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 31 毫秒
1.
Summary The temperate race (D) ofS. peregrina undergoes pupal diapause in response to certain environmental conditions of photoperiod (13L:11D–11L:13D) and temperature (under 20°C). The tropical race (ND) does not do so under the same circumstances. The tendency toward diapause was suppressed in 30–40% of the hybrids of crossings D×ND and ND×D even under such short day and low temperature conditions as 11L:13D–9L:15D, 20°C. For entering diapause, the hybrids require a shorter day length (13L:11D) than that of (D) parents (15L:9D).We thank Dr R. Kano and Dr S. Shinonaga, Tokyo Medical and Dental University, for supplying the New Guinean material.  相似文献   

2.
Summary Decreased activities of both the inhibitory modulator of adenosine 35-monophosphate (cAMP)-dependent protein kinase (A-PK) as well as the stimulatory modulator of guanosine 35-monophosphate (cGMP)-dependent protein kinase (G-PK) from the mouse cerebellum were noted due to the administration of excessive doses of ethanol, caffeine, and phenobarbital for up to 28 days. The dose-dependence of the inhibition of A-PK or the stimulation of G-PK was observed as a function of the amount of protein kinase modulators in the cerebellum of mice receiving different doses of ethanol.Acknowledgments. This work was supported by a grant (RR 08119-06-PK modulator project) from NIH, USA. J.L. Williams, T. Floyd-Jones, C.F. Duggans, D.L. Boone, and S.O. Smith were prebaccalaureate trainees of MBS program. Authors thank Dr J.F. Kuo of Emory University for encouragement in this project.  相似文献   

3.
Summary Daily administration for 3 days of cortisone (25 g/g b.wt), thyroxine (1 g/g b.wt) or insulin (12.5 mU/g b.wt) to 8-day-old suckling mice does not induce a premature decrease of the phosphohydrolase activity of intestinal glucose-6-phosphatase.Supported by grant MA-5969 from the Medical Research Council of Canada (D.M.). C.M. is a recipient of a studentship from MRC of Canada. D.M. is a chercheur-boursier du Conseil de la recherche en santé du Québec.  相似文献   

4.
Summary The levels of melatonin in plasma were measured at hourly intervals for 24 h in 8 sheep, 4 under 8L:16D (short day) and 4 under 7L:10D:1L:6D (skeleton long day) after 38 days of exposure. Mean concentrations did not differ significantly between treatments (52 pg/ml under short days; 91 pg/ml for skeleton long days), but the levels were more stable during 24 h in the SD treatment. Under skeleton long days there were 3 peaks during the 10D scotophase, with low levels during the 6D scotophase and the 7L photophase.  相似文献   

5.
Chinese Cabbage (Brassica sinensis L. var. Cantonner) protoplasts were infected by Turnip yellow mosaic virus (TYMV) and inoculated in the presence or absence of actinomycin D. Virus production was determined 40 hrs. after inoculation, the time required for the virus replication cycle to be terminated. While actinomycin D had no effect on TYMV production when present at a concentration of 1 microng/ml, a 50 to 80% inhibition of virus production was noticed at concentrations of the order of 5 to 10 microng/ml, and the inhibition reached 90% with 25 microng/ml.  相似文献   

6.
Our previous study revealed that passive cutaneous anaphylaxis (PCA) can be produced in congenitally mast cell-deficient WBB6F1-W/Wv (abbreviated as W/Wv) mice on sensitization with undiluted or slightly diluted allogeneic and xenogeneic antisera but not on sensitization with allogeneic monoclonal immunoglobulin (Ig)E and IgG1 antibodies regardless of the antibody concentration [1]. In view of these findings, the present study was conducted to characterize PCA in this strain from its drug susceptibilities using mast cell-bearing WBB6F1-+/+ (abbreviated as +/+) and B6D2F1 mice as references. PCA in W/Wv mice mediated by a low dilution (1  4) of hyperimmune serum to bovine serum albumin of the B6D2F1 mouse origin was markedly suppressed by CV-6209, an antagonist of platelet-activating factor (PAF), but not by antihistamines such as cyproheptadine and oxatomide. In contrast, PCA in +/+ and B6D2F1 mice mediated by a high dilution (1  128) of the anti-serum (virtually by IgG1 antibody) was nearly completely suppressed by antihistamines but not by CV-6209. A remarkable difference between PCA in W/Wv and reference mice was also observed in the susceptibility to monoclonal anti mouse granulocyte (Gr-1) antibody PCA in W/Wv mice was potently suppressed by the 1- to 3-day pretreatment with this antibody but that in references was not at all. Putting these present results together with the previous finding that anti-granulocyte antibody greatly reduces circulatory Gr-1+ leukocytes, 1 to 3 days after the treatment [2], it is highly probable that PCA in W/Wv mice mediated by some antibody isotypes other than IgE and IgG1 is produced by PAF mainly released from Gr-1+ cells, while IgG1 antibody-mediated PCA in mast cell-bearing reference mice is evoked by histamine derived from mast cells. PCA homologous to that in W/Wv mice could also be produced in the reference mice on sensitization with undiluted or slightly diluted antiserum, when generalized blueing due to excess IgG1 antibody was removed by the oxatomide treatment be fore the antigen challenge. Received 10 December 1997; received after revision 2 February 1998; accepted 23 February 1998  相似文献   

7.
Viable metacyclic forms of T. cruzi, Y strain, treated with an adequate dose of actinomycin D (50 micrograms Act-D/ml/10(7) parasites/ml for 72 h at 28 degrees C) showed the following properties: 1) they lost their ability to replicate in culture medium, in blood and in tissues of normal mice and were no longer able to incorporate tritiated thymidine; 2) they could not penetrate into Vero cells and could not replicate inside normal macrophages; 3) they retained their immunogenicity and the ability to protect mice against a virulent infection; 4) they did not induce histological lesions as described in chronic experimental Chagas' disease.  相似文献   

8.
The antiviral activity of Shigyaku-to (TJS-109), a traditional Chinese herbal medicine, was investigated in mice infected with herpes simplex virus type 1 (HSV-1). TJS-109 is a combination of the medicinal plant extracts fromZingiberis siccatum rhizoma,Aconiti tuber andGlycyrrhizae radix in a specific proportion. Mice infected with a 10 LD50 dose of HSV-1 were treated with TJS-109 orally at doses of 1.25 to 20 mg/kg 2 days before, and 1 and 4 days after the infection. The treated groups had 80% (1.25 mg/kg), 40% (5 mg/kg) and 23% (20 mg/kg) mortality rates 25 days after the infection as compared with a 100% mortality rate in control mice treated with saline. When HSV-1 infected mice (recipients) received CD8+T cell fractions derived from spleens of mice treated with TJS-109 (donors), 70% of recipients survived, as compared with 0% survivors in the groups of mice treated with saline, B cell fractions, CD4+ T cell fractions or macrophage-enriched fractions prepared from the same donors. TJS-109 did not show any virucidal activities against HSV-1 or any virostatic activities on the growth of HSV-1 in Vero cells. These results suggest that TJS-109 protected mice exposed to lethal amounts of HSV-1 through the activation of CD8+ T cells.  相似文献   

9.
Summary Viable metacyclic forms ofT. cruzi, Y strain, treated with an adequate dose of actinomycin D (50 g Act-D/ml/107 parasites/ml for 72 h at 28° C) showed the following properties: 1) they lost their ability to replicate in culture medium, in blood and in tissues of normal mice and were no longer able to incorporate tritiated thymidine; 2) they could no penetrate into Vero cells and could not replicate inside normal macrophages; 3) they retained their immunogenicity and the ability to protect mice against a virulent infection; 4) they did not induce histological lesions as described in chronic experimental Chagas' disease.  相似文献   

10.
Summary The influence of somatostatin on tumor cell growth was studied in vivo in mice (sarcoma 180 ascites tumor and Lewis lung tumor) and in vitro on nontransformed and polyoma-transformed cell lines. 4 or 20 g/100 g of cyclic somatostatin and 4 g/100 g of linear protamin Zn-bound somatostatin were injected s.c. twice daily in the in vivo study. Cyclic somatostatin (1, 4 or 10 g/ml) was added twice daily to the cell cultures. Somatostatin administration influenced neither the survival of animals nor the growth rate of cultured cell lines. *** DIRECT SUPPORT *** A2025117 00011  相似文献   

11.
Summary 9 groups of 6 female rats were used in an experiment using fraction 3 ofTrypanosoma rhodesiense. 500 g gave 100% immunoprotection and 1000 and 1500 g gave 66% immunoprotection when challenged with 5×102 T. brucei. 2 groups of 10 female rats were tested for a short period inoculation immune response. In this, 750 g of fraction 3 ofT. rhodesiense gave 70% immunoprotection when challenged withT. brucei.I thank the University of Zambia for support; Dr M. A. Q. Awan, Mazabuka, Zambia, forT. rhodesiense andT. brucei; Prof. J. W. Kibukamusoke, Dr O. Okong'o and Dr W. W. Anokbonggo for advice; Mr L. Nyaliti for technical help.  相似文献   

12.
Summary Using the Fell technique of organ culture of cartilage in a chemically defined medium, it has been shown that prostaglandin A1 at a concentration of 25 g/ml caused chondrocyte death in chick embryonic limb rudiments. An equimolar concentration of PGE2 was not toxic to the cells.Acknowledgments. We are grateful for the support of C. J. K. by the Medical Research Council and of D. L. G. by the Arthritis and Rheumatism Council for Research. Our thanks are due to Dame Honor Fell, F. R. S. for invaluable advice and guidance, to Dr J. Pike (Upjohn Co.) for supplies of prostaglandin A1, and to Dr Sylvia Fitton-Jackson for the gift of culture medium.  相似文献   

13.
Summary The denucleation of L cells and human lymphocytes in suspension was carried out by incubation with cytochalasin D25 and 50 g/ml and with ultracentrifugation over a discontinuous Ficoll gradient. Ultrastructural examination of the separate layers confirmed the presence of the anucleate cytoplasm (cytoplasts) with intact membrane and the separated nuclei (karyoplasts).This work was supported by a grant from the National Cancer Institute of Canada.  相似文献   

14.
Summary Yellow phenocopies ofDrosophila melanogaster were produced by raising larvae on -DMT contaminated media. Using a survivorship test, the sensitive period for phenocopy induction was found to occur during the third larval instar of development, with increased survivorship at 1% -DMT compared with lower concentrations. It was also found that treatment with -DMT significantly slowed development. These findings are related to the relevant morphological and behavioral developmental pathways and to phenocopy induction.Publication No. 35 from the Evolutionary Genetics Laboratory, University of Auckland.Acknowledgments. We thank the New Zealand Entomology Society for a grant from their Anniversary Fund to R. D. Newcomb and the University Grants Committee, Research Grant No. 394.597 to D.M. Lambert.  相似文献   

15.
Summary Ecdysterone has been identified in the schistosomiasis vectorBiomphalaria glabrata Say and inHelix aspersa Müller as well as inLymmaea stagnalis L. by chromatography, bioassay, radioimmunoassay, derivatization and by mass spectroscopy. Analysis of the food, faeces and hepatopancreas suggest that the sterol is derived from the diet. The probable function of ecdysterone in relation to calcification of the shell is discussed in this paper.We wish to thank Professor P. Karlson and Dr J. Koolman (Phillips University, Marburg-Lahn, FRG) for providing facilities for RIA. The initial study was begun at the University of Sussex and continued at the Courtauld Institute of Biochemistry, Middlesex Hospital Medical School, London, while D.L.W. was supported by the Ministry of Overseas Development. London and the Medical Research Council of Great Britain (grant G974/525/T). We thank Mr P. Mellon for the mass spectrum and Dr G.B. Russell for his interest in the earlier part of this study. We also thank Professor E. Scherer and Dr Q. Uwe (University of Essen, FRG) for their help in the irradiation ofL. stagnalis.Gauss Str. 82, D-4630 Bochum 5 (Federal Republic of Germany). Research results usingL. stagnalis were submitted for the Philips Europa Wettbewerb für junge Forscher und Erfinder (1979) in a thesis entitled Zur Frage der Existenz von Steroiden und Gonadoliberin bei der Grossen Schlammschnecke (Lymmaea stagnalis L.): ein Beitrag zur Evolution der Insekten- und Wirbeltierhormone.  相似文献   

16.
Summary Treating VY/WfL-A vy /a mice with 5-androstan-17-one, a mammalian glucose-6-phosphate dehydrogenase inhibitor, prevented the mice from becoming obese. The weight difference between treated and controlA vy /a mice was mainly due to a decreased accumulation of triacylglycerol. The compound did not suppress appetite, had no detectable toxicity and did not affect the lipogenesis rates in the liver and carcass. The weight-controlling effect of 5-androstan-17-one inA vy /a mice was reversible upon withdrawal of treatment.The authors wish to thank Mr W.R. Gibson and Drs C.G. Culbertson and P.N. Harris for performing the pathological examinations.  相似文献   

17.
Zusammenfassung Die Injektion von N6-2-O-Dibutyryl-adenosin-3 5-monophosphat in den lateralen Hirnventrikel von Kaninchen führt zu einer langanhaltenden Fieberreaktion, was vermuten lässt, dass zyklisches Adenosin-35-monophosphat als weiterer Mediator in der Genese des Fiebers fungiert.  相似文献   

18.
Summary The binding of coumarin to serum proteins of the rat has been demonstrated. Of the total bound coumarin (37% of injected dose), 36% was bound to the slow and fast 1 globulins, 11% to the post albumins, 10% to globulin and 9% to albumin.  相似文献   

19.
Urinary excretion of glycated albumin was quantitated in genetically hyperglycemic mice (C57BL-Ks-J, db/db mice), a model for non-insulin-dependent diabetes mellitus, and compared with their non-diabetic littermates. The data indicated a preferential excretion of glycated albumin in non-diabetic mice. This phenomenon of editing of glycated albumin is decreased significantly in diabetic mice. Quantitative measurements of overall excretion of glycated albumin suggested that the loss of editing in diabetic mice is due to the dilution of glycated albumin by the unmodified albumin which is excreted in large amounts in diabetic mice. Therefore, the loss of editing observed in this model resembled the one we characterized in insulin-dependent diabetic humans and a streptozotocin-diabetic rat model3.  相似文献   

20.
    
Zusammenfassung Es wurde Actinomycin D s.c. an junge Ratten verabreicht. Beobachtet wurde die Wirkung der Substanz auf Körpergewicht, Uterusgewicht sowie auf die alkalische Phosphataseaktivität des Uterus vor und nach 17-Oestradiol Stimulation. Actinomycin D (10µg/40 g/Ratte) verhinderte sowohl bei mit Oestradiol behandelten Tieren, wie auch bei den Kontrollen ein Ansteigen des Körper- oder Uterusgewichts. Der Einfluss auf die durch Oestradiol induzierte alkalische Phosphataseaktivität des Uterus blieb minimal und bedeutungslos.  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