CO2 release patterns in Drosophila melanogaster: the effect of selection for desiccation resistance.

1997 ◽  
Vol 200 (3) ◽  
pp. 615-624 ◽  
Author(s):  
A E Williams ◽  
M R Rose ◽  
T J Bradley
Keyword(s):  
Drosophila Melanogaster ◽  
Gas Exchange ◽  
Desiccation Resistance ◽  
Strongly Correlated ◽  
Dry Air ◽  
Flow Through ◽  
Selection For ◽  
The Relationship ◽  
Co2 Release

We used laboratory natural selection on insects as a means of investigating the role of patterns of gas exchange in desiccation resistance. We used 15 populations of Drosophila melanogaster: five selected for desiccation resistance, five control populations and five ancestral populations. Using flow-through respirometry, we found that D. melanogaster from all populations produced irregular peaks of CO2 release. To quantify the height and frequency of these peaks, we used the standard error of a linear regression (SER) through the recordings of CO2 release. The values for the SER were significantly larger in the populations selected for desiccation resistance than in the control and ancestral populations. Occasionally, highly periodic peaks of CO2 release were observed in the desiccation-resistant populations only. Maximum SER was found to be strongly correlated with survival time in dry air among selection treatments, but not among individuals within a population. Access to dietary water resulted in lower SER values. These data demonstrate that gas exchange is physiologically controlled in Drosophila melanogaster and that the pattern of gas exchange can change under selection. The relationship between these CO2 release patterns and classic discontinuous ventilation is discussed.

Using laboratory selection for desiccation resistance to examine the relationship between respiratory pattern and water loss in insects.

1998 ◽  
Vol 201 (21) ◽  
pp. 2945-2952 ◽  
Author(s):  
A E Williams ◽  
M R Rose ◽  
T J Bradley
Keyword(s):  
Drosophila Melanogaster ◽  
Water Loss ◽  
Loss Rate ◽  
Respiratory Pattern ◽  
Desiccation Resistance ◽  
Water Loss Rate ◽  
Laboratory Selection ◽  
Selection For ◽  
The Relationship ◽  
Co2 Release

We conducted concurrent measurements of rates of CO2 and H2O release from individual fruit flies Drosophila melanogaster taken from populations subjected to three different selective regimes: (1) populations selected for resistance to desiccation (D flies); (2) populations maintained as their controls (C flies); and (3) the ancestral populations of the D and C populations (O flies). In the D flies, water loss rates were significantly reduced, the standard error of the regression (SER) of the CO2 release pattern measured over the survival period of the flies was increased, and the ratio of CO2 loss to H2O loss (VCO2/VH2O) was increased. Correlations across all 15 populations from the three selection treatments indicate that survival time was negatively correlated with water loss rate, positively correlated with the SER of CO2 release and positively correlated with the VCO2/VH2O ratio. We did not, however, find a significant correlation between the SER of CO2 release and rates of water loss or the VCO2/VH2O ratio.

Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

2003 ◽  
Vol 94 (3) ◽  
pp. 1186-1192 ◽  
Author(s):  
G. Kim Prisk ◽  
Harold J. B. Guy ◽  
John B. West ◽  
James W. Reed
Keyword(s):  
Gas Exchange ◽  
Respiratory Exchange Ratio ◽  
Blood Gases ◽  
Inert Gas ◽  
Phase Iii ◽  
Strongly Correlated ◽  
Arterial Blood Gases ◽  
Arterial Blood ◽  
Expired Gas ◽  
The Relationship

The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (V˙a/Q˙) inequality in the lung. To further validate this estimate, we examined three measures ofV˙a/Q˙ inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of V˙a/Q˙ inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreathV˙a/Q˙ (iV˙/Q˙), the best index was the slope of iV˙/Q˙ vs. volume over phase III (iV˙/Q˙slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV˙/Q˙ slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement ofV˙a/Q˙ inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

Testing the “rate of living” model: further evidence that longevity and metabolic rate are not inversely correlated in Drosophila melanogaster

2004 ◽  
Vol 97 (5) ◽  
pp. 1915-1922 ◽  
Author(s):  
Wayne A. Van Voorhies ◽  
Aziz A. Khazaeli ◽  
James W. Curtsinger
Keyword(s):  
Drosophila Melanogaster ◽  
Metabolic Rate ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Time Of Day ◽  
Metabolic Rates ◽  
Extended Longevity ◽  
Flow Through ◽  
The Relationship

In a recent study examining the relationship between longevity and metabolism in a large number of recombinant inbred Drosophila melanogaster lines, we found no indication of the inverse relationship between longevity and metabolic rate that one would expect under the classical “rate of living” model. A potential limitation in generalizing from that study is that it was conducted on experimental material derived from a single set of parental strains originally developed over 20 years ago. To determine whether the observations made with those lines are characteristic of the species, we studied metabolic rates and longevities in a second, independently derived set of recombinant inbred lines. We found no correlation in these lines between metabolic rate and longevity, indicating that the ability to both maintain a normal metabolic rate and have extended longevity may apply to D. melanogaster in general. To determine how closely our measurements reflect metabolic rates of flies maintained under conditions of life span assays, we used long-term, flow-through metabolic rate measurements and closed system respirometry to examine the effects of variables such as time of day, feeding state, fly density, mobility of the flies, and nitrogen knockout on D. melanogaster metabolic rate. We found that CO2 production estimated in individual flies accurately reflects metabolic rates of flies under the conditions used for longevity assays.

The effect of respiratory pattern on water loss in desiccation-resistant Drosophila melanogaster.

1998 ◽  
Vol 201 (21) ◽  
pp. 2953-2959 ◽  
Author(s):  
A E Williams ◽  
T J Bradley
Keyword(s):  
Drosophila Melanogaster ◽  
Water Loss ◽  
Loss Rate ◽  
Extended Period ◽  
Peak Height ◽  
Respiratory Pattern ◽  
Water Loss Rate ◽  
Selection For ◽  
Reduced Water ◽  
Co2 Release

We measured CO2 and H2O release from individual fruit flies from five populations of Drosophila melanogaster selected for resistance to desiccation (D flies). Our previous work found that these flies survive for an extended period in dry air, have an increase in the peak height and frequency of CO2 release, as measured by the standard error of a linear regression (SER) of CO2 release for the entire survival period, and have reduced water loss rates (VH2O) compared with their control or ancestor populations. In the present study, we examined the following respiratory characteristics: VCO2, VH2O, the SER of CO2 release and the ratio of VCO2 to VH2O in the D flies. Correlations between these characters were calculated in order to determine the effect of respiratory pattern on water loss. We found that, within the D flies, neither periodic release of CO2 nor an increased SER for CO2 release was associated with reduced water loss. In addition, an increased SER was positively correlated with both an increased water loss rate and a decreased survival time. Therefore, although selection for desiccation resistance leads to both an increased SER and a decreased rate of water loss in the D flies, the increased SER does not significantly reduce respiratory water loss.

1. Everything has structure

2014 ◽  
Author(s):  
David Blockley
Keyword(s):  
Decision Making ◽  
Structural Engineering ◽  
Fitness For Purpose ◽  
Form And Function ◽  
Environmental Criteria ◽  
Flow Through ◽  
And Function ◽  
Relationship Of ◽  
The Relationship

‘Everything has structure’ considers the fundamental nature and role of structure and the relationship of structural engineering with other engineering disciplines and with architecture. Decision making is driven by the purpose of a man-made structure and how ‘fitness for purpose’ is realised. There is a need to understand how forces flow through a structure in order to ensure it meets its primary purpose of being strong and safe whilst at the same time meeting many other needs such as affordability, aesthetic, and regulatory and environmental criteria. The best structures are a harmony of architecture and engineering—where form and function are one and the flow of forces is logical.

The effect of selection for desiccation resistance on cold tolerance of Drosophila melanogaster

2007 ◽  
Vol 32 (4) ◽  
pp. 322-327 ◽  
Author(s):  
BRENT J. SINCLAIR ◽  
SEAN NELSON ◽  
THERESA L. NILSON ◽  
STEPHEN P. ROBERTS ◽  
ALLEN G. GIBBS
Keyword(s):  
Drosophila Melanogaster ◽  
Cold Tolerance ◽  
Desiccation Resistance ◽  
Selection For

scholarly journals The Relationship of Intra-Individual Release Variability with Distance and Shooting Performance in Basketball

2021 ◽  
pp. 508-515
Author(s):  
Nathan Slegers ◽  
Davin Lee ◽  
Grant Wong
Keyword(s):  
Control Release ◽  
Body Motion ◽  
Strongly Correlated ◽  
Lower Body ◽  
Basketball Players ◽  
Gradient Based ◽  
Relationship Of ◽  
The Relationship ◽  
Basketball Shooting

The aim of this study was to investigate the role of release parameter changes within individuals (intra-individual) on basketball shooting performance across both free throws and three-point shots, and identify whether any velocity dependence exists. Twelve male basketball players were recorded shooting seventy-five three-point shots (6.75 m) and fifty free throws (4.19 m). Ball release parameters were estimated by combining an analytic trajectory model including drag, a least squares estimator, and gradient-based release distance compensation. Intra-individual release velocity standard deviations (SD) were found to be significantly smaller across all distances ([0.05-0.13 m/s] when compared to statistics reported by other studies [0.2-0.8 m/s]). Despite an increase in lower body motion and a 24% increase in release velocity (p < 0.001) as shooting distance increased, no increases in intra-individual release velocity or angle SD were observed indicating velocity-dependent changes in release parameters were absent. Shooting performance was found to be strongly correlated to the release velocity SD (r = -0.96, p < 0.001, for three-point shots, and r = -0.88, p < 0.001, for free throws). Release angle SD (1.2 ± 0.24 deg, for three-point shots, and 1.3 ± 0.26 deg, for free throws) showed no increase with distance and unrelated to performance. These findings suggest that velocity-dependent factors have minimal contribution to shooting strategies and an individual’s ability to control release velocity at any distance is a primary factor in determining their shooting performance.

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