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1.
Summary An incipient form of tongue projection occurs inPhrynocephalus helioscopus, a generalized agamid lizard. We argue that this condition represents a functional intermediate between typical lingual prehension and chamaeleontid tongue projection, and that tongue projection evolved in chameleons by augmentation of ancestral mechanisms still operating in related, generalized lizards.  相似文献   

2.
Parthenogenetic reptiles: New subjects for laboratory research   总被引:1,自引:0,他引:1  
Summary Problems preventing establishment of laboratory colonies of parthenogenetic lizards have been solved. Now, productive colonies of these lizards, which have remarkably little genetic variation, can be readily established and used not only for research on parthenogenesis but also for many kinds of experiments for which reptile systems are desirable. Research colonies can provide valuable specimens while reducing the exploitation of natural populations.We thank José P. O. Rosado and George W. Foley for technical assistance and Richard G. Zweifel for specimens, ideas and support.  相似文献   

3.
Summary An electrophoretic investigation of 22 gene loci in a local sample of a widespread and ecologically extremely versatile gecko species has shown a low degree of heterozygosity, as is average in lizards and other vertebrates.  相似文献   

4.
Summary Splenectomy completely erased the PFC response to SRBC in lizards. In contrast, it has very little effect on the degree of MI to all doses ranging from 104 to 109, excepting the lowest dose, 103 SRBC.Supported by PL-480 (NIH) research grant, No. 01-077.Grateful to Madurai University for the award of Studentship during the tenure of the work and to Dr P. W. Askenase for the gift of capillaries used in this study.  相似文献   

5.
Summary The distribution of an SRIF-like substance in the brain of normal lizards (Lacerta muralis Laur.) has been determined. SRIF is shown to be present in neural cell bodies in the hypothalamic paraventricular nucleus, the hypothalamo-hypophysial tractus and the median eminence.Contrat INSERM, No. 74.1.444.35.  相似文献   

6.
A cryptic intermediate in the evolution of chameleon tongue projection   总被引:1,自引:0,他引:1  
K Schwenk  D A Bell 《Experientia》1988,44(8):697-700
An incipient form of tongue projection occurs in Phrynocephalus helioscopus, a generalized agamid lizard. We argue that this condition represents a functional intermediate between typical lingual prehension and chamaeleontid tongue projection, and that tongue projection evolved in chameleons by augmentation of ancestral mechanisms still operating in related, generalized lizards.  相似文献   

7.
Summary Results of a preliminary experiment indicate that injections of melatonin elicit testicular regression in male lizards having maximally recrudesced gonads at the outset of study.Supported by grants from the National Science Foundation (No. BMS74-04861), the American Philosophical Society (Penrose Fund), and the Biomedical Research program at Colorado State University.  相似文献   

8.
Summary Survival time ofDrosophila buzzatii adults on anOpuntia (prickly pear) medium was significantly longer than that of its nearest relativeD. serido. A significant difference was also found betweenD. buzzatii adults from two experimental populations, one of them fed onOpuntia rots for more than two years and another one kept on standardDrosophila medium for the same period of time. These results suggest that adult selection may be taking place in cactiphilicDrosophila in their natural habitats and could be responsible for the niche differentiation betweenD. buzzatii andD. serido.This work has been supported by the Comisión Asesora de investigación Científica y Técnica, Spain, by funds to project 4514/79 awarded to the third author.  相似文献   

9.
“To whom is the Consecration of Medal, Stature or even Pyramid more jusly due, than to … the late Illustraious Boyle? … for the happy Improvement of Otto Guericks Magdeburg Exhausterm and for his Profound and Noble Researches into all the abstruser Parts and Recesses of the most useful Philosophy … I have named the Illustrious Boyle, and fix his Trophy here.”

John Evelyn, Numismata, 1697.
  相似文献   

10.
Summary A yellow flavonoid pigment, which occurs as a companion of the lignan glycosides inPodophyllum peltatum L. andP. emodi Wall. has been identified as astragalin (=kaempferol-3-glucoside).

18. Mitt. über mitoschemmende Naturstoffe. 17. Mitt.:E. Schreier, Helv. chim. Acta47, 1529 (1964).  相似文献   

11.
Summary Fusarium oxysporum f. sp.carthami, a causative agent for the wilt disease of safflower (Carthamus tinctorius Linn.), has been shown to produce diacetoxyscirpenol, T-2 toxin, fusaric acid and lycomarasmin in artificial media. These substances produced disease syndromes, similar to those seen after the natural infection, when administered in healthy plants. Diacetoxyscirpenol and T-2 toxin have been detected in diseased safflower plants after inoculating with the wilt pathogen. This study is the first demonstration of vivotoxicity of diacetoxyscirpenol.  相似文献   

12.
Ohne Zusammenfassung Vorgelegt von B. L. van der Waerden Herrn Professor I. I. Schafranovsky, Berginstitut Leningrad, in Dankbarkeit gewidmet  相似文献   

13.
Communicated by H. Freudenthal  相似文献   

14.
Summary 112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms:Dipetalonema viteae, Fasciola hepatica; 3 of eggs:Ascaris suum, Toxocara canis, Schistosoma mansoni; and ofEchinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.  相似文献   

15.
Summary It is possible to show only H-antibodies in a latex test with a purified flagella suspension ofListeria monocytogenes. An antigen community betweenStaphylococcus aureus and flagella ofListeria could be excluded.  相似文献   

16.
Resumen EnTriticum durum Desf. (genomiosAB), el genomioA controla la sintesis de purotionina y el genomioB la de purotionina . Las especies diploides del grupoAegilops-Triticum sintetizan ó, pero no las dos. En numerosos aloploides de este grupo se observa la pérdida de la actividad sintética para la purotionina correspondiente a uno de los genomios.  相似文献   

17.
Summary A racemic intermediate in the total synthesis ofd, l-aldosterone, thed, l-20-oxo-pregnene derivative I, was converted by incubation with a mold hydroxylating in the 21-position into thed-20-oxo-21-hydroxy-pregnene derivative II, whereas thel-antipode of the starting material remained unchanged. This stereospecific microbiological reaction, comprising a separation of racemic modifications, represents the last remaining step in the synthesis of naturald-aldosterone.Other microbiological conversions of racemic steroids, dehydrogenation and hydrogenation, were also shown to proceed only with thed-enantiomer, leaving thel-form of thed, l-substrate intact.The advantages of this new microbiological method for the resolution of racemic modifications during the total synthesis of steroids are discussed.  相似文献   

18.
Taken together with my previous articles [77], [80] devoted to the history of finite random sums and to Laplace's theory of errors, this paper sheds sufficient light on the whole work of Laplace in probability. Laplace's theory of probability is subdivided into theory of probability proper, limit theorems and mathematical statistics (not yet distinguished as a separate entity). I maintain that in its very design Laplace's theory of probability is a discipline pertaining to natural science rather than to mathematics. I maintain also the idea that the so-called Laplacian determinism was no hindrance to applications of his theory of probability to natural science and that one of his utterances in this connection could have well been made by Maxwell's contemporaries.Two possible reasons why the theory of probability stagnated after Laplace's work are singled out: the absence of new fields of application and, also, the insufficient level of mathematical abstraction used by Laplace. For all his achievements, I reach the general conclusion that he did not originate the theory of probability as it is now known. Dedicated to the memory of my Father, Boris A. Sheynin (1898–1975), the first generation of the Russian revolution Cette inégalité [Lunaire] quoique indiquée par les observations, était négligée par le plus grand nombre des astronomes, parce qu'elle ne paraissait pas résulter de la théorie de la pesanteur universelle. Mais, ayant soumis son existence au Calcul des Probabilités, elle me parut indiqués avec une probabilité si forte, que je crus devoir en rechercher la cause.(P. S. Laplace (Théor. anal. prob., p. 361))  相似文献   

19.
Résumé Les protéines présentes dans les glandes salivaires deDrosophila pallidipennis ont été analysées grâce à une technique de microélectrophorèse discale. Les variations observées pendant le développement de la larve et de la jeune pupe on été comparées avec celles deDrosophila pseudoobscura. II semble que certaines variations soient le résultat de phénomènes communs à toutes les espèces du genreDrosophila.

Supported in part by grants No. GM-16 736-03 and No. FR-05 426-09 from the U.S. Department of Health, Education and Welfare. The author was a holder of a University of Texas predoctoral fellowship during the course of this investigation.  相似文献   

20.
Summary Danaus plexippus L. andDanaus chrysippus L. have been found to store pyrrolizidine alkaloids obtained from adult food plants and it is suggested that the alkaloids contribute to the unpalatability of the butterflies to potential predators.Acknowledgment. We thank Dr.C. C. J. Culvenor for rearing some of the butterflies andJ. M. Smith for plant collection. The plants were identified by the national Herbarium, Melbourne.  相似文献   

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