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101.
102.
Cultures of dissociated brain cells from 15-day-old fetal mice were grown in the presence and absence of 20 or 50 nM triiodothyronine (T3), 30 or 300 nM cortisol, and 30 nM cortisol plus 50 nM T3 added to chemically defined media or in media supplemented with 15% serum from control and hypothyroid calves. The specific activities of five lysosomal enzymes--N-acetyl galactosaminidase, beta-glucuronidase, beta-galactosidase, cathepsin B, and dipeptidyl aminopeptidase I (DAP-I)--were higher in cells grown in calf serum than in cells grown in defined media. Of these enzymes, only DAP-I was elevated in activity when the cells were grown in hypothyroid calf serum instead of control calf serum. Elevation of DAP-I activity was reversed by addition of 20 nM T3 to hypothyroid calf serum. The enzymatic properties of DAP-I were similar whether the cells were grown in control or hypothyroid calf serum and were similar to those reported for human fibroblasts and the purified enzyme. When the cells were grown in defined media, cortisol decreased the activities of all lysosomal enzymes, with 300 nM cortisol being more effective than 30 nM cortisol. Addition of 50 nM T3 to 30 nM cortisol decreased DAP-I activity more than 30 nM cortisol alone, but 50 nM T3 alone in defined media did not alter DAP-I levels. The reduction of DAP-I activity in these cells by T3 required cortisol, unidentified components in serum, or both.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
103.
Magdalena Torres M. France Bader Dominique Aunis M. Teresa Miras-Portugal 《Journal of neurochemistry》1987,48(1):233-235
Chromaffin cells both recently isolated or in culture present a high-affinity adenosine transporter with a Km value of 1 microM. When cells were exposed to nerve growth factor (NGF; 10 ng/ml), the adenosine transporter affinity decreased to 3 microM. This value was maintained from 3 days after plating to the end of the culture period. A change in the transport capacity was observed, with a significant increase (approximately 200-260%) in NGF-cultured cells throughout the period studied. 相似文献
104.
S-100 Protein in Clonal Astroglioma Cells Is Released by Adrenocorticotropic Hormone and Corticotropin-Like Intermediate-Lobe Peptide 总被引:4,自引:1,他引:3
Fujiko Suzuki Kanefusa Kato Taiji Kato Nobuaki Ogasawara 《Journal of neurochemistry》1987,49(5):1557-1563
S-100 protein in clonal GA-1 and C6 rat glioma cell lines was released in serum-free medium supplemented with adrenocorticotropic hormone (ACTH). The induction of S-100 protein release by ACTH was dose-dependent, showing a half-maximal release at about 5 microM, and the S-100 protein concentration in the medium increased sharply within 3 min, but slightly during further incubation. The S-100 protein release was apparently accompanied by a decrease in the membrane-bound form of S-100 protein in the cell. The S-100 protein release was induced not by the ACTH1-24 fragment, which exhibits the known effects of ACTH, but by the ACTH18-39 fragment, which is designated as corticotropin-like intermediate-lobe peptide (CLIP). These results indicate that the C-terminal half of ACTH is responsible for the S-100 protein release. The enhancement of S-100 protein release by ACTH was also observed in normal rat glioblasts. The release induced by ACTH was apparently specific to S-100 protein, because little release of the cytoplasmic enzymes, creatine kinase, and enolase was observed under the same conditions. High concentrations (5 mM) of dibutyryl cyclic AMP or dibutyryl cyclic GMP were also found to induce S-100 protein release; however, catecholamines (epinephrine, norepinephrine, isoproterenol, and dopamine), acetylcholine, and glutamic acid did not enhance the release.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
105.
感染环形泰勒焦虫(Theileria annulata)的牛外周血白细胞的形态观察 总被引:1,自引:1,他引:0
用光镜及扫描电镜观察了体外高代培养的含牛焦虫颗粒的牛外周血白细胞的形态及在细胞周期中细胞表面的特征性变化。这种经多年传代的含虫的牛外周血白细胞恢复了分裂和繁殖的能力,目前已成为较稳定的细胞系。细胞表面具多种伪足突起,如叶状、丝状及绒毛状。细胞周期中备期细胞表面的主要特征是:S期:细胞平扁,边缘具薄的时状伪足及丝状伪足;G_2期:细胞中部隆起,表面具少量绒毛状伪足;G_1期:绒毛状结构少或无,而出现丝状及小的叶状伪足,细胞仍保持球形;M期:细胞球形,表面密被以绒毛。作者根据扫描电镜的观察认为光镜下所观察的两类细胞,实际上是反映了一种细胞处于不同发育阶段时的特征。 相似文献
106.
107.
Mutations in the E1a gene of type 5 adenovirus result in oncogenic transformation of Fischer rat embryo cells 总被引:1,自引:0,他引:1
G J Duigou L E Babiss W S Liaw S G Zimmer H S Ginsberg P B Fisher 《Journal of cellular biochemistry》1987,33(2):117-126
Transformation of a specific clone of Fischer rat embryo (CREF) cells with wild-type 5 adenovirus (Ad5) or the E1a plus E1b transforming gene regions of Ad5 results in epithelioid transformants that grow efficiently in agar but that do not induce tumors when inoculated into nude mice or syngeneic Fischer rats. In contrast, CREF cells transformed by a host-range Ad5 mutant, H5hrl, which contains a single base-pair deletion of nucleotide 1055 in E1a resulting in a 28-kd protein (calculated) in place of the wild-type 51-kd acidic protein, display a cold-sensitive transformation phenotype and an incomplete fibroblastic morphology but surprisingly do induce tumors in nude mice and syngeneic rats. Tumors develop in both types of animals following injection of CREF cells transformed by other cold-sensitive Ad5 E1a mutants (H5dl101 and H5in106), which contain alterations in their 13S mRNA and consequently truncated 289AA proteins. CREF cells transformed with only the E1a gene (0-4.5 m.u.) from H5hrl or H5dl101 also produce tumors in these animals. To directly determine the role of the 13S E1a encoded 289AA protein and the 12S E1a encoded 243AA protein in initiating an oncogenic phenotype in adenovirus-transformed CREF cells, we generated transformed cell lines following infection with the Ad2 mutant pm975, which synthesizes the 289AA E1a protein but not the 243AA protein, and the Ad5 mutant H5dl520 and the Ad2 mutant H2dl1500, which do not produce the 289AA E1a protein but synthesize the normal 243AA E1a protein. All three types of mutant adenovirus-transformed CREF cells induced tumors in nude mice and syngeneic rats. Tumor formation by these mutant adenovirus-transformed CREF cells was not associated with changes in the arrangement of integrated adenovirus DNA or in the expression of adenovirus early genes. These results indicate, therefore, that oncogenic transformation of CREF cells can occur in the presence of a wild-type 13S E1a protein or a wild-type 12S E1a protein when either protein is present alone, but does not occur when both wild-type E1a proteins are present. 相似文献
108.
Summary We have identified a cDNA coding for the murine keratin D from a collection of clones representing F9 teratocarcinoma stem cell mRNA sequences. These sequences are synthesized specifically after the addition of retinoic acid and cAMP to the culture medium. The clone is 1,382 nucleotides long and contains the entire information for the active polypeptide, the complete 3 end and most, if not all, of the 5 non-coding region. The mRNA is found in hepatocytes, in PYS-2 cells (an endodermal cell line) and in differentiated (retinoic-acid-treated) F9 cells, but not in untreated F9 cells. The length of the mRNA is 1.4 kb, as estimated by Northern blot hybridization. Southern hybridization performed under very stringent conditions detects a single fragment hybridizing strongly with the cloned cDNA, suggesting that the mouse genome contains only one or very few copies of this gene. We present the first complete sequence of a keratin expressed in simple epithelia, i.e. keratin D, and discuss its structural features. 相似文献
109.
Dinucleoside tetraphosphate variations in cultured tumor cells during their cell cycle and growth 总被引:3,自引:0,他引:3
Gilbert Moris Denise Meyer Georges Orfanoudakis Nicole Befort Jean-Pierre Ebel Pierre Remy 《Biochimie》1987,69(11-12):1217-1225
Asynchronous and synchronized cultures of A549 and HTC cells were used to detect possible, cell cycle or cell density specific variations in the intracellular pools of dinucleoside tetraphosphates (Ap4X). No important variations of the nucleotide pools were observed during cell growth. When HTC cells were released from mitotic arrest, a decrease by a factor of N3 Ap4X and ATP levels was observed when the cells entered the G1 phase. This decrease is essentially due to cell doubling. When A549 cells were released from an arrest at the G1/S boundary, the nucleotide pool size increased slightly during the G2 phase just before mitosis. This result is in agreement with both earlier data from our laboratory and the observed decrease in Ap4X pool after release from mitotic-arrested HTC cells. These results suggest that the Ap4X and ATP pools are only subjected to very small variations during the cell cycle, essentially in the G2 phase and after mitosis. 相似文献
110.
Summary An analysis of the allometric relations of the total volumes occupied by prolactin (PRL) and corticotropic (ACTH) cells (PRL volume and ACTH volume, respectively) to body length and a study of the immunocytochemical staining intensity of PRL and ACTH cells were used to determine the differences in activity of PRL and ACTH cells in freshwater-reared and in saltwater-reared Cynolebias whitei during the entire lifespan of this annual cyprinodont fish. An inflection in the allometric relation of PRL volume to body length was observed in fish of one-week old. The relatively large PRL volume in younger fish may be related to PRL cell activity before hatching. No inflections were observed in the allometric relations of PRL volume and ACTH volume to body length at the onset of maturation and the onset of ageing, indicating that the increased pituitary growth in maturing and ageing C. whitei is not the result of changes in PRL or ACTH cells. The slope of the allometric relation of PRL volume to body length in freshwater-reared fish was significantly steeper than the slope in saltwater-reared fish. The PRL volume in adult freshwater-reared fish was eight times larger than that in saltwater-reared fish of the same length. The intensity of immunocytochemical staining of saltwater PRL cells was significantly reduced. These volumetric and staining differences correspond to the low functional demand put upon PRL cells in saltwater-adapted fish. In contrast, the slope of the allometric relation of ACTH volume to body length and the intensity of immunocytochemical staining of ACTH cells were similar in freshwater-reared and in saltwater-reared fish. It is concluded that the functional demand put upon ACTH cells is similar in freshwater-reared and saltwater-reared C. whitei; the involvement of ACTH cells in the osmoregulation of the fish in both environments is similar. 相似文献