scholarly journals Increased wave action promotes muscle performance but increasing temperatures cause a tenacity–endurance trade-off in intertidal snails (Nerita atramentosa)

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Samuel Clayman ◽  
Frank Seebacher
Keyword(s):  
Maximum Stress ◽  
Citrate Synthase ◽  
Wave Action ◽  
Sea Surface ◽  
Muscle Performance ◽  
Trade Off ◽  
Physiological Capacity ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
Physical Impact

Abstract Concurrent increases in wave action and sea surface temperatures increase the physical impact on intertidal organisms and affect their physiological capacity to respond to that impact. Our aim was to determine whether wave exposure altered muscle function in intertidal snails (Nerita atramentosa) and whether responses to wave action and temperature are plastic, leading to compensation for altered environmental conditions. We show that field snails from exposed shores had greater endurance and vertical tenacity than snails from matched protected shores (n = 5 pairs of shores). There were no differences in muscle metabolic capacities (strombine/lactate dehydrogenase, citrate synthase and cytochrome c oxidase activities) between shore types. Maximum stress (force/foot area) produced by isolated foot muscle did not differ between shore types, but foot muscle from snails on exposed shores had greater endurance. A laboratory experiment showed that vertical tenacity was greater in animals acclimated for 3 weeks to cool winter temperatures (15 C) compared to summer temperatures (25 C), but endurance was greater in snails acclimated to 25°C. Acclimation to water flow that mimicked wave action in the field increased vertical tenacity but decreased endurance. Our data show that increased wave action elicits a training effect on muscle, but that increasing sea surface temperature can cause a trade-off between tenacity and endurance. Ocean warming would negate the beneficial increase in tenacity that could render snails more resistant to acute impacts of wave action, while promoting longer term resistance to dislodgment by waves.

scholarly journals Intermittent pneumatic leg compressions enhance muscle performance and blood flow in a model of peripheral arterial insufficiency

2012 ◽  
Vol 112 (9) ◽  
pp. 1556-1563 ◽  
Author(s):  
Bruno T. Roseguini ◽  
Arturo A. Arce-Esquivel ◽  
Sean C. Newcomer ◽  
Hsiao T. Yang ◽  
Ronald Terjung ◽  
...  
Keyword(s):  
Blood Flow ◽  
Exercise Tolerance ◽  
Citrate Synthase ◽  
Arterial Disease ◽  
Muscle Performance ◽  
Sprague Dawley ◽  
Arterial Insufficiency ◽  
Mechanistic Basis ◽  
Peripheral Arterial

Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this therapy, remain poorly defined. We tested the hypothesis that 2 wk of daily application of IPC enhances exercise tolerance by improving blood flow and promoting angiogenesis in skeletal muscle in a model of peripheral arterial insufficiency. Male Sprague-Dawley rats were subjected to bilateral ligation of the femoral artery and randomly allocated to treatment or sham groups. Animals were anesthetized daily and exposed to 1-h sessions of bilateral IPC or sham treatment for 14–16 consecutive days. A third group of nonligated rats was also studied. Marked increases in treadmill exercise tolerance (∼33%, P < 0.05) and improved muscle performance in situ (∼10%, P < 0.05) were observed in IPC-treated animals. Compared with sham-treated controls, blood flow measured with isotope-labeled microspheres during in situ contractions tended to be higher in IPC-treated animals in muscles composed of predominantly fast-twitch white fibers, such as the plantaris (∼93%, P = 0.02). Capillary contacts per fiber and citrate synthase activity were not significantly altered by IPC treatment. Collectively, these data indicate that IPC improves exercise tolerance in a model of peripheral arterial insufficiency in part by enhancing blood flow to collateral-dependent tissues.

THE EFFECTS OF TEMPERATURE ON THE OXYGEN CONSUMPTION, HEART RATE AND DEEP BODY TEMPERATURE DURING DIVING IN THE TUFTED DUCK AYTHYA FULIGULA

1992 ◽  
Vol 163 (1) ◽  
pp. 139-151 ◽  
Author(s):  
R. M. BEVAN ◽  
P. J. BUTLER
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Deep Body Temperature ◽  
Tufted Duck ◽  
Winter Conditions ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
The Mean ◽  
Maintain Body Temperature ◽  
Deep Body

Six tufted ducks were trained to dive for food at summer temperatures (air, 26°C, water, 23°C) and at winter temperatures (air, 5.8°C, water 7.4°C). The mean resting oxygen consumption (Voo2) a t winter temperatures (rwin) was 90% higher than that at summer temperatures (Tsum), but deep body temperatures (Tb) were not significantly different. Diving behaviour and mean oxygen consumption for dives of mean duration were similar at Twin and at Tsum, although the mean oxygen consumption for surface intervals of mean duration was 50% greater at Twin and Tb was significantly lower (1°C) at the end of a series of dives in winter than it was in summer. There appears to be an energy saving of 67 J per dive during winter conditions and this may, at least partially, be the result of the metabolic heat produced by the active muscles being used to maintain body temperature. While at rest under winter conditions, this would be achieved by shivering thermogenesis. Thus, the energetic costs of foraging in tufted ducks in winter are not as great as might be expected from the almost doubling of metabolic rate in resting birds.

Cores and Peripheries Revisited: The Mining Landscapes of Wadi Faynan (Southern Jordan) 5000 BC–AD 700

2007 ◽  
Author(s):  
Graeme Barker ◽  
David Mattingly
Keyword(s):  
Roman Empire ◽  
Iron Age ◽  
Summer Temperature ◽  
Research Interest ◽  
Annual Rainfall ◽  
Winter Temperatures ◽  
Mountain Front ◽  
Summer Temperatures ◽  
The Mean ◽  
Landscape Survey

One of Barry Cunliffe’s major areas of research interest has been societies in transition, especially in the context of core/periphery relationships between expanding states and societies on their margins. Much of this work has been on the relationships between Rome and the Iron Age societies of southern Britain on the northwestern margins of the empire, and the subsequent pathways of resistance, interaction, and transformation. In this chapter we focus on events and processes on the opposite margins of the Roman empire in the Levant, where the Nabataean state was formally incorporated into the Roman imperial system some sixty years after the Claudian invasion of Britain. We draw on the results of the Wadi Faynan Landscape Survey (1996–2000), an interdisciplinary and diachronic investigation of evidence of environmental and climatic change, settlement pattern, and human activity in the Wadi Faynan in southern Jordan (figure 7.1). Situated about 40 kilometres from the Nabataean capital of Petra, the Wadi Faynan lies in the hot and hyper-arid Jordanian Desert, at a distinctive and spectacular mountain front that reaches 1500m above the desert floor. This landform marks the eastern margin of the desert lowlands of the great Jordanian rift valley, with the trough of the Wadi ‘Arabah to the south and west, and the highlands of the Mountains of Edom and the Jordanian tablelands to the east and north (Bienkowski and Galor 2006). The mean summer temperature on the Jordanian tablelands is in the order of 178c, compared with winter temperatures of about 12ºc (Bruins 2006; Rabb’a 1994). Winter temperatures on the desert floor in the Wadi Faynan are much the same as on the plateau, but in summer temperatures frequently reach 40ºc. Seasonality is strong, with most rain falling between December and March and virtually no precipitation occurring between June and September. Annual rainfall in the lower Wadi Faynan is around 63mm and even less in theWadi ‘Arabah (‘Aqaba receives 30mm for example), whereas the Jordanian Tablelands have an average precipitation exceeding 200mm per year.

Muscle adaptations in trained rats with peripheral arterial insufficiency

1991 ◽  
Vol 260 (2) ◽  
pp. H445-H452 ◽  
Author(s):  
T. P. Erney ◽  
G. M. Mathien ◽  
R. L. Terjung
Keyword(s):  
Citrate Synthase ◽  
Muscle Performance ◽  
O2 Consumption ◽  
Trained Group ◽  
Blood Flows ◽  
Training Adaptations ◽  
Muscle Adaptations ◽  
O2 Extraction ◽  
Arterial Insufficiency ◽  
Peripheral Arterial

The influence of training adaptations, induced within the active muscles of rats with peripheral arterial insufficiency, was assessed with an isolated hindlimb preparation. Femoral artery-stenosed rats, showing symptoms of intermittent claudication, were trained for 14-20 wk by running at 20-35 m/min up a 15% grade for up to approximately 1 h/day, 5 days/wk. Similar total hindlimb blood flows (12.6 ml/min) at a similar arterial O2 content (20.7 vol/100 ml) yielded similar blood flows (95-117 ml.min-1.100 g-1) and O2 deliveries (9-11 mumol.min-1.g-1) to the contracting muscle of sedentary (n = 10) and trained (n = 10) rats. Ten-minute periods of tetanic contractions (100 ms at 100 Hz each) at 4, 8, 13, 45, 60, and 90 tetani/min were used. Muscle force development was better maintained (P less than 0.001) by the trained group. Higher peak O2 consumption (P less than 0.01) of the trained (5.69 +/- 0.53 mumol.min-1.g-1) compared with the sedentary group (3.66 +/- 0.26 mumol.min-1.g-1) involved a greater O2 extraction, since delivery of O2 was not different between groups. Thus adaptations occurred within trained muscle to enhance performance and peak O2 consumption. Muscle citrate synthase activity, an index of mitochondrial content, was greater (P less than 0.005) in the trained group, with the low-oxidative white muscle section exhibiting the greatest change (approximately threefold sedentary). Adaptations in this section were probably realized functionally, since improvements in muscle performance were evident early in the contraction sequence.(ABSTRACT TRUNCATED AT 250 WORDS)

Population Dynamics and Food Habits of Bluegill (Lepomis macrochirus) in a Thermally Stressed Reservoir

1991 ◽  
Vol 48 (5) ◽  
pp. 768-775 ◽  
Author(s):  
Barbara E. Taylor ◽  
John M. Aho ◽  
Diane L. Mahoney ◽  
Ruth A. Estes
Keyword(s):  
South Carolina ◽  
Breeding Season ◽  
Nuclear Reactor ◽  
Lepomis Macrochirus ◽  
Thermal Conditions ◽  
Savannah River ◽  
Cooling Reservoir ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
River Site

Bluegill (Lepomis macrochirus) is the dominant fish species in a 67-ha cooling reservoir for a nuclear reactor on the Savannah River Site in South Carolina. Mortality and breeding season of bluegill were strongly influenced by reactor operations, which often produced temperatures of 40–60 °C in portions of the reservoir. Late spring and summer reactor operations caused ~ 90% mortality of bluegill. This mortality was largely associated with reactor restarts. Survivors occupied small thermal refuges in coves. Elevated fall and winter temperatures allowed an extended breeding season, although extremely high summer temperatures appeared to inhibit breeding. Bluegill depended primarily on benthic food resources, including dipterans and microcrustaceans. Despite the great variation in environmental conditions and diets, body condition of surviving bluegill was nearly constant between April 1985 and January 1986. Factors that contribute to the success of bluegill in this system include high thermal tolerance, broad diets, and an ability to breed when thermal conditions are appropriate, regardless of season.

Environment and Floristics of Ten Australian Alpine Vegetation Formations

1999 ◽  
Vol 47 (1) ◽  
pp. 1 ◽  
Author(s):  
J. B. Kirkpatrick ◽  
K. L. Bridle
Keyword(s):  
Environmental Variables ◽  
Geographic Range ◽  
Previous Literature ◽  
Alpine Vegetation ◽  
Environmental Relationships ◽  
Alpine Zone ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
Extractable Phosphorus

Data on floristics, structure and environment were collected from quadrats throughout the geographic range of alpine vegetation in Australia. These data were used to explore the floristic and environmental relationships of ten alpine vegetation formations: bolster heath, coniferous heath, heath, alpine sedgeland, fjaeldmark, tall alpine herbfield, short alpine herbfield, grassland, bog and fen. Alpine sedgeland and coniferous heath, and tall alpine herbfield and grassland, proved to be closely similar in their floristics. Grassland and coniferous heath were most separated in ordination space. The environmental variables with the largest numbers of significant differences between formations were extractable phosphorus, summer temperatures, winter temperatures and topography. However, many other edaphic, climatic, topographic and biotic variables were important in discriminating between formations. The results of the formation-environment analyses were largely consistent with the relationships suggested in the previous literature. However, some environmental differences between formations that were observed or posited from local studies did not prove to be exportable to the alpine zone as a whole. Edaphic and topographic variables appear to be more important in discriminating the environments of alpine formations than the environments of alpine floristic communities.

scholarly journals Food ingestion and assimilation by Hyale media (Dana, 1853) (Crustacea - Amphipoda)

1990 ◽  
Vol 38 (1) ◽  
pp. 11-21 ◽  
Author(s):  
Airton Santo Tararam ◽  
Hilda de Souza Lima Mesquita ◽  
Yoko Wakabara ◽  
Clóvis A Peres
Keyword(s):  
Developmental Stages ◽  
Specific Growth ◽  
Assimilation Efficiency ◽  
Effect Of Temperature ◽  
Adult Males ◽  
Food Ingestion ◽  
Young Males ◽  
Physiological Conditions ◽  
Winter Temperatures ◽  
Summer Temperatures

The feeding of Hyale media was analysed under laboratory conditions in winter and summer temperatures. The results showed that assimilation rates increased following food ingestion rates and decreased when egestion rates increased. In winter temperatures no significant differences were found in the assimilation rates among developmental stages and sexes. In summer temperatures assimilation rates for ovigerous and non-ovigerous females were higher than those found for adult and young males. Although not statistically analysed, mean assimilation efficiencies were highest among ovigerous females and adult males, in summer. The quantitative and qualitative variations found in the assimilation efficiency and rates were explained by the differential effect of temperature on the specific growth rate and in the physiological conditions of each growth stage concerned.

Impact of reduced cytochrome oxidase activity on peak oxygen consumption of muscle

1990 ◽  
Vol 69 (1) ◽  
pp. 384-389 ◽  
Author(s):  
R. M. McAllister ◽  
R. W. Ogilvie ◽  
R. L. Terjung
Keyword(s):  
Oxygen Consumption ◽  
Electron Transport ◽  
Cytochrome Oxidase ◽  
Citrate Synthase ◽  
Fiber Type ◽  
High Oxygen ◽  
Muscle Performance ◽  
Peak Oxygen Consumption ◽  
And Control ◽  
The Impact

The impact of reduced muscle oxidative capacity on peak oxygen consumption and isometric performance was evaluated using an isolated rat hindlimb preparation perfused with a high oxygen delivery. Capacity for electron transport was reduced with chloramphenicol (CAP), an inhibitor of mitochondrial gene-coded protein synthesis. The activity of cytochrome oxidase, a mitochondrial cristae component, was reduced approximately 45% (P less than 0.005) in the mixed-fiber-type plantaris muscle. Several facets of muscle remodeling were also evident with the 10- to 14-day CAP treatment, including decreased citrate synthase activity, increased capillarity, and increased numbers of type IIc fibers. Perfusion of CAP (n = 6) and control (n = 7) rat hindlimbs of similar size with similar total flows (10-11 ml/min) and oxygen contents (20-21 vol%) resulted in similarly high oxygen deliveries to contracting muscles of the hindlimbs (CAP, 9.66 +/- 0.83 mumols.min-1.g-1; control, 8.74 +/- 0.75). Performance of the gastrocnemius-plantaris-soleus group declined in a similar fashion for both groups during increasingly intense near-steady-state tetanic contraction (100 ms at 100 Hz) conditions of 4, 8, 15, 30, 45, and 60 per minute. Oxygen consumption was similar for both groups at rest and increased similarly at each contraction condition. Peak oxygen consumption was not different between CAP (5.34 +/- 0.55 mumols.min-1.g-1) and control (5.74 +/- 0.43) groups and required only 56-68% of the oxygen delivered. This implies that rat skeletal muscle can suffer a significant reduction in its electron transport capacity without impairing peak oxygen consumption and muscle performance.(ABSTRACT TRUNCATED AT 250 WORDS)

Geochemical and Geophysical Constraints on Life’s Origin

2019 ◽  
Author(s):  
David W. Deamer
Keyword(s):  
Origin Of Life ◽  
Liquid Water ◽  
Global Scale ◽  
Global Temperature ◽  
Death Valley ◽  
Winter Temperatures ◽  
Summer Temperatures ◽  
The Origin Of Life ◽  
Continuous Chemical ◽  
Hydrothermal Fields

Bernal's quote is a bit wordy, but he was basically saying that life can be understood as a continuous chemical reaction, and I agree. Throughout this book I will be describing ideas about how life can begin on habitable planets, which are defined as planets with orbits not too close and not too far from a star so that the temperature permits liquid water to exist. The conditions in which life can begin must have sufficient complexity to permit primitive life to assemble from organic chemicals dispersed in a sterile environment which then begin to react and evolve into more complex structures. This chapter will describe the main parameters of geochemical and geophysical complexity, and then consider them in terms of scales from the nanoscopic to the macroscopic. Questions to be addressed: What scales must be considered to understand how life can begin? What are the properties of the scales? How do the scales relate to the origin of life? The physical dimensions related to the origin of life can be described in terms of four scales—global, local, microscopic, and nanoscopic— and these dimensions must be related to the chemical and physical properties of each scale. The global scale is easiest to understand because the parameters are averages of very broad variables. For instance, we can state that the global temperature today is 15° C and even follow changes in the temperature to accuracies of a tenth of a degree on a year to year basis. However, within the global scale are extreme variations between winter temperatures of - 60° C at the poles and summer temperatures of 50° C in Death Valley, California. Of course, even higher temperatures are associated with hydrothermal fields, up to boiling at 100° C, but sometimes nearer to 90° C because the fields are usually at higher elevations associated with volcanoes. Table 2.1 summarizes the main parameters of the global scale on Earth and Mars today and compares their values with those near the time that life began on the Earth 4 billion years ago.

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