Invasions and Extinctions as a Consequence of Climate Change

Invasions and extinctions are occurring at a rate that is unprecedented in historical time. These phenomena are a kind of biological extreme at each end of the spectrum, and both are responses related to landscape and environmental conditions, which also link to climate change. Research shows that species change their ranges in response to climate change and to general predictable trends, but individual responses seem to be idiosyncratic, said moderator Craig Allen. Because of this, there is a need to explicitly anticipate and think about ecological surprises and the unanticipated consequences of global change. Ecological systems often exhibit nonlinear threshold responses, so systems can change suddenly in response to a slow force such as climate change. The Platte River Basin can provide a focal point for the study of invasion and extinction and other effects on species related to changes in climate. The Platte River provides critical habitat for many species, including four threatened and endangered wildlife species: the least tern, piping plover, whooping crane and pallid sturgeon. The shallow riverine wetlands along a narrow 100-mile stretch of the central Platte River provide a crucial stop-over for whooping cranes and more than 500,000 sandhill cranes each spring during their northward migration. Approximately 300,000 shorebirds comprising more than 30 species migrate through the North American Migratory Flyway that transects Nebraska. At the other biological extreme, low water levels in the Platte induced by drought have led to invasive species problems. For example, the common reed Phragmites australis is choking the river channels and hindering habitat restoration efforts

Invasions and Extinctions as a Consequence of Climate Change

Invasions and extinctions are occurring at a rate that is unprecedented in historical time. These phenomena are a kind of biological extreme at each end of the spectrum, and both are responses related to landscape and environmental conditions, which also link to climate change. Research shows that species change their ranges in response to climate change and to general predictable trends, but individual responses seem to be idiosyncratic, said moderator Craig Allen. Because of this, there is a need to explicitly anticipate and think about ecological surprises and the unanticipated consequences of global change. Ecological systems often exhibit nonlinear threshold responses, so systems can change suddenly in response to a slow force such as climate change. The Platte River Basin can provide a focal point for the study of invasion and extinction and other effects on species related to changes in climate. The Platte River provides critical habitat for many species, including four threatened and endangered wildlife species: the least tern, piping plover, whooping crane and pallid sturgeon. The shallow riverine wetlands along a narrow 100-mile stretch of the central Platte River provide a crucial stop-over for whooping cranes and more than 500,000 sandhill cranes each spring during their northward migration. Approximately 300,000 shorebirds comprising more than 30 species migrate through the North American Migratory Flyway that transects Nebraska. At the other biological extreme, low water levels in the Platte induced by drought have led to invasive species problems. For example, the common reed Phragmites australis is choking the river channels and hindering habitat restoration efforts

Onset of experimental severe cardiac fibrosis is mediated by overexpression of angiotensin-converting enzyme 2

Angiotensin-converting enzyme (ACE) 2 is a recently identified homologue of ACE. There is great interest in the therapeutic benefit for ACE2 overexpression in the heart. However, the role of ACE2 in the regulation of cardiac structure and function, as well as maintenance of systemic blood pressure, remains poorly understood. In cell culture, ACE2 overexpression led to markedly increased myocyte volume, assessed in primary rabbit myocytes. To assess ACE2 function in vivo, we used a recombinant adeno-associated virus 6 delivery system to provide 11-week overexpression of ACE2 in the myocardium of stroke-prone spontaneously hypertensive rats. ACE2, as well as the ACE inhibitor enalapril, significantly reduced systolic blood pressure. However, in the heart, ACE2 overexpression resulted in cardiac fibrosis, as assessed by histological analysis with concomitant deficits in ejection fraction and fractional shortening measured by echocardiography. Furthermore, global gene expression profiling demonstrated the activation of profibrotic pathways in the heart mediated by ACE2 gene delivery. This study demonstrates that sustained overexpression of ACE2 in the heart in vivo leads to the onset of severe fibrosis

Effect of dietary nitrate supplementation on conduit artery blood flow, muscle oxygenation, and metabolic rate during handgrip exercise

Dietary nitrate supplementation has positive effects on mitochondrial and muscle contractile efficiency during large muscle mass exercise in humans and on skeletal muscle blood flow (Q̇) in rats. However, concurrent measurement of these effects has not been performed in humans. Therefore, we assessed the influence of nitrate supplementation on Q̇ and muscle oxygenation characteristics during moderate- (40 %peak) and severe-intensity(85% peak) handgrip exercise in a randomized, double-blind, crossover design. Nine healthy men (age: 25 ± 2 yr) completed four constant-power exercise tests (2/intensity) randomly assigned to condition [nitrate-rich (nitrate) or nitrate-poor (placebo) beetroot supplementation] and intensity (40 or 85% peak). Resting mean arterial pressure was lower after nitrate compared with placebo (84 ± 4 vs. 89 ± 4 mmHg, P &lt; 0.01). All subjects were able to sustain 10 min of exercise at 40% peak in both conditions. Nitrate had no effect on exercise tolerance during 85% peak (nitrate: 358 ± 29; placebo: 341 ± 34 s; P = 0.3). Brachial artery Q̇ was not different after nitrate at rest or any time during exercise. Deoxygenated [hemoglobin + myoglobin] was not different for 40% peak ( P &gt; 0.05) but was elevated throughout 85% peak ( P &lt; 0.05) after nitrate. The metabolic cost (V̇o2) was not different at the end of exercise; however, the V̇o2 primary amplitude at the onset of exercise was elevated after nitrate for the 85% peak work rate (96 ± 20 vs. 72 ± 12 ml/min, P &lt; 0.05) and had a faster response. These findings suggest that an acute dose of nitrate reduces resting blood pressure and speeds V̇o2 kinetics in young adults but does not augment Q̇ or reduce steady-state V̇o2 during small muscle mass handgrip exercise. NEW &amp; NOTEWORTHY We show that acute dietary nitrate supplementation via beetroot juice increases the amplitude and speed of local muscle V̇o2 on kinetics parameters during severe- but not moderate-intensity handgrip exercise. These changes were found in the absence of an increased blood flow response, suggesting that the increased V̇o2 was attained via improvements in fractional O2 extraction and/or spatial distribution of blood flow within the exercising muscle. </jats:p

Correlates of children's independent outdoor play: Cross-sectional analyses from the Millennium Cohort Study

Time spent outdoors is associated with higher levels of physical activity. To date, correlates of independent outdoor play have not been investigated. This study aimed to identify potential demographic, behavioural, environmental and social correlates of children's independent outdoor play. Data were from the Millennium Cohort Study when children were aged 7 years. Parents reported whether their children played out unsupervised (yes/no) as well as the above mentioned correlates of unsupervised outdoor play. Children's physical activity levels were measured using waist worn accelerometry. Multiple logistic regression was used to examine associations between correlates and odds of independent (unsupervised) outdoor play. Adjusted multiple linear regression was used to estimate associations between independent outdoor play and objective measures of physical activity. Activity was measured as average daily moderate-to-vigorous activity, steps, and sedentary behaviour. 3856 (n = 29%) participants were categorised as engaging in independent outdoor play. Older age, being white British, being in poverty, living in close proximity to both family friends and family, having fewer internalising problems, having more externalising conduct problems and fewer pro-social behaviours were associated with higher odds of independent outdoor play. Independent outdoor play was associated with > 2 additional minutes of moderate-to-vigorous activity (B = 2.21 95% CI, 1.09 to 3.34), > 330 additional steps per day (B = 336.66 95% CI 209.80 to 463.51), and nearly 5 min less time spent sedentary per day (B = − 4.91 95% CI − 7.54, − 2.29) Younger children, those from a higher socio-economic-status, those isolated in location from family friends and family, and those with high levels of prosocial behaviour have lower levels of independent outdoor play. Independent outdoor play was associated with higher levels of physical activity and less time sedentary. Future interventions to promote independent outdoor play should target such populations

Effect of Acute High-intensity Interval Exercise on Whole-body Fat Oxidation and Subcutaneous Adipose Tissue Cell Signaling in Overweight Women

International Journal of Exercise Science 13(2): 554-566, 2020. Exercise-induced alterations in adipose tissue insulin and/or β-adrenergic signaling may contribute to increases in whole-body fat oxidation following acute exercise. Thus, we examined changes in insulin (Akt, AS160) and β-adrenergic (PKA) signaling proteins in subcutaneous adipose tissue and whole-body fat oxidation in overweight women following acute high-intensity interval exercise (HIIE). Overweight females completed two experimental sessions in a randomized order: 1) control (bed rest) and 2) HIIE (10 x 4 min running intervals at 90% HRmax, 2-min recovery). Subcutaneous abdominal adipose tissue biopsies were obtained from 10 participants before (pre-), immediately (0hr) after (post-), 2hr post-, and 4hr post-exercise. Plasma glucose and insulin levels were assessed in venous blood samples obtained at each biopsy time-point from a different group of 5 participants (BMI-matched to biopsy group). Fat oxidation rates were estimated using the respiratory exchange ratio (RER) in all participants using indirect calorimetry pre-, 2hr post-, and 4hr post-exercise. RER was decreased (p \u3c 0.05) at 2hr post-exercise after HIIE (0.77 ± 0.04) compared to control (0.84 ± 0.04). Despite higher plasma glucose (p \u3c 0.01) and insulin (p \u3c 0.05) levels at 0hr post-exercise versus control, no significant interaction effects were observed for Akt or AS160 phosphorylation (p \u3e 0.05). Phosphorylation of PKA substrates was unaltered in both conditions (p \u3e 0.05). Collectively, altered β-adrenergic and insulin signaling in subcutaneous adnominal adipose tissue does not appear to explain increased whole-body fat oxidation following acute HIIE

Designer diatom episomes delivered by bacterial conjugation.

Eukaryotic microalgae hold great promise for the bioproduction of fuels and higher value chemicals. However, compared with model genetic organisms such as Escherichia coli and Saccharomyces cerevisiae, characterization of the complex biology and biochemistry of algae and strain improvement has been hampered by the inefficient genetic tools. To date, many algal species are transformable only via particle bombardment, and the introduced DNA is integrated randomly into the nuclear genome. Here we describe the first nuclear episomal vector for diatoms and a plasmid delivery method via conjugation from Escherichia coli to the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. We identify a yeast-derived sequence that enables stable episome replication in these diatoms even in the absence of antibiotic selection and show that episomes are maintained as closed circles at copy number equivalent to native chromosomes. This highly efficient genetic system facilitates high-throughput functional characterization of algal genes and accelerates molecular phytoplankton research

A Study of the Feasibility and Potential Implementation of Metro-Based Freight Transportation in Newcastle upon Tyne

The concept of using a metropolitan railway network to transport freight directly to a city centre from the surrounding businesses has been the subject of much research. This paper looks in depth at the Tyne and Wear Metro system, situated in Newcastle upon Tyne, to determine if such a scheme would be feasible. Through research into the modes of transport available, along with a review of literature and case studies, it was found that the current method of transporting the majority of freight by road is unsustainable and damaging to both the environment and local communities. Other options for the transportation of freight have been reviewed, and results showed that a modal shift will be necessary in the near future. The system was then modelled using software provided by the Department for Transport, which demonstrated that the implementation of such a scheme would provide vast accident savings, a reduction in the number of casualties on the road, and a monetary saving as a result of the lower casualty rate. The conclusion was reached that the scheme is viable, however further research and study is necessary before implementation

Morphological and dietary responses of chipmunks to a century of climate change.

Predicting how individual taxa will respond to climatic change is challenging, in part because the impacts of environmental conditions can vary markedly, even among closely related species. Studies of chipmunks (Tamias spp.) in Yosemite National Park provide an important opportunity to explore the reasons for this variation in response. While the alpine chipmunk (T.&nbsp;alpinus) has undergone a significant elevational range contraction over the past century, the congeneric and partially sympatric lodgepole chipmunk (T.&nbsp;speciosus) has not experienced an elevational range shift during this period. As a first step toward identifying the factors underlying this difference in response, we examined evidence for dietary changes and changes in cranial morphology in these species over the past century. Stable isotope analyses of fur samples from modern and historical museum specimens of these species collected at the same localities indicated that signatures of dietary change were more pronounced in T.&nbsp;alpinus, although diet breadth did not differ consistently between the study species. Morphometric analyses of crania from these specimens revealed significant changes in cranial shape for T.&nbsp;alpinus, with less pronounced changes in shape for T.&nbsp;speciosus; evidence of selection on skull morphology was detected for T.&nbsp;alpinus, but not for T.&nbsp;speciosus. These results are consistent with growing evidence that T.&nbsp;alpinus is generally more responsive to environmental change than T.&nbsp;speciosus, but emphasize the complex and often geographically variable nature of such responses. Accordingly, future studies that make use of the taxonomically and spatially integrative approach employed here may prove particularly informative regarding relationships between environmental conditions, range changes, and patterns of phenotypic variation