Short-term temperature effects on the anaerobic metabolism of glycogen accumulating organisms

2007 ◽  
Vol 97 (3) ◽  
pp. 483-495 ◽  
Author(s):  
Carlos M. Lopez-Vazquez ◽  
Young-Il Song ◽  
Christine M. Hooijmans ◽  
Damir Brdjanovic ◽  
Moustafa S. Moussa ◽  
...  
Keyword(s):  
Temperature Effects ◽  
Anaerobic Metabolism ◽  
Short Term

Na+-K+-ATPase activity in medullary thick ascending limb during short-term anoxia

1987 ◽  
Vol 252 (5) ◽  
pp. F838-F843 ◽  
Author(s):  
M. E. Chamberlin ◽  
L. J. Mandel
Keyword(s):  
Atpase Activity ◽  
Anaerobic Metabolism ◽  
Potassium Content ◽  
Simultaneous Increase ◽  
Extracellular Potassium ◽  
Thick Ascending Limb ◽  
Tight Coupling ◽  
Short Term ◽  
Medullary Thick Ascending Limb ◽  
Important Pathway

Na+-K+-ATPase activity was measured in a suspension of rabbit medullary thick ascending limb tubules under oxygenated and anoxic conditions. Oxygenated, K-depleted tubules rapidly take up added extracellular potassium accompanied by a simultaneous increase in oxygen consumption. The ATP/O2 ratio was 12.5 +/- 0.7, suggesting a tight coupling between oxidative metabolism (6 ATP/O2) and Na+-K+-ATPase activity (2 K/ATP). On reaching anoxia, the tubules released potassium into the medium, but this rate was accelerated by the addition of ouabain, which indicated that the Na+-K+-ATPase was still operative in anoxia. Because 10 min of anoxia led to only a 15.7% decline in potassium content, a new steady state of potassium uptake and leakage must be reached during anoxia. Anaerobic metabolism maintained 73% of cellular ATP during 10 min of anoxia. Exposure of anoxic tubules to iodoacetate produced a 57% decline in ATP levels and a 33% decline in potassium content, which indicated that glycolysis is an important pathway in supplying energy during anaerobiosis.

Anaerobic metabolism in goldfish (Carassius auratus)

1977 ◽  
Vol 55 (8) ◽  
pp. 1304-1311 ◽  
Author(s):  
R. M. Walker ◽  
P. H. Johansen
Keyword(s):  
Carassius Auratus ◽  
Glycogen Phosphorylase ◽  
Anaerobic Metabolism ◽  
Liver Glycogen ◽  
Energy Yield ◽  
Low Oxygen ◽  
Short Term ◽  
Liver Size ◽  
Goldfish Carassius Auratus ◽  
Glycogen Stores

At 20 °C goldfish survive anaerobic conditions for only a few hours while at 4 °C survival is extended to several days. During the course of low-temperature anaerobiosis there was a rise in blood glucose and lactate, a decline in liver glycogen concentration, and an increase in liver water content, while liver size remained constant.The better cold anaerobic survival of winter and hypophysectomized goldfish compared with spring and sham-operated animals was correlated with greater glycogen stores in the livers of the former. It is concluded that liver glycogen is a necessary energy source during cold anaerobiosis, and it is suggested that the resulting hyperglycemia may represent a mechanism to increase glycolytic energy yield. Cold anaerobiosis also resulted in elevated liver glucose-6-phosphatase (EC 3.1.3.9) activity, suggesting an increase in glycogenolysis, but no change in glycogen phosphorylase (EC 2.4.1.1) activity. While cold anaerobic survival is short term it is possible that liver glycogen may sustain goldfish for longer periods at low oxygen levels through a mixed aerobic–anaerobic metabolism.

Caffeine, performance, and metabolism during repeated Wingate exercise tests

1998 ◽  
Vol 85 (4) ◽  
pp. 1502-1508 ◽  
Author(s):  
F. Greer ◽  
C. McLean ◽  
T. E. Graham
Keyword(s):  
Power Output ◽  
High Intensity ◽  
Anaerobic Metabolism ◽  
Exercise Bout ◽  
High Intensity Exercise ◽  
Intense Exercise ◽  
Short Term ◽  
Exercise Tests ◽  
Negative Effect ◽  
Epinephrine Concentration

Investigations examining the ergogenic and metabolic influence of caffeine during short-term high-intensity exercise are few in number and have produced inconsistent results. This study examined the effects of caffeine on repeated bouts of high-intensity exercise in recreationally active men. Subjects ( n = 9) completed four 30-s Wingate (WG) sprints with 4 min of rest between each exercise bout on two separate occasions. One hour before exercise, either placebo (Pl; dextrose) or caffeine (Caf; 6 mg/kg) capsules were ingested. Caf ingestion did not have any effect on power output (peak or average) in the first two WG tests and had a negative effect in the latter two exercise bouts. Plasma epinephrine concentration was significantly increased 60 min after Caf ingestion compared with Pl; however, this treatment effect disappeared once exercise began. Caf ingestion had no significant effect on blood lactate, O2 consumption, or aerobic contribution at any time during the protocol. After the second Wingate test, plasma NH3concentration increased significantly from the previous WG test and was significantly higher in the Caf trial compared with Pl. These data demonstrate no ergogenic effect of caffeine on power output during repeated bouts of short-term, intense exercise. Furthermore, there was no indication of increased anaerobic metabolism after Caf ingestion with the exception of an increase in NH3 concentration.

Effects of short-term low temperature stress on chlorophyll fluorescence transients in Antarctic lichen species

2016 ◽  
Vol 6 (1) ◽  
pp. 54-65 ◽  
Author(s):  
Michaela Marečková ◽  
Miloš Barták
Keyword(s):  
Chlorophyll Fluorescence ◽  
Low Temperature ◽  
Temperature Effects ◽  
Photochemical Quenching ◽  
Short Term ◽  
Ps Ii ◽  
Species Specific ◽  
Non Photochemical Quenching ◽  
Fluorescence Transients ◽  
Chlorophyll Fluorescence Transients

Chlorophyll fluorescence is an effective tool for investigating characteristics of any photosynthesizing organisms and its responses due to different stressors. Here, we have studied a short-term temperature response on two Antarctic green algal lichen species: Umbilicaria antarctica, and Physconia muscigena. We measured slow chlorophyll fluorescence transients in the species during slow a cooling of thallus temperature from 20°C to 5°C with a 10 min. acclimation at each temperature in dark. The measurements were supplemented with saturation pulses for the analysis of chlorophyll fluorescence parameters: maximum yield of PS II photochemistry (FV/FM), effective quantum yield of PS II photochemistry (FPSII) and non-photochemical quenching (NPQ). In response to decreasing thallus temperature, we observed species-specific changes in chlorophyll fluorescence levels P, S, M, T reached during chlorophyll fluorescence transient as well as in the shape of the chlorophyll fluorescence transients. With a decrease in temperature, the time at which M and T chlorophyll fluorescence levels were reached, increased. These changes were attributed to redox state of plastoquinon pool, changes in Calvin-Benson cycle activity, non-photochemical quenching components, state transition in particular. In this study, we present some chlorophyll fluorescence ratios (P/M, M/T, P/T) and chlorophyll fluorescence increase rates (FR1, i.e. O to P, and FR2 - i.e. S to M) as the parameters reflecting direct temperature effects on chloroplastic apparatus of lichen alga sensitively. We proposed that species-specific changes in the slow phase of chlorophyll fluorescence transients could be potentially used as indicators of low temperature effects in photosynthetic apparatus of lichen algal photobionts. Interspecific differences in response to low temperature might be evaluated using the approach as well.

scholarly journals Experimental evidence for foraminiferal calcification under anoxia

2014 ◽  
Vol 11 (3) ◽  
pp. 4669-4694 ◽  
Author(s):  
M. P. Nardelli ◽  
C. Barras ◽  
E. Metzger ◽  
A. Mouret ◽  
H. L. Filipsson ◽  
...  
Keyword(s):  
Anaerobic Metabolism ◽  
Environmental Variability ◽  
Adult Mortality ◽  
Short Term ◽  
Essential Information ◽  
Ample Evidence ◽  
Anoxic Conditions ◽  
Inhibition Of Growth ◽  
Foraminiferal Species ◽  
First Time

Abstract. Benthic foraminiferal tests are widely used for paleoceanographic reconstructions. There is ample evidence that foraminifera can live in anoxic sediments. For some species, this is explained by a switch to facultative anaerobic metabolism (i.e. denitrification). Here we show for the first time that adult specimens of three benthic foraminiferal species are not only able to survive but are also able to calcify in anoxic conditions, at various depths in the sediment, with and without nitrates. This demonstrates ongoing metabolic processes, even in micro-environments where denitrification is not possible. Earlier observations suggest that the disappearance of foraminiferal communities after prolonged anoxia is not due to instantaneous or strongly increased adult mortality. Here we show that it cannot be explained by an inhibition of growth through chamber addition either. Our observations of ongoing calcification under anoxic conditions means that geochemical proxy data obtained from benthic foraminifera in settings experiencing intermittent anoxia have to be reconsidered. The analysis of whole single specimens or of their successive chambers may provide essential information about short-term environmental variability and/or the causes of anoxia.

scholarly journals Short-Term City Electric Load Forecasting with Considering Temperature Effects: An Improved ARIMAX Model

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Herui Cui ◽  
Xu Peng
Keyword(s):  
Temperature Effects ◽  
Load Forecasting ◽  
Sigmoid Function ◽  
Electric Load ◽  
Short Term ◽  
External Temperature ◽  
Ann Models ◽  
Electricity Load ◽  
Mutation Data ◽  
Improved Model

Short-term electric load is significantly affected by weather, especially the temperature effects in summer. External factors can result in mutation structures in load data. Under the influence of the external temperature factors, city electric load cannot be easily forecasted as usual. This research analyzes the relationship between electricity load and daily temperature in city. An improved ARIMAX model is proposed in this paper to deal with the mutation data structures. It is found that information amount of the improved ARIMAX model is smaller than that of the classic method and its relative error is less than AR, ARMA and Sigmoid-Function ANN models. The forecasting results are more accurately fitted. This improved model is highly valuable when dealing with mutation data structure in the field of load forecasting. And it is also an effective technique in forecasting electric load with temperature effects.

The challenge of predicting temperature effects on short-term predator–prey dynamics

2014 ◽  
Vol 56 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Karen C. Abbott ◽  
Jason P. Harmon ◽  
Nicholas S. Fabina
Keyword(s):  
Temperature Effects ◽  
Short Term ◽  
Predator Prey
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