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1.
B. F. Binder W. S. Bowers P. H. Evans 《Cellular and molecular life sciences : CMLS》1991,47(2):199-201
Summary The insect anti-juvenile hormones precocene I and II (7-methoxy-2,2-dimethyl-2H-1-benzopyran and 6,7-dimethoxy-2,2-dimethyl-2H-1-benzopyran) were identified in three of nineNama (Hydrophyllaceae) species. Precocene I occurred inN. lobbii while precocene II occurred inN. hispidum, N. lobbii andN. sandwicense. N. hispidum contained the highest concentration (ca 0.5% dry weight) of precocene II, which was found in the leaves, stems, seed capsules, corolla, glandular trichomes, and seeds. In addition to the anti-juvenile hormone, insect juvenile hormone activity was detected in the organosoluble extracts ofN. rothrockii andN. sandwicense. N. sandwicense is the first plant discovered to contain compounds with both anti- and juvenile hormone activity. 相似文献
2.
R. Chênevert J. M. Perron R. Paquin R. Plante 《Cellular and molecular life sciences : CMLS》1981,37(1):32-33
Summary 4th instar nymphs ofSchistocerca gregaria exposed to precocene I and II by topical application metamorphosed precociously. The ED50 of both compounds were evaluated and, unexpectedly, precocene I was found to be more active than precocene II. All adultiforms were identical and in an advanced form.Acknowledgments. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada and the Ministère de l'Education du Québec. We are grateful to Gaston Grégoire for rearing the insects. 相似文献
3.
Summary A single topical application of precocene I or precocene II inhibits the normal process of vitellogenesis inDrosophila melanogaster. This effect is partly prevented by treatment with JH-11 or spontaneously reversible with time.This work was supported in part by NIH grants AI 15662 and GM 22711. 相似文献
4.
M. Samaranayaka-Ramasamy M. F. B. Chaudhury 《Cellular and molecular life sciences : CMLS》1981,37(9):1027-1029
Summary When adult femaleGlossina morsitans morsitans were treated with either precocene I or precocene II, females of the F1 generation, emerging from pupae of the 2nd, 3rd and 4th reproductive cycles failed to develop oocytes.Acknowledgments. The authors wish to thank Dr G. C. Unnithan for helpful discussions. 相似文献
5.
Summary
Oncopeltus fasciatus adults were treated with the antiallatotropin, precocene II and the circadian rhythms of feeding and mating behavior were monitored at 2-h intervals from lights on to lights off under 2 photoperiod regimes. Females ovariectomized as 5th instars were monitored for feeding and mating behavior at 2–3-h intervals from lights on to lights off as well. Neither precocene treatment nor ovariectomy was found to affect the mating or feeding behavioral rhythms under any photoperiod regime.Acknowledgment. This work was supported by a National Science Foundation Grant number PCM76-10560 to M.A.R. 相似文献
6.
P. D. Azambuja W. S. Bowers J. M. C. Ribeiro E. S. Garcia 《Cellular and molecular life sciences : CMLS》1982,38(9):1054-1055
Summary Precocene and analogs added to the meal of 4th instar larvae ofRhodnius prolixus were tested as antifeedants. While precocene II had a strong antifeedant effect (ED50=48 g/ml), the other compounds showed no drastic inhibition of feeding (ED50>140 g/ml). ATP, a phagostimulant, did not reverse the antifeedant action of precocene II. The mechanism of feeding inhibition is discussed.Acknowledgments. This research was supported by funds from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico, and National Science Foundation grants PCM-76-09647 and PCM-79-03245. 相似文献
7.
R. Chênevert J. M. Perron R. Paquin M. Robitaille Y. K. Wang 《Cellular and molecular life sciences : CMLS》1980,36(4):379-380
Summary Several analogs of precocene have been synthesized and evaluated as potential inhibitors of juvenile hormone onLocusta migratoria. Only 5,7-dimethoxy-2,2-dimethylchromene was active; its ED50 and LD50 were measured and compared to those of precocene I and II.Acknowledgments. This work was supported by grants from the Natural Sciences and Engineering Research Council of Canada and the Ministère de l'Education du Québec. We are grateful to Gaston Grégoire for rearing the insects. 相似文献
8.
Summary When precocene II was applied to the fourth instar milkweed bug, there was a significant decrease in acid phosphatase activity in the hemolymph at the 40%, 50%, 60%, and 70% time periods in the stadium. 相似文献
9.
Summary Transection of the nervous connections between the brain and the corpus allatum (CA) inOncopeltus fasciatus does not alter the susceptibility of the CA to precocene II in vivo.The authors wish to thank Patricia Ferugia for rearing the insects; Dr D. Soderlund, Department of Entomology, New York State Agricultural Experiment Station for helpful discussions; and Dr A.O. Lea, Department of Entomology, University of Georgia for technical advice. To whom reprint requests should be addressed 相似文献
10.
P. J. Müller P. Masner Maria Kälin W. S. Bowers 《Cellular and molecular life sciences : CMLS》1979,35(5):704-705
Summary Corpora allata fromOncopeltus fasciatus incubated in vitro in medium containing 10–5.35 M (1 g/ml) of precocene II lose their ability to secrete juvenile hormone when reimplanted into last instar larvae.Acknowledgments. We thank Mr K. Dorn, Mrs L. Dolezal, Mrs V. Nötzli-Graf, Mr K.H. Trautmann and Mr A. Schuler for technical help, Dr W. Vogel and Dr A. Dübendorfer for valuable discussions. 相似文献
11.
Summary 50–100% of the 2nd, 3rd and 4th instar nymphs ofSchistocerca gregaria exposed to precocene 2 by contact method metamorphosed precociously from the instar treated. The corpora allata of the precocious adults were degenerate. Topical application of a juvenile hormone analogue (ZR-512) induced in the precocious adults the colouration characteristic of sexually mature adults.This research was supported by the N.S.E.R.C. grant No.A4669.We thank Dr G. B. Staal, Zoecon Corporation, Palo Alto, California, for the generous gift of precocene 2 and ZR-512, M. Hota for rearing the insects, R. G. Long, for the photographs, and Jann Aitken for technical assistance. 相似文献
12.
H. Schooneveld 《Cellular and molecular life sciences : CMLS》1979,35(3):363-364
Summary Precocene II causes an irreversible regression of corpora allata in young 4th instar nymphs of the migratory locust. Within 2 h after application, the cells collapse. Cell fragments are subsequently phagocytosed by haemocytes.Acknowledgment. Thanks are due to Dr G. B. Staal of Zoecon Corporation for the gift of precocene II, and to the Department of Virology for the use of the electron microscope facilities. 相似文献
13.
W. F. Walker 《Cellular and molecular life sciences : CMLS》1977,33(11):1539-1541
Summary The diurnal feeding rhythm of female milkweed bugs was damped when fed nonhost seeds. Juvenoid treatment partially restored the normal rhythm. Precocene II-treated milkweed seed-fed females fed arrhythmicly during the light phase without reduced total feeding activity. This effect was largely prevented by simultaneous treatment with JH III.I thank Dr Judith H. Willis, Univ. of Illinois, for providing facilities, Meyer Schwartz of ARS, USDA, Beltsville, MD, USA, for providing the precocene II, and Dr W. S. Bowers, formerly of ARS, USDA, Beltsville, MD, for supplying the juvenoid. This work was supported in part by grant AG-00248 from the National Institutes of Health to J. H. Willis. 相似文献
14.
I. Kiss A. Fodor T. Timar S. Hosztafi P. Sebok T. Torok E. Viragh M. Berenyi 《Cellular and molecular life sciences : CMLS》1988,44(9):790-792
Summary Structure-optimization studies of C-5-C-8-substituted precocene (P) analogues revealed that 1) compounds disubstituted asymmetrically at C-6, C-7 had an anti-allatal effect only if the C-6 side-group was shorter than that at C-7, 2) in the case of C-5, C-7 disubstitution, activity was enhanced by Me at C-5 whereas MeO caused inactivity. Effects of various other substitutions are also discussed. 相似文献
15.
Summary It has been tested whether juvenile hormone plays a role in the larval-adult transformation of lateral oviducts in the milkweed bug. The transformation is ecdysteroid-dependent, as was reported previously2. Application of precocene or juvenile hormone III proved that the absence of juvenile hormone is required.Acknowledgments. This work was supported by a grant (Do 163/91) of the DFG. We thank Ms C. Friederichs for excellent technical support. 相似文献
16.
Summary The corpora allata of adult and 5th instar nymphs of the migratory locust exhibit several ultrastructural alterations after lindane intoxication. The type of cell degeneration observed here is very similar to ultrastructural changes obtained after the administration of precocene. 相似文献
17.
A. A. Rokosu T. O. Akunnaezili P. A. Ikhile 《Cellular and molecular life sciences : CMLS》1982,38(1):78-79
Summary Alkaline phosphatases (ALP I and ALP II), isolated and purified fromAspergillus niger exhibited broad specificity towards a wide variety of substrates, and consistently ALP II was more active than ALP I. It is possible that the difference in levels of activity of the 2 enzymes may be of physiological importance in the mycelia ofA. niger. 相似文献
18.
Summary Acid phosphatase ofEimeria tenella oocysts (Peak II) was purified 77-fold with a recovery of 26% using protamine sulfate precipitation, DEAE-cellulose chromatography and Sephadex G-200 gel filtration. This enzyme occurs in multiple forms as indicated by two peaks which can be separated by DEAE-cellulose chromatography and polyacrylamide gel electrophoresis. The partially purified enzyme has optimal activity at pH 4.5. With p-nitrophenyl phosphate the Km and Vmax values for (Peak II) were 25 mM and 1.57 mol/min/mg protein, respectively. The enzyme (Peak II) ist strongly inhibited by Hg++, Cu++, iodoacetamide, fluoride and molybdate. Tartrate and other divalent metal ions have no effect on enzyme activity. The partially purified Peak II phosphatase is not a glycoprotein as it is not absorbed on concanavalin-A Sepharose and its treatment with bacterial neuraminidase does not alter its elution profile through DEAE cellulose. 相似文献
19.
Summary The protozoanCrithidia fasciculata contains two different ribonuclease H activities. These enzymes display similar physical and biochemical characteristics to their homologues in higher eukaryotes, for instance calf thymus class I and class II ribonuclease H. Class I ribonuclease H of lower and higher eukaryotes can be activated by Mg2+- and Mn2+- ions. However, the presence of Mn2+-ions is inhibitory for the Mg2+-dependent class II ribonuclease H activity ofCrithidia fasciculata and calf thymus. The protozoan class I-homologue enzyme appears to be serologically related to the class I ribonuclease H of calf thymus. 相似文献
20.
S. S. -L. Li 《Cellular and molecular life sciences : CMLS》1980,36(5):524-527
Summary 2 different lectins have been purified from the seeds ofMomordica charantia by gel-filtration and ion-exchange chromatography. These 2 lectins appear to be composed of 2 subunits of 26,000 daltons. Protein fraction I, but not II, showed agglutinating activity toward human type-O red blood cells. The amino acid compositions and amino-terminal sequences of these two homologous proteins are quite different.Acknowledgment. The skillful assistance of Ms M. Diane Forde is greatly acknowledged. Part of this work was supported by NIH grants CA18621 and AI09810 when the author was at Mount Sinai School of Medicine. 相似文献