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11.
Yan-Hong He Guo-Gui Ning Ya-Lin Sun Yan Hu Xing-Yu Zhao Man-Zhu Bao 《Molecular breeding : new strategies in plant improvement》2010,26(1):19-29
A male sterile line was isolated in marigold (Tagetes erecta L.) and cytological analysis determined this to be a novel genic male sterility trait (Tems). Through the use of amplified fragment length polymorphisms (AFLPs) and bulked segregant analysis (BSA), tightly linked
markers of Tems were identified with a view towards a map-based cloning strategy. It was found that spontaneous homeotic conversion of floral
organs was the underlying cause of the male sterility in this marigold line. Thus, petals of male sterile plants resembled
sepal-like structures and the stamens were partially converted to styles, although without the full characteristics or function
of the true style organs. We have constructed a fine marker-based map for the Tems gene. This is intended to provide a tool for marker assisted selection (MAS) strategies in hybrid breeding and map-based
cloning strategies for the male sterility locus. We discuss the significance of this spontaneously derived genic male sterility
trait relating to the homeotic conversion of floral organs in marigold. 相似文献
12.
Purification and properties of formylglutamate amidohydrolase from Pseudomonas putida. 总被引:4,自引:3,他引:1 下载免费PDF全文
Formylglutamate amidohydrolase (FGase) catalyzes the terminal reaction in the five-step pathway for histidine utilization in Pseudomonas putida. By this action, N-formyl-L-glutamate (FG) is hydrolyzed to produce L-glutamate plus formate. Urocanate, the first product in the pathway, induced all five enzymes, but FG was able to induce FGase alone, although less efficiently than urocanate did. This induction by FG resulted in the formation of an FGase with electrophoretic mobility identical to that of the FGase induced by urocanate. A 9.6-kilobase-pair HindIII DNA fragment containing the P. putida FGase gene was cloned into the corresponding site on plasmid pBEU1 maintained in Escherichia coli. Insertion of the fragment in either orientation on the vector resulted in expression, but a higher level was noted in one direction, suggesting that the FGase gene can be expressed from either of two vector promoters with different efficiencies or from a single vector promoter in addition to a less efficient Pseudomonas promoter. FGase was purified 1,110-fold from the higher-expression clone in a yield of 10% through six steps. Divalent metal ions stimulated activity, and among those tested (Co, Fe, Zn, Ca, Ni, Cd, Mn, and Mg), Co(II) was the best activator, followed by Fe(II). FGase exhibited a Km of 14 mM for FG and a specific activity of 100 mumol/min per mg of protein in the presence of 5 mM substrate and 0.8 mM CoCl2 at 30 degrees C. The enzyme was maximally active in the range of pH 7 to 8. FGase was found to be a monomer of molecular weight 50,000. N-Acetyl-L-glutamate was not a substrate for the enzyme, but both it and N-formyl-L-aspartate were competitive inhibitors of formylglutamate hydrolysis, exhibiting Ki values of 6 and 9 mM, respectively. The absence of FGase activity as an integral part of histidine breakdown in most other organisms and the somewhat uncoordinated regulation of FGase synthesis with that of the other hut enzymes in Pseudomonas suggest that the gene encoding its synthesis may have evolved separately from the remaining hut genes. 相似文献
13.
J Mazurier D Legrand W L Hu J Montreuil G Spik 《European journal of biochemistry》1989,179(2):481-487
In the resting rate, the human peripheral blood lymphocytes did not show detectable surface and intracellular receptors for human lactotransferrin. However, both types of lactotransferrin receptors were expressed during stimulation of lymphocytes with phytohemagglutinin. The appearance of receptors was time-dependent and the number of receptors reached a plateau after at least two days of mitogen stimulation. These results suggest that the presence of surface receptors on mitogen-stimulated lymphocytes is not consecutive to a modification of subcellular distribution but to an induction of biosynthesis of the receptors. As measured by incorporation of [3H]thymidine into DNA, addition of human lactotransferrin in a serum-free medium increased the proliferative activity of phytohemagglutinin-stimulated lymphocytes. Optimal enhancement of [3H]thymidine incorporation was obtained by adding 30% iron-saturated lactotransferrin at a concentration of 0.17 microM. Therefore, the role of lactotransferrin in the response of lymphocytes to mitogen stimulation appears to be similar to that previously described for serotransferrin. The lactotransferrin receptor was visualized using 125I-labeled lactotransferrin on nitrocellulose paper after electroblotting of the Triton X-100 extract of the phytohemagglutinin-stimulated lymphocytes as two protein bands of 100 and 110 kDa molecular mass. Purification of the lactotransferrin receptor from the Triton-X-100-soluble extract of stimulated lymphocytes was performed by antiligand-affinity chromatography. The binding of lactotransferrin to the purified receptors was reversible and dependent on concentration and pH. 相似文献
14.
E Hu K Watkins S Groshen S C Chen B Malloy R Agah P Nichols J Parker A Martin M G Boosalis 《Molecular biotherapy》1990,2(2):96-103
A phase I trial of interleukin-2 and interferon gamma combination treatment in patients with advanced malignancies was performed based on preclinical in vitro and in vivo data which demonstrated synergistic antitumor effect. The toxicities, immune parameters, and tumor responses are described. The clinical and biologic maximal tolerated doses were extrapolated from these data. 相似文献
15.
M Cannon L Hu J Ye D Lawson 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1991,197(4):465-470
The objective of this study was to determine the effects of thyrotropin-releasing hormone (TRH) and bromocriptine on plasma levels of biologically active prolactin in ovariectomized, diethylstilbestrol (DES)-treated rats. Female Long-Evans and Holtzman rats were ovariectomized and each was given a subcutaneous implant of diethylstilbestrol (DES). One week later, groups of DES-treated rats were fitted with indwelling intra-atrial catheters, and 2 days later blood samples were withdrawn before and at 1, 2, 5, 10, and 20 min after intravenous administration of TRH (250, 500, or 1000 ng/rat). Blood samples were obtained from other groups at 4 weeks of DES treatment by orbital sinus puncture under ether anesthesia before and at 30, 60, and 120 min after bromocriptine administration (2.5 mg/rat sc). Plasma was assayed for prolactin by conventional radioimmunoassay (RIA) and by Nb2 lymphoma bioassay (BA). Holtzman rats released significantly more prolactin following TRH than did Long-Evans rats when the RIA was used to measure prolactin. However, when the BA was used to assay prolactin in the same samples, the Long-Evans rats released more prolactin than did the Holtzman rats. In addition, the ratio of the BA to RIA values was significantly increased in both strains following TRH, but the greatest increase was observed in the Long-Evans rats, in which the ratio was 4.5 at the peak of the TRH-induced rise in plasma prolactin. Gel filtration chromatography of plasma obtained at 5 min after TRH treatment in Long-Evans rats revealed large molecular forms of prolactin with BA to RIA ratios of 4-5. In addition, monomeric prolactin had a BA to RIA ratio of 2. Bromocriptine treatment reduced prolactin levels in both strains, but the effect was more rapid in Holtzman than in Long-Evans rats. In addition, bromocriptine treatment of Holtzman, but not Long-Evans, rats significantly reduced the BA to RIA ratio of plasma prolactin. The results indicate that TRH and bromocriptine affect the release of biologically active prolactin to a greater extent than prolactin detected by antibody in the RIA, and that Long-Evans and Holtzman rats respond to these secretagogues differently with regard to BA to RIA comparisons. 相似文献
16.
M Cannon L Hu J Ye D Lawson 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1991,197(4):471-476
This study was conducted to determine the plasma levels of prolactin in prepubertal and young, postpubertal, proestrus rats of mammary tumor-susceptible (Sprague-Dawley) and tumor-resistant (Long-Evans) strains using a sensitive bioassay-Nb2 lymphoma cell replication. Prepubertal Long-Evans rats had significantly higher levels of prolactin than did Holtzman Sprague-Dawley rats of the same age. Likewise, Long-Evans rats secreted significantly more prolactin into the blood on the afternoon and evening of proestrus than did Holtzman rats. Finally, ovariectomized Long-Evans rats released more prolactin into the blood at 1 day, but not at 8 or 15 days, of treatment with diethylstilbestrol. Prolactin levels determined by conventional radioimmunoassay and by bioassay were similar except on the afternoon of proestrus, when, in both strains of rats, the bioassay to radioimmunoassay ratio increased significantly above 1.0 during the late evening. In addition, the ratio was significantly less than 1.0 in the early and late afternoon in the Holtzman rats, but not Long-Evans rats. These data indicate that a strain of rats that is resistant to experimentally induced mammary cancer has higher prolactin levels in the blood than does a strain that is susceptible to mammary cancer at a time when mammary gland growth is rapid. Furthermore, there are times during the proestrus prolactin surge when the bioassay yielded higher and lower values of prolactin than radioimmunoassay of the same samples, suggesting functional heterogeneity of prolactin that may impact on mammary gland or other target tissue function. 相似文献
17.
W L Hu C E Goldring N R Rao C Rice-Evans R H Burdon A T Diplock 《BioFactors (Oxford, England)》1992,4(1):47-49
Studies on glutathione (GSH) metabolism in an established baby hamster kidney fibroblast cell line (BHK-21/C13) and in its polyoma virus-transformed counterpart (BHK-21/PyY) have revealed a significant stimulation of intracellular GSH peroxidase (GSHpx) activity (selenium-independent plus selenium-dependent) by alpha-tocopherol supplementation (14 microM). This stimulation was found to be much greater in the transformed cells. Other GSH-requiring enzyme activities (i.e. GSH reductase and GSH S-transferase) were unaltered by alpha-tocopherol treatment, suggesting a degree of specificity in its action on GSHpx. In unsupplemented growth media, the GSHpx activity in both cell lines was significantly decreased by oxidative stress. However, the same stress applied to the alpha-tocopherol-supplemented cells had no effect on the stimulated GSHpx activity, suggesting that some protection was afforded by the alpha-tocopherol. 相似文献
18.
神农架金丝猴的生态学观察 总被引:3,自引:0,他引:3
金丝猴(Rhinopithecus roxellanae)仅产于我国,属国家Ⅰ级保护动物,自然分布于四川、陕西、甘肃的部分地区和湖北省神农架自然保护区。1983年以来,笔者对神农架金丝猴生存环境生态习性等作了长期观察研究,结果报道如下。 相似文献
19.
20.
本文研究了中国广东汉族健康人群apoAI-CⅢ-AIV基因簇DNA限制性内切酶PstI、SstI和EcoRI片段长度多态性。其中等位基因P_1,P_2,S_1,S_2,R_1和R_2的频率分别为0.98,0.02,0.96,0.04,0.90和0.10。经卡方检验符合Hardy-Weinbery氏遗传平衡,与其他种族比较,本文结果显示中国广东汉族人P_2等位基因频率低于日本人、亚洲印第安人和高加索人,S_2等位基因频率低于日本人、菲律宾人、沙特阿拉伯人和亚洲印第安人,而与高加索人相近,R_2等位基因频率稍高于高加索人。不同种族间apoAI-CⅢ-AIV基因簇DNA多态频率无疑存在差异,这种差异可能是由于遗传漂变和自然选择单独或联合作用所致。对P_1、P_2,S_1、S_2和R_1、R_2构成的单倍型和连锁平衡程度进行了分析,结果显示这些单倍型处于连锁不平衡状态。 相似文献