共查询到20条相似文献,搜索用时 15 毫秒
1.
Treatment of 3T3 cell plasma membranes with glycosidase enzymes decreased their ability to inhibit cell growth and also decreased their binding to 3T3 cells. This suggests that carbohydrate is required for complete function of inhibitory activity and that inhibition is associated with membrane adhesion. 相似文献
2.
Y. Yonezawa H. Kondo R. Hirai K. Kaji K. Nishikawa 《Cellular and molecular life sciences : CMLS》1992,48(3):239-245
Sera from different mammalian species displayed great differences in mitogenic activity, as measured by stimulation of DNA synthesis in BALB/c 3T3 cells (3T3 cells). Among the sera examined, fetal bovine serum was least active, and increasing activity was detected in calf serum, human serum, rat serum and mouse serum, in that order. Rat and mouse sera exhibited extremely high mitogenic activity with 3T3 cells, but when TIG-1 human fetal lung fibroblasts were used for the DNA assay instead, the activity levels of all of the sera were lower, and the differences between them were smaller. To determine the reasons for these differences, the heparin-binding growth factors in each serum were separated on a heparin affinity column. Five peaks of DNA-stimulating activity were obtained. Three of these were found in all sera examined, with both 3T3 cells and TIG-1 cells. Two other peaks were found only with 3T3 cells; one was peculiar to rat and mouse sera, with extremely high activity in the rat, and the other was specific to fetal serum. The dependence of the activity of these peaks on the cells used for the test was confirmed using normal rat lung fibroblasts and immortalized rat kidney cells. These findings adequately explain the species-specific differences in mitogenic activity of whole sera, and the variation in activity depending on the cells used for assay of DNA synthesis. 相似文献
3.
Profiling of the secreted proteins during 3T3-L1 adipocyte differentiation leads to the identification of novel adipokines 总被引:3,自引:0,他引:3
Wang P Mariman E Keijer J Bouwman F Noben JP Robben J Renes J 《Cellular and molecular life sciences : CMLS》2004,61(18):2405-2417
Adipose tissue is an endocrine organ capable of secreting a number of adipokines with a role in the regulation of
adipose tissue and whole-body metabolism. We used two-dimensional gel electrophoresis combined with mass spectrometry to
profile the secreted proteins from (pre)adipocytes. The culture medium of 3T3-L1 cells during adipocyte differentiation
was screened, and 41 proteins that responded to blocking of secretion by 20°C treatment and/or brefeldin A treatment
were identified. Prohibitin, stress-70 protein, and adhesion-regulating molecule 1 are reported for the first time as
secreted proteins. In addition, procollagen C-proteinase enhancer protein, galectin-1, cyclophilin A and C, and SF20/IL-25
are newly identified as adipocyte secreted factors. Secretion profiles indicated a dynamic environment including an
actively remodeling extracellular matrix and several factors involved in growth regulation.Received 15 June 2004; received after revision 26 July 2004; accepted 2 August 2004 相似文献
4.
Cytotoxic (CD8+) and helper (CD4+) T cells play a crucial role in resolving infections by intracellular pathogens. The development of technologies to visualize
antigen-specific T cell responses in mice and men over the past decade has allowed a dissection of the formation of adaptive
T cell immunity. This review gives a brief overview of the currently used detection techniques and possible future additions.
Furthermore, we discuss our current understanding of the formation of antigen-specific T cell responses, with particular attention
to the similarities and differences in CD4+ and CD8+ T cell responses, the functional heterogeneity within responder T cell pools and the regulation of CD8+ T cell responses by dendritic cells and CD4+ helper T cells.
Received 16 June 2005; received after revision 2 August 2005; accepted 15 August 2005 相似文献
5.
Major contribution of codominant CD8 and CD4 T cell epitopes to the human cytomegalovirus-specific T cell repertoire 总被引:3,自引:0,他引:3
Nastke MD Herrgen L Walter S Wernet D Rammensee HG Stevanović S 《Cellular and molecular life sciences : CMLS》2005,62(1):77-86
Human cytomegalovirus (HCMV) infection or reactivation is a cause of morbidity and mortality in immunocompromised individuals. In immunocompetent individuals, in contrast, HCMV is successfully controlled by specific CD8 and CD4 T cells. Knowledge of CD8 and CD4 T cell epitopes from HCMV and their immunodominant features is crucial for the generation of epitope-specific T cells for adoptive immunotherapy and for the development of a peptide-based HCMV vaccine. Therefore, we investigated the natural frequencies of a large number of CD8 and CD4 T cell epitopes, including 10 novel ones. We determined several epitopes as immunodominant. Surprisingly, no clear hierarchies were found for CD8 T cell epitopes, indicating codominance. These results will be valuable for adoptive transfer strategies and support initiatives towards development of a peptide-based HCMV vaccine.Received 12 August 2004; received after revision 24 September 2004; accepted 29 October 2004 These authors contributed equally to this work. 相似文献
6.
Summary Electrophysiological experiments demonstrate that triiodothyronine (T3) exerts a direct effect on the membrane of a strain of cultured rat pituitary tumor cells, GH3/B6. These cells respond to pressure application of T3 (2–5 nl, concentration 1·10–10 M) with an increase in the membrane resistance (Rm) and a hyperpolarization. Spontaneously firing cells become silent. 相似文献
7.
E. Cervén 《Cellular and molecular life sciences : CMLS》1990,46(10):993-999
Summary The regulation of cellular growth and proliferation is perhaps the most investigated and elusive problem in cell biology and seems to be possible to solve from almost any angle of study chosen. Among the non-systemic factors that have been discussed are genetic damage, genomic control, regulation by stimulatory and inhibitory peptide factors such as EGF, chalones, and fibronectin, protein kinase activition with tyrosine phosphorylation, adenylylcyclase and cAMP, cGMP, membrane perturbations and specifically in tumours the failure of the Pasteur effect in control of glycolysis, excessive membrane ATPase activity, and excessive hydrolytic and proteolytic activities at the cell surface. This article focusses on the central role of fluxes within the plasma membrane and re-examines the possibility that changes of flux of metabolites, ions, and reducing equivalents may be the common denominator regulating cellular proliferation. 相似文献
8.
In recent years the interest in antimicrobial proteins and peptides and their mode of action has been rapidly increasing due
to their potential to prevent and combat microbial infections in all areas of life. A detailed knowledge about the function
of such proteins is the most important requirement to consider them for future application. Our research in recent years has
been focused on the low molecular weight, cysteine-rich and cationic antifungal protein PAF from Penicillium chrysogenum, which inhibits the growth of opportunistic zoo-pathogens including Aspergillus fumigatus, numerous plant-pathogenic fungi and the model organism Aspergillus nidulans. So far, the experimental results indicate that PAF elicits hyperpolarization of the plasma membrane and the activation of
ion channels, followed by an increase in reactive oxygen species in the cell and the induction of an apoptosis-like phenotype.
Detailed knowledge about the molecular mechanism of action of antifungal proteins such as PAF contributes to the development
of new antimicrobial strategies that are urgently needed.
Received 09 August 2007; received after revision 17 September 2007; accepted 19 September 2007 相似文献
9.
B. Diener N. Beer H. Dürk M. Traiser D. Utesch R. J. Wieser F. Oesch 《Cellular and molecular life sciences : CMLS》1994,50(2):124-126
The gap junctional intercellular communication (GJIC) determined by measuring dye coupling with Lucifer yellow, decreased within 3 d from 66% to 28% in monocultures of rat liver parenchymal cells. Coculturing of the parenchymal cells with a nonparenchymal epithelial cell line from rat liver resulted in increased and stabilized intercellular communication (83% after 3 d). The presence of isolated plasma membrane vesicles of the nonparenchymal epithelial cells also stabilized the intercellular communication between the liver parenchymal cells (70% after 3 d). When liver parenchymal cells were cocultured with a rat liver fibroblast cell line the gap junctional communication between the parenchymal cells was not stabilized (43% after 3 d), and isolated plasma membrane vesicles of the fibroblast were also unable to support the GJIC in parenchymal cells (35% after 3 d). It is concluded that plasma membrane constituents of the nonparenchymal epithelial cells were responsible for the stabilization of the GJIC between parenchymal cells. A heterotypic gap junctional communication between parenchymal and nonparenchymal cells was not observed. 相似文献
10.
Navarro S Aleu J Jiménez M Boix E Cuchillo CM Nogués MV 《Cellular and molecular life sciences : CMLS》2008,65(2):324-337
Human eosinophil cationic protein (ECP)/ ribonuclease 3 (RNase 3) is a protein secreted from the secondary granules of activated
eosinophils. Specific properties of ECP contribute to its cytotoxic activities associated with defense mechanisms. In this
work the ECP cytotoxic activity on eukaryotic cell lines is analyzed. The ECP effects begin with its binding and aggregation
to the cell surface, altering the cell membrane permeability and modifying the cell ionic equilibrium. No internalization
of the protein is observed. These signals induce cell-specific morphological and biochemical changes such as chromatin condensation,
reversion of membrane asymmetry, reactive oxygen species production and activation of caspase-3-like activity and, eventually,
cell death. However, the ribonuclease activity component of ECP is not involved in this process as no RNA degradation is observed.
In summary, the cytotoxic effect of ECP is attained through a mechanism different from that of other cytotoxic RNases and
may be related with the ECP accumulation associated with the inflammatory processes, in which eosinophils are present.
Received 26 October 2007; accepted 23 November 2007 相似文献
11.
H. Bluethmann 《Cellular and molecular life sciences : CMLS》1991,47(9):884-890
Transgenic mice carrying functionally rearranged T cell receptor genes have contributed significantly to our knowledge of T cell development and thymic positive and negative selection processes. In addition, TCR-transgenic mice have been used to investigate mutations affecting thymocyte development, likescid andlpr. Gene targeting by homologous recombination will allow to analyze more specifically the molecular mechanisms underlying thymic selection and peripheral tolerance. 相似文献
12.
Summary Groups of mice were maintained for up to 78 weeks on tryptophan restricted, protein restricted and control diets. Plasma tryptophan levels were significantly reduced by both forms of dietary restriction. Brain serotonin levels were significantly reduced only in mice on the tryptophan restricted diet, but not for mice on the protein restricted diet. The protein-restricted diet contains less of the large neutral amino acids which compete with tryptophan to enter the brain. It is known that protein restriction and tryptophan restriction extend lifespan. The results presented here suggest that extension of lifespan and lowering of brain serotonin are not related. 相似文献
13.
The cytotoxicity of arsenic compounds towards BALB/c 3T3 cells in culture was investigated, together with the role of glutathione (GSH) in the induction of the cytotoxic effects. The rank order of cytotoxicity was as follows: arsenite (As3+)>arsenate (As5+)>dimethylarsinic acid (DMAA)>methylarsonic acid (MAA)>trimethylarsine oxide (TMAO). Arsenobetaine, arsenocholine and the tetramethylarsonium ion were less toxic. Depletion of GSH enhanced the cytotoxic effects of As3+, As5+, MAA and TMAO, while the cytotoxicity of DMAA was markedly reduced by depletion of GSH. These results suggest that GSH plays a role in protecting the cells against the toxic effects of As3+, As5+, MAA and TMAO while it is involved in the induction of the cytotoxic effects of DMAA. 相似文献
14.
Summary Addition of epidermal growth factor to culture medium without calf serum suppressed the increase in cell volume and then enhanced the survival of BSC-1 cells attached to culture dishes. However, these effects of epidermal growth factor were not observed in the case of cells on dishes coated with heat-denatured bovine serum albumin. 相似文献
15.
Summary The inhibitory effects of pargyline and quipazine on chicken growth hormone secretion were overcome by passive immunoneutralization of endogenous somatostatin (SRIF)-14 or SRIF-28(1–14)-like immunoreactivity. Administration of the specific antisera to control birds pretreated with 0.9% NaCl elevated the basal plasma GH concentrations. These results suggest that peptides with SRIF-14 or SRIF-28(1–14)-like immunoreactivity tonically inhibit GH secretion and are at least partially responsible for the inhibitory effects of pargyline and quipazine on GH release in immature domestic fowl. 相似文献
16.
Summary We compared a simple complement-dependent lymphocytotoxicity test with a widely used indirect immunofluorescence procedure to enumerate total T, T helper, and T suppressor lymphocytes in normal blood samples. Results with the two techniques were closely similar. 相似文献
17.
After 24-h fasting, when the recovery of plasma membrane protein isolated from rat liver was unchanged, the enrichment in 5'-nucleotidase was decreased by 16%. Modifications of the lipid composition were also observed and resulted in a 27% decrease of the cholesterol/phospholipid molar ratio. 相似文献
18.
G. Renaud Jacqueline Marais R. Infante 《Cellular and molecular life sciences : CMLS》1980,36(6):642-643
Summary After 24-h fasting, when the recovery of plasma membrane protein isolated from rat liver was unchanged, the enrichment in 5-nucleotidase was decreased by 16%. Modifications of the lipid composition were also observed and resulted in a 27% decrease of the cholesterol/phospholipid molar ratio. 相似文献
19.
Summary The effects of photoperiod, temperature and testosterone treatment on plasma T3 and T4 levels were investigated in the Djungarian hamster. Plasma T3 level was affected by temperature (25°C<7°C) but not by photoperiod. Plasma T4 level was affected by photoperiod (short day < long day) at 25°C. Administration of testosterone increased plasma T4 level under short photoperiod at 25°C. Thus, higher plasma T4 level under long photoperiod at 25°C might be induced by testosterone. 相似文献
20.
Phosphatidylinositol 3-kinase (PI3-kinase) activity has been implicated in regulating cell cycle progression at distinct points
in the cell cycle by preventing cell cycle arrest or apoptosis. In this study, the role of PI3-kinase activity during the
entire G1 phase of the ongoing cell cycle was studied in Chinese hamster ovary (CHO) cells synchronized by mitotic shake-off.
We show that inhibition of PI3-kinase activity during and 2 h after mitosis inhibited cell cycle progression into S phase.
In the presence of the PI3-kinase inhibitor wortmannin or LY294002, cells were arrested during early G1 phase, leading to
the expression of the cleaved caspase-3, a central mediator of apoptosis. These results demonstrate that PI3-kinase activity
is required for progression through the M/G1 phase. In the absence of PI3-kinase activity, cells are induced for apoptosis
in this particular phase of the cell cycle.
Received 7 September 2005; received after revision 26 October 2005; accepted 11 November 2005 相似文献