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171.
For up to three days after being treated with the precocene analogue 6-methoxy-7-ethoxy-2,2-dimethylchromene, adult green peach aphids (Myzus persicae) gave birth to offspring (alate and apterous virginoparae, males) which underwent precocious metamorphosis. Only a few precocious gynoparae and no precocious oviparae were recorded. The precocious aphids became adultoid in the third or fourth-instar as a result of corpus allatum destruction. They were able to develop mature embryos, but could not deposit them because of incomplete differentiation of the reproductive tract. The treatment did not induce the production of alate virginoparae in the experimental clone of Myzus persicae. However, a few males were born late in the reproductive sequence of treated apterae. The corpora allata of the treated adults appeared on histological examination to be unaffected by precocene. 相似文献
172.
The genetic effects of MNNG, 4NQO and ICR-170 have been compared on 5 different UV-sensitive strains and a standard wild-type strain of Neurospora crassa with regard to inactivation and the induction of forward-mutations at the ad-3A and ad-3B loci. Whereas all UV-sensitive strains (upr-1, uvs-2, uvs-3, uvs-5 and uvs-6) are more sensitive to inactivation by MNNG and ICR-170 than wild-type, only uvs-5 shows survival comparable to wild-type after 4NQO treatment, all other strains are more sensitive to 4NQO. In contrast to the effects on inactivation, a wide variety of effects were found for the induction of ad-3A and ad-3B mutations: higher forward-mutation frequencies than were found in wild-type were obtained after treatment with MNNG or 4NQO for upr-1 and uvs-2, no significant increase over the spontaneous mutation frequency was found with uvs-3 after MNNG, 4NQO or ICR-170 treatment; mutation frequencies comparable to that found in wild-type were obtained with uvs-6 after MNNG, 4NQO or ICR-170 treatment and with upr-1 after ICR-170 treatment. Lower forward-mutation frequencies than were found in wild-type were obtained with uvs-2 after ICR-170 treatment and with uvs-5 after MNNG, 4NQO or ICR-170 treatment. These data clearly show that the process of forward-mutation at the ad-3A and ad-3B loci is under genetic control by mutations at other loci (e.g. upr-1, uvs-2, uvs-3, uvs-5 and uvs-6) and that the effect is markedly mutagen-dependent. 相似文献
173.
Sterols were isolated from ten mushrooms, Hygrocybe punicea, Lampteromyces japonicus, Leucopaxillus giganteus, Lentinus edodes, Flammulina velutipes, Amanita caesarea, Coprinus atramentarius, Russula foetens, R. nigricans and R. senecis. The compositions of the sterol fractions were determined by GLC, combined GC/MS, and 1H NMR. Ergosterol was present in all the mushrooms. Other sterols found were 5α-cholest-7-en-3β-ol and ergosta-5,7-dien-3β-ol. Ergosta-5,8,22-trien-3β-ol was isolated from F. velutipes. 相似文献
174.
A new alkaloid, 3-methoxy-4,6-dihydroxymorphinandien-7-one, and norsinoacutine have been isolated from extracts of Croton bonplandianum. 相似文献
175.
Dry lettuce (Lactuca sativa L.) seeds (achenes) contain -galactosidase (EC 3.2.122) at a level which is maintained in the imbibed dormant state in darkness. Both red light (R) and gibberellic acid promote an increase in enzyme activity several hours prior to the completion of germination. Germination and enzyme activity are not essentially linked, however, for the latter can increase while the former is inhibited. -Galactosidase activity increases within the cotyledons and the endosperm following R stimulation, but the axis is essential to perceive the stimulus and to promote and maintain the increase in enzyme activity. A diffusible factor (or factors) is produced by and-or released from irradiated axes, and it migrates to the cotyledons (and possibly endosperm) to promote the increase in -galactosidase activity. Gibberellic acid, particularly in the presence of benzyladenine, can replace the requirement for irradiated axes.Abbreviations GA3
gibberellic acid
- R
red light 相似文献
176.
177.
Dr. W. B. Watkins 《Cell and tissue research》1980,207(1):65-80
Summary Antisera raised against ACTH (1–39), -endorphin and the 16K proopiocortin were used, in association with the immunoperoxidase reaction, to localize positively-staining cell bodies and nerve fibres in the hypothalamus of the rat. Antigens, cross-reactive against anti-ACTH (1–39) serum were detected in a fibre system in the rostro-dorsal hypothalamus situated between the optic chiasm and the third ventricle while immunoreactive 16K-like material was present in fibres localized in the caudal hypothalamus, dorso-lateral to the arcuate nucleus. This latter system was also associated with the appearance of ACTH (1–39) and ACTH (17–39) immunoreactivity.Cells of the arcuate nucleus stained positively for ACTH (1–39), 16K antigen and -endorphin, and on examining adjacent thin sections it was observed that cells that contained 16K antigen-like material, also gave a positive immunoreaction with ACTH (1–39) and -endorphin antisera. In the magnocellular system, cells of the supraoptic (SON) and paraventricular (PVN) nuclei also gave a positive immunoreaction with anti-ACTH (1–39), 16K antigen and -endorphin serum. As in the case of the arcuate nucleus, common cells stained for these three antigens.On the basis of the precursor theory for the synthesis of ACTH, 16K antigen and -endorphin, it was not unexpected to find these three fragments of pro-opiocortin localized together in cells of the arcuate nucleus. That ACTH (1–39), 16K antigen and -endorphin-like materials are present in the magnocellular neurosecretory system would suggest that cells of the SON and PVN are not only involved in the synthesis of neurophysin and the neurohypophysial hormones, but also of some products of the pro-opiocortin molecule. Whether the biochemical nature of the ACTH and -endorphin in cells of the SON and PVN is identical to that of anterior pituitary origin remains to be established, as does the biosynthetic relationship between neurophysin and oxytocin/ vasopressin and these fragments of pro-opiocortin.Drs. M.M. Wilkes, S.S.C. Yen, G. Pelletier, B.A. Eipper and R. Walter are thanked for supplying some of the antisera and antigens used in this study. Thanks also go to Ciba-Geigy Ltd. and Organon Inc. for supplies of ACTH (17–39) and ACTH (1–24) respectively. This work was financed by The Medical Research Council of New Zealand 相似文献
178.
Human lymphocyte guanylate cyclase activities are increased in a dose-dependent fashion by incubation of intact cells with phorbol myristate acetate, a tumor promoter and lymphocyte mitogen. Increased activity is detectable after 1 minute, and peak membrane-bound and soluble forms of guanylate cyclase occur after 10- and 30-minute exposure to phorbol myristate acetate, respectively. The soluble form is stimulated much more than the membrane form. Enzyme activities measured in the presence of either Ca2+, Mg2+, or Mn2+ are elevated to similar degrees. Comparisons of phorbol and a series of its diesters revealed a good correlation between the capacities for guanylate cyclase stimulation, lymphocyte mitogenesis, and tumor promotion. 相似文献
179.
The amino reagent 2,4,6-trinitrobenzenesulfonate (TNBS) was found to inactivate mitochondrial F1-ATPase through covalent labeling, which was not reversed by dithiothreitol. The observed rate of inactivation was retarded by inorganic phosphate, but enhanced by prior labeling of F1 with 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-C1). These observations are consistent with the presence of an essential amino group near the bound inorganic phosphate at the catalytic site of F1. A comparison of the observed protection of F1 from NBD-C1 and 5′-p-fluorosulfonyl-benzoyladenosine (FSBA) respectively by inorganic phosphate and by 2′,3′-O-(2,4,6-trinitrophenyl)adenosine 5′-monophosphate (TNP-AMP) suggests that NBD-C1 labels an essential Tyr residue in the positively charged locus for binding the polyphosphate end of ATP, and that FSBA labels an essential Tyr residue in the more hydrophobic locus for binding the adenosine moiety of ATP at the catalytic site of F1. 相似文献
180.
Seiji Suzuki Hiroshi Oka Hiroko Yasuda Masahiro Ikeda Po Yuan Cheng Toshitsugu Oda 《Biochemical and biophysical research communications》1981,99(3):987-993
Isolated rat pancreatic islets, incubated in the presence of extracellular 32Pi to steady state 32P incorporation into cellular phosphopeptides, were exposed to glucose for 10 min. Glucose (16.7 mM) significantly stimulated the phosphorylation of six phosphoproteins with molecular weights of 15,000, 35,000, 49,000, 64,000, 93,000 and 138,000. Mannoheptulose (16.7 mM) markedly inhibited glucose-stimulated phosphorylation of these six phosphoproteins. This protein phosphorylation might be important in mediating glucose-stimulated insulin release. 相似文献