilization. Although PLCζ is structurally similar to PLCδ1, it lacks a pleckstrin homology domain, and it remains unclear how PLCζ targets its phosphatidylinositol 4,5-bisphosphate (PIP2) membrane substrate. Recently, the PLCδ1 EF-hand domain was shown to bind to anionic phospholipids through a number of cationic residues, suggesting a potential mechanism for how PLCs might interact with their target membranes. Those critical cationic EF-hand residues in PLCδ1 are notably conserved in PLCζ. We investigated the potential role of these conserved cationic residues in PLCζ by generating a series of mutants that sequentially neutralized three positively charged residues (Lys-49, Lys-53, and Arg-57) within the mouse PLCζ EF-hand domain. Microinjection of the PLCζ EF-hand mutants into mouse eggs enabled their Ca2+ oscillation inducing activities to be compared with wild-type PLCζ. Furthermore, the mutant proteins were purified, and the in vitro PIP2 hydrolysis and binding properties were monitored. Our analysis suggests that PLCζ binds significantly to PIP2, but not to phosphatidic acid or phosphatidylserine, and that sequential reduction of the net positive charge within the first EF-hand domain of PLCζ significantly alters in vivo Ca2+ oscillation inducing activity and in vitro interaction with PIP2 without affecting its Ca2+ sensitivity. Our findings are consistent with theoretical predictions provided by a mathematical model that links oocyte Ca2+ frequency and the binding ability of different PLCζ mutants to PIP2. Moreover, a PLCζ mutant with mutations in the cationic residues within the first EF-hand domain and the XY linker region dramatically reduces the binding of PLCζ to PIP2, leading to complete abolishment of its Ca2+ oscillation inducing activity

Gallium-68 Labeled Iron Oxide Nanoparticles Coated with 2,3-Dicarboxypropane-1,1-diphosphonic Acid as a Potential PET/MR Imaging Agent: A Proof-of-Concept Study

The aim of this study was to develop a dual-modality PET/MR imaging probe by radiolabeling iron oxide magnetic nanoparticles (IONPs), surface functionalized with water soluble stabilizer 2,3-dicarboxypropane-1,1-diphosphonic acid (DPD), with the positron emitter Gallium-68. Magnetite nanoparticles (Fe3O4 MNPs) were synthesized via coprecipitation method and were stabilized with DPD. The Fe3O4-DPD MNPs were characterized based on their structure, morphology, size, surface charge, and magnetic properties. In vitro cytotoxicity studies showed reduced toxicity in normal cells, compared to cancer cells. Fe3O4-DPD MNPs were successfully labeled with Gallium-68 at high radiochemical purity ( GT 91%) and their stability in human serum and in PBS was demonstrated, along with their further characterization on size and magnetic properties. The ex vivo biodistribution studies in normal Swiss mice showed high uptake in the liver followed by spleen. The acquired PET images were in accordance with the ex vivo biodistribution results. Our findings indicate that 68 Ga-Fe3O4-DPD MNPs could serve as an important diagnostic tool for biomedical imaging

Synthesis, characterization and assessment of hydrophilic oxidized carbon nanodiscs in bio-related applications

Oxidation of industrially prepared carbon nanodiscs using a simple, versatile, and reproducible approach based on the Staudenmaier method yields a new hydrophilic form of nanocarbon. As a result of the strong acid treatment, which also enables the separation of carbon nanodiscs from the mixed starting material, the graphene planes detach from the discs, while the surface of the carbon nanodiscs is decorated with various oxygen-containing functional polar groups. Thus, the completely insoluble carbon nanodiscs are converted to a hydrophilic derivative dispersable in many polar solvents, including water. The new carbon structure is expected to have a wide range of applications in several fields including bioapplications. To this end, the functionalized carbon nanodiscs exhibit very low cytotoxicity, while they achieve high drug loadings, enabling their application as an effective drug nanocarrier. Furthermore, the carbon disks were evaluated as supports in nanobiocatalytic applications, increasing significantly the stability of the systems, due to carbon disks' nano-sized dimensions