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1. Effect of temperature on the Arabidopsis cryptochrome photocycle

   https://doi.org/10.1111/ppl.13365  

   Pooam, Marootpong; Dixon, Nykiera; Hilvert, Michael; Misko, Peter; Waters, Kristy; Jourdan, Nathalie; Drahy, Soria; Mills, Stephen; Engle, Dorothy; Link, Justin; et al (March 2021, Physiologia Plantarum)

   Abstract Cryptochromes are blue light‐absorbing photoreceptors found in plants and animals with many important signalling functions. These include control of plant growth, development, and the entrainment of the circadian clock. Plant cryptochromes have recently been implicated in adaptations to temperature variation, including temperature compensation of the circadian clock. However, the effect of temperature directly on the photochemical properties of the cryptochrome photoreceptor remains unknown. Here we show that the response to light of purifiedArabidopsisCry1 and Cry2 proteins was significantly altered by temperature. Spectral analysis at 15°C showed a pronounced decrease in flavin reoxidation rates from the biologically active, light‐induced (FADH°) signalling state of cryptochrome to the inactive (FADox) resting redox state as compared to ambient (25°C) temperature. This result indicates that at low temperatures, the concentration of the biologically active FADH° redox form of Cry is increased,leading to the counterintuitive prediction that there should be an increased biological activity of Cry at lower temperatures. This was confirmed using Cry1 cryptochrome C‐terminal phosphorylation as a direct biological assay for Cry activationin vivo. We conclude that enhanced cryptochrome functionin vivoat low temperature is consistent with modulation by temperature of the cryptochrome photocycle. 

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2. Temperature affects the repeatability of evolution in the microbial eukaryote Tetrahymena thermophila

   https://doi.org/10.1002/ece3.8036  

   Tarkington, Jason; Zufall, Rebecca A. (August 2021, Ecology and Evolution)

   Abstract Evolutionary biologists have long sought to understand what factors affect the repeatability of adaptive outcomes. To better understand the role of temperature in determining the repeatability of adaptive trajectories, we evolved populations of different genotypes of the ciliateTetrahymena thermophilaat low and high temperatures and followed changes in growth rate over 6,500 generations. As expected, growth rate increased with a decelerating rate for all populations; however, there were differences in the patterns of evolution at the two temperatures. The growth rates of the different genotypes tended to converge as evolution proceeded at both temperatures, but this convergence was quicker and more pronounced at the higher temperature. Additionally, over the first 4,000 generations we found greater repeatability of evolution, in terms of change in growth rate, among replicates of the same genotype at the higher temperature. Finally, we found limited evidence of trade‐offs in fitness between temperatures, and an asymmetry in the correlated responses, whereby evolution in a high temperature increases growth rate at the lower temperature significantly more than the reverse. These results demonstrate the importance of temperature in determining the repeatability of evolutionary trajectories for the eukaryotic microbeTetrahymena thermophilaand may provide clues to how temperature affects evolution more generally. 

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3. ALMA characterizes the dust temperature of z ∼ 5.5 star-forming galaxies

   https://doi.org/10.1093/mnras/staa2545  

   Faisst, Andreas L; Fudamoto, Yoshinobu; Oesch, Pascal A; Scoville, Nick; Riechers, Dominik A; Pavesi, Riccardo; Capak, Peter (September 2020, Monthly Notices of the Royal Astronomical Society)

   ABSTRACT The infrared (IR) spectral energy distributions (SEDs) of main-sequence galaxies in the early Universe (z > 4) is currently unconstrained as IR continuum observations are time-consuming and not feasible for large samples. We present Atacama Large Millimetre Array Band 8 observations of four main-sequence galaxies at z ∼ 5.5 to study their IR SED shape in detail. Our continuum data (rest-frame 110 $$\rm \mu m$$, close to the peak of IR emission) allows us to constrain luminosity-weighted dust temperatures and total IR luminosities. With data at longer wavelengths, we measure for the first time the emissivity index at these redshifts to provide more robust estimates of molecular gas masses based on dust continuum. The Band 8 observations of three out of four galaxies can only be reconciled with optically thin emission redward of rest-frame $$100\, {\rm \mu m}$$. The derived dust peak temperatures at z ∼ 5.5 ($$30\!-\!43\, {\rm K}$$) are elevated compared to average local galaxies, however, $$\sim 10\, {\rm K}$$ below what would be predicted from an extrapolation of the trend at z < 4. This behaviour can be explained by decreasing dust abundance (or density) towards high redshifts, which would cause the IR SED at the peak to be more optically thin, making hot dust more visible to the external observer. From the $$850{\hbox{-}}{\rm \mu m}$$ dust continuum, we derive molecular gas masses between 1010 and $$10^{11}\, {\rm M_{\odot }}$$ and gas fractions (gas over total mass) of $$30\!-\!80{{\ \rm per\ cent}}$$ (gas depletion times of $$100\!-\!220\, {\rm Myr}$$). All in all, our results provide a first measured benchmark SED to interpret future millimetre observations of normal, main-sequence galaxies in the early Universe. 

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4. Transcriptomic signatures of temperature adaptation in the eastern oyster Crassostrea virginica

   https://doi.org/10.1111/jeb.13789  

   Johnson, Kevin M.; Jones, Hollis R.; Casas, Sandra M.; La Peyre, Jerome F.; Kelly, Morgan W. (July 2021, Journal of Evolutionary Biology)

   Abstract The large geographic distribution of the eastern oyster,Crassostrea virginica,makes it an ideal species to test how populations have adapted to latitudinal gradients in temperature. Despite inhabiting distinct thermal regimes, populations ofC. virginicanear the species’ southern and northern geographic range show no population differences in their physiological response to temperature. In this study, we used comparative transcriptomics to understand how oysters from either end of the species’ range maintain enantiostasis across three acclimation temperatures (10, 20, and 30°C). With this approach, we identified genes that were differentially expressed in response to temperature between individuals ofC. virginicacollected from New Brunswick, Canada and Louisiana, USA. We observed a core set of genes whose expression responded to temperature in both populations, but also an even larger set of genes with expression patterns that were unique to each population. Intriguingly, the genes with population‐specific responses to temperature had elevatedF_STand Ka/Ks ratios compared to the genome‐wide average. In contrast, genes showing only a response to temperature were found to only have elevatedF_STvalues suggesting that divergentF_STmay be due to selection on linked regulatory regions rather than positive selection on protein coding regions. Taken together, our results suggest that, despite coarse‐scale physiological similarities, natural selection has shaped divergent gene expression responses to temperature in geographically separated populations of this broadly eurythermal marine invertebrate. 

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5. The Role of Temperature in the Distribution of the Glacier Ice Worm, Mesenchytraeus solifugus (Annelida: Oligochaeta: Enchytraeidae)

   https://doi.org/10.1657/AAAR0015-042  

   Dial, Roman J.; Becker, Melissa; Hope, Andrew G.; Dial, Cody R.; Thomas, Joseph; Slobodenko, Katarina A.; Golden, Trevor S.; Shain, Daniel H. (February 2016, Arctic, Antarctic, and Alpine Research)