首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
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.  相似文献   

2.
Summary Evidence of hybridization between the ground squirrels,Spermophilus tridecemlineatus andS. mexicanus is presented on the basis of chromosomal and protein data. The hybrids produced appear to be completely interfertile. Based on the evidence of hybridization and the recent reestablishment of contact between these two species, they are considered to be semispecies.Supported by Faculty Research Grant No. 34925 from North Texas State University awarded toZimmerman.  相似文献   

3.
Zusammenfassung Kreuzungsversuche und elektrophoretische Analyse der Erythrocytenesterase bei der MausPeromyscus truei zeigten, dass die Homozygoten je eine Enzymbande mit unterschiedlichen Beweglichkeiten aufweisen, während bei den Heterozygoten beide Enzymbanden vorkommen, was mit der Annahme der Abspaltung von zwei kodominanten Allelen eines einzigen autosomalen Locus übereinstimmt.

Supported by Faculty Research Grant No. 35064 from North Texas State University awarded toZimmerman.  相似文献   

4.
Zusammenfassung Die blauen ozeanischen Cirripedien,Lepas fascicularis, speichern Karotinoide in Eiern, Eingeweiden und den meisten übrigen Geweben in den folgenden ungefähren Konzentrationen: 5:2:1 mg/100 g. In jeder Art von Gewebe ist Astaxanthin das Hauptkarotinoid, welches meist in Form des blauen Chromproteins vorliegt. Kleinere Mengen von Karotin und etwas mehr Xanthophylle kommen in den Eingeweiden, nicht aber in den reifen Eiern vor.

Contribution from the Scripps Institution of Oceanography. This research was supported by Research Grant No. GB-5332X from the National Science Foundation. We are indebted also toJoanne Rhoads andP. Wiebe for donating some of the fresh barnacle specimens, and to Dr.W. A. Newman for his help and information concerning the biology and dissection of this barnacle.  相似文献   

5.
Résumé L'étude des chromosomes somatiques d'une lamproie de l'Amérique du Nord,Ichthyomyzon gagei Hubbs and Trautman montre que l'equipement chromosomique diploide est composé de 164 chromosomes, qui sont acrocentriques ou télocentriques et très petits (moins de 3,5µm). Il n'y a pas de différences entre le karyotype deI. gagei et celui deLampetra aepyptera (Abbott). Les rapports deI. gagei avec les autres lamproies et l'évolution du caryotype sont examinés.

This research was supported by Samford University Research Fund, Grant No. 20, toHowell.  相似文献   

6.
Zusammenfassung Funktionsdynamik von Gehirn-Norepinephrin (NE) in kastrierten und scheinkastrierten männlichen, geschlechtsreifen (C57Br/6J)-Mäusen wurde nach 13 Monaten Isolierung untersucht. Kastrierung bewirkt starken Abfall des ursprünglichen Niveaus und der Stoffwechselgeschwinddigkeit von NE.

Supported in part by a USPHS Predoctoral Fellowship toB. K. Bernard and NIMH Grant No. MH 15352 toR. M. Paolino.  相似文献   

7.
Résumé On a évalué des effets de plusieurs agents antinéoplastiques sur la consommation d'oxygène des lymphocytes leucémiques L1210 de la souris et on les a mis en corrélation avec l'activité antitumorale de chaque composition. Cette étude indique qu'il n'y a pas de rapport apparent entre ces deux paramètres de l'action des drogues.

Acknowledgments: The authors wish to express their appreciation to Dr.R. M. Folk of Battelle's Columbus Laboratories for his consultation and advice and toMelanie Crossin for her technical assistance.

Supported by Grant No. AM-HE-12084-15 from the National Institutes of Health, Bethesda, Maryland, and Grant No. 7132 from The Ohio State University General Research Support Fund.  相似文献   

8.
Summary A study was made of the effect of daily administration of kanamycin (400 mg kg–1) on the hearing of Wistar albino and Lister hooded (pigmented) rats, which had been conditioned to discriminate an acoustic signal. In all animals except one, the drug caused severe, permanent hearing impairment and there was no difference between albino and pigmented rats in onset or degree. Other work has suggested a mediatory role for melanin pigment in such drug ototoxicity but the significance of this must be questioned in view of the failure to find any differences in functional deficit.This work was supported by a Fellowship toE. S. Harpur from the Department of Health and Social Services (Northern Ireland).  相似文献   

9.
Zusammenfassung Die erstmalige Synthese des Peptidhormons 8-Glutamin-Oxytocin wird beschrieben. Das synthetische Peptid ist mit einem anderen Peptid des Dornhaies von noch ungeklärter Struktur nicht identisch.

(a) This work was supported in part by a Studentship (to J.W.M.B.) and a Grant (to M.M.) from the Medical Research Council of Canada, an award (to T.C.W.) from the Banting Research Foundation, a National Science Foundation Grant No. GB 4932 and a General Research Support Grant to Columbia University from the National Institutes of Health. (b) An abstract of this work was presented at the 5th Annual Meeting of the Federation of European Biochemical Societies, July, 1968; M.Manning, T. C.Wuu, J. W. M.Baxter and W. H.Sawyers, FEBS 1968 Meeting, Prague, Abstr.824, p. 206.  相似文献   

10.
Zusammenfassung Feststellung eines Tag-Nacht-Rhythmus der Konzentration von Adrenalin und Noradrenalin in den Nebennieren von Ratten.

Supported by U.S.P.H.S. Grant No. NS-08929.

Acknowledgements. We would like to express our appreciation toLaurel Patterson andJacqueline Skaggs for their excellent technical and secretarial assistance.  相似文献   

11.
Zusammenfassung Fe59-Aufnahme in Kaninchen-Retikulozyten ist durch erhöhte Werte des Isotops in der wasserlöslichen Fraktion und erniedrigten Werten im Stroma der Katzen-Retikulozyten charakterisiert. Bei Kaninchen- und Katzen-Erythrozyten ist dieses Verhältnis umgekehrt. Na+ und K+ aktivierte ATPase zeigt die höchsten Werte in den Kaninchen-Retikulozyten.

Supported by National Science Foundation Grant No. GB-2295 and Public Health Service Grant No. AM 09069 and by a NIH Predoetoral Fellowship, No. 5-Fl-GM-29843 toW. C. Wise.  相似文献   

12.
Zusammenfassung Eine Voruntersuchung der Insektengruppe Lepidoptera auf anti-tumor-aktive Stoffe führte zu einer detaillierten chemischen Prüfung der aus Asien stammenden SchmetterlingeCatopsilia crocale Cramer (Pieridae) undPieris rapae cruavora. Ein bedeutender Teil der Anti-Tumor-Aktivität scheint ihren Ursprung in der chemischen Substanz Isoxanthopterin zu besitzen.

The present contribution represents Part XXVII of the series Antineoplastic Agents. For Part XXVI refer toG. R. Pettit, J. F. Day, J. L. Hartwell andH. B. Wood, Nature, Lond.227, 962 (1970).

This investigation was supported by Public Health Service Research Grants No. CA-10612-01 to No. CA-10612-04 from the National Cancer Institute, and was presented in part at the American Chemical Society Meeting, Washington, D.C., September 1971. We are also grateful to the National Science Foundation for financial assistance (Grant numbers GB-4939 and GB-6979) used in obtaining the Atlas CH-4B and SM-1B mass spectrometers employed in this study.  相似文献   

13.
Zusammenfassung Eine dosisabhängige Steigerung der Körpertemperatur wurde erzielt, wenn Pyrogen-Substanzen aus verschiedenen gram-negativen Bakterienstämmen stereotaktisch in den Hypothalamus nicht narkotisierter Affen injiziert wurden.

Supported in part by USA Office of Naval Research Contract No. N00014-67-A-0026-0003 and National Science Foundation Grant No. GB 7906. We are indebted toP. Curzon for his valuable technical assistance, and to Dr.R. L. Somerville for preparing the pyrogens.

Post-Doctoral Fellow supported by NIH Health Sciences Advancement Award No. PHS 5-S04-FR-0615.

NIH Pre-Doctoral Fellow in Neurobiology.  相似文献   

14.
Zusammenfassung Andauernde ACTH-Behandlung beeinflusst sowohl Vermeidungs- als auch Fehlerkomponenten im Zweiwahl-Y-Labyrinthtest. Die Einwirkungen waren von der Intensität des Elektroschocks wie auch von der Reaktionsfähigkeit der Tiere abhängig.

This work was supported by Medical Research Council Grant No. MA 1746. Some of the work was done while the first author held a pre-doctoral terminal year grant from the USPHS and while the second author held a Research Career Award from the Canadian Association for Retarded Children. We are indebted toSusanna Kertesz for help in running the subjects in these studies. Requests for reprints should be sent to Dr.J. A. Corson, Allan Memorial Institute, 1033 Pine Avenue West, Montreal 112 (P.Q., Canada).  相似文献   

15.
Summary In tadpoles ofRana temporaria, the light threshold for the pigment dispersal of melanophores was determined. The darkening reaction of previously dark-adapted animals is not affected by removal of the lateral eyes and starts with illumination of about 0.01 lm/m2. This is about 2 log units below the threshold of the direct effect of light on tailfin-melanophores inXenopus tadpoles and about 2 log units above the light threshold of the steady discharge of the exposed diencephalon in adult frogs. The finding suggests that in tadpoles the pineal organ controls the function of melanophores.  相似文献   

16.
Summary The acute administration of morphine, alcohol or dopamine results in a pronounced suppression of the convulsions produced by alcohol in mice. The suppressive action of morphine on alcohol withdrawal in the mouse apparently is not a product of morphine intoxication, but rather to some other specific interaction between alcohol and morphine in the central nervous system. The conclusion suggest that dopamine may play a significant role as a modulator in convulsions produced during alcohol withdrawal.Dr.Kenneth Blum is Associate Professor in Pharmacology at The University of Texas Health Science Center at San Antonio and a Career Teacher in Drug Abuse and Alcoholism under a grant number 1-TO1-DA00290-01 from the National Institute on Drug Abuse.Acknowledgments. Our thanks are due toB. Wiggins, R. Marin andS. Elston for their excellent technical assistance. Research funded in part by Air Force Grant No. AFOSR-71-2075.  相似文献   

17.
Zusammenfassung Aus der PflanzeHelenium autummnale (Familie compositae) wurde ein alkolischer Extrakt gewonnen, der cytotoxische und antileukämische Aktivität zeigte und die Helenalin (I) als wirksame Komponente enthielt. Die Behandlung von Mäusen, die Träger von P 388 lymphocytischer Leukämie waren, ergab eine beachtliche (T/C 220) Verlängerung ihrer Lebenserwartung. Die Substanz zeigte ausserdem einen wachstumshemmenden Einfluss auf das Walker 256 Karzinom. Helenalin ist das erste Sesquiterpen vom Pseudoguaianolid Typ, welches in vivo eine solche antineoplastische Aktivität zeigt.

For part 31, refer toG. R. Pettit, P. Traxler andC. P. Pase, Lloydia36, in press (1973).

This investigation was supported by Public Health Service Research Grants No. CA-10612-01 to No. CA-10612-04 from the National Cancer Institute and was performed pursuant to contract No. NCI-C-71-2308 with the Division of Cancer Treatment, National Cancer Institute, Department of Health, Education and Welfare. A grant from the C.S.I.R. (South Africa) to G.M.C. is also gratefully acknowledged. In addition, we are indebted to Dr.L. Johnston for identifying theHelenium autumnale, toBetty J. Abbot and her colleagues at the National Cancer Institute, for the biological studies, and toJ. F. Day for assisting with both the laboratory scale and preparative scale plant extraction procedures.  相似文献   

18.
On December 13, 1679Newton sent a letter toHooke on orbital motion for central forces, which contains a drawing showing an orbit for a constant value of the force. This letter is of great importance, because it reveals the state ofNewton's development of dynamics at that time. Since the first publication of this letter in 1929,Newton's method of constructing this orbit has remained a puzzle particularly because he apparently made a considerable error in the angle between successive apogees of this orbit. In fact, it is shown here thatNewton's implicitcomputation of this orbit is quite good, and that the error in the angle is due mainly toan error of drawing in joining two segments of the oribit, whichNewton related by areflection symmetry. In addition, in the letterNewton describes quite correctly the geometrical nature of orbits under the action of central forces (accelerations) which increase with decreasing distance from the center. An iterative computational method to evaluate orbits for central forces is described, which is based onNewton's mathematical development of the concept of curvature started in 1664. This method accounts very well for the orbit obtained byNewton for a constant central force, and it gives convergent results even for forces which diverge at the center, which are discussed correctly inNewton's letterwithout usingKepler's law of areas.Newton found the relation of this law to general central forces only after his correspondence withHooke. The curvature method leads to an equation of motion whichNewton could have solvedanalytically to find that motion on a conic section with a radial force directed towards a focus implies an inverse square force, and that motion on a logarithmic spiral implies an inverse cube force.  相似文献   

19.
Summary Tetrahymena size distribution during the cell cycle was analyzed by means of radioautography with the aid of a sonic-digitizer, and a computer. The study demonstrates that as the organism ages and passes through the various cell cycle phases the volume distribution of the organisms in each phase remains lognormal.Acknowledgments. This work was supported by a research grant from Gtiftung Volkswagenwerk No. 112273 toA. Ron. The authors wish to acknowledge the technical help of Mrs.O. Horovitz and MissS. Urieli, as well as the expert photomicrography of Mrs.E. Salomon.  相似文献   

20.
Zusammenfassung Es wird über die Isolierung und Charakterisierung der Titelverbindung (Gly-l-Pro Lactam, I) aus dem SeesternLuidia clathrata berichtet. Die Kristallstruktur dieses Dioxopiperazinderivats wurde ermittelt. Der Piperazinring liegt in der Wannen-Konformation vor.

This investigation was supported by contract No. NIH-71-2308 from Chemotherapy, National Cancer Institute, National Institutes of Health and by Public Health Service Research Grant No. CA-11451-03 from the National Cancer Institute. The authors also gratefully acknowledge support from the National Science Foundation which provided the X-ray diffractometer and mass spectrometer. For the previous contribution of this series seeG. R. Pettit, R. H. Ode andT. B. Harvey, III, Lloydia,36 (1973).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号