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21.
M. Yano K. Okuno H. Satoh T. Omura 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(2):183-189
Summary Eight dull mutants that lower the amylose content of rice endosperm as well as waxy mutant and a cultivar with common grains were crossed in a diallele manner. The amylose content of F1 and F2 seeds was determined on the basis of single grain analysis. It was concluded that the low amylose content of dull mutants is under monogenic recessive control. Alleles for low amylose content are located at five loci designated as du-1, du-2, du-3, du-4 and du-5. These loci are independent of wx locus located on chromosome 6. The five du loci have an additive effect in lowering the amylose content. Two loci, du-1 and du-4, were found to be located on chromosomes 7 and 4, respectively. 相似文献
22.
Simone Grinfeld Paul Jacquet Jan Gilles Lucile Baugnet-Mahieu 《Development genes and evolution》1988,197(5):302-304
Summary In some strains of mice, eggs when X irradiated during the pronuclear stage, undergo a mitotic block in the G2 phase of the first cell cycle and cleave when the second division takes place in controls. The importance of this effect varies considerably with the strain and depends exclusively on the maternal genotype. In previous work, two-dimensional electrophoresis showed that eggs blocked at the one-cell stage after irradiation, undergo the same modifications in polypeptide synthesis as two-cell controls of the same age, except at the time of normal first mitosis, where three polypeptide sets of 30, 35 and 45 kDa appear only in cleaving controls. In the present study, we have found phosphorylations in dividing controls, on polypeptides of 30, 35 and 45 kDa. These phosphorylations are not seen in blocked irradiated eggs. 相似文献
23.
Morphological dispersion of introduced Hawaiian finches: evidence for competition and a Narcissus effect 总被引:2,自引:0,他引:2
Summary Morphological analyses were conducted on finch species introduced to Oahu, Hawaii. As many as 25 species of finches representing four families (Emberizidae, Fringillidae, Ploecidae, Estrildidae) have been introduced to Oahu. Of these, 15 species currently have established wild populations. When compared with pools of 25 and 23 species introduced to Oahu, the 15 surviving species are morphologically overdispersed. This result is consistent with the hypothesis that competition has influenced the outcome of these introductions. We also tested the hypothesis that surviving introduced finches in one habitat (sugarcane fields) were morphologically overdispersed. When the seven surviving finch species found in sugarcane were compared with the pools of 25 and 23 species, they too were morphologically overdispersed. However, when the seven sugarcane species were compared with a species pool consisting of only the surviving 15 species found across Oahu, they were not morphologically overdispersed. This result suggests that morphological analyses of community structure based only on comparisons of assemblages of surviving species may be biased by a Narcissus effect. 相似文献
24.
Eiji Kumazawa Akiko Tohgo Tsunehiko Soga Tsuneo Kusama Yasuaki Osada 《Cancer immunology, immunotherapy : CII》1992,35(5):307-314
Summary The antitumor effect of a synthetic lipid A analogue, DT-5461, was investigated using syngeneic tumor models in mice. Intravenous injection of DT-5461 into mice transplanted with solid tumors of MethA fibrosarcoma, MH134 hepatoma, MM46 mammary carcinoma, Lewis lung carcinoma (3LL), and colon adenocarcinomas 26 and 38 resulted in significant reductions in the weight of all tumors except Colon 26, with marked hemorrhagic necrosis of tumor tissues. Efficacy was almost equal to that of anEscherichia coli-type synthetic lipid A (compound 506), and also to those of some chemotherapeutics including Adriamycin, mitomycin C, fluorouracil and cisplatin. Furthermore, DT-5461 was more effective than other immunotherapeutics, including picibanil (OK-432) and lentinan. However, its antitumor effects were inferior to those of Adriamycin or OK-432 against the malignant ascites caused by intraperitoneal inoculation with MethA or with MH134 cells; life span was not prolonged by either intraperitoneal or intravenous administration. In addition, although DT-5461 showed direct inhibitory effects on the in vitro growth of MethA or MH134, these were much weaker than those of Adriamycin. These findings clearly indicated that DT-5461 with systemic administration is a highly effective antitumor agent on solid tumors, and suggest that the antitumor effect of DT-5461 with potent necrotizing activity might derive from indirect mechanisms related to the activation of host immune systems and not to the weak direct cytotoxicity. 相似文献
25.
G Milazzo G L La Rosa R Catalfamo R Vigneri A Belfiore 《Journal of cellular biochemistry》1992,49(3):231-238
The well-known mitogenic effects of TSH observed in vivo on the thyroid are not always reproducible of human thyroid cells in vitro where conflicting results have been obtained. In order to clarify this issue, we have used primary cultures of human thyroid cells obtained from normal tissue and maintained in serum-free medium for several days. In this in vitro model we have studied the effect of TSH on growth by measuring three different parameters: [3H]-thymidine incorporation, cell counts, and DNA measurement. Monolayer cultures were plated at both low and high cell density (2 x 10(4) and 8 x 10(4) cells/25 mm well, respectively). Although at either cell density cultures were equally able to functionally respond to TSH in terms of cAMP accumulation a significant growth response to TSH was observed only in low density cultures. In high density cultures TSH had an antimitogenic effect. Moreover, TSH potentiated the mitogenic effect of insulin only in low density cultures. In contrast to TSH, FCS induced a similar proliferative response at both high and low cell density. Following TSH stimulation, cAMP content was always increased, paralleling the effect of growth in low density but not in high density cultures. The cAMP analogues dibutyryl-cAMP and 8-bromo-cAMP, as well as cholera toxin and forskolin, did not mimic the mitogenic effect of TSH but had an antiproliferative effect. In addition, these agents blunted the proliferative effect of insulin. These data suggest that in thyroid cells TSH is able to elicit both a mitogenic and an antimitogenic effect depending on the environmental conditions such as cell density.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
26.
27.
28.
Noritsugu Yabe Yutaka Matsuya Isao Yamane Mitsuru Takada 《In vitro cellular & developmental biology. Plant》1986,22(7):363-368
Summary A newly developed, serum-free medium (NYSF-404) selects for antibody-producing hybridomas after fusion of antigen-sensitized
mouse spleen cells with myeloma cell lines P3-X63-Ag8-U1 (P3-U1), P3-X63-Ag8-6.5.3 (Ag8.653), or P3-NSI/1-Ag4-1 (NS-1). Without
the need for hypoxanthine-aminopterinthymidine (HAT) selection of hybrid cells, frequency of hybridoma formation in medium
NYSF-404 is higher (twice) than that in serum- and HAT-containing medium. Colonies developed upon limiting dilution in the
presence of the mortal parent myeloma cells in medium NYSF-404 and pure culture of antibody-secreting cells could be subsequently
established. The results suggest that fusions can be done in serum-free medium and that the clonal growth of hybridomas is
dependent on factors produced by parent myeloma cells under serum-free culture conditions. Such factors seem deficient in
serum- and HAT-containing medium or are masked by serum. 相似文献
29.
A relation between gene dosage and UDP-glucose:flavonoid 3-O-glucosyl-transferase (UFGT) activity was found in homozygous dominant and recessive parental lines and their F1 progeny for both of the genes An1 and An2. In both F2 crosses, progeny plants could be classified as belonging to groups showing either a low or a medium to high UFGT activity. Test crosses showed that heterozygous and homozygous dominant plants were present throughout the medium- to high-active group. The dosage relation in F2 plants is most probably confounded by the segregation of modifiers. Thermal inactivation experiments indicated that structurally different UFGT enzymes are formed in homozygous dominant lines as well as in lines homozygous recessive for either An1 or An2. Lines homozygous recessive for the gene An4 contain a UFGT with a half-life time at 55° C of less than 8 min, whereas UFGTs from lines homozygous dominant for An4 show a half-life time of 25 min or above, with one exception. This relation was confirmed in the F2 progeny; heterozygotes for An4 showed an intermediate half-life time. It is concluded that An4 might be the structural gene for the enzyme; An1 and An2 are both regulatory genes. UFGT activity in flowerbuds of An4/An4 plants seems to be lower than in an4/an4 plants. Anthers of flowers of an4/an4 lines, however, are virtually devoid of UFGT activity. 相似文献
30.
A combined single-turnover flash and 35Cl NMR technique has been used to monitor S-state dependence of Cl− binding to PS-II particles derived from mangrove (Avicennia marina). No detectable high-affinity binding was found to particles in the S0 and S1 states, but binding with an affinity comparable to that which activates O2 evolution was found in the S2 and S3 states. 相似文献