Restriction enzyme digestion of total genomic DNA of two chro-mosome type Paragonimus westermani showed the presence of homologus highlyrepeated DNA in diploid and triploid forms. Southern blot analysis providedfurthe...Restriction enzyme digestion of total genomic DNA of two chro-mosome type Paragonimus westermani showed the presence of homologus highlyrepeated DNA in diploid and triploid forms. Southern blot analysis providedfurther evidence that the distribution of restriction enzyme sites (with 3enzymes) on repeated DNA of both was similar. But with Pst Ⅰ、Dde Ⅰ、Hae Ⅲand Hpa Ⅱ. They revealed polymorphism which also occured individually ineach form tested separatedly with hybridization technique. Mutation of recog-nize sites by enzymes, which is resulted from the alternation of gene sequance,has occured during evolution. Additionally, it is probably possible, based on PstⅠand Dde Ⅰdigest pattern to distinguish between diploid and triploid Parag-onimus westermani and group the Paragonimus simply and rapidly.展开更多
本文报道用原位缺口翻译法,研究男用节育药醋酸棉酚和雷公藤总甙(GTW)对C3H-10 T 1/2小鼠成纤维细胞DNA的作用。结果表明,在较高浓度的醋酸棉酚或GTW(2～3μg/ml)作用4小时,细胞核中显示的银颗粒较多,如阳性对照组的N-甲基-N′-硝基-亚...本文报道用原位缺口翻译法,研究男用节育药醋酸棉酚和雷公藤总甙(GTW)对C3H-10 T 1/2小鼠成纤维细胞DNA的作用。结果表明,在较高浓度的醋酸棉酚或GTW(2～3μg/ml)作用4小时,细胞核中显示的银颗粒较多,如阳性对照组的N-甲基-N′-硝基-亚硝基胍(MNNG)组;在中等浓度的(0.5～1μg/ml)作用下,银颗粒显著地少得多;在较低浓度的醋酸棉酚或GTW作用下(0.1～0.3μg/ml),细胞核中呈现的银颗粒与阴性对照组相似。与原位缺口翻译实验相对应,集落形成试验表明,在高浓度醋酸棉酚或GTW作用下,细胞失去繁殖的能力;而在中等或较低浓度的药物作用下,仍有较高的集落形成率。这些观察表明,高浓度的醋酸棉酚或GTW对细胞DNA有严重的损伤作用,而在中等浓度的药物作用下,DNA受到某种程度的损伤,但可修复;低浓度的醋酸棉酚或GTW对细胞DNA无明显的损伤作用,本文对这些结果的意义进行了简要的讨论。展开更多
Human polymorphonuclear leukocytes (PMN) have been reported to completely lack of DNA-dependent protein kinase (DNA-PK) which is composed of Ku protein and the catalytic subunit DNA-PKcs, needed for nonhomologous end-...Human polymorphonuclear leukocytes (PMN) have been reported to completely lack of DNA-dependent protein kinase (DNA-PK) which is composed of Ku protein and the catalytic subunit DNA-PKcs, needed for nonhomologous end-joining (NHEJ) of DNA double-strand breaks. Promyelocytic HL-60 cells express a variant form of Ku resulting in enhanced radiation sensitivity. This raises the question if low efficiency of NHEJ, instrumental for the cellular repair of oxidative damage, is a normal characteristic of myeloid differentiation. Here we confirmed the complete lack of DNAPK in P MN protein extracts, and the expression of the truncated Ku86 variant form in HL-60. However, this degradation of DNA-PK was shown to be due to a DNA-PK-degrading protease in PMN and HL-60. In addition, by using a protease-resistant whole cell assay, both Ku86 and DNA-PKcs could be demonstrated in PMN, suggesting the previously reported absence in PMN of DNA-PK to be an artefact. The levels of Ku86 and DNA-PKcs were much reduced in PMN, as compared with that of the lymphocytes, whereas HL-60 displayed a markedly elevated DNA-PK concentration.In conclusion, our findings provide evidence of reduced, not depleted expression of DNA-PK during the mature stages of myeloid differentiation.展开更多
文摘Restriction enzyme digestion of total genomic DNA of two chro-mosome type Paragonimus westermani showed the presence of homologus highlyrepeated DNA in diploid and triploid forms. Southern blot analysis providedfurther evidence that the distribution of restriction enzyme sites (with 3enzymes) on repeated DNA of both was similar. But with Pst Ⅰ、Dde Ⅰ、Hae Ⅲand Hpa Ⅱ. They revealed polymorphism which also occured individually ineach form tested separatedly with hybridization technique. Mutation of recog-nize sites by enzymes, which is resulted from the alternation of gene sequance,has occured during evolution. Additionally, it is probably possible, based on PstⅠand Dde Ⅰdigest pattern to distinguish between diploid and triploid Parag-onimus westermani and group the Paragonimus simply and rapidly.
文摘本文报道用原位缺口翻译法,研究男用节育药醋酸棉酚和雷公藤总甙(GTW)对C3H-10 T 1/2小鼠成纤维细胞DNA的作用。结果表明,在较高浓度的醋酸棉酚或GTW(2～3μg/ml)作用4小时,细胞核中显示的银颗粒较多,如阳性对照组的N-甲基-N′-硝基-亚硝基胍(MNNG)组;在中等浓度的(0.5～1μg/ml)作用下,银颗粒显著地少得多;在较低浓度的醋酸棉酚或GTW作用下(0.1～0.3μg/ml),细胞核中呈现的银颗粒与阴性对照组相似。与原位缺口翻译实验相对应,集落形成试验表明,在高浓度醋酸棉酚或GTW作用下,细胞失去繁殖的能力;而在中等或较低浓度的药物作用下,仍有较高的集落形成率。这些观察表明,高浓度的醋酸棉酚或GTW对细胞DNA有严重的损伤作用,而在中等浓度的药物作用下,DNA受到某种程度的损伤,但可修复;低浓度的醋酸棉酚或GTW对细胞DNA无明显的损伤作用,本文对这些结果的意义进行了简要的讨论。
文摘Human polymorphonuclear leukocytes (PMN) have been reported to completely lack of DNA-dependent protein kinase (DNA-PK) which is composed of Ku protein and the catalytic subunit DNA-PKcs, needed for nonhomologous end-joining (NHEJ) of DNA double-strand breaks. Promyelocytic HL-60 cells express a variant form of Ku resulting in enhanced radiation sensitivity. This raises the question if low efficiency of NHEJ, instrumental for the cellular repair of oxidative damage, is a normal characteristic of myeloid differentiation. Here we confirmed the complete lack of DNAPK in P MN protein extracts, and the expression of the truncated Ku86 variant form in HL-60. However, this degradation of DNA-PK was shown to be due to a DNA-PK-degrading protease in PMN and HL-60. In addition, by using a protease-resistant whole cell assay, both Ku86 and DNA-PKcs could be demonstrated in PMN, suggesting the previously reported absence in PMN of DNA-PK to be an artefact. The levels of Ku86 and DNA-PKcs were much reduced in PMN, as compared with that of the lymphocytes, whereas HL-60 displayed a markedly elevated DNA-PK concentration.In conclusion, our findings provide evidence of reduced, not depleted expression of DNA-PK during the mature stages of myeloid differentiation.
