Energy Balance During a Self-Sufficient, Multistage Ultramarathon

Endurance athletes are recommended to maintain energy balance and ensure adequate energy availability (EA) so that endurance performance is not compromised. Purpose: Describe and evaluate the energy balance of an athlete competing in a self-sufficient, multistage ultramarathon (MSU). Methods: A male endurance athlete (age 35 years; height 183.0 cm; body mass 78.4 kg; VO2max 66 ml/kg/min) volunteered to take part in this observational case study prior to competing in the Marathon des Sables (MdS) 2016. The subject self-reported energy intake (EI) by reviewing his dietary plan following each stage. Basal metabolic rate (BMR) was estimated prior to the MdS based on fat-free mass. Distance and moving speed were recorded using a GPS device throughout the race. Exercise energy expenditure (EEE) was calculated using the GPS device algorithm. Total energy expenditure (TEE) was calculated by adding the athlete’s BMR to the recorded EEE. Energy balance was calculated by subtracting EI from TEE. Results: Mean daily EI was 2946 ± 358 kcal and daily EEE was 3006 ± 1030 kcal. This resulted in a total energy deficit of 9609 kcal with a daily energy deficit of 1922 ± 952 kcal/day. The athlete did not report any subjective feelings of hunger at any point during the event. Conclusions: The athlete did not consume enough calories to meet estimated energy requirements, resulting in a negative energy balance and low EA throughout the event. Relying on subjective perception of hunger to modulate energy intake is an ineffective strategy during a MSU

A Portable MEMS Gravimeter for the Detection of the Earth Tides

Gravimeters are used for measuring the local gravitational acceleration. The use of current commercially available gravimeters, however, has been limited by their high cost and large size. In this study, a microelectromechanical system (MEMS) based relative gravimeter with an acceleration sensitivity of 8 μGall / √ (Hz) is demonstrated. The MEMS gravimeter, along with the custom interface electronics, is embedded on a battery powered portable platform. The portable platform enables continuous recording of the sensor response, while simultaneously measuring critical temperature and tilt parameters. To demonstrate the long-term stability of the system, the reported MEMS gravimeter platform was used to detect the Earth tides. In this paper, the first results from these measurements have been discussed

Heterogeneity in the histidine-brace copper coordination sphere in auxiliary activity family 10 (AA10) lytic polysaccharide monooxygenases

Copper-dependent lytic polysaccharide monooxygenases (LPMOs) are enzymes that oxidatively deconstruct polysaccharides. The active site copper in LPMOs is coordinated by a histidine-brace. This utilizes the amino group and side chain of the N-terminal His residue with the side chain of a second His residue to create a T-shaped arrangement of nitrogen ligands. We report a structural, kinetic, and thermodynamic appraisal of copper binding to the histidine-brace in an auxiliary activity family 10 (AA10) LPMO from Streptomyces lividans (SliLPMO10E). Unexpectedly, we discovered the existence of two apo-SliLPMO10E species in solution that can each bind copper at a single site with distinct kinetic and thermodynamic (exothermic and endothermic) properties. The experimental EPR spectrum of copper-bound SliLPMO10E requires the simulation of two different line shapes, implying two different copper-bound species, indicative of three and two nitrogen ligands coordinating the copper. Amino group coordination was probed through the creation of an N-terminal extension variant (SliLPMO10E- Ext). The kinetics and thermodynamics of copper binding to SliLPMO10E-Ext are in accord with copper binding to one of the apo-forms in the wild-type protein, suggesting that amino group coordination is absent in the two-nitrogen coordinate form of SliLPMO10E. Copper binding to SliLPMO10B was also investigated, and again it revealed the presence of two apo-forms with kinetics and stoichiometry of copper binding identical to that of SliLPMO10E. Our findings highlight that heterogeneity exists in the active site copper coordination sphere of LPMOs that may have implications for the mechanism of loading copper in the cell

Monitoring athletes sleep: A survey of current trends amongst practitioners

Achieving adequate sleep is considered important for athletic performance and recovery from exercise, yet the sleep monitoring methods applied amongst practitioners within highperformance sport are not well documented. This study aimed to identify the athlete sleep monitoring practices currently being implemented by practitioners working with full-time, junior (competing at the highest level), and semi-professional athletes. An online survey was developed and disseminated via email and social media to practitioners working with high-performance athletes. A sample of 145 practitioners completed the survey. Most (88%) practitioners rated sleep as ‘extremely important’ for recovery and performance (79%) and 84% of practitioners had advised athletes on improving sleep. The practitioners who reported monitoring sleep used several methods, including a questionnaire (37%), diary (26%) and actigraphy (19%). The most cited barrier to monitoring sleep was lack of time/resources. Most (79%) practitioners had not determined athletes’ chronotypes. Over half (54%) of the practitioners suggested their athletes did not get enough sleep outside of competition periods; the highest ranked suggested reason for this was screen time (i.e., using electronic devices). Practitioners recognise the importance of sleep for athletes and sleep education/monitoring was common amongst the practitioners; however, chronotype analysis was not widely used. Most practitioners used questionnaires and diaries to monitor athletes’ sleep and suggested that their athletes often experience insufficient sleep outside of competition periods

Alternative (backdoor) androgen production and masculinization in the human fetus

Funding: The study was supported by the following grants: Chief Scientist Office (Scottish Executive, CZG/4/742) (PAF and PJOS) (http://www.cso.scot.nhs.uk/funding-2/); NHS Grampian Endowments 08/02 (PAF and PJOS) and 15/1/010 (PAF, PF, US, and PJOS) (https://www.nhsgcharities.com/); the Glasgow Children’s Hospital Research Charity Research Fund, YRSS/PHD/2016/05 (NW, MB, PJOS, and PAF) (http://www.glasgowchildrenshospitalcharity.org/research/glasgow-childrens-hospital-charity-research-fund); the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement number 212885 (PAF) (https://ec.europa.eu/research/fp7/index_en.cfm); Medical Research Council Grants MR/L010011/1 (PAF and PJOS) and MR/K501335/1 (MB, PAF, and PJOS) (https://mrc.ukri.org/); and the Kronprinsessan Lovisas Foundation, “Stiftelsen Gunvor och Josef Anérs,” the “Stiftelsen Jane och Dan Olssons,” and the “Stiftelsen Tornspiran” (KS and OS). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

A mutation in the mitochondrial fission gene Dnm1l leads to cardiomyopathy

Mutations in a number of genes have been linked to inherited dilated cardiomyopathy (DCM). However, such mutations account for only a small proportion of the clinical cases emphasising the need for alternative discovery approaches to uncovering novel pathogenic mutations in hitherto unidentified pathways. Accordingly, as part of a large-scale N-ethyl-N-nitrosourea mutagenesis screen, we identified a mouse mutant, Python, which develops DCM. We demonstrate that the Python phenotype is attributable to a dominant fully penetrant mutation in the dynamin-1-like (Dnm1l) gene, which has been shown to be critical for mitochondrial fission. The C452F mutation is in a highly conserved region of the M domain of Dnm1l that alters protein interactions in a yeast two-hybrid system, suggesting that the mutation might alter intramolecular interactions within the Dnm1l monomer. Heterozygous Python fibroblasts exhibit abnormal mitochondria and peroxisomes. Homozygosity for the mutation results in the death of embryos midway though gestation. Heterozygous Python hearts show reduced levels of mitochondria enzyme complexes and suffer from cardiac ATP depletion. The resulting energy deficiency may contribute to cardiomyopathy. This is the first demonstration that a defect in a gene involved in mitochondrial remodelling can result in cardiomyopathy, showing that the function of this gene is needed for the maintenance of normal cellular function in a relatively tissue-specific manner. This disease model attests to the importance of mitochondrial remodelling in the heart; similar defects might underlie human heart muscle disease

Searching for a Stochastic Background of Gravitational Waves with LIGO

The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed the fourth science run, S4, with significantly improved interferometer sensitivities with respect to previous runs. Using data acquired during this science run, we place a limit on the amplitude of a stochastic background of gravitational waves. For a frequency independent spectrum, the new limit is $\Omega_{\rm GW} < 6.5 \times 10^{-5}$. This is currently the most sensitive result in the frequency range 51-150 Hz, with a factor of 13 improvement over the previous LIGO result. We discuss complementarity of the new result with other constraints on a stochastic background of gravitational waves, and we investigate implications of the new result for different models of this background.Comment: 37 pages, 16 figure

A mouse model with a frameshift mutation in the nuclear factor I/X (NFIX) gene has phenotypic features of Marshall-Smith syndrome

The nuclear factor I/X (NFIX) gene encodes a ubiquitously expressed transcription factor whose mutations lead to two allelic disorders characterized by developmental, skeletal, and neural abnormalities, namely, Malan syndrome (MAL) and Marshall–Smith syndrome (MSS). NFIX mutations associated with MAL mainly cluster in exon 2 and are cleared by nonsense-mediated decay (NMD) leading to NFIX haploinsufficiency, whereas NFIX mutations associated with MSS are clustered in exons 6–10 and escape NMD and result in the production of dominant-negative mutant NFIX proteins. Thus, different NFIX mutations have distinct consequences on NFIX expression. To elucidate the in vivo effects of MSS-associated NFIX exon 7 mutations, we used CRISPR-Cas9 to generate mouse models with exon 7 deletions that comprised: a frameshift deletion of two nucleotides (Nfix Del2); in-frame deletion of 24 nucleotides (Nfix Del24); and deletion of 140 nucleotides (Nfix Del140). Nfix+/Del2, Nfix+/Del24, Nfix+/Del140, NfixDel24/Del24, and NfixDel140/Del140 mice were viable, normal, and fertile, with no skeletal abnormalities, but NfixDel2/Del2 mice had significantly reduced viability (p Nfix Del2 was not cleared by NMD, and NfixDel2/Del2 mice, when compared to Nfix+/+ and Nfix+/Del2 mice, had: growth retardation; short stature with kyphosis; reduced skull length; marked porosity of the vertebrae with decreased vertebral and femoral bone mineral content; and reduced caudal vertebrae height and femur length. Plasma biochemistry analysis revealed NfixDel2/Del2 mice to have increased total alkaline phosphatase activity but decreased C-terminal telopeptide and procollagen-type-1-N-terminal propeptide concentrations compared to Nfix+/+ and Nfix+/Del2 mice. NfixDel2/Del2 mice were also found to have enlarged cerebral cortices and ventricular areas but smaller dentate gyrus compared to Nfix+/+ mice. Thus, NfixDel2/Del2 mice provide a model for studying the in vivo effects of NFIX mutants that escape NMD and result in developmental abnormalities of the skeletal and neural tissues that are associated with MSS

Cardiac fibrosis in aging mice

Dystrophic cardiac calcinosis (DCC), also called epicardial and myocardial fibrosis and mineralization, has been detected in mice of a number of laboratory inbred strains, most commonly C3H/HeJ and DBA/2J. In previous mouse breeding studies between these DCC susceptible and the DCC-resistant strain C57BL/6J, 4 genetic loci harboring genes involved in DCC inheritance were identified and subsequently termed Dyscalc loci 1 through 4. Here, we report susceptibility to cardiac fibrosis, a sub-phenotype of DCC, at 12 and 20 months of age and close to natural death in a survey of 28 inbred mouse strains. Eight strains showed cardiac fibrosis with highest frequency and severity in the moribund mice. Using genotype and phenotype information of the 28 investigated strains, we performed genome-wide association studies (GWAS) and identified the most significant associations on chromosome (Chr) 15 at 72 million base pairs (Mb) (P < 10(-13)) and Chr 4 at 122 Mb (P < 10(-11)) and 134 Mb (P < 10(-7)). At the Chr 15 locus, Col22a1 and Kcnk9 were identified. Both have been reported to be morphologically and functionally important in the heart muscle. The strongest Chr 4 associations were located approximately 6 Mb away from the Dyscalc 2 quantitative trait locus peak within the boundaries of the Extl1 gene and in close proximity to the Trim63 and Cap1 genes. In addition, a single-nucleotide polymorphism association was found on chromosome 11. This study provides evidence for more than the previously reported 4 genetic loci determining cardiac fibrosis and DCC. The study also highlights the power of GWAS in the mouse for dissecting complex genetic traits.The authors thank Jesse Hammer and Josiah Raddar for technical assistance. Research reported in this publication was supported by the Ellison Medical Foundation, Parker B. Francis Foundation, and the National Institutes of Health (R01AR055225 and K01AR064766). Mouse colonies were supported by the National Institutes of Health under Award Number AG025707 for the Jackson Aging Center. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. The Jackson Laboratory Shared Scientific Services were supported in part by a Basic Cancer Center Core Grant from the National Cancer Institute (CA34196).This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00335-016-9634-

Culture Adaptation Alters Transcriptional Hierarchies among Single Human Embryonic Stem Cells Reflecting Altered Patterns of Differentiation

We have used single cell transcriptome analysis to re-examine the substates of early passage, karyotypically Normal, and late passage, karyotypically Abnormal (‘Culture Adapted’) human embryonic stem cells characterized by differential expression of the cell surface marker antigen, SSEA3. The results confirmed that culture adaptation is associated with alterations to the dynamics of the SSEA3(+) and SSEA3(-) substates of these cells, with SSEA3(-) Adapted cells remaining within the stem cell compartment whereas the SSEA3(-) Normal cells appear to have differentiated. However, the single cell data reveal that these substates are characterized by further heterogeneity that changes on culture adaptation. Notably the Adapted population includes cells with a transcriptome substate suggestive of a shift to a more naïve-like phenotype in contrast to the cells of the Normal population. Further, a subset of the Normal SSEA3(+) cells expresses genes typical of endoderm differentiation, despite also expressing the undifferentiated stem cell genes, POU5F1 (OCT4) and NANOG, whereas such apparently lineage-primed cells are absent from the Adapted population. These results suggest that the selective growth advantage gained by genetically variant, culture adapted human embryonic stem cells may derive in part from a changed substate structure that influences their propensity for differentiation