G-protein signaling: back to the future

Heterotrimeric G-proteins are intracellular partners of G-protein-coupled receptors (GPCRs). GPCRs act on inactive G·GDP/G heterotrimers to promote GDP release and GTP binding, resulting in liberation of G from G. G·GTP and G target effectors including adenylyl cyclases, phospholipases and ion channels. Signaling is terminated by intrinsic GTPase activity of G and heterotrimer reformation – a cycle accelerated by regulators of G-protein signaling (RGS proteins). Recent studies have identified several unconventional G-protein signaling pathways that diverge from this standard model. Whereas phospholipase C (PLC) is activated by G_q and G, novel PLC isoforms are regulated by both heterotrimeric and Ras-superfamily G-proteins. An Arabidopsis protein has been discovered containing both GPCR and RGS domains within the same protein. Most surprisingly, a receptor-independent G nucleotide cycle that regulates cell division has been delineated in both Caenorhabditis elegans and Drosophila melanogaster. Here, we revisit classical heterotrimeric G-protein signaling and explore these new, non-canonical G-protein signaling pathways.Received 21 October 2004; received after revision 20 November 2004; accepted 30 November 2004     

1,2-Methylen-19-nor-17α-acetoxy-progesteron

Summary The syntheses and structure-determinations of 1, 22- and 1, 2-methylene-19-nor-17-acetoxy-progesterones described prove that there is no influence of the angular C₁₀-methylgroup on the steric course of theCourey-methylenations of ¹-3-keto-steroids.     

Flavonoids of Gnaphalieae:Leontopodium alpinum cass

Riassunto Dalla Stella alpina (Leontopodium alpinum Cass, Gnaphalieae-Asteraceae) vengono isolati la luteolina (3, 4, 5, 7 tetraidrossiflavone) ed i suoi 4-e 7-O--d glucosidi.     

7α-hydroxylation of dehydroepiandrosterone in human testis and epididymis in vitro

Zusammenfassung Zerhackte menschliche Hoden und Epididymis wurden mit Dehydroepiandrosteron ohne Kofaktoren bebrütet und es wurden unter anderem 7-und 7-Hydroxydehydroepiandrosteron und 5-Androsten-3, 7, 17-triol charakterisiert. Die Ausbeute an 7-hydroxylierten Metaboliten war fast gleich in Hoden und Epididymis.

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The authors wish to thank Mr.J. Novák for his excellent technical assistance. We are indebted to Dr.J. E. Jirásek for generous performance of histological control of tissue and to Dr.S. Röhling for his kind pernission of radioactivity measurements.     

The mechanism of blood vessel permeability derangement under the influence of histamine,serotonin and bradykinin

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Deamination by ‘Transformed’ mitochondrial amine oxidase of the ε-amino group of lysine and selective inhibition of this reaction by β-aminopropionitrile

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Neue Gesichtspunkte zum 5. Buch Euklids

Summary The author's purpose is to read the main work of Euclid with modern eyes and to find out what knowledge a mathematician of today, familiar with the works of V. D. Waerden and Bourbaki, can gain by studying Euclid's theory of magnitudes, and what new insight into Greek mathematics occupation with this subject can provide.The task is to analyse and to axiomatize by modern means (i) in a narrower sense Book V. of the Elements, i.e. the theory of proportion of Eudoxus, (ii) in a wider sense the whole sphere of magnitudes which Euclid applies in his Elements. This procedure furnishes a clear picture of the inherent structure of his work, thereby making visible specific characteristics of Greek mathematics.After a clarification of the preconditions and a short survey of the historical development of the theory of proportions (Part I of this work), an exact analysis of the definitions and propositions of Book V. of the Elements is carried out in Part II. This is done word by word. The author applies his own system of axioms, set up in close accordance with Euclid, which permits one to deduce all definitions and propositions of Euclid's theory of magnitudes (especially those of Books V. and VI.).In this way gaps and tacit assumptions in the work become clearly visible; above all, the logical structure of the system of magnitudes given by Euclid becomes evident: not ratio — like something sui generis — is the governing concept of Book V., but magnitudes and their relation of having a ratio form the base of the theory of proportions. These magnitudes represent a well defined structure, a so-called Eudoxic Semigroup with the numbers as operators; it can easily be imbedded in a general theory of magnitudes equally applicable to geometry and physics.The transition to ratios — a step not executed by Euclid — is examined in Part III; it turns out to be particularly unwieldy. An elegant way opens up by interpreting proportion as a mapping of totally ordered semigroups. When closely examined, this mapping proves to be an isomorphism, thus suggesting the application of the modern theory of homomorphism. This theory permits a treatment of the theory of proportions as developed by Eudoxus and Euclid which is hardly surpassable in brevity and elegance in spite of its close affinity to Euclid. The generalization to a classically founded theory of magnitudes is now self-evident.

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Vorgelegt von J. E. Hofmann     

Cyclic AMP and cyclic GMP in rats paw edema by prostaglandins

Summary Experimental results indicate that rat's paw oedema development by PGs is inhibited by 35 AMP and increased by 35 GMP. This research confirms the opposite effect to that of cyclic nucleotides. The respective behaviour of 35 AMP and 35GMP in their primary oedema-induced activity is discussed.We gratefully acknowledge the technical assistence of Mr.Sauro Pellegrini.     

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.     

Mass spectrometric determination of the amino acid sequence in cystine- and cysteine-containing peptides

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Synthese von 22,26-Imino-cholestan-Derivaten

Summary 3, 16-diacetoxy-5-pregnane-20-one and the analogue pregn-5-ene derivative have been converted into (22R, 25R)-22, 26-imino-5-cholestane-3, 16-diol. The configuration at C-22 and C-25 was determined by transformation into the known (22R, 25R)-5-solanidane-3-one. Application of the Ruschig method led to (25R)-22,26-imino-5-cholest-22(N)-ene-3, 16-diol.

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Solanum-Alkaloide. XVI. Mitteilung. — XV. Mitteilung:K. Schreiber undH. Ripperger, Tetrahedron Letters Nr.27, 9 (1960).     

The participation of kinins in the pathogenesis of early disturbances in the skin capillary permeability in localβ-ray irradiation

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The Kepler Problem from Newton to Johann Bernoulli

Summary Newton solved what was called afterwards for a short time the directKepler problem (le problème direct): given a curve (e.g. an ellipse) and the center of attraction (e.g. the focus), what is the law of this attraction ifKepler's second law holds?The problème inverse (today: the problème direct) was attacked system-atically only later, first byJacob Hermann, then solved completely byJohann Bernoulli in 1710 and followingBernoulli byPierre Varignon. How didBernoulli solve the problem? What method did he use for this purpose and which of his accomplishments do we still follow today?In the second part various questions connected to the first part are dealt with from the point of view, Conflict and Cooperation, suggested byJ. van Maanen to the participants of the Groningen conference.     

A study of the mechanism of polymyxin M inactivation

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Geminus and the concept of mean motion in Greco-Latin astronomy

Conclusion Geminus account of lunar motion in chapter 18 of hisIntroductio astronomiae is, in our view, an important contribution to Greco-Latin astronomy because, in attempting to reconstruct arithmetically (the parameters of) the Moon's motion in longitude, he undermines the task astronomers had hitherto set for themselves. This undermining of a commonly acknowledged view of the purpose of astronomy is articulated in a whole new set of questions concerning the nature and place of both observation and mathematical reasoning in the science of the heavens. Yet, one must not overlook the fact thatGeminus reconstruction also indicates resources for addressing these questions. Of these resources, the most powerful proved to be the idea that irregular motion could be quantified as a systematic departure from a mean motion, and the idea that observational data could be organized and structured by means of genetic arithmetical reconstructions.But, since we limit our attention to extant treatises and decline to speculate about works or parts of works that have not survived, we must say that it would takePtolemy to discern the new direction for astronomy thatGeminus opened up and to pursue it. In part, this involved straightening out the conflated conception of mean motion in chapter 18 — the qua arithmetic mean daily displacement can only be anapparent lunar motion in longitude and not one the Moonreally makes, but the same need not be true of the qua periodic mean daily displacement — and determining its proper relation to real and apparent planetary motion. Indeed,Ptolemy's genius lay, we think, in seeing that even though, in assimilating Babylonian astronomy, earlier and contemporary Greco-Latin writers betrayed a confused, inconsistent, and unsophisticated grasp of the proper role of arithmetic, geometry, and observation in astronomical argument [seeBowen 1994], the solution lay in a mathematical reconstruction of the observed celestial motions, in which mean motion played an essential role.     

Different effects of D-glucose anomers for respiration of bacterial germinated spores

Summary Effects of - or -D-glucose on the respiration of germinated spores (only germinated spores not including swollen spores and elongated spores) ofBacillus subtilis andB. megaterium were studied. In our conditions, net amount of oxygen consumed by 10¹⁰ germinated spores ofB. subtilis per min after addition of - or -D-glucose was 1.6 g or 6.6 g (/=4.13), while that byB. megaterium was 4.5 g or 6.8 g (/=1.51), respectively. However, the net amounts of oxygen consumed by 10¹⁰ vegetative cells per min after addition of - or -D-glucose were identical, forB. subtilis in both cases 443.0 g and forB. megaterium in both cases 604.4 g.     

Defensive steroids from a carrion beetle (Silpha americana)

Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15-hydroxyprogesterone (1, principal component), 5-pregnan-15-ol-3, 20-dione (2), 5-pregnan-3, 15-diol-20-one (3), 5-pregnan-7, 15-diol-3,20-dione (4), 5-pregnan-3, 7, 15-triol-20-one (5), 5-pregnan-16-ol-3,20-dione (6), and 5-pregnan-3, 16-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 g level.Paper No. 78 of the series: Defense Mechanisms of Arthropods. Study supported by NIH (Grants AI-02908, AI-12020). We thank Maura Malarcher and Maria Eisner for excellent technical help, and the Squibb Institute of Medical Research for samples of authentic reference compounds.     

Effect of biogenic amines on γ-amylase (acid α-glucosidase)

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IdentifyingY chromosome in interphase nuclei of the human brain

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