656 research outputs found
Book Review: Die Bram Fischer Wals
No full textBook Title: Die Bram Fischer WalsBook Author: Harry Kalmer Johannesburg: Wits University Press, 2016. 67pp. ISBN 978-1-77614-005-3
Transition between fermentation and respiration determines history-dependent behavior in fluctuating carbon sources
No full textCells constantly adapt to environmental fluctuations. These physiological changes require time and therefore cause a lag phase during which the cells do not function optimally. Interestingly, past exposure to an environmental condition can shorten the time needed to adapt when the condition re-occurs, even in daughter cells that never directly encountered the initial condition. Here, we use the molecular toolbox of Saccharomyces cerevisiae to systematically unravel the molecular mechanism underlying such history-dependent behavior in transitions between glucose and maltose. In contrast to previous hypotheses, the behavior does not depend on persistence of proteins involved in metabolism of a specific sugar. Instead, presence of glucose induces a gradual decline in the cells' ability to activate respiration, which is needed to metabolize alternative carbon sources. These results reveal how trans-generational transitions in central carbon metabolism generate history-dependent behavior in yeast, and provide a mechanistic framework for similar phenomena in other cell types.sponsorship: Fonds Wetenschappelijk Onderzoek Bram Cerulus Lieselotte Vermeerschr Vlaams Instituut voor Biotechnologie Kevin J Verstrepenr European Research Council CoG682009 Bram Cerulus Abbas Jariani Gemma Perez-Samper Kevin J Verstrepenr AB-InBev-Baillet Latour Fund Kevin J Verstrepenr Human Frontier Science Program 246 RGP0050/2013 Abbas Jariani Peter S Swain Kevin J Verstrepenr SULSA Postdoctoral Exchange Scheme Julian M J Pietschr The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. (Fonds Wetenschappelijk Onderzoek, Vlaams Instituut voor Biotechnologie, European Research Council|CoG682009, AB-InBev-Baillet Latour Fund, SULSA Postdoctoral Exchange Scheme, Human Frontier Science Program|246 RGP0050/2013)status: Publishe
Fenotypische variatie en cellulair geheugen van Saccharomyces cerevisiae in stabiele en veranderende suikeromgevingen
No full textThe field of microbiology has long ignored differences between cells within clonal populations. This is at least partly because technical limitations prevented measuring parameters of individual cells. However, the development of single-cell based techniques has revealed that even within clonal populations in a homogeneous environment, a substantial heterogeneity exists between individual cells. This phenomenon is broadly known as phenotypic heterogeneity, or noise. In addition, it became evident that individual cells have the capacity to remember certain environmental signals, which in some cases can increase the adaptation rate when a similar environment returns. This phenomenon is known as cellular or epigenetic memory.
In general, the observation of phenotypic heterogeneity and cellular memory generates two central questions. First, are these phenomena beneficial or harmful to the organism’s fitness? And second, which molecular mechanisms determine or affect these traits? Here, we try to partially answer these questions, using Saccharomyces cerevisiae during growth in stable and fluctuating sugar environments as a model system.
In the first chapter, we address the former question by studying how noise and cellular memory in single-cell division times affects the organism’s fitness. First, using time-lapse microscopy, we analyze the single-cell growth behavior of a variety of genetically distinct yeast populations. We find large differences in individual division times and substantial epigenetic inheritance of division times within mother-daughter lineages. Next, we develop a stochastic model with single-cell parameters based on these measurements to accurately predict population-level growth. Briefly, we find that, for a given mean division time, increasing heterogeneity and epigenetic inheritance of division times increases the population growth rate. In the second chapter, we address the latter question of how we can mechanistically explain the traits of noise and cellular memory. More specifically, we investigate the molecular mechanism that underlies cellular memory in the switch from glucose to maltose in yeast. Using a combination of single-cell measurements and genome-wide screens, we show that in contrast to what has been reported in other cases, the memory is not linked to cytoplasmic inheritance of Mal proteins during glucose growth. Instead, we propose that, in this case, a gradual transition between respiratory and fermentative metabolism causes cellular memory. Taken together, our results show that noise and epigenetic inheritance of division times have the potential to increase population growth rate during exponential growth, and that unexpectedly, cellular memory during growth in fluctuating sugar environments can be determined by a metabolic re-arrangement taking place in central carbon metabolism.status: Publishe
Bram Stoker and the stage: reviews, reminiscences, essays and fiction
No full textThough best known as the author of Dracula (1897) Bram Stoker had a successful career in the theatre. This collection brings together all Stoker’s theatrical reviews from Dublin’s Evening Mail, his published essays and interviews on the theatre, selections from Reminiscences of Henry Irving (1906) and a fictional work on the theatre
A new protocol for single-cell RNA-seq reveals stochastic gene expression during lag phase in budding yeast
No full textCurrent methods for single-cell RNA sequencing (scRNA-seq) of yeast cells do not match the throughput and relative simplicity of the state-of-the-art techniques that are available for mammalian cells. In this study, we report how 10x Genomics' droplet-based single-cell RNA sequencing technology can be modified to allow analysis of yeast cells. The protocol, which is based on in-droplet spheroplasting of the cells, yields an order-of-magnitude higher throughput in comparison to existing methods. After extensive validation of the method, we demonstrate its use by studying the dynamics of the response of isogenic yeast populations to a shift in carbon source, revealing the heterogeneity and underlying molecular processes during this shift. The method we describe opens new avenues for studies focusing on yeast cells, as well as other cells with a degradable cell wall.sponsorship: Fonds Wetenschappelijk Onderzoek Lieselotte Vermeersch Bram Cerulus Karin VoordeckersVlaams Instituut voor Biotechnologie Kevin J VerstrepenEuropean Research Council Council CoG682009 Kevin J VerstrepenAB-InBev-Baillet Latour Fund Kevin J VerstrepenHuman Frontier Science Program 246 RGP0050/2013 Kevin J VerstrepenThe funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. (Fonds Wetenschappelijk Onderzoek, Vlaams Instituut voor Biotechnologie, European Research Council|CoG682009, AB-InBev-Baillet Latour Fund, Human Frontier Science Program|246 RGP0050/2013)status: Publishe
GHOSTS FROM THE PAST! or, BRAM STOKER'S ARMADA
No full texthttps://www.euronewsproject.org/2022/07/08/ghosts-from-the-past-or-bram-stokers-armada/
Who has not heard of Dracula, gothic classic of vampire lore par excellence? What about The Mystery of the Sea? The latter book by the same author received far less acclaim. To be sure, books were not this Irish author’s only stock in trade. By the time Bram Stoker published his famous work he was already nearing the end of a long mostly unrelated career in theater promotion and management which had brought him in contact with English as well as American high society. As a writer, his experience also included theater reviews for a Dublin newspaper. Arguably, all these aspects, and much else besides, find their way somehow into the novels; but that is not our concern here
Bram Stoker: history, psychoanalysis, and the Gothic
No full textBram Stoker is best remembered today as the author of Dracula. However, this Dublin-born Anglo-Irishman combined a writing career which produced eleven novels and a wealth of short stories, biography and journalism, with a full-time occupation as a theatre manager and society figure in fin de siecle London.
This volume testifies to the breadth and diversity of Stoker's writings and interests, and reassesses the significant contribution which the author made to the Gothic tradition. Its Introduction analyses the reasons behind Stoker's exclusion from the literary canon through an exploration of the changes in critical and cultural studies in the late twentieth century. The twelve critical essays which follow, each written by an acknowledged expert in the field, demonstrate a variety of critical approaches to Stoker and to the ideas and problems presented by his writings before and after Dracula
Correction to: The ‘can do, do do’ concept in COPD; quadrant interpretation, affiliation and tracking longitudinal changes
No full textFollowing publication of the original article [1], the authors identified a mistake in the author names, as both forename and initials were stated. Initially published author names: A. J. Alex van ’t Hul, E. H. Noortje Koolen, H. W. Jeroen van Hees, B. Bram van den Borst and M. A. Martijn Spruit Correct author names: Alex J. van ‘t Hul, Noortje H. Koolen, Jeroen W. van Hees, Bram van den Borst, Martijn A. Spruit. The original article has been corrected.</p
"The curse of Ireland in our own time": Bram Stoker and the stage Irishman
No full textBram Stoker (1847–1912), famous as the author of 'Dracula', was born in Dublin. He was Sir Henry Irving’s secretary and touring manager for 27 years. A Protestant and a Liberal, Stoker believed in Home Rule for Ireland but was also a monarchist, a believer in Empire and an admirer of Gladstone. The speaker will discuss in detail Stoker’s complex attitudes to Ireland
The impact of strategy on supply chain and forecasting
No full textIn this provocative article, Bram Desmet explores how a company's market strategy affects its supply chain targets and forecasting methodology. The author introduces the concept of the supply chain triangle to illustrate the balancing act a company must perform to achieve the cost, service, and inventory mix that maximizes its return on capital employed. He then shows how the company's strategic choice, be it operational excellence, product leadership, or customer intimacy, influences the position it seeks on the supply chain triangle and, in particular, its inventory target
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