Sedimentology, Stratigraphy and Micropaleontology of Pre- and Early-Champlain Sea Fine-Grained Facies from the Foster Sand Pit, Ottawa, Ontario

The Foster sand pit exposes pre- to late-Champlain Sea sediments containing 4 litho/biofacies. These are, from oldest to youngest: Faciès 1- cross-stratified sand and diamicton deposited as late-glacial, ice-proximal subaqueous outwash. Faciès 2- laminated silt and clay rhythmites with a sparse Candona cf. C. subtriangulata ostracode fauna deposited in a deep, proglacial lake preceding the Champlain Sea, Fades 3- massive to rarely laminated silty clay with dominant foraminifera Elphidium bartletti, Protelphidium orbiculare and Cassidulina crassa represents the first glaciomarine deposition in Champlain Sea water 30-100 m deep with a paleosalinity of 22-33 %o. Faciès 4- mixed bedding of sand and mud, with a microfossil assemblage dominated by the Elphidium/Protelphidium complex representing an intertidal offlap sequence. Water depths during deposition of Faciès 4 dropped to 10-30 m. and paleosalinity dropped to 18-28 %o.. This study recognizes a pre-Champlain Sea proglacial lake, assigns subaqueous outwash deposits to an earlier time than previously believed and documents changes in bottom water characteristics of the early Champlain Sea based on sedimentary and microfossil evidence.La sablière Foster laisse voir des sédiments glacio-lacustres et du début de la Mer de Champlain qui comprennent quatre litho-biofaciès. Les faciès, du plus vieux au plus récent, sont les suivants: Le faciès n° 1 est composé de sable et d'un diamicton à stratification oblique qui se présente comme un épandage fluvio-glaciaire subaquatique tardiglaciaire. Le faciès n° 2 est composé de silt laminé et de rythmites d'argile comprenant une faune peu abondante d'ostracodes {Candona cf. C. subtriangulata): ce faciès a été mis en place dans un lac proglaciaire profond qui a précédé la Mer de Champlain. Le faciès n° 3 est une argile silteuse d'aspect généralement massif avec quelques rares lamines renfermant les foraminifères Elphidium bartletti, Protelphidium orbiculare et Cassidulina crassa; ce faciès représente le premier dépôt de la Mer de Champlain mis en place à 30-100 m de profondeur; la paléosalinité était de 22-33 %o. Le faciès n° 4 formé de lits de sable et de boue mélangés, comprend un assemblage de microfossiles dominé par le complexe Elphidium - Protelphidium, qui représente une séquence intertidale de régression. Au cours de sa mise en place, la profondeur d'eau s'est abaissée jusqu'à 10-30 m, et les eaux se sont progressivement dessalées jusqu'à 18-28 %o. Dans cette étude, on reconnaît l'existence d'un lac proglaciaire précédant la Mer de Champlain. on attribue aux dépôts d'épandage subaquatique un âge supérieur à ce que l'on croyait auparavant et on fournit des renseignements sur le caractère changeant des eaux plus profondes du début de la Mer de Champlain fondés sur des preuves découlant de l'étude des sédiments et des microfossiles

The Late Glacial-Early Glaciomarine Transition in the Ottawa Valley: Evidence for a Glacial Lake?

Rhythmites overlying either cross-bedded sand or diamicton are found throughout the Ottawa Valley. Previously thought to be restricted glacial lake sediments, they are now known to be widespread, and represent a large proglacial lake which preceded the Champlain Sea. The rhythmites consist of thin silt and clay laminae which fine upwards and contain slump, flame, shear (ice-contact?) and fluid escape structures. Ice-rafted material is common. The ostracode Candona cf. C. subtriangulata occurs in low numbers and indicates a freshwater body with depth of approximately 200 m. The alternation of silt and clay rhythmite laminae is characteristic of deposition by underflow and overflow currents, respectively. To produce underflows with typical glacial outwash concentrations may require discharge into fresh rather than marine water. This evidence and the widespread occurrence of rhythmites throughout the Ottawa Valley and the Rideau Lakes area suggests a large proglacial lake as the sedimentary basin. The lake is tentatively correlated with the Belleville Phase of Glacial Lake Iroquois and the Ft. Ann Phase of Glacial Lake Vermont. These phases occurred at depths consistent with the requirements for Candona survival. The water body which existed in the Ottawa area is here called Lake Rideau after the type locality where rhythmites were first observed. Generation of such a lake favours the more conventional "window blind" model for déglaciation rather than the calving bay concept.On trouve tout au long de la vallée des Outaouais des rythmites qui recouvrent soit du sable en stratification oblique, soit un diamicton. On les a d'abord considérées comme des sédiments glacio-lacustres localisés, mais on sait maintenant qu'elles sont répandues et qu'elles témoignent de l'existence d'un grand lac glaciaire qui aurait précédé la Mer de Champlain. Les rythmites sont constituées de lamines de silt et d'argile qui s'affinent vers le haut et qui renferment des structures de glissement, en flamme, de cisaillement (de contact glaciaire?) et d'échappement fluidal. Les matériaux transportés par radeaux de glace sont courants. L'ostracode Candona cf. C. subtriangulata que l'on trouve en petit nombre témoigne de l'existence d'une nappe d'eau douce d'une profondeur d'environ 200 m. L'alternance de lamines rythmiques de silt et d'argile est caractéristique d'une mise en place par des courants de sous-écoulement et de débordement, respectivement. Pour qu'il y ait sous-écoulement accompagné de concentrations d'épandage fluvio-glaciaire. Ie déversement doit se faire en eaux douces plutôt qu'en milieu marin. Cet élément de preuve ajouté au fait que l'on trouve des rythmites partout dans la région de la vallée des Outaouais et des lacs Rideau laisse croire qu'un grand lac glaciaire a servi de bassin de sédimentation. À titre d'essai, on a établi la corrélation entre ce lac et la phase Belleville du Lac glaciaire Iroquois et la phase de Fort Ann du Lac glaciaire Vermont. Ces phases correspondent à des profondeurs d'eau conformes à la survie de Candona. On nomme ici Lac Rideau la nappe d'eau qui occupait la région d'Ottawa, d'après le site de référence où l'on a observé les premières rythmites. L'existence d'un tel lac favorise le modèle classique de retrait graduel des glaces plutôt que l'hypothèse des baies de vêlage.Das ganze Outaouais-Tal entlang findet man Rhythmite, die entweder diagonalgeschichteten Sand Oder Diamikton ùberlagern. Zuerst hielt man sie fur begrenzte glaziale See-Sedimente, aber jetzt weiss man, dass sie weit verbreitet sind und auf das Vorhandensein eines grossen glazialen Sees hinweisen, der sich dort vor dem Champlain-Meer befand. Die Rhythmite bestehen aus Schlamm- und Ton-Schichten, die sich nach oben verfeinern und Strukturen von Gleiten, Flammen, Abscherung (durch Eis-Kontakt?) und Flùssigkeitsentweichen enthalten. Es gibt hâufig durch Eis-Flosse transportiertes Material. Ostracode Candona wie auch C. subtriangulata, das man in kleinen Mengen findet, weist auf einen Sùsswasserspiegel von ungefàhr 200 m Tiefe hin. Der Wechsel zwischen rhythmischen Schichten von Schlamm und Ton ist charakteristisch fur eine Ablagerung durch Unterstrom- bzw. Ùberlaufstrômungen. Damit Unterstrom mitgleichzeitigen Konzentrationen von fluvioglazialer Aufschwemmung stattfindet, muss das Abfliessen eher in Sùsswasser als in Meereswasser geschehen. Dieser Nachweis und die Tatsache, dass man ùberall im Gebiet des Outaouais-Tals und der Rideau-Seen Rhythmite findet, erlaubt zu glauben, dass ein grosser glazialer See als Becken fur die Ablagerung gedient hat. Versuchsweise wurde eine Korrelation zwischen diesem See und der Belleville-Phase des glazialen Iroquois-Sees und der Fort Ann-Phase des glazialen Vermont-Sees erstellt. Dièse Phasen entsprechen Wassertiefen, die mit den Bedingungen fur das Ùberleben von Candona ùbereinstimmen. Rideau-See wird hier nach dem Modell-Standort, wo man die ersten Rhythmite bemerkt hat, die Wasserflâche genannt, die sich im Gebiet von Ottawa befand. Manuscrit reçu le 18 février 1987; manuscrit révisé accepté le 10 septembre 198

Bioactivity of Cooked Standard and Enriched Whole Eggs from White Leghorn and Rhode Island Red in Exhibiting In-Vitro Antioxidant and ACE-Inhibitory Effects

Hen breed, diet enrichment, cooking methods, and gastrointestinal (GI) digestion modulates the bioaccessibility of the bioactive compounds in eggs, but their synergistic role in modulating bioactivity is still unclear. The present study evaluates the effect of hen breed, diet enrichment, and GI digestion on the cooked whole egg-derived peptides in-vitro antioxidant and antihypertensive activities. Standard and enriched whole eggs from White Leghorn (WLH) and Rhode Island Red (RIR) hens were boiled or fried and subjected to GI digestion. Antioxidant activity was measured through oxygen radical absorbance capacity (ORAC) and gastrointestinal epithelial cell-based assays, and the antihypertensive capacity by in-vitro Angiotensin-I Converting Enzyme (ACE) inhibition assay. WLH fried standard egg hydrolysate showed a high ORAC antioxidant activity but failed to show any significant antioxidant effect in the cell-based assay. No significant differences were observed in the antihypertensive activity, although enriched samples tended to have a higher ACEinhibitory capacity. The peptide profile explained the antioxidant capacities based on antioxidant structural requirements from different peptide fractions, while previously reported antihypertensive peptides were found in all samples. The study validates the importance of physiologically relevant models and requires future studies to confirm mechanisms that yield bioactive compounds in whole egg hydrolysates

Reprogramming of sorghum proteome in response to sugarcane aphid infestation

Sugarcane aphid (SCA; Melanaphis sacchari Zehntner) is a key piercing-sucking pest of sorghum (Sorghum bicolor) that cause significant yield losses. While feeding on host plants, complex signaling networks are invoked from recognition of insect attack to induction of plant defenses. Consequently, these signaling networks lead to the production of insecticidal compounds or limited access of nutrients to insects. Previously, several studies were published on the transcriptomics analysis of sorghum in response to SCA infestation, but no information is available on the physiological changes of sorghum at the proteome level. We used the SCA resistant sorghum genotype SC265 for the global proteomics analysis after 1 and 7 days of SCA infestation using the TMT-plex technique. Peptides matching a total of 4211 proteins were identified and 158 proteins were differentially expressed at day 1 and 7. Overall, proteome profiling of SC265 after SCA infestation at days 1 and 7 revealed the suppression of plant defense-related proteins and upregulation of plant defense and signaling-related proteins, respectively. The plant defense responses based on proteome data were validated using electrical penetration graph (EPG) technique to observe changes in aphid feeding. Feeding behavior analyses revealed that SCA spent significantly longer time in phloem phase on SCA infested plants for day 1 and lesser time in day 7 SCA infested sorghum plants, compared to their respective control plants. Overall, our study provides insights into underlying mechanisms that contribute to sorghum resistance to SCA

Functional requirements for a Samd14-capping protein complex in stress erythropoiesis

Acute anemia induces rapid expansion of erythroid precursors and accelerated differentiation to replenish erythrocytes. Paracrine signals—involving cooperation between stem cell factor (SCF)/Kit signaling and other signaling inputs—are required for the increased erythroid precursor activity in anemia. Our prior work revealed that the sterile alpha motif (SAM) domain 14 (Samd14) gene increases the regenerative capacity of the erythroid system in a mouse genetic model and promotes stress-dependent Kit signaling. However, the mechanism underlying Samd14’s role in stress erythropoiesis is unknown. We identified a protein-protein interaction between Samd14 and the α- and β-heterodimers of the F-actin capping protein (CP) complex. Knockdown of the CP β subunit increased erythroid maturation in murine ex vivo cultures and decreased colony forming potential of stress erythroid precursors. In a genetic complementation assay for Samd14 activity, our results revealed that the Samd14-CP interaction is a determinant of erythroid precursor cell levels and function. Samd14-CP promotes SCF/Kit signaling in CD71med spleen erythroid precursors. Given the roles of Kit signaling in hematopoiesis and Samd14 in Kit pathway activation, this mechanism may have pathological implications in acute/chronic anemia

LncRNA Meg3 protects endothelial function by regulating the DNA damage response

The role of long non-coding RNAs (lncRNAs) in regulating endothelial function through the DNA damage response (DDR) remains poorly understood. In this study, we demonstrate that lncRNA maternally expressed gene 3 (Meg3) interacts with the RNA binding protein polypyrimidine tract binding protein 3 (PTBP3) to regulate gene expression and endothelial function through p53 signaling a major coordinator of apoptosis and cell proliferation triggered by the DDR. Meg3 expression is induced in endothelial cells (ECs) upon p53 activation. Meg3 silencing induces DNA damage, activates p53 signaling, increases the expression of p53 target genes, promotes EC apoptosis, and inhibits EC proliferation. Mechanistically, Meg3 silencing reduces the interaction of p53 with Mdm2, induces p53 expression, and promotes the association of p53 with the promoters of a subset of p53 target genes. PTBP3 silencing recapitulates the effects of Meg3 deficiency on the expression of p53 target genes, EC apoptosis and proliferation. The Meg3-dependent association of PTBP3 with the promoters of p53 target genes suggests that Meg3 and PTBP3 restrain p53 activation. Our studies reveal a novel role of Meg3 and PTBP3 in regulating p53 signaling and endothelial function, which may serve as novel targets for therapies to restore endothelial homeostasis

Variation in morpho‑physiological and metabolic responses to low nitrogen stress across the sorghum association panel

Background: Access to biologically available nitrogen is a key constraint on plant growth in both natural and agricultural settings. Variation in tolerance to nitrogen deficit stress and productivity in nitrogen limited conditions exists both within and between plant species. However, our understanding of changes in different phenotypes under long term low nitrogen stress and their impact on important agronomic traits, such as yield, is still limited. Results: Here we quantified variation in the metabolic, physiological, and morphological responses of a sorghum association panel assembled to represent global genetic diversity to long term, nitrogen deficit stress and the relationship of these responses to grain yield under both conditions. Grain yield exhibits substantial genotype by environment interaction while many other morphological and physiological traits exhibited consistent responses to nitrogen stress across the population. Large scale nontargeted metabolic profiling for a subset of lines in both conditions identified a range of metabolic responses to long term nitrogen deficit stress. Several metabolites were associated with yield under high and low nitrogen conditions. Conclusion: Our results highlight that grain yield in sorghum, unlike many morpho-physiological traits, exhibits substantial variability of genotype specific responses to long term low severity nitrogen deficit stress. Metabolic response to long term nitrogen stress shown higher proportion of variability explained by genotype specific responses than did morpho-pysiological traits and several metabolites were correlated with yield. This suggest, that it might be possible to build predictive models using metabolite abundance to estimate which sorghum genotypes will exhibit greater or lesser decreases in yield in response to nitrogen deficit, however further research needs to be done to evaluate such model

Lipid Droplet Membrane Proteome Remodeling Parallels Ethanol-Induced Hepatic Steatosis and its Resolution

Lipid droplets (LDs) are composed of neutral lipids enclosed in a phospholipid monolayer, which harbors membrane-associated proteins that regulate LD functions. Despite the crucial role of LDs in lipid metabolism, remodeling of LD protein composition in disease contexts, such as steatosis, remains poorly understood. We hypothesized that chronic ethanol consumption, subsequent abstinence from ethanol, or fasting differentially affects the LD membrane proteome content and that these changes influence how LDs interact with other intracellular organelles. Here, male Wistar rats were pair-fed liquid control or ethanol diets for 6 weeks, and then, randomly chosen animals from both groups were either refed a control diet for 7 days or fasted for 48 h before euthanizing. From all groups, LD membrane proteins from purified liver LDs were analyzed immunochemically and by MS proteomics. Liver LD numbers and sizes were greater in ethanol-fed rats than in pair-fed control, 7-day refed, or fasted rats. Compared with control rats, ethanol feeding markedly altered the LD membrane proteome, enriching LD structural perilipins and proteins involved in lipid biosynthesis, while lowering LD lipase levels. Ethanol feeding also lowered LD-associated mitochondrial and lysosomal proteins. In 7-day refed (i.e., ethanol-abstained) or fasted-ethanol-fed rats, we detected distinct remodeling of the LD proteome, as judged by lower levels of lipid biosynthetic proteins, and enhanced LD interaction with mitochondria and lysosomes. Our study reveals evidence of significant remodeling of the LD membrane proteome that regulates ethanol-induced steatosis, its resolution after withdrawal and abstinence, and changes in LD interactions with other intracellular organelles