Inhibition ofPhysarum mitochondrial division by cytochalasin B

Summary The mitochondrial division ofPhysarum is inhibited by cytochalasin B. Dumbbell-shaped dividing mitochondria become spherical bodies by this inhibitor. These results suggest that contractile proteins are essential for the mitochondrial division.     

Blockade of the hydrosmotic effect of vasopressin by cytochalasin B

Résumé La cytochalasine B dissocie les effets hydrosmotique et natriférique de la Pitressine sur la vessie de crapaud, en bloquant le transport d'eau sans pour autant modifier la stimulation du transport de sodium. Les interactions possibles entre le macrolide, les microfilaments et les altérations de perméabilité sont discutées.     

The inhibition of amphibian ovulation in vitro by cytochalasin B

Zusammenfassung Cytochalasin B (5 g/ml) verhindert in vitro vollständig die inRana pipiens undHyla regilla durch Gonadotropinbehandlung stimulierte Ovulation, während die Meiose weiter abläuft. Diese Resultate werden mit früheren Beobachtungen einer ähnlichen Empfindlichkeit der Follikelzellenbewegung bei Seesternen verglichen. Ein für Echinodermen und niedere Wirbeltiere gemeinsamer Follikelmechanismus für die Austreibung des Ovarialeies aus dem Ovar wird vorgeschlagen.

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Supported by funds provided for biological and medical research by State of Washington Initiative Measure No. 171. The competent assistance ofP. Pendergrass andM. Vandenbark is gratefully acknowledged.     

Action of ACTH,cAMP and cytochalasin B on steroid production by Y-1 mouse adrenal tumor cells in culture

Summary Continued incubation of Y-1 mouse adrenal tumor cells with adrenocorticotrophic hormone (ACTH) or with dibutyryl-3,5-cyclic adenosine monophosphate (dbcAMP) resulted in an initial increase and a subsequent decrease in steroidogenesis. ACTH-or dbcAMP-stimulated steroidogenesis was inhibited by cytochalasin B (CB) to approximately the same extent during the entire period of incubation; CB inhibition of the ACTH response was reversible.Supported in part by NTSU Faculty Research grant No. 34711, and NIA No. AG01055-02A1.Acknowledgment is made for the assistance of L. Hershberger, J. Youngblood and V. Dang; K. Mrotek, K. Johansson and M. Donahue were editors.     

The morphology of cytoplasts and karyoplasts produced by cytochalasin D

Summary The denucleation of L cells and human lymphocytes in suspension was carried out by incubation with cytochalasin D25 and 50 g/ml and with ultracentrifugation over a discontinuous Ficoll gradient. Ultrastructural examination of the separate layers confirmed the presence of the anucleate cytoplasm (cytoplasts) with intact membrane and the separated nuclei (karyoplasts).This work was supported by a grant from the National Cancer Institute of Canada.     

Rotation and first reversion in theOctopus embryo — A case of gradual reversal of ciliary beat

Zusammenfassung Cilien des äusseren Dottersackes versetzen Octopoden-Embryonen in Rotation innerhalb ihrer Eihülle. Die erste Umdrehung oder «Blastokinese» ist die Folge einer einmaligen, innert Stunden ablaufenden Schwenkung der Cilienschlagrichtung um 180°.     

The morphology of cytoplasts and karyoplasts produced by cytochalasin D.

The denucleation of L cells and human lymphocytes in suspension was carried out by incubation with cytochalasin D25 and 50 microgram/ml and with ultracentrifugation over a discontinuous Ficoll gradient. Ultrastructural examination of the separate layers confirmed the presence of the anucleate cytoplasm (cytoplasts) with intact membrane and the separated nuclei (karyoplasts).     

Comparison of the effects of illumination on the melanophores of intact and eyestalkless fiddler crabs,Uca pugilator,and inhibition of the primary response by cytochalasin B

Summary Approximately 100 times more illumination is required to produce pigment dispersion in the melanophores of eyestalkless fiddler crabs (Uca pugilator) than in the melanophores of intact crabs. The pigment in melanophores of isolated legs will normally disperse in response to irradiation, but this response is inhibited by cytochalasin B.This investigation was supported by a Faculty Research Grant from Western Kentucky University toT. P. Coohill and by Grant No. GB-27497 toM. Fingerman from the National Science Foundation.     

Comparison of the effects of illumination on the melanophores of intact and eyestalkless fiddler crabs, Uca pugilator, and inhibition of the primary response by cytochalasin B.

Approximately 100 times more illumination is required to produce pigment dispersion in the melanophores of eyestalkless fiddler crabs (Uca pugilator) than in the melanophores of intact crabs. The pigment in melanophores of isolated legs will normally disperse in response to irradiation, but this response is inhibited by cytochalasin B.     

Alterations of the erythrocyte membrane caused by fluorinated dinitrobenzenes

Zusammenfassung Inaktivierung der Acetylcholinesterase in der Erythrozytenmembran mit 1-Fluor-2,4-dinitrobenzol und 1,5-Difluor-2,4-dinitrobenzol konnte durch blutgruppenspezifische Antikörper nicht beeinflusst werden. Nach Difluordinitrobenzol-Behandlung zeigten die Blutkörperchen Verlust der Agglutinabilität und die Membranen eine Herabsetzung ihrer Absorptionsfähigkeit für homologe Antikörper.

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This work was supported by research grant No. HD 01461 from the National Institutes of Health, U.S.P.H.S.     

Chemical structure of circulin B

Zusammenfassung Es wird über die Strukturaufklärung von Circulin B, einem Antibiotikum ausBacillus circulans ATCC 14040, berichtet, dem die Formel des Schemas 2 zukommt.     

Some observations on carotenoid synthesis by the algaChlorella vulgaris

Zusammenfassung WirdChlorella vulgaris in einem Medium, das Glukose, Pepton und Mineralsalze enthält, gezüchtet, so synthetisiert sie sowohl in Licht wie im Dunkeln -Carotin, Lutein, Violaxanthin und Neoxanthin. Das Wachstum im Dunkeln beträgt jedoch nur 1/6 von demjenigen im Licht. Die Carotinoide verschwinden aus alten Lichtkulturen, werden aber in alten Dunkelkulturen weiter synthetisiert. Diphenylamin hemmt das Wachstum dieses Organismus bei einer Konzentration von 1/280 000 vollständig.     

The X-ray analysis of the structure of rifamycin B

Zusammenfassung Die molekulare Struktur des Rifamycins B wurde durch Röntgen-Strukturanalyse der Kristalle seinesp-Jodanilids bestimmt. Die Ergebnisse bestätigen die vor kurzem auf chemischem Wege aufgeklärte Konstitution und liefern darüber hinaus interessante Auskunft über die Konfiguration und Konformation der Rifamycine.

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A brief preliminary report on this structure has been read at a meeting of the Accademia Nazionale dei Lincei, Rome, on December 14, 1963².