Mingda Jiao

Northeast Normal University, Hsin-ching, Jilin Sheng, China

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Publications (12)18.47 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In higher eukaryotes ribosome production starts at the end of mitosis, increases during G1, is maximal in G2 (Sirri et al., 2000) and stops during prophase (Gébrane-Younès et al., 1997). But the mechanism of the change is still uncovered. Especially in the actively growing mammalian somatic cells usually contain one or several giant fibrillar centres (GFCs) with many tiny fibrillar centre (FCs) (Koberna et al., 2002; Raška et al., 2004; Casafont et al., 2007). The process how the giant fibrillar centre (GFC) and the many tiny fibrillar centres (FCs) were formed is unknown. The present results showed there were processes of FCs fusion in G1 phase and FCs regeneration in S phase respectively in the nucleoli of A 375 cells. A few FCs fused each other in late G1 phase when the process of nucleoli fusion was completed. In S phase, a lot of tiny FCs were regenerated from the periphery of GFC, separated and scattered into nucleolar matrix in late S phase and early G2 phase. The GFC was found to be coexisted with numerous tiny FCs in the nucleolus in G2 phase. The present study provided a new evidence of nucleolar dynamic change during interphase: fibrillar centre (FC) was not to be a stable state subunit of nucleolar compartment but a highly dynamic process that may be the bases of nucleolar morphological architecture organization and its function taking place.
    Micron 03/2013; · 1.88 Impact Factor
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    ABSTRACT: To investigate the correlation between subnucleolar structure and function, the precise distribution and configuration of nucleolar DNA during the cell cycle of Allium sativum were determined using the NAMA-Ur DNA-specific staining technique. We showed that nucleolar DNA is present in two forms: compacted chromatin clumps and a decondensed DNA cloud. The form of the DNA within the nucleolus varied greatly as the cell cycle progressed. During telophase, chromosomes extended into the prenucleolar body. In early G1 phase, DNA was only located in the fibrillar centers in the form of the condensed chromatin clump, while in mid-G1, S and G2 phases, the two forms of DNA were distributed in the fibrillar centers (FC) and dense fibrillar component (DFC). In prophase of mitosis, nucleolar DNA, along with FC and DFC, was linked into a network structure and condensed into a large chromatin clump. The area of the DNA cloud in the dense fibrillar component changed during different phases of the cell cycle. Our results demonstrated that the configuration of nucleolar DNA undergoes a series of decondensations and condensations during the cell cycle to fulfill the function of the nucleoli during the different phases.
    Micron 02/2009; 40(4):449-54. · 1.88 Impact Factor
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    ABSTRACT: The distribution and configurations of nucleolar DNA in Pisum sativum L., Allium sativum L., Triticum aestivum L. were analyzed by specific cytochemical staining using NAMA-Ur. It has been observed that in the nucleoli of different plant species, the DNA occupied different positions in different areas, which may imply a different status and strategy of rDNA transcription. Our results showed irregular clumps of rDNA surrounding FCs in semi-circular formations in P. sativum and T. aestivum, indicating a regular pattern of rDNA distribution and supporting the helix model of rDNA configuration. The rDNA was condensed in some regions and uncondensed in others. Nucleolus-associated chromatin extended from outside the nucleolus to the periphery of the FCs via nucleolar channels, which suggests a possible origin for nucleolar DNA.
    Micron 02/2008; 39(4):405-10. · 1.88 Impact Factor
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    ABSTRACT: In order to get a deeper understanding of the relationship between nucleolus structure and its function, the dynamic change and derivation of FC (fibrillar center) and DFC (dense fibrillar component) through interphase were investigated in HeLa cells synchronized at the ultrastructural level. The results showed that there was a process of FC and DFC derivation in the nucleolus of HeLa cells during interphase. In G1 phase there were a few big FCs in the nucleolus of the HeLa cell. In S phase DFC around the FC got thickened and the configuration of the DFC changed. A lot of tiny FCs were derived from parts of the thickened DFC. We called the FC and DFC formed in G1 phase as primary FC (pri-FC) and primary DFC (pri-DFC) and the FC and DFC derived from the thickened pri-DFC as secondary FC (sec-FC) and secondary DFC (sec-DFC). In G2 phase sec-FC and sec-DFC were gradually separated from pri-DFC and scattered evenly in the nucleolus. Few large pri-FCs coexisted with numerous tiny sec-FCs in the nucleolus of HeLa cells in G2 phase. Based on the results of our observation, we suggest here a model of the dynamic change and the process of derivation of FC and DFC through interphase.
    Cell Biology International 11/2006; 30(10):836-40. · 1.64 Impact Factor
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    ABSTRACT: The distribution and organization of nucleolar DNA in Vicia faba L. was analyzed by specific cytochemical staining using NAMA-Ur. The results showed that nucleolar DNA was distributed in the FCs and at the FC/DFC junctions. Statistical analysis showed that the rRNA genes occupied about one-third of the total dense fibrillar component region. The rDNA was condensed in some regions and uncondensed in others. Nucleolus-associated chromatin extended from outside the nucleolus to the periphery of the FCs via nucleolar channels, suggesting a possible origin for nucleolar DNA.
    Cell Biology International 02/2004; 28(12):845-8. · 1.64 Impact Factor
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    ABSTRACT: Coiled bodies (CBs) are nuclear organelles which were considered as "universal" nuclear structures in eukaryotic cells, but the formation and function of CBs, especially in plant cells, remained unclear. In this article we reported that CBs in meristematic cells of pea are oval to round obstacles in nucleus and in adjacent to nucleolus, often have the same electron density with nucleolus. We found that CBs could be stained by the rRNP preference staining method, but no rDNA was detected in the structure. Furthermore, our results of immunoelectron microscopy showed that several processing factors, include fibrillarin, U3 snoRNA and ITS1, were present in CB. It seems probable that CBs is derived structurally from nucleolus and act as transport, storage and processing subnucleolar organelles.
    Cell Biology International 02/2004; 28(11):825-8. · 1.64 Impact Factor
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    ABSTRACT: The location of rRNA processing was analyzed by using in situ hybridization with ITS1 probe and immunolabeling of anti-fibrillarin mAb in pea (Pisum sativum) root pole cells. The results showed that rRNA processing sites were in dense fibrillar components (DFCs) and granular components (GCs), but not in fibrillar centers (FCs). Low doses of actinomycin D (AMD) treatment can selectively suppress pre-rRNA synthesis but cannot disturb the processing of preformed pre-rRNAs. With AMD treatment prolonged, the density of labeled signals gradually decreased, indicating the preformed pre-rRNAs were gradually processed.
    Science in China Series C Life Sciences 02/2003; 46(1):58-66. · 1.61 Impact Factor
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    ABSTRACT: The location and configuration of nucleolar DNA have not been determined for a long time. In this paper, we have observed the nucleolar ultrastructure and the character of nucleolar DNA inAllium cepa cells by conventional electron microscopy and the cytochemical NAMA-Ur DNA specific staining method. Furthermore, we have properly improved the NAMA-Ur method so as to analyze the location and configuration of nucleolar DNAin situ. Our results indicated that the nucleolar DNA inAllium cepa cells is mainly located at the border between fibrillar centers and dense fibrillar component, especially distributed in the configuration of encircling the fibrillar centers.
    Chinese Science Bulletin 01/2001; 46(1):62-66. · 1.37 Impact Factor
  • W Tao, M Jiao, J He, M He, S Hao
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    ABSTRACT: We observed the ultrastructure of nucleolus in rat liver cells by conventional electron microscopy, and employed cytochemistry NAMA-Ur DNA specific stain method to analyze the distribution and position of nucleolar DNAin situ. The results showed that nucleolar DNA of rat liver cells comes from nucleolus-associated chromatin, and continuously extends in the dense fibrillar component (DFC) of nucleolus, localizes at the periphery of fibrillar center (FC) and in DFC. Furthermore, by employing anti-DNA/RNA hybrid antibodies, we directly and selectively labeled transcription sites of rRNA genes and testified that localization of transcription sites not only to DFC but also to the periphery of FC.
    Science in China Series C Life Sciences 07/2000; 43(3):302-9. · 1.61 Impact Factor
  • M Jiao, X Zeng, X Wang, S Hao
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    ABSTRACT: Nucleoli were isolated from physarum polycephalum, and nucleolar matrix was prepared by digesting the nucleoli respectively with DNase 1, 0.25 mol/L (NH4)2SO4 and 2 mol/L NaCl to remove DNA and most proteins. SDS-PAGE analysis indicated that there were about 20 polypeptides in nucleolar matrix component, including the 37 kD polypeptide which was similar to tropomyosin in molecular weight. The result of indirect immunofluorescence treated with anti-tropomyosin antibody and sheep anti-rabbit IgG antibody labelled with FITC showed that bright fluorescence was observed in the nucleoli and nucleolar matrix, but no bright fluorescence in the controls. Indirect Immunoblotting detection further verified that tropomyosin existed in nucleolar matrix. Protein A-colloidal gold immunoelectron microscopic study showed that there were many gold particles in the specimens labelled with tropomyosin antibody, and there were few gold particles found in the controls. Tropomyosin distributed dispersedly in nucleoli.
    ACTA MICROBIOLOGICA SINICA 11/1999; 39(5):402-7.
  • S Hao, M Jiao, J Zhao, M Xing, B Huang
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    ABSTRACT: This paper studies the process and features of chromosome construction in mitotic prophase cells of Allium cepa. The results showed that a prominent reorganization of chromatin occurred during G2--early prophase. The 250-400 nm thick compact chromatin threads in G2 nuclei began to disorganize into about 30, 100 and 220 nm chromatin fibres which constituted the loosely organized chromosome outlines in early prophase before chromosome condensation. In middle prophase, chromosome condensation was characterized by the formation of many condensed regions (aggregates of chromatin), which increased in size (1-1.5 microns) when prophase proceeded. Meanwhile, the chromatin threads that constituted and connected the condensed regions became increasingly thicker (120-250 nm). In late prophase adjacent condensed regions fused to form cylinder-shaped chromosomes. Based on these observations, we come to the conclusion that the construction of prophase chromosomes is a two-step process, that is, the reorganization and condensation of chromatin. In addition, we report the study of silver-stained, DNA- and histone-depleted prophase chromosomes, describe morphological features of the non-histone protein (NHP) residue in early, middle and late prophase chromosomes, and discuss the roles of NHPs in chromosome construction.
    Chromosoma 11/1994; 103(6):432-40. · 3.34 Impact Factor
  • S. Hao, M. Xing, M. Jiao
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    ABSTRACT: Chromatin-free compartments and their contents were observed in chromosomes of root tip meristematic cells of and . The central chromatin-free compartment of chromosome was usually larger than the peripheral ones. In tranverse section, every chromosome showed peripheral chromatin-free compartments though their number and size varied. In longitudinal section, the central chro matin-free compartments were found to be distributed intermittently along the chromosomal axis. The contents, which showed a granular-fibrillar nature and linked up to the rest of the chromosome, were seen in the central and at least some of the peripheral chromatin-free compartments. A cytochemical study revealed that these contents consisted of ribonucleoprotein granules and fibrils. The contents are a special constituent of the chromosome. The chro matin-free compartments in a chromosome seemed connected with one another and their contents may form a network system which plays a role in the maintenance and stabilization of the higher-order structure of chromosome.
    Cell Biology International Reports. 08/1988;

Publication Stats

38 Citations
18.47 Total Impact Points

Institutions

  • 1988–2013
    • Northeast Normal University
      • The Institute of Genetics and Cytology
      Hsin-ching, Jilin Sheng, China
  • 2008
    • Huazhong Agricultural University
      • College of Life Science and Technology
      Wuhan, Hubei, China
  • 2000–2001
    • Changchun Normal University
      Hsin-ching, Jilin Sheng, China