scholarly journals Metabolic cost of freeze-thaw and source of CO2 production in the freeze-tolerant cricket Gryllus veletis

2020 ◽  
pp. jeb.234419
Author(s):  
Adam Smith ◽  
Kurtis F. Turnbull ◽  
Julian H. Moulton ◽  
Brent J. Sinclair
Keyword(s):  
Metabolic Rate ◽  
Metabolic Cost ◽  
Field Cricket ◽  
Co2 Production ◽  
System Response ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Metabolic Costs ◽  
Gryllus Veletis ◽  
Freeze Tolerant

Freeze-tolerant insects can survive the conversion of a substantial portion of their body water to ice. While the process of freezing induces active responses from some organisms, these responses appear absent from freeze-tolerant insects. Recovery from freezing likely requires energy expenditure to repair tissues and re-establish homeostasis, which should be evident as elevations in metabolic rate after thaw. We measured carbon dioxide (CO2) production in the spring field cricket (Gryllus veletis) as a proxy for metabolic rate during cooling, freezing and thawing and compared the metabolic costs associated with recovery from freezing and chilling. We hypothesized that freezing does not induce active responses, but that recovery from freeze-thaw is metabolically costly. We observed a burst of CO2 release at the onset of freezing in all crickets that froze, including those killed by either cyanide or an insecticide (thiacloprid), implying that the source of this CO2 was neither aerobic metabolism or a coordinated nervous system response. These results suggest that freezing does not induce active responses from G. veletis, but may liberate buffered CO2 from hemolymph. There was a transient ‘overshoot’ in CO2 release during the first hour of recovery, and elevated metabolic rates at 24, 48 and 72 hours, in crickets that had been frozen compared to crickets that had been chilled (but not frozen). Thus, recovery from freeze-thaw and the repair of freeze-induced damage appears metabolically costly in G. veletis, and this cost persists for several days after thawing.

scholarly journals Evidence for non-colligative function of small cryoprotectants in a freeze-tolerant insect

2019 ◽  
Vol 286 (1899) ◽  
pp. 20190050 ◽  
Author(s):  
Jantina Toxopeus ◽  
Vladimír Koštál ◽  
Brent J. Sinclair
Keyword(s):  
Fat Body ◽  
Ex Vivo ◽  
Freeze Tolerance ◽  
Field Cricket ◽  
Ice Formation ◽  
Low Molecular Weight ◽  
Manipulative Experiments ◽  
Gryllus Veletis ◽  
Freeze Tolerant

Freeze tolerance, the ability to survive internal ice formation, facilitates survival of some insects in cold habitats. Low-molecular-weight cryoprotectants such as sugars, polyols and amino acids are hypothesized to facilitate freeze tolerance, but their in vivo function is poorly understood. Here, we use a combination of metabolomics and manipulative experiments in vivo and ex vivo to examine the function of multiple cryoprotectants in the spring field cricket Gryllus veletis . Cold-acclimated G. veletis are freeze-tolerant and accumulate myo -inositol, proline and trehalose in their haemolymph and fat body. Injecting freeze-tolerant crickets with proline and trehalose increases survival of freezing to lower temperatures or for longer times. Similarly, exogenous myo -inositol and trehalose increase ex vivo freezing survival of fat body cells from freeze-tolerant crickets. No cryoprotectant (alone or in combination) is sufficient to confer freeze tolerance on non-acclimated, freeze-intolerant G. veletis . Given that each cryoprotectant differentially impacts survival in the frozen state, we conclude that small cryoprotectants are not interchangeable and likely function non-colligatively in insect freeze tolerance. Our study is the first to experimentally demonstrate the importance of non-colligative cryoprotectant function for insect freeze tolerance both in vivo and ex vivo , with implications for choosing new molecules for cryopreservation.

scholarly journals Balancing Selection on Electrophoretic Variation of Phosphoglucose Isomerase in Two Species of Field Cricket: Gryllus veletis and G. pennsylvanicus

Genetics ◽  
1997 ◽  
Vol 147 (2) ◽  
pp. 609-621
Author(s):  
Laura A Katz ◽  
Richard G Harrison
Keyword(s):  
Balancing Selection ◽  
Emergent Property ◽  
Phosphoglucose Isomerase ◽  
Field Cricket ◽  
Nucleotide Variation ◽  
Eastern United States ◽  
Electrophoretic Variation ◽  
Sympatric Populations ◽  
Field Crickets ◽  
Gryllus Veletis

Two species of crickets, Gryllus veletis and G. pennsylvanicus, share six electrophoretic mobility classes for the enzyme phosphoglucose isomerase (PGI), despite evidence from other genetic markers that the two species are not closely related within eastern North American field crickets. Moreover, the frequencies of the two most common PGI electrophoretic classes (PGI-100 and PGI-65) covary in sympatric populations of these species in the eastern United States, suggesting that PGI may be subject to trans-specific balancing selection. To determine the molecular basis of the electrophoretic variation, we characterized the DNA sequence of the Pgi gene from 29 crickets (15 G. veletis and 14 G. pennsylvanicus). Amino acid substitutions that distinguish the electrophoretic classes are not the same in the two species, and there is no evidence that specific replacement substitutions represent trans-specific polymorphism. In particular, the amino acids that diagnose the PGI-65 allele relative to the PGI-100 allele differ both between G. veletis and G. pennsylvanicus and within G. pennsylvanicus. The heterogeneity among electrophoretic classes that covary in sympatric populations coupled with analysis of patterns of nucleotide variation suggest that Pgi is not evolving neutrally. Instead, the data are consistent with balancing selection operating on an emergent property of the PGI protein.

scholarly journals Limitations of Foot-Worn Sensors for Assessing Running Power

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 4952
Author(s):  
Tobias Baumgartner ◽  
Steffen Held ◽  
Stefanie Klatt ◽  
Lars Donath
Keyword(s):  
Time Use ◽  
Stride Length ◽  
Metabolic Cost ◽  
Running Economy ◽  
Accelerometer Data ◽  
Gait Characteristics ◽  
Significant Difference ◽  
Metabolic Costs ◽  
Ground Contact Time ◽  
Training Signal

Running power as measured by foot-worn sensors is considered to be associated with the metabolic cost of running. In this study, we show that running economy needs to be taken into account when deriving metabolic cost from accelerometer data. We administered an experiment in which 32 experienced participants (age = 28 ± 7 years, weekly running distance = 51 ± 24 km) ran at a constant speed with modified spatiotemporal gait characteristics (stride length, ground contact time, use of arms). We recorded both their metabolic costs of transportation, as well as running power, as measured by a Stryd sensor. Purposely varying the running style impacts the running economy and leads to significant differences in the metabolic cost of running (p < 0.01). At the same time, the expected rise in running power does not follow this change, and there is a significant difference in the relation between metabolic cost and power (p < 0.001). These results stand in contrast to the previously reported link between metabolic and mechanical running characteristics estimated by foot-worn sensors. This casts doubt on the feasibility of measuring running power in the field, as well as using it as a training signal.

scholarly journals Strength and Microscopic Damage Mechanism of Yellow Sandstone with Holes under Freezing and Thawing

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Huren Rong ◽  
Jingyu Gu ◽  
Miren Rong ◽  
Hong Liu ◽  
Jiayao Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Size ◽  
Power Function ◽  
Damage Mechanism ◽  
Uniaxial Compression Test ◽  
Freezing And Thawing ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Microscopic Damage

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

Review of Strength and Failure Criteria for Concrete After Freeze-Thaw Damage

2012 ◽  
Vol 253-255 ◽  
pp. 456-461
Author(s):  
Yan Fu Qin ◽  
Bin Tian ◽  
Gang Xu ◽  
Xiao Chun Lu
Keyword(s):  
Normal State ◽  
Concrete Strength ◽  
Failure Criteria ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Normal Concrete ◽  
Strength Criteria ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Concrete Failure

Frost resistance research is one of the important subject of concrete durability, however strength criteria is an important part of the study of mechanical behavior of concrete. So far, about concrete failure criteria are almost for normal concrete, which the domestic and overseas scholars have comparative detailed research in every respect to it, and to freeze-thaw damage of concrete but few research. Based on the summary of the existing ordinary concrete strength and failure criteria in normal state and after freeze-thaw damage，this paper have a brief comment of failure criteria on concrete after freeze-thaw damage. For later research about concrete strength and failure criteria under freezing and thawing cycle provide the reference.

scholarly journals Supplementation of freezing and thawing media with brain-derived neurotrophic factor protects human sperm from freeze-thaw-induced damage

2016 ◽  
Vol 106 (7) ◽  
pp. 1658-1665.e4 ◽  
Author(s):  
Atefeh Najafi ◽  
Ebrahim Asadi ◽  
Adel R. Moawad ◽  
Saideh Mikaeili ◽  
Fardin Amidi ◽  
...  
Keyword(s):  
Neurotrophic Factor ◽  
Human Sperm ◽  
Brain Derived Neurotrophic Factor ◽  
Freezing And Thawing ◽  
Freeze Thaw

Measurements of metabolic rate in rats: a comparison of techniques

1988 ◽  
Vol 65 (2) ◽  
pp. 964-970 ◽  
Author(s):  
T. I. Musch ◽  
A. Bruno ◽  
G. E. Bradford ◽  
A. Vayonis ◽  
R. L. Moore
Keyword(s):  
Metabolic Rate ◽  
Maximal Exercise ◽  
Ambient Air ◽  
Open Circuit ◽  
Submaximal Exercise ◽  
Co2 Production ◽  
Arterial Blood ◽  
In Series ◽  
Series Of Experiments ◽  
Four Levels

Two different open-circuit techniques of measuring metabolic rate were examined in rats at rest and during exercise. With one technique ambient air was drawn through a tightly fitting mask that was secured to the rat's head, whereas with the other technique the rat was placed into and ambient air was drawn through a Plexiglas box. Two series of experiments were performed. In series I, two groups were studied that consisted of rats that had received myocardial infarctions produced by coronary arterial ligations and rats that had received sham operations. In this series of experiments O2 uptake (VO2) and CO2 production (VCO2) were measured at rest, during four levels of submaximal exercise, and during maximal treadmill exercise in the same group of rats by use of both techniques in random order. VO2, VCO2, and the calculated respiratory exchange ratio (R) were similar at rest, during the highest level of submaximal exercise (20% grade, 37 m/min), and during maximal exercise; however, VO2 and VCO2 were significantly lower with the metabolic box technique compared with the mask technique during the three lowest work loads (5% grade, 19 m/min; 10% grade, 24 m/min; and 15% grade, 31 m/min). These differences appeared to be associated with a change in gait produced when the mask was worn. In series II, the arterial blood gas and acid-base responses to both submaximal and maximal exercise were measured using both techniques in a group of instrumented rats that had a catheter placed into the right carotid artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Measurement of metabolic rate in hyperoxia

1981 ◽  
Vol 51 (3) ◽  
pp. 725-731 ◽  
Author(s):  
H. G. Welch ◽  
P. K. Pedersen
Keyword(s):  
Metabolic Rate ◽  
Submaximal Exercise ◽  
Co2 Production ◽  
O2 Uptake ◽  
Vo2 Max ◽  
Conventional Calculation ◽  
Mixing Chamber ◽  
Douglas Bag ◽  
Douglas Bag Method ◽  
Fick Equation

The conventional Douglas bag calculation for estimating O2 uptake (VO2) during exercise in normoxia and hyperoxia, VO2 = VE . (FIO2 . FEN2/FIN2 - FEO2), was tested against two other valid calculations: the Fick equation, VO2 = VI . FIO2 - VE . FEO2, and the equation VO2 = VI - VE - VCO2 (VE and VI are expired and inspired ventilation, respectively; FEO2 and FIO2 are expired and inspired O2 contents, respectively; FEN2 and FIN2 are expired and inspired N2 contents, respectively; and VCO2 is CO2 production.). These calculations are based on different assumptions, in part, and are affected to a varying degree of errors in volume or gas fraction measurements. With the conventional Douglas bag technique, we found evidence of an overestimate of VO2 during hyperoxia. After the introduction of a mixing chamber for sampling expired air, the means of the three methods were not significantly different. The variability among the methods was least with the conventional calculation but increased with higher O2 fractions. The average VO2 for submaximal exercise in hyperoxia was not significantly different from that of normoxia. VO2 max was significantly higher in hyperoxia. The increased variability of the Douglas bag method in hyperoxia may lead to overestimates of VO2 max unless special precautions are taken.

Freeze-thaw injury in erythrocytes of the freeze-tolerant wood frog, Rana sylvatica

1991 ◽  
Vol 261 (6) ◽  
pp. R1346-R1350 ◽  
Author(s):  
J. P. Costanzo ◽  
R. E. Lee
Keyword(s):  
Cell Injury ◽  
Osmotic Fragility ◽  
Rana Sylvatica ◽  
Freeze Tolerance ◽  
Wood Frog ◽  
In Vitro Tests ◽  
Freezing And Thawing ◽  
Freeze Tolerant ◽  
High Concentrations

Erythrocytes from the freeze-tolerant wood frog (Rana sylvatica) were subjected to in vitro tests of freeze tolerance, cryoprotection, and osmotic fragility. The responses of cells from frogs acclimated to 4 or 15 degrees C were similar. Erythrocytes that were frozen in saline hemolyzed at -4 degrees C or lower. The addition of high concentrations (150 and 1,500 mM) of glucose or glycerol, cryoprotectants produced naturally by freeze-tolerant frogs, significantly reduced cell injury at -8 degrees C, but concentrations of 1.5 or 15 mM were ineffective. Hemolysis was reduced by 94% with 1,500 mM glycerol and by 84% with 1,500 mM glucose; thus glycerol was the more effective cryoprotectant. Mean fragility values for frog erythrocytes incubated in hypertonic and hypotonic saline were 1,938 and 49 mosM, respectively. Survival in freeze tolerance and cryoprotection experiments was comparable for erythrocytes from frogs and humans, suggesting that these cells may respond similarly to freezing-related stresses. However, the breadth of osmotic tolerance, standardized for differences in isotonicity, was greater for frog erythrocytes than for human erythrocytes. Our data suggest that erythrocytes from R. sylvatica are adequately protected by glucose under natural conditions of freezing and thawing.

Efficiency: an underlying principle of learning?

2018 ◽  
Vol 29 (2) ◽  
pp. 183-197 ◽  
Author(s):  
Sean Commins
Keyword(s):  
Multiple Solutions ◽  
Metabolic Cost ◽  
Descriptive Term ◽  
Underlying Principle ◽  
All Solutions ◽  
Metabolic Costs ◽  
Cost Reductions ◽  
The Brain

AbstractLearning is essential. It allows animals to change circumstances, deal with new situations and adapt to environments. Here, we argue that learning, at behavioral and neural levels, involves efficiency, reflected in metabolic cost reductions. Behaviourally, although multiple solutions to a novel problem may be available, all solutions are not learnt – it is too costly. Furthermore, once a strategy has been selected, it is reinforced producing an efficiency that leads to a maximisation of performance and metabolic cost reductions. Learning can be represented in the brain through many mechanisms; however, if learning is truly efficient, then, all such mechanisms should also be accompanied by a reduction in measurable metabolic costs. By thinking about learning in terms of efficiency, not simply as a descriptive term but rather in terms of metabolic costs, it allows learning to be examined more carefully and provides predictions that can be easily tested (and indeed refuted).

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