The chromatin folding patterns in air and liquid were studied by atomicforce microscopy (AFM). A gentle water-air interface method was adopted to spreadchromatin from interphase nucleus of chicken erythrocyte. The chr...The chromatin folding patterns in air and liquid were studied by atomicforce microscopy (AFM). A gentle water-air interface method was adopted to spreadchromatin from interphase nucleus of chicken erythrocyte. The chromatin was ah-sorbed on APS-Inica surfaCe and studied with AFM. Beads-on-a-string were observedand many higher-order structures such as superbeads with dimensions 40-60urn indiameter and 4-7 urn in height were found to string together to make chromatin fibers.When sample spreading and absorbing time were shortened, higher-order chromatinfibers with 60-120 urn in width were observed in air as well as under water environment. These chromatin structures may reflect chromatin folding patterns in the livingcells.展开更多
A modified "dynamic molecular combing"(DMC) technique used for stretching double-stranded DNA is reported. DNA molecules were stretched on the silanized mica surface by this technique, its speed being precis...A modified "dynamic molecular combing"(DMC) technique used for stretching double-stranded DNA is reported. DNA molecules were stretched on the silanized mica surface by this technique, its speed being precisely controlled with a computer. This approach combined the precise DNA stretching method with high resolution AFM imaging at nanometer scale, thus making it useful for DNA alignment manipulation and subsequent gene research.展开更多
DNA molecules were stretched on silanized mica surface with the molecular combing technique, and detected with fluorescence microscopy and atomic force microscopy. Meantime, DNA molecules were stretched with a modifie...DNA molecules were stretched on silanized mica surface with the molecular combing technique, and detected with fluorescence microscopy and atomic force microscopy. Meantime, DNA molecules were stretched with a modified dynamic molecular combing technique and studied with atomic force microscopy. The results indicate that, compared with the dynamic molecular combing technique, the modified dynamic molecular combing technique has advantages of less-sample demand and less contamination to sample; as compared with the molecular combing technique, it has better aligning effect and reproducibility. Combination of this kind of DNA molecular manipulating technique with the single DNA molecule detecting technique by atomic force microscopy and fluorescence microscopy will play an important role in the basic research of molecular dynamics and the application of gene research.展开更多
A method of constructing restriction map by optical mapping and single molecule fluorescent microscopy is described. DNA molecules were aligned and adsorbed on a glass coverslip surface by a modified 'molecular co...A method of constructing restriction map by optical mapping and single molecule fluorescent microscopy is described. DNA molecules were aligned and adsorbed on a glass coverslip surface by a modified 'molecular combing' technique, and then the surface-immobilized DNAs were cleaved in situ with a restriction endonuclease. Individual DNA molecules digested by the endonuclease EcoR I were observable with fluorescent microscopy. Using optical mapping, a physical map of a rice bacterial artificial chro-mosome clone was constructed. This method will facilitate genomic mapping and tracing the dynamic process in real time at a single molecule level with fluorescence microscopy.展开更多
文摘The chromatin folding patterns in air and liquid were studied by atomicforce microscopy (AFM). A gentle water-air interface method was adopted to spreadchromatin from interphase nucleus of chicken erythrocyte. The chromatin was ah-sorbed on APS-Inica surfaCe and studied with AFM. Beads-on-a-string were observedand many higher-order structures such as superbeads with dimensions 40-60urn indiameter and 4-7 urn in height were found to string together to make chromatin fibers.When sample spreading and absorbing time were shortened, higher-order chromatinfibers with 60-120 urn in width were observed in air as well as under water environment. These chromatin structures may reflect chromatin folding patterns in the livingcells.
文摘A modified "dynamic molecular combing"(DMC) technique used for stretching double-stranded DNA is reported. DNA molecules were stretched on the silanized mica surface by this technique, its speed being precisely controlled with a computer. This approach combined the precise DNA stretching method with high resolution AFM imaging at nanometer scale, thus making it useful for DNA alignment manipulation and subsequent gene research.
文摘DNA molecules were stretched on silanized mica surface with the molecular combing technique, and detected with fluorescence microscopy and atomic force microscopy. Meantime, DNA molecules were stretched with a modified dynamic molecular combing technique and studied with atomic force microscopy. The results indicate that, compared with the dynamic molecular combing technique, the modified dynamic molecular combing technique has advantages of less-sample demand and less contamination to sample; as compared with the molecular combing technique, it has better aligning effect and reproducibility. Combination of this kind of DNA molecular manipulating technique with the single DNA molecule detecting technique by atomic force microscopy and fluorescence microscopy will play an important role in the basic research of molecular dynamics and the application of gene research.
基金Thiswork was supported by the Fund of the Chinese Academy of Sciences (Grant No. Kj-951-603).
文摘A method of constructing restriction map by optical mapping and single molecule fluorescent microscopy is described. DNA molecules were aligned and adsorbed on a glass coverslip surface by a modified 'molecular combing' technique, and then the surface-immobilized DNAs were cleaved in situ with a restriction endonuclease. Individual DNA molecules digested by the endonuclease EcoR I were observable with fluorescent microscopy. Using optical mapping, a physical map of a rice bacterial artificial chro-mosome clone was constructed. This method will facilitate genomic mapping and tracing the dynamic process in real time at a single molecule level with fluorescence microscopy.
