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

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

Abundance, efficiency, and stability of reference transcript expression in a seasonal rodent: The Siberian hamster

Quantitative PCR (qPCR) is a common molecular tool to analyse the expression of transcripts in non-traditional animal models. Most animals experience tissue-specific seasonal changes in cell structure, growth, and cellular function. As a consequence, the choice of reference or ‘house-keeping’ genes is essential to standardize expression levels of target transcripts of interest for qPCR analyses. This study aimed to determine the abundance, efficiency and stability of several reference genes commonly used for normalisation of qPCR analyses in a model of seasonal biology: the Siberian hamster (Phodopus sungorus). Liver, brown-adipose tissue (BAT), white adipose tissue (WAT), testes, spleen, kidney, the hypothalamic arcuate nucleus, and the pituitary gland from either long or short photoperiod Siberian hamsters were dissected to test tissue-specific and photoperiod effects on reference transcripts. qPCR was conducted for common reference genes including 18s ribosomal RNA (18s), glyceraldehyde 3-phosphate dehydrogenase (Gapdh), hypoxanthine-guanine phosphoribosyltransferase (Hprt), and actin-β (Act). Cycling time (Ct), efficiency (E) and replicate variation of Ct and E measured by percent coefficient of variance (CV%) was determined using PCR miner. Measures of stability were assessed using a combined approach of NormFinder and BestKeeper. 18s and Act did not vary in Ct across photoperiod conditions. Splenic, WAT and BAT Gapdh Ct was higher in long compared to short photoperiod. Splenic Hprt Ct was higher in long photoperiods. There was no significant effect of photoperiod, tissue or interaction on measures of efficiency, Ct CV%, or efficiency CV%. NormFinder and BestKeeper confirmed that 18s, Gapdh and Hprt were highly stable, while Act showed low stability. These findings suggest that 18s and Hprt show the most reliable stability, efficiency, and abundance across the tissues. Overall, the study provides a comprehensive and standardised approach to assess multiple reference genes in the Siberian hamster and help to inform molecular assays used in studies of photoperiodism

Cyclical DNA Methyltransferase 3a Expression Is a Seasonal and Estrus Timer in Reproductive Tissues

Acknowledgments We thank Gerald Lincoln for his critical feedback on a previous version of this manuscript. Author contributions included the following: T.J.S. conceived the project, designed the experiments, analyzed the data, and wrote the manuscript. E.W.J.L. conducted the experiments and analyzed the data. C.S.C. conducted the immunocytochemistry. M.L. conducted the HEK293 cell culture assays. E.M.C. and A.S.B. provided technical assistance. This work was supported by the University of Aberdeen College of Life Sciences and Medicine grant (to T.J.S.). E.W.J.L. was supported by a Society for Reproduction and Fertility undergraduate scholarship. Disclosure Summary: The authors have nothing to disclose.Peer reviewedPostprin