scholarly journals Translating environmental gradients into discontinuous reaction norms via hormone signalling in a polyphenic butterfly

2010 ◽  
Vol 278 (1706) ◽  
pp. 789-797 ◽  
Author(s):  
Vicencio Oostra ◽  
Maaike A. de Jong ◽  
Brandon M. Invergo ◽  
Fanja Kesbeke ◽  
Franziska Wende ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Hormonal Regulation ◽  
Environmental Gradients ◽  
Developmental Trajectories ◽  
Reaction Norms ◽  
Bicyclus Anynana ◽  
Linear Temperature ◽  
Linear Temperature Gradient ◽  
Adult Fitness ◽  
Hormone Signalling

Polyphenisms—the expression of discrete phenotypic morphs in response to environmental variation—are examples of phenotypic plasticity that may potentially be adaptive in the face of predictable environmental heterogeneity. In the butterfly Bicyclus anynana , we examine the hormonal regulation of phenotypic plasticity that involves divergent developmental trajectories into distinct adult morphs for a suite of traits as an adaptation to contrasting seasonal environments. This polyphenism is induced by temperature during development and mediated by ecdysteroid hormones. We reared larvae at separate temperatures spanning the natural range of seasonal environments and measured reaction norms for ecdysteroids, juvenile hormones (JHs) and adult fitness traits. Timing of peak ecdysteroid, but not JH titres, showed a binary response to the linear temperature gradient. Several adult traits (e.g. relative abdomen mass) responded in a similar, dimorphic manner, while others (e.g. wing pattern) showed a linear response. This study demonstrates that hormone dynamics can translate a linear environmental gradient into a discrete signal and, thus, that polyphenic differences between adult morphs can already be programmed at the stage of hormone signalling during development. The range of phenotypic responses observed within the suite of traits indicates both shared regulation and independent, trait-specific sensitivity to the hormone signal.

scholarly journals Chromatin structure changes in Daphnia populations upon exposure to environmental cues – or – The discovery of Wolterecks “Matrix”

2019 ◽  
Author(s):  
Ronaldo de Carvalho Augusto ◽  
Aki Minoda ◽  
Oliver Rey ◽  
Céline Cosseau ◽  
Cristian Chaparro ◽  
...  
Keyword(s):  
Phenotypic Plasticity ◽  
Chromatin Structure ◽  
Environmental Gradients ◽  
Gene Mutations ◽  
Reaction Norms ◽  
Environmental Cues ◽  
Global Changes ◽  
Open Chromatin ◽  
Norm Of Reaction ◽  
Structure Changes

AbstractPhenotypic plasticity is an important feature of biological systems that is likely to play a major role in the future adaptation of organisms to the ongoing global changes. It may allow an organism to produce alternative phenotypes in responses to environmental cues. Modifications in the phenotype can be reversible but are sometimes enduring and can even span over generations. The notion of phenotypic plasticity was conceptualized in the early 20th century by Richard Woltereck. He introduced the idea that the combined relations of a phenotypic character and all environmental gradients that influence on it can be defined as “norm of reaction”. Norms of reaction are specific to species and to lineages within species, and they are heritable. He postulated that reaction norms can progressively be shifted over generations depending on the environmental conditions. One of his biological models was the water-flee daphnia. Woltereck proposed that enduring phenotypic modifications and gene mutations could have similar adaptive effects, and he postulated that their molecular bases would be different. Mutations occurred in genes, while enduring modifications were based on something he called the Matrix. He suggested that this matrix (i) was associated with the chromosomes, (ii) that it was heritable, (iii) it changed during development of the organisms, and (iv) that changes of the matrix could be simple chemical substitutions of an unknown, but probably polymeric molecule. We reasoned that the chromatin has all postulated features of this matrix and revisited Woltereck’s classical experiments with daphnia. We developed a robust and rapid ATAC-seq technique that allows for analyzing chromatin of individual daphnia and show here (i) that this technique can be used with minimal expertise in molecular biology, and (ii) we used it to identify open chromatin structure in daphnia exposed to different environmental cues. Our result indicates that chromatin structure changes consistently in daphnia upon this exposure confirming Woltereck’s classical postulate.

scholarly journals Microfluidic Platform for Analyzing the Thermotaxis of C. elegans in a Linear Temperature Gradient

2017 ◽  
Vol 33 (12) ◽  
pp. 1435-1440 ◽  
Author(s):  
Sunhee YOON ◽  
Hailing PIAO ◽  
Tae-Joon JEON ◽  
Sun Min KIM
Keyword(s):  
Temperature Gradient ◽  
Linear Temperature ◽  
Microfluidic Platform ◽  
C Elegans ◽  
Linear Temperature Gradient

scholarly journals Phenotypic plasticity can reverse the relative extent of intra- and interspecific variability across a thermal gradient

2021 ◽  
Vol 288 (1953) ◽  
pp. 20210428
Author(s):  
Staffan Jacob ◽  
Delphine Legrand
Keyword(s):  
Phenotypic Plasticity ◽  
Thermal Gradient ◽  
Environmental Gradients ◽  
Intraspecific Variability ◽  
Functional Trait ◽  
Ecosystem Functions ◽  
Interspecific Variability ◽  
Ciliate Species ◽  
Relative Extent ◽  
Trait Variability

Intra- and interspecific variability can both ensure ecosystem functions. Generalizing the effects of individual and species assemblages requires understanding how much within and between species trait variation is genetically based or results from phenotypic plasticity. Phenotypic plasticity can indeed lead to rapid and important changes of trait distributions, and in turn community functionality, depending on environmental conditions, which raises a crucial question: could phenotypic plasticity modify the relative importance of intra- and interspecific variability along environmental gradients? We quantified the fundamental niche of five genotypes in monocultures for each of five ciliate species along a wide thermal gradient in standardized conditions to assess the importance of phenotypic plasticity for the level of intraspecific variability compared to differences between species. We showed that phenotypic plasticity strongly influences trait variability and reverses the relative extent of intra- and interspecific variability along the thermal gradient. Our results show that phenotypic plasticity may lead to either increase or decrease of functional trait variability along environmental gradients, making intra- and interspecific variability highly dynamic components of ecological systems.

scholarly journals Do Differences in Latitudinal Distributions of Species and Organelle Haplotypes Reflect Thermal Reaction Norms Within the Emiliania/Gephyrocapsa Complex?

2021 ◽  
Vol 8 ◽  
Author(s):  
Peter von Dassow ◽  
Paula Valentina Muñoz Farías ◽  
Sarah Pinon ◽  
Esther Velasco-Senovilla ◽  
Simon Anguita-Salinas
Keyword(s):  
Local Adaptation ◽  
Coastal Upwelling ◽  
Environmental Gradients ◽  
Reaction Norm ◽  
Emiliania Huxleyi ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Thermal Niche ◽  
Significant Difference ◽  
The Difference

The cosmopolitan phytoplankter Emiliania huxleyi contrasts with its closest relatives that are restricted to narrower latitudinal bands, making it interesting for exploring how alternative outcomes in phytoplankton range distributions arise. Mitochondrial and chloroplast haplogroups within E. huxleyi are shared with their closest relatives: Some E. huxleyi share organelle haplogroups with Gephyrocapsa parvula and G. ericsonii which inhabit lower latitudes, while other E. huxleyi share organelle haplogroups with G. muellerae, which inhabit high latitudes. We investigated whether the phylogeny of E. huxleyi organelles reflects environmental gradients, focusing on the Southeast Pacific where the different haplogroups and species co-occur. There was a high congruence between mitochondrial and chloroplast haplogroups within E. huxleyi. Haplogroup II of E. huxleyi is negatively associated with cooler less saline waters, compared to haplogroup I, both when analyzed globally and across temporal variability at the small special scale of a center of coastal upwelling at 30° S. A new mitochondrial haplogroup Ib detected in coastal Chile was associated with warmer waters. In an experiment focused on inter-species comparisons, laboratory-determined thermal reaction norms were consistent with latitudinal/thermal distributions of species, with G. oceanica exhibiting warm thermal optima and tolerance and G. muellerae exhibiting cooler thermal optima and tolerances. Emiliania huxleyi haplogroups I and II tended to exhibit a wider thermal niche compared to the other Gephyrocapsa, but no differences among haplogroups within E. huxleyi were found. A second experiment, controlling for local adaptation and time in culture, found a significant difference between E. huxleyi haplogroups. The difference between I and II was of the expected sign, but not the difference between I and Ib. The differences were small (≤1°C) compared to differences reported previously within E. huxleyi by local adaptation and even in-culture evolution. Haplogroup Ib showed a narrower thermal niche. The cosmopolitanism of E. huxleyi might result from both wide-spread generalist phenotypes and specialist phenotypes, as well as a capacity for local adaptation. Thermal reaction norm differences can well explain the species distributions but poorly explain distributions among mitochondrial haplogroups within E. huxleyi. Perhaps organelle haplogroup distributions reflect historical rather than selective processes.

An Analytical Solution Countercurrent Heat Transfer Between Parallel Vessels With a Linear Axial Temperature Gradient

1988 ◽  
Vol 110 (3) ◽  
pp. 254-256 ◽  
Author(s):  
E. H. Wissler
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Heat Exchange ◽  
Temperature Gradient ◽  
Infinite Medium ◽  
Linear Temperature ◽  
Linear Temperature Gradient ◽  
Axial Temperature ◽  
Mixed Mean ◽  
The Difference

Presented in this paper is a solution for countercurrent heat exchange between two parallel vessels embedded in an infinite medium with a linear temperature gradient along the axes of the vessels. The velocity profile within the vessel is assumed to be parabolic. This solution describes the temperature field within the vessels, as well as in the tissue, and establishes that the intravessel temperature is not uniform, as is generally assumed to be the case. An explicit expression for the intervessel thermal resistance based on the difference between cup-mixed mean temperatures is derived.

Thermoregulatory control during pregnancy and lactation in rats

1997 ◽  
Vol 83 (3) ◽  
pp. 837-844 ◽  
Author(s):  
Heather L. Eliason ◽  
James E. Fewell
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Thermal Conductance ◽  
Thermoregulatory Response ◽  
Linear Temperature ◽  
Metabolic Chamber ◽  
Linear Temperature Gradient ◽  
Thermoneutral Zone ◽  
Pregnancy And Lactation ◽  
Near Term

Eliason, Heather L., and James E. Fewell.Thermoregulatory control during pregnancy and lactation in rats. J. Appl. Physiol. 83(3): 837–844, 1997.—Although the mechanisms remain unknown, maternal core temperature (Tc) decreases near term of pregnancy and is increased throughout lactation in rats. The purpose of our present experiments was to determine whether pregnancy and lactation shift the thermoneutral zone of rats and to investigate whether the changes in maternal Tcduring pregnancy and lactation result from “forced” or “regulated” thermoregulatory responses. Conscious, chronically instrumented nonpregnant and pregnant and lactating rats were studied both in a thermocline (a chamber with a linear temperature gradient from 12 to 36°C) and in a metabolic chamber to determine the influence of pregnancy and lactation on selected ambient temperature as well as the thermoregulatory response to changes in ambient temperature. We found that selected ambient temperature, oxygen consumption, and thermal conductance did not change in rats studied in a thermocline as Tc decreased near term of pregnancy. There was, however, a downward shift in the thermoneutral zone of rats studied in a metabolic chamber near term of pregnancy. During lactation, selected ambient temperature decreased in rats studied in a thermocline as oxygen consumption and Tc increased. The thermoneutral zone of lactating rats was not different from that of nonpregnant animals. Thus our data provide evidence that the decrease in Tc near term of pregnancy in rats results from a regulated thermoregulatory response, whereas the increase in Tc during lactation results from a forced thermoregulatory response.

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