Acute Exercise Increases Adiponectin Levels in Abdominally Obese Men

Objective. To examine the effect of acute and short-term (~1 week) aerobic exercise training on plasma adiponectin levels in inactive, abdominally obese men. Materials and Methods. Inactive and abdominally obese men (n = 38, waist circumference ≥102 cm) recruited from Kingston, Canada were randomly allocated to perform three bouts of aerobic treadmill exercise at either low (50% VO2 peak) or high (75% VO2 peak) intensity during a 1-week period. Blood samples were taken before and after the first exercise session and 24–72 hours following the completion of the final exercise session. Results. Adiponectin levels were elevated immediately following an acute bout of exercise at both high and low intensities (High: 5.79 ± 0.42 versus 5.05 ± 0.41 ug/mL; Low: 5.24 ± 0.44 versus 4.37 ± 0.44 ug/mL, P < 0.05) and remained elevated following 30 minutes of rest. In comparison to baseline, adiponectin levels were also elevated 24–72 hours following the final exercise session (High: 5.47 ± 0.48 versus 4.88 ± 0.48 ug/mL; Low: 5.18 ± 0.49 versus 4.47 ± 0.49 ug/mL, P < 0.05). Conclusion. Both acute and short-term aerobic exercise result in a significant increase in plasma adiponectin levels in inactive, abdominally obese men independent of intensity

Acute Exercise Increases Adiponectin Levels in Abdominally Obese Men

Objective. To examine the effect of acute and short-term (~1 week) aerobic exercise training on plasma adiponectin levels in inactive, abdominally obese men. Materials and Methods. Inactive and abdominally obese men (n = 38, waist circumference ≥102 cm) recruited from Kingston, Canada were randomly allocated to perform three bouts of aerobic treadmill exercise at either low (50% VO2 peak) or high (75% VO2 peak) intensity during a 1-week period. Blood samples were taken before and after the first exercise session and 24–72 hours following the completion of the final exercise session. Results. Adiponectin levels were elevated immediately following an acute bout of exercise at both high and low intensities (High: 5.79 ± 0.42 versus 5.05 ± 0.41 ug/mL; Low: 5.24 ± 0.44 versus 4.37 ± 0.44 ug/mL, P < 0.05) and remained elevated following 30 minutes of rest. In comparison to baseline, adiponectin levels were also elevated 24–72 hours following the final exercise session (High: 5.47 ± 0.48 versus 4.88 ± 0.48 ug/mL; Low: 5.18 ± 0.49 versus 4.47 ± 0.49 ug/mL, P < 0.05). Conclusion. Both acute and short-term aerobic exercise result in a significant increase in plasma adiponectin levels in inactive, abdominally obese men independent of intensity

Herschel observations of EXtraordinary Sources: Analysis of the full Herschel/HIFI molecular line survey of Sagittarius B2(N)

A sensitive broadband molecular line survey of the Sagittarius B2(N) star-forming region has been obtained with the HIFI instrument on the Herschel Space Observatory, offering the first high-spectral resolution look at this well-studied source in a wavelength region largely inaccessible from the ground (625-157 um). From the roughly 8,000 spectral features in the survey, a total of 72 isotopologues arising from 44 different molecules have been identified, ranging from light hydrides to complex organics, and arising from a variety of environments from cold and diffuse to hot and dense gas. We present an LTE model to the spectral signatures of each molecule, constraining the source sizes for hot core species with complementary SMA interferometric observations, and assuming that molecules with related functional group composition are cospatial. For each molecule, a single model is given to fit all of the emission and absorption features of that species across the entire 480-1910 GHz spectral range, accounting for multiple temperature and velocity components when needed to describe the spectrum. As with other HIFI surveys toward massive star forming regions, methanol is found to contribute more integrated line intensity to the spectrum than any other species. We discuss the molecular abundances derived for the hot core, where the local thermodynamic equilibrium approximation is generally found to describe the spectrum well, in comparison to abundances derived for the same molecules in the Orion KL region from a similar HIFI survey.Comment: Accepted to ApJ. 64 pages, 14 figures. Truncated abstrac

Roles of forest bioproductivity, transpiration and fire in a nine-year record of cave dripwater chemistry from southwest Australia

Forest biomass has the potential to significantly impact the chemistry and volume of diffuse recharge to cave dripwater via the processes of nutrient uptake, transpiration and forest fire. Yet to-date, this role has been under-appreciated in the interpretation of speleothem trace element records from forested catchments. In this study, the impact of vegetation is examined and quantified in a long-term monitoring program from Golgotha Cave, SW Australia. The contribution of salts from rain and dry-deposition of aerosols and dissolved elements from soil mineral and bedrock dissolution to dripwater chemistry are also examined. This study is an essential pre-requisite for the future interpretation of trace element data from SW Australian stalagmite records, whose record of past environmental change will include alterations in these biogeochemical fluxes. Solute concentrations in dripwater vary spatially, supporting the existence of distinct flow paths governed by varying amounts of transpiration as well as nutrient uptake by deeply-rooted biomass. Applying principal components analysis, we identify a common pattern of variation in dripwater Cl, Mg, K, Ca, Sr and Si, interpreted as reflecting increasing transpiration, due to forest growth. Mass-balance calculations show that increasing elemental sequestration into biomass has the largest impact on SO4, providing an explanation for the overall falling dripwater SO4 concentrations through time, in contrast to the transpiration-driven rising trend dominating other ions. The long-term rise in transpiration and nutrient uptake driven by increased forest bioproductivity and its impact on our dripwater chemistry is attributed to i. the post-fire recovery of the forest understorey after fire impacted the site in 2006 CE; ii. and/or increased water and nutrient demand as trees in the overlying forest mature. The impact of climate-driven changes on the water balance is also examined. Finally, the implications for interpreting SW Australian speleothem trace element records are discussed

In Vivo Fluorescent Detection of Fe-S Clusters Coordinated by Human GRX2

A major challenge to studying Fe-S cluster biosynthesis in higher eukaryotes is the lack of simple tools for imaging metallocluster binding to proteins. We describe the first fluorescent approach for in vivo detection of 2Fe2S clusters that is based upon the complementation of Venus fluorescent protein fragments via human glutaredoxin 2 (GRX2) coordination of a 2Fe2S cluster. We show that Escherichia coli and mammalian cells expressing Venus fragments fused to GRX2 exhibit greater fluorescence than cells expressing fragments fused to a C37A mutant that cannot coordinate a metallocluster. In addition, we find that maximal fluorescence in the cytosol of mammalian cells requires the iron-sulfur cluster assembly proteins ISCU and NFS1. These findings provide evidence that glutaredoxins can dimerize within mammalian cells through coordination of a 2Fe2S cluster as observed with purified recombinant proteins

The Permafrost Regionalization Map (PeRM): How well do observations, models and experiments represent the circumarctic-scale spatial variability in permafrost carbon vulnerability?

A large amount of organic carbon stored in permafrost soils across the high latitudes is vulnerable to thaw, decomposition and release to the atmosphere as a result of climate warming. Findings from observational, experimental and modeling studies all suggest that this process could lead to a significant positive feedback on future radiative forcing from terrestrial ecosystems to the Earth’s climate system. With respect to the magnitude and timing of this feedback, however, observational data show large variability across sites, experimental studies are few, and different models result in a wide range of responses. These issues represent fundamental limitations on improving our confidence in projecting future permafrost carbon release and associated climate feedbacks. Recent studies have brought new insight into – and even quantitative estimates for – these issues through broader data synthesis and model-data integration approaches. But, how representative of the circumarcticscale variability in permafrost carbon vulnerability are the data and models from these studies? To address this question, we developed a geospatial data synthesis and analysis framework designed to represent and characterize the variability in permafrost carbon vulnerability across the northern high latitudes. Here, we describe the rationale and methods used to develop the regionalization scheme, and then use the framework to assess the spatial representativeness of, and the variability described by, existing data sets defining the fundamental components and environmental drivers of permafrost carbon vulnerability. The Permafrost Regionalization Map (PeRM) considers the regional-scale environmental factors that generally determine the spatial variability in permafrost carbon vulnerability across the Arctic. The broadly-defined regional classification is based on a circumarctic spatial representation of the major environmental controls on a) the rate and extent of permafrost degradation and thaw, b) the quantity and quality of soil organic matter stocks, and c) the form of permafrost carbon emissions as CO2 and CH4. We chose a generalized, pragmatic approach that resulted in a feasible number of regional subdivisions (i.e.,‘reporting units’) based on an intersection of spatial data layers according to permafrost extent, permafrost distribution, climate regime, biome and terrain. The utility of the PeRM framework is demonstrated here through areal density analysis and spatial summaries of existing data collections describing the fundamental components of permafrost carbon vulnerability. We use this framework to describe the spatial representativeness and variability in measurements within and across PeRM regions using observational data sets describing active layer thickness, soil pedons and carbon storage, long-term incubations for carbon turnover rates, and site-level monitoring of CO2 and CH4 fluxes from arctic tundra and boreal forest ecosystems. We then use these regional summaries of the observational data to benchmark the results of a process-based biogeochemical model for its skill in representing the magnitudes and spatial variability in these key indicators. Finally, we discuss the on-going use of this framework as a basis for higher-resolution mapping of key regions of particular vulnerability to both press (active layer thickening) and pulse (thermokarst development) disturbances. This work is guiding on-going research toward characterizing permafrost degradation and associated vegetation changes through multi-scale remote sensing. Overall, this spatial data synthesis framework work provides a critical bridge between the abundant but disordered observational and experimental data collections and the development of higher-complexity process representation of the permafrost carbon feedback in geospatial modeling frameworks

New trends in active faulting studies for seismic hazard assessment

Vulnerability to earthquakes increases steadily as urbanization and development expand in areas that are prone to the effects of significant earthquakes. As virtually all of the largest earthquakes of the past decade demonstrated, the development of large cities in high seismicity areas is often based on an insufficient knowledge or distorted perception of the local seismic hazard, a condition often worsened by the construction of seismically unsafe buildings and infrastructures

The catalytic subunit of the system L1 amino acid transporter (S<i>lc7a5</i>) facilitates nutrient signalling in mouse skeletal muscle

The System L1-type amino acid transporter mediates transport of large neutral amino acids (LNAA) in many mammalian cell-types. LNAA such as leucine are required for full activation of the mTOR-S6K signalling pathway promoting protein synthesis and cell growth. The SLC7A5 (LAT1) catalytic subunit of high-affinity System L1 functions as a glycoprotein-associated heterodimer with the multifunctional protein SLC3A2 (CD98). We generated a floxed Slc7a5 mouse strain which, when crossed with mice expressing Cre driven by a global promoter, produced Slc7a5 heterozygous knockout (Slc7a5+/-) animals with no overt phenotype, although homozygous global knockout of Slc7a5 was embryonically lethal. Muscle-specific (MCK Cre-mediated) Slc7a5 knockout (MS-Slc7a5-KO) mice were used to study the role of intracellular LNAA delivery by the SLC7A5 transporter for mTOR-S6K pathway activation in skeletal muscle. Activation of muscle mTOR-S6K (Thr389 phosphorylation) in vivo by intraperitoneal leucine injection was blunted in homozygous MS-Slc7a5-KO mice relative to wild-type animals. Dietary intake and growth rate were similar for MS-Slc7a5-KO mice and wild-type littermates fed for 10 weeks (to age 120 days) with diets containing 10%, 20% or 30% of protein. In MS-Slc7a5-KO mice, Leu and Ile concentrations in gastrocnemius muscle were reduced by ∼40% as dietary protein content was reduced from 30 to 10%. These changes were associated with >50% decrease in S6K Thr389 phosphorylation in muscles from MS-Slc7a5-KO mice, indicating reduced mTOR-S6K pathway activation, despite no significant differences in lean tissue mass between groups on the same diet. MS-Slc7a5-KO mice on 30% protein diet exhibited mild insulin resistance (e.g. reduced glucose clearance, larger gonadal adipose depots) relative to control animals. Thus, SLC7A5 modulates LNAA-dependent muscle mTOR-S6K signalling in mice, although it appears non-essential (or is sufficiently compensated by e.g. SLC7A8 (LAT2)) for maintenance of normal muscle mass

Phagocyte-derived catecholamines enhance acute inflammatory injury

It is becoming increasingly clear that the autonomic nervous system and the immune system demonstrate cross-talk during inflammation by means of sympathetic and parasympathetic pathways(1,2). We investigated whether phagocytes are capable of de novo production of catecholamines, suggesting an autocrine/paracrine self-regulatory mechanism by catecholamines during inflammation, as has been described for lymphocytes(3). Here we show that exposure of phagocytes to lipopolysaccharide led to a release of catecholamines and an induction of catecholamine-generating and degrading enzymes, indicating the presence of the complete intracellular machinery for the generation, release and inactivation of catecholamines. To assess the importance of these findings in vivo, we chose two models of acute lung injury. Blockade of alpha(2)-adrenoreceptors or catecholamine-generating enzymes greatly suppressed lung inflammation, whereas the opposite was the case either for an alpha(2)-adrenoreceptor agonist or for inhibition of catecholamine-degrading enzymes. We were able to exclude T cells or sympathetic nerve endings as sources of the injury-modulating catecholamines. Our studies identify phagocytes as a new source of catecholamines, which enhance the inflammatory response.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62733/1/nature06185.pd

Protection of innate immunity by C5aR antagonist in septic mice

Innate immune functions are known to be compromised during sepsis, often with lethal consequences. There is also evidence in rats that sepsis is associated with excessive complement activation and generation of the potent anaphylatoxin C5a. In the presence of a cyclic peptide antagonist (C5aRa) to the C5a receptor (C5aR), the binding of murine 125Iâ C5a to murine neutrophils was reduced, the in vitro chemotactic responses of mouse neutrophils to mouse C5a were markedly diminished, the acquired defect in hydrogen peroxide (H2O2) production of C5aâ exposed neutrophils was reversed, and the lung permeability index (extravascular leakage of albumin) in mice after intrapulmonary deposition of IgG immune complexes was markedly diminished. Mice that developed sepsis after cecal ligation/puncture (CLP) and were treated with C5aRa had greatly improved survival rates. These data suggest that C5aRa interferes with neutrophil responses to C5a, preventing C5aâ induced compromise of innate immunity during sepsis, with greatly improved survival rates after CLP.â Huberâ Lang, M. S., Riedeman, N. C., Sarma, J. V., Younkin, E. M., McGuire, S. R., Laudes, I. J., Lu, K. T., Guo, R.â F., Neff, T. A., Padgaonkar, V. A., Lambris, J. D., Spruce, L., Mastellos, D., Zetoune, F. S., Ward, P. A. Protection of innate immunity by C5aR antagonist in septic mice. FASEB J. 16, 1567â 1574 (2002)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154360/1/fsb2fj020209com.pd