Epigenetic Regulation of Biological Rhythms : An Evolutionary Ancient Molecular Timer

The author thanks Barbara Helm, John O’Neill and Brian Prendergast for constructive comments on a previous version of the manuscript.Peer reviewedPostprin

Circannual and circadian rhythms of hypothalamic DNA methyltransferase and histone deacetylase expression in male Siberian hamsters (Phodopus sungorus)

Acknowledgements TJS was funded by a College of Life Sciences and Medicine start-up award from the University of Aberdeen. TJS thanks Betty Theriault for expert veterinary care and Kenneth Onishi for technical assistance. TJS would like to express his sincere gratitude and appreciation to Brian Prendergast for intellectual support, constructive discussions and critical evaluation of the present study.Peer reviewedPostprin

Appetitive information seeking behaviour reveals robust daily rhythmicity for Internet-based food-related keyword searches

Funding We received no funding for this study. Acknowledgement We thank the feedback from participants of The Association for the Study of Animal Behaviour Easter 2017 conference, where the work was presented. Electronic supplementary material is available online at https://doi.org/10.6084/m9.figshare.c.4174325. The data are freely available online in Google Trends (www.google.co.uk/trends/).Peer reviewedPublisher PD

Defining the brain control of physiological stability

The last few decades have seen major advances in neurobiology and uncovered novel genetic and cellular substrates involved in the control of physiological set points. In this Review, I discuss the limitations in the definition of homeostatic set points established by Walter B Canon and highlight evidence that two other physiological systems, namely rheostasis and allostasis provide distinct inputs to independently modify set-point levels. Using data collected over the past decade, the hypothalamic and genetic basis of regulated changes in set-point values by rheostatic mechanisms are described. Then, the role of higher-order brain regions, such as hippocampal circuits, for experience-dependent, allostatic induced changes in set-points are outlined. I propose that these systems provide a hierarchical organization of physiological stability that exists to maintain set-point values. The hierarchical organization of physiology has direct implications for basic and medical research, and clinical practice

The Value of Comparative Animal Research : Krogh’s Principle Facilitates Scientific Discoveries

There are no conflicts of interest to declare. This paper developed from the 2016 Early Career Impact Award from the Federation of Associations in Behavioral & Brain Sciences to TJS. TJS has received funding from The Leverhulme Trust. FJPE is in receipt of funding from the BBSRC (BB/M001555/1). The National Institutes of Health has funded RDF (NS 034950, NS093277, NIMH 087930), AGO (HD079573, IOS-1354760) and AMK (HD081959). BAA is an Arnold O. Beckman postdoctoral fellow.Peer reviewedPostprin

Maternal developmental history alters transfer of circadian clock genes to offspring in Japanese quail (Coturnix japonica)

Funding: This work was supported by the UKRI Biotechnology and Biological Sciences Research Council (BBSRC) Eastbio Doctoral Training Programme grant number BB/M010996/1.Maternal signals shape embryonic development, and in turn post-natal phenotypes. RNA deposition is one such method of maternal signalling and circadian rhythms are one trait thought to be maternally inherited, through this mechanism. These maternal circadian gene transcripts aid development of a functioning circadian system. There is increasing evidence that maternal signals can be modified, depending on prevailing environmental conditions to optimise offspring fitness. However, currently, it is unknown if maternal circadian gene transcripts, and consequently early embryonic gene transcription, are altered by maternal developmental conditions. Here, using avian mothers who experienced either pre-natal corticosterone exposure, and/or post-natal stress as juveniles we were able to determine the effects of the timing of stress on downstream circadian RNA deposition in offspring. We demonstrated that maternal developmental history does indeed affect transfer of offspring circadian genes, but the timing of stress was important. Avian mothers who experienced stress during the first 2 weeks of post-natal life increased maternally deposited transcript levels of two core circadian clock genes, BMAL1 and PER2. These differences in transcript levels were transient and disappeared at the point of embryonic genome transcription. Pre-natal maternal stress alone was found to elicit delayed changes in circadian gene expression. After activation of the embryonic genome, both BMAL1 and PER2 expression were significantly decreased. If both pre-natal and post-natal stress occurred, then initial maternal transcript levels of BMAL1 were significantly increased. Taken together, these results suggest that developmental stress differentially produces persistent transgenerational effects on offspring circadian genes.Publisher PDFPeer reviewe

Digital Epidemiology Reveals Global Childhood Disease Seasonality and the Effects of Immunization

ACKNOWLEDGMENTS. We would like to thank Fernando Gonzalez-Dominguez and Gilberto Vaughan for providing the chicken pox case reports from Mexico, and the Estonia Health Board, Department of Communicable Disease Surveillance and Control, for Estonian chicken pox case reports. KB would like to thank Mercedes Pascual, her lab, and Marisa Eisenberg for helpful comments. Jesus Cantu (research assistant, Princeton University) translated and categorized chicken pox searches from Mexico, Thailand, Australia, and the US.Peer reviewedPostprintPostprin

Pre-natal exposure to glucocorticoids causes changes in developmental circadian clock gene expression and post-natal behaviour in the Japanese quail

Funding: JLH was funded by UKRI Biotechnology and Biological Sciences Research Council (BBSRC) Eastbio Doctoral Training Programme grant number BB/M010996/1. KAS was funded by BBSRC grant (BB/ R003777/1). TJS was funded by the Leverhulme Trust. LFB was funded by the Swedish Research Council (Vetenskapsrådet: 2021-05466).The embryonic environment is critical in shaping developmental trajectories and consequently post-natal phenotypes. Exposure to elevated stress hormones during this developmental stage is known to alter a variety of post-natal phenotypic traits, and it has been suggested that pre-natal stress can have long term effects on the circadian rhythm of glucocorticoid hormone production. Despite the importance of the circadian system, the potential impact of developmental glucocorticoid exposure on circadian clock genes, has not yet been fully explored. Here, we showed that pre-natal exposure to corticosterone (CORT, a key glucocorticoid) resulted in a significant upregulation of two key hypothalamic circadian clock genes during the embryonic period in the Japanese quail (Coturnix japonica). Altered expression was still present 10 days into post-natal life for both genes, but then disappeared by post-natal day 28. At post-natal day 28, however, diel rhythms of eating and resting were influenced by exposure to pre-natal CORT. Males exposed to pre-natal CORT featured an earlier acrophase, alongside spending a higher proportion of time feeding. Females exposed to pre-natal CORT featured a less pronounced shift in acrophase and spent less time eating. Both males and females exposed to pre-natal CORT spent less time inactive during the day. Pre-natal CORT males appeared to feature a delay in peak activity levels. Our novel data suggest that these circadian clock genes and aspects of diurnal behaviours are highly susceptible to glucocorticoid disruption during embryonic development, and these effects are persistent across developmental stages, at least into early post-natal life.Peer reviewe