Relationship of hepatocyte ploidy levels with body size and growth rate in mammals

Genome ◽  
2001 ◽  
Vol 44 (3) ◽  
pp. 350-360 ◽  
Author(s):  
A E Vinogradov ◽  
O V Anatskaya ◽  
B N Kudryavtsev

To elucidate possible causes of the elevation of genome number in somatic cells, hepatocyte ploidy levels were measured cytofluorimetrically and related to the organismal parameters (body size, postnatal growth rate, and postnatal development type) in 53 mammalian species. Metabolic scope (ratio of maximal metabolic rate to basal metabolic rate) was also included in 23 species. Body masses ranged 105 times, and growth rate more than 30 times. Postnatal growth rate was found to have the strongest effect on the hepatocyte ploidy. At a fixed body mass the growth rate closely correlates (partial correlation analysis) with the cell ploidy level (r = 0.85, P < 10–6), whereas at a fixed growth rate body mass correlates poorly with ploidy level (r = –0.38, P < 0.01). The mature young (precocial mammals) of the species have, on average, a higher cell ploidy level than the immature-born (altricial) animals. However, the relationship between precocity of young and cell ploidy levels disappears when the influences of growth rate and body mass are removed. Interspecies variability of the hepatocyte ploidy levels may be explained by different levels of competition between the processes of proliferation and differentiation in cells. In turn, the animal differences in the levels of this competition are due to differences in growth rate. A high negative correlation between the hepatocyte ploidy level and the metabolic scope indicates a low safety margin of organs with a high number of polyploid cells. This fact allows us to challenge a common opinion that increasing ploidy enhances the functional capability of cells or is necessary for cell differentiation. Somatic polyploidy can be considered a "cheap" solution of growth problems that appear when an organ is working at the limit of its capabilities.Key words: genome number, somatic polyploidy, nuclear ploidy, multinuclearity, metabolic scope.

2006 ◽  
Vol 3 (1) ◽  
pp. 100-103 ◽  
Author(s):  
James F Gillooly ◽  
Andrew P Allen

Debate on the mechanism(s) responsible for the scaling of metabolic rate with body size in mammals has focused on why the maximum metabolic rate ( ) appears to scale more steeply with body size than the basal metabolic rate (BMR). Consequently, metabolic scope, defined as /BMR, systematically increases with body size. These observations have led some to suggest that and BMR are controlled by fundamentally different processes, and to discount the generality of models that predict a single power-law scaling exponent for the size dependence of the metabolic rate. We present a model that predicts a steeper size dependence for than BMR based on the observation that changes in muscle temperature from rest to maximal activity are greater in larger mammals. Empirical data support the model's prediction. This model thus provides a potential theoretical and mechanistic link between BMR and .


1998 ◽  
Vol 76 (5) ◽  
pp. 978-983 ◽  
Author(s):  
Hugo Ochoa-Acuña ◽  
John M Francis ◽  
Daryl J Boness

The objectives of this study were to establish body mass at birth, postnatal growth rate, and the factors that influence these parameters for the Juan Fernández fur seal, Arctocephalus philippii. Females of this species have an unusual attendance pattern in which foraging trips and shore visits last, on average, 12.3 and 5.3 days, respectively. Pup mass was obtained from cohorts born during the reproductive seasons in 1988 through 1992. Birth masses of male and female pups were significantly different, averaging 6.1 and 5.5 kg, respectively (F = 13.2, P < 0.0003, n = 238). Birth masses also differed among cohorts, being lowest in 1992 and highest in 1990. During the first 2 months of life, male and female pups grew at the same rate (79 ± 61.5 g · day-1 (mean ± SD); F[1] = 0.03, P = 0.8562). Interannual differences in growth rate during the first month were significant (F[4] = 8.14, P < 0.0001), as was the interaction between month and year effects (F[2] = 6.81, P = 0.0012). Growth rates for the 1990 cohort were lower than those in all other years except 1992. Birth masses and postnatal growth rates of Juan Fernández fur seal pups are comparable to those of other otariid species.


2016 ◽  
Vol 73 (4) ◽  
pp. 709-715 ◽  
Author(s):  
John P. DeLong ◽  
Matthew Walsh

Predation has been shown to either increase or decrease the body mass of fish, as well as cause variable changes in growth rate. The mechanisms underlying these contrasting responses are not well understood. Here we compared intraspecific body size and growth responses to predation against a backdrop of 2006 estimates of asymptotic mass and growth constants (i.e., von Bertalanffy parameters) across species. We show that intraspecific responses can be quite large relative to interspecific variation and confirm that the magnitude and direction of body size responses is variable. We then employed the supply–demand (SD) model of body mass evolution to explore how predator-induced changes in resource demand or supply could alter body mass. The SD model predicts that any combination of increasing or decreasing body mass and increasing or decreasing growth rate is possible when predation risk is increased, which is consistent with the literature. Finally, we use three case studies to illustrate how the interplay of resource supply and resource demand determines the actual body mass and growth rate response to predation.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5675 ◽  
Author(s):  
Helena Lopes Galasso ◽  
Marion Richard ◽  
Sébastien Lefebvre ◽  
Catherine Aliaume ◽  
Myriam D. Callier

Considering the ecological importance and potential value of Hediste diversicolor, a better understanding of its metabolic rate and potential growth rates is required. The aims of this study are: (i) to describe key biometric relationships; (ii) to test the effects of temperature and body size on standard metabolic rate (as measure by oxygen consumption) to determine critical parameters, namely Arrhenius temperature (TA), allometric coefficient (b) and reaction rate; and (iii) to determine the metabolic scope for activity (MSA) of H. diversicolor for further comparison with published specific growth rates. Individuals were collected in a Mediterranean lagoon (France). After 10 days of acclimatization, 7 days at a fixed temperature and 24 h of fasting, resting oxygen consumption rates (VO2) were individually measured in the dark at four different temperatures (11, 17, 22 and 27 °C) in worms weighing from 4 to 94 mgDW (n = 27 per temperature). Results showed that DW and L3 were the most accurate measurements of weight and length, respectively, among all the metrics tested. Conversion of WW (mg), DW (mg) and L3 (mm) were quantified with the following equations: DW = 0.15 × WW, L3 = 0.025 × TL(mm) + 1.44 and DW = 0.8 × L33.68. Using an equation based on temperature and allometric effects, the allometric coefficient (b) was estimated at 0.8 for DW and at 2.83 for L3. The reaction rate (VO2) equaled to 12.33 µmol gDW−1 h−1 and 0.05 µmol mm L3−1 h−1 at the reference temperature (20 °C, 293.15 K). Arrhenius temperature (TA) was 5,707 and 5,664 K (for DW and L3, respectively). Metabolic scope for activity ranged from 120.1 to 627.6 J gDW−1 d−1. Predicted maximum growth rate increased with temperature, with expected values of 7–10% in the range of 15–20 °C. MSA was then used to evaluate specific growth rates (SGR) in several experiments. This paper may be used as a reference and could have interesting applications in the fields of aquaculture, ecology and biogeochemical processes.


PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0260037
Author(s):  
Henrik H. Berntsen ◽  
Claus Bech

In birds, incubation temperature has received increased attention as an important source of phenotypic variability in offspring. A lower than optimal incubation temperature may negatively affect aspects of nestling physiology, such as body growth and energy metabolism. However, the long-term effects of sub-optimal incubation temperature on morphology and physiology are not well understood. In a previous study, we showed that zebra finches from eggs incubated at a low temperature (35.9°C) for 2/3 of the total incubation time suffered a lower post-fledging survival compared to individuals that had been incubated at higher temperatures (37.0 and 37.9°C). In the present study, we investigated whether these variations in incubation temperature could cause permanent long-lasting differences in body mass, body size, or basal metabolic rate. Furthermore, we tested whether the observed differences in survival between treatment groups would be reflected in the rate of physiological deterioration, assessed through oxidative damage and decreased metabolic rate with age (i.e. ‘metabolic aging’). Incubation temperature did not significantly affect embryonic or nestling body growth and did not influence final adult body mass or body size. Nor was there any long-term effect on basal metabolic rate. Birds from eggs incubated at the lowest temperature experienced an accumulation of oxidative damage with age, although this was not accompanied by an accelerated rate of metabolic aging. The present results suggest that the low survival in these birds was possibly mediated by increased oxidative stress, but independent of body growth and the basal metabolic rate.


Therya ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 105-113
Author(s):  
Matías Martínez-Coronel ◽  
Anubis Molina-Gutiérrez ◽  
Yolanda Hortelano-Moncada

Natalus mexicanus is a bat species distributed from northern México to Central America.  It inhabits various types of tropical vegetation, roosting mainly in caves with high relative humidity and temperature, and feeding mostly on arachnids.  This study investigated postnatal growth and flight development of populations under natural conditions inhabiting “Los Laguitos” cave, Chiapas, southern México.  Forty-four females and 50 males were monitored from birth to 55 days of age; at five-day intervals, we measured body mass, forearm length, cartilaginous epiphyseal gap of the fourth metacarpal-phalangeal joint, and development of four characters.  We used statistical analyses and growth models to quantify the changes in morphometric parameters.  Neonates are altricial; the ears began to unfold since day one, while the eyes opened at day 25.  Greyish hair appeared between 25 to 35 days.  Forearm length and body mass increased linearly over 35 days, then the growth rate decreased.  The cartilaginous epiphyseal gap increased in size until day 25 and then started to close.  The logistic equation yielded the best fit for forearm length (K = 0.07) and body mass (K = 0.10).  Sustained flight was first achieved at 35 days of age.  N. mexicanus neonates are altricial and relatively small compared with other bats.  Eye-opening and fur development took place at a slower rate than in most species of insectivorous bats.  In the Chiapas population, eye-opening, fur development, and volancy occurred more slowly relative to the population inhabiting Álamos, Sonora.  These differences are probably consequences of local variations.  The morphometric postnatal growth pattern of N. mexicanus was like that of other insectivorous bats, i. e., linear growth rate before the onset of flight and slowing down thereafter.  As in other studies, the logistic model best fitted the growth pattern of body mass and forearm length, but growth coefficients were lower versus other tropical bats.  The cartilaginous epiphyseal gap of the fourth digit closes at an intermediate age relative to other insectivorous bats.  Sustained flight was attained when the relative body mass and forearm length of individuals approached adult body dimensions, as in other bat species.


2019 ◽  
Vol 15 (4) ◽  
pp. 20180837 ◽  
Author(s):  
Orvil Grunmeier ◽  
Michael D. D'Emic

Osteocytes are mature versions of osteoblasts, bone-forming cells that develop in two ways: via ‘static’ osteogenesis, differentiating and ossifying tissue in situ to form a scaffold upon which other bone can form, or ‘dynamic’ osteogenesis, migrating to infill or lay down bone around neurovasculature. A previous study regressed the volume of osteocyte lacunae derived from dynamic osteogenesis (DO) of a broad sample of extant bird species against body mass, the growth rate constant ( k ), mass-specific metabolic rate, genome size, and erythrocyte size. There were significant relationships with body mass, growth rate, metabolic rate, and genome size, with the latter being the strongest. Using the same avian histological dataset, we measured over 3800 osteocyte lacunar axes derived from static osteogenesis (SO) in order to look for differences in the strength of form–function relationships inferred for DO-derived lacunae at the cellular and tissue levels. The relationship between osteocyte lacunar volume and body mass was stronger when measuring SO lacunae, whereas relationships between osteocyte lacunar volume versus growth rate and basal metabolic rate disappeared. The relationship between osteocyte lacuna volume and genome size remained significant and moderately strong when measuring SO lacunae, whereas osteocyte lacuna volume was still unrelated to erythrocyte size. Our results indicate that growth and metabolic rate signals are contained in avian DO but not SO osteocyte lacunae, suggesting that the former should be used in estimating these parameters in extinct animals.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12455
Author(s):  
Elisabeth Yarwood ◽  
Claudia Drees ◽  
Jeremy E. Niven ◽  
Wiebke Schuett

Background Individuals within the same species often differ in their metabolic rates, which may covary with behavioural traits (such as exploration), that are consistent across time and/or contexts, and morphological traits. Yet, despite the frequent occurrence of sexual dimorphisms in morphology and behaviour, few studies have assessed whether and how sexes differ in metabolic trait covariances. Methods We investigated sex-specific relationships among resting or active metabolic rate (RMR and AMR, respectively) with exploratory behaviour, measured independently of metabolic rate in a novel environment, body size and body mass, in Carabus hortensis ground beetles. Results RMR, AMR and exploratory behaviour were repeatable among individuals across time, except for male RMR which was unrepeatable. Female RMR neither correlated with exploratory behaviour nor body size/body mass. In contrast, AMR was correlated with both body size and exploratory behaviour. Males with larger body sizes had higher AMR, whereas females with larger body sizes had lower AMR. Both male and female AMR were significantly related to exploratory behaviour, though the relationships between AMR and exploration were body mass-dependent in males and temperature-dependent in females. Discussion Differences between sexes exist in the covariances between metabolic rate, body size and exploratory behaviour. This suggests that selection acts differently on males and females to produce these trait covariances with potentially important consequences for individual fitness.


2007 ◽  
Vol 92 (1) ◽  
pp. 63-76 ◽  
Author(s):  
LAËTITIA MONTES ◽  
NATHALIE LE ROY ◽  
MARTINE PERRET ◽  
VIVIAN DE BUFFRENIL ◽  
JACQUES CASTANET ◽  
...  

2005 ◽  
Vol 2 (1) ◽  
pp. 125-127 ◽  
Author(s):  
Craig R White ◽  
Nicole F Phillips ◽  
Roger S Seymour

Body size and temperature are primary determinants of metabolic rate, and the standard metabolic rate (SMR) of animals ranging in size from unicells to mammals has been thought to be proportional to body mass ( M ) raised to the power of three-quarters for over 40 years. However, recent evidence from rigorously selected datasets suggests that this is not the case for birds and mammals. To determine whether the influence of body mass on the metabolic rate of vertebrates is indeed universal, we compiled SMR measurements for 938 species spanning six orders of magnitude variation in mass. When normalized to a common temperature of 38 °C, the SMR scaling exponents of fish, amphibians, reptiles, birds and mammals are significantly heterogeneous. This suggests both that there is no universal metabolic allometry and that models that attempt to explain only quarter-power scaling of metabolic rate are unlikely to succeed.


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