15 research outputs found
Breeding Birds of Mature Woodlands of Point Pelee National Park Prior to Infestation by Emerald Ash Borer, Agrilus planipennis
The Emerald Ash Borer (EAB) is a wood-boring beetle native to Asia that now infests and kills ash trees (Fraxinus spp.) in North America. Many ecological communities will be dramatically altered by the mortality of ash trees caused by this invasive insect. The EAB recently colonized Point Pelee National Park of Canada in extreme southwestern Ontario, Canada, a site famous for its unusual plant and animal diversity as well as its extraordinary bird migrations. We conducted a census of breeding birds in two ash-rich mature forests at Point Pelee in order to obtain baseline data on the breeding bird communities prior to changes in forest communities that are likely to be caused by the EAB. Here we report the results of the bird census and review possible changes to the breeding bird fauna of Point Pelee that may result from ash tree mortality and the associated disruption of forest communities
The relative influence of nutrients and habitat on stream metabolism in agricultural streams
Grip strength among community-dwelling older people predicts hospital admission during the following decade
Associations between objectively measured physical activity, body composition and sarcopenia: findings from the Hertfordshire Sarcopenia Study (HSS)
Regular physical activity (PA) is associated with reduced risk of the development and progression of musculoskeletal, metabolic and vascular disease. However, PA declines with age and this can contribute to multiple adverse outcomes. The aims of this study were to describe the relationship between accelerometer-determined PA, body composition and sarcopenia (the loss of muscle mass and function with age). Seven-day PA was measured using the GENEactiv accelerometer among 32 men and 99 women aged 74–84 years who participated in the Hertfordshire Sarcopenia Study. We measured mean daily acceleration and minutes/day spent in non-sedentary and moderate-to-vigorous physical activity (MVPA) levels. Body composition was measured by dual-energy X-ray absorptiometry, muscle strength by grip dynamometry and function by gait speed. Sarcopenia was defined according to the EWGSOP diagnostic algorithm. Men and women spent a median (inter-quartile range) of 138.8 (82, 217) and 186 (122, 240) minutes/day engaging in non-sedentary activity but only 14.3 (1.8, 30.2) and 9.5 (2.1, 18.6) min in MVPA, respectively. Higher levels of PA were associated with reduced adiposity, faster walking speed and decreased risk of sarcopenia. For example, a standard deviation (SD) increase in mean daily acceleration was associated with an increase in walking speed of 0.25 (95% CI 0.05, 0.45) SDs and a reduction in the risk of sarcopenia of 35% (95% CI 1, 57%) in fully adjusted analyses. PA was not associated with hand grip strength. Community-dwelling older adults in this study were largely sedentary but there was evidence that higher levels of activity were associated with reduced adiposity and improved function. PA at all intensity levels in later life may help maintain physical function and protect against sarcopenia
Mitochondrial respiratory chain deficiency in older men and its relationship with muscle mass and performance
Epigenome-wide association study of sarcopenia: findings from the Hertfordshire Sarcopenia Study (HSS)
Background: Sarcopenia is the age-related loss of muscle mass, strength, and function. Epigenetic processes such as DNA methylation, which integrate both genetic and environmental exposures, have been suggested to contribute to the development of sarcopenia. This study aimed to determine whether differences in the muscle methylome are associated with sarcopenia and its component measures: grip strength, appendicular lean mass index (ALMi), and gait speed.Methods: Using the Infinium Human MethylationEPIC BeadChip, we measured DNA methylation in vastus lateralis muscle biopsies of 83 male participants (12 with sarcopenia) with a mean (standard deviation) age of 75.7 (3.6) years from the Hertfordshire Sarcopenia Study (HSS) and Hertfordshire Sarcopenia Study extension (HSSe) and examined associations with sarcopenia and its components. Pathway, histone mark, and transcription factor enrichment of the differentially methylated CpGs (dmCpGs) were determined, and sodium bisulfite pyrosequencing was used to validate the sarcopenia-associated dmCpGs. Human primary myoblasts (n = 6) isolated from vastus lateralis muscle biopsies from male individuals from HSSe were treated with the EZH2 inhibitor GSK343 to assess how perturbations in epigenetic processes may impact myoblast differentiation and fusion, measured by PAX7 and MYHC immunocytochemistry, and mitochondrial bioenergetics determined using the Seahorse XF96.Results: Sarcopenia was associated with differential methylation at 176 dmCpGs (false discovery rate ≤ 0.05) and 141 differentially methylated regions (Stouffer ≤ 0.05). The sarcopenia-associated dmCpGs were enriched in genes associated with myotube fusion (P = 1.40E-03), oxidative phosphorylation (P = 2.78E-02), and voltage-gated calcium channels (P = 1.59E-04). ALMi was associated with 71 dmCpGs, grip strength with 49 dmCpGs, and gait speed with 23 dmCpGs (false discovery rate ≤ 0.05). There was significant overlap between the dmCpGs associated with sarcopenia and ALMi (P = 3.4E-35), sarcopenia and gait speed (P = 4.78E-03), and sarcopenia and grip strength (P = 7.55E-06). There was also an over-representation of the sarcopenia, ALMi, grip strength, and gait speed-associated dmCpGs with sites of H3K27 trimethylation (all P ≤ 0.05) and amongst EZH2 target genes (all P ≤ 0.05). Furthermore, treatment of human primary myoblasts with the EZH2 inhibitor GSK343 inhibitor led to an increase in PAX7 expression (P ≤ 0.05), decreased myotube fusion (P = 0.043), and an increase in ATP production (P = 0.008), with alterations in the DNA methylation of genes involved in oxidative phosphorylation and myogenesis.Conclusions: These findings show that differences in the muscle methylome are associated with sarcopenia and individual measures of muscle mass, strength, and function in older individuals. This suggests that changes in the epigenetic regulation of genes may contribute to impaired muscle function in later life
Implementing Performance-Based Sustainability Requirements for the Low Carbon Fuel Standard – Key Design Elements and Policy Considerations
California’s Low Carbon Fuel Standard (LCFS) adopted by the California Air Resources Board (CARB) on April 23, 2009 requires a 10% reduction in the average greenhouse gas (GHG) emission intensity of the state’s transportation fuels by 2020. This regulation is expected to reduce lifecycle GHG emissions per year by 20–25 million metric tons by 2020. Given available technology options, biofuels are expected to play a major role toward achieving the target. However, the rapid expansion of biofuel production may have environmental and social impacts at local, regional, and international levels. In response, many governments and national consortia have adopted sustainability requirements for their biofuel programs. The CARB is to propose a strategic plan for addressing overall sustainability provisions for the LCFS, for consideration by the Board for adoption by the end of 2011