scholarly journals Implications of density-dependent juvenile growth for compensatory recruitment regulation of haddock

1999 ◽  
Vol 56 (3) ◽  
pp. 356-363 ◽  
Author(s):  
C Tara Marshall ◽  
Kenneth T Frank
Keyword(s):  
Body Size ◽  
Temporal Trends ◽  
The United States ◽  
The Body ◽  
Bay Of Fundy ◽  
Compensatory Mechanism ◽  
Density Dependent ◽  
Positive Correlation ◽  
Dependent Growth ◽  
Adult Abundance

Data from bottom trawl surveys conducted by Canada and the United States were used to describe temporal trends in the length of haddock ages 1-4 on the southwestern Scotian Shelf (SWSS) and Bay of Fundy. From 1970 to 1995, the length of juvenile (age-1) haddock on the SWSS was negatively correlated with the abundance of adults (age-4+). Within year-classes temporal trends in juvenile length persisted through to the adult stage such that year-classes that were small(large) at age-1 were small(large) at age-4. These two results were combined with the positive correlation observed between recruitment and the body size characteristics of haddock on the SWSS in a conceptual model of compensatory recruitment regulation. In the model high adult abundance decreases growth of juveniles leading to smaller-sized adults and subsequently lower recruitment. Conversely, low adult abundance results in increased growth of juveniles leading to larger adults and higher recruitment. Density-dependent growth of juveniles, combined with the positive correlation between recruitment and adult body size, constitutes a compensatory mechanism for adjusting future haddock recruitment according to present adult abundance.

A Coupled Model of LV Growth and Mechanics Applied to Pressure Overload Hypertrophy

2013 ◽  
Author(s):  
G. E. Farrar ◽  
A. I. Veress
Keyword(s):  
Predictive Modeling ◽  
Treatment Strategies ◽  
Coupled Model ◽  
Pressure Overload ◽  
The United States ◽  
The Body ◽  
Systemic Hypertension ◽  
Compensatory Mechanism ◽  
Hypertrophic Growth ◽  
Disease Mechanisms

Hypertension currently affects approximately one third the population in the United States, and represents a major economic burden on the health care system with an estimated annual direct and indirect cost of $50.6 billion [1]. In the case of systemic hypertension, the left ventricle (LV) must work against increased pressure load to pump blood to the body. Over time, this excessive work causes hypertrophy of the myocardium (thickening of the myofibers). While initially a compensatory mechanism, hypertrophy can eventually lead to heart failure (HF) [2]. Predictive modeling of the hypertrophic growth will lead to a better understanding of the disease mechanisms, which in turn has the potential to lead to better treatment strategies.

scholarly journals Cell size and fat content of dietary-restricted Caenorhabditis elegans are regulated by ATX-2, an mTOR repressor

2016 ◽  
Vol 113 (32) ◽  
pp. E4620-E4629 ◽  
Author(s):  
Daniel Z. Bar ◽  
Chayki Charar ◽  
Jehudith Dorfman ◽  
Tam Yadid ◽  
Lionel Tafforeau ◽  
...  
Keyword(s):  
Body Size ◽  
Caenorhabditis Elegans ◽  
Cell Size ◽  
Fat Content ◽  
Mtor Pathway ◽  
The Body ◽  
Dependent Growth ◽  
Multiple Species ◽  
Amp Activated Protein Kinase ◽  
Gdp Dissociation Inhibitor

Dietary restriction (DR) is a metabolic intervention that extends the lifespan of multiple species, including yeast, flies, nematodes, rodents, and, arguably, rhesus monkeys and humans. Hallmarks of lifelong DR are reductions in body size, fecundity, and fat accumulation, as well as slower development. We have identified atx-2, the Caenorhabditis elegans homolog of the human ATXN2L and ATXN2 genes, as the regulator of these multiple DR phenotypes. Down-regulation of atx-2 increases the body size, cell size, and fat content of dietary-restricted animals and speeds animal development, whereas overexpression of atx-2 is sufficient to reduce the body size and brood size of wild-type animals. atx-2 regulates the mechanistic target of rapamycin (mTOR) pathway, downstream of AMP-activated protein kinase (AMPK) and upstream of ribosomal protein S6 kinase and mTOR complex 1 (TORC1), by its direct association with Rab GDP dissociation inhibitor β, which likely regulates RHEB shuttling between GDP-bound and GTP-bound forms. Taken together, this work identifies a previously unknown mechanism regulating multiple aspects of DR, as well as unknown regulators of the mTOR pathway. They also extend our understanding of diet-dependent growth retardation, and offers a potential mechanism to treat obesity.

scholarly journals Social selection is density dependent but makes little contribution to total selection in New Zealand giraffe weevils

2021 ◽  
Author(s):  
David N Fisher ◽  
Rebecca J LeGrice ◽  
Christina J Painting
Keyword(s):  
Body Size ◽  
New Zealand ◽  
Evolutionary Change ◽  
The Body ◽  
Direct Selection ◽  
Social Selection ◽  
Density Dependent ◽  
Phenotypic Assortment ◽  
Body Sizes ◽  
Total Selection

AbstractSocial selection occurs when traits of interaction partners influence an individual’s fitness and can fundamentally alter total selection strength. Unlike for direct selection, however, we have little idea of what factors influence the strength of social selection. Further, social selection only contributes to overall selection when there is phenotypic assortment, but simultaneous estimates of social selection and phenotypic assortment are rare. Here we estimated social selection on body size in a wild population of New Zealand giraffe weevils (Lasiorhynchus barbicornis). We did this in a range of contexts and measured phenotypic assortment for both sexes. Social selection was mostly absent and not affected by sex ratio or the body size of the focal individual. However, at high densities selection was negative for both sexes, consistent with competitive interactions based on size for access to mates. Phenotypic assortment was also density dependent, flipping from positive at low densities to negative at high densities. However, it was always close to zero, indicating negative social selection at high densities will not greatly impede the evolution of larger body sizes. Despite its predicted importance, social selection may only influence evolutionary change in specific contexts, leaving direct selection as the dominant driver of evolutionary change.

Bioenergetics of Stock and Recruitment

1980 ◽  
Vol 37 (6) ◽  
pp. 1012-1024 ◽  
Author(s):  
D. M. Ware
Keyword(s):  
Life History ◽  
Body Size ◽  
Optimal Foraging ◽  
Reproductive Effort ◽  
Clupea Harengus ◽  
Recruitment Curve ◽  
Density Dependent ◽  
Surplus Energy ◽  
Dependent Growth ◽  
Stock And Recruitment

A new concept of recruitment is derived from bioenergetic considerations of life history phenomena. The proposed mechanism has two components, a stock-dependent process where individual reproductive effort is a decreasing function of the abundance of the mature stock, and a density-dependent mortality process which operates during the prerecruit stage. A generalized equation describing these processes yields a family of recruitment curves which vary from being asymptotic to dome-shaped, depending on the parameter values. The theory suggests that species like Atlantic herring (Clupea harengus harengus) which tend to have small density-dependent growth coefficients and which allocate most of their surplus energy to reproduction should have a small terminal body size, a high length at maturity to L∞ ratio, and a nearly asymptotic recruitment curve. By contrast, gadoids follow a different life history strategy and therefore should have a higher L∞ and more convex recruitment function. These consequences are shown to be in accord with observed differences in L∞ and with the graded series of recruitment curves found for a wide range of marine fish stocks. From a more general viewpoint, analysis of the energy dynamics of natural populations suggests that (1) there is a real — as opposed to inferred — limit to growth, L∞, which in many species is probably determined by their reproductive effort; (2) the increase in surplus energy with body size can be linked to the theory of optimal foraging; and (3) the intensity of density-dependent growth, which influences the shape of the recruitment curve, is an increasing function of the generation time of the prey organisms of different species. Thus gadoids tend to have dome-shaped reproduction curves because they feed on slow-maturing prey, which can be overcropped by large year-classes.Key words: stock and recruitment, bioenergetics, optimal foraging, growth, reproduction, life history strategies

scholarly journals Prenatal Cannabinoid Exposure Impacts Offspring's Health in Sickle Mice

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 14-15
Author(s):  
Christopher M Ventura ◽  
Stacy B Kiven ◽  
Nils Lambrecht ◽  
Kalpna Gupta
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Pregnant Women ◽  
Litter Size ◽  
Research Funding ◽  
Hind Limb ◽  
Weight Ratio ◽  
The United States ◽  
The Body ◽  
Study Cohort

Cannabis use is rising amongst pregnant women. An estimated 4% of pregnant women in the United States use cannabis, but, in California approximately 20% of 18-24-year-old pregnant women in a study cohort reported using cannabis (Young-Wolff et al JAMA 2017). Cannabis and cannabinoid use are relatively higher in patients with sickle cell disease (SCD) compared to the general population, perhaps due to pain. Majority of SCD patients in the Western world are on hydroxyurea (HU), which improves survival. However, HU is not prescribed to SCD patients who become pregnant, which may increase the likelihood of cannabinoid use to control pain. This may have devastating consequences as even a single dose of synthetic- (CP 55940) or phyto-cannabinoids (cannabidiol or Δ9-tetrahydrocannabinol) when administered to pregnant C57BL/6 mice on day 8 of gestation produced developmental changes in the offspring. (Fish et al Sci. Rep. 2019). Thus, we hypothesized that cannabinoid use during pregnancy will have teratogenic effects on the offspring's health in SCD. Using humanized transgenic Berkeley sickle (HbSS) and hemizygous (HbAS) mice and control mice expressing normal human hemoglobin A (HbAA), we examined the effect of chronic maternal cannabinoid exposure on the health outcomes of their offsprings. We paired hemizygous AS Berkeley females (homozygous SS Berkeley females do not breed well) with homozygous SS Berkeley males, while AA control mice were paired with each other. Females were treated with HU (i.p., 50 mg/kg/day) for two weeks prior to pairing with a male. Female mice were then treated with CP55940 (CP; i.p., 0.3 mg/kg/day) or vehicle (Veh; 2% DMSO in sterile saline) during breeding until the pups were born (~3 weeks). A subset of females were left untreated to assess baseline measures. At birth, we recorded: [a] litter size, [b] body weight, [c] body size (crown to rump length), [d] right and left eye diameters, and [e] front- and hind-limb lengths. High-resolution digital images were acquired to quantify these parameters. At P21 pups were weighed and euthanized then their organs were collected, weighed, and fixed in formalin. Observations at birth: Use of HU in AS females yielded a larger mean litter size than those of untreated AS females (8.5 vs 5.5 pups/litter). No difference in mean litter size of AA mice treated with HU was observed. The body weight between offspring of AA mice treated with HU+Veh and HU+CP was not significantly different. However, in both the offspring of AA mice and AS/SS mice treated with HU+CP, we observed a ~20% decrease in body weight compared to the untreated AA (p<0.001) and AS/SS (p<0.001) offspring. We observed a similar 20% decrease in body weight between the offspring of AA mice treated with HU+Veh and untreated AA offspring (20%, p<0.001), while no decrease in body weight was observed between AS/SS offspring treated with HU+Veh and untreated AS/SS offspring. Taken together, these data show that maternal cannabinoid treatment leads to a significant decrease in the body weight of offspring. Observations at post-natal day 21: Significant decreases in mean body size (5%, p<0.01) and right eye diameters (8%, p<0.01 & 7%, p<0.05) were seen in the offspring of AA mice treated with HU+CP compared to HU+Veh. Offspring of AS/SS mice treated with HU+CP showed reduced mean body size (~9%, p<0.001), reduced right and left eye diameters (20%, p<0.001 & 19%, p<0.001 respectively), and reduced front and hind limb lengths (21%, p<0.001 & 16%, p<0.001 respectively) compared to those treated with HU+ Veh. In addition, the offspring of AS/SS mice treated with HU+CP had about a 20% decrease in the ratio of brain to body weight compared to HU+Veh treated AS/SS mice (p<0.001). No significant differences in mean litter size, body weight, front and hind limb length and brain weight to body weight ratio were observed between offspring of AA mice treated with HU+Veh and HU+CP. Our data suggest that development/growth of the offspring's body and brain may be hindered by pre-natal cannabinoid exposure and that chronic parental cannabinoid use during pregnancy has a more substantial adverse impact on offspring's health in sickle mice than in control mice. Our data raise concern for cannabinoid use during pregnancy in SCD, which may have adverse effects on the offspring's health and therefore requires monitoring in prospective clinical studies. Disclosures Gupta: CSL Behring: Honoraria; Tautona Group: Honoraria; Novartis: Honoraria; Grifols: Research Funding; 1910 Genetics: Research Funding; Cyclerion: Research Funding.

scholarly journals Geographic body size variation of a tropical anuran: effects of water deficit and precipitation seasonality on Asian common toad from southern Asia

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Cheng Guo ◽  
Shuai Gao ◽  
Ali Krzton ◽  
Long Zhang
Keyword(s):  
Body Size ◽  
Water Deficit ◽  
Size Variation ◽  
The Body ◽  
Environmental Data ◽  
Common Toad ◽  
Tropical Regions ◽  
Positive Correlation ◽  
Body Size Variation ◽  
The Relationship

Abstract Background Two previous studies on interspecific body size variation of anurans found that the key drivers of variation are the species’ lifestyles and the environments that they live in. To examine whether those findings apply at the intraspecific level, we conducted a study of the Asian common toad (Duttaphrynus melanostictus), a terrestrial anuran distributed in tropical regions. The body size of toads from 15 locations, covering the majority of their geographic range, and local environmental data were summarized from published literature. We used a model selection process based on an information-theoretic approach to examine the relationship between toad body size and those environmental parameters. Results We found a positive correlation between the body size of the Asian common toad and the water deficit gradient, but no linkage between body size and temperature-related parameters. Furthermore, there was a positive correlation between the seasonality of precipitation and body size of females from different sampled populations. Conclusions As a terrestrial anuran, the Asian common toad should experience greater pressure from environmental fluctuations than aquatic species. It is mainly distributed in tropical regions where temperatures are generally warm and stable, but water availability fluctuates. Therefore, while thermal gradients are not strong enough to generate selection pressure on body size, the moisture gradient is strong enough to select for larger size in both males and females in dryer regions. Larger body size supports more efficient water conservation, a pattern in accordance with the prediction that lifestyles of different species and their local habitats determine the relationship between body size and environment. In addition, larger females occur in regions with greater seasonality in precipitation, which may happen because larger females can afford greater reproductive output in a limited reproductive season.

Density-Dependent Growth in Early Ocean Life of Sockeye Salmon (Oncorhynchus nerka)

1984 ◽  
Vol 41 (12) ◽  
pp. 1825-1829 ◽  
Author(s):  
Randall M. Peterman
Keyword(s):  
British Columbia ◽  
Body Size ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Management Strategies ◽  
Gulf Of Alaska ◽  
Density Dependent ◽  
Adult Body Size ◽  
Adult Body ◽  
Dependent Growth

Significant decreases in adult body size and marine growth rate occur in seven British Columbia and Bristol Bay, Alaska, sockeye salmon (Oncorhynchus nerka) stocks when large numbers of sockeye are present in the Gulf of Alaska. These density-dependent effects arise mainly during early ocean life and are probably due to competition for food. The total sockeye abundance in the Gulf of Alaska is at least as important as within-stock abundance in determining final adult body size. British Columbia sockeye show a 10–22% decrease in adult body weight at high abundance of conspecifics. Thus, future evaluations of management strategies cannot simply focus on individual stocks, but must take a broader perspective which includes other sockeye populations.

Estimation of body condition in harbour porpoises, Phocoena phocoena

1990 ◽  
Vol 68 (9) ◽  
pp. 1962-1966 ◽  
Author(s):  
Andrew J. Read
Keyword(s):  
Body Size ◽  
Body Condition ◽  
The Body ◽  
Bay Of Fundy ◽  
Commercial Fishing ◽  
Direct Measure ◽  
Phocoena Phocoena ◽  
Indirect Measures ◽  
Lactating Females ◽  
Residual Values

I examined the body condition of 220 harbour porpoises (Phocoena phocoena) killed incidentally in commercial fishing operations in the Bay of Fundy between July and September, 1985–1988. Condition was assessed using a direct measure (blubber mass) and two indirect measures (blubber thickness and girth). To compare condition among porpoises of different sizes, each measure was regressed against an appropriate measure of body size, and the residuals of these regressions were used as indices of condition. Mean residuals of blubber mass varied significantly among both reproductive classes and sampling years. Calves and nonlactating mature females had greater mean residual values for blubber mass than immature porpoises and mature males; lactating females possessed intermediate levels. Porpoises sampled in 1987 had greater mean residual blubber mass than porpoises sampled in other years. Although the residuals of girth and blubber thickness demonstrated similar trends to those of blubber mass, they were poorly correlated with the residuals of blubber mass and are not robust indices of condition in harbour porpoises.

Effects of witnessing fat talk on body satisfaction and psychological well-being: A cross-cultural comparison of Korea and the United States

2013 ◽  
Vol 41 (8) ◽  
pp. 1279-1295 ◽  
Author(s):  
Hye Eun Lee ◽  
Emiko Taniguchi ◽  
Alisa Modica ◽  
Hyunjin Park
Keyword(s):  
Weight Loss ◽  
Body Size ◽  
Body Satisfaction ◽  
Well Being ◽  
The United States ◽  
The Body ◽  
Online Questionnaire ◽  
Psychological Well Being ◽  
Fat Talk ◽  
The U.S

We examined how witnessing fat talk on Facebook influenced the body satisfaction and psychological well-being of Korean and U.S. young women. Korean (n = 137) and U.S. (n = 159) women completed an online questionnaire after viewing a randomly assigned mock-up Facebook page where body size of the profile owner and the messages from her peers were manipulated. Findings showed that (a) Koreans witnessing an underweight peer's fat talk reported lower body satisfaction than did those witnessing an overweight peer's fat talk, but the peer's body size did not affect the U.S. women, and (b) Koreans witnessing messages discouraging weight loss reported greater psychological well-being than did those witnessing messages promoting weight loss, whereas peers' comments did not influence the U.S. women.

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