Nicotianamine,the ‘normalizing factor’ for the auxotroph tomato mutantChloronerva; a representative of a new class of plant effectors

Summary The article surveys our knowledge of the normalizing factor, gained from its discovery a quarter of a century ago up to the present time, under the following headings: Discovery; Physiological properties; Isolation and characterization; Structure determination (Identity of the normalizing factor with nicotianamine); Chemical properties; Analysis; Synthesis; Occurrence and physiological role; Related compounds; Prospects.     

Observations on the neuropathology of ‘reeler’, a neurological mutation in mice

Zusammenfassung Eine genetisch bedingte Bewegungsstörung in der Hausmaus «reeler» wurde untersucht. Der Erbgang der «reeler»-Mutation ist einfach rezessiv. In homozygotem Zustand führt das Gen zu Gleichgewichtsstörungen und leichtem Zittern.Das Studium der Morphologie des Gehirns der «reeler»-Mäuse ergab, dass die Cytoarchitektonik des Kleinhirns in dieser Mutante verändert und teilweise zerstört ist.

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Supported by Grant No. B-1716 from USPHS National Institute of Neurological Diseases and Blindness.     

Spectrin and calpain: a ‘target’ and a ‘sniper’ in the pathology of neuronal cells

It is well documented that activation of calpain, a calcium-sensitive cysteine protease, marks the pathology of naturally and experimentally occuring neurodegenerative conditions. Calpain-mediated proteolysis of major membrane-skeletal protein, αII-spectrin, results in the appearance of two unique and highly stable breakdown products, which is an early event in neural cell pathology. This review focuses on spectrin degradation by calpain within neurons induced by diverse conditions, emphasizing a current picture of multi-pattern neuronal death and a recent success in the development of spectrin-based biomarkers. The issue is presented in the context of the major structural and functional properties of the two proteins.Received 7 March 2005; received after revision 22 April 2005; accepted 13 May 2005     

Morphological and histochemical demonstration of a glycocalyx on the cell surface ofChattonella antiqua,a ‘naked flagellate’

Summary Electron microscopy demonstrated the presence of glycocalyx on the cell surface ofChattonella antiqua, which was previously believed to be naked. Histochemical analysis of this structure indicates that the glycocalyx consists of at least two different types of acidic complex carbohydrates, sulfated and nonsulfated, together with a neural carbohydrate-protein complex with 1,2-glycol groups and -D-mannosyl and -D-glucosyl residues.     

‘The happy thought of a single man’: On the legendary beginnings of a style of reasoning

In this paper I direct attention to one feature of Hacking’s recent work on styles of reasoning and argue that this feature is of far greater philosophical significance than Hacking’s limited discussion of this suggests. The feature in question is his use of ‘legendary beginnings’ in setting out a given style, viz. the method of introducing a style of reasoning by recounting a popular and quasi-mythical narrative that ties the crystallisation of that style to a particular person in a particular place and at a particular time. Whilst Hacking both deploys and discusses this method, his comments suggest that this is primarily a stylistic device employed for reasons of expedience. In contrast, it is argued here that recounting the legendary origins of a style of reasoning affords a distinctive way of vindicating that style, a vindication from within the style itself.     

‘The accomplishment of many years’: Three notes towards a history of the sand-glass

The first note examines current assumptions about the medieval origins of the sand-glass and underlines the defective nature of our knowledge. The second note suggests a possible etymology for an unusual fifteenth-century English term for the instrument. The third note assembles such evidence as can be found on the price of sand-glasses and the structure of the trade that produced them.     

A fungus pigment of novel type,and the nature of fungus ‘lignin’

Zusammenfassung In den Früchten des höheren PilzesPolyporus hispidus bildet sichin situ ein ligninähnlicher Stoff durch Oxidation-Polymerisation von Phenolen des Phenylpropantyps, hauptsächlich Hispidin (I), dessen Struktur als Enollacton der 3,4-Dihydroxycinnamoylacetessigsäure erkannt wurde.     

Duncan F. Gregory,William Walton and the development of British algebra: ‘algebraical geometry’, ‘geometrical algebra’, abstraction

This paper provides a detailed account of the period of the complex history of British algebra and geometry between the publication of George Peacock's Treatise on Algebra in 1830 and William Rowan Hamilton's paper on quaternions of 1843. During these years, Duncan Farquharson Gregory and William Walton published several contributions on ‘algebraical geometry’ and ‘geometrical algebra’ in the Cambridge Mathematical Journal. These contributions enabled them not only to generalize Peacock's symbolical algebra on the basis of geometrical considerations, but also to initiate the attempts to question the status of Euclidean space as the arbiter of valid geometrical interpretations. At the same time, Gregory and Walton were bound by the limits of symbolical algebra that they themselves made explicit; their work was not and could not be the ‘abstract algebra’ and ‘abstract geometry’ of figures such as Hamilton and Cayley. The central argument of the paper is that an understanding of the contributions to ‘algebraical geometry’ and ‘geometrical algebra’ of the second generation of ‘scientific’ symbolical algebraists is essential for a satisfactory explanation of the radical transition from symbolical to abstract algebra that took place in British mathematics in the 1830s–1840s.     

The folding process of hen lysozyme: a perspective from the ‘new view’

How a conformationally disordered polypeptide chain rapidly and efficiently achieves its well-defined native structure is still a major question in modern structural biology. Although much progress has been made towards rationalizing the principles of protein structure and dynamics, the mechanism of the folding process and the determinants of the final fold are not yet known in any detail. One protein for which folding has been studied in great detail by a combination of diverse techniques is hen lysozyme. In this article we review the present state of our knowledge of the folding process of this enzyme and focus in particular on recent experiments to probe some of its specific features. These results are then discussed in the context of the ‘new view’ of protein folding based on energy surfaces and land scapes. It is shown that a schematic energy surface for lysozyme folding, which is broadly consistent with our experimental data, begins to provide a unified model for protein folding through which experimental and theoretical ideas can be brought together.     

What's nu? A re-examination of Maxwell's ‘ratio-of-units’ argument,from the mechanical theory of the electromagnetic field to ‘On the elementary relations between electrical measurements’

This re-examination of the earliest version of Maxwell's most important argument for the electromagnetic theory of light—the equality between the speed of wave propagation in the electromagnetic ether and the ratio of electrostatic to electromagnetic measures of electrical quantity—establishes unforeseen connections between Maxwell's theoretical electrical metrology and his mechanical theory of the electromagnetic field. Electrical metrology was not neutral with respect to field-theoretic versus action-at-a-distance conceptions of electro-magnetic interaction. Mutual accommodation between these conceptions was reached by Maxwell on the British Association for the Advancement of Science (BAAS) Committee on Electrical Standards by exploiting the measurement of the medium parameters—electric inductive capacity and magnetic permeability—on an arbitrary scale. While he always worked within this constraint in developing the ‘ratio-of-units’ argument mathematically, I maintain that Maxwell came to conceive of the ratio ‘as a velocity’ by treating the medium parameters as physical quantities that could be measured absolutely, which was only possible via the correspondences between electrical and mechanical quantities established in the mechanical theory. I thereby correct two closely-related misconceptions of the ratio-of-units argument—the counterintuitive but widespread notion that the ratio is naturally a speed, and the supposition that Maxwell either inferred or proved this from its dimensional formula.     

Reflecting ‘Popular Culture’: The Introduction,Diffusion, and Construction of the Reflecting Telescope in the Netherlands

The eighteenth century was an era in which science came to play a major role in the cultural ideal of the city elite. The phenomenon of the ‘gentleman-scientist’ arose: a layman without a scientific education who for a variety of often socially desirable reasons devoted himself to scientific endeavours. Scientific instruments were the tools for this interest. This article describes the introduction, diffusion, and construction in the Netherlands of one of the most prominent eighteenth-century instruments: the reflecting telescope. The reception of this instrument casts new light on the usually almost invisible network of gentleman-scientists and instrument-makers in this region. The specific economic and political factors of the Netherlands led to a totally different development of this instrument compared with the ‘motherland’ England. Whereas in Great Britain the reflecting telescope was a great success well into the nineteenth century, in the Netherlands it became a symbol of technical inability and stagnation.     

The ‘Spitzenkörper’, centre of the reducing power in the growing hyphal apices of two septomycetous fungi

Summary Redox dyes, such as methylene blue and neutral red, are stably reduced to their leucobase in the Spritzenkörper of the growing hyphal tips ofNeurospora crassa andMonilia fructigena.We acknowledge the support of the Fonds National Suisse de la Recherche Scientifique and thank both Mrs Ton-That for her electron micrograph and Miss E. Herz for her technical help.     

The Hybrid Expert in the ‘Bergstaat’: Anton von Ruprecht as a Professor of Chemistry and Mining and as a Mining Official, 1779–1814

Summary

In the course of the 18th century a new type of scientifically educated functional elites developed, who were trained to administer mines. The educational project that led to the formation of a corps of mining engineers was part of a programme of administrative and economic reforms that led to a new configuration of bonds between state, economy and science. At the same time the status of this new group of experts was predicated substantially by the new emerging corpora of the scientific, technological and cameralist knowledge of the period between 1760 and 1800. The aim of this paper is to discuss this group using the example of a leading expert in the context of the mining and metallurgy of this period. Anton von Ruprecht (1748–1814) was strongly grounded in the social and epistemic context of the Habsburg mining bureaucracy, which employed his scientific and technical savoir faire to serve their mercantile goals in several areas of mining expertise.     

Into the ‘regions of physical and metaphysical chaos’: Maxwell’s scientific metaphysics and natural philosophy of action (agency,determinacy and necessity from theology,moral philosophy and history to mathematics,theory and experiment)

Maxwell’s writings exhibit an enduring preoccupation with the role of metaphysics in the advancement of science, especially the progress of physics. I examine the question of the distinction and the proper relation between physics and metaphysics and the way in which the question relies on key notions that bring together much of Maxwell’s natural philosophy, theoretical and experimental. Previous discussions of his attention to metaphysics have been confined to specific issues and polemics such as conceptions of matter and the problem of free will. I suggest a unifying pattern based on a generalized philosophical perspective and varying expressions, although never a systematic or articulated philosophical doctrine, but at least a theme of action and active powers, natural and human, intellectual and material, with sources and grounds in theology, moral philosophy and historical argument. While science was developing in the direction of professional specialization and alongside the rise of materialism, Maxwell held on to conservative intellectual outlook, but one that included a rich scientific life and held science as part of a rich intellectual, cultural and material life. His philosophical outlook integrated his science with and captured the new Victorian culture of construction and work, political, economic, artistic and engineering.