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Summary (–)--Fenchol, a compound occurring in plants but not heretofore reported to occur in an animal product, was isolated from volatiles released by adult male Mediterranean fruit flies,Ceratitis capitata Wiedemann, with the male's previously identified sex pheromones. It neither attracts females nor synergizes the pheromones, and its function remains unknown.The editors do not hold themselves responsible for the opinions expressed in the authors' brief reports. — Les auteurs sont seuls responsables des opinions exprimées dans ces brèves communications. — Für die Kurzmitteilungen ist ausschliesslich der Autor verantwortlich.—Per le brevi comunicazioni è responsabile solo l'autore. — . — Solo los autores son responsables de las opiniones expresadas en estas communicationes breves.Mention of a proprietary product in this paper does not constitute a recommendation or an endorsement of the product by the US Department of Agriculture.Acknowledgments. We thank C. Harding for assistance with extractions and fractionations, R.M. Waters for spectral analyses, M.S. Fujimoto and H. Higa for collecting the volatiles and conducting laboratory and cage bioassays, and T. Urago and S. Nakagawa for conducting the field tests.  相似文献   

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Summary The vast majority of oil-droplets in the dark and light-adapted retinal twin-cones ofPoecilia reticulata is of the matrix-type. In bright light (day light+overhead strip light) there occurs in some regions a very pronounced numerical change from matrix to cristate-type, whereas other regions remain unaffected. The functional significance of these differences is discussed.  相似文献   

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-Spermophilus brunneus . , 13 18 ,S. brunneus S. townsendii mollis (2n=38) , , ; ;S. brunneus . S. brunneus , Spermophilus.

Supported by National Science Foundation Grants No. GB32114X and No. GB 29131X, and the Sprague Foundation. We thankD. Pozin for technical assistance.  相似文献   

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Summary Morphological transformations are often describable by simple series kinetic models,AB, ABC, etc., which allow assessment of the rates of interconversion of the distinguishable shapes or forms present and their probabilities of occurrence at various points in time, thus providing a means for kinetic comparisons with biochemical measurements of the molecular-level reactions that cause the transformations. When changes in cell morphology are followed turbidimetrically, the real-time progress curves can be simulated by fitting the data to a form of Beer's law for scattering by mixtures in which the species concentrations change with time in accordance with the chosen kinetic scheme. Because many even relatively large cells are mostly water, classical light scattering theory can be used to interpret the turbidimetric data in terms of simple geometrical models ofaverage cell size and shape suggested by microscopic examination. Two examples are briefly considered, the stimulus-induced changes in blood platelet shape and apparent size and their correlation with cytosolic-free calcium, and apparent swimming motion exhibited by neutrophils in suspension.What do you know about this business? the King said to Alice. Nothing, said Alice. Nothing whatever? persisted the King. Nothing whatever, said Alice. That's very important, the King said. Lewis Carroll (1865), in Alice's Adventures in Wonderland  相似文献   

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G-protein signaling: back to the future   总被引:14,自引:0,他引:14  
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 Gq 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  相似文献   

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Summary 6-Methoxy-9,10 -pregna-4,6-diene-3,20-dione inhibites the 4-3-oxosteroid-5-reduction in microsomes and the 4-3-oxosteroid-5-reduction in the soluble fraction of male rat liver. The 3- and 3-hydroxysteroid dehydrogenase are not inhibited by this substance.

Diese Arbeit wurde von der Firma Hoffmann-La Roche, Basel, unterstützt.  相似文献   

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- . Ovis musimon (2n=54) O. orientalis (2n=54) - - -O. canadensis mexicana (2n=54) O. musimon x O. canadensis 12 - . 2 27 . - .

Supported by National Science Foundation Grant no. GB 32114X and the Sprague Foundation. We thank Dr. T. C. Hsu for assistance in making the chromosome preparations and for advice and encouragement. The Trustees of the Rachelwood Wildlife Research Preserve generously allowed the biopsy of specimens of their custody. Mr.Arthur Popham kindly provided the specimens from Iran while Dr.R. M. Robinson obtained biopsies from the desert sheep.  相似文献   

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