Cyclisation of α-benzylhomophthalic acids

Résumé Les cyclisations des acides -benzylhomophthaliques ont produit un keto-acide à 7 termes, un indenoisocoumarin ou un mélange des deux.     

Electrochemical behaviour ofβ-carotene with strong acids

Zusammenfassung Die Einwirkung von starken Säuren auf-Carotin in geeigneten Lösungsmitteln führte zur Bildung von blauen Farbstoffen. Bei Anwendung von mono- und polybasischen Säuren wanderten diese neuen Stoffe meistens kathodisch, wenn die Säurekonzentration schwach war. Manchmal, vor allem bei stärkerer Konzentration oder nach längerem Stehen der Lösungen, wanderten sie anodisch.     

Hydrolysis of N-phenylacetyl-α-methyl-α-amino acids by benzylpenicillinacylase

Summary Enzymatic hydrolysis of several racemic N-phenylacetyl--methyl--amino acids containing an additinal aliphatic, aromatic or polar substitutent on the chiral carbon atom, has been studied by using benzylpenicillincylase fromEscherichia coli A.T.C.C. 9637. Both the rate of hydrolysis and the stereoselectivity were found to be considerably lower than in the case of natural -amino acids. Steric and electronic factors in the side chains influencing the stereoselectivity are discussed.     

Dissociation constants of water-insoluble carboxylic acids by13C-NMR. pK as of mesobiliverdin-XIIIα and mesobilirubin-XIIIα

High-field¹³C-NMR of¹³C-enriched compounds in dilute aqueousd ₆-Me₂SO solutions provides a simple, accurate method for measuring pK _as of sparingly soluble carboxylic acids. Using this method, we found the pK _as of mesobilirubin-XIII to be 4.2 and 4.9, much lower values than reported recently for bilirubin, and of mesobiliverdin-XIII to be 3.9 and 5.3.     

A group of fatty acids with ‘tetramethylene interruption’ in the double bond system

Zusammenfassung In Blättern und Nüssen vonGinkgo biloba wurde eine Gruppe ungesättigter Fettsäuren gefunden, die in ihrer Struktur von der üblichen Anordnung der Doppelbindungen in Fettsäuren abweichen. Jede der ungewöhnlichen Säuren hat die «isolierte» Doppelbindung in ⁵-Position, was auf eine neuartige Biosynthese dieser Dien-, Trien- und Tetraensäuren hinweist.

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This work has been supported by a research grant from the National Institutes of Health (USPHS AM-05165) and by the Hormel Foundation.     

The application of Hudson's lactone rule toγ- andδ-hydroxyamino acids and the question of the configuration ofδ-hydroxy-l-lysine from collagen

Zusammenfassung Die Anwendung von Hudsons Lakton-Regel auf eine Reihe von Laktonen von- und-Oxyaminosäuren bestätigte die unabhängig auf chemischem Wege bewiesenen Konfigurationen an den- und-Kohlenstoffatomen. Im Falle des erstmalig dargestellten Laktons des,-Dibenzoyl--hydroxy-d-lysins führte die Anwendung der Regel zurerythro-Struktur XV, und folglich für natürliches-Oxylysin aus Collagen zur Formel XIa, deren Beweis auf chemischem Wege noch aussteht.     

Is there any quantitative relationship between the synthesis and the breakdown of nucleic acids in living cells?

Zusammenfassung Es wurde untersucht, ob die Biosynthese der Nukleinsäuren in wachsenden Systemen mit dem Abbau von ursprünglich vorhandenen Nukleinsäuren derselben Art gekoppelt ist. Die Versuche wurden mit Bakterien (E. coli) und mit Rattenleber gemacht. Die in der Zelle vorhandenen Nukleinsäuren waren mit P³² markiert, und es wurde der Verlust an Radioaktivität in jeder der beiden Nukleinsäuretypen im Laufe des Wachstums gemessen. Die Resultate wiesen darauf hin, dass das Auftreten von neuen Nukleinsäuremolekeln in der lebenden Zelle ohne den begleitenden Abbau der alten Molekeln stattfinden kann.

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Supported in part by the Scientific Research Fund of the Ministry of Education given to the Synthetic Research Group on Nucleic Acids. The warm encouragement given to this work by Prof.J. Kamahora of this Institute is heartily acknowledged. We are further indebted to Dr.T. Miura, Department of Radiology, University of Osaka Medical School, for his help in this work.     

Physiological importance of ω-3/ω-6 polyunsaturated fatty acids in man. An overview of still unresolved and controversial questions

Summary The essentiality of (-6) and (-3) fatty acids in mammals is well known. Nevertheless, some important points remain unclear concerning their implication in physiology. After a short discussion about the definition of essential fatty acids deficiency, this brief overview deals with some of these points, pointing out some of the unresolved questions. Different subjects are approached concerning the (-6) and (-3) fatty acids metabolism: desaturases, eicosanoids, production, as well as some of their metabolic effects on cell membranes, intestinal function, glucose and lipid metabolism, haemorheology.     

Observations on the nucleic acids during the development of the lethal hybridTriton palmatus ♀ ×Salamandra atra ♂

Zusammenfassung Der Gehalt an Ribonukleinsäure und Desoxyribonukleinsäure der normalen Tritoneier (T.palmatus) und der letalen Bastardeier (T.palmatus ×S.atra ) wurde im Morula-, Blastula- und Gastrulastadium mikrophotometriert. Bei normalen Eiern wurde keine wesentliche Änderung des Ribonukleinsäuregehaltes festgestellt. Hingegen nahm die Konzentration der Desoxyribonukleinsäure von der späten Morula bis zur mittleren Blastula deutlich zu und zeigte dann bis zum Gastrulastadium nur geringe Zunahme.Während der Furchung ist der Nukleinsäurengehalt der Bastardeier normal. Die mittlere Blastula (kritische Phase: etwa 24 h bei 18°C) ist aber gegenüber den Kontrollkeimen bedeutend ärmer an beiden Nukleinsäuren. Eine leichte Zunahme der Desoxyribonukleinsäure vor der kritischen Phase, ohne jedoch die Konzentration eines normalen Eies zu erreichen, wurde beobachtet. Die entwicklungsphysiologische Deutung der vorliegenden Befunde wird diskutiert.

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This work was supported by a grant from the Karl-Hescheler-Stiftung.     

Free intracellular and protein bound amino acids in tissues as affected by a mixedβ-adrenergic agonist

The administration of metaproterenol induced an increase in gastrocnemius muscle weight without change in body growth rate or tissue protein concentrations, while epididymal fat was reduced. This effect was accompanied by an enhancement in the levels of intracellular amino acids in muscle. By contrast, liver amino acids were unaffected by treatment with the mixed -adrenergic agonist.     

Activation ofα-carbons of amides

Summary The reactions of Vilsmeir complexes of amides/imides with electrophiles afford the corresponding -substituted products in good yield.     

Influence of the structure of theN-terminal extremity ofα-MSH on the melanophore stimulating activity of this hormone

Zusammenfassung Drei strukturelle Analoge des-MSH wurden synthetisiert und auf ihre Melanophoren-stimulierende Wirksamkeit untersucht. Für das Auftreten einer ausgeprägten biologischen Aktivität scheint die Anwesenheit einerN-Acetyl-Gruppe an dem Aminoende der Peptidkette wichtiger zu sein als das Vorhandensein der zwei ersten amino-endständigen Aminosäurereste der-MSH-Kette.     

Lagrange’s theory of analytical functions and his ideal of purity of method

We reconstruct essential features of Lagrange’s theory of analytical functions by exhibiting its structure and basic assumptions, as well as its main shortcomings. We explain Lagrange’s notions of function and algebraic quantity, and we concentrate on power-series expansions, on the algorithm for derivative functions, and the remainder theorem—especially on the role this theorem has in solving geometric and mechanical problems. We thus aim to provide a better understanding of Enlightenment mathematics and to show that the foundations of mathematics did not, for Lagrange, concern the solidity of its ultimate bases, but rather purity of method—the generality and internal organization of the discipline.     

Characterization of the role of metallothionein-3 in an animal model of Alzheimer’s disease

Among the dementias, Alzheimer’s disease (AD) is the most commonly diagnosed, but there are still no effective drugs available for its treatment. It has been suggested that metallothionein-3 (MT-3) could be somehow involved in the etiology of AD, and in fact very promising results have been found in in vitro studies, but the role of MT-3 in vivo needs further analysis. In this study, we analyzed the role of MT-3 in a mouse model of AD, Tg2576 mice, which overexpress human Amyloid Precursor Protein (hAPP) with the Swedish mutation. MT-3 deficiency partially rescued the APP-induced mortality of females, and mildly affected APP-induced changes in behavior assessed in the hole-board and plus-maze tests in a gender-dependent manner. Amyloid plaque burden and/or hAPP expression were decreased in the cortex and hippocampus of MT-3-deficient females. Interestingly, exogenously administered Zn₇MT-3 increased soluble Aβ40 and Aβ42 and amyloid plaques and gliosis, particularly in the cortex, and changed several behavioral traits (increased deambulation and exploration and decreased anxiety). These results highlight that the control of the endogenous production and/or action of MT-3 could represent a powerful therapeutic target in AD.     

Luteolytic potency of 16-phenoxy-derivatives of prostaglandin F2α

Summary The binding of 16-phenoxy derivatives of prostaglandin (PG) F₂ to rat luteal membranes, and also their abortifacient potency in pregnant rats, have been studied. Competitive binding studies with various PG-analogues were performed in ovaries of juvenile rats pretreated with PMSG and HCG, and in parallel studies the abortifacient potency of these substances was tested, in pregnant rats. It was observed that this class of derivatives bound to the PGF₂ receptor as well as, or even better than the parent compound PGF₂. Modifications in the carboxyl group at C-1 yielded derivatives with a higher affinity for the receptor, in decreasing order of effectiveness as follows:-COOR>COOH>OH. The data obtained from the binding studies also compared well with data on the abortifacient potency in pregnant rats. It is concluded that the addition of a phenoxy group to either the lower or upper side chain of PGF₂ may augment the binding to the receptor as well as the biological responses induced by the post receptor effect.     

‘Binding’ of glycine andγ-aminobutyric acid to synaptosomal fractions of 6 regions of the feline brain; effects of strychnine

Summary GABA (6×10^–6 M) binding to synaptosome-enriched fractions of cat CNS exhibited a clear rostro-caudal gradient, whereas glycine (6×10^–6 M) binding was greatest to particles of cerebellar cortex, and this was followed by medulla caudate nucleus cerebral cortex pons > corona radiata. Strychnine-SO₄ (10^–3 or 10^–4 M) inhibited the binding of GABA and glycine in all brain regions studied; at 10^–5 M this drug inhibited the binding of both GABA and glycine only to particles of the cerebral cortex.This study was supported by Centro Nacional Ramón y Cajal and Fundación Juan March. P. M. was a summer student from Eastern Nazarene College, Wollaston, Mass., USA.     

Distribution of tightened end fragments of globular proteins statistically matches that of topohydrophobic positions: towards an efficient punctuation of protein folding?

Using a set of 372 proteins representative of a variety of 56 distinct globular folds, a statistical correlation was observed between two recently revealed features of protein structures: tightened end fragments or 'closed loops', i. e. sequence fragments that are able in three-dimensional (3D) space to nearly close their ends (a current parameter of polymer physics), and 'topohydrophobic positions', i. e. positions always occupied in 3D space by strong hydrophobic amino acids for all members of a fold family. Indeed, in sequence space, the distribution of preferred lengths for tightened end fragments and that for topohydrophobic separation match. In addition to this statistically significant similarity, the extremities of these 'closed loops' may be preferentially occupied by topohydrophobic positions, as observed on a random sample of various folds. This observation may be of special interest for sequence comparison of distantly related proteins. It is also important for the ab initio prediction of protein folds, considering the remarkable topological properties of topohydrophobic positions and their paramount importance within folding nuclei. Consequently, topohydrophobic positions locking the 'closed loops' belong to the deep cores of protein domains and might have a key role in the folding process. Received 1 February 2001; accepted 7 February 2001     

‘Binding’ of glutamate and aspartate to synaptosomal fractions of six regions of the feline brain

The order of potency of binding of both glutamate and aspartate to synaptosomal fractions of brain regions was: cerebellar cortex caudate nucleus cerebral cortex > medulla pons > corona radiata. Glutamate was bound to a greater extent than aspartate to particles of all regions studied, except for cerebral cortex.     

Determination of diel periodicity of sex pheromone release in three species of Lepidoptera by ‘closed-loop-stripping’

Summary By means of closed-loop-stripping and subsequent GC analyses the diel periodicity of release of (Z)-11-hexadecenyl acetate, (E)-8-dodecenyl acetate, and (Z)-9-tetradecenyl acetate, the main constituents of the respective sex pheromone blends ofMamestra brassicae, Cryptophlebia leucotreta andSpodoptera sunia females, was determined.Pheromones, 64. For the 63rd contribution we have taken from: Szöcs, G., Toth, M., Bestmann, H. J., Vostrowsky, O., Heath, R. R., and Tumlinson, J. H., Z. Naturforsch.42c (1987) 165; Pheromones, 62: Bestmann et al.¹³.