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.     

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     

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.     

‘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.     

Variability of β-amylase isoenzymes within a collection of inbred lines of rye (Secale cereale L.)

Summary Within one collection of 18 inbred rye lines, seven distinct isoenzymatic patterns of -amylase were found, and five of them formed a group of similar patterns shifting to distinct positions in the gel. It was proved that the shift of the pattern was due to genetic factors. In crossed immunoelectrophoresis, drastic differences were shown in the quantity of the different -amylase constituents. No antigenic differences could be demonstrated between the analyzed isoenzymes.     

Variation of glutamate decarboxylase activity andγ-amino butyric acid content of wheat embryos during ripening of seeds

Summary GAD activity and -ABA content of wheat embryos at 7 ripening stages were verified with the aim of studying the metabolic activity of embryo during dehydration and quiescence of caryopsis. Data showed that in the early stage of ripening GAD activity is very low, increases rapidly at dough-stage, remaining constant up to waxystage, and decreases in the last fully-ripe embryos. -ABA content appears to be roughly parallel to the variations of GAD activity.This work was supported by a grant from the Consiglio Nazionale delle Ricerche.     

Temperature-induced reversal of dominance of variegation in ‘Ornamental kale’

Résumé La transmission de l'albinisme panaché deBrassica oleracea L. ne dépend que d'un seul facteur. Chez les hétérozygotes ce caractère apparaît à basse température (7°C), mais pas à haute température (21°C). Chez les homozygotes le caractère se manifeste probablement toujours, tout en restant peu prononcé à des températures plus élevées. Ainsi il y a une inversion du caractère dominant avec changement de température.     

The rate of cleavage ofβ-mercaptopyruvate by rapidly dividing cells

Zusammenfassung Quantitative Analysen des-mercaptobrenztraubensäure-spaltenden Enzyms zeigen, dass Zellen, die sich in aktivem mitotischem Prozess befinden (bzw. Krebszellen und Gewebekulturen), dieses Enzym in viel geringerem Masse enthalten als « normale » Zellen. Da dieses Enzym in dem anaeroben Stoffwechsel von Zystein eine wichtige Rolle spielt, lässt sich vermuten, dass sich der Zysteinstoffwechsel der Tumorzelle quantitativ von dem der Normalzelle unterscheidet.

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Supported by U.S. Public Health Grants H-2897, C-3211 and by a grant of the American Cancer Society (70-4612-24).     

Completion of the natural groups of ergot alkaloids: Syntheses and pharmacological profiles ofβ-ergosine andβ-ergoptine

Summary The syntheses and pharmacological potencies of -ergosine and -ergoptine, the missing links in the natural groups of ergot peptide alkaloids are described.86th communication on ergot alkaloids.     

The “day of Brahman” in the work of Āryabhata

Summary In the astronomical treatise ryabhatya of ryabhata several verses are interpolated, namely all those verses in which either Brahman was mentioned or extremely large periods were introduced. The interpolator was known to AlBrn as ryabhata of Kusumapura, who belongs to the school of the elder ryabhata. The aim of the interpolator was to bring the teaching of the elder ryabhata into accordance with the revelation of Svayambh. Svayambh is another name for Brahm.     

The oxidative metabolism ofα-chlorohydrin and the chemical induction of spermatocoeles

Summary -Chlorohydrin (I) is oxidatively metabolized to -chlorolactic acid (III) and oxalic acid (IV). Deposition of calcium oxalate within the renal tubules is responsible for the toxic effects of-chlorohydrin and a similar action on the epididymis or epididymal blood vessels could initiate the formation of spermatocoeles from this and other male antifertility agents.     

The steric course of hydrogenation of Δ4 and Δ5 steroids

Zusammenfassung Bei der katalytischen Hydrierung von Steroiden mit Doppelbindung in 4-Stellung entstehen überwiegend A/B-cis-Verbindungen, während Doppelbindung in 5 vor allem A/B-trans liefert. Dieser Unterschied wird mit Hilfe der Konstellationsanalyse erklärt: die als Zwischenformen angenommenen Komplexe aus Substrat, Wasserstoff und Katalysator weisen unterschiedliche sterische Hinderung auf.

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Based in part on a portion of the Ph. D. Thesis of the author, University of Wisconsin, 1951.     

Identification of ϱ-antigenic determinants on the surface,of mouse T-lymphocytes

Summary A monospecific antiserum has been prepared in rabbits against purified -antigen, a 100,000 mol.wt glycoprotein found on the surface of mouse L-cells. This antiserum has been employed to demonstrate the presence of -antigenic determinants selectively on the surface of mouse T-, but not B-lymphocytes.We thank Drs A. Christopher and R. Hunt for advice during the course of these studies. This work was supported by grants from the U.S. Public Health Service and the American Cancer Society.     

The opposed influences ofβ-adrenergic stimulation and adenosine on the frequency-force relationship of isolated left atria of guinea-pigs

Summary The normal frequency-force relationship of left guinea-pig atria can be largely suspended when strong -adrenergic stimulation by orciprenaline is antagonized by the negative inotropic effect of adenosine, so that contraction amplitude is nearly equal at an intermediate level over a wide range of stimulation rates. Curves obtained with a new method for recording continuous frequency-force loops are presented.     

Occurrence of β-chitin in the cuticle of a Pentastomid Raillietiella gowrii

Summary The purified chitin from the cuticle of a pentastomid was examined by X-ray method. The X-ray photograph discloses that the chitin in question is of -type. Since the arthropod cuticle contains -chitin, it is suggested that Pentastomida may be considered an independent phylum.Thanks are due to Prof. Dr. G. Sundara Rajulu for guidance and encouragement.     

The effect of chronic marginal vitamin C deficiency on the α-tocopherol content of the organs and plasma of guinea-pigs

Summary Chronic marginal vitamin C deficiency lasting 270 days induced hypertriglyceridaemia, an abrupt fall of ascorbic acid in all organs and a significant decrease of -tocopherol in the liver and the lungs in guinea-pigs.     

Is attenuation of tRNA charging responsible for the inhibition of protein labelling accompanying depolarisation of the cerebral cortical cells?

Summary Topical application of concentrated solutions of KCl resulted in reduction of charging of tRNA 7 min after s.c. injection of L-(U-¹⁴C) leucine. Neither radioactivity nor pool size of the total amino acids changed during this period.