Selected Contribution: Long-lived Drosophila melanogaster lines exhibit normal metabolic rates

2003 ◽  
Vol 95 (6) ◽  
pp. 2605-2613 ◽  
Author(s):  
Wayne A. Van Voorhies ◽  
Aziz A. Khazaeli ◽  
James W. Curtsinger
Keyword(s):  
Drosophila Melanogaster ◽  
Metabolic Rate ◽  
A Priori ◽  
Model Organisms ◽  
Large Set ◽  
Metabolic Rates ◽  
Powerful Method ◽  
Wide Range ◽  
The Relationship ◽  
Average Adult

The use of model organisms, such as Drosophila melanogaster, provides a powerful method for studying mechanisms of aging. Here we report on a large set of recombinant inbred (RI) D. melanogaster lines that exhibit approximately a fivefold range of average adult longevities. Understanding the factors responsible for the differences in longevity, particularly the characteristics of the longest-lived lines, can provide fundamental insights into the mechanistic correlates of aging. In ectothermic organisms, longevity is often inversely correlated with metabolic rate, suggesting the a priori hypothesis that long-lived lines will have low resting metabolic rates. We conducted ∼6,000 measurements of CO2 production in individual male flies aged 5, 16, 29, and 47 days postemergence and simultaneously measured the weight of individual flies and life spans in populations of each line. Even though there was a wide range of longevities, there was no evidence of an inverse relationship between the variables. The increased longevity of long-lived lines is not mediated through reduction of metabolic activity. In Drosophila, it is possible to both maintain a normal metabolic rate and achieve long life. These results are evaluated in the context of 100 years of research on the relationship between metabolic rate and life span.

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.

scholarly journals Supplier-initiating risk management behaviour and supply-side resilience: the effects of interpersonal relationships and dependence asymmetry in buyer-supplier relationships

2020 ◽  
Vol 40 (7/8) ◽  
pp. 971-995
Author(s):  
Yiyi Fan ◽  
Mark Stevenson ◽  
Fang Li
Keyword(s):  
Risk Management ◽  
Interpersonal Relationships ◽  
Supply Side ◽  
Large Set ◽  
Supplier Relationships ◽  
Content Type ◽  
Management Behaviour ◽  
Wide Range ◽  
Dependence Asymmetry ◽  
The Relationship

PurposeThe aim of the study is to explore how two dimensions of interpersonal relationships (i.e. size and range of relationships) affect supplier-initiating risk management behaviours (SIRMB) and supply-side resilience. Further, the study aims to explore the moderating role of dependence asymmetry.Design/methodology/approachNine hypotheses are tested based on a moderated mediation analysis of survey data from 247 manufacturing firms in China. The data are validated using a subset of 57 attentive secondary respondents and archival data.FindingsSIRMB positively relates to supply-side resilience. Further, SIRMB mediates the positive relationship between range and supply-side resilience, and this relationship is stronger at lower levels of dependence asymmetry. Yet, although dependence asymmetry positively moderates the relationship between range and SIRMB, it negatively moderates the relationship between size and SIRMB. We did not, however, find evidence that size has a conditional indirect effect on supply-side resilience through SIRMB.Practical implicationsManagers in buying firms can incentivise SIRMB to enhance supply-side resilience by developing a diverse rather than a large set of interpersonal relationships with a supplier. This might include allocating particular employees with a wide range of contacts within a supplier to that relationship, while it may be necessary to adopt different networking strategies for different supplier relationships. Firms in a highly asymmetrical relationship may seek to raise supplier expectations about the necessity to initiate risk management behaviour or look to change the dynamic of the relationship by managing contracts for fairness.Originality/valueNew knowledge on SIRMB as a mediating variable underpinning the relationship between interpersonal relationships and supply-side resilience is provided; and empirical evidence on the opposing moderation effect of dependence asymmetry is presented.

Effects of mothers' education on parenting: an investigation across three generations

2005 ◽  
Author(s):  
Kathryn Duckworth ◽  
Ricardo Sabates
Keyword(s):  
Maternal Education ◽  
Family Background ◽  
Cognitive Stimulation ◽  
Large Set ◽  
Background Characteristics ◽  
National Child Development Study ◽  
Confounding Bias ◽  
Wide Range ◽  
Using Data ◽  
The Relationship

The paper investigates the relationship between mother's education and her parenting using data from the child supplement of the 1958 National Child Development Study (NCDS). By considering data across generations, our dataset allows us to estimate the size of the bias in the relationship between education and parenting from failing to account for background characteristics, early cognitive development and mother's own parenting experiences. The subjects were 1,182 longitudinally sampled mothers of 1,879 children aged between 3 and 18 years old and divided approximately equally across gender (51% sons, 49% daughters). Controlling for a wide range of family background variables and mother's own achievement prior to 16, results indicate a confounding bias of 73% for cognitive stimulation and 89% for emotional support. This confounding bias is larger for daughters than for sons. Even after the inclusion of a large set of controls, a small effect of maternal education on parenting, assessed in terms of the provision of a cognitively stimulating environment, remains statistically significant but only for sons. Although educational effects estimated here suffer from downwards bias owing to under-representation of older mothers within the data, some unobserved factors could remain as a source of bias.

scholarly journals Basal metabolic rate of birds is associated with habitat temperature and precipitation, not primary productivity

2006 ◽  
Vol 274 (1607) ◽  
pp. 287-293 ◽  
Author(s):  
Craig R White ◽  
Tim M Blackburn ◽  
Graham R Martin ◽  
Patrick J Butler
Keyword(s):  
Metabolic Rate ◽  
Primary Productivity ◽  
Generalized Least Squares ◽  
Arid Environments ◽  
Metabolic Rates ◽  
Habitat Temperature ◽  
Ambient Temperatures ◽  
Temperature And Precipitation ◽  
The World ◽  
The Relationship

A classic example of ecophysiological adaptation is the observation that animals from hot arid environments have lower basal metabolic rates (BMRs, ml O 2  min −1 ) than those from non-arid (luxuriant) ones. However, the term ‘arid’ conceals within it a multitude of characteristics including extreme ambient temperatures ( T a , °C) and low annual net primary productivities (NPPs, g C m −2 ), both of which have been shown to correlate with BMR. To assess the relationship between environmental characteristics and metabolic rate in birds, we collated BMR measurements for 92 populations representing 90 wild-caught species and examined the relationships between BMR and NPP, T a , annual temperature range ( T r ), precipitation and intra-annual coefficient of variation of precipitation ( P CV ). Using conventional non-phylogenetic and phylogenetic generalized least-squares approaches, we found no support for a relationship between BMR and NPP, despite including species captured throughout the world in environments spanning a 35-fold range in NPP. Instead, BMR was negatively associated with T a and T r , and positively associated with P CV .

scholarly journals Why mammalian lineages respond differently to sexual selection: metabolic rate constrains the evolution of sperm size

2011 ◽  
Vol 278 (1721) ◽  
pp. 3135-3141 ◽  
Author(s):  
Montserrat Gomendio ◽  
Maximiliano Tourmente ◽  
Eduardo R. S. Roldan
Keyword(s):  
Sexual Selection ◽  
Body Size ◽  
Metabolic Rate ◽  
Sperm Competition ◽  
Small Mammals ◽  
High Mass ◽  
Metabolic Rates ◽  
Wide Range ◽  
Low Mass ◽  
Sperm Size

The hypothesis that sperm competition should favour increases in sperm size, because it results in faster swimming speeds, has received support from studies on many taxa, but remains contentious for mammals. We suggest that this may be because mammalian lineages respond differently to sexual selection, owing to major differences in body size, which are associated with differences in mass-specific metabolic rate. Recent evidence suggests that cellular metabolic rate also scales with body size, so that small mammals have cells that process energy and resources from the environment at a faster rate. We develop the ‘metabolic rate constraint hypothesis’ which proposes that low mass-specific metabolic rate among large mammals may limit their ability to respond to sexual selection by increasing sperm size, while this constraint does not exist among small mammals. Here we show that among rodents, which have high mass-specific metabolic rates, sperm size increases under sperm competition, reaching the longest sperm sizes found in eutherian mammals. By contrast, mammalian lineages with large body sizes have small sperm, and while metabolic rate (corrected for body size) influences sperm size, sperm competition levels do not. When all eutherian mammals are analysed jointly, our results suggest that as mass-specific metabolic rate increases, so does maximum sperm size. In addition, species with low mass-specific metabolic rates produce uniformly small sperm, while species with high mass-specific metabolic rates produce a wide range of sperm sizes. These findings support the hypothesis that mass-specific metabolic rates determine the budget available for sperm production: at high levels, sperm size increases in response to sexual selection, while low levels constrain the ability to respond to sexual selection by increasing sperm size. Thus, adaptive and costly traits, such as sperm size, may only evolve under sexual selection when metabolic rate does not constrain cellular budgets.

scholarly journals Heart rate reveals torpor at high body temperatures in lowland tropical free-tailed bats

2017 ◽  
Vol 4 (12) ◽  
pp. 171359 ◽  
Author(s):  
M. Teague O'Mara ◽  
Sebastian Rikker ◽  
Martin Wikelski ◽  
Andries Ter Maat ◽  
Henry S. Pollock ◽  
...  
Keyword(s):  
Heart Rate ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Ambient Temperature ◽  
The Body ◽  
Metabolic Rates ◽  
Body Temperatures ◽  
Wide Range ◽  
Save Energy ◽  
Molossus Molossus

Reduction in metabolic rate and body temperature is a common strategy for small endotherms to save energy. The daily reduction in metabolic rate and heterothermy, or torpor, is particularly pronounced in regions with a large variation in daily ambient temperature. This applies most strongly in temperate bat species (order Chiroptera), but it is less clear how tropical bats save energy if ambient temperatures remain high. However, many subtropical and tropical species use some daily heterothermy on cool days. We recorded the heart rate and the body temperature of free-ranging Pallas' mastiff bats ( Molossus molossus ) in Gamboa, Panamá, and showed that these individuals have low field metabolic rates across a wide range of body temperatures that conform to high ambient temperature. Importantly, low metabolic rates in controlled respirometry trials were best predicted by heart rate, and not body temperature . Molossus molossus enter torpor-like states characterized by low metabolic rate and heart rates at body temperatures of 32°C, and thermoconform across a range of temperatures. Flexible metabolic strategies may be far more common in tropical endotherms than currently known.

scholarly journals Sources and significance of variation in basal, summit and maximal metabolic rates in birds

2010 ◽  
Vol 56 (6) ◽  
pp. 741-758 ◽  
Author(s):  
Andrew E. Mckechnie ◽  
David L. Swanson
Keyword(s):  
Metabolic Rate ◽  
Power Output ◽  
Power Production ◽  
Evolutionary Significance ◽  
Metabolic Reaction ◽  
Metabolic Rates ◽  
Metabolic Power ◽  
Metabolic Diversity ◽  
Upper Limits ◽  
The Relationship

Abstract The rates at which birds use energy may have profound effects on fitness, thereby influencing physiology, behavior, ecology and evolution. Comparisons of standardized metabolic rates (e.g., lower and upper limits of metabolic power output) present a method for elucidating the effects of ecological and evolutionary factors on the interface between physiology and life history in birds. In this paper we review variation in avian metabolic rates [basal metabolic rate (BMR; minimum normothermic metabolic rate), summit metabolic rate (Msum; maximal thermoregulatory metabolic rate), and maximal metabolic rate (MMR; maximal exercise metabolic rate)], the factors associated with this variation, the evidence for functional links between these metabolic traits, and the ecological and evolutionary significance of avian metabolic diversity. Both lower and upper limits to metabolic power production are phenotypically flexible traits, and vary in association with numerous ecological and evolutionary factors. For both inter- and intraspecific comparisons, lower and upper limits to metabolic power production are generally upregulated in response to energetically demanding conditions and downregulated when energetic demands are relaxed, or under conditions of energetic scarcity. Positive correlations have been documented between BMR, Msum and MMR in some, but not all studies on birds, providing partial support for the idea of a functional link between lower and upper limits to metabolic power production, but more intraspecific studies are needed to determine the robustness of this conclusion. Correlations between BMR and field metabolic rate (or daily energy expenditure) in birds are variable, suggesting that the linkage between these traits is subject to behavioral adjustment, and studies of the relationship between field and maximal metabolic rates are lacking. Our understanding of avian metabolic diversity would benefit from future studies of: (1) the functional and mechanistic links between lower and upper limits of metabolic power output; (2) the environmental and ecological cues driving phenotypically flexible metabolic responses, and how responses to such cues might impact population responses to climate change; (3) the shapes of metabolic reaction norms and their association with environmental variability; and (4) the relationship of metabolic variation to fitness, including studies of repeatability and heritability of minimum and maximum metabolic power output.

Basal metabolic rate in lambs and young sheep

1974 ◽  
Vol 25 (6) ◽  
pp. 957 ◽  
Author(s):  
NMcC Graham ◽  
TW Searle ◽  
DA Griffiths
Keyword(s):  
Growth Rate ◽  
Body Weight ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Body Weight Gain ◽  
Adult Cattle ◽  
Adult Sheep ◽  
Free Weight ◽  
Wide Range ◽  
Average Adult

Basal metabolic rate (BMR) was determined in 56 crossbred sheep, up to 10 observations being made on each animal between 1 week of age and 2¼ years. The level of feeding was varied amongst the sheep so that there was a wide range in growth rate at each age. BMR was estimated as heat production under standard conditions of fasting. Trends during fasting were studied in four sheep at ages 3 weeks, 2 months and 9 months. The effects on BMR of body weight (or fat-free weight), age, prior growth rate and prior nutrition were examined statistically by estimating the parameters of a series of model equations by a least squares iterative method. Analysis of lamb and sheep data separately and combined showed that all these variates contributed significantly to BMR. Of the variance of BMR, 89% was accounted for in a body weight term, kgx, in which the value of x was not significantly different from ¾ if one or more of the other variates were in the model; x was unity when fat-free weight was used instead of body weight. If body weight was used alone, x was smaller for both lambs and weaners, being c. 0.60; with fat-free weight the values for lambs and weaners were 0.71 and 0.96 respectively. Age, growth rate and level of feeding were of approximately equal importance, together accounting for a further 6% of the total variance. BMR declined by c. 8% per annum and was affected to the extent of 2.8 kJ per gram body weight gain and 46 kJ per MJ digestible energy intake before fasting (all values per 24 hr). Thus an increase in growth rate in a lamb from zero to maximal (0.3 kg/day) caused BMR to increase by 50%, and an increase of food intake by 1 kg/day in an average adult sheep caused BMR to increase by 10%. For any given set of these variates, BMR was 23% higher in milk-fed lambs than in weaned sheep. An equation was derived for sheep in general; the residual standard deviation was c. 300 kJ/24 hr, or 7-8% of BMR in an average adult sheep. Some evidence was cited to show that this equation may be used to predict BMR in growing and adult cattle by multiplying the whole expression by 1.3.

scholarly journals Vision Based Dynamic Thermal Comfort Control Using Fuzzy Logic and Deep Learning

2021 ◽  
Vol 11 (10) ◽  
pp. 4626
Author(s):  
Mahmoud Al-Faris ◽  
John Chiverton ◽  
David Ndzi ◽  
Ahmed Isam Ahmed
Keyword(s):  
Metabolic Rate ◽  
Thermal Comfort ◽  
Action Recognition ◽  
Vision System ◽  
Recognition System ◽  
Indoor Environments ◽  
Metabolic Rates ◽  
Comfort Index ◽  
Wide Range ◽  
Improved Performance

A wide range of techniques exist to help control the thermal comfort of an occupant in indoor environments. A novel technique is presented here to adaptively estimate the occupant’s metabolic rate. This is performed by utilising occupant’s actions using computer vision system to identify the activity of an occupant. Recognized actions are then translated into metabolic rates. The widely used Predicted Mean Vote (PMV) thermal comfort index is computed using the adaptivey estimated metabolic rate value. The PMV is then used as an input to a fuzzy control system. The performance of the proposed system is evaluated using simulations of various activities. The integration of PMV thermal comfort index and action recognition system gives the opportunity to adaptively control occupant’s thermal comfort without the need to attach a sensor on an occupant all the time. The obtained results are compared with the results for the case of using one or two fixed metabolic rates. The included results appear to show improved performance, even in the presence of errors in the action recognition system.

Haemolymph sugar levels in foraging honeybees (Apis mellifera carnica): dependence on metabolic rate and in vivo measurement of maximal rates of trehalose synthesis

2001 ◽  
Vol 204 (15) ◽  
pp. 2709-2716 ◽  
Author(s):  
Jasmina Blatt ◽  
Flavio Roces
Keyword(s):  
Metabolic Rate ◽  
Fat Body ◽  
Sucrose Solution ◽  
Sucrose Concentration ◽  
Sugar Transport ◽  
Metabolic Rates ◽  
Experimental Conditions ◽  
Wide Range ◽  
Sugar Levels ◽  
Trehalose Synthesis

SUMMARY Previous investigations of haemolymph sugar levels in honeybees have reported very different results, probably because different experimental conditions affected the activity levels of the animals. The present study investigated the dependence of haemolymph sugar levels in foraging honeybees on metabolic rate and whether the haemolymph sugar level is regulated. Free-flying foraging bees were trained to collect controlled amounts of sucrose solution of different concentrations (15%, 30% or 50% sucrose w/w). Immediately after feeding, metabolic rate was measured over a given time depending on the sucrose concentration, then crop-emptying rate and haemolymph sugar levels were measured. Bees exhibiting a wide range of metabolic rates were compared to establish whether the observed differences in haemolymph sugar levels were due to limits in the supply of sugars from the crop or in the rate of trehalose synthesis in the fat bodies. Independent of the concentration of the sucrose solution supplied, haemolymph trehalose, glucose and fructose levels were constant for metabolic rates from 0 to 4.5mlCO2h−1. At higher metabolic rates, trehalose concentration decreased while that of glucose and fructose increased, with the exception of bees fed 15% sucrose solution. As the supply of sugar from the crop via the proventriculus was sufficient to support even the highest metabolic rates, the observed pattern must result from an upper limit in the capacity of the fat body to synthesise trehalose. The maximal rate of conversion of glucose to trehalose in the fat body was therefore calculated to average 92.4μgglucosemin−1. However, for bees fed 15% sucrose solution both the rate of conversion of glucose to trehalose and the rate of sugar transport from the crop to the ventricle were limited, together resulting in a decrease in total haemolymph sugar levels for metabolic rates higher than 5mlCO2h−1.

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