The Comparative Methylome and Transcriptome After Change of Direction Compared to Straight Line Running Exercise in Human Skeletal Muscle.

The methylome and transcriptome signatures following exercise that are physiologically and metabolically relevant to sporting contexts such as team sports or health prescription scenarios (e.g., high intensity interval training/HIIT) has not been investigated. To explore this, we performed two different sport/exercise relevant high-intensity running protocols in five male sport team members using a repeated measures design of: (1) change of direction (COD) versus; (2) straight line (ST) running exercise with a wash-out period of at least 2 weeks between trials. Skeletal muscle biopsies collected from the vastus lateralis 30 min and 24 h post exercise, were assayed using 850K methylation arrays and a comparative analysis with recent (subject-unmatched) sprint and acute aerobic exercise meta-analysis transcriptomes was performed. Despite COD and ST exercise being matched for classically defined intensity measures (speed × distance and number of accelerations/decelerations), COD exercise elicited greater movement (GPS-Playerload), physiological (HR), metabolic (lactate) as well as central and peripheral (differential RPE) exertion measures compared with ST exercise, suggesting COD exercise evoked a higher exercise intensity. The exercise response alone across both conditions evoked extensive alterations in the methylome 30 min and 24 h post exercise, particularly in MAPK, AMPK and axon guidance pathways. COD evoked a considerably greater hypomethylated signature across the genome compared with ST exercise, particularly at 30 min post exercise, enriched in: Protein binding, MAPK, AMPK, insulin, and axon guidance pathways. Comparative methylome analysis with sprint running transcriptomes identified considerable overlap, with 49% of genes that were altered at the expression level also differentially methylated after COD exercise. After differential methylated region analysis, we observed that VEGFA and its downstream nuclear transcription factor, NR4A1 had enriched hypomethylation within their promoter regions. VEGFA and NR4A1 were also significantly upregulated in the sprint transcriptome and meta-analysis of exercise transcriptomes. We also confirmed increased gene expression of VEGFA, and considerably larger increases in the expression of canonical metabolic genes PPARGC1A (that encodes PGC1-α) and NR4A3 in COD vs. ST exercise. Overall, we demonstrate that increased physiological/metabolic load via COD exercise in human skeletal muscle evokes considerable epigenetic modifications that are associated with changes in expression of genes responsible for adaptation to exercise

Phylogenetic and Biogeographic Analysis of Sphaerexochine Trilobites

BACKGROUND: Sphaerexochinae is a speciose and widely distributed group of cheirurid trilobites. Their temporal range extends from the earliest Ordovician through the Silurian, and they survived the end Ordovician mass extinction event (the second largest mass extinction in Earth history). Prior to this study, the individual evolutionary relationships within the group had yet to be determined utilizing rigorous phylogenetic methods. Understanding these evolutionary relationships is important for producing a stable classification of the group, and will be useful in elucidating the effects the end Ordovician mass extinction had on the evolutionary and biogeographic history of the group. METHODOLOGY/PRINCIPAL FINDINGS: Cladistic parsimony analysis of cheirurid trilobites assigned to the subfamily Sphaerexochinae was conducted to evaluate phylogenetic patterns and produce a hypothesis of relationship for the group. This study utilized the program TNT, and the analysis included thirty-one taxa and thirty-nine characters. The results of this analysis were then used in a Lieberman-modified Brooks Parsimony Analysis to analyze biogeographic patterns during the Ordovician-Silurian. CONCLUSIONS/SIGNIFICANCE: The genus Sphaerexochus was found to be monophyletic, consisting of two smaller clades (one composed entirely of Ordovician species and another composed of Silurian and Ordovician species). By contrast, the genus Kawina was found to be paraphyletic. It is a basal grade that also contains taxa formerly assigned to Cydonocephalus. Phylogenetic patterns suggest Sphaerexochinae is a relatively distinctive trilobite clade because it appears to have been largely unaffected by the end Ordovician mass extinction. Finally, the biogeographic analysis yields two major conclusions about Sphaerexochus biogeography: Bohemia and Avalonia were close enough during the Silurian to exchange taxa; and during the Ordovician there was dispersal between Eastern Laurentia and the Yangtze block (South China) and between Eastern Laurentia and Avalonia

Stable Isotope Biogeochemistry of Seabird Guano Fertilization: Results from Growth Chamber Studies with Maize (Zea Mays)

Stable isotope analysis is being utilized with increasing regularity to examine a wide range of issues (diet, habitat use, migration) in ecology, geology, archaeology, and related disciplines. A crucial component to these studies is a thorough understanding of the range and causes of baseline isotopic variation, which is relatively poorly understood for nitrogen (δ(15)N). Animal excrement is known to impact plant δ(15)N values, but the effects of seabird guano have not been systematically studied from an agricultural or horticultural standpoint.This paper presents isotopic (δ(13)C and δ(15)N) and vital data for maize (Zea mays) fertilized with Peruvian seabird guano under controlled conditions. The level of (15)N enrichment in fertilized plants is very large, with δ(15)N values ranging between 25.5 and 44.7‰ depending on the tissue and amount of fertilizer applied; comparatively, control plant δ(15)N values ranged between -0.3 and 5.7‰. Intraplant and temporal variability in δ(15)N values were large, particularly for the guano-fertilized plants, which can be attributed to changes in the availability of guano-derived N over time, and the reliance of stored vs. absorbed N. Plant δ(13)C values were not significantly impacted by guano fertilization. High concentrations of seabird guano inhibited maize germination and maize growth. Moreover, high levels of seabird guano greatly impacted the N metabolism of the plants, resulting in significantly higher tissue N content, particularly in the stalk.The results presented in this study demonstrate the very large impact of seabird guano on maize δ(15)N values. The use of seabird guano as a fertilizer can thus be traced using stable isotope analysis in food chemistry applications (certification of organic inputs). Furthermore, the fertilization of maize with seabird guano creates an isotopic signature very similar to a high-trophic level marine resource, which must be considered when interpreting isotopic data from archaeological material

A new atmospherically relevant oxidant of sulphur dioxide

Atmospheric oxidation is a key phenomenon that connects atmospheric chemistry with globally challenging environmental issues, such as climate change, stratospheric ozone loss, acidification of soils and water, and health effects of air quality. Ozone, the hydroxyl radical and the nitrate radical are generally considered to be the dominant oxidants that initiate the removal of trace gases, including pollutants, from the atmosphere. Here we present atmospheric observations from a boreal forest region in Finland, supported by laboratory experiments and theoretical considerations, that allow us to identify another compound, probably a stabilized Criegee intermediate (a carbonyl oxide with two free-radical sites) or its derivative, which has a significant capacity to oxidize sulphur dioxide and potentially other trace gases. This compound probably enhances the reactivity of the atmosphere, particularly with regard to the production of sulphuric acid, and consequently atmospheric aerosol formation. Our findings suggest that this new atmospherically relevant oxidation route is important relative to oxidation by the hydroxyl radical, at least at moderate concentrations of that radical. We also find that the oxidation chemistry of this compound seems to be tightly linked to the presence of alkenes of biogenic origin

The influence of hydrogen core force shielding on dislocation junctions in iron

The influence of hydrogen on dislocation junctions was analysed by incorporating a hydrogen dependent core force into nodal based discrete dislocation dynamics. Hydrogen reduces the core energy of dislocations, which reduces the magnitude of the dislocation core force. We refer to this as hydrogen core force shielding, as it is analogous to hydrogen elastic shielding but occurs at much lower hydrogen concentrations. The dislocation core energy change due to hydrogen was calibrated at the atomic scale accounting for the nonlinear inter-atomic interactions at the dislocation core, giving the model a sound physical basis. Hydrogen was found to strengthen binary junctions and promote the nucleation of dislocations from triple junctions. Simulations of microcantilever bend tests with hydrogen core force shielding showed an increase in the junction density and subsequent hardening. These simulations were performed at a small hydrogen concentration realistic for bcc iron