The use of benzylpenicillinacylase fromEscherichia coli in the resolution of some racemicβ-,γ-,δ- andɛ-amino-acids

Summary The enzymatic hydrolysis of N-phenylacetyl derivatives of racemic amino-acids having the chiral centre removed from the usual -position is examined. The reaction is found to have different degrees of stereoselectivity. In the case of -amino-acids and of -aminovaleric acid, both enantiomers can be obtained in good yields and high optical purity. S-directed stereochemical preference was found for all the substrates examined.     

Rôle of the nucleus in the maintenance of the protein level in the algaAcetabularia mediterranea

Riassunto Sono state studiate le variazioni del rapporto tra l'N proteico e non proteico in segmenti rigeneranti, nucleati ed anucleati, diAcetabul. medit. I risultati ottenuti hanno dimostrato che il predetto rapporto aumenta in entrambi i segmenti il primo giorno dopo l'operazione. Nei giorni seguenti esso diminuisce in entrambi i segmenti, ma più sensibilmente in quelli anucleati, nei quali va al di sotto del valore medio delle alghe normali già dopo il 3°–4° giorno.     

Dopamine-β-hydroxylase,adrenaline, noradrenaline and dopamine in the venous blood of adrenal gland of man: A comparison with levels in the periphery of the circulation

Summary In 10 human subjects plasma dopamine--hydroxylase activity was found in the adrenal vein blood to be as high as in the periphery of the circulation. Adrenaline concentration in the adrenal vein blood was in the mean 170 times, noradrenaline concentration 11 times and dopamine concentration little higher than levels in the periphery.This study was supported by the Deutsche Forschungsgemeinschaft.     

Effect of testosterone and 17-β estradiol on limb regeneration in the newt,Notophthalmus viridescens

Summary Gonadectomy, or injections of testosterone or 17- estradiol, had no apparent effect on the rate of regeneration or histological appearance of limb regenerates in the newt,Notophthalmus viridescens. Neither promotion, nor inhibition of limb regeneration was observed.This work was supported by a grant from the National Research Council of Canada to S.R.S.     

Characterization of 17β-estradiol 3-(β-D-glucopyranoside) and 17-(α-D-glucopyranoside) as the metabolites of 17β-estradiol in the cultured ovaries of the silkworm,Bombyx mori

Summary The structures of the metabolites formed upon incubation of 17-estradiol with the ovaries of silkworm,Bombyx mori, have been determined as 17-estradiol 3-(-D-glucopyranoside) (1) and 17-(-D-glucopyranoside) (2) by spectroscopic means.     

The platypus in Edinburgh: Robert Jameson,Robert Knox and the place of the Ornithorhynchus in nature, 1821–24

The duck-billed platypus, or Ornithorhynchus, was the subject of an intense debate among natural historians in the late eighteenth and early nineteenth centuries. Its paradoxical mixture of mammalian, avian and reptilian characteristics made it something of a taxonomic conundrum. In the early 1820s Robert Jameson (1774–1854), the professor of natural history at the University of Edinburgh and the curator of the University's natural history museum, was able to acquire three valuable specimens of this species. He passed one of these on to the anatomist Robert Knox (1791–1862), who dissected the animal and presented his results in a series of papers to the Wernerian Natural History Society, which later published them in its Memoirs. This paper takes Jameson's platypus as a case study on how natural history specimens were used to create and contest knowledge of the natural world in the early nineteenth century, at a time when interpretations of the relationships between animal taxa were in a state of flux. It shows how Jameson used his possession of this interesting specimen to provide a valuable opportunity for his protégé Knox while also helping to consolidate his own position as a key figure in early nineteenth-century natural history.     

α-Endosulfine, a new entity in the control of insulin secretion

ATP-dependent potassium (K_ATP) channels occupy a key position in the control of insulin release from the pancreatic β cell since they couple cell polarity to metabolism. These channels close when more ATP is produced via glucose metabolism. They are also controlled by sulfonylureas, a class of drugs used in type 2 diabetic patients for triggering insulin secretion from β cells that have lost part of their sensitivity to glucose. We have demonstrated the existence of endogenous counterparts to sulfonylureas which we have called ‘endosulfines.’ In this review, we describe the discovery, isolation, cloning, and biological features of the high-molecular-mass form, α-endosulfine, and discuss its possible role in the physiology of the β cell as well as in pathology. Received 1 February 1999; received after revision 26 March 1999; accepted 26 March 1999     

Good, bad or offal? The evaluation of raw pancreas therapy and the rhetoric of control in the therapeutic trial, 1925

In 1925 a debate erupted in the correspondence columns of the British Medical Journal concerning the effectiveness of eating raw pancreas as a treatment for diabetes. Enthusiasts were predominantly general practitioners (GPs), who claimed success for the therapy on the basis of their clinical impressions. Their detractors were laboratory-oriented 'biochemist-physicians,' who considered that their own experiments demonstrated that raw pancreas therapy was ineffective. The biochemist-physicians consistently dismissed the GPs' observations as inadequately 'controlled'. They did not define the meaning of 'control' in this context, although it clearly did not have the term's present-day meaning of a trial employing an untreated comparison group of patients. Rather, the physician-biochemists' 'properly controlled' experiments involved careful regulation of their patients' diet and other environmental factors, and evaluation of the therapy's success through biochemical, rather than just clinical, criteria. However, my analysis suggests that these factors alone are inadequate to account for the biochemist-physicians' dismissal of the GPs' work as 'uncontrolled'. I suggest that the biochemist-physicians were deliberately exploiting the powerful rhetorical connotations of the term 'control'. Ultimately, they implied that only a trial which they themselves had conducted could be deemed 'adequately controlled'.     

Science in the american south through the eyes of four natural historians, 1750–1850

A national scientific community developed in the United States following the American Revolution. The independent scientific societies, journals and other institutions that formed the basis of this community were, however, centred in the North. An analysis of the work of four leading natural historians of the Southern tidewater (two from before the Revolution and two from after it) suggests that their region participated in this development by shifting scientific ties and allegiances from Europe to the North rather than by creating national or regional scientific institutions.     

Localisation of acetylcholinesterase in rat myotubes in the presence of β-endorphin and β-endorphin-(1-27)

Summary In rat embryo skeletal myotubes, acetylcholinesterase is present, as multiple forms, and can be detected in deposits at the cell surface. Myotubes cultured in the presence of -endorphin, exhibit an increased predominance of the globular (precursor) forms of the enzyme, which are largely restricted to intracellular sites associated with nuclei. In the presence of -endorphin-(1-27), the relative proportions of the different forms of acetylcholinesterase is similar to that seen in the controls, but the enzyme is intracellular and has a characteristic focal localisation in the myotube.     

Does the ectodermal proctodaeum participate in the development of the pronephric duct in urodele amphibia?

Zusammenfassung Vom ektodermalen Proctodaeum wächst ein kleiner Divertikel dem Vornierengang entgegen und vereinigt sich mit dessen kaudalem Ende. Einen weiteren Anteil hat das Proctodaeum an der Bildung des Vornierenganges nicht. Zugleich mit dem Proctodaeum invaginiert Material für den Mesonephros, das sich in Zellgruppen entlang dem hinteren Ende des Vornierenganges lagert.     

26-Hydroxy-β-ecdysone,a metabolite of β-ecdysone in the blowfly,Calliphora erythrocephala

Summary 26-Hydroxy--ecdysone has been identified as a metabolite of the moulting hormone, -ecdysone inCalliphora erythrocephala.     

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.     

'Through thousands of errors we reach the truth' - but how? On the epistemic roles of error in scientific practice

This essay is concerned with the epistemic roles of error in scientific practice. Usually, error is regarded as something negative, as an impediment or obstacle for the advancement of science. However, we also frequently say that we are learning from error. This common expression suggests that the role of error is not - at least not always - negative but that errors can make a fruitful contribution to the scientific enterprise. My paper explores the latter possibility. Can errors play an epistemically productive role in scientific research? The paper begins with a review of several twentieth-century approaches to error and the various agendas behind them. It is shown that only very few scholars have considered whether errors can be productive. The main part of the paper examines a concrete debate in early nineteenth-century on this material, the article offers some terminological clarifications of the common notion 'learning from error'. The conclusion argues that error can indeed play epistemically productive roles in scientific practice.