Relocalization of an 82-kDa protein from lampbrush loops into the nucleoskeleton during amphibian oogenesis

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An analog of Xenopus N1N2 protein in Pleurodeles waltl

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The behavioural and physiological stress responses are linked to plumage coloration in the rock pigeon ( Columbia livia )

International audienceIn wild vertebrates, conspicuousness often signals a high phenotypic quality and is therefore associated with fitness benefits (“the handicap principle hypothesis”). However, conspicuous individuals usually face a higher risk of predation because they are easier to detect. Therefore, conspicuous individuals are expected to modify their behavioural and their physio logical stress responses to limit the negative effect of their conspicuousness on survival. We examined the link between plumage coloration and the stress response in a bird species (the rock pigeon, Columbia livia) by comparing two groups of pigeons with different plumage characteristics: ‘blue-bar’ birds (lighter birds) and ‘checker’ birds (darker birds). Specifically, we measured several behavioural and physiological components of the stress response (breath rate, corticosterone, and tonic immobility). Although breath rate did not differ between ‘checker’ and ‘blue bar’ birds, the corticosterone stress response of ‘blue-bar’ birds was greater relative to that of ‘checker’ birds. Moreover, ‘checker’ birds were more likely to initiate tonic immobility relative to ‘blue bar’ birds. Therefore, this study suggests that the behavioural and physiological stress responses of wild birds may differ according to their plumage coloration. To conclude, our results suggest that plumage colorations may be functionally linked to specific behavioral and physiological sensitivities to stressors

Endocrine consequences of an acute stress under different thermal conditions: a study of corticosterone, prolactin, and thyroid hormones in the pigeon (Columbia livia)

International audienceIn the context of global change, the physiological and hormonal stress responses have received much attentionbecause of their implications in terms of allostasis. However, most studies have focused on glucocorticoidsonly as the “common” response to stressorswhile neglecting other endocrine axes and hormones (e.g. prolactin,thyroid hormones) that play a crucial role in metabolic adjustments. Interestingly, the responsiveness of all theseendocrine axes to stress may depend on the energetic context and this context-dependent stress response hasbeen overlooked so far. In the wild, temperature can vary to a large extent within a short time window and ambienttemperature may affect these metabolic-related endocrine axes, and potentially, their responsiveness to anacute stressor. Here,we explicitly tested this hypothesis by examining the effect of a standardized stress protocolon multiple hormonal responses in the rock pigeon (Columbia livia). We tested the effect of an acute restraintstress on (1) corticosterone levels, (2) prolactin levels, and (3) thyroid hormone levels (triiodothyronine,thyroxine) in pigeons that were held either at cool temperature (experimental birds) or at room temperature(control birds) during the stress protocol. Although we found a significant influence of restraint stress on mosthormone levels (corticosterone, prolactin, and thyroxine), triiodothyronine levels were not affected by the restraintstress. This demonstrates that stressors can have significant impact on multiple endocrine mechanisms.Importantly, all of these hormonal responses to stress were not affected by temperature, demonstrating thatthe exposure to cold temperature does not affect the way these hormone levels change in response to handlingstress. This suggests that some endocrine responses to temperature decreases may be overridden by the endocrineresponses to an acute restraint stress

Cold-induced changes in amphibian oocytes.

International audienceFemale Pleurodeles waltl newts (Amphibia, urodele), usually raised at 20 degrees C, were submitted to low temperatures; oocytes responded to this cold stress by drastic changes both in lampbrush chromosome structure and in protein pattern. Preexisting lateral loops of lampbrush chromosomes were reduced in size and number, while cold-induced loops which were tremendously developed, occurred on defined bivalents of the oocyte at constant, reproducible sites. A comparison of protein patterns in control and stressed oocytes showed two main differences: in stressed oocytes, overall protein synthesis was reduced, except for a set of polypeptides, the "cold-stress proteins"; second, there was a striking inversion of the relative amount of beta- and gamma-actin found in the oocyte nucleus before and after cold stress. Whereas beta-actin was the predominant form in control oocytes, gamma-actin became the major form in stressed oocytes

ESM1 from "Does the stress response predict the ability of wild birds to adjust to short-term captivity? A study in the rock pigeon (Columbia livia)" by Frédéric Angelier, Charline Parenteau, Colette Trouvé, Nicole Angelier. This table present the data that were used for this article from Does the stress response predict the ability of wild birds to adjust to short-term captivity? A study in the rock pigeon (<i>Columbia livia</i>)

Although the transfer of wild animals to captivity is crucial for conservation purposes, this process is often challenging, because some species or individuals do not adjust well to captive conditions. Chronic stress has been identified as a major concern for animals held on long-term captivity. Surprisingly, the first hours or days of captivity have been relatively overlooked. However, they are certainly very stressful, because individuals are being transferred to a totally novel and confined environment. To ensure the success of conservation programmes, it appears crucial to better understand the proximate causes of interspecific and interindividual variability in the sensitivity to these first hours of captivity. In that respect, the study of stress hormones is relevant, because the hormonal stress response may help to assess whether specific individuals or species adjust, or not, to such captive conditions (‘the stress response-adjustment to captivity hypothesis’). We tested this hypothesis in rock pigeons by measuring their corticosterone stress response and their ability to adjust to short-term captivity (body mass loss and circulating corticosterone levels after a day of captivity). We showed that an increased corticosterone stress response is associated with a lower ability to adjust to short-term captivity (i.e. higher body mass loss and circulating corticosterone levels). Our study suggests, therefore, that a low physiological sensitivity to stress may be beneficial for adjusting to captivity. Future studies should now explore whether the stress response can be useful to predict the ability of individuals from different populations or species to not only adjust to short-term, but also long-term captivity

ESM2 from "Does the stress response predict the ability of wild birds to adjust to short-term captivity? A study in the rock pigeon (Columbia livia)" by Frédéric Angelier, Charline Parenteau, Colette Trouvé, Nicole Angelier. This analysis and thisfigure present the influence of a week of captivity on daily body mass of rock pigeons. from Does the stress response predict the ability of wild birds to adjust to short-term captivity? A study in the rock pigeon (<i>Columbia livia</i>)

Although the transfer of wild animals to captivity is crucial for conservation purposes, this process is often challenging, because some species or individuals do not adjust well to captive conditions. Chronic stress has been identified as a major concern for animals held on long-term captivity. Surprisingly, the first hours or days of captivity have been relatively overlooked. However, they are certainly very stressful, because individuals are being transferred to a totally novel and confined environment. To ensure the success of conservation programmes, it appears crucial to better understand the proximate causes of interspecific and interindividual variability in the sensitivity to these first hours of captivity. In that respect, the study of stress hormones is relevant, because the hormonal stress response may help to assess whether specific individuals or species adjust, or not, to such captive conditions (‘the stress response-adjustment to captivity hypothesis’). We tested this hypothesis in rock pigeons by measuring their corticosterone stress response and their ability to adjust to short-term captivity (body mass loss and circulating corticosterone levels after a day of captivity). We showed that an increased corticosterone stress response is associated with a lower ability to adjust to short-term captivity (i.e. higher body mass loss and circulating corticosterone levels). Our study suggests, therefore, that a low physiological sensitivity to stress may be beneficial for adjusting to captivity. Future studies should now explore whether the stress response can be useful to predict the ability of individuals from different populations or species to not only adjust to short-term, but also long-term captivity

Time-lapse Microscopy and Fluorescence Resonance Energy Transfer to Analyze the Dynamics and Interactions of Nucleolar Proteins in Living Cells.

International audienceThe dynamics of proteins play a key role in the organization and control of nuclear functions. Techniques were developed recently to observe the movement and interactions of proteins in living cells; time-lapse microscopy using fluorescent-tagged proteins gives access to observations of nuclear protein trafficking over time, and fluorescence resonance energy transfer (FRET) is used to investigate protein interactions in the time-lapse mode. In this chapter, we describe the application of these two approaches to follow the recruitment of nucleolar processing proteins at the time of nucleolar assembly. We question the role of prenucleolar bodies (PNB) during migration of the processing proteins from the chromosome periphery to sites of ribosomal genes (rDNA) transcription. The order of recruitment of different processing proteins into nucleoli is the consequence of differential sorting from the same PNBs. The dynamics of the interactions between processing proteins in PNBs suggest that PNBs are preassembly platforms for ribosomal RNA (rRNA) processing complexes