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31.
A S Edelman B Xue P Sanchez G J Thorbecke 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(3):2206-2212
Dimethylbenz[a]anthracene (DMBA)-induced transplantable fibrosarcomas in B2 homozygous chickens (SC line) grow progressively in normal chickens, but are rejected by chickens immunized previously with irradiated tumor cells and Corynebacterium parvum. Tumor-immune chickens resist challenge by the immunizing tumor lines as well as by some, but not all, fibrosarcoma lines. The pattern of cross-reactivity between four DMBA-induced transplantable tumor lines was examined in detail. Ability to reject a tumor challenge correlated very well (p less than 0.001) with the presence of delayed-type hypersensitivity (DTH) to that tumor. Immunization with one of two of the DMBA-induced lines tested also caused rejection of transplantable tumors developed from methylcholanthrene-induced and benzo(a)pyrene-induced primary fibrosarcomas. Although immunization with tumor caused DTH to chicken embryo fibroblasts (CEF), immunization with CEF failed to cause protective immunity or DTH to tumors. Presence of protective immunity, where tested, also correlated with the ability of spleen cells from immune donors to inhibit tumor growth in Winn tests. Humoral immunity exhibited even greater cross-reactivity than did cellular immunity. Distinct patterns of cross-reactivity were nevertheless observed with respect to the serum antibodies as detected in ELISA. Two of these patterns were also observed in several sera from primary tumor-bearing chickens, both including reactivity with CEF. Such reactivity was absent from normal chicken sera. 相似文献
32.
C S Song J H Yu D H Bai P Y Hester K H Kim 《Journal of immunology (Baltimore, Md. : 1950)》1985,135(5):3354-3359
Simple methods for the generation, purification, and assay of antibodies to the alpha-subunit of insulin receptor from eggs of immunized hens have been described. Chicken antibodies against the alpha-subunit inhibit insulin binding to the receptor and stimulate glucose oxidation as well as autophosphorylation of the beta-subunit. Thus the properties of chicken antibodies are very similar to those of antibodies found in human autoimmune diseases and different from rabbit antibodies obtained against the same antigen. 相似文献
33.
This paper deals with the role of light in the germination of akinetes of Anabaena azollae. The two maxima action spectra are situated at 385 and 615 nm and the stimulation of the germination process by photosynthate was confirmed. The photoreceptor absorbing at 385 nm was identified as a flavin and that at 615 nm as a phytochrome. A model is suggested for the mode of action of light in the germination of akinetes of blue-green algae.C. Tsui 相似文献
34.
Analysis of interspecific quail/chick chimaeras (made by grafting neural primordium from one species to the other) has demonstrated that the neural crest cell population, which gives rises to a large number of derivatives, including the great majority of peripheral ganglion cells, is pluripotential. When peripheral ganglia themselves are transplanted, it can be shown that many of the developmental potentialities of the parent structure are retained, their ultimate expression depending on the microenvironment in which they become located. One of the conclusions obtained from these in vivo studies, that sensory ganglia contain dormant precursors with autonomic potentialities, has been confirmed and extended by the results of in vitro investigations with dissociated 9- to 15-day embryonic quail dorsal root ganglia. Undetectable during normal embryonic development, adrenergic properties (tyrosine hydroxylase immunoreactivity, radio- and cytochemically demonstrable catecholamine production) develop in a population of small, multipolar cells after four days in culture. This differentiation is strongly dependent on the presence of chick embryo extract in the medium. Unlike the postmitotic primary sensory neurons of the ganglia, many of the adrenergic cells were found to incorporate 3H-thymidine during the culture period. These results support the contention that the latent autonomic percursors belong to the non-neuronal compartment of sensory ganglia. 相似文献
35.
The effect of lactation on a number of enzymes involved in transmethylation reactions and the secretion of major methyl compounds into milk have been examined in sheep. The activities of hepatic phospholipid methyltransferase and 5-methyltetrahydrofolate-homocysteine methyltransferase were significantly higher in lactating ewes, compared with those in non-lactating ewes, while the activity of both hepatic and pancreatic glycine methyltransferase was significantly lower in the lactating state. No differences were observed in the activities of hepatic guanidoacetate methyltransferase, betaine-homocysteine methyltransferase and cystathionine beta-synthase on lactation. These results suggest that the extra demand for methyl groups for the secretion of methyl compounds in the milk is facilitated by enhancing the rate of de novo methyl group synthesis and lowering the rate of physiologically nonessential methylation. 相似文献
36.
本文以沙田柚为材料,对其染色体组型及带型进行了观察分析。组型分析:染色体数目2n=18,根据染色体的相对长度分成大小染色体两种类型,前者包括1、2、3、4和5对,后者为6、7、8和9对,根据臂比,9对染色体能够被分成中部着丝点和近中着丝点染色体两种类型。即第5、7,9对为亚中部着丝点,其余为中部着丝点,第6对染色体上有随体;Giemsa带型:除第二对染色体只显中间带外,其余都显着丝点带,并在3、4、8对染色体短臂上和2、3、1对染色体长臂上均显端带,第2、3,6对同源染色体之间的C带显示杂合性。 相似文献
37.
Z G Xue J Smith N M Le Douarin 《Comptes rendus de l'Académie des sciences. Série III, Sciences de la vie》1985,300(13):483-488
From the results of previous studies, we have suggested that "autonomic" cell precursors exist in latent form in sensory ganglia of avian embryos. The potentialities can be expressed when the ganglia are transplanted into a young embryo host. In the present study, we have observed a similar transformation in cultures of dissociated dorsal root ganglia taken from quail embryos of 7-15 days of incubation. From the 4th day of culture onward, numerous adrenergic cells appear. They display tyrosine hydroxylase immunoreactivity, synthesise and store catecholamines and generally differ in size and shape from primary sensory neurons. They and/or their precursors can actively proliferate in culture. The differentiation of these catecholaminergic cells, which can not be detected in quail dorsal root ganglia during normal development in vivo, is dependent on one or more factors present in 9-day chick embryo extract. 相似文献
38.
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40.
植物苯丙氨酸解氨酶(PAL)在细胞分化中的作用 总被引:4,自引:0,他引:4
烟草、丹参和甜叶菊愈伤组织在分化过程中一般都出现两个PAL活性高峰。第一高峰在培养第一、二、三天中出现;第二高峰在第十一天前后出现。前者在分化或不分化培养基中都存在,似与组织分化无关,后者只在分化条件下才有,似可作为组织启动分化的指示酶。分化程度不同的组织,PAL活性有很大差异,即将或刚分化的组织活性最高,随着分化的进程活性趋于降低,老化的组织甚至丧失活性。PAL活性、木质素合成和管状份子形成之间有着紧密的相关性。 相似文献