The cucumber tendril — a new test organ for gibberellic acid

Résumé On peut se servir de tronçons de vrilles de concombre en voie de dévelopmentin vitro, pour déterminer d'après leurs réactions la présence d'acide gibberellique (GA). L'avantage de cette méthode réside dans le fait qu'on peut l'employer en la combinant avec la chromatographie sur papier et ainsi évaluer le GA dans l'extrait des plantes.     

Does color discrimination in pigeons vary as a function of retinal localizagion?]

Color discrimination in the red portion of the visual spectrum was studied for different retinal locations under "behavioural" fixation. In spite of the different distribution of coloured oil-droplets, the discrimination function remains the same.     

The peritoneal “soil” for a cancerous “seed”: a comprehensive review of the pathogenesis of intraperitoneal cancer metastases

Various types of tumors, particularly those originating from the ovary and gastrointestinal tract, display a strong predilection for the peritoneal cavity as the site of metastasis. The intraperitoneal spread of a malignancy is orchestrated by a reciprocal interplay between invading cancer cells and resident normal peritoneal cells. In this review, we address the current state-of-art regarding colonization of the peritoneal cavity by ovarian, colorectal, pancreatic, and gastric tumors. Particular attention is paid to the pro-tumoral role of various kinds of peritoneal cells, including mesothelial cells, fibroblasts, adipocytes, macrophages, the vascular endothelium, and hospicells. Anatomo-histological considerations on the pro-metastatic environment of the peritoneal cavity are presented in the broader context of organ-specific development of distal metastases in accordance with Paget’s “seed and soil” theory of tumorigenesis. The activity of normal peritoneal cells during pivotal elements of cancer progression, i.e., adhesion, migration, invasion, proliferation, EMT, and angiogenesis, is discussed from the perspective of well-defined general knowledge on a hospitable tumor microenvironment created by the cellular elements of reactive stroma, such as cancer-associated fibroblasts and macrophages. Finally, the paper addresses the unique features of the peritoneal cavity that predispose this body compartment to be a niche for cancer metastases, presents issues that are topics of an ongoing debate, and points to areas that still require further in-depth investigations.     

The story of ‘Scientist: The Story of a Word’

This examination of an important paper by Sydney Ross is the first in a projected series of occasional reflections on ‘Annals of Science Classic Papers’ that have had enduring utility within the field of history of science and beyond. First the messages of the paper are examined, some well known but others, particularly Ross's own contemporary concerns about the use of the word ‘scientist’, less so. The varied uses made of the paper by scholars are then traced before Ross's biography is examined in order to try to understand how a figure professionally marginal to the field of history of science came to write such a significant piece. Ross’s interest in the topic appears to have been informed by a romantically tinged scientific progressivism and a deep concern with the importance of linguistic precision in science and in public affairs. The inspirations of the author and the interests of his audience have been only partially aligned, but the paper's insights remain of broad historical interest and have wider ramifications since the denotation ‘scientist’ and its proper application are much debated today in contests over the authority of science.     

The urokinase receptor: a ligand or a receptor? Story of a sociable molecule

In this last decade, the structure and functions of the receptor for the urokinase-type plasminogen activator have been extensively studied and characterized. This interesting receptor plays a key role in cell adhesion, migration and proliferation. It was identified 20 years ago as the specific cell-surface molecule that could bind and concentrate urokinase on the cell membrane, thus initiating the proteolytic cascade promoted by the activation of plasminogen. The identification of new extracellular ligands, such as vitronectin, and of cell-surface interactors, such as integrins and fMet-Leu-Phe receptors, shed new light on its possible roles, totally independent of the enzymatic properties of its ligand. uPAR ligands and interactors and the functional consequences of the multiple binding capability of this intriguing receptor are reviewed here. Received 19 September 2005; received after revision 4 December 2005; accepted 6 December 2005     

The Predictive Power of Survey‐Based Exchange Rate Forecasts: Is there a Role for Dispersion?

Previous research has shown that the consensus of individual exchange rate forecasts performs no better than many commonly used forecasting models in predicting future exchange rates. Studies on equity and bond markets have explored the effects of dispersion in forecasts on the predictive power of forecasts; however, no earlier paper has investigated such effects in the context of the foreign exchange market. This study explores the role of consensus forecast dispersion as a factor leading to bias and anchoring in exchange rate forecasts. Our analysis of five currency pairs reveals that consensus forecasts mostly appear to be unbiased predictors of exchange rates in the long run, but most are unable to pass tests for short‐run unbiasedness. In three of the five currencies examined it appears that forecasters should take greater account of reported forecast dispersion. Copyright © 2015 John Wiley & Sons, Ltd.     

Which strategy for a protein crystallization project?

The three-dimensional, atomic-resolution protein structures produced by X-ray crystallography over the past 50+ years have led to tremendous chemical understanding of fundamental biochemical processes. The pace of discovery in protein crystallography has increased greatly with advances in molecular biology, crystallization techniques, cryocrystallography, area detectors, synchrotrons and computing. While the methods used to produce single, well-ordered crystals have also evolved over the years in response to increased understanding and advancing technology, crystallization strategies continue to be rooted in trial-and-error approaches. This review summarizes the current approaches in protein crystallization and surveys the first results to emerge from the structural genomics efforts.Received 1 July 2003; received after revision 6 August 2003; accepted 22 August 2003     

The structure of human interferon-β: implications for activity

Interferons (IFNs) are potent extracellular protein mediators of host defence and homoeostasis. This article reviews the structure of human IFN-β (HuIFN-β), in particular in relation to its activity. The recently determined crystal structure of HuIFN-β provides a framework for understanding of the mechanism of differentiation of type I IFNs by their common receptor. Insights are generated by comparison with the structures of other type I IFNs and from the interpretation of existing mutagenesis data. The details of the observed carbohydrate structure, together with biochemical data, implicate the glycosylation of HuIFN-β, which is uncommon among type I IFNs, as an important factor in the solubility, stability and, consequently, activity of the protein. Finally, these structural implications are discussed in the context of the clinical use of HuIFN-β. Received 12 June 1998; received after revision 16 July 1998; accepted 16 July 1998     

The landing zone – Ground for model transfer in chemistry

This essay proposes a new notion - the landing zone - in order to identify conceptual features that allow modelers to transfer mathematical tools across disciplinary borders. This discussion refers to the transferable models as ‘templates’. Templates are functions, equations, or computational methods that are capable of being generalized from a particular subject matter. There are formal and conceptual prerequisites for the transfer of a template to a new domain. A landing zone is an ontology that contributes to the satisfaction of these conditions for successful transfer. This paper presents a case study on a model in chemistry - the Quantum Theory of Atoms in Molecules (QTAIM) - that makes use of transferred templates from physics - the virial theorem and the wave function. The landing zone in this case is a new ontological notion, that of the topological atom, which prepares ground for the use of the virial theorem and the wave function in chemistry. The virial theorem requires that there exists in-principle stability to the system that it represents, and the wave function requires transformation in its representation that is justified. The ontology of QTAIM - the landing zone for these templates - grounds the scientific use of these templates in the context of chemistry.     

The life and death of a scientific instrument: The marine chronometer, 1770–1920

Successful prototype marine chronometers, developed by Harrison and others in the eighteenth century, stimulated a sector of the British watchmaking industry to supply Admiralty and commercial demand for this instrument. Chronometers, like other British-made timepieces, were constructed by an elaborate pre-industrial method of production. The instrument's static technology and extreme durability meant replacement demand was minimal, and new demand was low relative to existing stock and the industry's capacity. The First World War created a final surge of demand that left supplies far in excess of peacetime needs; and a new technology—radio transmissions of time signals—offered an alternative method of determining Greenwich time, and thus longitude, at sea.     

The ‘Darwin-Marx correspondence’: a correction and revision

The logical links between the Judaeo-Christian doctrine of creation and the practice of natural philosophy on the one hand, and the rejection of belief in demonic agency on the other, were made explicit in the seventeenth century by, among others, Balthasar Bekker (1634–98), whose ideas I argue to have been not without influence. In section 1, I present the accounts of three historians of the opposition to belief in witchcraft and of the decline of the witch-persecution, Hugh Trevor-Roper, Keith Thomas, and Brian Easlea. In section 2, I maintain that Bekker has been underestimated both by Trevor-Roper and by Easlea. In section 3, I investigate more generally some of the connections between the new natural philosophy and belief in supernatural interventions, cast doubt on the view that rejection of belief in witchcraft and the devil requires rejection of belief in creation, and thus supplement or qualify the accounts of Trevor-Roper, Thomas, and Easlea of why belief in witchcraft faded away.     

Triadin: a multi-protein family for which purpose?

Triadin is a protein first identified as a member of the muscle calcium release complex, involved in calcium release for muscle contraction. However, its precise function in this complex is still undefined. Recently, triadin has been shown to be a multi-protein family, with different distribution of the various splice variants within the sarcoplasmic reticulum, raising the possibility of multiple functions for this family of polypeptides. Such functions may include involvement in excitation-contraction coupling, in triad targeting, in structural function or in muscle differentiation. The putative role(s) of triadin(s) will be discussed here.Received 5 May 2004; received after revision 4 June 2004; accepted 7 June 2004     

γδ T-APCs: a novel tool for immunotherapy?

The series of seminal articles in this book clearly illustrate the multi-functional nature of γδ T cells. Some of the functions correlate with the tissue tropism of distinct γδ T cell subsets whereas others appear to result from oligoclonal selection. Here, we discuss the antigen-presenting cell (APC) function of the major subset of circulating γδ T cells, Vγ9/Vδ2 T cells, present in human blood. During tissue culture, Vγ9/Vδ2 T cells uniformly respond to a class of non-peptide antigens, so-called prenyl pyrophosphates, derived from stressed host cells or from microbes. It is this feature that distinguishes human (and primate) Vγ9/Vδ2 T cells from αβ and γδ T cells of all other species and that forms the basis for detailed studies of human Vγ9/Vδ2 T cells. One of the consequences of Vγ9/Vδ2 T cell activation is the rapid acquisition of APC characteristics (γδ T-APCs) reminiscent of mature dendritic cells (DCs). In the following discussion, we will discriminate between the potential use of γδ T-APCs as a cellular vaccine in immunotherapy and their role in anti-microbial immunity. Exploiting the APC function in γδ T-APCs represents a true novelty in current immunotherapy research and may lead to effective, anti-tumor immunity in cancer patients.     

The peroxisomal protein import machinery – a case report of transient ubiquitination with a new flavor

The peroxisomal protein import machinery displays remarkable properties. Be it its capacity to accept already folded proteins as substrates, its complex architecture or its energetics, almost every aspect of this machinery seems unique. The list of unusual properties is still growing as shown by the recent finding that one of its central components, Pex5p, is transiently monoubiquitinated at a cysteine residue. However, the data gathered in recent years also suggest that the peroxisomal import machinery is not that exclusive and similarities with p97/Cdc48-mediated processes and with multisubunit RING-E3 ligases are starting to emerge. Here, we discuss these data trying to distill the principles by which this complex machinery operates. Received 16 July 2008; received after revision 25 August 2008; accepted 29 August 2008