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Sample records for cell nucleolus

  1. Connecting the nucleolus to the cell cycle and human disease.

    Science.gov (United States)

    Tsai, Robert Y L; Pederson, Thoru

    2014-08-01

    Long known as the center of ribosome synthesis, the nucleolus is connected to cell cycle regulation in more subtle ways. One is a surveillance system that reacts promptly when rRNA synthesis or processing is impaired, halting cell cycle progression. Conversely, the nucleolus also acts as a first-responder to growth-related stress signals. Here we review emerging concepts on how these "infraribosomal" links between the nucleolus and cell cycle progression operate in both forward and reverse gears. We offer perspectives on how new cancer therapeutic designs that target this infraribosomal mode of cell growth control may shape future clinical progress.

  2. The nucleolus: a paradigm for cell proliferation and aging.

    Science.gov (United States)

    Comai, L

    1999-12-01

    The nucleolus is the cellular site of ribosome biosynthesis. At this site, active ribosomal DNA (rDNA) genes are rapidly transcribed by RNA polymerase I (pol I) molecules. Recent advances in our understanding of the pol I transcription system have indicated that regulation of ribosomal RNA (rRNA) synthesis is a critical factor in cell growth. Importantly, the same signaling networks that control cell growth and proliferation and are deregulated in cancer appear to control pol I transcription. Therefore, the study of the biochemical basis for growth regulation of pol I transcription can provide basic information about the nuclear signaling network. Hopefully, this information may facilitate the search for drugs that can inhibit the growth of tumor cells by blocking pol I activation. In addition to its function in ribosome biogenesis, recent studies have revealed the prominent role of the nucleolus in cell senescence. These findings have stimulated a new wave of research on the functional relationship between the nucleolus and aging. The aim of this review is to provide an overview of some current topics in the area of nucleolus biology, and it has been written for a general readership.

  3. The nucleolus: a paradigm for cell proliferation and aging

    Directory of Open Access Journals (Sweden)

    Comai L.

    1999-01-01

    Full Text Available The nucleolus is the cellular site of ribosome biosynthesis. At this site, active ribosomal DNA (rDNA genes are rapidly transcribed by RNA polymerase I (pol I molecules. Recent advances in our understanding of the pol I transcription system have indicated that regulation of ribosomal RNA (rRNA synthesis is a critical factor in cell growth. Importantly, the same signaling networks that control cell growth and proliferation and are deregulated in cancer appear to control pol I transcription. Therefore, the study of the biochemical basis for growth regulation of pol I transcription can provide basic information about the nuclear signaling network. Hopefully, this information may facilitate the search for drugs that can inhibit the growth of tumor cells by blocking pol I activation. In addition to its function in ribosome biogenesis, recent studies have revealed the prominent role of the nucleolus in cell senescence. These findings have stimulated a new wave of research on the functional relationship between the nucleolus and aging. The aim of this review is to provide an overview of some current topics in the area of nucleolus biology, and it has been written for a general readership.

  4. The cell's nucleolus: an emerging target for chemotherapeutic intervention.

    Science.gov (United States)

    Pickard, Amanda J; Bierbach, Ulrich

    2013-09-01

    The transient nucleolus plays a central role in the up-regulated synthesis of ribosomal RNA (rRNA) to sustain ribosome biogenesis, a hallmark of aberrant cell growth. This function, in conjunction with its unique pathohistological features in malignant cells and its ability to mediate apoptosis, renders this sub-nuclear structure a potential target for chemotherapeutic agents. In this Minireview, structurally and functionally diverse small molecules are discussed that have been reported to either interact with the nucleolus directly or perturb its function indirectly by acting on its dynamic components. These molecules include all major classes of nucleic-acid-targeted agents, antimetabolites, kinase inhibitors, anti-inflammatory drugs, natural product antibiotics, oligopeptides, as well as nanoparticles. Together, these molecules are invaluable probes of structure and function of the nucleolus. They also provide a unique opportunity to develop novel strategies for more selective and therefore better-tolerated chemotherapeutic intervention. In this regard, inhibition of RNA polymerase-I-mediated rRNA synthesis appears to be a promising mechanism for killing cancer cells. The recent development of molecules targeted at G-quadruplex-forming rRNA gene sequences, which are currently undergoing clinical trials, seems to attest to the success of this approach.

  5. Visualization of the Nucleolus in Living Cells with Cell-Penetrating Fluorescent Peptides.

    Science.gov (United States)

    Martin, Robert M; Herce, Henry D; Ludwig, Anne K; Cardoso, M Cristina

    2016-01-01

    The nucleolus is the hallmark of nuclear compartmentalization and has been shown to exert multiple roles in cellular metabolism besides its main function as the place of ribosomal RNA synthesis and assembly of ribosomes. The nucleolus plays also a major role in nuclear organization as the largest compartment within the nucleus. The prominent structure of the nucleolus can be detected using contrast light microscopy providing an approximate localization of the nucleolus, but this approach does not allow to determine accurately the three-dimensional structure of the nucleolus in cells and tissues. Immunofluorescence staining with antibodies specific to nucleolar proteins albeit very useful is time consuming, normally antibodies recognize their epitopes only within a small range of species and is applicable only in fixed cells. Here, we present a simple method to selectively and accurately label this ubiquitous subnuclear compartment in living cells of a large range of species using a fluorescently labeled cell-penetrating peptide.

  6. Proteomic profiling of the human T-cell nucleolus.

    Science.gov (United States)

    Jarboui, Mohamed Ali; Wynne, Kieran; Elia, Giuliano; Hall, William W; Gautier, Virginie W

    2011-12-01

    The nucleolus, site of ribosome biogenesis, is a dynamic subnuclear organelle involved in diverse cellular functions. The size, number and organisation of nucleoli are cell-specific and while it remains to be established, the nucleolar protein composition would be expected to reflect lineage-specific transcriptional regulation of rDNA genes and have cell-type functional components. Here, we describe the first characterisation of the human T-cell nucleolar proteome. Using the Jurkat T-cell line and a reproducible organellar proteomic approach, we identified 872 nucleolar proteins. In addition to ribosome biogenesis and RNA processing networks, network modeling and topological analysis of nucleolar proteome revealed distinct macromolecular complexes known to orchestrate chromatin structure and to contribute to the regulation of gene expression, replication, recombination and repair, and chromosome segregation. Furthermore, among our dataset, we identified proteins known to functionally participate in T-cell biology, including RUNX1, ILF3, ILF2, STAT3, LSH, TCF-1, SATB1, CTCF, HMGB3, BCLAF1, FX4L1, ZAP70, TIAM1, RAC2, THEMIS, LCP1, RPL22, TOPK, RETN, IFI-16, MCT-1, ISG15, and 14-3-3τ, which support cell-specific composition of the Jurkat nucleolus. Subsequently, the nucleolar localisation of RUNX1, ILF3, STAT3, ZAP70 and RAC2 was further validated by Western Blot analysis and immunofluorescence microscopy. Overall, our T-cell nucleolar proteome dataset not only further expands the existing repertoire of the human nucleolar proteome but support a cell type-specific composition of the nucleolus in T cell and highlights the potential roles of the nucleoli in lymphocyte biology.

  7. Plant cell nucleolus as a hot spot for iron.

    Science.gov (United States)

    Roschzttardtz, Hannetz; Grillet, Louis; Isaure, Marie-Pierre; Conéjéro, Geneviève; Ortega, Richard; Curie, Catherine; Mari, Stéphane

    2011-08-12

    Many central metabolic processes require iron as a cofactor and take place in specific subcellular compartments such as the mitochondrion or the chloroplast. Proper iron allocation in the different organelles is thus critical to maintain cell function and integrity. To study the dynamics of iron distribution in plant cells, we have sought to identify the different intracellular iron pools by combining three complementary imaging approaches, histochemistry, micro particle-induced x-ray emission, and synchrotron radiation micro X-ray fluorescence. Pea (Pisum sativum) embryo was used as a model in this study because of its large cell size and high iron content. Histochemical staining with ferrocyanide and diaminobenzidine (Perls/diaminobenzidine) strongly labeled a unique structure in each cell, which co-labeled with the DNA fluorescent stain DAPI, thus corresponding to the nucleus. The unexpected presence of iron in the nucleus was confirmed by elemental imaging using micro particle-induced x-ray emission. X-ray fluorescence on cryo-sectioned embryos further established that, quantitatively, the iron concentration found in the nucleus was higher than in the expected iron-rich organelles such as plastids or vacuoles. Moreover, within the nucleus, iron was particularly accumulated in a subcompartment that was identified as the nucleolus as it was shown to transiently disassemble during cell division. Taken together, our data uncover an as yet unidentified although abundant iron pool in the cell, which is located in the nuclei of healthy, actively dividing plant tissues. This result paves the way for the discovery of a novel cellular function for iron related to nucleus/nucleolus-associated processes.

  8. Perturbation of nucleo-cytoplasmic transport affects size of nucleus and nucleolus in human cells.

    Science.gov (United States)

    Ganguly, Abira; Bhattacharjee, Chumki; Bhave, Madhura; Kailaje, Vaishali; Jain, Bhawik K; Sengupta, Isha; Rangarajan, Annapoorni; Bhattacharyya, Dibyendu

    2016-03-01

    Size regulation of human cell nucleus and nucleolus are poorly understood subjects. 3D reconstruction of live image shows that the karyoplasmic ratio (KR) increases by 30-80% in transformed cell lines compared to their immortalized counterpart. The attenuation of nucleo-cytoplasmic transport causes the KR value to increase by 30-50% in immortalized cell lines. Nucleolus volumes are significantly increased in transformed cell lines and the attenuation of nucleo-cytoplasmic transport causes a significant increase in the nucleolus volume of immortalized cell lines. A cytosol and nuclear fraction swapping experiment emphasizes the potential role of unknown cytosolic factors in nuclear and nucleolar size regulation.

  9. Structures of nucleolus and transcription sites of rRNA genes in rat liver cells

    Institute of Scientific and Technical Information of China (English)

    陶伟; 焦明大; 赫杰; 何孟元; 郝水

    2000-01-01

    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 DNA in 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.

  10. Structures of nucleolus and transcription sites of rRNA genes in rat liver cells

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    We observed the ultrastructure of nucleolus in rat liver cells by conventional electronmicroscopy, and employed cytochemistry NAMA-Ur DNA specific stain method to analyze the distributionand position of nucleolar DNA in situ. The results showed that nucleolar DNA of rat livercells comes from nucleolus-associated chromatin, and continuously extends in the dense fibrillarcomponent (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 transcriptionsites of rRNA genes and testified that localization of transcription sites not only to DFC butalso to the periphery of FC.

  11. The nucleolus and herpesviral usurpation.

    Science.gov (United States)

    Ni, Liwen; Wang, Shuai; Zheng, Chunfu

    2012-12-01

    The nucleolus is a distinct subnuclear compartment known as the site for ribosome biogenesis in eukaryotes. Consequently, the nucleolus is also proposed to function in cell-cycle control, stress sensing and senescence, as well as in viral infection. An increasing number of viral proteins have been found to localize to the nucleolus. In this article, we review the current understanding of the functions of the nucleolus, the molecular mechanism of cellular and viral protein targeting to the nucleolus and the functional roles of the nucleolus during viral infection with a specific focus on the herpesvirus family.

  12. NSA2, a novel nucleolus protein regulates cell proliferation and cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Heyu [Department of Immunology, School of Basic Medical Sciences, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Human Disease Genomics Center, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Ma, Xi [Department of Immunology, School of Basic Medical Sciences, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Human Disease Genomics Center, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); State Key Lab of Animal Nutrition, China Agricultural University, No. 2 Yuanmingyuan West Road, Beijing 100193 (China); Shi, Taiping [Chinese National Human Genome Center, Beijing. 3-707 North YongChang Road BDA, Beijing 100176 (China); Song, Quansheng [Department of Immunology, School of Basic Medical Sciences, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Human Disease Genomics Center, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Zhao, Hongshan, E-mail: hongshan@bjmu.edu.cn [Department of Immunology, School of Basic Medical Sciences, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Human Disease Genomics Center, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Ma, Dalong [Department of Immunology, School of Basic Medical Sciences, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China); Human Disease Genomics Center, Peking University, No. 38 Xueyuan Road, Beijing 100191 (China)

    2010-01-01

    NSA2 (Nop seven-associated 2) was previously identified in a high throughput screen of novel human genes associated with cell proliferation, and the NSA2 protein is evolutionarily conserved across different species. In this study, we revealed that NSA2 is broadly expressed in human tissues and cultured cell lines, and located in the nucleolus of the cell. Both of the putative nuclear localization signals (NLSs) of NSA2, also overlapped with nucleolar localization signals (NoLSs), are capable of directing nucleolar accumulation. Moreover, over-expression of the NSA2 protein promoted cell growth in different cell lines and regulated the G1/S transition in the cell cycle. SiRNA silencing of the NSA2 transcript attenuated the cell growth and dramatically blocked the cell cycle in G1/S transition. Our results demonstrated that NSA2 is a nucleolar protein involved in cell proliferation and cell cycle regulation.

  13. Midkine accumulated in nucleolus of HepG2 cells involved in rRNA transcription

    Institute of Scientific and Technical Information of China (English)

    Li-Cheng Dai; Jian-Zhong Shao; Li-Shan Min; Yong-Tao Xiao; Li-Xin Xiang; Zhi-Hong Ma

    2008-01-01

    AIM: To invesgate the ultrastructural location of midkine (MK) in nucleolus and function corresponding to its location. METHODS: To investigate the ultrastructural location of MK in nucleolus with immunoelectronic microscopy. To study the role that MK plays in ribosomal biogenesis by real-time PCR. The effect of MK on anti-apoptotic activity of HepG2 cells was studied with FITC-conjugated annexin V and propidium iodide PI double staining through FACS assay. RESULTS: MK mainly localized in the granular component (GC), dense fibrillar component (DFC) and the border between the DF-C and fibrillar center (FC). The production of 45S precursor rRNA level was decreased significantly in the presence of IK antisense oligonucleotide in the HepG2 cells. Furthermore, it was found that exogenous MK could protect HepG2 from apoptosis significantly. CONCLUSION: NK was constitutively translocated to the nucleolus of HepG2 cells, where it accumulated and mostly distributed at DFC, GC components and at the region between FC and DFC, MK played an important role in rRNA transcription, ribosome biogenesis, and cell proliferation in HepG2 cells. MK might serve as a molecular target for therapeutic intervention of human carcinomas.

  14. High-Throughput Live-Cell Microscopy Analysis of Association Between Chromosome Domains and the Nucleolus in S. cerevisiae.

    Science.gov (United States)

    Wang, Renjie; Normand, Christophe; Gadal, Olivier

    2016-01-01

    Spatial organization of the genome has important impacts on all aspects of chromosome biology, including transcription, replication, and DNA repair. Frequent interactions of some chromosome domains with specific nuclear compartments, such as the nucleolus, are now well documented using genome-scale methods. However, direct measurement of distance and interaction frequency between loci requires microscopic observation of specific genomic domains and the nucleolus, followed by image analysis to allow quantification. The fluorescent repressor operator system (FROS) is an invaluable method to fluorescently tag DNA sequences and investigate chromosome position and dynamics in living cells. This chapter describes a combination of methods to define motion and region of confinement of a locus relative to the nucleolus in cell's nucleus, from fluorescence acquisition to automated image analysis using two dedicated pipelines.

  15. Absence of nucleolus formation in raccoon dog-porcine interspecies somatic cell nuclear transfer embryos results in embryonic developmental failure.

    Science.gov (United States)

    Jeon, Yubyeol; Nam, Yeong-Hee; Cheong, Seung-A; Kwak, Seong-Sung; Lee, Eunsong; Hyun, Sang-Hwan

    2016-08-25

    Interspecies somatic cell nuclear transfer (iSCNT) can be a solution for preservation of endangered species that have limited oocytes. It has been reported that blastocyst production by iSCNT is successful even if the genetic distances between donors and recipients are large. In particular, domestic pig oocytes can support the development of canine to porcine iSCNT embryos. Therefore, we examined whether porcine oocytes may be suitable recipient oocytes for Korean raccoon dog iSCNT. We investigated the effects of trichostatin A (TSA) treatment on iSCNT embryo developmental patterns and nucleolus formation. Enucleated porcine oocytes were fused with raccoon dog fibroblasts by electrofusion and cleavage, and blastocyst development and nucleolus formation were evaluated. To our knowledge, this study is the first in which raccoon dog iSCNT was performed using porcine oocytes; we found that 68.5% of 158 iSCNT embryos had the ability to cleave. However, these iSCNT embryos did not develop past the 4-cell stage. Treatment with TSA did not affect iSCNT embryonic development; moreover, the nuclei failed to form nucleoli at 48 and 72 h post-activation (hpa). In contrast, pig SCNT embryos of the control group showed 18.8% and 87.9% nucleolus formation at 48 and 72 hpa, respectively. Our results demonstrated that porcine cytoplasts efficiently supported the development of raccoon dog iSCNT embryos to the 4-cell stage, the stage of porcine embryonic genome activation (EGA); however, these embryos failed to reach the blastocyst stage and showed defects in nucleolus formation.

  16. Absence of nucleolus formation in raccoon dog-porcine interspecies somatic cell nuclear transfer embryos results in embryonic developmental failure

    Science.gov (United States)

    JEON, Yubyeol; NAM, Yeong-Hee; CHEONG, Seung-A; KWAK, Seong-Sung; LEE, Eunsong; HYUN, Sang-Hwan

    2016-01-01

    Interspecies somatic cell nuclear transfer (iSCNT) can be a solution for preservation of endangered species that have limited oocytes. It has been reported that blastocyst production by iSCNT is successful even if the genetic distances between donors and recipients are large. In particular, domestic pig oocytes can support the development of canine to porcine iSCNT embryos. Therefore, we examined whether porcine oocytes may be suitable recipient oocytes for Korean raccoon dog iSCNT. We investigated the effects of trichostatin A (TSA) treatment on iSCNT embryo developmental patterns and nucleolus formation. Enucleated porcine oocytes were fused with raccoon dog fibroblasts by electrofusion and cleavage, and blastocyst development and nucleolus formation were evaluated. To our knowledge, this study is the first in which raccoon dog iSCNT was performed using porcine oocytes; we found that 68.5% of 158 iSCNT embryos had the ability to cleave. However, these iSCNT embryos did not develop past the 4-cell stage. Treatment with TSA did not affect iSCNT embryonic development; moreover, the nuclei failed to form nucleoli at 48 and 72 h post-activation (hpa). In contrast, pig SCNT embryos of the control group showed 18.8% and 87.9% nucleolus formation at 48 and 72 hpa, respectively. Our results demonstrated that porcine cytoplasts efficiently supported the development of raccoon dog iSCNT embryos to the 4-cell stage, the stage of porcine embryonic genome activation (EGA); however, these embryos failed to reach the blastocyst stage and showed defects in nucleolus formation. PMID:27064112

  17. Aggregation of Ribosomal Protein S6 at Nucleolus Is Cell Cycle-Controlled and Its Function in Pre-rRNA Processing Is Phosphorylation Dependent.

    Science.gov (United States)

    Zhang, Duo; Chen, Hui-Peng; Duan, Hai-Feng; Gao, Li-Hua; Shao, Yong; Chen, Ke-Yan; Wang, You-Liang; Lan, Feng-Hua; Hu, Xian-Wen

    2016-07-01

    Ribosomal protein S6 (rpS6) has long been regarded as one of the primary r-proteins that functions in the early stage of 40S subunit assembly, but its actual role is still obscure. The correct forming of 18S rRNA is a key step in the nuclear synthesis of 40S subunit. In this study, we demonstrate that rpS6 participates in the processing of 30S pre-rRNA to 18S rRNA only when its C-terminal five serines are phosphorylated, however, the process of entering the nucleus and then targeting the nucleolus does not dependent its phosphorylation. Remarkably, we also find that the aggregation of rpS6 at the nucleolus correlates to the phasing of cell cycle, beginning to concentrate in the nucleolus at later S phase and disaggregate at M phase. J. Cell. Biochem. 117: 1649-1657, 2016. © 2015 Wiley Periodicals, Inc.

  18. A nucleolus-predominant piggyBac transposase, NP-mPB, mediates elevated transposition efficiency in mammalian cells.

    Science.gov (United States)

    Hong, Jin-Bon; Chou, Fu-Ju; Ku, Amy T; Fan, Hsiang-Hsuan; Lee, Tung-Lung; Huang, Yung-Hsin; Yang, Tsung-Lin; Su, I-Chang; Yu, I-Shing; Lin, Shu-Wha; Chien, Chung-Liang; Ho, Hong-Nerng; Chen, You-Tzung

    2014-01-01

    PiggyBac is a prevalent transposon system used to deliver transgenes and functionally explore the mammalian untouched genomic territory. The important features of piggyBac transposon are the relatively low insertion site preference and the ability of seamless removal from genome, which allow its potential uses in functional genomics and regenerative medicine. Efforts to increase its transposition efficiency in mammals were made through engineering the corresponding transposase (PBase) codon usage to enhance its expression level and through screening for mutant PBase variants with increased enzyme activity. To improve the safety for its potential use in regenerative medicine applications, site-specific transposition was achieved by using engineered zinc finger- and Gal4-fused PBases. An excision-prone PBase variant has also been successfully developed. Here we describe the construction of a nucleolus-predominant PBase, NP-mPB, by adding a nucleolus-predominant (NP) signal peptide from HIV-1 TAT protein to a mammalian codon-optimized PBase (mPB). Although there is a predominant fraction of the NP-mPB-tGFP fusion proteins concentrated in the nucleoli, an insertion site preference toward nucleolar organizer regions is not detected. Instead a 3-4 fold increase in piggyBac transposition efficiency is reproducibly observed in mouse and human cells.

  19. A phosphorescent silver(I)-gold (I) cluster complex that specifically lights up the nucleolus of living cells with FLIM imaging.

    Science.gov (United States)

    Chen, Min; Lei, Zhen; Feng, Wei; Li, Chunyan; Wang, Quan-Ming; Li, Fuyou

    2013-06-01

    The phosphorescent silver(I)-gold(I) cluster complex [CAu6Ag2(dppy)6](BF4)4 (N1) selectively stains the nucleolus, with a much lower uptake in the nucleus and cytoplasm, and exhibits excellent photostability. This Ag-Au cluster, which has a photoluminescent lifetime of microseconds, is particularly attractive as a probe in applications of time-gated microscopy. Investigation of the pathway of cellular entry indicated that N1 permeates the outer membrane and nuclear membrane of living cells through an energy-dependent and non-endocytic route within 10 min. High concentrations of N1 in the nucleolus have been quantified by inductively coupled plasma atomic emission spectroscopy (ICP-AES) and transmission electron microscopy coupled with an energy dispersive X-ray analysis (TEM-EDXA), which also helped to elucidate the mechanism of the specific staining. Intracellular selective staining may be correlated with the microenvironment of the nucleolus, which is consistent with experiments conducted at different phases of the cell cycle. These results prove that N1 is a very attractive phosphorescent staining reagent for visualizing the nucleolus of living cells.

  20. NOA36 protein contains a highly conserved nucleolar localization signal capable of directing functional proteins to the nucleolus, in mammalian cells.

    Science.gov (United States)

    de Melo, Ivan S; Jimenez-Nuñez, Maria D; Iglesias, Concepción; Campos-Caro, Antonio; Moreno-Sanchez, David; Ruiz, Felix A; Bolívar, Jorge

    2013-01-01

    NOA36/ZNF330 is an evolutionarily well-preserved protein present in the nucleolus and mitochondria of mammalian cells. We have previously reported that the pro-apoptotic activity of this protein is mediated by a characteristic cysteine-rich domain. We now demonstrate that the nucleolar localization of NOA36 is due to a highly-conserved nucleolar localization signal (NoLS) present in residues 1-33. This NoLS is a sequence containing three clusters of two or three basic amino acids. We fused the amino terminal of NOA36 to eGFP in order to characterize this putative NoLS. We show that a cluster of three lysine residues at positions 3 to 5 within this sequence is critical for the nucleolar localization. We also demonstrate that the sequence as found in human is capable of directing eGFP to the nucleolus in several mammal, fish and insect cells. Moreover, this NoLS is capable of specifically directing the cytosolic yeast enzyme polyphosphatase to the target of the nucleolus of HeLa cells, wherein its enzymatic activity was detected. This NoLS could therefore serve as a very useful tool as a nucleolar marker and for directing particular proteins to the nucleolus in distant animal species.

  1. Three major nucleolar proteins migrate from nucleolus to nucleoplasm and cytoplasm in root tip cells of Vicia faba L. exposed to aluminum.

    Science.gov (United States)

    Qin, Rong; Zhang, Huaning; Li, Shaoshan; Jiang, Wusheng; Liu, Donghua

    2014-09-01

    Results from our previous investigation indicated that Al could affect the nucleolus and induce extrusion of silver-staining nucleolar particles containing argyrophilic proteins from the nucleolus into the cytoplasm in root tip cells of Vicia faba L. So far, the nucleolar proteins involved have not been identified. It is well known that nucleophosmin (B23), nucleolin (C23), and fibrillarin are three major and multifunctional nucleolar proteins. Therefore, effects of Al on B23, C23, and fibrillarin in root tip cells of V. faba exposed to 100 μM Al for 48 h were observed and analyzed using indirect immunofluorescence microscopy and Western blotting. The results from this work demonstrated that after 100 μM of Al treatment for 48 h, B23 and C23 migrated from the nucleolus to the cytoplasm and fibrillarin from the nucleolus to the nucleoplasm. In some cells, fibrillarin was present only in the cytoplasm. Western blotting data revealed higher expression of the three major nucleolar proteins in Al-treated roots compared with the control and that the B23 content increased markedly. These findings confirmed our previous observations.

  2. Stressing on the nucleolus in cardiovascular disease.

    Science.gov (United States)

    Hariharan, Nirmala; Sussman, Mark A

    2014-06-01

    The nucleolus is a multifunctional organelle with multiple roles involving cell proliferation, growth, survival, ribosome biogenesis and stress response signaling. Alteration of nucleolar morphology and architecture signifies an early response to increased cellular stress. This review briefly summarizes nucleolar response to cardiac stress signals and details the role played by nucleolar proteins in cardiovascular pathophysiology. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.

  3. Effects of Lead on the Morphology and Structure of the Nucleolus in the Root Tip Meristematic Cells of Allium cepa L.

    OpenAIRE

    Ze Jiang; Huaning Zhang; Rong Qin; Jinhua Zou; Junran Wang; Qiuyue Shi; Wusheng Jiang; Donghua Liu

    2014-01-01

    To study the toxic mechanisms of lead (Pb) in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1–1...

  4. Abnormal integrity of the nucleolus associated with cell cycle arrest owing to the temperature-sensitive ubiquitin-activating enzyme E1.

    Science.gov (United States)

    Sudha, T; Tsuji, H; Sameshima, M; Matsuda, Y; Kaneda, S; Nagai, Y; Yamao, F; Seno, T

    1995-03-01

    A mouse cell mutant, ts85, containing the temperature-sensitive ubiquitin-activating enzyme was arrested in G2 phase at the non-permissive temperature. In the arrested cells, azure C, a nucleolus-specific stain, revealed a U-shaped or ring-shaped arrangement of nucleolar lobes with an unstained region in the center. Silver staining of the nucleolar organizer region (NOR) and fluorescence in situ hybridization (FISH) with rDNA both gave signals in azure C-positive regions. Electron microscopic examination revealed a cloud of unidentified electron-dense particles (diameter approximately 70 nm) in the azure C-negative center space. When the arrested cells were released into M-phase, we observed the association of NOR-bearing chromosomes with a pulverization-like abnormality. FISH with rDNA and NOR silver staining demonstrated that the pulverization-like abnormality was restricted to NORs. The frequent occurrence of persistent nucleolar material in prophase and prometaphase of the stressed cells after release indicated a delayed dissociation of the nucleolus that brought about the abnormal chromosomes in M-phase. ts85 cells transfected with the mouse E1 cDNA recovered growth at the non-permissive temperature and no longer showed abnormal nucleolar morphology. It seems that the ubiquitin system plays a role in the dissolution of the nucleolus, possibly involving the NOR-bearing chromosomes.

  5. Viruses and the nucleolus: the fatal attraction.

    Science.gov (United States)

    Salvetti, Anna; Greco, Anna

    2014-06-01

    Viruses are small obligatory parasites and as a consequence, they have developed sophisticated strategies to exploit the host cell's functions to create an environment that favors their own replication. A common feature of most - if not all - families of human and non-human viruses concerns their interaction with the nucleolus. The nucleolus is a multifunctional nuclear domain, which, in addition to its well-known role in ribosome biogenesis, plays several crucial other functions. Viral infection induces important nucleolar alterations. Indeed, during viral infection numerous viral components localize in nucleoli, while various host nucleolar proteins are redistributed in other cell compartments or are modified, and non-nucleolar cellular proteins reach the nucleolus. This review highlights the interactions reported between the nucleolus and some human or animal viral families able to establish a latent or productive infection, selected on the basis of their known interactions with the nucleolus and the nucleolar activities, and their links with virus replication and/or pathogenesis. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.

  6. [Advances in the study of the nucleolus].

    Science.gov (United States)

    Feng, Jin-Mei; Sun, Jun; Wen, Jian-Fan

    2012-12-01

    As the most prominent sub-nuclear compartment in the interphase nucleus and the site of ribosome biogenesis, the nucleolus synthesizes and processes rRNA and also assembles ribosomal subunits. Though several lines of research in recent years have indicated that the nucleolus might have additional functions-such as the assembling of signal recognition particles, the processing of mRNA, tRNA and telomerase activities, and regulating the cell cycle-proteomic analyses of the nucleolus in three representative eukaryotic species has shown that a plethora of proteins either have no association with ribosome biogenesis or are of presently unknown function. This phenomenon further indicates that the composition and function of the nucleolus is far more complicated than previously thought. Meanwhile, the available nucleolar proteome databases has provided new approaches and led to remarkable progress in understanding the nucleolus. Here, we have summarized recent advances in the study of the nucleolus, including new discoveries of its structure, function, genomics/proteomics as well as its origin and evolution. Moreover, we highlight several of the important unresolved issues in this field.

  7. [The nucleolus of the cell is the site of iron accumulation in the substantia nigra neurons of the human brain].

    Science.gov (United States)

    Sukhorukova, Ye G; Grigoriev, I P; Kolos, Ye A; Korzhenevskiy, D E

    2012-01-01

    Distribution of iron in the substantia nigra of the human brain (10 men and women aged 27-78 years) was studied using Perls' histochemical method. Iron ions were demonstrated in the nigral neuropil and melanin-containing neurons. For the first time the nuclei of some neurons were found to contain iron accumulations. The intranuclear iron inclusions correspond to the nucleolus according to their sharp outline and sizes. Detection of iron in the neuronal nucleolus may contribute to the understanding of mechanisms of iron neurotoxicity for nigral dopaminergic neurons.

  8. note: The least square nucleolus is a general nucleolus

    OpenAIRE

    Elisenda Molina; Juan Tejada

    2000-01-01

    This short note proves that the least square nucleolus (Ruiz et al. (1996)) and the lexicographical solution (Sakawa and Nishizaki (1994)) select the same imputation in each game with nonempty imputation set. As a consequence the least square nucleolus is a general nucleolus (Maschler et al. (1992)).

  9. The nucleolus gets the silent treatment.

    Science.gov (United States)

    Feinberg, Andrew P

    2014-12-01

    In this issue of Cell Stem Cell, Savić et al. (2014) and Kim et al. (2014) provide insight into how global heterochromatin condensation and LIN28 sequestration in embryonic stem cells are independent mechanisms regulating pluripotency in the oft-overlooked nucleolus.

  10. Configuration of nucleolarDNA in situ in nucleolus ofAllium cepa cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The location and configuration of nucleolar DNA have not beendetermined for a long time. In this paper, we have observed the nucleolar ultrastructure and the character of nucleolar DNA in Allium 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 DNA in situ. Our results indicated that the nucleolar DNA in Allium 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.

  11. Changes in biomolecular profile in a single nucleolus during cell fixation.

    Science.gov (United States)

    Kuzmin, Andrey N; Pliss, Artem; Prasad, Paras N

    2014-11-01

    Fixation of biological sample is an essential technique applied in order to "freeze" in time the intracellular molecular content. However, fixation induces changes of the cellular molecular structure, which mask physiological distribution of biomolecules and bias interpretation of results. Accurate, sensitive, and comprehensive characterization of changes in biomolecular composition, occurring during fixation, is crucial for proper analysis of experimental data. Here we apply biomolecular component analysis for Raman spectra measured in the same nucleoli of HeLa cells before and after fixation by either formaldehyde solution or by chilled ethanol. It is found that fixation in formaldehyde does not strongly affect the Raman spectra of nucleolar biomolecular components, but may significantly decrease the nucleolar RNA concentration. At the same time, ethanol fixation leads to a proportional increase (up to 40%) in concentrations of nucleolar proteins and RNA, most likely due to cell shrinkage occurring in the presence of coagulant fixative. Ethanol fixation also triggers changes in composition of nucleolar proteome, as indicated by an overall reduction of the α-helical structure of proteins and increase in the concentration of proteins containing the β-sheet conformation. We conclude that cross-linking fixation is a more appropriate protocol for mapping of proteins in situ. At the same time, ethanol fixation is preferential for studies of RNA-containing macromolecules. We supplemented our quantitative Raman spectroscopic measurements with mapping of the protein and lipid macromolecular groups in live and fixed cells using coherent anti-Stokes Raman scattering nonlinear optical imaging.

  12. Initial genomics of the human nucleolus.

    Directory of Open Access Journals (Sweden)

    Attila Németh

    2010-03-01

    Full Text Available We report for the first time the genomics of a nuclear compartment of the eukaryotic cell. 454 sequencing and microarray analysis revealed the pattern of nucleolus-associated chromatin domains (NADs in the linear human genome and identified different gene families and certain satellite repeats as the major building blocks of NADs, which constitute about 4% of the genome. Bioinformatic evaluation showed that NAD-localized genes take part in specific biological processes, like the response to other organisms, odor perception, and tissue development. 3D FISH and immunofluorescence experiments illustrated the spatial distribution of NAD-specific chromatin within interphase nuclei and its alteration upon transcriptional changes. Altogether, our findings describe the nature of DNA sequences associated with the human nucleolus and provide insights into the function of the nucleolus in genome organization and establishment of nuclear architecture.

  13. Developmental regulation of nucleolus size during Drosophila eye differentiation.

    Science.gov (United States)

    Baker, Nicholas E

    2013-01-01

    When cell cycle withdrawal accompanies terminal differentiation, biosynthesis and cellular growth are likely to change also. In this study, nucleolus size was monitored during cell fate specification in the Drosophila eye imaginal disc using fibrillarin antibody labeling. Nucleolus size is an indicator of ribosome biogenesis and can correlate with cellular growth rate. Nucleolar size was reduced significantly during cell fate specification and differentiation, predominantly as eye disc cells entered a cell cycle arrest that preceded cell fate specification. This reduction in nucleolus size required Dpp and Hh signaling. A transient enlargement of the nucleolus accompanied cell division in the Second Mitotic Wave. Nucleoli continued to diminish in postmitotic cells following fate specification. These results suggest that cellular growth is regulated early in the transition from proliferating progenitor cells to terminal cell fate specification, contemporary with regulation of the cell cycle, and requiring the same extracellular signals.

  14. Targeting the nucleolus for cancer intervention.

    Science.gov (United States)

    Quin, Jaclyn E; Devlin, Jennifer R; Cameron, Donald; Hannan, Kate M; Pearson, Richard B; Hannan, Ross D

    2014-06-01

    The contribution of the nucleolus to cancer is well established with respect to its traditional role in facilitating ribosome biogenesis and proliferative capacity. More contemporary studies however, infer that nucleoli contribute a much broader role in malignant transformation. Specifically, extra-ribosomal functions of the nucleolus position it as a central integrator of cellular proliferation and stress signaling, and are emerging as important mechanisms for modulating how oncogenes and tumor suppressors operate in normal and malignant cells. The dependence of certain tumor cells to co-opt nucleolar processes to maintain their cancer phenotypes has now clearly been demonstrated by the application of small molecule inhibitors of RNA Polymerase I to block ribosomal DNA transcription and disrupt nucleolar function (Bywater et al., 2012 [1]). These drugs, which selectively kill tumor cells in vivo while sparing normal cells, have now progressed to clinical trials. It is likely that we have only just begun to scratch the surface of the potential of the nucleolus as a new target for cancer therapy, with "suppression of nucleolar stress" representing an emerging "hallmark" of cancer. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.

  15. Directed proteomic analysis of the human nucleolus

    DEFF Research Database (Denmark)

    Andersen, Jens S; Lyon, Carol E; Fox, Archa H

    2002-01-01

    BACKGROUND: The nucleolus is a subnuclear organelle containing the ribosomal RNA gene clusters and ribosome biogenesis factors. Recent studies suggest it may also have roles in RNA transport, RNA modification, and cell cycle regulation. Despite over 150 years of research into nucleoli, many aspec...

  16. The Nucleolus of Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Li-Wei Lee

    2012-01-01

    Full Text Available Nucleolar size and appearance correlate with ribosome biogenesis and cellular activity. The mechanisms underlying changes in nucleolar appearance and regulation of nucleolar size that occur during differentiation and cell cycle progression are not well understood. Caenorhabditis elegans provides a good model for studying these processes because of its small size and transparent body, well-characterized cell types and lineages, and because its cells display various sizes of nucleoli. This paper details the advantages of using C. elegans to investigate features of the nucleolus during the organism's development by following dynamic changes in fibrillarin (FIB-1 in the cells of early embryos and aged worms. This paper also illustrates the involvement of the ncl-1 gene and other possible candidate genes in nucleolar-size control. Lastly, we summarize the ribosomal proteins involved in life span and innate immunity, and those homologous genes that correspond to human disorders of ribosomopathy.

  17. Proteomic Analysis of Bovine Nucleolus

    Institute of Scientific and Technical Information of China (English)

    Amrutlal K.Patel; Doug Olson; Suresh K. Tikoo

    2010-01-01

    Nucleolus is the most prominent subnuclear structure, which performs a wide variety of functions in the eu-karyotic cellular processes. In order to understand the structural and functional role of the nucleoli in bovine cells,we analyzed the proteomie composition of the bovine nueleoli. The nucleoli were isolated from Madin Darby bo-vine kidney cells and subjected to proteomie analysis by LC-MS/MS after fractionation by SDS-PAGE and strongcation exchange chromatography. Analysis of the data using the Mascot database search and the GPM databasesearch identified 311 proteins in the bovine nucleoli, which contained 22 proteins previously not identified in theproteomic analysis of human nucleoli. Analysis of the identified proteins using the GoMiner software suggestedthat the bovine nueleoli contained proteins involved in ribosomal biogenesis, cell cycle control, transcriptional,translational and post-translational regulation, transport, and structural organization.

  18. Low molecular weight fluorescent probes with good photostability for imaging RNA-rich nucleolus and RNA in cytoplasm in living cells.

    Science.gov (United States)

    Song, Guofen; Sun, Yuming; Liu, Yong; Wang, Xiankun; Chen, Meiling; Miao, Fang; Zhang, Weijia; Yu, Xiaoqiang; Jin, Jianling

    2014-02-01

    We have synthesized two low molecular weight organic molecules, PY and IN successfully, which selectively stain nucleolus and cytoplasm of living cells in 30 min, with a much lower uptake in the nucleus. Nucleic acids electrophoresis and digest test of ribonuclease indicate their markedly higher affinity for RNA, especially PY. Moreover their RNA localization in cells is further supported by digest test of ribonuclease, namely, the nucleolar fluorescence signal is distinctly lost upon treatment with RNase. And, the fact that live cells stained by PY and IN still possess physiological function can be confirmed: 1) MTT assay demonstrates that the mitochondria of cells stained remains its electron mediating ability, 2) Double assay of PY/IN and propidium iodide as well as trypan blue testing show that the membrane of cells stained still is intact. Importantly, compared with the only commercial RNA probe, SYTO RNA-Select, PY and IN exhibit much better photostability when continuously illuminated with 488 nm laser and mercury lamp. These results prove that PY and IN are very attractive staining reagents for visualizing RNA in living cells.

  19. Effects of Lead on the Morphology and Structure of the Nucleolus in the Root Tip Meristematic Cells of Allium cepa L.

    Directory of Open Access Journals (Sweden)

    Ze Jiang

    2014-07-01

    Full Text Available To study the toxic mechanisms of lead (Pb in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1–10 μM there were persistent nucleoli in some cells during mitosis, and at high concentration (100 μM many of the nucleolar organizing regions were localized on sticky chromosomes in metaphase and anaphase cells. Pb induced the release of particles containing argyrophilic proteins to be released from the nucleus into the cytoplasm. These proteins contained nucleophosmin and nucleolin. Pb also caused the extrusion of fibrillarin from the nucleus into the cytoplasm. Western blotting demonstrated the increased expression of these three major nucleolar proteins under Pb stress.

  20. Effects of lead on the morphology and structure of the nucleolus in the root tip meristematic cells of Allium cepa L.

    Science.gov (United States)

    Jiang, Ze; Zhang, Huaning; Qin, Rong; Zou, Jinhua; Wang, Junran; Shi, Qiuyue; Jiang, Wusheng; Liu, Donghua

    2014-07-31

    To study the toxic mechanisms of lead (Pb) in plants, the effects of Pb on the morphology and structure of the nucleolus in root tip meristematic cells of Allium cepa var. agrogarum L. were investigated. Fluorescence labeling, silver-stained indirect immunofluorescent microscopy and western blotting were used. Fluorescence labeling showed that Pb ions were localized in the meristematic cells and the uptake and accumulation of Pb increased with treatment time. At low concentrations of Pb (1-10 μM) there were persistent nucleoli in some cells during mitosis, and at high concentration (100 μM) many of the nucleolar organizing regions were localized on sticky chromosomes in metaphase and anaphase cells. Pb induced the release of particles containing argyrophilic proteins to be released from the nucleus into the cytoplasm. These proteins contained nucleophosmin and nucleolin. Pb also caused the extrusion of fibrillarin from the nucleus into the cytoplasm. Western blotting demonstrated the increased expression of these three major nucleolar proteins under Pb stress.

  1. Identification of Nucleolus-Associated Chromatin Domains Reveals a Role for the Nucleolus in 3D Organization of the A. thaliana Genome.

    Science.gov (United States)

    Pontvianne, Frédéric; Carpentier, Marie-Christine; Durut, Nathalie; Pavlištová, Veronika; Jaške, Karin; Schořová, Šárka; Parrinello, Hugues; Rohmer, Marine; Pikaard, Craig S; Fojtová, Miloslava; Fajkus, Jiří; Sáez-Vásquez, Julio

    2016-08-01

    The nucleolus is the site of rRNA gene transcription, rRNA processing, and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli using fluorescence-activated cell sorting (FACS) and identified nucleolus-associated chromatin domains (NADs) by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein NUCLEOLIN 1 (NUC1). NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs), sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include active rRNA genes and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased, and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance.

  2. Bioinformatic analysis of the nucleolus

    DEFF Research Database (Denmark)

    Leung, Anthony K L; Andersen, Jens S; Mann, Matthias;

    2003-01-01

    The nucleolus is a plurifunctional, nuclear organelle, which is responsible for ribosome biogenesis and many other functions in eukaryotes, including RNA processing, viral replication and tumour suppression. Our knowledge of the human nucleolar proteome has been expanded dramatically by the two r...

  3. The nucleolus and transcription of ribosomal genes.

    Science.gov (United States)

    Raska, Ivan; Koberna, Karel; Malínský, Jan; Fidlerová, Helena; Masata, Martin

    2004-10-01

    Ribosome biogenesis is a highly dynamic, steady-state nucleolar process that involves synthesis and maturation of rRNA, its transient interactions with non-ribosomal proteins and RNPs and assembly with ribosomal proteins. In the few years of the 21st century, an exciting progress in the molecular understanding of rRNA and ribosome biogenesis has taken place. In this review, we discuss the recent results on the regulation of rRNA synthesis in relation to the functional organization of the nucleolus, and put an emphasis on the situation encountered in mammalian somatic cells.

  4. Functional ultrastructure of the plant nucleolus.

    Science.gov (United States)

    Stępiński, Dariusz

    2014-11-01

    Nucleoli are nuclear domains present in almost all eukaryotic cells. They not only specialize in the production of ribosomal subunits but also play roles in many fundamental cellular activities. Concerning ribosome biosynthesis, particular stages of this process, i.e., ribosomal DNA transcription, primary RNA transcript processing, and ribosome assembly proceed in precisely defined nucleolar subdomains. Although eukaryotic nucleoli are conservative in respect of their main function, clear morphological differences between these structures can be noticed between individual kingdoms. In most cases, a plant nucleolus shows well-ordered structure in which four main ultrastructural components can be distinguished: fibrillar centers, dense fibrillar component, granular component, and nucleolar vacuoles. Nucleolar chromatin is an additional crucial structural component of this organelle. Nucleolonema, although it is not always an unequivocally distinguished nucleolar domain, has often been described as a well-grounded morphological element, especially of plant nucleoli. The ratios and morphology of particular subcompartments of a nucleolus can change depending on its metabolic activity which in turn is correlated with the physiological state of a cell, cell type, cell cycle phase, as well as with environmental influence. Precise attribution of functions to particular nucleolar subregions in the process of ribosome biosynthesis is now possible using various approaches. The presented description of plant nucleolar morphology summarizes previous knowledge regarding the function of nucleoli as well as of their particular subdomains not only in the course of ribosome biosynthesis.

  5. Regulation of nucleolus assembly by non-coding RNA polymerase II transcripts.

    Science.gov (United States)

    Caudron-Herger, Maïwen; Pankert, Teresa; Rippe, Karsten

    2016-05-01

    The nucleolus is a nuclear subcompartment for tightly regulated rRNA production and ribosome subunit biogenesis. It also acts as a cellular stress sensor and can release enriched factors in response to cellular stimuli. Accordingly, the content and structure of the nucleolus change dynamically, which is particularly evident during cell cycle progression: the nucleolus completely disassembles during mitosis and reassembles in interphase. Although the mechanisms that drive nucleolar (re)organization have been the subject of a number of studies, they are only partly understood. Recently, we identified Alu element-containing RNA polymerase II transcripts (aluRNAs) as important for nucleolar structure and rRNA synthesis. Integrating these findings with studies on the liquid droplet-like nature of the nucleolus leads us to propose a model on how RNA polymerase II transcripts could regulate the assembly of the nucleolus in response to external stimuli and during cell cycle progression.

  6. Principles of protein targeting to the nucleolus.

    Science.gov (United States)

    Martin, Robert M; Ter-Avetisyan, Gohar; Herce, Henry D; Ludwig, Anne K; Lättig-Tünnemann, Gisela; Cardoso, M Cristina

    2015-01-01

    The nucleolus is the hallmark of nuclear compartmentalization and has been shown to exert multiple roles in cellular metabolism besides its main function as the place of rRNA synthesis and assembly of ribosomes. Nucleolar proteins dynamically localize and accumulate in this nuclear compartment relative to the surrounding nucleoplasm. In this study, we have assessed the molecular requirements that are necessary and sufficient for the localization and accumulation of peptides and proteins inside the nucleoli of living cells. The data showed that positively charged peptide entities composed of arginines alone and with an isoelectric point at and above 12.6 are necessary and sufficient for mediating significant nucleolar accumulation. A threshold of 6 arginines is necessary for peptides to accumulate in nucleoli, but already 4 arginines are sufficient when fused within 15 amino acid residues of a nuclear localization signal of a protein. Using a pH sensitive dye, we found that the nucleolar compartment is particularly acidic when compared to the surrounding nucleoplasm and, hence, provides the ideal electrochemical environment to bind poly-arginine containing proteins. In fact, we found that oligo-arginine peptides and GFP fusions bind RNA in vitro. Consistent with RNA being the main binding partner for arginines in the nucleolus, we found that the same principles apply to cells from insects to man, indicating that this mechanism is highly conserved throughout evolution.

  7. [PIWI protein as a nucleolus visitor in Drosophila melanogaster].

    Science.gov (United States)

    Mikhaleva, E A; Iakushev, E Iu; Stoliarenko, A D; Klenov, M S; Pozovskiĭ, Ia M; Gvozdev, V A

    2015-01-01

    The evolutionarily conserved nuclear Piwi protein of Drosophila melanogaster is a representative of the Argonaute small RNA binding protein family. Guided by small piRNAs, Piwi functions in transposon silencing in somatic and germ cells of the gonad. We found that in ovarian somatic and germ cells, as well as in the established ovarian somatic cell line, Piwi is concentrated predominantly in the nucleolus--the main nuclear compartment, participating not only in rRNA synthesis, but also in various cell stress responses. We demonstrated the colocalization of Piwi with nucleolar marker proteins--fibrillarin and Nopp140. A mutation preventing Piwi transport to the nucleus and disturbing transposon silencing (piwi(Nt)) leads to 6-8-fold upregulation of rRNA genes expression, as evaluated by the level of transcripts of transposon insertions in 28S rRNA genes. RNase treatment of live cultured ovarian somatic cells depletes Piwi from the nucleolus. The same effect is observed upon inhibiting RNA polymerase I which transcribes rRNA, but not RNA polymerase II. In contrast, upon heat shock Piwi is concentrated in the nucleolus and is depleted from the nucleoplasm. These results implicate Piwi in RNA polymerase activity modulation and stress response in the nucleolus. We discuss possible noncanonical Piwi functions along with its canonical role in transposon silencing by piRNAs.

  8. Recent studies implicate the nucleolus as the major site of nuclear translation.

    Science.gov (United States)

    McLeod, Tina; Abdullahi, Akilu; Li, Min; Brogna, Saverio

    2014-08-01

    The nucleolus is the most prominent morphological feature within the nucleus of eukaryotic cells and is best known for its role in ribosome biogenesis. It forms around highly transcribed ribosomal RNA gene repeats which yield precursor rRNAs that are co-transcriptionally processed, folded and, while still within the nucleolus, associate with most of the ribosomal proteins. The nucleolus is therefore often thought of as a factory for making ribosomal subunits, which are exported as inactive precursors to the cytoplasm where late maturation makes them capable of mRNA binding and translation initiation. However, recent studies have shown substantial evidence for the presence of functional, translation competent ribosomal subunits within the nucleus, particularly in the nucleolus. These observations raise the intriguing possibility that the nucleolus, as well as being a ribosome factory, is also an important nuclear protein-synthesis plant.

  9. ARF tumor suppression in the nucleolus.

    Science.gov (United States)

    Maggi, Leonard B; Winkeler, Crystal L; Miceli, Alexander P; Apicelli, Anthony J; Brady, Suzanne N; Kuchenreuther, Michael J; Weber, Jason D

    2014-06-01

    Since its discovery close to twenty years ago, the ARF tumor suppressor has played a pivotal role in the field of cancer biology. Elucidating ARF's basal physiological function in the cell has been the focal interest of numerous laboratories throughout the world for many years. Our current understanding of ARF is constantly evolving to include novel frameworks for conceptualizing the regulation of this critical tumor suppressor. As a result of this complexity, there is great need to broaden our understanding of the intricacies governing the biology of the ARF tumor suppressor. The ARF tumor suppressor is a key sensor of signals that instruct a cell to grow and proliferate and is appropriately localized in nucleoli to limit these processes. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.

  10. A Nucleolus for Stochastic Cooperative Games

    NARCIS (Netherlands)

    Suijs, J.P.M.

    1996-01-01

    This paper extends the definition of the nucleolus to stochastic cooperative games, that is, to cooperative games with random payoffs to the coalitions. It is shown that the nucleolus is nonempty and that it belongs to the core whenever the core is nonempty. Furthermore, it is shown for a particular

  11. Sequential recovery of macromolecular components of the nucleolus.

    Science.gov (United States)

    Bai, Baoyan; Laiho, Marikki

    2015-01-01

    The nucleolus is involved in a number of cellular processes of importance to cell physiology and pathology, including cell stress responses and malignancies. Studies of macromolecular composition of the nucleolus depend critically on the efficient extraction and accurate quantification of all macromolecular components (e.g., DNA, RNA, and protein). We have developed a TRIzol-based method that efficiently and simultaneously isolates these three macromolecular constituents from the same sample of purified nucleoli. The recovered and solubilized protein can be accurately quantified by the bicinchoninic acid assay and assessed by polyacrylamide gel electrophoresis or by mass spectrometry. We have successfully applied this approach to extract and quantify the responses of all three macromolecular components in nucleoli after drug treatments of HeLa cells, and conducted RNA-Seq analysis of the nucleolar RNA.

  12. Apoptosis and expression of argyrophilic nucleolus organizer regions in epithelial neoplasms of the larynx

    Directory of Open Access Journals (Sweden)

    Christiana Vargas Ribeiro

    2015-04-01

    Full Text Available INTRODUCTION: Occurrence of apoptosis and expression of proliferative markers are powerful tools to establish a prognosis in the follow-up of cancer.OBJECTIVE: To evaluate the growth fraction in papillomas and laryngeal squamous cell carcinomas with three degrees of differentiation through apoptosis and the expression of nucleolus organizer regions.METHODS: Retrospective study from which paraffin material was submitted to microtomy and hematoxylin-eosin and silver staining. Stained slides were used to quantify the apoptotic index and the number of nucleolus organizer regions by morphometry.RESULTS: Apoptosis was significantly more frequent in well differentiated carcinomas and in papillomas, and a higher growth fraction of expressed nucleolus organizer regions and cells that expressed a greater than average number of nucleolus organizer regions were more frequently noted in undifferentiated carcinomas.CONCLUSIONS: Thus, it was possible to verify that a high apoptotic index was associated with a lower chance of tumor differentiation in carcinomas, while a greater number of total nucleolus organizer regions, cells expressing nucleolus organizer regions above average and a higher growth fraction were associated with greater likelihood of abnormal cell proliferation and increased tumor differentiation.

  13. Human nucleolus organizers on nonhomologous chromosomes can share the same ribosomal gene variants.

    OpenAIRE

    Krystal, M; D'Eustachio, P; Ruddle, F H; Arnheim, N

    1981-01-01

    The distributions of three human ribosomal gene polymorphisms among individual chromosomes containing nucleolus organizers were analyzed by using mouse--human hybrid cells. Different nucleolus organizers can contain the same variant, suggesting the occurrence of genetic exchanges among ribosomal gene clusters on nonhomologous chromosomes. Such exchanges appear to occur less frequently in mice. This difference is discussed in terms of the nucleolar organization and chromosomal location of ribo...

  14. The nucleolus in Entamoeba histolytica and Entamoeba invadens is located at the nuclear periphery.

    Science.gov (United States)

    Jhingan, Gagan Deep; Panigrahi, Sunil K; Bhattacharya, Alok; Bhattacharya, Sudha

    2009-09-01

    The ribosomal RNA genes in the human parasite Entamoeba histolytica and its reptilian counterpart Entamoeba invadens are located on extrachromosomal circles. The expression of rRNA genes generally takes place in a specialized nuclear compartment-the nucleolus. In Entamoeba species the nuclear space that may be called the nucleolus has yet to be defined. Previous studies showed that the rDNA circles are located at the nuclear periphery. Here we have raised antibodies against the E. histolytica homologue of fibrillarin, a highly conserved protein known to be a marker for nucleolus. These antibodies cross-reacted preferentially with the nuclear periphery, forming a peripheral ring. There was complete colocalization of fibrillarin with the signal obtained by antibodies against E. histolytica RNA polymerase I (but not polymerase II and III), strongly suggesting that the nucleolus in E. histolytica is indeed located at the nuclear periphery. The dynamic nature of the nucleolus was evident when cells were subjected to a variety of growth stresses. Although the peripheral nucleolar structure was retained, stress was accompanied by significant cytoplasmic localization of RNA polymerase I, and to some extent fibrillarin. The nucleolus in E. invadens was also located at the nuclear periphery. When these cells were induced to encyst the nucleolar ring structure was lost, giving way to small, fragmented foci. This study gives the first clear insight into nucleolar structure in Entamoeba.

  15. Distribution of DNA and localization of rRNA transcription in G2 phase nucleolus of Physarum polycephalum

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using electron microscopy, NAMA-Ur DNA selective staining and BrUTP incorporation, the nucleo lus ultrastructure, the distribution of DNA and the rRNA transcription sites in nucleolus of G2 phase Physarum poly cephalum were studied. The nucleolus was found to be different in structure from that of other plant cells. Fibrillar cen tern (FCs) were present in a large amount all over the nucleolus. DNA was distributed both in dense fibrillar components (DFC) and in FC. The DNA in the nucleolus was less condensed than that of the chromosome territory. These changes suggested that the transcription was active within the nucleolus. BrUTP incorporation localized the rRNA transcription in DFC and at the interface of FC and DFC, suggesting that the DNA in FC is in a storage form and only the rDNA in DFC is transcribed.

  16. Identification of Nucleolus-Associated Chromatin Domains Reveals a Role for the Nucleolus in 3D Organization of the A. thaliana Genome

    Directory of Open Access Journals (Sweden)

    Frédéric Pontvianne

    2016-08-01

    Full Text Available The nucleolus is the site of rRNA gene transcription, rRNA processing, and ribosome biogenesis. However, the nucleolus also plays additional roles in the cell. We isolated nucleoli using fluorescence-activated cell sorting (FACS and identified nucleolus-associated chromatin domains (NADs by deep sequencing, comparing wild-type plants and null mutants for the nucleolar protein NUCLEOLIN 1 (NUC1. NADs are primarily genomic regions with heterochromatic signatures and include transposable elements (TEs, sub-telomeric regions, and mostly inactive protein-coding genes. However, NADs also include active rRNA genes and the entire short arm of chromosome 4 adjacent to them. In nuc1 null mutants, which alter rRNA gene expression and overall nucleolar structure, NADs are altered, telomere association with the nucleolus is decreased, and telomeres become shorter. Collectively, our studies reveal roles for NUC1 and the nucleolus in the spatial organization of chromosomes as well as telomere maintenance.

  17. The nucleolus: a raft adrift in the nuclear sea or the keystone in nuclear structure?

    Science.gov (United States)

    O'Sullivan, Justin M; Pai, Dave A; Cridge, Andrew G; Engelke, David R; Ganley, Austen R D

    2013-06-01

    The nucleolus is a prominent nuclear structure that is the site of ribosomal RNA (rRNA) transcription, and hence ribosome biogenesis. Cellular demand for ribosomes, and hence rRNA, is tightly linked to cell growth and the rRNA makes up the majority of all the RNA within a cell. To fulfill the cellular demand for rRNA, the ribosomal RNA (rDNA) genes are amplified to high copy number and transcribed at very high rates. As such, understanding the rDNA has profound consequences for our comprehension of genome and transcriptional organization in cells. In this review, we address the question of whether the nucleolus is a raft adrift the sea of nuclear DNA, or actively contributes to genome organization. We present evidence supporting the idea that the nucleolus, and the rDNA contained therein, play more roles in the biology of the cell than simply ribosome biogenesis. We propose that the nucleolus and the rDNA are central factors in the spatial organization of the genome, and that rapid alterations in nucleolar structure in response to changing conditions manifest themselves in altered genomic structures that have functional consequences. Finally, we discuss some predictions that result from the nucleolus having a central role in nuclear organization.

  18. The maternal nucleolus plays a key role in centromere satellite maintenance during the oocyte to embryo transition.

    Science.gov (United States)

    Fulka, Helena; Langerova, Alena

    2014-04-01

    The oocyte (maternal) nucleolus is essential for early embryonic development and embryos originating from enucleolated oocytes arrest at the 2-cell stage. The reason for this is unclear. Surprisingly, RNA polymerase I activity in nucleolus-less mouse embryos, as manifested by pre-rRNA synthesis, and pre-rRNA processing are not affected, indicating an unusual role of the nucleolus. We report here that the maternal nucleolus is indispensable for the regulation of major and minor satellite repeats soon after fertilisation. During the first embryonic cell cycle, absence of the nucleolus causes a significant reduction in major and minor satellite DNA by 12% and 18%, respectively. The expression of satellite transcripts is also affected, being reduced by more than half. Moreover, extensive chromosome bridging of the major and minor satellite sequences was observed during the first mitosis. Finally, we show that the absence of the maternal nucleolus alters S-phase dynamics and causes abnormal deposition of the H3.3 histone chaperone DAXX in pronuclei of nucleolus-less zygotes.

  19. Bankruptcy and the Per Capita Nucleolus

    NARCIS (Netherlands)

    Huijink, S.; Borm, P.E.M.; Reijnierse, J.H.; Kleppe, J.

    2013-01-01

    Abstract: This article characterizes the per capita nucleolus for bankruptcy games as a bankruptcy rule. This rule, called the cligths rule, is based on the wellknown constrained equal awards principle. The essential feature of the rule however is that, for each bankruptcy problem, it takes into acc

  20. Involvement of the plant nucleolus in virus and viroid infections: parallels with animal pathosystems.

    Science.gov (United States)

    Taliansky, M E; Brown, J W S; Rajamäki, M L; Valkonen, J P T; Kalinina, N O

    2010-01-01

    The nucleolus is a dynamic subnuclear body with roles in ribosome subunit biogenesis, mediation of cell-stress responses, and regulation of cell growth. An increasing number of reports reveal that similar to the proteins of animal viruses, many plant virus proteins localize in the nucleolus to divert host nucleolar proteins from their natural functions in order to exert novel role(s) in the virus infection cycle. This chapter will highlight studies showing how plant viruses recruit nucleolar functions to facilitate virus translation and replication, virus movement and assembly of virus-specific ribonucleoprotein (RNP) particles, and to counteract plant host defense responses. Plant viruses also provide a valuable tool to gain new insights into novel nucleolar functions and processes. Investigating the interactions between plant viruses and the nucleolus will facilitate the design of novel strategies to control plant virus infections.

  1. The actin family protein ARP6 contributes to the structure and the function of the nucleolus

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Hiroshi [Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoka-ku, Sendai 981-8555 (Japan); Matsumori, Haruka [Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811 (Japan); Kalendova, Alzbeta; Hozak, Pavel [Department of Biology of the Cell Nucleus, Institute of Molecular Genetics of the Academy of Sciences of the Czech Republic, v.v.i., Vídeňská 1083, 142 20 Prague (Czech Republic); Goldberg, Ilya G. [Image Informatics and Computational Biology Unit, Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224 (United States); Nakao, Mitsuyoshi [Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811 (Japan); Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, Tokyo 102-0076 (Japan); Saitoh, Noriko [Department of Medical Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto 860-0811 (Japan); Harata, Masahiko, E-mail: mharata@biochem.tohoku.ac.jp [Laboratory of Molecular Biology, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori-Amamiyamachi 1-1, Aoka-ku, Sendai 981-8555 (Japan)

    2015-08-21

    The actin family members, consisting of actin and actin-related proteins (ARPs), are essential components of chromatin remodeling complexes. ARP6, one of the nuclear ARPs, is part of the Snf-2-related CREB-binding protein activator protein (SRCAP) chromatin remodeling complex, which promotes the deposition of the histone variant H2A.Z into the chromatin. In this study, we showed that ARP6 influences the structure and the function of the nucleolus. ARP6 is localized in the central region of the nucleolus, and its knockdown induced a morphological change in the nucleolus. We also found that in the presence of high concentrations of glucose ARP6 contributed to the maintenance of active ribosomal DNA (rDNA) transcription by placing H2A.Z into the chromatin. In contrast, under starvation, ARP6 was required for cell survival through the repression of rDNA transcription independently of H2A.Z. These findings reveal novel pleiotropic roles for the actin family in nuclear organization and metabolic homeostasis. - Highlights: • ARP6, an actin related protein, is important for nucleolar function and structure. • A population of ARP6 is localized in the center of nucleolus. • Depletion of ARP6 resulted in aberrant shape of the nucleolus. • ARP6 maintains the active rDNA transcription under high glucose. • ARP6 is required for the repression of rDNA transcription under starvation.

  2. Epigenetics and autoimmune diseases: the X chromosome-nucleolus nexus.

    Science.gov (United States)

    Brooks, Wesley H; Renaudineau, Yves

    2015-01-01

    Autoimmune diseases occur more often in females, suggesting a key role for the X chromosome. X chromosome inactivation, a major epigenetic feature in female cells that provides dosage compensation of X-linked genes to avoid overexpression, presents special vulnerabilities that can contribute to the disease process. Disruption of X inactivation can result in loss of dosage compensation with expression from previously sequestered genes, imbalance of gene products, and altered endogenous material out of normal epigenetic context. In addition, the human X has significant differences compared to other species and these differences can contribute to the frequency and intensity of the autoimmune disease in humans as well as the types of autoantigens encountered. Here a link is demonstrated between autoimmune diseases, such as systemic lupus erythematosus, and the X chromosome by discussing cases in which typically non-autoimmune disorders complicated with X chromosome abnormalities also present lupus-like symptoms. The discussion is then extended to the reported spatial and temporal associations of the inactive X chromosome with the nucleolus. When frequent episodes of cellular stress occur, the inactive X chromosome may be disrupted and inadvertently become involved in the nucleolar stress response. Development of autoantigens, many of which are at least transiently components of the nucleolus, is then described. Polyamines, which aid in nucleoprotein complex assembly in the nucleolus, increase further during cell stress, and appear to have an important role in the autoimmune disease process. Autoantigenic endogenous material can potentially be stabilized by polyamines. This presents a new paradigm for autoimmune diseases: that many are antigen-driven and the autoantigens originate from altered endogenous material due to episodes of cellular stress that disrupt epigenetic control. This suggests that epigenetics and the X chromosome are important aspects of autoimmune

  3. Interchanges in popcorn (Zea mays L. involving the nucleolus organizer chromosome

    Directory of Open Access Journals (Sweden)

    Maria Suely Pagliarini

    2006-01-01

    Full Text Available The analysis of microsporogenesis in endogamous plants of popcorn (S5 to S7 showed several and distinctinterchanges which involve the nucleolus organizer (chromosome 6. The detection of cells with interchanges was facilitatedby the presence of two nucleoli of different sizes in contrast to normal ones with a single big nucleolus. Interchange points donot always seem to be at the same place. Whereas in several situations the interchange point clearly involved more than twochromosome pairs, a simple terminal translocation seemed to occur in others. During diplotene, a cross-shaped configurationconnected with the nucleoli was observed in some meiocytes. Some heteromorphic bivalents were found during diakinesis,after which meiosis progressed normally to the end and gave rise to apparently normal tetrads with one normal nucleolus ineach microspore. Tests of pollen viability in fixed pollen grains showed 100% stainability in normal and in affected plants.This is the first report on chromosome interchanges in popcorn.

  4. Analysis of histone posttranslational modifications from nucleolus-associated chromatin by mass spectrometry.

    Science.gov (United States)

    Dillinger, Stefan; Garea, Ana Villar; Deutzmann, Rainer; Németh, Attila

    2014-01-01

    Chromatin is unevenly distributed within the eukaryote nucleus and it contributes to the formation of morphologically and functionally distinct substructures, called chromatin domains and nuclear bodies. Here we describe an approach to assess specific chromatin features, the histone posttranslational modifications (PTMs), of the largest nuclear sub-compartment, the nucleolus. In this chapter, methods for the isolation of nucleolus-associated chromatin from native or formaldehyde-fixed cells and the effect of experimental procedures on the outcome of mass spectrometry analysis of histone PTMs are compared.

  5. Curcumin homing to the nucleolus: mechanism for initiation of an apoptotic program.

    Science.gov (United States)

    Ghosh, Mistuni; Ryan, Robert O

    2014-11-01

    Curcumin is a plant-derived polyphenol that displays antitumor properties. Incubation of cultured SF-767 glioma cells with curcumin gave rise to intense intranuclear foci of curcumin fluorescence. In vitro studies revealed that nuclear homing by curcumin is not a result of DNA/chromatin binding. On the other hand, curcumin fluorescence colocalized with nucleophosmin, a nucleolus marker protein. To determine the temporal relationship between curcumin-induced apoptosis and nucleolar homing, confocal live cell imaging was performed. The data show that curcumin localization to the nucleolus occurs prior to cell surface exposure of phosphatidylserine. In studies of the mechanism of curcumin-induced apoptosis in SF-767 cells, its effect on the subcellular location of p14(ARF) was determined. Whereas p14(ARF) was confined to the nucleolus in untreated cells, 2 h following incubation with curcumin, it displayed a diffuse nuclear distribution. Given the role of nuclear p14(ARF) in binding the E3 ubiquitin ligase, mouse double minute 2 homolog (MDM2), the effect of curcumin treatment on cellular levels of the tumor suppressor protein, p53, was examined. Between 2 and 4 h following curcumin treatment, p53 levels increased with maximum levels reached by 8 h. Thus, curcumin homing to the nucleolus induces redistribution of p14(ARF) to the nucleoplasm where interaction with MDM2 leads to stabilization of p53, with subsequent initiation of apoptosis.

  6. Computing the nucleolus of weighted voting games

    CERN Document Server

    Elkind, Edith

    2008-01-01

    Weighted voting games (WVG) are coalitional games in which an agent's contribution to a coalition is given by his it weight, and a coalition wins if its total weight meets or exceeds a given quota. These games model decision-making in political bodies as well as collaboration and surplus division in multiagent domains. The computational complexity of various solution concepts for weighted voting games received a lot of attention in recent years. In particular, Elkind et al.(2007) studied the complexity of stability-related solution concepts in WVGs, namely, of the core, the least core, and the nucleolus. While they have completely characterized the algorithmic complexity of the core and the least core, for the nucleolus they have only provided an NP-hardness result. In this paper, we solve an open problem posed by Elkind et al. by showing that the nucleolus of WVGs, and, more generally, k-vector weighted voting games with fixed k, can be computed in pseudopolynomial time, i.e., there exists an algorithm that ...

  7. Targeting RNA polymerase I transcription and the nucleolus for cancer therapy.

    Science.gov (United States)

    Hannan, Ross D; Drygin, Denis; Pearson, Richard B

    2013-08-01

    The nucleoli are the site of the production of ribosomes, the protein synthetic apparatus of the cell. The presence of enlarged nucleoli, reflecting increased ribosomal gene transcription, has long been used by pathologists as an indicator of aggressive tumors. However, over the last 10 years a growing body of evidence has revealed that the nucleolus contains a dynamic cohort of over 4500 proteins, the majority of which have no function in ribosome production. The activity of some of these proteins is modulated by their regulated sequestration and release from the nucleolus. In particular, the nucleolus plays a central role in sensing cellular stress to modulate the abundance of the critical tumor suppressor protein p53. The finding that p53 activity is dysregulated in up to 50% of all human cancers highlights the importance of the nucleolar stress response in limiting malignant transformation. The development of drugs to selectively inhibit transcription of the ribosomal RNA genes in the nucleolus has paved the way for a new therapeutic approach to hijack nucleolar stress to selectively and non-genotoxically activate p53 in tumor cells. Here, we describe the potential application of this exciting new class of drugs for the treatment of human cancer.

  8. Roles of the nucleolus in the CAG RNA-mediated toxicity.

    Science.gov (United States)

    Tsoi, Ho; Chan, Ho Yin Edwin

    2014-06-01

    The nucleolus is a subnuclear compartment within the cell nucleus that serves as the site for ribosomal RNA (rRNA) transcription and the assembly of ribosome subunits. Apart from its classical role in ribosomal biogenesis, a number of cellular regulatory roles have recently been assigned to the nucleolus, including governing the induction of apoptosis. "Nucleolar stress" is a term that is used to describe a signaling pathway through which the nucleolus communicates with other subcellular compartments, including the mitochondria, to induce apoptosis. It is an effective mechanism for eliminating cells that are incapable of performing protein synthesis efficiently due to ribosome biogenesis defects. The down-regulation of rRNA transcription is a common cause of nucleolar function disruption that subsequently triggers nucleolar stress, and has been associated with the pathogenesis of neurological disorders such as spinocerebellar ataxias (SCAs) and Huntington's diseases (HD). This article discusses recent advances in mechanistic studies of how expanded CAG trinucleotide repeat RNA transcripts trigger nucleolar stress in SCAs, HD and other trinucleotide repeat disorders. This article is part of a Special Issue entitled: Role of the Nucleolus in Human Disease.

  9. Effects of Mg{sup 2+}, Co{sup 2+}, and Hg{sup 2+} on the nucleus and nucleolus in root tip cells of allium cepa

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D.; Jiang, W.; Wang, W. [Tianjin Normal Univ. (China); Zhai, L. [Xinhua High School, Tianjin (China)

    1995-11-01

    Metal toxicity in plants has been known for a long time. Much importance has increasingly been attached to the problems of metal pollution with the development of modern industry and agriculture. If metals in plants are accumulated to a large extent, it might seriously affect them. The cytological effects of cobalt and mercury have been studied in Allium cepa by documentation of c-mitosis. Also, the quantification of chromosome aberration in Vicia faba root-tip cells treated by magnesium sulphate and in Allium cepa by metyl mercury chloride and mercuric chloride has been reported. Cytological research on the poisoning effects of Mg, Co and Hg on the nuclei and nucleoli in root-tip cells of plants has hardly been reported. The aim of this study was to determine the effects of different concentrations of magnesium, cobalt and mercury ions on root growth, and on the nuclei and nucleoli of root tip cells of Allium-cepa. 20 refs., 3 figs.

  10. The nucleolus is well-posed

    Science.gov (United States)

    Fragnelli, Vito; Patrone, Fioravante; Torre, Anna

    2006-02-01

    The lexicographic order is not representable by a real-valued function, contrary to many other orders or preorders. So, standard tools and results for well-posed minimum problems cannot be used. We prove that under suitable hypotheses it is however possible to guarantee the well-posedness of a lexicographic minimum over a compact or convex set. This result allows us to prove that some game theoretical solution concepts, based on lexicographic order are well-posed: in particular, this is true for the nucleolus.

  11. Environmental cues induce a long noncoding RNA-dependent remodeling of the nucleolus.

    Science.gov (United States)

    Jacob, Mathieu D; Audas, Timothy E; Uniacke, James; Trinkle-Mulcahy, Laura; Lee, Stephen

    2013-09-01

    The nucleolus is a plurifunctional organelle in which structure and function are intimately linked. Its structural plasticity has long been appreciated, particularly in response to transcriptional inhibition and other cellular stresses, although the mechanism and physiological relevance of these phenomena are unclear. Using MCF-7 and other mammalian cell lines, we describe a structural and functional adaptation of the nucleolus, triggered by heat shock or physiological acidosis, that depends on the expression of ribosomal intergenic spacer long noncoding RNA (IGS lncRNA). At the heart of this process is the de novo formation of a large subnucleolar structure, termed the detention center (DC). The DC is a spatially and dynamically distinct region, characterized by an 8-anilino-1-naphthalenesulfonate-positive hydrophobic signature. Its formation is accompanied by redistribution of nucleolar factors and arrest in ribosomal biogenesis. Silencing of regulatory IGS lncRNA prevents the creation of this structure and allows the nucleolus to retain its tripartite organization and transcriptional activity. Signal termination causes a decrease in IGS transcript levels and a return to the active nucleolar conformation. We propose that the induction of IGS lncRNA by environmental signals operates as a molecular switch that regulates the structure and function of the nucleolus.

  12. A mRNA and cognate microRNAs localize in the nucleolus.

    Science.gov (United States)

    Reyes-Gutierrez, Pablo; Ritland Politz, Joan C; Pederson, Thoru

    2014-01-01

    We previously discovered that a set of 5 microRNAs are concentrated in the nucleolus of rat myoblasts. We now report that several mRNAs are also localized in the nucleoli of these cells as determined by microarray analysis of RNA from purified nucleoli. Among the most abundant of these nucleolus-localized mRNAs is that encoding insulin-like growth factor 2 (IGF2), a regulator of myoblast proliferation and differentiation. The presence of IGF2 mRNA in nucleoli was confirmed by fluorescence in situ hybridization, and RT-PCR experiments demonstrated that these nucleolar transcripts are spliced, thus arriving from the nucleoplasm. Bioinformatics analysis predicted canonically structured, highly thermodynamically stable interactions between IGF2 mRNA and all 5 of the nucleolus-localized microRNAs. These results raise the possibility that the nucleolus is a staging site for setting up particular mRNA-microRNA interactions prior to export to the cytoplasm.

  13. Advanced microscopy techniques used for comparison of UVA- and γ-irradiation-induced DNA damage in the cell nucleus and nucleolus.

    Science.gov (United States)

    Stixová, L; Hrušková, T; Sehnalová, P; Legartová, S; Svidenská, S; Kozubek, S; Bártová, E

    2014-01-01

    Every day, genomes are affected by genotoxic factors that create multiple DNA lesions. Several DNA repair systems have evolved to counteract the deleterious effects of DNA damage. These systems include a set of DNA repair mechanisms, damage tolerance processes, and activation of cell-cycle checkpoints. This study describes selected confocal microscopy techniques that investigate DNA damage-related nuclear events after UVA- and γ-irradiation and compare the DNA damage response (DDR) induced by the two experimental approaches. In both cases, we observed induction of the nucleotide excision repair (NER) pathway and formation of localized double-strand breaks (DSBs). This was confirmed by analysis of cyclobutane pyrimidine dimers (CPDs) in the DNA lesions and by increased levels of γH2AX and 53BP1 proteins in the irradiated genome. DNA damage by UVA-lasers was potentiated by either BrdU or Hoechst 33342 pre-sensitization and compared to non-photosensitized cells. DSBs were also induced without BrdU or Hoechst 33342 pre-treatment. Interestingly, no cyclobutane pyrimidine dimers (CPDs) were detected after 405 nm UVA laser micro-irradiation in non-photosensitized cells. The effects of UVA and γ-irradiation were also studied by silver staining of nucleolar organizer regions (AgNORs). This experimental approach revealed changes in the morphology of nucleoli after genome injury. Additionally, to precisely characterize DDR in locally induced DNA lesions, we analysed the kinetics of the 53BP1 protein involved in DDR by fluorescence recovery after photobleaching (FRAP).

  14. On the core and f-nucleolus of flow games

    NARCIS (Netherlands)

    Kern, Walter; Paulusma, Daniël

    2009-01-01

    Using the ellipsoid method, both Deng et al. [Deng, X., Q. Fang, X. Sun. 2006. Finding nucleolus of flow game. Proc. 17th ACM-SIAM Sympos. Discrete Algorithms. ACM Press, New York, 124–131] and Potters et al. [Potters, J., H. Reijnierse, A. Biswas. 2006. The nucleolus of balanced simple flow network

  15. Proteomic analysis of the Arabidopsis nucleolus suggests novel nucleolar functions

    DEFF Research Database (Denmark)

    Pendle, Alison F; Clark, Gillian P; Boon, Reinier;

    2005-01-01

    The eukaryotic nucleolus is involved in ribosome biogenesis and a wide range of other RNA metabolism and cellular functions. An important step in the functional analysis of the nucleolus is to determine the complement of proteins of this nuclear compartment. Here, we describe the first proteomic...

  16. Strongly Essential Coalitions and the Nucleolus of Peer Group Games

    NARCIS (Netherlands)

    Brânzei, R.; Solymosi, T.; Tijs, S.H.

    2003-01-01

    Most of the known efficient algorithms designed to compute the nucleolus for special classes of balanced games are based on two facts: (i) in any balanced game, the coalitions which actually determine the nucleolus are essential; and (ii) all essential coalitions in any of the games in the class bel

  17. Changes of the nucleolus architecture in absence of the nuclear factor CTCF.

    Science.gov (United States)

    Hernández-Hernández, A; Soto-Reyes, E; Ortiz, R; Arriaga-Canon, C; Echeverría-Martinez, O M; Vázquez-Nin, G H; Recillas-Targa, F

    2012-01-01

    CTCF is a multifunctional nuclear factor involved in many cellular processes like gene regulation, chromatin insulation and genomic organization. Recently, CTCF has been shown to be involved in the transcriptional regulation of ribosomal genes and nucleolar organization in Drosophila cells and different murine cell types, including embryonic stem cells. Moreover, it has been suggested that CTCF could be associated to the nucleolus of human erythroleukemic K562 cells. In the present work, we took advantage of efficient small hairpin RNA interference against human CTCF to analyze nucleolar organization in HeLa cells. We have found that key components of the nucleolar architecture are altered. As a consequence of such alterations, an upregulation of ribosomal gene transcription was observed. We propose that CTCF contributes to the structural organization of the nucleolus and, through epigenetic mechanisms, to the regulation of the ribosomal gene expression.

  18. Electron Microscopy Analysis of the Nucleolus of Trypanosoma cruzi

    Science.gov (United States)

    López-Velázquez, Gabriel; Hernández, Roberto; López-Villaseñor, Imelda; Reyes-Vivas, Horacio; Segura-Valdez, María De L.; Jiménez-García, Luis F.

    2005-08-01

    The nucleolus is the main site for synthesis and processing of ribosomal RNA in eukaryotes. In mammals, plants, and yeast the nucleolus has been extensively characterized by electron microscopy, but in the majority of the unicellular eukaryotes no such studies have been performed. Here we used ultrastructural cytochemical and immunocytochemical techniques as well as three-dimensional reconstruction to analyze the nucleolus of Trypanosoma cruzi, which is an early divergent eukaryote of medical importance. In T. cruzi epimastigotes the nucleolus is a spherical intranuclear ribonucleoprotein organelle localized in a relatively central position within the nucleus. Dense fibrillar and granular components but not fibrillar centers were observed. In addition, nuclear bodies resembling Cajal bodies were observed associated to the nucleolus in the surrounding nucleoplasm. Our results provide additional morphological data to better understand the synthesis and processing of the ribosomal RNA in kinetoplastids.

  19. Importance of the pluripotency factor LIN28 in the mammalian nucleolus during early embryonic development.

    Science.gov (United States)

    Vogt, Edgar J; Meglicki, Maciej; Hartung, Kristina Ilka; Borsuk, Ewa; Behr, Rüdiger

    2012-12-01

    The maternal nucleolus is required for proper activation of the embryonic genome (EGA) and early embryonic development. Nucleologenesis is characterized by the transformation of a nucleolar precursor body (NPB) to a mature nucleolus during preimplantation development. However, the function of NPBs and the involved molecular factors are unknown. We uncover a novel role for the pluripotency factor LIN28, the biological significance of which was previously demonstrated in the reprogramming of human somatic cells to induced pluripotent stem (iPS) cells. Here, we show that LIN28 accumulates at the NPB and the mature nucleolus in mouse preimplantation embryos and embryonic stem cells (ESCs), where it colocalizes with the nucleolar marker B23 (nucleophosmin 1). LIN28 has nucleolar localization in non-human primate (NHP) preimplantation embryos, but is cytoplasmic in NHP ESCs. Lin28 transcripts show a striking decline before mouse EGA, whereas LIN28 protein localizes to NPBs at the time of EGA. Following knockdown with a Lin28 morpholino, the majority of embryos arrest between the 2- and 4-cell stages and never develop to morula or blastocyst. Lin28 morpholino-injected embryos arrested at the 2-cell stage were not enriched with nucleophosmin at presumptive NPB sites, indicating that functional NPBs were not assembled. Based on these results, we propose that LIN28 is an essential factor of nucleologenesis during early embryonic development.

  20. The nucleoplasmin homolog NLP mediates centromere clustering and anchoring to the nucleolus.

    Science.gov (United States)

    Padeken, Jan; Mendiburo, María José; Chlamydas, Sarantis; Schwarz, Hans-Jürgen; Kremmer, Elisabeth; Heun, Patrick

    2013-04-25

    Centromere clustering during interphase is a phenomenon known to occur in many different organisms and cell types, yet neither the factors involved nor their physiological relevance is well understood. Using Drosophila tissue culture cells and flies, we identified a network of proteins, including the nucleoplasmin-like protein (NLP), the insulator protein CTCF, and the nucleolus protein Modulo, to be essential for the positioning of centromeres. Artificial targeting further demonstrated that NLP and CTCF are sufficient for clustering, while Modulo serves as the anchor to the nucleolus. Centromere clustering was found to depend on centric chromatin rather than specific DNA sequences. Moreover, unclustering of centromeres results in the spatial destabilization of pericentric heterochromatin organization, leading to partial defects in the silencing of repetitive elements, defects during chromosome segregation, and genome instability.

  1. The relationship between the nucleolus and cancer: Current evidence and emerging paradigms.

    Science.gov (United States)

    Orsolic, Ines; Jurada, Deana; Pullen, Nick; Oren, Moshe; Eliopoulos, Aristides G; Volarevic, Sinisa

    2016-06-01

    The nucleolus is the most prominent nuclear substructure assigned to produce ribosomes; molecular machines that are responsible for carrying out protein synthesis. To meet the increased demand for proteins during cell growth and proliferation the cell must increase protein synthetic capacity by upregulating ribosome biogenesis. While larger nucleolar size and number have been recognized as hallmark features of many tumor types, recent evidence has suggested that, in addition to overproduction of ribosomes, decreased ribosome biogenesis as well as qualitative changes in this process could also contribute to tumor initiation and cancer progression. Furthermore, the nucleolus has become the focus of intense attention for its involvement in processes that are clearly unrelated to ribosome biogenesis such as sensing and responding to endogenous and exogenous stressors, maintenance of genome stability, regulation of cell-cycle progression, cellular senescence, telomere function, chromatin structure, establishment of nuclear architecture, global regulation of gene expression and biogenesis of multiple ribonucleoprotein particles. The fact that dysregulation of many of these fundamental cellular processes may contribute to the malignant phenotype suggests that normal functioning of the nucleolus safeguards against the development of cancer and indicates its potential as a therapeutic approach. Here we review the recent advances made toward understanding these newly-recognized nucleolar functions and their roles in normal and cancer cells, and discuss possible future research directions.

  2. Stalled RNAP-II molecules bound to non-coding rDNA spacers are required for normal nucleolus architecture.

    Science.gov (United States)

    Freire-Picos, M A; Landeira-Ameijeiras, V; Mayán, María D

    2013-07-01

    The correct distribution of nuclear domains is critical for the maintenance of normal cellular processes such as transcription and replication, which are regulated depending on their location and surroundings. The most well-characterized nuclear domain, the nucleolus, is essential for cell survival and metabolism. Alterations in nucleolar structure affect nuclear dynamics; however, how the nucleolus and the rest of the nuclear domains are interconnected is largely unknown. In this report, we demonstrate that RNAP-II is vital for the maintenance of the typical crescent-shaped structure of the nucleolar rDNA repeats and rRNA transcription. When stalled RNAP-II molecules are not bound to the chromatin, the nucleolus loses its typical crescent-shaped structure. However, the RNAP-II interaction with Seh1p, or cryptic transcription by RNAP-II, is not critical for morphological changes.

  3. Nucleolus detection in the Fuhrman grading system for application in CCRC.

    Science.gov (United States)

    Kruk, Michal; Osowski, Stanislaw; Markiewicz, Tomasz; Kozlowski, Wojciech; Koktysz, Robert; Slodkowska, Janina; Swiderski, Bartosz

    2014-02-01

    The paper presents a method for nucleolus detection in images of nuclei in clear-cell renal carcinoma (CCRC). The method is based on the similarity of the nuclei image and the two-dimensional paraboloidal window function. The results of numerical experiments performed on almost 2600 images of CCRC nuclei have confirmed the good accuracy of the method. The developed algorithm will be used to accelerate further research in computer-assisted diagnosis of CCRC.

  4. Nepro is localized in the nucleolus and essential for preimplantation development in mice.

    Science.gov (United States)

    Hashimoto, Masakazu; Sato, Tatsuya; Muroyama, Yuko; Fujimura, Lisa; Hatano, Masahiko; Saito, Tetsuichiro

    2015-09-01

    We generated knockout (KO) mice of Nepro, which has been shown to be necessary to maintain neural progenitor cells downstream of Notch in the mouse developing neocortex by using knockdown experiments, to explore its function in embryogenesis. Nepro KO embryos were morphologically indistinguishable from wild type (WT) embryos until the morula stage but failed in blastocyst formation, and many cells of the KO embryos resulted in apoptosis. We found that Nepro was localized in the nucleolus at the blastocyst stage. The number of nucleolus precursor bodies (NPBs) and nucleoli per nucleus was significantly higher in Nepro KO embryos compared with WT embryos later than the 2-cell stage. Furthermore, at the morula stage, whereas 18S rRNA and ribosomal protein S6 (rpS6), which are components of the ribosome, were distributed to the cytoplasm in WT embryos, they were mainly localized in the nucleoli in Nepro KO embryos. In addition, in Nepro KO embryos, the amount of the mitochondria-associated p53 protein increased, and Cytochrome c was distributed in the cytoplasm. These findings indicate that Nepro is a nucleolus-associated protein, and its loss leads to the apoptosis before blastocyst formation in mice.

  5. The nucleolus: an emerging target for cancer therapy.

    Science.gov (United States)

    Hein, Nadine; Hannan, Katherine M; George, Amee J; Sanij, Elaine; Hannan, Ross D

    2013-11-01

    For over 100 years, pathologists have utilised an increase in size and number of nucleoli, the subnuclear site of ribosome synthesis, as a marker of aggressive tumours. Despite this, the contribution of the nucleolus and ribosomal RNA synthesis to cancer has been largely overlooked. This concept has recently changed with the demonstration that the nucleolus indirectly controls numerous other cellular functions, in particular, the cellular activity of the critical tumour suppressor protein, p53. Moreover, selective inhibition of ribosomal gene transcription in the nucleolus has been shown to be an effective therapeutic strategy to promote cancer-specific activation of p53. This article reviews the largely untapped potential of the nucleolus and ribosomal gene transcription as exciting new targets for cancer therapy.

  6. 核仁研究新进展%Advances in the study of the nucleolus

    Institute of Scientific and Technical Information of China (English)

    冯金梅; 孙隽; 文建凡

    2012-01-01

    As the most prominent sub-nuclear compartment in the interphase nucleus and the site of ribosome biogenesis, the nucleolus synthesizes and processes rRNA and also assembles ribosomal subunits. Though several lines of research in recent years have indicated that the nucleolus might have additional functions—such as the assembling of signal recognition particles, the processing of mRNA, tRNA and telomerase activities, and regulating the cell cycle—proteomic analyses of the nucleolus in three representative eukaryotic species has shown that a plethora of proteins either have no association with ribosome biogenesis or are of presently unknown function. This phenomenon further indicates that the composition and function of the nucleolus is far more complicated than previously thought. Meanwhile, the available nucleolar proteome databases has provided new approaches and led to remarkable progress in understanding the nucleolus. Here, we have summarized recent advances in the study of the nucleolus, including new discoveries of its structure, function, genomics/proteomics as well as its origin and evolution. Moreover, we highlight several of the important unresolved issues in this field.%核仁是真核细胞间期核中最显著的结构.其主要功能是进行rRNA的合成和核糖体大、小亚基的装配.然而,近年来的研究提示核仁可能还参与了一系列其他功能活动,如mRNA和tRNA的加工成熟、信号识别颗粒的组装、端粒酶活性和调节细胞周期等.对多个物种核仁蛋白质组数据的分析也显示核仁中具有许多与核糖体生物合成无关以及功能未知的蛋白,表明核仁在组成和功能上远比人们以前的认识复杂.同时,核仁蛋白质组数据的获得也为人们从组学水平研究核仁的起源与进化提供了新视角.该文对近年来在核仁结构、功能、蛋白质/基因组学研究及其起源与进化等方面的进展进行了概述,并探讨了一些有待于进一步研究的问题.

  7. The actin family protein ARP6 contributes to the structure and the function of the nucleolus.

    Science.gov (United States)

    Kitamura, Hiroshi; Matsumori, Haruka; Kalendova, Alzbeta; Hozak, Pavel; Goldberg, Ilya G; Nakao, Mitsuyoshi; Saitoh, Noriko; Harata, Masahiko

    2015-08-21

    The actin family members, consisting of actin and actin-related proteins (ARPs), are essential components of chromatin remodeling complexes. ARP6, one of the nuclear ARPs, is part of the Snf-2-related CREB-binding protein activator protein (SRCAP) chromatin remodeling complex, which promotes the deposition of the histone variant H2A.Z into the chromatin. In this study, we showed that ARP6 influences the structure and the function of the nucleolus. ARP6 is localized in the central region of the nucleolus, and its knockdown induced a morphological change in the nucleolus. We also found that in the presence of high concentrations of glucose ARP6 contributed to the maintenance of active ribosomal DNA (rDNA) transcription by placing H2A.Z into the chromatin. In contrast, under starvation, ARP6 was required for cell survival through the repression of rDNA transcription independently of H2A.Z. These findings reveal novel pleiotropic roles for the actin family in nuclear organization and metabolic homeostasis.

  8. Inverse size scaling of the nucleolus by a concentration-dependent phase transition.

    Science.gov (United States)

    Weber, Stephanie C; Brangwynne, Clifford P

    2015-03-01

    Just as organ size typically increases with body size, the size of intracellular structures changes as cells grow and divide. Indeed, many organelles, such as the nucleus [1, 2], mitochondria [3], mitotic spindle [4, 5], and centrosome [6], exhibit size scaling, a phenomenon in which organelle size depends linearly on cell size. However, the mechanisms of organelle size scaling remain unclear. Here, we show that the size of the nucleolus, a membraneless organelle important for cell-size homeostasis [7], is coupled to cell size by an intracellular phase transition. We find that nucleolar size directly scales with cell size in early C. elegans embryos. Surprisingly, however, when embryo size is altered, we observe inverse scaling: nucleolar size increases in small cells and decreases in large cells. We demonstrate that this seemingly contradictory result arises from maternal loading of a fixed number rather than a fixed concentration of nucleolar components, which condense into nucleoli only above a threshold concentration. Our results suggest that the physics of phase transitions can dictate whether an organelle assembles, and, if so, its size, providing a mechanistic link between organelle assembly and cell size. Since the nucleolus is known to play a key role in cell growth, this biophysical readout of cell size could provide a novel feedback mechanism for growth control.

  9. Maternal factors required for oocyte developmental competence in mice: transcriptome analysis of non-surrounded nucleolus (NSN) and surrounded nucleolus (SN) oocytes.

    Science.gov (United States)

    Ma, Jun-Yu; Li, Mo; Luo, Yi-Bo; Song, Shuhui; Tian, Dongmei; Yang, Jin; Zhang, Bing; Hou, Yi; Schatten, Heide; Liu, Zhonghua; Sun, Qing-Yuan

    2013-06-15

    During mouse antral follicle development, the oocyte chromatin gradually transforms from a less condensed state with no Hoechst-positive rim surrounding the nucleolus (NSN) to a fully condensed chromatin state with a Hoechst-positive rim surrounding the nucleolus (SN). Compared with SN oocytes, NSN oocytes display a higher gene transcription activity and a lower rate of meiosis resumption (G2/M transition), and they are mostly arrested at the two-cell stage after in vitro fertilization. To explore the differences between NSN and SN oocytes, and the maternal factors required for oocyte developmental competence, we compared the whole-transcriptome profiles between NSN and SN oocytes. First, we found that the NSN and SN oocytes were different in their metabolic pathways. In the phosphatidylinositol signaling pathway, the SN oocytes tend to produce diacylglycerol, whereas the NSN oocytes tend to produce phosphatidylinositol (3,4,5)-trisphosphate. For energy production, the SN oocytes and NSN oocytes differed in the gluconeogenesis and in the synthesis processes. Second, we also found that the key genes associated with oocyte meiosis and/or preimplantation embryo development were differently expressed in the NSN and SN oocytes. Our results illustrate that during the NSN-SN transition, the oocytes change their metabolic activities and accumulate maternal factors for further oocyte maturation and post-fertilization embryo development.

  10. On computing the nucleolus of a balanced connected game

    NARCIS (Netherlands)

    Solymosi, Tamás; Aarts, Harry; Driessen, Theo

    1998-01-01

    The question of “fairly” allocating costs or cost-savings among the participants of a joint enterprise is frequently answered by finding the nucleolus of a related cooperative game. In connection with various routing, sequencing and scheduling situations, connected games often arise. Their common fe

  11. Nucleolus-like bodies in the pineal gland of the adult yak (Bos grunniens).

    Science.gov (United States)

    Xie, Zhaohui H; Gan, Ping

    2013-05-28

    The pineal glands of adult yak were studied electron microscopically. Nucleolus-like bodies (NLBs) were found mostly in the pinealocytes and the interstitial cells of the pineal glands of the yak. The NLBs were electron-dense, round or ovoid bodies with a diameter of 50 nm - 500 nm. Two types of granules were identified as melanin. These may correspond to different stages of a progressive storage of melanin. Rough endoplasmic reticula with abundant ribosomes were observed. There was no correlation between the number of NLBs and the sex of the animals.

  12. Analysis of the C. elegans Nucleolus by Immuno-DNA FISH.

    Science.gov (United States)

    Lanctôt, Christian

    2016-01-01

    Caenorhabditis elegans is a well-established model organism which allows, among others, to investigate the link between nucleolar structure/function on the one hand and cell fate choices and cellular differentiation on the other. In addition, C. elegans can be used to study the role of the nucleolus in processes that can be difficult to faithfully reproduce in vitro, such as gametogenesis, disease development, and aging. Here I present two complementary techniques, immunofluorescent staining and DNA fluorescence in situ hybridization, that have been adapted to label nucleolar components at various stages of the life cycle of the worm.

  13. The transcription factor EGR1 localizes to the nucleolus and is linked to suppression of ribosomal precursor synthesis.

    Directory of Open Access Journals (Sweden)

    Donatella Ponti

    Full Text Available EGR1 is an immediate early gene with a wide range of activities as transcription factor, spanning from regulation of cell growth to differentiation. Numerous studies show that EGR1 either promotes the proliferation of stimulated cells or suppresses the tumorigenic growth of transformed cells. Upon interaction with ARF, EGR1 is sumoylated and acquires the ability to bind to specific targets such as PTEN and in turn to regulate cell growth. ARF is mainly localized to the periphery of nucleolus where is able to negatively regulate ribosome biogenesis. Since EGR1 colocalizes with ARF under IGF-1 stimulation we asked the question of whether EGR1 also relocate to the nucleolus to interact with ARF. Here we show that EGR1 colocalizes with nucleolar markers such as fibrillarin and B23 in the presence of ARF. Western analysis of nucleolar extracts from HeLa cells was used to confirm the presence of EGR1 in the nucleolus mainly as the 100 kDa sumoylated form. We also show that the level of the ribosomal RNA precursor 47S is inversely correlated to the level of EGR1 transcripts. The EGR1 iseffective to regulate the synthesis of the 47S rRNA precursor. Then we demonstrated that EGR1 binds to the Upstream Binding Factor (UBF leading us to hypothesize that the regulating activity of EGR1 is mediated by its interaction within the transcriptional complex of RNA polymerase I. These results confirm the presence of EGR1 in the nucleolus and point to a role for EGR1 in the control of nucleolar metabolism.

  14. The transcription factor EGR1 localizes to the nucleolus and is linked to suppression of ribosomal precursor synthesis.

    Science.gov (United States)

    Ponti, Donatella; Bellenchi, Gian Carlo; Puca, Rosa; Bastianelli, Daniela; Maroder, Marella; Ragona, Giuseppe; Roussel, Pascal; Thiry, Marc; Mercola, Dan; Calogero, Antonella

    2014-01-01

    EGR1 is an immediate early gene with a wide range of activities as transcription factor, spanning from regulation of cell growth to differentiation. Numerous studies show that EGR1 either promotes the proliferation of stimulated cells or suppresses the tumorigenic growth of transformed cells. Upon interaction with ARF, EGR1 is sumoylated and acquires the ability to bind to specific targets such as PTEN and in turn to regulate cell growth. ARF is mainly localized to the periphery of nucleolus where is able to negatively regulate ribosome biogenesis. Since EGR1 colocalizes with ARF under IGF-1 stimulation we asked the question of whether EGR1 also relocate to the nucleolus to interact with ARF. Here we show that EGR1 colocalizes with nucleolar markers such as fibrillarin and B23 in the presence of ARF. Western analysis of nucleolar extracts from HeLa cells was used to confirm the presence of EGR1 in the nucleolus mainly as the 100 kDa sumoylated form. We also show that the level of the ribosomal RNA precursor 47S is inversely correlated to the level of EGR1 transcripts. The EGR1 iseffective to regulate the synthesis of the 47S rRNA precursor. Then we demonstrated that EGR1 binds to the Upstream Binding Factor (UBF) leading us to hypothesize that the regulating activity of EGR1 is mediated by its interaction within the transcriptional complex of RNA polymerase I. These results confirm the presence of EGR1 in the nucleolus and point to a role for EGR1 in the control of nucleolar metabolism.

  15. lncRNA maturation to initiate heterochromatin formation in the nucleolus is required for exit from pluripotency in ESCs.

    Science.gov (United States)

    Savić, Nataša; Bär, Dominik; Leone, Sergio; Frommel, Sandra C; Weber, Fabienne A; Vollenweider, Eva; Ferrari, Elena; Ziegler, Urs; Kaech, Andres; Shakhova, Olga; Cinelli, Paolo; Santoro, Raffaella

    2014-12-01

    The open chromatin of embryonic stem cells (ESCs) condenses into repressive heterochromatin as cells exit the pluripotent state. How the 3D genome organization is orchestrated and implicated in pluripotency and lineage specification is not understood. Here, we find that maturation of the long noncoding RNA (lncRNA) pRNA is required for establishment of heterochromatin at ribosomal RNA genes, the genetic component of nucleoli, and this process is inactivated in pluripotent ESCs. By using mature pRNA to tether heterochromatin at nucleoli of ESCs, we find that localized heterochromatin condensation of ribosomal RNA genes initiates establishment of highly condensed chromatin structures outside of the nucleolus. Moreover, we reveal that formation of such highly condensed, transcriptionally repressed heterochromatin promotes transcriptional activation of differentiation genes and loss of pluripotency. Our findings unravel the nucleolus as an active regulator of chromatin plasticity and pluripotency and challenge current views on heterochromatin regulation and function in ESCs.

  16. Role of the nucleolus in neurodegenerative diseases with particular reference to the retina: a review.

    Science.gov (United States)

    Sia, Paul I; Wood, John Pm; Chidlow, Glyn; Sharma, Shiwani; Craig, Jamie; Casson, Robert J

    2016-04-01

    The nucleolus has emerged as a key regulator of cellular growth and the response to stress, in addition to its traditionally understood function in ribosome biogenesis. The association between nucleolar function and neurodegenerative disease is increasingly being explored. There is also recent evidence indicating that the nucleolus may well be crucial in the development of the eye. In this present review, the role of the nucleolus in retinal development as well as in neurodegeneration with an emphasis on the retina is discussed.

  17. Progeria, the nucleolus and farnesyltransferase inhibitors.

    Science.gov (United States)

    Mehta, Ishita S; Bridger, Joanna M; Kill, Ian R

    2010-02-01

    HGPS (Hutchinson-Gilford progeria syndrome) is a rare genetic disease affecting children causing them to age and die prematurely. The disease is typically due to a point mutation in the coding sequence for the nuclear intermediate-type filament protein lamin A and gives rise to a dominant-negative splice variant named progerin. Accumulation of progerin within nuclei causes disruption to nuclear structure, causes and premature replicative senescence and increases apoptosis. Now it appears that accumulation of progerin may have more widespread effects than previously thought since the demonstration that the presence and distribution of some nucleolar proteins are also adversely affected in progeria cells. One of the major breakthroughs both in the lamin field and for this syndrome is that many of the cellular defects observed in HGPS patient cells and model systems can be restored after treatment with a class of compounds known as FTIs (farnesyltransferase inhibitors). Indeed, it is demonstrated that FTI-277 is able to completely restore nucleolar antigen localization in treated progeria cells. This is encouraging news for the HGPS patients who are currently undergoing clinical trials with FTI treatment.

  18. Identification of novel markers that demarcate the nucleolus during severe stress and chemotherapeutic treatment.

    Science.gov (United States)

    Su, Haitong; Kodiha, Mohamed; Lee, Sunghoon; Stochaj, Ursula

    2013-01-01

    The nucleolus, the ribosomal factory of the cell, has emerged as a key player that regulates many aspects of cell biology. Several thousand proteins associate at least transiently with nucleoli, thereby generating a highly dynamic compartment with a protein profile which is sensitive to changes in cell physiology and pharmacological agents. Powerful tools that reliably demarcate the nucleoli are a prerequisite to measure their composition and activities. Previously, we developed quantitative methods to measure fluorescently labeled molecules in nucleoli. While these tools identify nucleoli under control and mild stress conditions, the accurate detection of nucleolar boundaries under harsh experimental conditions is complicated by the lack of appropriate markers for the nucleolar compartment. Using fluorescence microscopy we have now identified new marker proteins to detect nucleoli upon (a) severe stress and (b) drug treatments that trigger a pronounced reorganization of nucleoli. Our results demonstrate that nucleolin is an ideal marker to delimit nucleoli when cells are exposed to heat or oxidative stress. Furthermore, we show for the first time that cellular apoptosis susceptibility protein (CAS) and human antigen R protein (HuR) are excluded from nucleoli and can be employed to delimit these compartments under severe conditions that redistribute major nucleolar proteins. As proof-of-principle, we used these markers to demarcate nucleoli in cells treated with pharmacological compounds that disrupt the nucleolar organization. Furthermore, to gain new insights into the biology of the nucleolus, we applied our protocols and quantified stress- and drug-induced changes in nucleolar organization and function. Finally, we show that CAS, HuR and nucleolin not only identify nucleoli in optical sections, but are also suitable to demarcate the nucleolar border following 3D reconstruction. Taken together, our studies present novel marker proteins that delimit nucleoli with

  19. Nucleolus and its function during viral infection%核仁及其在病毒侵染过程中的作用

    Institute of Scientific and Technical Information of China (English)

    夏丹萍; 燕飞; 陈剑平

    2014-01-01

    核仁是生物体细胞里的重要结构之一,它的主要功能是负责转录rRNA及组装核糖体。病理学研究表明,核仁在病毒侵染细胞过程中也起着重要作用。病毒通过与核仁及其所含组分相互作用而促进病毒粒子的运输,或者利用核仁相关组分来促进病毒的转录与翻译。文章对核仁在病毒侵染过程中的作用作简要概述。%Nucleolus is an important structure of biological cells , responsible for rRNA transcription and assembly of ribosome.Pathological studies reveal that nucleolus also plays important roles in viral infection .Virus can interact with nucleolus or its components to facilitate the transportation of viral particles , transcription and translation of viral genome.Here, we reviewed the progress on function of nucleolus during viral infection briefly .

  20. Nucleolus precursor body (NPB): a distinct structure in mammalian oocytes and zygotes.

    Science.gov (United States)

    Kyogoku, Hirohisa; Kitajima, Tomoya S; Miyano, Takashi

    2014-01-01

    Nucleoli in mammalian oocytes and zygotes, sometimes referred to as nucleolus precursor bodies (NPBs), are compact and morphologically different from nucleoli in somatic cells. We applied a unique NPB analyzing method "enucleolation" technique to zygotes to remove the NPBs. It has been reported that oocyte NPBs are essential for embryonic development; in their absence, the oocytes complete maturation and can be fertilized, but no nucleoli are formed in the zygotes and embryos, leading to developmental failure. However, we found that when NPBs were removed from zygotes, the zygotes developed successfully to live-born pups. These results indicated that oocyte NPBs are essential for embryonic development, but zygote NPBs are not. In addition, the enucleolated zygotes formed somatic-type nucleoli during early embryonic development, demonstrating that somatic-type nucleoli do not originate from zygote NPBs. We summarize our recent investigation on NPBs, and provide additional comments and findings.

  1. The budding yeast nuclear envelope adjacent to the nucleolus serves as a membrane sink during mitotic delay.

    Science.gov (United States)

    Witkin, Keren L; Chong, Yolanda; Shao, Sichen; Webster, Micah T; Lahiri, Sujoy; Walters, Alison D; Lee, Brandon; Koh, Judice L Y; Prinz, William A; Andrews, Brenda J; Cohen-Fix, Orna

    2012-06-19

    The mechanisms that dictate nuclear shape are largely unknown. Here we screened the budding yeast deletion collection for mutants with abnormal nuclear shape. A common phenotype was the appearance of a nuclear extension, particularly in mutants in DNA repair and chromosome segregation genes. Our data suggest that these mutations led to the abnormal nuclear morphology indirectly, by causing a checkpoint-induced cell-cycle delay. Indeed, delaying cells in mitosis by other means also led to the appearance of nuclear extensions, whereas inactivating the DNA damage checkpoint pathway in a DNA repair mutant reduced the fraction of cells with nuclear extensions. Formation of a nuclear extension was specific to a mitotic delay, because cells arrested in S or G2 had round nuclei. Moreover, the nuclear extension always coincided with the nucleolus, while the morphology of the DNA mass remained largely unchanged. Finally, we found that phospholipid synthesis continued unperturbed when cells delayed in mitosis, and inhibiting phospholipid synthesis abolished the formation of nuclear extensions. Our data suggest a mechanism that promotes nuclear envelope expansion during mitosis. When mitotic progression is delayed, cells sequester the added membrane to the nuclear envelope associated with the nucleolus, possibly to avoid disruption of intranuclear organization.

  2. Identification of nucleolus-localized PTEN and its function in regulating ribosome biogenesis.

    Science.gov (United States)

    Li, Pingdong; Wang, Danni; Li, Haiyang; Yu, Zhenkun; Chen, Xiaohong; Fang, Jugao

    2014-10-01

    The tumor suppressor PTEN is a lipid phosphatase that is found mutated in different types of human cancers. PTEN suppresses cell proliferation by inhibiting the PI3K-Akt signaling pathway at the cell membrane. However, PTEN is also demonstrated to localize in the cell nucleus where it exhibits tumor suppressive activity via a different, unknown mechanism. In this study we report that PTEN also localizes to the nucleolus and that nucleolar PTEN plays an important role in regulating nucleolar homeostasis and maintaining nucleolar morphology. Overexpression of nuclear PTEN in PTEN null cells inhibits Akt phosphorylation and reduces cell size. Knockdown of PTEN in PTEN positive cells leads to nucleolar morphologic changes and an increase in the proportion of cells with a greater number of nucleoli. In addition, knockdown of PTEN in PTEN positive cells increased ribosome biogenesis. These findings expand current understanding of function and relevance of nuclear localized PTEN and provide a foundation for the development of novel therapies targeting PTEN.

  3. The nucleolus stress response is coupled to an ATR-Chk1-mediated G2 arrest.

    Science.gov (United States)

    Ma, Hanhui; Pederson, Thoru

    2013-05-01

    We report experiments on the connection between nucleolar stress and cell cycle progression, using HeLa cells engineered with the fluorescent ubiquitinylation-based cell cycle indicator. Nucleolar stress elicited by brief exposure of cells to a low concentration of actinomycin D that selectively inhibits rRNA synthesis had no effect on traverse of G1 or S, but stalled cells in very late interphase. Additional experiments revealed that a switch occurs during a specific temporal window during nucleolar stress and that the subsequent cell cycle arrest is not triggered simply by the stress-induced decline in the synthesis of rRNA or by a ribosome starvation phenomenon. Further experiments revealed that this nucleolus stress-induced cell cycle arrest involves the action of a G2 checkpoint mediated by the ataxia telangiectasia and Rad3-related protein (ATR)-checkpoint kinase 1 (Chk1) pathway. Based on analysis of the cell cycle stages at which this nucleolar stress effect is put into action, to become manifest later, our results demonstrate a feedforward mechanism that leads to G2 arrest and identify ATR and Chk1 as molecular agents of the requisite checkpoint.

  4. El nucléolo como un regulador del envejecimiento celular The nucleolus as a regulator of cellular senescence

    Directory of Open Access Journals (Sweden)

    María Rosete

    2007-04-01

    codifying for damaged rRNA, and the mutations in DNA helicases, which minimizes the formation of DNA extra-chromosomal circles codifying for rRNA, modify the nucleolar structure and induce premature senescence in yeast. Similarly, in humans, the reduction of these DNA helicases levels, which are localized in the nucleoli and participate in maintenance of genomic integrity, helps to the development of those diseases associated with premature senescence. Furthermore, the presence in the nucleolus of some telomerase components, indicates that part of the biosynthesis of this enzyme occurred in this nuclear structure; suggesting a communication between the nucleolus and the synthesis of the telomeres in the regulation of cell senescence. On the other hand, the nucleolus sequesters proteins to regulate its own biological activity, from the start to the end of cellular replication. In addition this nuclear structure is involved in the biosynthesis of most cellular ribonucleoprotein particles, as well as in cell cycle regulation, making it central to gene expression. In conclusion, the nucleolus became a multifunctional subnuclear structure involved from cell proliferation to cell senescence.

  5. Tissue-specific features of the X chromosome and nucleolus spatial dynamics in a malaria mosquito, Anopheles atroparvus

    Science.gov (United States)

    Bondarenko, Semen M.; Artemov, Gleb N.; Stegniy, Vladimir N.

    2017-01-01

    Spatial organization of chromosome territories is important for maintenance of genomic stability and regulation of gene expression. Recent studies have shown tissue-specific features of chromosome attachments to the nuclear envelope in various organisms including malaria mosquitoes. However, other spatial characteristics of nucleus organization, like volume and shape of chromosome territories, have not been studied in Anopheles. We conducted a thorough analysis of tissue-specific features of the X chromosome and nucleolus volume and shape in follicular epithelium and nurse cells of the Anopheles atroparvus ovaries using a modern open-source software. DNA of the polytene X chromosome from ovarian nurse cells was obtained by microdissection and was used as a template for amplification with degenerate oligo primers. A fluorescently labeled X chromosome painting probe was hybridized with formaldehyde-fixed ovaries of mosquitoes using a 3D-FISH method. The nucleolus was stained by immunostaining with an anti-fibrillarin antibody. The analysis was conducted with TANGO—a software for a chromosome spatial organization analysis. We show that the volume and position of the X chromosome have tissue-specific characteristics. Unlike nurse cell nuclei, the growth of follicular epithelium nuclei is not accompanied with the proportional growth of the X chromosome. However, the shape of the X chromosome does not differ between the tissues. The dynamics of the X chromosome attachment regions location is tissue-specific and it is correlated with the process of nucleus growth in follicular epithelium and nurse cells. PMID:28158219

  6. Nucleolus-derived mediators in oncogenic stress response and activation of p53-dependent pathways.

    Science.gov (United States)

    Stępiński, Dariusz

    2016-08-01

    Rapid growth and division of cells, including tumor ones, is correlated with intensive protein biosynthesis. The output of nucleoli, organelles where translational machineries are formed, depends on a rate of particular stages of ribosome production and on accessibility of elements crucial for their effective functioning, including substrates, enzymes as well as energy resources. Different factors that induce cellular stress also often lead to nucleolar dysfunction which results in ribosome biogenesis impairment. Such nucleolar disorders, called nucleolar or ribosomal stress, usually affect cellular functioning which in fact is a result of p53-dependent pathway activation, elicited as a response to stress. These pathways direct cells to new destinations such as cell cycle arrest, damage repair, differentiation, autophagy, programmed cell death or aging. In the case of impaired nucleolar functioning, nucleolar and ribosomal proteins mediate activation of the p53 pathways. They are also triggered as a response to oncogenic factor overexpression to protect tissues and organs against extensive proliferation of abnormal cells. Intentional impairment of any step of ribosome biosynthesis which would direct the cells to these destinations could be a strategy used in anticancer therapy. This review presents current knowledge on a nucleolus, mainly in relation to cancer biology, which is an important and extremely sensitive element of the mechanism participating in cellular stress reaction mediating activation of the p53 pathways in order to counteract stress effects, especially cancer development.

  7. 洋葱细胞核仁内DNA的结构变化及排布过程%The Structural Transformation of Nucleolar DNA and Its Arrangement in Nucleolus of Allium cepa Cells

    Institute of Scientific and Technical Information of China (English)

    陶伟; 张立勇; 黄百渠; 焦明大; 何孟元; 郝水

    2001-01-01

    By using the DNA specific cytochemical staining method (NAMA_Ur) and conventional electron microscopic technique, the authors examined the configuration of intranucleolar DNA in Allium cepa L. cells and found that nucleolar DNA within the fibrillar center (FC) underwent a structural transformation process from condensed to extended state. The authors' observations also displayed a continuous arrangement process of nucleolar DNA, i.e., the extranucleolar DNA entered FC through the nucleolar organizer region (NOR) channel, then extended to the periphery of FC or to the border between FC and dense fibrillar component (DFC), and distributed along the periphery of FC. Thence, by passing through the NOR channel between FCs, the nucleolar DNA continued to transfer to other FCs and arranged in the same above_mentioned forms.%以洋葱(Allium cepa L.) 细胞为研究材料,应用DNA细胞化学特异染色方法(NAMA_Ur)及常规电子显微镜技术,观察了洋葱细胞核仁FC(纤维中心)内DNA的超微结构,发现FC内DNA存在着一个介于集缩到解集缩之间的变化过程,并揭示了DNA在核仁内的连续排布过程,即核仁外DNA经过核仁通道进入到FC后,继续沿FC的边缘或DFC(致密纤维成分)与FC的交界处环绕FC而排布,再经FC之间的核仁通道,延伸到另外的FC区域。

  8. ATM-dependent E2F1 accumulation in the nucleolus is an indicator of ribosomal stress in early response to DNA damage.

    Science.gov (United States)

    Jin, Ya-Qiong; An, Guo-Shun; Ni, Ju-Hua; Li, Shu-Yan; Jia, Hong-Ti

    2014-01-01

    The nucleolus plays a major role in ribosome biogenesis. Most genotoxic agents disrupt nucleolar structure and function, which results in the stabilization/activation of p53, inducing cell cycle arrest or apoptosis. Likewise, transcription factor E2F1 as a DNA damage responsive protein also plays roles in cell cycle arrest, DNA repair, or apoptosis in response to DNA damage through transcriptional response and protein-protein interaction. Furthermore, E2F1 is known to be involved in regulating rRNA transcription. However, how E2F1 displays in coordinating DNA damage and nucleolar stress is unclear. In this study, we demonstrate that ATM-dependent E2F1 accumulation in the nucleolus is a characteristic feature of nucleolar stress in early response to DNA damage. We found that at the early stage of DNA damage, E2F1 accumulation in the nucleolus was an ATM-dependent and a common event in p53-suficient and -deficient cells. Increased nucleolar E2F1 was sequestered by the nucleolar protein p14ARF, which repressed E2F1-dependent rRNA transcription initiation, and was coupled with S phase. Our data indicate that early accumulation of E2F1 in the nucleolus is an indicator for nucleolar stress and a component of ATM pathway, which presumably buffers elevation of E2F1 in the nucleoplasm and coordinates the diversifying mechanisms of E2F1 acts in cell cycle progression and apoptosis in early response to DNA damage.

  9. Nucleolus organizer regions (Nor loci) of Chinese wheats

    Institute of Scientific and Technical Information of China (English)

    Cedric E.May; 辛志勇

    1996-01-01

    Nucleolus organizer regions (Nor loci) of a range of Chinese wheat landraces and cultivars (Triticum aestivum L. em Thell.) were analysed using genomic DNA extracted from leaves. Only two allelic variants of the Nor-B1 locus were found on chromosome 1B (Nor-B1a and Nor-B1g), while Nor-B1g was probably introduced from North America in the early 1960s. The even more recent introduction of the rye allele Nor-R1 in the early 1980s was also revealed. Eight allelic variants of the Nor-B2 locus on chromosome 6B (Nor-B2a, b, d, f, h, o, p and s) were identified. A Chinese origin for the a, d, f, o, p and s alkies is evident although the d allele was successfully introduced into Australian wheats in the early 1900s. Nor-B2h and Nor-B2b are again very recent introductions into Chinese wheat breeding programs, the former from CIMMYT wheats and the latter in association with the introduction of the 1RS/1BL translocation from Europe. On the basis of the presence of different combinations of Nor-B1 and Nor-B2 alleles

  10. Cytogenetic and identification of the nucleolus organizer region in Heliconia bihai (L. L.

    Directory of Open Access Journals (Sweden)

    Heloisa Rocha do Nascimento

    2014-08-01

    Full Text Available The genus Heliconia is not much studied and the number of existing species in this genus is still uncertain. It is known that this number relies between 150 to 250 species. In Brazil, about 40 species are native and known by many different names. The objective of this paper was to characterize morphometrically and to identify the NOR (active nucleolus organizer regions by Ag-NOR banding of chromosomes of Heliconia bihai (L L. Root meristems were submitted to blocking treatment in an amiprofos-methyl (APM solution, fixed in methanol-acetic acid solution for 24 hours, at least. The meristems were washed in distilled water and submitted to enzymatic digestion with pectinase enzyme. The slides were prepared by dissociation of the root meristem, dried in the air and also on hot plate at 50°C. Subsequently, some slides were submitted to 5% Giemsa stain for karyotype construction and to a solution of silver nitrate (AgNO3 50% for Ag-NOR banding. The species H. bihai has 2n = 22 chromosomes, 4 pairs of submetacentric chromosomes and 7 pairs of metacentric chromosomes, and graded medium to short (3.96 to 0.67 μM, with the presence of active NOR in pairs 1 and 2 and interphase cells with 2 nucleoli. These are the features of a diploid species.

  11. Insulin/IGF1-PI3K-dependent nucleolar localization of a glycolytic enzyme--phosphoglycerate mutase 2, is necessary for proper structure of nucleolus and RNA synthesis.

    Science.gov (United States)

    Gizak, Agnieszka; Grenda, Marcin; Mamczur, Piotr; Wisniewski, Janusz; Sucharski, Filip; Silberring, Jerzy; McCubrey, James A; Wisniewski, Jacek R; Rakus, Dariusz

    2015-07-10

    Phosphoglycerate mutase (PGAM), a conserved, glycolytic enzyme has been found in nucleoli of cancer cells. Here, we present evidence that accumulation of PGAM in the nucleolus is a universal phenomenon concerning not only neoplastically transformed but also non-malignant cells. Nucleolar localization of the enzyme is dependent on the presence of the PGAM2 (muscle) subunit and is regulated by insulin/IGF-1-PI3K signaling pathway as well as drugs influencing ribosomal biogenesis. We document that PGAM interacts with several 40S and 60S ribosomal proteins and that silencing of PGAM2 expression results in disturbance of nucleolar structure, inhibition of RNA synthesis and decrease of the mitotic index of squamous cell carcinoma cells. We conclude that presence of PGAM in the nucleolus is a prerequisite for synthesis and initial assembly of new pre-ribosome subunits.

  12. Non-canonical Cajal bodies form in the nucleus of late stage avian oocytes lacking functional nucleolus.

    Science.gov (United States)

    Khodyuchenko, Tatiana; Gaginskaya, Elena; Krasikova, Alla

    2012-07-01

    In the somatic cell nucleus, there are several universal domains such as nucleolus, SC35-domains, Cajal bodies (CBs) and histone locus bodies (HLBs). Among them, CBs were described more than 100 years ago; however, we still do not have a final understanding of their nature and biological significance. The giant nucleus of avian and amphibian growing oocytes represents an advantageous model for analysis of functions and biogenesis of various nuclear domains. Nevertheless, in large-sized avian oocytes that contain transcriptionally active lampbrush chromosomes, CB-like organelles have not been identified yet. Here we demonstrate that in the pigeon (Columba livia) oocyte nucleus, characterized by absence of any functional nucleoli, extrachromosomal spherical bodies contain TMG-capped spliceosomal snRNAs, core proteins of Sm snRNPs and the protein coilin typical for CBs, but not splicing factor SC35 nor the histone pre-mRNA 3'-end processing factor symplekin. The results establish that coilin-rich nuclear organelles in pigeon late-stage oocyte are not the equivalents of HLBs but belong to a group of CBs. At the same time, they do not contain the snoRNP/scaRNP protein fibrillarin involved in 2'-O-methylation of snoRNAs and snRNAs. Thus, the nucleus of late-stage pigeon oocytes houses CB-like organelles that have an unusual molecular composition and are implicated in the snRNP biogenesis pathway. These data demonstrate that snRNP-rich non-canonical CBs can form in the absence of nucleolus. We argue that pigeon oocytes represent a new promising model to investigate CB modular organization, functions and formation mechanism.

  13. RNA-Seq of the nucleolus reveals abundant SNORD44-derived small RNAs.

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    Baoyan Bai

    Full Text Available Small non-coding RNAs represent RNA species that are not translated to proteins, but which have diverse and broad functional activities in physiological and pathophysiological states. The knowledge of these small RNAs is rapidly expanding in part through the use of massive parallel (deep sequencing efforts. We present here the first deep sequencing of small RNomes in subcellular compartments with particular emphasis on small RNAs (sRNA associated with the nucleolus. The vast majority of the cellular, cytoplasmic and nuclear sRNAs were identified as miRNAs. In contrast, the nucleolar sRNAs had a unique size distribution consisting of 19-20 and 25 nt RNAs, which were predominantly composed of small snoRNA-derived box C/D RNAs (termed as sdRNA. Sequences from 47 sdRNAs were identified, which mapped to both 5' and 3' ends of the snoRNAs, and retained conserved box C or D motifs. SdRNA reads mapping to SNORD44 comprised 74% of all nucleolar sdRNAs, and were confirmed by Northern blotting as comprising both 20 and 25 nt RNAs. A novel 120 nt SNORD44 form was also identified. The expression of the SNORD44 sdRNA and 120 nt form was independent of Dicer/Drosha-mediated processing pathways but was dependent on the box C/D snoRNP proteins/sno-ribonucleoproteins fibrillarin and NOP58. The 120 nt SNORD44-derived RNA bound to fibrillarin suggesting that C/D sno-ribonucleoproteins are involved in regulating the stability or processing of SNORD44. This study reveals sRNA cell-compartment specific expression and the distinctive unique composition of the nucleolar sRNAs.

  14. RNA-Seq of the nucleolus reveals abundant SNORD44-derived small RNAs.

    Science.gov (United States)

    Bai, Baoyan; Yegnasubramanian, Srinivasan; Wheelan, Sarah J; Laiho, Marikki

    2014-01-01

    Small non-coding RNAs represent RNA species that are not translated to proteins, but which have diverse and broad functional activities in physiological and pathophysiological states. The knowledge of these small RNAs is rapidly expanding in part through the use of massive parallel (deep) sequencing efforts. We present here the first deep sequencing of small RNomes in subcellular compartments with particular emphasis on small RNAs (sRNA) associated with the nucleolus. The vast majority of the cellular, cytoplasmic and nuclear sRNAs were identified as miRNAs. In contrast, the nucleolar sRNAs had a unique size distribution consisting of 19-20 and 25 nt RNAs, which were predominantly composed of small snoRNA-derived box C/D RNAs (termed as sdRNA). Sequences from 47 sdRNAs were identified, which mapped to both 5' and 3' ends of the snoRNAs, and retained conserved box C or D motifs. SdRNA reads mapping to SNORD44 comprised 74% of all nucleolar sdRNAs, and were confirmed by Northern blotting as comprising both 20 and 25 nt RNAs. A novel 120 nt SNORD44 form was also identified. The expression of the SNORD44 sdRNA and 120 nt form was independent of Dicer/Drosha-mediated processing pathways but was dependent on the box C/D snoRNP proteins/sno-ribonucleoproteins fibrillarin and NOP58. The 120 nt SNORD44-derived RNA bound to fibrillarin suggesting that C/D sno-ribonucleoproteins are involved in regulating the stability or processing of SNORD44. This study reveals sRNA cell-compartment specific expression and the distinctive unique composition of the nucleolar sRNAs.

  15. Localization of α-Dystrobrevin in Cajal Bodies and Nucleoli: A New Role for α-Dystrobrevin in the Structure/Stability of the Nucleolus.

    Science.gov (United States)

    Hernández-Ibarra, Jose Anselmo; Laredo-Cisneros, Marco Samuel; Mondragón-González, Ricardo; Santamaría-Guayasamín, Natalie; Cisneros, Bulmaro

    2015-12-01

    α-Dystrobrevin (α-DB) is a cytoplasmic component of the dystrophin-associated complex involved in cell signaling; however, its recently revealed nuclear localization implies a role for this protein in the nucleus. Consistent with this, we demonstrated, in a previous work that α-DB1 isoform associates with the nuclear lamin to maintain nuclei morphology. In this study, we show the distribution of the α-DB2 isoform in different subnuclear compartments of N1E115 neuronal cells, including nucleoli and Cajal bodies, where it colocalizes with B23/nucleophosmin and Nopp140 and with coilin, respectively. Recovery in a pure nucleoli fraction undoubtedly confirms the presence of α-DB2 in the nucleolus. α-DB2 redistributes in a similar fashion to that of fibrillarin and Nopp140 upon actinomycin-mediated disruption of nucleoli and to that of coilin after disorganization of Cajal bodies through ultraviolet-irradiation, with relocalization of the proteins to the corresponding reassembled structures after cessation of the insults, which implies α-DB2 in the plasticity of these nuclear bodies. That localization of α-DB2 in the nucleolus is physiologically relevant is demonstrated by the fact that downregulation of α-DB2 resulted in both altered nucleoli structure and decreased levels of B23/nucleophosmin, fibrillarin, and Nopp140. Since α-DB2 interacts with B23/nucleophosmin and overexpression of the latter protein favors nucleolar accumulation of α-DB2, it appears that targeting of α-DB2 to the nucleolus is dependent on B23/nucleophosmin. In conclusion, we show for the first time localization of α-DB2 in nucleoli and Cajal bodies and provide evidence that α-DB2 is involved in the structure of nucleoli and might modulate nucleolar functions.

  16. C1q protein binds to the apoptotic nucleolus and causes C1 protease degradation of nucleolar proteins.

    Science.gov (United States)

    Cai, Yitian; Teo, Boon Heng Dennis; Yeo, Joo Guan; Lu, Jinhua

    2015-09-11

    In infection, complement C1q recognizes pathogen-congregated antibodies and elicits complement activation. Among endogenous ligands, C1q binds to DNA and apoptotic cells, but whether C1q binds to nuclear DNA in apoptotic cells remains to be investigated. With UV irradiation-induced apoptosis, C1q initially bound to peripheral cellular regions in early apoptotic cells. By 6 h, binding concentrated in the nuclei to the nucleolus but not the chromatins. When nucleoli were isolated from non-apoptotic cells, C1q also bound to these structures. In vivo, C1q exists as the C1 complex (C1qC1r2C1s2), and C1q binding to ligands activates the C1r/C1s proteases. Incubation of nucleoli with C1 caused degradation of the nucleolar proteins nucleolin and nucleophosmin 1. This was inhibited by the C1 inhibitor. The nucleoli are abundant with autoantigens. C1q binding and C1r/C1s degradation of nucleolar antigens during cell apoptosis potentially reduces autoimmunity. These findings help us to understand why genetic C1q and C1r/C1s deficiencies cause systemic lupus erythematosus.

  17. Local chromatin structure of heterochromatin regulates repeated DNA stability, nucleolus structure, and genome integrity

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    Peng, Jamy C. [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Heterochromatin constitutes a significant portion of the genome in higher eukaryotes; approximately 30% in Drosophila and human. Heterochromatin contains a high repeat DNA content and a low density of protein-encoding genes. In contrast, euchromatin is composed mostly of unique sequences and contains the majority of single-copy genes. Genetic and cytological studies demonstrated that heterochromatin exhibits regulatory roles in chromosome organization, centromere function and telomere protection. As an epigenetically regulated structure, heterochromatin formation is not defined by any DNA sequence consensus. Heterochromatin is characterized by its association with nucleosomes containing methylated-lysine 9 of histone H3 (H3K9me), heterochromatin protein 1 (HP1) that binds H3K9me, and Su(var)3-9, which methylates H3K9 and binds HP1. Heterochromatin formation and functions are influenced by HP1, Su(var)3-9, and the RNA interference (RNAi) pathway. My thesis project investigates how heterochromatin formation and function impact nuclear architecture, repeated DNA organization, and genome stability in Drosophila melanogaster. H3K9me-based chromatin reduces extrachromosomal DNA formation; most likely by restricting the access of repair machineries to repeated DNAs. Reducing extrachromosomal ribosomal DNA stabilizes rDNA repeats and the nucleolus structure. H3K9me-based chromatin also inhibits DNA damage in heterochromatin. Cells with compromised heterochromatin structure, due to Su(var)3-9 or dcr-2 (a component of the RNAi pathway) mutations, display severe DNA damage in heterochromatin compared to wild type. In these mutant cells, accumulated DNA damage leads to chromosomal defects such as translocations, defective DNA repair response, and activation of the G2-M DNA repair and mitotic checkpoints that ensure cellular and animal viability. My thesis research suggests that DNA replication, repair, and recombination mechanisms in heterochromatin differ from those in

  18. A chemokine targets the nucleus: Cxcl12-gamma isoform localizes to the nucleolus in adult mouse heart.

    Directory of Open Access Journals (Sweden)

    Raul Torres

    Full Text Available Chemokines are extracellular mediators of complex regulatory circuits involved principally in cell-to-cell communication. Most studies to date of the essential chemokine Cxcl12 (Sdf-1 have focused on the ubiquitously expressed secreted isoforms alpha and beta. Here we show that, unlike these isoforms and all other known chemokines, the alternatively transcribed gamma isoform is an intracellular protein that localizes to the nucleolus in differentiated mouse Cardiac tissue. Our results demonstrate that nucleolar transportation is encoded by a nucleolar-localization signal in the unique carboxy-terminal region of Sdf-1gamma, and is competent both in vivo and in vitro. The molecular mechanism underlying these unusual chemokine properties involves cardiac-specific transcription of an mRNA containing a unique short-leader sequence lacking the signal peptide and translation from a non-canonical CUG codon. Our results provide an example of genome economy even for essential and highly conserved genes such as Cxcl12, and suggest that chemokines can exert tissue specific functions unrelated to cell-to-cell communication.

  19. Histone H1 of Trypanosoma cruzi is concentrated in the nucleolus region and disperses upon phosphorylation during progression to mitosis.

    Science.gov (United States)

    Gutiyama, Luciana M; da Cunha, Julia P Chagas; Schenkman, Sergio

    2008-04-01

    Phosphorylation of histone H1 is intimately related to the cell cycle progression in higher eukaryotes, reaching maximum levels during mitosis. We have previously shown that in the flagellated protozoan Trypanosoma cruzi, which does not condense chromatin during mitosis, histone H1 is phosphorylated at a single cyclin-dependent kinase site. By using an antibody that recognizes specifically the phosphorylated T. cruzi histone H1 site, we have now confirmed that T. cruzi histone H1 is also phosphorylated in a cell cycle-dependent manner. Differently from core histones, the bulk of nonphosphorylated histone H1 in G(1) and S phases of the cell cycle is concentrated in the central regions of the nucleus, which contains the nucleolus and less densely packed chromatin. When cells pass G(2), histone H1 becomes phosphorylated and starts to diffuse. At the onset of mitosis, histone H1 phosphorylation is maximal and found in the entire nuclear space. As permeabilized parasites preferentially lose phosphorylated histone H1, we conclude that this modification promotes its release from less condensed and nucleolar chromatin after G(2).

  20. The NEDD8 inhibitor MLN4924 increases the size of the nucleolus and activates p53 through the ribosomal-Mdm2 pathway.

    Science.gov (United States)

    Bailly, A; Perrin, A; Bou Malhab, L J; Pion, E; Larance, M; Nagala, M; Smith, P; O'Donohue, M-F; Gleizes, P-E; Zomerdijk, J; Lamond, A I; Xirodimas, D P

    2016-01-28

    The ubiquitin-like molecule NEDD8 is essential for viability, growth and development, and is a potential target for therapeutic intervention. We found that the small molecule inhibitor of NEDDylation, MLN4924, alters the morphology and increases the surface size of the nucleolus in human and germline cells of Caenorhabditis elegans in the absence of nucleolar fragmentation. SILAC proteomics and monitoring of rRNA production, processing and ribosome profiling shows that MLN4924 changes the composition of the nucleolar proteome but does not inhibit RNA Pol I transcription. Further analysis demonstrates that MLN4924 activates the p53 tumour suppressor through the RPL11/RPL5-Mdm2 pathway, with characteristics of nucleolar stress. The study identifies the nucleolus as a target of inhibitors of NEDDylation and provides a mechanism for p53 activation upon NEDD8 inhibition. It also indicates that targeting the nucleolar proteome without affecting nucleolar transcription initiates the required signalling events for the control of cell cycle regulators.

  1. The Giant Cell.

    Science.gov (United States)

    Stockdale, Dennis

    1998-01-01

    Provides directions for the construction of giant plastic cells, including details for building and installing the organelles. Also contains instructions for preparing the ribosomes, nucleolus, nucleus, and mitochondria. (DDR)

  2. Intertissue Control of the Nucleolus via a Myokine-Dependent Longevity Pathway

    Directory of Open Access Journals (Sweden)

    Fabio Demontis

    2014-06-01

    Full Text Available Recent evidence indicates that skeletal muscle influences systemic aging, but little is known about the signaling pathways and muscle-released cytokines (myokines responsible for this intertissue communication. Here, we show that muscle-specific overexpression of the transcription factor Mnt decreases age-related climbing defects and extends lifespan in Drosophila. Mnt overexpression in muscle autonomously decreases the expression of nucleolar components and systemically decreases rRNA levels and the size of the nucleolus in adipocytes. This nonautonomous control of the nucleolus, a regulator of ribosome biogenesis and lifespan, relies on Myoglianin, a myokine induced by Mnt and orthologous to human GDF11 and Myostatin. Myoglianin overexpression in muscle extends lifespan and decreases nucleolar size in adipocytes by activating p38 mitogen-activated protein kinase (MAPK, whereas Myoglianin RNAi in muscle has converse effects. Altogether, these findings highlight a key role for myokine signaling in the integration of signaling events in muscle and distant tissues during aging.

  3. Intertissue control of the nucleolus via a myokine-dependent longevity pathway.

    Science.gov (United States)

    Demontis, Fabio; Patel, Vishal K; Swindell, William R; Perrimon, Norbert

    2014-06-12

    Recent evidence indicates that skeletal muscle influences systemic aging, but little is known about the signaling pathways and muscle-released cytokines (myokines) responsible for this intertissue communication. Here, we show that muscle-specific overexpression of the transcription factor Mnt decreases age-related climbing defects and extends lifespan in Drosophila. Mnt overexpression in muscle autonomously decreases the expression of nucleolar components and systemically decreases rRNA levels and the size of the nucleolus in adipocytes. This nonautonomous control of the nucleolus, a regulator of ribosome biogenesis and lifespan, relies on Myoglianin, a myokine induced by Mnt and orthologous to human GDF11 and Myostatin. Myoglianin overexpression in muscle extends lifespan and decreases nucleolar size in adipocytes by activating p38 mitogen-activated protein kinase (MAPK), whereas Myoglianin RNAi in muscle has converse effects. Altogether, these findings highlight a key role for myokine signaling in the integration of signaling events in muscle and distant tissues during aging.

  4. Nucleolus-tethering system (NoTS) reveals that assembly of photobodies follows a self-organization model.

    Science.gov (United States)

    Liu, Yin; Liu, Qi; Yan, Qingqing; Shi, Leilei; Fang, Yuda

    2014-04-01

    Protein-protein interactions play essential roles in regulating many biological processes. At the cellular level, many proteins form nuclear foci known as nuclear bodies in which many components interact with each other. Photobodies are nuclear bodies containing proteins for light-signaling pathways in plants. What initiates the formation of photobodies is poorly understood. Here we develop a nucleolar marker protein nucleolin2 (Nuc2)-based method called the nucleolus-tethering system (NoTS) by artificially tethering a protein of interest to the nucleolus to analyze the initiation of photobodies. A candidate initiator is evaluated by visualizing whether a protein fused with Nuc2 forms body-like structures at the periphery of the nucleolus, and other components are recruited to the de novo-formed bodies. The interaction between two proteins can also be revealed through relocation and recruitment of interacting proteins to the nucleolus. Using the NoTS, we test the interactions among components in photobodies. In addition, we demonstrate that components of photobodies such as CONSTITUTIVELY PHOTOMORPHOGENIC 1, photoreceptors, and transcription factors tethered to the nucleolus have the capacity to form body-like structures at the periphery of the nucleolus, which contain other components of photobodies, suggesting a self-organization model for the biogenesis of photobodies.

  5. Catalytically active telomerase holoenzyme is assembled in the dense fibrillar component of the nucleolus during S phase.

    Science.gov (United States)

    Lee, Ji Hoon; Lee, Yang Sin; Jeong, Sun Ah; Khadka, Prabhat; Roth, Jürgen; Chung, In Kwon

    2014-02-01

    The maintenance of human telomeres requires the ribonucleoprotein enzyme telomerase, which is composed of telomerase reverse transcriptase (TERT), telomerase RNA component, and several additional proteins for assembly and activity. Telomere elongation by telomerase in human cancer cells involves multiple steps including telomerase RNA biogenesis, holoenzyme assembly, intranuclear trafficking, and telomerase recruitment to telomeres. Although telomerase has been shown to accumulate in Cajal bodies for association with telomeric chromatin, it is unclear where and how the assembly and trafficking of catalytically active telomerase is regulated in the context of nuclear architecture. Here, we show that the catalytically active holoenzyme is initially assembled in the dense fibrillar component of the nucleolus during S phase. The telomerase RNP is retained in nucleoli through the interaction of hTERT with nucleolin, a major nucleolar phosphoprotein. Upon association with TCAB1 in S phase, the telomerase RNP is transported from nucleoli to Cajal bodies, suggesting that TCAB1 acts as an S-phase-specific holoenzyme component. Furthermore, depletion of TCAB1 caused an increase in the amount of telomerase RNP associated with nucleolin. These results suggest that the TCAB1-dependent trafficking of telomerase to Cajal bodies occurs in a step separate from the holoenzyme assembly in nucleoli. Thus, we propose that the dense fibrillar component is the provider of active telomerase RNP for supporting the continued proliferation of cancer and stem cells.

  6. The Cajal body and the nucleolus: "In a relationship" or "It's complicated"?

    Science.gov (United States)

    Trinkle-Mulcahy, Laura; Sleeman, Judith E

    2016-09-23

    From their initial identification as 'nucleolar accessory bodies' more than a century ago, the relationship between Cajal bodies and nucleoli has been a subject of interest and controversy. In this review, we seek to place recent developments in the understanding of the physical and functional relationships between the 2 structures in the context of historical observations. Biophysical models of nuclear body formation, the molecular nature of CB/nucleolus interactions and the increasing list of joint roles for CBs and nucleoli, predominantly in assembling ribonucleoprotein (RNP) complexes, are discussed.

  7. Cohesin and the nucleolus constrain the mobility of spontaneous repair foci.

    Science.gov (United States)

    Dion, Vincent; Kalck, Véronique; Seeber, Andrew; Schleker, Thomas; Gasser, Susan M

    2013-11-01

    The regulation of chromatin mobility in response to DNA damage is important for homologous recombination in yeast. Anchorage reduces rates of recombination, whereas increased chromatin mobility correlates with more efficient homology search. Here we tracked the mobility and localization of spontaneous S-phase lesions bound by Rad52, and find that these foci have reduced movement, unlike enzymatically induced double-strand breaks. Moreover, spontaneous repair foci are positioned in the nuclear core, abutting the nucleolus. We show that cohesin and nucleolar integrity constrain the mobility of these foci, consistent with the notion that spontaneous, S-phase damage is preferentially repaired from the sister chromatid.

  8. Occurrence of multiple nucleolus organizer regions and intraspecific karyotype variation in Scaptotrigona xanthotricha Moure (Hymenoptera, Meliponini).

    Science.gov (United States)

    Duarte, O M P; Martins, C C C; Waldschmidt, A M; Costa, M A

    2009-07-21

    Scaptotrigona xanthotricha has a wide geographic distribution in the Brazilian Atlantic rainforest. One population from southeast and two from northeast Brazil were analyzed and were found to have chromosome polymorphisms. Although the chromosome number 2n = 34 is conserved in this species, karyotypic analysis revealed clear differences between the three populations. Congruent and ubiquitous multiple nucleolus organizer regions, heterochromatin and CMA(3)-positive blocks were found. The variations suggest that this species is in a process of genetic differentiation. This differentiation process might have been enhanced by restricted nesting preferences, combined with recent extensive fragmentation of the Atlantic rainforest, which limits gene flow between populations.

  9. A new level set model for cell image segmentation

    Science.gov (United States)

    Ma, Jing-Feng; Hou, Kai; Bao, Shang-Lian; Chen, Chun

    2011-02-01

    In this paper we first determine three phases of cell images: background, cytoplasm and nucleolus according to the general physical characteristics of cell images, and then develop a variational model, based on these characteristics, to segment nucleolus and cytoplasm from their relatively complicated backgrounds. In the meantime, the preprocessing obtained information of cell images using the OTSU algorithm is used to initialize the level set function in the model, which can speed up the segmentation and present satisfactory results in cell image processing.

  10. A new level set model for cell image segmentation

    Institute of Scientific and Technical Information of China (English)

    Ma Jing-Feng; Hou Kai; Bao Shang-Lian; Chen Chun

    2011-01-01

    In this paper we first determine three phases of cell images: background, cytoplasm and nucleolus according to the general physical characteristics of cell images, and then develop a variational model, based on these characteristics, to segment nucleolus and cytoplasm from their relatively complicated backgrounds. In the meantime, the preprocessing obtained information of cell images using the OTSU algorithm is used to initialize the level set function in the model, which can speed up the segmentation and present satisfactory results in cell image processing.

  11. 凸模糊合作对策的模糊核仁%Fuzzy nucleolus of convex fuzzy cooperative game

    Institute of Scientific and Technical Information of China (English)

    樊梦欣; 高作峰; 韩佼佼; 闫莉; 邹正兴; 马栋

    2012-01-01

    The core is usually an empty set in simple games. In order to overcome this defect, this paper is to study the fuzzy nucleolus in fuzzy cooperative game. The nucleolus is an important solution of cooperative game. By extending the nucleolus model of cooperative game into fuzzy game, and defining the lexicographic order of fuzzy game, this paper provides the concept of fuzzy nucleolus in fuzzy cooperative game. Furthermore, the nucleolus properties of convex fuzzy cooperative game, such as its existence and uniqueness, are discussed and proved. The study demonstrates that the fuzzy nucleolus of fuzzy cooperative game is a natural continuation of cooperative game nucleolus. This result not only enriches the solution of fuzzy cooperative game, but also provides a structural solution of convex fuzzy cooperative game.%为了弥补在简单对策中核心具有常常为空的缺陷,研究模糊合作对策的模糊核仁解.核仁是合作对策的一种重要的解的形式.通过把合作对策核仁解的模型延拓到模糊对策中,并通过定义模糊合作对策的字典序,给出了模糊合作对策的模糊核仁的概念;然后进一步探讨了凸模糊合作对策的模糊核仁非空且唯一等特征和性质,并对此加以证明.研究表明:模糊合作对策的核仁是合作对策核仁的自然延拓.该结果丰富了对模糊合作对策的解的研究,从而解决了凸模糊合作对策的解的结构问题.

  12. HIV-1 nucleocapsid protein localizes efficiently to the nucleus and nucleolus

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Kyung Lee; Lee, Sun Hee; Lee, Eun Soo; You, Ji Chang, E-mail: jiyou@catholic.ac.kr

    2016-05-15

    The HIV-1 nucleocapsid (NC) is an essential viral protein containing two highly conserved retroviral-type zinc finger (ZF) motifs, which functions in multiple stages of the HIV-1 life cycle. Although a number of functions for NC either in its mature form or as a domain of Gag have been revealed, little is known about the intracellular localization of NC and, moreover, its role in Gag protein trafficking. Here, we have investigated various forms of HIV-1 NC protein for its cellular localization and found that the NC has a strong nuclear and nucleolar localization activity. The linker region, composed of a stretch of basic amino acids between the two ZF motifs, was necessary and sufficient for the activity. - Highlights: • HIV-1 NC possess a NLS and leads to nuclear and nucleolus localization. • Mutations in basic residues between two ZFs in NC decrease the nucleus localization. • ZFs of NC affect cytoplasmic organelles localization rather than nucleus localization.

  13. WRN translocation from nucleolus to nucleoplasm is regulated by SIRT1 and required for DNA repair and the development of chemoresistance.

    Science.gov (United States)

    Lee, Sun-Young; Lee, Hyunwoo; Kim, Eun-Sun; Park, Sojin; Lee, Jiyoen; Ahn, Byungchan

    2015-04-01

    When defective or absent, Werner syndrome protein (WRN) causes a genetic premature aging disorder called Werner syndrome. Several studies have reported that defects in WRN function are responsible for not only progeria syndrome but also genomic instability via the deregulation of DNA repair, replication, recombination, and telomere stability. Given the importance of WRN in the repair process, we herein investigated the potential role of WRN in drug response by evaluating the DNA repair following exposure to cisplatin in human cancer cell lines. We found that the down-regulation of SIRT1 and inhibition of SIRT1 deacetylase activity blocked the translocation of WRN from the nucleolus to the nucleoplasm in response to genotoxic stresses. In addition, cells expressing low levels of WRN responded favorably to cisplatin, whereas cells expressing high levels responded poorly to cisplatin. The forced expression of WRN protein in chemosensitive cells resulted in an approximately two-fold increase in cell viability in response to cisplatin compared with vector controls and promoted DNA repair, while WRN-deficient cells accumulate unrepaired double-strand breaks following cisplatin exposure. These results suggest that WRN is regulated by SIRT1 and increased expression of WRN might be one of the determinants for the development of chemotherapeutic drug resistance.

  14. Role of Cajal bodies and nucleolus in the maturation of the U1 snRNP in Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Zdravko J Lorković

    Full Text Available BACKGROUND: The biogenesis of spliceosomal snRNPs takes place in both the cytoplasm where Sm core proteins are added and snRNAs are modified at the 5' and 3' termini and in the nucleus where snRNP-specific proteins associate. U1 snRNP consists of U1 snRNA, seven Sm proteins and three snRNP-specific proteins, U1-70K, U1A, and U1C. It has been shown previously that after import to the nucleus U2 and U4/U6 snRNP-specific proteins first appear in Cajal bodies (CB and then in splicing speckles. In addition, in cells grown under normal conditions U2, U4, U5, and U6 snRNAs/snRNPs are abundant in CBs. Therefore, it has been proposed that the final assembly of these spliceosomal snRNPs takes place in this nuclear compartment. In contrast, U1 snRNA in both animal and plant cells has rarely been found in this nuclear compartment. METHODOLOGY/PRINCIPAL FINDINGS: Here, we analysed the subnuclear distribution of Arabidopsis U1 snRNP-specific proteins fused to GFP or mRFP in transiently transformed Arabidopsis protoplasts. Irrespective of the tag used, U1-70K was exclusively found in the nucleus, whereas U1A and U1C were equally distributed between the nucleus and the cytoplasm. In the nucleus all three proteins localised to CBs and nucleoli although to different extent. Interestingly, we also found that the appearance of the three proteins in nuclear speckles differ significantly. U1-70K was mostly found in speckles whereas U1A and U1C in approximately 90% of cells showed diffuse nucleoplasmic in combination with CBs and nucleolar localisation. CONCLUSIONS/SIGNIFICANCE: Our data indicate that CBs and nucleolus are involved in the maturation of U1 snRNP. Differences in nuclear accumulation and distribution between U1-70K and U1A and U1C proteins may indicate that either U1-70K or U1A and U1C associate with, or is/are involved, in other nuclear processes apart from pre-mRNA splicing.

  15. De-repression of RaRF-mediated RAR repression by adenovirus E1A in the nucleolus.

    Science.gov (United States)

    Um, Soo-Jong; Youn, Hye Sook; Kim, Eun-Joo

    2014-02-21

    Transcriptional activity of the retinoic acid receptor (RAR) is regulated by diverse binding partners, including classical corepressors and coactivators, in response to its ligand retinoic acid (RA). Recently, we identified a novel corepressor of RAR called the retinoic acid resistance factor (RaRF) (manuscript submitted). Here, we report how adenovirus E1A stimulates RAR activity by associating with RaRF. Based on immunoprecipitation (IP) assays, E1A interacts with RaRF through the conserved region 2 (CR2), which is also responsible for pRb binding. The first coiled-coil domain of RaRF was sufficient for this interaction. An in vitro glutathione-S-transferase (GST) pull-down assay was used to confirm the direct interaction between E1A and RaRF. Further fluorescence microscopy indicated that E1A and RaRF were located in the nucleoplasm and nucleolus, respectively. However, RaRF overexpression promoted nucleolar translocation of E1A from the nucleoplasm. Both the RA-dependent interaction of RAR with RaRF and RAR translocation to the nucleolus were disrupted by E1A. RaRF-mediated RAR repression was impaired by wild-type E1A, but not by the RaRF binding-defective E1A mutant. Taken together, our data suggest that E1A is sequestered to the nucleolus by RaRF through a specific interaction, thereby leaving RAR in the nucleoplasm for transcriptional activation.

  16. Deubiquitinating c-Myc: USP36 steps up in the nucleolus.

    Science.gov (United States)

    Sun, Xiao-Xin; Sears, Rosalie C; Dai, Mu-Shui

    2015-01-01

    Ubiquitination plays a key and complex role in the regulation of c-Myc stability, transactivation, and oncogenic activity. c-Myc is ubiquitinated by a number of ubiquitin ligases (E3s), such as SCF(Fbw7) and SCF(Skp2). Depending on the E3s, ubiquitination can either positively or negatively regulate c-Myc levels and activity. Meanwhile, c-Myc ubiquitination can be reversed by deubiquitination. An early study showed that USP28 deubiquitinates c-Myc via interacting with Fbw7α whereas a recent study reveals that USP37 deubiquitinates c-Myc independently of Fbw7 and c-Myc phosphorylation. Consequently, both USP28 and USP37 stabilize c-Myc and enhance its activity. We recently found the nucleolar USP36 as a novel c-Myc deubiquitinase that controls the end-point of c-Myc degradation pathway in the nucleolus. Here we briefly review the current understanding of ubiquitination and deubiquitination regulation of c-Myc and further discuss the USP36-c-Myc regulatory pathway.

  17. Relative Nucleolus of Flow Game on Simple Network%简单网络流对策的相对N-核

    Institute of Scientific and Technical Information of China (English)

    方奇志; 闫林成; 李晖

    2011-01-01

    This paper focuses on the relative nucleolus of the flow game defined on a simple network. When the value of the maximum flow in the network is l, the relative nucleolus coincides with the core. On the other hand, when the value of the maximum flow in the network is greater than 1, the relative nucleolus coincides with the original nucleolus. The main techniques in our proofs are Kopelowitz's sequential linear programming method and linear programming duality theorem. These results yield that the relative nucleolus of a simple flow game can be computed in polynomial time.%主要研究简单网络流对策中相对N-核的算法.当网络中最大流值等于1时,证明相对N-核与对策的核心相同,不一定是单点集;而当网络中最大流值大于1时,利用Kopelowitz's序列线性规划方法和线性规划对偶理论,证明相对N-核与N-核相同(同为单点集),并且可在局中人个数的多项式时间内得到求解.

  18. CRM1 and its ribosome export adaptor NMD3 localize to the nucleolus and affect rRNA synthesis.

    Science.gov (United States)

    Bai, Baoyan; Moore, Henna M; Laiho, Marikki

    2013-01-01

    CRM1 is an export factor that together with its adaptor NMD3 transports numerous cargo molecules from the nucleus to cytoplasm through the nuclear pore. Previous studies have suggested that CRM1 and NMD3 are detected in the nucleolus. However, their localization with subnucleolar domains or participation in the activities of the nucleolus are unclear. We demonstrate here biochemically and using imaging analyses that CRM1 and NMD3 co-localize with nucleolar marker proteins in the nucleolus. In particular, their nucleolar localization is markedly increased by inhibition of RNA polymerase I (Pol I) transcription by actinomycin D or by silencing Pol I catalytic subunit, RPA194. We show that CRM1 nucleolar localization is dependent on its activity and the expression of NMD3, whereas NMD3 nucleolar localization is independent of CRM1. This suggests that NMD3 provides nucleolar tethering of CRM1. While inhibition of CRM1 by leptomycin B inhibited processing of 28S ribosomal (r) RNA, depletion of NMD3 did not, suggesting that their effects on 28S rRNA processing are distinct. Markedly, depletion of NMD3 and inhibition of CRM1 reduced the rate of pre-47S rRNA synthesis. However, their inactivation did not lead to nucleolar disintegration, a hallmark of Pol I transcription stress, suggesting that they do not directly regulate transcription. These results indicate that CRM1 and NMD3 have complex functions in pathways that couple rRNA synthetic and processing engines and that the rRNA synthesis rate may be adjusted according to proficiency in rRNA processing and export.

  19. Nucleolus for repeated fuzzy cooperative games%重复模糊合作对策的核仁

    Institute of Scientific and Technical Information of China (English)

    韩佼佼; 高作峰; 闫莉; 樊梦欣; 马栋

    2013-01-01

      针对重复模糊合作对策中的解。将重复对策的模型引入到模糊对策中,以模糊结盟为工具建立了重复模糊合作对策的模型,在此基础上推广了模糊超出值的定义,对重复模糊合作对策的核仁进行了定义,给出了重复模糊合作对策核仁的一些性质。该成果使重复模糊合作对策更加完善。%In terms of the solutions of repeated fuzzy cooperative games, this study introduces the model of repeated cooperative game into the fuzzy game. The model of repeated fuzzy cooperative games has been developed based on fuzzy coalition. On the basis of above work, the concept of excess was extended. In addition, the concept of the nucleolus for repeated fuzzy cooperative games is proposed. Also, the properties of the nucleolus for repeated cooperative games are obtained. The study results improve the repeated fuzzy cooperative games.

  20. Colocalization of coilin and nucleolar proteins in Cajal body-like structures of micronucleated PtK2 cells

    Directory of Open Access Journals (Sweden)

    N.P. Silva

    2004-07-01

    Full Text Available Cajal bodies (CB are ubiquitous nuclear structures involved in the biogenesis of small nuclear ribonucleoproteins and show narrow association with the nucleolus. To identify possible relationships between CB and the nucleolus, the localization of coilin, a marker of CB, and of a set of nucleolar proteins was investigated in cultured PtK2 cells undergoing micronucleation. Nocodazol-induced micronucleated cells were examined by double indirect immunofluorescence with antibodies against coilin, fibrillarin, NOR-90/hUBF, RNA polymerase I, PM/Scl, and To/Th. Cells were imaged on a BioRad 1024-UV confocal system attached to a Zeiss Axiovert 100 microscope. Since PtK2 cells possess only one nucleolus organizer region, micronucleated cells presented only one or two micronuclei containing nucleolus. By confocal microscopy we showed that in most micronuclei lacking a typical nucleolus a variable number of round structures were stained by antibodies against fibrillarin, NOR-90/hUBF protein, and coilin. These bodies were regarded as CB-like structures and were not stained by anti-PM/Scl and anti-To/Th antibodies. Anti-RNA polymerase I antibodies also reacted with CB-like structures in some micronuclei lacking nucleolus. The demonstration that a set of proteins involved in RNA/RNP biogenesis, namely coilin, fibrillarin, NOR-90/hUBF, and RNA polymerase I gather in CB-like structures present in nucleoli-devoid micronuclei may contribute to shed some light into the understanding of CB function.

  1. Nucleolus disassembly in mitosis and apoptosis: dynamic redistribution of phosphorylated-c-Myc, fibrillarin and Ki-67

    Directory of Open Access Journals (Sweden)

    C Soldani

    2009-06-01

    Full Text Available The nucleolus may undergo disassembly either reversibly during mitosis, or irreversibly in apoptosis, thus allowing the redistribution of the nucleolar proteins.We investigated here by immunocytochemistry the fate of three representative proteins, namely phosphorylated c-Myc, fibrillarin and Ki-67, and found that they behave independently in both processes: they relocate in distinct compartments during mitosis, whereas during apoptosis they may either be cleaved (Ki-67 or be extruded into the cytoplasm with a different kinetics and following an ordered, non chaotic program. The separation of these nucleolar proteins which occurs in early apoptotic nuclei continues also in the cytoplasm, and culminates in the final formation of apoptotic blebs containing different nucleolar proteins: this evidence confirms that the apoptotic bodies may be variable in size, content and surface reactivity, and include heterogeneous aggregates of nuclear proteins and/or nucleic acids.

  2. Cell fate in the hand of Plk4

    NARCIS (Netherlands)

    Tanenbaum, Marvin E.; Medema, Rene H.

    2007-01-01

    The transcription factor Hand1 is required for cell-fate determination during placental development. Recent work shows that release of Hand1 from the nucleolus controls differentiation of trophoblast stem cells into trophoblast giant cells, and this switch is controlled by the antagonistic activitie

  3. Nucleolar localization of influenza A NS1: striking differences between mammalian and avian cells

    Directory of Open Access Journals (Sweden)

    Mazel-Sanchez Beryl

    2010-03-01

    Full Text Available Abstract In mammalian cells, nucleolar localization of influenza A NS1 requires the presence of a C-terminal nucleolar localization signal. This nucleolar localization signal is present only in certain strains of influenza A viruses. Therefore, only certain NS1 accumulate in the nucleolus of mammalian cells. In contrast, we show that all NS1 tested in this study accumulated in the nucleolus of avian cells even in the absence of the above described C-terminal nucleolar localization signal. Thus, nucleolar localization of NS1 in avian cells appears to rely on a different nucleolar localization signal that is more conserved among influenza virus strains.

  4. 直觉模糊支付合作对策的核仁解%Nucleolus of Intuitionistic Fuzzy Payoffs Cooperative Game

    Institute of Scientific and Technical Information of China (English)

    郭菊花; 高作峰

    2014-01-01

    本文主要研究支付值为直觉模糊集的合作对策问题及其模糊核仁解。首先定义了直觉模糊集的得分函数和精确函数,并给出其排序方法,得到基于直觉模糊集的合作对策模型和适合这种模型的相应定义,同时提出了直觉模糊核仁解的概念;其次运用新的排序方法将求核仁解的问题转化为求解双目标非线性规划问题;最后通过实例分析验证了该方法的可行性和有效性。%This paper focuses on the problem of the cooperative game with payoffs of intuitionistic fuzzy sets ( IFS) and its fuzzy nucleolus .Firstly, the score function and accurate function of IFS are defined and given their the approach for ranking of IFS .The cooperative game model and its related definitions are given .The concept of the fuzzy nucleolus in fuzzy cooperative game is put forward .Secondly , according to the new ranking approach , the intuitionistic fuzzy nucleolus can be obtained by solving the bi-objective nonlinear programming model .Finally, an example is given to explain the feasibility and availability of this method .

  5. 苏铁(Cycasrevoluta)种子核仁中氨基酸成分分析%Analysis on nucleolus amino acid composition of Cycas revoluta seeds

    Institute of Scientific and Technical Information of China (English)

    黄超群; 莫昭展

    2013-01-01

    In this paper, the amino acids in nucleolus of Cycas revolute were analyzed. There were 17 types of amino acids in nucleolus. According to the analysis results, proportions of Total Amino Acid(TAA) and Essential Amino Acid(EAA) were respectively 8.16% and 2.91%, which was smaller than proportion of standard protein. However, Amino acids for medical purposes and flavor amino acid accounted separately for 68% and 27.7% of TAA, which had important significance for development and utilization of Cycas revolute seeds.%对苏铁种子核仁中氨基酸成分进行分析,苏铁种子中含有17种氨基酸,其中总氨基酸(TAA)和必需氨基酸(EAA)含量分别为8.16和2.91.其两种氨基酸的比例与标准蛋白质存在一定的差距,但是苏铁种子药用氨基酸和鲜味氨基酸的含量分别为68%和27.7%,对苏铁种子的开发利用具有重要意义.

  6. Rrp12 and the Exportin Crm1 participate in late assembly events in the nucleolus during 40S ribosomal subunit biogenesis.

    Science.gov (United States)

    Moriggi, Giulia; Nieto, Blanca; Dosil, Mercedes

    2014-12-01

    During the biogenesis of small ribosomal subunits in eukaryotes, the pre-40S particles formed in the nucleolus are rapidly transported to the cytoplasm. The mechanisms underlying the nuclear export of these particles and its coordination with other biogenesis steps are mostly unknown. Here we show that yeast Rrp12 is required for the exit of pre-40S particles to the cytoplasm and for proper maturation dynamics of upstream 90S pre-ribosomes. Due to this, in vivo elimination of Rrp12 leads to an accumulation of nucleoplasmic 90S to pre-40S transitional particles, abnormal 35S pre-rRNA processing, delayed elimination of processing byproducts, and no export of intermediate pre-40S complexes. The exportin Crm1 is also required for the same pre-ribosome maturation events that involve Rrp12. Thus, in addition to their implication in nuclear export, Rrp12 and Crm1 participate in earlier biosynthetic steps that take place in the nucleolus. Our results indicate that, in the 40S subunit synthesis pathway, the completion of early pre-40S particle assembly, the initiation of byproduct degradation and the priming for nuclear export occur in an integrated manner in late 90S pre-ribosomes.

  7. 一个可指示核仁定位和柯浩体定位信号Marker的构建%Construction and Application of A Marker Localizing in Nucleolus and Cajal Body

    Institute of Scientific and Technical Information of China (English)

    郑璐平; 毛倩卓; 林辰; 谢荔岩; 吴祖建; 谢联辉

    2013-01-01

    通过RT-PCR获得本氏烟纤维蛋白Fibrillarin2的cDNA,并将其重组到表达载体pEarley 101(黄色荧光蛋白,YFP)和pEarley 102(青色荧光蛋白,CFP)上.在本氏烟叶片表皮细胞中瞬时表达融合蛋白,激光共聚焦显微镜下观察,发现蛋白定位在细胞核仁和柯浩体上,可以作为这两种细胞器的指示Marker,并通过Western blot检测融合蛋白的表达.该Marker对明确蛋白特别是病毒编码的蛋白在细胞核中的定位以及功能推测具有重要意义.%cDNA encoding Nicotiana benthamiana fibrillarin2 was amplified by RT-PCR and inserted into expressed vectors which include YFP or CFP.Transient expression of these constructs was on leaf epidermal cells ofNicotiana benthamiana,these proteins localized in the nucleolus and cajal body,which can be a marker of these two organelles.The expression of these new fusion proteins were also verified by Western blot.This marker maybe play a role on indicating accurate localization in nucleus and forecasting the function of proteins,especially virusencoded proteins.

  8. C. elegans nucleostemin is required for larval growth and germline stem cell division.

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    Michelle M Kudron

    Full Text Available The nucleolus has shown to be integral for many processes related to cell growth and proliferation. Stem cells in particular are likely to depend upon nucleolus-based processes to remain in a proliferative state. A highly conserved nucleolar factor named nucleostemin is proposed to be a critical link between nucleolar function and stem-cell-specific processes. Currently, it is unclear whether nucleostemin modulates proliferation by affecting ribosome biogenesis or by another nucleolus-based activity that is specific to stem cells and/or highly proliferating cells. Here, we investigate nucleostemin (nst-1 in the nematode C. elegans, which enables us to examine nst-1 function during both proliferation and differentiation in vivo. Like mammalian nucleostemin, the NST-1 protein is localized to the nucleolus and the nucleoplasm; however, its expression is found in both differentiated and proliferating cells. Global loss of C. elegans nucleostemin (nst-1 leads to a larval arrest phenotype due to a growth defect in the soma, while loss of nst-1 specifically in the germ line causes germline stem cells to undergo a cell cycle arrest. nst-1 mutants exhibit reduced levels of rRNAs, suggesting defects in ribosome biogenesis. However, NST-1 is generally not present in regions of the nucleolus where rRNA transcription and processing occurs, so this reduction is likely secondary to a different defect in ribosome biogenesis. Transgenic studies indicate that NST-1 requires its N-terminal domain for stable expression and both its G1 GTPase and intermediate domains for proper germ line function. Our data support a role for C. elegans nucleostemin in cell growth and proliferation by promoting ribosome biogenesis.

  9. Cajal body number and nucleolar size correlate with the cell body mass in human sensory ganglia neurons.

    Science.gov (United States)

    Berciano, Maria T; Novell, Mariona; Villagra, Nuria T; Casafont, Iñigo; Bengoechea, Rocio; Val-Bernal, J Fernado; Lafarga, Miguel

    2007-06-01

    This paper studies the cell size-dependent organization of the nucleolus and Cajal bodies (CBs) in dissociated human dorsal root ganglia (DRG) neurons from autopsy tissue samples of patients without neurological disease. The quantitative analysis of nucleoli with an anti-fibrillarin antibody showed that all neurons have only one nucleolus. However, the nucleolar volume and the number of fibrillar centers per nucleolus significantly increase as a function of cell body size. Immunostaining for coilin demonstrated the presence of numerous CBs in DRG neurons (up to 20 in large size neurons). The number of CBs per neuron correlated positively with the cell body volume. Light and electron microscopy immunocytochemical analysis revealed the concentration of coilin, snRNPs, SMN and fibrillarin in CBs of DRG neurons. CBs were frequently associated with the nucleolus, active chromatin domains and PML bodies, but not with telomeres. Our results support the view that the nucleolar volume and number of both fibrillar centers and CBs depend on the cell body mass, a parameter closely related to transcriptional and synaptic activity in mammalian neurons. Moreover, the unusual large number of CBs could facilitate the transfer of RNA processing components from CBs to nucleolar and nucleoplasmic sites of RNA processing.

  10. 高负压劈核技术在硬核白内障复明手术中的效果观察%Effect of High Vacuum Phaco Chop Technique for Hard Nucleolus Cataract

    Institute of Scientific and Technical Information of China (English)

    卢建民

    2011-01-01

    Objective To observe the effect of high vacuum phaco chop technique for hard nucleolus cataract. Methods 51 cases (65 eyes) of hard nucleolus cataract were performed by high vacuum phaco chop. Results The best corrected visual acuity (BCVA) ≥ 0. 3 was in 56 eyes (86%) one day after operation. The best corrected visual acuity (BCVA) ≥ 0.3 was in 61 eyes (94%) one month after operation. 3 eyes had posterior capsule rupture in operation. Conclusion High vacuum phaco chop technique is safe and effective for hard nucleolus cataract.%目的观察高负压劈核技术在硬核白内障手术的效果.方法采用高负压下劈核技术对51例65眼硬核白内障进行超声乳化手术.结果术后1 d矫正视力≥0.3者56眼(86%),术后1个月矫正视力≥0.3者61眼(94%),后囊膜破裂3例.结论高负压劈核技术对硬核白内障具有安全高效的复明效果.

  11. Elucidation of the avian nucleolar proteome by quantitative proteomics using SILAC and changes in cells infected with the coronavirus infectious bronchitis virus.

    Science.gov (United States)

    Emmott, Edward; Smith, Catriona; Emmett, Stevan R; Dove, Brian K; Hiscox, Julian A

    2010-10-01

    The nucleolus is a dynamic subnuclear compartment involved in ribosome subunit biogenesis, regulation of cell stress and modulation of cellular growth and the cell cycle, among other functions. The nucleolus is composed of complex protein/protein and protein/RNA interactions. It is a target of virus infection with many viral proteins being shown to localize to the nucleolus during infection. Perturbations to the structure of the nucleolus and its proteome have been predicted to play a role in both cellular and infectious disease. Stable isotope labeling with amino acids in cell culture coupled to LC-MS/MS with bioinformatic analysis using Ingenuity Pathway Analysis was used to investigate whether the nucleolar proteome altered in virus-infected cells. In this study, the avian nucleolar proteome was defined in the absence and presence of virus, in this case the positive strand RNA virus, avian coronavirus infectious bronchitis virus. Data sets, potential protein changes and the functional consequences of virus infection were validated using independent assays. These demonstrated that specific rather than generic changes occurred in the nucleolar proteome in infectious bronchitis virus-infected cells.

  12. S1 Nuclease Sensitivity of Surrounded Nucleolus(SN)- and Non Surrounded Nucleolus(NSN)-type Mouse Ooctyes during In vitro Maturation%小鼠SN和NSN卵成熟分裂过程中S1核酸酶敏感性变化

    Institute of Scientific and Technical Information of China (English)

    李俊; 杨明升; 李迎香; 徐银学; 刘红林

    2004-01-01

    比较了两种染色质构型不同的小鼠卵泡卵子体外成熟过程中S1核酸酶敏感性的变化.结果发现,染色质构型不同的两类小鼠卵子在第1次减数分裂中期(MⅠ期)S1核酸酶的敏感性存在显著差异,NSN(non-surrounded nucleolus,染色质结构较松散,散布在核质中)型卵子S1核酸酶的敏感性显著高于SN(surrounded nucleolus,染色质高度凝集,集中围绕在核仁周围,形成染色质环)型卵子(P<0.01);然而在第2次减数分裂中期(MⅡ期)两种类型卵子S1核酸酶的敏感性趋于一致,二者无显著差异(P>0.05).染色质构型不同的两种卵子发育至M Ⅰ期时,染色体单链构型丰富度存在显著差异,但由M Ⅰ期发育到MⅡ期过程中,二者单链构型丰富度趋于一致.

  13. Characterization of a novel mouse gene encoding an SYCP3-like protein that relocalizes from the XY body to the nucleolus during prophase of male meiosis I.

    Science.gov (United States)

    Tsutsumi, Makiko; Kogo, Hiroshi; Kowa-Sugiyama, Hiroe; Inagaki, Hidehito; Ohye, Tamae; Kurahashi, Hiroki

    2011-07-01

    Xlr6 is a novel but uncharacterized X-linked gene that is upregulated in meiotic prophase I during mouse spermatogenesis. Xlr6 belongs to the Xlr gene family, which includes a component of the axial/lateral element of the synaptonemal complex, Sycp3, and its transcripts are abundant in the fetal ovary and adult testis. Immunostaining and Western blot analysis demonstrate a diffuse localization pattern for this protein in the nucleus and an association with chromatin during the leptotene and zygotene stages. In males, XLR6 accumulates at the XY body of early pachytene to midpachytene spermatocytes, although the Xlr6 gene is subjected to meiotic sex chromosome inactivation. During the late pachytene and diplotene stages, the XLR6 protein relocalizes from the XY body to the nucleolus and, eventually, disappears by diakinesis. In females, XLR6 disappears at the pachytene stage, whereas it accumulates at the unpaired chromosomes occasionally observed in wild-type female mice. Although the amino acid sequence of XLR6 has a high similarity with SYCP3, its distinct localization pattern and dynamism suggest a unique chromatin modification function that leads to the transcriptional repression of ribosomal DNA in addition to sex chromosome genes.

  14. Polymorphisms of the nucleolus organizing regions in Loricaria cataphracta (Siluriformes, Loricariidae) of the upper Paraguay River basin indicate an association with transposable elements.

    Science.gov (United States)

    Porto, F E; Gindri, B S; Vieira, M M R; Borin, L A; Portela-Castro, A L B; Martins-Santos, I C

    2014-03-12

    A cytogenetic analysis of Loricaria cataphracta revealed a diploid number of 2n = 64 chromosomes, distributed as 12 metacentric + 8 submetacentric + 2 subtelocentric + 42 acrocentric, with a fundamental number of 86. Analysis of the nucleolus organizing region (NOR) using silver nitrate impregnation and fluorescence in situ hybridization (18S rDNA probe) techniques showed intra-population chromosomal polymorphism that could be classified into five different patterns (I to V), involving four pairs of chromosomes (8, 9, 12, and 13). In pattern I, the NOR was located in pair 12, whereas in pattern II, the NOR was detected in pair 8; these two patterns were characterized as a simple-NOR system. A multiple NOR system was evident in the other patterns (III, IV, and V). In pattern III, the NOR was located in only one of the homologs of pairs 12 and 8, and in patterns IV and V, the NOR was observed in pair 12 and in only one of the homologs of pairs 9 and 13, respectively. In addition, C-band analysis also showed this pattern of variation, and characterized a polymorphism in relation to the constitutive heterochromatin; the composition of this region was GC-rich (positive CMA3) and 4',6-diamidino-2-phenylindole negative. Transposition of NOR sites for mobile elements is suggested to explain this polymorphism.

  15. Alanine zipper-like coiled-coil domains are necessary for homotypic dimerization of plant GAGA-factors in the nucleus and nucleolus.

    Directory of Open Access Journals (Sweden)

    Dierk Wanke

    Full Text Available GAGA-motif binding proteins control transcriptional activation or repression of homeotic genes. Interestingly, there are no sequence similarities between animal and plant proteins. Plant BBR/BPC-proteins can be classified into two distinct groups: Previous studies have elaborated on group I members only and so little is known about group II proteins. Here, we focused on the initial characterization of AtBPC6, a group II protein from Arabidopsis thaliana. Comparison of orthologous BBR/BPC sequences disclosed two conserved signatures besides the DNA binding domain. A first peptide signature is essential and sufficient to target AtBPC6-GFP to the nucleus and nucleolus. A second domain is predicted to form a zipper-like coiled-coil structure. This novel type of domain is similar to Leucine zippers, but contains invariant alanine residues with a heptad spacing of 7 amino acids. By yeast-2-hybrid and BiFC-assays we could show that this Alanine zipper domain is essential for homotypic dimerization of group II proteins in vivo. Interhelical salt bridges and charge-stabilized hydrogen bonds between acidic and basic residues of the two monomers are predicted to form an interaction domain, which does not follow the classical knobs-into-holes zipper model. FRET-FLIM analysis of GFP/RFP-hybrid fusion proteins validates the formation of parallel dimers in planta. Sequence comparison uncovered that this type of domain is not restricted to BBR/BPC proteins, but is found in all kingdoms.

  16. Nucleolus-like bodies of fully-grown mouse oocytes contain key nucleolar proteins but are impoverished for rRNA.

    Science.gov (United States)

    Shishova, Kseniya V; Lavrentyeva, Elena A; Dobrucki, Jurek W; Zatsepina, Olga V

    2015-01-15

    It is well known that fully-grown mammalian oocytes, rather than typical nucleoli, contain prominent but structurally homogenous bodies called "nucleolus-like bodies" (NLBs). NLBs accumulate a vast amount of material, but their biochemical composition and functions remain uncertain. To clarify the composition of the NLB material in mouse GV oocytes, we devised an assay to detect internal oocyte proteins with fluorescein-5-isothiocyanate (FITC) and applied the fluorescent RNA-binding dye acridine orange to examine whether NLBs contain RNA. Our results unequivocally show that, similarly to typical nucleoli, proteins and RNA are major constituents of transcriptionally active (or non-surrounded) NLBs as well as of transcriptionally silent (or surrounded) NLBs. We also show, by exposing fixed oocytes to a mild proteinase K treatment, that the NLB mass in oocytes of both types contains nucleolar proteins that are involved in all major steps of ribosome biogenesis, including rDNA transcription (UBF), early rRNA processing (fibrillarin), and late rRNA processing (NPM1/nucleophosmin/B23, nucleolin/C23), but none of the nuclear proteins tested, including SC35, NOBOX, topoisomerase II beta, HP1α, and H3. The ribosomal RPL26 protein was detected within the NLBs of NSN-type oocytes but is virtually absent from NLBs of SN-type oocytes. Taking into account that the major class of nucleolar RNA is ribosomal RNA (rRNA), we applied fluorescence in situ hybridization with oligonucleotide probes targeting 18S and 28S rRNAs. The results show that, in contrast to active nucleoli, NLBs of fully-grown oocytes are impoverished for the rRNAs, which is consistent with the absence of transcribed ribosomal genes in the NLB mass. Overall, the results of this study suggest that NLBs of fully-grown mammalian oocytes serve for storing major nucleolar proteins but not rRNA.

  17. Utp22p acts in concert with Utp8p to channel aminoacyl-tRNA from the nucleolus to the nuclear tRNA export receptor Los1p but not Msn5p.

    Science.gov (United States)

    Eswara, Manoja B K; Clayton, Ashley; Mangroo, Dev

    2012-12-01

    Utp8p is an essential nucleolar protein that channels aminoacyl-tRNAs from aminoacyl-tRNA synthetases in the nucleolus to the nuclear tRNA export receptors located in the nucleoplasm and nuclear pore complex in Saccharomyces cerevisiae. Utp8p is also part of the U3 snoRNA-associated protein complex involved in 18S rRNA biogenesis in the nucleolus. We report that Utp22p, which is another member of the U3 snoRNA-associated protein complex, is also an intranuclear component of the nuclear tRNA export machinery. Depletion of Utp22p results in nuclear retention of mature tRNAs derived from intron-containing and intronless precursors. Moreover, Utp22p copurifies with the nuclear tRNA export receptor Los1p, the aminoacyl-tRNA synthetase Tys1p and Utp8p, but not with the RanGTPase Gsp1p and the nuclear tRNA export receptor Msn5p. Utp22p interacts directly with Utp8p and Los1p in a tRNA-independent manner in vitro. Utp22p also interacts directly with Tys1p, but this binding is stimulated when Tys1p is bound to tRNA. However, Utp22p, unlike Utp8p, does not bind tRNA saturably. These data suggest that Utp22p recruits Utp8p to aminoacyl-tRNA synthetases in the nucleolus to collect aminoacyl-tRNA and then accompanies the Utp8p-tRNA complex to deliver the aminoacyl-tRNAs to Los1p but not Msn5p. It is possible that Nrap/Nol6, the mammalian orthologue of Utp22p, plays a role in channelling aminoacyl-tRNA to the nuclear tRNA export receptor exportin-t.

  18. Electron microscopy of the germ cells and the ovarian wall in Xiphinema (Nematoda).

    Science.gov (United States)

    Van de Velde, M C; Coomans, A

    1988-01-01

    The ovary of Xiphinema theresiae is studied ultrastructurally. It consists of two cell types, the ovarian epithelial cells and the germ cells. The ovarian epithelial cells form a thin layer around the germ cells. Their nuclei are located in between the germ cells. At some sites, processes of the ovarian epithelial cells migrate inward and form a central cytoplasmic mass. The germ cells have a large lobated nucleus, with an eccentric nucleolus, and are considered to represent young previtellogenic oocytes. In contact with the central cytoplasmic mass, the germ cells develop two membrane derived features, the villi and the small coated bulges, which most probably play a role in transport.

  19. Arabidopsis HIT4, a regulator involved in heat-triggered reorganization of chromatin and release of transcriptional gene silencing, relocates from chromocenters to the nucleolus in response to heat stress.

    Science.gov (United States)

    Wang, Lian-Chin; Wu, Jia-Rong; Hsu, Yi-Ju; Wu, Shaw-Jye

    2015-01-01

    Arabidopsis HIT4 is known to mediate heat-induced decondensation of chromocenters and release from transcriptional gene silencing (TGS) with no change in the level of DNA methylation. It is unclear whether HIT4 and MOM1, a well-known DNA methylation-independent transcriptional silencer, have overlapping regulatory functions. A hit4-1/mom1 double mutant strain was generated. Its nuclear morphology and TGS state were compared with those of wild-type, hit4-1, and mom1 plants. Fluorescent protein tagging was employed to track the fates of HIT4, hit4-1 and MOM1 in vivo under heat stress. HIT4- and MOM1-mediated TGS were distinguishable. Both HIT4 and MOM1 were localized normally to chromocenters. Under heat stress, HIT4 relocated to the nucleolus, whereas MOM1 dispersed with the chromocenters. hit4-1 was able to relocate to the nucleolus under heat stress, but its relocation was insufficient to trigger the decompaction of chromocenters. The hypersensitivity to heat associated with the impaired reactivation of TGS in hit4-1 was not alleviated by mom1-induced release from TGS. HIT4 delineates a novel and MOM1-independent TGS regulation pathway. The involvement of a currently unidentified component that links HIT4 relocation and the large-scale reorganization of chromatin, and which is essential for heat tolerance in plants is hypothesized.

  20. Structural components of the nuclear body in nuclei of Allium cepa cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nuclear bodies have long been noted in interphase nuclei of plant cells,but their structural component,origin and function are still unclear by now.The present work showed in onion cells the nuclear bodies appeared as a spherical structure about 0.3 to 0.8 μm in diameter.They possibly were formed in nucleolus and subsequently released,and entered into nucleoplasm.Observation through cytochemical staining method at the ultrastructural level confirmed that nuclear bodies consisted of ribonucleoproteins (RNPs) and silver-stainable proteins.Immunocytochemical results revealed that nuclear bodies contained no DNA and ribosomal gene transcription factor (UBF).Based on these data,we suggested that nuclear bodies are not related to the ribosome or other gene transcription activities,instead they may act as subnuclear structures for RNPs transport from nucleolus to cytoplasm,and may also be involved in splicing of pre-mRNAs.

  1. MicroRaman Spectroscopy and Raman Imaging of Basal Cell Carcinoma

    Science.gov (United States)

    Short, M. A.; Zeng, H.; Lui, H.

    2005-03-01

    We have measured the Raman spectra of normal and cancerous skin tissues using a confocal microRaman spectrograph with a sub-micron spatial resolution. We found that the Raman spectrum of a cell nucleolus is different from the spectra measured outside the nucleolus and considerably different from those measured outside the nucleus. In addition, we found significant spectroscopic differences between normal and cancer-bearing sites in the dermis region. In order to utilize these differences for non-invasive skin cancer diagnosis, we have developed a Raman imaging system that clearly demonstrates the structure, location and distribution of cells in unstained skin biopsy samples. Our method is expected to be useful for the detection and characterization of skin cancer based on the known distinct cellular differences between normal and malignant skin.

  2. Altered subcellular distribution of nucleolar protein fibrillarin by actinomycin D in Hep-2 cells

    Institute of Scientific and Technical Information of China (English)

    Min CHEN; Ping JIANG

    2004-01-01

    AIM: To study the effects of actinomycin D on subcellular distribution of nucleolar protein fibrillarin in HEp-2(human esophageal epithelial type 2) cells, and molecular mechanisms for maintenance of fibrillarin in nucleolus.METHODS: Indirect immunofiuorescence assay was employed to investigate subcellular distribution of nucleolar protein fibrillarin and immunoblotting analysis was used to detect the total cellular amount of fibrillarin. RESULTS:Control cells with no drug treatment showed bright clumpy nucleolar staining, which indicated that fibrillarin decorated the nucleolus only. Treatment with actinomycin D caused dislocation of fibrillarin from nucleoli to nucleoplasm with numerous stained small nucleoplasmic entities. Immunoblotting showed that neither total cellular amount of fibrillarin nor the integrity of fibrillarin was changed upon the treatment. The dislocation of fibrillarin in cells treated at a lower concentration (0.05 mg/L) of actinomycin D, was totally reversible after removal of the drug from the medium. However, this reversion was not observed at a high drug concentration (1 mg/L). CONCLUSION:Actinomycin D induced dislocation of fibrillarin from nucleoli to nucleoplasm in HEp-2 cells. The retention of fibrillarin within the nucleolus was related to active RNA synthesis.

  3. Biomimetic fat cell (BFC) preparation and for lindane removal from aqueous solution.

    Science.gov (United States)

    Liyan, Song; Youcai, Zhao; Guojian, Wang; Bing, Li; Dongjie, Niu; Xiaoli, Chai

    2007-07-19

    Fat tissue of organism can accumulate hydrophobic chemicals efficiently and the accumulation level has a positive correlation with fat quantity. In this work, based on this characteristic, an innovative agent, that is, biomimetic fat cell (BFC) has been synthesized with interfacial polymerization. BFC has a hydrophobic nucleolus-triolein and hydrophilic membrane-polyamide, through which water, carrying hydrophobic organic contaminants (HOCs), can pass. This process is followed by the accumulation of HOCs. BFC has 97.39% lindane removal ability. This is close to 98.12% lindane removal by powder active carbon (PAC) in aqueous solution and 7 mg/L initial concentration of lindane. BFC can be regenerated easily by organic solvent dialysis in comparison with high temperature or pressure used for PAC regeneration. Lindane removal by BFC may occur through two mechanisms: bioaccumulation by BFC nucleolus-triolein; and adsorption by BFC membrane. Bioaccumulation is the prevailing mechanism.

  4. The development of fluorescence turn-on probe for Al(III) sensing and live cell nucleus-nucleoli staining

    Science.gov (United States)

    Saini, Anoop Kumar; Sharma, Vinay; Mathur, Pradeep; Shaikh, Mobin M.

    2016-01-01

    The morphology of nucleus and nucleolus is powerful indicator of physiological and pathological conditions. The specific staining of nucleolus recently gained much attention due to the limited and expensive availability of the only existing stain “SYTO RNA-Select”. Here, a new multifunctional salen type ligand (L1) and its Al3+ complex (1) are designed and synthesized. L1 acts as a chemosensor for Al3+ whereas 1 demonstrates specific staining of nucleus as well as nucleoli. The binding of 1 with nucleic acid is probed by DNase and RNase digestion in stained cells. 1 shows an excellent photostability, which is a limitation for existing nucleus stains during long term observations. 1 is assumed to be a potential candidate as an alternative to expensive commercial dyes for nucleus and nucleoli staining. PMID:27721431

  5. Ultrastructural Observations of the Vitelline Cells of Metamicrocotyla macracantha (Monogenea, Microcotylidae

    Directory of Open Access Journals (Sweden)

    Maria de Fatima D Baptista-Farias

    1998-07-01

    Full Text Available An electron microscopic study of the vitelline follicles of Metamicrocotyla macracantha (Alexander, 1954 Koratha,1955 showed that they are composed of cells in different stages of development. The immature cells have a large nucleus, nucleolus, cytoplasm with free ribosomes and few mitochondria. The developing vitelline cells present granules which are small in the early stages, increasing with maturity. The mature cells have an extensive granular endoplasmic reticulum and droplets of shell-protein; with maturation, clusters of shell protein and yolk bodies are formed and released in the ciliated vitelline ducts. Vitelline development is continuous and all of the cellular stages involved can be found in each follicle.

  6. 核糖体蛋白rpS6在核仁中的定位与其磷酸化无关%Location of Ribosomal Protein S6 in Higher Eukaryocyte Nucleolus not Related to Its Phosphorylation

    Institute of Scientific and Technical Information of China (English)

    张朵; 高丽华; 邵勇; 郗永义; 胥照平; 陈惠鹏; 胡显文

    2012-01-01

    核糖体蛋白S6(rpS6)是核糖体小亚基40S的一个组成成分.在该研究中,利用免疫荧光和邻位连接技术证明rpS6不仅是核糖体小亚基的组成成分,而且还可与核仁中的U3核蛋白复合体的标志性蛋白Mppl0共定位并且存在相互作用.rpS6蛋白的C端有5个丝氨酸磷酸化位点,为了研究rpS6蛋白在核仁中的分布是否与其磷酸化有关,构建了rpS6蛋白的两个突变体rpS6A和rpS6D分别与EGFP和HA的融合蛋白.rpS6A是将C端的5个丝氨酸位点全部突变为丙氨酸;rpS6D是将C端的5个丝氨酸位点全部突变为天冬氨酸.研究表明:rpS6、rpS6A和rpS6D与EGFP和HA的融合蛋白均可分布在核仁中,与内源性rpS6蛋白的分布情况一致,说明rpS6蛋白在核仁中的定位与其磷酸化无关,为探索rpS6蛋白在核仁中的功能奠定了良好的基础.%Ribosomal protein S6 (rpS6) was considered as a component of the cytosohc 40S ribosomalsubunit. However, using the technique of proximity ligation in situ assay and immunofluorescence analysis, the studies presented here revealed that rpS6 was not only a component of the 40S ribosomal subunit, but also colocal-ized and interacted with Mpp10, an essential component of U3 snoRNP. The rpS6 protein had five phosphorylation sites at the C terminus. In order to identify the relationship of distribution in nucleohis with,its phosphorylation, we constructed two mutations of rpS6. One was rpS6A whose five phosphorylatable serine residues sites were replaced by alanine residues, the other was rpS6D whose five phosphorylatable serine residues sites were replaced by aspartic acides. The rpS6, rpS6A and rpS6D protein were expressed as fusion with EGFP and HA tag, respectively. The results showed that not only rpS6 fusion protein but also rpS6A and rpS6D fusion protein could distribute in nucleolus, suggesting the phosphorylation could not affect rpS6 protein entering into nucleolus. This work made a way for the study of rpS6

  7. Subnucleolar Distribution and Transportation of U3 snoRNA in the Nucleolus of Pisum sativum%豌豆细胞核仁中U3 snoRNA的分布和转运

    Institute of Scientific and Technical Information of China (English)

    龙鸿; 曾宪录; 胡波; 孙海晶; 刘振兰; 郝水

    2003-01-01

    rRNA前体剪切是发生在核仁中的重要生物学事件.U3 snoRNA作为rRNA的一个剪切因子被认为是rRNA前体剪切第一步,即5′ ETS剪切所必需的.鉴定U3能够为确定rRNA前体剪切位点和剪切产物转运提供间接证据.本文利用原位杂交技术研究了豌豆(Pisum sativum L.)核仁中U3 snoRNA的分布和转运.结果表明, U3 snoRNA分布在致密纤维组分(dense fibrillar component, DFC)和颗粒组分(granular component, GC)中,在纤维中心(fibrillar center, FC)没有分布.当用放线菌素D (actinomycin D, AMD)处理豌豆根端分生细胞时,rDNA转录受到抑制,标记信号减弱.随着AMD处理时间的延长,标记信号逐渐变弱并出现在DFC远轴区域和GC区域.本文结果提示,rRNA前体剪切发生在DFC和GC区域,剪切产物从围绕FC的区域向周边转运.%Processing of pre-rRNA is one of the major events taking place in the nucleolus. U3 snoRNA, an rRNA spliceosomal factor, is suggested to be essential in the first cleavage step of the 5′ ETS sequence in the processing of pre-rRNA. Identification of U3 in the nucleolus provides a piece of indirect evidence for pre-rRNA processing site and transportation of processing products. In the present study, subnucleolar distribution of U3 snoRNA in the nucleolus of Pisum sativum L. was studied by in situ hybridization with a U3 snoRNA probe. The results showed that the U3 labeling signals were distributed throughout dense fibrillar components (DFCs) and granular components (GCs), while no signal was found in fibrillar centers (FCs). When treated with actinomycine D (AMD), the labeling signals were decreased. Along with the increase of the AMD treatment time, the labeling signals became fewer and they were found in the distal regions of DFC and GC. Our results indicated that pre-rRNA splicing took place in the regions of DFC and GC, and the transportation of pre-rRNA processing products was from the regions around FCs towards the distal

  8. Three-dimensional imaging of nucleolin trafficking in normal cells, transfectants, and heterokaryons

    Science.gov (United States)

    Ballou, Byron T.; Fisher, Gregory W.; Deng, Jau-Shyong; Hakala, Thomas R.; Srivastava, Meera; Farkas, Daniel L.

    1996-04-01

    The study of intracellular trafficking using labeled molecules has been aided by the development of the cyanine fluorochromes, which are easily coupled, very soluble, resist photobleaching, and fluoresce at far-red wavelengths where background fluorescence is minimal. We have used Cy3-, Cy5-, and Cy5.5-labeled antibodies, antigen-binding fragments, and specifically binding single-stranded oligonucleotides to follow expression and trafficking of nucleolin, the most abundant protein of the nucleolus. Nucleolin shuttles between the nucleolus and the cytoplasm, and is also expressed on the cell surface, allowing us to test our techniques at all three cellular sites. Differentially cyanine-labeled non-specific antibodies were used to control for non-specific binding. Similarly, the differentially labeled non-binding strand of the cloned oligonucleotide served as a control. The multimode microscope allowed us to follow both rapid and slow redistributions of labeled ligands in the same study. We also performed 3-D reconstructions of nucleolin distribution in cells using rapid acquisition and deconvolution. Microinjection of labeled ligands was used to follow intracellular distribution, while incubation of whole cells with antibody and antigen-binding fragments was used to study uptake. To unambiguously define trafficking, and eliminate the possibility of interference by cross-reactive proteins, we transfected mouse renal cell carcinoma cells that express cell surface nucleolin with human nucleolin. We used microinjection and cell surface staining with Cy3- or Cy5- labeled monoclonal antibody D3 (specific for human nucleolin) to assess the cellular distribution of the human protein. Several clones expressed human nucleolin on their surfaces and showed high levels of transport of the human protein into the mouse nucleus and nucleolus. This distribution roughly parallels that of mouse nucleolin as determined by labeled polyclonal antibody. We have used these engineered

  9. Novel endoscopic imaging techniques toward in vivo observation of living cancer cells in the gastrointestinal tract.

    Science.gov (United States)

    Inoue, Haruhiro; Kudo, Shin-ei; Shiokawa, Akira

    2005-07-01

    It is now possible to perform microscopic imaging of living cells from both normal mucosa and malignant tissue in the gastrointestinal tract. Endocytoscopy is a catheter-type contact endoscope that has more than 1000-fold magnifying power and can pass through the working channel of the straight-view endoscope. In esophageal cells, the nucleus, cell body, and even the nucleolus were clearly distinguished with high-resolution images comparable with those of conventional cytology. This novel technology has the potential to provide histologic diagnoses during endoscopic examinations, similar to those obtained currently by conventional histology techniques.

  10. Nuclear localization of phosphorylated c-Myc protein in human tumor cells.

    Directory of Open Access Journals (Sweden)

    C. Soldani

    2010-05-01

    Full Text Available Using immunocytochemical techniques at light and electron microscopy, we analysed the distribution of phosphorylated c-Myc in actively proliferating human HeLa cells. The distribution pattern of c-Myc was also compared with those of other ribonucleoprotein (RNP-containing components (PANA, hnRNP-core proteins, fibrillarin or RNP-associated nuclear proteins (SC-35 splicing factor. Our results provide the first evidence that phosphorylated c-Myc accumulates in the nucleus of tumor cells, where it colocalizes with fibrillarin, both in the nucleolus and in extranucleolar structures.

  11. High-resolution microscopy of active ribosomal genes and key members of the rRNA processing machinery inside nucleolus-like bodies of fully-grown mouse oocytes.

    Science.gov (United States)

    Shishova, Kseniya V; Khodarovich, Yuriy M; Lavrentyeva, Elena A; Zatsepina, Olga V

    2015-10-01

    Nucleolus-like bodies (NLBs) of fully-grown (germinal vesicle, GV) mammalian oocytes are traditionally considered as morphologically distinct entities, which, unlike normal nucleoli, contain transcribed ribosomal genes (rDNA) solely at their surface. In the current study, we for the first time showed that active ribosomal genes are present not only on the surface but also inside NLBs of the NSN-type oocytes. The "internal" rRNA synthesis was evidenced by cytoplasmic microinjections of BrUTP as precursor and by fluorescence in situ hybridization with a probe to the short-lived 5'ETS segment of the 47S pre-rRNA. We further showed that in the NLB mass of NSN-oocytes, distribution of active rDNA, RNA polymerase I (UBF) and rRNA processing (fibrillarin) protein factors, U3 snoRNA, pre-rRNAs and 18S/28S rRNAs is remarkably similar to that in somatic nucleoli capable to make pre-ribosomes. Overall, these observations support the occurrence of rDNA transcription, rRNA processing and pre-ribosome assembly in the NSN-type NLBs and so that their functional similarity to normal nucleoli. Unlike the NSN-type NLBs, the NLBs of more mature SN-oocytes do not contain transcribed rRNA genes, U3 snoRNA, pre-rRNAs, 18S and 28S rRNAs. These results favor the idea that in a process of transformation of NSN-oocytes to SN-oocytes, NLBs cease to produce pre-ribosomes and, moreover, lose their rRNAs. We also concluded that a denaturing fixative 70% ethanol used in the study to fix oocytes could be more appropriate for light microscopy analysis of nucleolar RNAs and proteins in mammalian fully-grown oocytes than a commonly used cross-linking aldehyde fixative, formalin.

  12. [Analysis of the Localization of Fibrillarin and Sites of Pre-rRNA Synthesis in the Nucleolus-Like Bodies of Mouse GV Oocytes after Mild Treatment with Proteinase K].

    Science.gov (United States)

    Shishova, K V; Khodarovich, Yu M; Lavrentyeva, E A; Zatsepina, O V

    2015-01-01

    Postnatal development of mammalian oocytes is accompanied by functional and structural remodeling of the nucleolar apparatus: the final stage of this process is the formation of large objects (up to 10 μm in diameter) termed nucleolus-like bodies (NLBs) in preovulatory GV oocytes. N LB material was shown to be essential for early embryonic development, but its composition is still uncharacterized. In the present study, the protein-binding dye fluorescein-5-isothiocyanate (FITC) was used to show that proteins characterized by a high local concentration are essential NLB components in mouse GV oocytes. One of these proteins was able to be identified for the first time using a mild treatment of oocytes with proteinase K; the protein identified was fibrillarin, a factor of early pre-rRNA processing. Fibrillarin is present in the inner NLB mass of all oocytes capable of synthesizing rRNA; however, it is not colocalized with BrUTP microinjected into oocytes in order to identify transcribed ribosomal genes, in contrast to the "surface" fibrillarin. These observations imply the accumulation of nucleolar proteins not involved in ribosome biogenesis inside the NLB. All NLBs present in an individual nucleus of an NSN-type GV oocyte contain fibrillarin and are associated with active ribosomal genes. The results obtained in the present work demonstrate that proteinase K treatment of GV mouse oocytes allows for: (1) identification of "cryptic" proteins inside the densely packed NLB material and (2) the enhancement of oocyte image quality during BrUTP-based identification of rRNA synthesis sites but (3) not for the detection of active ribosomal genes in the inner mass of the NLB. The fluorescent dye FITC can be recommended for assessment of intracellular protein localization in the oocytes of all mammalian species.

  13. Oncotripsy: Targeting cancer cells selectively via resonant harmonic excitation

    CERN Document Server

    Heyden, Stefanie

    2015-01-01

    We investigate a method of selectively targeting cancer cells by means of ultrasound harmonic excitation at their resonance frequency, which we refer to as oncotripsy. The geometric model of the cells takes into account the cytoplasm, nucleus and nucleolus, as well as the plasma membrane and nuclear envelope. Material properties are varied within a pathophysiologically-relevant range. A first modal analysis reveals the existence of a spectral gap between the natural frequencies and, most importantly, resonant growth rates of healthy and cancerous cells. The results of the modal analysis are verified by simulating the fully-nonlinear transient response of healthy and cancerous cells at resonance. The fully nonlinear analysis confirms that cancerous cells can be selectively taken to lysis by the application of carefully tuned ultrasound harmonic excitation while simultaneously leaving healthy cells intact.

  14. Oncotripsy: Targeting cancer cells selectively via resonant harmonic excitation

    Science.gov (United States)

    Heyden, S.; Ortiz, M.

    2016-07-01

    We investigate a method of selectively targeting cancer cells by means of ultrasound harmonic excitation at their resonance frequency, which we refer to as oncotripsy. The geometric model of the cells takes into account the cytoplasm, nucleus and nucleolus, as well as the plasma membrane and nuclear envelope. Material properties are varied within a pathophysiologically-relevant range. A first modal analysis reveals the existence of a spectral gap between the natural frequencies and, most importantly, resonant growth rates of healthy and cancerous cells. The results of the modal analysis are verified by simulating the fully-nonlinear transient response of healthy and cancerous cells at resonance. The fully nonlinear analysis confirms that cancerous cells can be selectively taken to lysis by the application of carefully tuned ultrasound harmonic excitation while simultaneously leaving healthy cells intact.

  15. [Calcium distribution in the egg cell, zygote and proembryo of lettuce (Lactuca sativa L.)].

    Science.gov (United States)

    Qiu, Yi Lan; Liu, Ru Shi; Wei, Dong Mei; Tian, Hui Qiao

    2006-02-01

    Potassium antimonite precipitation was used to located calcium in the egg cells (before and after anthesis), zygotes and proembryos of lettuce (Lactuca sativa L.). A few calcium precipitates (ppts) were located in the small vacuoles of cytoplasm of egg cell at 3 d before anthesis, when egg cells just formed. Then the small vacuoles fused to form some bigger vacuoles in egg cell at 2d before anthesis. Calcium ppts increased evidently in the cytoplasm and nucleus of egg cells at this time. At 1d before anthesis, a biggest vacuole located at the micropyle end of the cell and its nucleus was pushed toward the chalazal end of the cell, which made an evident cellular polarity. The number of calcium ppts in the egg cell markedly decreased, suggesting that change of calcium distribution may be related to the development of egg cell. After anthesis and before fertilization, calcium ppts were still few in the egg cells, and most of them were accumulated in the nucleus, especially in the vacuoles of nucleolus. At 4h after anthesis, egg cell was fertilized and the wall at the chalazal end of egg cell was formed completely. Calcium ppts evidently increased again in egg cell, and some big ppts appeared in the karyoplasm of nucleus and abundant small ppts in the large vacuole. At 9h after anthesis, zygote completed its first division. Calcium ppts in the nucleus and cytoplasm of two-celled proembryo began to decrease, and only some ones accumulated in the vacuoles of nucleolus. At 18h after anthesis, zygote divided several times and became a multi-celled proembryo. Calcium ppts in the cells of proembryo ulteriorly diminished but there were many ppts on the surface of proembryo. The result indicates that calcium in egg cell, zygote and the cells of proembryo orderly changes its temporal and spatial position, which suggests that calcium may play a role during the development of egg cell and zygote.

  16. Clinical application value of hard nucleolus cataract surgery with sutureless large incision in primary hospitals%无缝线中切口硬核白内障手术在基层医院临床应用

    Institute of Scientific and Technical Information of China (English)

    何新

    2015-01-01

    Objective To summarize and explore the effect of hard nuclcolus cataract surgery with sutureless large incision.Methods A retrospective analysis was made on the clinical data of 168 patients with hard nucleolus cataract received extracapsular cataract extraction with sutureless large incision from January 2009 to December 2013 in People's Hospital of Xuan'en County.Results Through comparing uncorrected visual acuity when one day, one week and three months after surgery with before surgery in 168 patients with cataract surgery, there were significant differences (x2=255.21, P =0.000;x2=431.46, P =0.000;x2=401.98, P =0.000).Conclusions Extracapsular cataract extraction with sutureless large incision is inexpensive, safe and easy to master, and the learning curve is short and the effect is good.It is suitable for development in the primary hospitals.%目的 总结并探讨无缝线中切口硬核白内障手术的效果.方法 回顾性分析2009年1月至2013年12月在宣恩县人民医院眼科就诊的168只眼硬核患者行无缝线中切口白内障囊外摘除术临床资料.结果 168只眼手术后1天、手术后1周、手术后3个月裸眼视力与术前比较,差异有统计学意义(x2=255.21,P=0.000;x2=431.46,P=0.000;x2=401.98,P=0.000).结论 无缝线中切口白内障囊外摘除术投资少、安全、容易掌握、学习曲线短、效果好,适合在基层医院开展.

  17. On the Nucleolus of Neighbour Games

    NARCIS (Netherlands)

    Hamers, H.J.M.; Klijn, F.; Solymosi, T.; Tijs, S.H.; Vermeulen, D.

    1999-01-01

    The class of neighbour games is the intersection of the class of assignment games (cf. Shapley and Shubik (1972)) and the class of component additive games (cf. Curiel et al. (1994)). For assignment games and component additive games there exist polynomially bounded algorithms of order p4 for calcul

  18. 普通小麦与非洲黑麦双二倍体中随体、醇溶蛋白%Intergenomic Interaction of Nucleolus, Gliadin and Disease Resistance in a Triticum Aestivum-Secale Africanum Amphiploid

    Institute of Scientific and Technical Information of China (English)

    杨足君; 李光蓉; 蒋华仁; 任正隆

    2001-01-01

    An amphiploid between Triticum aestivum native to Sichuan, China, and Secale africanum was evaluated by cytological observatio n, seed storage protein electrophoresis analysis and diseases resistance surveys . Feulgen staining of somatic metaphases indicates that the nucleolus from S.africanum is partially expressed in the amphiploid. The S.africanum chromosomes can be identified in amphiploid backgrou nd by Giemsa-C banding. APAGE shows that most gliadin of both parents is observ ed in the endosperm of the amphiploid with codominant expression, except the agg regation secalin of S.africanum. By inoculating the stripe rust and powdery mildew isolates, it is found that diseases resistance from S .africanum are not totally expressed in the amphiploid. In addition, the wheat-alien intergenomic interaction and the utilization of the amphiploid to triticale and wheat breeding are discussed in the present paper.%利用细胞学方法、种子储藏蛋白电泳技术和抗病接种鉴定对四川小麦地方品种与非洲黑麦(S.africanum)人工合成双二倍体进行了研究,结果表明: ①根尖细胞的染色体计数发现,来自非洲黑麦的随体在双二倍体中仅得到部分表达;Giemsa-C带分析能准确鉴定双二倍体中的非洲黑麦染色体,发现非洲黑麦与栽培黑麦的染色体C带有较大的区别;②种子醇溶蛋白电泳发现除非洲黑麦的聚集黑麦碱蛋白在双二倍体中不表达外,其余来自普通小麦和非洲黑麦的相应蛋白带能够在双二倍体中正常表达;③双二倍体及其亲本的苗期抗白粉病性和成株期抗条锈性分析表明,非洲黑麦对这两种病害的优良抗性在双二倍体中并不表达,抗性受到普通小麦背景的抑制.另外本文对小麦-外源染色体组的相互作用和该双二倍体在小麦与八倍体小黑麦育种中的应用进行了讨论.

  19. Localization and translocation of RhoA protein in the human gastric cancer cell line SGC-7901

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM: To elucidate the localization of RhoA in gastric SGC-7901 cancer cells and its translocation by lysophosphatidic acid (LPA) and/or 8-chlorophenylthio cAMP (CPT-cAMP). METHODS: Immunofluorescence microscopy was used to determine the localization of RhoA. Western blotting was used to detect both endogenous and exogenous RhoA in different cellular compartments (membrane, cytosol, nucleus) and the translocation of RhoA following treatment with LPA, CPT-cAMP, or CPT-cAMP+LPA. RESULTS: Immunofluorescence staining revealed endogenous RhoA to be localized in the membrane, the cytosol, and the nucleus, and its precise localization within the nucleus to be the nucleolus. Western blotting identified both endogenous and exogenous RhoA within different cellular compartments (membrane, cytosol, nucleus, nucleolus). After stimulation with LPA, the amount of RhoA within membrane and nuclear extracts increased, while it decreased in the cytosol fractions. After treatment with CPT-cAMP the amount of RhoA within the membrane and the nuclear extracts decreased, while it increased within the cytosol fraction. Treatment with a combination of both substances led to a decrease in RhoA in the membrane and the nucleus but to an increase in the cytosol. CONCLUSION: In SGC-7901 cells RhoA was found to be localized within the membrane, the cytosol, and the nucleus. Within the nucleus its precise localization could be demonstrated to be the nucleolus. Stimulation with LPA caused a translocation of RhoA from the cytosol towards the membrane and the nucleus; treatment with CPT-cAMP caused the opposite effect. Furthermore, pre-treatment with CPT-cAMP was found to block the effect of LPA.

  20. Construction of a fusion protein expression vector MK-EGFP and its subcellular localization in different carcinoma cell lines

    Institute of Scientific and Technical Information of China (English)

    Li-Cheng Dai; Di-Yong Xu; Xing Yao; Li-Shan Min; Ning Zhao; Bo-Ying Xu; Zheng-Ping Xu; Yong-Liang Lu

    2006-01-01

    AIM: To construct an expression plasmid encoding human wild-type midkine (MK) and enhanced green fluorescence protein (EGFP) fusion protein (MK-EGFP), and to analyze the subcellular localization of MK in different carcinoma cell lines.METHODS: Two kinds of MK coding sequences with or without signal peptide were cloned into plasmid pEGFP-N2, and the recombinant plasmids constructed were introduced into HepG2, MCF7 and DU145 cells,respectively, by transfection. With the help of laser scanning confocal microscopy, the expression and subcellular localization of MK-GFP fusion protein could be detected.RESULTS: Compared with the GFP control, in which fluorescence was detected diffusely over the entire cell body except in the nucleolus, both kinds of fusion protein MK-GFP were localized exclusively to the nucleus and accumulated in the nucleolus in the three kinds of cancer cell lines.CONCLUSION: This study reveals the specific nucleolar translocation independent of signal peptide, which may be involved in the mechanism that MK works. It provides valuable evidence for further study on the functions of MK in nucleus and its possible mechanisms, in which ribosomal RNA transcription and ribosome assembly are involved.

  1. Nuclear and nuclear reprogramming during the first cell cycle in bovine nuclear transfer embryos

    DEFF Research Database (Denmark)

    Østrup, Olga; Petrovicova, Ida; Strejcek, Frantisek

    2009-01-01

    Abstract The immediate events of genomic reprogramming at somatic cell nuclear transfer (SCNT) are to high degree unknown. This study was designed to evaluate the nuclear and nucleolar changes during the first cell cycle. Bovine SCNT embryos were produced from starved bovine fibroblasts and fixed......, somatic cell nuclei introduced into enucleated oocytes displayed chromatin condensation, partial nuclear envelope breakdown, nucleolar desegregation and transcriptional quiescence already at 0.5 hpa. Somatic cell cytoplasm remained temporally attached to introduced nucleus and nucleolus was partially...... restored indicating somatic influence in the early SCNT phases. At 1-3 hpa, chromatin gradually decondensed toward the nucleus periphery and nuclear envelope reformed. From 4 hpa, the somatic cell nucleus gained a PN-like appearance and displayed NPBs suggesting ooplasmic control of development....

  2. Indole-based cyanine as a nuclear RNA-selective two-photon fluorescent probe for live cell imaging.

    Science.gov (United States)

    Guo, Lei; Chan, Miu Shan; Xu, Di; Tam, Dick Yan; Bolze, Frédéric; Lo, Pik Kwan; Wong, Man Shing

    2015-05-15

    We have demonstrated that the subcellular targeting properties of the indole-based cyanines can be tuned by the functional substituent attached onto the indole moiety in which the first example of a highly RNA-selective and two-photon active fluorescent light-up probe for high contrast and brightness TPEF images of rRNA in the nucleolus of live cells has been developed. It is important to find that this cyanine binds much stronger toward RNA than DNA in a buffer solution as well as selectively stains and targets to rRNA in the nucleolus. Remarkably, the TPEF brightness (Φσmax) is dramatically increased with 11-fold enhancement in the presence of rRNA, leading to the record high Φσmax of 228 GM for RNA. This probe not only shows good biocompatibility and superior photostability but also offers general applicability to various live cell lines including HeLa, HepG2, MCF-7, and KB cells and excellent counterstaining compatibility with commercially available DNA or protein trackers.

  3. Ultrastructural localization of active genes in Allium cepa cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    By using the anti-RNA/DNA hybrid antibody as the probe, we labeled and analyzed the precise transcriptional sites of active genes in Allium cepa cells in situ. The results showed that the location of labeled signals appeared in mitochondrion was the same as that in chloroplast, generally concentrated at the central matrix space where there were no cristae and thylakoids. In the extranucleolar regions of nucleus, the labeled signals of transcriptional sites were situated at the perichromatin fibrils, which decondensed and stretched out from the chromosome territories. Our results also displayed the concentrations of labeled signals in a cer-tain region of nucleus, and this means that the gene tran-scription rich region actually existed in Allium cepa cells. In nucleolus, the synthetic sites of rRNA were localized not only to the periphery of fibrillar centers but also to the DFC near FC.

  4. Subcellular SIMS imaging of isotopically labeled amino acids in cryogenically prepared cells

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, Subhash

    2004-06-15

    Ion microscopy is a potentially powerful technique for localization of isotopically labeled molecules. In this study, L-arginine and phenylalanine amino acids labeled with stable isotopes {sup 13}C and {sup 15}N were localized in cultured cells with the ion microscope at 500 nm spatial resolution. Cells were exposed to the labeled amino acids and cryogenically prepared. SIMS analyses were made in fractured freeze-dried cells. A dynamic distribution was observed from labeled arginine-treated LLC-PK{sub 1} kidney cells at mass 28 ({sup 13}C{sup 15}N) in negative secondaries, revealing cell-to-cell heterogeneity and preferential accumulation of the amino acid (or its metabolite) in the nucleus and nucleolus of some cells. The smaller nucleolus inside the nucleus was clearly resolved in SIMS images and confirmed by correlative light microscopy. The distribution of labeled phenylalanine contrasted with arginine as it was rather homogeneously distributed in T98G human glioblastoma cells. Images of {sup 39}K, {sup 23}Na and {sup 40}Ca were also recorded to confirm the reliability of sample preparation and authenticity of the observed amino acid distributions. These observations indicate that SIMS techniques can provide a valuable technology for subcellular localization of nitrogen-containing molecules in proteomics since nitrogen does not have a radionuclide tracer isotope. Amino acids labeled with stable isotopes can be used as tracers for studying their transport and metabolism in distinct subcellular compartments with SIMS. Further studies of phenylalanine uptake in human glioblastoma cells may have special significance in boron neutron capture therapy (BNCT) as a boron analogue of phenylalanine, boronophenylalanine is a clinically approved compound for the treatment of brain tumors.

  5. Subcellular SIMS imaging of isotopically labeled amino acids in cryogenically prepared cells

    Science.gov (United States)

    Chandra, Subhash

    2004-06-01

    Ion microscopy is a potentially powerful technique for localization of isotopically labeled molecules. In this study, L-arginine and phenylalanine amino acids labeled with stable isotopes 13C and 15N were localized in cultured cells with the ion microscope at 500 nm spatial resolution. Cells were exposed to the labeled amino acids and cryogenically prepared. SIMS analyses were made in fractured freeze-dried cells. A dynamic distribution was observed from labeled arginine-treated LLC-PK 1 kidney cells at mass 28 ( 13C15N) in negative secondaries, revealing cell-to-cell heterogeneity and preferential accumulation of the amino acid (or its metabolite) in the nucleus and nucleolus of some cells. The smaller nucleolus inside the nucleus was clearly resolved in SIMS images and confirmed by correlative light microscopy. The distribution of labeled phenylalanine contrasted with arginine as it was rather homogeneously distributed in T98G human glioblastoma cells. Images of 39K, 23Na and 40Ca were also recorded to confirm the reliability of sample preparation and authenticity of the observed amino acid distributions. These observations indicate that SIMS techniques can provide a valuable technology for subcellular localization of nitrogen-containing molecules in proteomics since nitrogen does not have a radionuclide tracer isotope. Amino acids labeled with stable isotopes can be used as tracers for studying their transport and metabolism in distinct subcellular compartments with SIMS. Further studies of phenylalanine uptake in human glioblastoma cells may have special significance in boron neutron capture therapy (BNCT) as a boron analogue of phenylalanine, boronophenylalanine is a clinically approved compound for the treatment of brain tumors.

  6. Nucleolar re-activation is delayed in mouse embryos cloned from two different cell lines

    DEFF Research Database (Denmark)

    Svarcova, Olga; Dinnyes, A.; Polgar, Z.

    2009-01-01

    displayed early NPBs transformation. In conclusion, despite normal onset of EGA in cloned embryos, activation of functional nucleoli was one cell cycle delayed in NT embryos. NT-MEF embryos displayed normal targeting but delayed activation of nucleolar proteins. Contrary, in NT-HM1 embryos, both......Aim of this study was to evaluate and compare embryonic genome activation (EGA) in mouse embryos of different origin using nucleolus as a marker. Early and late 2-cell and late 4-cell stage embryos, prepared by in vitro fertilization (IVF), parthenogenetic activation (PG), and nuclear transfer...... ofmouse embryonic fibroblast (MEF) and mouse HM1 emryonic stem cells (HM1), were processed for autoradiography following 3H-uridine incubation (transcriptional activity), transmission electron microscopy (ultrastructure) and immunofluorescence (nucleolar proteins; upstream binding factor, UBF...

  7. Changes in the number and size of nucleoli of Chara vulgaris L. antheridial filament cells during the period preceding light-induced re-initiation of cell divisions following a mitodepressive effect of darkness

    Directory of Open Access Journals (Sweden)

    Maria Kwiatkowska

    2014-02-01

    Full Text Available The changes in number and size of nucleoli of Chara vulgaris antheridial filament cells were monitored with the use of Howell and Black's silver staining method. After a 3-day mitodepressive treatment with darkness the cells were exposed to light which reactivated mitotic activity after 18-20 hours. Eight-celled antheridial filaments were observed. In the period preceding light-induced re-initiation of mitoses a gradual reconstruction of the number and size of nucleoli characteristic of control, as well as their total area per nucleus appeared. The obtained results indicate that one of the important conditions for a cell to be able to divide is accumulation of nucleolus components characteristic of a given developmental stage and this controls nucleologenesis of the subsequent cell cycle.

  8. Localization of a bacterial group II intron-encoded protein in eukaryotic nuclear splicing-related cell compartments.

    Directory of Open Access Journals (Sweden)

    Rafael Nisa-Martínez

    Full Text Available Some bacterial group II introns are widely used for genetic engineering in bacteria, because they can be reprogrammed to insert into the desired DNA target sites. There is considerable interest in developing this group II intron gene targeting technology for use in eukaryotes, but nuclear genomes present several obstacles to the use of this approach. The nuclear genomes of eukaryotes do not contain group II introns, but these introns are thought to have been the progenitors of nuclear spliceosomal introns. We investigated the expression and subcellular localization of the bacterial RmInt1 group II intron-encoded protein (IEP in Arabidopsis thaliana protoplasts. Following the expression of translational fusions of the wild-type protein and several mutant variants with EGFP, the full-length IEP was found exclusively in the nucleolus, whereas the maturase domain alone targeted EGFP to nuclear speckles. The distribution of the bacterial RmInt1 IEP in plant cell protoplasts suggests that the compartmentalization of eukaryotic cells into nucleus and cytoplasm does not prevent group II introns from invading the host genome. Furthermore, the trafficking of the IEP between the nucleolus and the speckles upon maturase inactivation is consistent with the hypothesis that the spliceosomal machinery evolved from group II introns.

  9. Evidence of programmed cell death during microsporogenesis in an interspecific Brachiaria (Poaceae: Panicoideae: Paniceae) hybrid.

    Science.gov (United States)

    Fuzinatto, V A; Pagliarini, M S; Valle, C B

    2007-05-11

    Morphological changes have been investigated during plant programmed cell death (PCD) in the last few years due to the new interest in a possible apoptotic-like phenomenon existing in plants. Although PCD has been reported in several tissues and specialized cells in plants, there have been few reports of its occurrence during microsporogenesis. The present study reports a typical process of PCD during meiosis in an interspecific Brachiaria hybrid leading to male sterility. In this hybrid, some inflorescences initiated meiosis but it was arrested in zygotene/pachytene. From this stage, meiocytes underwent a severe alteration in shape showing substantial membrane blebbing; the cytoplasm became denser at the periphery; the cell nucleus entered a progressive stage of chromatin disintegration, and then the nucleolus disintegrated, and the cytoplasm condensed and shrunk. The oldest flowers of the raceme showed only the callose wall in the anthers showing obvious signs of complete sterility.

  10. Nop2 is expressed during proliferation of neural stem cells and in adult mouse and human brain.

    Science.gov (United States)

    Kosi, Nina; Alić, Ivan; Kolačević, Matea; Vrsaljko, Nina; Jovanov Milošević, Nataša; Sobol, Margarita; Philimonenko, Anatoly; Hozák, Pavel; Gajović, Srećko; Pochet, Roland; Mitrečić, Dinko

    2015-02-09

    The nucleolar protein 2 gene encodes a protein specific for the nucleolus. It is assumed that it plays a role in the synthesis of ribosomes and regulation of the cell cycle. Due to its link to cell proliferation, higher expression of Nop2 indicates a worse tumor prognosis. In this work we used Nop2(gt1gaj) gene trap mouse strain. While lethality of homozygous animals suggested a vital role of this gene, heterozygous animals allowed the detection of expression of Nop2 in various tissues, including mouse brain. Histochemistry, immunohistochemistry and immunoelectron microscopy techniques, applied to a mature mouse brain, human brain and on mouse neural stem cells revealed expression of Nop2 in differentiating cells, including astrocytes, as well as in mature neurons. Nop2 was detected in various regions of mouse and human brain, mostly in large pyramidal neurons. In the human, Nop2 was strongly expressed in supragranular and infragranular layers of the somatosensory cortex and in layer III of the cingulate cortex. Also, Nop2 was detected in CA1 and the subiculum of the hippocampus. Subcellular analyses revealed predominant location of Nop2 within the dense fibrillar component of the nucleolus. To test if Nop2 expression correlates to cell proliferation occurring during tissue regeneration, we induced strokes in mice by middle cerebral artery occlusion. Two weeks after stroke, the number of Nop2/nestin double positive cells in the region affected by ischemia and the periventricular zone substantially increased. Our findings suggest a newly discovered role of Nop2 in both mature neurons and in cells possibly involved in the regeneration of nervous tissue.

  11. Passive diffusion of naltrexone into human and animal cells and upregulation of cell proliferation.

    Science.gov (United States)

    Cheng, Fan; McLaughlin, Patricia J; Banks, William A; Zagon, Ian S

    2009-09-01

    Naltrexone (NTX) is a potent opioid antagonist that promotes cell proliferation by upregulating DNA synthesis through displacement of the tonically active inhibitory peptide, opioid growth factor (OGF) from its receptor (OGFr). To investigate how NTX enters cells, NTX was fluorescently labeled [1-(N)-fluoresceinyl NTX thiosemicarbazone; FNTX] to study its uptake by living cultured cells. When human head and neck squamous cell carcinoma cell line (SCC-1) was incubated with FNTX for as little as 1 min, cells displayed nuclear and cytoplasmic staining of FNTX as determined by fluorescent deconvolution microscopy, with enrichment of fluorescent signal in the nucleus and nucleolus. The same temporal-spatial distribution of FNTX was detected in a human pancreatic cancer cell line (MIA PaCa-2), African green monkey kidney cell line (COS-7), and human mesenchymal stem cells (hMSCs). FNTX remained in cells for as long as 48 h. FNTX was internalized in SCC-1 cells when incubation occurred at 4 degrees C, with the signal being comparable to that recorded at 37 degrees C. A 100-fold excess of NTX or a variety of other opioid ligands did not alter the temporal-spatial distribution of FNTX. Neither fluorescein-labeled dextran nor fluorescein alone entered the cells. To study the effect of FNTX on DNA synthesis, cells incubated with FNTX at concentrations ranging from 10(-5) to 10(-8) M had a 5-bromo-2'-deoxyuridine index that was 39-82% greater than for vehicle-treated cells and was comparable to that of unlabeled NTX (37-70%). Taken together, these results suggested that NTX enters cells by passive diffusion in a nonsaturable manner.

  12. Monitoring the RNA distribution in human embryonic stem cells using Raman micro-spectroscopy and fluorescence imaging

    Science.gov (United States)

    Falamas, A.; Kalra, S.; Chis, V.; Notingher, I.

    2013-11-01

    The aim of this study was to monitor the intracellular distribution of nucleic acids in human embryonic stem cells. Raman micro-spectroscopy and fluorescence imaging investigations were employed to obtain high-spatial resolution maps of nucleic acids. The DNA Raman signal was identified based on the 782 cm-1 band, while the RNA characteristic signal was detected based on the 813 cm-1 fingerprint band assigned to O-P-O symmetric stretching vibrations. Additionally, principal components analysis was performed and nucleic acids characteristic Raman signals were identified in the data set, which were plotted at each position in the cells. In this manner, high intensity RNA signal was identified in the cells nucleolus and cytoplasm, while the nucleus presented a much lower signal.

  13. Evaluation of Simulated Microgravity Environments Induced by Diamagnetic Levitation of Plant Cell Suspension Cultures

    Science.gov (United States)

    Kamal, Khaled Y.; Herranz, Raúl; van Loon, Jack J. W. A.; Christianen, Peter C. M.; Medina, F. Javier

    2016-06-01

    Ground-Based Facilities (GBF) are essetial tools to understand the physical and biological effects of the absence of gravity and they are necessary to prepare and complement space experiments. It has been shown previously that a real microgravity environment induces the dissociation of cell proliferation from cell growth in seedling root meristems, which are limited populations of proliferating cells. Plant cell cultures are large and homogeneous populations of proliferating cells, so that they are a convenient model to study the effects of altered gravity on cellular mechanisms regulating cell proliferation and associated cell growth. Cell suspension cultures of the Arabidopsis thaliana cell line MM2d were exposed to four altered gravity and magnetic field environments in a magnetic levitation facility for 3 hours, including two simulated microgravity and Mars-like gravity levels obtained with different magnetic field intensities. Samples were processed either by quick freezing, to be used in flow cytometry for cell cycle studies, or by chemical fixation for microscopy techniques to measure parameters of the nucleolus. Although the trend of the results was the same as those obtained in real microgravity on meristems (increased cell proliferation and decreased cell growth), we provide a technical discussion in the context of validation of proper conditions to achieve true cell levitation inside a levitating droplet. We conclude that the use of magnetic levitation as a simulated microgravity GBF for cell suspension cultures is not recommended.

  14. Cells

    Directory of Open Access Journals (Sweden)

    Zhao-Hui Jin

    2012-11-01

    Full Text Available As cancer stem cells (CSCs are postulated to play critical roles in cancer development, including metastasis and recurrence, CSC imaging would provide valuable information for cancer treatment and lead to CSC-targeted therapy. To assess the possibility of in vivo CSC targeting, we conducted basic studies on radioimmunotargeting of cancer cells positive for CD133, a CSC marker recognized in various cancers. Antibodies against CD133 were labeled with 125I, and their in vitro cell binding properties were tested. Using the same isotype IgG as a control, in vivo biodistribution of the labeled antibody retaining immunoreactivity was examined in mice bearing an HCT116 xenograft in which a population of the cancer cells expressed CD133. Intratumoral distribution of the labeled antibody was examined and compared to the CD133 expression pattern. The 125I-labeled anti-CD133 antibody showed a modest but significantly higher accumulation in the HCT116 xenograft compared to the control IgG. The intratumoral distribution of the labeled antibody mostly overlapped with the CD133 expression, whereas the control IgG was found in the area close to the necrotic tumor center. Our results indicate that noninvasive in vivo targeting of CSCs could be possible with radiolabeled antibodies against cell membrane markers.

  15. Werner complex deficiency in cells disrupts the Nuclear Pore Complex and the distribution of lamin B1.

    Science.gov (United States)

    Li, Zhi; Zhu, Yizhou; Zhai, Yujia; R Castroagudin, Michelle; Bao, Yifei; White, Tommy E; Glavy, Joseph S

    2013-12-01

    From the surrounding shell to the inner machinery, nuclear proteins provide the functional plasticity of the nucleus. This study highlights the nuclear association of Pore membrane (POM) protein NDC1 and Werner protein (WRN), a RecQ helicase responsible for the DNA instability progeria disorder, Werner Syndrome. In our previous publication, we connected the DNA damage sensor Werner's Helicase Interacting Protein (WHIP), a binding partner of WRN, to the NPC. Here, we confirm the association of the WRN/WHIP complex and NDC1. In established WRN/WHIP knockout cell lines, we further demonstrate the interdependence of WRN/WHIP and Nucleoporins (Nups). These changes do not completely abrogate the barrier of the Nuclear Envelope (NE) but do affect the distribution of FG Nups and the RAN gradient, which are necessary for nuclear transport. Evidence from WRN/WHIP knockout cell lines demonstrates changes in the processing and nucleolar localization of lamin B1. The appearance of "RAN holes" void of RAN corresponds to regions within the nucleolus filled with condensed pools of lamin B1. From WRN/WHIP knockout cell line extracts, we found three forms of lamin B1 that correspond to mature holoprotein and two potential post-translationally modified forms of the protein. Upon treatment with topoisomerase inhibitors lamin B1 cleavage occurs only in WRN/WHIP knockout cells. Our data suggest the link of the NDC1 and WRN as one facet of the network between the nuclear periphery and genome stability. Loss of WRN complex leads to multiple alterations at the NPC and the nucleolus.

  16. Ultrastructural study of the chromatoid body in planarian regenerative cells

    Energy Technology Data Exchange (ETDEWEB)

    Hori, I. (Kanazawa Medical Univ., Ishikawa (Japan))

    1982-04-01

    The present paper deals with the ultrastructural changes of chromatoid bodies in planarian regenerative cells under normal and experimental conditions. A close relationship was usually observed between chromatoid bodies and pore regions of the nuclear envelope in these cells. The chromatoid bodies continued to decrease in size during cytodifferentiation of regenerative cells, though they did not disappear entirely throughout the regeneration processes. Cytochemistry and (/sup 3/H)uridine autoradiography have shown that the chromatoid body contains RNA. The typical morphological effect of actinomycin D became apparent in three organelles, i.e., nucleolus, polysome and chromatoid body. Ultrastructural changes in nucleoli were observed to occur after actinomycin treatment (20 ..mu..g/ml). The exposure to a higher dose of actinomycin (50 ..mu..g/ml) caused a decay of chromatoid bodies while nuclear envelopes retained numerous pores. Both the nucleoli and the chromatoid bodies disappeared in the sequential stages. Within the cytoplasm of such cells disintegration of a polysomal pattern was correlated with the disappearance of chromatoid bodies. The significance of the planarian chromatoid body is discussed in relation to differentiation of the regenerative cells.

  17. Long clinostation influence on the localization of free and weakly bound calcium in cell walls of Funaria hygrometrica moss protonema cells

    Science.gov (United States)

    Nedukha, E. M.

    The pyroantimonate method was used to study the localization of free and weakly bound calcium in cells of moss protonema of Funaria hygrometrica Hedw. cultivated on a clinostat (2 rev/min). Electroncytochemical study of control cells cultivated at 1 g revealed that granular precipitate marked chloroplasts, mitochondria, Golgi apparatus, lipid drops, nucleoplasma, nucleolus, nucleus membranes, cell walls and endoplasmic reticulum. In mitochondria the precipitate was revealed in stroma, in chloroplast it was found on thylakoids and envelope membranes. The cultivation of protonema on clinostat led to the intensification in cytochemical reaction product deposit. A considerable intensification of the reaction was noted in endomembranes, vacuoles, periplasmic space and cell walls. At the same time analysis of pectinase localization was made using the electroncytochemical method. A high reaction intensity in walls in comparison to that in control was found out to be a distinctive pecularity of the cells cultivated on clinostat. It testifies to the fact that increasing of freee calcium concentrations under conditions of clinostation is connected with pectinic substances hydrolysis and breaking of methoxy groups of pectins. Data obtained are discussed in relation to problems of possible mechanisms of disturbance in calcium balance of plant cells and the role of cell walls in gomeostasis of cell grown under conditions of simulated weighlessness.

  18. [Induced-division of neurons derived from neural stem cells].

    Science.gov (United States)

    Lin, Qiu-Xia; Que, Hai-Ping; Lu, Shuang-Hong; Liu, Shao-Jun

    2004-04-25

    In order to explore if mature neurons derived from neural stem cells have the potentiality to divide, we utilized the chemical digestion method to disperse the adult rat brain tissue into single cells, and culture them in serum-free medium. After being cultured for about eight days in vitro, the neural stem cells were induced to differentiate into neurons. The neurons were further induced to divide. Utilizing the method of serial photograph and NF-160 immunocytochemistry, the processes of division of some neurons were recorded. At the same time, PCNA+NF-160 (or Chat, GABA, GAD) double label were used to investigate if the dividing-neurons were mature ones. After the neural stem cells were induced to differentiate in vitro for eight days, they possessed the shape and character of mature neurons. The differentiated neuron had a big nucleus and one or two distinct nucleolus in the nuclear. Within the perikaryon,there were a large amount of dense and Nissl body-like structure. Several long processes emerged from various locations of the cell body. Then, EGF and bFGF were added into the medium to induce division. After two days of induced-division, neuron-like cells were observed to divide; moreover, the number of neuron-like cells in the region increased continually. Immunocytochemistry demonstrated these cells were NF-160-positive. Serial photographs of dividing-process of neuron-like cells were obtained and their daughter cells were also NF-160-positive. After PCNA+NF-160 (or Chat, GABA, GAD) double label, some cells showed brown cell plasma and black nucleus. The above-mentioned results indicate that neurons, which were previously thought to be end-differentiated, can be re-called into cell cycle under appropriate conditions. Mature neurons still have the potential to divide, proliferate and self-renew.

  19. Transient bursts of Zscan4 expression are accompanied by the rapid derepression of heterochromatin in mouse embryonic stem cells

    Science.gov (United States)

    Akiyama, Tomohiko; Xin, Li; Oda, Mayumi; Sharov, Alexei A.; Amano, Misa; Piao, Yulan; Cadet, J. Scotty; Dudekula, Dawood B.; Qian, Yong; Wang, Weidong; Ko, Shigeru B. H.; Ko, Minoru S. H.

    2015-01-01

    Mouse embryonic stem cells (mESCs) have a remarkable capacity to maintain normal genome stability and karyotype in culture. We previously showed that infrequent bursts of Zscan4 expression (Z4 events) are important for the maintenance of telomere length and genome stability in mESCs. However, the molecular details of Z4 events remain unclear. Here we show that Z4 events involve unexpected transcriptional derepression in heterochromatin regions that usually remain silent. During a Z4 event, we see rapid derepression and rerepression of heterochromatin leading to a burst of transcription that coincides with transient histone hyperacetylation and DNA demethylation, clustering of pericentromeric heterochromatin around the nucleolus, and accumulation of activating and repressive chromatin remodelling complexes. This heterochromatin-based transcriptional activity suggests that mESCs may maintain their extraordinary genome stability at least in part by transiently resetting their heterochromatin. PMID:26324425

  20. Microscopic Aspects of Autoschizic Cell Death in Human Ovarian Carcinoma (2774) Cells Following Vitamin C, Vitamin K3 or Vitamin C:K3 Treatment

    Science.gov (United States)

    Gilloteaux, Jacques; Jamison, James M.; Arnold, David; Taper, Henryk S.; von Gruenigen, Vivian E.; Summers, Jack L.

    2003-08-01

    Human ovarian carcinoma cells (MDAH 2774) were treated with sodium ascorbate (VC), menadione (VK3), or with a VC:VK3 combination for 1 h and then studied using light microscopy (LM) and scanning (SEM) and transmission electron (TEM) microscopy. Plasma membrane damage (blisters and blebs, hairy aspect) results from vitamin C (VC) treatment, while cytoskeletal damage and self-morsellation are caused by vitamin K3 (VK3) treatment. VC:VK3-treated cells exhibit exacerbated injuries characteristic of both VC and VK3 treatment as well as a significant decrease in cell diameters from 20 35 [mu]m for control cells to 7 12 [mu]m for VC:VK3 treatment. Moreover, after a 1-h exposure to the vitamin combination, autoschizis (43%), apoptosis (3%), and oncosis (1.9%) are observed at the percentages indicated. All cellular changes associated with autoschizis observed with SEM were confirmed by LM and TEM observations and are consistent with cell death by autoschizis: decrease in cell size, cytoplasmic self-excisions, degradation of the nucleus and nucleolus without formation of apoptotic bodies and, ultimately, karyorrhexis and karyolysis. These results also suggest that the vitamin combination may find clinical use in the treatment of ovarian cancer.

  1. A ribosomal protein L23-nucleophosmin circuit coordinates Miz1 function with cell growth

    DEFF Research Database (Denmark)

    Wanzel, Michael; Russ, Annika C; Kleine-Kohlbrecher, Daniela;

    2008-01-01

    The Myc-associated zinc-finger protein, Miz1, is a negative regulator of cell proliferation and induces expression of the cell-cycle inhibitors p15(Ink4b) and p21(Cip1). Here we identify the ribosomal protein L23 as a negative regulator of Miz1-dependent transactivation. L23 exerts this function ......, this regulatory circuit may provide a feedback mechanism that links translation of Myc target genes and cell growth to Miz1-dependent cell-cycle arrest.......The Myc-associated zinc-finger protein, Miz1, is a negative regulator of cell proliferation and induces expression of the cell-cycle inhibitors p15(Ink4b) and p21(Cip1). Here we identify the ribosomal protein L23 as a negative regulator of Miz1-dependent transactivation. L23 exerts this function...... by retaining nucleophosmin, an essential co-activator of Miz1 required for Miz1-induced cell-cycle arrest, in the nucleolus. Mutant forms of nucleophosmin found in acute myeloid leukaemia fail to co-activate Miz1 and re-localize it to the cytosol. As L23 is encoded by a direct target gene of Myc...

  2. Thymosin beta 4 may translocate from the cytoplasm in to the nucleus in HepG2 cells following serum starvation. An ultrastructural study.

    Science.gov (United States)

    Piludu, Marco; Piras, Monica; Pichiri, Giuseppina; Coni, Pierpaolo; Orrù, Germano; Cabras, Tiziana; Messana, Irene; Faa, Gavino; Castagnola, Massimo

    2015-01-01

    Due to its actin-sequestering properties, thymosin beta-4 (Tβ4) is considered to play a significant role in the cellular metabolism. Several physiological properties of Tβ4 have been reported;, however, many questions concerning its cellular function remain to be ascertained. To better understand the role of this small peptide we have analyzed by means of transmission immunoelectron microscopy techniques the ultrastructural localization of Tβ4 in HepG2 cells. Samples of HepG2 cells were fixed in a mixture of 3% formaldehyde and 0.1% glutaraldehyde in 0.1 M cacodylate buffer and processed for standard electron microscopic techniques. The samples were dehydrated in a cold graded methanol series and embedded in LR gold resin. Ultrathin sections were labeled with rabbit antibodies to Tβ4, followed by gold-labeled goat anti-rabbit, stained with uranyl acetate and bismuth subnitrate, observed and photographed in a JEOL 100S transmission electron microscope. High-resolution electron microscopy showed that Tβ4 was mainly restricted to the cytoplasm of HepG2 growing in complete medium. A strong Tβ4 reactivity was detected in the perinuclear region of the cytoplasmic compartment where gold particles appeared strictly associated to the nuclear membrane. In the nucleus specific Tβ4 labeling was observed in the nucleolus. The above electron microscopic results confirm and extend previous observations at light microscopic level, highlighting the subcellular distribution of Tβ4 in both cytoplasmic and nuclear compartments of HepG2 cells. The meaning of Tβ4 presence in the nucleolus is not on the best of our knowledge clarified yet. It could account for the interaction of Tβ4 with nucleolar actin and according with this hypothesis, Tβ4 could contribute together with the other nucleolar acting binding proteins to modulate the transcription activity of the RNA polymerases.

  3. Thymosin Beta 4 May Translocate from the Cytoplasm in to the Nucleus in HepG2 Cells following Serum Starvation. An Ultrastructural Study

    Science.gov (United States)

    Piludu, Marco; Piras, Monica; Pichiri, Giuseppina; Coni, Pierpaolo; Orrù, Germano; Cabras, Tiziana; Messana, Irene; Faa, Gavino; Castagnola, Massimo

    2015-01-01

    Due to its actin-sequestering properties, thymosin beta-4 (Tβ4) is considered to play a significant role in the cellular metabolism. Several physiological properties of Tβ4 have been reported;, however, many questions concerning its cellular function remain to be ascertained. To better understand the role of this small peptide we have analyzed by means of transmission immunoelectron microscopy techniques the ultrastructural localization of Tβ4 in HepG2 cells. Samples of HepG2 cells were fixed in a mixture of 3% formaldehyde and 0.1% glutaraldehyde in 0.1 M cacodylate buffer and processed for standard electron microscopic techniques. The samples were dehydrated in a cold graded methanol series and embedded in LR gold resin. Ultrathin sections were labeled with rabbit antibodies to Tβ4, followed by gold-labeled goat anti-rabbit, stained with uranyl acetate and bismuth subnitrate, observed and photographed in a JEOL 100S transmission electron microscope. High-resolution electron microscopy showed that Tβ4 was mainly restricted to the cytoplasm of HepG2 growing in complete medium. A strong Tβ4 reactivity was detected in the perinuclear region of the cytoplasmic compartment where gold particles appeared strictly associated to the nuclear membrane. In the nucleus specific Tβ4 labeling was observed in the nucleolus. The above electron microscopic results confirm and extend previous observations at light microscopic level, highlighting the subcellular distribution of Tβ4 in both cytoplasmic and nuclear compartments of HepG2 cells. The meaning of Tβ4 presence in the nucleolus is not on the best of our knowledge clarified yet. It could account for the interaction of Tβ4 with nucleolar actin and according with this hypothesis, Tβ4 could contribute together with the other nucleolar acting binding proteins to modulate the transcription activity of the RNA polymerases. PMID:25835495

  4. Nucleolin on the cell surface as a new molecular target for gastric cancer treatment.

    Science.gov (United States)

    Watanabe, Tatsuro; Hirano, Kazuya; Takahashi, Atsushi; Yamaguchi, Kensei; Beppu, Masatoshi; Fujiki, Hirota; Suganuma, Masami

    2010-01-01

    Nucleolin is an abundant non-ribosomal protein found in nucleolus and a major component of silver-stained nucleolar organizer region (AgNOR), a histopathological marker of cancer which is highly elevated in cancer cells. We recently reported that nucleolin on the cell surface of mouse gastric cancer cells acts as a receptor for tumor necrosis factor-alpha-inducing protein (Tipalpha), a new carcinogenic factor of Helicobacter pylori. In this study, we first examined the localization of nucleolin on cell surface of five gastric cancer cell lines by cell fractionation and flow cytometry: We found that large amounts of nucleolin were present on surface of MKN-45, KATOIII, MKN-74, and AGS cells, with smaller amounts on surface of MKN-1 cells. The membrane fraction of normal epithelial cells of mouse glandular stomach did not contain much nucleolin, suggesting that translocation of nucleolin to the cell surface occurs during carcinogenesis, making for easier binding with Tipalpha. AS1411, a nucleolin targeted DNA aptamer, inhibited growth of gastric cancer cell lines in this order of potency: MKN-45>KATOIII>AGS>MKN-74=MKN-1, associated with induction of S-phase cell cycle arrest. Fluorescein isothiocyanate (FITC)-AS1411 was more rapidly incorporated into MKN-45 and AGS than into MKN-1 cells, based on varying amounts of cell surface nucleolin. We think that AS1411 first binds to nucleolin on the cell surface and that the binding complex is then incorporated into the cells. All results indicate that nucleolin on the cell surface is a new and promising therapeutic target for treatment of gastric cancer.

  5. ELECTRON MICROSCOPIC AUTORADIOGRAPHIC STUDY ON SUBCELLULAR LOCALIZATION OF FISSION PRODUCT 147Pm IN TISSUE CELLS

    Institute of Scientific and Technical Information of China (English)

    朱寿彭; 汪源长

    1994-01-01

    The early risk of internal contaminated accumualtion of 147Pm is in blood cells and endothelial cells,especially in red blood cells.Then 147Pm is selectively deposited in ultrastructure of liver cells,such as in nucleus,nucleolus,rough endoplasmic reticulum,mitochondria and microbodies,Dense tracks also appear in mitochondria and lysosome of pedal cells within renal corpuscle,and so dose in nucleus as well as in mitochondria and microbodies of epicyte of kidney near-convoluted tubule.With the prolongation of observing time,147Pm is selectively and steadily depostied in subcellular level of organic ocmponent for bone.Substantial amount of 147Pm is taken up into the nuclear fraction of osteoclasts and osteoblasts.Particularly,in organelles 147Pm is mainly accumulated in rough endoplasmic reticulum and in mitochondria.Autoradiographic tracks especially localize in combined point between Golgi complex and transitive vesicle of rough endoplasmic reticulum.In addition,numerous 147Pm deposited in collagenous fibre within interstitial of bone cells is hardly excreted.

  6. Different intracellular distribution of avian reovirus core protein sigmaA in cells of avian and mammalian origin

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez-Iglesias, Lorena; Lostale-Seijo, Irene; Martinez-Costas, Jose [Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, y Centro Singular de Investigacion en Quimica Biologica y Materiales Moleculares (CIQUS), Universidad de Santiago de Compostela, 15782-Santiago de Compostela (Spain); Benavente, Javier, E-mail: franciscojavier.benavente@usc.es [Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, y Centro Singular de Investigacion en Quimica Biologica y Materiales Moleculares (CIQUS), Universidad de Santiago de Compostela, 15782-Santiago de Compostela (Spain)

    2012-10-25

    A comparative analysis of the intracellular distribution of avian reovirus (ARV) core protein sigmaA in cells of avian and mammalian origin revealed that, whereas the viral protein accumulates in the cytoplasm and nucleolus of avian cells, most sigmaA concentrates in the nucleoplasm of mammalian cells in tight association with the insoluble nuclear matrix fraction. Our results further showed that sigmaA becomes arrested in the nucleoplasm of mammalian cells via association with mammalian cell-specific factors and that this association prevents nucleolar targeting. Inhibition of RNA polymerase II activity, but not of RNA polymerase I activity, in infected mammalian cells induces nucleus-to-cytoplasm sigmaA translocation through a CRM1- and RanGTP-dependent mechanism, yet a heterokaryon assay suggests that sigmaA does not shuttle between the nucleus and cytoplasm. The scarcity of sigmaA in cytoplasmic viral factories of infected mammalian cells could be one of the factors contributing to limited ARV replication in mammalian cells.

  7. A cell cycle role for the epigenetic factor CTCF-L/BORIS.

    Directory of Open Access Journals (Sweden)

    Manuel Rosa-Garrido

    Full Text Available CTCF is a ubiquitous epigenetic regulator that has been proposed as a master keeper of chromatin organisation. CTCF-like, or BORIS, is thought to antagonise CTCF and has been found in normal testis, ovary and a large variety of tumour cells. The cellular function of BORIS remains intriguing although it might be involved in developmental reprogramming of gene expression patterns. We here unravel the expression of CTCF and BORIS proteins throughout human epidermis. While CTCF is widely distributed within the nucleus, BORIS is confined to the nucleolus and other euchromatin domains. Nascent RNA experiments in primary keratinocytes revealed that endogenous BORIS is present in active transcription sites. Interestingly, BORIS also localises to interphase centrosomes suggesting a role in the cell cycle. Blocking the cell cycle at S phase or mitosis, or causing DNA damage, produced a striking accumulation of BORIS. Consistently, ectopic expression of wild type or GFP- BORIS provoked a higher rate of S phase cells as well as genomic instability by mitosis failure. Furthermore, down-regulation of endogenous BORIS by specific shRNAs inhibited both RNA transcription and cell cycle progression. The results altogether suggest a role for BORIS in coordinating S phase events with mitosis.

  8. Perinucleolar relocalization and nucleolin as crucial events in the transcriptional activation of key genes in mantle cell lymphoma.

    Science.gov (United States)

    Allinne, Jeanne; Pichugin, Andrei; Iarovaia, Olga; Klibi, Manel; Barat, Ana; Zlotek-Zlotkiewicz, Ewa; Markozashvili, Diana; Petrova, Natalia; Camara-Clayette, Valérie; Ioudinkova, Elena; Wiels, Joëlle; Razin, Sergey V; Ribrag, Vincent; Lipinski, Marc; Vassetzky, Yegor S

    2014-03-27

    In mantle cell lymphoma (MCL), one allele of the cyclin D1 (Ccnd1) gene is translocated from its normal localization on chromosome 11 to chromosome 14. This is considered as the crucial event in the transformation process of a normal naive B-cell; however, the actual molecular mechanism leading to Ccnd1 activation remains to be deciphered. Using a combination of three-dimensional and immuno-fluorescence in situ hybridization experiments, the radial position of the 2 Ccnd1 alleles was investigated in MCL-derived cell lines and malignant cells from affected patients. The translocated Ccnd1 allele was observed significantly more distant from the nuclear membrane than its nontranslocated counterpart, with a very high proportion of IgH-Ccnd1 chromosomal segments localized next to a nucleolus. These perinucleolar areas were found to contain active RNA polymerase II (PolII) clusters. Nucleoli are rich in nucleolin, a potent transcription factor that we found to bind sites within the Ccnd1 gene specifically in MCL cells and to activate Ccnd1 transcription. We propose that the Ccnd1 transcriptional activation in MCL cells relates to the repositioning of the rearranged IgH-Ccnd1-carrying chromosomal segment in a nuclear territory with abundant nucleolin and active PolII molecules. Similar transforming events could occur in Burkitt and other B-cell lymphomas.

  9. Cucurbitacin B inhibits human breast cancer cell proliferation through disruption of microtubule polymerization and nucleophosmin/B23 translocation

    Directory of Open Access Journals (Sweden)

    Duangmano Suwit

    2012-10-01

    Full Text Available Abstract Background Cucurbitacin B, an oxygenated tetracyclic triterpenoid compound extracted from the Thai medicinal plant Trichosanthes cucumerina L., has been reported to have several biological activities including anti-inflammatory, antimicrobial and anticancer. Cucurbitacin B is great of interest because of its biological activity. This agent inhibits growth of various types of human cancer cells lines. Methods In this study, we explored the novel molecular response of cucurbitacin B in human breast cancer cells, MCF-7 and MDA-MB-231. The growth inhibitory effect of cucurbitacin B on breast cancer cells was assessed by MTT assay. The effects of cucurbitacin B on microtubules morphological structure and tubulin polymerization were analyzed using immunofluorescence technique and tubulin polymerization assay kit, respectively. Proteomic analysis was used to identify the target-specific proteins that involved in cucurbitacin B treatment. Some of the differentially expressed genes and protein products were validated by real-time RT-PCR and western blot analysis. Cell cycle distributions and apoptosis were investigated using flow cytometry. Results Cucurbitacin B exhibited strong antiproliferative effects against breast cancer cells in a dose-dependent manner. We show that cucurbitacin B prominently alters the cytoskeletal network of breast cancer cells, inducing rapid morphologic changes and improper polymerization of the microtubule network. Moreover, the results of 2D-PAGE, real-time RT-PCR, and western blot analysis revealed that the expression of nucleophosmin/B23 and c-Myc decreased markedly after cucurbitacin B treatment. Immunofluorescence microscopy showed that cucurbitacin B induced translocation of nucleophosmin/B23 from the nucleolus to nucleoplasm. Treatment with cucurbitacin B resulted in cell cycle arrest at G2/M phase and the enhancement of apoptosis. Conclusions Our findings suggest that cucurbitacin B may inhibit the

  10. Development of a randomized 3D cell model for Monte Carlo microdosimetry simulations

    Energy Technology Data Exchange (ETDEWEB)

    Douglass, Michael; Bezak, Eva; Penfold, Scott [School of Chemistry and Physics, University of Adelaide, North Terrace, Adelaide 5005, South Australia (Australia) and Department of Medical Physics, Royal Adelaide Hospital, North Terrace, Adelaide 5000, South Australia (Australia)

    2012-06-15

    Purpose: The objective of the current work was to develop an algorithm for growing a macroscopic tumor volume from individual randomized quasi-realistic cells. The major physical and chemical components of the cell need to be modeled. It is intended to import the tumor volume into GEANT4 (and potentially other Monte Carlo packages) to simulate ionization events within the cell regions. Methods: A MATLAB Copyright-Sign code was developed to produce a tumor coordinate system consisting of individual ellipsoidal cells randomized in their spatial coordinates, sizes, and rotations. An eigenvalue method using a mathematical equation to represent individual cells was used to detect overlapping cells. GEANT4 code was then developed to import the coordinate system into GEANT4 and populate it with individual cells of varying sizes and composed of the membrane, cytoplasm, reticulum, nucleus, and nucleolus. Each region is composed of chemically realistic materials. Results: The in-house developed MATLAB Copyright-Sign code was able to grow semi-realistic cell distributions ({approx}2 Multiplication-Sign 10{sup 8} cells in 1 cm{sup 3}) in under 36 h. The cell distribution can be used in any number of Monte Carlo particle tracking toolkits including GEANT4, which has been demonstrated in this work. Conclusions: Using the cell distribution and GEANT4, the authors were able to simulate ionization events in the individual cell components resulting from 80 keV gamma radiation (the code is applicable to other particles and a wide range of energies). This virtual microdosimetry tool will allow for a more complete picture of cell damage to be developed.

  11. Differentiations of transplanted mouse spermatogonial stem cells in the adult mouse renal parenchyma in vivo

    Institute of Scientific and Technical Information of China (English)

    Da-peng WU; Da-lin HE; Xiang LI; Zhao-hui LIU

    2008-01-01

    Aim:Spermatogonial stem cells can initiate the process of cellular differentia-tion to generate mature spermatozoa, but whether it possess the characteristic of pluripotency and plasticity, similar to embryonic stem cells, has not been elucidated. This study was designed to evaluate the differentiation potential of spermatogonial stem cells into renal cells in vivo. Methods: Neonatal mouse spermatogonial stem cells were transplanted into mature male mice lacking en-dogenous spermatogenesis. The restoration of fertility in recipient males was observed. Spermatogonial stem cells were then injected into renal parenchyma of mature female mice to make a new extracellular environment for differentia-tion. Fluorescence in situ hybridization technology (FISH) was used to detect the expression of chromosome Y in recipient renal tissues. To determine the type of cells differentiated from spermatogonial stem cells, the expression of ricinus communis agglutinin, vimentin, CD45, and F4/80 proteins were examined in the renal tissues by immunohistochemistry. Results: The proliferation of seminiferous epithelial cells was distinctly observed in seminiferous tubules of transplanted testes, whereas no regeneration of spermatogenesis was observed in non-transplanted control testes. In transplanted female renal tissues, FISH showed a much stronger immuno-fluorescence signal of chromosome Y in the nucleolus of epithelial cells of the renal tubule and podocytes of the glomerulus. Conclusion: The spermatogonial stem cells were successfully purified from mouse testicles. This finding demonstrated that spermatogonial stem cells could not only restore damaged spermatogenesis, but were also capable of differentiat-ing into mature renal parenchyma cells in vivo.

  12. Upregulated expression of Ezrin and invasive phenotype in malignantly transformed esophageal epithelial cells

    Institute of Scientific and Technical Information of China (English)

    Zhong-Ying Shen; Li-Yan Xu; Ming-Hua Chen; En-Min Li; Jin-Tao Li; Xian-Ying Wu; Yi Zeng

    2003-01-01

    AIM: To investigate the correlation between ezrin expression and invasive phenotype formation in malignantly transformed esophageal epithelial cells. METHODS: The experimental cell line employed in the present study was originated form the progressive induction of a human embryonic esophageal epithelial cell line (SHEE)by the E6E7 genes of human papillomavirus (HPV) type 18.The cells at the 35th passage after induction called SHEEIMM were in a state of immortalized phase and used as the control,while that of the 85th passage denominated as SHEEMT represented the status of cells that were malignantly transformed. The expression changes of ezrin and its mRNA in both cell passages were respectively analyzed by RT-PCR and Western blot. Invasive phenotype was assessed in vivo by inoculating these cells into the severe combined immunodeficient (SCID) mice via subcutaneous and intraperitoneal injection, and in vitro by inoculating them on the surface of the amnion membranes, which then was determined by light microscopy and scanning electron microscopy. RESULTS: Upregulated expression of ezrin protein and its mRNA was observed in SHEEMT compared with that in SHEEIMM cells. The SHEEMT cells inoculated in SCID mice were observed forming tumor masses in both visceral organs and soft tissues in a period of 40 days with a special propensity to invading mesentery and pancreas, but did not exhibit hepatic metastases. Pathologically, these tumor cells harboring larger nucleus, nucleolus and less cytoplasm could infiltrate and destroy adjacent tissues. In the in vitro study,the inoculated SHEEMT cells could grow in cluster on the amniotic epithelial surface and intrude into the amniotic stroma. In contrast, unrestricted growth and invasiveness were not found in SHEEIMM cells in both in vivo and in vitroexperiment. CONCLUSION: The upregulated ezrin expression is one of the important factors that are possibly associated with the invasive phenotype formation in malignantly

  13. Preparation of nano-hydroxyapatite particles with different morphology and their response to highly malignant melanoma cells in vitro

    Science.gov (United States)

    Li, Bo; Guo, Bo; Fan, Hongsong; Zhang, Xingdong

    2008-11-01

    To investigate the effects of nano-hydroxyapatite (HA) particles with different morphology on highly malignant melanoma cells, three kinds of HA particles with different morphology were synthesized and co-cultured with highly malignant melanoma cells using phosphate-buffered saline (PBS) as control. A precipitation method with or without citric acid addition as surfactant was used to produce rod-like hydroxyapatite (HA) particles with nano- and micron size, respectively, and a novel oil-in-water emulsion method was employed to prepare ellipse-like nano-HA particles. Particle morphology and size distribution of the as prepared HA powders were characterized by transmission electron microscope (TEM) and dynamic light scattering technique. The nano- and micron HA particles with different morphology were co-cultured with highly malignant melanoma cells. Immunofluorescence analysis and MTT assay were employed to evaluate morphological change of nucleolus and proliferation of tumour cells, respectively. To compare the effects of HA particles on cell response, the PBS without HA particles was used as control. The experiment results indicated that particle nanoscale effect rather than particle morphology of HA was more effective for the inhibition on highly malignant melanoma cells proliferation.

  14. Preparation of nano-hydroxyapatite particles with different morphology and their response to highly malignant melanoma cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Li Bo [National Engineering Research Center for Biomaterial, Sichuan University, Chengdu 610064 (China); Guo Bo [National Engineering Research Center for Biomaterial, Sichuan University, Chengdu 610064 (China); West China Eye Center of Huaxi Hospital, Sichuan University, Chengdu 610064 (China); Fan Hongsong [National Engineering Research Center for Biomaterial, Sichuan University, Chengdu 610064 (China)], E-mail: leewave@126.com; Zhang Xingdong [National Engineering Research Center for Biomaterial, Sichuan University, Chengdu 610064 (China)

    2008-11-15

    To investigate the effects of nano-hydroxyapatite (HA) particles with different morphology on highly malignant melanoma cells, three kinds of HA particles with different morphology were synthesized and co-cultured with highly malignant melanoma cells using phosphate-buffered saline (PBS) as control. A precipitation method with or without citric acid addition as surfactant was used to produce rod-like hydroxyapatite (HA) particles with nano- and micron size, respectively, and a novel oil-in-water emulsion method was employed to prepare ellipse-like nano-HA particles. Particle morphology and size distribution of the as prepared HA powders were characterized by transmission electron microscope (TEM) and dynamic light scattering technique. The nano- and micron HA particles with different morphology were co-cultured with highly malignant melanoma cells. Immunofluorescence analysis and MTT assay were employed to evaluate morphological change of nucleolus and proliferation of tumour cells, respectively. To compare the effects of HA particles on cell response, the PBS without HA particles was used as control. The experiment results indicated that particle nanoscale effect rather than particle morphology of HA was more effective for the inhibition on highly malignant melanoma cells proliferation.

  15. X-ray microimaging of cisplatin distribution in ovarian cancer cells

    Science.gov (United States)

    Kiyozuka, Yasuhiko; Takemoto, Kuniko; Yamamoto, Akitsugu; Guttmann, Peter; Tsubura, Airo; Kihara, Hiroshi

    2000-05-01

    X-ray microscopy has the possibility to be in use for elemental analysis of tissue and cells especially under physiological conditions with high lateral resolution. In X-ray microimaging cisdiamminedichloroplatinum II (cisplatin: CDDP), an anticancer agent, which has a platinum atom at its functional center gives sufficient contrast against organic material at sub-cellular level. We analyzed the enhance effect and intracellular distribution of CDDP in human ovarian cancer cells with the transmission X-ray microscope at BESSY, Berlin. Two human ovarian cancer cell lines (MN-1 and EC) were treated with 1 and 10 μg/ml of CDDP for 4 hours and compared with untreated cells X-ray images of CDDP-treated samples show clearly labeled nucleoli, periphery of the nucleus and mitochondria, in a concentration-dependent manner. CDDP binds to DNA molecules via the formation of intra- or-inter-strand cross-links. Higher contrasts at the periphery of nucleus and nucleoli suggest the distribution of tightly packed heterochromatin. In addition, results show the possibility that CDDP binds to mitochondrial DNA. Biological function of cisplatin is not only the inhibition of DNA replication but is suggested to disturb mitochondrial function and RNA synthesis in the nucleolus.

  16. Quantitative 3D imaging of whole, unstained cells by using X-ray diffraction microscopy.

    Science.gov (United States)

    Jiang, Huaidong; Song, Changyong; Chen, Chien-Chun; Xu, Rui; Raines, Kevin S; Fahimian, Benjamin P; Lu, Chien-Hung; Lee, Ting-Kuo; Nakashima, Akio; Urano, Jun; Ishikawa, Tetsuya; Tamanoi, Fuyuhiko; Miao, Jianwei

    2010-06-22

    Microscopy has greatly advanced our understanding of biology. Although significant progress has recently been made in optical microscopy to break the diffraction-limit barrier, reliance of such techniques on fluorescent labeling technologies prohibits quantitative 3D imaging of the entire contents of cells. Cryoelectron microscopy can image pleomorphic structures at a resolution of 3-5 nm, but is only applicable to thin or sectioned specimens. Here, we report quantitative 3D imaging of a whole, unstained cell at a resolution of 50-60 nm by X-ray diffraction microscopy. We identified the 3D morphology and structure of cellular organelles including cell wall, vacuole, endoplasmic reticulum, mitochondria, granules, nucleus, and nucleolus inside a yeast spore cell. Furthermore, we observed a 3D structure protruding from the reconstructed yeast spore, suggesting the spore germination process. Using cryogenic technologies, a 3D resolution of 5-10 nm should be achievable by X-ray diffraction microscopy. This work hence paves a way for quantitative 3D imaging of a wide range of biological specimens at nanometer-scale resolutions that are too thick for electron microscopy.

  17. Identification of p53 and Its Isoforms in Human Breast Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Zorka Milićević

    2014-01-01

    Full Text Available In breast carcinoma, disruption of the p53 pathway is one of the most common genetic alterations. The observation that the p53 can express multiple protein isoforms adds a novel level of complexity to the outcome of p53 mutations. p53 expression was analysed by Western immunoblotting and immunohistochemistry using monoclonal antibodies DO-7, Pab240, and polyclonal antiserum CM-1. The more frequently p53-positive nuclear staining has been found in the invasive breast tumors. One of the most intriguing findings is that mutant p53 appears as discrete dot-shaped regions within the nucleus of breast cancer cells. In many malignant cells, the nucleolar sequestration of p53 is evident. These observations support the view that the nucleolus is involved directly in the mediation of p53 function or indirectly by the control of the localization of p53 interplayers. p53 expressed in the nuclear fraction of breast cancer cells revealed a wide spectrum of isoforms. p53 isoforms ΔNp53 (47 kDa and Δ133p53β (35 kDa, known as dominant-negative repressors of p53 function, were detected as the most predominant variants in nuclei of invasive breast carcinoma cells. The isoforms expressed also varied between individual tumors, indicating potential roles of these p53 variants in human breast cancer.

  18. Dyskerin localizes to the mitotic apparatus and is required for orderly mitosis in human cells.

    Directory of Open Access Journals (Sweden)

    Faizan Alawi

    Full Text Available Dyskerin is a highly conserved, nucleolar RNA-binding protein with established roles in small nuclear ribonucleoprotein biogenesis, telomerase and telomere maintenance and precursor rRNA processing. Telomerase is functional during S phase and the bulk of rRNA maturation occurs during G1 and S phases; both processes are inactivated during mitosis. Yet, we show that during the course of cell cycle progression, human dyskerin expression peaks during G2/M in parallel with the upregulation of pro-mitotic factors. Dyskerin redistributed from the nucleolus in interphase cells to the perichromosomal region during prometaphase, metaphase and anaphase. With continued anaphase progression, dyskerin also localized to the cytoplasm within the mid-pole region. Loss of dyskerin function via siRNA-mediated depletion promoted G2/M accumulation and this was accompanied by an increased mitotic index and activation of the spindle assembly checkpoint. Live cell imaging further revealed an array of mitotic defects including delayed prometaphase progression, a significantly increased incidence of multi-polar spindles, and anaphase bridges culminating in micronucleus formation. Together, these findings suggest that dyskerin is a highly dynamic protein throughout the cell cycle and increases the repertoire of fundamental cellular processes that are disrupted by absence of its normal function.

  19. Dyskerin localizes to the mitotic apparatus and is required for orderly mitosis in human cells.

    Science.gov (United States)

    Alawi, Faizan; Lin, Ping

    2013-01-01

    Dyskerin is a highly conserved, nucleolar RNA-binding protein with established roles in small nuclear ribonucleoprotein biogenesis, telomerase and telomere maintenance and precursor rRNA processing. Telomerase is functional during S phase and the bulk of rRNA maturation occurs during G1 and S phases; both processes are inactivated during mitosis. Yet, we show that during the course of cell cycle progression, human dyskerin expression peaks during G2/M in parallel with the upregulation of pro-mitotic factors. Dyskerin redistributed from the nucleolus in interphase cells to the perichromosomal region during prometaphase, metaphase and anaphase. With continued anaphase progression, dyskerin also localized to the cytoplasm within the mid-pole region. Loss of dyskerin function via siRNA-mediated depletion promoted G2/M accumulation and this was accompanied by an increased mitotic index and activation of the spindle assembly checkpoint. Live cell imaging further revealed an array of mitotic defects including delayed prometaphase progression, a significantly increased incidence of multi-polar spindles, and anaphase bridges culminating in micronucleus formation. Together, these findings suggest that dyskerin is a highly dynamic protein throughout the cell cycle and increases the repertoire of fundamental cellular processes that are disrupted by absence of its normal function.

  20. Ultrastructure of human neural stem/progenitor cells and neurospheres

    Institute of Scientific and Technical Information of China (English)

    Yaodong Zhao; Tianyi Zhang; Qiang Huang; Aidong Wang; Jun Dong; Qing Lan; Zhenghong Qin

    2009-01-01

    BACKGROUND: Biological and morphological characteristics of neural stern/progenitor cells (NSPCs) have been widely investigated.OBJECTIVE: To explore the ultrastructure of human embryo-derived NSPCs and neurospheres cultivated in vitro using electron microscopy.DESIGN, TIME AND SETTING: A cell biology experiment was performed at the Brain Tumor Laboratory of Soochow University, and Jiangsu Province Key Laboratory of Neuroregeneration, Nantong University between August 2007 and April 2008.MATERIALS: Human fetal brain tissue was obtained from an 8-week-old aborted fetus; serum-free Dulbecco's modified Eagle's medium/F12 culture medium was provided by Gibco, USA; scanning electron microscope was provided by Hitachi instruments, Japan; transmission electron microscope was provided by JEOL, Japan.METHODS: NSPCs were isolated from human fetal brain tissue and cultivated in serum-free Dulbecco's modified Eagle's medium/F12 culture medium. Cells were passaged every 5-7 days. After three passages, NSPCs were harvested and used for ultrastructural examination.MAIN OUTCOME MEASURES: Ultrastructural examination of human NSPCs and adjacent cells in neurospheres.RESULTS: Individual NSPCs were visible as spherical morphologies with rough surfaces under scanning electron microscope. Generally, they had large nuclei and little cytoplasm. Nuclei were frequently globular with large amounts of euchromatin and a small quantity of heterochromatin, and most NSPCs had only one nucleolus. The Golgi apparatus and endoplasmic reticulum were underdeveloped; however, autophagosomes were clearly visible. The neurospheres were made up of NSPCs and non-fixiform material inside. Between adjacent cells and at the cytoplasmic surface of apposed plasma membranes, there were vesicle-like structures. Some membrane boundaries with high permeabilities were observed between some contiguous NSPCs in neurospheres, possibly attributable to plasmalemmal fusion between adjacent cells.CONCLUSION: A large number

  1. Genetic stability of murine pluripotent and somatic hybrid cells may be affected by conditions of their cultivation.

    Science.gov (United States)

    Ivanovna, Shramova Elena; Alekseevich, Larionov Oleg; Mikhailovich, Khodarovich Yurii; Vladimirovna, Zatsepina Olga

    2011-01-01

    Using mouse pluripotent teratocarcinoma PCC4azal cells and proliferating spleen lymphocytes we obtained a new type of hybrids, in which marker lymphocyte genes were suppressed, but expression the Oct-4 gene was not effected; the hybrid cells were able to differentiate to cardiomyocytes. In order to specify the environmental factors which may affect the genetic stability and other hybrid properties, we analyzed the total chromosome number and differentiation potencies of hybrids respectively to conditions of their cultivation. Particular attention was paid to the number and transcription activity of chromosomal nucleolus organizing regions (NORs), which harbor the most actively transcribed - ribosomal - genes. The results showed that the hybrids obtained are characterized by a relatively stable chromosome number which diminished less than in 5% during 27 passages. However, a long-term cultivation of hybrid cells in non-selective conditions resulted in preferential elimination of some NO- chromosomes, whereas the number of active NORs per cell was increased due to activation of latent NORs. On the contrary, in selective conditions, i.e. in the presence of hypoxantine, aminopterin and thymidine, the total number of NOR-bearing chromosomes was not changed, but a partial inactivation of remaining NORs was observed. The higher number of active NORs directly correlated with the capability of hybrid cells for differentiation to cardiomyocytes.

  2. Documentation of normal and leukemic myelopoietic progenitor cells with high-resolution phase-contrast time-lapse cinematography.

    Science.gov (United States)

    Boll, I T

    2001-08-01

    The high-resolution phase-contrast, time-lapse cinematography using oil immersion lenses and 16-mm film demonstrates the kinetic cell events as maturation, locomotion, mitosis, and apoptosis of cells cultivated at 37 degrees C for up to 10 days. 0.5 v/v frozen-thawed sera with presumably high cytokine concentrations were added to the plasma or agar clot. Vital progenitor cells from human bone marrow and blood have a large, bright, unstructured nucleus with a large nucleolus and a narrow rim of cytoplasm (nuclear/cytoplasmic volume ratio = 0.7). Their nuclei are 6-14 micrometer in diameter and double their volume within 8 h. Many (70%) move at a mean speed of 2 micrometer/min, and many (30%) multiply with alpha-2alpha mitoses, generating progenitor cell families. Various disturbances during the course of mitosis lead to the formation of polyploid cells, thereby yielding the megakaryocytic cell line. Some of the progenitor cells undergo asymmetric alpha-alphan mitoses: One of the two initially identical daughter cells remains a progenitor cell in the morphological sense, whereas the other daughter cell - depending on the size of its mother cell - matures in the same culture medium to form a granulocytopoietic, monocytopoietic or erythrocytopoietic cell line. - In acute myeloid leukemias (AML), the blasts and their nuclei are slightly larger than the corresponding progenitor cells and move faster (5 micrometer/min). Symmetric alpha-2alpha mitoses permit unlimited multiplication of the leukemic blasts if contact with cytotoxic lymphocytes does not render them apoptotic. This results in more stromal cells than normal. Granulocytopenia, monocytopenia, and anemia occur due to the genetic impairment of signaling control for asymmetric alpha-alphan mitoses, and thrombocytopenia occurs due to the reduction in polyploidization.

  3. Origin of Microcells in the Human Sarcoma Cell Line HT-1080

    Directory of Open Access Journals (Sweden)

    Indulis Buiķis

    1999-01-01

    Full Text Available The aim of this study was to investigate the development of microcells in the human sarcoma cell line HT‐1080 after interference with thiophosphamidum. We found that damaged interphase macrocells located at the projection of the nucleolus may form one or several microcells. The micronuclei of the microcells intensively incorporate the thymidine analogue 5‐bromo‐2'‐deoxyuridine and strongly express argyrophilic nucleolar organiser region proteins. At an early phase of the development, the micronuclei contain fragmented DNA, but in subsequent phases, the micronuclei accumulate polymeric DNA, simultaneously with an increase in their size. After desintegration of the damaged macrocell, the microcells appear in the intercellular space. The microcells can enter mitosis and they strongly express the lung resistance protein. Electron microscopic observations suggest that coiled bodies are involved in the development of the microcells. Since the observed path of microcell formation differs from apoptotic cell fragmentation into apoptotic bodies, we propose a new term for this microcell development: sporosis. We suggest that self‐renewal of the tumour stem cells is likely based on sporosis.

  4. DNA topoisomerase II-dependent control of the cell cycle progression in root meristems of Allium cepa.

    Science.gov (United States)

    Zabka, Aneta; Polit, Justyna Teresa; Bernasińska, Joanna; Maszewski, Janusz

    2014-03-01

    The catalytic ability of DNA topoisomerases (Topo) to generate short-term DNA breaks allow these enzymes to play crucial functions in managing DNA topology during S-phase replication, transcription, and chromatin-remodelling processes required to achieve commitment for the onset and transition through mitosis. Our experiments on root meristem cells of onion (Allium cepa) were designed to gain insight into the contribution of Topo II to plant-specific progression throughout interphase and mitosis. Irrespective of the position of the cell in interphase, the immunofluorescence of Topo II revealed similar nuclear labelling pattern with well defined signals dispersed in the nucleoplasm and the cortical zone of the nucleolus. Only weak labelling was detected in metaphase and anaphase chromosomes. Experiments with two potent anti-Topo II agents, doxorubicin (DOX, an anthracycline) and a bisdioxopiperazine derivative, ICRF-193, suggest that the inhibition-mediated increase in Topo II immunofluorescence may represent a compensatory mechanism, by which an up-regulated expression of the enzyme tends to counteract the drug-induced loss of indispensable catalytic and relaxation functions. γ-H2AX immunolabelling seems to indicate that both DOX- and ICRF-193-induced alterations in cell cycle progression reflect primarily the activity of the G2/M DNA damage checkpoint. Our findings provide evidence for the plant-specific cell cycle control mechanism induced by Topo II inhibitors under DNA stress conditions.

  5. Proper selection of 1 g controls in simulated microgravity research as illustrated with clinorotated plant cell suspension cultures

    Science.gov (United States)

    Kamal, Khaled Y.; Hemmersbach, Ruth; Medina, F. Javier; Herranz, Raúl

    2015-04-01

    Understanding the physical and biological effects of the absence of gravity is necessary to conduct operations on space environments. It has been previously shown that the microgravity environment induces the dissociation of cell proliferation from cell growth in young seedling root meristems, but this source material is limited to few cells in each row of meristematic layers. Plant cell cultures, composed by a large and homogeneous population of proliferating cells, are an ideal model to study the effects of altered gravity on cellular mechanisms regulating cell proliferation and associated cell growth. Cell suspension cultures of Arabidopsis thaliana cell line (MM2d) were exposed to 2D-clinorotation in a pipette clinostat for 3.5 or 14 h, respectively, and were then processed either by quick freezing, to be used in flow cytometry, or by chemical fixation, for microscopy techniques. After long-term clinorotation, the proportion of cells in G1 phase was increased and the nucleolus area, as revealed by immunofluorescence staining with anti-nucleolin, was decreased. Despite the compatibility of these results with those obtained in real microgravity on seedling meristems, we provide a technical discussion in the context of clinorotation and proper 1 g controls with respect to suspension cultures. Standard 1 g procedure of sustaining the cell suspension is achieved by continuously shaking. Thus, we compare the mechanical forces acting on cells in clinorotated samples, in a control static sample and in the standard 1 g conditions of suspension cultures in order to define the conditions of a complete and reliable experiment in simulated microgravity with corresponding 1 g controls.

  6. Function of oval cells in hepatocellular carcinoma in rats

    Institute of Scientific and Technical Information of China (English)

    Chi-Hua Fang; Jia-Qing Gong; Wei Zhang

    2004-01-01

    AIM: To study oval cells' pathological characteristics and relationship with the occurrence of hepatocellular carcinoma (HCC); to observe the form and structural characteristics of oval cells; to explore the expression characteristics of C-kit, PCNA mRNA and c-myc gene during the occurrence and development of HCC and the effect of ulinastatin (UTI) on C-kit and PCNA expression.METHODS: One hundred and twenty-five SD rats fed on 3,3'-diaminobenzidine (DAB) to construct HCC models were divided into control group, cancer-inducing group and UTI intervention group. In each group, rat liver samples were collected at weeks 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 respectively to study pathological distribution characteristics of oval cells in the process of carcinogenesis under optical microscope. Oval cells were separated by the methods of improved density gradient centrifugation and their structural characteristics were observed under optical microscope and electronic microscope respectively; the oval cells expressing C-kit and PCNA in the collected samples were observed by the methods of immunohistochemistry and image analysis and the expression of c-myc mRNA was also detected by reverse transcription polymerase chain reaction (RT-PCR).RESULTS: Oval cells proliferated firstly in the portal area then gradually migrated into hepatic parenchyma in the inducing group and intervention group. The oval cells distributed inside and outside the carcinoma nodes. The oval cells presented the characteristics of undifferentiated cells: a high ratio of nucleolus and cellular plasm and obvious nucleoli, rare organelle in plasm. Only a few mitochondria and endoplasmic reticulum and some villuslike apophysis on surface of cells could be seen. Cells stained with C-kit and PCNA antibody were mainly oval cells distributed in the portal area. The expression of cmyc mRNA increased with the progression of HCC.However, in the intervention group, UTI could retard its i n c rea se

  7. Short-term effects of ACTH on protein synthesis in adrenal cortex cells of young rats.

    Science.gov (United States)

    Magalhães, M C; Magalhães, M M; Cimbra, A

    1975-11-19

    Two units of ACTH were administered intraperitoneally to young 20 gm-rats which received an intravenous injection of L-leucine-3H thirteen min later. ACTH-injected rats, and control rats which received the isotope alone, were killed at 2-, 10-, 30- and 60-min intervals. Electron microscope autoradiographs in control animals showed strong amino-acid uptake at pulse time (2-min) in the cytoplasm of adrenal zona fasciculata cells. Label was shared between the endoplasmic reticulum (ER) and mitochondria, and a lower but still considerable uptake was seen in nucleoli. At first chase time interval (10-min) cytoplasmic labelling declined, while nuclear and nucleolar labelling increased, both changing little thereafter, and there was a 10-30 min Golgi peak. ACTH administration provoked an overall increase in amino-acid incorporation into cytoplasm, nucleus and nucleolus at pulse time, with no changes in the distribution of the reactions among organelles. Intensification of labelling was most evident over nucleoli, the grain density of which was four-times as high as in controls. The short-term increase in ER and mitochondrial protein synthesis observed after ACTH injections was considered to be consistent with the hypothesis that most newly-formed proteins in these cells may be involved in the regulation of steroidogenesis. The marked increase in nucleolar labelling suggested the presence of proteins involved in RNA synthesis.

  8. Biomimetic fat cell (BFC) modification and for lindane removal from aqueous solution.

    Science.gov (United States)

    Liyan, Song; Youcai, Zhao; Guojian, Wang; Bing, Li; Dongjie, Niu; Xiaoli, Chai

    2008-03-01

    To improve the regeneration ability of biomimetic fat cell (BFC), an innovative agent for hydrophobic organic contaminants (HOCs) removal, BFC was modified through introducing 1, 3, 5-benzenetricarboxyl trichloride with trifunctional group and heterocyclic piperazine in this research. Modified biomimetic fat cell (MBFC) has a good lindane removal capacity close to that of BFC and powder activated carbon (PAC), and the lindane removal is 97.68, 96.65 and 98.36% with 7 mg/L lindane initial concentration, respectively. At the same time, 20 mg/L MBFC or PAC is sufficient for 10 microg/L lindane removal, and in 20-60 mg/L doses range the lindane removal by both MBFC and PAC can reach 99.0%; When the doses is below 10 mg/L, MBFC showed better lindane removal than PAC and MBFC even could reach 96.8% lindane removal in 5 mg/L dose. Lindane removal by MBFC could be held on 95% above in first 6-time reuse. Though the lindane removal by MBFC decreased with the reuse time increasing, MBFC still could remove 80 % lindane after 9 times regeneration. In contract with BFC, MBFC showed obvious advantage on the regeneration. The lindane removal mechanism by MBFC, similar with BFC, includes bioaccumulation by MBFC nucleolus-triolein and adsorption by MBFC membrane, and the bioaccumulation is the main way.

  9. The Change of Microtubule Cytoskeleton in the Stem-Tip Cells of Sugarcane during Mitosis%甘蔗茎尖细胞有丝分裂过程中微管骨架的变化

    Institute of Scientific and Technical Information of China (English)

    李志刚; 赵洪波; 李素丽; 杨丽涛; 李杨瑞

    2008-01-01

    In order to understand the microtubule change of monoeotyls stem-tip during mitosis,the arrangement,transformation of microtubule array and its relation with chromosome movement during mitosis were studied with freezing microtome,indirect immunofluorescence,DAPI staining and fluorescence microscopy.The results showed that nueleolus was intact when the cortical miemtubules formed;cortical mierotubulos were changed into phramoplast microtubule bands at mitosis prophase.When phramoplast microtubule came into being,nuclear membrane was ruptured and chromosome was arranged at the position of cell plate;subsequently,phramoplast microtubules were changed into phragmoplast mierotubules,phramoplast mierotubules were shortening and microtubules on the sides of cell plate were increasing gradually,during this course sister chromatid was separated by microtubules at cell plate and tract to the two poles,forming phragmoplast microtubules.Then the nucleolus of two daughter cells formed and separated in the end with the increase of cells numbers.Therefore,cell division orientation could be judged from the arrangement of cell microtubules in different periods in order to understand its growth status.

  10. Phosphorylation of Def Regulates Nucleolar p53 Turnover and Cell Cycle Progression through Def Recruitment of Calpain3

    Science.gov (United States)

    Tao, Ting; Shi, Hui; Lo, Li Jan; Wang, Yingchun; Chen, Jun; Peng, Jinrong

    2016-01-01

    Digestive organ expansion factor (Def) is a nucleolar protein that plays dual functions: it serves as a component of the ribosomal small subunit processome for the biogenesis of ribosomes and also mediates p53 degradation through the cysteine proteinase calpain-3 (CAPN3). However, nothing is known about the exact relationship between Def and CAPN3 or the regulation of the Def function. In this report, we show that CAPN3 degrades p53 and its mutant proteins p53A138V, p53M237I, p53R248W, and p53R273P but not the p53R175H mutant protein. Importantly, we show that Def directly interacts with CAPN3 in the nucleoli and determines the nucleolar localisation of CAPN3, which is a prerequisite for the degradation of p53 in the nucleolus. Furthermore, we find that Def is modified by phosphorylation at five serine residues: S50, S58, S62, S87, and S92. We further show that simultaneous phosphorylations at S87 and S92 facilitate the nucleolar localisation of Capn3 that is not only essential for the degradation of p53 but is also important for regulating cell cycle progression. Hence, we propose that the Def-CAPN3 pathway serves as a nucleolar checkpoint for cell proliferation by selective inactivation of cell cycle-related substrates during organogenesis. PMID:27657329

  11. DGCR8 Localizes to the Nucleus as well as Cytoplasmic Structures in Mammalian Spermatogenic Cells and Epididymal Sperm

    Directory of Open Access Journals (Sweden)

    Akane Nakano

    2013-01-01

    Full Text Available The localization of DGCR8 in spermatogenic cells and sperm from rat and mouse was studied by immunofluorescence and immunoelectron microscopy. Spermatogenic cells from these species yielded similar DGCR8 localization pattern. Immunofluorescence microscopy results showed that DGCR8 localized to both the cytoplasm and nucleus. In the cytoplasm, diffuse cytosolic and discrete granular staining was observed. Dual staining showed that DGCR8 colocalized to the granules with MAEL (a nuage marker. In the nucleus of spermatocytes, both the nucleoli and nucleoplasm were stained, whereas in the nucleus of early spermatids small spots were stained. In late spermatids, DGCR8 localized to the tip of their head and to small granules (neck granules of the neck cytoplasm. The neck granules were also observed in the neck of epididymal sperm. Immunoelectron microscopy results showed that DGCR8 localized to nuage structures. Moreover, DGCR8 localized to nonnuage structures in late spermatids. DGCR8 also localized to the nucleolus and euchromatin in spermatocytes and round spermatids and to small granules in the nucleus of late spermatids. The results suggest that in spermatogenic cells DGCR8 localizes not only to the nuclei but also to the cytoplasmic structures such as nuage and nonnuage structures. Furthermore, DGCR8 seems to be imported into the egg with neck granules in sperm during fertilization.

  12. Suppression of tumor growth and angiogenesis by a specific antagonist of the cell-surface expressed nucleolin.

    Directory of Open Access Journals (Sweden)

    Damien Destouches

    Full Text Available BACKGROUND: Emerging evidences suggest that nucleolin expressed on the cell surface is implicated in growth of tumor cells and angiogenesis. Nucleolin is one of the major proteins of the nucleolus, but it is also expressed on the cell surface where is serves as a binding protein for variety of ligands implicated in cell proliferation, differentiation, adhesion, mitogenesis and angiogenesis. METHODOLOGY/PRINCIPAL FINDINGS: By using a specific antagonist that binds the C-terminal tail of nucleolin, the HB-19 pseudopeptide, here we show that the growth of tumor cells and angiogenesis are suppressed in various in vitro and in vivo experimental models. HB-19 inhibited colony formation in soft agar of tumor cell lines, impaired migration of endothelial cells and formation of capillary-like structures in collagen gel, and reduced blood vessel branching in the chick embryo chorioallantoic membrane. In athymic nude mice, HB-19 treatment markedly suppressed the progression of established human breast tumor cell xenografts in nude mice, and in some cases eliminated measurable tumors while displaying no toxicity to normal tissue. This potent antitumoral effect is attributed to the direct inhibitory action of HB-19 on both tumor and endothelial cells by blocking and down regulating surface nucleolin, but without any apparent effect on nucleolar nucleolin. CONCLUSION/SIGNIFICANCE: Our results illustrate the dual inhibitory action of HB-19 on the tumor development and the neovascularization process, thus validating the cell-surface expressed nucleolin as a strategic target for an effective cancer drug. Consequently, the HB-19 pseudopeptide provides a unique candidate to consider for innovative cancer therapy.

  13. An extracellular DNA mediated bystander effect produced from low dose irradiated endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Smirnova, Tatiana D.; Malinovskaya, Elena M.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2011-07-01

    The human umbilical vein endothelial cells culture was exposed to X-ray radiation in a low dose of 10 cGy. The fragments of extracellular genomic DNA (ecDNA{sup R}) were isolated from the culture medium after the short-term incubation. A culture medium of unirradiated endothelial cells was then supplemented with ecDNA{sup R}, followed by analysing the cells along the series of parameters (bystander effect). The exposed cells and bystander endotheliocytes showed similar response to low doses: approximation of the 1q12 loci of chromosome 1 and their transposition into the cellular nucleus, change in shape of the endotheliocytic nucleus, activation of the nucleolus organizing regions (NORs), actin polymerization, and an elevated level of DNA double-stranded breaks. Following blockade of TLR9 receptors with oligonucleotide-inhibitor or chloroquine in the bystander cells these effects - except of activation of NORs - on exposure to ecDNA{sup R} disappeared, with no bystander response thus observed. The presence of the radiation-induced apoptosis in the bystander effect being studied suggests a possibility for radiation-modified ecDNA fragments (i.e., stress signaling factors) to be released into the culture medium, whereas inhibition of TLR9 suggests the binding these ligands to the recipient cells. A similar DNA-signaling pathway in the bystander effect we previously described for human lymphocytes. Integrity of data makes it possible to suppose that a similar signaling mechanism which we demonstrated for lymphocytes (humoral system) might also be mediated in a monolayer culture of cells (cellular tissue) after the development of the bystander effect in them and transfer of stress signaling factors (ecDNA{sup R}) through the culture medium.

  14. Differences in nuclear DNA organization between lymphocytes, Hodgkin and Reed-Sternberg cells revealed by structured illumination microscopy.

    Science.gov (United States)

    Righolt, Christiaan H; Guffei, Amanda; Knecht, Hans; Young, Ian T; Stallinga, Sjoerd; van Vliet, Lucas J; Mai, Sabine

    2014-08-01

    Advances in light microscopy have enabled the visualization of DNA in the interphase nucleus with more detail than is visible with conventional light microscopy. The nuclear architecture is assumed to be different in cancer cells compared to normal cells. In this paper we have studied, for the first time, the organization of nuclear DNA and that of DNA-free space in control lymphocytes, Hodgkin cells and Reed-Sternberg cells using 3D structured illumination microscopy (SIM). We have observed detail in these SIM images that was not observed in conventional widefield images. We have measured the size distribution of the DNA structure using granulometry and noted a significant, progressive increase in the amount of sub-micron structures from control lymphocytes to Hodgkin cells to Reed-Sternberg cells. The DNA-free space changes as well; "holes" in the DNA distribution start to appear in the malignant cells. We have studied whether these "holes" are nucleoli by staining for upstream binding factor (UBF), a protein associated with the nucleolus. We have found that the relative UBF content progressively and significantly decreases-or is absent-in the DNA-free space when measured as either the Pearson correlation coefficient with the DNA-free space or as the number of "holes" that contain UBF. Similar differences exist within the population of Reed-Sternberg cells between binucleated and multinucleated cells with four or more subnuclei. To our knowledge, this is the first study that investigates the changes of the nuclear DNA structure in any disease with superresolution light microscopy.

  15. The photodamage effect and ROS generation induced by PDT with HMME in MCF-7cells in vitro

    Science.gov (United States)

    Yin, Huijuan; Li, Xiaoyuan; Liu, Jianzhong; Li, Yan

    2007-05-01

    Hematoporphyrin monomethyl ether (HMME) is a novel and promising porphyrin-related photosensitizer for photodynamic therapy (PDT). We use the human breast cancer MCF-7 cells to investigate the photodamage effect of HMME and reactive oxygen species (ROS) generation in HMME-PDT. Methods: The growth rates of MCF-7 cells at 24h after irradiation by 532nm laser with HMME of 5~20μg/ml and light dose of 0.3~4.8J/cm2 were determined by CCK-8 assays. Hoechst33342 staining was used to investigate the morphological change of the tumor cell. Flow cytometry combined with dual Annexin V/PI staining was used to identify the death mode of the cells following PDT. The changes of ROS labeled by DCFH-DA were observed by Laser Scanning Confocal Microscopy (LSCM). Our results show that HMME-based PDT induced significant cell death, and the photocytotoxity to MCF-7 cells is dose-dependent at the range of HMME concentration 5~20μg/ml and the light dose 0.3~4.8J/cm2. The nucleolus underwent apoptosis and/or necrosis observed by LSCM with Hoechst33342 staining. The necrosis and apoptosis rate were 16.0% and 12.4% respectively by FCM, showing the number of necrosic cells was more than that of apoptosis. There was an intense increase of fluorescence intensity standing for ROS generation within 30min post-PDT, and the peak was at about 10min after PDT. Our results suggest that HMME-PDT could inhibit the proliferation of MCF-7 cells remarkably. Because the MCF-7 cells lack procaspase-3, the apoptosis rate is lower. ROS played an important role in the photodamage with HMME.

  16. Ultrastructure of peripheral blood cells of highfin grouper Cromileptes altivelis%驼背鲈血细胞的超微结构

    Institute of Scientific and Technical Information of China (English)

    王静香; 李加儿; 区又君; 王永翠

    2011-01-01

    利用电镜技术对驼背鲈(Cromileptes altivelis)外周血细胞的超微结构进行了研究.结果表明,电镜下可区分6种类型的细胞:红细胞、粒细胞、单核细胞、淋巴细胞、血栓细胞和浆细胞.红细胞呈圆形或椭圆形,可见线粒体、少数囊泡;根据细胞中的颗粒形态大小和细胞核的形态,可将粒细胞分为4种类型:Ⅰ型粒细胞、Ⅱ型粒细胞、Ⅲ型粒细胞和Ⅳ型粒细胞.单核细胞圆形,表面较平整,偶有伪足伸出,空泡多见;淋巴细胞的胞质少,仅在细胞核边缘处形成薄薄的一层,细胞器少;血栓细胞异染色质丰富,沿核膜呈带状分布,胞质中有较多大小不等的空泡和少量的线粒体;浆细胞中粗面内质网成层分布包绕在核周围.此外可见到嗜曙红细胞吞噬红细胞、血栓细胞成群聚集分布的现象.%Using electron microscopy, we studied the ultrastructure of peripheral blood cells of Cromileptes allivelis. Six types of cells ( erythrocyte, granulocyte, monocyte, lymphocyte, thrombocyte and plasma cell) were detected under the electron microscope. Eryth rocyte is round or oval with visible mitochondria and a few vesicles. According to the size, shape of particles and form of nucleus, gran ulocytes can be divided into 4 types: Ⅰ-type granulocyte, Ⅱ-type granulocyte, Ⅲ-type granulocyte and Ⅳ-type granulocyte. Monocyte is round with smooth surface and vacuoles, occasionally holding out pseudopodia. Lymphocyte has a few organelles and little cytoplasm which only forms a thin layer around the nucleolus. Thrombocyte is rich in heterochromatins which distribute zonally along the nuclear membrane. There are many vacuoles at various sizes and a small amount of mitochondria. Rough endoplasmic reticulum distributes hi erarchically around the nucleolus in plasma cell. In addition, erythrocytes could be seen to be phagocytized by eosinophils and throm bocytes gathered in groups.

  17. Differentiation potentials of perivascular cells in the bone tissue remodeling zones under microgravity

    Science.gov (United States)

    Rodionova, Natalia; Katkova, Olena

    Adaptive remodeling processes in the skeleton bones occur in the close topographical interconnection with blood capillaries followed by perivascular cells. Radioautographic studies with 3Н- thymidine (Kimmel D.B., Fee W.S., 1980; Rodionova N.V., 1989, 2006) has shown that in osteogenesis zones there is sequential differentiation process of the perivascular cells into osteogenic ones. Using electron microscopy and cytochemistry we studied perivsacular cells in metaphysis of the rats femoral bones under conditions of modeling microgravity (28 days duration) and in femoral bonеs metaphyses of rats flown on board of the space laboratory (Spacelab - 2) It was revealed that population of the perivascular cells is not homogeneous in adaptive zones of the remodeling in both control and test groups (lowering support loading). This population comprises adjacent to endothelium little differentiated forms and isolated cells with differentiation features (specific volume of rough endoplasmic reticulum in cytoplasm is increased). Majority of the perivascular cells in the control group reveals reaction to alkaline phosphatase (marker of the osteogenic differentiation). In little differentiated cells this reaction is registered in nucleolus, nucleous and cytoplasm. In differentiating cells activity of the alkaline phosphatase is also detected on the outer surface of the cellular membrane. Unlike the control group in the bones of animals under microgravitaty reaction to the alkaline phosphatase is registered not for all cells of perivascular population. Part of the differentiating perivascular cells does not contain a product of the reaction. There is also visible trend of individual alkaline phosphatase containing perivascular cells amounts decrease (i.e. osteogenic cells-precursors). Under microgravity some little differentiated perivascular cells reveal destruction signs. Found decrease trend of the alkaline phosphatase containing cells (i.e. osteogenic cells) number in

  18. Changes in the population of perivascular cells in the bone tissue remodeling zones under microgravity

    Science.gov (United States)

    Katkova, Olena; Rodionova, Natalia; Shevel, Ivan

    2016-07-01

    Microgravity and long-term hypokinesia induce reduction both in bone mass and mineral saturation, which can lead to the development of osteoporosis and osteopenia. (Oganov, 2003). Reorganizations and adaptive remodeling processes in the skeleton bones occur in the topographical interconnection with blood capillaries and perivascular cells. Radioautographic studies with 3H- thymidine (Kimmel, Fee, 1980; Rodionova, 1989, 2006) have shown that in osteogenesis zones there is sequential differentiation process of the perivascular cells into osteogenic. Hence the study of populations of perivascular stromal cells in areas of destructive changes is actual. Perivascular cells from metaphysis of the rat femoral bones under conditions of modeling microgravity were studied using electron microscopy and cytochemistry (hindlimb unloading, 28 days duration) and biosatellite «Bion-M1» (duration of flight from April 19 till May 19, 2013 on C57, black mice). It was revealed that both control and test groups populations of the perivascular cells are not homogeneous in remodeling adaptive zones. These populations comprise of adjacent to endothelium poorly differentiated forms and isolated cells with signs of differentiation (specific increased volume of rough endoplasmic reticulum in cytoplasm). Majority of the perivascular cells in the control group (modeling microgravity) reveals reaction to alkaline phosphatase (marker of the osteogenic differentiation). In poorly differentiated cells this reaction is registered in nucleolus, nucleous and cytoplasm. In differentiating cells activity of the alkaline phosphatase is also detected on the outer surface of the cellular membrane. Unlike the control group in the bones of experimental animals reaction to the alkaline phosphatase is registered not in all cells of perivascular population. Part of the differentiating perivascular cells does not contain a product of the reaction. Under microgravity some poorly differentiated perivascular

  19. The transcriptional program of a human B cell line in response to Myc

    Science.gov (United States)

    Schuhmacher, Marino; Kohlhuber, Franz; Hölzel, Michael; Kaiser, Carmen; Burtscher, Helmut; Jarsch, Michael; Bornkamm, Georg W.; Laux, Gerhard; Polack, Axel; Weidle, Ulrich H.; Eick, Dirk

    2001-01-01

    The proto-oncogene c-myc (myc) encodes a transcription factor (Myc) that promotes growth, proliferation and apoptosis. Myc has been suggested to induce these effects by induction/repression of downstream genes. Here we report the identification of potential Myc target genes in a human B cell line that grows and proliferates depending on conditional myc expression. Oligonucleotide microarrays were applied to identify downstream genes of Myc at the level of cytoplasmic mRNA. In addition, we identified potential Myc target genes in nuclear run-on experiments by changes in their transcription rate. The identified genes belong to gene classes whose products are involved in amino acid/protein synthesis, lipid metabolism, protein turnover/folding, nucleotide/DNA synthesis, transport, nucleolus function/RNA binding, transcription and splicing, oxidative stress and signal transduction. The identified targets support our current view that myc acts as a master gene for growth control and increases transcription of a large variety of genes. PMID:11139609

  20. Depletion of SMN by RNA interference in HeLa cells induces defects in Cajal body formation.

    Science.gov (United States)

    Girard, Cyrille; Neel, Henry; Bertrand, Edouard; Bordonné, Rémy

    2006-01-01

    Neuronal degeneration in spinal muscular atrophy (SMA) is caused by reduced expression of the survival of motor neuron (SMN) protein. The SMN protein is ubiquitously expressed and is present both in the cytoplasm and in the nucleus where it localizes in Cajal bodies. The SMN complex plays an essential role for the biogenesis of spliceosomal U-snRNPs. In this article, we have used an RNA interference approach in order to analyse the effects of SMN depletion on snRNP assembly in HeLa cells. Although snRNP profiles are not perturbed in SMN-depleted cells, we found that SMN depletion gives rise to cytoplasmic accumulation of a GFP-SmB reporter protein. We also demonstrate that the SMN protein depletion induces defects in Cajal body formation with coilin being localized in multiple nuclear foci and in nucleolus instead of canonical Cajal bodies. Interestingly, the coilin containing foci do not contain snRNPs but appear to co-localize with U85 scaRNA. Because Cajal bodies represent the location in which snRNPs undergo 2'-O-methylation and pseudouridylation, our results raise the possibility that SMN depletion might give rise to a defect in the snRNA modification process.

  1. The sequential addition of ribosomal proteins during the formation of the small ribosomal subunit in Friend erythroleukemia cells.

    Science.gov (United States)

    Todorov, I T; Noll, F; Hadjiolov, A A

    1983-03-15

    Nucleolar '80-S' and '40-S' preribosomes (containing 45-S and 21-S pre-rRNA, respectively), as well as cytoplasmic ribosomes, were isolated from Friend erythroleukemia cells. The presence of structural ribosomal proteins in the isolated particles was studied by using antisera against individual rat liver small ribosomal subunit proteins. The analysis is based on the established crossreactivity between rat and mouse ribosomes [F. Noll and H. Bielka (1970) Mol. Gen. Genet. 106, 106-113]. The identification of the proteins was achieved by two independent immunological techniques: the passive haemagglutination test and the enzyme immunoassay of electrophoretically fractionated proteins, blotted on nitrocellulose. All 17 proteins tested are present in cytoplasmic ribosomes. A large number of proteins (S3a, S6, S7, S8, S11, S14, S18, S20, S23/24 and S25) are present in the '80-S' preribosome. Only two proteins (S3 and S21) are added during the formation of the '40-S' preribosome in the nucleolus. Four proteins (S2, S19, S26 and S29) are added at later, possibly extranucleolar, stages of ribosome formation. The results obtained provide evidence for the sequential addition of proteins during the formation of the small ribosomal subunit in Friend erythroleukemia cells.

  2. New cancer-treatment model of photodynamic therapy combined with a type I topoisomerase inhibitor, CPT-11, against HeLa cell tumors in nude mice used by OPO parametric tunable laser

    Science.gov (United States)

    Yoshida, Takato O.; Matsuzawa, Eiji; Matsuo, Tetsumichi; Koide, Yukio; Terakawa, Susumu; Yokokura, Teruo; Hirano, Toru

    1995-03-01

    A new cancer-treatment model, photodynamic therapy (PDT) combined with a type I topoisomerase inhibitor, camptothecin derivative (CPT-11), against HeLa cell tumors in BALB/c nude mice has been developed using a wide-band tunable coherent light source operated on optical parametric oscillation (OPO parametric tunable laser). The Photosan-3 PDT and CPT-11 combined therapy was remarkably effective, that is the inhibition rate (I.R.) 40 - 80%, as compared to PDT only in vivo. The analysis of HpD (Photosan-3) and CPT-11 effects on cultured HeLa cells in vitro has been studied by a video-enhanced contrast differential interference contrast microscope (VEC-DIC). Photosan-3 with 600 nm light killed cells by mitochondrial damage within 50 min, but not with 700 nm light. CPT-11 with 700 - 400 nm light killed cells within 50 min after nucleolus damage appeared after around 30 min. The localization of CPT-11 in cells was observed as fluorescence images in the nucleus, particularly the nucleoral area produced clear images using an Argus 100.

  3. Silencing of ribosomal protein S9 elicits a multitude of cellular responses inhibiting the growth of cancer cells subsequent to p53 activation.

    Directory of Open Access Journals (Sweden)

    Mikael S Lindström

    Full Text Available BACKGROUND: Disruption of the nucleolus often leads to activation of the p53 tumor suppressor pathway through inhibition of MDM2 that is mediated by a limited set of ribosomal proteins including RPL11 and RPL5. The effects of ribosomal protein loss in cultured mammalian cells have not been thoroughly investigated. Here we characterize the cellular stress response caused by depletion of ribosomal protein S9 (RPS9. METHODOLOGY/PRINCIPAL FINDINGS: Depletion of RPS9 impaired production of 18S ribosomal RNA and induced p53 activity. It promoted p53-dependent morphological differentiation of U343MGa Cl2:6 glioma cells as evidenced by intensified expression of glial fibrillary acidic protein and profound changes in cell shape. U2OS osteosarcoma cells displayed a limited senescence response with increased expression of DNA damage response markers, whereas HeLa cervical carcinoma cells underwent cell death by apoptosis. Knockdown of RPL11 impaired p53-dependent phenotypes in the different RPS9 depleted cell cultures. Importantly, knockdown of RPS9 or RPL11 also markedly inhibited cell proliferation through p53-independent mechanisms. RPL11 binding to MDM2 was retained despite decreased levels of RPL11 protein following nucleolar stress. In these settings, RPL11 was critical for maintaining p53 protein stability but was not strictly required for p53 protein synthesis. CONCLUSIONS: p53 plays an important role in the initial restriction of cell proliferation that occurs in response to decreased level of RPS9. Our results do not exclude the possibility that other nucleolar stress sensing molecules act upstream or in parallel to RPL11 to activate p53. Inhibiting the expression of certain ribosomal proteins, such as RPS9, could be one efficient way to reinitiate differentiation processes or to induce senescence or apoptosis in rapidly proliferating tumor cells.

  4. Bystin-like protein is upregulated in hepatocellular carci-noma and required for nucleologenesis in cancer cell pro-liferation

    Institute of Scientific and Technical Information of China (English)

    Hanzhi Wang; Wei Xiao; Qinbo Zhou; Yun Chen; Shuo Yang; Jiansong Sheng; Yanqing Yin; Jia Fan; Jia-wei Zhou

    2009-01-01

    The bystin-like (BYSL) gene was previously characterized to encode an accessory protein for cell adhesion that participates in early embryo implantation. It is also involved in 40S ribosomal subunit biogenesis and is found to be expressed in rapidly growing embryo and cancer cell lines. In order to explore the role of BYSL in cancer cell prolif-eration and growth, we used hepatocellular carcinoma (HCC) as a model. Here, we report that BYSL is crucial for HCC cell growth both in vitro and in vivo. Expression levels of BYSL mRNA and protein in human HCC specimens were markedly increased compared with those seen in adjacent non-cancerous tissue. In vitro, inhibition of BYSL by short hairpin RNA decreased HCC cell proliferation, induced apoptosis and partially arrested the cell cycle in the G2/M phase. In vivo, HCC cells treated with BYSL siRNA failed to form tumors in nude mice after subcutaneous im-plantation. To determine the cellular basis for BYSL RNAi-induced cell growth arrest, BYSL subcellular localization in mitotic and interphase HepG2 cells was examined. BYSL was present at multiple stages during nucleologenesis, including in nucleolus-derived foci (NDF), perichromosomal regions and the prenucleolar body (PNB) during mito-sis. BYSL depletion remarkably suppressed NDF and PNB formation, and disrupted nucleoli assembly after mitosis, resulting in increased apoptosis and reduced tolerance of HCC cells to serum starvation. Taken together, our studies indicate that upregulated BYSL expression plays a role in hepatocarcinogenesis.

  5. The invasion of tobacco mosaic virus RNA induces endoplasmic reticulum stress-related autophagy in HeLa cells.

    Science.gov (United States)

    Li, Li; Wang, Li; Xiao, Ruijing; Zhu, Guoguo; Li, Yan; Liu, Changxuan; Yang, Ru; Tang, Zhiqing; Li, Jie; Huang, Wei; Chen, Lang; Zheng, Xiaoling; He, Yuling; Tan, Jinquan

    2012-04-01

    The ability of human cells to defend against viruses originating from distant species has long been ignored. Owing to the pressure of natural evolution and human exploration, some of these viruses may be able to invade human beings. If their 'fresh' host had no defences, the viruses could cause a serious pandemic, as seen with HIV, SARS (severe acute respiratory syndrome) and avian influenza virus that originated from chimpanzees, the common palm civet and birds, respectively. It is unknown whether the human immune system could tolerate invasion with a plant virus. To model such an alien virus invasion, we chose TMV (tobacco mosaic virus) and used human epithelial carcinoma cells (HeLa cells) as its 'fresh' host. We established a reliable system for transfecting TMV-RNA into HeLa cells and found that TMV-RNA triggered autophagy in HeLa cells as shown by the appearance of autophagic vacuoles, the conversion of LC3-I (light chain protein 3-I) to LC3-II, the up-regulated expression of Beclin1 and the accumulation of TMV protein on autophagosomal membranes. We observed suspected TMV virions in HeLa cells by TEM (transmission electron microscopy). Furthermore, we found that TMV-RNA was translated into CP (coat protein) in the ER (endoplasmic reticulum) and that TMV-positive RNA translocated from the cytoplasm to the nucleolus. Finally, we detected greatly increased expression of GRP78 (78 kDa glucose-regulated protein), a typical marker of ERS (ER stress) and found that the formation of autophagosomes was closely related to the expanded ER membrane. Taken together, our data indicate that HeLa cells used ERS and ERS-related autophagy to defend against TMV-RNA.

  6. Transgenic mice for MTCP1 develop T-cell prolymphocytic leukemia.

    Science.gov (United States)

    Gritti, C; Dastot, H; Soulier, J; Janin, A; Daniel, M T; Madani, A; Grimber, G; Briand, P; Sigaux, F; Stern, M H

    1998-07-15

    T-cell prolymphocytic leukemia (T-PLL) is a rare form of mature T-cell leukemia associated with chromosomal rearrangements implicating MTCP1 or TCL1 genes. These genes encode two homologous proteins, p13(MTCP1) and p14(TCL1), which share no similarity with other known protein. To determine the oncogenic role of MTCP1, mice transgenic for MTCP1 under the control of CD2 regulatory regions (CD2-p13 mice) were generated. No abnormality was detected during the first year after birth. A late effect of the transgene was searched for in a cohort of 48 CD2-p13 mice aged 15 to 20 months, issued from 3 independent founders. Lymphoid hemopathies, occurring in the three transgenic lines, were characterized by lymphoid cells with an irregular nucleus, a unique and prominent nucleolus, condensed chromatin, a basophilic cytoplasm devoid of granules, and an immunophenotype of mature T cells. The molecular characterization of Tcrb rearrangements demonstrated the monoclonal origin of these populations. Histopathological analysis of the cohort demonstrated early splenic and hepatic infiltrations, whereas lymphocytosis and medullar infiltrations were found infrequently. The engraftment of these proliferations in H2-matched animals demonstrated their malignant nature. Cumulative incidence of the disease at 20 months was 100%, 50%, and 21% in F3, F4, and F7 lines, respectively, and null in the control group. The level of expression of the transgene, as estimated by Western blotting in the transgenic lines correlated with the tumoral incidence, with the highest expression of p13(MTCP1) being found in F3 mice. CD2-p13 transgenic mice developed an hemopathy similar to human T-PLL. These data demonstrate that p13(MTCP1) is an oncoprotein and that CD2-p13 transgenic mice represent the first animal model for mature T-PLL.

  7. Effects of High Temperature Stress on Microscopic and Ultrastructural Characteristics of Mesophyll Cells in Flag Leaves of Rice

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gui-lian; CHEN Li-yun; ZHANG Shun-tang; ZHENG Hua; LIU Guo-hua

    2009-01-01

    The microscopic and ultrastructural characteristics of mesophyll cells in flag leaves of two rice lines (a thermo- sensitive line 4628 and a thermo-resistant line 996) under high temperature stress (37°C during 8:00-17:00 and 30°C during 17:00-8:00) were investigated using an optical and a transmission electron microscopy. The membrane permeability and malondialdehyde content increased under the high temperature stress, and the increase of both variables was greater in the line 4628 than in the line 996. Under the high temperature stress, the line 996 showed tightly arranged mesophyll cells in flag leaves, fully developed vascular bundles and some closed stomata, whereas the line 4628 suffered from injury because of undeveloped vascular bundles, loosely arranged mesophyll cells and opened stomata. The mesophyll cells in flag leaves of the line 4628 were severely damaged under the high temperature stress, i.e. the chloroplast envelope became blurred, the grana thylakoid layer was arranged loosely and irregularly, the stroma layer disappeared, many osmiophilic granules appeared within the chloroplast, the outer membrane of mitochondria and the nucleus disintegrated and became blurred, the nucleolus disappeared, and much fibrillar-granular materials appeared within the nucleus. In contrast, the mesophyll cells in flag leaves of the line 996 maintained an intact ultrastructure under the high temperature stress. From these results, it is suggested that the ultrastructural modification of the cell membrane system is the primary plant response to high temperature stress and can be used as an index to evaluate the crop heat tolerance.

  8. The Cell Nucleus in Physiological and Experimentally Induced Hypometabolism

    Science.gov (United States)

    Malatesta, M.

    The main problem for manned space mission is, at present, represented by the mass penalty associated to the human presence. An efficient approach could be the induction of a hypometabolic stasis in the astronauts, thus drastically reducing the physical and psychological requirements of the crew. On the other hand, in the wild, a reduction in resource consumptions physiologi- cally occurs in certain animals which periodically enter hibernation, a hypometabolic state in which both the energy need and energy offer are kept at a minimum. During the last twelve years, we have been studying different tissues of hibernating dormice, with the aim of analyzing their features during the euthermia -hibernation-arousal cycle as well as getting insight into the mechanisms allowing adaptation to hypometabolism. We paid particular attention to the cell nucleus, as it is the site of chief metabolic functions, such as DNA replication and RNA transcription. Our observations revealed no significant modification in the basic features of cell nuclei during hibernation; however, the cell nuclei of hibernating dormice showed unusual nuclear bodies containing molecules involved in RNA pathways. Therefore, we supposed that they could represent storage/assembly sites of several factors for processing some RNA which could be slowly synthesised during hibernation and rapidly and abundantly released in early arousal in order to meet the increased metabolic needs of the cell. The nucleolus also underwent structural and molecular modifications during hibernation, maybe to continue important nucleolar functions, or, alternatively, permit a most efficient reactivation upon arousal. On the basis of the observations made in vivo , we recently tried to experimentally induce a reversible hypometabolic state in in vitro models, using cell lines derived from hibernating and non-hibernating species. By administering the synthetic opioid DADLE, we could significantly reduce both RNA transcrip- tion and

  9. Cell proliferation in Allium cepa L. meristems under 8-hydroxyquinoline, a chelating agent that affects DNA and RNA polymerases.

    Science.gov (United States)

    Ferrero, M L; De la Torre, C

    1986-02-01

    8-Hydroxyquinoline (HQ) chelates Mg2+ and Mn2+ and, secondarily, affects the activities of DNA and RNA polymerases. The in vivo effect of HQ has been estimated in Allium cepa L. meristems growing under new growth kinetics in the presence of this agent. HQ (at both 5 X 10(-5) M and 10(-4) M) depressed incorporation of [3H]uridine much more effectively than that of [3H]-thymidine. Cycle kinetics in meristems behaved as if they were independent of the rates of synthesis or accumulation of RNA since, under HQ, cycle time was only moderately modified and the new cycle kinetics achieved could be explained by the new rates of [3H]thymidine incorporation. Lengthened S periods were partially compensated for by shortened G2 phases, suggesting that, in these cells, both the growth cycle and its coupling with the DNA-division cycle were not disturbed by a decreased amount of RNA. Finally, the nucleolar cycle during mitosis, but not the interphase nucleolus, was modified under the new rates of RNA synthesis.

  10. Remodeling of ribosomal genes in somatic cells by Xenopus egg extract

    Energy Technology Data Exchange (ETDEWEB)

    Ostrup, Olga, E-mail: osvarcova@gmail.com [Institute of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C (Denmark); Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo (Norway); Norwegian Center for Stem Cell Research, Oslo (Norway); Hyttel, Poul; Klaerke, Dan A. [Institute of Basic Animal and Veterinary Sciences, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C (Denmark); Collas, Philippe, E-mail: philc@medisin.uio.no [Stem Cell Epigenetics Laboratory, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Oslo (Norway); Norwegian Center for Stem Cell Research, Oslo (Norway)

    2011-09-02

    Highlights: {yields} Xenopus egg extract remodels nuclei and alter cell growth characteristics. {yields} Ribosomal genes are reprogrammed within 6 h after extract exposure. {yields} rDNA reprogramming involves promoter targeting of SNF2H remodeling complex. {yields} Xenopus egg extract does not initiate stress-related response in somatic cells. {yields} Aza-cytidine elicits a stress-induced response in reprogrammed cells. -- Abstract: Extracts from Xenopus eggs can reprogram gene expression in somatic nuclei, however little is known about the earliest processes associated with the switch in the transcriptional program. We show here that an early reprogramming event is the remodeling of ribosomal chromatin and gene expression. This occurs within hours of extract treatment and is distinct from a stress response. Egg extract elicits remodeling of the nuclear envelope, chromatin and nucleolus. Nucleolar remodeling involves a rapid and stable decrease in ribosomal gene transcription, and promoter targeting of the nucleolar remodeling complex component SNF2H without affecting occupancy of the transcription factor UBF and the stress silencers SUV39H1 and SIRT1. During this process, nucleolar localization of UBF and SIRT1 is not altered. On contrary, azacytidine pre-treatment has an adverse effect on rDNA remodeling induced by extract and elicits a stress-type nuclear response. Thus, an early event of Xenopus egg extract-mediated nuclear reprogramming is the remodeling of ribosomal genes involving nucleolar remodeling complex. Condition-specific and rapid silencing of ribosomal genes may serve as a sensitive marker for evaluation of various reprogramming methods.

  11. Morphological study on permeating efficiency and localization of FCLA and HpD through membrane of lung cancer cell

    Science.gov (United States)

    Wu, Yunxia; Xing, Da; Tang, Yonghong

    2004-07-01

    It is reported that apoptosis of cancer cells in photodynamic therapy (PDT) is caused by 1O2 generated in photosensitization. In order to study the mechanism of this kind of 1O2-induced apoptosis, it is necessary to establish a special technique to dynamically detect intracellular production and localization of 1O2. FCLA, as a chemiluminescence probe to detect singlet oxygen (1O2) and superoxide (O2-.), has been used successfully in photodynamic and sonodynamic diagnosis in tissue level, recently. This paper reported a preliminary result of morphological study on permeating efficiency and localization of FCLA and hematoporphyrin derivative (HpD) through cellular membrane. Human lung cancer cell line (ASTC-a-1) was used in the experiment. The result of this research showed that both HpD and FCLA could permeate through cellular membrane and localize to prinuclear area, when HpD or FCLA was incubated with cells. Although the molecular weight of HpD is close to FCLA's, the permeating efficiency of HpD through membrane was different from that of FCLA. Intracellular FCLA concentration reached a peak after incubation for only 30 - 45 minutes, but amount of HpD in cells approached the equilibrium after incubation for near 22 h. In the experiment, we did not observe the evidence of FCLA or HpD penetrating into nucleolus. This study suggests that it is possibly to use a specific chemiluminescence probe to dynamcially detect the production and localization of 1O2 or 02-. in cell.

  12. Packaging of porcine reproductive and respiratory syndrome virus replicon RNA by a stable cell line expressing its nucleocapsid protein.

    Science.gov (United States)

    Song, Byung-Hak; Kim, Jeong-Min; Kim, Jin-Kyoung; Jang, Han-Saem; Yun, Gil-Nam; Choi, Eun-Jin; Song, Jae-Young; Yun, Sang-Im; Lee, Young-Min

    2011-06-01

    Porcine reproductive and respiratory syndrome virus (PRRSV), a member of the Arteriviridae family, is one of the most common and economically important swine pathogens. Although both live-attenuated and killed-inactivated vaccines against the virus have been available for a decade, PRRSV is still a major problem in the swine industry worldwide. To explore the possibility of producing single-round infectious PRRSV replicon particles as a potential vaccine strategy, we have now generated two necessary components: 1) a stable cell line (BHK/Sinrepl9/PRRSV-N) that constitutively expresses the viral nucleocapsid (N) protein localized to the cytoplasm and the nucleolus and 2) a PRRSV replicon vector (pBAC/PRRSV/Replicon-AN) with a 177-nucleotide deletion, removing the 3'-half portion of ORF7 in the viral genome, from which the self-replicating propagation-defective replicon RNAs were synthesized in vitro by SP6 polymerase run-off transcription. Transfection of this replicon RNA into N protein-expressing BHK-21 cells led to the secretion of infectious particles that packaged the replicon RNA, albeit with a low production efficiency of 0.4 × 10(2) to 1.1 × 10(2) infectious units/ml; the produced particles had only single-round infectivity with no cell-to-cell spread. This trans-complementation system for PRRSV provides a useful platform for studies to define the packaging signals and motifs present within the viral genome and N protein, respectively, and to develop viral replicon-based antiviral vaccines that will stop the infection and spread of this pathogen.

  13. 甜瓜花粉母细胞减数分裂及雄配子体的细胞学研究%Cytological Studies on Meiosis of Pollen Mother Cells and Development of Male Gametophyte in Melon

    Institute of Scientific and Technical Information of China (English)

    张永兵; 陈劲枫; 伊鸿平; 钱春桃; 吴明珠

    2011-01-01

    With improved staining and chromosome preparing method, thin and thick rind melon (Cucumis melo L. ) were used to study meiosis of pollen mother cells (PMC) and development of male gametophyte.The results indicated:(1)both types of melon have a simultaneous cytokinesis and a relative high synchronization in nuclear division. Nucleolus disappeared gradually from prophase Ⅰ to metaphase Ⅰ ,reappeared at prophase Ⅱ and then disappeared. With condensation of chromatins,chromosome became more and more identifiable from prophase Ⅰ to metaphase Ⅰ ,and illegible at telophase Ⅰ with de-helixation. Chromosomes were prominent again at both poles in PMC at prophase Ⅱ. (2)At diakinesis,most chromosome configurations were ring bivalents for all melons. (3)Two kinds division of chromosome were observed at anaphase Ⅱ , reciprocally vertical and parallel division. (4)Nucleolus number was more than other melons both at prophase Ⅰ and Ⅱ in Jiashi melon,which demonstrating the speciality of Jiashi melon. (5)During the development of male gametophyte, unicleate, bicleate and mature 3-celled pollen stage were observed in both types melon. It could be concluded that meiotic chromosome behaviors of PMC was accordant between two types melon in China,and the unique nucleolus number shown in Jiashi melon was relevant to ecological adaptability.%以薄皮和厚皮类型甜瓜为试材,采用改良的染色体制片方法,系统观察了甜瓜花粉母细胞的减数分裂及雄配子体发育的过程,结果表明:(1)甜瓜细胞核减数分裂的同步性较高,细胞质是同时型分裂,在细胞核分裂的过程中,核仁在前期Ⅰ到中期Ⅰ逐渐消失,在前期Ⅱ再次出现,随后消失,染色体在前期Ⅰ到中期Ⅰ逐渐收缩,变得清晰,至末期Ⅰ变得模糊,在前期Ⅱ再次清晰;(2)2种类型甜瓜终变期的染色体构型都以环状二价体为主;(3)在后期Ⅱ,观察到染色体的垂直和平行2种分离方式;(4)在前期Ⅰ和前期

  14. Effects of ACTH on RNA synthesis and migration in the adrenal cortex cells of the young rat, as shown by radioautography

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, M.C.; Vitor, A.B.; Magalhaes, M.M.

    1986-01-01

    The effect of ACTH on the RNA synthesis in adrenal zona fasciculata cells of the young rat were studied by light and electron microscope radioautography. Two units of ACTH were administered sc to animals and immediately followed by an iv injection of (/sup 3/)uridine. ACTH-injected and control rats, which received the isotope alone, were sacrificed at various time intervals. Labelling over extranucleolar areas was higher in the ACTH-treated animals at 20 min, then becoming lower than in the controls at 60 min and 24 h. Nucleolar radioactivity, however, was consistently decreased by ACTH at all experimental times. Apart from these changes in the rate of synthesis, the over-all curves of labelling were similar to those in the control animals with a striking peak at 1 h. The short-term increase in extranucleolar RNA synthesis observed after ACTH injection was considered to be consistent with the hypothesis that an enhanced extranucleolar synthesis of mRNA takes place early in stimulated animals and is associated with the synthesis of steroidogenic proteins. On the other hand, the relatively decreased uridine uptake of the label by the nucleolus in ACTH-treated animals, suggests an inhibition of nucleolar transcription with diminished pre-rRNA formation in treated animals.

  15. Stem Cells

    Science.gov (United States)

    Stem cells are cells with the potential to develop into many different types of cells in the body. ... the body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  16. 南瓜花粉母细胞减数分裂及雄配子体发育研究%Pollen Mother Cell Miosis and Male Gametophvte Development of Pumpkin

    Institute of Scientific and Technical Information of China (English)

    崔群香; 刘卫东; 王倩; 肖木珠

    2012-01-01

    [Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich's hematoxylin staining-methyl salicylate clearing technique was used for observation and research of the variation of cell structure and chromosomal behavior during pollen mother cell miosis and male gametophyte development of ' Tianhong' pumpkin. [ Result ] We found that the meiosis in pollen mother cells of pumpkin was simultaneous cytokinesis. In the process of nuclear division, nuclear membrane and nucleolus of pumpkin pollen mother cells gradually disappeared in the metaphase I and reappeared in telophase I , phragmoplast formed between the two generated crescent-shaped nuclei without cell wall, the phragmoplast gradually disappeared in the metaphase II and reappeared in telophase II . Phragmoplast spread outward from the center of spindle during the second division was connected with that formed on the central interface of two nuclei during the first division, cell wall of microspores generated from periphery to center. Most of the tetrads contained four sub-cells while a few contained extra small cells. During the period of uniuclete microspore at periphery, the single nucleolus split into 2 - 3 or more small nucleoli, mature pollen grain was two-celled. Mononucleate pollen cells were mostly appeared in the flower buds with length of 1.0 -2.0 cm, which could be used as an important indicator to collect materials for anther or microspore culture. [Conclusion] This study had laid the foundation for research of the cytogenetics of pumpkin.%[目的]研究南瓜花粉母细胞的减数分裂及其雄配子体发育过程,以期为南瓜花药培养等方面研究提供一定细胞学依据.[方法]采用爱氏苏木精染色-冬青油透明技术对南瓜“天虹”的花粉母细胞减数分裂及其雄配子体发育过程中细胞结构变化和染色体行

  17. Epigenetic Changes are Associated with Programmed Cell Death Induced by Heat Stress in Seedling Leaves of Zea mays.

    Science.gov (United States)

    Wang, Pu; Zhao, Lin; Hou, Haoli; Zhang, Hao; Huang, Yan; Wang, Yapei; Li, Hui; Gao, Fei; Yan, Shihan; Li, Lijia

    2015-05-01

    Histone modification plays a crucial role in regulation of chromatin architecture and function, responding to adverse external stimuli. However, little is known about a possible relationship between epigenetic modification and programmed cell death (PCD) in response to environmental stress. Here, we found that heat stress induced PCD in maize seedling leaves which was characterized by chromatin DNA laddering and DNA strand breaks detected by a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) test. The activities of the reactive oxygen species (ROS)-related enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) were progressively increased over time in the heat-treated seedlings. However, the concentration of H2O2 remained at relatively lower levels, while the concentration of superoxide anion ([Formula: see text]) was increased, accompanied by the occurrence of higher ion leakage rates after heat treatment. The total acetylation levels of histones H3K9, H4K5 and H3 were significantly increased, whereas the di-methylation level of histone H3K4 was unchanged and the di-methylation level of histone H3K9 was decreased in the seedling leaves exposed to heat stress compared with the control seedlings, accompanied by increased nucleolus size indicative of chromatin decondensation. Furthermore, treatment of seedlings with trichostatin A (TSA), which always results in genomic histone hyperacetylation, caused an increase in the [Formula: see text] level within the cells. The results suggested that heat stress persistently induced [Formula: see text], leading to PCD in association with histone modification changes in the maize leaves.

  18. An efficient algorithm for nucleolus and prekernel computation in some classes of TU-games

    NARCIS (Netherlands)

    Faigle, U.; Kern, W.; Kuipers, J.

    1998-01-01

    We consider classes of TU-games. We show that we can efficiently compute an allocation in the intersection of the prekernel and the least core of the game if we can efficiently compute the minimum excess for any given allocation. In the case where the prekernel of the game contains exactly one core

  19. HIV-1 nucleocapsid protein localizes efficiently to the nucleus and nucleolus.

    Science.gov (United States)

    Yu, Kyung Lee; Lee, Sun Hee; Lee, Eun Soo; You, Ji Chang

    2016-05-01

    The HIV-1 nucleocapsid (NC) is an essential viral protein containing two highly conserved retroviral-type zinc finger (ZF) motifs, which functions in multiple stages of the HIV-1 life cycle. Although a number of functions for NC either in its mature form or as a domain of Gag have been revealed, little is known about the intracellular localization of NC and, moreover, its role in Gag protein trafficking. Here, we have investigated various forms of HIV-1 NC protein for its cellular localization and found that the NC has a strong nuclear and nucleolar localization activity. The linker region, composed of a stretch of basic amino acids between the two ZF motifs, was necessary and sufficient for the activity.

  20. 创伤与核转录因子%Trauma and nucleolus transcription factors

    Institute of Scientific and Technical Information of China (English)

    国华; 梁华平; 罗艳

    2002-01-01

    许多转录因子与创伤密切相关,除了研究较多的核因子κB(NF-κB),还有早期生长反应因子(EGR-1)、活化T细胞核因子(NFAT)、特殊蛋白1(SP-1)等核转录因子参与创伤反应,在创伤后的炎症、免疫反应和修复中起着重要作用.

  1. A cooperative game of information trading: The core, the nucleolus and the kernel

    NARCIS (Netherlands)

    Driessen, T.; Muto, S.; Nakayama, M.

    1992-01-01

    A certain trade of the information about a technological innovation between the initial owner of the information andn identical producers is studied by means of a cooperative game theoretic approach. The information trading situation is modelled as a cooperative (n+1)-person game with side payments.

  2. Standard karyotype and nucleolus organizer region of Neotropical blindsnake Typhlops brongersmianus (Serpentes: Typhlopidae

    Directory of Open Access Journals (Sweden)

    José Augusto Ruiz García

    2007-11-01

    Full Text Available The karyotype of Typhlops brongersmianus is reported on the basis of specimens from north-eastern Argentina. The conventional Giemsa staining showed that the species has 2n = 34 chromosomes, including 8 pairs of macrochromosomes and 9 pairs of microchromosomes. Ag-NOR staining revealed the NORs location on a pair of macrochromosomes. The chromosome number and karyotypic morphology are similar to those of Neotropical typhlopid previously karyotyped.

  3. The Nucleolus as a Consistent Power Index in Noncooerative Majority Games

    NARCIS (Netherlands)

    Montero, M.P.

    2001-01-01

    This paper studies noncooperative bargaining with random proposers in proper single games. A power index is called consistent if it can be obtained as an equilibrium of the game with random proposers using the index itself as probability vector. Unlike the Shapley-Shubik and Banzhaf indices, the nuc

  4. Molecular cloning of a novel human I-mfa domain-containing protein that differently regulates human T-cell leukemia virus type I and HIV-1 expression.

    Science.gov (United States)

    Thébault, S; Gachon, F; Lemasson, I; Devaux, C; Mesnard, J M

    2000-02-18

    Regulation of viral genome expression is the result of complex cooperation between viral proteins and host cell factors. We report here the characterization of a novel cellular factor sharing homology with the specific cysteine-rich C-terminal domain of the basic helix-loop-helix repressor protein I-mfa. The synthesis of this new factor, called HIC for Human I-mfa domain-Containing protein, is controlled at the translational level by two different codons, an ATG and an upstream non-ATG translational initiator, allowing the production of two protein isoforms, p32 and p40, respectively. We show that the HIC protein isoforms present different subcellular localizations, p32 being mainly distributed throughout the cytoplasm, whereas p40 is targeted to the nucleolus. Moreover, in trying to understand the function of HIC, we have found that both isoforms stimulate in T-cells the expression of a luciferase reporter gene driven by the human T-cell leukemia virus type I-long terminal repeat in the presence of the viral transactivator Tax. We demonstrate by mutagenesis that the I-mfa-like domain of HIC is involved in this regulation. Finally, we also show that HIC is able to down-regulate the luciferase expression from the human immunodeficiency virus type 1-long terminal repeat induced by the viral transactivator Tat. From these results, we propose that HIC and I-mfa represent two members of a new family of proteins regulating gene expression and characterized by a particular cysteine-rich C-terminal domain.

  5. Penetration of short fluorescence-labeled peptides into the nucleus in HeLa cells and in vitro specific interaction of the peptides with deoxyribooligonucleotides and DNA.

    Science.gov (United States)

    Fedoreyeva, L I; Kireev, I I; Khavinson, V Kh; Vanyushin, B F

    2011-11-01

    Marked fluorescence in cytoplasm, nucleus, and nucleolus was observed in HeLa cells after incubation with each of several fluorescein isothiocyanate-labeled peptides (epithalon, Ala-Glu-Asp-Gly; pinealon, Glu-Asp-Arg; testagen, Lys-Glu-Asp-Gly). This means that short biologically active peptides are able to penetrate into an animal cell and its nucleus and, in principle they may interact with various components of cytoplasm and nucleus including DNA and RNA. It was established that various initial (intact) peptides differently affect the fluorescence of the 5,6-carboxyfluorescein-labeled deoxyribooligonucleotides and DNA-ethidium bromide complexes. The Stern-Volmer constants characterizing the degree of fluorescence quenching of various single- and double-stranded fluorescence-labeled deoxyribooligonucleotides with short peptides used were different depending on the peptide primary structures. This indicates the specific interaction between short biologically active peptides and nucleic acid structures. On binding to them, the peptides discriminate between different nucleotide sequences and recognize even their cytosine methylation status. Judging from corresponding constants of the fluorescence quenching, the epithalon, pinealon, and bronchogen (Ala-Glu-Asp-Leu) bind preferentially with deoxyribooligonucleotides containing CNG sequence (CNG sites are targets for cytosine DNA methylation in eukaryotes). Epithalon, testagen, and pinealon seem to preferentially bind with CAG- but bronchogen with CTG-containing sequences. The site-specific interactions of peptides with DNA can control epigenetically the cell genetic functions, and they seem to play an important role in regulation of gene activity even at the earliest stages of life origin and in evolution.

  6. A Case of Multiple Extranodal NK/T-cell Lymphoma,Nasal Type%多发性结外鼻型NK/T细胞淋巴瘤1例

    Institute of Scientific and Technical Information of China (English)

    孟慧敏; 王琳; 刘宏杰; 郭在培

    2011-01-01

    患者男,60岁,藏族.全身斑块、结节及肿块6月,肿块破渍伴疼痛2月.皮损病理组织示:表皮变薄,基底层液化变性,瘤细胞在真皮及皮下脂肪层呈弥漫性浸润,瘤细胞形态不一,核深染,可见血管中心性浸润及凝固性坏死.免疫组化标记瘤细胞CD3,CD3e,CD56,TIA-1,粒酶B均为(+),CD30约10%(+).CD8(-),CD79a(-),EBER1/2原位杂交(+).TCR-γ重排未见明确克隆性重排条带.诊断:皮肤结外鼻型NK/T细胞淋巴瘤.%A 60-year-old Tibetan nationality male patient presented with an over six month's history of plaque, nodules and lumps all over his body. Two months ago, the lumps developed to ulceration and accompanied pain. The pathologic features consist of thinning epidermis, liquefaction degeneration of basal cell, diffuse infiltrations of tumor cells in dermis and subcutaneous lipid tissue, which with various shapes and nucleolus hyperchromatism, blood vessels with centricity infiltrations, coagulation necrosis. The immunohistochemitry mark showed the tumor cells were positive with CD3, CD3ε, CD56, TIA-1, GrB and 1/2EBER in situ hybridization, about 10% tumor cells positive with CD30,but negative with CD8 and CD79a, TCR-rearrangement were not identify clone rearrange stripes. Extranodal nasal-type NK/T-cell lymphoma was diagnosed.

  7. Dendritic Cell

    OpenAIRE

    Sevda Söker

    2005-01-01

    Dendritic cells, a member of family of antigen presenting cells, are most effective cells in the primary immune response. Dendritic cells originated from dendron, in mean of tree in the Greek, because of their long and elaborate cytoplasmic branching processes. Dendritic cells constitute approximately 0.1 to 1 percent of the blood’s mononuclear cell. Dendritic cells are widely distributed, and specialized for antigen capture and T cell stimulation. In this article, structures and functions of...

  8. 吗啡对人胃癌MGC-803细胞p53 mRNA和E2F-1 mRNA表达的影响%Effect of morphine on expression of p53 mRNA and E2F-1 mRNA in human gastric carcinoma cell line MGC-803

    Institute of Scientific and Technical Information of China (English)

    覃怡; 唐小曼; 廖淳杰; 谢玉波

    2010-01-01

    Objective To investigate the effect of morphine on the expression of p53 mRNA and E2F-1 mRNA in human gastric carcinoma cell line MGC-803 .Methods The human gastric cancer cell line MGC-803 was purchased from Cell Biology Research Institute, Chinese Academy of Sciences, and cultured in DMEM liquid culture mediun. The cells were seeded in 6-well plates (1 × 103/ml or 2 × 105/ml, 1 ml/well) and divided into 2 groups (n = 18 wells each):group Ⅰ normal control (group C); group Ⅱ was exposed to 10 μmol/L morphine (group M). The proliferation of the cells was determined by colony formation assay at 7 day of incubation with morphine. The expression of p53 mRNA and E2F-1 mRNA was detected and the ulrastructure of the cells examined with transmission electron microscope after being incubated with morphine for 24 h. Results The proliferation of the cells and E2F-1 mRNA expression were significantly lower and p53 mRNA expression was significantly higher in group M than in group C (P < 0.05). The nuclear evelope was intact and the nucleolus and chromosomes were clearly visible in group C, while in group M fragmentation of nuclear envelope and nucleolus and apoptotic bodies were observed. Conclusion Morphine can inhibit the proliferation of the cells and accelerate the cell apoptosis through up-regulating the expression of p53 gene and down-regulating the expression of E2F-1gene in human gastric carcinoma cell line MGC-803.%目的 探讨吗啡对人胃癌MGC-803细胞p53 mRNA和E2F-1 mRNA表达的影响.方法 人胃癌MGC-803细胞以1×103/ml或2×105/ml密度接种于6孔培养板中,1 ml/孔,随机分为2组(n=18),正常对照组(C组)不作任何处理,吗啡组(M组)加入吗啡,使其终浓度为10μmol/L.于吗啡孵育7 d时应用克隆形成实验测定细胞增殖情况,于吗啡孵育24 h时测定细胞中p53 mRNA、E2F-1 mRNA的表达情况,并采用透射电子显微镜观察细胞超微结构.结果 与C组比较,M组克隆形成率降低,p53 m

  9. Mechanical continuity and reversible chromosome disassembly within intact genomes removed from living cells

    Science.gov (United States)

    Maniotis, A. J.; Bojanowski, K.; Ingber, D. E.

    1997-01-01

    Chromatin is thought to be structurally discontinuous because it is packaged into morphologically distinct chromosomes that appear physically isolated from one another in metaphase preparations used for cytogenetic studies. However, analysis of chromosome positioning and movement suggest that different chromosomes often behave as if they were physically connected in interphase as well as mitosis. To address this paradox directly, we used a microsurgical technique to physically remove nucleoplasm or chromosomes from living cells under isotonic conditions. Using this approach, we found that pulling a single nucleolus or chromosome out from interphase or mitotic cells resulted in sequential removal of the remaining nucleoli and chromosomes, interconnected by a continuous elastic thread. Enzymatic treatments of interphase nucleoplasm and chromosome chains held under tension revealed that mechanical continuity within the chromatin was mediated by elements sensitive to DNase or micrococcal nuclease, but not RNases, formamide at high temperature, or proteases. In contrast, mechanical coupling between mitotic chromosomes and the surrounding cytoplasm appeared to be mediated by gelsolin-sensitive microfilaments. Furthermore, when ion concentrations were raised and lowered, both the chromosomes and the interconnecting strands underwent multiple rounds of decondensation and recondensation. As a result of these dynamic structural alterations, the mitotic chains also became sensitive to disruption by restriction enzymes. Ion-induced chromosome decondensation could be blocked by treatment with DNA binding dyes, agents that reduce protein disulfide linkages within nuclear matrix, or an antibody directed against histones. Fully decondensed chromatin strands also could be induced to recondense into chromosomes with pre-existing size, shape, number, and position by adding anti-histone antibodies. Conversely, removal of histones by proteolysis or heparin treatment produced chromosome

  10. Galvanic Cells

    Science.gov (United States)

    Young, I. G.

    1973-01-01

    Many standard physical chemistry textbooks contain ambiguities which lead to confusion about standard electrode potentials, calculating cell voltages, and writing reactions for galvanic cells. This article shows how standard electrode potentials can be used to calculate cell voltages and deduce cell reactions. (Author/RH)

  11. Cell Biochips

    Science.gov (United States)

    Pioufle, B. Le; Picollet-D'Hahan, N.

    A cell biochip is a microsystem, equipped with electronic and microfluidic functions, designed to manipulate or analyse living cells. The first publications in this emerging area of research appeared toward the end of the 1980s. In 1989 Washizu described a biochip designed to fuse two cells by electropermeabilisation of the cytoplasmic membrane [1]. Research centers have devised a whole range of cell chip structures, for simultaneous or sequential analysis of single cells, cell groups, or cell tissues reconstituted on the chip. The cells are arranged in a square array on a parallel cell chip for parallel analysis, while they are examined and processed one by one in a microchannel in the case of a series cell chip. In contrast to these biochips for high-throughput analysis of a large number of cells, single-cell chips focus on the analysis of a single isolated cell. As in DNA microarrays, where a large number of oligonucleotides are ordered in a matrix array, parallel cell chips order living cells in a similar way. At each point of the array, the cells can be isolated, provided that the cell type allows this, e.g., blood cells, or cultivated in groups (most adhesion cells can only survive in groups). The aim is to allow massively parallel analysis or processing. Le Pioufle et al. describe a microdevice for the culture of single cells or small groups of cells in a micropit array [2]. Each pit is equipped to stimulate the cell or group of cells either electrically or fluidically. Among the applications envisaged are gene transfer, cell sorting, and screening in pharmacology. A complementary approach, combining the DNA microarray and cell biochip ideas, has been put forward by Bailey et al. [3]. Genes previously arrayed on the chip transfect the cultured cells on the substrate depending on their position in the array (see Fig. 19.1). This way of achieving differential lipofection on a chip was then taken up again by Yoshikawa et al. [4] with primary cells, more

  12. EXPRESSION AND SUBCELLULAR LOCALIZATION OF DNA-PK IN NASOPHARYNGEAL CARCINOMA CELL LINES CNE1 AND CNE2 WITH DIFFERENT RADIOSENSITIVITY

    Institute of Scientific and Technical Information of China (English)

    ZHONG Ping-ping; HE Yu-xiang; XIA Yun-fei; YAN Shan-shan

    2006-01-01

    Objective: Radiosensitivity is mainly determined by the number of DNA double-strand breaks (DSBs) induced by ionizing radiation and the extent of its repair. The DNA-PK complex formation is one of the major pathways by which the mammalian cells respond to DSBs repairing. Our previous study suggested that CNE1 is more radioresistant than CNE2. This study was designed to answer whether the radiosensitive difference of Nasopharyngeal Carcinoma cell lines CNE 1/CNE2 was related to the expression and localization of Ku70/Ku80/DNA-PKcs. Methods: Immunohistochemistry was performed to detect the subcellular localization of Ku70/Ku80/DNA-PKcs in NPC cells lines CNE1 and CNE2. Western-blot was used to determine the expression of Ku protein in total extract of CNE1 and CNE2 and semi-quantitative assay of protein expression was performed to estimate the optic density (OD) value of each band using automatic image analysis system. Results:Ku70/Ku80/DNA-PKcs primarily located in the nuclei. A part of nucleolus in CNE1 and CNE2 showed positive dyeing of DNA-PKcs. Protein expression of Ku70/Ku80/DNA-PKcs was detected in CNE1 and CNE2, and the integral optical density (IOD) of Ku70 protein was 22.03 ± 7.56 and 19.98 ± 6.04 respectively (t=0.021, P>0.05), while the IODs of Ku80 protein in the two cell lines were 33.44 ± 12.87 and 28.98 ± 9.24 respectively (t=0.24, P>0.05), and the IODs of DNA-PKcs protein were 45.03 ± 1.77 and 40.87 ± 4.19 (t=1.58, P>0.05). The above results suggested that the basic expression of Ku70/Ku80/DNA-PKcs had no statistic difference between the different radiosensitive NPC cell lines CNE1 and CNE2.Conclusion: The variation of radiosensitivity in NPC cell lines CNE1 and CNE2 has no obviously correlation with the subcellular localization and basic expression of DNA-PK protein. So we presumed that the difference of radiosensitivity between CNE1 and CNE2 may be on account of some other factors than subcellular localization and basic expression of

  13. Extracellular signal-regulated kinase 2 (ERK-2) mediated phosphorylation regulates nucleo-cytoplasmic shuttling and cell growth control of Ras-associated tumor suppressor protein, RASSF2

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Gita [Laboratory of Molecular Virology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500076 (India); Mahalingam, S., E-mail: mahalingam@iitm.ac.in [Laboratory of Molecular Virology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad 500076 (India); Department of Biotechnology, Laboratory of Molecular Virology and Cell Biology, Indian Institute of Technology-Madras, Chennai 600 036 (India)

    2009-10-01

    Ras GTPase controls the normal cell growth through binding with an array of effector molecules, such as Raf and PI3-kinase in a GTP-dependent manner. RASSF2, a member of the Ras association domain family, is known to be involved in the suppression of cell growth and is frequently down-regulated in various tumor tissues by promoter hypermethylation. In the present study, we demonstrate that RASSF2 shuttles between nucleus and cytoplasm by a signal-mediated process and its export from the nucleus is sensitive to leptomycin B. Amino acids between 240 to 260 in the C-terminus of RASSF2 harbor a functional nuclear export signal (NES), which is necessary and sufficient for efficient export of RASSF2 from the nucleus. Substitution of conserved Ile254, Val257 and Leu259 within the minimal NES impaired RASSF2 export from the nucleus. In addition, wild type but not the nuclear export defective RASSF2 mutant interacts with export receptor, CRM-1 and exported from the nucleus. Surprisingly, we observed nucleolar localization for the nuclear export defective mutant suggesting the possibility that RASSF2 may localize in different cellular compartments transiently in a cell cycle dependent manner and the observed nuclear localization for wild type protein may be due to faster export kinetics from the nucleolus. Furthermore, our data suggest that RASSF2 is specifically phosphorylated by MAPK/ERK-2 and the inhibitors of MAPK pathway impair the phosphorylation and subsequently block the export of RASSF2 from the nucleus. These data clearly suggest that ERK-2 mediated phosphorylation plays an important role in regulating the nucleo-cytoplasmic shuttling of RASSF2. Interestingly, nuclear import defective mutant of RASSF2 failed to induce cell cycle arrest at G1/S phase and apoptosis suggesting that RASSF2 regulates cell growth in a nuclear localization dependent manner. Collectively, these data provided evidence for the first time that MAPK/ERK-2 mediated phosphorylation regulates

  14. Multifunctional Pt(II) Reagents: Covalent Modifications of Pt Complexes Enable Diverse Structural Variation and In-Cell Detection.

    Science.gov (United States)

    White, Jonathan D; Haley, Michael M; DeRose, Victoria J

    2016-01-19

    Pt(II)-neutral complex analogous in structure to the aforementioned difunctional azide-Pt(II) reagent. In all cases, significant accumulation of Pt in the nucleolus of cells was observed, in addition to broader localization in the nucleus and cytoplasm of the cell. Using the same strategy of postbinding click modification with fluorescent probes, Pt adducts were detected and roughly quantified on rRNA and tRNA from Pt-treated Saccharomyces cerevisiae; rRNA adducts were found to be relatively long-lived and not targeted for immediate degradation. Finally, the utility and feasibility of the alkyne-appended Pt(II) compound has been further demonstrated with a turn-on fluorophore, dansyl azide, in fluorescent detection of DNA in vitro. In all, these modifications utilizing reactive handles have allowed for the diversification of new Pt reagents, as well as providing cellular localization information on the modified Pt compounds.

  15. 1A6/DRIM, a novel t-UTP, activates RNA polymerase I transcription and promotes cell proliferation.

    Directory of Open Access Journals (Sweden)

    Qunhui Peng

    Full Text Available BACKGROUND: Ribosome biogenesis is required for protein synthesis and cell proliferation. Ribosome subunits are assembled in the nucleolus following transcription of a 47S ribosome RNA precursor by RNA polymerase I and rRNA processing to produce mature 18S, 28S and 5.8S rRNAs. The 18S rRNA is incorporated into the ribosomal small subunit, whereas the 28S and 5.8S rRNAs are incorporated into the ribosomal large subunit. Pol I transcription and rRNA processing are coordinated processes and this coordination has been demonstrated to be mediated by a subset of U3 proteins known as t-UTPs. Up to date, five t-UTPs have been identified in humans but the mechanism(s that function in the t-UTP(s activation of Pol I remain unknown. In this study we have identified 1A6/DRIM, which was identified as UTP20 in our previous study, as a t-UTP. In the present study, we investigated the function and mechanism of 1A6/DRIM in Pol I transcription. METHODOLOGY/PRINCIPAL FINDINGS: Knockdown of 1A6/DRIM by siRNA resulted in a decreased 47S pre-rRNA level as determined by Northern blotting. Ectopic expression of 1A6/DRIM activated and knockdown of 1A6/DRIM inhibited the human rDNA promoter as evaluated with luciferase reporter. Chromatin immunoprecipitation (ChIP experiments showed that 1A6/DRIM bound UBF and the rDNA promoter. Re-ChIP assay showed that 1A6/DRIM interacts with UBF at the rDNA promoter. Immunoprecipitation confirmed the interaction between 1A6/DRIM and the nucleolar acetyl-transferase hALP. It is of note that knockdown of 1A6/DRIM dramatically inhibited UBF acetylation. A finding of significance was that 1A6/DRIM depletion, as a kind of nucleolar stress, caused an increase in p53 level and inhibited cell proliferation by arresting cells at G1. CONCLUSIONS: We identify 1A6/DRIM as a novel t-UTP. Our results suggest that 1A6/DRIM activates Pol I transcription most likely by associating with both hALP and UBF and thereby affecting the acetylation of UBF.

  16. Association of topoisomerase II with the hepatoma cell nuclear matrix: the role of intermolecular disulfide bond formation.

    Science.gov (United States)

    Kaufmann, S H; Shaper, J H

    1991-02-01

    Previous studies have resulted in conflicting data regarding the recovery of the nuclear enzymes topoisomerase (topo) II and topo I in the nuclear matrix fraction. In the present study we have assessed the effect of systematically altering a single extraction procedure on the distribution of these enzymes during the subfractionation of nuclei from HTC hepatoma tissue culture cells. When nuclear monolayers (prepared by treating attached cells in situ with the neutral detergent Nonidet-P40 at 4 degrees C) were isolated in the presence of the irreversible sulfhydryl blocking reagent iodoacetamide, subsequent treatment with DNase I and RNase A followed by 1.6 M NaCl resulted in structures which were extensively depleted of intranuclear components as assessed by phase contrast microscopy and conventional transmission electron microscopy. These structures contained 12 +/- 4% of the total protein present in the original nuclear monolayers. The lamins and polypeptides with molecular weights comparable to those of actin and vimentin were the predominant polypeptides present on SDS-polyacrylamide gels. Western blotting revealed that less than 5% of the total nuclear topo II molecules were present in these structures. In contrast, when the sulfhydryl cross-linking reagent sodium tetrathionate (NaTT) was substituted for iodoacetamide, the same extraction procedure yielded structures containing components of the nucleolus and an extensive intranuclear network. These structures contained a wide variety of nonlamin, nonhistone nuclear polypeptides including 23 +/- 4% of the total nuclear topo II. SDS-polyacrylamide gel electrophoresis performed under nonreducing conditions revealed that topo II in these nuclear matrices was present as part of a large disulfide cross-linked complex. Treatment of these structures with reducing agents in 1.6 M NaCl released the topo II. In contrast, topo I did not form disulfide cross-linked oligomers and was not detectable in any of these nuclease

  17. Stem cells in cell transplantation.

    Science.gov (United States)

    Sanmartin, Agneta; English, Denis; Sanberg, Paul R

    2006-12-01

    This commentary documents the increased number of stem cell-related research reports recently published in the cell transplantation field in the journal Cell Transplantation. The journal covers a wide range of issues in cell-based therapy and regenerative medicine and is attracting clinical and preclinical articles from around the world. It thereby complements and extends the basic coverage of stem cell physiology reported in Stem Cells and Development. Sections in Cell Transplantation cover neuroscience, diabetes, hepatocytes, bone, muscle, cartilage, skin, vessels, and other tissues, as well as tissue engineering that employs novel methods with stem cells. Clearly, the continued use of biomedical engineering will depend heavily on stem cells, and these two journals are well positioned to provide comprehensive coverage of these developments.

  18. Engineering cell-cell signaling.

    Science.gov (United States)

    Blagovic, Katarina; Gong, Emily S; Milano, Daniel F; Natividad, Robert J; Asthagiri, Anand R

    2013-10-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cells (cell surface engineering and synthetic gene circuits) to modulate juxtacrine cell-cell signaling. In addition, significant progress has been made in elucidating design rules and strategies to modulate juxtacrine signaling on the basis of quantitative, engineering analysis of the mechanical and regulatory role of juxtacrine signals in the context of other cues and physical constraints in the microenvironment. These advances in engineering juxtacrine signaling lay a strong foundation for an integrative approach to utilize synthetic cells, advanced 'chassis' and predictive modeling to engineer the form and function of living tissues.

  19. Cell Motility

    CERN Document Server

    Lenz, Peter

    2008-01-01

    Cell motility is a fascinating example of cell behavior which is fundamentally important to a number of biological and pathological processes. It is based on a complex self-organized mechano-chemical machine consisting of cytoskeletal filaments and molecular motors. In general, the cytoskeleton is responsible for the movement of the entire cell and for movements within the cell. The main challenge in the field of cell motility is to develop a complete physical description on how and why cells move. For this purpose new ways of modeling the properties of biological cells have to be found. This long term goal can only be achieved if new experimental techniques are developed to extract physical information from these living systems and if theoretical models are found which bridge the gap between molecular and mesoscopic length scales. Cell Motility gives an authoritative overview of the fundamental biological facts, theoretical models, and current experimental developments in this fascinating area.

  20. Photovoltaic Cells

    Directory of Open Access Journals (Sweden)

    Karolis Kiela

    2012-04-01

    Full Text Available The article deals with an overview of photovoltaic cells that are currently manufactured and those being developed, including one or several p-n junction, organic and dye-sensitized cells using quantum dots. The paper describes the advantages and disadvantages of various photovoltaic cells, identifies the main parameters, explains the main reasons for the losses that may occur in photovoltaic cells and looks at the ways to minimize them.Article in Lithuanian

  1. 额叶皮层神经干细胞定向诱导分化类神经元的超微结构观察%Study on the ultrastructure of directional differentiation neuron-like cells of temporal lobe cerebral cortex neuron stem cell (NSC)

    Institute of Scientific and Technical Information of China (English)

    喻博; 刘云会; 刘冬娟; 石玉秀; 刘跃华; 杨蓓; 杜喆

    2008-01-01

    目的 研究大鼠额叶皮层神经干细胞(NSC)定向诱导分化类神经元细胞过程中的超微结构变化.方法 取Wistar出生24h新生鼠额叶脑组织加入神经生长因子进行干细胞的原代及继代培养SABC Nestin鉴定并定向培养,于1、3、7d进行扫描电镜观察.结果 神经干细胞诱导分化第7天的类神经元细胞扫描电镜观察可见胞体饱满,有树枝状分支,末端见鸭蹼状膨大的生长;透射电镜下观察可见细胞胞质中有大量的粗面内质网、线粒体与高尔基复体,脂滴糖原颗粒及微丝、微管,核膜、核仁清楚.结论 大脑额叶皮层神经干细胞经定向诱导分化形态学上能够分化成类神经元细胞结构.%Objective To evaluate the ultrastructure on frontal lobe cerebral cortex neuron stem cell ( NSC)in the process of directional differentiation neuron-like cells.Method Newborn Wistar animal in 24 hour was used,and the frontal lobe cerebral cortex tissue was scraped,primary generation and secondary culture with nerve nutrition factor were conducted.Immunochemistry SABC method was used to identify Nestin.Scan electron microscope(SEM)sample was prepared and observed on cover glass which taken from the raise board contain directional differentiation neuron at 1,3,7 day.Results Nearly mature,full soma,dendritic branches,duck palm shape apical cone on the terminal were obviously observed on SEM at 7 days.Some synapse type structure appeared on the cell surface.Organelles,massive RER,Golgi apparatus and the fat drop glycogen pellet was rich on TEM at 7 days.Microfilament and microtubule were in line,big and round nucleolus were clear.All these neuron-like cells characteristic were obvious and easy to see.Conclusions This study indicates that the frontal lobe cerebral cortex nerve stem cell can be directional induced differentiate to neuron-like cells.

  2. Engineering Cell-Cell Signaling

    OpenAIRE

    Blagovic, Katarina; Gong, Emily S.; Milano, Daniel F.; Natividad, Robert J.; Asthagiri, Anand R

    2013-01-01

    Juxtacrine cell-cell signaling mediated by the direct interaction of adjoining mammalian cells is arguably the mode of cell communication that is most recalcitrant to engineering. Overcoming this challenge is crucial for progress in biomedical applications, such as tissue engineering, regenerative medicine, immune system engineering and therapeutic design. Here, we describe the significant advances that have been made in developing synthetic platforms (materials and devices) and synthetic cel...

  3. Stem Cells

    Directory of Open Access Journals (Sweden)

    Madhukar Thakur

    2015-02-01

    Full Text Available Objective: The objective of this presentation is to create awareness of stem cell applications in the ISORBE community and to foster a strategy of how the ISORBE community can disseminate information and promote the use of radiolabeled stem cells in biomedical applications. Methods: The continued excitement in Stem Cells, in many branches of basic and applied biomedical science, stems from the remarkable ability of stem cells to divide and develop into different types of cells in the body. Often called as Magic Seeds, stem cells are produced in bone marrow and circulate in blood, albeit at a relatively low concentration. These virtues together with the ability of stem cells to grow in tissue culture have paved the way for their applications to generate new and healthy tissues and to replace diseased or injured human organs. Although possibilities of stem cell applications are many, much remains yet to be understood of these remarkable magic seeds. Conclusion: This presentation shall briefly cover the origin of stem cells, the pros and cons of their growth and division, their potential application, and shall outline some examples of the contributions of radiolabeled stem cells, in this rapidly growing branch of biomedical science

  4. 越橘花色苷对宫颈癌Hela细胞凋亡及抗氧化能力的影响%Effects of Anthocyanin from Vaccinium uliginosum on cell apoptosis and antioxidation in cervical Hela cells

    Institute of Scientific and Technical Information of China (English)

    姜艳霞; 芦晓静; 徐俊杰; 吕士杰

    2011-01-01

    Objective To research the mechanisms of Anthocyanin from Vaccinium uliginosum on proliferation of cervical cancer Hela cells. Methods Different concentrations of Anthocyanin from Vaccinium uliginosum on Hela cells was done for 48 hours to observe its inhibiting cervical cancer Hela cells and the change of cell tnorpholoy by Gimsa dying was used to observe cell apoptosis by flow cytometry ( Annexin V FITC/PI) and to detect P53 expression by RT-PCR, and detect SOD, GSH and MDA in Hela cells. Results Increasing concentration of anthocyanin from Vaccinium made Hela cell counts lower and rare; cells became small and pyknosis nucleolus by Gimsa staining; with Anthocyanin concentration increasing, apoptosis rate increased by fluorescent dye and P53 expression increase was of significant difference in comparison with control group( P <0.05). 30mg/ml and 40mg/ml of anthocyanin could increase SOD and GSH in the Hela cells, with a significant difference in comparison with control group ( P < 0.05). Conclusion Anthocyanin from Vaccinium uliginosum can inhibit the growth of cervical cancer Hela cells by promoting cell apoptosis and increasing P53 expression and antioxidation.%目的 探讨越橘花色苷对宫颈癌Hela细胞的作用机制.方法 以不同浓度的越橘花色苷作用于宫颈癌Hela细胞48h后,通过Gimsa染色观察越橘花色苷抑制Hela细胞的形态学改变,通过流式双染观察Hela细胞凋亡情况,通过RT-PCR观察Hela内P53的表达,并测定Hela细胞内的SOD、GSH、MDA值.结果 Gimsa染色可见越橘花色苷可使Hela细胞光泽度下降,细胞数减少,稀疏,细胞变小、核固缩.流式双染可见,随着橘花色苷浓度升高,凋亡率升高.与对照组比较,越橘花色苷浓度达到30mg/ml时,P53的表达量最高,差异有统计学意义(P<0.05).与对照组比较,30mg/ml和40mg/ml的越橘花色苷组SOD和GSH含量升高,差异有统计学意义(P<0.05).结论越橘花色苷可通过上调抑癌基因P53的表

  5. Histopathological Observation of Dog Basal Cell Carcinoma%犬基底细胞癌的病理组织学观察

    Institute of Scientific and Technical Information of China (English)

    潘俊斌; 刘博奇; 林凯; 于博

    2012-01-01

    Basal cell carcinoma(BCC) is a common low-degree skin malignant tumor,which is also named erosion ulcers.This paper discusses the main points of clinical pathology diagnosis and differential diagnosis of this carcinoma,in order to provide the basis to improve the level of diagnosis and treatment of basal cell carcinoma.The pathological change includes skin ulcer,hemorrage,massive proliferation of tumor tissues which is divided into irregular lobules.And the cells of tumor reveal spindle and polygons and nearly round,the nucleuses are round and had an obvious karyotheca.There is always one distinct nucleolus which may manifest atypia,and mitotic figure can be discovered sometimes.To sum up,all these characters can be used as the main basis of the BCC,and this diagnosis may provide the help to the future therapy.%基底细胞癌(basal cell carcinoma,BCC)是一种常见的低度皮肤恶性肿瘤,又名基底细胞上皮癌、基底细胞癌和侵蚀性溃疡。本文主要探讨皮肤基底细胞癌的临床病理诊断和鉴别诊断要点,为提高基底细胞癌的诊治水平提供依据。通过病理组织学观察,皮肤破溃、出血,肿瘤细胞成团块状增生,由结缔组织分割为不规则小叶状。细胞呈梭形、多边形及近圆形;细胞核圆形,核膜清晰,有一明显核仁,有一定异形性,偶见分裂相,作为确诊基底细胞肉瘤的主要依据,并对疾病的处理和治疗方法进行了归纳和总结。

  6. Types of Stem Cells

    Science.gov (United States)

    ... Stem Cell Glossary Search Toggle Nav Types of Stem Cells Stem cells are the foundation from which all ... Learn About Stem Cells > Types of Stem Cells Stem cells Stem cells are the foundation for every organ ...

  7. Fuel Cells

    DEFF Research Database (Denmark)

    Smith, Anders; Pedersen, Allan Schrøder

    2014-01-01

    Fuel cells have been the subject of intense research and development efforts for the past decades. Even so, the technology has not had its commercial breakthrough yet. This entry gives an overview of the technological challenges and status of fuel cells and discusses the most promising applications...... of the different types of fuel cells. Finally, their role in a future energy supply with a large share of fluctuating sustainable power sources, e.g., solar or wind, is surveyed....

  8. Stem cells.

    Science.gov (United States)

    Redi, Carlo Alberto; Monti, Manuela; Merico, Valeria; Neri, Tui; Zanoni, Mario; Zuccotti, Maurizio; Garagna, Silvia

    2007-01-01

    The application of stem cells to regenerative medicine is one of the actual hot topics in biomedicine. This research could help the cure of a number of diseases that are affecting a large share of the population. Some good results in cell replacement have already been obtained (infarcted heart, diabetes, Parkinson disease), apart from those of more traditional applications like severe burns and blood tumors. We are now facing crucial questions in stem cell biology. One of the key questions is how a cell begins to proliferate or differentiate. Genome reprogramming, both following nuclear transfer and cytoplast action, will likely highlight some of the molecular mechanisms of cell differentiation and dedifferentiation. In turn, these clues should be useful to the production of populations of reprogrammed cells that could develop into tissues or, in the future, into proper organs. We will overview what stem cells are, what roles they play in normal developmental processes and how stem cells could have the potential to treat diseases.

  9. Fuel Cells

    Science.gov (United States)

    Hawkins, M. D.

    1973-01-01

    Discusses the theories, construction, operation, types, and advantages of fuel cells developed by the American space programs. Indicates that the cell is an ideal small-scale power source characterized by its compactness, high efficiency, reliability, and freedom from polluting fumes. (CC)

  10. Stem Cells

    DEFF Research Database (Denmark)

    Sommerlund, Julie

    2004-01-01

    '. This paper is about tech-noscience, and about the proliferation of connections and interdependencies created by it.More specifically, the paper is about stem cells. Biotechnology in general has the power to capture the imagination. Within the field of biotechnology nothing seems more provocative...... and tantalizing than stem cells, in research, in medicine, or as products....

  11. Sickle cell anemia

    Science.gov (United States)

    ... Anemia - sickle cell; Hemoglobin SS disease (Hb SS); Sickle cell disease Images Red blood cells, sickle cell Red blood cells, normal Red blood ... multiple sickle cells Red blood cells, sickle cells Red blood cells, sickle and ... Heeney MM, Ware RE. Sickle cell disease. In: Orkin SH, Fisher DE, Ginsburg D, Look ...

  12. Bi-Cell Unit for Fuel Cell.

    Science.gov (United States)

    The patent concerns a bi-cell unit for a fuel cell . The bi-cell unit is comprised of two electrode packs. Each of the electrode packs includes an...invention relates in general to a bi-cell unit for a fuel cell and in particular, to a bi-cell unit for a hydrazine-air fuel cell .

  13. Cell, cell, cell: fuel cell applications moving ahead

    Energy Technology Data Exchange (ETDEWEB)

    Ross, E.

    2001-11-01

    Developments in fuel cell technology within the last decade, such as the targeting by major automakers of non-polluting fuel cells as an alternative to the internal combustion engine, are reviewed. For example, Ballard Power Systems of Vancouver is the exclusive supplier to both DaimlerCrysler and the Ford Motor Company of the fuel cell stacks that produce the power in fuel cell systems. Ballard plans the commercial launch of transit bus engines in 2002 and automotive products between 2003 and 2005. The company also sees huge opportunities for fuel cells in stationary and portable power applications. At the same time, the Calgary-based fuel cell division of Energy Ventures Inc. is developing a direct methanol fuel cell that eliminates the intermediate step of 'reforming' methanol into hydrogen that is required in the Ballard process. Energy Ventures targets small niche markets such as small utility vehicles for its direct methanol fuel cell. A completely self-contained fuel cell of this type is expected to be ready in 2002. Solid oxide fuel cells for off-grid remote power units as well as for home heat and power is yet another field of development that will be particularly attractive to operations in remote areas where reliable grid electricity is expensive and hard to obtain. A prototype 2.3 kW residential power system using natural gas was made available by Global Thermoelectric Inc in June 2001; field testing is planned for 2002, with commercial production in late 2003 or 2004. The Calgary-based Snow Leopard Resources Inc plans to use pure hydrogen sulphide obtained from sour natural gas as a hydrogen source. The prime focus of Snow Leopard is on gas plants looking for ways to increase their efficiency, obtain carbon dioxide credits and generate electricity on site. This type of fuel cell also could be of interest to companies with shut-in sour gas since these companies could use the stationary fuel cell system to generate electricity.

  14. Learn About Stem Cells

    Science.gov (United States)

    ... Patient Handbook Stem Cell Glossary Search Toggle Nav Stem Cell Basics Stem cells are the foundation from which ... original cell’s DNA, cytoplasm and cell membrane. About stem cells Stem cells are the foundation of development in ...

  15. Fuel cells

    Directory of Open Access Journals (Sweden)

    D. N. Srivastava

    1962-05-01

    Full Text Available The current state of development of fuel cells as potential power sources is reviewed. Applications in special fields with particular reference to military requirements are pointed out.

  16. Basic domains target protein subunits of the RNase MRP complex to the nucleolus independently of complex association.

    NARCIS (Netherlands)

    Eenennaam, H. van; Heijden, A.G. van der; Janssen, R.J.T.; Venrooij, W.J.W. van; Pruijn, G.J.M.

    2001-01-01

    The RNase MRP and RNase P ribonucleoprotein particles both function as endoribonucleases, have a similar RNA component, and share several protein subunits. RNase MRP has been implicated in pre-rRNA processing and mitochondrial DNA replication, whereas RNase P functions in pre-tRNA processing. Both R

  17. The expressions and of PDGF-B and PDGFR-α in non-small cell lung cancer and its significance%血小板衍生生长因子-B链及受体-α链在非小细胞肺癌中的表达及意义

    Institute of Scientific and Technical Information of China (English)

    吴丽娜; 秦晓松; 李强

    2011-01-01

    We aimed to study the roles of platelet-derived growth factor B chain (PDGF-B) and plateletderived growth factor receptor alpha (PDGFR-α) in non-small cell lung cancer (NSCLC). We detected the expression of PDGF-B and PDGFR-α in 85 cases of NSCLC and 20 cases of normal bronchial epithelium with LSAB immunohistochemical technique. In NSCLC, the expression of PDGF-B was located in cytoplasm and/or nucleolus of tumor cells, while PDGFR-α mainly in cytoplasm, and a few in nucleolus. Compared with normal bronchial epithelium; the expressions of PDGF-B and PDGFR-α were much higher in NSCLC (P < 0.05); the expression of PDGFR-α in well differentiated adenocarcinoma (ADC) of lung was higher than that in poor differentiated ADC (P < 0.05); the expression of PDGF-B in Ⅱ and Ⅲ stages of ADC and squamous carcinoma (SQC) of lung was much higher than that in I stage. The results suggest that PDGF-B/PDGFR-α autocrine-stimulated loop may play a crucial role in the development of NSCLC. And PDGFR-α has a positive relationship with the differentiation of ADC, while PDGF-B has a positive relationship with the clinical stages in ADC and SQC of lung.%目的 探讨血小板衍生生长因子B链(PDGF-B)及受体α链(PDGFR-α)与非小细胞肺癌发生发展的关系.方法 采用免疫组化LSAB法检测PDGF-B、PDGFR-α在85例非小细胞肺癌原发灶以及20例正常支气管黏膜中的表达.结果 PDGF B在非小细胞肺癌(NSCLC)细胞浆和/或细胞核中表达,PDGFR-α主要在NSCLC细胞浆中表达,个别在细胞核表达;与正常支气管粘膜组织相比,PDGF-B、PDGFR-α在NSCLC均过度表达(P<0.05);高分化腺癌组PDGFR-α阳性表达率明显高于低分化腺癌组(P<0.05);Ⅱ、Ⅲ期肺癌组PDGF-B阳性表达率明显高于Ⅰ期肺癌组(P<0.05).结论 PDGF-B/PDGFR-α自分泌刺激环在NSCLC的发生中可能起重要作用;PDGFR-α阳性表达与肺腺癌分化呈正相关;PDGF-B的阳性表达与肺腺癌、鳞癌临床分期呈正相关.

  18. Electrochemical cell

    Science.gov (United States)

    Nagy, Zoltan; Yonco, Robert M.; You, Hoydoo; Melendres, Carlos A.

    1992-01-01

    An electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 90.degree. in either direction while maintaining the working and counter electrodes submerged in the electrolyte.

  19. Fuel cells:

    DEFF Research Database (Denmark)

    Sørensen, Bent

    2013-01-01

    A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil and nucl......A brief overview of the progress in fuel cell applications and basic technology development is presented, as a backdrop for discussing readiness for penetration into the marketplace as a solution to problems of depletion, safety, climate or environmental impact from currently used fossil...

  20. Ultrastructural changes in goat interspecies and intraspecies reconstructed early embryos

    DEFF Research Database (Denmark)

    Tao, Yong; Gheng, Lizi; Zhang, Meiling;

    2008-01-01

    and dispered gradually from the 4-cell period. The nucleolus of GC and GG embryos changed from electron dense to a fibrillo-granular meshwork at the 16-cell stage, showing that nucleus function in the reconstructed embryos was activated. The broken nuclear envelope and multiple nucleoli in one blastomere......- and intraspecies reconstructed embryos have a similar pattern of developmental change to that of in vivo-produced embryos for ZP, rough ER, Gi and nucleolus, but differ for mitochondria, LD, vesicles, nucleus and gap junction development. In particular, the interspecies cloned embryos showed more severe...

  1. CellTracks cell analysis system for rare cell detection

    NARCIS (Netherlands)

    Kagan, Michael T.; Trainer, Michael N.; Bendele, Teresa; Rao, Chandra; Horton, Allen; Tibbe, Arjan G.; Greve, Jan; Terstappen, Leon W.M.M.

    2002-01-01

    The CellTracks system is a Compact Disk-based cell analyzer that, similar to flow cytometry, differentiates cells that are aligned while passing through focused laser beams. In CellTracks, only immuno-magnetically labeled cells are aligned and remain in position for further analysis. This feature is

  2. Sickle Cell Anemia

    Science.gov (United States)

    Sickle cell anemia is a disease in which your body produces abnormally shaped red blood cells. The cells ... red blood cells. This leads to anemia. The sickle cells also get stuck in blood vessels, blocking blood ...

  3. Sickle Cell Disease

    Science.gov (United States)

    ... sickle cell disease?Sickle cell disease, also called sickle cell anemia, is a hereditary condition (which means it runs ... disease, hemoglobin SS disease, hemoglobin synthesis, hemoglobinopathies, ... cell anemia, sickle cell crisis, vaso-occlusive crisis Family Health, ...

  4. Stem Cell Information: Glossary

    Science.gov (United States)

    ... bone, cartilage, stromal cells that support blood formation, fat, and fibrous tissue. Cell-based therapies —Treatment in which stem cells are induced to differentiate into the specific cell type required to repair damaged or destroyed cells or ...

  5. Squamous Cell Carcinoma

    Science.gov (United States)

    ... Kids’ zone Video library Find a dermatologist Squamous cell carcinoma Overview Squamous cell carcinoma: This man's skin ... a squamous cell carcinoma on his face. Squamous cell carcinoma: Overview Squamous cell carcinoma (SCC) is a ...

  6. Electrochemical Cell

    DEFF Research Database (Denmark)

    1999-01-01

    The invention relates to a rechargeable electrochemical cell comprising a negative electrode, an electrolyte and a positive electrode in which the positive electrode structure comprises a lithium cobalt manganese oxide of the composition Li¿2?Co¿y?Mn¿2-y?O¿4? where 0

  7. Potent Cells

    Science.gov (United States)

    Liu, Dennis

    2007-01-01

    It seems hard to believe that Dolly the cloned sheep was born 10 years ago, kindling furious arguments over the prospects and ethics of cloning a human. Today, the controversy over cloning is entwined, often confused, with concerns over the use of human embryonic stem cells. Most people are unclear what cloning is, and they know even less when it…

  8. Photovoltaic cell

    Science.gov (United States)

    Gordon, Roy G.; Kurtz, Sarah

    1984-11-27

    In a photovoltaic cell structure containing a visibly transparent, electrically conductive first layer of metal oxide, and a light-absorbing semiconductive photovoltaic second layer, the improvement comprising a thin layer of transition metal nitride, carbide or boride interposed between said first and second layers.

  9. Pollen Mother Cell Miosis and Male Gametophyte Development of Pumpkin%南瓜花粉母细胞减数分裂及雄配子体发育

    Institute of Scientific and Technical Information of China (English)

    崔群香; 刘卫东; 王倩; 肖木珠

    2012-01-01

    [目的]研究南瓜花粉母细胞的减数分裂及其雄配子体发育过程,以期为南瓜花药培养等方面研究提供一定细胞学依据。[方法]采用爱氏苏木精染色-冬青油透明技术对南瓜”天虹”的花粉母细胞减数分裂及其雄配子体发育过程中细胞结构变化和染色体行为进行了观察研究。[结果]南瓜花粉母细胞在细胞核分裂过程中,核膜核仁于中期I消失,末期I重新出现,此时形成2个新月形的细胞核,两核之间出现成膜体,但未出现细胞壁,该成膜体在中期Ⅱ又逐渐消失,末期Ⅱ重新出现。第2次分裂纺锤体中央离心扩散的成膜体与第1次分裂两核相对的中央界面形成的成膜体相连,小孢子细胞壁向心产生。多数四分体中包含四个子细胞,少数还含有额外的小细胞。单核靠边期核仁由1个分解成2~3个或多个,进入有丝分裂前期,成熟花粉为二细胞型。1.0-2.0cm长花蕾中多数花粉细胞处于单核期,可以将其作为花药或小孢子培养的取材依据。[结论]该研究结果为南瓜细胞遗传学方面的研究奠定了基础。%[Objective] Pollen mother cell miosis and male gametophyte development of pumpkin were observed in this study, to provide some cytological basis for pumpkin anther or microspore culture. [Method] Ehrlich's hematoxylin staining-methyl salicylate clearing technique was used for observation and research of the variation of cell structure and chromosomal behavior during pollen mother cell miosis and male gametophyte development of ‘Tianhong' pumpkin. [Result] The meiosis in pollen moth- er cells of pumpkin was simultaneous cytokinesis. In the process of nuclear division, nuclear membrane and nucleolus of pumpkin pollen mother cells gradually disappeared in the metaphase I and reappeared in telophase I , phragmoplast formed between the two generated crescent-shaped nuclei without cell wall, the phragmoplast

  10. Fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Enomoto, Hirofumi.

    1989-05-22

    This invention aims to maintain a long-term operation with stable cell output characteristics by uniformly supplying an electrolyte from the reserver to the matrix layer over the entire matrix layer, and further to prevent the excessive wetting of the catalyst layer by smoothly absorbing the volume change of the electrolyte, caused by the repeated stop/start-up of the fuel cell, within the reserver system. For this purpose, in this invention, an electrolyte transport layer, which connects with an electrolyte reservor formed at the electrode end, is partly formed between the electrode material and the catalyst layer; a catalyst layer, which faces the electrolyte transport layer, has through-holes, which connect to the matrix, dispersely distributed. The electrolyte-transport layer is a thin sheet of a hydrophilic fibers which are non-wovens of such fibers as carbon, silicon carbide, silicon nitride or inorganic oxides. 11 figs.

  11. Ghost cell lesions

    Directory of Open Access Journals (Sweden)

    E Rajesh

    2015-01-01

    Full Text Available Ghost cells have been a controversy for a long time. Ghost cell is a swollen/enlarged epithelial cell with eosnophilic cytoplasm, but without a nucleus. In routine H and E staining these cells give a shadowy appearance. Hence these cells are also called as shadow cells or translucent cells. The appearance of these cells varies from lesion to lesion involving odontogenic and nonodontogenic lesions. This article review about the origin, nature and significance of ghost cells in different neoplasms.

  12. Low dose actinomycin treatment induces HepG2 cell cycle G2 arrest%低浓度放线菌素D诱导HepG2细胞周期G2阻滞的分子机制研究

    Institute of Scientific and Technical Information of China (English)

    肖建勇; 刘相富; 云径平

    2012-01-01

    Objective; To explore the mechanism of HepG2 cell cycle G2 arrest caused by Actinomycin D treatment. Method: HepG2 cell treated with low dose Actinomycin D for different time durations was analyzed by Flow cytometry. The translocation of Nucleophosmin (NPM) /B23 after low dose Actinomycin D treatment wasobserved by immunofluorescence. The expression changes of B23, P53 and P21 with or without Actinomycin D treatment were detected by western blotting. Result; Low dose Actinomycin D inhibited HepG2 cell growth, and caused cell cycle G2 arrest When exposed to Actinomycin D, NPM translocated from nucleolus to plasma but its expression level showed no remarkable change . Actinomycin D treatment resulted in the upregulations of P53 and P21. Conclusion; Low dose Actinomycin D treatment caused HepG2 cell cycle G2 arrest whose underlying mechanism might relate to the translocation of NPM and upregulation of P53 and P21.%目的:探讨低浓度放线菌素D处理导致HepG2细胞周期G2阻滞的分子机制.方法:应用低浓度放线菌素D处理HepG2细胞不同时间,然后应用流式细胞仪检测HepG2生长周期变化;免疫荧光观察核磷蛋白B23(NPM)定位的变化;免疫印迹法检测NPM及其细胞周期相关蛋白P53和P21表达水平.结果:低浓度放线菌素D能够抑制HepG2细胞生长并使细胞周期阻滞于G2期;在放线菌素D作用下,NPM蛋白表达水平没有明显改变,但出现定位改变,即从核仁移位到核浆;放线菌素D处理引起P53和P21蛋白表达水平上调.结论:低浓度放线菌素D作用HepG2细胞导致细胞周期G2阻滞,其机制可能与NPM移位促使其相互作用靶蛋白P53和P21蛋白水平上调有关.

  13. [Inflammatory dendritic cells].

    Science.gov (United States)

    Segura, Elodie; Amigorena, Sebastian

    2014-01-01

    Dendritic cells are a rare and heterogeneous population of professional antigen-presenting cells. Several murine dendritic cell subpopulations have been identified that differ in their phenotype and functional properties. In the steady state, committed dendritic cell precursors differentiate into lymphoid organ-resident dendritic cells and migratory tissue dendritic cells. During inflammation appears an additional dendritic cell subpopulation that has been termed « inflammatory dendritic cells ». Inflammatory dendritic cells differentiate in situ from monocytes recruited to the site of inflammation. Here, we discuss how mouse inflammatory dendritic cells differ from macrophages and from other dendritic cell populations. Finally, we review recent work on human inflammatory dendritic cells.

  14. Red blood cells, sickle cell (image)

    Science.gov (United States)

    Sickle cell anemia is an inherited blood disease in which the red blood cells produce abnormal pigment (hemoglobin). ... abnormal hemoglobin causes deformity of the red blood cells into crescent or sickle-shapes, as seen in this photomicrograph.

  15. Red blood cells, multiple sickle cells (image)

    Science.gov (United States)

    Sickle cell anemia is an inherited disorder in which abnormal hemoglobin (the red pigment inside red blood cells) is produced. The abnormal hemoglobin causes red blood cells to assume a sickle shape, like the ones seen in this photomicrograph.

  16. CellFinder: a cell data repository

    OpenAIRE

    Stachelscheid, H.; Seltmann, S.; Lekschas, F.; Fontaine, J.F.; Mah, N.; Neves, M.; Andrade-Navarro, M.A.; Leser, U; Kurtz, A.

    2014-01-01

    CellFinder (http://www.cellfinder.org) is a comprehensive one-stop resource for molecular data characterizing mammalian cells in different tissues and in different development stages. It is built from carefully selected data sets stemming from other curated databases and the biomedical literature. To date, CellFinder describes 3394 cell types and 50 951 cell lines. The database currently contains 3055 microscopic and anatomical images, 205 whole-genome expression profiles of 194 cell/tissue t...

  17. Molluscan cells in culture: primary cell cultures and cell lines

    OpenAIRE

    2013-01-01

    In vitro cell culture systems from molluscs have significantly contributed to our basic understanding of complex physiological processes occurring within or between tissue-specific cells, yielding information unattainable using intact animal models. In vitro cultures of neuronal cells from gastropods show how simplified cell models can inform our understanding of complex networks in intact organisms. Primary cell cultures from marine and freshwater bivalve and gastropod species are used as bi...

  18. Stem Cell Basics

    Science.gov (United States)

    ... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... Basics » Stem Cell Basics I. Back to top Stem Cell Basics I. Introduction: What are stem cells, and ...

  19. Basal Cell Carcinoma

    Science.gov (United States)

    ... Kids’ zone Video library Find a dermatologist Basal cell carcinoma Overview Basal cell carcinoma: This skin cancer ... that has received years of sun exposure. Basal cell carcinoma: Overview Basal cell carcinoma (BCC) is the ...

  20. Electrorefining cell evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bronson, M.C.; Thomas, R.L. (ed.)

    1989-04-14

    Operational characteristics of the LANL electrorefining cell, a modified LANL electrorefining cell, and an advanced electrorefining cell (known as the CRAC cell) were determined. Average process yields achieved were: 75% for the LANL cell, 82% for the modified LANL cell, and 86% for the CRAC cell. All product metal from the LANL and modified LANL cells was within foundry specifications. Metal from one run in the CRAC cell exceeded foundry specifications for tantalum. The LANL and modified LANL cells were simple in design and operation, but product separation was more labor intensive than with the CRAC cell. The CRAC cell was more complicated in design but remained relatively simple in operation. A decision analysis concluded that the modified LANL cell was the preferred cell. It was recommended that the modified LANL cell be implemented by the Plutonium Recovery Project at Rocky Flats and that development of the CRAC cell continue. 8 refs., 22 figs., 12 tabs.

  1. Antiparietal cell antibody test

    Science.gov (United States)

    APCA; Anti-gastric parietal cell antibody; Atrophic gastritis - anti-gastric parietal cell antibody; Gastric ulcer - anti-gastric parietal cell antibody; Pernicious anemia - anti-gastric parietal cell antibody; ...

  2. Nucleolar exit of RNF8 and BRCA1 in response to DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Guerra-Rebollo, Marta; Mateo, Francesca; Franke, Kristin [Department of Cell Biology, Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona Science Park, Helix Building, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Huen, Michael S.Y. [Department of Anatomy, Centre for Cancer Research, The University of Hong Kong, L1, Laboratory Block, 21 Sassoon Road, Hong Kong Special Administrative Region (Hong Kong); Lopitz-Otsoa, Fernando; Rodriguez, Manuel S. [Proteomics Unit, CIC bioGUNE CIBERehd, ProteoRed, Technology Park of Bizkaia, Building 801A, 48160 Derio (Spain); Plans, Vanessa [Department of Cell Biology, Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona Science Park, Helix Building, Baldiri Reixac 15-21, 08028 Barcelona (Spain); Thomson, Timothy M., E-mail: titbmc@ibmb.csic.es [Department of Cell Biology, Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona Science Park, Helix Building, Baldiri Reixac 15-21, 08028 Barcelona (Spain)

    2012-11-01

    The induction of DNA double-strand breaks (DSBs) elicits a plethora of responses that redirect many cellular functions to the vital task of repairing the injury, collectively known as the DNA damage response (DDR). We have found that, in the absence of DNA damage, the DSB repair factors RNF8 and BRCA1 are associated with the nucleolus. Shortly after exposure of cells to {gamma}-radiation, RNF8 and BRCA1 translocated from the nucleolus to damage foci, a traffic that was reverted several hours after the damage. RNF8 interacted through its FHA domain with the ribosomal protein RPSA, and knockdown of RPSA caused a depletion of nucleolar RNF8 and BRCA1, suggesting that the interaction of RNF8 with RPSA is critical for the nucleolar localization of these DDR factors. Knockdown of RPSA or RNF8 impaired bulk protein translation, as did {gamma}-irradiation, the latter being partially countered by overexpression of exogenous RNF8. Our results suggest that RNF8 and BRCA1 are anchored to the nucleolus through reversible interactions with RPSA and that, in addition to its known functions in DDR, RNF8 may play a role in protein synthesis, possibly linking the nucleolar exit of this factor to the attenuation of protein synthesis in response to DNA damage. -- Highlights: Black-Right-Pointing-Pointer RNF8 and BRCA1 are associated with the nucleolus of undamaged cells. Black-Right-Pointing-Pointer Upon {gamma}-radiation, RNF8 and BRCA1 are translocated from the nucleolus to damage foci. Black-Right-Pointing-Pointer The ribosomal protein RPSA anchors RNF8 to the nucleolus. Black-Right-Pointing-Pointer RNF8 may play previously unsuspected roles in protein synthesis.

  3. Molluscan cells in culture: primary cell cultures and cell lines.

    Science.gov (United States)

    Yoshino, T P; Bickham, U; Bayne, C J

    2013-06-01

    In vitro cell culture systems from molluscs have significantly contributed to our basic understanding of complex physiological processes occurring within or between tissue-specific cells, yielding information unattainable using intact animal models. In vitro cultures of neuronal cells from gastropods show how simplified cell models can inform our understanding of complex networks in intact organisms. Primary cell cultures from marine and freshwater bivalve and gastropod species are used as biomonitors for environmental contaminants, as models for gene transfer technologies, and for studies of innate immunity and neoplastic disease. Despite efforts to isolate proliferative cell lines from molluscs, the snail Biomphalaria glabrata Say, 1818 embryonic (Bge) cell line is the only existing cell line originating from any molluscan species. Taking an organ systems approach, this review summarizes efforts to establish molluscan cell cultures and describes the varied applications of primary cell cultures in research. Because of the unique status of the Bge cell line, an account is presented of the establishment of this cell line, and of how these cells have contributed to our understanding of snail host-parasite interactions. Finally, we detail the difficulties commonly encountered in efforts to establish cell lines from molluscs and discuss how these difficulties might be overcome.

  4. DNA-cell conjugates

    Science.gov (United States)

    Hsiao, Shih-Chia; Francis, Matthew B.; Bertozzi, Carolyn; Mathies, Richard; Chandra, Ravi; Douglas, Erik; Twite, Amy; Toriello, Nicholas; Onoe, Hiroaki

    2016-05-03

    The present invention provides conjugates of DNA and cells by linking the DNA to a native functional group on the cell surface. The cells can be without cell walls or can have cell walls. The modified cells can be linked to a substrate surface and used in assay or bioreactors.

  5. Molecular Mechanisms of Cell-cell Recognition

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-Huai

    2004-01-01

    Cell-cell recognition is the key for multicellular organisms to survive. This recognition critically depends on protein-protein interactions from opposing cell surfaces. Recent structural investigations reveal unique features of these cell surface receptors and how they interact. These interactions are specific, but usually relatively weak, with more hydrophilic forces involved in binding. The receptors appear to have specialized ways to present their key interacting elements for ligand-binding from the cell surface. Cell-cell contacts are multivalent. A large group of cell surface molecules are engaged in interactions. Characteristic weak interactions make possible for each individual molecule pair within the group to constantly associate-dissociate-reassociate, such that the cell-cell recognition becomes a dynamic process. The immunological synapse is a good example for immune receptors to be orchestrated in performing immunological function in a collective fashion.

  6. Skin Stem Cells in Skin Cell Therapy

    Directory of Open Access Journals (Sweden)

    Mollapour Sisakht

    2015-12-01

    Full Text Available Context Preclinical and clinical research has shown that stem cell therapy is a promising therapeutic option for many diseases. This article describes skin stem cells sources and their therapeutic applications. Evidence Acquisition Compared with conventional methods, cell therapy reduces the surgical burden for patients because it is simple and less time-consuming. Skin cell therapy has been developed for variety of diseases. By isolation of the skin stem cell from the niche, in vitro expansion and transplantation of cells offers a surprising healing capacity profile. Results Stem cells located in skin cells have shown interesting properties such as plasticity, transdifferentiation, and specificity. Mesenchymal cells of the dermis, hypodermis, and other sources are currently being investigated to promote regeneration. Conclusions Because skin stem cells are highly accessible from autologous sources and their immunological profile is unique, they are ideal for therapeutic approaches. Optimization of administrative routes requires more investigation own to the lack of a standard protocol.

  7. Photoelectrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Rauh, R. David (Newton, MA); Boudreau, Robert A. (Norton, MA)

    1983-06-14

    A photoelectrochemical cell comprising a sealed container having a light-transmitting window for admitting light into the container across a light-admitting plane, an electrolyte in the container, a photoelectrode in the container having a light-absorbing surface arranged to receive light from the window and in contact with the electrolyte, the surface having a plurality of spaced portions oblique to the plane, each portion having dimensions at least an order of magnitude larger than the maximum wavelength of incident sunlight, the total surface area of the surface being larger than the area of the plane bounded by the container, and a counter electrode in the container in contact with the electrolyte.

  8. Structure of nucleoli in first-order spermatocytes of selected free-living animal species.

    Science.gov (United States)

    Andraszek, Katarzyna; Gryzińska, Magdalena; Ceranka, Mariola; Larisch, Agnieszka

    2015-10-01

    Nucleoli are the product of the activity of nucleolar organizer regions (NOR) in certain chromosomes. Their main functions are the formation of ribosomal subunits from ribosomal protein molecules and the transcription of genes encoding rRNA. Nucleoli are present in the nuclei of nearly all eukaryotic cells because they contain housekeeping genes. The size and number of nucleoli gradually decrease during spermatogenesis. Some of the material originating in the nucleolus probably migrates to the cytoplasm and takes part in the formation of chromatoid bodies (CB). Nucleolus fragmentation and CB assembly take place at the same stage of spermatogenesis. CB are involved in the formation of the acrosome, the migration of mitochondria to the midpiece, and the formation of the sperm tail fibrous sheath. The aim of the study was to characterize the nucleoli in the early prophase of spermatogenesis in the wild boar and the roe deer. The roe deer cells have larger nucleoli and a larger cell nucleus than the wild boar cells. The area of the nucleolus as a percentage of the total area of the nucleus was larger as well. The coefficients of variation for all parameters were higher in the roe deer. In the wild boar cells the nucleoli were mainly regularly shaped. The size of the nucleolus and the nucleus of the spermatocyte is a species-specific trait associated with karyotype and the number of nucleolar organizer regions in a given species.

  9. nduced pluripotent stem cells and cell therapy

    Directory of Open Access Journals (Sweden)

    Banu İskender

    2013-12-01

    Full Text Available Human embryonic stem cells are derived from the inner cell mass of a blastocyst-stage embryo. They hold a huge promise for cell therapy with their self-renewing ability and pluripotency, which is known as the potential to differentiate into all cell types originating from three embryonic germ layers. However, their unique pluripotent feature could not be utilised for therapeutic purposes due to the ethical and legal problems during derivation. Recently, it was shown that the cells from adult tissues could be reverted into embryonic state, thereby restoring their pluripotent feature. This has strenghtened the possiblity of directed differentition of the reprogrammed somatic cells into the desired cell types in vitro and their use in regenerative medicine. Although these cells were termed as induced pluripotent cells, the mechanism of pluripotency has yet to be understood. Still, induced pluripotent stem cell technology is considered to be significant by proposing novel approaches in disease modelling, drug screening and cell therapy. Besides their self-renewing ability and their potential to differentiate into all cell types in a human body, they arouse a great interest in scientific world by being far from the ethical concerns regarding their embryonic counterparts and their unique feature of being patient-specific in prospective cell therapies. In this review, induced pluripotent stem cell technology and its role in cell-based therapies from past to present will be discussed. J Clin Exp Invest 2013; 4 (4: 550-561

  10. Modeling cell-in-cell structure into its biological significance

    OpenAIRE

    He, M-f; Wang, S.; Wang, Y; Wang, X-N.

    2013-01-01

    Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of ‘entering' and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintainin...

  11. 丹参酮IIA对肾癌786-O细胞生长抑制作用及其分子机制%Inhibitive Effect and Molecular Mechanism of Tanshinone IIA on Growth of Renal Carcinoma Cell 786-O

    Institute of Scientific and Technical Information of China (English)

    肖建勇; 谭宇蕙; 张广献

    2012-01-01

    Objective To explore the inhibitive effect and molecular mechanism of Tanshinone IIA (Tan IIA) on the growth of renal carcinoma cell 786-0. Methods MTT assay was used to detect the vitality of 786-0 cells after treatment with Tan IIA. Flow Cytometry was employed to examine the cell cycle distribution in 786-0 cells induced by Tan IIA. Immunoblotting method was utilized to determine the expression level of target proteins related to cell cycle arrest. The translocation of Nucleophosmin (NPM )/B23 after Tan IIA treatment was observed by confocal microscopy. Results Tan IIA remarkably inhibited 786-0 cells vitality in dose-dependent manner(p< 0.05). The results of cell cycle analysis indicated that 786-0 cells were arrested in S phase after Tan IIA treatment. Furthermore, the upregulation of cyclin A, p53 and its downstream gene p21 in 786-0 cells was shown by Immunoblotting. Translocation of NPM from nucleolus to nucleoplasm was found under confocal microscopy. Conclusion Treatment with Tan IIA can induce 786-0 cell cycle S arrest, and the underlying mechanism might relate to the translocation of NPM and to the upregulation of p53 and p21.%目的 研究丹参酮IIA对肾癌细胞生长抑制作用及其分子机制.方法 MTT法检测丹参酮IIA对肾癌细胞活力影响;流式细胞分析检测丹参酮IIA对肾癌细胞周期阻滞;免疫印迹检测细胞周期阻滞相关靶蛋白蛋白表达水平;激光共聚焦观察核仁蛋白Nucleophosmin (NPM)/B23定位的变化.结果 丹参酮能够呈浓度依赖方式显著抑制肾癌细胞生长活力(P<0.05);细胞周期分析表明丹参酮IIA处理的肾癌细胞阻滞在S期;免疫印迹结果证明丹参酮IIA处理肾癌细胞,cyclin A,p53及其下游基因p21显著上调;激光共聚焦结果表明在丹参酮IIA作用下,NPM蛋白定位从核仁移位到核浆.结论 丹参酮IIA作用786-O细胞导致细胞周期S阻滞,其机制可能与NPM移位促使其相互作用靶蛋白p53和p21蛋白水平上调有关.

  12. Subcellular localization of casein kinase I

    DEFF Research Database (Denmark)

    Grankowski, N; Issinger, O G

    1990-01-01

    An anti-yeast CKI antiserum was shown to cross-react with CKI isolated from Krebs II mouse ascites tumour cells. The mammalian CKI showed virtually the same molecular mass (app. 45 kDa) as the yeast enzyme. By immunofluorescence it could be shown that CKI is preferably located in the nucleolus....

  13. Tumor cell "dead or alive": caspase and survivin regulate cell death, cell cycle and cell survival.

    Science.gov (United States)

    Suzuki, A; Shiraki, K

    2001-04-01

    Cell death and cell cycle progression are two sides of the same coin, and these two different phenomenons are regulated moderately to maintain the cellular homeostasis. Tumor is one of the disease states produced as a result of the disintegrated regulation and is characterized as cells showing an irreversible progression of cell cycle and a resistance to cell death signaling. Several investigations have been performed for the understanding of cell death or cell cycle, and cell death research has remarkably progressed in these 10 years. Caspase is a nomenclature referring to ICE/CED-3 cysteine proteinase family and plays a central role during cell death. Recently, several investigations raised some possible hypotheses that caspase is also involved in cell cycle regulation. In this issue, therefore, we review the molecular basis of cell death and cell cycle regulated by caspase in tumor, especially hepatocellular carcinoma cells.

  14. Cell culture purity issues and DFAT cells

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Shengjuan [College of Animal Science and Technology, Northwest A and F University, Yangling, Shaanxi Province 712100 (China); Department of Animal Sciences, Washington State University, Pullman, WA 99164 (United States); Bergen, Werner G. [Program in Cellular and Molecular Biosciences/Department of Animal Sciences, Auburn University, Auburn, AL 36849 (United States); Hausman, Gary J. [Animal Science Department, University of Georgia, Athens, GA 30602-2771 (United States); Zan, Linsen, E-mail: zanls@yahoo.com.cn [College of Animal Science and Technology, Northwest A and F University, Yangling, Shaanxi Province 712100 (China); Dodson, Michael V., E-mail: dodson@wsu.edu [Department of Animal Sciences, Washington State University, Pullman, WA 99164 (United States)

    2013-04-12

    Highlights: •DFAT cells are progeny cells derived from dedifferentiated mature adipocytes. •Common problems in this research is potential cell contamination of initial cultures. •The initial cell culture purity is crucial in DFAT cell research field. -- Abstract: Dedifferentiation of mature adipocytes, in vitro, has been pursued/documented for over forty years. The subsequent progeny cells are named dedifferentiated adipocyte-derived progeny cells (DFAT cells). DFAT cells are proliferative and likely to possess mutilineage potential. As a consequence, DFAT cells and their progeny/daughter cells may be useful as a potential tool for various aspects of tissue engineering and as potential vectors for the alleviation of several disease states. Publications in this area have been increasing annually, but the purity of the initial culture of mature adipocytes has seldom been documented. Consequently, it is not always clear whether DFAT cells are derived from dedifferentiated mature (lipid filled) adipocytes or from contaminating cells that reside in an impure culture.

  15. Electrochemical cell

    Energy Technology Data Exchange (ETDEWEB)

    Heuts, J.J.F.G.; Willems, J.J.G.S.A.

    1987-10-13

    An electrochemical cell is described comprising a negative electrode. The electrochemically active material of which consists of an intermetallic compound forming a hydride with hydrogen, which compound has the CaCu/sub 5/-structure and the compositional formula AB/sub m/C/sub n/, where m+n is between 4.8 and 5.4, where n is between 0.05 and 0.6, in which A consists of Misch-metal or of one or more elements selected from the group consisting of Y, Ti, Hf, Zr, Ca, Th, La and the remaining rare earth metals, in which the total atomic quantities of the elements Y, Ti, Hf and Zr may not be more than 40% of A. B consists of two or more elements selected from the group formed by Ni, Co, Cu, Fe and Mn, where the maximum atomic quantity per gram atom of A is for Ni: 3.5, for Co:3.5, for Cu:3.5, for Fe:2.0 and for Mn:1.0, and C consists of one or more elements selected from the group formed by Al, Cr and Si in the indicated atomic quantities: Al:0.05-0.6, Cr:0.05-0.5 and Si:0.05-0.5, characterized in that the electrochemically active material additionally comprises one or more metals selected from the group formed by Pd, Pt, Ir and Rh, the atomic quantity per gram atom of A being from 0.001 to 0.5.

  16. CELL RESEARCH

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    REVIEWSInducible resistance to Fas-mediated apoptosis in B cells…………………………………ROTHSTEIN Thomas L (245)Executionary pathway for apoptosis: lessons from mutant mice………………………………………WOO Minna, Razqallah Hakem, Tak W Mak (267)The SHP-2 tyrosine phosphatase: Signaling mechanisms and biological functions…………………………………QU Cheng Kui (279)REGULAR ARTICLESTemperature dependent expression of cdc2 and cyclin B1 in spermatogenic cells during spermatogenesis…………………………KONG Wei Hua, Zheng GU, Jining LU, Jiake TSO (289)Transgenic mice overexpressing γ-aminobutyric acid transporter subtype I develop obesity…………………………………MA Ying Hua, Jia Hua HU, Xiao Gang ZHOU, Ruo Wang ZENG, Zhen Tong MEI, Jian FEI, Li He GUO (303)Genetic aberration in primary hepatocellular carcinoma: correlation between p53 gene mutation and loss-of-heterozygosity on chromosome 16q21-q23 and 9p21-p23………………………………………WANG Gang, Chang Hui HUANG, Yan ZHAO, Ling CAI, Ying WANG, Shi Jin XIU, Zheng Wen JIANG, Shuang YANG, Xin Tai ZHAO, Wei HUANG, Jian Ren GU (311)Identification and genetic mapping of four novel genes that regulate leaf deve- lopment in Arabidopsis………………………………………………SUN Yue, Wei ZHANG, Feng Ling LI, Ying Li GUO, Tian Lei LIU, Hai HUANG (325)NOTICE FOR CONTRIBUTORS…………………………………(337)CONTENTS of Vol. 10, 2000…………………………………………………(338)

  17. Cell culture purity issues and DFAT cells.

    Science.gov (United States)

    Wei, Shengjuan; Bergen, Werner G; Hausman, Gary J; Zan, Linsen; Dodson, Michael V

    2013-04-12

    Dedifferentiation of mature adipocytes, in vitro, has been pursued/documented for over forty years. The subsequent progeny cells are named dedifferentiated adipocyte-derived progeny cells (DFAT cells). DFAT cells are proliferative and likely to possess mutilineage potential. As a consequence, DFAT cells and their progeny/daughter cells may be useful as a potential tool for various aspects of tissue engineering and as potential vectors for the alleviation of several disease states. Publications in this area have been increasing annually, but the purity of the initial culture of mature adipocytes has seldom been documented. Consequently, it is not always clear whether DFAT cells are derived from dedifferentiated mature (lipid filled) adipocytes or from contaminating cells that reside in an impure culture.

  18. Cell Membrane Softening in Cancer Cells

    Science.gov (United States)

    Schmidt, Sebastian; Händel, Chris; Käs, Josef

    Biomechanical properties are useful characteristics and regulators of the cell's state. Current research connects mechanical properties of the cytoskeleton to many cellular processes but does not investigate the biomechanics of the plasma membrane. We evaluated thermal fluctuations of giant plasma membrane vesicles, directly derived from the plasma membranes of primary breast and cervical cells and observed a lowered rigidity in the plasma membrane of malignant cells compared to non-malignant cells. To investigate the specific role of membrane rigidity changes, we treated two cell lines with the Acetyl-CoA carboxylase inhibitor Soraphen A. It changed the lipidome of cells and drastically increased membrane stiffness by up regulating short chained membrane lipids. These altered cells had a decreased motility in Boyden chamber assays. Our results indicate that the thermal fluctuations of the membrane, which are much smaller than the fluctuations driven by the cytoskeleton, can be modulated by the cell and have an impact on adhesion and motility.

  19. Mammary stem cells have myoepithelial cell properties.

    Science.gov (United States)

    Prater, Michael D; Petit, Valérie; Alasdair Russell, I; Giraddi, Rajshekhar R; Shehata, Mona; Menon, Suraj; Schulte, Reiner; Kalajzic, Ivo; Rath, Nicola; Olson, Michael F; Metzger, Daniel; Faraldo, Marisa M; Deugnier, Marie-Ange; Glukhova, Marina A; Stingl, John

    2014-10-01

    Contractile myoepithelial cells dominate the basal layer of the mammary epithelium and are considered to be differentiated cells. However, we observe that up to 54% of single basal cells can form colonies when seeded into adherent culture in the presence of agents that disrupt actin-myosin interactions, and on average, 65% of the single-cell-derived basal colonies can repopulate a mammary gland when transplanted in vivo. This indicates that a high proportion of basal myoepithelial cells can give rise to a mammary repopulating unit (MRU). We demonstrate that myoepithelial cells, flow-sorted using two independent myoepithelial-specific reporter strategies, have MRU capacity. Using an inducible lineage-tracing approach we follow the progeny of myoepithelial cells that express α-smooth muscle actin and show that they function as long-lived lineage-restricted stem cells in the virgin state and during pregnancy.

  20. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL) Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  1. Cell sheet engineering

    Directory of Open Access Journals (Sweden)

    Masayuki Yamato

    2004-05-01

    Full Text Available We have developed ‘cell sheet engineering’ in order to avoid the limitations of tissue reconstruction using biodegradable scaffolds or single cell suspension injection. Our concept is tissue reconstruction, not from single cells, but from cell sheets. Cell sheets are prepared using temperature-responsive culture dishes. Temperature-responsive polymers are covalently grafted onto the dishes, allowing various types of cells to adhere and proliferate at 37°C. The cells spontaneously detach when the temperature is reduced below 32°C without the need for proteolytic enzymes. The confluent cells are noninvasively harvested as single, contiguous cell sheets with intact cell-cell junctions and deposited extracellular matrix (ECM. We have used these harvested cell sheets for various tissue reconstructions, including ocular surfaces, periodontal ligaments, cardiac patches, and bladder augmentation.

  2. Lung cancer - small cell

    Science.gov (United States)

    Cancer - lung - small cell; Small cell lung cancer; SCLC ... About 15% of all lung cancer cases are SCLC. Small cell lung cancer is slightly more common in men than women. Almost all cases of SCLC are ...

  3. GSPEL - Fuel Cell Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Fuel Cell Lab (FCL)Provides testing for technology readiness of fuel cell systems The FCL investigates, tests and verifies the performance of fuel-cell systems...

  4. Fuel cells: A survey

    Science.gov (United States)

    Crowe, B. J.

    1973-01-01

    A survey of fuel cell technology and applications is presented. The operating principles, performance capabilities, and limitations of fuel cells are discussed. Diagrams of fuel cell construction and operating characteristics are provided. Photographs of typical installations are included.

  5. CellFinder: a cell data repository.

    Science.gov (United States)

    Stachelscheid, Harald; Seltmann, Stefanie; Lekschas, Fritz; Fontaine, Jean-Fred; Mah, Nancy; Neves, Mariana; Andrade-Navarro, Miguel A; Leser, Ulf; Kurtz, Andreas

    2014-01-01

    CellFinder (http://www.cellfinder.org) is a comprehensive one-stop resource for molecular data characterizing mammalian cells in different tissues and in different development stages. It is built from carefully selected data sets stemming from other curated databases and the biomedical literature. To date, CellFinder describes 3394 cell types and 50 951 cell lines. The database currently contains 3055 microscopic and anatomical images, 205 whole-genome expression profiles of 194 cell/tissue types from RNA-seq and microarrays and 553 905 protein expressions for 535 cells/tissues. Text mining of a corpus of >2000 publications followed by manual curation confirmed expression information on ∼900 proteins and genes. CellFinder's data model is capable to seamlessly represent entities from single cells to the organ level, to incorporate mappings between homologous entities in different species and to describe processes of cell development and differentiation. Its ontological backbone currently consists of 204 741 ontology terms incorporated from 10 different ontologies unified under the novel CELDA ontology. CellFinder's web portal allows searching, browsing and comparing the stored data, interactive construction of developmental trees and navigating the partonomic hierarchy of cells and tissues through a unique body browser designed for life scientists and clinicians.

  6. Snail modulates cell metabolism in MDCK cells

    Energy Technology Data Exchange (ETDEWEB)

    Haraguchi, Misako, E-mail: haraguci@m3.kufm.kagoshima-u.ac.jp [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Indo, Hiroko P. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Iwasaki, Yasumasa [Health Care Center, Kochi University, Kochi 780-8520 (Japan); Iwashita, Yoichiro [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Fukushige, Tomoko [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Majima, Hideyuki J. [Department of Maxillofacial Radiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Izumo, Kimiko; Horiuchi, Masahisa [Department of Environmental Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Kanekura, Takuro [Department of Dermatology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Furukawa, Tatsuhiko [Department of Molecular Oncology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan); Ozawa, Masayuki [Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima 890-8544 (Japan)

    2013-03-22

    Highlights: ► MDCK/snail cells were more sensitive to glucose deprivation than MDCK/neo cells. ► MDCK/snail cells had decreased oxidative phosphorylation, O{sub 2} consumption and ATP content. ► TCA cycle enzyme activity, but not expression, was lower in MDCK/snail cells. ► MDCK/snail cells showed reduced PDH activity and increased PDK1 expression. ► MDCK/snail cells showed reduced expression of GLS2 and ACLY. -- Abstract: Snail, a repressor of E-cadherin gene transcription, induces epithelial-to-mesenchymal transition and is involved in tumor progression. Snail also mediates resistance to cell death induced by serum depletion. By contrast, we observed that snail-expressing MDCK (MDCK/snail) cells undergo cell death at a higher rate than control (MDCK/neo) cells in low-glucose medium. Therefore, we investigated whether snail expression influences cell metabolism in MDCK cells. Although gylcolysis was not affected in MDCK/snail cells, they did exhibit reduced pyruvate dehydrogenase (PDH) activity, which controls pyruvate entry into the tricarboxylic acid (TCA) cycle. Indeed, the activity of multiple enzymes involved in the TCA cycle was decreased in MDCK/snail cells, including that of mitochondrial NADP{sup +}-dependent isocitrate dehydrogenase (IDH2), succinate dehydrogenase (SDH), and electron transport Complex II and Complex IV. Consequently, lower ATP content, lower oxygen consumption and increased survival under hypoxic conditions was also observed in MDCK/snail cells compared to MDCK/neo cells. In addition, the expression and promoter activity of pyruvate dehydrogenase kinase 1 (PDK1), which phosphorylates and inhibits the activity of PDH, was increased in MDCK/snail cells, while expression levels of glutaminase 2 (GLS2) and ATP-citrate lyase (ACLY), which are involved in glutaminolysis and fatty acid synthesis, were decreased in MDCK/snail cells. These results suggest that snail modulates cell metabolism by altering the expression and activity of

  7. Cell aggregation and sedimentation.

    Science.gov (United States)

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  8. Cell control report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This extensive report provides an essential overview of cells and their use as factory automation building blocks. The following issues are discussed in depth: Cell integration Cell software and standards Future technologies applied to cells Plus Cell control applications including: - rotary parts manufacturing - diesel engine component development - general cell control development at the General Electric Corporation - a vendor list.

  9. Nanostructured Solar Cells

    Science.gov (United States)

    Chen, Guanying; Ning, Zhijun; Ågren, Hans

    2016-01-01

    We are glad to announce the Special Issue “Nanostructured Solar Cells”, published in Nanomaterials. This issue consists of eight articles, two communications, and one review paper, covering major important aspects of nanostructured solar cells of varying types. From fundamental physicochemical investigations to technological advances, and from single junction solar cells (silicon solar cell, dye sensitized solar cell, quantum dots sensitized solar cell, and small molecule organic solar cell) to tandem multi-junction solar cells, all aspects are included and discussed in this issue to advance the use of nanotechnology to improve the performance of solar cells with reduced fabrication costs.

  10. Squamous cell skin cancer

    Science.gov (United States)

    ... that reflect light more, such as water, sand, concrete, and areas that are painted white. The higher ... - skin - squamous cell; Skin cancer - squamous cell; Nonmelanoma skin cancer - squamous ...

  11. Gradual reduction in rRNA transcription triggers p53 acetylation and apoptosis via MYBBP1A.

    Science.gov (United States)

    Kumazawa, Takuya; Nishimura, Kazuho; Katagiri, Naohiro; Hashimoto, Sayaka; Hayashi, Yuki; Kimura, Keiji

    2015-06-05

    The nucleolus, whose primary function is ribosome biogenesis, plays an essential role in p53 activation. Ribosome biogenesis is inhibited in response to cellular stress and several nucleolar proteins translocate from the nucleolus to the nucleoplasm, where they activate p53. In this study, we analysed precisely how impaired ribosome biogenesis regulates the activation of p53 by depleting nucleolar factors involved in rRNA transcription or rRNA processing. Nucleolar RNA content decreased when rRNA transcription was inhibited. In parallel with the reduced levels of nucleolar RNA content, the nucleolar protein Myb-binding protein 1 A (MYBBP1A) translocated to the nucleoplasm and increased p53 acetylation. The acetylated p53 enhanced p21 and BAX expression and induced apoptosis. In contrast, when rRNA processing was inhibited, MYBBP1A remained in the nucleolus and nonacetylated p53 accumulated, causing cell cycle arrest at the G1 phase by inducing p21 but not BAX. We propose that the nucleolus functions as a stress sensor to modulate p53 protein levels and its acetylation status, determining cell fate between cell cycle arrest and apoptosis by regulating MYBBP1A translocation.

  12. Cell mechanics: a dialogue

    Science.gov (United States)

    Tao, Jiaxiang; Li, Yizeng; Vig, Dhruv K.; Sun, Sean X.

    2017-03-01

    Under the microscope, eukaryotic animal cells can adopt a variety of different shapes and sizes. These cells also move and deform, and the physical mechanisms driving these movements and shape changes are important in fundamental cell biology, tissue mechanics, as well as disease biology. This article reviews some of the basic mechanical concepts in cells, emphasizing continuum mechanics description of cytoskeletal networks and hydrodynamic flows across the cell membrane. We discuss how cells can generate movement and shape changes by controlling mass fluxes at the cell boundary. These mass fluxes can come from polymerization/depolymerization of actin cytoskeleton, as well as osmotic and hydraulic pressure-driven flow of water across the cell membrane. By combining hydraulic pressure control with force balance conditions at the cell surface, we discuss a quantitative mechanism of cell shape and volume control. The broad consequences of this model on cell mechanosensation and tissue mechanics are outlined.

  13. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Varga, Nora [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Vereb, Zoltan; Rajnavoelgyi, Eva [Department of Immunology, Medical and Health Science Centre, University of Debrecen, Debrecen (Hungary); Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Apati, Agota, E-mail: apati@kkk.org.hu [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary)

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  14. T-Cell Lymphoma

    Science.gov (United States)

    Getting the Facts T-Cell Lymphoma Overview Lymphoma is the most common blood cancer. The two main forms of lymphoma are Hodgkin lymphoma ... develop into lymphomas: B-lymphocytes (B-cells) and T-lymphocytes (T-cells). T-cell lymphomas account for ...

  15. Tracking adult stem cells

    NARCIS (Netherlands)

    Snippert, H.J.G.; Clevers, H.

    2011-01-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context,

  16. Insect Cell Culture

    NARCIS (Netherlands)

    Oers, van M.M.; Lynn, D.E.

    2010-01-01

    Insect cell cultures are widely used in studies on insect cell physiology, developmental biology and microbial pathology. In particular, insect cell culture is an indispensable tool for the study of insect viruses. The first continuously growing insect cell cultures were established from lepidoptera

  17. Ganglion cell like cells, diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Anand Shankar Ammanagi

    2013-01-01

    Full Text Available We report a case of cutaneous swelling found on the left anterior axillary fold of a 41-year-old man. Gross examination of specimen excised from the dermis showed a well-circumscribed nodule histologically composed of spindle cells with interspersed ganglion cell like cells. On hematoxylin and eosine (H and E staining it was diagnosed as ganglioneuroma. Ganglioneuromas are rare, benign, fully differentiated tumors that contain mature schwann cells, ganglion cells, fibrous tissue, and nerve fibers. They are commonly found along the paravertebral sympathetic ganglia and sometimes in the adrenal medulla. However primary cutaneous ganglioneuroma is an extremely rare tumor. Immunohistochemical workup revealed a fibroblastic origin and hence the case was diagnosed as fibromatosis with ganglion cell like fibroblasts. This case report suggests that the features considered diagnostic of ganglioneuromas can occur in other cutaneous lesions and, therefore, this diagnosis cannot be offered only on the basis of H and E.

  18. Generation of iPS Cells from Granulosa Cells.

    Science.gov (United States)

    Mao, Jian; Liu, Lin

    2016-01-01

    Various types of somatic cells can be reprogrammed to induced pluripotent stem (iPS) cells. Somatic stem cells may generate iPS cells more efficiently than do differentiated cells. We show that granulosa cells exhibit characteristic of somatic stem cells and can be reprogrammed to iPS cells more efficiently or with few factors. Here, we describe generation of mouse and pig iPS cells from granulosa cells with high efficiency.

  19. B cell helper assays.

    Science.gov (United States)

    Abrignani, Sergio; Tonti, Elena; Casorati, Giulia; Dellabona, Paolo

    2009-01-01

    Activation, proliferation and differentiation of naïve B lymphocytes into memory B cells and plasma cells requires engagement of the B cell receptor (BCR) coupled to T-cell help (1, 2). T cells deliver help in cognate fashion when they are activated upon recognition of specific MHC-peptide complexes presented by B cells. T cells can also deliver help in a non-cognate or bystander fashion, when they do not find specific MHC-peptide complexes on B cells and are activated by alternative mechanisms. T-cell dependent activation of B cells can be studied in vitro by experimental models called "B cell helper assays" that are based on the co-culture of B cells with activated T cells. These assays allow to decipher the molecular bases for productive T-dependent B cell responses. We show here examples of B cell helper assays in vitro, which can be reproduced with any subset of T lymphocytes that displays the appropriate helper signals.

  20. Mast cells enhance T cell activation: Importance of mast cell-derived TNF

    Science.gov (United States)

    Nakae, Susumu; Suto, Hajime; Kakurai, Maki; Sedgwick, Jonathon D.; Tsai, Mindy; Galli, Stephen J.

    2005-05-01

    Mast cells are not only important effector cells in immediate hypersensitivity reactions and immune responses to pathogens but also can contribute to T cell-mediated disorders. However, the mechanisms by which mast cells might influence T cells in such settings are not fully understood. We find that mast cells can enhance proliferation and cytokine production in multiple T cell subsets. Mast cell-dependent enhancement of T cell activation can be promoted by FcRI-dependent mast cell activation, TNF production by both mast cells and T cells, and mast cell-T cell contact. However, at high concentrations of cells, mast cells can promote T cell activation independent of IgE or TNF. Finally, mast cells also can promote T cell activation by means of soluble factors. These findings identify multiple mechanisms by which mast cells can influence T cell proliferation and cytokine production. allergy | asthma | autoimmunity | cytokines | immune response

  1. Sertoli-Leydig cell tumor

    Science.gov (United States)

    Sertoli-stromal cell tumor; Arrhenoblastoma; Androblastoma; Ovarian cancer - Sertoli-Leydig cell tumor ... The Sertoli cells are normally located in the male reproductive glands (the testes). They feed sperm cells. The Leydig cells, also ...

  2. Single cell mechanics of keratinocyte cells.

    Science.gov (United States)

    Lulevich, Valentin; Yang, Hsin-ya; Isseroff, R Rivkah; Liu, Gang-yu

    2010-11-01

    Keratinocytes represent the major cell type of the uppermost layer of human skin, the epidermis. Using AFM-based single cell compression, the ability of individual keratinocytes to resist external pressure and global rupturing forces is investigated and compared with various cell types. Keratinocytes are found to be 6-70 times stiffer than other cell types, such as white blood, breast epithelial, fibroblast, or neuronal cells, and in contrast to other cell types they retain high mechanic strength even after the cell's death. The absence of membrane rupturing peaks in the force-deformation profiles of keratinocytes and their high stiffness during a second load cycle suggests that their unique mechanical resistance is dictated by the cytoskeleton. A simple analytical model enables the quantification of Young's modulus of keratinocyte cytoskeleton, as high as 120-340 Pa. Selective disruption of the two major cytoskeletal networks, actin filaments and microtubules, does not significantly affect keratinocyte mechanics. F-actin is found to impact cell deformation under pressure. During keratinocyte compression, the plasma membrane stretches to form peripheral blebs. Instead of blebbing, cells with depolymerized F-actin respond to pressure by detaching the plasma membrane from the cytoskeleton underneath. On the other hand, the compression force of keratinocytes expressing a mutated keratin (cell line, KEB-7) is 1.6-2.2 times less than that for the control cell line that has normal keratin networks. Therefore, we infer that the keratin intermediate filament network is responsible for the extremely high keratinocyte stiffness and resilience. This could manifest into the rugged protective nature of the human epidermis.

  3. Plant stem cell niches.

    Science.gov (United States)

    Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

    2012-01-01

    Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

  4. Lung Cancer Stem Cells

    Directory of Open Access Journals (Sweden)

    Sharon R. Pine

    2008-01-01

    Full Text Available Lung cancer remains a major cause of cancer-related lethality because of high incidence and recurrence in spite of significant advances in staging and therapies. Recent data indicates that stem cells situated throughout the airways may initiate cancer formation. These putative stem cells maintain protumorigenic characteristics including high proliferative capacity, multipotent differentiation, drug resistance and long lifespan relative to other cells. Stem cell signaling and differentiation pathways are maintained within distinct cancer types, and destabilization of this machinery may participate in maintenance of cancer stem cells. Characterization of lung cancer stem cells is an area of active research and is critical for developing novel therapies. This review summarizes the current knowledge on stem cell signaling pathways and cell markers used to identify the lung cancer stem cells.

  5. What are Stem Cells?

    Directory of Open Access Journals (Sweden)

    Ahmadshah Farhat

    2014-05-01

    Full Text Available   Stem cells are undifferentiated self regenerating multi potential cells. There are three types of stem cells categories by the ability to form after cells and correlated with the body’s development process. Totipotent: these stem cells can form an entire organism such as fertilized egg. Ploripotent: ploripotent cells are those that can form any cell in the body but cannot form an entire organism such as developing embryo’s totipotent cells become ploripotent  Multipotent: Multi potent stem cells are those that can only form specific cells in the body such as blood cells based. Based on the sources of stem cells we have three types of these cells: Autologous: Sources of the patient own cells are (Autologous either the cells from patient own body or his or her cord blood. For this type of transplant the physician now usually collects the periphery rather than morrow because the procedure is easier on like a bane morrow harvest it take place outside of an operating room, and the patient does not to be under general unsetting . Allogenic: Sources of stem cells from another donore are primarily relatives (familial allogenic or completely unrelated donors. Xenogenic: In these stem cells from different species are transplanted e .g striatal porcine fetal mesan cephalic (FVM xenotransplants for Parkinson’s disease. On sites of isolation such as embryo, umbilical cord and other body tissues stem cells are named embnyonic, cord blood, and adult stem cells. The scope of results and clinical application of stem cells are such as: Neurodegenerative conditions (MS,ALS, Parkinson’s, Stroke, Ocular disorders- Glaucoma, retinitis Pigmentosa (RP, Auto Immune Conditions (Lupus, MS,R. arthritis, Diabetes, etc, Viral Conditions (Hepatitis C and AIDS, Heart Disease, Adrenal Disorders, Injury(Nerve, Brain, etc, Anti aging (hair, skin, weight control, overall well being/preventive, Emotional disorders, Organ / Tissue Cancers, Blood cancers, Blood diseases

  6. Tracking adult stem cells.

    Science.gov (United States)

    Snippert, Hugo J; Clevers, Hans

    2011-02-01

    The maintenance of stem-cell-driven tissue homeostasis requires a balance between the generation and loss of cell mass. Adult stem cells have a close relationship with the surrounding tissue--known as their niche--and thus, stem-cell studies should preferably be performed in a physiological context, rather than outside their natural environment. The mouse is an attractive model in which to study adult mammalian stem cells, as numerous experimental systems and genetic tools are available. In this review, we describe strategies commonly used to identify and functionally characterize adult stem cells in mice and discuss their potential, limitations and interpretations, as well as how they have informed our understanding of adult stem-cell biology. An accurate interpretation of physiologically relevant stem-cell assays is crucial to identify adult stem cells and elucidate how they self-renew and give rise to differentiated progeny.

  7. Stem cells in urology.

    Science.gov (United States)

    Aboushwareb, Tamer; Atala, Anthony

    2008-11-01

    The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem cell research. Instead, scientists have explored other cell sources, including progenitor and stem cells derived from adult tissues and stem cells derived from the amniotic fluid and placenta. In addition, novel techniques for generating stem cells in the laboratory are being developed. These techniques include somatic cell nuclear transfer, in which the nucleus of an adult somatic cell is placed into an oocyte, and reprogramming of adult cells to induce stem-cell-like behavior. Such techniques are now being used in tissue engineering applications, and some of the most successful experiments have been in the field of urology. Techniques to regenerate bladder tissue have reached the clinic, and exciting progress is being made in other areas, such as regeneration of the kidney and urethra. Cell therapy as a treatment for incontinence and infertility might soon become a reality. Physicians should be optimistic that regenerative medicine and tissue engineering will one day provide mainstream treatment options for urologic disorders.

  8. Induction of Functional Hair-Cell-Like Cells from Mouse Cochlear Multipotent Cells

    Directory of Open Access Journals (Sweden)

    Quanwen Liu

    2016-01-01

    Full Text Available In this paper, we developed a two-step-induction method of generating functional hair cells from inner ear multipotent cells. Multipotent cells from the inner ear were established and induced initially into progenitor cells committed to the inner ear cell lineage on the poly-L-lysine substratum. Subsequently, the committed progenitor cells were cultured on the mitotically inactivated chicken utricle stromal cells and induced into hair-cell-like cells containing characteristic stereocilia bundles. The hair-cell-like cells exhibited rapid permeation of FM1-43FX. The whole-cell patch-clamp technique was used to measure the membrane currents of cells differentiated for 7 days on chicken utricle stromal cells and analyze the biophysical properties of the hair-cell-like cells by recording membrane properties of cells. The results suggested that the hair-cell-like cells derived from inner ear multipotent cells were functional following differentiation in an enabling environment.

  9. Cell shape recognition by colloidal cell imprints

    NARCIS (Netherlands)

    Borovička, Josef; Stoyanov, S.D.; Paunov, V.N.

    2015-01-01

    The results presented in this study are aimed at the theoretical estimate of the interactions between a spherical microbial cell and the colloidal cell imprints in terms of the Derjaguin, Landau, Vervey, and Overbeek (DLVO) surface forces. We adapted the Derjaguin approximation to take into accou

  10. Pluripotent Stem Cells for Schwann Cell Engineering

    NARCIS (Netherlands)

    Ma, Ming-San; Boddeke, Erik; Copray, Sjef

    2015-01-01

    Tissue engineering of Schwann cells (SCs) can serve a number of purposes, such as in vitro SC-related disease modeling, treatment of peripheral nerve diseases or peripheral nerve injury, and, potentially, treatment of CNS diseases. SCs can be generated from autologous stem cells in vitro by recapitu

  11. Are mesenchymal stromal cells immune cells?

    NARCIS (Netherlands)

    M.J. Hoogduijn (Martin)

    2015-01-01

    textabstractMesenchymal stromal cells (MSCs) are considered to be promising agents for the treatment of immunological disease. Although originally identified as precursor cells for mesenchymal lineages, in vitro studies have demonstrated that MSCs possess diverse immune regulatory capacities. Pre-cl

  12. The cell cycle as a brake for β-cell regeneration from embryonic stem cells.

    Science.gov (United States)

    El-Badawy, Ahmed; El-Badri, Nagwa

    2016-01-13

    The generation of insulin-producing β cells from stem cells in vitro provides a promising source of cells for cell transplantation therapy in diabetes. However, insulin-producing cells generated from human stem cells show deficiency in many functional characteristics compared with pancreatic β cells. Recent reports have shown molecular ties between the cell cycle and the differentiation mechanism of embryonic stem (ES) cells, assuming that cell fate decisions are controlled by the cell cycle machinery. Both β cells and ES cells possess unique cell cycle machinery yet with significant contrasts. In this review, we compare the cell cycle control mechanisms in both ES cells and β cells, and highlight the fundamental differences between pluripotent cells of embryonic origin and differentiated β cells. Through critical analysis of the differences of the cell cycle between these two cell types, we propose that the cell cycle of ES cells may act as a brake for β-cell regeneration. Based on these differences, we discuss the potential of modulating the cell cycle of ES cells for the large-scale generation of functionally mature β cells in vitro. Further understanding of the factors that modulate the ES cell cycle will lead to new approaches to enhance the production of functional mature insulin-producing cells, and yield a reliable system to generate bona fide β cells in vitro.

  13. Regulatory T cells and B cells: implication on autoimmune diseases

    OpenAIRE

    Wang, Ping; Zheng, Song Guo

    2013-01-01

    The regulatory T (Treg) cells play an important role in the maintenance of homeostasis and the prevention of autoimmune diseases. Although most studies are focusing on the role of Treg cells in T cells and T cells-mediated diseases, these cells also directly affect B cells and other non-T cells. This manuscript updates the role of Treg cells on the B cells and B cell-mediated diseases. In addition, the mechanisms whereby Treg cells suppress B cell responses have been discussed.

  14. FUEL CELL ELECTRODE MATERIALS

    Science.gov (United States)

    FUEL CELL ELECTRODE MATERIALS. RAW MATERIAL SELECTION INFLUENCES POLARIZATION BUT IS NOT A SINGLE CONTROLLING FACTOR. AVAILABLE...DATA INDICATES THAT AN INTERRELATIONSHIP OF POROSITY, AVERAGE PORE VOLUME, AND PERMEABILITY CONTRIBUTES TO ELECTRODE FUEL CELL BEHAVIOR.

  15. NIA Aging Cell Repository

    Data.gov (United States)

    Federal Laboratory Consortium — To facilitate aging research on cells in culture, the NIA provides support for the NIA Aging Cell Repository, located at the Coriell Institute for Medical Research...

  16. Cell signaling review series

    Institute of Scientific and Technical Information of China (English)

    Aiming Lin; Zhenggang Liu

    2008-01-01

    @@ Signal transduction is pivotal for many, if not all, fundamental cellular functions including proliferation, differentiation, transformation and programmed cell death. Deregulation of cell signaling may result in certain types of cancers and other human diseases.

  17. Stem Cell Transplant

    Science.gov (United States)

    ... transplant is a procedure that infuses healthy blood stem cells into your body to replace your damaged or ... A bone marrow transplant is also called a stem cell transplant. A bone marrow transplant may be necessary ...

  18. Sickle cell test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003666.htm Sickle cell test To use the sharing features on this page, please enable JavaScript. The sickle cell test looks for the abnormal hemoglobin in the ...

  19. Sickle Cell Tests

    Science.gov (United States)

    ... AACC products and services. Advertising & Sponsorship: Policy | Opportunities Sickle Cell Tests Share this page: Was this page helpful? ... else I should know? How is it used? Sickle cell tests are used to identify the presence of ...

  20. Sickle Cell Disease Quiz

    Science.gov (United States)

    ... Websites About Us Information For... Media Policy Makers Sickle Cell Disease Quiz Language: English Español (Spanish) Recommend on ... 1. True or False: Only African Americans get sickle cell disease. A True B False 2. True or ...

  1. Sickle Cell Trait

    Science.gov (United States)

    ... Websites About Us Information For... Media Policy Makers Sickle Cell Trait Language: English Español (Spanish) Recommend on Facebook ... pass the trait on to their children. How Sickle Cell Trait is Inherited If both parents have SCT, ...

  2. Sickle cell anemia.

    OpenAIRE

    ŘÍHOVÁ, Tereza

    2013-01-01

    This thesis is about the disease called sickle cell anemia, or drepanocytosis. In this thesis is described the history of the disease, pathophysiology, laboratory features, various clinical features, diferencial diagnosis, quality of life in sickle cell anemia and therapy.

  3. Giant Cell Arteritis

    Science.gov (United States)

    Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...

  4. White Blood Cell Count

    Science.gov (United States)

    ... limited. Home Visit Global Sites Search Help? White Blood Cell Count Share this page: Was this page helpful? ... Count; Leukocyte Count; White Count Formal name: White Blood Cell Count Related tests: Complete Blood Count , Blood Smear , ...

  5. Sickle Cell Information Center

    Science.gov (United States)

    ... Nature, Wash Post, SciAm, CNN - Google Custom Search Sickle Cell Anemia News -- ScienceDaily January 18, 1970 Read articles summarizing medical research on sickle-cell anemia. NYT, Nature, Wash Post, SciAm, CNN - Google Custom ...

  6. Sickle Cell Disease

    Science.gov (United States)

    ... About Us Overview of CDC’s work. Advancements in Sickle Cell Disease New supplement from the American Journal of Preventive Medicine describes the state of sickle cell disease related care in the United States. Read Supplement ...

  7. Red blood cell production

    Science.gov (United States)

    ... to one part of the body or another. Red blood cells are an important element of blood. Their job ... is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow of ...

  8. Cell phone explosion.

    Science.gov (United States)

    Atreya, Alok; Kanchan, Tanuj; Nepal, Samata; Pandey, Bhuwan Raj

    2016-03-01

    Cell phone explosions and resultant burn injuries are rarely reported in the scientific literature. We report a case of cell phone explosion that occurred when a young male was listening to music while the mobile was plugged in for charging.

  9. Mast cell proteoglycans.

    Science.gov (United States)

    Rönnberg, Elin; Melo, Fabio R; Pejler, Gunnar

    2012-12-01

    Mast cells are versatile effector cells of the immune system, contributing to both innate and adaptive immunity toward pathogens but also having profound detrimental activities in the context of inflammatory disease. A hallmark morphological feature of mast cells is their large content of cytoplasmic secretory granules, filled with numerous secretory compounds, including highly negatively charged heparin or chondroitin sulfate proteoglycans of serglycin type. These anionic proteoglycans provide the basis for the strong metachromatic staining properties of mast cells seen when applying various cationic dyes. Functionally, the mast cell proteoglycans have been shown to have an essential role in promoting the storage of other granule-contained compounds, including bioactive monoamines and different mast cell-specific proteases. Moreover, granule proteoglycans have been shown to regulate the enzymatic activities of mast cell proteases and to promote apoptosis. Here, the current knowledge of mast cell proteoglycans is reviewed.

  10. Diagram of Cell to Cell Communication

    Science.gov (United States)

    2002-01-01

    Diagram depicts the importance of cell-cell communication as central to the understanding of cancer growth and progression, the focus of the NASA bioreactor demonstration system (BDS-05) investigation. Microgravity studies will allow us to unravel the signaling and communication between these cells with the host and potential development of therapies for the treatment of cancer metastasis. The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. The Bioreactor is rotated to provide gentle mixing of fresh and spent nutrient without inducing shear forces that would damage the cells. The work is sponsored by NASA's Office of Biological and Physical Research. The bioreactor is managed by the Biotechnology Cell Science Program at NASA's Johnson Space Center (JSC). NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues being cultured in rotating bioreactors by investigators. Credit: Emory University.

  11. STEM CELLS AND PROTEOMICS

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yong-ming; GUO Tian-nan; HUANG Shi-ang

    2006-01-01

    The distinctive features of proteomics are large-scale and high throughput. The key techniques of proteomics are two-dimensional gel electrophoresis, mass spectrometry and bioinformatics. Stem cell can differentiate into all kinds of cells, tissues and organs. There are many proteins and cytokines involved in the process of differentiation. Applying proteomics techniques to the research of the complex process of stem cell differentiation is of great importance to study the mechanism and applications of stem cell differentiation.

  12. Kidney Cell Electrophoresis

    Science.gov (United States)

    Todd, P.

    1985-01-01

    Materials and procedures for microgravity electrophoresis of living human embryonic kidney cells were evaluated, ground support in the form of analytical cell electrophoresis and flow cytometry was provided and cells returned from space flight were analyzed. Preflight culture media, electrophoresis buffer, fraction collection media, temperature profiles, and urokinase assay procedures were tested prior to flight. Electrophoretic mobility distributions of aliquots of the cell population to be fractionated in flight were obtained. The protocol established and utilized is given.

  13. Fish stem cell cultures.

    Science.gov (United States)

    Hong, Ni; Li, Zhendong; Hong, Yunhan

    2011-04-13

    Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES) cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on "Fish Stem Cells and Nuclear Transfer", we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  14. Fish Stem Cell Cultures

    Directory of Open Access Journals (Sweden)

    Ni Hong, Zhendong Li, Yunhan Hong

    2011-01-01

    Full Text Available Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on “Fish Stem Cells and Nuclear Transfer”, we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  15. Increased voltage photovoltaic cell

    Science.gov (United States)

    Ross, B.; Bickler, D. B.; Gallagher, B. D. (Inventor)

    1985-01-01

    A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

  16. Storage of cell lines.

    Science.gov (United States)

    Parker, Katharine A

    2011-01-01

    The successful storage of cell lines depends upon many factors, including the condition of the cells to be frozen and the experience of the operator. Attempting to freeze down unhealthy, contaminated or poorly labelled cells can have huge implications for a research laboratory. This chapter outlines the importance of good record keeping, vigilant monitoring, aseptic technique, and high-quality reagents in the successful storage and downstream propagation of cell lines.

  17. Skeletal (stromal) stem cells

    DEFF Research Database (Denmark)

    Abdallah, Basem M; Kermani, Abbas Jafari; Zaher, Walid

    2015-01-01

    Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy....../preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone....

  18. Stem cell heterogeneity revealed

    DEFF Research Database (Denmark)

    Andersen, Marianne S; Jensen, Kim B

    2016-01-01

    The skin forms a protective, water-impermeable barrier consisting of heavily crosslinked epithelial cells. However, the specific role of stem cells in sustaining this barrier remains a contentious issue. A detailed analysis of the interfollicular epidermis now proposes a model for how a composite...... of cells with different properties are involved in its maintenance....

  19. Advanced Cell Technology, Inc.

    Science.gov (United States)

    Caldwell, William M

    2007-03-01

    Advanced Cell Technology, Inc. (OTCBB: ACTC) is a biotechnology company applying novel human embryonic stem cell technologies in the emerging field of regenerative medicine. We believe that regenerative medicine has the potential to revolutionize the field by enabling scientists to produce human cells of any kind for use in a wide array of therapies.

  20. Adventures with Cell Phones

    Science.gov (United States)

    Kolb, Liz

    2011-01-01

    Teachers are finding creative ways to turn the basic cell phone from a digital distraction into a versatile learning tool. In this article, the author explains why cell phones are important in learning and suggests rather than banning them that they be integrated into learning. She presents activities that can be done on a basic cell phone with a…

  1. Cell phones and cancer

    Science.gov (United States)

    Cancer and cell phones; Do cell phones cause cancer? ... Several major studies show no link between cell phones and cancer at this time. However, since the information available is based on short-term studies, the impact of many years of ...

  2. Nanostructured Organic Solar Cells

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Rubahn, Horst-Günter; Madsen, Morten

    Recent forecasts for alternative energy generation predict emerging importance of supporting state of art photovoltaic solar cells with their organic equivalents. Despite their significantly lower efficiency, number of application niches are suitable for organic solar cells. This work reveals...... the principles of bulk heterojunction organic solar cells fabrication as well as summarises major differences in physics of their operation....

  3. Dazlin' pluripotent stem cells

    NARCIS (Netherlands)

    Welling, M.A.

    2014-01-01

    Pluripotent embryonic stem cells (ESCs) can be isolated from the inner cell mass (ICM) of blastocyst embryos and differentiate into all three germ layers in vitro. However, despite their similar origin, mouse embryonic stem cells represent a more naïve ICM-like pluripotent state whereas human embryo

  4. Mammalian Cell Culture Simplified.

    Science.gov (United States)

    Moss, Robert; Solomon, Sondra

    1991-01-01

    A tissue culture experiment that does not require elaborate equipment and that can be used to teach sterile technique, the principles of animal cell line maintenance, and the concept of cell growth curves is described. The differences between cancerous and normal cells can be highlighted. The procedure is included. (KR)

  5. Cell Culture Made Easy.

    Science.gov (United States)

    Dye, Frank J.

    1985-01-01

    Outlines steps to generate cell samples for observation and experimentation. The procedures (which use ordinary laboratory equipment) will establish a short-term primary culture of normal mammalian cells. Information on culture vessels and cell division and a list of questions to generate student interest and involvement in the topics are…

  6. SYNOVIAL CELL SARCOMA

    Directory of Open Access Journals (Sweden)

    M. Farzan

    1997-06-01

    Full Text Available Ten cases of synovial cell sarcoma are reported. The youngest patient was a 2'A years old boy with synovial cell sarcoma of the knee and the oldest one was a man with synovial cell sarcoma of the elbow.

  7. Embryonic Stem Cell Markers

    Directory of Open Access Journals (Sweden)

    Lan Ma

    2012-05-01

    Full Text Available Embryonic stem cell (ESC markers are molecules specifically expressed in ES cells. Understanding of the functions of these markers is critical for characterization and elucidation for the mechanism of ESC pluripotent maintenance and self-renewal, therefore helping to accelerate the clinical application of ES cells. Unfortunately, different cell types can share single or sometimes multiple markers; thus the main obstacle in the clinical application of ESC is to purify ES cells from other types of cells, especially tumor cells. Currently, the marker-based flow cytometry (FCM technique and magnetic cell sorting (MACS are the most effective cell isolating methods, and a detailed maker list will help to initially identify, as well as isolate ESCs using these methods. In the current review, we discuss a wide range of cell surface and generic molecular markers that are indicative of the undifferentiated ESCs. Other types of molecules, such as lectins and peptides, which bind to ESC via affinity and specificity, are also summarized. In addition, we review several markers that overlap with tumor stem cells (TSCs, which suggest that uncertainty still exists regarding the benefits of using these markers alone or in various combinations when identifying and isolating cells.

  8. Mouse Leydig Tumor Cells

    Directory of Open Access Journals (Sweden)

    Bo-Syong Pan

    2011-01-01

    Full Text Available Cordycepin is a natural pure compound extracted from Cordyceps sinensis (CS. We have demonstrated that CS stimulates steroidogenesis in primary mouse Leydig cell and activates apoptosis in MA-10 mouse Leydig tumor cells. It is highly possible that cordycepin is the main component in CS modulating Leydig cell functions. Thus, our aim was to investigate the steroidogenic and apoptotic effects with potential mechanism of cordycepin on MA-10 mouse Leydig tumor cells. Results showed that cordycepin significantly stimulated progesterone production in dose- and time-dependent manners. Adenosine receptor (AR subtype agonists were further used to treat MA-10 cells, showing that A1, A 2A , A 2B , and A3, AR agonists could stimulate progesterone production. However, StAR promoter activity and protein expression remained of no difference among all cordycepin treatments, suggesting that cordycepin might activate AR, but not stimulated StAR protein to regulate MA-10 cell steroidogenesis. Meanwhile, cordycepin could also induce apoptotic cell death in MA-10 cells. Moreover, four AR subtype agonists induced cell death in a dose-dependent manner, and four AR subtype antagonists could all rescue cell death under cordycepin treatment in MA-10 cells. In conclusion, cordycepin could activate adenosine subtype receptors and simultaneously induce steroidogenesis and apoptosis in MA-10 mouse Leydig tumor cells.

  9. Battery cell module

    Energy Technology Data Exchange (ETDEWEB)

    Shambaugh, J.S.

    1981-11-23

    A modular lithium battery having a plurality of cells, having electrical connecting means connecting the cells to output terminals, and venting means for releasing discharge byproducts to a chemical scrubber is disclosed. Stainless steel cell casings are potted in an aluminum modular case with syntactic foam and epoxy. The wall thickness resulting is about 0.5 inches.

  10. Aneuploidy in stem cells

    NARCIS (Netherlands)

    Garcia-Martinez, Jorge; Bakker, Bjorn; Schukken, Klaske M; Simon, Judith E; Foijer, Floris

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells (IPSCs) from somatic cells has brought this promise steps closer to real

  11. Solar Photovoltaic Cells.

    Science.gov (United States)

    Mickey, Charles D.

    1981-01-01

    Reviews information on solar radiation as an energy source. Discusses these topics: the key photovoltaic material; the bank theory of solids; conductors, semiconductors, and insulators; impurity semiconductors; solid-state photovoltaic cell operation; limitations on solar cell efficiency; silicon solar cells; cadmium sulfide/copper (I) sulfide…

  12. Molecular Mechanisms of HTLV-1 Cell-to-Cell Transmission

    Directory of Open Access Journals (Sweden)

    Christine Gross

    2016-03-01

    Full Text Available The tumorvirus human T-cell lymphotropic virus type 1 (HTLV-1, a member of the delta-retrovirus family, is transmitted via cell-containing body fluids such as blood products, semen, and breast milk. In vivo, HTLV-1 preferentially infects CD4+ T-cells, and to a lesser extent, CD8+ T-cells, dendritic cells, and monocytes. Efficient infection of CD4+ T-cells requires cell-cell contacts while cell-free virus transmission is inefficient. Two types of cell-cell contacts have been described to be critical for HTLV-1 transmission, tight junctions and cellular conduits. Further, two non-exclusive mechanisms of virus transmission at cell-cell contacts have been proposed: (1 polarized budding of HTLV-1 into synaptic clefts; and (2 cell surface transfer of viral biofilms at virological synapses. In contrast to CD4+ T-cells, dendritic cells can be infected cell-free and, to a greater extent, via viral biofilms in vitro. Cell-to-cell transmission of HTLV-1 requires a coordinated action of steps in the virus infectious cycle with events in the cell-cell adhesion process; therefore, virus propagation from cell-to-cell depends on specific interactions between cellular and viral proteins. Here, we review the molecular mechanisms of HTLV-1 transmission with a focus on the HTLV-1-encoded proteins Tax and p8, their impact on host cell factors mediating cell-cell contacts, cytoskeletal remodeling, and thus, virus propagation.

  13. Nucleolar ultrastructure in bovine nuclear transfer embryos

    DEFF Research Database (Denmark)

    Kaňka, Jiří; Smith, Steven Dale; Soloy, Eva

    1999-01-01

    (nonactivated) or S phase (activated) cytoplasts. Control embryos were fixed at the two-, four-, early eight- and late eight-cell stages; nuclear transfer embryos were fixed at 1 and 3 hr post fusion and at the two-, four-, and eight-cell stages. Control embryos possessed a nucleolar precursor body throughout...... at 1 hr after fusion and, by 3 hr after fusion, it was restored again. At this time, the reticulated fibrillo-granular nucleolus had an almost round shape. The nucleolar precursor body seen in the two-cell stage nuclear transfer embryos consisted of intermingled filamentous components and secondary...... time intervals after fusion. In the two-cell stage nuclear transfer embryo, the originally reticulated nucleolus of the donor blastomere had changed into a typical nucleolar precursor body consisting of a homogeneous fibrillar structure. A primary vacuole appeared in the four-cell stage nuclear...

  14. Fuel cell catalyst degradation

    DEFF Research Database (Denmark)

    Arenz, Matthias; Zana, Alessandro

    2016-01-01

    Fuel cells are an important piece in our quest for a sustainable energy supply. Although there are several different types of fuel cells, the by far most popular is the proton exchange membrane fuel cell (PEMFC). Among its many favorable properties are a short start up time and a high power density...... increasing focus. Activity of the catalyst is important, but stability is essential. In the presented perspective paper, we review recent efforts to investigate fuel cell catalysts ex-situ in electrochemical half-cell measurements. Due to the amount of different studies, this review has no intention to give...

  15. Mechanics rules cell biology

    Directory of Open Access Journals (Sweden)

    Wang James HC

    2010-07-01

    Full Text Available Abstract Cells in the musculoskeletal system are subjected to various mechanical forces in vivo. Years of research have shown that these mechanical forces, including tension and compression, greatly influence various cellular functions such as gene expression, cell proliferation and differentiation, and secretion of matrix proteins. Cells also use mechanotransduction mechanisms to convert mechanical signals into a cascade of cellular and molecular events. This mini-review provides an overview of cell mechanobiology to highlight the notion that mechanics, mainly in the form of mechanical forces, dictates cell behaviors in terms of both cellular mechanobiological responses and mechanotransduction.

  16. Transparent ultraviolet photovoltaic cells.

    Science.gov (United States)

    Yang, Xun; Shan, Chong-Xin; Lu, Ying-Jie; Xie, Xiu-Hua; Li, Bing-Hui; Wang, Shuang-Peng; Jiang, Ming-Ming; Shen, De-Zhen

    2016-02-15

    Photovoltaic cells have been fabricated from p-GaN/MgO/n-ZnO structures. The photovoltaic cells are transparent to visible light and can transform ultraviolet irradiation into electrical signals. The efficiency of the photovoltaic cells is 0.025% under simulated AM 1.5 illumination conditions, while it can reach 0.46% under UV illumination. By connecting several such photovoltaic cells in a series, light-emitting devices can be lighting. The photovoltaic cells reported in this Letter may promise the applications in glass of buildings to prevent UV irradiation and produce power for household appliances in the future.

  17. Dental pulp stem cells

    DEFF Research Database (Denmark)

    Ashri, N. Y.; Ajlan, S. A.; Aldahmash, Abdullah M.

    2015-01-01

    scaffold, and guided through signaling molecules. Dental pulp stem cells have been used in an increasing number of studies in dental tissue engineering. Those cells show mesenchymal (stromal) stem cell-like properties including self-renewal and multilineage differentiation potentials, aside from...... an updated review on dental pulp stem cells and their applications in periodontal regeneration, in combination with different scaffolds and growth factors.......Inflammatory periodontal disease is a major cause of loss of tooth-supporting structures. Novel approaches for regeneration of periodontal apparatus is an area of intensive research. Periodontal tissue engineering implies the use of appropriate regenerative cells, delivered through a suitable...

  18. Phase contrast and DIC instrumentation and applications in cell, developmental, and marine biology

    Science.gov (United States)

    Gundlach, Heinz

    1994-05-01

    Nomarski's differential interference contrast (DIC) microscopy is discussed in comparison to Zernike's phase contrast (PhC) microscopy. The possibilities and limits of both are demonstrated by various applications. The high contrast and the use of the full numerical aperture of the DIC optics makes it possible to obtain a series of 'optical sections' through rather thick living specimens (e.g. head of water flea, salivary gland of Drosophila, Xenopus nucleolus, sea urchen egg, mouse embryo). PhC and DIC optics are today available for high resolution light microscopy until N.A. 1.4 Oil as well as for long working distance (LWD) optics, mainly combined with inverted biological microscopes.

  19. Remodeling of ribosomal genes in somatic cells by Xenopus egg extract

    DEFF Research Database (Denmark)

    Østrup, Olga; Hyttel, Poul; Klærke, Dan Arne;

    2011-01-01

    . This occurs within hours of extract treatment and is distinct from a stress response. Egg extract elicits remodeling of the nuclear envelope, chromatin and nucleolus. Nucleolar remodeling involves a rapid and stable decrease in ribosomal gene transcription, and promoter targeting of the nucleolar remodeling...... complex component SNF2H without affecting occupancy of the transcription factor UBF and the stress silencers SUV39H1 and SIRT1. During this process, nucleolar localization of UBF and SIRT1 is not altered. On contrary, azacytidine pre-treatment has an adverse effect on rDNA remodeling induced by extract......Extracts from Xenopus eggs can reprogram gene expression in somatic nuclei, however little is known about the earliest processes associated with the switch in the transcriptional program. We show here that an early reprogramming event is the remodeling of ribosomal chromatin and gene expression...

  20. Fuel Cell/Electrochemical Cell Voltage Monitor

    Science.gov (United States)

    Vasquez, Arturo

    2012-01-01

    A concept has been developed for a new fuel cell individual-cell-voltage monitor that can be directly connected to a multi-cell fuel cell stack for direct substack power provisioning. It can also provide voltage isolation for applications in high-voltage fuel cell stacks. The technology consists of basic modules, each with an 8- to 16-cell input electrical measurement connection port. For each basic module, a power input connection would be provided for direct connection to a sub-stack of fuel cells in series within the larger stack. This power connection would allow for module power to be available in the range of 9-15 volts DC. The relatively low voltage differences that the module would encounter from the input electrical measurement connection port, coupled with the fact that the module's operating power is supplied by the same substack voltage input (and so will be at similar voltage), provides for elimination of high-commonmode voltage issues within each module. Within each module, there would be options for analog-to-digital conversion and data transfer schemes. Each module would also include a data-output/communication port. Each of these ports would be required to be either non-electrical (e.g., optically isolated) or electrically isolated. This is necessary to account for the fact that the plurality of modules attached to the stack will normally be at a range of voltages approaching the full range of the fuel cell stack operating voltages. A communications/ data bus could interface with the several basic modules. Options have been identified for command inputs from the spacecraft vehicle controller, and for output-status/data feeds to the vehicle.

  1. Internalization of NK cells into tumor cells requires ezrin and leads to programmed cell-in-cell death

    Institute of Scientific and Technical Information of China (English)

    Shan Wang; Zhen Guo; Peng Xia; Tingting Liu; Jufang Wang; Shan Li; Lihua Sun; Jianxin Lu; Qian Wen; Mingqian Zhou; Li Ma; Xia Ding; Xiaoning Wang; Xuebiao Yao

    2009-01-01

    Cytotoxic lymphocytes are key players in the orchestration of immune response and elimination of defective cells. We have previously reported that natural killer (NK) cells enter target tumor cells, leading to either target cell death or self-destruction within tumor cells. However, it has remained elusive as to the fate of NK cells after internaliza-tion and whether the heterotypic cell-in-cell process is different from that of the homotypic cell-in-cell event recently named entosis. Here, we show that NK cells undergo a cell-in-cell process with the ultimate fate of apoptosis within tumor cells and reveal that the internalization process requires the actin cytoskeletal regulator, ezrin. To visualize how NK cells enter into tumor cells, we carried out real-time dual color imaging analyses of NK cell internalization into tumor cells. Surprisingly, most NK cells commit to programmed cell death after their entry into tumor cells, which is distinctively different from entosis observed in the homotypic cell-in-cell process. The apoptotic cell death of the internalized NK cells was evident by activation of caspase 3 and DNA fragmentation. Furthermore, NK cell death after internalization is attenuated by the caspase inhibitor, Z-VAD-FMK, confirming apoptosis as the mode of NK cell death within tumor cells. To determine protein factors essential for the entry of NK cells into tumor cells, we car-ried out siRNA-based knockdown analysis and discovered a critical role of ezrin in NK cell internalization. Impor-tantly, PKA-mediated phosphorylation of ezrin promotes the NK cell internalization process. Our findings suggest a novel regulatory mechanism by which ezrin governs NK cell internalization into tumor cells.

  2. Islet cell development.

    Science.gov (United States)

    Rojas, Anabel; Khoo, Adrian; Tejedo, Juan R; Bedoya, Francisco J; Soria, Bernat; Martín, Franz

    2010-01-01

    Over the last years, there has been great success in driving stem cells toward insulin-expressing cells. However, the protocols developed to date have some limitations, such as low reliability and low insulin production. The most successful protocols used for generation of insulin-producing cells from stem cells mimic in vitro pancreatic organogenesis by directing the stem cells through stages that resemble several pancreatic developmental stages. Islet cell fate is coordinated by a complex network of inductive signals and regulatory transcription factors that, in a combinatorial way, determine pancreatic organ specification, differentiation, growth, and lineage. Together, these signals and factors direct the progression from multipotent progenitor cells to mature pancreatic cells. Later in development and adult life, several of these factors also contribute to maintain the differentiated phenotype of islet cells. A detailed understanding of the processes that operate in the pancreas during embryogenesis will help us to develop a suitable source of cells for diabetes therapy. In this chapter, we will discuss the main transcription factors involved in pancreas specification and beta-cell formation.

  3. Cell biology. Metabolic control of cell death.

    Science.gov (United States)

    Green, Douglas R; Galluzzi, Lorenzo; Kroemer, Guido

    2014-09-19

    Beyond their contribution to basic metabolism, the major cellular organelles, in particular mitochondria, can determine whether cells respond to stress in an adaptive or suicidal manner. Thus, mitochondria can continuously adapt their shape to changing bioenergetic demands as they are subjected to quality control by autophagy, or they can undergo a lethal permeabilization process that initiates apoptosis. Along similar lines, multiple proteins involved in metabolic circuitries, including oxidative phosphorylation and transport of metabolites across membranes, may participate in the regulated or catastrophic dismantling of organelles. Many factors that were initially characterized as cell death regulators are now known to physically or functionally interact with metabolic enzymes. Thus, several metabolic cues regulate the propensity of cells to activate self-destructive programs, in part by acting on nutrient sensors. This suggests the existence of "metabolic checkpoints" that dictate cell fate in response to metabolic fluctuations. Here, we discuss recent insights into the intersection between metabolism and cell death regulation that have major implications for the comprehension and manipulation of unwarranted cell loss.

  4. Cell and Tissue Engineering

    CERN Document Server

    2012-01-01

    Cell and Tissue Engineering” introduces the principles and new approaches in cell and tissue engineering. It includes both the fundamentals and the current trends in cell and tissue engineering, in a way useful both to a novice and an expert in the field. The book is composed of 13 chapters all of which are written by the leading experts. It is organized to gradually assemble an insight in cell and tissue function starting form a molecular nano-level, extending to a cellular micro-level and finishing at the tissue macro-level. In specific, biological, physiological, biophysical, biochemical, medical, and engineering aspects are covered from the standpoint of the development of functional substitutes of biological tissues for potential clinical use. Topics in the area of cell engineering include cell membrane biophysics, structure and function of the cytoskeleton, cell-extracellular matrix interactions, and mechanotransduction. In the area of tissue engineering the focus is on the in vitro cultivation of ...

  5. Enteroendocrine cell types revisited

    DEFF Research Database (Denmark)

    Engelstoft, Maja S; Egerod, Kristoffer Lihme; Lund, Mari L

    2013-01-01

    The GI-tract is profoundly involved in the control of metabolism through peptide hormones secreted from enteroendocrine cells scattered throughout the gut mucosa. A large number of recently generated transgenic reporter mice have allowed for direct characterization of biochemical and cell...... biological properties of these previously highly elusive enteroendocrine cells. In particular the surprisingly broad co-expression of six functionally related hormones in the intestinal enteroendocrine cells indicates that it should be possible to control not only the hormone secretion but also the type...... and number of enteroendocrine cells. However, this will require a more deep understanding of the factors controlling differentiation, gene expression and specification of the enteroendocrine cells during their weekly renewal from progenitor cells in the crypts of the mucosa....

  6. Cell Factory Engineering.

    Science.gov (United States)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-03-22

    Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta-review provides general strategy guides for the broad range of applications of rational engineering of cell factories.

  7. Peripheral giant cell granuloma

    Directory of Open Access Journals (Sweden)

    Padam Narayan Tandon

    2012-01-01

    Full Text Available Peripheral giant cell granuloma or the so-called "giant cell epulis" is the most common oral giant cell lesion. It normally presents as a soft tissue purplish-red nodule consisting of multinucleated giant cells in a background of mononuclear stromal cells and extravasated red blood cells. This lesion probably does not represent a true neoplasm, but rather may be reactive in nature, believed to be stimulated by local irritation or trauma, but the cause is not certainly known. This article reports a case of peripheral giant cell granuloma arising at the maxillary anterior region in a 22-year-old female patient. The lesion was completely excised to the periosteum level and there is no residual or recurrent swelling or bony defect apparent in the area of biopsy after a follow-up period of 6 months.

  8. Cell viability assays: introduction.

    Science.gov (United States)

    Stoddart, Martin J

    2011-01-01

    The measurement of cell viability plays a fundamental role in all forms of cell culture. Sometimes it is the main purpose of the experiment, such as in toxicity assays. Alternatively, cell viability can be used to -correlate cell behaviour to cell number, providing a more accurate picture of, for example, anabolic -activity. There are wide arrays of cell viability methods which range from the most routine trypan blue dye exclusion assay to highly complex analysis of individual cells, such as using RAMAN microscopy. The cost, speed, and complexity of equipment required will all play a role in determining the assay used. This chapter aims to provide an overview of many of the assays available today.

  9. The Significance of Studying the Origin of the Cell Nucleus and the Way for Studying%细胞核起源研究的意义和研究途径的探讨

    Institute of Scientific and Technical Information of China (English)

    李靖炎

    2001-01-01

    nucleus.Then,combined the model with the present knowledge on archaea,protists and eukaryotic cells we could establish an all-sided hypothesis on the origin and early evolution of the cell nucleus for further examinations.Further along this way we would closer and closer approach the real evolutionary process.   This is a realistic way.Along this way we have already negated the dinoflagellate nucleus model and the related hypothesis and established the diplomonad nucleus model for the primitive cell nucleus and proposed a rather complete theory on the origin and early revolution of the cell nucleus,including the origins of nuclear envelope,eukaryotic chromosomes and nucleolus (Li,1999).%细胞核的起源是真核细胞进化形成的关键。回顾了过去几十年国内外对细胞核起源问题的探索历程。通过多年的摸索找到了一条切实可行的探索细胞核起源问题的途径。其要点是:在一系列的进化环节中首先抓住原始性的细胞核这一重要环节,探明原始性细胞核的特性,解决了从原始核到典型细胞核的进化问题,原始性细胞核自身的起源问题也就有了基础。为探察原始性细胞核的特性,需要在现存的原生生物中间寻找最原始的类群,然后对它们的细胞核进行尽可能深入地和多方面地研究,对所得结果作进化地分析,以期提出一个原始性细胞核的模型。依据这个模型也就可以对典型细胞核的进化形成和原始核自身的起源作出推论。而这些推论是可以设法加以检验的。不仅可以检验这些推论的正确性,而且对原始核模型的建立也是重要的,可以据之加以发展,修正,甚至否定。沿此途径已经否定了原始性细胞核的涡鞭毛虫核模型,进而提出了双滴虫核模型。

  10. Involvement of plant stem cells or stem cell-like cells in dedifferentiation

    Directory of Open Access Journals (Sweden)

    Fangwei eJiang

    2015-11-01

    Full Text Available Dedifferentiation is the transformation of cells from a given differentiated state to a less differentiated or stem cell-like state. Stem cell-related genes play important roles in dedifferentiation, which exhibits similar histone modification and DNA methylation features to stem cell maintenance. Hence, stem cell-related factors possibly synergistically function to provide a specific niche beneficial to dedifferentiation. During callus formation in Arabidopsis petioles, cells adjacent to procambium cells (stem cell-like cells are dedifferentiated and survive more easily than other cell types. This finding indicates that stem cells or stem cell-like cells may influence the dedifferentiating niche. In this paper, we provide a brief overview of stem cell maintenance and dedifferentiation regulation. We also summarize current knowledge of genetic and epigenetic mechanisms underlying the balance between differentiation and dedifferentiation. Furthermore, we discuss the correlation of stem cells or stem cell-like cells with dedifferentiation.

  11. Stages of Renal Cell Cancer

    Science.gov (United States)

    ... cell cancer is a disease in which malignant (cancer) cells form in tubules of the kidney. Renal cell ... diagnosed, tests are done to find out if cancer cells have spread within the kidney or to other ...

  12. Cutaneous hamartoma with pagetoid cells.

    Science.gov (United States)

    Piérard-Franchimont, C; Dosal, F L; Estrada, J A; Piérard, G E

    1991-04-01

    We report an unusual cutaneous hamartoma with pagetoid cells characterized by the presence of intraepidermal cells resembling Toker's cells of the nipple. These cells were EMA positive and could be related to the histogenesis of some Paget's disease.

  13. Sickle Cell Disease (For Parents)

    Science.gov (United States)

    ... Old Feeding Your 1- to 2-Year-Old Sickle Cell Disease KidsHealth > For Parents > Sickle Cell Disease Print ... healthy, and productive lives. A Closer Look at Sickle Cell Disease The different types of sickle cell disease ...

  14. Membrane Cells for Brine Electrolysis.

    Science.gov (United States)

    Tingle, M.

    1982-01-01

    Membrane cells were developed as alternatives to mercury and diaphragm cells for the electrolysis of brine. Compares the three types of cells, focusing on the advantages and disadvantages of membrane cells. (JN)

  15. High Red Blood Cell Count

    Science.gov (United States)

    Symptoms High red blood cell count By Mayo Clinic Staff A high red blood cell count is an increase in oxygen-carrying cells in your bloodstream. Red blood cells transport oxygen from your lungs to tissues throughout ...

  16. PEROVSKITE SOLAR CELLS (REVIEW ARTICLE)

    OpenAIRE

    Benli, Deniz Ahmet

    2015-01-01

    A solar cell is a device that converts sunlight into electricity. There are different types of solar cells but this report mainly focuses on a type of new generation solar cell that has the name organo-metal halide perovskite, shortly perovskite solar cells. In this respect, the efficiency of power conversion is taken into account to replace the dominancy of traditional and second generation solar cell fields by perovskite solar cells. Perovskite solar cell is a type of solar cell including a...

  17. Cell to substratum and cell to cell interactions of microalgae.

    Science.gov (United States)

    Ozkan, Altan; Berberoglu, Halil

    2013-12-01

    This paper reports the cell to substratum and cell to cell interactions of a diverse group of microalgae based on the Extended Derjaguin, Landau, Verwey, Overbeek (XDLVO) approach using the previously reported physico-chemical surface properties. The microalgae included 10 different species of green algae and diatoms from both freshwater and saltwater environments while the substrata included glass, indium-tin oxide (ITO), stainless steel, polycarbonate, polyethylene, and polystryrene. The results indicated that acid-base interactions were the dominating mechanism of interaction for microalgae. For green algae, if at least one of the interacting surfaces was hydrophobic, adhesion at primary minimum was predicted without any energy barrier. However, most diatom systems featured energy barriers for adhesion due to repulsive van der Waals interactions. The results reported in this study are expected to provide useful data and insight into the interaction mechanisms of microalgae cells with each other and with substrata for a number of practical applications including prevention of biofouling of photobioreactors and other man-made surfaces, promotion of biofilm formation in algal biofilm photobioreactors, and developing bioflocculation strategies for energy efficient harvesting of algal biomass. Particularly, Botryococcus braunii and Cerithiopsis fusiformis were identified as promising species for biofloccuation and biofilm formation in freshwater and saltwater aquatic systems, respectively. Finally, based on the observed trends in this study, use of hydrophilic algae and hydrophilic coatings over surfaces are recommended for minimizing biofouling in aquatic systems.

  18. Biology of Schwann cells.

    Science.gov (United States)

    Kidd, Grahame J; Ohno, Nobuhiko; Trapp, Bruce D

    2013-01-01

    The fundamental roles of Schwann cells during peripheral nerve formation and regeneration have been recognized for more than 100 years, but the cellular and molecular mechanisms that integrate Schwann cell and axonal functions continue to be elucidated. Derived from the embryonic neural crest, Schwann cells differentiate into myelinating cells or bundle multiple unmyelinated axons into Remak fibers. Axons dictate which differentiation path Schwann cells follow, and recent studies have established that axonal neuregulin1 signaling via ErbB2/B3 receptors on Schwann cells is essential for Schwann cell myelination. Extracellular matrix production and interactions mediated by specific integrin and dystroglycan complexes are also critical requisites for Schwann cell-axon interactions. Myelination entails expansion and specialization of the Schwann cell plasma membrane over millimeter distances. Many of the myelin-specific proteins have been identified, and transgenic manipulation of myelin genes have provided novel insights into myelin protein function, including maintenance of axonal integrity and survival. Cellular events that facilitate myelination, including microtubule-based protein and mRNA targeting, and actin based locomotion, have also begun to be understood. Arguably, the most remarkable facet of Schwann cell biology, however, is their vigorous response to axonal damage. Degradation of myelin, dedifferentiation, division, production of axonotrophic factors, and remyelination all underpin the substantial regenerative capacity of the Schwann cells and peripheral nerves. Many of these properties are not shared by CNS fibers, which are myelinated by oligodendrocytes. Dissecting the molecular mechanisms responsible for the complex biology of Schwann cells continues to have practical benefits in identifying novel therapeutic targets not only for Schwann cell-specific diseases but other disorders in which axons degenerate.

  19. Embryonic stem cell-somatic cell fusion and postfusion enucleation.

    Science.gov (United States)

    Sumer, Huseyin; Verma, Paul J

    2015-01-01

    Embryonic stem (ES) cells are able to reprogram somatic cells following cell fusion. The resulting cell hybrids have been shown to have similar properties to pluripotent cells. It has also been shown that transcriptional changes can occur in a heterokaryon, without nuclear hybridization. However it is unclear whether these changes can be sustained following removal of the dominant ES nucleus. In this chapter, methods are described for the cell fusion of mouse tetraploid ES cells with somatic cells and enrichment of the resulting heterokaryons. We next describe the conditions for the differential removal of the ES cell nucleus, allowing for the recovery of somatic cells.

  20. Isolation of rare cancer cells from blood cells using dielectrophoresis.

    Science.gov (United States)

    Salmanzadeh, Alireza; Sano, Michael B; Shafiee, Hadi; Stremler, Mark A; Davalos, Rafael V

    2012-01-01

    In this study, we investigate the application of contactless dielectrophoresis (cDEP) for isolating cancer cells from blood cells. Devices with throughput of 0.2 mL/hr (equivalent to sorting 3×10(6) cells per minute) were used to trap breast cancer cells while allowing blood cells through. We have shown that this technique is able to isolate cancer cells in concentration as low as 1 cancer cell per 10(6) hematologic cells (equivalent to 1000 cancer cells in 1 mL of blood). We achieved 96% trapping of the cancer cells at 600 kHz and 300 V(RMS).

  1. Cell-Substrate Adhesion by Amoeboid Cells

    Science.gov (United States)

    Flanders, Bret; Panta, Krishna

    Amoeboid migration is a rapid (10 μm min-1) mode of migration that some tumor cells exhibit. To permit such rapid movement, the adhesive contacts between the cell and the substrate must be relatively short-lived and weak. In this study, we investigate the basic adhesive character of amoeboid cells (D. discoideum) in contact with silanized glass substrates. We observe the initiation and spreading of the adhesive contacts that these cells establish as they settle under gravity onto the substrate and relax towards mechanical equilibrium. The use of interference reflection microscopy and cellular tethering measurements have allowed us to determine the basic adhesive properties of the cell: the membrane-medium interfacial energy; the bending modulus; the equilibrium contact angle; and the work of adhesion. We find the time scale on which settling occurs to be longer than expected. Implications of these results on adhesion and migration will be discussed. The authors are grateful for support from NSF (CBET-1451903) and NIH (1R21EY026392).

  2. 核仁的细胞辐射应激功能研究进展%Progress in Studies on Nucleolus Functions

    Institute of Scientific and Technical Information of China (English)

    畅磊; 周光明

    2011-01-01

    核仁是细胞核内核糖体合成、加工的场所.最近研究发现核仁参与多种细胞过程,其中最为重要的就是细胞应激反应.核仁作为细胞应激感受器,调控ARF等多种蛋白的定位及P53等关键蛋白的活性等,从而介导细胞的应激反应.对核仁的细胞辐射应激功能研究进展进行了综述.%Nucleoli is the sites for ribosome synthesis and processing, however, recent approaches have revealed that it is also involved in variety of cellular processes, especially the cellular stress response.As sensors, nucleoli regulate the localization of nucleolar proteins, such as ( Alternate Reading Frame,ARF), and the activation of key factors, such as P53, and consequently mediate the cellular stress response.In this paper, recent progress in the studies on nucleolar functions in cellular stress response to radiation is reviewed.

  3. Aneuploidy in stem cells

    Institute of Scientific and Technical Information of China (English)

    Jorge; Garcia-Martinez; Bjorn; Bakker; Klaske; M; Schukken; Judith; E; Simon; Floris; Foijer

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells(IPSCs) from somatic cells has brought this promise steps closer to reality. However,as somatic cells might have accumulated various chromosomal abnormalities,including aneuploidies throughout their lives,the resulting IPSCs might no longer carry the perfect blueprint for the tissue to be generated,or worse,become at risk of adopting a malignant fate. In this review,we discuss the contribution of aneuploidy to healthy tissues and how aneuploidy can lead to disease. Furthermore,we review the differences between how somatic cells and stem cells respond to aneuploidy.

  4. Mechanical plasticity of cells

    Science.gov (United States)

    Bonakdar, Navid; Gerum, Richard; Kuhn, Michael; Spörrer, Marina; Lippert, Anna; Schneider, Werner; Aifantis, Katerina E.; Fabry, Ben

    2016-10-01

    Under mechanical loading, most living cells show a viscoelastic deformation that follows a power law in time. After removal of the mechanical load, the cell shape recovers only incompletely to its original undeformed configuration. Here, we show that incomplete shape recovery is due to an additive plastic deformation that displays the same power-law dynamics as the fully reversible viscoelastic deformation response. Moreover, the plastic deformation is a constant fraction of the total cell deformation and originates from bond ruptures within the cytoskeleton. A simple extension of the prevailing viscoelastic power-law response theory with a plastic element correctly predicts the cell behaviour under cyclic loading. Our findings show that plastic energy dissipation during cell deformation is tightly linked to elastic cytoskeletal stresses, which suggests the existence of an adaptive mechanism that protects the cell against mechanical damage.

  5. Cell Factory Engineering

    DEFF Research Database (Denmark)

    Davy, Anne Mathilde; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-01-01

    Rational approaches to modifying cells to make molecules of interest are of substantial economic and scientific interest. Most of these efforts aim at the production of native metabolites, expression of heterologous biosynthetic pathways, or protein expression. Reviews of these topics have largely...... focused on individual strategies or cell types, but collectively they fall under the broad umbrella of a growing field known as cell factory engineering. Here we condense >130 reviews and key studies in the art into a meta-review of cell factory engineering. We identified 33 generic strategies...... in the field, all applicable to multiple types of cells and products, and proven successful in multiple major cell types. These apply to three major categories: production of native metabolites and/or bioactives, heterologous expression of biosynthetic pathways, and protein expression. This meta...

  6. NCAM regulates cell motility

    DEFF Research Database (Denmark)

    Prag, Søren; Lepekhin, Eugene A; Kolkova, Kateryna

    2002-01-01

    Cell migration is required during development of the nervous system. The regulatory mechanisms for this process, however, are poorly elucidated. We show here that expression of or exposure to the neural cell adhesion molecule (NCAM) strongly affected the motile behaviour of glioma cells...... independently of homophilic NCAM interactions. Expression of the transmembrane 140 kDa isoform of NCAM (NCAM-140) caused a significant reduction in cellular motility, probably through interference with factors regulating cellular attachment, as NCAM-140-expressing cells exhibited a decreased attachment...... to a fibronectin substratum compared with NCAM-negative cells. Ectopic expression of the cytoplasmic part of NCAM-140 also inhibited cell motility, presumably via the non-receptor tyrosine kinase p59(fyn) with which NCAM-140 interacts. Furthermore, we showed that the extracellular part of NCAM acted as a paracrine...

  7. Fish germ cells

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Fish, like many other animals, have two major cell lineages, namely the germline and soma. The germ-soma separation is one of the earliest events of embryonic development. Germ cells can be specifically labeled and isolated for culture and transplan-tation, providing tools for reproduction of endangered species in close relatives, such as surrogate production of trout in salmon. Haploid cell cultures, such as medaka haploid embryonic stem cells have recently been obtained, which are capable of mimicking sperm to produce fertile offspring, upon nuclear being directly transferred into normal eggs. Such fish originated from a mosaic oocyte that had a haploid meiotic nucleus and a transplanted haploid mitotic cell culture nucleus. The first semi-cloned fish is Holly. Here we review the current status and future directions of understanding and manipulating fish germ cells in basic research and reproductive technology.

  8. Trafficking and cell migration.

    Science.gov (United States)

    Ulrich, Florian; Heisenberg, Carl-Philipp

    2009-07-01

    The migration of single cells and epithelial sheets is of great importance for gastrulation and organ formation in developing embryos and, if misregulated, can have dire consequences e.g. during cancer metastasis. A keystone of cell migration is the regulation of adhesive contacts, which are dynamically assembled and disassembled via endocytosis. Here, we discuss some of the basic concepts about the function of endocytic trafficking during cell migration: transport of integrins from the cell rear to the leading edge in fibroblasts; confinement of signalling to the front of single cells by endocytic transport of growth factors; regulation of movement coherence in multicellular sheets by cadherin turnover; and shaping of extracellular chemokine gradients. Taken together, endocytosis enables migrating cells and tissues to dynamically modulate their adhesion and signalling, allowing them to efficiently migrate through their extracellular environment.

  9. Gingival plasma cell granuloma

    Directory of Open Access Journals (Sweden)

    Amitkumar B Pandav

    2012-01-01

    Full Text Available Plasma cell granuloma, also known as inflammatory pseudotumor is a tumor-like lesion that manifests primarily in the lungs. But it may occur in various other anatomic locations like orbit, head and neck, liver and rarely in the oral cavity. We here report an exceedingly rare case of gingival plasma cell granuloma in a 58 year old woman who presented with upper gingival polypoidal growth. The histopathological examination revealed a mass composed of proliferation of benign spindle mesenchymal cells in a loose myxoid and fibrocollagenous stroma along with dense infiltrate of chronic inflammatory cells predominantly containing plasma cells. Immunohistochemistry for kappa and lambda light chains showed a polyclonal staining pattern confirming a diagnosis of plasma cell granuloma.

  10. Gingival plasma cell granuloma

    Directory of Open Access Journals (Sweden)

    Phadnaik Mangesh

    2010-01-01

    Full Text Available Plasma cell granuloma is a rare reactive lesion composed of polyclonal plasma cells. It manifests primarily in the lungs, but may occur in various other anatomic locations like the oral cavity. Intraoral plasma cell granulomas involving the tongue, lip, oral mucosa and gingiva have been reported in the past. This case presents a 54-year-old female with chronic periodontitis and mandibular anterior gingival overgrowth treated by Phase I therapy (scaling and root planing and excisional biopsy. Histological examination revealed inflammatory cell infiltrate containing sheets of plasma cells. Immunohistochemistry for kappa and lambda light chains showed a polyclonal staining pattern confirming a diagnosis of plasma cell granuloma. This case highlights the need to biopsy for unusual lesions to rule out potential neoplasms.

  11. Induced pluripotent stem cells

    Institute of Scientific and Technical Information of China (English)

    Siddhartha Bhowmik; LI Yong

    2011-01-01

    Induced pluripotent stem (iPS) cells are a recent development which has brought a promise of great therapeutic values. The previous technique of somatic cell nuclear transfer (SCNT) has been ineffective in humans. Recent discoveries show that human fibroblasts can be reprogrammed by a transient over expression of a small number of genes; they can undergo induced pluripotency. iPS were first produced in 2006. By 2008, work was underway to remove the potential oncogenes from their structure. In 2009, protein iPS (piPS) cells were discovered. Surface markers and reporter genes play an important role in stem cell research. Clinical applications include generation of self renewing stem cells, tissue replacement and many more. Stem cell therapy has the ability to dramatically change the treatment of human diseases.

  12. Myoepithelial cells in pathology.

    Science.gov (United States)

    Balachander, N; Masthan, K M K; Babu, N Aravindha; Anbazhagan, V

    2015-04-01

    Myoepithelial cells are a normal constituent of the salivary acini and ducts and are found between the epithelial cells and the basement membrane. Microscopically myoepithelial cells are thin and spindle-shaped and ultrastructurally they possess a number of Cytoplasmic processes that extend between and over the acinar and ductal-lining cells, and they show features of both smooth muscle and epithelium. They play a vital role during expulsion of saliva and regulates the electrolytic exchange. They also perform as tumor suppressors and are considered to play a very important role in differentiation of various salivary gland tumors and help in the diagnosis of tumors. Neoplastic myoepithelial cells in both benign and malignant tumors can take numerous forms including epithelioid, plasmacytoid, spindle and clear cell variant, and this variability largely accounts for difficulties in histopathological diagnosis.

  13. Myoepithelial cells in pathology

    Directory of Open Access Journals (Sweden)

    N Balachander

    2015-01-01

    Full Text Available Myoepithelial cells are a normal constituent of the salivary acini and ducts and are found between the epithelial cells and the basement membrane. Microscopically myoepithelial cells are thin and spindle-shaped and ultrastructurally they possess a number of Cytoplasmic processes that extend between and over the acinar and ductal-lining cells, and they show features of both smooth muscle and epithelium. They play a vital role during expulsion of saliva and regulates the electrolytic exchange. They also perform as tumor suppressors and are considered to play a very important role in differentiation of various salivary gland tumors and help in the diagnosis of tumors. Neoplastic myoepithelial cells in both benign and malignant tumors can take numerous forms including epithelioid, plasmacytoid, spindle and clear cell variant, and this variability largely accounts for difficulties in histopathological diagnosis.

  14. Cytoskeleton and Cell Motility

    CERN Document Server

    Risler, Thomas

    2011-01-01

    The present article is an invited contribution to the Encyclopedia of Complexity and System Science, Robert A. Meyers Ed., Springer New York (2009). It is a review of the biophysical mechanisms that underly cell motility. It mainly focuses on the eukaryotic cytoskeleton and cell-motility mechanisms. Bacterial motility as well as the composition of the prokaryotic cytoskeleton is only briefly mentioned. The article is organized as follows. In Section III, I first present an overview of the diversity of cellular motility mechanisms, which might at first glance be categorized into two different types of behaviors, namely "swimming" and "crawling". Intracellular transport, mitosis - or cell division - as well as other extensions of cell motility that rely on the same essential machinery are briefly sketched. In Section IV, I introduce the molecular machinery that underlies cell motility - the cytoskeleton - as well as its interactions with the external environment of the cell and its main regulatory pathways. Sec...

  15. Mammary gland stem cells

    DEFF Research Database (Denmark)

    Fridriksdottir, Agla J R; Petersen, Ole W; Rønnov-Jessen, Lone

    2011-01-01

    Distinct subsets of cells, including cells with stem cell-like properties, have been proposed to exist in normal human breast epithelium and breast carcinomas. The cellular origins of epithelial cells contributing to gland development, tissue homeostasis and cancer are, however, still poorly...... and differences between mouse and human gland development with particular emphasis on the identity and localization of stem cells, and the influence of the surrounding microenvironment. It is concluded that while recent advances in the field have contributed immense insight into how the normal mammary gland...... develops and is maintained, significant discrepancies exist between the mouse and human gland which should be taken into consideration in current and future models of mammary stem cell biology....

  16. Differentiated human stem cells resemble fetal, not adult, β cells.

    Science.gov (United States)

    Hrvatin, Sinisa; O'Donnell, Charles W; Deng, Francis; Millman, Jeffrey R; Pagliuca, Felicia Walton; DiIorio, Philip; Rezania, Alireza; Gifford, David K; Melton, Douglas A

    2014-02-25

    Human pluripotent stem cells (hPSCs) have the potential to generate any human cell type, and one widely recognized goal is to make pancreatic β cells. To this end, comparisons between differentiated cell types produced in vitro and their in vivo counterparts are essential to validate hPSC-derived cells. Genome-wide transcriptional analysis of sorted insulin-expressing (INS(+)) cells derived from three independent hPSC lines, human fetal pancreata, and adult human islets points to two major conclusions: (i) Different hPSC lines produce highly similar INS(+) cells and (ii) hPSC-derived INS(+) (hPSC-INS(+)) cells more closely resemble human fetal β cells than adult β cells. This study provides a direct comparison of transcriptional programs between pure hPSC-INS(+) cells and true β cells and provides a catalog of genes whose manipulation may convert hPSC-INS(+) cells into functional β cells.

  17. Direct hydrocarbon fuel cells

    Science.gov (United States)

    Barnett, Scott A.; Lai, Tammy; Liu, Jiang

    2010-05-04

    The direct electrochemical oxidation of hydrocarbons in solid oxide fuel cells, to generate greater power densities at lower temperatures without carbon deposition. The performance obtained is comparable to that of fuel cells used for hydrogen, and is achieved by using novel anode composites at low operating temperatures. Such solid oxide fuel cells, regardless of fuel source or operation, can be configured advantageously using the structural geometries of this invention.

  18. Lymphomas of large cells.

    Science.gov (United States)

    Staples, W G; Gétaz, E P

    1977-09-03

    Historial aspects of the classification of large-cell lymphomas are described. Immunological characterization of the lymphomas has been made possible by identification of T and B lymphocytes according to their cell membrane surface characteristics. The pathogenesis of lymphomas has been clarified by the germinal (follicular) centre cell concepts of Lennert and Lukes and Collins. The various classifications are presented and compared. Whether these subdivisions will have any relevance in the clinical context remains to be seen.

  19. Immobilized Cell Research

    Science.gov (United States)

    1990-10-31

    beads, the plasmid is twice as stable as in cells In a process where immobilized cells produce material grown in continuous culture over 200...carrageenan) or chemically cross-linked, or- Penicillium chrysogenum than in washed freely suspended ganic polymer (Ca-alginate, polyacrylamide, and mycelium ...these materials are formed into the freely suspended cells stopped after 6 days. If the beads of several millimeters in diameter by allowing the

  20. Cell Wall Proteome

    OpenAIRE

    Boudart, Georges; Minic, Zoran; Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth; Pont-Lezica, Rafael F

    2007-01-01

    In this chapter, we will focus on the contribution of proteomics to the identification and determination of the structure and function of CWPs as well as discussing new perspectives in this area. The great variety of proteins found in the plant cell wall is described. Some families, such as glycoside hydrolases, proteases, lectins, and inhibitors of cell wall modifying enzymes, are discussed in detail. Examples of the use of proteomic techniques to elucidate the structure of various cell wall...

  1. Systems cell biology.

    Science.gov (United States)

    Mast, Fred D; Ratushny, Alexander V; Aitchison, John D

    2014-09-15

    Systems cell biology melds high-throughput experimentation with quantitative analysis and modeling to understand many critical processes that contribute to cellular organization and dynamics. Recently, there have been several advances in technology and in the application of modeling approaches that enable the exploration of the dynamic properties of cells. Merging technology and computation offers an opportunity to objectively address unsolved cellular mechanisms, and has revealed emergent properties and helped to gain a more comprehensive and fundamental understanding of cell biology.

  2. Origins of pluripotent stem cells.

    Science.gov (United States)

    Roelen, B A J; Chuva De Sousa Lopes, S M

    2011-08-01

    Different types of pluripotent stem cells can be identified and cultured in vitro. Here an overview is presented of the various pluripotent stem cells types. Embryonal carcinoma (EC) cells that have been cultured in vitro provided the groundwork for future pluripotent cell cultures. Conditions established for these cells such as culture on a feeder layer of mouse embryonic fibroblasts and the importance of fetal calf serum were initially also used for the culture of mouse embryonic stem (ES) cells derived from the inner cell masses of blastocysts. Embryonic stem cells derived from human blastocysts were found to require different conditions and are cultured in the presence of activin and basic fibroblast growth factor. Recently pluripotent stem cells have also been derived from mouse peri-implantation epiblasts. Since these epiblast stem cells (EpiSCs) require the same conditions as the human ES cells it has been suggested that human ES cells are more similar to mouse EpiSCs than to mouse ES cells. Pluripotent cell lines have also been derived from migratory primordial germ cells and spermatogonial stem cells. The creation of pluripotent stem cells from adult cells by the introduction of reprogramming transcription factors, so-called induced pluripotent stem (iPS) cells allowed the derivation of patient-specific pluripotent stem cells without the need of creation of a human blastocyst after cloning by somatic cells nuclear transfer. Recently it has become clear however that iPS cells may be quite different to ES cells in terms of epigenetics.

  3. High resolution surface plasmon microscopy for cell imaging

    Science.gov (United States)

    Argoul, F.; Monier, K.; Roland, T.; Elezgaray, J.; Berguiga, L.

    2010-04-01

    We introduce a new non-labeling high resolution microscopy method for cellular imaging. This method called SSPM (Scanning Surface Plasmon Microscopy) pushes down the resolution limit of surface plasmon resonance imaging (SPRi) to sub-micronic scales. High resolution SPRi is obtained by the surface plasmon lauching with a high numerical aperture objective lens. The advantages of SPPM compared to other high resolution SPRi's rely on three aspects; (i) the interferometric detection of the back reflected light after plasmon excitation, (ii) the twodimensional scanning of the sample for image reconstruction, (iii) the radial polarization of light, enhancing both resolution and sensitivity. This microscope can afford a lateral resolution of - 150 nm in liquid environment and - 200 nm in air. We present in this paper images of IMR90 fibroblasts obtained with SSPM in dried environment. Internal compartments such as nucleus, nucleolus, mitochondria, cellular and nuclear membrane can be recognized without labelling. We propose an interpretation of the ability of SSPM to reveal high index contrast zones by a local decomposition of the V (Z) function describing the response of the SSPM.

  4. Reprogramming of round spermatids by the germinal vesicle cytoplasm in mice.

    Directory of Open Access Journals (Sweden)

    Peng-Cheng Kong

    Full Text Available The birthrate following round spermatid injection (ROSI remains low in current and evidence suggests that factors in the germinal vesicle (GV cytoplasm and certain substances in the GV such as the nucleolus might be responsible for genomic reprogramming and embryonic development. However, little is known whether the reprogramming factors in GV oocyte cytoplasm and/or nucleolus in GV are beneficial to the reprogramming of round spermatids and development of ROSI embryos. Here, round spermatids were treated with GV cytolysates and injected this round spermatid alone or co-injected with GV oocyte nucleolus into mature metaphase II oocytes. Subsequent embryonic development was assessed morphologically and by Oct4 expression in blastocysts. There was no significant difference between experimental groups at the zygote to four-cell development stages. Blastocysts derived from oocytes which were injected with cytolysate treated-round spermatid alone or co-injected with nucleoli injection yielded 63.6% and 70.3% high quality embryos, respectively; comparable to blastocysts derived by intracytoplasmic sperm injection (ICSI, but higher than these oocytes which were co-injected with lysis buffer-treated round spermatids and nucleoli or injected with the lysis buffer-treated round spermatids alone. Furthermore, the proportion of live offspring resulting from oocytes which were co-injected with cytolysate treated-round spermatids and nucleoli or injected with cytolysate treated-round spermatids alone was higher than those were injected with lysis buffer treated-round spermaids, but comparable with the ICSI group. Our results demonstrate that factors from the GV cytoplasm improve round spermatid reprogramming, and while injection of the extra nucleolus does not obviously improve reprogramming its potential contribution, although which cannot be definitively excluded. Thus, some reprogramming factors are evidently present in GV oocyte cytoplasm and could

  5. Beta cell dynamics: beta cell replenishment, beta cell compensation and diabetes.

    Science.gov (United States)

    Cerf, Marlon E

    2013-10-01

    Type 2 diabetes, characterized by persistent hyperglycemia, arises mostly from beta cell dysfunction and insulin resistance and remains a highly complex metabolic disease due to various stages in its pathogenesis. Glucose homeostasis is primarily regulated by insulin secretion from the beta cells in response to prevailing glycemia. Beta cell populations are dynamic as they respond to fluctuating insulin demand. Beta cell replenishment and death primarily regulate beta cell populations. Beta cells, pancreatic cells, and extra-pancreatic cells represent the three tiers for replenishing beta cells. In rodents, beta cell self-replenishment appears to be the dominant source for new beta cells supported by pancreatic cells (non-beta islet cells, acinar cells, and duct cells) and extra-pancreatic cells (liver, neural, and stem/progenitor cells). In humans, beta cell neogenesis from non-beta cells appears to be the dominant source of beta cell replenishment as limited beta cell self-replenishment occurs particularly in adulthood. Metabolic states of increased insulin demand trigger increased insulin synthesis and secretion from beta cells. Beta cells, therefore, adapt to support their physiology. Maintaining physiological beta cell populations is a strategy for targeting metabolic states of persistently increased insulin demand as in diabetes.

  6. Rapid cooled lens cell

    Science.gov (United States)

    Stubbs, David M.; Hsu, Ike C.

    1991-12-01

    This paper describes the optomechanical design, thermal analysis, fabrication, and test evaluation processes followed in developing a rapid cooled, infrared lens cell. Thermal analysis was the key engineering discipline exercised in the design phase. The effect of thermal stress on the lens, induced by rapid cooling of the lens cell, was investigated. Features of this lens cell that minimized the thermal stress will be discussed in a dedicated section. The results of thermal analysis on the selected lens cell design and the selection of the flow channel design in the heat exchanger will be discussed. Throughout the paper engineering drawings, illustrations, analytical results, and photographs of actual hardware are presented.

  7. Cell sorting in development.

    Science.gov (United States)

    Krens, S F Gabby; Heisenberg, Carl-Philipp

    2011-01-01

    During the development of multicellular organisms, cell fate specification is followed by the sorting of different cell types into distinct domains from where the different tissues and organs are formed. Cell sorting involves both the segregation of a mixed population of cells with different fates and properties into distinct domains, and the active maintenance of their segregated state. Because of its biological importance and apparent resemblance to fluid segregation in physics, cell sorting was extensively studied by both biologists and physicists over the last decades. Different theories were developed that try to explain cell sorting on the basis of the physical properties of the constituent cells. However, only recently the molecular and cellular mechanisms that control the physical properties driving cell sorting, have begun to be unraveled. In this review, we will provide an overview of different cell-sorting processes in development and discuss how these processes can be explained by the different sorting theories, and how these theories in turn can be connected to the molecular and cellular mechanisms driving these processes.

  8. Red cell enzymes.

    Science.gov (United States)

    Paniker, N V

    1975-03-01

    As compared to other cells of the body, the mammalian red cell has one of the simplest structural organizations. As a result, this cell has been extensively used in studies involving the structure, function, and integrity of cell membranes as well as cytoplasmic events. Additionally, the metabolic activities of the red blood cell are also relatively simple. During the past quarter century or so, an ocean of knowledge has been gathered on various aspects of red cell metabolism and function. The fields of enzymes, hemoglobin, membrane, and metabolic products comprise the major portion of this knowledge. These advances have made valuable contributions to biochemistry and medicine. Despite these favorable aspects of this simple, anucleated cell, it must be conceded that our knowledge about the red cell is far from complete. We are still in the dark concerning the mechanism involved in several aspects of its membrane, hemoglobin, enzymes, and a large number of other constituents. For example, a large number of enzymes with known catalytic activity but with unknown function have eluded investigators despite active pursuit. This review will be a consolidation of our present knowledge of human red cell enzymes, with particular reference to their usefulness in the diagnosis and therapy of disease. Owing to the multitude of publications by prominent investigators on each of the approximately 50 enzymes discussed in this review, it was impossible to cite a majority of them.

  9. Littoral Cells 2005

    Data.gov (United States)

    California Department of Resources — Littoral cells along the California Coast. Originally digitized by Melanie Coyne from the Assessment and Atlas of Shoreline Erosion Along the California Coast...

  10. [Endothelial cell adhesion molecules].

    Science.gov (United States)

    Ivanov, A N; Norkin, I A; Puchin'ian, D M; Shirokov, V Iu; Zhdanova, O Iu

    2014-01-01

    The review presents current data concerning the functional role of endothelial cell adhesion molecules belonging to different structural families: integrins, selectins, cadherins, and the immunoglobulin super-family. In this manuscript the regulatory mechanisms and factors of adhesion molecules expression and distribution on the surface of endothelial cells are discussed. The data presented reveal the importance of adhesion molecules in the regulation of structural and functional state of endothelial cells in normal conditions and in pathology. Particular attention is paid to the importance of these molecules in the processes of physiological and pathological angiogenesis, regulation of permeability of the endothelial barrier and cell transmigration.

  11. Analysing immune cell migration.

    Science.gov (United States)

    Beltman, Joost B; Marée, Athanasius F M; de Boer, Rob J

    2009-11-01

    The visualization of the dynamic behaviour of and interactions between immune cells using time-lapse video microscopy has an important role in modern immunology. To draw robust conclusions, quantification of such cell migration is required. However, imaging experiments are associated with various artefacts that can affect the estimated positions of the immune cells under analysis, which form the basis of any subsequent analysis. Here, we describe potential artefacts that could affect the interpretation of data sets on immune cell migration. We propose how these errors can be recognized and corrected, and suggest ways to prevent the data analysis itself leading to biased results.

  12. Microencapsulation Of Living Cells

    Science.gov (United States)

    Chang, Manchium; Kendall, James M.; Wang, Taylor G.

    1989-01-01

    In experimental technique, living cells and other biological materials encapsulated within submillimeter-diameter liquid-filled spheres. Sphere material biocompatible, tough, and compliant. Semipermeable, permitting relatively small molecules to move into and out of sphere core but preventing passage of large molecules. New technique promises to make such spherical capsules at high rates and in uniform, controllable sizes. Capsules injected into patient through ordinary hypodermic needle. Promising application for technique in treatment of diabetes. Also used to encapsulate pituitary cells and thyroid hormone adrenocortical cells for treatment of other hormonal disorders, to encapsulate other secreting cells for transplantation, and to package variety of pharmaceutical products and agricultural chemicals for controlled release.

  13. Nanocrystal Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Gur, Ilan [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    This dissertation presents the results of a research agenda aimed at improving integration and stability in nanocrystal-based solar cells through advances in active materials and device architectures. The introduction of 3-dimensional nanocrystals illustrates the potential for improving transport and percolation in hybrid solar cells and enables novel fabrication methods for optimizing integration in these systems. Fabricating cells by sequential deposition allows for solution-based assembly of hybrid composites with controlled and well-characterized dispersion and electrode contact. Hyperbranched nanocrystals emerge as a nearly ideal building block for hybrid cells, allowing the controlled morphologies targeted by templated approaches to be achieved in an easily fabricated solution-cast device. In addition to offering practical benefits to device processing, these approaches offer fundamental insight into the operation of hybrid solar cells, shedding light on key phenomena such as the roles of electrode-contact and percolation behavior in these cells. Finally, all-inorganic nanocrystal solar cells are presented as a wholly new cell concept, illustrating that donor-acceptor charge transfer and directed carrier diffusion can be utilized in a system with no organic components, and that nanocrystals may act as building blocks for efficient, stable, and low-cost thin-film solar cells.

  14. Assessment of cell viability.

    Science.gov (United States)

    Johnson, Simon; Nguyen, Vy; Coder, David

    2013-01-01

    Cell viability may be judged by morphological changes or by changes in membrane permeability and/or physiological state inferred from the exclusion of certain dyes or the uptake and retention of others. This unit presents methods based on dye exclusion, esterase activity, and mitochondrial membrane potential, as well as protocols for determining the pre-fixation viability of fixed cells either before or after fixation with amine-reactive dyes suitable for a range of excitation wavelengths. Membrane-impermeable dead cell and live cell dyes as well as dye-exclusion procedures for microscopy are also included.

  15. Dedifferentiated adipocyte-derived progeny cells (DFAT cells)

    OpenAIRE

    Wei, Shengjuan; Zan, Linsen; Hausman, Gary J.; Rasmussen, Theodore P; Bergen, Werner G.; Dodson, Michael V.

    2013-01-01

    Analyses of mature adipocytes have shown that they possess a reprogramming ability in vitro, which is associated with dedifferentiation. The subsequent dedifferentiated fat cells (DFAT cells) are multipotent and can differentiate into adipocytes and other cell types as well. Mature adipocytes can be easily obtained by biopsy, and the cloned progeny cells are homogeneous in vitro. Therefore, DFAT cells (a new type of stem cell) may provide an excellent source of cells for tissue regeneration, ...

  16. A focus on parietal cells as a renewing cell population

    Institute of Scientific and Technical Information of China (English)

    Sherif; M; Karam

    2010-01-01

    The fact that the acidsecreting parietal cells undergo continuous renewal has been ignored by many gastroenterologists and cell biologists. In the past, it was thought that these cells were static. However, by using 3Hthymidine radioautography in combination with electron microscopy, it was possible to demonstrate that parietal cells belong to a continuously renewing epithelial cell lineage. In the gastric glands, stem cells anchored in the isthmus region are responsible for the production of parietal cells...

  17. Regulation of B Cell to Plasma Cell Transition within the Follicular B Cell Response.

    Science.gov (United States)

    Nera, K-P; Kyläniemi, M K; Lassila, O

    2015-09-01

    Persistent humoral immunity depends on the follicular B cell response and on the generation of somatically mutated high-affinity plasma cells and memory B cells. Upon activation by an antigen, cognately activated follicular B cells and follicular T helper (TFH ) cells initiate germinal centre (GC) reaction during which high-affinity effector cells are generated. The differentiation of activated follicular B cells into plasma cells and memory B cells is guided by complex selection events, both at the cellular and molecular level. The transition of B cell into a plasma cell during the GC response involves alterations in the microenvironment and developmental state of the cell, which are guided by cell-extrinsic signals. The developmental cell fate decisions in response to these signals are coordinated by cell-intrinsic gene regulatory network functioning at epigenetic, transcriptional and post-transcriptional levels.

  18. Regulation of the Bfa1p-Bub2p complex at spindle pole bodies by the cell cycle phosphatase Cdc14p.

    Science.gov (United States)

    Pereira, Gislene; Manson, Claire; Grindlay, Joan; Schiebel, Elmar

    2002-04-29

    The budding yeast mitotic exit network (MEN) is a GTPase-driven signal transduction cascade that controls the release of the phosphatase Cdc14p from the nucleolus in anaphase and thereby drives mitotic exit. We show that Cdc14p is partially released from the nucleolus in early anaphase independent of the action of the MEN components Cdc15p, Dbf2p, and Tem1p. Upon release, Cdc14p binds to the spindle pole body (SPB) via association with the Bfa1p-Bub2p GTPase activating protein complex, which is known to regulate the activity of the G protein Tem1p. Cdc14p also interacts with this GTPase. The association of the MEN component Mob1p with the SPB acts as a marker of MEN activation. The simultaneous binding of Cdc14p and Mob1p to the SPB in early anaphase suggests that Cdc14p initially activates the MEN. In a second, later step, which coincides with mitotic exit, Cdc14p reactivates the Bfa1p-Bub2p complex by dephosphorylating Bfa1p. This inactivates the MEN and displaces Mob1p from SPBs. These data indicate that Cdc14p activates the MEN in early anaphase but later inactivates it through Bfa1p dephosphorylation and so restricts MEN activity to a short period in anaphase.

  19. Regulation of beta cell replication

    DEFF Research Database (Denmark)

    Lee, Ying C; Nielsen, Jens Høiriis

    2008-01-01

    Beta cell mass, at any given time, is governed by cell differentiation, neogenesis, increased or decreased cell size (cell hypertrophy or atrophy), cell death (apoptosis), and beta cell proliferation. Nutrients, hormones and growth factors coupled with their signalling intermediates have been...... suggested to play a role in beta cell mass regulation. In addition, genetic mouse model studies have indicated that cyclins and cyclin-dependent kinases that determine cell cycle progression are involved in beta cell replication, and more recently, menin in association with cyclin-dependent kinase...... inhibitors has been demonstrated to be important in beta cell growth. In this review, we consider and highlight some aspects of cell cycle regulation in relation to beta cell replication. The role of cell cycle regulation in beta cell replication is mostly from studies in rodent models, but whether...

  20. Dramatically improved RNA in situ hybridization signals using LNA-modified probes

    DEFF Research Database (Denmark)

    Thomsen, Rune; Nielsen, Peter Stein; Jensen, Torben Heick

    2005-01-01

    In situ detection of RNA by hybridization with complementary probes is a powerful technique. Probe design is a critical parameter in successful target detection. We have evaluated the efficiency of fluorescent DNA oligonucleotides modified to contain locked nucleic acid (LNA) residues. This incre...... the nucleus/ nucleolus of wild-type cells. LNA-based probes should be readily applicable to a diverse array of cells and tissue samples....

  1. Single-cell sequencing in stem cell biology.

    Science.gov (United States)

    Wen, Lu; Tang, Fuchou

    2016-04-15

    Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of stem cell populations, but these differences are masked when bulk cells are used for omic analysis. Single-cell sequencing technologies serve as powerful tools to dissect cellular heterogeneity comprehensively and to identify distinct phenotypic cell types, even within a 'homogeneous' stem cell population. These technologies, including single-cell genome, epigenome, and transcriptome sequencing technologies, have been developing rapidly in recent years. The application of these methods to different types of stem cells, including pluripotent stem cells and tissue-specific stem cells, has led to exciting new findings in the stem cell field. In this review, we discuss the recent progress as well as future perspectives in the methodologies and applications of single-cell omic sequencing technologies.

  2. Wnt-Dependent Control of Cell Polarity in Cultured Cells.

    Science.gov (United States)

    Runkle, Kristin B; Witze, Eric S

    2016-01-01

    The secreted ligand Wnt5a regulates cell polarity and polarized cell movement during development by signaling through the poorly defined noncanonical Wnt pathway. Cell polarity regulates most aspects of cell behavior including the organization of apical/basolateral membrane domains of epithelial cells, polarized cell divisions along a directional plane, and front rear polarity during cell migration. These characteristics of cell polarity allow coordinated cell movements required for tissue formation and organogenesis during embryonic development. Genetic model organisms have been used to identify multiple signaling pathways including Wnt5a that are required to establish cell polarity and regulate polarized cell behavior. However, the downstream signaling events that regulate these complex cellular processes are still poorly understood. The methods below describe assays to study Wnt5a-induced cell polarity in cultured cells, which may facilitate our understanding of these complex signaling pathways.

  3. Molecular mechanisms controlling the cell cycle in embryonic stem cells.

    Science.gov (United States)

    Abdelalim, Essam M

    2013-12-01

    Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal.

  4. Enrichment of Fetal Nucleated Red Blood Cell in Peripheral Blood of Pregnant Woman by Joint Use of Density Gradient Centrifugation and Keihuaer Acid-fast Staining%密度梯度离心结合Keihuaer抗酸染色法富集孕妇外周血中FNRBC的研究

    Institute of Scientific and Technical Information of China (English)

    何国平; 刘雨生; 童先宏; 郑圣霞; 张荣; 王念念; 吴丽敏; 周桂香

    2009-01-01

    Objective To investigate and establish a simple, rapid and lower-cost method to enrich fetal nucleated red blood cell(FNRBC) in peripheral blood of pregnant woman. Methods About 10 ml of peripheral blood sample from 18 pregnant women with gestational weeks arranged from 8 to 16 was collected, and then subjected to the discontinuous density gradient centrifugation. After the primary cell isolation, Keihuaer acid-fast staining method was used to mark the isolated cells previously spread on the slides. The special morphocytology and colour staining of FNRBC could be distinctly distinguished from the surrounding mother cells. Following that, the special antibody against fetal hemoglobin was further used to validate the fetus-originated characteristics for the positive FNRBC staining slides.Results After dealing with Keihuaer acid-fast staining, the cytoplasm of positive FNRBC was stained to be scarlet,nucleolus to be blue,while the cytoplasm of mother cells were colorless. The positive FNRBC were detected in 14 of 18 healthy pregnant women, average 1 to 6 cells per case,the positive rate was 77.8%. The same experimental results was further validated with the special antibody against fetal hemoglobin immunocytochemical staining,the diagnose accordance rate was 100.0%. Conclusions The density gradient centrifugation,together with Keihuaer acid-fast staining were highly special for the enrichment of FNRBC in peripheral blood of pregnant woman. The practical operation of this method was simple,fast and the future investigations would hopefully prove its worth in the clinical application of noninvasive prenatal diagnosis of gene disorders.%目的 探索建立一种简便、快速、较低成本的用于孕妇外周血胎儿有核红细胞(FNRBC)富集的实验方法.方法 采集18名孕周在8~16周的孕妇外周血10 ml,经Percoll不连续密度梯度离心初步分离后,运用Keihuaer抗酸染色法对玻片上的细胞进行染色标记,显微镜下观察、辨

  5. Small cell glioblastoma or small cell carcinoma

    DEFF Research Database (Denmark)

    Hilbrandt, Christine; Sathyadas, Sathya; Dahlrot, Rikke H

    2013-01-01

    was admitted to the hospital with left-sided loss of motor function. A MRI revealed a 6 cm tumor in the right temporoparietal area. The histology was consistent with both glioblastoma multiforme (GBM) and small cell lung carcinoma (SCLC) but IHC was suggestive of a SCLC metastasis. PET-CT revealed...

  6. The marrow haemopoietic stem cells mobilization affecting the retinal neovascularization induced by laser%骨髓干细胞动员对激光诱导视网膜新生血管产生的影响

    Institute of Scientific and Technical Information of China (English)

    赖铭莹; 应方微

    2010-01-01

    目的 了解高能激光诱导兔实验性新生血管过程中给予骨髓动员对新生血管形成的影响.方法 取高能激光光凝10只有色家兔(20只眼)视网膜后7d,6只兔给予连续皮下注射GMFS共5d进行骨髓动员,并以Brdu标记外周血的单个核细胞,在动员前,动员后1周、2周及3周分别取激光光凝斑处的球壁进行常规HE染色,并行免疫组化检测局部Brdu分布,对照组光凝后21d取光凝斑处的球壁做为对照.结果 骨髓动员兔的视网膜激光光凝斑处视网膜新生血管少见,主要为纤维性修复,纤维瘢痕收缩;对照组激光诱导视网膜形成明显的新生血管.免疫组化显示激光动员兔激光斑处可见Brdu阳性的细胞,对照组则为阴性.结论 骨髓动员能够抑制高能激光诱导的兔视网膜新生血管形成,促进纤维组织生长,动员的细胞可能直接参与了纤维修复.%Objective To understand the effect of the marrow haemopoietic stem cells mobilization during the rabbits' retinal neovascularization induced by laser.Methods Seven days after 10 color rabbits (20 eyes) received high-energy Argon laser to induce the retinal neovascularization, 6 of them injected subcutaneous with GMFS for 5 days continuously, then the single nucleolus cells in the blood were marked with Brdu, and last, the retina of the laser light spots before and 1 to 3 weeks after marrow mobilization were obtained to stain with HE and observe the disposition of Brdu by the immunohistochemistry, the other 4 rabbits' retina were treated as the contrast 21 days after laser light exposure.Results The retina new vessels were less, fibrous repaired and scar formed in morrow mobilization group than that of the contrast, and the Brdu was positive, while the contrast was negative.Conclusions The marrow mobilization can reduce the retinal neovascularization induced by laser, and develop fibrous tissue growing, perhaps the cells of mobilization joined in the fibrous repair

  7. Dedifferentiated adipocyte-derived progeny cells (DFAT cells): Potential stem cells of adipose tissue.

    Science.gov (United States)

    Wei, Shengjuan; Zan, Linsen; Hausman, Gary J; Rasmussen, Theodore P; Bergen, Werner G; Dodson, Michael V

    2013-07-01

    Analyses of mature adipocytes have shown that they possess a reprogramming ability in vitro, which is associated with dedifferentiation. The subsequent dedifferentiated fat cells (DFAT cells) are multipotent and can differentiate into adipocytes and other cell types as well. Mature adipocytes can be easily obtained by biopsy, and the cloned progeny cells are homogeneous in vitro. Therefore, DFAT cells (a new type of stem cell) may provide an excellent source of cells for tissue regeneration, engineering and disease treatment. The dedifferentiation of mature adipocytes, the multipotent capacity of DFAT cells and comparisons and contrasts with mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPS) are discussed in this review.

  8. Biosensors for Cell Analysis.

    Science.gov (United States)

    Zhou, Qing; Son, Kyungjin; Liu, Ying; Revzin, Alexander

    2015-01-01

    Biosensors first appeared several decades ago to address the need for monitoring physiological parameters such as oxygen or glucose in biological fluids such as blood. More recently, a new wave of biosensors has emerged in order to provide more nuanced and granular information about the composition and function of living cells. Such biosensors exist at the confluence of technology and medicine and often strive to connect cell phenotype or function to physiological or pathophysiological processes. Our review aims to describe some of the key technological aspects of biosensors being developed for cell analysis. The technological aspects covered in our review include biorecognition elements used for biosensor construction, methods for integrating cells with biosensors, approaches to single-cell analysis, and the use of nanostructured biosensors for cell analysis. Our hope is that the spectrum of possibilities for cell analysis described in this review may pique the interest of biomedical scientists and engineers and may spur new collaborations in the area of using biosensors for cell analysis.

  9. MICROBIAL FUEL CELL

    DEFF Research Database (Denmark)

    2008-01-01

    A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

  10. Ghost cell odontogenic carcinoma.

    NARCIS (Netherlands)

    Nazaretian, S.P.; Schenberg, M.E.; Simpson, I.; Slootweg, P.J.

    2007-01-01

    Ghost cell odontogenic carcinoma (GCOC) is the malignant counterpart of calcifying cystic odontogenic tumour and dentinogenic ghost cell tumour. This is the case of a middle-aged male who presented with a slow-growing maxillary tumour. He was asymptomatic until pain symptoms developed prior to initi

  11. Electrochemical cell stack assembly

    Science.gov (United States)

    Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2010-06-22

    Multiple stacks of tubular electrochemical cells having a dense electrolyte disposed between an anode and a cathode preferably deposited as thin films arranged in parallel on stamped conductive interconnect sheets or ferrules. The stack allows one or more electrochemical cell to malfunction without disabling the entire stack. Stack efficiency is enhanced through simplified gas manifolding, gas recycling, reduced operating temperature and improved heat distribution.

  12. Ghrelin and cell differentiation

    Institute of Scientific and Technical Information of China (English)

    Geyang Xu; Yin Li; Wenjiao An; Weizhen Zhang

    2008-01-01

    Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is a gastric hormone that has been found to have a wide variety of biological functions. This review summarizes our current understanding of the effects of ghrelin on cell differentiation and tissue development, with an emphasis on the lineage determination of mesenchymal stem cells.

  13. Cell Phones for Education

    Science.gov (United States)

    Roberson, James H.; Hagevik, Rita A.

    2008-01-01

    Cell phones are fast becoming an integral part of students' everyday lives. They are regarded as important companions and tools for personal expression. School-age children are integrating the cell phone as such, and thus placing a high value on them. Educators endeavor to instill in students a high value for education, but often meet with…

  14. PLATINUM AND FUEL CELLS

    Science.gov (United States)

    Platinum requirements for fuel cell vehicles (FCVS) have been identified as a concern and possible problem with FCV market penetration. Platinum is a necessary component of the electrodes of fuel cell engines that power the vehicles. The platinum is deposited on porous electrodes...

  15. Modeling: driving fuel cells

    Directory of Open Access Journals (Sweden)

    Michael Francis

    2002-05-01

    Fuel cells were invented in 1839 by Sir William Grove, a Welsh judge and gentleman scientist, as a result of his experiments on the electrolysis of water. To put it simply, fuel cells are electrochemical devices that take hydrogen gas from fuel, combine it with oxygen from the air, and generate electricity and heat, with water as the only by-product.

  16. The Constitution by Cell

    Science.gov (United States)

    Greenhut, Stephanie; Jones, Megan

    2010-01-01

    On their visit to the National Archives Experience in Washington, D.C., students in Jenni Ashley and Gay Brock's U.S. history classes at the Potomac School in McLean, Virginia, participated in a pilot program called "The Constitution by Cell." Armed with their cell phones, a basic understanding of the Constitution, and a willingness to participate…

  17. Programmed cell death

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The purpose of this conference to provide a multidisciplinary forum for exchange of state-of-the-art information on the role programmed cell death plays in normal development and homeostasis of many organisms. This volume contains abstracts of papers in the following areas: invertebrate development; immunology/neurology; bcl-2 family; biochemistry; programmed cell death in viruses; oncogenesis; vertebrate development; and diseases.

  18. Fuel cells: Operating flexibly

    Science.gov (United States)

    Lee, Young Moo

    2016-09-01

    Fuel cells typically function well only in rather limited temperature and humidity ranges. Now, a proton exchange membrane consisting of ion pair complexes is shown to enable improved fuel cell performance under a wide range of conditions that are unattainable with conventional approaches.

  19. Tetraspanins in Mast Cells

    Directory of Open Access Journals (Sweden)

    Martin eKöberle

    2012-05-01

    Full Text Available Mast cells are key mediators of the immune system, most prominently known for their role in eliciting harmful allergic reactions. Mast cell mediator release (e. g. by degranulation is triggered by Fc{epsilon}RI recognition of antigen – IgE complexes. Until today no therapeutic targeting of this and other mast cell activation pathways is established. Among possible new candidates there are tetraspanins that have been described on mast cells already several years ago.Tetraspanins are transmembrane proteins acting as scaffolds, mediating local clustering of their interaction partners and thus amplify their activities. More recently, tetraspanins were also found to exert intrinsic receptor functions. Tetraspanins have been found to be crucial components of fundamental biological processes like cell motility and adhesion. In immune cells, they not only boost the effectiveness of antigen presentation by clustering MHC molecules, they are also key players in all kinds of degranulation events and immune receptor clustering. This review focuses on the contribution of tetraspanins clustered with Fc{epsilon}RI or residing in granule membranes to classical mast cells functions but also undertakes an outlook on the possible contribution of tetraspanins to newly described mast cell functions and discusses possible drugging strategies.

  20. Tumor cell metabolism

    Science.gov (United States)

    Romero-Garcia, Susana; Lopez-Gonzalez, Jose Sullivan; B´ez-Viveros, José Luis; Aguilar-Cazares, Dolores

    2011-01-01

    Cancer is a genetic disease that is caused by mutations in oncogenes, tumor suppressor genes and stability genes. The fact that the metabolism of tumor cells is altered has been known for many years. However, the mechanisms and consequences of metabolic reprogramming have just begun to be understood. In this review, an integral view of tumor cell metabolism is presented, showing how metabolic pathways are reprogrammed to satisfy tumor cell proliferation and survival requirements. In tumor cells, glycolysis is strongly enhanced to fulfill the high ATP demands of these cells; glucose carbons are the main building blocks in fatty acid and nucleotide biosynthesis. Glutaminolysis is also increased to satisfy NADPH regeneration, whereas glutamine carbons replenish the Krebs cycle, which produces metabolites that are constantly used for macromolecular biosynthesis. A characteristic feature of the tumor microenvironment is acidosis, which results from the local increase in lactic acid production by tumor cells. This phenomenon is attributed to the carbons from glutamine and glucose, which are also used for lactic acid production. Lactic acidosis also directs the metabolic reprogramming of tumor cells and serves as an additional selective pressure. Finally, we also discuss the role of mitochondria in supporting tumor cell metabolism. PMID:22057267