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Differential response of cycling and noncycling cells to inducers of DNA synthesis and mitosis 总被引:1,自引:0,他引:1 下载免费PDF全文
The objective of this study was to determine whether cells in G(0) phase are functionally distinct from those in G(1) with regard to their ability to respond to the inducers of DNA synthesis and to retard the cell cycle traverse of the G(2) component after fusion. Synchronized populations of HeLa cells in G(1) and human diploid fibroblasts in G(1) and G(0) phases were separately fused using UV-inactivated Sendai virus with HeLa cells prelabeled with [(3)H]ThdR and synchronized in S or G(2) phases. The kinetics of initiation of DNA synthesis in the nuclei of G(0) and G(1) cells residing in G(0)/S and G(1)/S dikaryons, respectively, were studied as a function of time after fusion. In the G(0)/G(2) and G(1)/G(2) fusions, the rate of entry into mitosis of the heterophasic binucleate cells was monitored in the presence of Colcemid. The effects of protein synthesis inhibition in the G(1) cells, and the UV irradiation of G(0) cells before fusion, on the rate of entry of the G(2) component into mitosis were also studied. The results of this study indicate that DNA synthesis can be induced in G(0)nuclei after fusion between G(0)- and S-phase cells, but G(0) nuclei are much slower than G(1) nuclei in responding to the inducers of DNA synthesis because the chromatin of G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells is more condensed than it is in G(1) cells. A more interesting observation resulting from this study is that G(0) cells differ from G(1) cells with regard to their effects on the cell cycle progression of the G(2) nucleus into mitosis. This difference between G(0) and G(1) cells appears to depend on certain factors, probably nonhistone proteins, present in G(1) cells but absent in G(0) cells. These factors can be induced in G(0) cells by UV irradiation and inhibited in G(1) cells by cycloheximide treatment. 相似文献
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Danilo ML Prado Fabiana B Benatti Ana L de Sá-Pinto Ana P Hayashi Bruno Gualano Rosa MR Pereira Adriana ME Sallum Eloisa Bonfá Clovis A Silva Hamilton Roschel 《Arthritis research & therapy》2013,15(2):R46
Introduction
Exercise training has emerged as a promising therapeutic strategy to counteract physical dysfunction in adult systemic lupus erythematosus. However, no longitudinal studies have evaluated the effects of an exercise training program in childhood-onset systemic lupus erythematosus (C-SLE) patients. The objective was to evaluate the safety and the efficacy of a supervised aerobic training program in improving the cardiorespiratory capacity in C-SLE patients.Methods
Nineteen physically inactive C-SLE patients were randomly assigned into two groups: trained (TR, n = 10, supervised moderate-intensity aerobic exercise program) and non-trained (NT, n = 9). Gender-, body mass index (BMI)- and age-matched healthy children were recruited as controls (C, n = 10) for baseline (PRE) measurements only. C-SLE patients were assessed at PRE and after 12 weeks of training (POST). Main measurements included exercise tolerance and cardiorespiratory measurements in response to a maximal exercise (that is, peak VO2, chronotropic reserve (CR), and the heart rate recovery (ΔHRR) (that is, the difference between HR at peak exercise and at both the first (ΔHRR1) and second (ΔHRR2) minutes of recovery after exercise).Results
The C-SLE NT patients did not present changes in any of the cardiorespiratory parameters at POST (P > 0.05). In contrast, the exercise training program was effective in promoting significant increases in time-to-exhaustion (P = 0.01; ES = 1.07), peak speed (P = 0.01; ES = 1.08), peak VO2 (P = 0.04; ES = 0.86), CR (P = 0.06; ES = 0.83), and in ΔHRR1 and ΔHRR2 (P = 0.003; ES = 1.29 and P = 0.0008; ES = 1.36, respectively) in the C-SLE TR when compared with the NT group. Moreover, cardiorespiratory parameters were comparable between C-SLE TR patients and C subjects after the exercise training intervention, as evidenced by the ANOVA analysis (P > 0.05, TR vs. C). SLEDAI-2K scores remained stable throughout the study.Conclusion
A 3-month aerobic exercise training was safe and capable of ameliorating the cardiorespiratory capacity and the autonomic function in C-SLE patients.Trial registration
NCT01515163. 相似文献4.
Wen-hui Lu Yu-xun Shi Zheng-lai Ma Guang Wang Langxia Liu Manli Chuai 《Cell cycle (Georgetown, Tex.)》2016,15(13):1742-1754
People have known that autophagy plays a very important role in many physiological and pathological events. But the role of autophagy on embryonic angiogenesis still remains obscure. In this study, we demonstrated that Atg7, Atg8 and Beclin1 were expressed in the plexus vessels of angiogenesis at chick yolk sac membrane and chorioallantoic membrane. Interfering in autophagy with autophagy inducer or inhibitor could restrict the angiogenesis in vivo, which might be driven by the disorder of angiogenesis-related gene expressions, and also lead to embryonic hemorrhage, which was due to imperfection cell junctions in endothelial cells including abnormal expressions of tight junction, adheren junction and desmosome genes. Using HUVECs, we revealed that cell viability and migration ability changed with the alteration of cell autophagy exposed to RAPA or 3-MA. Interestingly, tube formation assay showed that HUVECs ability of tube formation altered with the change of Atg5, Atg7 and Atg8 manipulated by the transfection of their corresponding siRNA or plasmids. Moreover, the lost cell polarity labeled by F-actin and the absenced β-catenin in RAPA-treated and 3-MA-treated cell membrane implied intracellular cytoskeleton alteration was induced by the activation and depression of autophagy. Taken together, our current experimental data reveal that autophagy is really involved in regulating angiogenesis during embryo development. 相似文献
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The ability of two strains of Lactobacillus acidophilus, CRL 640 and CRL 800, to survive and retain their biological activities under frozen storage was determined. Freezing and thawing, as well as frozen storage, damaged the cell membrane, rendering the microorganisms sensitive to sodium chloride and bile salts. Both lactic acid production and proteolytic activity were depressed after 21 days at -20 degreesC, whereas beta-galactosidase activity per cell unit was increased. Cell injury was partially overcome after repair in a salt-rich medium. Copyright 1998 Academic Press. 相似文献
6.
We have investigated the patterns of tissue flow underlying the formation of the primitive streak in the chick embryo. Analysis of time-lapse sequences of brightfield images to extract the tissue velocity field and of fluorescence images of small groups of DiI-labelled cells have shown that epiblast cells move in two large-scale counter-rotating streams, which merge at the site of streak formation. Despite the large-scale tissue flows, individual cells appear to move little relative to their neighbours. As the streak forms, it elongates in both the anterior and posterior directions. Inhibition of actin polymerisation via local application of the inhibitor latrunculin A immediately terminates anterior extension of the streak tip, but does not prevent posterior elongation. Inhibition of actin polymerisation at the base of the streak completely inhibits streak formation, implying that continuous movement of cells into the base of the forming streak is crucial for extension. Analysis of cycling cells in the early embryo shows that cell-cycle progression in the epiblast is quite uniform before the primitive streak forms then decreases in the central epiblast and incipient streak and increases at the boundary between the area pellucida and area opaca during elongation. The cell-cycle inhibitor aphidicolin, at concentrations that completely block cell-cycle progression, permits initial streak formation but arrests development during extension. Our analysis suggests that cell division maintains the cell-flow pattern that supplies the streak with cells from the lateral epiblast, which is critical for epiblast expansion in peripheral areas, but that division does not drive streak formation or the observed tissue flow. 相似文献
7.
Lei J Zhou C Hu H Hu L Zhao M Yang Y Chuai Y Ni J Cai J 《Journal of cellular biochemistry》2012,113(8):2633-2642
Recent studies suggest that mangiferin aglycone (norathyriol) has great potential as a novel radioprotector without any known toxic side effects. In this study, we assessed the protective effects of mangiferin aglycone against radiation-induced injuries on normal human intestinal epithelial cells (HIECs), while using mangiferin as a reference compound. The in vitro experiments showed that pretreatment of either mangiferin aglycone or mangiferin could inhibit cytotoxic effects of ionizing irradiation (IR) on HIECs. Cellular changes were estimated by measuring cell viability, clonogenic surviving rate, and apoptotic rate. Compared to mangiferin, we found mangiferin aglycone had greater radioprotective effects of mangiferin aglycone on HIECs. It has been demonstrated that the cytotoxicity of ionizing radiation relates to its capacity to induce DNA damage. In view of this, we monitored DNA double-strand breaks (DSBs) using γH2AX foci formation to test whether mangiferin aglycone and mangiferin could modulate genotoxic effects of radiation. It shows that mangiferin aglycone could eliminate 46.8% of the total DSBs of the cells exposed to 2 Gy IR, which is significantly better than mangiferin. Complementing earlier results from our group, it appears possible to conclude that mangiferin aglycone presents potential useful effects on IR-induced damage and may be a better radioprotective agent than mangiferin therapeutically. 相似文献
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Tomas ML Eagan Esteban C Gabazza Corina D’Alessandro-Gabazza Paloma Gil-Bernabe Shinya Aoki Jon A Hardie Per S Bakke Peter D Wagner 《Respiratory research》2012,13(1):48