Low resting metabolic rate is associated with greater lifespan because of a confounding effect of body fatness

Acknowledgments: This work was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) grant BB/C516228/1 to J.R.S. We thank Jackie Duncan and Sarah Johnston for helping with DNA protocol assays and Lobke Vaanholt for helping with antioxidant enzyme protocols. We are grateful to the staff of the animal house for the care of our animals and to Paula Redman and Peter Thomson who provided technical support for the DLW assays. Open Access: This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.Peer reviewedPublisher PD

Lifelongα-tocopherol supplementation increases the median life span of C57BL/6 mice in the cold but has only minor effects on oxidative damage

The effects of dietary antioxidant supplementation on oxidative stress and life span are confused. We maintained C57BL/6 mice at 7 ± 2°C and supplemented their diet with α-tocopherol from 4 months of age. Supplementation significantly increased (p = 0.042) median life span by 15% (785 days, n = 44) relative to unsupplemented controls (682 days, n = 43) and also increased maximum life span (oldest 10%, p = 0.028). No sex or sex by treatment interaction effects were observed on life span, with treatment having no effect on resting or daily metabolic rate. Lymphocyte and hepatocyte oxidative DNA damage and hepatic lipid peroxidation were unaffected by supplementation, but hepatic oxidative DNA damage increased with age. Using a cDNA macroarray, genes associated with xenobiotic metabolism were significantly upregulated in the livers of female mice at 6 months of age (2 months supplementation). At 22 months of age (18 months supplementation) this response had largely abated, but various genes linked to the p21 signaling pathway were upregulated at this time. We suggest that α-tocopherol may initially be metabolized as a xenobiotic, potentially explaining why previous studies observe a life span extension generally when lifelong supplementation is initiated early in life. The absence of any significant effect on oxidative damage suggests that the life span extension observed was not mediated via any antioxidant properties of α-tocopherol. We propose that the life span extension observed following α-tocopherol supplementation may be mediated via upregulation of cytochrome p450 genes after 2 months of supplementation and/or upregulation of p21 signaling genes after 18 months of supplementation. However, these signaling pathways now require further investigation to establish their exact role in life span extension following α-tocopherol supplementation

Thermoregulatory and cardiovascular responses to creatine, glycerol and alpha lipoic acid in trained cyclists

<p>Abstract</p> <p>Background</p> <p>It has been shown that supplementation with creatine (Cr) and glycerol (Gly), when combined with glucose (Glu) necessary for the enhancement of Cr uptake by skeletal muscle, induces significant improvements in thermoregulatory and cardiovascular responses during exercise in the heat.</p> <p>Purpose</p> <p>To determine whether Cr/Gly-induced thermoregulatory and cardiovascular responses are maintained when the majority (~75%) of the Glu in the Cr/Gly supplement is replaced with the insulintropic agent alpha lipoic acid (Ala).</p> <p>Methods</p> <p>22 healthy endurance trained cyclists were randomly assigned to receive either 20 g/day (4 × 5 g/day) of Cr, 2 g ^.kg^-1 BM per day (4 × 0.5 g ^.kg^-1 BM per day) of Gly and 150 g/day (4 × 37.5 g/day) of Glu or 20 g/day (4 × 5 g/day) of Cr monohydrate, 2 g ^.kg^-1 BM per day (4 × 0.5 g ^.kg^-1 BM per day) of Gly (100 g/day (4 × 25 g/day) of Glu and 1000 mg/day (4 × 250 mg/day) of Ala for 7 days for 7 days. Exercise trials were conducted pre- and post-supplementation and involved 40 min of constant-load cycling exercise at 70% O₂ max by a self-paced 16.1 km time trial at 30°C and 70% relative humidity.</p> <p>Results</p> <p>Median and range values of TBW increased significantly by 2.1 (1.3-3.3) L and 1.8 (0.2-4.6) L in Cr/Gly/Glu and Cr/Gly/Glu/Ala groups respectively (<it>P</it> = 0.03) and of BM not significantly by 1.8 (0.2-3.0) kg and 1.2 (0.5-2.1) kg in Cr/Gly/Glu and in Cr/Gly/Glu/Ala, respectively (<it>P</it> = 0.75). During constant load exercise, heart rate (HR) and core temperature (Tcore) were significantly lower post-supplementation: HR was reduced on average by 3.3 ± 2.1 beats/min and by 4.8 ± 3.3 beats/min (mean ± SD) and Tcore by 0.2 ± 0.1 (mean ± SD) in the Cr/Gly/Glu and Cr/Gly/Glu/Ala, respectively The reduction in HR and Tcore was not significantly different between the supplementation groups.</p> <p>Conclusions</p> <p>In comparison to the established hyper hydrating Cr/Gly/Glu supplement, supplement containing Cr/Gly/Ala and decreased amount of Glu provides equal improvements in thermoregulatory and cardiovascular responses during exercise in the heat.</p

Effects of dietary protein intake on lactation performance of the laboratory mouse, Mus musculus

Laboratory mice (strain MF1) were used to investigate the effects of dietary protein content on lactation performance to test the heat dissipation limit hypothesis. The specific dynamic action (SDA) for high protein (HP) and high carbohydrate (HC) diets was measured using open-flow respirometry at 9.4% and 6.1%, respectively. The same two diets were fed ad libitum to mice during lactation. Mice fed on HP and HC diets at 21 ºC reached a plateau in their daily food intake at 12.3±0.2 g day-1 and 16.6±0.2 g day-1, respectively between days 12-17 of lactation. HP-fed mice had a significantly higher daily energy expenditure (DEE) measured by doubly labelled water and higher water turnover than HC-fed mice but the energy they exported as milk was significantly lower than that of HC-fed mice and therefore resulted in poor growth rate of their offspring. The urea production of HP-fed mice from their daily protein intake of 7.1 g was estimated at 1994 mg which required 10.2 mls of water per day to be cleared. The mice increased their urine production by 14.4 mls probably to eliminate this urea. High protein diet had negative effects on lactation, indicating the growth of pups in previous studies was not protein limited. The negative effects of the HP diet were due to the high DEE that greatly reduced the energy available for milk production, rather than a toxicity effect of the urea production. The different DEE of the two diets suggests that other factors were involved in the delivery of energy to the offspring.KEY WORDS: Laboratory mouse, dietary protein, specific dynamic action, and daily energy expenditur

Effects of feeding fat on lactation performance of the laboratory mouse, Mus musculus

Laboratory mice (strain MF1) were used to investigate the effects of dietary fat intake on lactation performance. The specific dynamic action (SDA) for high fat (HF), medium fat (MF) and a low fat (LF) diets was measured using open-flow respirometry at 4.5%, 3.9% and 6.1%, respectively. The same three diets were fed ad libitum to mice between days 4 and 18 of lactation. Mice fed HF, MF and LF diets reached plateau in their daily food intake at 14.95±1.14 g day-1, 16.30±0.61 g day-1 and 16.57±0.26 g day-1, respectively between days 12-17 of lactation. At weaning, litters from HF and MF-fed mice were significantly heavier than pups on LF diet. This was because the HF and MF-fed mice not only consumed more energy at peak lactation but also delivered more milk energy to their pups than the LF-fed mice. Evidence suggested that the positive effects of feeding fat to mice were in part due to the low SDA and probably low heat production for milk synthesis. Probably, the ability of the HF and MF-fed mice to directly transfer absorbed fat into the milk might have reduced the heat production of lactogenesis. The HF and MF diets had beneficial effects on lactation because they increased the capacity of mice to generate milk more efficiently and wean heavier offspring than mice fed LF diet. The daily energy expenditure (DEE) of mice in the three dietary groups was fixed.KEY WORDS: Laboratory mouse, dietary fat, specific dynamic action, doubly labelled water, daily energy expenditure, milk energy output, reproductive performanc

Energetic Benefits of Sociality Offset the Costs of Parasitism in a Cooperative Mammal

We thank the owners for access to their property for animal capture and KwaZulu-Natal Nature Conservation Service for issuing the capture permit. This research was funded by the NRF-SAR Chair for Mammalian Behavioural Ecology and Physiology to NCB and University of Pretoria PDRF's to MS and HL. Many assistants were involved with fieldwork but we would especially like to thank Marietjie Oosthuizen and Craig Jackson for their help. This research was funded by the Department of Science and Technology/National Research Foundation-South African Research Chairs Initiative Chair for Mammalian Behavioural Ecology and Physiology to N.C.B. and University of Pretoria Postdoctoral Research Fellowships to M.S. and H.L. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Elevated O-GlcNAc levels activate epigenetically repressed genes and delay mouse ES cell differentiation without affecting naive to primed cell transition

The differentiation of mouse embryonic stem (ES) cells is controlled by the interaction of multiple signaling pathways, typically mediated by post-translational protein modifications. The addition of O-linked N-acetylglucosamine (O-GlcNAc) to serine and threonine residues of nuclear and cytoplasmic proteins is one such modification (O-GlcNAcylation), whose function in ES cells is only now beginning to be elucidated. Here we demonstrate that the specific inhibition of O-GlcNAc hydrolase (Oga) causes increased levels of protein O-GlcNAcylation and impairs differentiation of mouse ES cells both in serum-free monolayer and in embryoid bodies (EBs). Use of reporter cell lines demonstrates that Oga inhibition leads to a reduction in the number of Sox1-expressing neural progenitors generated following induction of neural differentiation, as well as maintained expression of the ES cell marker Oct4 (Pou5f1). In EBs expression of mesodermal and endodermal markers is also delayed. However, the transition of naïve cells to primed pluripotency indicated by Rex1 (Zfp42), Nanog, Esrrb and Dppa3 downregulation and Fgf5 upregulation remains unchanged. Finally, we demonstrate that increased O-GlcNAcylation results in upregulation of genes normally epigenetically silenced in ES cells, supporting the emerging role for this protein modification in the regulation of histone modifications and DNA methylation. Stem Cells 2014

Characterization of surface decorations in Prehispanic archaeological ceramics by Raman spectroscopy, FTIR, XRD and XRF

Non-invasive Raman microspectroscopy, FTIR, μXRD and XRF were used to identify the materials present in the black, red, and white surface decorations in selected pottery wares from two Prehispanic archaeological sites in Northwestern (NW) Argentina (AD 900?1530). The iron manganese spinel jacobsite, MnFe2O4, was found to be the main component of two of the fired black decorations analyzed, while hematite and amorphous silicates were found to be present in the red and white fired decorations, respectively. This is the first study, to our knowledge, that firmly identifies jacobsite in black decorations in Prehispanic archaeological ceramics. In fragments recovered from one site, a carbon-based black pigment was identified while gypsum was observed in the recessed areas of decorative surface incisions. Gypsum, potassium nitrate and halite, most likely deposited during burial, were observed on the surface of some of the fragments analyzed. The results are discussed in the context of the technological processes involved and are compared to compositions previously reported for decorations in ceramic objects from NW Argentina.Fil: Centeno, Silvia A.. The Metropolitan Museum of Art; Estados UnidosFil: Williams, Veronica Isabel. Universidad de Buenos Aires. Facultad de Filosofía y Letras. Instituto de Arqueología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Little, Nicole C.. Museum Conservation Institute; Estados UnidosFil: Speakman, Robert J.. Museum Conservation Institute; Estados Unido

The Assessment of Total Energy Expenditure During a 14-Day In-Season Period of Professional Rugby League Players Using the Doubly Labelled Water Method

Rugby League is a high-intensity collision sport competed over 80 min. Training loads are monitored to maximize recovery and assist in the design of nutritional strategies although no data are available on the total energy expenditure (TEE) of players. We therefore assessed resting metabolic rate (RMR) and TEE in six Super League players over 2 consecutive weeks in-season including one game per week. Fasted RMR was assessed followed by a baseline urine sample before oral administration of a bolus dose of hydrogen (deuterium 2H) and oxygen (18O) stable isotopes in the form of water (2H218O). Every 24 hr thereafter, players provided urine for analysis of TEE via DLW method. Individual training load was quantified using session rating of perceived exertion (sRPE) and data were analyzed using magnitude-based inferences. There were unclear differences in RMR between forwards and backs (7.7 ± 0.5 cf. 8.0 ± 0.3 MJ, respectively). Indirect calorimetry produced RMR values most likely lower than predictive equations (7.9 ± 0.4 cf. 9.2 ± 0.4 MJ, respectively). A most likely increase in TEE from Week 1 to 2 was observed (17.9 ± 2.1 cf. 24.2 ± 3.4 MJ) explained by a most likelyincrease in weekly sRPE (432 ± 19 cf. 555 ± 22 AU), respectively. The difference in TEE between forward and backs was unclear (21.6 ± 4.2 cf. 20.5 ± 4.9 MJ, respectively). We report greater TEE than previously reported in rugby that could be explained by the ability of DLW to account for all match and training-related activities that contributes to TEE