WorldWideScience

Sample records for cell cycle stage

  1. Sorting of cells of the same size, shape, and cell cycle stage for a single cell level assay without staining

    Directory of Open Access Journals (Sweden)

    Yomo Tetsuya

    2006-06-01

    Full Text Available Abstract Background Single-cell level studies are being used increasingly to measure cell properties not directly observable in a cell population. High-performance data acquisition systems for such studies have, by necessity, developed in synchrony. However, improvements in sample purification techniques are also required to reveal new phenomena. Here we assessed a cell sorter as a sample-pretreatment tool for a single-cell level assay. A cell sorter is routinely used for selecting one type of cells from a heterogeneous mixture of cells using specific fluorescence labels. In this case, we wanted to select cells of exactly the same size, shape, and cell-cycle stage from a population, without using a specific fluorescence label. Results We used four light scatter parameters: the peak height and area of the forward scatter (FSheight and FSarea and side scatter (SSheight and SSarea. The rat pheochromocytoma PC12 cell line, a neuronal cell line, was used for all experiments. The living cells concentrated in the high FSarea and middle SSheight/SSarea fractions. Single cells without cell clumps were concentrated in the low SS and middle FS fractions, and in the higher FSheight/FSarea and SSheight/SSarea fractions. The cell populations from these viable, single-cell-rich fractions were divided into twelve subfractions based on their FSarea-SSarea profiles, for more detailed analysis. We found that SSarea was proportional to the cell volume and the FSarea correlated with cell roundness and elongation, as well as with the level of DNA in the cell. To test the method and to characterize the basic properties of the isolated single cells, sorted cells were cultured in separate wells. The cells in all subfractions survived, proliferated and differentiated normally, suggesting that there was no serious damage. The smallest, roundest, and smoothest cells had the highest viability. There was no correlation between proliferation and differentiation. NGF increases

  2. In vitro alterations do not reflect a requirement for host cell cycle progression during Plasmodium liver stage infection.

    Science.gov (United States)

    Hanson, Kirsten K; March, Sandra; Ng, Shengyong; Bhatia, Sangeeta N; Mota, Maria M

    2015-01-01

    Prior to invading nonreplicative erythrocytes, Plasmodium parasites undergo their first obligate step in the mammalian host inside hepatocytes, where each sporozoite replicates to generate thousands of merozoites. While normally quiescent, hepatocytes retain proliferative capacity and can readily reenter the cell cycle in response to diverse stimuli. Many intracellular pathogens, including protozoan parasites, manipulate the cell cycle progression of their host cells for their own benefit, but it is not known whether the hepatocyte cell cycle plays a role during Plasmodium liver stage infection. Here, we show that Plasmodium parasites can be observed in mitotic hepatoma cells throughout liver stage development, where they initially reduce the likelihood of mitosis and ultimately lead to significant acquisition of a binucleate phenotype. However, hepatoma cells pharmacologically arrested in S phase still support robust and complete Plasmodium liver stage development, which thus does not require cell cycle progression in the infected cell in vitro. Furthermore, murine hepatocytes remain quiescent throughout in vivo infection with either Plasmodium berghei or Plasmodium yoelii, as do Plasmodium falciparum-infected primary human hepatocytes, demonstrating that the rapid and prodigious growth of liver stage parasites is accomplished independent of host hepatocyte cell cycle progression during natural infection.

  3. Weak bases affect late stages of Mayaro virus replication cycle in vertebrate cells.

    Science.gov (United States)

    Ferreira, D F; Santo, M P; Rebello, M A; Rebello, M C

    2000-04-01

    This paper describes the effect of two weak bases (ammonium chloride and chloroquine) on the morphogenesis of Mayaro virus. When Mayaro virus-infected TC7 (monkey kidney) cells were treated with these agents it was observed that weak bases caused a significant reduction in virus yield. Also, cellular protein synthesis, which is inhibited by Mayaro virus infection, recovered to nearly normal levels. However, the synthesis of Mayaro virus proteins was affected. These phenomena were dose-dependent. The process of Mayaro virus infection in vertebrate cells is very rapid. Virus precursors are not observed in cell cytoplasm and budding through the plasma membrane seems to be the only way of virus release. Electron microscopy of cells infected with Mayaro virus and treated with weak bases revealed an accumulation of virus structures in cell cytoplasm. The study also noted an inhibition of budding through the plasma membrane and the appearance of virus particles inside intracytoplasmic vacuoles. These observations indicate an impairment at the final stages of the virus replication cycle.

  4. Measuring the DNA Content of Cells in Apoptosis and at Different Cell-Cycle Stages by Propidium Iodide Staining and Flow Cytometry.

    Science.gov (United States)

    Crowley, Lisa C; Chojnowski, Grace; Waterhouse, Nigel J

    2016-10-03

    All cells are created from preexisting cells. This involves complete duplication of the parent cell to create two daughter cells by a process known as the cell cycle. For this process to be successful, the DNA of the parent cell must be faithfully replicated so that each daughter cell receives a full copy of the genetic information. During the cell cycle, the DNA content of the parent cell increases as new DNA is synthesized (S phase). When there are two full copies of the DNA (G2/M phase), the cell splits to form two new cells (G0/G1 phase). As such, cells in different stages of the cell cycle have different DNA contents. The cell cycle is tightly regulated to safeguard the integrity of the cell and any cell that is defective or unable to complete the cell cycle is programmed to die by apoptosis. When this occurs, the DNA is fragmented into oligonucleosomal-sized fragments that are disposed of when the dead cell is removed by phagocytosis. Consequently apoptotic cells have reduced DNA content compared with living cells. This can be measured by staining cells with propidium iodide (PI), a fluorescent molecule that intercalates with DNA at a specific ratio. The level of PI fluorescence in a cell is, therefore, directly proportional to the DNA content of that cell. This protocol describes the use of PI staining to determine the percentage of cells in each phase of the cell cycle and the percentage of apoptotic cells in a sample.

  5. Immunohistochemical study of the expression of cell cycle regulating proteins at different stages of bladder cancer

    DEFF Research Database (Denmark)

    Primdahl, Hanne; Maase, Hans von der; Sørensen, Flemming B.

    2002-01-01

    PURPOSE: The cell cycle is known to be deregulated in cancer. We therefore analyzed the expression of the cell cycle related proteins p21, p27, p16, Rb, and L-myc by immunohistochemical staining of bladder tumors. METHODS: The tissue material consisted of bladder tumors from three groups......(kip1) ( P=0.03), Rb ( P=0.00002), and L-myc ( P=0.00000007) in muscle invasive tumors compared to noninvasive tumors. Tumors presenting as muscle invasive at first diagnosis had significantly lower levels of p16/CDKN2A ( P=0.01) when compared to muscle invasive tumors that followed Ta or T1 precursor...

  6. Azathioprine inhibits vaccinia virus replication in both BSC-40 and RAG cell lines acting on different stages of virus cycle.

    Science.gov (United States)

    Damaso, Clarissa R A; Oliveira, Marcus F; Massarani, Susana M; Moussatché, Nissin

    2002-08-15

    In the present study we demonstrate that azathioprine (AZA) inhibits vaccinia virus (VV) replication in both BSC-40 and RAG cell lines, acting on different stages of virus cycle. In BSC-40 cells, early protein synthesis was not significantly affected, but late gene expression was severely impaired. In RAG cells all stages of gene expression were completed during synchronous infection in the presence of the drug. The onset of DNA replication was not affected in RAG cells, but a severe inhibition was observed in BSC-40 cells. Electron microscopic analysis of VV-infected RAG cells treated with AZA revealed brick-shaped particles presenting abnormal definition of the internal structure. Purified virions from AZA-treated RAG cells presented several modifications of the protein content, a lesser amount of DNA, and a lower PFU:particle ratio. Our results suggest that in VV-infected RAG cells AZA interfered with virus morphogenesis, whereas in BSC-40 cells the replicative cycle was inhibited at the DNA replication stage.

  7. Murine Wee1 Plays a Critical Role in Cell Cycle Regulation and Pre-Implantation Stages of Embryonic Development

    Directory of Open Access Journals (Sweden)

    Yohei Tominaga, Cuiling Li, Rui-Hong Wang, Chu-Xia Deng

    2006-01-01

    Full Text Available Wee1 kinase regulates the G2/M cell cycle checkpoint by phosphorylating and inactivating the mitotic cyclin-dependent kinase 1 (Cdk1. Loss of Wee1 in many systems, including yeast and drosophila, leads to premature mitotic entry. However, the developmental role of Wee1 in mammals remains unclear. In this study, we established Wee1 knockout mice by gene targeting. We found that Wee-/- embryos were defective in the G2/M cell cycle checkpoint induced by γ-irradiation and died of apoptosis before embryonic (E day 3.5. To study the function of Wee1 further, we have developed MEF cells in which Wee1 is disrupted by a tamoxifen inducible Cre-LoxP approach. We found that acute deletion of Wee1 resulted in profound growth defects and cell death. Wee1 deficient cells displayed chromosome aneuploidy and DNA damage as revealed by γ-H2AX foci formation and Chk2 activation. Further studies revealed a conserved mechanism of Wee1 in regulating mitotic entry and the G2/M checkpoint compared with other lower organisms. These data provide in vivo evidence that mammalian Wee1 plays a critical role in maintaining genome integrity and is essential for embryonic survival at the pre-implantation stage of mouse development.

  8. An atlas for Schistosoma mansoni organs and life-cycle stages using cell type-specific markers and confocal microscopy.

    Directory of Open Access Journals (Sweden)

    James J Collins

    Full Text Available Schistosomiasis (bilharzia is a tropical disease caused by trematode parasites (Schistosoma that affects hundreds of millions of people in the developing world. Currently only a single drug (praziquantel is available to treat this disease, highlighting the importance of developing new techniques to study Schistosoma. While molecular advances, including RNA interference and the availability of complete genome sequences for two Schistosoma species, will help to revolutionize studies of these animals, an array of tools for visualizing the consequences of experimental perturbations on tissue integrity and development needs to be made widely available. To this end, we screened a battery of commercially available stains, antibodies and fluorescently labeled lectins, many of which have not been described previously for analyzing schistosomes, for their ability to label various cell and tissue types in the cercarial stage of S. mansoni. This analysis uncovered more than 20 new markers that label most cercarial tissues, including the tegument, the musculature, the protonephridia, the secretory system and the nervous system. Using these markers we present a high-resolution visual depiction of cercarial anatomy. Examining the effectiveness of a subset of these markers in S. mansoni adults and miracidia, we demonstrate the value of these tools for labeling tissues in a variety of life-cycle stages. The methodologies described here will facilitate functional analyses aimed at understanding fundamental biological processes in these parasites.

  9. Measurement of X-ray-induced DNA double-strand breaks at various stages of the cell cycle using the total fluorescence as a comet assay parameter

    Energy Technology Data Exchange (ETDEWEB)

    Attia, Atef M.M. [Department of Biochemistry, Biophysical laboratory, National Research Center, Dokki, Cairo (Egypt); Nabil, Ghada M., E-mail: gmnabilnooh@hotmail.com [Department of Biochemistry, Biophysical laboratory, National Research Center, Dokki, Cairo (Egypt); Frankenberg, Dieter; Frankenberg-Schwager, M. [Abteilung Klinische Strahlenbiologie und Klinische Strahlenphysik, Zentrum, Radiologie, Georg-August-Universitaet Goettingen, Von-Siebold-Str.3 (Germany)

    2011-11-15

    The aim of the study was to develop a protocol for both estimating cell cycle position and the level of ionizing radiation-induced DNA dsb using the neutral comet assay. Using DNA histograms, cell cycle positions were determined for human dermal fibroblasts. The tail intensity was used to estimate the level of DNA damage induced by X-rays, at different positions of the cell cycle. The results of tail intensity versus DNA content bivariate analysis of exponentially growing cells showed a remarkable decrease in tail intensity with transition of cells from G1 to S-phase and increases slightly with transition to G2/M phase. This effect is observed at all doses including unirradiated cells, indicating that the effect is not caused by X-rays and the comet assay based on the current tail parameters is not relevant to measure DNA damage at various stages of the cell cycle. The results of dose response curves showed a linear decrease in the comet fluorescence with the X-ray dose. This observation provides a basis for estimating the fraction of damaged DNA, based on the fluorescence decrement induced by ionizing radiation. The results of this new approach showed a linear increase in DNA damage with dose, at various stages of the cell cycle, with rates, which vary in the following order G0>G2/M>S/G1 cells. These results suggest that G0 and G2/M cells are the most sensitive to X-rays among all phases of the cell cycle and suggest synchronization of cells at these phases to increase the cellular radiosensitivity during radiotherapy. - Display Omitted Highlights: > Increase in DNA damage with dose. > Introduction of a new technique for measuring DNA damage using a new approach of the neutral comet assay. > Estimation of DNA damage in mammalian cells.

  10. Measurement of X-ray-induced DNA double-strand breaks at various stages of the cell cycle using the total fluorescence as a comet assay parameter

    Science.gov (United States)

    Attia, Atef M. M.; Nabil, Ghada M.; Frankenberg, Dieter; Frankenberg-Schwager, M.

    2011-11-01

    The aim of the study was to develop a protocol for both estimating cell cycle position and the level of ionizing radiation-induced DNA dsb using the neutral comet assay. Using DNA histograms, cell cycle positions were determined for human dermal fibroblasts. The tail intensity was used to estimate the level of DNA damage induced by X-rays, at different positions of the cell cycle. The results of tail intensity versus DNA content bivariate analysis of exponentially growing cells showed a remarkable decrease in tail intensity with transition of cells from G1 to S-phase and increases slightly with transition to G2/M phase. This effect is observed at all doses including unirradiated cells, indicating that the effect is not caused by X-rays and the comet assay based on the current tail parameters is not relevant to measure DNA damage at various stages of the cell cycle. The results of dose response curves showed a linear decrease in the comet fluorescence with the X-ray dose. This observation provides a basis for estimating the fraction of damaged DNA, based on the fluorescence decrement induced by ionizing radiation. The results of this new approach showed a linear increase in DNA damage with dose, at various stages of the cell cycle, with rates, which vary in the following order G0>G2/M>S/G1 cells.These results suggest that G0 and G2/M cells are the most sensitive to X-rays among all phases of the cell cycle and suggest synchronization of cells at these phases to increase the cellular radiosensitivity during radiotherapy.

  11. Differential expression of Yes-associated protein is correlated with expression of cell cycle markers and pathologic TNM staging in non-small-cell lung carcinoma.

    Science.gov (United States)

    Kim, Jin Man; Kang, Dong Wook; Long, Liang Zhe; Huang, Song-Mei; Yeo, Min-Kyung; Yi, Eunhee S; Kim, Kyung-Hee

    2011-03-01

    Yes-associated protein, a downstream effector of the Hippo signaling pathway, has been linked to progression of non-small-cell lung carcinoma. The aim of this study was to investigate expression of Yes-associated protein in lung adenocarcinoma and squamous cell carcinoma. Associations of Yes-associated protein expression with clinicopathologic parameters, expression of cell cycle-specific markers, and epidermal growth factor receptor gene amplification were also analyzed. In a univariate analysis of the 66 adenocarcinomas, high nuclear expression of Yes-associated protein was significantly correlated with expression of cyclin A and mitogen-activated protein kinase. Multivariate analysis, including age and sex, showed that cyclin A expression was independently correlated with nuclear expression of Yes-associated protein in adenocarcinomas. Furthermore, high nuclear expression of Yes-associated protein was also a significant predictor of epidermal growth factor receptor gene amplification for adenocarcinoma. For the 102 squamous cell carcinomas, univariate analysis revealed that high cytoplasmic expression of Yes-associated protein was correlated with the low pathologic TNM staging (stage I) and histologic grading. Multivariate analysis, including age and sex, showed that cytoplasmic expression of Yes-associated protein was an independent predictor of low pathologic TNM staging. These results indicate that nuclear overexpression of Yes-associated protein contributes to pulmonary adenocarcinoma growth and that high cytoplasmic expression of Yes-associated protein is an independent predictor of low pathologic TNM staging and histologic grading. The differential effects of Yes-associated protein expression patterns in adenocarcinomas and squamous cell carcinomas suggest that Yes-associated protein may play important roles in different pathways in distinct tumor subtypes. These observations may, therefore, lead to new perspectives on therapeutic targeting of these tumor

  12. Circadian variations of clock gene Per2 and cell cycle genes in different stages of carcinogenesis in golden hamster buccal mucosa.

    Science.gov (United States)

    Tan, Xue-Mei; Ye, Hua; Yang, Kai; Chen, Dan; Wang, Qing-Qing; Tang, Hong; Zhao, Ning-Bo

    2015-05-07

    Previous studies have suggested that the expression of clock genes have circadian rhythms, and many cell cycle genes are regulated by clock genes. The disruption of circadian rhythms appears to be associated with the acceleration of cancer development. To investigate the circadian patterns of the clock gene Per2 and of cell cycle genes p53, Cyclin D1, CDK1 and Cyclin B1 in different stages of carcinogenesis, the daily mRNA profiles of these genes were detected by real-time RT-PCR in dimethylbenzanthracene-induced cancer, in precancerous lesions and in normal tissues. Per2, p53, Cyclin D1 and CDK1 showed circadian rhythms in the 3 different stages of carcinogenesis, whereas the circadian rhythm of Cyclin B1 was absent in the precancerous lesions. The mesors and amplitudes of Per2 and p53 were decreased (P circadian pattern variations of these genes in different stages of carcinogenesis.

  13. Frailty of two cell cycle checkpoints which prevent entry into mitosis and progression through early mitotic stages in higher plant cells.

    Science.gov (United States)

    del Campo, A; Giménez-Martín, G; López-Sáez, J F; de la Torre, C

    1997-11-01

    Allium cepa L. root meristems were given two short caffeine treatments spaced by 15 hours, the time which roughly corresponds to the duration of one cell cycle. In this way two subsequent cytokineses were prevented, and multinucleate cells with their in complement distributed into two, three or four nuclei were formed. Though all nuclei started to replicate synchronously in these cells, some of them (fast nuclei) completed their replication earlier than others (slow nuclei). The present report shows that two successive checkpoints operate before prometaphase in these cells. The first one prevents the entry of the fast nuclei into prophase until the slow ones have completed their replication. The second checkpoint ensures the synchronous entry into prometaphase after all nuclei have reached and finished prophase. By treating the multinucleate cells with an inhibitor of DNA synthesis at that time when fast but not slow nuclei had finished their replication, it was observed that both checkpoint mechanisms became leaky with time. Under these conditions the fast nuclei entered prophase in the presence of nuclei which were prevented from finishing the replication of their DNA. Subsequently, even prometaphase was triggered after a prolonged prophase. Finally, as expected from the presence of mitotic stages in these cells, nuclei with incompletely replicated DNA endured premature chromosome condensation. The prematurely condensed chromosomes either remained in a prometaphase-like stage until reconstitution nuclei formed or they followed the progression of the fast nuclei into metaphase and anaphase leading to the appearance of acentric chromosomal segments which after reconstitution gave rise to aneuploid nuclei containing unstable and broken DNA.

  14. A cell protection screen reveals potent inhibitors of multiple stages of the hepatitis C virus life cycle

    Science.gov (United States)

    Chockalingam, Karuppiah; Simeon, Rudo L.; Rice, Charles M.; Chen, Zhilei

    2010-01-01

    The hepatitis C virus (HCV) life cycle involves multiple steps, but most current drug candidates target only viral replication. The inability to systematically discover inhibitors targeting multiple steps of the HCV life cycle has hampered antiviral development. We present a simple screen for HCV antivirals based on the alleviation of HCV-mediated cytopathic effect in an engineered cell line—n4mBid. This approach obviates the need for a secondary screen to avoid cytotoxic false-positive hits. Application of our screen to 1280 compounds, many in clinical trials or approved for therapeutic use, yielded >200 hits. Of the 55 leading hits, 47 inhibited one or more aspects of the HCV life cycle by >40%. Six compounds blocked HCV entry to levels similar to an antibody (JS-81) targeting the HCV entry receptor CD81. Seven hits inhibited HCV replication and/or infectious virus production by >100-fold, with one (quinidine) inhibiting infectious virus production by 450-fold relative to HCV replication levels. This approach is simple and inexpensive and should enable the rapid discovery of new classes of HCV life cycle inhibitors. PMID:20142494

  15. Isolation of Plant Nuclei at Defined Cell Cycle Stages Using EdU Labeling and Flow Cytometry.

    Science.gov (United States)

    Wear, Emily E; Concia, Lorenzo; Brooks, Ashley M; Markham, Emily A; Lee, Tae-Jin; Allen, George C; Thompson, William F; Hanley-Bowdoin, Linda

    2016-01-01

    5-Ethynyl-2'-deoxyuridine (EdU) is a nucleoside analog of thymidine that can be rapidly incorporated into replicating DNA in vivo and, subsequently, detected by using "click" chemistry to couple its terminal alkyne group to fluorescent azides such as Alexa Fluor 488. Recently, EdU incorporation followed by coupling with a fluorophore has been used to visualize newly synthesized DNA in a wide range of plant species. One particularly useful application is in flow cytometry, where two-parameter sorting can be employed to analyze different phases of the cell cycle, as defined both by total DNA content and the amount of EdU pulse-labeled DNA. This approach allows analysis of the cell cycle without the need for synchronous cell populations, which can be difficult to obtain in many plant systems. The approach presented here, which was developed for fixed, EdU-labeled nuclei, can be used to prepare analytical profiles as well as to make highly purified preparations of G1, S, or G2/M phase nuclei for molecular or biochemical analysis. We present protocols for EdU pulse labeling, tissue fixation and harvesting, nuclei preparation, and flow sorting. Although developed for Arabidopsis suspension cells and maize root tips, these protocols should be modifiable to many other plant systems.

  16. Comparative myoanatomy of cycliophoran life cycle stages

    DEFF Research Database (Denmark)

    Neves, Ricardo C.; Cunha, Marina R; Funch, Peter

    2010-01-01

    The metazoan phylum Cycliophora includes small cryptic epibionts that live attached to the mouthparts of clawed lobsters. The life cycle is complex, with alternating sexual and asexual generations, and involves several sessile and free-living stages. So far, the morphological and genetic...... on the dorsal side, whereas on the ventral side, longitudinal muscles and a V-shaped muscle structure are present. These muscles are complemented by additional dorsoventral muscles. The mesodermal muscle fibers attach to the cuticle via the epidermis in all life cycle stages studied herein. The musculature...... of the female is similar to that of the Pandora larva of Symbion americanus and includes dorsoventral muscles and longitudinal muscles that run in the dorsal and ventral body region. Overall, our results reveal striking similarities in the muscular arrangement of the life cycle stages of both Symbion species. J...

  17. Sulindac and Celecoxib regulate cell cycle progression by p53/p21 up regulation to induce apoptosis during initial stages of experimental colorectal cancer.

    Science.gov (United States)

    Vaish, Vivek; Rana, Chandan; Piplani, Honit; Vaiphei, Kim; Sanyal, Sankar Nath

    2014-03-01

    In the present study we have elaborated the putative mechanisms could be followed by the non-steroidal anti-inflammatory drugs (NSAIDs) viz. Sulindac and Celecoxib in the regulation of cell cycle checkpoints along with tumor suppressor proteins to achieve their chemopreventive effects in the initial stages of experimental colorectal cancer. Male Sprague-Dawley rats were administered with 1,2-dimethylhydrazine dihydrochloride (DMH) to produce early stages of colorectal carcinogenesis. The mRNA expression profiles of various target genes were analyzed by RT-PCR and validated by quantitative real-time PCR, whereas protein expression was analyzed by Western blotting. Nuclear localization of transcription factors or other nuclear proteins was analyzed by electrophoretic mobility shift assay and immunofluorescence. Flowcytometry was performed to analyze the differential apoptotic events and cell cycle regulation. Molecular docking studies with different target proteins were also performed to deduce the various putative mechanisms of action followed by Sulindac and Celecoxib. We observed that DMH administration has abruptly increased the proliferation of colonic cells which is macroscopically visible in the form of multiple plaque lesions and co-relates with the disturbed molecular mechanisms of cell cycle regulation. However, co-administration of NSAIDs has shown regulatory effects on cell cycle checkpoints via induction of various tumor suppressor proteins. We may conclude that Sulindac and Celecoxib could possibly follow p53/p21 mediated regulation of cell proliferation, where down regulation of NF-κB signaling and activation of PPARγ might serve as important additional events in vivo.

  18. Autoradiography and the Cell Cycle.

    Science.gov (United States)

    Jones, C. Weldon

    1992-01-01

    Outlines the stages of a cell biology "pulse-chase" experiment in which the students apply autoradiography techniques to learn about the concept of the cell cycle. Includes (1) seed germination and plant growth; (2) radioactive labeling and fixation of root tips; (3) feulgen staining of root tips; (4) preparation of autoradiograms; and…

  19. Cell cycle progression score is a marker for five-year lung cancer-specific mortality risk in patients with resected stage I lung adenocarcinoma

    Science.gov (United States)

    Eguchi, Takashi; Kadota, Kyuichi; Chaft, Jamie; Evans, Brent; Kidd, John; Tan, Kay See; Dycoco, Joe; Kolquist, Kathryn; Davis, Thaylon; Hamilton, Stephanie A.; Yager, Kraig; Jones, Joshua T.; Travis, William D.; Jones, David R.; Hartman, Anne-Renee; Adusumilli, Prasad S.

    2016-01-01

    Purpose The goals of our study were (a) to validate a molecular expression signature (cell cycle progression [CCP] score and molecular prognostic score [mPS; combination of CCP and pathological stage {IA or IB}]) that identifies stage I lung adenocarcinoma (ADC) patients with a higher risk of cancer-specific death following curative-intent surgical resection, and (b) to determine whether mPS stratifies prognosis within stage I lung ADC histological subtypes. Methods Formalin-fixed, paraffin-embedded stage I lung ADC tumor samples from 1200 patients were analyzed for 31 proliferation genes by quantitative RT-PCR. Prognostic discrimination of CCP score and mPS was assessed by Cox proportional hazards regression, using 5-year lung cancer–specific mortality as the primary outcome. Results In multivariable analysis, CCP score was a prognostic marker for 5-year lung cancer–specific mortality (HR=1.6 per interquartile range; 95% CI, 1.14–2.24; P=0.006). In a multivariable model that included mPS instead of CCP, mPS was a significant prognostic marker for 5-year lung cancer–specific mortality (HR=1.77; 95% CI, 1.18–2.66; P=0.006). Five-year lung cancer–specific survival differed between low-risk and high-risk mPS groups (96% vs 81%; P<0.001). In patients with intermediate-grade lung ADC of acinar and papillary subtypes, high mPS was associated with worse 5-year lung cancer–specific survival (P<0.001 and 0.015, respectively), compared with low mPS. Conclusion This study validates CCP score and mPS as independent prognostic markers for lung cancer–specific mortality and provides quantitative risk assessment, independent of known high-risk features, for stage I lung ADC patients treated with surgery alone. PMID:27153551

  20. Role of Artemis in DSB repair and guarding chromosomal stability following exposure to ionizing radiation at different stages of cell cycle.

    Science.gov (United States)

    Darroudi, Firouz; Wiegant, Wouter; Meijers, Matty; Friedl, Anna A; van der Burg, Mirjam; Fomina, Janna; van Dongen, Jacques J M; van Gent, Dik C; Zdzienicka, Małgorzata Z

    2007-02-03

    We analyzed the phenotype of cells derived from SCID patients with different mutations in the Artemis gene. Using clonogenic survival assay an increased sensitivity was found to X-rays (2-3-fold) and bleomycin (2-fold), as well as to etoposide, camptothecin and methylmethane sulphonate (up to 1.5-fold). In contrast, we did not find increased sensitivity to cross-linking agents mitomycin C and cis-platinum. The kinetics of DSB repair assessed by pulsed-field gel electrophoresis and gammaH2AX foci formation after ionizing irradiation, indicate that 15-20% of DSB are not repaired in Artemis-deficient cells. In order to get a better understanding of the repair defect in Artemis-deficient cells, we studied chromosomal damage at different stages of the cell cycle. In contrast to AT cells, Artemis-deficient cells appear to have a normal G(1)/S-block that resulted in a similar frequency of dicentrics and translocations, however, frequency of acentrics fragments was found to be 2-4-fold higher compared to normal fibroblasts. Irradiation in G(2) resulted in a higher frequency of chromatid-type aberrations (1.5-3-fold) than in normal cells, indicating that a fraction of DSB requires Artemis for proper repair. Our data are consistent with a function of Artemis protein in processing of a subset of complex DSB, without G(1) cell cycle checkpoint defects. This type of DSB can be induced in high proportion and persist through S-phase and in part might be responsible for the formation of chromatid-type exchanges in G(1)-irradiated Artemis-deficient cells. Among different human radiosensitive fibroblasts studied for endogenous (in untreated samples) as well as X-ray-induced DNA damage, the ranking order on the basis of higher incidence of spontaneously occurring chromosomal alterations and induced ones was: ligase 4> or =AT>Artemis. This observation implicates that in human fibroblasts following exposure to ionizing radiation a lower risk might be created when cells are devoid of

  1. Role of Artemis in DSB repair and guarding chromosomal stability following exposure to ionizing radiation at different stages of cell cycle

    Energy Technology Data Exchange (ETDEWEB)

    Darroudi, Firouz [Department of Toxicogenetics, Leiden University Medical Centre, Einthovenweg 20, 2300RC Leiden (Netherlands)]. E-mail: F.Darroudi@LUMC.NL; Wiegant, Wouter [Department of Toxicogenetics, Leiden University Medical Centre, Einthovenweg 20, 2300RC Leiden (Netherlands); Meijers, Matty [Department of Toxicogenetics, Leiden University Medical Centre, Einthovenweg 20, 2300RC Leiden (Netherlands); Friedl, Anna A. [Radiobiological Institute, University of Munich, Munich (Germany); Institute of Radiobiology, GSF National Research Center for Environment and Health, Neuherberg (Germany); Burg, Mirjam van der [Department of Immunology, Erasmus Medical Centre, Rotterdam (Netherlands); Fomina, Janna [Department of Toxicogenetics, Leiden University Medical Centre, Einthovenweg 20, 2300RC Leiden (Netherlands); Dongen, Jacques J.M. van [Department of Immunology, Erasmus Medical Centre, Rotterdam (Netherlands); Gent, Dik C. van [Department of Cell Biology and Genetics, Erasmus Medical Centre, Rotterdam (Netherlands); Zdzienicka, Malgorzata Z. [Department of Toxicogenetics, Leiden University Medical Centre, Einthovenweg 20, 2300RC Leiden (Netherlands); Department of Molecular Cell Genetics, Collegium Medicum, N. Corpernicus University, Bydgoszcz (Poland)

    2007-02-03

    We analyzed the phenotype of cells derived from SCID patients with different mutations in the Artemis gene. Using clonogenic survival assay an increased sensitivity was found to X-rays (2-3-fold) and bleomycin (2-fold), as well as to etoposide, camptothecin and methylmethane sulphonate (up to 1.5-fold). In contrast, we did not find increased sensitivity to cross-linking agents mitomycin C and cis-platinum. The kinetics of DSB repair assessed by pulsed-field gel electrophoresis and {gamma}H2AX foci formation after ionizing irradiation, indicate that 15-20% of DSB are not repaired in Artemis-deficient cells. In order to get a better understanding of the repair defect in Artemis-deficient cells, we studied chromosomal damage at different stages of the cell cycle. In contrast to AT cells, Artemis-deficient cells appear to have a normal G{sub 1}/S-block that resulted in a similar frequency of dicentrics and translocations, however, frequency of acentrics fragments was found to be 2-4-fold higher compared to normal fibroblasts. Irradiation in G{sub 2} resulted in a higher frequency of chromatid-type aberrations (1.5-3-fold) than in normal cells, indicating that a fraction of DSB requires Artemis for proper repair. Our data are consistent with a function of Artemis protein in processing of a subset of complex DSB, without G{sub 1} cell cycle checkpoint defects. This type of DSB can be induced in high proportion and persist through S-phase and in part might be responsible for the formation of chromatid-type exchanges in G{sub 1}-irradiated Artemis-deficient cells. Among different human radiosensitive fibroblasts studied for endogenous (in untreated samples) as well as X-ray-induced DNA damage, the ranking order on the basis of higher incidence of spontaneously occurring chromosomal alterations and induced ones was: ligase 4 {>=} AT > Artemis. This observation implicates that in human fibroblasts following exposure to ionizing radiation a lower risk might be created when

  2. 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.

  3. The hybrid two stage anticlockwise cycle for ecological energy conversion

    Directory of Open Access Journals (Sweden)

    Cyklis Piotr

    2016-01-01

    Full Text Available The anticlockwise cycle is commonly used for refrigeration, air conditioning and heat pumps applications. The application of refrigerant in the compression cycle is within the temperature limits of the triple point and the critical point. New refrigerants such as 1234yf or 1234ze have many disadvantages, therefore natural refrigerants application is favourable. The carbon dioxide and water can be applied only in the hybrid two stages cycle. The possibilities of this solutions are shown for refrigerating applications, as well some experimental results of the adsorption-compression double stages cycle, powered with solar collectors are shown. As a high temperature cycle the adsorption system is applied. The low temperature cycle is the compression stage with carbon dioxide as a working fluid. This allows to achieve relatively high COP for low temperature cycle and for the whole system.

  4. Cell cycle gene expression under clinorotation

    Science.gov (United States)

    Artemenko, Olga

    2016-07-01

    Cyclins and cyclin-dependent kinase (CDK) are main regulators of the cell cycle of eukaryotes. It's assumes a significant change of their level in cells under microgravity conditions and by other physical factors actions. The clinorotation use enables to determine the influence of gravity on simulated events in the cell during the cell cycle - exit from the state of quiet stage and promotion presynthetic phase (G1) and DNA synthesis phase (S) of the cell cycle. For the clinorotation effect study on cell proliferation activity is the necessary studies of molecular mechanisms of cell cycle regulation and development of plants under altered gravity condition. The activity of cyclin D, which is responsible for the events of the cell cycle in presynthetic phase can be controlled by the action of endogenous as well as exogenous factors, but clinorotation is one of the factors that influence on genes expression that regulate the cell cycle.These data can be used as a model for further research of cyclin - CDK complex for study of molecular mechanisms regulation of growth and proliferation. In this investigation we tried to summarize and analyze known literature and own data we obtained relatively the main regulators of the cell cycle in altered gravity condition.

  5. Changes in the micro- and nanostructure of siliceous valves in the diatom Synedra acus under the effect of colchicine treatment at different stages of the cell cycle.

    Science.gov (United States)

    Kharitonenko, Ksenia V; Bedoshvili, Yekaterina D; Likhoshway, Yelena V

    2015-04-01

    The important role of the cytoskeleton in the morphogenesis of siliceous frustule components, which are synthesized within the diatom cells, has been revealed due to experiments with microtubule inhibitors. It has been shown that colchicine entering the diatom cell inhibits polymerization of tubulin, the main protein of microtubules, thereby disrupting the normal processes of biogenic silica deposition and daughter valve morphogenesis. In this study, experiments with a synchronized culture of the pennate diatom Synedra acus have been performed to determine the timing and duration of the formation of various valve components and analyze the effect of colchicine at a subtoxic concentration on the structure of daughter valves at different stages of their morphogenesis. Electron microscopic analysis has revealed several types of micro- and nanoscale anomalies in daughter valve morphology, with their frequency varying depending on the time of colchicine treatment. Laser scanning microscopy of preparations vitally stained with Tubulin Tracker Green has shown that polymerized tubulin at early stages of valve morphogenesis is localized along the periphery of the developing valve. This is evidence for an important role of microtubules in the horizontal growth of the valve at the stage when its general structural pattern is established, including its shape and arrangement of basic micro- and nanostructures. Treatment with a microtubule inhibitor at a certain stage of valve morphogenesis makes it possible to obtain new forms with a specific structure of siliceous components that hold promise for use in nanotechnologies.

  6. Two-stage, self-cycling process for the production of bacteriophages

    Directory of Open Access Journals (Sweden)

    Cooper David G

    2010-11-01

    Full Text Available Abstract Background A two-stage, self-cycling process for the production of bacteriophages was developed. The first stage, containing only the uninfected host bacterium, was operated under self-cycling fermentation (SCF conditions. This automated method, using the derivative of the carbon dioxide evolution rate (CER as the control parameter, led to the synchronization of the host bacterium. The second stage, containing both the host and the phage, was operated using self-cycling infection (SCI with CER and CER-derived data as the control parameters. When each infection cycle was terminated, phages were harvested and a new infection cycle was initiated by adding host cells from the SCF (first stage. This was augmented with fresh medium and the small amount of phages left from the previous cycle initiated the next infection cycle. Both stages were operated independently, except for this short period of time when the SCF harvest was added to the SCI to initiate the next cycle. Results It was demonstrated that this mode of operation resulted in stable infection cycles if the growth of the host cells in the SCF was synchronized. The final phage titers obtained were reproducible among cycles and were as good as those obtained in batch productions performed under the same conditions (medium, temperature, initial multiplicity of infection, etc.. Moreover, phages obtained in different cycles showed no important difference in infectivity. Finally, it was shown that cell synchronization of the host cells in the first stage (SCF not only maintained the volumetric productivity (phages per volume but also led to higher specific productivity (phage per cell per hour in the second stage (SCI. Conclusions Production of bacteriophage T4 in the semi-continuous, automated SCF/SCI system was efficient and reproducible from cycle to cycle. Synchronization of the host in the first stage prior to infection led to improvements in the specific productivity of phages in

  7. K+ channels and cell cycle progression in tumor cells

    Directory of Open Access Journals (Sweden)

    HALIMA eOUADID-AHIDOUCH

    2013-08-01

    Full Text Available K+ ions play a major role in many cellular processes. The deregulation of K+ signaling is associated with a variety of diseases such as hypertension, atherosclerosis, or diabetes. K+ ions are important for setting the membrane potential, the driving force for Ca2+ influx, and regulate volume of growing cells. Moreover, it is increasingly recognized that K+ channels control cell proliferation through a novel signaling mechanisms triggered and modulated independently of ion fluxes. In cancer, aberrant expression, regulation and/or sublocalization of K+ channels can alter the downstream signals that converge on the cell cycle machinery. Various K+ channels are involved in cell cycle progression and are needed only at particular stages of the cell cycle. Consistent with this idea, the expression of Eag1 and HERG channels fluctuate along the cell cycle. Despite of acquired knowledge, our understanding of K+ channels functioning in cancer cells requires further studies. These include identifying the molecular mechanisms controling the cell cycle machinery. By understanding how K+ channels regulate cell cycle progression in cancer cells, we will gain insights into how cancer cells subvert the need for K+ signal and its downstream targets to proliferate.

  8. Alteration of cell cycle progression by Sindbis virus infection

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Ruirong; Saito, Kengo [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Isegawa, Naohisa [Laboratory Animal Center, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan); Shirasawa, Hiroshi, E-mail: sirasawa@faculty.chiba-u.jp [Department of Molecular Virology, Graduate School of Medicine, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chiba 260-8670 (Japan)

    2015-07-10

    We examined the impact of Sindbis virus (SINV) infection on cell cycle progression in a cancer cell line, HeLa, and a non-cancerous cell line, Vero. Cell cycle analyses showed that SINV infection is able to alter the cell cycle progression in both HeLa and Vero cells, but differently, especially during the early stage of infection. SINV infection affected the expression of several cell cycle regulators (CDK4, CDK6, cyclin E, p21, cyclin A and cyclin B) in HeLa cells and caused HeLa cells to accumulate in S phase during the early stage of infection. Monitoring SINV replication in HeLa and Vero cells expressing cell cycle indicators revealed that SINV which infected HeLa cells during G{sub 1} phase preferred to proliferate during S/G{sub 2} phase, and the average time interval for viral replication was significantly shorter in both HeLa and Vero cells infected during G{sub 1} phase than in cells infected during S/G{sub 2} phase. - Highlights: • SINV infection was able to alter the cell cycle progression of infected cancer cells. • SINV infection can affect the expression of cell cycle regulators. • SINV infection exhibited a preference for the timing of viral replication among the cell cycle phases.

  9. What cycles the cell? -Robust autonomous cell cycle models.

    Science.gov (United States)

    Lavi, Orit; Louzoun, Yoram

    2009-12-01

    The cell cycle is one of the best studied cellular mechanisms at the experimental and theoretical levels. Although most of the important biochemical components and reactions of the cell cycle are probably known, the precise way the cell cycle dynamics are driven is still under debate. This phenomenon is not atypical to many other biological systems where the knowledge of the molecular building blocks and the interactions between them does not lead to a coherent picture of the appropriate dynamics. We here propose a methodology to develop plausible models for the driving mechanisms of embryonic and cancerous cell cycles. We first define a key property of the system (a cyclic behaviour in the case of the embryonic cell cycle) and set mathematical constraints on the types of two variable simplified systems robustly reproducing such a cyclic behaviour. We then expand these robust systems to three variables and reiterate the procedure. At each step, we further limit the type of expanded systems to fit the known microbiology until a detailed description of the system is obtained. This methodology produces mathematical descriptions of the required biological systems that are more robust to changes in the precise function and rate constants. This methodology can be extended to practically any type of subcellular mechanism.

  10. Variety in intracellular diffusion during the cell cycle

    DEFF Research Database (Denmark)

    Selhuber-Unkel, C.; Yde, P.; Berg-Sørensen, Kirstine;

    2009-01-01

    During the cell cycle, the organization of the cytoskeletal network undergoes dramatic changes. In order to reveal possible changes of the viscoelastic properties in the intracellular space during the cell cycle we investigated the diffusion of endogenous lipid granules within the fission yeast...... Schizosaccharomyces Pombe using optical tweezers. The cell cycle was divided into interphase and mitotic cell division, and the mitotic cell division was further subdivided in its stages. During all stages of the cell cycle, the granules predominantly underwent subdiffusive motion, characterized by an exponent...... a that is also linked to the viscoelastic moduli of the cytoplasm. The exponent a was significantly smaller during interphase than during any stage of the mitotic cell division, signifying that the cytoplasm was more elastic during interphase than during division. We found no significant differences...

  11. Cell cycling and patterned cell proliferation in the wing primordium of Drosophila.

    OpenAIRE

    1996-01-01

    The pattern of cell proliferation in the Drosophila imaginal wing primordium is spatially and temporally heterogeneous. Direct visualization of cells in S, G2, and mitosis phases of the cell cycle reveals several features invariant throughout development. The fraction of cells in the disc in the different cell cycle stages is constant, the majority remaining in G1. Cells in the different phases of the cell cycle mainly appear in small synchronic clusters that are nonclonally derived but resul...

  12. Planning Social Expenses by Product Life Cycle Stages

    OpenAIRE

    Ludmyla Shvets

    2013-01-01

    Social spending is among the components of the total cost of every unit produced. Their planning and valuation is appropriate for the purpose of reaching the maximum social effect against the minimum costs of the business resources. For estimation of social costs as well as for defining their internal structure, the Article suggests keeping records and planning social costs by the product life cycle stages. According to the author, the proposed method of cost planning will make it possible to...

  13. TRIM E3 ligases interfere with early and late stages of the retroviral life cycle.

    Directory of Open Access Journals (Sweden)

    Pradeep D Uchil

    2008-02-01

    Full Text Available Members of the TRIpartite interaction Motif (TRIM family of E3 ligases have been shown to exhibit antiviral activities. Here we report a near comprehensive screen for antiretroviral activities of 55 TRIM proteins (36 human, 19 mouse. We identified approximately 20 TRIM proteins that, when transiently expressed in HEK293 cells, affect the entry or release of human immunodeficiency virus 1 (HIV, murine leukemia virus (MLV, or avian leukosis virus (ALV. While TRIM11 and 31 inhibited HIV entry, TRIM11 enhanced N-MLV entry by interfering with Ref1 restriction. Strikingly, many TRIM proteins affected late stages of the viral life cycle. Gene silencing of endogenously expressed TRIM 25, 31, and 62 inhibited viral release indicating that they play an important role at late stages of the viral life cycle. In contrast, downregulation of TRIM11 and 15 enhanced virus release suggesting that these proteins contribute to the endogenous restriction of retroviruses in cells.

  14. 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 ...

  15. Heat production of mammalian cells at different cell-cycle phases

    NARCIS (Netherlands)

    Loesberg, C.; Miltenburg, J.C. van; Wuk, R. van

    1982-01-01

    1. 1.|Heat production of Reuber H35 rat hepatoma cells and murine C1300 neuroblastoma cells at different stages of the cell cycle were measured microcalorimetrically. 2. 2.|Reuber H35 monolayer cultures of G1-phase cells and cells in S-phase were trypsinized, reincubated in suspension culture and i

  16. Brucella abortus Cell Cycle and Infection Are Coordinated.

    Science.gov (United States)

    De Bolle, Xavier; Crosson, Sean; Matroule, Jean-Yves; Letesson, Jean-Jacques

    2015-12-01

    Brucellae are facultative intracellular pathogens. The recent development of methods and genetically engineered strains allowed the description of cell-cycle progression of Brucella abortus, including unipolar growth and the ordered initiation of chromosomal replication. B. abortus cell-cycle progression is coordinated with intracellular trafficking in the endosomal compartments. Bacteria are first blocked at the G1 stage, growth and chromosome replication being resumed shortly before reaching the intracellular proliferation compartment. The control mechanisms of cell cycle are similar to those reported for the bacterium Caulobacter crescentus, and they are crucial for survival in the host cell. The development of single-cell analyses could also be applied to other bacterial pathogens to investigate their cell-cycle progression during infection.

  17. Molecular ties between the cell cycle and differentiation in embryonic stem cells.

    Science.gov (United States)

    Li, Victor C; Kirschner, Marc W

    2014-07-01

    Attainment of the differentiated state during the final stages of somatic cell differentiation is closely tied to cell cycle progression. Much less is known about the role of the cell cycle at very early stages of embryonic development. Here, we show that molecular pathways involving the cell cycle can be engineered to strongly affect embryonic stem cell differentiation at early stages in vitro. Strategies based on perturbing these pathways can shorten the rate and simplify the lineage path of ES differentiation. These results make it likely that pathways involving cell proliferation intersect at various points with pathways that regulate cell lineages in embryos and demonstrate that this knowledge can be used profitably to guide the path and effectiveness of cell differentiation of pluripotent cells.

  18. "Constructing" the Cell Cycle in 3D

    Science.gov (United States)

    Koc, Isil; Turan, Merve

    2012-01-01

    The cycle of duplication and division, known as the "cell cycle," is the essential mechanism by which all living organisms reproduce. This activity allows students to develop an understanding of the main events that occur during the typical eukaryotic cell cycle mostly in the process of mitotic phase that divides the duplicated genetic material…

  19. Epigenetic dynamics across the cell cycle

    DEFF Research Database (Denmark)

    Kheir, Tony Bou; Lund, Anders H.

    2010-01-01

    Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle...... a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle....

  20. Stages of Merkel Cell Carcinoma

    Science.gov (United States)

    ... when Merkel cells grow out of control. Merkel cell carcinoma starts most often in areas of skin exposed to the sun, especially the head and neck, as well as the arms, legs, and trunk. Enlarge Anatomy of the skin showing the epidermis, ...

  1. Cell cycles and proliferation patterns in Haematococcus pluvialis

    Science.gov (United States)

    Zhang, Chunhui; Liu, Jianguo; Zhang, Litao

    2016-09-01

    Most studies on Haematococcus pluvialis have been focused on cell growth and astaxanthin accumulation; far less attention has been paid to cell cycles and proliferation patterns. The purpose of this study was to clarify cell cycles and proliferation patterns in H. pluvialis microscopically using a camera and video recorder system. The complicated life history of H. pluvialis can be divided into two stages: the motile stage and the non-motile stage. All the cells can be classified into forms as follows: motile cell, non-motile cell, zoospore and aplanospore. The main cell proliferation, both in the motile phase and non-motile phase in H. pluvialis, is by asexual reproduction. Under normal growth conditions, a motile cell usually produces two, sometimes four, and exceptionally eight zoospores. Under unfavorable conditions, the motile cell loses its flagella and transforms into a non-motile cell, and the non-motile cell usually produces 2, 4 or 8 aplanospores, and occasionally 20-32 aplanospores, which further develop into non-motile cells. Under suitable conditions, the non-motile cell is also able to release zoospores. The larger non-motile cells produce more than 16 zoospores, and the smaller ones produce 4 or 8 zoospores. Vegetative reproduction is by direct cell division in the motile phase and by occasional cell budding in the non-motile phase. There is, as yet, no convincing direct evidence for sexual reproduction.

  2. STAGING OF FUEL CELLS - PHASE II

    Energy Technology Data Exchange (ETDEWEB)

    Per Onnerud; Suresh Sriramulu

    2002-08-29

    TIAX has executed a laboratory-based development program aiming at the improvement of stationary fuel cell systems. The two-year long development program resulted in an improved understanding of staged fuel cells and inorganic proton conductors through evaluation of results from a number of laboratory tasks: (1) Development of a fuel cell modeling tool--Multi-scale model was developed, capable of analyzing the effects of materials and operating conditions; and this model allowed studying various ''what-if'' conditions for hypothetically staged fuel cells; (2) Study of new high temperature proton conductor--TIAX discovery of a new class of sulfonated inorganics capable of conducting protons when exposed to water; and study involved synthesis and conductivity measurements of novel compounds up to 140 C; (3) Electrochemical fuel cell measurements--the feasibility of staged fuel cells was tested in TIAX's fuel cell laboratories experimental design was based on results from modeling.

  3. EFFECT OF SOMATOSTATIN ON THE CELL CYCLE OF HUMAN GALLBLADDER CANCER CELL

    Institute of Scientific and Technical Information of China (English)

    李济宇; 全志伟; 张强; 刘建文

    2005-01-01

    Objective To explore the effect of somatostatin on the cell cycle of human gallbladder cancer cell. Methods Growth curve of gallbladder cancer cell was measured after somatostatin treated on gradient concentration. Simultaneously, the change of gallbladder cancer cell cycle was detected using flow cytometry.Results Concentration-dependent cell growth inhibition caused by somatostatin was detected in gallbladder cancer cell(P<0.05). Cell growth was arrested in S phase since 12h after somatostatin treated, which reached its peak at 24h, then fell down. The changes in apoptosis index of gallbladder cancer cell caused by somatostatin correlated with that's in cell cycle. Conclusion Somatostatin could inhibit the cell growth of human gallbladder cancer cell in vitro on higher concentration. It might result from inducing growth arrest in S phase in early stage and inducing apoptosis in the late stage.

  4. Fission Yeast Cell Cycle Synchronization Methods.

    Science.gov (United States)

    Tormos-Pérez, Marta; Pérez-Hidalgo, Livia; Moreno, Sergio

    2016-01-01

    Fission yeast cells can be synchronized by cell cycle arrest and release or by size selection. Cell cycle arrest synchronization is based on the block and release of temperature-sensitive cell cycle mutants or treatment with drugs. The most widely used approaches are cdc10-129 for G1; hydroxyurea (HU) for early S-phase; cdc25-22 for G2, and nda3-KM311 for mitosis. Cells can also be synchronized by size selection using centrifugal elutriation or a lactose gradient. Here we describe the methods most commonly used to synchronize fission yeast cells.

  5. Cell cycle and cell signal transduction in marine phytoplankton

    Institute of Scientific and Technical Information of China (English)

    LIU Jingwen; JIAO Nianzhi; CAI Huinong

    2006-01-01

    As unicellular phytoplankton, the growth of a marine phytoplankton population results directly from the completion of a cell cycle, therefore, cell-environment communication is an important way which involves signal transduction pathways to regulate cell cycle progression and contribute to growth, metabolism and primary production and respond to their surrounding environment in marine phytoplankton. Cyclin-CDK and CaM/Ca2+ are essentially key regulators in control of cell cycle and signal transduction pathway, which has important values on both basic research and applied biotechnology. This paper reviews progress made in this research field, which involves the identification and characterization of cyclins and cell signal transduction system, cell cycle control mechanisms in marine phytoplankton cells, cell cycle proteins as a marker of a terminal event to estimate the growth rate of phytoplankton at the species level, cell cycle-dependent toxin production of toxic algae and cell cycle progression regulated by environmental factors.

  6. Impact of the cell division cycle on gene circuits

    Science.gov (United States)

    Bierbaum, Veronika; Klumpp, Stefan

    2015-12-01

    In growing cells, protein synthesis and cell growth are typically not synchronous, and, thus, protein concentrations vary over the cell division cycle. We have developed a theoretical description of genetic regulatory systems in bacteria that explicitly considers the cell division cycle to investigate its impact on gene expression. We calculate the cell-to-cell variations arising from cells being at different stages in the division cycle for unregulated genes and for basic regulatory mechanisms. These variations contribute to the extrinsic noise observed in single-cell experiments, and are most significant for proteins with short lifetimes. Negative autoregulation buffers against variation of protein concentration over the division cycle, but the effect is found to be relatively weak. Stronger buffering is achieved by an increased protein lifetime. Positive autoregulation can strongly amplify such variation if the parameters are set to values that lead to resonance-like behaviour. For cooperative positive autoregulation, the concentration variation over the division cycle diminishes the parameter region of bistability and modulates the switching times between the two stable states. The same effects are seen for a two-gene mutual-repression toggle switch. By contrast, an oscillatory circuit, the repressilator, is only weakly affected by the division cycle.

  7. Biopsy of human morula-stage embryos: outcome of 215 IVF/ICSI cycles with PGS.

    Directory of Open Access Journals (Sweden)

    Elena E Zakharova

    Full Text Available Preimplantation genetic diagnosis (PGD is commonly performed on biopsies from 6-8-cell-stage embryos or blastocyst trophectoderm obtained on day 3 or 5, respectively. Day 4 human embryos at the morula stage were successfully biopsied. Biopsy was performed on 709 morulae from 215 ICSI cycles with preimplantation genetic screening (PGS, and 3-7 cells were obtained from each embryo. The most common vital aneuploidies (chromosomes X/Y, 21 were screened by fluorescence in situ hybridization (FISH. No aneuploidy was observed in 72.7% of embryos, 91% of those developed to blastocysts. Embryos were transferred on days 5-6. Clinical pregnancy was obtained in 32.8% of cases, and 60 babies were born. Patients who underwent ICSI/PGS treatment were compared with those who underwent standard ICSI treatment by examining the percentage of blastocysts, pregnancy rate, gestational length, birth height and weight. No significant differences in these parameters were observed between the groups. Day 4 biopsy procedure does not adversely affect embryo development in vitro or in vivo. The increased number of cells obtained by biopsy of morulae might facilitate diagnostic screening. There is enough time after biopsy to obtain PGD results for embryo transfer on day 5-6 in the current IVF cycle.

  8. DNA repair by nonhomologous end joining and homologous recombination during cell cycle in human cells

    Science.gov (United States)

    Mao, Zhiyong; Bozzella, Michael; Seluanov, Andrei; Gorbunova, Vera

    2009-01-01

    DNA double-strand breaks (DSBs) are dangerous lesions that can lead to potentially oncogenic genomic rearrangements or cell death. The two major pathways for repair of DSBs are nonhomologous end joining (NHEJ) and homologous recombination (HR). NHEJ is an intrinsically error-prone pathway while HR results in accurate repair. To understand the origin of genomic instability in human cells it is important to know the contribution of each DSB repair pathway. Studies of rodent cells and human cancer cell lines have shown that the choice between NHEJ or HR pathways depends on cell cycle stage. Surprisingly, cell cycle regulation of DSB repair has not been examined in normal human cells with intact cell cycle checkpoints. Here we measured the efficiency of NHEJ and HR at different cell cycle stages in hTERT-immortalized diploid human fibroblasts. We utilized cells with chromosomally-integrated fluorescent reporter cassettes, in which a unique DSB is introduced by a rare-cutting endonuclease. We show that NHEJ is active throughout the cell cycle, and its activity increases as cells progress from G1 to G2/M (G1cell cycle stages. We conclude that human somatic cells utilize error-prone NHEJ as the major DSB repair pathway at all cell cycle stages, while HR is used, primarily, in the S phase. PMID:18769152

  9. Systematic Characterization of Cell Cycle Phase-dependent Protein Dynamics and Pathway Activities by High-content Microscopy-assisted Cell Cycle Phenotyping

    Institute of Scientific and Technical Information of China (English)

    Christopher Bruhn; Torsten Kroll; Zhao-Qi Wang

    2014-01-01

    Cell cycle progression is coordinated with metabolism, signaling and other complex cel-lular functions. The investigation of cellular processes in a cell cycle stage-dependent manner is often the subject of modern molecular and cell biological research. Cell cycle synchronization and immunostaining of cell cycle markers facilitate such analysis, but are limited in use due to unphysiological experimental stress, cell type dependence and often low flexibility. Here, we describe high-content microscopy-assisted cell cycle phenotyping (hiMAC), which integrates high-resolution cell cycle profiling of asynchronous cell populations with immunofluorescence microscopy. hiMAC is compatible with cell types from any species and allows for statistically pow-erful, unbiased, simultaneous analysis of protein interactions, modifications and subcellular locali-zation at all cell cycle stages within a single sample. For illustration, we provide a hiMAC analysis pipeline tailored to study DNA damage response and genomic instability using a 3–4-day protocol, which can be adjusted to any other cell cycle stage-dependent analysis.

  10. HAEMOGRAM OF NIGERIAN MONGREL BITCH AT DIFFERENT STAGES OF THE REPRODUCTIVE CYCLE

    Directory of Open Access Journals (Sweden)

    G. D. Mshelia, J. D. Amin and S. U. R. Chaudhari

    2005-01-01

    Full Text Available The haematologic parameters of the Nigerian Mongrel bitch were investigated at different stages of the reproductive cycle to determine their clinical values. Results showed that red blood cell (RBC counts were highest during anoestrus, with a mean of 5.09  0.62 x 106/µL, while lowest values were recorded during pregnancy, the difference was significant (P<0.05. White blood cell (WBC counts, packed cell volume (PCV and haemoglobin concentration (Hb showed an increasing pattern from anoestrus to proestrus and then decreased with transition from proestrus to oestrus. Total WBC counts were highest during dioestrus and almost twice the value recorded in pregnancy. It appears that WBC count may be used for pregnancy diagnosis in the Nigerian Mongrel bitch.

  11. Lactobacillus decelerates cervical epithelial cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Katarina Vielfort

    Full Text Available We investigated cell cycle progression in epithelial cervical ME-180 cells during colonization of three different Lactobacillus species utilizing live cell microscopy, bromodeoxyuridine incorporation assays, and flow cytometry. The colonization of these ME-180 cells by L. rhamnosus and L. reuteri, originating from human gastric epithelia and saliva, respectively, was shown to reduce cell cycle progression and to cause host cells to accumulate in the G1 phase of the cell cycle. The G1 phase accumulation in L. rhamnosus-colonized cells was accompanied by the up-regulation and nuclear accumulation of p21. By contrast, the vaginal isolate L. crispatus did not affect cell cycle progression. Furthermore, both the supernatants from the lactic acid-producing L. rhamnosus colonies and lactic acid added to cell culture media were able to reduce the proliferation of ME-180 cells. In this study, we reveal the diversity of the Lactobacillus species to affect host cell cycle progression and demonstrate that L. rhamnosus and L. reuteri exert anti-proliferative effects on human cervical carcinoma cells.

  12. High-Cycle-Life Lithium Cell

    Science.gov (United States)

    Yen, S. P. S.; Carter, B.; Shen, D.; Somoano, R.

    1985-01-01

    Lithium-anode electrochemical cell offers increased number of charge/ discharge cycles. Cell uses components selected for compatibility with electrolyte solvent: These materials are wettable and chemically stable. Low vapor pressure and high electrochemical stability of solvent improve cell packaging, handling, and safety. Cell operates at modest temperatures - less than 100 degrees C - and is well suited to automotive, communications, and other applications.

  13. Microfluidic Cell Cycle Analysis of Spread Cells by DAPI Staining

    Directory of Open Access Journals (Sweden)

    Jing Sun

    2017-01-01

    Full Text Available Single-cell cell cycle analysis is an emerging technique that requires detailed exploration of the image analysis process. In this study, we established a microfluidic single-cell cell cycle analysis method that can analyze cells in small numbers and in situ on a microfluidic chip. In addition, factors that influenced the analysis were carefully investigated. U87 or HeLa cells were seeded and attached to microfluidic channels before measurement. Cell nucleic DNA was imaged by 4′-6-diamidino-2-phenylindole (DAPI staining under a fluorescent microscope and subsequently fluorescent intensities of the cell nuclei DNA were converted to depict histograms for cell cycle phases. DAPI concentration, microscopic magnification, exposure time and cell number were examined for optimal cell cycle analysis conditions. The results showed that as few as a few hundred cells could be measured by DAPI staining in the range of 0.4–0.6 μg/mL to depict histograms with typical cell cycle phase distribution. Microscopic magnification during image acquisition, however, could distort the phase distribution. Exposure time did not significantly affect the cell cycle analysis. Furthermore, cell cycle inhibitor rapamycin treatment changed the cell cycle phase distribution as expected. In conclusion, a method for microfluidic single-cell cell cycle analysis of spread cells in situ was developed. Factors such as dye concentration and microscopic magnification had more influence on cell cycle phase distribution. Further studies will focus on detail differentiation of cell cycle phases and the application of such a method for biological meanings.

  14. Nucleosome architecture throughout the cell cycle.

    Science.gov (United States)

    Deniz, Özgen; Flores, Oscar; Aldea, Martí; Soler-López, Montserrat; Orozco, Modesto

    2016-01-28

    Nucleosomes provide additional regulatory mechanisms to transcription and DNA replication by mediating the access of proteins to DNA. During the cell cycle chromatin undergoes several conformational changes, however the functional significance of these changes to cellular processes are largely unexplored. Here, we present the first comprehensive genome-wide study of nucleosome plasticity at single base-pair resolution along the cell cycle in Saccharomyces cerevisiae. We determined nucleosome organization with a specific focus on two regulatory regions: transcription start sites (TSSs) and replication origins (ORIs). During the cell cycle, nucleosomes around TSSs display rearrangements in a cyclic manner. In contrast to gap (G1 and G2) phases, nucleosomes have a fuzzier organization during S and M phases, Moreover, the choreography of nucleosome rearrangements correlate with changes in gene expression during the cell cycle, indicating a strong association between nucleosomes and cell cycle-dependent gene functionality. On the other hand, nucleosomes are more dynamic around ORIs along the cell cycle, albeit with tighter regulation in early firing origins, implying the functional role of nucleosomes on replication origins. Our study provides a dynamic picture of nucleosome organization throughout the cell cycle and highlights the subsequent impact on transcription and replication activity.

  15. A Coarse Estimation of Cell Size Region from a Mesoscopic Stochastic Cell Cycle Model

    Institute of Scientific and Technical Information of China (English)

    YI Ming; JIA Ya; LIU Quan; ZHU Chun-Lian; YANG Li-Jian

    2007-01-01

    Based on a deterministic cell cycle model of fission yeast, the effects of the finite cell size on the cell cycle regulation in wee1- cdc25△ double mutant type are numerically studied by using of the chemical Langevin equations. It is found that at a certain region of cell size, our numerical results from the chemical Langevin equations are in good qualitative agreement with the experimental observations. The two resettings to the G2 phase from early stages of mitosis can be induced under the moderate cell size. The quantized cycle times can be observed during such a cell size region. Therefore, a coarse estimation of cell size is obtained from the mesoscopic stochastic cell cycle model.

  16. A Coarse Estimation of Cell Size Region from a Mesoscopic Stochastic Cell Cycle Model

    Science.gov (United States)

    Yi, Ming; Jia, Ya; Liu, Quan; Zhu, Chun-Lian; Yang, Li-Jian

    2007-07-01

    Based on a deterministic cell cycle model of fission yeast, the effects of the finite cell size on the cell cycle regulation in wee1- cdc25Δ double mutant type are numerically studied by using of the chemical Langevin equations. It is found that at a certain region of cell size, our numerical results from the chemical Langevin equations are in good qualitative agreement with the experimental observations. The two resettings to the G2 phase from early stages of mitosis can be induced under the moderate cell size. The quantized cycle times can be observed during such a cell size region. Therefore, a coarse estimation of cell size is obtained from the mesoscopic stochastic cell cycle model.

  17. Cell cycle features of primate embryonic stem cells.

    Science.gov (United States)

    Fluckiger, Anne-Catherine; Marcy, Guillaume; Marchand, Mélanie; Négre, Didier; Cosset, François-Loïc; Mitalipov, Shoukhrat; Wolf, Don; Savatier, Pierre; Dehay, Colette

    2006-03-01

    Using flow cytometry measurements combined with quantitative analysis of cell cycle kinetics, we show that rhesus monkey embryonic stem cells (ESCs) are characterized by an extremely rapid transit through the G1 phase, which accounts for 15% of the total cell cycle duration. Monkey ESCs exhibit a non-phasic expression of cyclin E, which is detected during all phases of the cell cycle, and do not growth-arrest in G1 after gamma-irradiation, reflecting the absence of a G1 checkpoint. Serum deprivation or pharmacological inhibition of mitogen-activated protein kinase kinase (MEK) did not result in any alteration in the cell cycle distribution, indicating that ESC growth does not rely on mitogenic signals transduced by the Ras/Raf/MEK pathway. Taken together, these data indicate that rhesus monkey ESCs, like their murine counterparts, exhibit unusual cell cycle features in which cell cycle control mechanisms operating during the G1 phase are reduced or absent.

  18. Cell cycle activation by plant parasitic nematodes

    NARCIS (Netherlands)

    Goverse, A.; Almeida Engler, de J.; Verhees, J.; Krol, van der S.; Helder, J.; Gheysen, G.

    2000-01-01

    Sedentary nematodes are important pests of crop plants. They are biotrophic parasites that can induce the (re)differentiation of either differentiated or undifferentiated plant cells into specialized feeding cells. This (re)differentiation includes the reactivation of the cell cycle in specific plan

  19. Configuration Consideration for Expander in Transcritical Carbon Dioxide Two-Stage Compression Cycle

    Institute of Scientific and Technical Information of China (English)

    MA Yitai; YANG Junlan; GUAN Haiqing; LI Minxia

    2005-01-01

    To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve the system efficiency. The expander and the compressor are connected to the same shaft and integrated into one unit, with the latter being driven by the former, thus the transfer loss and leakage loss can be decreased greatly. In these systems, the expander can be either connected with the first stage compressor (shortened as DCDL cycle) or the second stage compressor (shortened as DCDH cycle), but the two configuration ways can get different performances. By setting up theoretical model for two kinds of expander configuration ways in the transcritical carbon dioxide two-stage compression cycle, the first and the second laws of thermodynamics are used to analyze the coefficient of performance, exergy efficiency, inter-stage pressure, discharge temperature and exergy losses of each component for the two cycles. From the model results, the performance of DCDH cycle is better than that of DCDL cycle. The analysis results are indispensable to providing a theoretical basis for practical design and operating.

  20. Acanthamoeba induces cell-cycle arrest in host cells.

    Science.gov (United States)

    Sissons, James; Alsam, Selwa; Jayasekera, Samantha; Kim, Kwang Sik; Stins, Monique; Khan, Naveed Ahmed

    2004-08-01

    Acanthamoeba can cause fatal granulomatous amoebic encephalitis (GAE) and eye keratitis. However, the pathogenesis and pathophysiology of these emerging diseases remain unclear. In this study, the effects of Acanthamoeba on the host cell cycle using human brain microvascular endothelial cells (HBMEC) and human corneal epithelial cells (HCEC) were determined. Two isolates of Acanthamoeba belonging to the T1 genotype (GAE isolate) and T4 genotype (keratitis isolate) were used, which showed severe cytotoxicity on HBMEC and HCEC, respectively. No tissue specificity was observed in their ability to exhibit binding to the host cells. To determine the effects of Acanthamoeba on the host cell cycle, a cell-cycle-specific gene array was used. This screened for 96 genes specific for host cell-cycle regulation. It was observed that Acanthamoeba inhibited expression of genes encoding cyclins F and G1 and cyclin-dependent kinase 6, which are proteins important for cell-cycle progression. Moreover, upregulation was observed of the expression of genes such as GADD45A and p130 Rb, associated with cell-cycle arrest, indicating cell-cycle inhibition. Next, the effect of Acanthamoeba on retinoblastoma protein (pRb) phosphorylation was determined. pRb is a potent inhibitor of G1-to-S cell-cycle progression; however, its function is inhibited upon phosphorylation, allowing progression into S phase. Western blotting revealed that Acanthamoeba abolished pRb phosphorylation leading to cell-cycle arrest at the G1-to-S transition. Taken together, these studies demonstrated for the first time that Acanthamoeba inhibits the host cell cycle at the transcriptional level, as well as by modulating pRb phosphorylation using host cell-signalling mechanisms. A complete understanding of Acanthamoeba-host cell interactions may help in developing novel strategies to treat Acanthamoeba infections.

  1. A cell cycle and nutritional checkpoint controlling bacterial surface adhesion.

    Directory of Open Access Journals (Sweden)

    Aretha Fiebig

    2014-01-01

    Full Text Available In natural environments, bacteria often adhere to surfaces where they form complex multicellular communities. Surface adherence is determined by the biochemical composition of the cell envelope. We describe a novel regulatory mechanism by which the bacterium, Caulobacter crescentus, integrates cell cycle and nutritional signals to control development of an adhesive envelope structure known as the holdfast. Specifically, we have discovered a 68-residue protein inhibitor of holdfast development (HfiA that directly targets a conserved glycolipid glycosyltransferase required for holdfast production (HfsJ. Multiple cell cycle regulators associate with the hfiA and hfsJ promoters and control their expression, temporally constraining holdfast development to the late stages of G1. HfiA further functions as part of a 'nutritional override' system that decouples holdfast development from the cell cycle in response to nutritional cues. This control mechanism can limit surface adhesion in nutritionally sub-optimal environments without affecting cell cycle progression. We conclude that post-translational regulation of cell envelope enzymes by small proteins like HfiA may provide a general means to modulate the surface properties of bacterial cells.

  2. Fuel cell hybrid taxi life cycle analysis

    Energy Technology Data Exchange (ETDEWEB)

    Baptista, Patricia, E-mail: patricia.baptista@ist.utl.pt [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Ribau, Joao; Bravo, Joao; Silva, Carla [IDMEC-Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais, 1, 1049-001 Lisboa (Portugal); Adcock, Paul; Kells, Ashley [Intelligent Energy, Charnwood Building, HolywellPark, Ashby Road, Loughborough, LE11 3GR (United Kingdom)

    2011-09-15

    A small fleet of classic London Taxis (Black cabs) equipped with hydrogen fuel cell power systems is being prepared for demonstration during the 2012 London Olympics. This paper presents a Life Cycle Analysis for these vehicles in terms of energy consumption and CO{sub 2} emissions, focusing on the impacts of alternative vehicle technologies for the Taxi, combining the fuel life cycle (Tank-to-Wheel and Well-to-Tank) and vehicle materials Cradle-to-Grave. An internal combustion engine diesel taxi was used as the reference vehicle for the currently available technology. This is compared to battery and fuel cell vehicle configurations. Accordingly, the following energy pathways are compared: diesel, electricity and hydrogen (derived from natural gas steam reforming). Full Life Cycle Analysis, using the PCO-CENEX drive cycle, (derived from actual London Taxi drive cycles) shows that the fuel cell powered vehicle configurations have lower energy consumption (4.34 MJ/km) and CO{sub 2} emissions (235 g/km) than both the ICE Diesel (9.54 MJ/km and 738 g/km) and the battery electric vehicle (5.81 MJ/km and 269 g/km). - Highlights: > A Life Cycle Analysis of alternative vehicle technologies for the London Taxi was performed. > The hydrogen powered vehicles have the lowest energy consumption and CO{sub 2} emissions results. > A hydrogen powered solution can be a sustainable alternative in a full life cycle framework.

  3. Cell cycle phase regulates glucocorticoid receptor function.

    Directory of Open Access Journals (Sweden)

    Laura Matthews

    Full Text Available The glucocorticoid receptor (GR is a member of the nuclear hormone receptor superfamily of ligand-activated transcription factors. In contrast to many other nuclear receptors, GR is thought to be exclusively cytoplasmic in quiescent cells, and only translocate to the nucleus on ligand binding. We now demonstrate significant nuclear GR in the absence of ligand, which requires nuclear localisation signal 1 (NLS1. Live cell imaging reveals dramatic GR import into the nucleus through interphase and rapid exclusion of the GR from the nucleus at the onset of mitosis, which persists into early G(1. This suggests that the heterogeneity in GR distribution is reflective of cell cycle phase. The impact of cell cycle-driven GR trafficking on a panel of glucocorticoid actions was profiled. In G2/M-enriched cells there was marked prolongation of glucocorticoid-induced ERK activation. This was accompanied by DNA template-specific, ligand-independent GR transactivation. Using chimeric and domain-deleted receptors we demonstrate that this transactivation effect is mediated by the AF1 transactivation domain. AF-1 harbours multiple phosphorylation sites, which are consensus sequences for kinases including CDKs, whose activity changes during the cell cycle. In G2/M there was clear ligand independent induction of GR phosphorylation on residues 203 and 211, both of which are phosphorylated after ligand activation. Ligand-independent transactivation required induction of phospho-S211GR but not S203GR, thereby directly linking cell cycle driven GR modification with altered GR function. Cell cycle phase therefore regulates GR localisation and post-translational modification which selectively impacts GR activity. This suggests that cell cycle phase is an important determinant in the cellular response to Gc, and that mitotic index contributes to tissue Gc sensitivity.

  4. Early stages of spindle formation and independence of chromosome and microtubule cycles in Haemanthus endosperm.

    Science.gov (United States)

    Smirnova, E A; Bajer, A S

    1998-01-01

    We analyzed transformation of the interphase microtubular cytoskeleton into the prophase spindle and followed the pattern of spindle axis determination. Microtubules in endosperm of the higher plant Haemanthus (Scadoxus) were stained by the immunogold and immunogold silver-enhanced methods. Basic structural units involved in spindle morphogenesis were "microtubule converging centers." We emphasized the importance of relative independence of chromosomal and microtubular cycles, and the influence of these cycles on the progress of mitosis. Cells with moderately desynchronized cycles were functional, but extreme desynchronization led to aberrant mitosis. There were three distinct phases of spindle development. The first one comprised interphase and early to mid-prophase. During this phase, the interphase microtubule meshwork radiating from the nuclear surface into the cytoplasm rearranged and formed a dense microtubule cage around the nucleus. The second phase comprised mid to late prophase, and resulted in the formation of normal (bipolar) or transitory aberrant (apolar or multipolar) prophase spindles. The third phase comprised late prophase with prometaphase. The onset of prometaphase was accompanied by a rapid association of microtubule converging centers with kinetochores. In this stage aberrant spindles transformed invariably into bipolar ones. Lateral association of a few bipolar kinetochore fibers at early prometaphase established the core of the bipolar spindle and its alignment. We concluded that (1) spindle formation is a largely independent microtubular process modified by the chromosomal/kinetochore cycle; and (2) the initial polarity of the spindle is established by microtubule converging centers, which are a functional substitute of the centrosome/MTOC. We believe that the dynamics of microtubule converging centers is an expression of microtubule self-organization driven by motor proteins as proposed by Mitchison [1992: Philos. Trans. R. Soc. Lond. B

  5. A stochastic spatiotemporal model of a response-regulator network in the Caulobacter crescentus cell cycle

    Science.gov (United States)

    Li, Fei; Subramanian, Kartik; Chen, Minghan; Tyson, John J.; Cao, Yang

    2016-06-01

    The asymmetric cell division cycle in Caulobacter crescentus is controlled by an elaborate molecular mechanism governing the production, activation and spatial localization of a host of interacting proteins. In previous work, we proposed a deterministic mathematical model for the spatiotemporal dynamics of six major regulatory proteins. In this paper, we study a stochastic version of the model, which takes into account molecular fluctuations of these regulatory proteins in space and time during early stages of the cell cycle of wild-type Caulobacter cells. We test the stochastic model with regard to experimental observations of increased variability of cycle time in cells depleted of the divJ gene product. The deterministic model predicts that overexpression of the divK gene blocks cell cycle progression in the stalked stage; however, stochastic simulations suggest that a small fraction of the mutants cells do complete the cell cycle normally.

  6. Final Report on Two-Stage Fast Spectrum Fuel Cycle Options

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States); Lin, C. S. [Purdue Univ., West Lafayette, IN (United States); Hader, J. S. [Purdue Univ., West Lafayette, IN (United States); Park, T. K. [Purdue Univ., West Lafayette, IN (United States); Deng, P. [Purdue Univ., West Lafayette, IN (United States); Yang, G. [Purdue Univ., West Lafayette, IN (United States); Jung, Y. S. [Purdue Univ., West Lafayette, IN (United States); Kim, T. K. [Argonne National Lab. (ANL), Argonne, IL (United States); Stauff, N. E. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-01-30

    This report presents the performance characteristics of two “two-stage” fast spectrum fuel cycle options proposed to enhance uranium resource utilization and to reduce nuclear waste generation. One is a two-stage fast spectrum fuel cycle option of continuous recycle of plutonium (Pu) in a fast reactor (FR) and subsequent burning of minor actinides (MAs) in an accelerator-driven system (ADS). The first stage is a sodium-cooled FR fuel cycle starting with low-enriched uranium (LEU) fuel; at the equilibrium cycle, the FR is operated using the recovered Pu and natural uranium without supporting LEU. Pu and uranium (U) are co-extracted from the discharged fuel and recycled in the first stage, and the recovered MAs are sent to the second stage. The second stage is a sodium-cooled ADS in which MAs are burned in an inert matrix fuel form. The discharged fuel of ADS is reprocessed, and all the recovered heavy metals (HMs) are recycled into the ADS. The other is a two-stage FR/ADS fuel cycle option with MA targets loaded in the FR. The recovered MAs are not directly sent to ADS, but partially incinerated in the FR in order to reduce the amount of MAs to be sent to the ADS. This is a heterogeneous recycling option of transuranic (TRU) elements

  7. Microfluidic Cell Cycle Analysis of Spread Cells by DAPI Staining

    OpenAIRE

    Jing Sun; Jiayu Zhang; Haibo Yang; Gongzhuo Wang; Yanzhao Li; Xuxin Zhang; Qidan Chen; Ming-Fei Lang

    2017-01-01

    Single-cell cell cycle analysis is an emerging technique that requires detailed exploration of the image analysis process. In this study, we established a microfluidic single-cell cell cycle analysis method that can analyze cells in small numbers and in situ on a microfluidic chip. In addition, factors that influenced the analysis were carefully investigated. U87 or HeLa cells were seeded and attached to microfluidic channels before measurement. Cell nucleic DNA was imaged by 4′-6-diamidino-2...

  8. SAFT nickel hydrogen cell cycling status

    Science.gov (United States)

    Borthomieu, Yannick; Duquesne, Didier

    1994-01-01

    An overview of the NiH2 cell development is given. The NiH2 SAFT system is an electrochemical (single or dual) stack (IPV). The stack is mounted in an hydroformed Inconel 718 vessel operating at high pressure, equipped with 'rabbit ears' ceramic brazed electrical feedthroughs. The cell design is described: positive electrode, negative electrode, and stack configuration. Overviews of low earth orbit and geostationary earth orbit cyclings are provided. DPA results are also provided. The cycling and DPA results demonstrate that SAFT NiH2 is characterized by high reliability and very stable performances.

  9. Organizational Life Cycle and the Growth of Information Technology Stage Theory

    Directory of Open Access Journals (Sweden)

    Jamshid Nazemi

    2012-10-01

    Full Text Available : Organizations have the different patterns of behaviors on management practice and the use of systems during their life cycle and due to rapid growth of information technology, the application of appropriate technologies is becoming an essential part of business, as well. The adaptation of appropriate management systems on different stages of organizational life period will affect on sustainability of the firms and success to move to next stage and alignment and collaboration schema of IS/IT and business requirement affects on management effectiveness at every stage. This research investigated the significance of relationship between management behavior and IS/IT usage and the generic approach selected by companies. The results showed that organizations have chosen different approach during their life cycle and as they faced with unique challenges on each stage, a common practice on using information technology and applications became part of organizational life cycle. A generic model for information technology usage on organization life cycle was also developed that will assist organizations to select and develop IS/IT plans which addresses the requirements for each stage of life cycle.

  10. Testis Morphometry and Stages of the Seminiferous Epithelium Cycle in an Epididymal Sperm-storing Neotropical Vespertilionid, Myotis levis (Chiroptera).

    Science.gov (United States)

    Farias, T O; Notini, A A; Talamoni, S A; Godinho, H P

    2015-10-01

    Yellowish myotis, Myotis levis, is a seasonal, epididymal sperm-storing Neotropical vespertilionid. In the dry season, males show simultaneous testis regression and sperm storage in cauda epididymis, enabling them to mate during this season. In this study, we investigated seasonal variations in body mass, diameter and height of seminiferous tubules and nuclei of Leydig cells in a population of southeastern Brazil. We also determined the frequencies of the stages of the seminiferous epithelium cycle (SEC) of mature individuals of this population. Body mass and diameter of Leydig cell nuclei showed no significant differences between dry and rainy seasons and stages of annual reproductive cycle; however, all other morphometric parameters varied significantly. The relative cumulative frequency of pre-meiotic stages of the SEC (1-3) was 51%, of meiotic stage (4) was 2% and of post-meiotic stages (5-8) was 47%. We confirmed that the yellowish myotis presents seasonal sperm production as revealed by testis regression and epididymal sperm storage during the dry season.

  11. Control of cell cycle and cell growth by molecular chaperones.

    Science.gov (United States)

    Aldea, Martí; Garí, Eloi; Colomina, Neus

    2007-11-01

    Cells adapt their size to both intrinsic and extrinsic demands and, among them, those that stem from growth and proliferation rates are crucial for cell size homeostasis. Here we revisit mechanisms that regulate cell cycle and cell growth in budding yeast. Cyclin Cln3, the most upstream activator of Start, is retained at the endoplasmic reticulum in early G(1) and released by specific chaperones in late G(1) to initiate the cell cycle. On one hand, these chaperones are rate-limiting for release of Cln3 and cell cycle entry and, on the other hand, they are required for key biosynthetic processes. We propose a model whereby the competition for specialized chaperones between growth and cycle machineries could gauge biosynthetic rates and set a critical size threshold at Start.

  12. 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.

  13. Effects of cell-cycle-dependent expression on random fluctuations in protein levels.

    Science.gov (United States)

    Soltani, Mohammad; Singh, Abhyudai

    2016-12-01

    Expression of many genes varies as a cell transitions through different cell-cycle stages. How coupling between stochastic expression and cell cycle impacts cell-to-cell variability (noise) in the level of protein is not well understood. We analyse a model where a stable protein is synthesized in random bursts, and the frequency with which bursts occur varies within the cell cycle. Formulae quantifying the extent of fluctuations in the protein copy number are derived and decomposed into components arising from the cell cycle and stochastic processes. The latter stochastic component represents contributions from bursty expression and errors incurred during partitioning of molecules between daughter cells. These formulae reveal an interesting trade-off: cell-cycle dependencies that amplify the noise contribution from bursty expression also attenuate the contribution from partitioning errors. We investigate the existence of optimum strategies for coupling expression to the cell cycle that minimize the stochastic component. Intriguingly, results show that a zero production rate throughout the cell cycle, with expression only occurring just before cell division, minimizes noise from bursty expression for a fixed mean protein level. By contrast, the optimal strategy in the case of partitioning errors is to make the protein just after cell division. We provide examples of regulatory proteins that are expressed only towards the end of the cell cycle, and argue that such strategies enhance robustness of cell-cycle decisions to the intrinsic stochasticity of gene expression.

  14. Regulation of 14-3-3 in the First Mitotic Cell Cycle in One-cell Stage Mouse Fertilized Eggs%14-3-3蛋白调节1-细胞期小鼠受精卵有丝分裂

    Institute of Scientific and Technical Information of China (English)

    崔城; 秦鑫; 任秀丽; 于秉治

    2013-01-01

    目的 研究14-3-3蛋白在1-细胞期小鼠受精卵有丝分裂中的作用.方法 RT-PCR技术鉴定小鼠受精卵14-3-3蛋白亚型.采用显微注射方法将14-3-3 siRNA注射入小鼠受精卵G1期,观察受精卵的卵裂率、形态学变化及MPF活性.结果 小鼠受精卵中的14-3-3蛋白亚型是14-3-3ε.小鼠受精卵注射pSUPER-14-3-3ε siRNA后,与对照组相比,卵裂率下降,有丝分裂延迟,有更多的受精卵发生形态异常,MPF活性最高值显著下降.结论 14-3-3蛋白在调节小鼠受精卵有丝分裂中发挥重要作用.%Objective To study the effects of 14-3-3 proteins in regulation of the first mitotic cell cycle in one-cell stage mouse fertilized eggs. Methods 14-3-3 isoform in the mouse fertilized eggs was identified by RT-PCR. 14-3-3 siRNA was introduced to G1 phase fertilized eggs by microinjection to study the cleavage rate, morphology and MPF activity. Results 14-3-3 ε was identified in one-cell stage of mouse fertilized eggs. Compared with the control group,the cleavage rate in pSUPER-14-3-3ε siRNA injection group was significantly decreased, mitosis was delayed and more abnormal morphology eggs were observed. Moreover, the maximal value of MPF activity was significantly decreased. Conclusion 14-3-3 proteins play critical roles in the first mitotic cell cycle in mouse fertilized eggs.

  15. Evolution of cell cycle control: same molecular machines, different regulation

    DEFF Research Database (Denmark)

    de Lichtenberg, Ulrik; Jensen, Thomas Skøt; Brunak, Søren

    2007-01-01

    Decades of research has together with the availability of whole genomes made it clear that many of the core components involved in the cell cycle are conserved across eukaryotes, both functionally and structurally. These proteins are organized in complexes and modules that are activated or deacti......Decades of research has together with the availability of whole genomes made it clear that many of the core components involved in the cell cycle are conserved across eukaryotes, both functionally and structurally. These proteins are organized in complexes and modules that are activated...... or deactivated at specific stages during the cell cycle through a wide variety of mechanisms including transcriptional regulation, phosphorylation, subcellular translocation and targeted degradation. In a series of integrative analyses of different genome-scale data sets, we have studied how these different...... layers of regulation together control the activity of cell cycle complexes and how this regulation has evolved. The results show surprisingly poor conservation of both the transcriptional and the post-translation regulation of individual genes and proteins; however, the changes in one layer of regulation...

  16. Interruption of the blood-stage cycle of the malaria parasite, Plasmodium chabaudi, by protein tyrosine kinase inhibitors

    Directory of Open Access Journals (Sweden)

    M.L. Gazarini

    2003-11-01

    Full Text Available Malaria is a devastating disease caused by a unicellular protozoan, Plasmodium, which affects 3.7 million people every year. Resistance of the parasite to classical treatments such as chloroquine requires the development of new drugs. To gain insight into the mechanisms that control Plasmodium cell cycle, we have examined the effects of kinase inhibitors on the blood-stage cycle of the rodent malaria parasite, Plasmodium chabaudi. In vitro incubation of red blood cells for 17 h at 37ºC with the inhibitors led to a decrease in the percent of infected cells, compared to control treatment, as follows: genistein (200 µM - 75%, staurosporine (1 µM - 58%, R03 (1 µM - 75%, and tyrphostins B44 (100 µM - 66% and B46 (100 µM - 68%. All these treatments were shown to retard or prevent maturation of the intraerythrocytic parasites. The diverse concentration ranges at which these inhibitors exert their effects give a clue as to the types of signals that initiate the transitions between the different developmental stages of the parasite. The present data support our hypothesis that the maturation of the intraerythrocytic cycle of malaria parasites requires phosphorylation. In this respect, we have recently reported a high Ca2+ microenvironment surrounding the parasite within red blood cells. Several kinase activities are modulated by Ca2+. The molecular identification of the targets of these kinases could provide new strategies against malaria.

  17. Cell Cycle Progression of Human Cells Cultured in Rotating Bioreactor

    Science.gov (United States)

    Parks, Kelsey

    2009-01-01

    Space flight has been shown to alter the astronauts immune systems. Because immune performance is complex and reflects the influence of multiple organ systems within the host, scientists sought to understand the potential impact of microgravity alone on the cellular mechanisms critical to immunity. Lymphocytes and their differentiated immature form, lymphoblasts, play an important and integral role in the body's defense system. T cells, one of the three major types of lymphocytes, play a central role in cell-mediated immunity. They can be distinguished from other lymphocyte types, such as B cells and natural killer cells by the presence of a special receptor on their cell surface called T cell receptors. Reported studies have shown that spaceflight can affect the expression of cell surface markers. Cell surface markers play an important role in the ability of cells to interact and to pass signals between different cells of the same phenotype and cells of different phenotypes. Recent evidence suggests that cell-cycle regulators are essential for T-cell function. To trigger an effective immune response, lymphocytes must proliferate. The objective of this project is to investigate the changes in growth of human cells cultured in rotating bioreactors and to measure the growth rate and the cell cycle distribution for different human cell types. Human lymphocytes and lymphoblasts will be cultured in a bioreactor to simulate aspects of microgravity. The bioreactor is a cylindrical culture vessel that incorporates the aspects of clinostatic rotation of a solid fluid body around a horizontal axis at a constant speed, and compensates gravity by rotation and places cells within the fluid body into a sustained free-fall. Cell cycle progression and cell proliferation of the lymphocytes will be measured for a number of days. In addition, RNA from the cells will be isolated for expression of genes related in cell cycle regulations.

  18. FUEL CELL/MICRO-TURBINE COMBINED CYCLE

    Energy Technology Data Exchange (ETDEWEB)

    Larry J. Chaney; Mike R. Tharp; Tom W. Wolf; Tim A. Fuller; Joe J. Hartvigson

    1999-12-01

    A wide variety of conceptual design studies have been conducted that describe ultra-high efficiency fossil power plant cycles. The most promising of these ultra-high efficiency cycles incorporate high temperature fuel cells with a gas turbine. Combining fuel cells with a gas turbine increases overall cycle efficiency while reducing per kilowatt emissions. This study has demonstrated that the unique approach taken to combining a fuel cell and gas turbine has both technical and economic merit. The approach used in this study eliminates most of the gas turbine integration problems associated with hybrid fuel cell turbine systems. By using a micro-turbine, and a non-pressurized fuel cell the total system size (kW) and complexity has been reduced substantially from those presented in other studies, while maintaining over 70% efficiency. The reduced system size can be particularly attractive in the deregulated electrical generation/distribution environment where the market may not demand multi-megawatt central stations systems. The small size also opens up the niche markets to this high efficiency, low emission electrical generation option.

  19. Modeling of SONOS Memory Cell Erase Cycle

    Science.gov (United States)

    Phillips, Thomas A.; MacLeod, Todd C.; Ho, Fat H.

    2011-01-01

    Utilization of Silicon-Oxide-Nitride-Oxide-Silicon (SONOS) nonvolatile semiconductor memories as a flash memory has many advantages. These electrically erasable programmable read-only memories (EEPROMs) utilize low programming voltages, have a high erase/write cycle lifetime, are radiation hardened, and are compatible with high-density scaled CMOS for low power, portable electronics. In this paper, the SONOS memory cell erase cycle was investigated using a nonquasi-static (NQS) MOSFET model. Comparisons were made between the model predictions and experimental data.

  20. Cell-cycle radiation response: Role of intracellular factors

    Science.gov (United States)

    Blakely, E.; Chang, P.; Lommel, L.; Bjornstad, K.; Dixon, M.; Tobias, C.; Kumar, K.; Blakely, W. F.

    We have been studying variations of radiosensitivity and endogenous cellular factors during the course of progression through the human and hamster cell cycle. After exposure to low-LET radiations, the most radiosensitive cell stages are mitosis and the G1/S interface. The increased activity of a specific antioxidant enzyme such as superoxide dismutase in G1-phase, and the variations of endogenous thiols during cell division are thought to be intracellular factors of importance to the radiation survival response. These factors may contribute to modifying the age-dependent yield of lesions or more likely, to the efficiency of the repair processes. These molecular factors have been implicated in our cellular measurements of the larger values for the radiobiological oxygen effect late in the cycle compared to earlier cell ages. Low-LET radiation also delays progression through S phase which may allow more time for repair and hence contribute to radioresistance in late-S-phase. The cytoplasmic and intranuclear milieu of the cell appears to have less significant effects on lesions produced by high-LET radiation compared to those made by low-LET radiation. High-LET radiation fails to slow progression through S phase, and there is much less repair of lesions evident at all cell ages; however, high-LET particles cause a more profound block in G2 phase than that observed after low-LET radiation. Hazards posed by the interaction of damage from sequential doses of radiations of different qualities have been evaluated and are shown to lead to a cell-cycle-dependent enhancement of radiobiological effects. A summary comparison of various cell-cycle-dependent endpoints measured with low-or high-LET radiations is given and includes a discussion of the possible additional effects introduced by microgravity.

  1. RL-10 Based Combined Cycle For A Small Reusable Single-Stage-To-Orbit Launcher

    Science.gov (United States)

    Balepin, Vladimir; Price, John; Filipenco, Victor

    1999-01-01

    This paper discusses a new application of the combined propulsion known as the KLIN(TM) cycle, consisting of a thermally integrated deeply cooled turbojet (DCTJ) and liquid rocket engine (LRE). If based on the RL10 rocket engine family, the KLIN (TM) cycle makes a small single-stage-to-orbit (SSTO) reusable launcher feasible and economically very attractive. Considered in this paper are the concept and parameters of a small SSTO reusable launch vehicle (RLV) powered by the KLIN (TM) cycle (sSSTO(TM)) launcher. Also discussed are the benefits of the small launcher, the reusability, and the combined cycle application. This paper shows the significant reduction of the gross take off weight (GTOW) and dry weight of the KLIN(TM) cycle-powered launcher compared to an all-rocket launcher.

  2. Cell cycle synchronization of canine ear fibroblasts for somatic cell nuclear transfer.

    Science.gov (United States)

    Koo, Ok Jae; Hossein, Mohammad Shamim; Hong, So Gun; Martinez-Conejero, Jose A; Lee, Byeong Chun

    2009-02-01

    Cycle synchronization of donor cells in the G0/G1 stage is a crucial step for successful somatic cell nuclear transfer. In the present report, we evaluated the effects of contact inhibition, serum starvation and the reagents - dimethyl sulphoxide (DMSO), roscovitine and cycloheximide (CHX) - on synchronization of canine fibroblasts at the G0/G1 stage. Ear fibroblast cells were collected from a beagle dog, placed into culture and used for analysis at passages three to eight. The population doubling time was 36.5 h. The proportion of G0/G1 cells was significantly increased by contact inhibition (77.1%) as compared with cycling cells (70.1%); however, extending the duration of culture did not induce further synchronization. After 24 h of serum starvation, cells were effectively synchronized at G0/G1 (77.1%). Although synchronization was further increased gradually after 24 h and even showed significant difference after 72 h (82.8%) of starvation, the proportion of dead cells also significantly increased after 24 h. The percentage of cells at the G0/G1 phase was increased (as compared with controls) after 72 h treatment with DMSO (76.1%) and after 48 h treatment with CHX (73.0%) or roscovitine (72.5%). However, the rate of cell death was increased after 24 and 72 h of treatment with DMSO and CHX, respectively. Thus, we recommend the use of roscovitine for cell cycle synchronization of canine ear fibroblasts as a preparatory step for SCNT.

  3. Cell cycle regulation of hematopoietic stem or progenitor cells.

    Science.gov (United States)

    Hao, Sha; Chen, Chen; Cheng, Tao

    2016-05-01

    The highly regulated process of blood production is achieved through the hierarchical organization of hematopoietic stem cell (HSC) subsets and their progenies, which differ in self-renewal and differentiation potential. Genetic studies in mice have demonstrated that cell cycle is tightly controlled by the complex interplay between extrinsic cues and intrinsic regulatory pathways involved in HSC self-renewal and differentiation. Deregulation of these cellular programs may transform HSCs or hematopoietic progenitor cells (HPCs) into disease-initiating stem cells, and can result in hematopoietic malignancies such as leukemia. While previous studies have shown roles for some cell cycle regulators and related signaling pathways in HSCs and HPCs, a more complete picture regarding the molecular mechanisms underlying cell cycle regulation in HSCs or HPCs is lacking. Based on accumulated studies in this field, the present review introduces the basic components of the cell cycle machinery and discusses their major cellular networks that regulate the dormancy and cell cycle progression of HSCs. Knowledge on this topic would help researchers and clinicians to better understand the pathogenesis of relevant blood disorders and to develop new strategies for therapeutic manipulation of HSCs.

  4. Evaluating Managerial Styles for System Development Life Cycle Stages to Ensure Software Project Success

    Science.gov (United States)

    Kocherla, Showry

    2012-01-01

    Information technology (IT) projects are considered successful if they are completed on time, within budget, and within scope. Even though, the required tools and methodologies are in place, IT projects continue to fail at a higher rate. Current literature lacks explanation for success within the stages of system development life-cycle (SDLC) such…

  5. Evaluation of Uncertainty on the Stages of Business Cycle: Implementation of Quantum Principles

    Directory of Open Access Journals (Sweden)

    Anna Svirina

    2014-08-01

    Full Text Available The goal of the research is to propose implementation of quantum principles for evaluation of economic development on stages of business cycle, define the difference between traditional (deterministic and quantum approaches and to provide quantitative analysis based argumentation for use of quantum economic principles in evaluation of internal and external factors on the stages of business cycle. The object of the study is possibility and reliability of quantum economic principles implementation to evaluate economic system performance. The authors analyze existing approaches towards implementation of deterministic, probabilistic and quantum models for estimating internal and external factors on stages of business cycle, define the benchmark for shift from traditional economy models and principles to quantum principles, describe the stages of business cycle from the quantum economics point of view and provide quantitative analysis of deterministic and quantum models quality on the level of enterprise to prove efficiency and reliability of quantum principles based approach. Calculations and data processing were carried out using Microsoft Excel and SSPS Statistics software.

  6. Cell cycle regulation in human embryonic stem cells: links to adaptation to cell culture.

    Science.gov (United States)

    Barta, Tomas; Dolezalova, Dasa; Holubcova, Zuzana; Hampl, Ales

    2013-03-01

    Cell cycle represents not only a tightly orchestrated mechanism of cell replication and cell division but it also plays an important role in regulation of cell fate decision. Particularly in the context of pluripotent stem cells or multipotent progenitor cells, regulation of cell fate decision is of paramount importance. It has been shown that human embryonic stem cells (hESCs) show unique cell cycle characteristics, such as short doubling time due to abbreviated G1 phase; these properties change with the onset of differentiation. This review summarizes the current understanding of cell cycle regulation in hESCs. We discuss cell cycle properties as well as regulatory machinery governing cell cycle progression of undifferentiated hESCs. Additionally, we provide evidence that long-term culture of hESCs is accompanied by changes in cell cycle properties as well as configuration of several cell cycle regulatory molecules.

  7. A thermodynamic cycle for the solar cell

    Science.gov (United States)

    Alicki, Robert; Gelbwaser-Klimovsky, David; Jenkins, Alejandro

    2017-03-01

    A solar cell is a heat engine, but textbook treatments are not wholly satisfactory from a thermodynamic standpoint, since they present solar cells as directly converting the energy of light into electricity, and the current in the circuit as maintained by an electrostatic potential. We propose a thermodynamic cycle in which the gas of electrons in the p phase serves as the working substance. The interface between the p and n phases acts as a self-oscillating piston that modulates the absorption of heat from the photons so that it may perform a net positive work during a complete cycle of its motion, in accordance with the laws of thermodynamics. We draw a simple hydrodynamical analogy between this model and the ;putt-putt; engine of toy boats, in which the interface between the water's liquid and gas phases serves as the piston. We point out some testable consequences of this model.

  8. Mechanisms of cell cycle control revealed by a systematic and quantitative overexpression screen in S. cerevisiae.

    Directory of Open Access Journals (Sweden)

    Wei Niu

    2008-07-01

    Full Text Available Regulation of cell cycle progression is fundamental to cell health and reproduction, and failures in this process are associated with many human diseases. Much of our knowledge of cell cycle regulators derives from loss-of-function studies. To reveal new cell cycle regulatory genes that are difficult to identify in loss-of-function studies, we performed a near-genome-wide flow cytometry assay of yeast gene overexpression-induced cell cycle delay phenotypes. We identified 108 genes whose overexpression significantly delayed the progression of the yeast cell cycle at a specific stage. Many of the genes are newly implicated in cell cycle progression, for example SKO1, RFA1, and YPR015C. The overexpression of RFA1 or YPR015C delayed the cell cycle at G2/M phases by disrupting spindle attachment to chromosomes and activating the DNA damage checkpoint, respectively. In contrast, overexpression of the transcription factor SKO1 arrests cells at G1 phase by activating the pheromone response pathway, revealing new cross-talk between osmotic sensing and mating. More generally, 92%-94% of the genes exhibit distinct phenotypes when overexpressed as compared to their corresponding deletion mutants, supporting the notion that many genes may gain functions upon overexpression. This work thus implicates new genes in cell cycle progression, complements previous screens, and lays the foundation for future experiments to define more precisely roles for these genes in cell cycle progression.

  9. 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.

  10. Targeting cell cycle regulators in hematologic malignancies

    Directory of Open Access Journals (Sweden)

    Eiman eAleem

    2015-04-01

    Full Text Available Hematologic malignancies represent the fourth most frequently diagnosed cancer in economically developed countries. In hematologic malignancies normal hematopoiesis is interrupted by uncontrolled growth of a genetically altered stem or progenitor cell (HSPC that maintains its ability of self-renewal. Cyclin-dependent kinases (CDKs not only regulate the mammalian cell cycle, but also influence other vital cellular processes, such as stem cell renewal, differentiation, transcription, epigenetic regulation, apoptosis, and DNA repair. Chromosomal translocations, amplification, overexpression and altered CDK activities have been described in different types of human cancer, which have made them attractive targets for pharmacological inhibition. Mouse models deficient for one or more CDKs have significantly contributed to our current understanding of the physiological functions of CDKs, as well as their roles in human cancer. The present review focuses on selected cell cycle kinases with recent emerging key functions in hematopoiesis and in hematopoietic malignancies, such as CDK6 and its role in MLL-rearranged leukemia and acute lymphocytic leukemia, CDK1 and its regulator WEE-1 in acute myeloid leukemia, and cyclin C/CDK8/CDK19 complexes in T-cell acute lymphocytic leukemia. The knowledge gained from gene knockout experiments in mice of these kinases is also summarized. An overview of compounds targeting these kinases, which are currently in clinical development in various solid tumors and hematopoietic malignances, is presented. These include the CDK4/CDK6 inhibitors (palbociclib, LEE011, LY2835219, pan-CDK inhibitors that target CDK1 (dinaciclib, flavopiridol, AT7519, TG02, P276-00, terampeprocol and RGB 286638 as well as the WEE-1 kinase inhibitor, MK-1775. The advantage of combination therapy of cell cycle inhibitors with conventional chemotherapeutic agents used in the treatment of AML, such as cytarabine, is discussed.

  11. Extended Culture of Early Stage Embryos in Frozen-thawed Cycles

    Institute of Scientific and Technical Information of China (English)

    Hong-bo WANG; Yan-hui LI

    2009-01-01

    Objective To investigate the impact of extended culture of early stage embryos on pregnancy outcome of frozen embryo transfer (FET).Methods The survival rates of embryos after thawing and pregnancy outcome following FET were compared retrospectively between zygote and cleavage embryos which cultured to cleavage stage or extended cultured to blastocysts. Results A total of 425 zygote embryos in 67 cycles were thawed. After thawing, the survival rate was 94.4% and with an average transfer of 2.8 embryos, the clinical pregnancy rate was 55.2% (37/67). In 222 FET cycles, totally 1 270 cleavage stage embryos were thawed and the overall survival rates were 80.3%. With an average transfer of 2.7 embryos, the clinical pregnancy rate was 55.4% (123/222). A significantly lower percentage of degenerated embryos were found for zygotes (5.6%) than that for cleavage stage embryos (19.7%) (P0.05). Conclusion Although the clinical pregnancy rate was not different between patients with freeze-thaw zygote and cleavage stage embryo transfer, higher survival rate for zygote was shown compared with that for cleavage stage embryo. However, the present studies did not demonstrate that extended culture thawing embryos to blastocyst could achieve favor clinical outcome.

  12. Changes of the cell cycle regulators and cell cycle arrest in cervical cancer cells after cisplatin therapy

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Objective To investigate the changes of the cell cycle regulators ATM,Chk2 and p53 and cell cycle arrest in HeLa cells after cisplatin therapy. Methods The proliferation-inhibiting rates of HeLa cells induced by cisplatin of different concentrations were measured by MTT assays. The mRNA and protein expressions of ATM,Chk2 and p53 of HeLa cells with and without cisplatin were detected by RT-PCR and Western blot,respectively. The cell cycle analysis was conducted by flow cytometric analysis. Results Cisplatin...

  13. Complex scheme of company image management on the stages of its life cycle

    Directory of Open Access Journals (Sweden)

    A.V. Kolodka

    2014-03-01

    Full Text Available The aim of the article. The aim of the article is to create a common integrated circuit image management during a life-cycle of enterprise based on internal and external economic conditions. The results of the analysis. In the article the general scheme of image management during a life-cycle of enterprise based on internal and external economic conditions is formed. There is no single view on the question of forming general concepts and approaches to image building. That threatens making the correct management actions in developing and strengthening the image by top professionals. In the article several tasks were accomplished for achieving the main goal. The basic concepts of formation and management of the company image are analyzed. According to this the main tasks of image policy on company life-cycle, the activities on the formation of internal and external image were defined. The approaches of the formation and company image management are analyzed. The features and the necessity of using different approaches to image management at each stage of the company life cycle are highlighted. Research results of modern approaches to the company image formation serve the goals of reconstruction a coherent picture of this management problem were developed. The author proved that measures for formation and management of company image should be based on the analysis of existing conditions of its image and stages of its life cycle, which will increase the efficiency of management. Conclusions and directions of further researches. Completed the system analysis of the concepts and approaches to the formation and the company image management, revealed their strengths and weaknesses. The conceptual scheme of the purposeful control of company image on the stages of its life cycle was developed. Recommendations how to use the approaches to manage company image on its life-cycle were proposed.The results obtained allow forming the image policy, which is

  14. Stages and duration of the cycle of the seminiferous epithelium in oncilla (Leopardus tigrinus, Schreber, 1775).

    Science.gov (United States)

    Balarini, Maytê Koch; de Paula, Tarcízio Antônio Rego; da Matta, S L Pinto; Peixoto, J Vogas; Guião-Leite, F Lima; Rossi Júnior, J L; Czermak Junior, A C; Walker, N J

    2012-03-15

    Six adult Leopardus tigrinus (oncilla) were studied to characterize stages of the seminiferous epithelium cycle and its relative frequency and duration, as well as morphometric parameters of the testes. Testicular fragments were obtained (incisional biopsy), embedded (glycol methacrylate), and histologic sections examined with light microscopy. The cycle of the seminiferous epithelium was categorized into eight stages (based on the tubular morphology method). The duration of one seminiferous epithelium cycle was 9.19 d, and approximately 41.37 d were required for development of sperm from spermatogonia. On average, diameter of the seminiferous tubules was 228.29 μm, epithelium height was 78.86 μm, and there were 16.99 m of testicular tubules per gram of testis. Body weight averaged 2.589 kg, of which 0.06 and 0.04% were attributed to the testis and seminiferous tubules, respectively. In conclusion, there were eight distinct stages in the seminiferous epithelium, the length of the seminiferous epithelium cycle was close to that in domestic cats and cougars, and testicular and somatic indexes were similar to those of other carnivores of similar size.

  15. Does thermal variability experienced at the egg stage influence life history traits across life cycle stages in a small invertebrate?

    Directory of Open Access Journals (Sweden)

    Kun Xing

    Full Text Available Although effects of thermal stability on eggs have often been considered in vertebrates, there is little data thermal stability in insect eggs even though these eggs are often exposed in nature to widely fluctuating ambient conditions. The modularity of development in invertebrates might lead to compensation across life cycle stages but this remains to be tested particularly within the context of realistic temperature fluctuations encountered in nature. We simulated natural temperate fluctuations on eggs of the worldwide cruciferous insect pest, the diamondback moth (DBM, Plutella xylostella (L., while maintaining the same mean temperature (25°C±0°C, 25±4°C, 25±6°C, 25±8°C, 25±10°C, 25±12°C and assessed egg development, survival and life history traits across developmental stages. Moderate fluctuations (25±4°C, 25±6°C did not influence performance compared to the constant temperature treatment, and none of the treatments influenced egg survival. However the wide fluctuating temperatures (25±10°C, 25±12°C slowed development time and led to an increase in pre-pupal mass, although these changes did not translate into any effects on longevity or fecundity at the adult stage. These findings indicate that environmental effects can extend across developmental stages despite the modularity of moth development but also highlight that there are few fitness consequences of the most variable thermal conditions likely to be experienced by Plutella xylostella.

  16. Managing of economic potential of the enterprise at different stages of its life cycle

    Directory of Open Access Journals (Sweden)

    O.I. Maslak

    2014-03-01

    reserves its potential. The fluctuations of the environment and the corresponding internal characteristics of enterprises form the stage of the business cycle, in which the processes of formation, development and utilization potentialare occur. At the same time, management capacity should be in the light of these stages of the life cycle that aims to provide adaptability and efficiency of the company. Thus, an urgent task today is to organize management processes and economic potential businesses considering climate stages of its life cycle. In the life cycle climate offer the sum of the intrinsic characteristics on some stage considering of the environmental factors that have a significant impact on the entity. In the article the main priority areas of capacity on each stage of the life cycle and ways to implement them were suggested. At each stage of the life cycle program of strategic development and program activities are allocated. In this first group are more far-reaching programs for the long term, they aim to develop the existing activities of the company in the future, expand markets and gain leadership in the field of actual entities. Applications of the second group are designed for a short term, their goal is to maximize income at current economic conditions. The choice of such programs or shows a desire guidance in the near future to change the profile of the company, access to new products or insolvency of the entity the further development in this area of activity. The choice of a development program depends on the stage of the life cycle of an enterprise, hidden reserve capacity and ability of the company to quickly activate. Conclusions and directions of further researches. Thus, the constant fluctuation of the environment necessitate the development of control mechanisms that would provide an opportunity to identify and activate reserves passive potential for successful implementation of enterprise development programs, priority in climate certain stages

  17. The cell cycle rallies the transcription cycle: Cdc28/Cdk1 is a cell cycle-regulated transcriptional CDK.

    Science.gov (United States)

    Chymkowitch, Pierre; Enserink, Jorrit M

    2013-01-01

    In the budding yeast Saccharomyces cerevisiae, the cyclin-dependent kinases (CDKs) Kin28, Bur1 and Ctk1 regulate basal transcription by phosphorylating the carboxyl-terminal domain (CTD) of RNA polymerase II. However, very little is known about the involvement of the cell cycle CDK Cdc28 in the transcription process. We have recently shown that, upon cell cycle entry, Cdc28 kinase activity boosts transcription of a subset of genes by directly stimulating the basal transcription machinery. Here, we discuss the biological significance of this finding and give our view of the kinase-dependent role of Cdc28 in regulation of RNA polymerase II.

  18. Hormone-dependence of sarin lethality in rats: Sex differences and stage of the estrous cycle

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Carl D., E-mail: carl.d.smith179.mil@mail.mil; Wright, Linnzi K.M.; Garcia, Gregory E.; Lee, Robyn B.; Lumley, Lucille A.

    2015-09-15

    Chemical warfare nerve agents (CWNAs) are highly toxic compounds that cause a cascade of symptoms and death, if exposed casualties are left untreated. Numerous rodent models have investigated the toxicity and mechanisms of toxicity of CWNAs, but most are limited to male subjects. Given the profound physiological effects of circulating gonadal hormones in female rodents, it is possible that the daily cyclical fluctuations of these hormones affect females' sensitivity to the lethal effects of CWNAs, and previous reports that included female subjects did not control for the stage of the hormonal cycle. The aim of the current study was to determine the 24-hour median lethal dose (LD{sub 50}) of the CWNA sarin in male, ovariectomized (OVEX) female, and female rats during different stages of the estrous cycle (diestrus, proestrus, and estrus). Additionally, baseline activity levels of plasma acetylcholinesterase, butyrylcholinesterase, and carboxylesterase were measured to determine differences among the groups. Results indicated that females in proestrus had a significantly higher LD{sub 50} of sarin compared to OVEX and estrous females. Although some sex differences were observed in the activity levels of plasma esterases, they were not consistent and likely not large enough to significantly affect the LD{sub 50}s. These results suggest that hormonal cyclicity can influence the outcome of CWNA-related studies using female rodents, and that this variability can be minimized by controlling for the stage of the cycle. Additional research is necessary to determine the precise mechanism of the observed differences because it is unlikely to be solely explained by plasma esterase activity. - Highlights: • The LD{sub 50} of sarin was determined in female rats throughout the stages of the estrous cycle. • Females in proestrus had a significantly higher LD{sub 50} compared to estrous or ovariectomized females. • No sex differences were observed between male and female

  19. The cell-cycle state of stem cells determines cell fate propensity.

    Science.gov (United States)

    Pauklin, Siim; Vallier, Ludovic

    2013-09-26

    Self-renewal and differentiation of stem cells are fundamentally associated with cell-cycle progression to enable tissue specification, organ homeostasis, and potentially tumorigenesis. However, technical challenges have impaired the study of the molecular interactions coordinating cell fate choice and cell-cycle progression. Here, we bypass these limitations by using the FUCCI reporter system in human pluripotent stem cells and show that their capacity of differentiation varies during the progression of their cell cycle. These mechanisms are governed by the cell-cycle regulators cyclin D1-3 that control differentiation signals such as the TGF-β-Smad2/3 pathway. Conversely, cell-cycle manipulation using a small molecule directs differentiation of hPSCs and provides an approach to generate cell types with a clinical interest. Our results demonstrate that cell fate decisions are tightly associated with the cell-cycle machinery and reveal insights in the mechanisms synchronizing differentiation and proliferation in developing tissues.

  20. [CHROMATIN ORGANIZATION IN CELL CYCLE OF AMOEBA PROTEUS ACCORDING TO OPTICAL TOMOGRAPHY DATA].

    Science.gov (United States)

    Demin, S Yu; Berdieva, M A; Podlipaeva, Yu I; Yudin, A L; Goodkov, A V

    2015-01-01

    For the first time the nuclear cycle of large freshwater amoeba Amoeba proteus was studied by the method of optical tomography. The nuclei were fixed in situ in the cells of synchronized culture, stained by DAPI and examined by confocal laser scanning microscope. 3D-images of intranuclear chromatin were studied in details at different stages of nuclear cycle. The obtained data, together with literary ones allow represent the dynamics of structural organization of the nucleus in Amoeba proteus cell cycle in a new fashion. It was concluded that in this species the two-stage interphase takes place, as well as mitosis of peculiar type which does not correspond to any known type of mitosis according to classification existing now. It is presumed that in the course of nuclear cycle the chromosomes and/or their fragments are amplified, this presumption being in a good correspondence with the data about nuclear DNA hyperreplication in the cell cycle of A. proteus. As a result of chromosomes amplification their number may vary at different stages of cell cycle, and it allows to explain the contradictory data concerning the exact number of chromosomes in this species. The elimination of extra-DNA occurs mainly at the stage between prophase and prometaphase. We presume the majority of chromosomes, or may be even all of them to be referred to cholocentric type according to their behaviour during the mitosis.

  1. The Life Cycle Completed. Extended Version with New Chapters on the Ninth Stage of Development by Joan M. Erikson.

    Science.gov (United States)

    Erikson, Erik H.

    This expanded edition of a 1982 book by Erik Erikson summarizes his work on the stages of the human life cycle, including chapters on psychosexuality and the cycle of generations, major stages in psychosocial development, and ego and ethos. An additional chapter on the ninth stage sets forth his philosophy on old age--i.e. the 80s and 90s--and how…

  2. Cisplatin, Radiation Therapy, and Pembrolizumab in Treating Patients With Stage III-IV Head and Neck Squamous Cell Carcinoma

    Science.gov (United States)

    2016-05-16

    Stage III Hypopharyngeal Squamous Cell Carcinoma; Stage III Laryngeal Squamous Cell Carcinoma; Stage III Oral Cavity Squamous Cell Carcinoma; Stage III Oropharyngeal Squamous Cell Carcinoma; Stage IVA Hypopharyngeal Squamous Cell Carcinoma; Stage IVA Laryngeal Squamous Cell Carcinoma; Stage IVA Oral Cavity Squamous Cell Carcinoma; Stage IVA Oropharyngeal Squamous Cell Carcinoma; Stage IVB Hypopharyngeal Squamous Cell Carcinoma; Stage IVB Laryngeal Squamous Cell Carcinoma; Stage IVB Oral Cavity Squamous Cell Carcinoma; Stage IVB Oropharyngeal Squamous Cell Carcinoma

  3. Life-cycle analysis of product integrated polymer solar cells

    DEFF Research Database (Denmark)

    Espinosa Martinez, Nieves; García-Valverde, Rafael; Krebs, Frederik C

    2011-01-01

    economics through design to functionality. An LCA study was performed to quantify the energy use and greenhouse gas (GHG) emissions from electricity use in the manufacture of a light-weight lamp based on a plastic foil, a lithium-polymer battery, a polymer solar cell, printed circuitry, blocking diode......A life cycle analysis (LCA) on a product integrated polymer solar module is carried out in this study. These assessments are well-known to be useful in developmental stages of a product in order to identify the bottlenecks for the up-scaling in its production phase for several aspects spanning from...... on the complete product integrated polymer solar cell. We have compared this portable lighting system with other lighting solutions, namely: a kerosene lamp in a remote rural area in Africa (Ethiopia), as a replacement of a silicon PV based lamp, in place of a torch with non-rechargeable lead-acid battery...

  4. Activation of the ribosomal RNA genes late in the third cell cycle of porcine embryos

    DEFF Research Database (Denmark)

    Viuff, Dorthe; Greve, Torben; Holm, Peter

    2002-01-01

    In porcine embryos, nucleoli are first observed during the third postfertilization cell cycle, i.e., at the 4-cell stage. However, direct studies of the initiation of rRNA transcription have not been reported. This transcription was investigated in the present study by simultaneous visualization...... the third cell cycle....... electron microscopy. In general, the 2-cell and 4-cell embryos fixed at 10 and 20 h postcleavage (hpc) showed no signs of rRNA transcription. Four small clusters of fluorescein isothiocyanate (FITC) labeling were visible in interphase nuclei, consistent with hybridization to the rRNA gene clusters only...

  5. Capacity fade of Sony 18650 cells cycled at elevated temperatures. Part I. Cycling performance

    Science.gov (United States)

    Ramadass, P.; Haran, Bala; White, Ralph; Popov, Branko N.

    The capacity fade of Sony 18650 Li-ion cells increases with increase in temperature. After 800 cycles, the cells cycled at RT and 45 °C showed a capacity fade of 30 and 36%, respectively. The cell cycled at 55 °C showed a capacity loss of about 70% after 490 cycles. The rate capability of the cells continues to decrease with cycling. Impedance measurements showed an overall increase in the cell resistance with cycling and temperature. Impedance studies of the electrode materials showed an increased positive electrode resistance when compared to that of the negative electrode for cells cycled at RT and 45 °C. However, cells cycled at 50 and 55 °C exhibit higher negative electrode resistance. The increased capacity fade for the cells cycled at high temperatures can be explained by taking into account the repeated film formation over the surface of anode, which results in increased rate of lithium loss and also in a drastic increase in the negative electrode resistance with cycling.

  6. P27 in cell cycle control and cancer

    DEFF Research Database (Denmark)

    Møller, Michael Boe

    2000-01-01

    In order to survive, cells need tight control of cell cycle progression. The control mechanisms are often lost in human cancer cells. The cell cycle is driven forward by cyclin-dependent kinases (CDKs). The CDK inhibitors (CKIs) are important regulators of the CDKs. As the name implies, CKIs were...

  7. Nuclear reprogramming: kinetics of cell cycle and metabolic progression as determinants of success.

    Directory of Open Access Journals (Sweden)

    Sebastian Thomas Balbach

    Full Text Available Establishment of totipotency after somatic cell nuclear transfer (NT requires not only reprogramming of gene expression, but also conversion of the cell cycle from quiescence to the precisely timed sequence of embryonic cleavage. Inadequate adaptation of the somatic nucleus to the embryonic cell cycle regime may lay the foundation for NT embryo failure and their reported lower cell counts. We combined bright field and fluorescence imaging of histone H(2b-GFP expressing mouse embryos, to record cell divisions up to the blastocyst stage. This allowed us to quantitatively analyze cleavage kinetics of cloned embryos and revealed an extended and inconstant duration of the second and third cell cycles compared to fertilized controls generated by intracytoplasmic sperm injection (ICSI. Compared to fertilized embryos, slow and fast cleaving NT embryos presented similar rates of errors in M phase, but were considerably less tolerant to mitotic errors and underwent cleavage arrest. Although NT embryos vary substantially in their speed of cell cycle progression, transcriptome analysis did not detect systematic differences between fast and slow NT embryos. Profiling of amino acid turnover during pre-implantation development revealed that NT embryos consume lower amounts of amino acids, in particular arginine, than fertilized embryos until morula stage. An increased arginine supplementation enhanced development to blastocyst and increased embryo cell numbers. We conclude that a cell cycle delay, which is independent of pluripotency marker reactivation, and metabolic restraints reduce cell counts of NT embryos and impede their development.

  8. Test sequencing problem arising at the design stage for reducing life cycle cost

    Institute of Scientific and Technical Information of China (English)

    Zhang Shigang; Hu Zheng; Wen Xisen

    2013-01-01

    Previous test sequencing algorithms only consider the execution cost of a test at the application stage.Due to the fact that the placement cost of some tests at the design stage is considerably high compared with the execution cost,the sequential diagnosis strategy obtained by previous methods is actually not optimal from the view of life cycle.In this paper,the test sequencing problem based on life cycle cost is presented.It is formulated as an optimization problem,which is non-deterministic polynomial-time hard (NP-hard).An algorithm and a strategy to improve its computational efficiency are proposed.The formulation and algorithms are tested on various simulated systems and comparisons are made with the extant test sequencing methods.Application on a pump rotational speed control (PRSC) system of a spacecraft is studied in detail.Both the simulation results and the real-world case application results suggest that the solution proposed in this paper can significantly reduce the life cycle cost of a sequential fault diagnosis strategy.

  9. The significance of crack initiation stage in very high cycle fatigue of steels

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, J. [Department of Materials Engineering, Karlstad University (Sweden); Burman, C.; Kazymyrovych, V.

    2010-04-15

    Different stages of the Very High Cycle Fatigue (VHCF) crack evolution in tool steels have been explored using a 20 kHz ultrasonic fatigue testing equipment. Extensive experimental data is presented describing VHCF behaviour, strength and crack initiating defects in an AISI H11 tool steel. Striation measurements are used to estimate fatigue crack growth rate, between 10{sup -8} and 10{sup -6} m/cycle, and the number of load cycles required for a crack to grow to critical dimensions. The growth of small fatigue cracks within the ''fish-eye'' is shown to be distinctively different from the crack propagation behaviour of larger cracks. More importantly, the crack initiation stage is shown to determine the total fatigue life, which emphasizes the inherent difficulty to detect VHCF cracks prior to failure. Several mechanisms for initiation and early crack growth are possible. Some of them are discussed here: crack development by local accumulation of fatigue damage at the inclusion - matrix interface, hydrogen assisted crack growth and crack initiation by decohesion of carbides from the matrix. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  10. Local circadian clock gates cell cycle progression of transient amplifying cells during regenerative hair cycling.

    Science.gov (United States)

    Plikus, Maksim V; Vollmers, Christopher; de la Cruz, Damon; Chaix, Amandine; Ramos, Raul; Panda, Satchidananda; Chuong, Cheng-Ming

    2013-06-04

    Regenerative cycling of hair follicles offers an unique opportunity to explore the role of circadian clock in physiological tissue regeneration. We focused on the role of circadian clock in actively proliferating transient amplifying cells, as opposed to quiescent stem cells. We identified two key sites of peripheral circadian clock activity specific to regenerating anagen hair follicles, namely epithelial matrix and mesenchymal dermal papilla. We showed that peripheral circadian clock in epithelial matrix cells generates prominent daily mitotic rhythm. As a consequence of this mitotic rhythmicity, hairs grow faster in the morning than in the evening. Because cells are the most susceptible to DNA damage during mitosis, this cycle leads to a remarkable time-of-day-dependent sensitivity of growing hair follicles to genotoxic stress. Same doses of γ-radiation caused dramatic hair loss in wild-type mice when administered in the morning, during mitotic peak, compared with the evening, when hair loss is minimal. This diurnal radioprotective effect becomes lost in circadian mutants, consistent with asynchronous mitoses in their hair follicles. Clock coordinates cell cycle progression with genotoxic stress responses by synchronizing Cdc2/Cyclin B-mediated G2/M checkpoint. Our results uncover diurnal mitotic gating as the essential protective mechanism in highly proliferative hair follicles and offer strategies for minimizing or maximizing cytotoxicity of radiation therapies.

  11. Stages of Small Cell Lung Cancer

    Science.gov (United States)

    ... lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung. The ... diagnosed, tests are done to find out if cancer cells have spread within the chest or to other ...

  12. Treatment Options by Stage (Merkel Cell Carcinoma)

    Science.gov (United States)

    ... Cancer Skin Cancer Screening Research Merkel Cell Carcinoma Treatment (PDQ®)–Patient Version General Information About Merkel Cell ... Certain factors affect prognosis (chance of recovery) and treatment options. The prognosis (chance of recovery ) and treatment ...

  13. Cell Cycle Phase Abnormalities Do Not Account for Disordered Proliferation in Barrett's Carcinogenesis

    Directory of Open Access Journals (Sweden)

    Pierre Lao-Sirieix

    2004-11-01

    Full Text Available Barrett's esophagus (BE epithelium is the precursor lesion for esophageal adenocarcinoma. Cell cycle proteins have been advocated as biomarkers to predict the malignant potential in BE. However, whether disruption of the cell cycle plays a causal role in Barrett's carcinogenesis is not clear. Specimens from the Barrett's dysplasia—carcinoma sequence were immunostained for cell cycle phase markers (cyclin D1 for G1; cyclin A for S, G2, and M; cytoplasmic cyclin B1 for G2; and phosphorylated histone 3 for M phase and expressed as a proportion of proliferating cells. Flow cytometric analysis of the cell cycle phase of prospective biopsies was also performed. The proliferation status of nondysplastic BE was similar to gastric antrum and D2, but the proliferative compartment extended to the luminal surface. In dysplastic samples, the number of proliferating cells correlated with the degree of dysplasia (P < .001. The overall levels of cyclins A and B1 correlated with the degree of dysplasia (P < .001. However, the cell cycle phase distribution measured with both immunostaining and flow cytometry was conserved during all stages of BE, dysplasia, and cancer. Hence, the increased proliferation seen in Barrett's carcinogenesis is due to abnormal cell cycle entry or exit, rather than a primary abnormality within the cell cycle.

  14. Cell-cycle times and the tumour control probability.

    Science.gov (United States)

    Maler, Adrian; Lutscher, Frithjof

    2010-12-01

    Mechanistic dynamic cell population models for the tumour control probability (TCP) to date have used a simplistic representation of the cell cycle: either an exponential cell-cycle time distribution (Zaider & Minerbo, 2000, Tumour control probability: a formulation applicable to any temporal protocol of dose delivery. Phys. Med. Biol., 45, 279-293) or a two-compartment model (Dawson & Hillen, 2006, Derivation of the tumour control probability (TCP) from a cell cycle model. Comput. Math. Methods Med., 7, 121-142; Hillen, de Vries, Gong & Yurtseven, 2009, From cell population models to tumour control probability: including cell cycle effects. Acta Oncol. (submitted)). Neither of these simplifications captures realistic cell-cycle time distributions, which are rather narrowly peaked around the mean. We investigate how including such distributions affects predictions of the TCP. At first, we revisit the so-called 'active-quiescent' model that splits the cell cycle into two compartments and explore how an assumption of compartmental independence influences the predicted TCP. Then, we formulate a deterministic age-structured model and a corresponding branching process. We find that under realistic cell-cycle time distributions, lower treatment intensities are sufficient to obtain the same TCP as in the aforementioned models with simplified cell cycles, as long as the treatment is constant in time. For fractionated treatment, the situation reverses such that under realistic cell-cycle time distributions, the model requires more intense treatment to obtain the same TCP.

  15. THE EFFICIENCY OF PROMOTIONAL INSTRUMENTS RELATED TO THE PRODUCT LIFE CYCLE STAGES

    Directory of Open Access Journals (Sweden)

    MIHAELA MARCU

    2010-01-01

    Full Text Available Regarded as a planning tool, PLC (product life cycle strongly contributes to the identification of the main marketing challenges that may arise throughout the life of a product/service. Thus, the marketing management has the opportunity to develop and implement those solutions designed to optimize each of the 4P of marketing mix: product (quality, price, distribution (placement and promotion. The communication program has an essential role, because the company presents through it its "product" to actual or potential customers in order to convince them of the benefits of purchasing/using it. The efficiency of the promotional instruments involves an appropriate allocation of funds needed to promote the product/service in relation to the stage of its life cycle.

  16. Hormone-dependence of sarin lethality in rats: sex differences and stage of the estrous cycle

    Science.gov (United States)

    Smith, Carl D.; Wright, Linnzi K.M.; Garcia, Gregory E.; Lee, Robyn B.; Lumley, Lucille A.

    2015-01-01

    Chemical warfare nerve agents (CWNAs) are highly toxic compounds that cause a cascade of symptoms and death, if exposed casualties are left untreated. Numerous rodent models have investigated the toxicity and mechanisms of toxicity of CWNAs, but most are limited to male subjects. Given the profound physiological effects of circulating gonadal hormones in female rodents, it is possible that the daily cyclical fluctuations of these hormones affect females’ sensitivity to the lethal effects of CWNAs, and previous reports that included female subjects did not control for the stage of the hormonal cycle. The aim of the current study was to determine the 24-hour median lethal dose (LD50) of the CWNA sarin in male, ovariectomized (OVEX) female, and female rats during different stages of the estrous cycle (diestrus, proestrus, and estrus). Additionally, baseline activity levels of plasma acetylcholinesterase, butyrylcholinesterase, and carboxylesterase were measured to determine differences among the groups. Results indicated that females in proestrus had a significantly higher LD50 of sarin compared to OVEX and estrous females. Although some sex differences were observed in the activity levels of plasma esterases, they were not consistent and likely not large enough to significantly affect the LD50s. These results suggest that hormonal cyclicity can influence the outcome of CWNA-related studies using female rodents, and that this variability can be minimized by controlling for the stage of the cycle. Additional research is necessary to determine the precise mechanism of the observed differences because it is unlikely to be solely explained by plasma esterase activity. PMID:26079828

  17. Breast cancer cell behaviors on staged tumorigenesis-mimicking matrices derived from tumor cells at various malignant stages.

    Science.gov (United States)

    Hoshiba, Takashi; Tanaka, Masaru

    2013-09-20

    Extracellular matrix (ECM) has been focused to understand tumor progression in addition to the genetic mutation of cancer cells. Here, we prepared "staged tumorigenesis-mimicking matrices" which mimic in vivo ECM in tumor tissue at each malignant stage to understand the roles of ECM in tumor progression. Breast tumor cells, MDA-MB-231 (invasive), MCF-7 (non-invasive), and MCF-10A (benign) cells, were cultured to form their own ECM beneath the cells and formed ECM was prepared as staged tumorigenesis-mimicking matrices by decellularization treatment. Cells showed weak attachment on the matrices derived from MDA-MB-231 cancer cells. The proliferations of MDA-MB-231 and MCF-7 was promoted on the matrices derived from MDA-MB-231 cancer cells whereas MCF-10A cell proliferation was not promoted. MCF-10A cell proliferation was promoted on the matrices derived from MCF-10A cells. Chemoresistance of MDA-MB-231 cells against 5-fluorouracil increased on only matrices derived from MDA-MB-231 cells. Our results showed that the cells showed different behaviors on staged tumorigenesis-mimicking matrices according to the malignancy of cell sources for ECM preparation. Therefore, staged tumorigenesis-mimicking matrices might be a useful in vitro ECM models to investigate the roles of ECM in tumor progression.

  18. Mitochondrial dynamics and the cell cycle

    Directory of Open Access Journals (Sweden)

    Penny M.A. Kianian

    2014-05-01

    Full Text Available Nuclear-mitochondrial (NM communication impacts many aspects of plant development including vigor, sterility and viability. Dynamic changes in mitochondrial number, shape, size, and cellular location takes place during the cell cycle possibly impacting the process itself and leading to distribution of this organelle into daughter cells. The genes that underlie these changes are beginning to be identified in model plants such as Arabidopsis. In animals disruption of the drp1 gene, a homolog to the plant drp3A and drp3B, delays mitochondrial division. This mutation results in increased aneuploidy due to chromosome mis-segregation. It remains to be discovered if a similar outcome is observed in plants. Alloplasmic lines provide an opportunity to understand the communication between the cytoplasmic organelles and the nucleus. Examples of studies in these lines, especially from the extensive collection in wheat, point to the role of mitochondria in chromosome movement, pollen fertility and other aspects of development. Genes involved in NM interaction also are believed to play a critical role in evolution of species and interspecific cross incompatibilities.

  19. Changes of the cell cycle regulators and cell cycle arrest in cervical cancer cells after cisplatin therapy

    Institute of Scientific and Technical Information of China (English)

    Ke-xiu Zhu; Ya-li Cao; Bin Li; Jia Wang; Xiao-bing Han

    2009-01-01

    Objective To investigate the changes of the cell cycle regulators ATM, Chk2 and p53 and cell cycle arrest in HeLa cells after cisplatin therapy. Methods The proliferation-inhibiting rates of HeLa cells induced by eisplatin of different concentrations were measured by MTT assays. The mRNA and protein expressions of ATM, Chk2 and p53 of HeLa cells with and withont cisplatin were detected by RT-PCR and Western blot, respectively. The cell cycle analysis was conducted by flow cytometric analysis. Results Cisplatin inhibited the proliferation of HeLa cells in a dose- and time-dependent manner. The mRNA and protein expressions of ATM, Chk2 and p53 were increased in HeLa cells treated with cisplatin. The cell cycle was arrested in G2/M phase in HeLa cells treated with cisplatin. Conclusion Activation of ATM, Chk2 and p53 might be critical in determining whether cells survive or undergo apoptesis. Targeting ATM, Chk2 and p53 pathway might he a promising strategy for reversing chemoresistance to clsplatin in cervical cancer.

  20. [The 4-stage continence-micturition cycle. The presentation of a urodynamic, diagnostic and therapeutic abacus].

    Science.gov (United States)

    Lardennois, B; Clément, T; Coulon, J M; Brandt, B

    1990-01-01

    The complexity of the mode of operation of the bladder and urinary sphincter has led to the development of a number of temporospatial physiologic models that divide the process of micturition into several stages in order to facilitate investigations. Ten years ago, the authors described a two-stage continence-micturition model intended to improve the accuracy of studies of urodynamic disorders and thus contribute to the development of more effective and more rational therapeutic solutions. A large number of diseases can affect the distal urinary tract and recent advances in neurophysiology [10] have made the selection of the appropriate therapy extremely complex. Consequently, the authors have developed a decision analysis system that simultaneously confronts diseases, urodynamic manifestations, risks for the patient, and the main therapeutic approaches available. In 1985, they increased the number of stages in their continence-micturition model from two the four. This four-stage model has provided satisfactory result when used with an abacus for modeling observed biologic phenomena. In addition to offering simulation exercises for teaching purposes, this abacus provides the means for studying the instantaneous urodynamic situation (correspondences between cycle time points, symptoms, and effects of treatments) and determining the effect of various medicosocial events on the course of the bladder and sphincter dysfunction. The authors hope this abacus will be an attractive aide to the understanding of the complex function of the distal urinary tract.

  1. [Effects of mesenchymal stem cells on cell cycle and apoptosis of hematopoietic tissue cells in irradiated mice].

    Science.gov (United States)

    Hu, Kai-Xun; Zhao, Shi-Fu; Guo, Mei; Ai, Hui-Sheng

    2007-12-01

    protein in control group were more than that in MSC group. It is concluded that the MSCs accelerate the running of cell cycle in these hematopoietic tissue cells of irradiated mice, reduce the cell apoptosis and promote the recovery from injuries in hematopietic and immunological organs, thus protect the irradiated mice at early stage.

  2. Analysis of the Trypanosoma brucei cell cycle by quantitative DAPI imaging.

    Science.gov (United States)

    Siegel, T Nicolai; Hekstra, Doeke R; Cross, George A M

    2008-08-01

    Trypanosoma brucei has two DNA compartments: the nucleus and the kinetoplast. DNA replication of these two compartments only partially coincides. Woodward and Gull [Woodward R, Gull K. Timing of nuclear and kinetoplast DNA replication and early morphological events in the cell cycle of Trypanosoma brucei. J Cell Sci 1990;95:49-57] comprehensively studied the relative timing of the replication and segregation of nuclear DNA (nDNA) and kinetoplast DNA (kDNA). Others have since assumed the consistency of morphological indicators of cell-cycle stage among strains and conditions. We report the use of quantitative DAPI imaging to determine the cell-cycle stage of individual procyclic cells. Using this approach, we found that kinetoplast elongation occurs mainly during nuclear S phase and not during G2, as previously assumed. We confirmed this finding by sorting cells by DNA content, followed by fluorescence microscopy. In addition, simultaneous quantitative imaging at two wavelengths can be used to determine the abundance of cell-cycle-regulated proteins during the cell cycle. We demonstrate this technique by co-staining for the non-acetylated state of lysine 4 of histone H4 (H4K4), which is enriched during nuclear S phase.

  3. On the link between cell cycle and infection of the Alphaproteobacterium Brucella abortus

    Directory of Open Access Journals (Sweden)

    Michaël Deghelt

    2014-09-01

    Full Text Available Bacteria of the Brucella genus are responsible for brucellosis, a worldwide zoonosis. These bacteria are known to have a peculiar intracellular trafficking, with a first long and non-proliferative endosomal stage and a second proliferation stage, often associated with its localization of the bacteria in the endoplasmic reticulum (ER. However, the status of the bacterial cell cycle during the non-proliferative phase was still unknown. In a recent study [Nat. Communic. 5:4366], we followed the cell cycle of B. abortus in culture and inside the host cells. In culture, B. abortus initiates the replication of its large chromosome before the small chromosome. The origin and terminator regions of these two chromosomes display distinct localization and dynamics within B. abortus. In HeLa cells and RAW264.7 macrophages, the bacteria in G1 (i.e. before the initiation of chromosomes replication are preferentially found during the endosomal stage of the infection. During this period, growth is also arrested. The cell cycle arrest and resume during the B. abortus trafficking in host cell suggest that like the model Alphaproteobacterium Caulobacter crescentus, these bacteria are able to block their cell cycle at the G1 phase when starvation is sensed.

  4. Stages of Childhood Extracranial Germ Cell Tumors

    Science.gov (United States)

    ... tumors include the following: Having certain genetic syndromes : Klinefelter syndrome may increase the risk of germ cell ... and procedures may be used: Physical exam and history : An exam of the body to check general ...

  5. Morphological and molecular studies on life cycle stages of Diphtherostomum brusinae (Digenea: Zoogonidae) from northern Portugal.

    Science.gov (United States)

    Pina, S; Tajdari, J; Russell-Pinto, F; Rodrigues, P

    2009-12-01

    Diphtherostomum brusinae was first recorded by the present study in the north of Portugal. Sporocysts, containing cercariae and encysted metacercariae, were observed in the gonads and digestive gland of the gastropod Nassarius reticulatus. Metacercariae were also found infecting the foot, mantle border and gills of the cockle Cerastoderma edule. The adult form was lodged in the rectum of the definitive host Diplodus sargus. The morphology of the three parasitic stages was studied by light (LM) and scanning electron microscopy (SEM). Despite the close similarity between cercaria and metacercaria, SEM data provided information that allowed their differentiation, namely the presence of a dense crown of microvilli around the oral cavity of the cercariae, which was absent in the metacercariae. In addition, the metacercariae presented a specific pre-acetabular rectangular band with conspicuous triangular spines. The adult showed characteristics of D. brusinae species, in particular the presence of acetabular lips, compact vitellaria and large elliptical eggs. Sequenced ITS1 data clearly demonstrated that the cercariae and metacercarial cysts from N. reticulatus, the cysts from C. edule and the adult isolated from D. sargus were life cycle stages that belonged to the same species, i.e. D. brusinae. Two transmission strategies in the life cycle of this species were observed: (1) cercariae encyst within the sporocysts of N. reticulatus and await ingestion by the definitive host; and (2) N. reticulatus naturally emits cercariae; they encyst in C. edule or the environment and are ingested by the definitive host.

  6. Life cycle and immature stages of the arctiid moth, Phoenicoprocta capistrata.

    Science.gov (United States)

    Rodríguez-Loeches, Laura; Barro, Alejandro

    2008-01-01

    Phoenicoprocta capistrata (Fabricius 1775) (Lepidoptera: Arctiidae) is an arctiid moth reported for the Caribbean and Brazil, whose immature stages and life cycle are unknown. In this study, and for the first time, a host plant is registered and the immature stages and the captivity life cycle are described using a Cuban population. Larvae feed on fowlsfoot, Serjania diversifolia (Jacq.) Radlk (Sapindales: Sapindaceae). One complete cohort was obtained from December of 2004 to February of 2005 and about 57 days lapsed from oviposition to adult emergence. The egg is light green-yellowish and semi-spherical. Most larvae developed through 6 or 7 instars, although there were individuals with 8 instars. The last instar has a cephalic capsule width of 2.04 +/- 0.06 mm (n = 29) irrespective of the number of instars. The cephalic capsule growth curves of the larvae with 6 and 7 instars have different slopes, but both follow a geometric pattern consistent with the Dyar's rule. In each larval molt the setae types and the larvae coloration change. Adult females have two color morphs, one orange-reddish and the other blue. Female descendants of blue and red females differ in the proportion of color morphs, which could indicate the existence of a female-limited polymorphism phenomenon in this species.

  7. First Law Analysis of a Two-stage Ejector-vapor Compression Refrigeration Cycle working with R404A

    OpenAIRE

    Feiza Memet; Daniela-Elena Mitu

    2011-01-01

    The traditional two-stage vapor compression refrigeration cycle might be replaced by a two-stage ejector-vapor compression refrigeration cycle if it is aimed the decrease of irreversibility during expansion. In this respect, the expansion valve is changed with an ejector. The performance improvement is searched in the case of choosing R404A as a refrigerant. Using the ejector as an expansion device ensures a higher value for COP compared to the traditional case. On the basis...

  8. Modelled interglacial carbon cycle dynamics during the Holocene, the Eemian and Marine Isotope Stage (MIS) 11

    Science.gov (United States)

    Kleinen, Thomas; Brovkin, Victor; Munhoven, Guy

    2016-11-01

    Trends in the atmospheric concentration of CO2 during three recent interglacials - the Holocene, the Eemian and Marine Isotope Stage (MIS) 11 - are investigated using an earth system model of intermediate complexity, which we extended with process-based modules to consider two slow carbon cycle processes - peat accumulation and shallow-water CaCO3 sedimentation (coral reef formation). For all three interglacials, model simulations considering peat accumulation and shallow-water CaCO3 sedimentation substantially improve the agreement between model results and ice core CO2 reconstructions in comparison to a carbon cycle set-up neglecting these processes. This enables us to model the trends in atmospheric CO2, with modelled trends similar to the ice core data, forcing the model only with orbital and sea level changes. During the Holocene, anthropogenic CO2 emissions are required to match the observed rise in atmospheric CO2 after 3 ka BP but are not relevant before this time. Our model experiments show a considerable improvement in the modelled CO2 trends by the inclusion of the slow carbon cycle processes, allowing us to explain the CO2 evolution during the Holocene and two recent interglacials consistently using an identical model set-up.

  9. The cell cycle of the planctomycete Gemmata obscuriglobus with respect to cell compartmentalization

    Directory of Open Access Journals (Sweden)

    Fuerst John A

    2009-01-01

    well as DNA confirmed the behaviour of the nucleoid and nucleoid envelope during cell division. Electron microscopy of cryosubstituted cells confirmed deductions from light microscopy concerning nucleoid presence in relation to the stage of budding, and showed that the nucleoid was observed to occur in both mother and bud cells only at later budding stages. It further suggested that nucleoid envelope formed only after the nucleoid was translocated into the bud, since envelopes only appeared in more mature buds, while naked nucleoids occurred in smaller buds. Nucleoid envelope appeared to originate from the intracytoplasmic membranes (ICM of both mother cell and bud. There was always a connecting passage between mother cell and bud during the budding process until separation of the two cells. The division cycle of the nucleated planctomycete G. obscuriglobus appears to be a complex process in which chromosomal DNA is transported to the daughter cell bud after initial formation of the bud, and this can be performed repeatedly by a single mother cell. Conclusion The division cycle of the nucleated planctomycete G. obscuriglobus is a complex process in which chromosomal nucleoid DNA is transported to the daughter cell bud after initial formation of a bud without nucleoid. The new bud nucleoid is initially naked and not surrounded by membrane, but eventually acquires a complete nucleoid envelope consisting of two closely apposed membranes as occurs in the mother cell. The membranes of the new nucleoid envelope surrounding the bud nucleoid are derived from intracytoplasmic membranes of both the mother cell and the bud. The cell division of G. obscuriglobus displays some unique features not known in cells of either prokaryotes or eukaryotes.

  10. Cell cycle controls stress response and longevity in C. elegans

    Science.gov (United States)

    Dottermusch, Matthias; Lakner, Theresa; Peyman, Tobias; Klein, Marinella; Walz, Gerd; Neumann-Haefelin, Elke

    2016-01-01

    Recent studies have revealed a variety of genes and mechanisms that influence the rate of aging progression. In this study, we identified cell cycle factors as potent regulators of health and longevity in C. elegans. Focusing on the cyclin-dependent kinase 2 (cdk-2) and cyclin E (cye-1), we show that inhibition of cell cycle genes leads to tolerance towards environmental stress and longevity. The reproductive system is known as a key regulator of longevity in C. elegans. We uncovered the gonad as the central organ mediating the effects of cell cycle inhibition on lifespan. In particular, the proliferating germ cells were essential for conferring longevity. Steroid hormone signaling and the FOXO transcription factor DAF-16 were required for longevity associated with cell cycle inhibition. Furthermore, we discovered that SKN-1 (ortholog of mammalian Nrf proteins) activates protective gene expression and induces longevity when cell cycle genes are inactivated. We conclude that both, germline absence and inhibition through impairment of cell cycle machinery results in longevity through similar pathways. In addition, our studies suggest further roles of cell cycle genes beyond cell cycle progression and support the recently described connection of SKN-1/Nrf to signals deriving from the germline. PMID:27668945

  11. A cell cycle timer for asymmetric spindle positioning.

    Directory of Open Access Journals (Sweden)

    Erin K McCarthy Campbell

    2009-04-01

    Full Text Available The displacement of the mitotic spindle to one side of a cell is important for many cells to divide unequally. While recent progress has begun to unveil some of the molecular mechanisms of mitotic spindle displacement, far less is known about how spindle displacement is precisely timed. A conserved mitotic progression mechanism is known to time events in dividing cells, although this has never been linked to spindle displacement. This mechanism involves the anaphase-promoting complex (APC, its activator Cdc20/Fizzy, its degradation target cyclin, and cyclin-dependent kinase (CDK. Here we show that these components comprise a previously unrecognized timer for spindle displacement. In the Caenorhabditis elegans zygote, mitotic spindle displacement begins at a precise time, soon after chromosomes congress to the metaphase plate. We found that reducing the function of the proteasome, the APC, or Cdc20/Fizzy delayed spindle displacement. Conversely, inactivating CDK in prometaphase caused the spindle to displace early. The consequence of experimentally unlinking spindle displacement from this timing mechanism was the premature displacement of incompletely assembled components of the mitotic spindle. We conclude that in this system, asymmetric positioning of the mitotic spindle is normally delayed for a short time until the APC inactivates CDK, and that this delay ensures that the spindle does not begin to move until it is fully assembled. To our knowledge, this is the first demonstration that mitotic progression times spindle displacement in the asymmetric division of an animal cell. We speculate that this link between the cell cycle and asymmetric cell division might be evolutionarily conserved, because the mitotic spindle is displaced at a similar stage of mitosis during asymmetric cell divisions in diverse systems.

  12. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis

    Science.gov (United States)

    Ingber, D. E.; Prusty, D.; Sun, Z.; Betensky, H.; Wang, N.

    1995-01-01

    Capillary endothelial cells can be switched between growth and differentiation by altering cell-extracellular matrix interactions and thereby, modulating cell shape. Studies were carried out to determine when cell shape exerts its growth-regulatory influence during cell cycle progression and to explore the role of cytoskeletal structure and mechanics in this control mechanism. When G0-synchronized cells were cultured in basic fibroblast growth factor (FGF)-containing defined medium on dishes coated with increasing densities of fibronectin or a synthetic integrin ligand (RGD-containing peptide), cell spreading, nuclear extension, and DNA synthesis all increased in parallel. To determine the minimum time cells must be adherent and spread on extracellular matrix (ECM) to gain entry into S phase, cells were removed with trypsin or induced to retract using cytochalasin D at different times after plating. Both approaches revealed that cells must remain extended for approximately 12-15 h and hence, most of G1, in order to enter S phase. After this restriction point was passed, normally 'anchorage-dependent' endothelial cells turned on DNA synthesis even when round and in suspension. The importance of actin-containing microfilaments in shape-dependent growth control was confirmed by culturing cells in the presence of cytochalasin D (25-1000 ng ml-1): dose-dependent inhibition of cell spreading, nuclear extension, and DNA synthesis resulted. In contrast, induction of microtubule disassembly using nocodazole had little effect on cell or nuclear spreading and only partially inhibited DNA synthesis. Interestingly, combination of nocodazole with a suboptimal dose of cytochalasin D (100 ng ml-1) resulted in potent inhibition of both spreading and growth, suggesting that microtubules are redundant structural elements which can provide critical load-bearing functions when microfilaments are partially compromised. Similar synergism between nocodazole and cytochalasin D was observed

  13. Ocean acidification affects redox-balance and ion-homeostasis in the life-cycle stages of Emiliania huxleyi.

    Directory of Open Access Journals (Sweden)

    Sebastian D Rokitta

    Full Text Available Ocean Acidification (OA has been shown to affect photosynthesis and calcification in the coccolithophore Emiliania huxleyi, a cosmopolitan calcifier that significantly contributes to the regulation of the biological carbon pumps. Its non-calcifying, haploid life-cycle stage was found to be relatively unaffected by OA with respect to biomass production. Deeper insights into physiological key processes and their dependence on environmental factors are lacking, but are required to understand and possibly estimate the dynamics of carbon cycling in present and future oceans. Therefore, calcifying diploid and non-calcifying haploid cells were acclimated to present and future CO(2 partial pressures (pCO(2; 38.5 Pa vs. 101.3 Pa CO(2 under low and high light (50 vs. 300 µmol photons m(-2 s(-1. Comparative microarray-based transcriptome profiling was used to screen for the underlying cellular processes and allowed to follow up interpretations derived from physiological data. In the diplont, the observed increases in biomass production under OA are likely caused by stimulated production of glycoconjugates and lipids. The observed lowered calcification under OA can be attributed to impaired signal-transduction and ion-transport. The haplont utilizes distinct genes and metabolic pathways, reflecting the stage-specific usage of certain portions of the genome. With respect to functionality and energy-dependence, however, the transcriptomic OA-responses resemble those of the diplont. In both life-cycle stages, OA affects the cellular redox-state as a master regulator and thereby causes a metabolic shift from oxidative towards reductive pathways, which involves a reconstellation of carbon flux networks within and across compartments. Whereas signal transduction and ion-homeostasis appear equally OA-sensitive under both light intensities, the effects on carbon metabolism and light physiology are clearly modulated by light availability. These interactive effects

  14. Circulating Tumor DNA in Predicting Outcomes in Patients With Stage IV Head and Neck Cancer or Stage III-IV Non-small Cell Lung Cancer

    Science.gov (United States)

    2016-10-19

    Metastatic Squamous Neck Cancer With Occult Primary Squamous Cell Carcinoma; Salivary Gland Squamous Cell Carcinoma; Stage IIIA Non-small Cell Lung Cancer; Stage IIIB Non-small Cell Lung Cancer; Stage IV Non-small Cell Lung Cancer; Stage IV Squamous Cell Carcinoma of the Hypopharynx; Stage IV Squamous Cell Carcinoma of the Nasopharynx; Stage IVA Salivary Gland Cancer; Stage IVA Squamous Cell Carcinoma of the Larynx; Stage IVA Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage IVA Squamous Cell Carcinoma of the Oropharynx; Stage IVA Squamous Cell Carcinoma of the Paranasal Sinus and Nasal Cavity; Stage IVA Verrucous Carcinoma of the Larynx; Stage IVA Verrucous Carcinoma of the Oral Cavity; Stage IVB Salivary Gland Cancer; Stage IVB Squamous Cell Carcinoma of the Larynx; Stage IVB Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage IVB Squamous Cell Carcinoma of the Oropharynx; Stage IVB Squamous Cell Carcinoma of the Paranasal Sinus and Nasal Cavity; Stage IVB Verrucous Carcinoma of the Larynx; Stage IVB Verrucous Carcinoma of the Oral Cavity; Stage IVC Salivary Gland Cancer; Stage IVC Squamous Cell Carcinoma of the Larynx; Stage IVC Squamous Cell Carcinoma of the Lip and Oral Cavity; Stage IVC Squamous Cell Carcinoma of the Oropharynx; Stage IVC Squamous Cell Carcinoma of the Paranasal Sinus and Nasal Cavity; Stage IVC Verrucous Carcinoma of the Larynx; Stage IVC Verrucous Carcinoma of the Oral Cavity; Tongue Cancer; Untreated Metastatic Squamous Neck Cancer With Occult Primary

  15. Characteristics and Behavior of Cycled Aged Lithium Ion Cells

    Science.gov (United States)

    2010-01-01

    service cycle and provide the cornerstone for safety analysis. 18650 Cells with representative chemistry of cells contained in current Army procured...their relevance to this effort warrants inclusion. 1-3 EXPERIMENTAL Representative 18650 cells were cycled at different rates and environmental...conditions. The 18650 chemistry used in this effort is a LiCoO2 lithium ion electrochemical cell. The bulk of this effort was conducted with 1.5 Amp-hr

  16. Cell cycle-dependent gene networks relevant to cancer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The analysis of sophisticated interplays between cell cycle-dependent genes in a disease condition is one of the largely unexplored areas in modern tumor biology research. Many cell cycle-dependent genes are either oncogenes or suppressor genes, or are closely asso- ciated with the transition of a cell cycle. However, it is unclear how the complicated relationships between these cell cycle-dependent genes are, especially in cancers. Here, we sought to identify significant expression relationships between cell cycle-dependent genes by analyzing a HeLa microarray dataset using a local alignment algorithm and constructed a gene transcriptional network specific to the cancer by assembling these newly identified gene-gene relationships. We further characterized this global network by partitioning the whole network into several cell cycle phase-specific sub-networks. All generated networks exhibited the power-law node-degree dis- tribution, and the average clustering coefficients of these networks were remarkably higher than those of pure scale-free networks, indi- cating a property of hierarchical modularity. Based on the known protein-protein interactions and Gene Ontology annotation data, the proteins encoded by cell cycle-dependent interacting genes tended to share the same biological functions or to be involved in the same biological processes, rather than interacting by physical means. Finally, we identified the hub genes related to cancer based on the topo- logical importance that maintain the basic structure of cell cycle-dependent gene networks.

  17. A Method to Design Synthetic Cell-Cycle Networks

    Institute of Scientific and Technical Information of China (English)

    MIAO Ke-Ke

    2009-01-01

    The interactions among proteins, DNA and RNA in an organism form elaborate cell-cycle networks which govern cell growth and proliferation. Understanding the common structure of ce11-cycle networks will be of great benefit to science research. Here, inspired by the importance of the cell-cycle regulatory network of yeast which has been studied intensively, we focus on small networks with 11 nodes, equivalent to that of the cell-cycle regulatory network used by Li et al. [Proc. Natl. Acad. Sci. USA 101(2004)4781] Using a Boolean model, we study the correlation between structure and function, and a possible common structure. It is found that cascade-like networks with a great number of interactions between nodes are stable. Based on these findings, we are able to construct synthetic networks that have the same functions as the cell-cycle regulatory network.

  18. The vicious cycle of apoptotic beta-cell death in type 1 diabetes.

    Science.gov (United States)

    Kaminitz, Ayelet; Stein, Jerry; Yaniv, Isaac; Askenasy, Nadir

    2007-01-01

    Autoimmune insulitis, the cause of type 1 diabetes, evolves through several discrete stages that culminate in beta-cell death. In the first stage, antigenic epitopes of B-cell-specific peptides are processed by antigen presenting cells in local lymph nodes, and auto-reactive lymphocyte clones are propagated. Subsequently, cell-mediated and direct cytokine-mediated reactions are generated against the beta-cells, and the beta-cells are sensitized to apoptosis. Ironically, the beta-cells themselves contribute some of the cytokines and chemokines that provoke the immune reaction within the islets. Once this vicious cycle of autoimmunity is fully developed, the fate of the beta-cells in the islets is sealed, and clinical diabetes inevitably ensues. Differences in various aspects of these concurrent events appear to underlie the significant discrepancies in experimental data observed in experimental models that simulate autoimmune insulitis.

  19. Parametric theoretical study of a two-stage solar organic Rankine cycle for RO desalination

    Energy Technology Data Exchange (ETDEWEB)

    Kosmadakis, G.; Manolakos, D.; Papadakis, G. [Department of Natural Resources and Agricultural Engineering, Agricultural University of Athens, 75 Iera Odos Street, 11855 Athens (Greece)

    2010-05-15

    The present work concerns the parametric study of an autonomous, two-stage solar organic Rankine cycle for RO desalination. The main goal of the current simulation is to estimate the efficiency, as well as to calculate the annual mechanical energy available for desalination in the considered cases, in order to evaluate the influence of various parameters on the performance of the system. The parametric study concerns the variation of different parameters, without changing actually the baseline case. The effect of the collectors' slope and the total number of evacuated tube collectors used, have been extensively examined. The total cost is also taken into consideration and is calculated for the different cases examined, along with the specific fresh water cost (EUR/m{sup 3}). (author)

  20. Magnetocaloric cycle with six stages: Possible application of graphene at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Reis, M. S., E-mail: marior@if.uff.br [Instituto de Física, Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza s/n, 24210-346 Niterói, RJ (Brazil)

    2015-09-07

    The present work proposes a thermodynamic hexacycle based on the magnetocaloric oscillations of graphene, which has either a positive or negative adiabatic temperature change depending on the final value of the magnetic field change. For instance, for graphenes at 25 K, an applied field of 2.06 T/1.87 T promotes a temperature change of ca. −25 K/+3 K. The hexacycle is based on the Brayton cycle and instead of the usual four steps, it has six stages, taking advantage of the extra cooling provided by the inverse adiabatic temperature change. This proposal opens doors for magnetic cooling applications at low temperatures.

  1. Stage-specific requirement for cyclin D1 in glial progenitor cells of the cerebral cortex.

    Science.gov (United States)

    Nobs, Lionel; Baranek, Constanze; Nestel, Sigrun; Kulik, Akos; Kapfhammer, Josef; Nitsch, Cordula; Atanasoski, Suzana

    2014-05-01

    Despite the vast abundance of glial progenitor cells in the mouse brain parenchyma, little is known about the molecular mechanisms driving their proliferation in the adult. Here we unravel a critical role of the G1 cell cycle regulator cyclin D1 in controlling cell division of glial cells in the cortical grey matter. We detect cyclin D1 expression in Olig2-immunopositive (Olig2+) oligodendrocyte progenitor cells, as well as in Iba1+ microglia and S100β+ astrocytes in cortices of 3-month-old mice. Analysis of cyclin D1-deficient mice reveals a cell and stage-specific molecular control of cell cycle progression in the various glial lineages. While proliferation of fast dividing Olig2+ cells at early postnatal stages becomes gradually dependent on cyclin D1, this particular G1 regulator is strictly required for the slow divisions of Olig2+/NG2+ oligodendrocyte progenitors in the adult cerebral cortex. Further, we find that the population of mature oligodendrocytes is markedly reduced in the absence of cyclin D1, leading to a significant decrease in the number of myelinated axons in both the prefrontal cortex and the corpus callosum of 8-month-old mutant mice. In contrast, the pool of Iba1+ cells is diminished already at postnatal day 3 in the absence of cyclin D1, while the number of S100β+ astrocytes remains unchanged in the mutant.

  2. 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.

  3. The Cell Cycle: An Activity Using Paper Plates to Represent Time Spent in Phases of the Cell Cycle

    Science.gov (United States)

    Scherer, Yvette D.

    2014-01-01

    In this activity, students are given the opportunity to combine skills in math and geometry for a biology lesson in the cell cycle. Students utilize the data they collect and analyze from an online onion-root-tip activity to create a paper-plate time clock representing a 24-hour cell cycle. By dividing the paper plate into appropriate phases of…

  4. The cell cycle regulated transcriptome of Trypanosoma brucei.

    Directory of Open Access Journals (Sweden)

    Stuart K Archer

    Full Text Available Progression of the eukaryotic cell cycle requires the regulation of hundreds of genes to ensure that they are expressed at the required times. Integral to cell cycle progression in yeast and animal cells are temporally controlled, progressive waves of transcription mediated by cell cycle-regulated transcription factors. However, in the kinetoplastids, a group of early-branching eukaryotes including many important pathogens, transcriptional regulation is almost completely absent, raising questions about the extent of cell-cycle regulation in these organisms and the mechanisms whereby regulation is achieved. Here, we analyse gene expression over the Trypanosoma brucei cell cycle, measuring changes in mRNA abundance on a transcriptome-wide scale. We developed a "double-cut" elutriation procedure to select unperturbed, highly synchronous cell populations from log-phase cultures, and compared this to synchronization by starvation. Transcriptome profiling over the cell cycle revealed the regulation of at least 430 genes. While only a minority were homologous to known cell cycle regulated transcripts in yeast or human, their functions correlated with the cellular processes occurring at the time of peak expression. We searched for potential target sites of RNA-binding proteins in these transcripts, which might earmark them for selective degradation or stabilization. Over-represented sequence motifs were found in several co-regulated transcript groups and were conserved in other kinetoplastids. Furthermore, we found evidence for cell-cycle regulation of a flagellar protein regulon with a highly conserved sequence motif, bearing similarity to consensus PUF-protein binding motifs. RNA sequence motifs that are functional in cell-cycle regulation were more widespread than previously expected and conserved within kinetoplastids. These findings highlight the central importance of post-transcriptional regulation in the proliferation of parasitic kinetoplastids.

  5. Cell cycle regulation by glucosamine in human pulmonary epithelial cells.

    Science.gov (United States)

    Chuang, Kun-Han; Lu, Chih-Shen; Kou, Yu Ru; Wu, Yuh-Lin

    2013-04-01

    Airway epithelial cells play an important role against intruding pathogens. Glucosamine, a commonly used supplemental compound, has recently begun to be regarded as a potential anti-inflammatory molecule. This study aimed to uncover how glucosamine impacts on cellular proliferation in human alveolar epithelial cells (A549) and bronchial epithelial cells (HBECs). With trypan blue-exclusion assay, we observed that glucosamine (10, 20, 50 mM) caused a decrease in cell number at 24 and 48 h; with a flow cytometric analysis, we also noted an enhanced cell accumulation within the G(0)/G(1) phase at 24 h and induction of late apoptosis at 24 and 48 h by glucosamine (10, 20, 50 mM) in A549 cells and HBECs. Examination of phosphorylation in retinoblastoma (Rb) protein, we found an inhibitory effect by glucosamine at 20 and 50 mM. Glucosamine at 50 mM was demonstrated to elevate both the mRNA and protein expression of p53 and heme oxygenase-1 (HO-1), but also caused a reduction in p21 protein expression. In addition, glucosamine attenuated p21 protein stability via the proteasomal proteolytic pathway, as well as inducing p21 nuclear accumulation. Altogether, our results suggest that a high dose of glucosamine may inhibit cell proliferation through apoptosis and disturb cell cycle progression with a halt at G(0)/G(1) phase, and that this occurs, at least in part, by a reduction in Rb phosphorylation together with modulation of p21, p53 and HO-1 expression, and nuclear p21 accumulation.

  6. Cholesterol biosynthesis and homeostasis in regulation of the cell cycle.

    Directory of Open Access Journals (Sweden)

    Pushpendra Singh

    Full Text Available The cell cycle is a ubiquitous, multi-step process that is essential for growth and proliferation of cells. The role of membrane lipids in cell cycle regulation is not explored well, although a large number of cytoplasmic and nuclear regulators have been identified. We focus in this work on the role of membrane cholesterol in cell cycle regulation. In particular, we have explored the stringency of the requirement of cholesterol in the regulation of cell cycle progression. For this purpose, we utilized distal and proximal inhibitors of cholesterol biosynthesis, and monitored their effect on cell cycle progression. We show that cholesterol content increases in S phase and inhibition of cholesterol biosynthesis results in cell cycle arrest in G1 phase under certain conditions. Interestingly, G1 arrest mediated by cholesterol biosynthesis inhibitors could be reversed upon metabolic replenishment of cholesterol. Importantly, our results show that the requirement of cholesterol for G1 to S transition is absolute, and even immediate biosynthetic precursors of cholesterol, differing with cholesterol merely in a double bond, could not replace cholesterol for reversing the cell cycle arrest. These results are useful in the context of diseases, such as cancer and Alzheimer's disease, that are associated with impaired cholesterol biosynthesis and homeostasis.

  7. Disconnected circadian and cell cycles in a tumor-driven cell line

    OpenAIRE

    Pendergast, Julie S.; Yeom, Mijung; Bryan A. Reyes; Ohmiya, Yoshihiro; Yamazaki, Shin

    2010-01-01

    Cell division occurs at a specific time of day in numerous species, suggesting that the circadian and cell cycles are coupled in vivo. By measuring the cell cycle rhythm in real-time, we recently showed that the circadian and cell cycles are not coupled in immortalized fibroblasts, resulting in a rapid rate of cell division even though the circadian rhythm is normal in these cells. Here we report that tumor-driven Lewis lung carcinoma (LLC) cells have perfectly temperature compensated circadi...

  8. Plasmodium falciparum full life cycle and Plasmodium ovale liver stages in humanized mice

    Science.gov (United States)

    Soulard, Valérie; Bosson-Vanga, Henriette; Lorthiois, Audrey; Roucher, Clémentine; Franetich, Jean- François; Zanghi, Gigliola; Bordessoulles, Mallaury; Tefit, Maurel; Thellier, Marc; Morosan, Serban; Le Naour, Gilles; Capron, Frédérique; Suemizu, Hiroshi; Snounou, Georges; Moreno-Sabater, Alicia; Mazier, Dominique

    2015-01-01

    Experimental studies of Plasmodium parasites that infect humans are restricted by their host specificity. Humanized mice offer a means to overcome this and further provide the opportunity to observe the parasites in vivo. Here we improve on previous protocols to achieve efficient double engraftment of TK-NOG mice by human primary hepatocytes and red blood cells. Thus, we obtain the complete hepatic development of P. falciparum, the transition to the erythrocytic stages, their subsequent multiplication, and the appearance of mature gametocytes over an extended period of observation. Furthermore, using sporozoites derived from two P. ovale-infected patients, we show that human hepatocytes engrafted in TK-NOG mice sustain maturation of the liver stages, and the presence of late-developing schizonts indicate the eventual activation of quiescent parasites. Thus, TK-NOG mice are highly suited for in vivo observations on the Plasmodium species of humans. PMID:26205537

  9. Cell cycle-dependent induction of autophagy, mitophagy and reticulophagy.

    Science.gov (United States)

    Tasdemir, Ezgi; Maiuri, M Chiara; Tajeddine, Nicolas; Vitale, Ilio; Criollo, Alfredo; Vicencio, José Miguel; Hickman, John A; Geneste, Olivier; Kroemer, Guido

    2007-09-15

    When added to cells, a variety of autophagy inducers that operate through distinct mechanisms and target different organelles for autophagic destruction (mitochondria in mitophagy, endoplasmic reticulum in reticulophagy) rarely induce autophagic vacuolization in more than 50% or the cells. Here we show that this heterogeneity may be explained by cell cycle-specific effects. The BH3 mimetic ABT737, lithium, rapamycin, tunicamycin or nutrient depletion stereotypically induce autophagy preferentially in the G(1) and S phases of the cell cycle, as determined by simultaneous monitoring of cell cycle markers and the cytoplasmic aggregation of GFP-LC3 in autophagic vacuoles. These results point to a hitherto neglected crosstalk between autophagic vacuolization and cell cycle regulation.

  10. BENZO[a]PYRENE DIOL EPOXIDE PERTURBATION OF CELL CYCLE KINETICS OF SYNCHRONIZED MOUSE LIVER EPITHELIAL CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Pearlman, A.L.; Navsky, B.N.; Bartholomew, J.C

    1980-07-01

    A cell cycle synchronization system is described for the analysis of the perturbation of cell cycle kinetics and the cycle-phase specificity of chemicals and other agents. We used the system to study the effects of ({+-})r-7, t-8-dihydroxy-t-9, 10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BaP diol epoxide) upon the cell cycle of mouse liver epithelial cells(NMuLi). BaP diol epoxide(0.6 uM) was added to replated cultures of NMuLi cells that had been synchronized in various stages of the cell cycle by centrifugal elutriation. DNA histograms were obtained by flow cytometry as a function of time after replating. The data were analyzed by a computer modeling routine and reduced to a few graphs illustrating the 'net effects' of the BaP diol epoxide relative to controls. BaP diol epoxide slowed S-phase traversal in all samples relative to their respective control. Traversal through G{sub 2}M was also slowed by at least 50%. BaP diol epoxide had no apparent effect upon G{sub 1} traversal by cycling cells, but delayed the recruitment of quiescent G{sub 0} cells by about 2 hrs. The methods described constitute a powerful new approach for probing the cell cycle effects of a wide variety of agents. The present system appears to be extremely sensitive and capable of characterizing the action of agents on each phase of the cell cycle. The methods are automatable and would allow for the assay and possible differential characterization of mutagens and carcinogens.

  11. WNT5A modulates cell cycle progression and contributes to the chemoresistance in pancreatic cancer cells

    Institute of Scientific and Technical Information of China (English)

    Wei Wei; Hui-Hui Sun; Na Li; Hong-Yue Li; Xin Li; Qiang Li; Xiao-Hong Shen

    2014-01-01

    BACKGROUND: Although there are many studies on the mechanism of chemoresistance in cancers, studies on the relations between WNT5A and chemoresistance in pancreatic cancer are rare. The present study was to examine the role of WNT5A in the regulation of cell cycle progression and in chemoresistance in pancreatic cancer tissues and cell lines. METHODS: Fresh pancreatic cancer and paracarcinoma tissues were obtained from 32 patients. The expressions of WNT5A, AKT/p-AKT and Cyclin D1 were detected by immunohistochemistry, and the correlation between WNT5A expression and clinicopathological characteristics was analyzed. The relationship between WNT5A expression and gemcitabine resistance was studied in PANC-1 and MIAPaCa2 cell lines. The effect of WNT5A on the regulation of cell cycle and gemcitabine cytotoxicity were investigated. The associations among the expressions of p-AKT, Cyclin D1 and WNT5A were also analyzed in cell lines and the effect of WNT5A on restriction-point (R-point) progression was evaluated. RESULTS: WNT5A, p-AKT and Cyclin D1 were highly expressed in pancreatic cancer tissues, and the WNT5A expression was correlated with the TNM stages. In vitro, WNT5A expression was associated with gemcitabine chemoresistance. The percentage of cells was increased in G0/G1 phase and decreased in S phase after knockdown of WNT5A in PANC-1. WNT5A promoted Cyclin D1 expression through phosphorylation of AKT which consequently enhanced G1-S transition and gemcitabine resistance. Furthermore, WNT5A enhanced the cell cycle progression toward R-point through regulation of retinoblastoma protein (pRb) and pRb-E2F complex formation. CONCLUSIONS: WNT5A induced chemoresistance by regulation of G1-S transition in pancreatic cancer cells. WNT5A might serve as a predictor of gemcitabine response and as a potential target for tumor chemotherapy.

  12. Centrosome detection in sea urchin eggs with a monoclonal antibody against Drosophila intermediate filament proteins: characterization of stages of the division cycle of centrosomes.

    Science.gov (United States)

    Schatten, H; Walter, M; Mazia, D; Biessmann, H; Paweletz, N; Coffe, G; Schatten, G

    1987-12-01

    A mouse monoclonal antibody generated against Drosophila intermediate filament proteins (designated Ah6/5/9 and referred to herein as Ah6) is found to cross-react specifically with centrosomes in sea urchin eggs and with a 68-kDa antigen in eggs and isolated mitotic apparatus. When preparations stained with Ah6 are counterstained with a human autoimmune serum whose anti-centrosome activity has been established, the immunofluorescence images superimpose exactly. A more severe test of the specificity of the antibody demands that it display all of the stages of the centrosome cycle in the cell cycle: the flattening and spreading of the compact centrosomes followed by their division and the establishment of two compact poles. The test was made by an experimental design that uses a period of exposure of the eggs to 2-mercaptoethanol. This treatment allows observation of the stages of the centrosome cycle--separation, division, and bipolarization--while the chromosomes are arrested in metaphase. Mitosis is arrested in the presence of 0.1 M 2-mercaptoethanol. Chromosomes remain in a metaphase configuration while the centrosomes divide, producing four poles perpendicular to the original spindle axis. Microtubules are still present in the mitotic apparatus, as indicated by immunofluorescence and transmission electron microscopy. When 2-mercaptoethanol is removed, the chromosomes reorient to the poles of a tetrapolar (sometimes tripolar) mitotic apparatus. During the following cycle, the blastomeres form a monopolar mitotic apparatus. The observations of the centrosome cycle with the Ah6 antibody display very clearly all the stages that have been seen or deduced from work with other probes. The 68-kDa antigen that reacts with the Ah6 monoclonal antibody to Drosophila intermediate filament proteins must be a constant component of sea urchin centrosomes because it is present at all stages of the centrosome cycle.

  13. Disconnected circadian and cell cycles in a tumor-driven cell line.

    Science.gov (United States)

    Pendergast, Julie S; Yeom, Mijung; Reyes, Bryan A; Ohmiya, Yoshihiro; Yamazaki, Shin

    2010-11-01

    Cell division occurs at a specific time of day in numerous species, suggesting that the circadian and cell cycles are coupled in vivo. By measuring the cell cycle rhythm in real-time, we recently showed that the circadian and cell cycles are not coupled in immortalized fibroblasts, resulting in a rapid rate of cell division even though the circadian rhythm is normal in these cells. Here we report that tumor-driven Lewis lung carcinoma (LLC) cells have perfectly temperature compensated circadian clocks, but the periods of their cell cycle gene expression rhythms are temperature-dependent, suggesting that their circadian and cell cycles are not connected. These data support our hypothesis that decoupling of the circadian and cell cycles may underlie aberrant cell division in tumor cells.

  14. Cell Cycle Related Differentiation of Bone Marrow Cells into Lung Cells

    Energy Technology Data Exchange (ETDEWEB)

    Dooner, Mark; Aliotta, Jason M.; Pimental, Jeffrey; Dooner, Gerri J.; Abedi, Mehrdad; Colvin, Gerald; Liu, Qin; Weier, Heinz-Ulli; Dooner, Mark S.; Quesenberry, Peter J.

    2007-12-31

    Green-fluorescent protein (GFP) labeled marrow cells transplanted into lethally irradiated mice can be detected in the lungs of transplanted mice and have been shown to express lung specific proteins while lacking the expression of hematopoietic markers. We have studied marrow cells induced to transit cell cycle by exposure to IL-3, IL-6, IL-11 and steel factor at different times of culture corresponding to different phases of cell cycle. We have found that marrow cells at the G1/S interface have a 3-fold increase in cells which assume a lung phenotype and that this increase is no longer seen in late S/G2. These cells have been characterized as GFP{sup +} CD45{sup -} and GFP{sup +} cytokeratin{sup +}. Thus marrow cells with the capacity to convert into cells with a lung phenotype after transplantation show a reversible increase with cytokine induced cell cycle transit. Previous studies have shown the phenotype of bone marrow stem cells fluctuates reversibly as these cells traverse cell cycle, leading to a continuum model of stem cell regulation. The present studies indicate that marrow stem cell production of nonhematopoietic cells also fluctuates on a continuum.

  15. Side population sorting separates subfractions of cycling and non-cycling intestinal stem cells

    Directory of Open Access Journals (Sweden)

    Richard J. von Furstenberg

    2014-03-01

    Full Text Available We report here that side population (SP sorting allows for the simultaneous isolation of two intestinal stem cell (ISC subsets from wild-type (WT mice which are phenotypically different and represent cycling and non-cycling pools of cells. Following 5-ethynyl-2′-deoxyuridine (EdU injection, in the upper side population (USP the percentage of EdU+ was 36% showing this fraction to be highly proliferative. In the lower side population (LSP, only 0.4% of cells were EdU+, indicating this fraction to be predominantly non-cycling. Using Lgr5-EGFP mice, we show that Lgr5-EGFPhi cells, representing actively cycling ISCs, are essentially exclusive to the USP. In contrast, using histone 2B-YFP mice, SP analysis revealed YFP label retaining cells (LRCs in both the USP and the LSP. Correspondingly, evaluation of the SP fractions for mRNA markers by qRT-PCR showed that the USP was enriched in transcripts associated with both quiescent and active ISCs. In contrast, the LSP expressed mRNA markers of quiescent ISCs while being de-enriched for those of the active ISC. Both the USP and LSP are capable of generating enteroids in culture which include the four intestinal lineages. We conclude that sorting of USP and LSP fractions represents a novel isolation of cycling and non-cycling ISCs from WT mice.

  16. Estrogen receptor alpha is cell cycle-regulated and regulates the cell cycle in a ligand-dependent fashion.

    Science.gov (United States)

    JavanMoghadam, Sonia; Weihua, Zhang; Hunt, Kelly K; Keyomarsi, Khandan

    2016-06-17

    Estrogen receptor alpha (ERα) has been implicated in several cell cycle regulatory events and is an important predictive marker of disease outcome in breast cancer patients. Here, we aimed to elucidate the mechanism through which ERα influences proliferation in breast cancer cells. Our results show that ERα protein is cell cycle-regulated in human breast cancer cells and that the presence of 17-β-estradiol (E2) in the culture medium shortened the cell cycle significantly (by 4.5 hours, P fashion. These results provide the rationale for an effective treatment strategy that includes a cell cycle inhibitor in combination with a drug that lowers estrogen levels, such as an aromatase inhibitor, and an antiestrogen that does not result in the degradation of ERα, such as tamoxifen.

  17. Generation of high-producing cell lines by overexpression of cell division cycle 25 homolog A in Chinese hamster ovary cells.

    Science.gov (United States)

    Lee, Kyoung Ho; Tsutsui, Tomomi; Honda, Kohsuke; Asano, Ryutaro; Kumagai, Izumi; Ohtake, Hisao; Omasa, Takeshi

    2013-12-01

    To improve the efficiency of conventional gene amplification systems, the effect of cell cycle modification during the gene amplification process on IgG production was investigated in Chinese hamster ovary (CHO) cells. The full-length cDNA of CHO cell division cycle 25 homolog A (Cdc25A) was introduced into CHO DG44 cells and the effects of CDC25A overexpression on the cell cycle, transgene copy number and IgG productivity were examined. Both wild-type and mutated CDC25A-overexpressing CHO cells showed a rapid increase in transgene copy number compared with mock cells during the gene amplification process, in both cell pools and individual clones. High-producing clones were obtained with high frequency in CDC25A-overexpressing cell pools. The specific production rate of the isolated clone CHO SD-S23 was up to 2.9-fold higher than that of mock cells in the presence of 250 nM methotrexate (MTX). Cell cycle analysis revealed that the G2 to M phase transition rate was increased ∼1.5-fold in CDC25A-overexpressing CHO cells under MTX treatment. Our results show the improvement of conventional gene amplification systems via cell cycle engineering at an early stage of cell line development.

  18. Thermodynamic Analysis of Double-Stage Compression Transcritical CO2 Refrigeration Cycles with an Expander

    Directory of Open Access Journals (Sweden)

    Zhenying Zhang

    2015-04-01

    Full Text Available Four different double-compression CO2 transcritical refrigeration cycles are studied: double-compression external intercooler cycle (DCEI, double-compression external intercooler cycle with an expander (DCEIE, double-compression flash intercooler cycle (DCFI, double-compression flash intercooler cycle with an expander (DCFIE. The results showed that the optimum gas cooler pressure and optimum intermediate pressure of the flash intercooler cycles are lower than that of the external intercooler cycle. The use of an expander in the DCEI cycle leads to a decrease of the optimum gas cooler pressure and little variation of the optimum intermediate pressure. However, the replacement of the throttle valve with an expander in the DCFI cycle results in little variation of the optimal gas cooler pressure and an increase of the optimum intermediate pressure. The DCFI cycle outperforms the DCEI cycle under all the chosen operating conditions. The DCEIE cycle outperforms the DCFIE cycle when the evaporating temperature exceeds 0 °C or the gas cooler outlet temperature surpasses 35 °C. When the gas cooler exit temperature varies from 32 °C to 48 °C, the DCEI cycle, DCEIE cycle, DCFI cycle and DCFIE cycle yield averaged 4.6%, 29.2%, 12.9% and 22.3% COP improvement, respectively, over the basic cycle.

  19. The Syrian Golden Hamster Estrous Cycle: Unique Characteristics, Visual Guide to Staging, and Comparison with the Rat.

    Science.gov (United States)

    Chanut, Franck J A; Williams, Ann M

    2016-01-01

    The Syrian hamster, Mesocricetus auratus, is a suitable rodent species for standard regulatory toxicity studies. However, little is published about the female Syrian hamster reproductive system. It has unique anatomic features that differ from the other rodent species. In the hamster, the upper cervix is composed of 2 canals and the vagina shows 2 lateral pouches where keratin debris accumulates. These pouches must be distinguished from the vagina in order to stage the estrous cycle properly. The microscopic changes occurring during all the estrous cycle stages show some differences with the other rodents, the lower cervix and upper vagina presenting the more dramatic changes. The aim of this work was to produce a practical guide to staging the cycle and to highlight some of the differences between the rat and hamster reproductive system.

  20. Cell-Cycle Inhibition by Helicobacter pylori L-Asparaginase

    Science.gov (United States)

    Scotti, Claudia; Sommi, Patrizia; Pasquetto, Maria Valentina; Cappelletti, Donata; Stivala, Simona; Mignosi, Paola; Savio, Monica; Chiarelli, Laurent Roberto; Valentini, Giovanna; Bolanos-Garcia, Victor M.; Merrell, Douglas Scott; Franchini, Silvia; Verona, Maria Luisa; Bolis, Cristina; Solcia, Enrico; Manca, Rachele; Franciotta, Diego; Casasco, Andrea; Filipazzi, Paola; Zardini, Elisabetta; Vannini, Vanio

    2010-01-01

    Helicobacter pylori (H. pylori) is a major human pathogen causing chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. One of the mechanisms whereby it induces damage depends on its interference with proliferation of host tissues. We here describe the discovery of a novel bacterial factor able to inhibit the cell-cycle of exposed cells, both of gastric and non-gastric origin. An integrated approach was adopted to isolate and characterise the molecule from the bacterial culture filtrate produced in a protein-free medium: size-exclusion chromatography, non-reducing gel electrophoresis, mass spectrometry, mutant analysis, recombinant protein expression and enzymatic assays. L-asparaginase was identified as the factor responsible for cell-cycle inhibition of fibroblasts and gastric cell lines. Its effect on cell-cycle was confirmed by inhibitors, a knockout strain and the action of recombinant L-asparaginase on cell lines. Interference with cell-cycle in vitro depended on cell genotype and was related to the expression levels of the concurrent enzyme asparagine synthetase. Bacterial subcellular distribution of L-asparaginase was also analysed along with its immunogenicity. H. pylori L-asparaginase is a novel antigen that functions as a cell-cycle inhibitor of fibroblasts and gastric cell lines. We give evidence supporting a role in the pathogenesis of H. pylori-related diseases and discuss its potential diagnostic application. PMID:21085483

  1. Studies on regulation of the cell cycle in fission yeast.

    Directory of Open Access Journals (Sweden)

    Miroslava Požgajová

    2015-05-01

    Full Text Available All living organisms including plants and animals are composed of millions of cells. These cells perform different functions for the organism although they possess the same chromosomes and carry the same genetic information. Thus, to be able to understand multicellular organism we need to understand the life cycle of individual cells from which the organism comprises. The cell cycle is the life cycle of a single cell in the plant or animal body. It involves series of events in which components of the cell doubles and afterwards equally segregate into daughter cells. Such process ensures growth of the organism, and specialized reductional cell division which leads to production of gamets, assures sexual reproduction. Cell cycle is divided in the G1, S, G2 and M phase. Two gap-phases (G1 and G2 separate S phase (or synthesis and M phase which stays either for mitosis or meiosis. Essential for normal life progression and reproduction is correct chromosome segregation during mitosis and meiosis. Defects in the division program lead to aneuploidy, which in turn leads to birth defects, miscarriages or cancer. Even thou, researchers invented much about the regulation of the cell cycle, there is still long way to understand the complexity of the regulatory machineries that ensure proper segregation of chromosomes. In this paper we would like to describe techniques and materials we use for our studies on chromosome segregation in the model organism Schizosaccharomyces pombe.

  2. Cell-cycle inhibition by Helicobacter pylori L-asparaginase.

    Directory of Open Access Journals (Sweden)

    Claudia Scotti

    Full Text Available Helicobacter pylori (H. pylori is a major human pathogen causing chronic gastritis, peptic ulcer, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. One of the mechanisms whereby it induces damage depends on its interference with proliferation of host tissues. We here describe the discovery of a novel bacterial factor able to inhibit the cell-cycle of exposed cells, both of gastric and non-gastric origin. An integrated approach was adopted to isolate and characterise the molecule from the bacterial culture filtrate produced in a protein-free medium: size-exclusion chromatography, non-reducing gel electrophoresis, mass spectrometry, mutant analysis, recombinant protein expression and enzymatic assays. L-asparaginase was identified as the factor responsible for cell-cycle inhibition of fibroblasts and gastric cell lines. Its effect on cell-cycle was confirmed by inhibitors, a knockout strain and the action of recombinant L-asparaginase on cell lines. Interference with cell-cycle in vitro depended on cell genotype and was related to the expression levels of the concurrent enzyme asparagine synthetase. Bacterial subcellular distribution of L-asparaginase was also analysed along with its immunogenicity. H. pylori L-asparaginase is a novel antigen that functions as a cell-cycle inhibitor of fibroblasts and gastric cell lines. We give evidence supporting a role in the pathogenesis of H. pylori-related diseases and discuss its potential diagnostic application.

  3. Intercellular Coupling of the Cell Cycle and Circadian Clock in Adult Stem Cell Culture.

    Science.gov (United States)

    Matsu-Ura, Toru; Dovzhenok, Andrey; Aihara, Eitaro; Rood, Jill; Le, Hung; Ren, Yan; Rosselot, Andrew E; Zhang, Tongli; Lee, Choogon; Obrietan, Karl; Montrose, Marshall H; Lim, Sookkyung; Moore, Sean R; Hong, Christian I

    2016-12-01

    Circadian clock-gated cell division cycles are observed from cyanobacteria to mammals via intracellular molecular connections between these two oscillators. Here we demonstrate WNT-mediated intercellular coupling between the cell cycle and circadian clock in 3D murine intestinal organoids (enteroids). The circadian clock gates a population of cells with heterogeneous cell-cycle times that emerge as 12-hr synchronized cell division cycles. Remarkably, we observe reduced-amplitude oscillations of circadian rhythms in intestinal stem cells and progenitor cells, indicating an intercellular signal arising from differentiated cells governing circadian clock-dependent synchronized cell division cycles. Stochastic simulations and experimental validations reveal Paneth cell-secreted WNT as the key intercellular coupling component linking the circadian clock and cell cycle in enteroids.

  4. [Changes in the monoamine content in different parts of hypothalamus depending on the stages of the estrous cycle].

    Science.gov (United States)

    Babichev, V N; Adamskaia, E I

    1976-01-01

    Fluorimetric determination of monoamines in various regions of the hypothalamus and at different stages of the estral cycle in rats showed that the serotonin, noradrenaline, and particularly dophamine content changed both in the course of the cycle and at different time (10, 15 and 18 hours) of the same stage of the cycle. Dophamine concentration in the arcuate area--the centre of the tonic activity--reached its maximum at 18 hours of the diestrus-2 (D2) and fell to the minimum at 10 hours of the proestrus (P). Noradrenaline level in the preoptic area increased at 18 hours of the D2 and fell at 10 hours of the P. It is supposed that in the hypothalamic regulation of the estral cycle at least two monoamines (dopamine and noradrenaline) took part; the trigger role belongs to noradrenaline of the preoptic area (the cyclic centre).

  5. Regulation of cell cycle by the anaphase spindle midzone

    Directory of Open Access Journals (Sweden)

    Sluder Greenfield

    2004-12-01

    Full Text Available Abstract Background A number of proteins accumulate in the spindle midzone and midbody of dividing animal cells. Besides proteins essential for cytokinesis, there are also components essential for interphase functions, suggesting that the spindle midzone and/or midbody may play a role in regulating the following cell cycle. Results We microsurgically severed NRK epithelial cells during anaphase or telophase, such that the spindle midzone/midbody was associated with only one of the daughter cells. Time-lapse recording of cells severed during early anaphase indicated that the cell with midzone underwent cytokinesis-like cortical contractions and progressed normally through the interphase, whereas the cell without midzone showed no cortical contraction and an arrest or substantial delay in the progression of interphase. Similar microsurgery during telophase showed a normal progression of interphase for both daughter cells with or without the midbody. Microsurgery of anaphase cells treated with cytochalasin D or nocodazole indicated that interphase progression was independent of cortical ingression but dependent on microtubules. Conclusions We conclude that the mitotic spindle is involved in not only the separation of chromosomes but also the regulation of cell cycle. The process may involve activation of components in the spindle midzone that are required for the cell cycle, and/or degradation of components that are required for cytokinesis but may interfere with the cell cycle.

  6. First Law Analysis of a Two-stage Ejector-vapor Compression Refrigeration Cycle working with R404A

    Directory of Open Access Journals (Sweden)

    Feiza Memet

    2011-10-01

    Full Text Available The traditional two-stage vapor compression refrigeration cycle might be replaced by a two-stage ejector-vapor compression refrigeration cycle if it is aimed the decrease of irreversibility during expansion. In this respect, the expansion valve is changed with an ejector. The performance improvement is searched in the case of choosing R404A as a refrigerant. Using the ejector as an expansion device ensures a higher value for COP compared to the traditional case. On the basis of the ejector approach it possible to identify the highest COP value for a given condensation temperature, when the evaporation temperature varies.

  7. Two cell cycle blocks caused by iron chelation of neuroblastoma cells: separating cell cycle events associated with each block.

    Science.gov (United States)

    Siriwardana, Gamini; Seligman, Paul A

    2013-12-01

    Studies have presented evidence that besides the well described S phase block, treatment of cancer cell lines with the iron chelator deferrioxamine (DFO) also results in an earlier block in G1 phase. In this article, measurements of cell cycle regulatory proteins define this block at a very specific point in G1. DFO treatment results in markedly decreased cyclin A protein levels. Cyclin E levels that accumulate in early to mid-G1 are increased in cells treated with DFO as compared to the resting cells. The DFO S phase block is shown after cells are arrested at G1/S by (aphidicolin) then released into DFO. The same S phase block occurs with DFO treatment of a neuroblastoma cell line relatively resistant to the G1 DFO block. These experiments clearly differentiate the S phase DFO block from the earlier block pinpointed to a point in mid-G1, before G1/S when cyclin E protein increases but before increased cyclin A synthesis. Apoptosis was observed in cells inhibited by DFO at both cell cycle arrest points.

  8. The circadian clock and cell cycle: interconnected biological circuits.

    Science.gov (United States)

    Masri, Selma; Cervantes, Marlene; Sassone-Corsi, Paolo

    2013-12-01

    The circadian clock governs biological timekeeping on a systemic level, helping to regulate and maintain physiological processes, including endocrine and metabolic pathways with a periodicity of 24-hours. Disruption within the circadian clock machinery has been linked to numerous pathological conditions, including cancer, suggesting that clock-dependent regulation of the cell cycle is an essential control mechanism. This review will highlight recent advances on the 'gating' controls of the circadian clock at various checkpoints of the cell cycle and also how the cell cycle can influence biological rhythms. The reciprocal influence that the circadian clock and cell cycle exert on each other suggests that these intertwined biological circuits are essential and multiple regulatory/control steps have been instated to ensure proper timekeeping.

  9. Technoeconomy of different solid oxide fuel cell based hybrid cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    Gas turbine, steam turbine and heat engine (Stirling engine) is used as bottoming cycle for a solid oxide fuel cell plant to compare different plants efficiencies, CO2 emissionsand plants cost in terms of $/kW. Each plant is then integrated with biomass gasification and finally six plants...... configurations are compared with each other. Technoeconomy is used when calculating the cost if the plants. It is found that when a solid oxide fuel cell plant is combined with a gas turbine cycle then the plant efficiency will be the highest one while if a biomass gasification plant is integrated...... with these hybrid cycles then integrated biomass gasification with solid oxide fuel cell and steam cycle will have the highest plant efficiency. The cost of solid oxide fuel cell with steam plant is found to be the lowest one with a value of about 1030$/kW....

  10. Cellular Clocks : Coupled Circadian Dispatch and Cell Division Cycles

    NARCIS (Netherlands)

    Merrow, Martha; Roenneberg, Till

    2004-01-01

    Gating of cell division by the circadian clock is well known, yet its mechanism is little understood. Genetically tractable model systems have led to new hypotheses and questions concerning the coupling of these two cellular cycles.

  11. Genome-wide examination of myoblast cell cycle withdrawal duringdifferentiation

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Xun; Collier, John Michael; Hlaing, Myint; Zhang, Leanne; Delshad, Elizabeth H.; Bristow, James; Bernstein, Harold S.

    2002-12-02

    Skeletal and cardiac myocytes cease division within weeks of birth. Although skeletal muscle retains limited capacity for regeneration through recruitment of satellite cells, resident populations of adult myocardial stem cells have not been identified. Because cell cycle withdrawal accompanies myocyte differentiation, we hypothesized that C2C12 cells, a mouse myoblast cell line previously used to characterize myocyte differentiation, also would provide a model for studying cell cycle withdrawal during differentiation. C2C12 cells were differentiated in culture medium containing horse serum and harvested at various time points to characterize the expression profiles of known cell cycle and myogenic regulatory factors by immunoblot analysis. BrdU incorporation decreased dramatically in confluent cultures 48 hr after addition of horse serum, as cells started to form myotubes. This finding was preceded by up-regulation of MyoD, followed by myogenin, and activation of Bcl-2. Cyclin D1 was expressed in proliferating cultures and became undetectable in cultures containing 40 percent fused myotubes, as levels of p21(WAF1/Cip1) increased and alpha-actin became detectable. Because C2C12 myoblasts withdraw from the cell cycle during myocyte differentiation following a course that recapitulates this process in vivo, we performed a genome-wide screen to identify other gene products involved in this process. Using microarrays containing approximately 10,000 minimally redundant mouse sequences that map to the UniGene database of the National Center for Biotechnology Information, we compared gene expression profiles between proliferating, differentiating, and differentiated C2C12 cells and verified candidate genes demonstrating differential expression by RT-PCR. Cluster analysis of differentially expressed genes revealed groups of gene products involved in cell cycle withdrawal, muscle differentiation, and apoptosis. In addition, we identified several genes, including DDAH2 and Ly

  12. The C. elegans hox gene lin-39 controls cell cycle progression during vulval development.

    Science.gov (United States)

    Roiz, Daniel; Escobar-Restrepo, Juan Miguel; Leu, Philipp; Hajnal, Alex

    2016-10-01

    Cell fate specification during organogenesis is usually followed by a phase of cell proliferation to produce the required number of differentiated cells. The Caenorhabditis elegans vulva is an excellent model to study how cell fate specification and cell proliferation are coordinated. The six vulval precursor cells (VPCs) are born at the first larval stage, but they arrest in the G1 phase of the cell cycle until the beginning of the third larval stage, when their fates are specified and the three proximal VPCs proliferate to generate 22 vulval cells. An epidermal growth factor (EGF) signal from the gonadal anchor cell combined with lateral DELTA/NOTCH signaling between the VPCs determine the primary (1°) and secondary (2°) fates, respectively. The hox gene lin-39 plays a key role in integrating these spatial patterning signals and in maintaining the VPCs as polarized epithelial cells. Using a fusion-defective eff-1(lf) mutation to keep the VPCs polarized, we find that VPCs lacking lin-39 can neither activate lateral NOTCH signaling nor proliferate. LIN-39 promotes cell cycle progression through two distinct mechanisms. First, LIN-39 maintains the VPCs competent to proliferate by inducing cdk-4 cdk and cye-1 cyclinE expression via a non-canonical HOX binding motif. Second, LIN-39 activates in the adjacent VPCs the NOTCH signaling pathway, which promotes VPC proliferation independently of LIN-39. The hox gene lin-39 is therefore a central node in a regulatory network coordinating VPC differentiation and proliferation.

  13. [Small cell prostatic carcinoma detected at the stage of metastases].

    Science.gov (United States)

    Rabii, Redouane; Meziane, Anas; Taha, Abdelatif; Joual, Abdenabi; El Mrini, Mohamed

    2004-09-01

    Small cell prostatic carcinoma is rare, with a poor prognosis. The authors report a case of small cell prostatic carcinoma in a 30-year-old patient diagnosed at the stage of metastases. Immunohistochemistry showed positive anti-neuron-specific enolase (NSE.) and anti-synaptophysin antibodies, while serum PSA was normal (1.2 ng/ml). The patient was treated by cisplatin-etoposide combination chemotherapy, but died 20 days after the first course.

  14. Surgery in limited stage small cell lung cancer

    DEFF Research Database (Denmark)

    Lassen, U; Hansen, H H

    1999-01-01

    The role of surgery in small cell lung cancer (SCLC) is controversial. Surgery has several potential advantages because it may reduce the frequency of local relapses, it does not impede the intensity of chemotherapy, it does not affect the bone marrow, and surgical staging may be of prognostic...

  15. Development of a Two-Stage Microalgae Dewatering Process – A Life Cycle Assessment Approach

    Science.gov (United States)

    Soomro, Rizwan R.; Zeng, Xianhai; Lu, Yinghua; Lin, Lu; Danquah, Michael K.

    2016-01-01

    Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission, and process cost, is presented. PMID:26904075

  16. The timing of T cell priming and cycling

    Directory of Open Access Journals (Sweden)

    Reinhard eObst

    2015-11-01

    Full Text Available The proliferation of specific lymphocytes is the central tenet of the clonal selection paradigm. Antigen recognition by T cells triggers a series of events that produces expanded clones of differentiated effector cells. TCR signaling events are detectable within seconds and minutes and are likely to continue for hours and days in vivo. Here, I review the work done on the importance of TCR signals in the later part of the expansion phase of the primary T cell response, primarily regarding the regulation of the cell cycle in CD4+ and CD8+ cells. The results suggest a degree of programming by early signals for effector differentiation, particularly in the CD8+ T cell compartment, with optimal expansion supported by persistent antigen presentation later on. Differences to CD4+ T cell expansion and new avenues towards a molecular understanding of cell cycle regulation in lymphocytes are discussed.

  17. Sea urchin akt activity is Runx-dependent and required for post-cleavage stage cell division

    KAUST Repository

    Robertson, Anthony J.

    2013-03-25

    In animal development following the initial cleavage stage of embryogenesis, the cell cycle becomes dependent on intercellular signaling and controlled by the genomically encoded ontogenetic program. Runx transcription factors are critical regulators of metazoan developmental signaling, and we have shown that the sea urchin Runx gene runt-1, which is globally expressed during early embryogenesis, functions in support of blastula stage cell proliferation and expression of the mitogenic genes pkc1, cyclinD, and several wnts. To obtain a more comprehensive list of early runt-1 regulatory targets, we screened a Strongylocentrotus purpuratus microarray to identify genes mis-expressed in mid-blastula stage runt-1 morphants. This analysis showed that loss of Runx function perturbs the expression of multiple genes involved in cell division, including the pro-growth and survival kinase Akt (PKB), which is significantly underexpressed in runt-1 morphants. Further genomic analysis revealed that Akt is encoded by two genes in the S. purpuratus genome, akt-1 and akt-2, both of which contain numerous canonical Runx target sequences. The transcripts of both genes accumulate several fold during blastula stage, contingent on runt-1 expression. Inhibiting Akt expression or activity causes blastula stage cell cycle arrest, whereas overexpression of akt-1 mRNA rescues cell proliferation in runt-1 morphants. These results indicate that post-cleavage stage cell division requires Runx-dependent expression of akt.

  18. Sea urchin akt activity is Runx-dependent and required for post-cleavage stage cell division

    Directory of Open Access Journals (Sweden)

    Anthony J. Robertson

    2013-03-01

    In animal development following the initial cleavage stage of embryogenesis, the cell cycle becomes dependent on intercellular signaling and controlled by the genomically encoded ontogenetic program. Runx transcription factors are critical regulators of metazoan developmental signaling, and we have shown that the sea urchin Runx gene runt-1, which is globally expressed during early embryogenesis, functions in support of blastula stage cell proliferation and expression of the mitogenic genes pkc1, cyclinD, and several wnts. To obtain a more comprehensive list of early runt-1 regulatory targets, we screened a Strongylocentrotus purpuratus microarray to identify genes mis-expressed in mid-blastula stage runt-1 morphants. This analysis showed that loss of Runx function perturbs the expression of multiple genes involved in cell division, including the pro-growth and survival kinase Akt (PKB, which is significantly underexpressed in runt-1 morphants. Further genomic analysis revealed that Akt is encoded by two genes in the S. purpuratus genome, akt-1 and akt-2, both of which contain numerous canonical Runx target sequences. The transcripts of both genes accumulate several fold during blastula stage, contingent on runt-1 expression. Inhibiting Akt expression or activity causes blastula stage cell cycle arrest, whereas overexpression of akt-1 mRNA rescues cell proliferation in runt-1 morphants. These results indicate that post-cleavage stage cell division requires Runx-dependent expression of akt.

  19. NONO couples the circadian clock to the cell cycle.

    Science.gov (United States)

    Kowalska, Elzbieta; Ripperger, Juergen A; Hoegger, Dominik C; Bruegger, Pascal; Buch, Thorsten; Birchler, Thomas; Mueller, Anke; Albrecht, Urs; Contaldo, Claudio; Brown, Steven A

    2013-01-29

    Mammalian circadian clocks restrict cell proliferation to defined time windows, but the mechanism and consequences of this interrelationship are not fully understood. Previously we identified the multifunctional nuclear protein NONO as a partner of circadian PERIOD (PER) proteins. Here we show that it also conveys circadian gating to the cell cycle, a connection surprisingly important for wound healing in mice. Specifically, although fibroblasts from NONO-deficient mice showed approximately normal circadian cycles, they displayed elevated cell doubling and lower cellular senescence. At a molecular level, NONO bound to the p16-Ink4A cell cycle checkpoint gene and potentiated its circadian activation in a PER protein-dependent fashion. Loss of either NONO or PER abolished this activation and circadian expression of p16-Ink4A and eliminated circadian cell cycle gating. In vivo, lack of NONO resulted in defective wound repair. Because wound healing defects were also seen in multiple circadian clock-deficient mouse lines, our results therefore suggest that coupling of the cell cycle to the circadian clock via NONO may be useful to segregate in temporal fashion cell proliferation from tissue organization.

  20. Immature Stages and Life Cycle of the Wasp Moth, Cosmosoma auge (Lepidoptera: Erebidae: Arctiinae under Laboratory Conditions

    Directory of Open Access Journals (Sweden)

    Gunnary León-Finalé

    2014-01-01

    Full Text Available Cosmosoma auge (Linnaeus 1767 (Lepidoptera: Erebidae is a Neotropical arctiid moth common in Cuban mountainous areas; however, its life cycle remains unknown. In this work, C. auge life cycle is described for the first time; also, immature stages are described using a Cuban population. Larvae were obtained from gravid wild females caught in Viñales National Park and were fed with fresh leaves of its host plant, the climbing hempweed Mikania micrantha Kunth (Asterales: Asteraceae, which is a new host plant record. Eggs are hemispherical and hatching occurred five days after laying. Larval period had six instars and lasted between 20 and 22 days. First and last larval stages are easily distinguishable from others. First stage has body covered by chalazae and last stage has body covered by verrucae as other stages but has a tuft on each side of A1 and A7. Eggs and larvae features agree with Arctiinae pattern. Pupal stage lasted eight days, and, in general, females emerge before males as a result of pupal stage duration differences between sexes.

  1. Energy Efficiency as a Factor of Engineering Product Competitiveness and its Formation on Product Economic Life Cycle Stages

    Directory of Open Access Journals (Sweden)

    Ivan V. Evstratov

    2011-11-01

    Full Text Available This article discusses the concept of energy efficiency of enterprises and engineering products. The author research how energy efficiency effect on engineering product competitiveness and how rate of enterprise and engineering product formation on stages of the economic product life cycle.

  2. The Late Stage of T Cell Development within Mouse Thymus

    Institute of Scientific and Technical Information of China (English)

    Weifeng Chen

    2004-01-01

    After positive selection and lineage commitment, the TCRαβ+CD4/CD8 SP medullary thymocytes migrate into and reside in thymic medulla, where they undergo an ordered program of late stage of T cell functional maturation and negative selection to delete self-reactive clones by apoptosis. Accomplishment of this final differentiation pathway, a physiological T cell repertoire is formed : T cells acquire immunocompetence to respond to foreign antigens and tolerance to self-antigens, ready for the emigration to homing to the T cell regions of peripheral lymphoid organs and tissues. In this review, emphases are put on introducing the approaches applied in this area and our own observations. Basically, we have analyzed the late stage of medullary thymocyte phenotypic differentiation pathways of both CD4 SP and CD8 SP medullary thymocytes and the concomitant functional maturation pathway, in particular, of CD4 SP thymocytes. It is to provide a standard to compare the functional capacity of the cells at the developmental stages induced by different conditions. The cellular and molecular basis of this differentiation process has been partially described. Cellular & Molecular Immunology. 2004;1(1):3-11.

  3. The Late Stage of T Cell Development within Mouse Thymus

    Institute of Scientific and Technical Information of China (English)

    WeifengChen

    2004-01-01

    After positive selection and lineage commitment, the TCRαβ+CD4/CD8 SP medullary thymocytes migrate into and reside in thymic medulla, where they undergo an ordered program of late stage of T cell functional maturation and negative selection to delete self-reactive clones by apoptosis. Accomplishment of this final differentiation pathway, a physiological T cell repertoire is formed: T cells acquire immunocompetence to respond to foreign antigens and tolerance to self-antigens, ready for the emigration to homing to the T cell regions of peripheral lymphoid organs and tissues. In this review, emphases are put on introducing the approaches applied in this area and our own observations. Basically, we have analyzed the late stage of medullary thymocyte phenotypic differentiation pathways of both CD4 SP and CD8 SP medullary thymocytes and the concomitant functional maturation pathway, in particular, of CD4 SP thymocytes. It is to provide a standard to compare the functional capacity of the cells at the developmental stages induced by different conditions. The cellular and molecular basis of this differentiation process has been partially described. Cellular & Molecular Immunology. 2004;1(1):3-11.

  4. Circadian gating of the cell cycle revealed in single cyanobacterial cells.

    Science.gov (United States)

    Yang, Qiong; Pando, Bernardo F; Dong, Guogang; Golden, Susan S; van Oudenaarden, Alexander

    2010-03-19

    Although major progress has been made in uncovering the machinery that underlies individual biological clocks, much less is known about how multiple clocks coordinate their oscillations. We simultaneously tracked cell division events and circadian phases of individual cells of the cyanobacterium Synechococcus elongatus and fit the data to a model to determine when cell cycle progression slows as a function of circadian and cell cycle phases. We infer that cell cycle progression in cyanobacteria slows during a specific circadian interval but is uniform across cell cycle phases. Our model is applicable to the quantification of the coupling between biological oscillators in other organisms.

  5. Focus on Merkel cell carcinoma: diagnosis and staging

    Energy Technology Data Exchange (ETDEWEB)

    Grandhaye, Marion; Teixeira, Pedro Gondim; Blum, Alain [Imagerie Guilloz CHU de Nancy Hopital Central, Nancy (France); Henrot, Philippe [Service de Radiologie Institut de Cancerologie de Lorraine, Vandoeuvre les Nancy (France); Morel, Olivier [Medecine Nucleaire CHU Nancy Hopital Brabois, Vancoeuvre les Nancy (France); Sirveaux, Francois [Service de Chirurgie Centre chirurgical Emile Galle, Nancy (France); Verhaeghe, Jean-Luc [Service de Chirurgie Institut de Cancerologie de Lorraine, Vandoeuvre les Nancy (France)

    2015-06-01

    Merkel cell carcinoma is a rare lymphophilic skin tumor of neuroendocrine origin with the potential for rapid progression. Small, localized lesions are diagnosed and treated clinically, but advanced tumors often undergo imaging evaluation. Due to its rarity, radiologists are unaware of evocative imaging features and usually do not consider Merkel cell carcinoma in the differential diagnosis of soft tissue tumors. Appropriate staging is important to determine appropriate treatment and has an impact on patient prognosis. Multimodality imaging is usually needed, and there is no consensus on the optimal imaging strategy. The purpose of this article is to review various aspects of Merkel cell carcinoma imaging and look in detail at how optimal multimodality staging should be carried out. (orig.)

  6. Involvement of insulin in early development of mouse one-cell stage embryos

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Recent studies have suggested that growth factors and hormones play important roles in cell prolif-eration and differentiation during early embryonic development. In the present study, we examined the expression and localization of insulin in the mouse oocytes and one-cell stage embryos by quantitative ELISA, RT-PCR, Western blot and immunofluorescence. In the mouse oocytes and one-cell stage em-bryos, expression of insulin was uniformly distributed in the cytoplasm. We also examined the expres-sion, activity and localization of mTOR (mammalian target of rapamycin) and p70S6K. The expression of mTOR and p70S6K was not significantly different at the cell cycle of mouse one-cell stage embryos. mTOR and S6K were distributed evenly in the cytoplasm at G1, G2 and M phase phase, but at S phase, the distribution of mTOR and S6K was around the pronucleus. At different phases, the activity of mTOR fluctuated. We also used the PI3K specific inhibitor-Wortmannin to investigate the cleavage rate of eggs. The result showed that the rate obviously decreased. When the mTOR specific inhibitor Rapa-mycin was used, the first mitotic division of the mouse one-cell stage embryo was delayed. These re-sults suggested that insulin was expressed both in mouse oocytes and one-cell stage embryos, and may play functional roles in regulation of mouse early embryogenesis by activating the signal pathway of PI3K/PKB/mTOR/S6K.

  7. Nanosecond pulsed electric fields and the cell cycle

    Science.gov (United States)

    Mahlke, Megan A.

    Exposure to nanosecond pulsed electrical fields (nsPEFs) can cause poration of external and internal cell membranes, DNA damage, and disassociation of cytoskeletal components, all of which are capable of disrupting a cell's ability to replicate. The phase of the cell cycle at the time of exposure is linked to differential sensitivities to nsPEFs across cell lines, as DNA structure, membrane elasticity, and cytoskeletal structure change dramatically during the cell cycle. Additionally, nsPEFs are capable of activating cell cycle checkpoints, which could lead to apoptosis or slow population growth. NsPEFs are emerging as a method for treating tumors via apoptotic induction; therefore, investigating the relevance of nsPEFs and the cell cycle could translate into improved efficacy in tumor treatment. Populations of Jurkat and Chinese Hamster Ovary (CHO) cells were examined post-exposure (10 ns pulse trains at 150kV/cm) by analysis of DNA content via propidium iodide staining and flow cytometric analysis at various time points (1, 6, and 12h post-exposure) to determine population distribution in cell cycle phases. Additionally, CHO and Jurkat cells were synchronized in G1/S and G2/M phases, pulsed, and analyzed to evaluate the role of cell cycle phase in survival of nsPEFs. CHO populations appeared similar to sham populations post-nsPEFs but exhibited arrest in the G1 phase at 6h after exposure. Jurkat cells exhibited increased cell death after nsPEFs compared to CHO cells but did not exhibit checkpoint arrest at any observed time point. The G1/S phase checkpoint is partially controlled by the action of p53; the lack of an active p53 response in Jurkat cells could contribute to their ability to pass this checkpoint and resist cell cycle arrest. Both cell lines exhibited increased sensitivity to nsPEFs in G2/M phase. Live imaging of CHO cells after nsPEF exposure supports the theory of G1/S phase arrest, as a reduced number of cells undergo mitosis within 24 h when

  8. How the cell cycle impacts chromatin architecture and influences cell fate

    Directory of Open Access Journals (Sweden)

    Yiqin eMa

    2015-02-01

    Full Text Available Since the earliest observations of cells undergoing mitosis, it has been clear that there is an intimate relationship between the cell cycle and nuclear chromatin architecture. The nuclear envelope and chromatin undergo robust assembly and disassembly during the cell cycle, and transcriptional and post-transcriptional regulation of histone biogenesis and chromatin modification is controlled in a cell cycle-dependent manner. Chromatin binding proteins and chromatin modifications in turn influence the expression of critical cell cycle regulators, the accessibility of origins for DNA replication, DNA repair, and cell fate. In this review we aim to provide an integrated discussion of how the cell cycle machinery impacts nuclear architecture and vice-versa. We highlight recent advances in understanding cell cycle-dependent histone biogenesis and histone modification deposition, how cell cycle regulators control histone modifier activities, the contribution of chromatin modifications to origin firing for DNA replication, and newly identified roles for nucleoporins in regulating cell cycle gene expression, gene expression memory and differentiation. We close with a discussion of how cell cycle status may impact chromatin to influence cell fate decisions, under normal contexts of differentiation as well as in instances of cell fate re-programming.

  9. Low-Dose Acetylsalicylic Acid in Treating Patients With Stage I-III Non-Small Cell Lung Cancer

    Science.gov (United States)

    2016-06-28

    Adenocarcinoma of the Lung; Recurrent Non-small Cell Lung Cancer; Stage IA Non-small Cell Lung Cancer; Stage IB Non-small Cell Lung Cancer; Stage IIA Non-small Cell Lung Cancer; Stage IIB Non-small Cell Lung Cancer; Stage IIIA Non-small Cell Lung Cancer; Stage IIIB Non-small Cell Lung Cancer

  10. The cell cycle-regulated genes of Schizosaccharomyces pombe.

    Directory of Open Access Journals (Sweden)

    Anna Oliva

    2005-07-01

    Full Text Available Many genes are regulated as an innate part of the eukaryotic cell cycle, and a complex transcriptional network helps enable the cyclic behavior of dividing cells. This transcriptional network has been studied in Saccharomyces cerevisiae (budding yeast and elsewhere. To provide more perspective on these regulatory mechanisms, we have used microarrays to measure gene expression through the cell cycle of Schizosaccharomyces pombe (fission yeast. The 750 genes with the most significant oscillations were identified and analyzed. There were two broad waves of cell cycle transcription, one in early/mid G2 phase, and the other near the G2/M transition. The early/mid G2 wave included many genes involved in ribosome biogenesis, possibly explaining the cell cycle oscillation in protein synthesis in S. pombe. The G2/M wave included at least three distinctly regulated clusters of genes: one large cluster including mitosis, mitotic exit, and cell separation functions, one small cluster dedicated to DNA replication, and another small cluster dedicated to cytokinesis and division. S. pombe cell cycle genes have relatively long, complex promoters containing groups of multiple DNA sequence motifs, often of two, three, or more different kinds. Many of the genes, transcription factors, and regulatory mechanisms are conserved between S. pombe and S. cerevisiae. Finally, we found preliminary evidence for a nearly genome-wide oscillation in gene expression: 2,000 or more genes undergo slight oscillations in expression as a function of the cell cycle, although whether this is adaptive, or incidental to other events in the cell, such as chromatin condensation, we do not know.

  11. Plant Characteristics of an Integrated Solid Oxide Fuel Cell Cycle and a Steam Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    Plant characteristics of a system containing a solid oxide fuel cell (SOFC) cycle on the top of a Rankine cycle were investigated. Natural gas (NG) was used as the fuel for the plant. A desulfurization reactor removes the sulfur content in the fuel, while a pre-reformer broke down the heavier...... hydrocarbons in an adiabatic steam reformer (ASR). The pre-treated fuel then entered to the anode side of the SOFC. The remaining fuels after the SOFC stacks entered a catalytic burner for further combusting. The burned gases from the burner were then used to produce steam for the Rankine cycle in a heat...... recovery steam generator (HRSG). The remaining energy of the off-gases was recycled back to the topping cycle for further utilization. Several parameter studies were carried out to investigate the sensitivity of the suggested plant. It was shown that the operation temperature of the desulfurization unit...

  12. Cycle life characteristics of Li-TiS2 cells

    Science.gov (United States)

    Deligiannis, Frank; Shen, D.; Huang, C. K.; Surampudi, S.

    1991-01-01

    The development of lithium ambient temperature rechargeable cells is discussed. During the development process, we hope to gain a greater understanding of the materials and the properties of the Li-TiS2 cell and its components. The design will meet the requirements of 100 Wh/Kg and 1000 cycles, at 50 percent depth-of-discharge, by 1995.

  13. Interictal spike frequency varies with ovarian cycle stage in a rat model of epilepsy.

    Science.gov (United States)

    D'Amour, James; Magagna-Poveda, Alejandra; Moretto, Jillian; Friedman, Daniel; LaFrancois, John J; Pearce, Patrice; Fenton, Andre A; MacLusky, Neil J; Scharfman, Helen E

    2015-07-01

    In catamenial epilepsy, seizures exhibit a cyclic pattern that parallels the menstrual cycle. Many studies suggest that catamenial seizures are caused by fluctuations in gonadal hormones during the menstrual cycle, but this has been difficult to study in rodent models of epilepsy because the ovarian cycle in rodents, called the estrous cycle, is disrupted by severe seizures. Thus, when epilepsy is severe, estrous cycles become irregular or stop. Therefore, we modified kainic acid (KA)- and pilocarpine-induced status epilepticus (SE) models of epilepsy so that seizures were rare for the first months after SE, and conducted video-EEG during this time. The results showed that interictal spikes (IIS) occurred intermittently. All rats with regular 4-day estrous cycles had IIS that waxed and waned with the estrous cycle. The association between the estrous cycle and IIS was strong: if the estrous cycles became irregular transiently, IIS frequency also became irregular, and when the estrous cycle resumed its 4-day pattern, IIS frequency did also. Furthermore, when rats were ovariectomized, or males were recorded, IIS frequency did not show a 4-day pattern. Systemic administration of an estrogen receptor antagonist stopped the estrous cycle transiently, accompanied by transient irregularity of the IIS pattern. Eventually all animals developed severe, frequent seizures and at that time both the estrous cycle and the IIS became irregular. We conclude that the estrous cycle entrains IIS in the modified KA and pilocarpine SE models of epilepsy. The data suggest that the ovarian cycle influences more aspects of epilepsy than seizure susceptibility.

  14. Effects of ultraviolet irradiation on the cell cycle.

    Science.gov (United States)

    Bolognia, J L; Sodi, S A; Chakraborty, A K; Fargnoli, M C; Pawelek, J M

    1994-10-01

    Cultured mouse Cloudman melanoma cells, EMT6 breast carcinoma cells, and 3T3 fibroblasts all accumulated in the G2/M phase of the cell cycle when exposed to UVB radiation. The effects of UVB were maximal at 20-30 mJ/cm2 for all three cell lines, and could be observed by flow cytometry as early as 12 hr post irradiation. It has been known since the mid-1970s that MSH receptor binding activity is highest on Cloudman melanoma cells when they are in the G2/M phase of their cycle. Here we show that either UVB irradiation or synchronization of Cloudman cells with colchicine results in a stimulation of MSH binding within 24 hr following treatment, a time when both treatments have resulted in accumulation of cells in the G2/M phase of the cycle. Furthermore, the two treatments performed together on the melanoma cells stimulated MSH receptor activity to the same extent as either treatment performed separately, suggesting that each may be influencing MSH receptor activity solely through a G2/M accumulation of cells. Together, these results raise the possibility that an increase in the number of cells in the G2 phase of the cell cycle is a generalized cellular response to injury, such as UV irradiation. However, in the case of pigment cells this response includes a mechanism for increasing melanin formation, i.e., increased MSH receptor activity. Should this be the case, similar G2/M "injury responses" of other cell types might be expected, consistent with their differentiated phenotypes.

  15. CycleBase.org - a comprehensive multi-organism online database of cell-cycle experiments

    DEFF Research Database (Denmark)

    Gauthier, Nicholas Paul; Larsen, Malene Erup; Wernersson, Rasmus

    2007-01-01

    .org, for viewing and downloading these data. The user interface facilitates searches for genes of interest as well as downloads of genome-wide results. Individual genes are displayed with graphs of expression profiles throughout the cell cycle from all available experiments. These expression profiles...

  16. Differential repair of UV damage in Saccharomyces cerevisiae is cell cycle dependent.

    Science.gov (United States)

    Terleth, C; Waters, R; Brouwer, J; van de Putte, P

    1990-09-01

    In the yeast Saccharomyces cerevisiae the transcriptionally active MAT alpha locus is repaired preferentially to the inactive HML alpha locus after UV irradiation. Here we analysed the repair of both loci after irradiating yeast cells at different stages of the mitotic cell cycle. In all stages repair of the active MAT alpha locus occurs at a rate of 30% removal of dimers per hour after a UV dose of 60 J/m2. The inactive HML alpha is repaired as efficiently as MAT alpha following irradiation in G2 whereas repair of HML alpha is less efficient in the other stages. Thus differential repair is observed in G1 and S but not in G2. Apparently, in G2 a chromatin structure exists in which repair does not discriminate between transcriptionally active and inactive DNA or, alternatively, an additional repair mechanism might exist which is only operational during G2.

  17. Viral infections and cell cycle G2/M regulation

    Institute of Scientific and Technical Information of China (English)

    Richard Y.ZHAO; Robert T.ELDER

    2005-01-01

    Progression of cells from G2 phase of the cell cycle to mitosis is a tightly regulated cellular process that requires activation of the Cdc2 kinase, which determines onset of mitosis in all eukaryotic cells. In both human and fission yeast(Schizosaccharomyces pombe) cells, the activity of Cdc2 is regulated in part by the phosphorylation status of tyrosine 15(Tyr15) on Cdc2, which is phosphorylated by Wee1 kinase during late G2 and is rapidly dephosphorylated by the Cdc25 tyrosine phosphatase to trigger entry into mitosis. These Cdc2 regulators are the downstream targets of two well-characterized G2/M checkpoint pathways which prevent cells from entering mitosis when cellular DNA is damaged or when DNA replication is inhibited. Increasing evidence suggests that Cdc2 is also commonly targeted by viral proteins,which modulate host cell cycle machinery to benefit viral survival or replication. In this review, we describe the effect of viral protein R (Vpr) encoded by human immunodeficiency virus type 1 (HIV-1) on cell cycle G2/M regulation. Based on our current knowledge about this viral effect, we hypothesize that Vpr induces cell cycle G2 arrest through a mechanism that is to some extent different from the classic G2/M checkpoints. One the unique features distinguishing Vpr-induced G2 arrest from the classic checkpoints is the role of phosphatase 2A (PP2A) in Vpr-induced G2 arrest.Interestingly, PP2A is targeted by a number of other viral proteins including SV40 small T antigen, polyomavirus T antigen, HTLV Tax and adenovirus E4orf4. Thus an in-depth understanding of the molecular mechanisms underlying Vpr-induced G2 arrest will provide additional insights into the basic biology of cell cycle G2/M regulation and into the biological significance of this effect during host-pathogen interactions.

  18. A combined gas cooled nuclear reactor and fuel cell cycle

    Science.gov (United States)

    Palmer, David J.

    Rising oil costs, global warming, national security concerns, economic concerns and escalating energy demands are forcing the engineering communities to explore methods to address these concerns. It is the intention of this thesis to offer a proposal for a novel design of a combined cycle, an advanced nuclear helium reactor/solid oxide fuel cell (SOFC) plant that will help to mitigate some of the above concerns. Moreover, the adoption of this proposal may help to reinvigorate the Nuclear Power industry while providing a practical method to foster the development of a hydrogen economy. Specifically, this thesis concentrates on the importance of the U.S. Nuclear Navy adopting this novel design for its nuclear electric vessels of the future with discussion on efficiency and thermodynamic performance characteristics related to the combined cycle. Thus, the goals and objectives are to develop an innovative combined cycle that provides a solution to the stated concerns and show that it provides superior performance. In order to show performance, it is necessary to develop a rigorous thermodynamic model and computer program to analyze the SOFC in relation with the overall cycle. A large increase in efficiency over the conventional pressurized water reactor cycle is realized. Both sides of the cycle achieve higher efficiencies at partial loads which is extremely important as most naval vessels operate at partial loads as well as the fact that traditional gas turbines operating alone have poor performance at reduced speeds. Furthermore, each side of the cycle provides important benefits to the other side. The high temperature exhaust from the overall exothermic reaction of the fuel cell provides heat for the reheater allowing for an overall increase in power on the nuclear side of the cycle. Likewise, the high temperature helium exiting the nuclear reactor provides a controllable method to stabilize the fuel cell at an optimal temperature band even during transients helping

  19. Labeling of lectin receptors during the cell cycle.

    Science.gov (United States)

    Garrido, J

    1976-12-01

    Labeling of lectin receptors during the cell cycle. (Localizabión de receptores para lectinas durante el ciclo celular). Arch. Biol. Med. Exper. 10: 100-104, 1976. The topographic distribution of specific cell surface receptors for concanavalin A and wheat germ agglutinin was studied by ultrastructural labeling in the course of the cell cycle. C12TSV5 cells were synchronized by double thymidine block or mechanical selection (shakeoff). They were labeled by means of lectin-peroxidase techniques while in G1 S, G2 and M phases of the cycle. The results obtained were similar for both lectins employed. Interphase cells (G1 S, G2) present a stlihtly discontinous labeling pattern that is similar to the one observed on unsynchronized cells of the same line. Cells in mitosis, on the contrary, present a highly discontinous distribution of reaction product. This pattern disappears after the cells enters G1 and is not present on mitotic cells fixed in aldehyde prior to labeling.

  20. Computation Molecular Kinetics Model of HZE Induced Cell Cycle Arrest

    Science.gov (United States)

    Cucinotta, Francis A.; Ren, Lei

    2004-01-01

    Cell culture models play an important role in understanding the biological effectiveness of space radiation. High energy and charge (HZE) ions produce prolonged cell cycle arrests at the G1/S and G2/M transition points in the cell cycle. A detailed description of these phenomena is needed to integrate knowledge of the expression of DNA damage in surviving cells, including the determination of relative effectiveness factors between different types of radiation that produce differential types of DNA damage and arrest durations. We have developed a hierarchical kinetics model that tracks the distribution of cells in various cell phase compartments (early G1, late G1, S, G2, and M), however with transition rates that are controlled by rate-limiting steps in the kinetics of cyclin-cdk's interactions with their families of transcription factors and inhibitor molecules. The coupling of damaged DNA molecules to the downstream cyclin-cdk inhibitors is achieved through a description of the DNA-PK and ATM signaling pathways. For HZE irradiations we describe preliminary results, which introduce simulation of the stochastic nature of the number of direct particle traversals per cell in the modulation of cyclin-cdk and cell cycle population kinetics. Comparison of the model to data for fibroblast cells irradiated photons or HZE ions are described.

  1. Cell Division, a new open access online forum for and from the cell cycle community

    Directory of Open Access Journals (Sweden)

    Kaldis Philipp

    2006-04-01

    Full Text Available Abstract Cell Division is a new, open access, peer-reviewed online journal that publishes cutting-edge articles, commentaries and reviews on all exciting aspects of cell cycle control in eukaryotes. A major goal of this new journal is to publish timely and significant studies on the aberrations of the cell cycle network that occur in cancer and other diseases.

  2. Cell "circadian" cycle: new role for mammalian core clock genes.

    Science.gov (United States)

    Borgs, Laurence; Beukelaers, Pierre; Vandenbosch, Renaud; Belachew, Shibeshih; Nguyen, Laurent; Malgrange, Brigitte

    2009-03-15

    In mammals, 24 hours rhythms are organized as a biochemical network of molecular clocks that are operative in all tissues, with the master clock residing in the hypothalamic suprachiasmatic nucleus (SCN). The core pacemakers of these clocks consist of auto-regulatory transcriptional/post-transcriptional feedback loops. Several lines of evidence suggest the existence of a crosstalk between molecules that are responsible for the generation of circadian rhythms and molecules that control the cell cycle progression. In addition, highly specialized cell cycle checkpoints involved in DNA repair after damage seem also, at least in part, mediated by clock proteins. Recent studies have also highlighted a putative connection between clock protein dysfunction and cancer progression. This review discusses the intimate relation that exists between cell cycle progression and components of the circadian machinery.

  3. Using a GFP-gene fusion technique to study the cell cycle-dependent distribution of calmodulin in living cells

    Institute of Scientific and Technical Information of China (English)

    李朝军; 吕品; 张东才

    1999-01-01

    In this study, a green fluorescent protein (GFP)-calmodulin (CaM) fusion gene method was used to examine the distribution of calmodulin during various stages of cell cycle. First, it was found that the distribution of CaM in living cells changes with the cell cycle. CaM was found mainly in the cytoplasm during G1 phase. It began to move into the nucleus when the cell entered S phase. At G2 phase, CaM became more concentrated in the nucleus than in cytoplasm. Second, the accumulation of CaM in the nucleus during G2 phase appeared to be related to the onset of mitosis, since inhibiting the activation of CaM at this stage resulted in blocking the nuclear membrane breakdown and chromatin condensation. Finally, after the cell entered mitosis, a high concentration of CaM was found at the polar regions of the mitotic spindle. At this time, inhibiting the activity of CaM would cause a disruption of the spindle structure. The relationship between the stage-specific distribution of CaM and its function in regulat

  4. Coordinating cell polarity and cell cycle progression: what can we learn from flies and worms?

    Science.gov (United States)

    Noatynska, Anna; Tavernier, Nicolas; Gotta, Monica; Pintard, Lionel

    2013-08-07

    Spatio-temporal coordination of events during cell division is crucial for animal development. In recent years, emerging data have strengthened the notion that tight coupling of cell cycle progression and cell polarity in dividing cells is crucial for asymmetric cell division and ultimately for metazoan development. Although it is acknowledged that such coupling exists, the molecular mechanisms linking the cell cycle and cell polarity machineries are still under investigation. Key cell cycle regulators control cell polarity, and thus influence cell fate determination and/or differentiation, whereas some factors involved in cell polarity regulate cell cycle timing and proliferation potential. The scope of this review is to discuss the data linking cell polarity and cell cycle progression, and the importance of such coupling for asymmetric cell division. Because studies in model organisms such as Caenorhabditis elegans and Drosophila melanogaster have started to reveal the molecular mechanisms of this coordination, we will concentrate on these two systems. We review examples of molecular mechanisms suggesting a coupling between cell polarity and cell cycle progression.

  5. Comparative anatomy and histology of developmental and parasitic stages in the life cycle of the lined sea anemone Edwardsiella lineata.

    Science.gov (United States)

    Reitzel, Adam M; Daly, Marymegan; Sullivan, James C; Finnerty, John R

    2009-02-01

    The evolution of parasitism is often accompanied by profound changes to the developmental program. However, relatively few studies have directly examined the developmental evolution of parasitic species from free-living ancestors. The lined sea anemone Edwardsiella lineata is a relatively recently evolved parasite for which closely related free-living outgroups are known, including the starlet sea anemone Nematostella vectensis. The larva of E. lineata parasitizes the ctenophore Mnemiopsis leidyi, and, once embedded in its host, the anemone assumes a novel vermiform body plan. That we might begin to understand how the developmental program of this species has been transformed during the evolution of parasitism, we characterized the gross anatomy, histology, and cnidom of the parasitic stage, post-parasitic larval stage, and adult stage of the E. lineata life cycle. The distinct parasitic stage of the life cycle differs from the post-parasitic larva with respect to overall shape, external ciliation, cnida frequency, and tissue architecture. The parasitic stage and planula both contain holotrichs, a type of cnida not previously reported in Edwardsiidae. The internal morphology of the post-parasitic planula is extremely similar to the adult morphology, with a complete set of mesenterial tissue and musculature despite this stage having little external differentiation. Finally, we observed 2 previously undocumented aspects of asexual reproduction in E. lineata: (1) the parasitic stage undergoes transverse fission via physal pinching, the first report of asexual reproduction in a pre-adult stage in the Edwardsiidae; and (2) the juvenile polyp undergoes transverse fission via polarity reversal, the first time this form of fission has been reported in E. lineata.

  6. Vertebrate Cell Cycle Modulates Infection by Protozoan Parasites

    Science.gov (United States)

    Dvorak, James A.; Crane, Mark St. J.

    1981-11-01

    Synchronized HeLa cell populations were exposed to Trypanosoma cruzi or Toxoplasma gondii, obligate intracellular protozoan parasites that cause Chagas' disease and toxoplasmosis, respectively, in humans. The ability of the two parasites to infect HeLa cells increased as the HeLa cells proceeded from the G1 phase to the S phase of their growth cycle and decreased as the cells entered G2-M. Characterization of the S-phase cell surface components responsible for this phenomenon could be beneficial in the development of vaccines against these parasitic diseases.

  7. Modelling cell cycle synchronisation in networks of coupled radial glial cells.

    Science.gov (United States)

    Barrack, Duncan S; Thul, Rüdiger; Owen, Markus R

    2015-07-21

    Radial glial cells play a crucial role in the embryonic mammalian brain. Their proliferation is thought to be controlled, in part, by ATP mediated calcium signals. It has been hypothesised that these signals act to locally synchronise cell cycles, so that clusters of cells proliferate together, shedding daughter cells in uniform sheets. In this paper we investigate this cell cycle synchronisation by taking an ordinary differential equation model that couples the dynamics of intracellular calcium and the cell cycle and extend it to populations of cells coupled via extracellular ATP signals. Through bifurcation analysis we show that although ATP mediated calcium release can lead to cell cycle synchronisation, a number of other asynchronous oscillatory solutions including torus solutions dominate the parameter space and cell cycle synchronisation is far from guaranteed. Despite this, numerical results indicate that the transient and not the asymptotic behaviour of the system is important in accounting for cell cycle synchronisation. In particular, quiescent cells can be entrained on to the cell cycle via ATP mediated calcium signals initiated by a driving cell and crucially will cycle in near synchrony with the driving cell for the duration of neurogenesis. This behaviour is highly sensitive to the timing of ATP release, with release at the G1/S phase transition of the cell cycle far more likely to lead to near synchrony than release during mid G1 phase. This result, which suggests that ATP release timing is critical to radial glia cell cycle synchronisation, may help us to understand normal and pathological brain development.

  8. An apoptotic cell cycle mutant in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Villadsen, Ingrid

    1996-01-01

    The simple eukaryote Saccharomyces cerevisiae has proved to be a useful organism for elucidating the mechanisms that govern cell cycle progression in eukaryotic cells. The excellent in vivo system permits a cell cycle study using temperature sensitive mutants. In addition, it is possible to study...... many genes and gene products from higher eukaryotes in Saccharomyces cerevisiae because many genes and biological processes are homologous or similar in lower and in higher eukaryotes. The highly developed methods of genetics and molecular biology greatly facilitates studies of higher eukaryotic...... processes.Programmmed cell death with apoptosis plays a major role in development and homeostatis in most, if not all, animal cells. Apoptosis is a morphologically distinct form of death, that requires the activation of a highly regulated suicide program. Saccharomyces cerevisiae provides a new system...

  9. Cyclin-dependent kinase inhibitor p20 controls circadian cell-cycle timing.

    Science.gov (United States)

    Laranjeiro, Ricardo; Tamai, T Katherine; Peyric, Elodie; Krusche, Peter; Ott, Sascha; Whitmore, David

    2013-04-23

    Specific stages of the cell cycle are often restricted to particular times of day because of regulation by the circadian clock. In zebrafish, both mitosis (M phase) and DNA synthesis (S phase) are clock-controlled in cell lines and during embryo development. Despite the ubiquitousness of this phenomenon, relatively little is known about the underlying mechanism linking the clock to the cell cycle. In this study, we describe an evolutionarily conserved cell-cycle regulator, cyclin-dependent kinase inhibitor 1d (20 kDa protein, p20), which along with p21, is a strongly rhythmic gene and directly clock-controlled. Both p20 and p21 regulate the G1/S transition of the cell cycle. However, their expression patterns differ, with p20 predominant in developing brain and peak expression occurring 6 h earlier than p21. p20 expression is also p53-independent in contrast to p21 regulation. Such differences provide a unique mechanism whereby S phase is set to different times of day in a tissue-specific manner, depending on the balance of these two inhibitors.

  10. Glucocorticoids play a key role in circadian cell cycle rhythms.

    Directory of Open Access Journals (Sweden)

    Thomas Dickmeis

    2007-04-01

    Full Text Available Clock output pathways play a pivotal role by relaying timing information from the circadian clock to a diversity of physiological systems. Both cell-autonomous and systemic mechanisms have been implicated as clock outputs; however, the relative importance and interplay between these mechanisms are poorly understood. The cell cycle represents a highly conserved regulatory target of the circadian timing system. Previously, we have demonstrated that in zebrafish, the circadian clock has the capacity to generate daily rhythms of S phase by a cell-autonomous mechanism in vitro. Here, by studying a panel of zebrafish mutants, we reveal that the pituitary-adrenal axis also plays an essential role in establishing these rhythms in the whole animal. Mutants with a reduction or a complete absence of corticotrope pituitary cells show attenuated cell-proliferation rhythms, whereas expression of circadian clock genes is not affected. We show that the corticotrope deficiency is associated with reduced cortisol levels, implicating glucocorticoids as a component of a systemic signaling pathway required for circadian cell cycle rhythmicity. Strikingly, high-amplitude rhythms can be rescued by exposing mutant larvae to a tonic concentration of a glucocorticoid agonist. Our work suggests that cell-autonomous clock mechanisms are not sufficient to establish circadian cell cycle rhythms at the whole-animal level. Instead, they act in concert with a systemic signaling environment of which glucocorticoids are an essential part.

  11. Implementation of Life Cycle Assessment (LCA) in the early stages of product development

    DEFF Research Database (Denmark)

    Bhander, Gurbakhash Singh; Hauschild, Michael Zwicky; McAloone, Timothy Charles

    2003-01-01

    of freedom and environmental solutions. Life cycle design frameworks and strategies are addressed. The paper collects experiences and ideas around the state-of-the-art in eco-design, from literature and personal experience and further provides eco-design life cycle assessment strategies. The result...

  12. Telomere and telomerase in the initial stage of immortalization of esophageal epithelial cell

    Institute of Scientific and Technical Information of China (English)

    Zhong-Ying Shen; Li-Yan Xu; En-Min Li; Wei-Jia Cai; Min-Hua Chen; Jian Shen; Yi Zeng

    2002-01-01

    AIM: To search for the biomarker of cellular immortalization,the telomere length, telomerase activity and its subunits incultured epithelial cells of human fetal esophagus in theprocess of immortalization.METHODS: The transgenic cell line of human fetalesophageal epithelium (SHEE) was established with E6 E7genes of bt man papillomavirus (HPV) type 18 in ourlaboratory. Morphological phenotype of cultured SHEE cellsfrom the 6th to 30th passages, was examined by phasecontrast microscopy, the telomere length was assayed bySouthern blot method, and the activity of telomerase wasanalyzed by telomeric repeat amplification protocol (TRAP).Expressions of subunits of telomerase, hTR and hTERT,were assessed by RT-PCR. DNA content in cell cycle wasdetected by flow cytometry. The cell apoptosis wasexamined by electron microscopy (EM) and TUNEL label.RESULTS: SHEE cells from the 6 th to 10 th passagesshowed cellular proliferation with a good differentiation.From the 12 th to the 16 th passages, many senescent andapoptotic cells appeared, and the telomere length sharplyshortened from 23 kb to 17 kb without expression of hTERTand telornerase activity. At the 20 th passage, SHEE cellsovercame the senescence and apoptosis and restored theirproliferative activity with expression of telomerase andhTERT at low levels, but the telomere length shortenedcontinuously to the lowest of 3 kb. After the 30 th passagecells proliferation was restored by increment of cells at S andG2M phase in the cell cycle end telomerase activity expressedat high levels and with maintenance of telomere length.CONCLUSION: At the early stage of SHEE cells, telomeresare shortened without expression of telomerase and hTERTcausing cellular senescence and cell death. From the 20 thto the 30 th passages, the activation of telomerase andmaintenance of telomere length show a progressive processfor immortalization of esophageal epithelial cells. Theexpression of telomerase may constitute a biomarker fordetection of

  13. Impact of cell cycle delay on micronucleus frequency in TK6 cells.

    Science.gov (United States)

    Sobol, Zhanna; Spellman, Richard A; Thiffeault, Catherine; Dobo, Krista L; Schuler, Maik

    2014-01-01

    Previous studies with TK6 cells have shown that extending the recovery period after pulse treatment allows for greater micronucleus expression for some compounds. This study explores the role of cell cycle delay in micronucleus expression after pulse treatment with three model genotoxins [mitomycin C, etoposide (ETOP), vinblastine]. Cells were treated for 4 hr and allowed to recover for 36 hr with samples removed at various time points during the recovery period and analyzed for cell cycle distribution, apoptosis and micronucleus frequency. Our results show that mitomycin C causes cell cycle delay for 20 hr after pulse treatment and cell cycle perturbation is no longer evident after 36 hr of recovery. The micronucleus frequency of cells sampled at 36 hr is doubled when compared with cells sampled at 20 hr after mitomycin C removal. When cells were treated with indirect acting genotoxins (ETOP, vinblastine), cell cycle perturbation was not observed at the 20 hr time point. Micronucleus frequency after treatment with either ETOP or vinblastine did not differ between the 20 hr and the 36 hr time point. All three compounds induced similar levels of apoptosis ranging from 4.5 to 5.6% with maximum induction occurring at the 36-hr time point. We conclude that TK6 cells exhibit extended cell cycle arrest after exposure to MMC and can go on to express micronuclei, after overcoming cell cycle arrest.

  14. Visualisation of cell cycle modifications by X-ray irradiation of single HeLa cells using fluorescent ubiquitination-based cell cycle indicators.

    Science.gov (United States)

    Kaminaga, K; Noguchi, M; Narita, A; Sakamoto, Y; Kanari, Y; Yokoya, A

    2015-09-01

    To explore the effects of X-ray irradiation on mammalian cell cycle dynamics, single cells using the fluorescent ubiquitination-based cell cycle indicator (Fucci) technique were tracked. HeLa cells expressing Fucci were used to visualise cell cycle modifications induced by irradiation. After cultured HeLa-Fucci cells were exposed to 5 Gy X-rays, fluorescent cell images were captured every 20 min for 48 h using a fluorescent microscope. Time dependence of the fluorescence intensity of S/G2 cells was analysed to examine the cell cycle dynamics of irradiated and non-irradiated control cells. The results showed that irradiated cells could be divided into two populations: one with similar cell cycle dynamics to that of non-irradiated cells, and another displaying a prolonged G2 phase. Based on these findings, it is proposed in this article that an underlying switch mechanism is involved in cell cycle regulation and the G2/M checkpoint of HeLa cells.

  15. Perceived Risk Influence on the Consumer Attitude to Private Labels in the Product’s Life Cycle Growth Stage

    Directory of Open Access Journals (Sweden)

    Sandra Horvat

    2013-12-01

    Full Text Available The aim of this paper is to explore the relationship between purchasing risk associated with private labels and consumer attitudes towards private labels in different product categories in the growth stage of the product life cycle. The first part of the paper is devoted to a brief literature review of the relevant constructs. The second part describes the research and summarizes its results. Descriptive research was conducted on the Croatian market relating to private labels in three different product categories in the growth stage of the product life cycle: liquid soap, chocolate and facial care products. The results confirm negative correlation between perceived risk and attitudes towards private labels in all analysed categories.

  16. Circadian rhythm variation of the clock genes Per1 and cell cycle related genes in different stages of carcinogenesis of buccal mucosa in animal model%鼠口腔黏膜癌变过程中生物钟基因Per1与细胞周期基因昼夜节律的表达

    Institute of Scientific and Technical Information of China (English)

    谭雪梅; 叶华; 杨凯; 陈丹; 唐洪

    2015-01-01

    Objective To investigate the expression and circadian rhythm variation of biological clock gene Per1 and cell cycle genes p53,CyclinD1,cyclin-dependent kinases (CDK1),CyclinB1 in different stages of carcinogenesis in buccal mucosa and its relationship with the development of buccal mucosa carcinoma.Methods Ninety golden hamsters were housed under 12 hours light-12 hours dark cycles,and the model of buccal squamous cell carcinoma was established by using the dimethylbenzanthracene(DMBA) to smear the golden hamster buccal mucosa.Before the DMBA was used and after DMBA was used 6 weeks and 14 weeks respectively,the golden hamsters were sacrificed at 6 different time points (5 rats per time point) within 24 hour,including 4,8,12,16,20 and 24 hour after lights onset(HALO),and the normal buccal mucosa,precancerous lesions and cancer tissue were obtained,respectively.HE stained sections were prepared to observe the canceration of each tissue.Real time RT-PCR was used to detect the mRNA expression of Per1,p53,CyclinD1,CDK1 and CyclinB1,and a cosine analysis method was applied to determine the circadian rhythm variation of Per1,p53,CyclinD1,CDK1 and CyclinB1 mRNA expression,which were characterized by median,amplitude and acrophase.Results The expression of Per1,p53,CDK1 and CyclinD1 mRNA in 6 different time points within 24 hours in the tissues of three different stages of carcinogenesis had circadian rhythm,respectively.However,the CyclinB 1 mRNA was expressed with circadian rhythm just in normal and cancer tissue (P<0.05),while in precancerous lesions the circadian rhythm was in disorder (P>0.05).As the development of carcinoma,the median of Per 1 and p53 mRNA expression were significantly decreased (P<0.05),yet the median of CDK1,CyclinB1 and CyclinD1 mRNA expression were significantly increased (P<0.05).The amplitude of Per1,p53 and CyclinD1 mRNA expression was significantly decreased as the development of carcinoma (P<0.05),however the amplitude of CDK1 m

  17. Arginine starvation in colorectal carcinoma cells: Sensing, impact on translation control and cell cycle distribution.

    Science.gov (United States)

    Vynnytska-Myronovska, Bozhena O; Kurlishchuk, Yuliya; Chen, Oleh; Bobak, Yaroslav; Dittfeld, Claudia; Hüther, Melanie; Kunz-Schughart, Leoni A; Stasyk, Oleh V

    2016-02-01

    Tumor cells rely on a continued exogenous nutrient supply in order to maintain a high proliferative activity. Although a strong dependence of some tumor types on exogenous arginine sources has been reported, the mechanisms of arginine sensing by tumor cells and the impact of changes in arginine availability on translation and cell cycle regulation are not fully understood. The results presented herein state that human colorectal carcinoma cells rapidly exhaust the internal arginine sources in the absence of exogenous arginine and repress global translation by activation of the GCN2-mediated pathway and inhibition of mTOR signaling. Tumor suppressor protein p53 activation and G1/G0 cell cycle arrest support cell survival upon prolonged arginine starvation. Cells with the mutant or deleted TP53 fail to stop cell cycle progression at defined cell cycle checkpoints which appears to be associated with reduced recovery after durable metabolic stress triggered by arginine withdrawal.

  18. The Effect of Spaceflight on Cartilage Cell Cycle and Differentiation

    Science.gov (United States)

    Doty, Stephen B.; Stiner, Dalina; Telford, William G.

    2000-01-01

    In vivo studies have shown that spaceflight results in loss of bone and muscle. In an effort to understand the mechanisms of these changes, cell cultures of cartilage, bone and muscle have been subjected to spaceflight to study the microgravity effects on differentiated cells. However it now seems possible that the cell differentiation process itself may be the event(s) most affected by spaceflight. For example, osteoblast-like cells have been shown to have reduced cellular activity in microgravity due to an underdifferentiated state (Carmeliet, et al, 1997). And reduced human lymphocyte growth in spaceflight was related to increased apoptosis (Lewis, et al, 1998). Which brings us to the question of whether reduced cellular activity in space is due to an effect on the differentiated cell, an effect on the cell cycle and cell proliferation, or an effect on cell death. This question has not been specifically addressed on previous flights and was the question behind die present study.

  19. Knowledge and communication skills to entrepreneurs in the early stages of the organizational life cycle of Adizes

    OpenAIRE

    Eduardo de Carli; Alexandre Meira de Vasconcelos; Álvaro Guillermo Rojas Lezana

    2014-01-01

    This article identifies the communication skills and knowledge necessary to the entrepreneur during the growth phase of the organizational life cycle of Adizes (2004): Courtship, Infancy, Go-go, Adolescence and Prime. This is a theoretical prescriptive study based on OLC model of Adizes and theoretical and empirical articles on communication and entrepreneurship. It was observed that, at each stage, the entrepreneur must access it and / or develop it for the organization to survive and advanc...

  20. Host cell poly(ADP-ribose glycohydrolase is crucial for Trypanosoma cruzi infection cycle.

    Directory of Open Access Journals (Sweden)

    Salomé C Vilchez Larrea

    Full Text Available Trypanosoma cruzi, etiological agent of Chagas' disease, has a complex life cycle which involves the invasion of mammalian host cells, differentiation and intracellular replication. Here we report the first insights into the biological role of a poly(ADP-ribose glycohydrolase in a trypanosomatid (TcPARG. In silico analysis of the TcPARG gene pointed out the conservation of key residues involved in the catalytic process and, by Western blot, we demonstrated that it is expressed in a life stage-dependant manner. Indirect immunofluorescence assays and electron microscopy using an anti-TcPARG antibody showed that this enzyme is localized in the nucleus independently of the presence of DNA damage or cell cycle stage. The addition of poly(ADP-ribose glycohydrolase inhibitors ADP-HPD (adenosine diphosphate (hydroxymethyl pyrrolidinediol or DEA (6,9-diamino-2-ethoxyacridine lactate monohydrate to the culture media, both at a 1 µM concentration, reduced in vitro epimastigote growth by 35% and 37% respectively, when compared to control cultures. We also showed that ADP-HPD 1 µM can lead to an alteration in the progression of the cell cycle in hydroxyurea synchronized cultures of T. cruzi epimastigotes. Outstandingly, here we demonstrate that the lack of poly(ADP-ribose glycohydrolase activity in Vero and A549 host cells, achieved by chemical inhibition or iRNA, produces the reduction of the percentage of infected cells as well as the number of amastigotes per cell and trypomastigotes released, leading to a nearly complete abrogation of the infection process. We conclude that both, T. cruzi and the host, poly(ADP-ribose glycohydrolase activities are important players in the life cycle of Trypanosoma cruzi, emerging as a promising therapeutic target for the treatment of Chagas' disease.

  1. Plasma Ghrelin Concentrations Were Altered with Oestrous Cycle Stage and Increasing Age in Reproductively Competent Wistar Females

    Science.gov (United States)

    Saffrey, M. Jill; Taylor, Victoria J.

    2016-01-01

    Changes in appetite occur during the ovarian cycle in female mammals. Research on appetite-regulatory gastrointestinal peptides in females is limited, because reproductive changes in steroid hormones present additional experimental factors to control for. This study aimed to explore possible changes in the orexigenic (appetite-stimulating) gastrointestinal peptide hormone ghrelin during the rodent oestrous cycle. Fed and fasted plasma and stomach tissue samples were taken from female Wistar rats (32–44 weeks of age) at each stage of the oestrous cycle for total ghrelin quantification using radioimmunoassay. Sampling occurred during the dark phase when most eating takes place in rats. Statistical analysis was by paired-samples t-test, one-way ANOVA on normally distributed data, with Tukey post-hoc tests, or Kruskal-Wallis if not. GLM univariate analysis was used to assess main effects and interactions in ghrelin concentrations in the fed or fasted state and during different stages of the ovarian cycle, with age as a covariate. No consistent fed to fasted ghrelin increases were measured in matched plasma samples from the same animals, contrary to expectations. Total ghrelin concentrations did not significantly change between cycle stages with ANOVA, in either fed or fasted plasma or in stomach tissue. This was despite significantly decreased fasted stomach contents at oestrus (P = 0.028), suggesting decreased food intake. There was however a significant interaction in ghrelin plasma concentrations between fed and fasted proestrus rats and a direct effect of age with rats over 37 weeks old having lower circulating concentrations of ghrelin in both fed and fasted states. The biological implications of altered ghrelin plasma concentrations from 37 weeks of age are as yet unknown, but warrant further investigation. Exploring peripheral ghrelin regulatory factor changes with increasing age in reproductively competent females may bring to light potential effects on

  2. α-Mangostin Induces Apoptosis and Cell Cycle Arrest in Oral Squamous Cell Carcinoma Cell

    Science.gov (United States)

    Kwak, Hyun-Ho; Park, Bong-Soo

    2016-01-01

    Mangosteen has long been used as a traditional medicine and is known to have antibacterial, antioxidant, and anticancer effects. Although the effects of α-mangostin, a natural compound extracted from the pericarp of mangosteen, have been investigated in many studies, there is limited data on the effects of the compound in human oral squamous cell carcinoma (OSCC). In this study, α-mangostin was assessed as a potential anticancer agent against human OSCC cells. α-Mangostin inhibited cell proliferation and induced cell death in OSCC cells in a dose- and time-dependent manner with little to no effect on normal human PDLF cells. α-Mangostin treatment clearly showed apoptotic evidences such as nuclear fragmentation and accumulation of annexin V and PI-positive cells on OSCC cells. α-Mangostin treatment also caused the collapse of mitochondrial membrane potential and the translocation of cytochrome c from the mitochondria into the cytosol. The expressions of the mitochondria-related proteins were activated by α-mangostin. Treatment with α-mangostin also induced G1 phase arrest and downregulated cell cycle-related proteins (CDK/cyclin). Hence, α-mangostin specifically induces cell death and inhibits proliferation in OSCC cells via the intrinsic apoptosis pathway and cell cycle arrest at the G1 phase, suggesting that α-mangostin may be an effective agent for the treatment of OSCC. PMID:27478478

  3. α-Mangostin Induces Apoptosis and Cell Cycle Arrest in Oral Squamous Cell Carcinoma Cell

    Directory of Open Access Journals (Sweden)

    Hyun-Ho Kwak

    2016-01-01

    Full Text Available Mangosteen has long been used as a traditional medicine and is known to have antibacterial, antioxidant, and anticancer effects. Although the effects of α-mangostin, a natural compound extracted from the pericarp of mangosteen, have been investigated in many studies, there is limited data on the effects of the compound in human oral squamous cell carcinoma (OSCC. In this study, α-mangostin was assessed as a potential anticancer agent against human OSCC cells. α-Mangostin inhibited cell proliferation and induced cell death in OSCC cells in a dose- and time-dependent manner with little to no effect on normal human PDLF cells. α-Mangostin treatment clearly showed apoptotic evidences such as nuclear fragmentation and accumulation of annexin V and PI-positive cells on OSCC cells. α-Mangostin treatment also caused the collapse of mitochondrial membrane potential and the translocation of cytochrome c from the mitochondria into the cytosol. The expressions of the mitochondria-related proteins were activated by α-mangostin. Treatment with α-mangostin also induced G1 phase arrest and downregulated cell cycle-related proteins (CDK/cyclin. Hence, α-mangostin specifically induces cell death and inhibits proliferation in OSCC cells via the intrinsic apoptosis pathway and cell cycle arrest at the G1 phase, suggesting that α-mangostin may be an effective agent for the treatment of OSCC.

  4. Effects of cell cycle noise on excitable gene circuits

    CERN Document Server

    Veliz-Cuba, Alan; Bennett, Matthew R; Josić, Krešimir; Ott, William

    2016-01-01

    We assess the impact of cell cycle noise on gene circuit dynamics. For bistable genetic switches and excitable circuits, we find that transitions between metastable states most likely occur just after cell division and that this concentration effect intensifies in the presence of transcriptional delay. We explain this concentration effect with a 3-states stochastic model. For genetic oscillators, we quantify the temporal correlations between daughter cells induced by cell division. Temporal correlations must be captured properly in order to accurately quantify noise sources within gene networks.

  5. Cell cycle-arrested tumor cells exhibit increased sensitivity towards TRAIL-induced apoptosis

    Science.gov (United States)

    Ehrhardt, H; Wachter, F; Grunert, M; Jeremias, I

    2013-01-01

    Resting tumor cells represent a huge challenge during anticancer therapy due to their increased treatment resistance. TNF-related apoptosis-inducing ligand (TRAIL) is a putative future anticancer drug, currently in phases I and II clinical studies. We recently showed that TRAIL is able to target leukemia stem cell surrogates. Here, we tested the ability of TRAIL to target cell cycle-arrested tumor cells. Cell cycle arrest was induced in tumor cell lines and xenografted tumor cells in G0, G1 or G2 using cytotoxic drugs, phase-specific inhibitors or RNA interference against cyclinB and E. Biochemical or molecular arrest at any point of the cell cycle increased TRAIL-induced apoptosis. Accordingly, when cell cycle arrest was disabled by addition of caffeine, the antitumor activity of TRAIL was reduced. Most important for clinical translation, tumor cells from three children with B precursor or T cell acute lymphoblastic leukemia showed increased TRAIL-induced apoptosis upon knockdown of either cyclinB or cyclinE, arresting the cell cycle in G2 or G1, respectively. Taken together and in contrast to most conventional cytotoxic drugs, TRAIL exerts enhanced antitumor activity against cell cycle-arrested tumor cells. Therefore, TRAIL might represent an interesting drug to treat static-tumor disease, for example, during minimal residual disease. PMID:23744361

  6. NONO couples the circadian clock to the cell cycle

    OpenAIRE

    Kowalska, Elzbieta; Ripperger, Juergen A.; Hoegger, Dominik C.; Bruegger, Pascal; Buch, Thorsten; Birchler, Thomas; Mueller, Anke; Albrecht, Urs; Contaldo, Claudio; Steven A Brown

    2013-01-01

    Mammalian circadian clocks restrict cell proliferation to defined time windows, but the mechanism and consequences of this interrelationship are not fully understood. Previously we identified the multifunctional nuclear protein NONO as a partner of circadian PERIOD (PER) proteins. Here we show that it also conveys circadian gating to the cell cycle, a connection surprisingly important for wound healing in mice. Specifically, although fibroblasts from NONO-deficient mice showed approximately n...

  7. Cell cycle control by a minimal Cdk network.

    Directory of Open Access Journals (Sweden)

    Claude Gérard

    2015-02-01

    Full Text Available In present-day eukaryotes, the cell division cycle is controlled by a complex network of interacting proteins, including members of the cyclin and cyclin-dependent protein kinase (Cdk families, and the Anaphase Promoting Complex (APC. Successful progression through the cell cycle depends on precise, temporally ordered regulation of the functions of these proteins. In light of this complexity, it is surprising that in fission yeast, a minimal Cdk network consisting of a single cyclin-Cdk fusion protein can control DNA synthesis and mitosis in a manner that is indistinguishable from wild type. To improve our understanding of the cell cycle regulatory network, we built and analysed a mathematical model of the molecular interactions controlling the G1/S and G2/M transitions in these minimal cells. The model accounts for all observed properties of yeast strains operating with the fusion protein. Importantly, coupling the model's predictions with experimental analysis of alternative minimal cells, we uncover an explanation for the unexpected fact that elimination of inhibitory phosphorylation of Cdk is benign in these strains while it strongly affects normal cells. Furthermore, in the strain without inhibitory phosphorylation of the fusion protein, the distribution of cell size at division is unusually broad, an observation that is accounted for by stochastic simulations of the model. Our approach provides novel insights into the organization and quantitative regulation of wild type cell cycle progression. In particular, it leads us to propose a new mechanistic model for the phenomenon of mitotic catastrophe, relying on a combination of unregulated, multi-cyclin-dependent Cdk activities.

  8. Refined life-cycle assessment of polymer solar cells

    DEFF Research Database (Denmark)

    Lenzmann, F.; Kroon, J.; Andriessen, R.

    2011-01-01

    A refined life-cycle assessment of polymer solar cells is presented with a focus on critical components, i.e. the transparent conductive ITO layer and the encapsulation components. This present analysis gives a comprehensive sketch of the full environmental potential of polymer-OPV in comparison...

  9. Maid (GCIP) is involved in cell cycle control of hepatocytes

    DEFF Research Database (Denmark)

    Sonnenberg-Riethmacher, Eva; Wüstefeld, Torsten; Miehe, Michaela;

    2007-01-01

    . Therefore, we studied the role of Maid during cell cycle progression after partial hepatectomy (PH). Lack of Maid expression after PH was associated with a delay in G1/S-phase progression as evidenced by delayed cyclinA expression and DNA replication in Maid-deficient mice. However, at later time points...

  10. Cycle life status of SAFT VOS nickel-cadmium cells

    Science.gov (United States)

    Goualard, Jacques

    1993-01-01

    The SAFT prismatic VOS Ni-Cd cells have been flown in geosynchronous orbit since 1977 and in low earth orbit since 1983. Parallel cycling tests are performed by several space agencies in order to determine the cycle life for a wide range of temperature and depth of discharge (DOD). In low Earth orbit (LEO), the ELAN program is conducted on 24 Ah cells by CNES and ESA at the European Battery Test Center at temperatures ranging from 0 to 27 C and DOD from 10 to 40 percent. Data are presented up to 37,000 cycles. One pack (X-80) has achieved 49,000 cycles at 10 C and 23 percent DOD. The geosynchronous orbit simulation of a high DOD test is conducted by ESA on 3 batteries at 10 C and 70, 90, and 100 percent DOD. Thirty-one eclipse seasons are completed, and no signs of degradation have been found. The Air Force test at CRANE on 24 Ah and 40 Ah cells at 20 C and 80 percent DOD has achieved 19 shadow periods. Life expectancy is discussed. The VOS cell technology could be used for the following: (1) in geosynchronous conditions--15 yrs at 10-15 C and 80 percent DOD; and (2) in low earth orbit--10 yrs at 5-15 C and 25-30 percent DOD.

  11. Complex scheme of company image management on the stages of its life cycle

    OpenAIRE

    A.V. Kolodka

    2014-01-01

    The aim of the article. The aim of the article is to create a common integrated circuit image management during a life-cycle of enterprise based on internal and external economic conditions. The results of the analysis. In the article the general scheme of image management during a life-cycle of enterprise based on internal and external economic conditions is formed. There is no single view on the question of forming general concepts and approaches to image building. That threatens making ...

  12. Visualizing cell-cycle kinetics after hypoxia/reoxygenation in HeLa cells expressing fluorescent ubiquitination-based cell cycle indicator (Fucci).

    Science.gov (United States)

    Goto, Tatsuaki; Kaida, Atsushi; Miura, Masahiko

    2015-12-10

    Hypoxia induces G1 arrest in many cancer cell types. Tumor cells are often exposed to hypoxia/reoxygenation, especially under acute hypoxic conditions in vivo. In this study, we investigated cell-cycle kinetics and clonogenic survival after hypoxia/reoxygenation in HeLa cells expressing fluorescent ubiquitination-based cell cycle indicator (Fucci). Hypoxic treatment halted cell-cycle progression during mid-S to G2 phase, as determined by the cell cycle-regulated E3 ligase activities of SCF(Skp2) and APC/C(Cdh1), which are regulators of the Fucci probes; however, the DNA content of the arrested cells was equivalent to that in G1 phase. After reoxygenation, time-lapse imaging and DNA content analysis revealed that all cells reached G2 phase, and that Fucci fluorescence was distinctly separated into two fractions 24h after reoxygenation: red cells that released from G2 arrest after repairing DNA double-strand breaks (DSBs) exhibited higher clonogenic survival, whereas most cells that stayed green contained many DSBs and exhibited lower survival. We conclude that hypoxia disrupts coordination of DNA synthesis and E3 ligase activities associated with cell-cycle progression, and that DSB repair could greatly influence cell-cycle kinetics and clonogenic survival after hypoxia/reoxygenation.

  13. Multi-Bed Multi-Stage Adsorption Refrigeration Cycle-Reducing Driving Heat Source Temperature

    Science.gov (United States)

    Alam, K. C. Amanul; Akahira, Akira; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao; Saha, Bidyut Baran; Koyama, Shigeru; Ng, Kim Choon; Chua, Hui Tong

    The study aims at designing a multi-bed multi-stage adsorption chiller that can be driven by waste heat at near ambient temperature. The chiller is designed such a way that it can be switched into different modes depending on the driving heat source temperature. Stage regeneration techniques have been applied to operate the chiller by relatively low temperature heat source. Driving heat source temperature is validated by simulated data and the performances obtained from different modes are compared. In terms of COP (Coefficient of performance),the chiller shows best performance in conventional single-stage mode for driving heat source temperature greater than 60°C, two stage mode for driving source temperature between 42 and 60°C,in three-stage mode for driving source temperature less than 42°C. In terms of cooling capacity, it shows the best performance in single-stage mode for heat source temperature greater than 70°C. The mass recovery process in single-stage mode is also examined. It is seen that the mass recovery process improve cooling capacity significantly, specially for the low regenerating temperature region.

  14. Regional nodal relapse in surgically staged Merkel cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Hoeller, Ulrike; Mueller, Thomas; Schubert, Tina; Budach, Volker; Ghadjar, Pirus [Charite Universitaetsmedizin Berlin, Department of Radiation Oncology, Berlin (Germany); Brenner, Winfried [Charite Universitaetsmedizin Berlin, Department of Nuclear Medicine, Berlin (Germany); Kiecker, Felix [Charite Universitaetsmedizin Berlin, Department of Dermatology, Berlin (Germany); Schicke, Bernd [Tumor Center Berlin, Berlin (Germany); Haase, Oliver [Charite Universitaetsmedizin Berlin, Department of Surgery, Berlin (Germany)

    2014-10-08

    The nodal relapse pattern of surgically staged Merkel cell carcinoma (MCC) with/without elective nodal radiotherapy (RT) was studied in a single institution. A total of 51 patients with MCC, 33 % UICC stage I, 14 % II, 53 % III (4 lymph node metastases of unknown primary) were eligible. All patients had surgical staging: 23 patients sentinel node biopsy (SNB), 22 patients SNB followed by lymphadenectomy (LAD) and 6 patients LAD. In all, 94 % of the primary tumors (PT) were completely resected; 57 % of patients received RT, 51 % of known PT sites, 33 % (8/24 patients) regional RT to snN0 nodes and 68 % (17/27 patients) to pN+ nodes, mean reference dose 51.5 and 50 Gy, respectively. Mean follow-up was 6 years (range 2-14 years). A total of 22 % (11/51) patients developed regional relapses (RR); the 5-year RR rate was 27 %. In snN0 sites (stage I/II), relapse occurred in 5 of 14 nonirradiated vs. none of 8 irradiated sites (p = 0.054), resulting in a 5-year RR rate of 33 % versus 0 % (p = 0.16). The crude RR rate was lower in stage I (12 %, 2/17 patients) than for stage II (43 %, 3/7 patients). In stage III (pN+), RR appeared to be less frequent in irradiated sites (18 %, 3/14 patients) compared with nonirradiated sites (33 %, 3/10 patients, p = 0.45) with 5-year RR rates of 23 % vs. 34 %, respectively. Our data suggest that adjuvant nodal RT plays a major role even if the sentinel nodes were negative. Adjuvant RT of the lymph nodes in patients with stage IIa tumors and RT after LAD in stage III tumors is proposed and should be evaluated prospectively. (orig.) [German] Untersucht wurde das regionaere Rezidivmuster des Merkelzell-Karzinoms (MCC) nach chirurgischem Staging und stadienadaptierter Therapie. Eingeschlossen wurden 51 Patienten mit lokalisiertem MCC: 33 % hatten UICC-Stadium-I-, 14 % -II-, 53 % -III-Tumoren (davon 4 Lymphknotenmetastasen eines unbekannten Primaertumors). Alle Patienten erhielten ein chirurgisches Staging: 23 Waechterlymphknotenbiopsien (SNB

  15. Effect of staurosporine on cycle of human gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Min-Wen Ha; Ke-Zuo Hou; Yun-Peng Liu; Yuan Yuan

    2004-01-01

    AIM: To study the effect of staurosporine (ST) on the cell cycle of human gastriccancer cell lines MGC803 and SGC7901.METHODS: Cell proliferation was evaluated by trypan blue dye exclusion method. Apoptotic morphology was observed under a transmission electron microscope. Changes of cell cycle and apoptotic peaks of cells were determined by flow cytometry. Expression of p21WAFI gene was examined using immunohistochemistry and RT-PCR.RESULTS: The growth of MGC803 and SGC7901 cells was inhibited by ST. The inhibitory concentrations against 50% cells (IC50) at 24 h and 48 h were 54 ng/ml and 23 ng/ml for MlGC803, and 61 ng/ml and 37 ng/ml for SGC7901. Typical apoptotic bodies and apoptotic peaks were observed 24 hafter cells were treated wth ST at a concentration of 200ng/ml. The percentage of cells at G0/G1 phase was decreased and that of cells at G2/M was increased significantly in the group treated wth ST at the concentrations of 40ng/ml,60 ng/ml, 100 ng/ml for 24 h, compared with the control group (P<0.01). The expression levels of p21WAFI gene in both MGC803 and SGC7901 cells were markedly up-regulated after treatment with ST.CONCLUSION: ST can cause arrest of gastric cancer cells at G2/M phase, which may be one of the mechanisms that inhibit cell proliferation and cause apoptosis in these cells.Effect of ST on cells at G2/M phase may be attributed to the up-regulattion of p21WAFI gene.

  16. The control system of the ecological hybrid two stages refrigerating cycle

    Directory of Open Access Journals (Sweden)

    Cyklis Piotr

    2016-01-01

    Full Text Available The compression anticlockwise cycle is mostly used for refrigeration. However due to the environmental regulations, the use of classic refrigerants: F-gases is limited by international agreements. Therefore the combined compression-adsorption hybrid cycle with natural liquids: water/carbon dioxide working as the energy carriers is a promising solution. This allows to utilize the solar or waste energy for the refrigeration purpose. In this paper application of the solar collectors as the energy source for the adsorption cycle, coupled with the low temperature (LT refrigerating carbon dioxide compression cycle is shown. The control of the system is an essential issue to reduce the electric power consumption. The control of the solar heat supply and water sprayed cooling tower, for the adsorption cycle re-cooling, is presented in this paper. The designed control system and algorithm is related to the LT compression cycle, which operates according to the need of cold for the refrigeration chamber. The results of the laboratory investigations of the full system, showing the reduction of the energy consumption and maximum utilization of the solar heat for different control methods are presented.

  17. Life cycle sustainability of solid oxide fuel cells: From methodological aspects to system implications

    Science.gov (United States)

    Mehmeti, Andi; McPhail, Stephen J.; Pumiglia, Davide; Carlini, Maurizio

    2016-09-01

    This study reviews the status of life cycle assessment (LCA) of Solid Oxide Fuel Cells (SOFCs) and methodological aspects, communicates SOFC environmental performance, and compares the environmental performance with competing power production technologies using a life cycle perspective. Results indicate that power generation using SOFCs can make a significant contribution to the aspired-to greener energy future. Despite superior environmental performance, empirical studies indicate that economic performance is predominantly the highest-ranked criterion in the decision making process. Future LCA studies should attempt to employ comprehensive dynamic multi-criteria environmental impact analysis coupled with economic aspects, to allow a robust comparison of results. A methodology framework is proposed to achieve simultaneously ambitious socio-economic and environmental objectives considering all life cycle stages and their impacts.

  18. Observations on Sambar Rusa unicolor (Cetartiodactyla: Cervidae stags during hard and velvet stages of antler cycle in captivity

    Directory of Open Access Journals (Sweden)

    V.V. Savanth

    2011-10-01

    Full Text Available This research was carried out at the State Museum and Zoo, Thrissur, Kerala, India from June to October, 2009. The objective was to observe and record the physical and behavioural changes in Sambar Deer Rusa unicolor stags linked to their territorial display during various stages of the breeding cycle. In total, there were 70 Sambar in the enclosure, at the commencement of the study, of which 22 were males including 16 adult stags. Six stags were selected for the study. Observations were made by focal animal sampling technique. An ethogram was devised and behavioural patterns were indicated on it. The behavioural score derived from the ethogram was significantly higher in stags in their hard antler stage when compared to the stags in the velvet stage. The stags in the hard antler stage were more massive, had bigger antlers, darker coat colour, thicker neck, larger scrotum and maintained a larger ‘harem’ in comparison to the velvet stage stags which preferred a rather subdued life. The most dominant stags in the hard antler stage had up to 17 female members in his territory. As the stags in velvet entered the rut season, the dominant stag had up to 19 females in his territory. The study is expected to be useful to evolve strategies to identify and reduce a few males not contributing in breeding in any particular enclosure and thus curtail expenses in management of cervids in captivity.

  19. Cell-cycle quiescence maintains Caenorhabditis elegans germline stem cells independent of GLP-1/Notch.

    Science.gov (United States)

    Seidel, Hannah S; Kimble, Judith

    2015-11-09

    Many types of adult stem cells exist in a state of cell-cycle quiescence, yet it has remained unclear whether quiescence plays a role in maintaining the stem cell fate. Here we establish the adult germline of Caenorhabditis elegans as a model for facultative stem cell quiescence. We find that mitotically dividing germ cells--including germline stem cells--become quiescent in the absence of food. This quiescence is characterized by a slowing of S phase, a block to M-phase entry, and the ability to re-enter M phase rapidly in response to re-feeding. Further, we demonstrate that cell-cycle quiescence alters the genetic requirements for stem cell maintenance: The signaling pathway required for stem cell maintenance under fed conditions--GLP-1/Notch signaling--becomes dispensable under conditions of quiescence. Thus, cell-cycle quiescence can itself maintain stem cells, independent of the signaling pathway otherwise essential for such maintenance.

  20. Identification of new morphological and life-cycle stages of Cochlosoma anatis and experimental transmission using pseudocyst.

    Science.gov (United States)

    Evans, Nicholas P; Evans, Robert D; Fitz-Coy, Steve; Pierson, F William; Robertson, John L; Lindsay, David S

    2006-03-01

    Cochlosoma anatis is a flagellated intestinal parasite that infects a variety of avian species. C. anatis infections have been associated with decreased weight gain and increased morbidity and mortality. Conditions favoring the growth of this organism in birds are current pathogenic intestinal infections and/or young age. There is little data describing the life cycle of this parasite. In this study, electron microscopy images are presented that document longitudinal binary fission of the trophozoite stage and outline the events of pseudocyst formation, which includes a rounding stage. Evidence provided here indicates that the pseudocyst stage may be a mechanism for transmission of this organism. The observations reported here provide additional evidence of homology between Cochlosoma and members of the trichomonad order.

  1. Electron-microscopic characteristics of neuroendocrine neurons in the amygdaloid body of the brain in male rats and female rats at different stages of the estral cycle.

    Science.gov (United States)

    Akhmadeev, A V; Kalimullina, L B

    2008-01-01

    The ultrastructural features of neuroendocrine neurons in the dorsomedial nucleus (DMN) of the amygdaloid body of the brain - one of the major zones of sexual dimorphism - in 12 Wistar rats weighing 250-300 g were studied in three males and nine females at different stages of the estral cycle. On the basis of ultrastructural characteristics, analysis of the functional states of an average of 50 DMN neurons were studied in each animal. A morphofunctional classification reflecting hormone-dependent variations in neuron activity is proposed. DMN neurons were found to be in different structural-functional states, which could be classified as the states of rest, moderate activity, elevated activity, tension (maximal activity), decreased activity (types 1 and 2, depending on prior history), return to the initial state, and apoptosis. At the estrus stage, there was a predominance of neurons in the states of elevated activity (40% of all cells) and maximal activity (26%). At the metestrus stage, neurons in the state of decreased activity type 1 (with increased nuclear heterochromatin content) predominated (30% of cells), while 25% and 20% of cells were in the states of maximal activity and elevated activity respectively. In diestrus, neurons in the resting state, in moderate and elevated activity, in maximal activity, and in decreased activity type 1 were present in essentially identical proportions (18%, 21%, 18%, 20%, and 16% respectively). In males, 35% and 22% of neurons were in the states of elevated and maximal activity respectively. Neuron death was seen only in males.

  2. Akt1 intramitochondrial cycling is a crucial step in the redox modulation of cell cycle progression.

    Directory of Open Access Journals (Sweden)

    Valeria Gabriela Antico Arciuch

    Full Text Available Akt is a serine/threonine kinase involved in cell proliferation, apoptosis, and glucose metabolism. Akt is differentially activated by growth factors and oxidative stress by sequential phosphorylation of Ser(473 by mTORC2 and Thr(308 by PDK1. On these bases, we investigated the mechanistic connection of H(2O(2 yield, mitochondrial activation of Akt1 and cell cycle progression in NIH/3T3 cell line with confocal microscopy, in vivo imaging, and directed mutagenesis. We demonstrate that modulation by H(2O(2 entails the entrance of cytosolic P-Akt1 Ser(473 to mitochondria, where it is further phosphorylated at Thr(308 by constitutive PDK1. Phosphorylation of Thr(308 in mitochondria determines Akt1 passage to nuclei and triggers genomic post-translational mechanisms for cell proliferation. At high H(2O(2, Akt1-PDK1 association is disrupted and P-Akt1 Ser(473 accumulates in mitochondria in detriment to nuclear translocation; accordingly, Akt1 T308A is retained in mitochondria. Low Akt1 activity increases cytochrome c release to cytosol leading to apoptosis. As assessed by mass spectra, differential H(2O(2 effects on Akt1-PDK interaction depend on the selective oxidation of Cys(310 to sulfenic or cysteic acids. These results indicate that Akt1 intramitochondrial-cycling is central for redox modulation of cell fate.

  3. Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones

    Science.gov (United States)

    Gil-Sotres, F.; Miralles, I.; Canton-Castilla, Y.; Domingo, F.; Leiros, M. C.; Trasar-Cepeda, C.

    2012-04-01

    Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones I. Miralles1, F. Gil-Sotres2, Y. Cantón-Castilla3, F. Domingo1, M.C. Leirós2, C. Trasar-Cepeda4 1 Experimental Estation of Arid Zones (CSIC), E-04230 La Cañada de San Urbano, Almería, Spain. 2 Departamento Edafología y Química Agrícola, Grupo de Evaluación de la Calidad del Suelo, Unidad Asociada CSIC, Facultad de Farmacia, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain. 3 University of Almería, Departamento de Edafología y Química Agrícola, E-04230-La Cañada de San Urbano, Almería, Spain. 4 Departamento Bioquímica del Suelo, IIAG-CSIC, Apartado 122, E-15708 Santiago de Compostela, Spain. Crusts (BSCs) are formed by a close association between soil particles and cyanobacteria, algae, lichens, bryophytes and microfungi in varying proportions. Their habitat is within or immediately on top of the uppermost millimetres of the soil and are the predominant surface cover in arid and semiarid zones. Among the diverse functions developed by BSCs in the ecosystem (hydrology, erosion, soil properties, etc.), one of the most important is its role in nutrient cycling. Within arid and semiarid environments, BSCs have been termed 'mantles of fertility' being considered hotspots of biogeochemical inputs, fixing C, N and P above- and below-ground. However, there are differences in N and C fixation rates between BSCs types. Early successional BSCs, dominated by cyanobacterial species, fix lower quantities of C and N than mature BSCs dominated by lichens. Although the positive effects of BSCs on biogeochemical soil cycles are widely accepted, no previous studies have evaluated the activities of the enzymes involved in C, N and P cycles of BSCs and how they are affected by the successional stage of the BSC. In this work, performed in the Tabernas desert (SE Spain), we studied the hydrolase enzymes

  4. Phase resetting reveals network dynamics underlying a bacterial cell cycle.

    Directory of Open Access Journals (Sweden)

    Yihan Lin

    Full Text Available Genomic and proteomic methods yield networks of biological regulatory interactions but do not provide direct insight into how those interactions are organized into functional modules, or how information flows from one module to another. In this work we introduce an approach that provides this complementary information and apply it to the bacterium Caulobacter crescentus, a paradigm for cell-cycle control. Operationally, we use an inducible promoter to express the essential transcriptional regulatory gene ctrA in a periodic, pulsed fashion. This chemical perturbation causes the population of cells to divide synchronously, and we use the resulting advance or delay of the division times of single cells to construct a phase resetting curve. We find that delay is strongly favored over advance. This finding is surprising since it does not follow from the temporal expression profile of CtrA and, in turn, simulations of existing network models. We propose a phenomenological model that suggests that the cell-cycle network comprises two distinct functional modules that oscillate autonomously and couple in a highly asymmetric fashion. These features collectively provide a new mechanism for tight temporal control of the cell cycle in C. crescentus. We discuss how the procedure can serve as the basis for a general approach for probing network dynamics, which we term chemical perturbation spectroscopy (CPS.

  5. Autophagy and the Cell Cycle: A Complex Landscape

    Science.gov (United States)

    Mathiassen, Søs Grønbæk; De Zio, Daniela; Cecconi, Francesco

    2017-01-01

    Autophagy is a self-degradation pathway, in which cytoplasmic material is sequestered in double-membrane vesicles and delivered to the lysosome for degradation. Under basal conditions, autophagy plays a homeostatic function. However, in response to various stresses, the pathway can be further induced to mediate cytoprotection. Defective autophagy has been linked to a number of human pathologies, including neoplastic transformation, even though autophagy can also sustain the growth of tumor cells in certain contexts. In recent years, a considerable correlation has emerged between autophagy induction and stress-related cell-cycle responses, as well as unexpected roles for autophagy factors and selective autophagic degradation in the process of cell division. These advances have obvious implications for our understanding of the intricate relationship between autophagy and cancer. In this review, we will discuss our current knowledge of the reciprocal regulation connecting the autophagy pathway and cell-cycle progression. Furthermore, key findings involving nonautophagic functions for autophagy-related factors in cell-cycle regulation will be addressed.

  6. Cell-cycle analyses using thymidine analogues in fission yeast.

    Directory of Open Access Journals (Sweden)

    Silje Anda

    Full Text Available Thymidine analogues are powerful tools when studying DNA synthesis including DNA replication, repair and recombination. However, these analogues have been reported to have severe effects on cell-cycle progression and growth, the very processes being investigated in most of these studies. Here, we have analyzed the effects of 5-ethynyl-2'-deoxyuridine (EdU and 5-Chloro-2'-deoxyuridine (CldU using fission yeast cells and optimized the labelling procedure. We find that both analogues affect the cell cycle, but that the effects can be mitigated by using the appropriate analogue, short pulses of labelling and low concentrations. In addition, we report sequential labelling of two consecutive S phases using EdU and 5-bromo-2'-deoxyuridine (BrdU. Furthermore, we show that detection of replicative DNA synthesis is much more sensitive than DNA-measurements by flow cytometry.

  7. Cell-cycle analyses using thymidine analogues in fission yeast.

    Science.gov (United States)

    Anda, Silje; Boye, Erik; Grallert, Beata

    2014-01-01

    Thymidine analogues are powerful tools when studying DNA synthesis including DNA replication, repair and recombination. However, these analogues have been reported to have severe effects on cell-cycle progression and growth, the very processes being investigated in most of these studies. Here, we have analyzed the effects of 5-ethynyl-2'-deoxyuridine (EdU) and 5-Chloro-2'-deoxyuridine (CldU) using fission yeast cells and optimized the labelling procedure. We find that both analogues affect the cell cycle, but that the effects can be mitigated by using the appropriate analogue, short pulses of labelling and low concentrations. In addition, we report sequential labelling of two consecutive S phases using EdU and 5-bromo-2'-deoxyuridine (BrdU). Furthermore, we show that detection of replicative DNA synthesis is much more sensitive than DNA-measurements by flow cytometry.

  8. Cellular distribution of cell cycle-related molecules in the renal tubules of rats treated with renal carcinogens for 28 days: relationship between cell cycle aberration and carcinogenesis.

    Science.gov (United States)

    Taniai, Eriko; Hayashi, Hitomi; Yafune, Atsunori; Watanabe, Maiko; Akane, Hirotoshi; Suzuki, Kazuhiko; Mitsumori, Kunitoshi; Shibutani, Makoto

    2012-09-01

    Some renal carcinogens can induce karyomegaly, which reflects aberrant cell division in the renal tubules, from the early stages of exposure. To clarify the cell cycle-related changes during the early stages of renal carcinogenesis, we performed immunohistochemical analysis of tubular cells in male F344 rats treated with carcinogenic doses of representative renal carcinogens for 28 days. For this purpose, the karyomegaly-inducing carcinogens ochratoxin A (OTA), ferric nitrilotriacetic acid, and monuron, and the non-karyomegaly-inducing carcinogens tris(2-chloroethyl) phosphate and potassium bromate were examined. For comparison, a karyomegaly-inducing non-carcinogen, p-nitrobenzoic acid, and a non-carcinogenic non-karyomegaly-inducing renal toxicant, acetaminophen, were also examined. The outer stripe of the outer medulla (OSOM) and the cortex + OSOM were subjected to morphometric analysis of immunoreactive proximal tubular cells. Renal carcinogens, irrespective of their karyomegaly-inducing potential, increased proximal tubular cell proliferation accompanied by an increase in topoisomerase IIα-immunoreactive cells, suggesting a reflection of cell proliferation. Karyomegaly-inducing carcinogens increased nuclear Cdc2-, γH2AX-, and phosphorylated Chk2-immunoreactive cells in both areas, the former two acting in response to DNA damage and the latter one suggestive of sustained G₂. OTA, an OSOM-targeting carcinogen, could easily be distinguished from untreated controls and non-carcinogens by evaluation of molecules responding to DNA damage and G₂/M transition in the OSOM. Thus, all renal carcinogens examined facilitated proximal tubular proliferation by repeated short-term treatment. Among these, karyomegaly-inducing carcinogens may cause DNA damage and G₂ arrest in the target tubular cells.

  9. 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.

  10. Relation Between the Cell Volume and the Cell Cycle Dynamics in Mammalian cell

    Science.gov (United States)

    Magno, A. C. G.; Oliveira, I. L.; Hauck, J. V. S.

    2016-08-01

    The main goal of this work is to add and analyze an equation that represents the volume in a dynamical model of the mammalian cell cycle proposed by Gérard and Goldbeter (2011) [1]. The cell division occurs when the cyclinB/Cdkl complex is totally degraded (Tyson and Novak, 2011)[2] and it reaches a minimum value. At this point, the cell is divided into two newborn daughter cells and each one will contain the half of the cytoplasmic content of the mother cell. The equations of our base model are only valid if the cell volume, where the reactions occur, is constant. Whether the cell volume is not constant, that is, the rate of change of its volume with respect to time is explicitly taken into account in the mathematical model, then the equations of the original model are no longer valid. Therefore, every equations were modified from the mass conservation principle for considering a volume that changes with time. Through this approach, the cell volume affects all model variables. Two different dynamic simulation methods were accomplished: deterministic and stochastic. In the stochastic simulation, the volume affects every model's parameters which have molar unit, whereas in the deterministic one, it is incorporated into the differential equations. In deterministic simulation, the biochemical species may be in concentration units, while in stochastic simulation such species must be converted to number of molecules which are directly proportional to the cell volume. In an effort to understand the influence of the new equation a stability analysis was performed. This elucidates how the growth factor impacts the stability of the model's limit cycles. In conclusion, a more precise model, in comparison to the base model, was created for the cell cycle as it now takes into consideration the cell volume variation

  11. The improvement of approaches to marketing testing of ecological innovative products in the stages of innovative cycle

    Directory of Open Access Journals (Sweden)

    Ye.I. Nagornyi

    2013-12-01

    Full Text Available The aim of the article. The aim of the article is theoretical justification and improvement of approaches to marketing testing of ecological innovative production in the stages of innovative cycle, and the sequence of decision-making procedures on its readiness to entry into the market by results of testing. The results of the analysis. Launch of the ecological innovative products on the market and providing its passage through the stages of the innovative cycle requires continuous and high-quality information and analytical support. This support can be reached as a result of marketing testing procedures. The analysis of the existing evolutionary approaches to marketing testing procedure allowed finding out that they are not deprived disadvantages. Separate theoretical and methodological aspects of marketing testing of innovative products are analyzed in the scientific literature. But issues of marketing testing of ecological innovations and introduction of the given procedure at early stages of an innovative cycle are insufficiently investigated. Author's definition of marketing testing concept is reduced to complex process of a choice, an assessment and selection of a subject of the marketing approbation which is carried out at each stage of product development, for stage-by-stage and general definition of progress level of innovative production in the market, and also for the analysis of its readiness degree to entry the market. As a subject of approbation can be used: directions of innovative development of the enterprise, sources of ideas, ideas, concepts, prototypes of new products and their market attributes, and also marketing strategy as a whole. The types of testing taking place at each stage of an innovative cycle of development of goods are allocated in research. Problems (tasks that procedure of marketing testing solves are researched and methodological approaches to its implementation are suggested. Marketing testing is a complex

  12. Cell cycle-arrested tumor cells exhibit increased sensitivity towards TRAIL-induced apoptosis

    OpenAIRE

    Ehrhardt, H.; Wachter, F; Grunert, M.; Jeremias, I

    2013-01-01

    Resting tumor cells represent a huge challenge during anticancer therapy due to their increased treatment resistance. TNF-related apoptosis-inducing ligand (TRAIL) is a putative future anticancer drug, currently in phases I and II clinical studies. We recently showed that TRAIL is able to target leukemia stem cell surrogates. Here, we tested the ability of TRAIL to target cell cycle-arrested tumor cells. Cell cycle arrest was induced in tumor cell lines and xenografted tumor cells in G0, G1 o...

  13. Serum starvation and thymidine double blocking achieved efficient cell cycle synchronization and altered the expression of p27, p53, bcl-2 in canine breast cancer cells.

    Science.gov (United States)

    Tong, Jinjin; Sun, Dongdong; Yang, Chao; Wang, Yingxue; Sun, Sichao; Li, Qing; Bao, Jun; Liu, Yun

    2016-04-01

    Cell synchronization is an approach to obtain cell populations of the same stage, which is a prerequisite to studying the regulation of cell cycle progression in vivo. Serum starvation and thymidine double blocking (TdR) are two important practices in studying cell cycle synchronization. However, their effects on canine cancer cells as well as the regulatory mechanisms by these two methods are poorly understood. In this study, we determined the optimum conditions of serum starvation and TdR and their effects on cell cycle synchronization. We further explored the involvement of PI3K/Akt signaling pathway in the cell cycle synchronization by investigating the expression of three key genes (p27, p53 and bcl-2). Serum starvation resulted in a reversible cell cycle arrest and synchronously progress through G0/G1. The highest percentage of CHMm cells (87.47%) in G0/G1 stage was obtained after 42 h incubation with 0.5% fetal bovine serum (FBS). TdR double blocking could arrest 98.9% of CHMm cells in G1/S phase (0 h of release), and could arrest 93.74% of CHMm cells in S phase after 4h of release. We also found that the p27, p53, bcl-2 genes were most highly expressed in G0/G1 phase. Our current work revealed that serum starvation and TdR methods could achieve sufficient synchronization of CHMm cells. Moreover, the expression of p27, p53 and bcl-2 genes was related to cyclical movements and apoptosis. Our results will provide a new insight into cell cycle regulation and reprogramming of canine cancer cells induced by serum starvation and TdR blocking.

  14. Cellular capacities for high-light acclimation and changing lipid profiles across life cycle stages of the green alga Haematococcus pluvialis.

    Directory of Open Access Journals (Sweden)

    Baobei Wang

    Full Text Available The unicellular microalga Haematococcus pluvialis has emerged as a promising biomass feedstock for the ketocarotenoid astaxanthin and neutral lipid triacylglycerol. Motile flagellates, resting palmella cells, and cysts are the major life cycle stages of H. pluvialis. Fast-growing motile cells are usually used to induce astaxanthin and triacylglycerol biosynthesis under stress conditions (high light or nutrient starvation; however, productivity of biomass and bioproducts are compromised due to the susceptibility of motile cells to stress. This study revealed that the Photosystem II (PSII reaction center D1 protein, the manganese-stabilizing protein PsbO, and several major membrane glycerolipids (particularly for chloroplast membrane lipids monogalactosyldiacylglycerol and phosphatidylglycerol, decreased dramatically in motile cells under high light (HL. In contrast, palmella cells, which are transformed from motile cells after an extended period of time under favorable growth conditions, have developed multiple protective mechanisms--including reduction in chloroplast membrane lipids content, downplay of linear photosynthetic electron transport, and activating nonphotochemical quenching mechanisms--while accumulating triacylglycerol. Consequently, the membrane lipids and PSII proteins (D1 and PsbO remained relatively stable in palmella cells subjected to HL. Introducing palmella instead of motile cells to stress conditions may greatly increase astaxanthin and lipid production in H. pluvialis culture.

  15. Modeling circadian clock-cell cycle interaction effects on cell population growth rates.

    Science.gov (United States)

    El Cheikh, R; Bernard, S; El Khatib, N

    2014-12-21

    The circadian clock and the cell cycle are two tightly coupled oscillators. Recent analytical studies have shown counter-intuitive effects of circadian gating of the cell cycle on growth rates of proliferating cells which cannot be explained by a molecular model or a population model alone. In this work, we present a combined molecular-population model that studies how coupling the circadian clock to the cell cycle, through the protein WEE1, affects a proliferating cell population. We show that the cell cycle can entrain to the circadian clock with different rational period ratios and characterize multiple domains of entrainment. We show that coupling increases the growth rate for autonomous periods of the cell cycle around 24 h and above 48 h. We study the effect of mutation of circadian genes on the growth rate of cells and show that disruption of the circadian clock can lead to abnormal proliferation. Particularly, we show that Cry 1, Cry 2 mutations decrease the growth rate of cells, Per 2 mutation enhances it and Bmal 1 knockout increases it for autonomous periods of the cell cycle less than 21 h and decreases it elsewhere. Combining a molecular model to a population model offers new insight on the influence of the circadian clock on the growth of a cell population. This can help chronotherapy which takes benefits of physiological rhythms to improve anti-cancer efficacy and tolerance to drugs by administering treatments at a specific time of the day.

  16. Life cycle and morphology of development stages of Physocephalus dromedarii (Nematoda:Spirocercidae)

    Institute of Scientific and Technical Information of China (English)

    Rolf Karl Schuster; Saritha Sivakumar; J ¨org Kinne

    2016-01-01

    Objective: To study the development of Physocephalus dromedarii (P. dromedarii) in the final host. Methods: For this, 5 adult dromedaries were orally infected with third larval stages of P. dromedarii obtained from naturally infected scarab beetles (Scarabaeus cristatus). The camels were necropsied 14, 42, 70, 84 and 280 days after infection and their abomasi were examined for the presence of nematodes. Results: Early 4th stage larva occurred already 2 weeks after infection. They were still in the sheet of the 3rd stage larva. Six weeks after infection, the nematodes became juvenile male and female adults measuring 9 and 10 mm, respectively. Their size doubled at 10 weeks post infection and patency was reached at 12 weeks. P. dromedarii was still present in the camel that was examined 40 weeks after infection. Conclusions: As a result of experimental infection of the natural host, the determined prepatent period of P. dromedarii equalled 12 weeks.

  17. Stochastic Real-World Drive Cycle Generation Based on a Two Stage Markov Chain Approach

    NARCIS (Netherlands)

    Balau, A.E.; Kooijman, D.; Vazquez Rodarte, I.; Ligterink, N.

    2015-01-01

    This paper presents a methodology and tool that stochastically generates drive cycles based on measured data, with the purpose of testing and benchmarking light duty vehicles in a simulation environment or on a test-bench. The WLTP database, containing real world driving measurements, was used as in

  18. Methoxyamine, Pemetrexed Disodium, Cisplatin, and Radiation Therapy in Treating Patients With Stage IIIA-IV Non-small Cell Lung Cancer

    Science.gov (United States)

    2016-10-05

    Metastatic Malignant Neoplasm in the Brain; Stage IIIA Large Cell Lung Carcinoma; Stage IIIA Lung Adenocarcinoma; Stage IIIA Non-Small Cell Lung Cancer; Stage IIIB Large Cell Lung Carcinoma; Stage IIIB Lung Adenocarcinoma; Stage IIIB Non-Small Cell Lung Cancer; Stage IV Large Cell Lung Carcinoma; Stage IV Lung Adenocarcinoma; Stage IV Non-Small Cell Lung Cancer

  19. SAMHD1 controls cell cycle status, apoptosis and HIV-1 infection in monocytic THP-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Bonifati, Serena [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States); Daly, Michele B. [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); St Gelais, Corine; Kim, Sun Hee [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States); Hollenbaugh, Joseph A.; Shepard, Caitlin [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Kennedy, Edward M. [Department of Molecular Genetics and Microbiology, Duke University, Durham, NC (United States); Kim, Dong-Hyun [Department of Pharmacy, School of Pharmacy, Kyung-Hee University, Seoul (Korea, Republic of); Schinazi, Raymond F. [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Kim, Baek, E-mail: baek.kim@emory.edu [Center for Drug Discovery, Department of Pediatrics, School of Medicine, Emory University, Atlanta, GA (United States); Department of Pharmacy, School of Pharmacy, Kyung-Hee University, Seoul (Korea, Republic of); Wu, Li, E-mail: wu.840@osu.edu [Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH (United States)

    2016-08-15

    SAMHD1 limits HIV-1 infection in non-dividing myeloid cells by decreasing intracellular dNTP pools. HIV-1 restriction by SAMHD1 in these cells likely prevents activation of antiviral immune responses and modulates viral pathogenesis, thus highlighting a critical role of SAMHD1 in HIV-1 physiopathology. Here, we explored the function of SAMHD1 in regulating cell proliferation, cell cycle progression and apoptosis in monocytic THP-1 cells. Using the CRISPR/Cas9 technology, we generated THP-1 cells with stable SAMHD1 knockout. We found that silencing of SAMHD1 in cycling cells stimulates cell proliferation, redistributes cell cycle population in the G{sub 1}/G{sub 0} phase and reduces apoptosis. These alterations correlated with increased dNTP levels and more efficient HIV-1 infection in dividing SAMHD1 knockout cells relative to control. Our results suggest that SAMHD1, through its dNTPase activity, affects cell proliferation, cell cycle distribution and apoptosis, and emphasize a key role of SAMHD1 in the interplay between cell cycle regulation and HIV-1 infection.

  20. Boolean network model predicts cell cycle sequence of fission yeast.

    Directory of Open Access Journals (Sweden)

    Maria I Davidich

    Full Text Available A Boolean network model of the cell-cycle regulatory network of fission yeast (Schizosaccharomyces Pombe is constructed solely on the basis of the known biochemical interaction topology. Simulating the model in the computer faithfully reproduces the known activity sequence of regulatory proteins along the cell cycle of the living cell. Contrary to existing differential equation models, no parameters enter the model except the structure of the regulatory circuitry. The dynamical properties of the model indicate that the biological dynamical sequence is robustly implemented in the regulatory network, with the biological stationary state G1 corresponding to the dominant attractor in state space, and with the biological regulatory sequence being a strongly attractive trajectory. Comparing the fission yeast cell-cycle model to a similar model of the corresponding network in S. cerevisiae, a remarkable difference in circuitry, as well as dynamics is observed. While the latter operates in a strongly damped mode, driven by external excitation, the S. pombe network represents an auto-excited system with external damping.

  1. Does the Serum Metallothionein Level Reflect the Stage of Testicular Germ Cell Tumor?

    Science.gov (United States)

    Tariba, Blanka; Živković, Tanja; Filipović Marijić, Vlatka; Erk, Marijana; Gamulin, Marija; Pizent, Alica

    2016-04-01

    Increased levels of metallothionein (MT) have recently been found in the blood serum of men with newly diagnosed testicular germ cell tumors (TGCT). In light of previously published results, the aim of this study was to investigate the difference in serum MT levels among patients with different stages of TGCT and compare MT with commonly used markers (α-fetoprotein, β-human chorionic gonadotropin and lactate dehydrogenase). The concentration of total MT was determined in the serum of 25 men with TGCT (seminoma or non-seminoma) by differential pulse voltammetry. Serum samples were obtained prior to chemotherapy, after two cycles of chemotherapy and 1 year after chemotherapy. A statistically significant difference in MT levels in patients with different stages of TGCT was observed in the serum of patients with non-seminoma obtained before chemotherapy. Although not significant, an increase in serum MT levels commensurate with the disease stage increase was also observed in patients with seminomatous TGCT. The results indicate that, in combination with the existing markers, MT could be useful for the identification of the histological type of tumor and stage of the disease before biopsy diagnosis.

  2. Dissection of Cell Division Processes in the One Cell Stage Caenorhabditis elegans Embryo by Mutational Analysis

    OpenAIRE

    Gönczy, Pierre; Schnabel, Heinke; Kaletta, Titus; Amores, Ana Duran; Hyman, Tony; Schnabel, Ralf

    1999-01-01

    To identify novel components required for cell division processes in complex eukaryotes, we have undertaken an extensive mutational analysis in the one cell stage Caenorhabditis elegans embryo. The large size and optical properties of this cell permit observation of cell division processes with great detail in live specimens by simple differential interference contrast (DIC) microscopy. We have screened an extensive collection of maternal-effect embryonic lethal mutations on chromosome III wi...

  3. Tangeretin induces cell cycle arrest and apoptosis through upregulation of PTEN expression in glioma cells.

    Science.gov (United States)

    Ma, Li-Li; Wang, Da-Wei; Yu, Xu-Dong; Zhou, Yan-Ling

    2016-07-01

    Tangeretin (TANG), present in peel of citrus fruits, has been shown to various medicinal properties such as chemopreventive and neuroprotective. However, the chemopreventive effect of TANG on glioblastoma cells has not been examined. The present study was designed to explore the anticancer potential of TANG in glioblastoma cells and to investigate the related mechanism. Human glioblastoma U-87MG and LN-18 cells were treated with 45μM concentration of TANG and cell growth was measured by MTT assay. The cell cycle distribution and cell death were measured by flow cytometry. The expression of cell cycle and apoptosis related genes were analyzed by quantitative RT-PCR and western blot. The cells treated with TANG were significantly increased cell growth suppression and cell death effects than vehicle treated cells. Further, TANG treatment increases G2/M arrest and apoptosis by modulating PTEN and cell-cycle regulated genes such as cyclin-D and cdc-2 mRNA and protein expressions. Moreover, the ability of TANG to decrease cell growth and to induce cell death was compromised when PTEN was knockdown by siRNA. Taken together, the chemopreventive effect of TANG is associated with regulation of cell-cycle and apoptosis in glioblastoma, thereby attenuating glioblastoma cell growth. Hence, the present findings suggest that TANG may be a therapeutic agent for glioblastoma treatment.

  4. Thermodynamic Analysis of an Integrated Solid Oxide Fuel Cell Cycle with a Rankine Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2010-01-01

    Hybrid systems consisting of Solid Oxide Fuel Cells (SOFC) on the top of a Steam Turbine (ST) are investigated. The plants are fired by natural gas (NG). A desulfurization reactor removes the sulfur content in the fuel while a pre-reformer breaks down the heavier hydrocarbons. The pre-treated fuel...... enters then into the anode side of the SOFC. The remaining fuels after the SOFC stacks enter a burner for further burning. The off-gases are then used to produce steam for a Rankine cycle in a Heat Recovery Steam Generator (HRSG). Different system setups are suggested. Cyclic efficiencies up to 67......% are achieved which is considerably higher than the conventional Combined Cycles (CC). Both ASR (Adiabatic Steam Reformer) and CPO (Catalytic Partial Oxidation) fuel pre-reformer reactors are considered in this investigation....

  5. S-phase duration is the main target of cell cycle regulation in neural progenitors of developing ferret neocortex.

    Science.gov (United States)

    Turrero García, Miguel; Chang, YoonJeung; Arai, Yoko; Huttner, Wieland B

    2016-02-15

    The evolutionary expansion of the neocortex primarily reflects increases in abundance and proliferative capacity of cortical progenitors and in the length of the neurogenic period during development. Cell cycle parameters of neocortical progenitors are an important determinant of cortical development. The ferret (Mustela putorius furo), a gyrencephalic mammal, has gained increasing importance as a model for studying corticogenesis. Here, we have studied the abundance, proliferation, and cell cycle parameters of different neural progenitor types, defined by their differential expression of the transcription factors Pax6 and Tbr2, in the various germinal zones of developing ferret neocortex. We focused our analyses on postnatal day 1, a late stage of cortical neurogenesis when upper-layer neurons are produced. Based on cumulative 5-ethynyl-2'-deoxyuridine (EdU) labeling as well as Ki67 and proliferating cell nuclear antigen (PCNA) immunofluorescence, we determined the duration of the various cell cycle phases of the different neocortical progenitor subpopulations. Ferret neocortical progenitors were found to exhibit longer cell cycles than those of rodents and little variation in the duration of G1 among distinct progenitor types, also in contrast to rodents. Remarkably, the main difference in cell cycle parameters among the various progenitor types was the duration of S-phase, which became shorter as progenitors progressively changed transcription factor expression from patterns characteristic of self-renewal to those of neuron production. Hence, S-phase duration emerges as major target of cell cycle regulation in cortical progenitors of this gyrencephalic mammal.

  6. Differential expression and alternative splicing of cell cycle genes in imatinib-treated K562 cells.

    Science.gov (United States)

    Liu, Jing; Lin, Jin; Huang, Lin-Feng; Huang, Bo; Xu, Yan-Mei; Li, Jing; Wang, Yan; Zhang, Jing; Yang, Wei-Ming; Min, Qing-Hua; Wang, Xiao-Zhong

    2015-09-01

    Cancer progression often involves the disorder of the cell cycle, and a number of effective chemotherapeutic drugs have been shown to induce cell cycle arrest. The purpose of this study was to comprehensively investigate the effects of imatinib on the expression profile of cell cycle genes in the chronic myeloid leukemia (CML) K562 cell line. In addition, we also investigated alternative splicing of the cell cycle genes affected by imatinib, since an important relationship has been shown to exist between RNA splicing and cell cycle progression. Exon array analysis was performed using total RNA purified from normal and imatinib-treated K562 cells. We identified 185 differentially expressed genes and 277 alternative splicing events between the two cell groups. A detailed analysis by reverse transcription-PCR (RT-PCR) of key genes confirmed the experimental results of the exon array. These results suggested that treatment of K562 cells with imatinib shifts the expression and alternative splicing profiles of several cell cycle-related genes. Importantly, these findings may help improve imatinib treatment strategies in patients with CML and may be useful for imatinib resistance research and CML drug development.

  7. Lineage-specific interface proteins match up the cell cycle and differentiation in embryo stem cells

    DEFF Research Database (Denmark)

    Re, Angela; Workman, Christopher; Waldron, Levi;

    2014-01-01

    The shortage of molecular information on cell cycle changes along embryonic stem cell (ESC) differentiation prompts an in silico approach, which may provide a novel way to identify candidate genes or mechanisms acting in coordinating the two programs. We analyzed germ layer specific gene expression...... changes during the cell cycle and ESC differentiation by combining four human cell cycle transcriptome profiles with thirteen in vitro human ESC differentiation studies. To detect cross-talk mechanisms we then integrated the transcriptome data that displayed differential regulation with protein...... interaction data. A new class of non-transcriptionally regulated genes was identified, encoding proteins which interact systematically with proteins corresponding to genes regulated during the cell cycle or cell differentiation, and which therefore can be seen as interface proteins coordinating the two...

  8. Systematic identification of yeast cell cycle transcription factors using multiple data sources

    Directory of Open Access Journals (Sweden)

    Li Wen-Hsiung

    2008-12-01

    Full Text Available Abstract Background Eukaryotic cell cycle is a complex process and is precisely regulated at many levels. Many genes specific to the cell cycle are regulated transcriptionally and are expressed just before they are needed. To understand the cell cycle process, it is important to identify the cell cycle transcription factors (TFs that regulate the expression of cell cycle-regulated genes. Results We developed a method to identify cell cycle TFs in yeast by integrating current ChIP-chip, mutant, transcription factor binding site (TFBS, and cell cycle gene expression data. We identified 17 cell cycle TFs, 12 of which are known cell cycle TFs, while the remaining five (Ash1, Rlm1, Ste12, Stp1, Tec1 are putative novel cell cycle TFs. For each cell cycle TF, we assigned specific cell cycle phases in which the TF functions and identified the time lag for the TF to exert regulatory effects on its target genes. We also identified 178 novel cell cycle-regulated genes, among which 59 have unknown functions, but they may now be annotated as cell cycle-regulated genes. Most of our predictions are supported by previous experimental or computational studies. Furthermore, a high confidence TF-gene regulatory matrix is derived as a byproduct of our method. Each TF-gene regulatory relationship in this matrix is supported by at least three data sources: gene expression, TFBS, and ChIP-chip or/and mutant data. We show that our method performs better than four existing methods for identifying yeast cell cycle TFs. Finally, an application of our method to different cell cycle gene expression datasets suggests that our method is robust. Conclusion Our method is effective for identifying yeast cell cycle TFs and cell cycle-regulated genes. Many of our predictions are validated by the literature. Our study shows that integrating multiple data sources is a powerful approach to studying complex biological systems.

  9. Computational analysis of mammalian cell division gated by a circadian clock: quantized cell cycles and cell size control.

    Science.gov (United States)

    Zámborszky, Judit; Hong, Christian I; Csikász Nagy, Attila

    2007-12-01

    Cell cycle and circadian rhythms are conserved from cyanobacteria to humans with robust cyclic features. Recently, molecular links between these two cyclic processes have been discovered. Core clock transcription factors, Bmal1 and Clock (Clk), directly regulate Wee1 kinase, which inhibits entry into the mitosis. We investigate the effect of this connection on the timing of mammalian cell cycle processes with computational modeling tools. We connect a minimal model of circadian rhythms, which consists of transcription-translation feedback loops, with a modified mammalian cell cycle model from Novak and Tyson (2004). As we vary the mass doubling time (MDT) of the cell cycle, stochastic simulations reveal quantized cell cycles when the activity of Wee1 is influenced by clock components. The quantized cell cycles disappear in the absence of coupling or when the strength of this link is reduced. More intriguingly, our simulations indicate that the circadian clock triggers critical size control in the mammalian cell cycle. A periodic brake on the cell cycle progress via Wee1 enforces size control when the MDT is quite different from the circadian period. No size control is observed in the absence of coupling. The issue of size control in the mammalian system is debatable, whereas it is well established in yeast. It is possible that the size control is more readily observed in cell lines that contain circadian rhythms, since not all cell types have a circadian clock. This would be analogous to an ultradian clock intertwined with quantized cell cycles (and possibly cell size control) in yeast. We present the first coupled model between the mammalian cell cycle and circadian rhythms that reveals quantized cell cycles and cell size control influenced by the clock.

  10. Human Cpr (Cell Cycle Progression Restoration) Genes Impart a Far(-) Phenotype on Yeast Cells

    OpenAIRE

    Edwards, M. C.; Liegeois, N.; Horecka, J.; DePinho, R A; Sprague-Jr., G. F.; Tyers, M; Elledge, S J

    1997-01-01

    Regulated cell cycle progression depends on the proper integration of growth control pathways with the basic cell cycle machinery. While many of the central molecules such as cyclins, CDKs, and CKIs are known, and many of the kinases and phosphatases that modify the CDKs have been identified, little is known about the additional layers of regulation that impinge upon these molecules. To identify new regulators of cell proliferation, we have selected for human and yeast cDNAs that when overexp...

  11. Mechanistic insights into aging, cell cycle progression, and stress response

    Directory of Open Access Journals (Sweden)

    Troy Anthony Alan Harkness

    2012-06-01

    Full Text Available The longevity of an organism depends on the health of its cells. Throughout life cells are exposed to numerous intrinsic and extrinsic stresses, such as free radicals, generated through mitochondrial electron transport, and ultraviolet irradiation. The cell has evolved numerous mechanisms to scavenge free radicals and repair damage induced by these insults. One mechanism employed by the yeast Saccharomyces cerevisiae to combat stress utilizes the Anaphase Promoting Complex (APC, an essential multi-subunit ubiquitin-protein ligase structurally and functionally conserved from yeast to humans that controls progression through mitosis and G1. We have observed that yeast cells expressing compromised APC subunits are sensitive to multiple stresses and have shorter replicative and chronological lifespans. In a pathway that runs parallel to that regulated by the APC, members of the Forkhead box (Fox transcription factor family also regulate stress responses. The yeast Fox orthologues Fkh1 and Fkh2 appear to drive the transcription of stress response factors and slow early G1 progression, while the APC seems to regulate chromatin structure, chromosome segregation, and resetting of the transcriptome in early G1. In contrast, under non-stress conditions, the Fkhs play a complex role in cell cycle progression, partially through activation of the APC. Direct and indirect interactions between the APC and the yeast Fkhs appear to be pivotal for lifespan determination. Here we explore the potential for these interactions to be evolutionarily conserved as a mechanism to balance cell cycle regulation with stress responses.

  12. Local homogeneity of cell cycle length in developing mouse cortex

    Science.gov (United States)

    Cai, L.; Hayes, N. L.; Nowakowski, R. S.

    1997-01-01

    We have measured the amount of variation in the length of the cell cycle for cells in the pseudostratified ventricular epithelium (PVE) of the developing cortex of mice on embryonic day 14. Our measurements were made in three cortical regions (i.e., the neocortex, archicortex, and periarchicortex) using three different methods: the cumulative labeling method (CLM), the percent labeled mitoses (PLM) method, and a comparison of the time needed for the PLM to ascend from 0 to 100% with the time needed for the PLM to descend from 100 to 0%. These 3 different techniques provide different perspectives on the cytokinetic parameters. Theoretically, CLM gives an estimate for a maximum value of the total length of the cell cycle (TC), whereas PLM gives an estimate of a minimum value of TC. The difference between these two estimates indicates that the range for TC is +/-1% of the mean TC for periarchicortex, +/-7% for neocortex, and +/-8% for archicortex. This was confirmed by a lengthening of the PLM descent time in comparison with its ascent time. The sharpness of the transitions and the flatness of the plateau of the PLM curves indicate that 99% of the proliferating cells are within this narrow estimated range for TC; hence, only approximately 1% deviate outside of a relatively restricted range from the average TC of the population. In the context of the possible existence within the cortical PVE of two populations with markedly dissimilar cell cycle kinetics from the mean, one such population must comprise approximately 99% of the total population, and the other, if it exists, is only approximately 1% of the total. This seems to be true for all three cortical regions. The narrow range of TC indicates a homogeneity in the cell cycle length for proliferating cells in three different cortical regions, despite the fact that progenitor cells of different lineages may be present. It further predicts the existence of almost synchronous interkinetic nuclear movements of the

  13. Differential regulation of survivin by p53 contributes to cell cycle dependent apoptosis

    Institute of Scientific and Technical Information of China (English)

    Yan JIN; Yong WEI; Lei XIONG; Ying YANG; Jia Rui WU

    2005-01-01

    Recent studies indicate that cell-cycle checkpoints are tightly correlated with the regulation of apoptosis, in which p53 plays an important role. Our present works show that the expression of E6/E7 oncogenes of human papillomavirus in HeLa cells is inhibited in the presence of anti-tumor reagent tripchlorolide (TC), which results in the up-regulation of p53 in HeLa cells. Interestingly, under the same TC-treatment, the cells at the early S-phase are more susceptible to apoptosis than those at the middle S-phase although p53 protein is stabilized to the same level in both situations.Significant difference is exhibited between the two specified expression profiles. Further analysis demonstrates that anti-apoptotic gene survivin is up-regulated by p53 in the TC-treated middle-S cells, whereas it is down-regulated by p53 in the TC-treated early-S cells. Taken together, the present study indicates that the differential p53-regulated expression of survivin at different stages of the cell cycle results in different cellular outputs under the same apoptosis-inducer.

  14. Part II-mechanism of adaptation: A549 cells adapt to high concentration of nitric oxide through bypass of cell cycle checkpoints.

    Science.gov (United States)

    Aqil, Madeeha; Deliu, Zane; Elseth, Kim M; Shen, Grace; Xue, Jiaping; Radosevich, James A

    2014-03-01

    Previous work has shown enhanced survival capacity in high nitric oxide (HNO)-adapted tumor cells. In Part I of this series of manuscripts, we have shown that A549-HNO cells demonstrate an improved growth profile under UV and X-ray radiation treatment. These cells exhibit increased expression of proteins involved in DNA damage recognition and repair pathway, both the non-homologous end joining pathway and homologous recombination. These include Ku80, DNA-PK, XLF ligase and MRN complex proteins. Further, the A549-HNO cells show high levels of ATM, ATR, Chk1 and Chk2, and phospho-p53. Activation of these molecules may lead to cell cycle arrest and apoptosis due to DNA damage. This is observed in parent A549 cells in response to NO donor treatment; however, the A549-HNO cells proliferate and inhibit apoptosis. Cell cycle analysis showed slowed progression through S phase which will allow time for DNA repair. Thus, to better understand the increased growth rate in A549-HNO when compared to the parent cell line A549, we studied molecular mechanisms involved in cell cycle regulation in A549-HNO cells. During the initial time period of NO donor treatment, we observe high levels of cyclin/Cdk complexes involved in regulating various stages of the cell cycle. This would lead to bypass of G1-S and G2-M checkpoints. The HNO cells also show much higher expression of Cdc25A. Cdc25A activates Cdk molecules involved in different phases of the cell cycle. In addition, there is enhanced phosphorylation of the Rb protein in HNO cells. This leads to inactivation of Rb/E2F checkpoint regulating G1-S transition. This may lead to faster progression in S phase. Thus, all of these perturbations in HNO cells lead to accelerated cell cycle progression and a higher growth rate. We also assessed expression of cell cycle inhibitors in HNO cells. Interestingly, the HNO cells show a significant decline in p21CIP1 at initial time points, but with prolonged exposure, the levels were much higher

  15. The Cell Cycle Timing of Human Papillomavirus DNA Replication.

    Science.gov (United States)

    Reinson, Tormi; Henno, Liisi; Toots, Mart; Ustav, Mart; Ustav, Mart

    2015-01-01

    Viruses manipulate the cell cycle of the host cell to optimize conditions for more efficient viral genome replication. One strategy utilized by DNA viruses is to replicate their genomes non-concurrently with the host genome; in this case, the viral genome is amplified outside S phase. This phenomenon has also been described for human papillomavirus (HPV) vegetative genome replication, which occurs in G2-arrested cells; however, the precise timing of viral DNA replication during initial and stable replication phases has not been studied. We developed a new method to quantitate newly synthesized DNA levels and used this method in combination with cell cycle synchronization to show that viral DNA replication is initiated during S phase and is extended to G2 during initial amplification but follows the replication pattern of cellular DNA during S phase in the stable maintenance phase. E1 and E2 protein overexpression changes the replication time from S only to both the S and G2 phases in cells that stably maintain viral episomes. These data demonstrate that the active synthesis and replication of the HPV genome are extended into the G2 phase to amplify its copy number and the duration of HPV genome replication is controlled by the level of the viral replication proteins E1 and E2. Using the G2 phase for genome amplification may be an important adaptation that allows exploitation of changing cellular conditions during cell cycle progression. We also describe a new method to quantify newly synthesized viral DNA levels and discuss its benefits for HPV research.

  16. Cell cycle arrest induced by MPPa-PDT in MDA-MB-231 cells

    Science.gov (United States)

    Liang, Liming; Bi, Wenxiang; Tian, Yuanyuan

    2016-05-01

    Photodynamic therapy (PDT) is a medical treatment using a photosensitizing agent and light source to treat cancers. Pyropheophorbidea methyl ester (MPPa), a derivative of chlorophyll, is a novel potent photosensitizer. To learn more about this photosensitizer, we examined the cell cycle arrest in MDA-MB-231. Cell cycle and apoptosis were measured by flow cytometer. Checkpoints of the cell cycle were measured by western blot. In this study, we found that the expression of Cyclin D1 was obviously decreased, while the expression of Chk2 and P21 was increased after PDT treatment. This study showed that MPPa-PDT affected the checkpoints of the cell cycle and led the cells to apoptosis.

  17. Synchronization of Green Algae by Light and Dark Regimes for Cell Cycle and Cell Division Studies.

    Science.gov (United States)

    Hlavová, Monika; Vítová, Milada; Bišová, Kateřina

    2016-01-01

    A synchronous population of cells is one of the prerequisites for studying cell cycle processes such as DNA replication, nuclear and cellular division. Green algae dividing by multiple fission represent a unique single cell system enabling the preparation of highly synchronous cultures by application of a light-dark regime similar to what they experience in nature. This chapter provides detailed protocols for synchronization of different algal species by alternating light-dark cycles; all critical points are discussed extensively. Moreover, detailed information on basic analysis of cell cycle progression in such cultures is presented, including analyses of nuclear, cellular, and chloroplast divisions. Modifications of basic protocols that enable changes in cell cycle progression are also suggested so that nuclear or chloroplast divisions can be followed separately.

  18. Cell-cycle research with synchronous cultures: an evaluation

    Science.gov (United States)

    Helmstetter, C. E.; Thornton, M.; Grover, N. B.

    2001-01-01

    The baby-machine system, which produces new-born Escherichia coli cells from cultures immobilized on a membrane, was developed many years ago in an attempt to attain optimal synchrony with minimal disturbance of steady-state growth. In the present article, we put forward a model to describe the behaviour of cells produced by this method, and provide quantitative evaluation of the parameters involved, at each of four different growth rates. Considering the high level of selection achievable with this technique and the natural dispersion in interdivision times, we believe that the output of the baby machine is probably close to optimal in terms of both quality and persistence of synchrony. We show that considerable information on events in the cell cycle can be obtained from populations with age distributions very much broader than those achieved with the baby machine and differing only modestly from steady state. The data presented here, together with the long and fruitful history of findings employing the baby-machine technique, suggest that minimisation of stress on cells is the single most important factor for successful cell-cycle analysis.

  19. ICSI choreography: fate of sperm structures after monospermic rhesus ICSI and first cell cycle implications.

    Science.gov (United States)

    Ramalho-Santos, J; Sutovsky, P; Simerly, C; Oko, R; Wessel, G M; Hewitson, L; Schatten, G

    2000-12-01

    We have dissected the initial stages of fertilization by intracytoplasmic sperm injection of single spermatozoa into prime oocytes from fertile rhesus monkeys (Macaca mulatta). DNA decondensation was delayed at the apical portion of the sperm head. It is possible that this asynchronous male DNA decondensation could be related to the persistence of the sperm acrosome and perinuclear theca after injection. However, incomplete male pronuclear formation did not prevent sperm aster formation, microtubule nucleation and pronuclear apposition. In contrast, DNA synthesis was delayed in both pronuclei until the sperm chromatin fully decondensed, indicating that male pronuclear formation constitutes an important checkpoint during the first embryonic cell cycle.

  20. The localization of Toll-like receptor 2 (TLR2) in the endometrium and the cervix of dogs at different stages of the oestrous cycle and with pyometra.

    Science.gov (United States)

    Chotimanukul, S; Sirivaidyapong, S

    2012-12-01

    The aim of this study was to localize and evaluate the role of Toll-like receptor 2 (TLR2) in the endometrium and cervix of bitches at different stages of the oestrous cycle and in bitches with pyometra. Sixty-seven nulliparous dogs, ranging in age from 1 to 13 years, were allocated amongst five groups (pro-oestrus; n = 7, oestrus; n = 10, dioestrus; n = 16, anoestrus; n = 11, pyometra; n = 23). Blood samples were collected for the measurement of progesterone concentration. The mean progesterone concentration was analysed as a parameter for validating the stage of the oestrous cycle in bitches. Tissues collected from uterine horn and cervix were fixed in 4% paraformaldehyde for immunohistochemical examination of TLR2. The expression of TLR2 was assessed semi-quantitatively. No pathological changes were found in the uterine samples of healthy dogs. In bitches with pyometra, the glandular epithelium expressed TLR2 more intensely than the surface epithelium. The expression of TLR2 in the glandular epithelium was also significantly higher in healthy dogs at oestrus, dioestrus and dogs with pyometra compared with anoestrous dogs (p < 0.01). The expression of TLR2 in the stroma was not observed in the group of healthy dogs at all stages. The surface epithelium of cervix in dogs with pyometra expressed TLR2 significantly more intensely than did the stoma, whereas the expression of TLR2 during oestrus and dioestrus was absent in the stroma of cervix. This study provides the first report of immunohistochemical localization of TLR2 in the canine reproductive tract. In the present study, TLR2 was expressed in endometrial epithelium but was absent in the endometrial stroma of healthy dogs at all oestrous cycle stages. These findings suggest differential expression of TLR in endometrial cells. On the other hand, the lack of TLR2 in the stroma of healthy uteri of dogs may predispose to infection from the invading pathogens once the epithelial cells have been destroyed by the

  1. Functional dissection of Caenorhabditis elegans CLK-2/TEL2 cell cycle defects during embryogenesis and germline development.

    Directory of Open Access Journals (Sweden)

    Sandra C Moser

    2009-04-01

    Full Text Available CLK-2/TEL2 is essential for viability from yeasts to vertebrates, but its essential functions remain ill defined. CLK-2/TEL2 was initially implicated in telomere length regulation in budding yeast, but work in Caenorhabditis elegans has uncovered a function in DNA damage response signalling. Subsequently, DNA damage signalling defects associated with CLK-2/TEL2 have been confirmed in yeast and human cells. The CLK-2/TEL2 interaction with the ATM and ATR DNA damage sensor kinases and its requirement for their stability led to the proposal that CLK-2/TEL2 mutants might phenocopy ATM and/or ATR depletion. We use C. elegans to dissect developmental and cell cycle related roles of CLK-2. Temperature sensitive (ts clk-2 mutants accumulate genomic instability and show a delay of embryonic cell cycle timing. This delay partially depends on the worm p53 homolog CEP-1 and is rescued by co-depletion of the DNA replication checkpoint proteins ATL-1 (C. elegans ATR and CHK-1. In addition, clk-2 ts mutants show a spindle orientation defect in the eight cell stages that lead to major cell fate transitions. clk-2 deletion worms progress through embryogenesis and larval development by maternal rescue but become sterile and halt germ cell cycle progression. Unlike ATL-1 depleted germ cells, clk-2-null germ cells do not accumulate DNA double-strand breaks. Rather, clk-2 mutant germ cells arrest with duplicated centrosomes but without mitotic spindles in an early prophase like stage. This germ cell cycle arrest does not depend on cep-1, the DNA replication, or the spindle checkpoint. Our analysis shows that CLK-2 depletion does not phenocopy PIKK kinase depletion. Rather, we implicate CLK-2 in multiple developmental and cell cycle related processes and show that CLK-2 and ATR have antagonising functions during early C. elegans embryonic development.

  2. Effects of mimosine on Wolbachia in mosquito cells: cell cycle suppression reduces bacterial abundance.

    Science.gov (United States)

    Fallon, Ann M

    2015-10-01

    The plant allelochemical L-mimosine (β-[N-(3-hydroxy-4-pyridone)]-α-aminopropionic acid; leucenol) resembles the nonessential amino acid, tyrosine. Because the obligate intracellular alphaproteobacterium, Wolbachia pipientis, metabolizes amino acids derived from host cells, the effects of mimosine on infected and uninfected mosquito cells were investigated. The EC50 for mimosine was 6-7 μM with Aedes albopictus C7-10 and C/wStr cell lines, and was not influenced by infection status. Mosquito cells responded to concentrations of mimosine substantially lower than those used to synchronize the mammalian cell cycle; at concentrations of 30-35 μM, mimosine reversibly arrested the mosquito cell cycle at the G1/S boundary and inhibited growth of Wolbachia strain wStr. Although lower concentrations of mimosine slightly increased wStr abundance, concentrations that suppressed the cell cycle reduced Wolbachia levels.

  3. TRICHOSTATIN A INHIBITS PROLIFERATION, INDUCES APOPTOSIS AND CELL CYCLE ARREST IN HELA CELLS

    Institute of Scientific and Technical Information of China (English)

    XU Zhou-min; WANG Yi-qun; MEI Qi; CHEN Jian; DU Jia; WEI Yan; XU Ying-chun

    2006-01-01

    Objective: The histone deacetylase inhibitors (HDACIS) have been shown to inhibit cancer cell proliferation, stimulate apoptosis, an induce cell cycle arrest. Our purpose was to investigate the antiproliferative effects of a HDACI, trichostatin A (TSA), against human cervical cancer cells (HeLa). Methods: HeLa cells were treated in vitro with various concentrations of TSA. The inhibitory effect of TSA on the growth of HeLa cells was measured by MTT assay. To detect the characteristic of apoptosis chromatin condensation, HeLa cells were stained with Hoechst 33258 in the presence of TSA. Induction of cell cycle arrest was studied by flow cytometry. Changes in gene expression of p53, p21Waf1 and p27Kip1 were studied by semiquantitative RT-PCR. Results: TSA inhibited cell growth in a time- and dose-dependent manner. Hoechst 33258 staining assay showed that TSA induced apoptosis. Cell cycle analysis indicated that treatment with TSA decreased the proportion of cells in S phase and increased the proportion of cells in G0/G1 and/or G2/M phases of the cell cycle. This was concomitant with overexpression of genes related to malignant phenotype, including an increase in p53, p21Waf1 and p27Kip1. Conclusion: These results suggest that TSA is effective in inhibiting growth of HeLa cells in vitro. The findings raise the possibility that TSA may prove particularly effective in treatment of cervical cancers.

  4. Effects of Trichostatin A on HDAC8 Expression, Proliferation and Cell Cycle of Molt-4 Cells

    Institute of Scientific and Technical Information of China (English)

    HE Jing; LIU Hongli; CHEN Yan

    2006-01-01

    The effects of Trichostatin A (TSA) on histone deacetylase 8 (HDAC8) expression, proliferation and cell cycle arrest in T-lymphoblastic leukemia cell line Molt-4 cells in vitro were investigated. The effect of TSA on the growth of Molt-4 cells was studied by MTT assay. Flow cytometry was used to examine the cell cycle. The expression of HDAC8 was detected by using immunocytochemistry and Western blot. The results showed that proliferation of Molt-4 cells was inhibited in TSA-treated group in a time- and dose-dependent manner. The IC50 of TSA exposures for 24 h and 36 h were 254.3236 and 199.257 μg/L respectively. The cell cycle analysis revealed that Molt-4 was mostly in G0/G1 phase, and after treatment with TSA from 50 to 400 μg/L for 24 h, the percents of G0/G1 cells were decreased and cells were arrested in G2/M phase. Treatment of TSA for 24 h could significantly inhibit the expression of HDAC8 protein in Molt-4 cells (P<0.01). It was concluded that TSA could decrease the expression of HDAC8 in Molt-4 cells, which contributed to the inhibition of proliferation and induction of cell cycle arrest in Molt-4 cells.

  5. Linalool Induces Cell Cycle Arrest and Apoptosis in Leukemia Cells and Cervical Cancer Cells through CDKIs.

    Science.gov (United States)

    Chang, Mei-Yin; Shieh, Den-En; Chen, Chung-Chi; Yeh, Ching-Sheng; Dong, Huei-Ping

    2015-01-01

    Plantaginaceae, a popular traditional Chinese medicine, has long been used for treating various diseases from common cold to cancer. Linalool is one of the biologically active compounds that can be isolated from Plantaginaceae. Most of the commonly used cytotoxic anticancer drugs have been shown to induce apoptosis in susceptible tumor cells. However, the signaling pathway for apoptosis remains undefined. In this study, the cytotoxic effect of linalool on human cancer cell lines was investigated. Water-soluble tetrazolium salts (WST-1) based colorimetric cellular cytotoxicity assay, was used to test the cytotoxic ability of linalool against U937 and HeLa cells, and flow cytometry (FCM) and genechip analysis were used to investigate the possible mechanism of apoptosis. These results demonstrated that linalool exhibited a good cytotoxic effect on U937 and HeLa cells, with the IC50 value of 2.59 and 11.02 μM, respectively, compared with 5-FU with values of 4.86 and 12.31 μM, respectively. After treating U937 cells with linalool for 6 h, we found an increased sub-G1 peak and a dose-dependent phenomenon, whereby these cells were arrested at the G0/G1 phase. Furthermore, by using genechip analysis, we observed that linalool can promote p53, p21, p27, p16, and p18 gene expression. Therefore, this study verified that linalool can arrest the cell cycle of U937 cells at the G0/G1 phase and can arrest the cell cycle of HeLa cells at the G2/M phase. Its mechanism facilitates the expression of the cyclin-dependent kinases inhibitors (CDKIs) p53, p21, p27, p16, and p18, as well as the non-expression of cyclin-dependent kinases (CDKs) activity.

  6. Linalool Induces Cell Cycle Arrest and Apoptosis in Leukemia Cells and Cervical Cancer Cells through CDKIs

    Directory of Open Access Journals (Sweden)

    Mei-Yin Chang

    2015-11-01

    Full Text Available Plantaginaceae, a popular traditional Chinese medicine, has long been used for treating various diseases from common cold to cancer. Linalool is one of the biologically active compounds that can be isolated from Plantaginaceae. Most of the commonly used cytotoxic anticancer drugs have been shown to induce apoptosis in susceptible tumor cells. However, the signaling pathway for apoptosis remains undefined. In this study, the cytotoxic effect of linalool on human cancer cell lines was investigated. Water-soluble tetrazolium salts (WST-1 based colorimetric cellular cytotoxicity assay, was used to test the cytotoxic ability of linalool against U937 and HeLa cells, and flow cytometry (FCM and genechip analysis were used to investigate the possible mechanism of apoptosis. These results demonstrated that linalool exhibited a good cytotoxic effect on U937 and HeLa cells, with the IC50 value of 2.59 and 11.02 μM, respectively, compared with 5-FU with values of 4.86 and 12.31 μM, respectively. After treating U937 cells with linalool for 6 h, we found an increased sub-G1 peak and a dose-dependent phenomenon, whereby these cells were arrested at the G0/G1 phase. Furthermore, by using genechip analysis, we observed that linalool can promote p53, p21, p27, p16, and p18 gene expression. Therefore, this study verified that linalool can arrest the cell cycle of U937 cells at the G0/G1 phase and can arrest the cell cycle of HeLa cells at the G2/M phase. Its mechanism facilitates the expression of the cyclin-dependent kinases inhibitors (CDKIs p53, p21, p27, p16, and p18, as well as the non-expression of cyclin-dependent kinases (CDKs activity.

  7. CDK inhibitors, p21{sup Cip1} and p27{sup Kip1}, participate in cell cycle exit of mammalian cardiomyocytes

    Energy Technology Data Exchange (ETDEWEB)

    Tane, Shoji; Ikenishi, Aiko; Okayama, Hitomi; Iwamoto, Noriko [School of Life Sciences, Faculty of Medicine, Tottori University, Yonago 683-8503 (Japan); Nakayama, Keiichi I. [Medical Institute of Bioregulation, Kyushu University, Fukuoka 812-8582 (Japan); Takeuchi, Takashi, E-mail: takeuchi@med.tottori-u.ac.jp [School of Life Sciences, Faculty of Medicine, Tottori University, Yonago 683-8503 (Japan)

    2014-01-17

    Highlights: •Expression of p21 and p27 in the hearts showed a peak during postnatal stages. •p21 and p27 bound to cyclin E, cyclin A and CDK2 in the hearts at postnatal stages. •Cardiomyocytes in both KO mice showed failure in the cell cycle exit at G1-phase. •These data show the first apparent phenotypes in the hearts of Cip/Kip KO mice. -- Abstract: Mammalian cardiomyocytes actively proliferate during embryonic stages, following which cardiomyocytes exit their cell cycle after birth. The irreversible cell cycle exit inhibits cardiac regeneration by the proliferation of pre-existing cardiomyocytes. Exactly how the cell cycle exit occurs remains largely unknown. Previously, we showed that cyclin E- and cyclin A-CDK activities are inhibited before the CDKs levels decrease in postnatal stages. This result suggests that factors such as CDK inhibitors (CKIs) inhibit CDK activities, and contribute to the cell cycle exit. In the present study, we focused on a Cip/Kip family, which can inhibit cyclin E- and cyclin A-CDK activities. Expression of p21{sup Cip1} and p27{sup Kip1} but not p57{sup Kip2} showed a peak around postnatal day 5, when cyclin E- and cyclin A-CDK activities start to decrease. p21{sup Cip1} and p27{sup Kip1} bound to cyclin E, cyclin A and CDK2 at postnatal stages. Cell cycle distribution patterns of postnatal cardiomyocytes in p21{sup Cip1} and p27{sup Kip1} knockout mice showed failure in the cell cycle exit at G1-phase, and endoreplication. These results indicate that p21{sup Cip1} and p27{sup Kip} play important roles in the cell cycle exit of postnatal cardiomyocytes.

  8. POST-OPERATIVE STAGING AND SURVIVAL BASED ON THE REVISED TNM STAGING SYSTEM FOR NON-SMALL CELL LUNG CANCER

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To study the factors affecting post-operative staging and survival in non-small cell lung cancer (NSCLC) patients based on the revised TNM staging system adopted by the UICC in 1977. Methods: Data were collected from 1757 consecutively operated NSCLC patients, including those receiving complete tumor excision, tumor debulking and exploratory thoractomy from April 1969 through Dec. 1993. the end point of follow-up was Nov. 30, 1998. Cumulative survival and its influencing factors were analyzed by Kaplan-Meier and Cox model of SPSS software. Results: In this series, 30 patients (1.7%) were lost from follow-up. The 5-year cumulative survival was 88.0% for patients in stage I A, and 53.9% in stage IB, 33.5% in stage II, 14.7% in stage IIIA, 5.5% in stage IIIB and 7.0% in stage IV. The overall 5-year survival rate was 28.2%. The 5-year survivals were 39.8%, 14.4% and 4.2% in patients treated with completely tumor resection, tumor debulking and explorative thoractomy, respectively. The 10-year survival rate was 31.4%, 9.5% and 0, respectively. Factors affecting long-term cumulative survival, in the order of decreasing significance, were the type of operation, lymph node status, staging, size and pathological type of the primary tumor. Conclusion: the revised staging system for NSCLC is superior to that used since 1986 as far as the end results of treatment in patients in different stage and the staging specificity are concerned. The T3N1M0 classification and the definition of M1 need to be further studied.

  9. Characterization and Evolution of the Cell Cycle-Associated Mob Domain-Containing Proteins in Eukaryotes

    Directory of Open Access Journals (Sweden)

    Nicola Vitulo

    2007-01-01

    Full Text Available The MOB family includes a group of cell cycle-associated proteins highly conserved throughout eukaryotes, whose founding members are implicated in mitotic exit and co-ordination of cell cycle progression with cell polarity and morphogenesis. Here we report the characterization and evolution of the MOB domain-containing proteins as inferred from the 43 eukaryotic genomes so far sequenced. We show that genes for Mob-like proteins are present in at least 41 of these genomes, confi rming the universal distribution of this protein family and suggesting its prominent biological function. The phylogenetic analysis reveals fi ve distinct MOB domain classes, showing a progressive expansion of this family from unicellular to multicellular organisms, reaching the highest number in mammals. Plant Mob genes appear to have evolved from a single ancestor, most likely after the loss of one or more genes during the early stage of Viridiplantae evolutionary history. Three of the Mob classes are widespread among most of the analyzed organisms. The possible biological and molecular function of Mob proteins and their role in conserved signaling pathways related to cell proliferation, cell death and cell polarity are also presented and critically discussed.

  10. A conserved DNA damage response pathway responsible for coupling the cell division cycle to the circadian and metabolic cycles.

    Science.gov (United States)

    Chen, Zheng; McKnight, Steven L

    2007-12-01

    The circadian clock drives endogenous oscillations of cellular and physiological processes with a periodicity of approximately 24 h. Progression of the cell division cycle (CDC) has been found to be coupled to the circadian clock, and it has been postulated that gating of the CDC by the circadian cycle may have evolved to protect DNA from the mutagenic effects of ultraviolet light. When grown under nutrient-limiting conditions in a chemostat, prototrophic strains of budding yeast, Saccharomyces cerevisiae, adopt a robust metabolic cycle of ultradian dimensions that temporally compartmentalizes essential cellular events. The CDC is gated by this yeast metabolic cycle (YMC), with DNA replication strictly segregated away from the oxidative phase when cells are actively respiring. Mutants impaired in such gating allow DNA replication to take place during the respiratory phase of the YMC and have been found to suffer significantly elevated rates of spontaneous mutation. Analogous to the circadian cycle, the YMC also employs the conserved DNA checkpoint kinase Rad53/Chk2 to facilitate coupling with the CDC. These studies highlight an evolutionarily conserved mechanism that seems to confine cell division to particular temporal windows to prevent DNA damage. We hypothesize that DNA damage itself might constitute a "zeitgeber", or time giver, for both the circadian cycle and the metabolic cycle. We discuss these findings in the context of a unifying theme underlying the circadian and metabolic cycles, and explore the relevance of cell cycle gating to human diseases including cancer.

  11. Low cycle fatigue analysis of a last stage steam turbine blade

    Directory of Open Access Journals (Sweden)

    Měšťánek P.

    2008-11-01

    Full Text Available The present paper deals with the low cycle fatigue analysis of the low pressure (LP steam turbine blade. The blade is cyclically loaded by the centrifugal force because of the repeated startups of the turbine. The goal of the research is to develop a technique to assess fatigue life of the blade and to determine the number of startups to the crack initiation. Two approaches were employed. First approach is based on the elastic finite element analysis. Fictive 'elastic' results are recalculated using Neuber's rule and the equivalent energy method. Triaxial state of stress is reduced using von Mises theory. Strain amplitude is calculated employing the cyclic deformation curve. Second approach is based on elastic-plastic FE analysis. Strain amplitude is determined directly from the FE analysis by reducing the triaxial state of strain. Fatigue life was assessed using uniaxial damage parameters. Both approaches are compared and their applicability is discussed. Factors that can influence the fatigue life are introduced. Experimental low cycle fatigue testing is shortly described.

  12. Hubble Space Telescope solar cell module thermal cycle test

    Science.gov (United States)

    Douglas, Alexander; Edge, Ted; Willowby, Douglas; Gerlach, Lothar

    1992-01-01

    The Hubble Space Telescope (HST) solar array consists of two identical double roll-out wings designed after the Hughes flexible roll-up solar array (FRUSA) and was developed by the European Space Agency (ESA) to meet specified HST power output requirements at the end of 2 years, with a functional lifetime of 5 years. The requirement that the HST solar array remain functional both mechanically and electrically during its 5-year lifetime meant that the array must withstand 30,000 low Earth orbit (LEO) thermal cycles between approximately +100 and -100 C. In order to evaluate the ability of the array to meet this requirement, an accelerated thermal cycle test in vacuum was conducted at NASA's Marshall Space Flight Center (MSFC), using two 128-cell solar array modules which duplicated the flight HST solar array. Several other tests were performed on the modules. The thermal cycle test was interrupted after 2,577 cycles, and a 'cold-roll' test was performed on one of the modules in order to evaluate the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit. A posttest static shadow test was performed on one of the modules in order to analyze temperature gradients across the module. Finally, current in-flight electrical performance data from the actual HST flight solar array will be tested.

  13. Pitx2 expression promotes p21 expression and cell cycle exit in neural stem cells.

    Science.gov (United States)

    Heldring, Nina; Joseph, Bertrand; Hermanson, Ola; Kioussi, Chrissa

    2012-11-01

    Cortical development is a complex process that involves many events including proliferation, cell cycle exit and differentiation that need to be appropriately synchronized. Neural stem cells (NSCs) isolated from embryonic cortex are characterized by their ability of self-renewal under continued maintenance of multipotency. Cell cycle progression and arrest during development is regulated by numerous factors, including cyclins, cyclin dependent kinases and their inhibitors. In this study, we exogenously expressed the homeodomain transcription factor Pitx2, usually expressed in postmitotic progenitors and neurons of the embryonic cortex, in NSCs with low expression of endogenous Pitx2. We found that Pitx2 expression induced a rapid decrease in proliferation associated with an accumulation of NSCs in G1 phase. A search for potential cell cycle inhibitors responsible for such cell cycle exit of NSCs revealed that Pitx2 expression caused a rapid and dramatic (≉20-fold) increase in expression of the cell cycle inhibitor p21 (WAF1/Cip1). In addition, Pitx2 bound directly to the p21 promoter as assessed by chromatin immunoprecipitation (ChIP) in NSCs. Surprisingly, Pitx2 expression was not associated with an increase in differentiation markers, but instead the expression of nestin, associated with undifferentiated NSCs, was maintained. Our results suggest that Pitx2 promotes p21 expression and induces cell cycle exit in neural progenitors.

  14. Effect of Lithium on Cell Cycle Progression of Pig Airway Epithelial Cells

    Institute of Scientific and Technical Information of China (English)

    陈文书; 吴人亮; 王曦; 李媛; 郝天玲

    2004-01-01

    To investigate the effect of lithium on cell cycle progression of airway epithelial cells,primary pig tracheobronchial epithelial cells were incubated with lithium chloride (LiCl) at different concentrations (0, 5 mmol/L, and 10 mmol/L) and time (12 h, 16 h and 24 h). After the treatment, cells were counted, cell cycle profile was measured by BrdU labeling and flow cytometry, and expression of cyclin D1 and cyclin B1 were detected by Western blotting. The results showed that after 24h of 10mmol/L but not 5mmol/L LiCl treatment, proliferation of cells was slowed down as manifested by delayed confluence and cell number accumulation (P<0.05). Lithium did not change the percentage of cells in S phase (P>0.05), but 24 h incubation with 10 mmol/L LiCl induced a G2/M cell cycle arrest. Furthermore, 10mmol/L LiCl elevated cyclin D1 expression after 12h treatment, while expression of cyclin B1 increased more significantly after 24h incubation. These data demonstrate that lithium inhibits proliferation of pig airway epithelial cells by inhibiting cell cycle progression, and suggest that lithium-sensitive molecule(s) such as glycogen synthase kinase 3 may have a role in the regulation of growth of airway epithelial cells.

  15. Clinical variants, stages, and management of basal cell carcinoma

    Directory of Open Access Journals (Sweden)

    Lyubomir A Dourmishev

    2013-01-01

    Full Text Available Basal cell carcinoma (BCC is the most common paraneoplastic disease among human neoplasms. The tumor affects mainly photoexposed areas, most often in the head and seldom appears on genitalia and perigenital region. BCC progresses slowly and metastases are found in less than 0.5% of the cases; however, a considerable local destruction and mutilation could be observed when treatment is neglected or inadequate. Different variants as nodular, cystic, micronodular, superficial, pigment BCC are described in literature and the differential diagnosis in some cases could be difficult. The staging of BCC is made according to Tumor, Node, Metastasis (TNM classification and is essential for performing the adequate treatment. Numerous therapeutic methods established for treatment of BCC, having their advantages or disadvantages, do not absolutely dissolve the risk of relapses. The early diagnostics based on the good knowledge and timely organized and adequate treatment is a precondition for better prognosis. Despite the slow progress and numerous therapeutic methods, the basal cell carcinoma should not be underestimated.

  16. (p)ppGpp and the bacterial cell cycle

    Indian Academy of Sciences (India)

    Aanisa Nazir; Rajendran Harinarayanan

    2016-06-01

    Genes of the Rel/Spo homolog (RSH) superfamily synthesize and/or hydrolyse the modified nucleotides pppGpp/ppGpp (collectively referred to as (p)ppGpp) and are prevalent across diverse bacteria and in plant chloroplasts. Bacteria accumulate (p)ppGpp in response to nutrient deprivation (generically called the stringent response) and elicit appropriate adaptive responses mainly through the regulation of transcription. Although at different concentrations (p)ppGpp affect the expression of distinct set of genes, the two well-characterized responses are reduction in expression of the protein synthesis machinery and increase in the expression of genes coding for amino acid biosynthesis. In Escherichia coli, the cellular (p)ppGpp level inversely correlates with the growth rate and increasing its concentration decreases the steady state growth rate in a defined growth medium. Since change in growth rate must be accompanied by changes in cell cycle parameters set through the activities of the DNA replication and cell division apparatus, (p)ppGpp could coordinate protein synthesis (cell mass increase) with these processes. Here we review the role of (p)ppGpp in bacterial cell cycle regulation.

  17. (p)ppGpp and the bacterial cell cycle.

    Science.gov (United States)

    Nazir, Aanisa; Harinarayanan, Rajendran

    2016-06-01

    Genes of the Rel/Spo homolog (RSH) superfamily synthesize and/or hydrolyse the modified nucleotides pppGpp/ ppGpp (collectively referred to as (p)ppGpp) and are prevalent across diverse bacteria and in plant chloroplasts. Bacteria accumulate (p)ppGpp in response to nutrient deprivation (generically called the stringent response) and elicit appropriate adaptive responses mainly through the regulation of transcription. Although at different concentrations (p)ppGpp affect the expression of distinct set of genes, the two well-characterized responses are reduction in expression of the protein synthesis machinery and increase in the expression of genes coding for amino acid biosynthesis. In Escherichia coli, the cellular (p)ppGpp level inversely correlates with the growth rate and increasing its concentration decreases the steady state growth rate in a defined growth medium. Since change in growth rate must be accompanied by changes in cell cycle parameters set through the activities of the DNA replication and cell division apparatus, (p)ppGpp could coordinate protein synthesis (cell mass increase) with these processes. Here we review the role of (p)ppGpp in bacterial cell cycle regulation.

  18. Beneficial effects of an intradialytic cycling training program in patients with end-stage kidney disease.

    Science.gov (United States)

    Groussard, Carole; Rouchon-Isnard, Myriam; Coutard, Céline; Romain, Fanny; Malardé, Ludivine; Lemoine-Morel, Sophie; Martin, Brice; Pereira, Bruno; Boisseau, Nathalie

    2015-06-01

    In chronic kidney disease (CKD), oxidative stress (OS) plays a central role in the development of cardiovascular diseases. This pilot program aimed to determine whether an intradialytic aerobic cycling training protocol, by increasing physical fitness, could reduce OS and improve other CKD-related disorders such as altered body composition and lipid profile. Eighteen hemodialysis patients were randomly assigned to either an intradialytic training (cycling: 30 min, 55%-60% peak power, 3 days/week) group (EX; n = 8) or a control group (CON; n = 10) for 3 months. Body composition (from dual-energy X-ray absorptiometry), physical fitness (peak oxygen uptake and the 6-minute walk test (6MWT)), lipid profile (triglycerides (TG), total cholesterol, high-density lipoprotein, and low-density lipoprotein (LDL)), and pro/antioxidant status (15-F2α-isoprostanes (F2-IsoP) and oxidized LDL in plasma; superoxide dismutase, glutathione peroxidase, and reduced/oxidized glutathione in erythrocytes) were determined at baseline and 3 months later. The intradialytic training protocol did not modify body composition but had significant effects on physical fitness, lipid profile, and pro/antioxidant status. Indeed, at 3 months: (i) performance on the 6MWT was increased in EX (+23.4%, p < 0.001) but did not change in CON, (ii) plasma TG were reduced in EX (-23%, p < 0.03) but were not modified in CON, and (iii) plasma F2-IsoP concentrations were lower in EX than in CON (-35.7%, p = 0.02). In conclusion, our results show that 30 min of intradialytic training, 3 times per week for 3 months, are enough to exert beneficial effects on the most sensitive and reliable marker of lipid peroxidation (IsoP) while improving CKD-associated disorders (lipid profile and physical fitness). Intradialytic aerobic cycling training represents a useful and easy strategy to reduce CKD-associated disorders. These results need to be confirmed with a larger randomized study.

  19. Neferine, an alkaloid from lotus seed embryo, inhibits human lung cancer cell growth by MAPK activation and cell cycle arrest.

    Science.gov (United States)

    Poornima, Paramasivan; Weng, Ching Feng; Padma, Viswanadha Vijaya

    2014-01-01

    Neferine is the major bisbenzylisoquinoline alkaloid isolated from the seed embryo of a traditional medicinal plant Nelumbo nucifera (Lotus). Epidemiological studies have revealed the therapeutic potential of lotus seed embryo. Although several mechanisms have been proposed, a clear anticancer action mechanism of neferine on lung cancer cells is still not known. Lung cancer is the most common cause of cancer death in the world, and the patients with advanced stage of nonsmall lung cancer require adjunct chemotherapy after surgical resection for the eradication of cancer cells. In this study, the effects of neferine were evaluated and characterized in A549 cells. Neferine induced apoptosis in a dose-dependent manner with the hypergeneration of reactive oxygen species, activation of MAPKs, lipid peroxidation, depletion of cellular antioxidant pool, loss of mitochondrial membrane potential, and intracellular calcium accumulation. Furthermore, neferine treatment leads to the inhibition of nuclear factor kappaB and Bcl2, upregulation of Bax and Bad, release of cytochrome C, activation of caspase cascade, and DNA fragmentation. In addition, neferine could induce p53 and its effector protein p21 and downregulation of cell cycle regulatory protein cyclin D1 thereby inducing G1 cell cycle arrest. These results suggest a novel function of neferine as an apoptosis inducer in lung cancer cells.

  20. Inducible nucleotide excision repair (NER) of UV-induced cyclobutane pyrimidine dimers in the cell cycle of the budding yeast Saccharomyces cerevisiae: evidence that inducible NER is confined to the G1 phase of the mitotic cell cycle.

    Science.gov (United States)

    Scott, A D; Waters, R

    1997-03-18

    We previously reported on an inducible component of nucleotide excision repair in Saccharomyces cerevisiae that is controlled by the RAD16 gene. Here we describe a study of this event at the MAT alpha and HML alpha mating-type loci and on the transcribed (TS) and nontranscribed (NTS) strands of the RAD16 gene. Events were examined at various stages of the mitotic cycle in cells synchronised by centrifugal elutriation. Repair of cyclobutane pyrimidine dimers (CPDs) following a single UV dose does not vary significantly in different stages of the mitotic cell cycle. CPDs are removed more rapidly from the transcriptionally active MAT alpha locus than from the silent HML alpha locus, and the TS of RAD16 is repaired faster than the NTS in all stages of the cycle following a single UV irradiation. Enhanced excision of CPDs at MAT alpha and HML alpha can be induced only in the G1 and early S stages of the cell cycle. Here prior irradiation of cells with 25 J/m2 enhances the removal of CPDs following a second UV dose of 70 J/m2. The level of enhancement of repair does not differ significantly between MAT alpha and HML alpha in G1. Enhanced removal of CPDs is absent when cells receive the inducing dose in late S or G2/M. Repair of CPDs in both strands of RAD16 is similarly enhanced only if cells receive the initial irradiation in G1 and early S. The level of enhanced removal of CPDs is not significantly different in the TS and NTS of RAD16 either in asynchronous cells or in cells preirradiated in G1 and early S. It has been shown by others that UV-induced expression of RAD16 remains at high levels if cells are held in G1 by treatment with alpha factor. Therefore the increase in RAD16 transcript levels in G1 may be responsible for the ability to enhance NER solely in this stage of the cell cycle.

  1. The cell cycle, cell death, and cell morphology during retinoic acid-induced differentiation of embryonal carcinoma cells

    NARCIS (Netherlands)

    Mummery, C.L.; Brink, C.E. van den; Saag, P.T. van der; Laat, S.W. de

    1984-01-01

    Abstract Time-lapse films were made of PC13 embryonal carcinoma cells, synchronized by mitotic shake off, in the absence and presence of retinoic acid. Using a method based on the transition probability model, cell cycle parameters were determined during the first five generations following synchron

  2. Particle acceleration in sub-cycle optical cells

    CERN Document Server

    Terranova, F

    2014-01-01

    A single laser pulse with spot size smaller than half its wavelength ($w_0 < \\lambda/2$) can provide a net energy gain to ultra-relativistic particles. In this paper, we discuss the properties of an optical cell consisting of $N$ sub-cycle pulses that propagate in the direction perpendicular to the electron motion. We show that the energy gain produced by the cell is proportional to $N$ and it is sizable even for $\\mathcal{O}(1\\mathrm{ TW})$ pulses. The optical cell acts as a defocusing lens with chromatic aberration and can be treated as a linear component in conventional accelerators if the transverse size of the beam is of the order of $\\lambda$.

  3. Cell-cycle regulatory proteins in human wound healing

    DEFF Research Database (Denmark)

    Bartkova, Jirina; Grøn, Birgitte; Dabelsteen, Erik

    2003-01-01

    Proper healing of mucosal wounds requires careful orchestration of epithelial cell migration and proliferation. To elucidate the molecular basis of the lack of cellular proliferation in the migrating 'epithelial tongue' during the re-epithelialization of oral mucosal wounds, the expression of cell......-cycle regulators critical for G(1)-phase progression and S-phase entry was here analysed immunohistochemically. Compared to normal human mucosa, epithelia migrating to cover 2- or 3-day-old wounds made either in vivo or in an organotypic cell culture all showed loss of the proliferation marker Ki67 and cyclins D(1...... the abundance of most of the CKIs, including p27Kip1, p57Kip2, p15ink4b and p18ink4c, was relatively maintained in the migrating epithelial tongue. These data indicate that downmodulation of several G(1)/S-phase cyclins and a relative excess of CKIs may cooperate to ensure the quiescent state of migrating...

  4. Dissection of Cell Division Processes in the One Cell Stage Caenorhabditis elegans Embryo by Mutational Analysis

    Science.gov (United States)

    Gönczy, Pierre; Schnabel, Heinke; Kaletta, Titus; Amores, Ana Duran; Hyman, Tony; Schnabel, Ralf

    1999-01-01

    To identify novel components required for cell division processes in complex eukaryotes, we have undertaken an extensive mutational analysis in the one cell stage Caenorhabditis elegans embryo. The large size and optical properties of this cell permit observation of cell division processes with great detail in live specimens by simple differential interference contrast (DIC) microscopy. We have screened an extensive collection of maternal-effect embryonic lethal mutations on chromosome III with time-lapse DIC video microscopy. Using this assay, we have identified 48 mutations in 34 loci which are required for specific cell division processes in the one cell stage embryo. We show that mutations fall into distinct phenotypic classes which correspond, among others, to the processes of pronuclear migration, rotation of centrosomes and associated pronuclei, spindle assembly, chromosome segregation, anaphase spindle positioning, and cytokinesis. We have further analyzed pronuclear migration mutants by indirect immunofluorescence microscopy using antibodies against tubulin and ZYG-9, a centrosomal marker. This analysis revealed that two pronuclear migration loci are required for generating normal microtubule arrays and four for centrosome separation. All 34 loci have been mapped by deficiencies to distinct regions of chromosome III, thus paving the way for their rapid molecular characterization. Our work contributes to establishing the one cell stage C. elegans embryo as a powerful metazoan model system for dissecting cell division processes. PMID:10085292

  5. Identification of Echinococcus granulosus microRNAs and their expression in different life cycle stages and parasite genotypes.

    Science.gov (United States)

    Cucher, M; Prada, L; Mourglia-Ettlin, G; Dematteis, S; Camicia, F; Asurmendi, S; Rosenzvit, M

    2011-03-01

    The aetiological agent of cystic hydatid disease, the platyhelminth parasite Echinococcus granulosus, undergoes a series of metamorphic events during its complex life cycle. One of its developmental stages, the protoscolex, shows a remarkable degree of heterogeneous morphogenesis, being able to develop either into the vesicular or strobilar direction. Another level of complexity is added by the existence of genotypes or strains that differ in the range of intermediate hosts where they can develop and form fertile cysts. These features make E. granulosus an interesting model for developmental studies. Hence, we focused on the study of the regulation of gene expression by microRNAs (miRNAs), one of the key mechanisms that control development in metazoans and plants and which has not been analysed in E. granulosus yet. In this study, we cloned 38 distinct miRNAs, including four candidate new miRNAs that seem to be specific to Echinococcus spp. Thirty-four cloned sequences were orthologous to miRNAs already described in other organisms and were grouped in 16 metazoan miRNA families, some of them known for their role in the development of other organisms. The expression of some of the cloned miRNAs differs according to the parasite life cycle stage analysed, showing differential developmental expression. We did not detect differences in the expression of the analysed miRNAs between protoscoleces of two parasite genotypes. This work sets the scene for the study of gene regulation mediated by miRNAs in E. granulosus and provides a new approach to study the molecules involved in its developmental plasticity and intermediate host specificity. Understanding the developmental processes of E. granulosus may help to find new strategies for the control of cystic hydatid disease, caused by the metacestode stage of the parasite.

  6. Progesterone receptor membrane component-1 (PGRMC1) and PGRMC-2 interact to suppress entry into the cell cycle in spontaneously immortalized rat granulosa cells.

    Science.gov (United States)

    Peluso, John J; Griffin, Daniel; Liu, Xiufang; Horne, Meghan

    2014-11-01

    Progesterone receptor membrane component 1 (PGRMC1) and PGRMC2 are expressed in rat granulosa cells and spontaneously immortalized granulosa cells (SIGCs) but their biological roles are not well defined. The present studies demonstrate that depleting either Pgrmc1 or Pgrmc2 in SIGCs increases entry into the cell cycle but does not increase cell proliferation. Rather, PGRMC1 and/or PGRMC2-deplete cells accumulate in metaphase and undergo apoptosis. Because both PGRMC1 and PGRMC2 localize to the mitotic spindle, their absence likely accounts for cells arresting in metaphase. Moreover, pull-down assays, colocalization studies and in situ proximity ligation assays (PLA) indicate that PGRMC1 binds PGRMC2. Disrupting the PGRMC1:PGRMC2 complex through the use of siRNA or the cytoplasmic delivery of a PGRMC2 antibody increases entry into the cell cycle. Conversely, overexpressing either PGRMC1-GFP or GFP-PGRMC2 fusion protein inhibits entry into the cell cycle. Subsequent studies reveal that depleting PGRMC1 and/or PGRMC2 reduces the percentage of cells in G0 and increases the percentage of cells in G1. These observations indicate that in addition to their role at metaphase, PGRMC1 and PGRMC2 are involved in regulating entry into the G1 stage of the cell cycle. Interestingly, both PGRMC1 and PGRMC2 bind GTPase-activating protein-binding protein 2 (G3BP2) as demonstrated by pull-down assays, colocalization assays, and PLAs. G3bp2 siRNA treatment also promotes entry into the G1 stage. This implies that dynamic changes in the interaction among PGRMC1, PGRMC2, and G3BP2 play an important protein regulating the rate at which SIGCs enter into the cell cycle.

  7. Coupling between the circadian clock and cell cycle oscillators: implication for healthy cells and malignant growth

    Directory of Open Access Journals (Sweden)

    Celine eFeillet

    2015-05-01

    Full Text Available Uncontrolled cell proliferation is one of the key features leading to cancer. Seminal works in chronobiology have revealed that disruption of the circadian timing system in mice, either by surgical, genetic or environmental manipulation, increased tumor development. In humans, shift work is a risk factor for cancer. Based on these observations, the link between the circadian clock and cell cycle has become intuitive. But despite identification of molecular connections between the two processes, the influence of the clock on the dynamics of the cell cycle has never been formally observed. Recently, two studies combining single live cell imaging with computational methods have shed light on robust coupling between clock and cell cycle oscillators. We recapitulate here these novel findings and integrate them with earlier results in both healthy and cancerous cells. Moreover, we propose that the cell cycle may be synchronized or slowed down through coupling with the circadian clock, which results in reduced tumour growth. More than ever, systems biology has become instrumental to understand the dynamic interaction between the circadian clock and cell cycle, which is critical in cellular coordination and for diseases such as cancer.

  8. Coupling between the Circadian Clock and Cell Cycle Oscillators: Implication for Healthy Cells and Malignant Growth.

    Science.gov (United States)

    Feillet, Celine; van der Horst, Gijsbertus T J; Levi, Francis; Rand, David A; Delaunay, Franck

    2015-01-01

    Uncontrolled cell proliferation is one of the key features leading to cancer. Seminal works in chronobiology have revealed that disruption of the circadian timing system in mice, either by surgical, genetic, or environmental manipulation, increased tumor development. In humans, shift work is a risk factor for cancer. Based on these observations, the link between the circadian clock and cell cycle has become intuitive. But despite identification of molecular connections between the two processes, the influence of the clock on the dynamics of the cell cycle has never been formally observed. Recently, two studies combining single live cell imaging with computational methods have shed light on robust coupling between clock and cell cycle oscillators. We recapitulate here these novel findings and integrate them with earlier results in both healthy and cancerous cells. Moreover, we propose that the cell cycle may be synchronized or slowed down through coupling with the circadian clock, which results in reduced tumor growth. More than ever, systems biology has become instrumental to understand the dynamic interaction between the circadian clock and cell cycle, which is critical in cellular coordination and for diseases such as cancer.

  9. Impairment of cell cycle progression by sterigmatocystin in human pulmonary cells in vitro.

    Science.gov (United States)

    Huang, Shujuan; Wang, Juan; Xing, Lingxiao; Shen, Haitao; Yan, Xia; Wang, Junling; Zhang, Xianghong

    2014-04-01

    Sterigmatocystin (ST) is a carcinogenic mycotoxin that is commonly found in human food, animal feed and in the indoor environment. Although the correlation between ST exposure and lung cancer has been widely reported in many studies, the cytotoxicity of ST on human pulmonary cells is not yet fully understood. In the current study, we found that ST could induce DNA double-strand breaks in a human immortalized bronchial epithelial cell line (BEAS-2B cells) and a human lung cancer cell line (A549 cells). In addition, the effects of ST on cell cycle arrest were complex and dependent on the tested ST concentration and cell type. Low concentrations of ST arrested cells in the G2/M phase in BEAS-2B cells and in the S phase in A549 cells, while at high concentration both cells lines were arrested in S and G2/M phases. Furthermore, we observed that the modulation of cyclins and CDK expression showed concomitant changes with cell cycle arrest upon ST exposure in BEAS-2B and A549 cells. In conclusion, ST induced DNA damage and affected key proteins involved in cell cycle regulation to trigger genomic instability, which may be a potential mechanism underlying the developmental basis of lung carcinogenesis.

  10. Effects of cell cycle on the uptake of water soluble quantum dots by cells

    Science.gov (United States)

    Zheng, Shen; Chen, Ji-Yao; Wang, Jun-Yong; Zhou, Lu-Wei; Peng, Qian

    2011-12-01

    Quantum dots (QDs) with excellent optical properties have become powerful candidates for cell imaging. Although numerous reports have studied the uptake of QDs by cells, little information exists on the effects of cell cycle on the cellular QD uptake. In this report, the effects of cell cycle on the uptake of water soluble thiol-capped CdTe QDs by the human cervical carcinoma Hela cell line, human hepatocellular carcinoma QGY7701 cell line, and human embryonic kidney 293T cell line were studied by means of laser scanning confocal microscopy and flow cytometry. All three cell lines show to take up CdTe QDs via endocytosis. After arresting cells at specific phases with pharmacological agents, the cells in G2/M phase take up the most CdTe QDs, probably due to an increased membrane expansion during mitosis; whereas the cells in G1 phase do the least. A mathematical physics model was built to calculate the relative uptake rates of CdTe QDs by cells in different phases of the cell cycle, with the result as the uptake rate in G2/M phase is 2-4 times higher than that in G1 phase for these three cell lines. The results obtained from this study may provide the information useful for intracellular delivery of QDs.

  11. Synaptic interactions between perifornical lateral hypothalamic area, locus coeruleus nucleus and the oral pontine reticular nucleus are implicated in the stage succession during sleep-wakefulness cycle.

    Science.gov (United States)

    Tortorella, Silvia; Rodrigo-Angulo, Margarita L; Núñez, Angel; Garzón, Miguel

    2013-01-01

    The perifornical area in the posterior lateral hypothalamus (PeFLH) has been implicated in several physiological functions including the sleep-wakefulness regulation. The PeFLH area contains several cell types including those expressing orexins (Orx; also known as hypocretins), mainly located in the PeF nucleus. The aim of the present study was to elucidate the synaptic interactions between Orx neurons located in the PeFLH area and different brainstem neurons involved in the generation of wakefulness and sleep stages such as the locus coeruleus (LC) nucleus (contributing to wakefulness) and the oral pontine reticular nucleus (PnO) nucleus (contributing to REM sleep). Anatomical data demonstrated the existence of a neuronal network involving the PeFLH area, LC, and the PnO nuclei that would control the sleep-wake cycle. Electrophysiological experiments indicated that PeFLH area had an excitatory effect on LC neurons. PeFLH stimulation increased the firing rate of LC neurons and induced an activation of the EEG. The excitatory effect evoked by PeFLH stimulation in LC neurons was blocked by the injection of the Orx-1 receptor antagonist SB-334867 into the LC. Similar electrical stimulation of the PeFLH area evoked an inhibition of PnO neurons by activation of GABAergic receptors because the effect was blocked by bicuculline application into the PnO. Our data also revealed that the LC and PnO nuclei exerted a feedback control on neuronal activity of PeFLH area. Electrical stimulation of LC facilitated firing activity of PeFLH neurons by activation of catecholaminergic receptors whereas PnO stimulation inhibited PeFLH neurons by activation of GABAergic receptors. In conclusion, Orx neurons of the PeFLH area seem to be an important organizer of the wakefulness and sleep stages in order to maintain a normal succession of stages during the sleep-wakefulness cycle.

  12. Synaptic interactions between perifornical lateral hypothalamic area, locus coeruleus nucleus and the oral pontine reticular nucleus are implicated in the stage succession during sleep-wakefulness cycle

    Directory of Open Access Journals (Sweden)

    Angel eNunez

    2013-11-01

    Full Text Available The perifornical area in the posterior lateral hypothalamus (PeFLH has been implicated in several physiological functions including the sleep-wakefulness regulation. The PeFLH area contains several cell types including those expressing orexins (Orx; also known as hypocretins, mainly located in the PeF nucleus. The aim of the present study was to elucidate the synaptic interactions between Orx neurons located in the PeFLH area and different brainstem neurons involved in the generation of wakefulness and sleep stages such as the locus coeruleus (LC nucleus (contributing to wakefulness and the oral pontine reticular nucleus (PnO nucleus (contributing to REM sleepAnatomical data demonstrated the existence of a neuronal network involving the PeFLH area, LC and the PnO nuclei that would control the sleep-wake cycle. Electrophysiological experiments indicated that PeFLH area had an excitatory effect on LC neurons. PeFLH stimulation increased the firing rate of LC neurons and induced an activation of the EEG. The excitatory effect evoked by PeFLH stimulation in LC neurons was blocked by the injection of the Orx-1 receptor antagonist SB-334867 into the LC. Similar electrical stimulation of the PeFLH area evoked an inhibition of PnO neurons by activation of GABAergic receptors because the effect was blocked by bicuculline application into the PnO. Our data also revealed that the LC and PnO nuclei exerted a feedback control on neuronal activity of PeFLH area. Electrical stimulation of LC facilitated firing activity of PeFLH neurons by activation of catecholaminergic receptors whereas PnO stimulation inhibited PeFLH neurons by activation of GABAergic receptors. In conclusion, Orx neurons of the PeFLH area seem to be an important organizer of the wakefulness and sleep stages in order to maintain a normal succession of stages during the sleep-wakefulness cycle.

  13. Endothelial adhesion of synchronized gastric tumor cells changes during cell cycle transit and correlates with the expression level of CD44 splice variants

    Institute of Scientific and Technical Information of China (English)

    Anton Oertl; Jens Castein; Tobias Engl; Wolf-Dietrich Beecken; Dietger Jonas; Richard Melamed; Roman A. Blaheta

    2005-01-01

    AIM: To study adhesion capacity and CD44 expression of human gastric adenocarcinoma MKN45 cells at different stages of a first cell cycle.METHODS: MKN45 cells were synchronized by aphidicolin and assayed for adhesion to an endothelial cell (HUVEC)monolayer. Surface expression of CD44 and CD44 splice variants on MKN45 cells was evaluated by flow cytometry.Functional relevance of CD44 adhesion receptors was investigated by blocking studies using anti CD44 monoclonal antibodies or by hyaluronan digestion.RESULTS: Adhesion of MKN45 to HUVEC was increased during G2/M transit, after which adhesion returned to baseline levels with cell cycle completion. In parallel, CD44splice variants CD44v4, CD44v5, and CD44v7 were all upregulated on MKN45 during cell cycle progression with a maximum effect in G2/M. The function of CD44 surface receptors was assessed with specific receptor blocking monodonal antibodies or removal of hyaluronan by digestion with hyaluronidase. Both strategies inhibited tumor cell adhesion to HUVEC by nearly 50%, which indicates that MKN45-HUVEC-interaction is CD44 dependent.CONCLUSION: CD44 expression level is linked to the cell cycle in gastrointestinal tumor cells, which in turn leads to cell cyde dependent alterations of their adhesion behaviour to endothelium.

  14. FoxM1, a forkhead transcription factor is a master cell cycle regulator for mouse mature T cells but not double positive thymocytes.

    Directory of Open Access Journals (Sweden)

    Ling Xue

    Full Text Available FoxM1 is a forkhead box transcription factor and a known master regulator required for different phases of the cell cycle. In cell lines, FoxM1 deficient cells exhibit delayed S phase entry, aneuploidy, polyploidy and can't complete mitosis. In vivo, FoxM1 is expressed mostly in proliferating cells but is surprisingly also found in non-proliferating CD4(+CD8(+ double positive thymocytes. Here, we addressed the role of FoxM1 in T cell development by generating and analyzing two different lines of T-cell specific FoxM1 deficient mice. As expected, FoxM1 is required for proliferation of early thymocytes and activated mature T cells. Defective expression of many cell cycle proteins was detected, including cyclin A, cyclin B1, cdc2, cdk2, p27 and the Rb family members p107 and p130 but surprisingly not survivin. Unexpectedly, loss of FoxM1 only affects a few cell cycle proteins in CD4(+CD8(+ thymocytes and has little effect on their sensitivity to apoptosis and the subsequent steps of T cell differentiation. Thus, regulation of cell cycle genes by FoxM1 is stage- and context-dependent.

  15. Immunohistochemical study of pituitary cells in wild and captive Salminus hilarii (Characiformes: Characidae) females during the annual reproductive cycle.

    Science.gov (United States)

    Honji, Renato Massaaki; Nóbrega, Rafael Henrique; Pandolfi, Matias; Shimizu, Akio; Borella, Maria Inês; Moreira, Renata Guimarães

    2013-01-01

    Freshwater fish that live exclusively in rivers are at particular risk from fragmentation of the aquatic system, mainly the species that migrate upriver for reproduction. That is the case of Salminus hilarii, an important migratory species currently classified as "almost threatened" in the São Paulo State (Brazil), facing water pollution, dam construction, riparian habitat destruction and environmental changes that are even more serious in this State. Additionally, this species show ovulation dysfunction in captivity. Our studies focused on the identification and distribution of the pituitary cell types in the adenohypophysis of S. hilarii females, including a morphometric analysis that compares pituitary cells from wild and captive broodstocks during the reproductive annual cycle. The morphology of adenohypophysial cells showed differences following the reproductive cycle and the environment. In general, optical density suggested a higher cellular activity during the previtellogenic (growth hormone) and vitellogenic (somatolactin) stages in both environments. Additionally, the nucleus/cell ratio analysis suggested that growth hormone and somatolactin cells were larger in wild than in captive females in most reproductive stages of the annual cycle. In contrast, prolactin hormone showed no variation throughout the reproductive cycle (in both environments). Morphometrical analyses related to reproduction of S. hilarii in different environmental conditions, suggest that somatolactin and growth hormone play an important role in reproduction in teleost and can be responsible for the regulation of associated processes that indirectly affect reproductive status.

  16. Impairment of cell cycle progression by aflatoxin B1 in human cell lines.

    Science.gov (United States)

    Ricordy, R; Gensabella, G; Cacci, E; Augusti-Tocco, G

    2002-05-01

    Aflatoxin B1 is a mycotoxin produced by Aspergillus flavus and Aspergillus parasiticum, which may be present as a food contaminant. It is known to cause acute toxic effects and act as a carcinogenic agent. The carcinogenic action has been related to its ability to form unstable adducts with DNA, which represent possible mutagenic sites. On the other hand, the primary cellular target responsible for its toxic action has not yet been clearly identified. Previous data suggested a possible correlation between cell proliferation and responsiveness to aflatoxin toxicity. These observations led us to investigate the effect of the toxin on cell cycle progression of three human cell lines (HepG2, SK-N-MC and SK-N-SH derived from liver and nervous tissue tumours); they were shown to display different responses to toxin exposure and have different growth kinetics. We performed analysis of the cell cycle, DNA synthesis and expression of p21 and p53 in the presence and absence of the toxin in all cell lines exposed. The results of cell cycle cytofluorometric analysis show significant alterations of cell cycle progression as a result of toxin treatment. In all cell lines exposure to a 24 h toxin treatment causes a dose-dependent accumulation in S phase, however, the ability to recover from impairment to traverse S phase varies in the cell lines under study. SK-N-MC cells appear more prone to resume DNA synthesis when the toxin is removed, while the other two cell lines maintain a significant inhibition of DNA synthesis, as indicated by cytofluorimetry and [(3)H]dTR incorporation. The level of p53 and p21 expression in the three cell lines was examined by western blot analysis and significant differences were detected. The ready resumption of DNA synthesis displayed by SK-N-MC cells could possibly be related to the absence of p53 control of cell cycle progression.

  17. Genome-wide annotation, expression profiling, and protein interaction studies of the core cell-cycle genes in Phalaenopsis aphrodite.

    Science.gov (United States)

    Lin, Hsiang-Yin; Chen, Jhun-Chen; Wei, Miao-Ju; Lien, Yi-Chen; Li, Huang-Hsien; Ko, Swee-Suak; Liu, Zin-Huang; Fang, Su-Chiung

    2014-01-01

    Orchidaceae is one of the most abundant and diverse families in the plant kingdom and its unique developmental patterns have drawn the attention of many evolutionary biologists. Particular areas of interest have included the co-evolution of pollinators and distinct floral structures, and symbiotic relationships with mycorrhizal flora. However, comprehensive studies to decipher the molecular basis of growth and development in orchids remain scarce. Cell proliferation governed by cell-cycle regulation is fundamental to growth and development of the plant body. We took advantage of recently released transcriptome information to systematically isolate and annotate the core cell-cycle regulators in the moth orchid Phalaenopsis aphrodite. Our data verified that Phalaenopsis cyclin-dependent kinase A (CDKA) is an evolutionarily conserved CDK. Expression profiling studies suggested that core cell-cycle genes functioning during the G1/S, S, and G2/M stages were preferentially enriched in the meristematic tissues that have high proliferation activity. In addition, subcellular localization and pairwise interaction analyses of various combinations of CDKs and cyclins, and of E2 promoter-binding factors and dimerization partners confirmed interactions of the functional units. Furthermore, our data showed that expression of the core cell-cycle genes was coordinately regulated during pollination-induced reproductive development. The data obtained establish a fundamental framework for study of the cell-cycle machinery in Phalaenopsis orchids.

  18. The Hog1 MAP Kinase Promotes the Recovery from Cell Cycle Arrest Induced by Hydrogen Peroxide in Candida albicans.

    Science.gov (United States)

    Correia, Inês; Alonso-Monge, Rebeca; Pla, Jesús

    2016-01-01

    Eukaryotic cell cycle progression in response to environmental conditions is controlled via specific checkpoints. Signal transduction pathways mediated by MAPKs play a crucial role in sensing stress. For example, the canonical MAPKs Mkc1 (of the cell wall integrity pathway), and Hog1 (of the HOG pathway), are activated upon oxidative stress. In this work, we have analyzed the effect of oxidative stress induced by hydrogen peroxide on cell cycle progression in Candida albicans. Hydrogen peroxide was shown to induce a transient arrest at the G1 phase of the cell cycle. Specifically, a G1 arrest was observed, although phosphorylation of Mkc1 and Hog1 MAPKs can take place at all stages of the cell cycle. Interestingly, hog1 (but not mkc1) mutants required a longer time compared to wild type cells to resume growth after hydrogen peroxide challenge. Using GFP-labeled cells and mixed cultures of wild type and hog1 cells we were able to show that hog1 mutants progress faster through the cell cycle under standard growth conditions in the absence of stress (YPD at 37°C). Consequently, hog1 mutants exhibited a smaller cell size. The altered cell cycle progression correlates with altered expression of the G1 cyclins Cln3 and Pcl2 in hog1 cells compared to the wild type strain. In addition, Hgc1 (a hypha-specific G1 cyclin) as well as Cln3 displayed a different kinetics of expression in the presence of hydrogen peroxide in hog1 mutants. Collectively, these results indicate that Hog1 regulates the expression of G1 cyclins not only in response to oxidative stress, but also under standard growth conditions. Hydrogen peroxide treated cells did not show fluctuations in the mRNA levels for SOL1, which are observed in untreated cells during cell cycle progression. In addition, treatment with hydrogen peroxide prevented degradation of Sol1, an effect which was enhanced in hog1 mutants. Therefore, in C. albicans, the MAPK Hog1 mediates cell cycle progression in response to oxidative

  19. Magnolol causes alterations in the cell cycle in androgen insensitive human prostate cancer cells in vitro by affecting expression of key cell cycle regulatory proteins.

    Science.gov (United States)

    McKeown, Brendan T; McDougall, Luke; Catalli, Adriana; Hurta, Robert A R

    2014-01-01

    Prostate cancer, one of the most common cancers in the Western world, affects many men worldwide. This study investigated the effects of magnolol, a compound found in the roots and bark of the magnolia tree Magnolia officinalis, on the behavior of 2 androgen insensitive human prostate cancer cell lines, DU145 and PC3, in vitro. Magnolol, in a 24-h exposure at 40 and 80 μM, was found to be cytotoxic to cells. Magnolol also affected cell cycle progression of DU145 and PC3 cells, resulting in alterations to the cell cycle and subsequently decreasing the proportion of cells entering the G2/M-phase of the cell cycle. Magnolol inhibited the expression of cell cycle regulatory proteins including cyclins A, B1, D1, and E, as well as CDK2 and CDK4. Protein expression levels of pRBp107 decreased and pRBp130 protein expression levels increased in response to magnolol exposure, whereas p16(INK4a), p21, and p27 protein expression levels were apparently unchanged post 24-h exposure. Magnolol exposure at 6 h did increase p27 protein expression levels. This study has demonstrated that magnolol can alter the behavior of androgen insensitive human prostate cancer cells in vitro and suggests that magnolol may have potential as a novel anti-prostate cancer agent.

  20. Ground deformation cycles participating with sub-Plinian, Vulcanian eruptions, and a magma effusive stage at Kirishima volcanoes

    Science.gov (United States)

    Takeo, M.; Maehara, Y.; Ohminato, T.; Ichihara, M.; Oikawa, J.

    2012-12-01

    Volcanoes display several kinds of explosive eruptions, such as Plinian, sub-Plinian, Vulcanian, and Strombolian eruptions. The ground deformation data participating in explosive eruptions yield a fruitful knowledge about the dynamics of explosive eruptions. In this paper, we present tilt motions, near a summit crater during the 2011 eruption of Shinmoe-dake, Kirishima volcanoes, participated with the different kinds of volcanic activities, and make clear the characteristics of tilt motions and time sequences. The beginning period of volcanic activity at Shimoe-dake volcano in 2001 is divided into three different stages: the sub-Plinian stage (26-27 January 2011), the magma effusive stage (28-31 January 2011), and the Vulcanian stage (1-7 February 2011). During these three distinct stages, different kinds of tilt motions were observed participating with these activities. The sub-Plinian and the Vulcanian eruptions were preceded by inflations directed to the summit. A time sequence of the tilt ratio between NS component at KISH and that at SMN represents a gradual increment approaching the first sub-Plinian eruption on 26 January 2011: from 0.3 at 14:30 to 0.4 at 14:40. Employing a cylindrical pressure source in a conduit and taking into account the topography of Shinmoe-dake volcano in a calculation of tilts [Maeda et al., 2011], it became clear that the gradual increment of tilt ratio from 0.3 to 0.4 corresponds to the deepening of the source depth from 810 m to 710 m above sea level. The inflation-deflation cycles with the typical period of one hour were also recorded during the magma effusive stage; these cycles synchronized with volcanic tremors or long-period events in the last term of this stage. Almost all Vulcanian eruptions are preceded by step-like inflations. The tilt motions represented various time sequences after the inflations halted: no distinct tilt change until the Vulcanian eruption, gradual deflation preceding the Vulcanian eruption, and

  1. A Case Report for Stage ⅢB Squamous Cell Lung Carcinoma Patient Treated with Cultured Wild Ginseng Pharmacopuncture Therapy

    Directory of Open Access Journals (Sweden)

    Bong-Ky Park

    2007-12-01

    Full Text Available Objective : To derive further studies evaluating the effectiveness of Cultured Wild Ginseng Pharmacopuncture (CWGP Therapy on squamous cell carcinoma as a first line. Methods : Three cycles (4 weeks/cycle of CWGP were administered as a dosage of 10 ml per day. Patient was diagnosed with stage IIIB squamous cell carcinoma and refused all therapy of conventional medicine because of old age and cardiac invasion of tumor. Intensive treatment of CWGP for 3 cycles was done on the patient. Computed Topography (CT was performed to evaluate the therapeutic efficacy. Results : After the intravenous infusion of 2 cycles of CWGP, chest CT revealed the mass size and pleural invasion sustained stable disease. After the point injection of 1 cycle of CWGP, chest CT revealed progressive disease. The disease free survival rate was 1 month. Conclusion : This case may provide us the possibility that CWGP offers potential benefits for patients with squamous cell lung carcinoma. But this is a single case study and further case-series research should be compensated.

  2. The same, only different - DNA damage checkpoints and their reversal throughout the cell cycle

    NARCIS (Netherlands)

    Shaltiel, Indra A.; Krenning, Lenno; Bruinsma, Wytse; Medema, René H.

    2015-01-01

    Cell cycle checkpoints activated by DNA double-strand breaks (DSBs) are essential for the maintenance of the genomic integrity of proliferating cells. Following DNA damage, cells must detect the break and either transiently block cell cycle progression, to allow time for repair, or exit the cell cyc

  3. Berberine induces cell cycle arrest and apoptosis in human gastric carcinoma SNU-5 cell line

    Institute of Scientific and Technical Information of China (English)

    Jing-Pin Lin; Jai-Sing Yang; Jau-Hong Lee; Wen-Tsong Hsieh; Jing-Gung Chung

    2006-01-01

    AIM: To investigate the relationship between the inhibited growth (cytotoxic activity) of berberine and apoptotic pathway with its molecular mechanism of action.METHODS: The in vitro cytotoxic techniques were complemented by cell cycle analysis and determination of sub-G1 for apoptosis in human gastric carcinoma SNU-5 cells. Percentage of viable cells, cell cycle, and sub-G1 group (apoptosis) were examined and determined by the flow cytometric methods. The associated proteins for cell cycle arrest and apoptosis were examined by Western blotting.RESULTS: For SNU-5 cell line, the IC (50) was found to be 48 μmol/L of berberine. In SNU-5 cells treated with 25-200 μmol/L berberine, G2/M cell cycle arrest was observed which was associated with a marked increment of the expression of p53, Wee1 and CDk1 proteins and decreased cyclin B. A concentration-dependent decrease of cells in G0/G1 phase and an increase in G2/M phase were detected. In addition, apoptosis detected as sub-G0 cell population in cell cycle measurement was proved in 25-200 μmol/L berberine-treated cells by monitoring the apoptotic pathway. Apoptosis was identified by sub-G0 cell population, and upregulation of Bax, downregulation of Bcl-2, release of Ca2+, decreased the mitochondrial membrane potential and then led to the release of mitochondrial cytochrome C into the cytoplasm and caused the activation of caspase-3, and finally led to the occurrence of apoptosis.CONCLUSION: Berberine induces p53 expression and leads to the decrease of the mitochondrial membrane potential, Cytochrome C release and activation of caspase-3 for the induction of apoptosis.

  4. Producing fully ES cell-derived mice from eight-cell stage embryo injections.

    Science.gov (United States)

    DeChiara, Thomas M; Poueymirou, William T; Auerbach, Wojtek; Frendewey, David; Yancopoulos, George D; Valenzuela, David M

    2010-01-01

    In conventional methods for the generation of genetically modified mice, gene-targeted embryonic stem (ES) cells are injected into blastocyst-stage embryos or are aggregated with morula-stage embryos, which are then transferred to the uterus of a surrogate mother. F0 generation mice born from the embryos are chimeras composed of genetic contributions from both the modified ES cells and the recipient embryos. Obtaining a mouse strain that carries the gene-targeted mutation requires breeding the chimeras to transmit the ES cell genetic component through the germ line to the next (F1) generation (germ line transmission, GLT). To skip the chimera stage, we developed the VelociMouse method, in which injection of genetically modified ES cells into eight-cell embryos followed by maturation to the blastocyst stage and transfer to a surrogate mother produces F0 generation mice that are fully derived from the injected ES cells and exhibit a 100% GLT efficiency. The method is simple and flexible. Both male and female ES cells can be introduced into the eight-cell embryo by any method of injection or aggregation and using all ES cell and host embryo combinations from inbred, hybrid, and outbred genetic backgrounds. The VelociMouse method provides several unique opportunities for shortening project timelines and reducing mouse husbandry costs. First, as VelociMice exhibit 100% GLT, there is no need to test cross chimeras to establish GLT. Second, because the VelociMouse method permits efficient production of ES cell-derived mice from female ES cells, XO ES cell subclones, identified by screening for spontaneous loss of the Y chromosome, can be used to generate F0 females that can be bred with isogenic F0 males derived from the original targeted ES cell clone to obtain homozygous mutant mice in the F1 generation. Third, as VelociMice are genetically identical to the ES cells from which they were derived, the VelociMouse method opens up myriad possibilities for creating mice with

  5. Ethanol Metabolism Activates Cell Cycle Checkpoint Kinase, Chk2

    Science.gov (United States)

    Clemens, Dahn L.; Mahan Schneider, Katrina J.; Nuss, Robert F.

    2011-01-01

    Chronic ethanol abuse results in hepatocyte injury and impairs hepatocyte replication. We have previously shown that ethanol metabolism results in cell cycle arrest at the G2/M transition, which is partially mediated by inhibitory phosphorylation of the cyclin-dependent kinase, Cdc2. To further delineate the mechanisms by which ethanol metabolism mediates this G2/M arrest, we investigated the involvement of upstream regulators of Cdc2 activity. Cdc2 is activated by the phosphatase Cdc25C. The activity of Cdc25C can, in turn, be regulated by the checkpoint kinase, Chk2, which is regulated by the kinase ataxia telangiectasia mutated (ATM). To investigate the involvement of these regulators of Cdc2 activity, VA-13 cells, which are Hep G2 cells modified to efficiently express alcohol dehydrogenase, were cultured in the presence or absence of 25 mM ethanol. Immunoblots were performed to determine the effects of ethanol metabolism on the activation of Cdc25C, Chk2, and ATM. Ethanol metabolism increased the active forms of ATM, and Chk2, as well as the phosphorylated form of Cdc25C. Additionally, inhibition of ATM resulted in approximately 50% of the cells being rescued from the G2/M cell cycle arrest, and ameliorated the inhibitory phosphorylation of Cdc2. Our findings demonstrate that ethanol metabolism activates ATM. ATM can activate the checkpoint kinase Chk2, resulting in phosphorylation of Cdc25C, and ultimately in the accumulation of inactive Cdc2. This may, in part, explain the ethanol metabolism-mediated impairment in hepatocyte replication, which may be important in the initiation and progression of alcoholic liver injury. PMID:21924579

  6. Effect of ATRA on the expression of HOXA5 gene in K562 cells and its relationship with cell cycle and apoptosis.

    Science.gov (United States)

    Liu, Wen-Jun; Zhang, Teng; Guo, Qu-Lian; Liu, Chun-Yan; Bai, Yong-Qi

    2016-05-01

    Leukemia is the most common malignant disease in children with high incidence and mortality rates, and a poor treatment effect. The aim of the present study was to examine the changes in the expression of homeobox (Hox) A5 gene and its relationship with cell cycle and apoptosis through the intervention of human K562 myeloid leukemia cell line by all-trans retinoic acid (ATRA), to analyze the role of HOXA5 in the pathogenesis and development process of myeloid leukemia. The optimal concentration of ATRA to be used with K562 cells was determined using a cell counting kit‑8 (CCK‑8). After 24, 72 and 48 h following treatment of K562 cells with 10 µmol/l ATRA, cell cycle events and apoptosis were measured using flow cytometry. HOXA5 mRNA and protein expression in K562 cells was assessed by RT‑PCR and western blot analysis, and the relationship between HOXA5 expression and cell cycle and apoptosis was analyzed. The HOXA5 mRNA and protein expression levels were increased following treatment with ATRA in K562 cells. Apoptosis was increased significantly. The cell cycle was inhibited in G0/G1 phase. Cell proliferation was also inhibited. HOXA5 mRNA and protein expression rates positively correlated with cell apoptosis and the increased percentage and cell cycle of the G0/G1 phase. However, HOXA5 negatively correlated with the reduced percentage of S stage. In conclusion, the expression of HOXA5 in cells was increased following treatment with ATRA in K562 cells, in a time-dependent manner. Additionally, ATRA may inhibit the proliferation of K562 cells and promote apoptosis by upregulating the HOXA5 mRNA and protein expression.

  7. Cell cycle arrest by a gradient of Dpp signaling during Drosophila eye development

    Directory of Open Access Journals (Sweden)

    Bhattacharya Abhishek

    2010-03-01

    Full Text Available Abstract Background The secreted morphogen Dpp plays important roles in spatial regulation of gene expression and cell cycle progression in the developing Drosophila eye. Dpp signaling is required for timely cell cycle arrest ahead of the morphogenetic furrow as a prelude to differentiation, and is also important for eye disc growth. The dpp gene is expressed at multiple locations in the eye imaginal disc, including the morphogenetic furrow that sweeps across the eye disc as differentiation initiates. Results Studies of Brinker and Dad expression, and of Mad phosphorylation, establish that there is a gradient of Dpp signaling in the eye imaginal disc anterior to the morphogenetic furrow, predominantly in the anterior-posterior axis, and also Dpp signaling at the margins of the disc epithelium and in the dorsal peripodial membrane. Almost all signaling activity seems to spread through the plane of the epithelia, although peripodial epithelium cells can also respond to underlying disc cells. There is a graded requirement for Dpp signaling components for G1 arrest in the eye disc, with more stringent requirements further anteriorly where signaling is lower. The signaling level defines the cell cycle response, because elevated signaling through expression of an activated Thickveins receptor molecule arrested cells at more anterior locations. Very anterior regions of the eye disc were not arrested in response to activated receptor, however, and evidence is presented that expression of the Homothorax protein may contribute to this protection. By contrast to activated Thickveins, ectopic expression of processed Dpp leads to very high levels of Mad phosphorylation which appear to have non-physiological consequences. Conclusions G1 arrest occurs at a threshold level of Dpp signaling within a morphogen gradient in the anterior eye. G1 arrest is specific for one competent domain in the eye disc, allowing Dpp signaling to promote growth at earlier

  8. Analysis of cell cycle and replication of mouse macrophages after in vivo and in vitro Cryptococcus neoformans infection using laser scanning cytometry.

    Science.gov (United States)

    Coelho, Carolina; Tesfa, Lydia; Zhang, Jinghang; Rivera, Johanna; Gonçalves, Teresa; Casadevall, Arturo

    2012-04-01

    We investigated the outcome of the interaction of Cryptococcus neoformans with murine macrophages using laser scanning cytometry (LSC). Previous results in our lab had shown that phagocytosis of C. neoformans promoted cell cycle progression. LSC allowed us to simultaneously measure the phagocytic index, macrophage DNA content, and 5-ethynyl-2'-deoxyuridine (EdU) incorporation such that it was possible to study host cell division as a function of phagocytosis. LSC proved to be a robust, reliable, and high-throughput method for quantifying phagocytosis. Phagocytosis of C. neoformans promoted cell cycle progression, but infected macrophages were significantly less likely to complete mitosis. Hence, we report a new cytotoxic effect associated with intracellular C. neoformans residence that manifested itself in impaired cell cycle completion as a consequence of a block in the G(2)/M stage of the mitotic cell cycle. Cell cycle arrest was not due to increased cell membrane permeability or DNA damage. We investigated alveolar macrophage replication in vivo and demonstrated that these cells are capable of low levels of cell division in the presence or absence of C. neoformans infection. In summary, we simultaneously studied phagocytosis, the cell cycle state of the host cell and pathogen-mediated cytotoxicity, and our results demonstrate a new cytotoxic effect of C. neoformans infection on murine macrophages: fungus-induced cell cycle arrest. Finally, we provide evidence for alveolar macrophage proliferation in vivo.

  9. Induction of G1 cell cycle arrest and apoptosis by berberine in bladder cancer cells.

    Science.gov (United States)

    Yan, Keqiang; Zhang, Cheng; Feng, Jinbo; Hou, Lifang; Yan, Lei; Zhou, Zunlin; Liu, Zhaoxu; Liu, Cheng; Fan, Yidon; Zheng, Baozhong; Xu, Zhonghua

    2011-07-01

    Bladder cancer is the ninth most common type of cancer, and its surgery is always followed by chemotherapy to prevent recurrence. Berberine is non-toxic to normal cells but has anti-cancer effects in many cancer cell lines. This study was aimed to determine whether berberine inhibits the cell proliferation and induces cell cycle arrest and apoptosis in BIU-87 and T24 bladder cancer cell line. The superficial bladder cancer cell line BIU-87 and invasive T24 bladder cancer cells were treated with different concentrations of berberine. MTT assay was used to determine the effects of berberine on the viability of these cells. The cell cycle arrest was detected through propidium iodide (PI) staining. The induction of apoptosis was determined through Annexin V-conjugated Alexa Fluor 488 (Alexa488) staining. Berberine inhibited the viability of BIU-87 and T24 cells in a dose- and time-dependent manner. It also promoted cell cycle arrest at G0/G1 in a dose-dependent manner and induced apoptosis. We observed that H-Ras and c-fos mRNA and protein expressionswere dose-dependently and time-dependently decreased by berberine treatment. Also, we investigated the cleaved caspase-3 and caspase-9 protein expressions increased in a dose-dependent manner. Berberine inhibits the cell proliferation and induces cell cycle arrest and apoptosis in BIU-87, bladder cancer cell line and T24, invasive bladder cancer cell line. Berberine can inhibit the oncogentic H-Ras and c-fos in T24 cells, and can induce the activation of the caspase-3 and caspase-9 apoptosis. Therefore, berberine has the potential to be a novel chemotherapy drug to treat the bladder cancer by suppressing tumor growth.

  10. American cranberry (Vaccinium macrocarpon) extract affects human prostate cancer cell growth via cell cycle arrest by modulating expression of cell cycle regulators.

    Science.gov (United States)

    Déziel, Bob; MacPhee, James; Patel, Kunal; Catalli, Adriana; Kulka, Marianna; Neto, Catherine; Gottschall-Pass, Katherine; Hurta, Robert

    2012-05-01

    Prostate cancer is one of the most common cancers in the world, and its prevalence is expected to increase appreciably in the coming decades. As such, more research is necessary to understand the etiology, progression and possible preventative measures to delay or to stop the development of this disease. Recently, there has been interest in examining the effects of whole extracts from commonly harvested crops on the behaviour and progression of cancer. Here, we describe the effects of whole cranberry extract (WCE) on the behaviour of DU145 human prostate cancer cells in vitro. Following treatment of DU145 human prostate cancer cells with 10, 25 and 50 μg ml⁻¹ of WCE, respectively for 6 h, WCE significantly decreased the cellular viability of DU145 cells. WCE also decreased the proportion of cells in the G2-M phase of the cell cycle and increased the proportion of cells in the G1 phase of the cell cycle following treatment of cells with 25 and 50 μg ml⁻¹ treatment of WCE for 6 h. These alterations in cell cycle were associated with changes in cell cycle regulatory proteins and other cell cycle associated proteins. WCE decreased the expression of CDK4, cyclin A, cyclin B1, cyclin D1 and cyclin E, and increased the expression of p27. Changes in p16(INK4a) and pRBp107 protein expression levels also were evident, however, the changes noted in p16(INK4a) and pRBp107 protein expression levels were not statistically significant. These findings demonstrate that phytochemical extracts from the American cranberry (Vaccinium macrocarpon) can affect the behaviour of human prostate cancer cells in vitro and further support the potential health benefits associated with cranberries.

  11. Mechanism of T-oligo-induced cell cycle arrest in Mia-Paca pancreatic cancer cells

    Science.gov (United States)

    Rankin, Andrew M.; Sarkar, Sibaji; Faller, Douglas V.

    2011-01-01

    DNA oligonucleotides with sequence homology to human telomeric DNA (T-oligo) induce cell cycle arrest, followed by apoptosis, senescence, or autophagy in a human cancer cell type-specific manner. T-oligo has potential as a new therapeutic strategy in oncology because of its ability to target certain types of tumor cells while sparing normal ones. In the present study, we demonstrate the T-oligo-induced S-phase cell cycle arrest in four pancreatic cancer cell lines. To further contribute to the mechanistic understanding of T-oligo, we also identify cyclin dependent kinase 2 (cdk2) as a functional mediator in the T-oligo-induced cell cycle arrest of pancreatic cancer cells. Ectopic expression of a constitutively-active cdk2 mutant abrogates T-oligo-induced cell cycle arrest in these tumor cells while knockdown of cdk2 expression alone recapitulates the T-oligo effect. Finally, we demonstrate the dispensability of T-oligo-induced ATM/ATR-mediated DNA damage response-signaling pathways, which have long been considered functional in the T-oligo signaling mechanism. PMID:21898405

  12. The AhR is involved in the regulation of LoVo cell proliferation through cell cycle-associated proteins.

    Science.gov (United States)

    Yin, Jiuheng; Sheng, Baifa; Han, Bin; Pu, Aimin; Yang, Kunqiu; Li, Ping; Wang, Qimeng; Xiao, Weidong; Yang, Hua

    2016-05-01

    Some ingredients in foods can activate the aryl hydrocarbon receptor (AhR) and arrest cell proliferation. In this study, we hypothesized that 6-formylindolo [3, 2-b] carbazole (FICZ) arrests the cell cycle in LoVo cells (a colon cancer line) through the AhR. The AhR agonist FICZ and the AhR antagonist CH223191 were used to treat LoVo cells. Real-time PCR and Western blot analyses were performed to detect the expression of the AhR, CYP1A1, CDK4, cyclinD1, cyclin E, CDK2, P27, and pRb. The distribution and activation of the AhR were detected with immunofluorescence. A 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometric analysis were performed to measure cell viability, cell cycle stage, and apoptosis. Our results show that FICZ inhibited LoVo cell proliferation by inducing G1 cell cycle arrest but had no effect on epithelial apoptosis. Further analysis found that FICZ downregulated cyclinD1 and upregulated p27 expression to arrest Rb phosphorylation. The downregulation of cyclinD1 and upregulation of p27 were abolished by co-treatment with CH223191. We conclude that the AhR, when activated by FICZ (an endogenous AhR ligand), can arrest the cell cycle and block LoVo cell proliferation.

  13. Regulation of the G1 phase of the mammalian cell cycle

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In any multi-cellular organism, the balance between cell division and cell death maintains a constant cell num ber. Both cell division cycle and cell death are highly regulated events. Whether the cell will proceed through the cycle or not, depends upon whether the conditions re quired at the checkpoints during the cycle are filfilled. In higher eucaryotic cells, such as mammalian cells, signals that arrest the cycle usually act at a G1 checkpoint. Cells that pass this restriction point are committed to complete the cycle. Regulation of the G1 phase of the cell cycle is extremely complex and involves many different families of proteins such as retinoblastoma family, cyclin dependent kinases, cyclins, and cyclin kinase inhibitors.

  14. S-phase-dependent cell cycle disturbances caused by Aleutian mink disease parvovirus

    DEFF Research Database (Denmark)

    Oleksiewicz, M.B.; Alexandersen, Søren

    1997-01-01

    We examined replication of the autonomous parovirus Aleutian mink disease parovirus (ADV) in relation to cell cycle progression of permissive Crandell feline kidney (CRFK) cells. Flow cytometric analysis showed that ADV caused a composite, binary pattern of cell cycle arrest. ADV-induced cell cycle...... with subthreshold levels of ADV products through the late S/G(2) block and, consequently, that the binary pattern of ADV-induced cell cycle arrest may be governed merely by viral replication levels within a single S phase. Flow cytometric analysis of propidium iodide fluorescence and bromodeoxyuridine uptake showed...... that population A cells sustained significantly higher levels of DNA replication than population B cells during the ADV-induced cell cycle arrest. Therefore, the type of ADV-induced cell cycle arrest was not trivial and could have implications for subsequent viral replication in the target cell....

  15. Two stage bioethanol refining with multi litre stacked microbial fuel cell and microbial electrolysis cell.

    Science.gov (United States)

    Sugnaux, Marc; Happe, Manuel; Cachelin, Christian Pierre; Gloriod, Olivier; Huguenin, Gérald; Blatter, Maxime; Fischer, Fabian

    2016-12-01

    Ethanol, electricity, hydrogen and methane were produced in a two stage bioethanol refinery setup based on a 10L microbial fuel cell (MFC) and a 33L microbial electrolysis cell (MEC). The MFC was a triple stack for ethanol and electricity co-generation. The stack configuration produced more ethanol with faster glucose consumption the higher the stack potential. Under electrolytic conditions ethanol productivity outperformed standard conditions and reached 96.3% of the theoretically best case. At lower external loads currents and working potentials oscillated in a self-synchronized manner over all three MFC units in the stack. In the second refining stage, fermentation waste was converted into methane, using the scale up MEC stack. The bioelectric methanisation reached 91% efficiency at room temperature with an applied voltage of 1.5V using nickel cathodes. The two stage bioethanol refining process employing bioelectrochemical reactors produces more energy vectors than is possible with today's ethanol distilleries.

  16. INTEGRATED GASIFICATION COMBINED CYCLE PROJECT 2 MW FUEL CELL DEMONSTRATION

    Energy Technology Data Exchange (ETDEWEB)

    FuelCell Energy

    2005-05-16

    With about 50% of power generation in the United States derived from coal and projections indicating that coal will continue to be the primary fuel for power generation in the next two decades, the Department of Energy (DOE) Clean Coal Technology Demonstration Program (CCTDP) has been conducted since 1985 to develop innovative, environmentally friendly processes for the world energy market place. The 2 MW Fuel Cell Demonstration was part of the Kentucky Pioneer Energy (KPE) Integrated Gasification Combined Cycle (IGCC) project selected by DOE under Round Five of the Clean Coal Technology Demonstration Program. The participant in the CCTDP V Project was Kentucky Pioneer Energy for the IGCC plant. FuelCell Energy, Inc. (FCE), under subcontract to KPE, was responsible for the design, construction and operation of the 2 MW fuel cell power plant. Duke Fluor Daniel provided engineering design and procurement support for the balance-of-plant skids. Colt Engineering Corporation provided engineering design, fabrication and procurement of the syngas processing skids. Jacobs Applied Technology provided the fabrication of the fuel cell module vessels. Wabash River Energy Ltd (WREL) provided the test site. The 2 MW fuel cell power plant utilizes FuelCell Energy's Direct Fuel Cell (DFC) technology, which is based on the internally reforming carbonate fuel cell. This plant is capable of operating on coal-derived syngas as well as natural gas. Prior testing (1992) of a subscale 20 kW carbonate fuel cell stack at the Louisiana Gasification Technology Inc. (LGTI) site using the Dow/Destec gasification plant indicated that operation on coal derived gas provided normal performance and stable operation. Duke Fluor Daniel and FuelCell Energy developed a commercial plant design for the 2 MW fuel cell. The plant was designed to be modular, factory assembled and truck shippable to the site. Five balance-of-plant skids incorporating fuel processing, anode gas oxidation, heat recovery

  17. Effect of silencing HOXA5 gene expression using RNA interference on cell cycle and apoptosis in Jurkat cells.

    Science.gov (United States)

    Huang, Hui-Ping; Liu, Wen-Jun; Guo, Qu-Lian; Bai, Yong-Qi

    2016-03-01

    Acute lymphocytic leukemia (ALL) is a common malignant tumor with a high morbidity rate among children, accounting for approximately 80% of leukemia cases. Although there have been improvements in the treatment of patients frequent relapse lead to a poor prognosis. The aim of the present study was to determine whether HOXA5 may be used as a target for gene therapy in leukemia in order to provide a new treatment. Mononuclear cells were extracted from the bone marrow according to the clinical research aims. After testing for ALL in the acute stage, the relative mRNA and protein expression of HOXA5 was detected in the ALL remission groups (n=25 cases per group) and the control group [n=20 cases, immune thrombocytopenia (ITP)]. Gene silencing by RNA interference (RNAi) was used to investigate the effect of silencing HOXA5 after small interfering RNA (siRNA) transfection to Jurkat cells. The HOXA5-specific siRNA was transfected to Jurkat cells using lipofectamine. The experiment was divided into the experimental group (liposomal transfection of HOXA5 targeting siRNA), the negative control group (liposomal transfection of cells with negative control siRNA) and the control group (plus an equal amount of cells and culture media only). Western blotting and quantitative fluorescent polymerase chain reaction (QF‑PCR) were used to detect the relative HOXA5 mRNA expression and protein distribution in each cell group. Cell distribution in the cell cycle and the rate of cells undergoing apoptosis were determined using flow cytometry. The expression of HOXA5 at the mRNA and protein levels in the acute phase of ALL was significantly higher than that in ALL in the remission and control groups. In cells transfected with HOXA5-specific siRNA, the expression of HOXA5 at the mRNA and protein levels decreased significantly (Pcells in the cell cycle was also altered. Specifically, more cells were present in the G0/G1 phase compared to the S phase (Pcells transfected with HOXA5

  18. DNA Damage, Cell Cycle Arrest, and Apoptosis Induction Caused by Lead in Human Leukemia Cells.

    Science.gov (United States)

    Yedjou, Clement G; Tchounwou, Hervey M; Tchounwou, Paul B

    2015-12-22

    In recent years, the industrial use of lead has been significantly reduced from paints and ceramic products, caulking, and pipe solder. Despite this progress, lead exposure continues to be a significant public health concern. The main goal of this research was to determine the in vitro mechanisms of lead nitrate [Pb(NO₃)₂] to induce DNA damage, apoptosis, and cell cycle arrest in human leukemia (HL-60) cells. To reach our goal, HL-60 cells were treated with different concentrations of Pb(NO₃)₂ for 24 h. Live cells and necrotic death cells were measured by the propidium idiode (PI) assay using the cellometer vision. Cell apoptosis was measured by the flow cytometry and DNA laddering. Cell cycle analysis was evaluated by the flow cytometry. The result of the PI demonstrated a significant (p cell death in Pb(NO₃)₂-treated cells, indicative of membrane rupture by Pb(NO₃)₂ compared to the control. Data generated from the comet assay indicated a concentration-dependent increase in DNA damage, showing a significant increase (p cells (apoptotic cells) compared to the control. The flow cytometry assessment also indicated Pb(NO₃)₂ exposure caused cell cycle arrest at the G₀/G₁ checkpoint. The result of DNA laddering assay showed presence of DNA smear in the agarose gel with little presence of DNA fragments in the treated cells compared to the control. In summary, Pb(NO₃)₂ inhibits HL-60 cells proliferation by not only inducing DNA damage and cell cycle arrest at the G₀/G₁ checkpoint but also triggering the apoptosis through caspase-3 activation and nucleosomal DNA fragmentation accompanied by secondary necrosis. We believe that our study provides a new insight into the mechanisms of Pb(NO₃)₂ exposure and its associated adverse health effects.

  19. Pterins in human hair follicle cells and in the synchronized murine hair cycle.

    Science.gov (United States)

    Schallreuter, K U; Beazley, W D; Hibberts, N A; Tobin, D J; Paus, R; Wood, J M

    1998-10-01

    Human dermal papilla cells (HDPC) express mRNA for the key enzymes for de novo synthesis/recycling and regulation of the pterin (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (6BH4). HDPC had significantly higher enzyme activities and 6BH4 levels in a comparative study with dermal fibroblasts, epidermal melanocytes, and keratinocytes under in vitro conditions. In addition, a significantly more rapid uptake of 14C-L-phenylalanine was demonstrated in HDPC compared with fibroblasts, whereas the differences in turnover to L-tyrosine were insignificant, suggesting a pooling of L-phenylalanine in HDPC. These results suggested that HDPC driven 6BH4 synthesis could be of major functional importance in the hair cycle. In order to follow this hypothesis in vivo, expression of enzyme activities and levels of the produced cofactor during the synchronized hair cycle were determined employing the murine model C57BL/6. These data revealed a significantly increased de novo synthesis for 6BH4 via GTP-cyclohydrolase I concomitant with high levels of 6BH4, and the induction of phenylalanine hydroxylase activities during the telogen/early anagen stage (days 0-1). Pterin levels and enzyme activities fall on day 3 and plateau during the rest of the entire cycle. In addition, thioredoxin reductase and glutathione reductase activities were measured, where the latter enzyme remained constant but thioredoxin reductase activities showed a biphasic behavior. The first peak coincided with the induction of 6BH4 de novo synthesis at the beginning of the hair cycle. The second peak was observed at mid-anagen, when melanogenesis takes place. Taken together, our results show the presence of autocrine pterin synthesis/recycling in human hair follicle cells under in vitro conditions, and a possible role for 6BH4 in the synchronized murine hair cycle.

  20. Metformin and phenformin deplete tricarboxylic acid cycle and glycolytic intermediates during cell transformation and NTPs in cancer stem cells.

    Science.gov (United States)

    Janzer, Andreas; German, Natalie J; Gonzalez-Herrera, Karina N; Asara, John M; Haigis, Marcia C; Struhl, Kevin

    2014-07-22

    Metformin, a first-line diabetes drug linked to cancer prevention in retrospective clinical analyses, inhibits cellular transformation and selectively kills breast cancer stem cells (CSCs). Although a few metabolic effects of metformin and the related biguanide phenformin have been investigated in established cancer cell lines, the global metabolic impact of biguanides during the process of neoplastic transformation and in CSCs is unknown. Here, we use LC/MS/MS metabolomics (>200 metabolites) to assess metabolic changes induced by metformin and phenformin in an Src-inducible model of cellular transformation and in mammosphere-derived breast CSCs. Although phenformin is the more potent biguanide in both systems, the metabolic profiles of these drugs are remarkably similar, although not identical. During the process of cellular transformation, biguanide treatment prevents the boost in glycolytic intermediates at a specific stage of the pathway and coordinately decreases tricarboxylic acid (TCA) cycle intermediates. In contrast, in breast CSCs, biguanides have a modest effect on glycolytic and TCA cycle intermediates, but they strongly deplete nucleotide triphosphates and may impede nucleotide synthesis. These metabolic profiles are consistent with the idea that biguanides inhibit mitochondrial complex 1, but they indicate that their metabolic effects differ depending on the stage of cellular transformation.

  1. Analysis of chlorophyll fluorescence reveals stage specific patterns of chloroplast-containing cells during Arabidopsis embryogenesis.

    Science.gov (United States)

    Tejos, Ricardo I; Mercado, Ana V; Meisel, Lee A

    2010-01-01

    The basic body plan of a plant is established early in embryogenesis when cells differentiate, giving rise to the apical and basal regions of the embryo. Using chlorophyll fluorescence as a marker for chloroplasts, we have detected specific patterns of chloroplast-containing cells at specific stages of embryogenesis. Non-randomly distributed chloroplast-containing cells are seen as early as the globular stage of embryogenesis in Arabidopsis. In the heart stage of embryogenesis, chloroplast containing cells are detected in epidermal cells as well as a central region of the heart stage embryo, forming a triangular septum of chloroplast-containing cells that divides the embryo into three equal sectors. Torpedo stage embryos have chloroplast-containing epidermal cells and a central band of chloroplast-containing cells in the cortex layer, just below the shoot apical meristem. In the walking-stick stage of embryogenesis, chloroplasts are present in the epidermal, cortex and endodermal cells. The chloroplasts appear reduced or absent from the provascular and columella cells of walking-stick stage embryos. These results suggest that there is a tight regulation of plastid differentiation during embryogenesis that generates specific patterns of chloroplast-containing cells in specific cell layers at specific stages of embryogenesis.

  2. Robust synchronization of coupled circadian and cell cycle oscillators in single mammalian cells.

    Science.gov (United States)

    Bieler, Jonathan; Cannavo, Rosamaria; Gustafson, Kyle; Gobet, Cedric; Gatfield, David; Naef, Felix

    2014-07-15

    Circadian cycles and cell cycles are two fundamental periodic processes with a period in the range of 1 day. Consequently, coupling between such cycles can lead to synchronization. Here, we estimated the mutual interactions between the two oscillators by time-lapse imaging of single mammalian NIH3T3 fibroblasts during several days. The analysis of thousands of circadian cycles in dividing cells clearly indicated that both oscillators tick in a 1:1 mode-locked state, with cell divisions occurring tightly 5 h before the peak in circadian Rev-Erbα-YFP reporter expression. In principle, such synchrony may be caused by either unidirectional or bidirectional coupling. While gating of cell division by the circadian cycle has been most studied, our data combined with stochastic modeling unambiguously show that the reverse coupling is predominant in NIH3T3 cells. Moreover, temperature, genetic, and pharmacological perturbations showed that the two interacting cellular oscillators adopt a synchronized state that is highly robust over a wide range of parameters. These findings have implications for circadian function in proliferative tissues, including epidermis, immune cells, and cancer.

  3. CtIP is regulated by the APC/C-Cdh1 to mediate cell cycle-dependent control of DNA repair

    NARCIS (Netherlands)

    de Boer, Harmen R.; Lafranchi, Lorenzo; Neugebauer, Christine; Fehrmann, Rudolf; de Vries, Elisabeth G. E.; Sartori, Alessandro A.; van Vugt, Marcel

    2014-01-01

    Human cells have evolved elaborate mechanisms for responding to DNA damage to maintain genome stability and prevent carcinogenesis. For instance, the cell cycle can be arrested at different stages to allow time for DNA repair. The APC/C-Cdh1 ubiquitin ligase regulates mitotic exit but is also implic

  4. Transcript profiling of individual twin blastomeres derived by splitting two-cell stage murine embryos.

    Science.gov (United States)

    Roberts, R Michael; Katayama, Mika; Magnuson, Scott R; Falduto, Michael T; Torres, Karen E O

    2011-03-01

    In invertebrates and amphibians, informational macromolecules in egg cytoplasm are organized to provide direction to the formation of embryonic lineages, but it is unclear whether vestiges of such prepatterning exist in mammals. Here we examined whether twin blastomeres from 2-cell stage mouse embryos differ in mRNA content. mRNA from 26 blastomeres derived from 13 embryos approximately mid-way through their second cell cycle was subjected to amplification. Twenty amplified samples were hybridized to arrays. Of those samples that hybridized successfully, 12 samples in six pairs were used in the final analysis. Probes displaying normalized values >0.25 (n = 4573) were examined for consistent bias in expression within blastomere pairs. Although transcript content varied between both individual embryos and twin blastomeres, no consistent asymmetries were observed for the majority of genes, with only 178 genes displaying a >1.4-fold difference in expression across all six pairs. Although class discovery clustering showed that blastomere pairs separated into two distinct groups in terms of their differentially expressed genes, when the data were tested for significance of asymmetrical expression, only 39 genes with >1.4-fold change ratios in six of six blastomere pairs passed the two-sample t-test (P < 0.05). Transcripts encoding proteins implicated in RNA processing and cytoskeletal organization were among the most abundant, differentially distributed mRNA, suggesting that a stochastically based lack of synchrony in cell cycle progression between the two cells might explain at least some and possibly all of the asymmetries in transcript composition.

  5. Identification of Cell Cycle Dependent Interaction Partners of the Septins by Quantitative Mass Spectrometry.

    Directory of Open Access Journals (Sweden)

    Christian Renz

    Full Text Available The septins are a conserved family of GTP-binding proteins that, in the baker's yeast, assemble into a highly ordered array of filaments at the mother bud neck. These filaments undergo significant structural rearrangements during the cell cycle. We aimed at identifying key components that are involved in or regulate the transitions of the septins. By combining cell synchronization and quantitative affinity-purification mass-spectrometry, we performed a screen for specific interaction partners of the septins at three distinct stages of the cell cycle. A total of 83 interaction partners of the septins were assigned. Surprisingly, we detected DNA-interacting/nuclear proteins and proteins involved in ribosome biogenesis and protein synthesis predominantly present in alpha-factor arrested that do not display an assembled septin structure. Furthermore, two distinct sets of regulatory proteins that are specific for cells at S-phase with a stable septin collar or at mitosis with split septin rings were identified. Complementary methods like SPLIFF and immunoprecipitation allowed us to more exactly define the spatial and temporal characteristics of selected hits of the AP-MS screen.

  6. Cell mass and cell cycle dynamics of an asynchronous budding yeast population

    DEFF Research Database (Denmark)

    Lencastre Fernandes, Rita; Carlquist, Magnus; Lundin, Luisa

    2013-01-01

    consumption observed during batch cultivation. The good agreement between the proposed multi-scale model (a population balance model [PBM] coupled to an unstructured model) and experimental data (both the overall physiology and cell size and cell cycle distributions) indicates that a mechanistic model...... of model predictions for cell property distributions against experimental data is scarce. This study focuses on the experimental and mathematical description of the dynamics of cell size and cell cycle position distributions, of a population of Saccharomyces cerevisiae, in response to the substrate......Despite traditionally regarded as identical, cells in a microbial cultivation present a distribution of phenotypic traits, forming a heterogeneous cell population. Moreover, the degree of heterogeneity is notably enhanced by changes in micro-environmental conditions. A major development...

  7. Life cycle assessment as decision support tool in early stage development of a new technology for wastewater resource recovery

    DEFF Research Database (Denmark)

    Fang, Linda L.; Valverde Perez, Borja; Damgaard, Anders

    2015-01-01

    results of the first simulated full-scale TRENS system in its potential operating environment as a side-stream process to an existing Copenhagen wastewater treatment plant. The system recovers water and nutrients that can be used in scenarios of agricultural irrigation-fertilization and aquifer recharge......Life cycle assessment (LCA) has been increasingly used in the field of wastewater treatment where the focus has been to identify environmental trade-offs of current technologies. In a novel approach, we use LCA to support early stage research and development of a biochemical system for wastewater...... resource recovery. The freshwater and nutrient content of wastewater are to a large extent recognized as potential valuable resources that can be recovered for beneficial reuse. Both recovery and reuse are intended to address existing environmental concerns, for example water scarcity and use of non...

  8. Timing robustness in the budding and fission yeast cell cycles.

    KAUST Repository

    Mangla, Karan

    2010-02-01

    Robustness of biological models has emerged as an important principle in systems biology. Many past analyses of Boolean models update all pending changes in signals simultaneously (i.e., synchronously), making it impossible to consider robustness to variations in timing that result from noise and different environmental conditions. We checked previously published mathematical models of the cell cycles of budding and fission yeast for robustness to timing variations by constructing Boolean models and analyzing them using model-checking software for the property of speed independence. Surprisingly, the models are nearly, but not totally, speed-independent. In some cases, examination of timing problems discovered in the analysis exposes apparent inaccuracies in the model. Biologically justified revisions to the model eliminate the timing problems. Furthermore, in silico random mutations in the regulatory interactions of a speed-independent Boolean model are shown to be unlikely to preserve speed independence, even in models that are otherwise functional, providing evidence for selection pressure to maintain timing robustness. Multiple cell cycle models exhibit strong robustness to timing variation, apparently due to evolutionary pressure. Thus, timing robustness can be a basis for generating testable hypotheses and can focus attention on aspects of a model that may need refinement.

  9. Host cell kinases and the hepatitis C virus life cycle.

    Science.gov (United States)

    Colpitts, Che C; Lupberger, Joachim; Doerig, Christian; Baumert, Thomas F

    2015-10-01

    Hepatitis C virus (HCV) infection relies on virus-host interactions with human hepatocytes, a context in which host cell kinases play critical roles in every step of the HCV life cycle. During viral entry, cellular kinases, including EGFR, EphA2 and PKA, regulate the localization of host HCV entry factors and induce receptor complex assembly. Following virion internalization, viral genomes replicate on endoplasmic reticulum-derived membranous webs. The formation of membranous webs depends on interactions between the HCV NS5a protein and PI4KIIIα. The phosphorylation status of NS5a, regulated by PI4KIIIα, CKI and other kinases, also acts as a molecular switch to virion assembly, which takes place on lipid droplets. The formation of lipid droplets is enhanced by HCV activation of IKKα. In view of the multiple crucial steps in the viral life cycle that are mediated by host cell kinases, these enzymes also represent complementary targets for antiviral therapy. This article is part of a Special Issue entitled: Inhibitors of Protein Kinases.

  10. Silicon Phthalocyanine 4 and Photodynamic Therapy in Stage IA-IIA Cutaneous T-Cell Non-Hodgkin Lymphoma

    Science.gov (United States)

    2015-12-03

    Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Stage I Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IA Mycosis Fungoides/Sezary Syndrome; Stage IB Mycosis Fungoides/Sezary Syndrome; Stage II Cutaneous T-cell Non-Hodgkin Lymphoma; Stage IIA Mycosis Fungoides/Sezary Syndrome

  11. Genistein sensitizes ovarian carcinoma cells to chemotherapy by switching the cell cycle progression in vitro

    Institute of Scientific and Technical Information of China (English)

    Huang Yanhong; Yuan Peng; Zhang Qinghong; Xin Xiaoyan

    2009-01-01

    Objective: To address how genistein sensitizes the chemotherapy-resistant ovarian carcinoma cells and promotes apoptosis in the respect of cell cycle and the regulation of survivin expression in the process. Methods: Ovarian SKOV-3 carcinoma cell line was treated with genistein or cisplatin either alone or in combination. Cell viability was showed by MTT method. Cell cycle and apoptosis were detected by flow cytometry. Survivin mRNA and protein were revealed by RT-PCR and immunocytochemistry, respectively. Results: Genistein could reduce the cell viability in a dose-dependent manner, while cisplatin did so at a much higher level. In contrast, if the two agents were treated in combination, half growth inhibition (IC50) value for cisplatin was reduced remarkably and the effect was synergistic as analyzed by isobologram. In particular, the reduced cell viability was exhibited by a switch in cell cycle progression, as the cells were arrested in G2/M phase and the G0/G1 phase-fraction was significantly decreased. The reduced cell viability appeared to involve apoptosis, based on our results from flow cytometry and Hoechst 33258 staining. In the meanwhile, genistein performed the inhibitory effect on cisplatin-induced survivin expression. Conclusion: Genistein can sensitize ovarian carcinoma cells to cisplatin therapy with the inhibition of survivin expression as the potential mechanism.

  12. Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest.

    Science.gov (United States)

    Ohtsuka, Toshiyuki; Shizu, Yoko; Nishiwaki, Ai; Yashiro, Yuichiro; Koizumi, Hiroshi

    2010-07-01

    Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.

  13. Andrographolide inhibits hepatoma cells growth and affects the expression of cell cycle related proteins.

    Science.gov (United States)

    Shen, Kai-Kai; Liu, Tian-Yu; Xu, Chong; Ji, Li-Li; Wang, Zheng-Tao

    2009-09-01

    The present study is aimed to investigate the toxic effects of andrographolide (Andro) on hepatoma cells and elucidate its preliminary mechanisms. After cells were treated with different concentrations of Andro (0-50 micromol x L(-1)) for 24 h, cell viability was evaluated with 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, after hepatoma cells (Hep3B and HepG2) were treated with different concentrations of Andro (0-30 micromol x L(-1)) for 14 d, the number of colony formation was accounted under microscope. Cell cycle related proteins such as Cdc-2, phosphorylated-Cdc-2, Cyclin B and Cyclin D1 were detected with Western blotting assay and the cell cycle was analyzed by flow cytometry using propidium iodide staining. MTT results showed that Andro induced growth inhibition of hepatoma cells in a concentration-dependent manner but had no significant effects on human normal liver L-02 cells. Andro dramatically decreased the colony formation of hepatoma cells in the concentration-dependent manner. Moreover, Andro induced a decrease of Hep3B cells at the G0-G1 phase and a concomitant accumulation of cells at G2-M phase. At the molecular level, Western blotting results showed that Andro decreased the expression of Cdc-2, phosphorylated-Cdc-2, Cyclin D1 and Cyclin B proteins in a time-dependent manner, which are all cell cycle related proteins. Taken together, the results demonstrated that Andro specifically inhibited the growth of hepatoma cells and cellular cell cycle related proteins were possibly involved in this process.

  14. Albumin Suppresses Human Hepatocellular Carcinoma Proliferation and the Cell Cycle

    Directory of Open Access Journals (Sweden)

    Shunsuke Nojiri

    2014-03-01

    Full Text Available Many investigations have revealed that a low recurrence rate of hepatocellular carcinoma (HCC is associated with high serum albumin levels in patients; therefore, high levels of serum albumin are a major indicator of a favorable prognosis. However, the mechanism inhibiting the proliferation of HCC has not yet been elucidated, so we investigated the effect of serum albumin on HCC cell proliferation. Hep3B was cultured in MEM with no serum or containing 5 g/dL human albumin. As control samples, Prionex was added to generate the same osmotic pressure as albumin. After 24-h incubation, the expressions of α-fetoprotein (AFP, p53, p21, and p57 were evaluated with real-time PCR using total RNA extracted from the liver. Protein expressions and the phosphorylation of Rb (retinoblastoma were determined by Western blot analysis using total protein extracted from the liver. For flow cytometric analysis of the cell cycle, FACS analysis was performed. The percentages of cell cycle distribution were evaluated by PI staining, and all samples were analyzed employing FACScalibur (BD with appropriate software (ModFit LT; BD. The cell proliferation assay was performed by counting cells with using a Scepter handy automated cell counter (Millipore. The mRNA levels of AFP relative to Alb(−: Alb(−, Alb(+, and Prionex, were 1, 0.7 ± 0.2 (p < 0.001 for Alb(−, and 1 ± 0.3, respectively. The mRNA levels of p21 were 1, 1.58 ± 0.4 (p = 0.007 for Alb(− and p = 0.004 for Prionex, and 0.8 ± 0.2, respectively. The mRNA levels of p57 were 1, 4.4 ± 1.4 (p = 0.002 for Alb(− and Prionex, and 1.0 ± 0.1, respectively. The protein expression levels of Rb were similar in all culture media. The phosphorylation of P807/811 and P780 of Rb protein was reduced in Alb(+. More cells in the G0/G1 phase and fewer cells in S and G2/M phases were obtained in Alb(+ than in Alb(− (G0/G1: 60.9%, 67.7%, 61.5%; G2/M: 16.5%, 13.1%, 15.6%; S: 22.6%, 19.2%, 23.0%, Alb(−, Alb

  15. Effects of silver nanoparticles on the freshwater snail Physa acuta: The role of test media and snails' life cycle stage.

    Science.gov (United States)

    F Gonçalves, Sandra; D Pavlaki, Maria; Lopes, Rafael; Hammes, Julia; Gallego-Urrea, Julián Alberto; Hassellöv, Martin; Jurkschat, Kerstin; Crossley, Alison; Loureiro, Susana

    2017-01-01

    Silver nanoparticles (AgNPs) are widely used worldwide, most likely leading to their release into the environment and a subsequent increase of environmental concentrations. Studies of their deleterious effects on organisms is crucial to understand their environmental impacts. The freshwater snail Physa acuta was chosen to evaluate the potential deleterious effects of AgNPs and their counterpart AgNO3 , through water-only exposures. The toxicity of AgNPs is greatly influenced by medium composition. Thus, 2 media were tested: artificial pond water (APW) and modified APW (adapted by removing calcium chloride). Acute tests (96 h) were performed with juvenile and adult snails in both media to assess lethality, and egg mass chronic tests were conducted with APW medium only to assess embryo viability and mortality, carried out until 90% hatching success was reached in the control. Acute toxicity increased with decreasing shell length for both silver forms (ion and nanoparticle); that is, juveniles were more sensitive than adults. Different test media led to dissimilar median lethal concentrations, with chloride playing an important role in toxicity, most likely by complexation with silver ions, which would reduce the bioavailability, uptake, and toxicity of silver. Chronic tests showed that hatching success was more sensitive to silver in the ionic form than in the particulate form. Different forms of silver, exposure media, and life cycle stages led to different patterns of toxicity, highlighting an impairment in the snails' life cycle. Environ Toxicol Chem 2017;36:243-253. © 2016 SETAC.

  16. Live-cell monitoring of periodic gene expression in synchronous human cells identifies Forkhead genes involved in cell cycle control.

    Science.gov (United States)

    Grant, Gavin D; Gamsby, Joshua; Martyanov, Viktor; Brooks, Lionel; George, Lacy K; Mahoney, J Matthew; Loros, Jennifer J; Dunlap, Jay C; Whitfield, Michael L

    2012-08-01

    We developed a system to monitor periodic luciferase activity from cell cycle-regulated promoters in synchronous cells. Reporters were driven by a minimal human E2F1 promoter with peak expression in G1/S or a basal promoter with six Forkhead DNA-binding sites with peak expression at G2/M. After cell cycle synchronization, luciferase activity was measured in live cells at 10-min intervals across three to four synchronous cell cycles, allowing unprecedented resolution of cell cycle-regulated gene expression. We used this assay to screen Forkhead transcription factors for control of periodic gene expression. We confirmed a role for FOXM1 and identified two novel cell cycle regulators, FOXJ3 and FOXK1. Knockdown of FOXJ3 and FOXK1 eliminated cell cycle-dependent oscillations and resulted in decreased cell proliferation rates. Analysis of genes regulated by FOXJ3 and FOXK1 showed that FOXJ3 may regulate a network of zinc finger proteins and that FOXK1 binds to the promoter and regulates DHFR, TYMS, GSDMD, and the E2F binding partner TFDP1. Chromatin immunoprecipitation followed by high-throughput sequencing analysis identified 4329 genomic loci bound by FOXK1, 83% of which contained a FOXK1-binding motif. We verified that a subset of these loci are activated by wild-type FOXK1 but not by a FOXK1 (H355A) DNA-binding mutant.

  17. Effect of Docosahexaenoic Acid on Cell Cycle Pathways in Breast Cell Lines With Different Transformation Degree.

    Science.gov (United States)

    Rescigno, Tania; Capasso, Anna; Tecce, Mario Felice

    2016-06-01

    n-3 polyunsaturated fatty acids (PUFAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), abundant in fish, have been shown to affect development and progression of some types of cancer, including breast cancer. The aim of our study was to further analyze and clarify the effects of these nutrients on the molecular mechanisms underlying breast cancer. Following treatments with DHA we examined cell viability, death, cell cycle, and some molecular effects in breast cell lines with different transformation, phenotypic, and biochemical characteristics (MCF-10A, MCF-7, SK-BR-3, ZR-75-1). These investigations showed that DHA is able to affect cell viability, proliferation, and cell cycle progression in a different way in each assayed breast cell line. The activation of ERK1/2 and STAT3 pathways and the expression and/or activation of molecules involved in cell cycle regulation such as p21(Waf1/Cip1) and p53, are very differently regulated by DHA treatments in each cell model. DHA selectively: (i) arrests non tumoral MCF-10A breast cells in G0 /G1 cycle phase, activating p21(Waf1/Cip1) , and p53, (ii) induces to death highly transformed breast cells SK-BR-3, reducing ERK1/2 and STAT3 phosphorylation and (iii) only slightly affects each analyzed process in MCF-7 breast cell line with transformation degree lower than SK-BR-3 cells. These findings suggest a more relevant inhibitory role of DHA within early development and late progression of breast cancer cell transformation and a variable effect in the other phases, depending on individual molecular properties and degree of malignancy of each clinical case.

  18. Glucose capped silver nanoparticles induce cell cycle arrest in HeLa cells.

    Science.gov (United States)

    Panzarini, Elisa; Mariano, Stefania; Vergallo, Cristian; Carata, Elisabetta; Fimia, Gian Maria; Mura, Francesco; Rossi, Marco; Vergaro, Viviana; Ciccarella, Giuseppe; Corazzari, Marco; Dini, Luciana

    2017-02-20

    This study aims to determine the interaction (uptake and biological effects on cell viability and cell cycle progression) of glucose capped silver nanoparticles (AgNPs-G) on human epithelioid cervix carcinoma (HeLa) cells, in relation to amount, 2×10(3) or 2×10(4) NPs/cell, and exposure time, up to 48h. The spherical and well dispersed AgNPs (30±5nm) were obtained by using glucose as reducing agent in a green synthesis method that ensures to stabilize AgNPs avoiding cytotoxic soluble silver ions Ag(+) release. HeLa cells take up abundantly and rapidly AgNPs-G resulting toxic to cells in amount and incubation time dependent manner. HeLa cells were arrested at S and G2/M phases of the cell cycle and subG1 population increased when incubated with 2×10(4) AgNPs-G/cell. Mitotic index decreased accordingly. The dissolution experiments demonstrated that the observed effects were due only to AgNPs-G since glucose capping prevents Ag(+) release. The AgNPs-G influence on HeLa cells viability and cell cycle progression suggest that AgNPs-G, alone or in combination with chemotherapeutics, may be exploited for the development of novel antiproliferative treatment in cancer therapy. However, the possible influence of the cell cycle on cellular uptake of AgNPs-G and the mechanism of AgNPs entry in cells need further investigation.

  19. Population structure and maturity stages of Fritillaria borealis (Appendicularia, Tunicata: seasonal cycle in Ushuaia Bay (Beagle Channel

    Directory of Open Access Journals (Sweden)

    María Laura Presta

    2015-09-01

    Full Text Available AbstractFritillaria borealis is a cosmopolitan species, very frequent in sub-antarctic and antarctic waters. The objective of this paper was to analyze its size structure and maturity stages at two sites in Ushuaia Bay: a coastal site exposed to anthropogenic pressure (E1 and a reference site (E2 located in the external zone of the bay. Zooplankton was collected during the 2012 seasonal cycle. The sampling method involved the use of a 67 µm-mesh net. Appendicularians were classified in four maturity stages: I undifferentiated gonads, II testis and ovary differentiated, III expanded testis, IV discharged testis, expanded ovary. Our results showed that the highest densities of F. borealisoccurred in spring and summer at both sites; coinciding with high values of chlorophyll-a. The percentage of juveniles (I and II exhibited a spatial and temporal pattern similar to that observed for chlorophyll-a values. During spring-summer, juveniles and mature specimens (III and IV showed a greater gonadal development than those individuals found in autumn-winter. In conclusion, the mismatching in the population structure and the pattern of densities of F. borealis between coastal and external zones would suggest the existence of two sub-populations susceptible to the influence of the anthropogenic impact in the bay.

  20. Stromal interaction molecule 1 regulates growth, cell cycle, and apoptosis of human tongue squamous carcinoma cells.

    Science.gov (United States)

    Cui, Xiaobo; Song, Laixiao; Bai, Yunfei; Wang, Yaping; Wang, Boqian; Wang, Wei

    2017-04-30

    Oral tongue squamous cell carcinoma (OTSCC) is the most common type of oral carcinomas. However, the molecular mechanism by which OTSCC developed is not fully identified. Stromal interaction molecule 1 (STIM1) is a transmembrane protein, mainly located in the endoplasmic reticulum (ER). STIM1 is involved in several types of cancers. Here, we report that STIM1 contributes to the development of human OTSCC. We knocked down STIM1 in OTSCC cell line Tca-8113 with lentivirus-mediated shRNA and found that STIM1 knockdown repressed the proliferation of Tca-8113 cells. In addition, we also showed that STIM1 deficiency reduced colony number of Tca-8113 cells. Knockdown of STIM1 repressed cells to enter M phase of cell cycle and induced cellular apoptosis. Furthermore, we performed microarray and bioinformatics analysis and found that STIM1 was associated with p53 and MAPK pathways, which may contribute to the effects of STIM1 on cell growth, cell cycle, and apoptosis. Finally, we confirmed that STIM1 controlled the expression of MDM2, cyclin-dependent kinase 4 (CDK4), and growth arrest and DNA damage inducible α (GADD45A) in OTSCC cells. In conclusion, we provide evidence that STIM1 contributes to the development of OTSCC partially through regulating p53 and MAPK pathways to promote cell cycle and survival.

  1. Cycle life test and failure model of nickel-hydrogen cells

    Science.gov (United States)

    Smithrick, J. J.

    1983-01-01

    Six ampere hour individual pressure vessel nickel hydrogen cells were charge/discharge cycled to failure. Failure as used here is defined to occur when the end of discharge voltage degraded to 0.9 volts. They were cycled under a low earth orbit cycle regime to a deep depth of discharge (80 percent of rated ampere hour capacity). Both cell designs were fabricated by the same manufacturer and represent current state of the art. A failure model was advanced which suggests both cell designs have inadequate volume tolerance characteristics. The limited existing data base at a deep depth of discharge (DOD) was expanded. Two cells of each design were cycled. One COMSAT cell failed at cycle 1712 and the other failed at cycle 1875. For the Air Force/Hughes cells, one cell failed at cycle 2250 and the other failed at cycle 2638. All cells, of both designs, failed due to low end of discharge voltage (0.9 volts). No cell failed due to electrical shorts. After cell failure, three different reconditioning tests (deep discharge, physical reorientation, and open circuit voltage stand) were conducted on all cells of each design. A fourth reconditioning test (electrolyte addition) was conducted on one cell of each design. In addition post cycle cell teardown and failure analysis were performed on the one cell of each design which did not have electrolyte added after failure. Previously announced in STAR as N83-25038

  2. Mechanisms involved in ceramide-induced cell cycle arrest in human hepatocarcinoma cells

    Institute of Scientific and Technical Information of China (English)

    Jing Wang; Xiao-Wen Lv; Jie-Ping Shi; Xiao-Song Hu

    2007-01-01

    AIM:To investigate the effect of ceramide on the cell cycle in human hepatocarcinoma Bel7402 cells.Possible molecular mechanisms were explored.METHODS:[3-(4,5)-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide(MTT)assay,plasmid transfection,reporter assay,FACS and Western blotting analyses were employed to investigate the effect and the related molecular mechanisms of C2-ceramide on the cell cycle of Bel7402 cells.RESULTS:C2-ceramide was found to inhibit the growth of Bel7402 cells by inducing cell cycle arrest.During the process,the expression of p21 protein increased,while that of cyclinD1,phospho-ERK1/2 and c-myc decreased.Furthermore,the level of CDK7 was downregulated,while the transcriptional activity of PPARγ was upregulated.Addition of GW9662,which is a PPARγ specific antagonist,could reserve the modulation action on CDK7.CONCLUSION:Our results support the hypothesis that cell cycle arrest induced by C2-ceramide may be mediated via accumulation of p21 and reduction of cyclinD1 and CDK7,at least partly,through PPARγ activation.The ERK signaling pathway was involved in this process.

  3. Discovery of a Splicing Regulator Required for Cell Cycle Progression

    Energy Technology Data Exchange (ETDEWEB)

    Suvorova, Elena S.; Croken, Matthew; Kratzer, Stella; Ting, Li-Min; Conde de Felipe, Magnolia; Balu, Bharath; Markillie, Lye Meng; Weiss, Louis M.; Kim, Kami; White, Michael W.

    2013-02-01

    In the G1 phase of the cell division cycle, eukaryotic cells prepare many of the resources necessary for a new round of growth including renewal of the transcriptional and protein synthetic capacities and building the machinery for chromosome replication. The function of G1 has an early evolutionary origin and is preserved in single and multicellular organisms, although the regulatory mechanisms conducting G1 specific functions are only understood in a few model eukaryotes. Here we describe a new G1 mutant from an ancient family of apicomplexan protozoans. Toxoplasma gondii temperature-sensitive mutant 12-109C6 conditionally arrests in the G1 phase due to a single point mutation in a novel protein containing a single RNA-recognition-motif (TgRRM1). The resulting tyrosine to asparagine amino acid change in TgRRM1 causes severe temperature instability that generates an effective null phenotype for this protein when the mutant is shifted to the restrictive temperature. Orthologs of TgRRM1 are widely conserved in diverse eukaryote lineages, and the human counterpart (RBM42) can functionally replace the missing Toxoplasma factor. Transcriptome studies demonstrate that gene expression is downregulated in the mutant at the restrictive temperature due to a severe defect in splicing that affects both cell cycle and constitutively expressed mRNAs. The interaction of TgRRM1 with factors of the tri-SNP complex (U4/U6 & U5 snRNPs) indicate this factor may be required to assemble an active spliceosome. Thus, the TgRRM1 family of proteins is an unrecognized and evolutionarily conserved class of splicing regulators. This study demonstrates investigations into diverse unicellular eukaryotes, like the Apicomplexa, have the potential to yield new insights into important mechanisms conserved across modern eukaryotic kingdoms.

  4. Transcription of ribosomal RNA genes is initiated in the third cell cycle of bovine embryos

    DEFF Research Database (Denmark)

    Jakobsen, Anne Sørig; Avery, Birthe; Dieleman, Steph J.

    2006-01-01

    polymerase I. In conclusion, rRNA transcription is initiated during the third cell cycle at a low level in both in vivo developed and in vitro produced bovine embryos. Transcription seems to be interrupted during the G1 phase of the fourth cell cycle, but reinitiates in the late half of the cycle...

  5. Mechanisms involved in alternariol-induced cell cycle arrest

    Energy Technology Data Exchange (ETDEWEB)

    Solhaug, A., E-mail: Anita.Solhaug@vetinst.no [Norwegian Veterinary Institute, Oslo (Norway); Vines, L.L. [Michigan State University, Department of Food Science and Human Nutrition, East Lansing, MI (United States); Ivanova, L.; Spilsberg, B. [Norwegian Veterinary Institute, Oslo (Norway); Holme, J.A. [Norwegian Institute of Public Health, Division of Environmental Medicine, Oslo (Norway); Pestka, J. [Michigan State University, Department of Food Science and Human Nutrition, East Lansing, MI (United States); Collins, A. [University of Oslo, Department of Nutrition, Faculty of Medicine, Oslo (Norway); Eriksen, G.S. [Norwegian Veterinary Institute, Oslo (Norway)

    2012-10-15

    Alternariol (AOH), a mycotoxin produced by Alternaria sp, is often found as a contaminant in fruit and cereal products. Here we employed the murine macrophage cell line RAW 264.7 to test the hypothesis that AOH causes toxicity as a response to DNA damage. AOH at concentrations of 15-30 {mu}M almost completely blocked cell proliferation. Within 30 min treatment, AOH (30 {mu}M) significantly increased the level of reactive oxygen species (ROS). Furthermore, DNA base oxidations as well as DNA strand breaks and/or alkaline labile sites were detected by the comet assay after 2 h exposure of AOH. Cell death (mostly necrosis) was observed after prolonged exposure to the highest concentration of AOH (60 {mu}M for 24 and 48 h) in our study. The DNA damage response involved phosphorylation (activation) of histone H2AX and check point kinase-1- and 2 (Chk-1/2). Moreover, AOH activated p53 and increased the expression of p21, Cyclin B, MDM2, and Sestrin 2; likewise the level of several miRNA was affected. AOH-induced Sestrin 2 expression was regulated by p53 and could at least partly be inhibited by antioxidants, suggesting a role of ROS in the response. Interestingly, the addition of antioxidants did not inhibit cell cycle arrest. Although the formation of ROS by itself was not directly linked cell proliferation, AOH-induced DNA damage and resulting transcriptional changes in p21, MDM2, and Cyclin B likely contribute to the reduced cell proliferation; while Sestrin 2 would contribute to the oxidant defense.

  6. Meiotic and Mitotic Cell Cycle Mutants Involved in Gametophyte Development in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Jingjing Liu; Li-Jia Qu

    2008-01-01

    The alternation between diploid and haploid generations is fundamentalin the life cycles of both animals and plants.The meiotic cell cycle is common to both animals and plants gamete formation, but in animals the products of meiosis are gametes,whereas for most plants,subsequent mitotic cell cycles are needed for their formation. Clarifying the regulatory mechanisms of mitotic cell cycle progression during gametophyte development will help understanding of sexual reproduction in plants.Many mutants defective in gametophyte development and,in particular,many meiotic and mitotic cell cycle mutants in Arabidopsis male and female gametophyte development were identified through both forward and reverse genetics approaches.

  7. Induction of cell-mediated immunity during early stages of infection with intracellular protozoa

    Directory of Open Access Journals (Sweden)

    Gazzinelli R.T.

    1998-01-01

    Full Text Available Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI maintained by Th1 lymphocytes and IFN-g. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serves as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are their obligatory niche in the vertebrate host. Recent reports show that the initiation of IL-12 synthesis by macrophages during these parasitic infections is a key event in regulating CMI and disease outcome. The studies reviewed here indicate that activation/inhibition of distinct signaling pathways and certain macrophage functions by intracellular protozoa are important events in inducing/modulating the immune response of their vertebrate hosts, allowing parasite and host survival and therefore maintaining parasite life cycles.

  8. Quantitative imaging with Fucci and mathematics to uncover temporal dynamics of cell cycle progression.

    Science.gov (United States)

    Saitou, Takashi; Imamura, Takeshi

    2016-01-01

    Cell cycle progression is strictly coordinated to ensure proper tissue growth, development, and regeneration of multicellular organisms. Spatiotemporal visualization of cell cycle phases directly helps us to obtain a deeper understanding of controlled, multicellular, cell cycle progression. The fluorescent ubiquitination-based cell cycle indicator (Fucci) system allows us to monitor, in living cells, the G1 and the S/G2/M phases of the cell cycle in red and green fluorescent colors, respectively. Since the discovery of Fucci technology, it has found numerous applications in the characterization of the timing of cell cycle phase transitions under diverse conditions and various biological processes. However, due to the complexity of cell cycle dynamics, understanding of specific patterns of cell cycle progression is still far from complete. In order to tackle this issue, quantitative approaches combined with mathematical modeling seem to be essential. Here, we review several studies that attempted to integrate Fucci technology and mathematical models to obtain quantitative information regarding cell cycle regulatory patterns. Focusing on the technological development of utilizing mathematics to retrieve meaningful information from the Fucci producing data, we discuss how the combined methods advance a quantitative understanding of cell cycle regulation.

  9. A NGS approach to the encrusting Mediterranean sponge Crella elegans (Porifera, Demospongiae, Poecilosclerida): transcriptome sequencing, characterization and overview of the gene expression along three life cycle stages.

    Science.gov (United States)

    Pérez-Porro, A R; Navarro-Gómez, D; Uriz, M J; Giribet, G

    2013-05-01

    Sponges can be dominant organisms in many marine and freshwater habitats where they play essential ecological roles. They also represent a key group to address important questions in early metazoan evolution. Recent approaches for improving knowledge on sponge biological and ecological functions as well as on animal evolution have focused on the genetic toolkits involved in ecological responses to environmental changes (biotic and abiotic), development and reproduction. These approaches are possible thanks to newly available, massive sequencing technologies-such as the Illumina platform, which facilitate genome and transcriptome sequencing in a cost-effective manner. Here we present the first NGS (next-generation sequencing) approach to understanding the life cycle of an encrusting marine sponge. For this we sequenced libraries of three different life cycle stages of the Mediterranean sponge Crella elegans and generated de novo transcriptome assemblies. Three assemblies were based on sponge tissue of a particular life cycle stage, including non-reproductive tissue, tissue with sperm cysts and tissue with larvae. The fourth assembly pooled the data from all three stages. By aggregating data from all the different life cycle stages we obtained a higher total number of contigs, contigs with blast hit and annotated contigs than from one stage-based assemblies. In that multi-stage assembly we obtained a larger number of the developmental regulatory genes known for metazoans than in any other assembly. We also advance the differential expression of selected genes in the three life cycle stages to explore the potential of RNA-seq for improving knowledge on functional processes along the sponge life cycle.

  10. Change of the cell cycle after flutamide treatment in prostate cancer cells and its molecular mechanism

    Institute of Scientific and Technical Information of China (English)

    Yong Wang; Wei-Jun Qin; He Wang; Guo-Xing Shao; Chen Shao; Chang-Hong Shi; Lei Zhang; Hong-Hong Yue; Peng-Fei Wang; Bo Yang; Yun-Tao Zhang; Fan Liu

    2005-01-01

    Aim: To explore the effect of androgen receptor (AR) on the expression of the cell cycle-related genes, such as CDKN1A and BTG1, in prostate cancer cell line LNCaP. Methods: After AR antagonist flutamide treatment and confirmation of its effect by phase contrast microscope and flow cytometry, the differential expression of the cell cycle-related genes was analyzed by a cDNA microarray. The flutamide treated cells were set as the experimental group and the LNCaP cells as the control. We labeled cDNA probes of the experimental group and control group with Cy5 and Cy3 dyes, respectively, through reverse transcription. Then we hybridized the cDNA probes with cDNA microarrays, which contained 8 126 unique human cDNA sequences and the chip was scanned to get the fluorescent values of Cy5 and Cy3 on each spot. After primary analysis, reverse transcription polymerase chain reaction (RTPCR) tests were carried out to confirm the results of the chips. Results:After AR antagonist flutamide treatment,three hundred and twenty-six genes (3.93 %) expressed differentially, 97 down-regulated and 219 up-regulated.Among them, eight up-regulated genes might be cell cycle-related, namely CDC10, NRAS, BTG1, Weel, CLK3,DKFZP564A122, CDKN1A and BTG2. The CDKN1A and BTG1 gene mRNA expression was confirmed to be higher in the experimental group by RT-PCR, whilep53 mRNA expression had no significant changes. Conclusion: Flutamide treatment might up-regulate CDKN1A and BTG1 expression in prostate cancer cells. The protein expressions of CDKN1A and BTG1 play an important role in inhibiting the proliferation of cancer cells. CDKN1A has a great impact on the cell cycle of prostate cancer cells and may play a role in the cancer cells in a p53-independent pathway. The prostate cancer cells might affect the cell cycle-related genes by activating AR and thus break the cell cycle control.

  11. Tcf3 and cell cycle factors contribute to butyrate resistance in colorectal cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Chiaro, Christopher, E-mail: cchiaro@tcmedc.org [Department of Basic Sciences, The Commonwealth Medical College, 525 Pine Street, Scranton, PA 18509 (United States); Lazarova, Darina L., E-mail: dlazarova@tcmedc.org [Department of Basic Sciences, The Commonwealth Medical College, 525 Pine Street, Scranton, PA 18509 (United States); Bordonaro, Michael, E-mail: mbordonaro@tcmedc.org [Department of Basic Sciences, The Commonwealth Medical College, 525 Pine Street, Scranton, PA 18509 (United States)

    2012-11-09

    Highlights: Black-Right-Pointing-Pointer We investigate mechanisms responsible for butyrate resistance in colon cancer cells. Black-Right-Pointing-Pointer Tcf3 modulates butyrate's effects on Wnt activity and cell growth in resistant cells. Black-Right-Pointing-Pointer Tcf3 modulation of butyrate's effects differ by cell context. Black-Right-Pointing-Pointer Cell cycle factors are overexpressed in the resistant cells. Black-Right-Pointing-Pointer Reversal of altered gene expression can enhance the anti-cancer effects of butyrate. -- Abstract: Butyrate, a fermentation product of dietary fiber, inhibits clonal growth in colorectal cancer (CRC) cells dependent upon the fold induction of Wnt activity. We have developed a CRC cell line (HCT-R) that, unlike its parental cell line, HCT-116, does not respond to butyrate exposure with hyperactivation of Wnt signaling and suppressed clonal growth. PCR array analyses revealed Wnt pathway-related genes, the expression of which differs between butyrate-sensitive HCT-116 CRC cells and their butyrate-resistant HCT-R cell counterparts. We identified overexpression of Tcf3 as being partially responsible for the butyrate-resistant phenotype, as this DNA-binding protein suppresses the hyperinduction of Wnt activity by butyrate. Consequently, Tcf3 knockdown in HCT-R cells restores their sensitivity to the effects of butyrate on Wnt activity and clonal cell growth. Interestingly, the effects of overexpressed Tcf3 differ between HCT-116 and HCT-R cells; thus, in HCT-116 cells Tcf3 suppresses proliferation without rendering the cells resistant to butyrate. In HCT-R cells, however, the overexpression of Tcf3 inhibits Wnt activity, and the cells are still able to proliferate due to the higher expression levels of cell cycle factors, particularly those driving the G{sub 1} to S transition. Knowledge of the molecular mechanisms determining the variable sensitivity of CRC cells to butyrate may assist in developing approaches that

  12. Imaging Nuclear Morphology and Organization in Cleared Plant Tissues Treated with Cell Cycle Inhibitors.

    Science.gov (United States)

    de Souza Junior, José Dijair Antonino; de Sa, Maria Fatima Grossi; Engler, Gilbert; Engler, Janice de Almeida

    2016-01-01

    Synchronization of root cells through chemical treatment can generate a large number of cells blocked in specific cell cycle phases. In plants, this approach can be employed for cell suspension cultures and plant seedlings. To identify plant cells in the course of the cell cycle, especially during mitosis in meristematic tissues, chemical inhibitors can be used to block cell cycle progression. Herein, we present a simplified and easy-to-apply protocol to visualize mitotic figures, nuclei morphology, and organization in whole Arabidopsis root apexes. The procedure is based on tissue clearing, and fluorescent staining of nuclear DNA with DAPI. The protocol allows carrying out bulk analysis of nuclei and cell cycle phases in root cells and will be valuable to investigate mutants like overexpressing lines of genes disturbing the plant cell cycle.

  13. Sequential chemoradiotherapy for stage I/II nasal natural killer/T cell lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Young Joo [Ulsan University Hospital, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Ahn, Yong Chan; Kim, Won Seog; Ko, Young Hyeh [Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2004-09-15

    Authors would report the results of sequential CHOP chemotherapy (cyclophosphamide, adriamycin, vincristine, and prednisone) and involved field radiotherapy (IFRT) for early stage nasal natural killer/T-cell lymphoma (NKTCL). Fourteen among 17 patients, who were registered at the Samsung Medical Center tumor registry with stage I and II nasal NKTCL from March 1995 to December 1999 received this treatment protocol. Three to four cycles of CHOP chemotherapy were given at 3 weeks' interval, which was followed by local IFRT including the known tumor extent and the adjacent draining lymphatics. Favorable responses after chemotherapy (before IFRT) were achievable only in seven patients (5 CR's + 2 PR's: 50%), while seven patients showed disease progression. There were six patients with local failures, two with distant relapses, and none with regional lymphatic failure. The actuarial overall survival and progression-free survival at 3 years were 50.0% and 42.9%. All the failures and deaths occurred within 13 months of the treatment start. The factors that correlated with the improved survival were the absence of 'B' symptoms, the favorable response to chemotherapy and overall treatment, and the low risk by international prognostic index on univariate analyses. Compared with the historic treatment results by IFRT either alone or followed by chemotherapy, the current trial failed to demonstrate advantages with respect to the failure pattern and survival. Development of new treatment strategy in combining IFRT and chemotherapy is required for improving outcomes.

  14. Cell-cycle regulation of formin-mediated actin cable assembly.

    Science.gov (United States)

    Miao, Yansong; Wong, Catherine C L; Mennella, Vito; Michelot, Alphée; Agard, David A; Holt, Liam J; Yates, John R; Drubin, David G

    2013-11-19

    Assembly of appropriately oriented actin cables nucleated by formin proteins is necessary for many biological processes in diverse eukaryotes. However, compared with knowledge of how nucleation of dendritic actin filament arrays by the actin-related protein-2/3 complex is regulated, the in vivo regulatory mechanisms for actin cable formation are less clear. To gain insights into mechanisms for regulating actin cable assembly, we reconstituted the assembly process in vitro by introducing microspheres functionalized with the C terminus of the budding yeast formin Bni1 into extracts prepared from yeast cells at different cell-cycle stages. EM studies showed that unbranched actin filament bundles were reconstituted successfully in the yeast extracts. Only extracts enriched in the mitotic cyclin Clb2 were competent for actin cable assembly, and cyclin-dependent kinase 1 activity was indispensible. Cyclin-dependent kinase 1 activity also was found to regulate cable assembly in vivo. Here we present evidence that formin cell-cycle regulation is conserved in vertebrates. The use of the cable-reconstitution system to test roles for the key actin-binding proteins tropomyosin, capping protein, and cofilin provided important insights into assembly regulation. Furthermore, using mass spectrometry, we identified components of the actin cables formed in yeast extracts, providing the basis for comprehensive understanding of cable assembly and regulation.

  15. DUBbing cancer: Deubiquitylating enzymes involved in epigenetics, DNA damage and the cell cycle as therapeutic targets

    Directory of Open Access Journals (Sweden)

    Benedikt M Kessler

    2016-07-01

    Full Text Available Controlling cell proliferation is one of the hallmarks of cancer. A number of critical checkpoints ascertain progression through the different stages of the cell cycle, which can be aborted when perturbed, for instance by errors in DNA replication and repair. These molecular checkpoints are regulated by a number of proteins that need to be present at the right time and quantity. The ubiquitin system has emerged as a central player controlling the fate and function of such molecules such as cyclins, oncogenes and components of the DNA repair machinery. In particular, proteases that cleave ubiquitin chains, referred to as deubiquitylating enzymes (DUBs, have attracted recent attention due to their accessibility to modulation by small molecules. In this review, we describe recent evidence of the critical role of DUBs in aspects of cell cycle checkpoint control, associated DNA repair mechanisms and regulation of transcription, representing pathways altered in cancer. Therefore, DUBs involved in these processes emerge as potentially critical targets for the treatment of not only hematological, but potentially also solid tumors.

  16. DUBbing Cancer: Deubiquitylating Enzymes Involved in Epigenetics, DNA Damage and the Cell Cycle As Therapeutic Targets.

    Science.gov (United States)

    Pinto-Fernandez, Adan; Kessler, Benedikt M

    2016-01-01

    Controlling cell proliferation is one of the hallmarks of cancer. A number of critical checkpoints ascertain progression through the different stages of the cell cycle, which can be aborted when perturbed, for instance by errors in DNA replication and repair. These molecular checkpoints are regulated by a number of proteins that need to be present at the right time and quantity. The ubiquitin system has emerged as a central player controlling the fate and function of such molecules such as cyclins, oncogenes and components of the DNA repair machinery. In particular, proteases that cleave ubiquitin chains, referred to as deubiquitylating enzymes (DUBs), have attracted recent attention due to their accessibility to modulation by small molecules. In this review, we describe recent evidence of the critical role of DUBs in aspects of cell cycle checkpoint control, associated DNA repair mechanisms and regulation of transcription, representing pathways altered in cancer. Therefore, DUBs involved in these processes emerge as potentially critical targets for the treatment of not only hematological, but potentially also solid tumors.

  17. Stages of Plasma Cell Neoplasms (Including Multiple Myeloma)

    Science.gov (United States)

    ... Treatment Health Professional Plasma Cell Neoplasms Treatment Research Plasma Cell Neoplasms (Including Multiple Myeloma) Treatment (PDQ®)–Patient Version General Information About Plasma Cell Neoplasms Go to Health Professional Version Key ...

  18. Expression of cell cycle regulator cdk2ap1 suppresses tumor cell phenotype by non-cell autonomous mechanisms

    OpenAIRE

    Zolochevska, Olga; Figueiredo, Marxa L

    2009-01-01

    We evaluated the effect of expressing the cell cycle regulator cdk2ap1 in epithelial or stromal cell compartments to reduce SCC growth in vitro and in vivo. Cell autonomous and/or non-cell autonomous expression of cdk2ap1 reduced tumor growth and invasion and altered cell cycle, adhesion, invasion, angiogenesis, and apoptotic gene expression, as assessed by several in vitro phenotype assays, quantitative real time PCR, and in vivo molecular imaging using a novel three-way xenograft animal mod...

  19. Dynamical modeling of the cell cycle and cell fate emergence in Caulobacter crescentus.

    Directory of Open Access Journals (Sweden)

    César Quiñones-Valles

    Full Text Available The division of Caulobacter crescentus, a model organism for studying cell cycle and differentiation in bacteria, generates two cell types: swarmer and stalked. To complete its cycle, C. crescentus must first differentiate from the swarmer to the stalked phenotype. An important regulator involved in this process is CtrA, which operates in a gene regulatory network and coordinates many of the interactions associated to the generation of cellular asymmetry. Gaining insight into how such a differentiation phenomenon arises and how network components interact to bring about cellular behavior and function demands mathematical models and simulations. In this work, we present a dynamical model based on a generalization of the Boolean abstraction of gene expression for a minimal network controlling the cell cycle and asymmetric cell division in C. crescentus. This network was constructed from data obtained from an exhaustive search in the literature. The results of the simulations based on our model show a cyclic attractor whose configurations can be made to correspond with the current knowledge of the activity of the regulators participating in the gene network during the cell cycle. Additionally, we found two point attractors that can be interpreted in terms of the network configurations directing the two cell types. The entire network is shown to be operating close to the critical regime, which means that it is robust enough to perturbations on dynamics of the network, but adaptable to environmental changes.

  20. Dynamical modeling of the cell cycle and cell fate emergence in Caulobacter crescentus.

    Science.gov (United States)

    Quiñones-Valles, César; Sánchez-Osorio, Ismael; Martínez-Antonio, Agustino

    2014-01-01

    The division of Caulobacter crescentus, a model organism for studying cell cycle and differentiation in bacteria, generates two cell types: swarmer and stalked. To complete its cycle, C. crescentus must first differentiate from the swarmer to the stalked phenotype. An important regulator involved in this process is CtrA, which operates in a gene regulatory network and coordinates many of the interactions associated to the generation of cellular asymmetry. Gaining insight into how such a differentiation phenomenon arises and how network components interact to bring about cellular behavior and function demands mathematical models and simulations. In this work, we present a dynamical model based on a generalization of the Boolean abstraction of gene expression for a minimal network controlling the cell cycle and asymmetric cell division in C. crescentus. This network was constructed from data obtained from an exhaustive search in the literature. The results of the simulations based on our model show a cyclic attractor whose configurations can be made to correspond with the current knowledge of the activity of the regulators participating in the gene network during the cell cycle. Additionally, we found two point attractors that can be interpreted in terms of the network configurations directing the two cell types. The entire network is shown to be operating close to the critical regime, which means that it is robust enough to perturbations on dynamics of the network, but adaptable to environmental changes.

  1. Mast cells as modulators of hair follicle cycling.

    Science.gov (United States)

    Maurer, M; Paus, R; Czarnetzki, B M

    1995-08-01

    While the central role of mast cells (MC) in allergy and inflammation is well-appreciated, much less is known about their physiological functions. The impressive battery of potent growth modulatory MC products, and increasing evidence of MC involvement in hyperproliferative and fibrotic disorders suggest that tissue remodelling may be one of those, namely in the skin. Here, we delineate why this may best be studied by analysing the potential role of MC in hair growth regulation. On the background of numerous, yet widely under-appreciated hints from the older literature, we summarize and discuss our recent observations from the C57BL/6 mouse model for hair research which support the concept that MC are functionally important modulators of hair follicle cycling, specifically during anagen development. This invites to exploit the murine hair cycle as a model for dissecting the physiological growth modulatory functions of MC and encourages the exploration of MC-targeting pharmaceutical strategies for the treatment of hair growth disorders.

  2. Positive Feedback Keeps Duration of Mitosis Temporally Insulated from Upstream Cell-Cycle Events

    OpenAIRE

    Araujo, Ana Rita; Gelens, Lendert; Sheriff, Rahuman; Santos, Silvia D.M.

    2016-01-01

    Cell division is characterized by a sequence of events by which a cell gives rise to two daughter cells. Quan- titative measurements of cell-cycle dynamics in sin- gle cells showed that despite variability in G1-, S-, and G2 phases, duration of mitosis is short and remarkably constant. Surprisingly, there is no corre- lation between cell-cycle length and mitotic duration, suggesting that mitosis is temporally insulated from variability in earlier cell-cycle phases. By combining live cell imag...

  3. End-stage renal disease causes an imbalance between endothelial and smooth muscle progenitor cells

    NARCIS (Netherlands)

    Westerweel, Peter E; Hoefer, Imo E; Blankestijn, Peter J; de Bree, Petra; Groeneveld, Dafna; van Oostrom, Olivia; Braam, Branko; Koomans, Hein A; Verhaar, Marianne C

    2007-01-01

    Patients with end-stage renal disease (ESRD) on hemodialysis have an increased risk of cardiovascular disease (CVD). Circulating endothelial progenitor cells (EPC) contribute to vascular regeneration and repair, thereby protecting against CVD. However, circulating smooth muscle progenitor cells (SPC

  4. Business cycles and the financial performance of fuel cell companies

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, I.; Sadorsky, P. [York Univ., Toronto, ON (Canada). Schulich School of Business

    2005-07-01

    Fuel cells are expected to play a major role in a hydrogen powered world. They will provide power to homes, modes of transportation and appliances. Hydrogen is the most abundant element in nature, but it must be extracted in order to be usable. It can be produced from oil, natural gas and coal or from renewable sources such as biomass, thermal or nuclear reactions. Fuel cells running on hydrogen extracted from non renewable resources have an efficiency of 30 per cent, which is twice as efficient as an internal combustion engine. The greatest barrier to mass commercialization is the cost of making hydrogen-powered auto engines. Also, an infrastructure must be developed to refill hydrogen cars. One solution is to build a hydrogen highway using the existing natural gas grid to produce hydrogen and sell it at existing filling stations. The cost of building 12,000 refueling pumps in urban areas which will provide access to 70 per cent of America's population is estimated at $10 to $15 billion. This paper described the vector autoregression (VAR) model which empirically examines the relationship between financial performance of fuel cell companies and business cycles. It was used to measure how sensitive the financial performance of fuel cell companies are to changes in macroeconomic activity. A four variable VAR model was developed to examine the relationship between stock prices, oil prices and interest rates. It was shown that the stock prices of fuel cell companies are affected by shocks to technology stock prices and oil prices, with the former having a longer lasting impact. These results add to the growing literature that oil price movements are not as important as once thought. 15 refs., 3 tabs., 3 figs.

  5. Cell cycle regulatory factors in juxta-tumoral renal parenchyma.

    Science.gov (United States)

    Petruşcă, Daniela Nicoleta; Petrescu, Amelia; Vrabie, Camelia; Niculescu, L; Jinga, V; Diaconu, Carmen; Braşoveanu, Lorelei

    2005-01-01

    The aim of this study was to evaluate regulatory cell cycle factors in juxta-tumoral renal parenchyma in order to obtain information regarding early primary changes occurred in normal renal cells. Specimens of juxta-tumoral renal parenchyma were harvested from the tumoral kidney in 10 patients with no history of treatment before surgery. The expression of p53, Bcl-2, Rb and PCNA was studied by immunohistochemical methods in paraffin-embedded tissues. The apoptotic status was evaluated by flow-cytometry analysis following propidium iodide incorporation. The p53 protein expression was recognized in most of the cases (80%) with different intensities. High intensity apoptotic process detected in juxta-tumoral parenchyma seemed to be p53 dependent and well correlated with the low Bcl-2 expression. 70% of cases were Rb positive. In this type of tissue Rb has only an anti-proliferative and anti-tumoral role. PCNA was present in half of the cases being low expressed due to the tissue regenerating mechanism. Our data suggest that the high intensity of programmed cell death in this type of tissue is supported by the status of cell regulatory factors that control this process. Previous studies have demonstrated that healthy renal tissue has neither apoptosis nor mitotic activity. Juxta-tumoral renal tissue is also displaying normal morphology and DNA content (diploidy) but the microenvironmental status induced by the tumor presence prompts cells to choose death rather than malignant transformation. Further studies are necessary to emphasize if these results have a clinical relevance for the outcome of therapeutical approaches in renal carcinomas.

  6. Role of Ran GTPase in cell cycle regulation

    Institute of Scientific and Technical Information of China (English)

    JIANG Qing; LU Zhigang; ZHANG Chuanmao

    2004-01-01

    Ran, a member of the Ras GTPase superfamily,is a multifunctional protein and abundant in the nucleus.Many evidences suggest that Ran and its interacting proteins are involved in multiple aspects of the cell cycle regulation.So far it has been conformed that Ran and its interacting proteins control the nucleocytoplasmic transport, the nuclear envelope (NE) assembly, the DNA replication and the spindle assembly, although many details of the mechanisms are waiting for elucidation. It has also been implicated that Ran and its interacting proteins are involved in regulating the integrity of the nuclear structure, the mRNA transcription and splicing, and the RNA transport from the nucleus to the cytoplasm. In this review we mainly discuss the mechanisms by which Ran and its interacting proteins regulate NE assembly, DNA replication and spindle assembly.

  7. Arsenic Trioxide Inhibits Proliferation in K562 Cells by Changing Cell Cycle and Survivin Expression

    Institute of Scientific and Technical Information of China (English)

    伍晓菲; 陈智超; 刘仲萍; 周浩; 游泳; 黎纬明; 邹萍

    2004-01-01

    To study the mechanisms involved in the inhibition of chronic myeloid leukemic cells (K562) proliferation induced by arsenic trioxide (As2O3) and to explore the potential role of Survivin, an inhibitor of apoptosis protein, in the regulation of As2O3 induced cell apoptosis, K562 cells were cultured with As2O3 of different concentrations. Cells were collected for proliferation analysis by MTT assay. Cell cycle distribution and cell apoptosis were analyzed by flow cytometry.Expression of Survivin protein and mRNA were detected by flow cytometry and RT-PCR, respectively. Our results showed that As2O3 (2-10 μmol/L) inhibited K562 cells growth effectively, but it did not induce cells apoptosis significantly. The percentage of K562 cells at G2/M phase increased in proportion to As2O3 concentrations, and the expression of Survivin mRNA and content of Survivin protein was up-regulated accordingly. It is concluded that As2 O3 inhibited K562 cells growth by inducing cell cycle arrest mainly at G2/M phase. Over-expression of Survivin gene and protein might be one of the possible mechanisms contributing to K562 cells' resistance to As2O3-induced apoptosis.

  8. Impaired germ cell development due to compromised cell cycle progression in Skp2-deficient mice

    Directory of Open Access Journals (Sweden)

    Nakayama Keiko

    2006-04-01

    Full Text Available Abstract Background The gonads are responsible for the production of germ cells through both mitosis and meiosis. Skp2 is the receptor subunit of an SCF-type ubiquitin ligase and is a major regulator of the progression of cells into S phase of the cell cycle, which it promotes by mediating the ubiquitin-dependent degradation of p27, an inhibitor of cell proliferation. However, the role of the Skp2-p27 pathway in germ cell development remains elusive. Results We now show that disruption of Skp2 in mice results in a marked impairment in the fertility of males, with the phenotypes resembling Sertoli cell-only syndrome in men. Testes of Skp2-/- mice manifested pronounced germ cell hypoplasia accompanied by massive apoptosis in spermatogenic cells. Flow cytometry revealed an increased prevalence of polyploidy in spermatozoa, suggesting that the aneuploidy of these cells is responsible for the induction of apoptosis. Disruption of the p27 gene of Skp2-/- mice restored germ cell development, indicating that the testicular hypoplasia of Skp2-/- animals is attributable to the antiproliferative effect of p27 accumulation. Conclusion Our results thus suggest that compromised cell cycle progression caused by the accumulation of p27 results in aneuploidy and the induction of apoptosis in gonadal cells of Skp2-/- mice. The consequent reduction in the number of mature gametes accounts for the decreased fertility of these animals. These findings reinforce the importance of the Skp2-p27 pathway in cell cycle regulation and in germ cell development.

  9. Global analysis of cell cycle gene expression of the legume symbiont Sinorhizobium meliloti.

    Science.gov (United States)

    De Nisco, Nicole J; Abo, Ryan P; Wu, C Max; Penterman, Jon; Walker, Graham C

    2014-03-04

    In α-proteobacteria, strict regulation of cell cycle progression is necessary for the specific cellular differentiation required for adaptation to diverse environmental niches. The symbiotic lifestyle of Sinorhizobium meliloti requires a drastic cellular differentiation that includes genome amplification. To achieve polyploidy, the S. meliloti cell cycle program must be altered to uncouple DNA replication from cell division. In the α-proteobacterium Caulobacter crescentus, cell cycle-regulated transcription plays an important role in the control of cell cycle progression but this has not been demonstrated in other α-proteobacteria. Here we describe a robust method for synchronizing cell growth that enabled global analysis of S. meliloti cell cycle-regulated gene expression. This analysis identified 462 genes with cell cycle-regulated transcripts, including several key cell cycle regulators, and genes involved in motility, attachment, and cell division. Only 28% of the 462 S. meliloti cell cycle-regulated genes were also transcriptionally cell cycle-regulated in C. crescentus. Furthermore, CtrA- and DnaA-binding motif analysis revealed little overlap between the cell cycle-dependent regulons of CtrA and DnaA in S. meliloti and C. crescentus. The predicted S. meliloti cell cycle regulon of CtrA, but not that of DnaA, was strongly conserved in more closely related α-proteobacteria with similar ecological niches as S. meliloti, suggesting that the CtrA cell cycle regulatory network may control functions of central importance to the specific lifestyles of α-proteobacteria.

  10. Propionibacterium acnes inhibits FOXM1 and induces cell cycle alterations in human primary prostate cells

    DEFF Research Database (Denmark)

    Sayanjali, Behnam; Christensen, Gitte J M; Al-Zeer, Munir A;

    2016-01-01

    Propionibacterium acnes has been detected in diseased human prostate tissue, and cell culture experiments suggest that the bacterium can establish a low-grade inflammation. Here, we investigated its impact on human primary prostate epithelial cells. Microarray analysis confirmed the inflammation......-inducing capability of P. acnes but also showed deregulation of genes involved in the cell cycle. qPCR experiments showed that viable P. acnes downregulates a master regulator of cell cycle progression, FOXM1. Flow cytometry experiments revealed that P. acnes increases the number of cells in S-phase. We tested...... the hypothesis that a P. acnes-produced berninamycin-like thiopeptide is responsible for this effect, since it is related to the FOXM1 inhibitor siomycin. The thiopeptide biosynthesis gene cluster was strongly expressed; it is present in subtype IB of P. acnes, but absent from type IA, which is most abundant...

  11. Rhythmic profiles of cell cycle and circadian clock gene transcripts in mice: a possible association between two periodic systems.

    Science.gov (United States)

    Weigl, Yuval; Ashkenazi, Israel E; Peleg, Leah

    2013-06-15

    The circadian system shapes the rhythms of most biological functions. The regulation of the cell cycle by a circadian clock was suggested to operate via stages S, G2 and G2/M. This study investigated a possible time link at stages G1 and G1/S as well. The daily expression profiles of cell cycle markers (Ccnd1, Ccne1 and Pcna) and circadian clock genes (Per2 and Clock) were monitored in liver and esophagus (low and high proliferation index, respectively) of BALB/c mice. Locomotor activity displayed a 24 h rhythm, establishing the circadian organization of the suprachiasmatic nucleus. In the liver, the mRNA level of Per2 and Clock fitted the circadian rhythm with a 7.5 h shift. This temporal pattern suggests that the liver harbors a functional circadian clock. The rhythm of the analyzed cell cycle genes, however, was of low significance fitness and showed an opposite peak time between Pcna and Clock. These results indicate a weak regulatory role of the circadian clock. In the esophagus, the rhythms of Clock and Per2 mRNA had a similar peak time and non-circadian periods. These results suggest either that the esophagus does not harbor a functional circadian apparatus or that the phenotypes stem from differences in phase and amplitude of the rhythms of its various cell types. The similarity in the rhythm parameters of Clock, Ccne1 and Pcna transcripts questions the control of the circadian clock on the cell cycle along the G1 and G1/S stages. Yet the G1/S transition may play a role in modulating the local clock of proliferating tissues.

  12. Does MW Radiation Affect Gene Expression, Apoptotic Level, and Cell Cycle Progression of Human SH-SY5Y Neuroblastoma Cells?

    Science.gov (United States)

    Kayhan, Handan; Esmekaya, Meric Arda; Saglam, Atiye Seda Yar; Tuysuz, Mehmed Zahid; Canseven, Ayşe Gulnihal; Yagci, Abdullah Munci; Seyhan, Nesrin

    2016-06-01

    Neuroblastoma (NB) is a cancer that occurs in sympathetic nervous system arising from neuroblasts and nerve tissue of the adrenal gland, neck, chest, or spinal cord. It is an embryonal malignancy and affects infants and children. In this study, we investigated the effects of microwave (MW) radiation on apoptotic activity, cell viability, and cell cycle progression in human SH-SY5Y NB cells which can give information about MW radiation effects on neural cells covering the period from the embryonic stages to infants. SH-SY5Y NB cells were exposed to 2.1 GHz W-CDMA modulated MW radiation for 24 h at a specific absorption rate of 0.491 W/kg. Control samples were in the same conditions with MW-exposed samples but they were not exposed to MW radiation. The apoptotic activity of cells was measured by Annexin-V-FITC and propidium iodide staining. Moreover, mRNA levels of proliferative and cell cycle proteins were determined by real-time RT-PCR. The change in cell cycle progression was observed by using CycleTest-Plus DNA reagent. No significant change was observed in apoptotic activity of MW-exposed cells compared to control cells. The mRNA levels of c-myc and cyclin D1 were significantly reduced in MW group (p CDMA modulated MW radiation did not cause apoptotic cell death but changed cell cycle progression.

  13. Life cycle assessment of fuel cell vehicles: Dealing with uncertainties

    Science.gov (United States)

    Contadini, Jose Fernando

    Life cycle assessment (LCA), or "well to wheels" in transportation terms, involves some subjectivity and uncertainty, especially with new technologies and future scenarios. To analyze lifecycle impacts of future fuel cell vehicles and fuels, I developed the Fuel Upstream Energy and Emission Model (FUEEM). The FUEEM project pioneered two specific new ways to incorporate and propagate uncertainty within an LCA analysis. First, the model uses probabilistic curves generated by experts as inputs and then employs Monte Carlo simulation techniques to propagate these uncertainties throughout the full chain of fuel production and use. Second, the FUEEM process explicitly involves the interested parties in the entire analysis process, not only in the critical final review phase. To demonstrate the FUEEM process, an analysis has been made for the use of three different fuel cell vehicle technologies (direct hydrogen, indirect methanol, and indirect hydrocarbon) in 2010 within the South Coast Air Basin (SCAB) of California (Los Angeles). The analysis covered topics such as the requirement of non-renewable energy sources, emissions of CO2 and other greenhouse gases, and emissions of several criteria pollutants generated within SCAB and within other regions. The results obtained from this example show that the hydrogen option has the potential to have the most efficient energy life cycle for the SCAB, followed by the methanol and finally by the Fisher-Tropsch naphtha option. A similar pattern is observed for the greenhouse gas emissions. The results showing criteria pollutants emitted within SCAB highlight the importance of having a flexible model that is responsive to local considerations. This dissertation demonstrates that explicit recognition and quantitative analysis of the inherent uncertainty in the LCA process generates richer information, explains many of the discrepancies between results of previous studies, and enhances the robustness and credibility of LCA analyses.

  14. Effects of Genistein on Proliferation and Cell Cycle of Salivary Adenoid Cystic Carcinoma Cells

    Institute of Scientific and Technical Information of China (English)

    MA Jie; WANG Jie; ZHONG Ming; WANG Zhao-yuan

    2007-01-01

    Objective: To investigate the growth inhibiting effect of tyrosine protein kinase inhibitor, genistein, on human salivary adenoid cystic carcinoma SACC-83 cell line in vitro, and its effects on the expression of CyclinB1 protein and cell cycle. Methods: Effects of genistein on the growth of SACC-83 cells in vitro were measured with MTT assay. Cell cycle was detected with flow cytometry. The expressions of CyclinB1 and Cdk1 proteins were measured with Western blot method, and the results of protein expression were quantitatively analyzed by FluorChem V2.0 software. The results were statistically analyzed by SPSS11.5 software. Results: Genistein inhibited the cell proliferation in a dose-dependant and time-dependant manner. The genistein-treated SACC-83 cells were arrested in the G2/M phase and had lower contents of CyclinB1 and Cdk1 proteins compared with the control group. Conclusion: The growth inhibiting effect of genistein on SACC-83 cells may be associated with the regulations of genistein on the CyclinB1 and Cdk1 protein expressions and the cell cycle.

  15. Effect of sesamin on apoptosis and cell cycle arrest in human breast cancer mcf-7 cells.

    Science.gov (United States)

    Siao, An-Ci; Hou, Chien-Wei; Kao, Yung-Hsi; Jeng, Kee-Ching

    2015-01-01

    Dietary prevention has been known to reduce breast cancer risk. Sesamin is one of the major components in sesame seeds and has been widely studied and proven to have anti-proliferation and anti-angiogenic effects on cancer cells. In this study, the influence of sesamin was tested in the human breast cancer MCF-7 cell line for cell viability (MTT assay) and cell cycling (flow cytometry). Results showed that sesamin dose-dependently (1, 10 and 50 μM) reduced the cell viability and increased LDH release and apoptosis (TUNEL assay). In addition, there was a significant increase of sub-G1 phase arrest in the cell cycle after sesamin treatment. Furthermore, sesamin increased the expression of apoptotic markers of Bax, caspase-3, and cell cycle control proteins, p53 and checkpoint kinase 2. Taken together, these results suggested that sesamin might be used as a dietary supplement for prevention of breast cancer by modulating apoptotic signal pathways and inhibiting tumor cell growth.

  16. Simvastatin induces cell cycle arrest and inhibits proliferation of bladder cancer cells via PPARγ signalling pathway

    Science.gov (United States)

    Wang, Gang; Cao, Rui; Wang, Yongzhi; Qian, Guofeng; Dan, Han C.; Jiang, Wei; Ju, Lingao; Wu, Min; Xiao, Yu; Wang, Xinghuan

    2016-01-01

    Simvastatin is currently one of the most common drugs for old patients with hyperlipidemia, hypercholesterolemia and atherosclerotic diseases by reducing cholesterol level and anti-lipid properties. Importantly, simvastatin has also been reported to have anti-tumor effect, but the underlying mechanism is largely unknown. We collected several human bladder samples and performed microarray. Data analysis suggested bladder cancer (BCa) was significantly associated with fatty acid/lipid metabolism via PPAR signalling pathway. We observed simvastatin did not trigger BCa cell apoptosis, but reduced cell proliferation in a dose- and time-dependent manner, accompanied by PPARγ-activation. Moreover, flow cytometry analysis indicated that simvastatin induced cell cycle arrest at G0/G1 phase, suggested by downregulation of CDK4/6 and Cyclin D1. Furthermore, simvastatin suppressed BCa cell metastasis by inhibiting EMT and affecting AKT/GSK3β. More importantly, we found that the cell cycle arrest at G0/G1 phase and the alterations of CDK4/6 and Cyclin D1 triggered by simvastatin could be recovered by PPARγ-antagonist (GW9662), whereas the treatment of PPARα-antagonist (GW6471) shown no significant effects on the BCa cells. Taken together, our study for the first time revealed that simvastatin inhibited bladder cancer cell proliferation and induced cell cycle arrest at G1/G0 phase via PPARγ signalling pathway. PMID:27779188

  17. Glucose-ABL1-TOR Signaling Modulates Cell Cycle Tuning to Control Terminal Appressorial Cell Differentiation

    Science.gov (United States)

    2017-01-01

    The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon-responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round of mitosis followed by autophagic cell death of the conidium. In contrast, Δabl1 mutant strains undergo multiple rounds of accelerated mitosis in elongated germ tubes, produce few appressoria, and are abolished for autophagy. Treating WT spores with glucose or 2-deoxyglucose phenocopied Δabl1. Inactivating TOR in Δabl1 mutants or glucose-treated WT strains restored appressorium formation by promoting mitotic arrest at G1/G0 via an appressorium- and autophagy-inducing cell cycle delay at G2/M. Collectively, this work uncovers a novel glucose-ABL1-TOR signaling axis and shows it engages two metabolic checkpoints in order to modulate cell cycle tuning and mediate terminal appressorial cell differentiation. We thus provide new molecular insights into TOR regulation and cell development in response to glucose. PMID:28072818

  18. Insights to the effects of free cells on community structure of attached cells and chalcopyrite bioleaching during different stages.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2016-01-01

    The effects of free cells on community structure of attached cells and chalcopyrite bioleaching by Acidithiobacillus sp. during different stages were investigated. The attached cells of Acidithiobacillus thiooxidans owned the community advantage from 14thd to the end of bioprocess in the normal system. The community structure of attached cells was greatly influenced in the free cells-deficient systems. Compared to A. thiooxidans, the attached cells community of Acidithiobacillus ferrooxidans had a higher dependence on its free cells. Meanwhile, the analysis of key biochemical parameters revealed that the effects of free cells on chalcopyrite bioleaching in different stages were diverse, ranging from 32.8% to 64.3%. The bioleaching contribution of free cells of A. ferrooxidans in the stationary stage (8-14thd) was higher than those of A. thiooxidans, while the situation was gradually reversed in the jarosite passivation inhibited stage (26-40thd). These results may be useful in guiding chalcopyrite bioleaching.

  19. Differences in CART expression and cell cycle behavior discriminate sympathetic neuroblast from chromaffin cell lineages in mouse sympathoadrenal cells.

    Science.gov (United States)

    Chan, Wing Hei; Gonsalvez, David G; Young, Heather M; Southard-Smith, E Michelle; Cane, Kylie N; Anderson, Colin R

    2016-02-01

    Adrenal medullary chromaffin cells and peripheral sympathetic neurons originate from a common sympathoadrenal (SA) progenitor cell. The timing and phenotypic changes that mark this lineage diversification are not fully understood. The present study investigated the expression patterns of phenotypic markers, and cell cycle dynamics, in the adrenal medulla and the neighboring suprarenal ganglion of embryonic mice. The noradrenergic marker, tyrosine hydroxylase (TH), was detected in both presumptive adrenal medulla and sympathetic ganglion cells, but with significantly stronger immunostaining in the former. There was intense cocaine and amphetamine-regulated transcript (CART) peptide immunostaining in most neuroblasts, whereas very few adrenal chromaffin cells showed detectable CART immunostaining. This phenotypic segregation appeared as early as E12.5, before anatomical segregation of the two cell types. Cell cycle dynamics were also examined. Initially, 88% of Sox10 positive (+) neural crest progenitors were proliferating at E10.5. Many SA progenitor cells withdrew from the cell cycle at E11.5 as they started to express TH. Whereas 70% of neuroblasts (TH+/CART+ cells) were back in the cell cycle at E12.5, only around 20% of chromaffin (CART negative) cells were in the cell cycle at E12.5 and subsequent days. Thus, chromaffin cell and neuroblast lineages showed differences in proliferative behavior from their earliest appearance. We conclude that the intensity of TH immunostaining and the expression of CART permit early discrimination of chromaffin cells and sympathetic neuroblasts, and that developing chromaffin cells exhibit significantly lower proliferative activity relative to sympathetic neuroblasts.

  20. Quantitative proteomic analysis of cell cycle of the dinoflagellate Prorocentrum donghaiense (Dinophyceae.

    Directory of Open Access Journals (Sweden)

    Da-Zhi Wang

    Full Text Available Dinoflagellates are the major causative agents of harmful algal blooms in the coastal zone, which has resulted in adverse effects on the marine ecosystem and public health, and has become a global concern. Knowledge of cell cycle regulation in proliferating cells is essential for understanding bloom dynamics, and so this study compared the protein profiles of Prorocentrum donghaiense at different cell cycle phases and identified differentially expressed proteins using 2-D fluorescence difference gel electrophoresis combined with MALDI-TOF-TOF mass spectrometry. The results showed that the synchronized cells of P. donghaiense completed a cell cycle within 24 hours and cell division was phased with the diurnal cycle. Comparison of the protein profiles at four cell cycle phases (G1, S, early and late G2/M showed that 53 protein spots altered significantly in abundance. Among them, 41 were identified to be involved in a variety of biological processes, e.g. cell cycle and division, RNA metabolism, protein and amino acid metabolism, energy and carbon metabolism, oxidation-reduction processes, and ABC transport. The periodic expression of these proteins was critical to maintain the proper order and function of the cell cycle. This study, to our knowledge, for the first time revealed the major biological processes occurring at different cell cycle phases which provided new insights into the mechanisms regulating the cell cycle and growth of dinoflagellates.

  1. Effect of cell cycle inhibitor p19ARF on senescence of human diploid cell

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    To investigate the effect of cell cycle inhibitor p19ARF on replicative senescence of human diploid cell, recombinant p19ARF eukaryotic expression vector was constructed and p19ARF gene was transfected into human diploid fibroblasts (WI-38 cells) by liposome-mediated transfection for overexpression. Then, the effects of p19ARF on replicative senescence of WI-38 cells were observed. The results re- vealed that, compared with control cells, the WI-38 cells in which p19ARF gene was introduced showed significant up-regulation of p53 and p21 expression level, decrease of cell generation by 10 12 generations, decline of cell growth rate with cell cycle being arrested at G1 phase, increase of positive rate of senescent marker SA-β-gal staining, and decrease of mitochondrial membrane potential. The morphology of the transfected fibroblasts presented the characteristics changes similar to senescent cells. These results indicated that high expression of p19ARF may promote the senescent process of human diploid cells.

  2. Abnormal mitosis triggers p53-dependent cell cycle arrest in human tetraploid cells.

    Science.gov (United States)

    Kuffer, Christian; Kuznetsova, Anastasia Yurievna; Storchová, Zuzana

    2013-08-01

    Erroneously arising tetraploid mammalian cells are chromosomally instable and may facilitate cell transformation. An increasing body of evidence shows that the propagation of mammalian tetraploid cells is limited by a p53-dependent arrest. The trigger of this arrest has not been identified so far. Here we show by live cell imaging of tetraploid cells generated by an induced cytokinesis failure that most tetraploids arrest and die in a p53-dependent manner after the first tetraploid mitosis. Furthermore, we found that the main trigger is a mitotic defect, in particular, chromosome missegregation during bipolar mitosis or spindle multipolarity. Both a transient multipolar spindle followed by efficient clustering in anaphase as well as a multipolar spindle followed by multipolar mitosis inhibited subsequent proliferation to a similar degree. We found that the tetraploid cells did not accumulate double-strand breaks that could cause the cell cycle arrest after tetraploid mitosis. In contrast, tetraploid cells showed increased levels of oxidative DNA damage coinciding with the p53 activation. To further elucidate the pathways involved in the proliferation control of tetraploid cells, we knocked down specific kinases that had been previously linked to the cell cycle arrest and p53 phosphorylation. Our results suggest that the checkpoint kinase ATM phosphorylates p53 in tetraploid cells after abnormal mitosis and thus contributes to proliferation control of human aberrantly arising tetraploids.

  3. Chloroplast Dysfunction Causes Multiple Defects in Cell Cycle Progression in the Arabidopsis crumpled leaf Mutant

    KAUST Repository

    Hudik, Elodie

    2014-07-18

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  4. Chloroplast dysfunction causes multiple defects in cell cycle progression in the Arabidopsis crumpled leaf mutant.

    Science.gov (United States)

    Hudik, Elodie; Yoshioka, Yasushi; Domenichini, Séverine; Bourge, Mickaël; Soubigout-Taconnat, Ludivine; Mazubert, Christelle; Yi, Dalong; Bujaldon, Sandrine; Hayashi, Hiroyuki; De Veylder, Lieven; Bergounioux, Catherine; Benhamed, Moussa; Raynaud, Cécile

    2014-09-01

    The majority of research on cell cycle regulation is focused on the nuclear events that govern the replication and segregation of the genome between the two daughter cells. However, eukaryotic cells contain several compartmentalized organelles with specialized functions, and coordination among these organelles is required for proper cell cycle progression, as evidenced by the isolation of several mutants in which both organelle function and overall plant development were affected. To investigate how chloroplast dysfunction affects the cell cycle, we analyzed the crumpled leaf (crl) mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for a chloroplastic protein and displays particularly severe developmental defects. In the crl mutant, we reveal that cell cycle regulation is altered drastically and that meristematic cells prematurely enter differentiation, leading to reduced plant stature and early endoreduplication in the leaves. This response is due to the repression of several key cell cycle regulators as well as constitutive activation of stress-response genes, among them the cell cycle inhibitor SIAMESE-RELATED5. One unique feature of the crl mutant is that it produces aplastidic cells in several organs, including the root tip. By investigating the consequence of the absence of plastids on cell cycle progression, we showed that nuclear DNA replication occurs in aplastidic cells in the root tip, which opens future research prospects regarding the dialogue between plastids and the nucleus during cell cycle regulation in higher plants.

  5. [Ligandin localization in the gonadal cells of rats at various stages of ontogeny].

    Science.gov (United States)

    Bannikov, G A; Chipysheva, T A

    1979-01-01

    Ligandin, a protein binding some carcinogens, steroids and other substances in the rat liver, has been found by means of indirect immunofluorescence in the gonad cells of different types: embryonic and mature Leidig cells in testes, ovarian thecal cells at the maturation stages (theca interna, atretic follicles and interstitial cells) and luteal cells of corpus luteum at pregnancy. Ligandin is found, thus, in cells which belong to various lines of cell differentiation. The functional role of ligandin is discussed.

  6. A hybrid model of mammalian cell cycle regulation.

    Directory of Open Access Journals (Sweden)

    Rajat Singhania

    Full Text Available The timing of DNA synthesis, mitosis and cell division is regulated by a complex network of biochemical reactions that control the activities of a family of cyclin-dependent kinases. The temporal dynamics of this reaction network is typically modeled by nonlinear differential equations describing the rates of the component reactions. This approach provides exquisite details about molecular regulatory processes but is hampered by the need to estimate realistic values for the many kinetic constants that determine the reaction rates. It is difficult to estimate these kinetic constants from available experimental data. To avoid this problem, modelers often resort to 'qualitative' modeling strategies, such as Boolean switching networks, but these models describe only the coarsest features of cell cycle regulation. In this paper we describe a hybrid approach that combines the best features of continuous differential equations and discrete Boolean networks. Cyclin abundances are tracked by piecewise linear differential equations for cyclin synthesis and degradation. Cyclin synthesis is regulated by transcription factors whose activities are represented by discrete variables (0 or 1 and likewise for the activities of the ubiquitin-ligating enzyme complexes that govern cyclin degradation. The discrete variables change according to a predetermined sequence, with the times between transitions determined in part by cyclin accumulation and degradation and as well by exponentially distributed random variables. The model is evaluated in terms of flow cytometry measurements of cyclin proteins in asynchronous populations of human cell lines. The few kinetic constants in the model are easily estimated from the experimental data. Using this hybrid approach, modelers can quickly create quantitatively accurate, computational models of protein regulatory networks in cells.

  7. The Trypanosoma cruzi nucleic acid binding protein Tc38 presents changes in the intramitochondrial distribution during the cell cycle

    Directory of Open Access Journals (Sweden)

    Nardelli Sheila C

    2009-02-01

    Full Text Available Abstract Background Tc38 of Trypanosoma cruzi has been isolated as a single stranded DNA binding protein with high specificity for the poly [dT-dG] sequence. It is present only in Kinetoplastidae protozoa and its sequence lacks homology to known functional domains. Tc38 orthologues present in Trypanosoma brucei and Leishmania were proposed to participate in quite different cellular processes. To further understand the function of this protein in Trypanosoma cruzi, we examined its in vitro binding to biologically relevant [dT-dG] enriched sequences, its expression and subcellular localization during the cell cycle and through the parasite life stages. Results By using specific antibodies, we found that Tc38 protein from epimastigote extracts participates in complexes with the poly [dT-dG] probe as well as with the universal minicircle sequence (UMS, a related repeated sequence found in maxicircle DNA, and the telomeric repeat. However, we found that Tc38 predominantly localizes into the mitochondrion. Though Tc38 is constitutively expressed through non-replicating and replicating life stages of T. cruzi, its subcellular localization in the unique parasite mitochondrion changes according to the cell cycle stage. In epimastigotes, Tc38 is found only in association with kDNA in G1 phase. From the S to G2 phase the protein localizes in two defined and connected spots flanking the kDNA. These spots disappear in late G2 turning into a diffuse dotted signal which extends beyond the kinetoplast. This later pattern is more evident in mitosis and cytokinesis. Finally, late in cytokinesis Tc38 reacquires its association with the kinetoplast. In non-replicating parasite stages such as trypomastigotes, the protein is found only surrounding the entire kinetoplast structure. Conclusions The dynamics of Tc38 subcellular localization observed during the cell cycle and life stages support a major role for Tc38 related to kDNA replication and maintenance.

  8. Effect of Juglone in qinglongyi on cell cycle status and apoptosis in A-549 cells

    Institute of Scientific and Technical Information of China (English)

    ZOU Xiang; KONG Ling-sheng; JI Yu-bin

    2008-01-01

    Objective To explore the inhibition of juglone in Qinglongyi on A-549 cells in vitro. Methods MTT assay was used. Laser confocal scanning microscope was used to observe apoptotic morphology.Changes of cell cycle are studied by flow cytometry analysis. Results MTT assay showed that juglone had a marked growth inhibition in A-549 cells and the IC50 is respectively 3.4×10-5 mol·L-1, 1.8×10-5 mol·L-1 and 2.6×10-6 mol·L-1 after treatment for 24, 48 and 72 h by juglone. Through Laser confocal scanning microscope, we can see that juglone can induce the apoptosis. Cell cycle changes are analyzed by flow cytometry with cells at G1 phase significantly less than those of control and ceils at G2 phase significantly more than those of control. Conclusions It suggests that juglone could apoptosis of A-549 cells with the cell cycle arrest on G2 phase in distinct dose-dependent manner.

  9. Heterochronic misexpression of Ascl1 in the Atoh7 retinal cell lineage blocks cell cycle exit.

    Science.gov (United States)

    Hufnagel, Robert B; Riesenberg, Amy N; Quinn, Malgorzata; Brzezinski, Joseph A; Glaser, Tom; Brown, Nadean L

    2013-05-01

    Retinal neurons and glia arise from a common progenitor pool in a temporal order, with retinal ganglion cells (RGCs) appearing first, and Müller glia last. The transcription factors Atoh7/Math5 and Ascl1/Mash1 represent divergent bHLH clades, and exhibit distinct spatial and temporal retinal expression patterns, with little overlap during early development. Here, we tested the ability of Ascl1 to change the fate of cells in the Atoh7 lineage when misexpressed from the Atoh7 locus, using an Ascl1-IRES-DsRed2 knock-in allele. In Atoh7(Ascl1KI/+) and Atoh7(Ascl1KI/Ascl1KI) embryos, ectopic Ascl1 delayed cell cycle exit and differentiation, even in cells coexpressing Atoh7. The heterozygous retinas recovered, and eventually produced a normal complement of RGCs, while homozygous substitution of Ascl1 for Atoh7 did not promote postnatal retinal fates precociously, nor rescue Atoh7 mutant phenotypes. However, our analyses revealed two unexpected findings. First, ectopic Ascl1 disrupted cell cycle progression within the marked Atoh7 lineage, but also nonautonomously in other retinal cells. Second, the size of the Atoh7 retinal lineage was unaffected, supporting the idea of a compensatory shift of the non-proliferative cohort to maintain lineage size. Overall, we conclude that Ascl1 acts dominantly to block cell cycle exit, but is incapable of redirecting the fates of early RPCs.

  10. Effects of tachyplesin on the regulation of cell cycle in human hepatocarcinoma SMMC-7721 cells

    Institute of Scientific and Technical Information of China (English)

    Qi-Fu Li; Gao-Liang Ouyang; Xuan-Xian Peng; Shui-Gen Hong

    2003-01-01

    AIM: To investigate the effects of tachyplesin on the cell cycle regulation in human hepatcarcinoma cells.METHODS: Effects of tachyplesin on the cell cycle in human hepatocarcinoma SMMC-7721 cells were assayed with flow cytometry. The protein levels of p53, p16, cyclin D1 and CDK4 were assayed by immunocytochemistry. The mRNA levels of p21WAF1/CIP1 and c-myc genes were examined with in situ hybridization assay.RESULTS: After tachyplesin treatment, the cell cycle arrested at G0/G1 phase, the protein levels of mutant p53, cyclin D1 and CDK4 and the mRNA level of c-myc gene were decreased, whereas the levels of p16 protein and p21wWF1/CIP1 mRNA increased.CONCLUSION: Tachyplesin might arrest the cell at G0/G1 phase by upregulating the levels of p16 protein and p21WAF1/CIP1 mRNA and downregulating the levels of mutant p53, cyclin D1 and CDK4 proteins and c-myc mRNA, and induce the differentiation of human hepatocacinoma cells.

  11. Propionibacterium acnes inhibits FOXM1 and induces cell cycle alterations in human primary prostate cells.

    Science.gov (United States)

    Sayanjali, Behnam; Christensen, Gitte J M; Al-Zeer, Munir A; Mollenkopf, Hans-Joachim; Meyer, Thomas F; Brüggemann, Holger

    2016-11-01

    Propionibacterium acnes has been detected in diseased human prostate tissue, and cell culture experiments suggest that the bacterium can establish a low-grade inflammation. Here, we investigated its impact on human primary prostate epithelial cells. Microarray analysis confirmed the inflammation-inducing capability of P. acnes but also showed deregulation of genes involved in the cell cycle. qPCR experiments showed that viable P. acnes downregulates a master regulator of cell cycle progression, FOXM1. Flow cytometry experiments revealed that P. acnes increases the number of cells in S-phase. We tested the hypothesis that a P. acnes-produced berninamycin-like thiopeptide is responsible for this effect, since it is related to the FOXM1 inhibitor siomycin. The thiopeptide biosynthesis gene cluster was strongly expressed; it is present in subtype IB of P. acnes, but absent from type IA, which is most abundant on human skin. A knock-out mutant lacking the gene encoding the berninamycin-like peptide precursor was unable to downregulate FOXM1 and to halt the cell cycle. Our study reveals a novel host cell-interacting activity of P. acnes.

  12. Lipid and fatty acid content in wild white seabream (Diplodus sargus) broodstock at different stages of the reproductive cycle.

    Science.gov (United States)

    Pérez, M J; Rodríguez, C; Cejas, J R; Martín, M V; Jerez, S; Lorenzo, A

    2007-02-01

    The lipid and fatty acid content of the gonads, liver and muscle of wild white seabream males and females was studied at different stages of the reproductive cycle. Samples were taken from mature white seabream at pre-spawning (November), mid-spawning (March) and post-spawning (June) stages. The results showed that lipid accumulates in gonads and muscle from November to March. The gonadosomatic index (GSI) was also increased during this period. Male gonads showed a greater increase in polar lipid (PL) than neutral (NL), while female gonads displayed the reverse. The increase in both neutral and polar lipid was higher in the muscle of males than in females. In the same period, male livers showed no changes either in lipid content or the hepatosomatic index (HSI), while female livers registered an increase in both lipid content and HSI. Between March and June, in both males and females, total, neutral and polar lipid decreased sharply in the gonads and muscle. Muscular lipid content reduction was more pronounced in males than females. On the other hand, the lipid content of the liver in males and females remained relatively constant. In general terms, the amounts of major fatty acids (16:0, 18:1n-9, 20:5n-3 and 22:6n-3) in gonadal and muscular polar and neutral lipid in both males and females increased from November to March and declined thereafter. Variations of the liver fatty acid content were less extreme. In the period from mid-spawning to post-spawning, the presence of 20:4n-6 in polar and neutral lipid increased to a notable extent in all organs studied.

  13. Cell Attachment of Periodontal Ligament Cells on Commercially Pure Titanium at the Early Stage

    Institute of Scientific and Technical Information of China (English)

    周彬; 曹颖光; 吴丽娟; 袁艳祥; 曾引萍

    2004-01-01

    Summary: In order to study the character of periodontal ligament cells (PDLCs) attaching on commercially pure titanium (cpTi) by morphology and metrology on the early stage (24 h), 1×105/ml PDLCs in 2 ml culture medium were seeded on cpTi discs fixed in 24-well culture plates. Morphology of cell attachment was observed by contrast phase microscope, scanning electron microscope (SEM) and fluroscence microscopy. Cell adhesion was analyzed by MTT at 0.5, 1, 2, 4 h respectively. PDLCs could attach and spread on cpTi discs. SEM showed that PDLCs had pseudopod-like protuberance. PDLCs showed different attaching phases and reached saturation in cell number at 2 h. It was concluded that PDLCs had good biocompatibility with cpTi, and showed a regular and dynamic pattern in the process of attaching to cpTi.

  14. Chromatin dynamics during cell cycle mediate conversion of DNA damage into chromatid breaks and affect formation of chromosomal aberrations: Biological and clinical significance

    Energy Technology Data Exchange (ETDEWEB)

    Terzoudi, Georgia I.; Hatzi, Vasiliki I. [Institute of Radioisotopes and Radiodiagnostic Products, National Centre for Scientific Research ' Demokritos' , 15310 Ag. Paraskevi Attikis, Athens (Greece); Donta-Bakoyianni, Catherine [Oral Diagnosis and Radiology, University of Athens Dental School, Athens (Greece); Pantelias, Gabriel E., E-mail: gabriel@ipta.demokritos.gr [Institute of Radioisotopes and Radiodiagnostic Products, National Centre for Scientific Research ' Demokritos' , 15310 Ag. Paraskevi Attikis, Athens (Greece)

    2011-06-03

    The formation of diverse chromosomal aberrations following irradiation and the variability in radiosensitivity at different cell-cycle stages remain a long standing controversy, probably because most of the studies have focused on elucidating the enzymatic mechanisms involved using simple DNA substrates. Yet, recognition, processing and repair of DNA damage occur within the nucleoprotein complex of chromatin which is dynamic in nature, capable of rapid unfolding, disassembling, assembling and refolding. The present work reviews experimental work designed to investigate the impact of chromatin dynamics and chromosome conformation changes during cell-cycle in the formation of chromosomal aberrations. Using conventional cytogenetics and premature chromosome condensation to visualize interphase chromatin, the data presented support the hypothesis that chromatin dynamic changes during cell-cycle are important determinants in the conversion of sub-microscopic DNA lesions into chromatid breaks. Consequently, the type and yield of radiation-induced chromosomal aberrations at a given cell-cycle-stage depends on the combined effect of DNA repair processes and chromatin dynamics, which is cell-cycle-regulated and subject to up- or down-regulation following radiation exposure or genetic alterations. This new hypothesis is used to explain the variability in radiosensitivity observed at various cell-cycle-stages, among mutant cells and cells of different origin, or among different individuals, and to revisit unresolved issues and unanswered questions. In addition, it is used to better understand hypersensitivity of AT cells and to provide an improved predictive G2-assay for evaluating radiosensitivity at individual level. Finally, experimental data at single cell level obtained using hybrid cells suggest that the proposed hypothesis applies only to the irradiated component of the hybrid.

  15. Cell cycle arrest and cell survival induce reverse trends of cardiolipin remodeling.

    Directory of Open Access Journals (Sweden)

    Yu-Jen Chao

    Full Text Available Cell survival from the arrested state can be a cause of the cancer recurrence. Transition from the arrest state to the growth state is highly regulated by mitochondrial activity, which is related to the lipid compositions of the mitochondrial membrane. Cardiolipin is a critical phospholipid for the mitochondrial integrity and functions. We examined the changes of cardiolipin species by LC-MS in the transition between cell cycle arrest and cell reviving in HT1080 fibrosarcoma cells. We have identified 41 cardiolipin species by MS/MS and semi-quantitated them to analyze the detailed changes of cardiolipin species. The mass spectra of cardiolipin with the same carbon number form an envelope, and the C64, C66, C68, C70 C72 and C74 envelopes in HT1080 cells show a normal distribution in the full scan mass spectrum. The cardiolipin quantity in a cell decreases while entering the cell cycle arrest, but maintains at a similar level through cell survival. While cells awakening from the arrested state and preparing itself for replication, the groups with short acyl chains, such as C64, C66 and C68 show a decrease of cardiolipin percentage, but the groups with long acyl chains, such as C70 and C72 display an increase of cardiolipin percentage. Interestingly, the trends of the cardiolipin species changes during the arresting state are completely opposite to cell growing state. Our results indicate that the cardiolipin species shift from the short chain to long chain cardiolipin during the transition from cell cycle arrest to cell progression.

  16. Effect of p27KIP1 on cell cycle and apoptosis in gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Jian-Yong Zheng; Wei-Zhong Wang; Kai-Zong Li; Wen-Xian Guan; Wei Yan

    2005-01-01

    AIM: To elucidate the effect of p27KIP1 on cell cycle and apoptosis regulation in gastric carcinoma cells.METHODS: The whole length of p27KIP1 cDNA was transfected into human gastric cancer cell line SCG7901by lipofectamine. Expression of p27KIP1 protein or mRNA was analyzed by Western blot and RNA dot blotting,respectively. Effect of p27KIP1 on cell growth was observed by MTT assay and anchorage-independent growth in soft agar. Tumorigenicity in nude mice was used to assess the in vivo biological effect of p27KIP1. Flow cytometry,TUNEL, and electron microscopy were used to assess the effect of p27KIP1 on cell cycle and apoptosis.RESULTS: Expression of p27KIP1 protein or mRNA increased evidently in SCG7901 cells transfected with p27KIP1. The cell growth was reduced by 31% at 48 h after induction with zinc determined by cell viability assay. The alteration of cell malignant phenotype was evidently indicated by the loss of anchorage-independent growth ability in soft agar. The tumorigenicity in nude mice was reduced evidently (0.55±0.14 cm vs 1.36±0.13crn, P<0.01). p27KIP1 overexpression caused cell arrest with 36% increase (from 33.7% to 69.3%,P<0.01) in G1 population. Prolonged p27KIP1 expression induced apoptotic cell death reflected by pre-G1 peak in the histogram of FACS, which was also confirmed by TUNEL assay and electron microscopy.CONCLUSION: p27KIP1 can prolong cell cycle in G1phase and lead to apoptosis. p27KIP1 may be a good candidate for cancer gene therapy.

  17. Effect of polo-like kinase 1 gene silence on cell cycle and drug resistance in K562/A02 cell

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ Polo-like kinase 1(PLK1) plays an important role in many cell-cycle-related events.1 At G2/M transition, PLK1 contributes to the activation of cyclinB/Cdc by phosphorylation of Cdc25C, centrosome functional maturation, bipolar spindle formation. In later stage of mitosis, PLK1 is involved in regulating components of the anaphase-promoting complex (APC) for mitotic exit and in the execution of cytokinesis.

  18. TNF-α induces apoptosis of Molt-4 cells and cell cycle specificity of Bcl-2 phosphyrylation

    Institute of Scientific and Technical Information of China (English)

    Changyong Yang; Huijie Zhao; Jianping Gong

    2010-01-01

    Objective:The aim of the study was to observe the expression of Bcl-2 and its phosphorylation in Molt-4 cells induced by tumor necrosis factor-α(TNF-α),and to investigate the possible mechanism of cell cycle specificity of apoptosis.Methods:Exponentially growing Molt-4 cells were treated with TNF-α.Apoptosis was detected by DNA fragmentation assay.API method was applied to illustrate the cell cycle specificity of apoptotic cells.Cells of sub-phases were sorted by FACSvantage flow cytometer and then submitted to immunoblot.Results:Molt-4 cells which were treated with TNF-α went to apoptosis and showed a DNA ladder pattern.Most apoptosis happened in G1-phase of cell cycle.Bcl-2 expression increased for the Molt-4 cells treated with TNF-α.The phosphorylation state of Bcl-2 was only presented in G1-phase cells,in accordance with the specified time and cell cycle phase of apoptosis.Conclusion:The phosphorylation of Bcl-2 in the Molt-4 cells treated with TNF-α happened with the same cell cycle specificity as cell apoptosis.The cell cycle specificity of Bcl-2 phosphorylation was one of the mechanisms of receptor-mediated apoptosis.The cell cycle machine can trigger the apoptosis program.

  19. Restrictions in cell cycle progression of adult vestibular supporting cells in response to ectopic cyclin D1 expression.

    Directory of Open Access Journals (Sweden)

    Heidi Loponen

    Full Text Available Sensory hair cells and supporting cells of the mammalian inner ear are quiescent cells, which do not regenerate. In contrast, non-mammalian supporting cells have the ability to re-enter the cell cycle and produce replacement hair cells. Earlier studies have demonstrated cyclin D1 expression in the developing mouse supporting cells and its downregulation along maturation. In explant cultures of the mouse utricle, we have here focused on the cell cycle control mechanisms and proliferative potential of adult supporting cells. These cells were forced into the cell cycle through adenoviral-mediated cyclin D1 overexpression. Ectopic cyclin D1 triggered robust cell cycle re-entry of supporting cells, accompanied by changes in p27(Kip1 and p21(Cip1 expressions. Main part of cell cycle reactivated supporting cells were DNA damaged and arrested at the G2/M boundary. Only small numbers of mitotic supporting cells and rare cells with signs of two successive replications were found. Ectopic cyclin D1-triggered cell cycle reactivation did not lead to hyperplasia of the sensory epithelium. In addition, a part of ectopic cyclin D1 was sequestered in the cytoplasm, reflecting its ineffective nuclear import. Combined, our data reveal intrinsic barriers that limit proliferative capacity of utricular supporting cells.

  20. Dual Pressure versus Hybrid Recuperation in an Integrated Solid Oxide Fuel Cell Cycle – Steam Cycle

    DEFF Research Database (Denmark)

    Rokni, Masoud

    2014-01-01

    steam in a HRSG (heat recovery steam generator). The bottoming steam cycle was modeled with two configurations: (1) a simple single pressure level and (2) a dual pressure level with both a reheat and a pre-heater. The SOFC stacks in the present SOFC-ST hybrid cycles were not pressurized. The dual...

  1. The Global Regulatory Architecture of Transcription during the Caulobacter Cell Cycle

    Science.gov (United States)

    Zhou, Bo; Schrader, Jared M.; Kalogeraki, Virginia S.; Abeliuk, Eduardo; Dinh, Cong B.; Pham, James Q.; Cui, Zhongying Z.; Dill, David L.; McAdams, Harley H.; Shapiro, Lucy

    2015-01-01

    Each Caulobacter cell cycle involves differentiation and an asymmetric cell division driven by a cyclical regulatory circuit comprised of four transcription factors (TFs) and a DNA methyltransferase. Using a modified global 5′ RACE protocol, we globally mapped transcription start sites (TSSs) at base-pair resolution, measured their transcription levels at multiple times in the cell cycle, and identified their transcription factor binding sites. Out of 2726 TSSs, 586 were shown to be cell cycle-regulated and we identified 529 binding sites for the cell cycle master regulators. Twenty-three percent of the cell cycle-regulated promoters were found to be under the combinatorial control of two or more of the global regulators. Previously unknown features of the core cell cycle circuit were identified, including 107 antisense TSSs which exhibit cell cycle-control, and 241 genes with multiple TSSs whose transcription levels often exhibited different cell cycle timing. Cumulatively, this study uncovered novel new layers of transcriptional regulation mediating the bacterial cell cycle. PMID:25569173

  2. The global regulatory architecture of transcription during the Caulobacter cell cycle.

    Directory of Open Access Journals (Sweden)

    Bo Zhou

    2015-01-01

    Full Text Available Each Caulobacter cell cycle involves differentiation and an asymmetric cell division driven by a cyclical regulatory circuit comprised of four transcription factors (TFs and a DNA methyltransferase. Using a modified global 5' RACE protocol, we globally mapped transcription start sites (TSSs at base-pair resolution, measured their transcription levels at multiple times in the cell cycle, and identified their transcription factor binding sites. Out of 2726 TSSs, 586 were shown to be cell cycle-regulated and we identified 529 binding sites for the cell cycle master regulators. Twenty-three percent of the cell cycle-regulated promoters were found to be under the combinatorial control of two or more of the global regulators. Previously unknown features of the core cell cycle circuit were identified, including 107 antisense TSSs which exhibit cell cycle-control, and 241 genes with multiple TSSs whose transcription levels often exhibited different cell cycle timing. Cumulatively, this study uncovered novel new layers of transcriptional regulation mediating the bacterial cell cycle.

  3. Treatment Options by Stage (Small Cell Lung Cancer)

    Science.gov (United States)

    ... lung cancer is a disease in which malignant (cancer) cells form in the tissues of the lung. The ... diagnosed, tests are done to find out if cancer cells have spread within the chest or to other ...

  4. Treatment Options By Stage (Ovarian Germ Cell Tumors)

    Science.gov (United States)

    ... ovarian germ cell tumor are swelling of the abdomen or vaginal bleeding after menopause. Ovarian germ cell ... if you have either of the following: Swollen abdomen without weight gain in other parts of the ...

  5. Interim PET After Two ABVD Cycles in Early-Stage Hodgkin Lymphoma: Outcomes Following the Continuation of Chemotherapy Plus Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Simontacchi, Gabriele [Radiotherapy Unit, Azienda Ospedaliera Universitaria Careggi, University of Florence, Florence (Italy); Filippi, Andrea Riccardo, E-mail: andreariccardo.filippi@unito.it [Department of Oncology, University of Torino, Torino (Italy); Ciammella, Patrizia [Radiation Oncology Unit, Department of Advanced Technology, Arcispedale Santa Maria Nuova, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia (Italy); Buglione, Michela [Radiation Oncology Department, University and Spedali Civili, Brescia (Italy); Saieva, Calogero [Molecular and Nutritional Epidemiology Unit, Cancer Research and Prevention Institute, Florence (Italy); Magrini, Stefano Maria [Radiation Oncology Department, University and Spedali Civili, Brescia (Italy); Livi, Lorenzo [Radiotherapy Unit, Azienda Ospedaliera Universitaria Careggi, University of Florence, Florence (Italy); Iotti, Cinzia [Radiation Oncology Unit, Department of Advanced Technology, Arcispedale Santa Maria Nuova, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia (Italy); Botto, Barbara [Hematology Unit, Città della Salute e della Scienza Hospital, Torino (Italy); Vaggelli, Luca [Nuclear Medicine Department, Azienda Ospedaliera Universitaria Careggi, University of Florence, Florence (Italy); Re, Alessandro [Hematology Unit, University and Spedali Civili, Brescia (Italy); Merli, Francesco [Hematology Unit, Arcispedale Santa Maria Nuova, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia (Italy); Ricardi, Umberto [Department of Oncology, University of Torino, Torino (Italy)

    2015-08-01

    Purpose: This multicenter retrospective study was designed to evaluate the prognostic role of interim fluorodeoxyglucose-labeled positron emission tomography (i-FDG-PET) in a cohort of patients affected with early-stage Hodgkin lymphoma (HL) treated initially with adriamycin, bleomycin, vinblastine, dacarbazine (ABVD) chemotherapy followed by radiation therapy, and to assess the role of chemotherapy continuation plus radiation therapy for i-FDG-PET-positive patients. Methods and Materials: Data from 257 patients were retrieved from 4 hematology and radiation oncology departments. Inclusion criteria were stage I to IIAB HL, “intention-to-treat” AVBD plus radiation therapy, and FDG-PET at diagnosis and after the first 2 ABVD cycles. All i-FDG-PET scans underwent blinded local review by using the Deauville 5-point scoring system; patients were stratified as negative or positive using 2 Deauville score cutoff values, ≥3 or ≥4. Results: Median follow-up time was 56 months (range: 9-163 months); 5-year overall survival (OS) and disease-specific survival (DSS) for the whole cohort were 97.5% and 98.3%, respectively. Five-year progression-free survival (PFS) was 95.6%. After i-FDG-PET revision, 43 of 257 patients (16.7%) had a positive i-FDG-PET (Deauville scores: 3-5). Five-year PFS rates for i-FDG-PET-negative and i-FDG-PET-positive patients were 98.1% and 83.7%, respectively, if using a Deauville score cutoff of 3, and 97.7% and 78.6%, respectively, if using a cutoff of 4 (P=.0001). Five-year OS for i-FDG-PET-negative and i-FDG-PET-positive patients was 98.5% and 93.0%, respectively, if using a cutoff of 3, and 98.6% and 89.3%, respectively, if using a cutoff of 4 (P=.029 and P=.002). At univariate regression analysis, i-FDG-PET positivity was associated with worse OS and PFS. At multivariate analysis, performed only for PFS, i-FDG-PET positivity confirmed its negative impact (P=.002). Conclusions: i-FDG-PET is prognostic for PFS and OS in early-stage HL

  6. Coupling between the circadian clock and cell cycle oscillators : implication for healthy cells and malignant growth

    OpenAIRE

    Feillet, Céline‏; Horst, Gijsbertus Theodorus Johannes van der‏; Lévi, Francis A.; Rand, D. A.; Delaunay, Franck

    2015-01-01

    Uncontrolled cell proliferation is one of the key features leading to cancer. Seminal works in chronobiology have revealed that disruption of the circadian timing system in mice, either by surgical, genetic, or environmental manipulation, increased tumor development. In humans, shift work is a risk factor for cancer. Based on these observations, the link between the circadian clock and cell cycle has become intuitive. But despite identification of molecular connections between the two process...

  7. An integrative model and analysis of cell cycle in fission yeast

    Institute of Scientific and Technical Information of China (English)

    TENG Hu; HUANG Xun; XIU Zhilong; FENG Enmin

    2005-01-01

    According to the recent investigation on cell cycle of fission yeast, a mathematical dynamic model is formulated. Four cyclins, e.g. Puc1, Cig1, Cig2 and Cdc13, are investigated here. The interacting networks between the cyclins and the process of cell cycle are mathematically described. The functions of these cyclins are particularly analyzed. Comparison among different mutants indicates that the cyclins play an important role in cell cycle.

  8. Test summary for advanced H2 cycle NI-CD cell

    Science.gov (United States)

    Miller, Lee

    1987-01-01

    To improve operational tolerances and mass, the H2 gas recombination design provisions of the Ni-H2 system were incorporated into the sealed Ni-Cd system. Produced is a cell design capable of operating on the H2 cycle versus the normal O2 cycle. Three test cells have now completed approximately 4,330 LEO (90 minute) cycles at 20 percent depth of discharge (DOD). Performance remains stable although one cell exhibited a temporary pressure anomaly.

  9. Curcumin inhibits growth potential by G1 cell cycle arrest and induces apoptosis in p53-mutated COLO 320DM human colon adenocarcinoma cells.

    Science.gov (United States)

    Dasiram, Jade Dhananjay; Ganesan, Ramamoorthi; Kannan, Janani; Kotteeswaran, Venkatesan; Sivalingam, Nageswaran

    2017-02-01

    Curcumin, a natural polyphenolic compound and it is isolated from the rhizome of Curcuma longa, have been reported to possess anticancer effect against stage I and II colon cancer. However, the effect of curcumin on colon cancer at Dukes' type C metastatic stage III remains still unclear. In the present study, we have investigated the anticancer effects of curcumin on p53 mutated COLO 320DM human colon adenocarcinoma cells derived from Dukes' type C metastatic stage. The cellular viability and proliferation were assessed by trypan blue exclusion assay and MTT assay, respectively. The cytotoxicity effect was examined by lactate dehydrogenase (LDH) cytotoxicity assay. Apoptosis was analyzed by DNA fragmentation analysis, Hoechst and propidium iodide double fluorescent staining and confocal microscopy analysis. Cell cycle distribution was performed by flow cytometry analysis. Here we have observed that curcumin treatment significantly inhibited the cellular viability and proliferation potential of p53 mutated COLO 320DM cells in a dose- and time-dependent manner. In addition, curcumin treatment showed no cytotoxic effects to the COLO 320DM cells. DNA fragmentation analysis, Hoechst and propidium iodide double fluorescent staining and confocal microscopy analysis revealed that curcumin treatment induced apoptosis in COLO 320DM cells. Furthermore, curcumin caused cell cycle arrest at the G1 phase, decreased the cell population in the S phase and induced apoptosis in COLO 320DM colon adenocarcinoma cells. Together, these data suggest that curcumin exerts anticancer effects and induces apoptosis in p53 mutated COLO 320DM human colon adenocarcinoma cells derived from Dukes' type C metastatic stage.

  10. Cell cycle phase influences tumour cell sensitivity to aminolaevulinic acid-induced photodynamic therapy in vitro.

    Science.gov (United States)

    Wyld, L.; Smith, O.; Lawry, J.; Reed, M. W.; Brown, N. J.

    1998-01-01

    Photodynamic therapy (PDT) is a form of cancer treatment based on the destruction of cells by the interaction of light, oxygen and a photosensitizer. Aminolaevulinic acid (ALA) is the prodrug of the photosensitizer protoporphyrin IX (PpIX). ALA-induced PDT depends on the rate of cellular synthesis of PpIX, which may vary with cell cycle phase. This study has investigated the relationship between cell cycle phase, PpIX generation and phototoxicity in synchronized and unsynchronized bladder cancer cells (HT1197). In unsynchronized cells, relative PpIX fluorescence values (arbitrary units) were significantly different between cell cycle phases after a 1-h ALA incubation (G1 24.8 +/- 0.7; S-phase, 32.7 +/- 0.8, P < 0.05; G2 35.4 +/- 0.8, P < 0.05). In synchronized cells after a 1-h ALA incubation, cells in G1 produced less PpIX than those in S-phase or G2 [6.65 +/- 1.1 ng per 10(5) cells compared with 15.5 +/- 2.1 (P < 0.05), and 8.1 +/- 1.8 ng per 10(5) cells (not significant) respectively] and were significantly less sensitive to ALA-induced PDT (% survival, G1 76.2 +/- 8.3; S-phase 49.7 +/- 4.6, P < 0.05; G2 44.2 +/- 2.4, P < 0.05). This differential response in tumour cells may have implications for clinical PDT, resulting in treatment resistance and possible failure in complete tumour response. PMID:9662250

  11. Cell cycle specificity of cytogenetic damage induced by 3,4-epoxy-1- butene.

    Science.gov (United States)

    Kligerman, A D; Doerr, C L; Tennant, A H

    1999-07-21

    3,4-epoxy-1-butene (EB), a primary metabolite of butadiene, is a direct-acting "S-dependent" genotoxicant that can induce sister chromatid exchanges (SCEs) and chromosome aberrations (CAs) in cycling cells in vitro. However, EB is almost inactive when splenic or peripheral blood lymphocytes are exposed at the G(0) stage of the cell cycle. To investigate whether repair of DNA lesions is responsible for the lack of cytogenetic responses seen after G(0) treatments, we used cytosine arabinoside (ara-C) to inhibit DNA polymerization during DNA repair. If enough repairable lesions are present, double-strand breaks should accumulate and form chromosome-type ("S-independent") deletions and exchanges. This is exactly what occurred. EB induced chromosome deletions and dicentrics at the first division following treatment, when the EB exposure was followed by ara-C. Without ara-C treatment, there was no induction of CAs. These experiments indicate that the relatively low levels of damage induced by EB in G(0) lymphocytes are removed by DNA repair prior to DNA synthesis and thus, before the production of SCEs or chromatid-type aberrations.

  12. Function of trehalose and glycogen in cell cycle progression and cell viability in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Silljé, H H; Paalman, J W; ter Schure, E G; Olsthoorn, S Q; Verkleij, A J; Boonstra, Johannes; Verrips, C T

    1999-01-01

    Trehalose and glycogen accumulate in Saccharomyces cerevisiae when growth conditions deteriorate. It has been suggested that aside from functioning as storage factors and stress protectants, these carbohydrates may be required for cell cycle progression at low growth rates under carbon limitation. B

  13. Influence of cell cycle on responses of MCF-7 cells to benzo[a]pyrene

    Directory of Open Access Journals (Sweden)

    Giddings Ian

    2011-06-01

    Full Text Available Abstract Background Benzo[a]pyrene (BaP is a widespread environmental genotoxic carcinogen that damages DNA by forming adducts. This damage along with activation of the aryl hydrocarbon receptor (AHR induces complex transcriptional responses in cells. To investigate whether human cells are more susceptible to BaP in a particular phase of the cell cycle, synchronised breast carcinoma MCF-7 cells were exposed to BaP. Cell cycle progression was analysed by flow cytometry, DNA adduct formation was assessed by 32P-postlabeling analysis, microarrays of 44K human genome-wide oligos and RT-PCR were used to detect gene expression (mRNA changes and Western blotting was performed to determine the expression of some proteins, including cytochrome P450 (CYP 1A1 and CYP1B1, which are involved in BaP metabolism. Results Following BaP exposure, cells evaded G1 arrest and accumulated in S-phase. Higher levels of DNA damage occurred in S- and G2/M- compared with G0/G1-enriched cultures. Genes that were found to have altered expression included those involved in xenobiotic metabolism, apoptosis, cell cycle regulation and DNA repair. Gene ontology and pathway analysis showed the involvement of various signalling pathways in response to BaP exposure, such as the Catenin/Wnt pathway in G1, the ERK pathway in G1 and S, the Nrf2 pathway in S and G2/M and the Akt pathway in G2/M. An important finding was that higher levels of DNA damage in S- and G2/M-enriched cultures correlated with higher levels of CYP1A1 and CYP1B1 mRNA and proteins. Moreover, exposure of synchronised MCF-7 cells to BaP-7,8-diol-9,10-epoxide (BPDE, the ultimate carcinogenic metabolite of BaP, did not result in significant changes in DNA adduct levels at different phases of the cell cycle. Conclusions This study characterised the complex gene response to BaP in MCF-7 cells and revealed a strong correlation between the varying efficiency of BaP metabolism and DNA damage in different phases of the cell

  14. Arctigenin induces cell cycle arrest by blocking the phosphorylation of Rb via the modulation of cell cycle regulatory proteins in human gastric cancer cells.

    Science.gov (United States)

    Jeong, Jin Boo; Hong, Se Chul; Jeong, Hyung Jin; Koo, Jin Suk

    2011-10-01

    Gastric cancer is a leading cause of cancer-related deaths, worldwide being second only to lung cancer as a cause of death. Arctigenin, a representative dibenzylbutyrolactone lignan, occurs in a variety of plants. However, the molecular mechanisms of arctigenin for anti-tumor effect on gastric cancer have not been examined. This study examined the biological effects of arctigenin on the human gastric cancer cell line SNU-1 and AGS. Cell proliferation was determined by MTT assay. In MTT assay, the proliferation of SNU-1 and AGS cells was significantly inhibited by arctigenin in a time and dose dependent manner, as compared with SNU-1 and AGS cells cultured in the absence of arctigenin. Inhibition of cell proliferation by arctigenin was in part associated with apoptotic cell death, as shown by changes in the expression ratio of Bcl-2 to Bax by arctigenin. Also, arctigenin blocked cell cycle arrest from G(1) to S phase by regulating the expression of cell cycle regulatory proteins such as Rb, cyclin D1, cyclin E, CDK4, CDK2, p21Waf1/Cip1 and p15 INK4b. The antiproliferative effect of arctigenin on SNU-1 and AGS gastric cancer cells revealed in this study suggests that arctigenin has intriguing potential as a chemopreventive or chemotherapeutic agent.

  15. Examination of oxygen release from plants in constructed wetlands in different stages of wetland plant life cycle.

    Science.gov (United States)

    Zhang, Jian; Wu, Haiming; Hu, Zhen; Liang, Shuang; Fan, Jinlin

    2014-01-01

    The quantification of oxygen release by plants in different stages of wetland plant life cycle was made in this study. Results obtained from 1 year measurement in subsurface wetland microcosms demonstrated that oxygen release from Phragmites australis varied from 108.89 to 404.44 mg O₂/m(2)/d during the different periods from budding to dormancy. Plant species, substrate types, and culture solutions had a significant effect on the capacity of oxygen release of wetland plants. Oxygen supply by wetland plants was estimated to potentially support a removal of 300.37 mg COD/m(2)/d or 55.87 mg NH₄-N/m(2)/d. According to oxygen balance analysis, oxygen release by plants could provide 0.43-1.12% of biochemical oxygen demand in typical subsurface-flow constructed wetlands (CWs). This demonstrates that oxygen release of plants may be a potential source for pollutants removal especially in low-loaded CWs. The results make it possible to quantify the role of plants in wastewater purification.

  16. Slow-cycling stem cells in hydra contribute to head regeneration

    Directory of Open Access Journals (Sweden)

    Niraimathi Govindasamy

    2014-11-01

    Full Text Available Adult stem cells face the challenge of maintaining tissue homeostasis by self-renewal while maintaining their proliferation potential over the lifetime of an organism. Continuous proliferation can cause genotoxic/metabolic stress that can compromise the genomic integrity of stem cells. To prevent stem cell exhaustion, highly proliferative adult tissues maintain a pool of quiescent stem cells that divide only in response to injury and thus remain protected from genotoxic stress. Hydra is a remarkable organism with highly proliferative stem cells and ability to regenerate at whole animal level. Intriguingly, hydra does not display consequences of high proliferation, such as senescence or tumour formation. In this study, we investigate if hydra harbours a pool of slow-cycling stem cells that could help prevent undesirable consequences of continuous proliferation. Hydra were pulsed with the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU and then chased in the absence of EdU to monitor the presence of EdU-retaining cells. A significant number of undifferentiated cells of all three lineages in hydra retained EdU for about 8–10 cell cycles, indicating that these cells did not enter cell cycle. These label-retaining cells were resistant to hydroxyurea treatment and were predominantly in the G2 phase of cell cycle. Most significantly, similar to mammalian quiescent stem cells, these cells rapidly entered cell division during head regeneration. This study shows for the first time that, contrary to current beliefs, cells in hydra display heterogeneity in their cell cycle potential and the slow-cycling cells in this population enter cell cycle during head regeneration. These results suggest an early evolution of slow-cycling stem cells in multicellular animals.

  17. Programmed cell cycle arrest is required for infection of corn plants by the fungus Ustilago maydis.

    Science.gov (United States)

    Castanheira, Sónia; Mielnichuk, Natalia; Pérez-Martín, José

    2014-12-01

    Ustilago maydis is a plant pathogen that requires a specific structure called infective filament to penetrate the plant tissue. Although able to grow, this filament is cell cycle arrested on the plant surface. This cell cycle arrest is released once the filament penetrates the plant tissue. The reasons and mechanisms for this cell cycle arrest are unknown. Here, we have tried to address these questions. We reached three conclusions from our studies. First, the observed cell cycle arrest is the result of the cooperation of at least two distinct mechanisms: one involving the activation of the DNA damage response (DDR) cascade; and the other relying on the transcriptional downregulation of Hsl1, a kinase that modulates the G2/M transition. Second, a sustained cell cycle arrest during the infective filament step is necessary for the virulence in U. maydis, as a strain unable to arrest the cell cycle was severely impaired in its ability to infect corn plants. Third, production of the appressorium, a structure required for plant penetration, is incompatible with an active cell cycle. The inability to infect plants by strains defective in cell cycle arrest seems to be caused by their failure to induce the appressorium formation process. In summary, our findings uncover genetic circuits to arrest the cell cycle during the growth of this fungus on the plant surface, thus allowing the penetration into plant tissue.

  18. c-Myc is a novel target of cell cycle arrest by honokiol in prostate cancer cells.

    Science.gov (United States)

    Hahm, Eun-Ryeong; Singh, Krishna Beer; Singh, Shivendra V

    2016-09-01

    Honokiol (HNK), a highly promising phytochemical derived from Magnolia officinalis plant, exhibits in vitro and in vivo anticancer activity against prostate cancer but the underlying mechanism is not fully clear. This study was undertaken to delineate the role of c-Myc in anticancer effects of HNK. Exposure of prostate cancer cells to plasma achievable doses of HNK resulted in a marked decrease in levels of total and/or phosphorylated c-Myc protein as well as its mRNA expression. We also observed suppression of c-Myc protein in PC-3 xenografts upon oral HNK administration. Stable overexpression of c-Myc in PC-3 and 22Rv1 cells conferred significant protection against HNK-mediated growth inhibition and G0-G1 phase cell cycle arrest. HNK treatment decreased expression of c-Myc downstream targets including Cyclin D1 and Enhancer of Zeste Homolog 2 (EZH2), and these effects were partially restored upon c-Myc overexpression. In addition, PC-3 and DU145 cells with stable knockdown of EZH2 were relatively more sensitive to growth inhibition by HNK compared with control cells. Finally, androgen receptor overexpression abrogated HNK-mediated downregulation of c-Myc and its targets particularly EZH2. The present study indicates that c-Myc, which is often overexpressed in early and late stages of human prostate cancer, is a novel target of prostate cancer growth inhibition by HNK.

  19. Circadian clock regulation of the cell cycle in the zebrafish intestine.

    Directory of Open Access Journals (Sweden)

    Elodie Peyric

    Full Text Available The circadian clock controls cell proliferation in a number of healthy tissues where cell renewal and regeneration are critical for normal physiological function. The intestine is an organ that typically undergoes regular cycles of cell division, differentiation and apoptosis as part of its role in digestion and nutrient absorption. The aim of this study was to explore circadian clock regulation of cell proliferation and cell cycle gene expression in the zebrafish intestine. Here we show that the zebrafish gut contains a directly light-entrainable circadian pacemaker, which regulates the daily timing of mitosis. Furthermore, this intestinal clock controls the expression of key cell cycle regulators, such as cdc2, wee1, p21, PCNA and cdk2, but only weakly influences cyclin B1, cyclin B2 and cyclin E1 expression. Interestingly, food deprivation has little impact on circadian clock function in the gut, but dramatically reduces cell proliferation, as well as cell cycle gene expression in this tissue. Timed feeding under constant dark conditions is able to drive rhythmic expression not only of circadian clock genes, but also of several cell cycle genes, suggesting that food can entrain the clock, as well as the cell cycle in the intestine. Rather surprisingly, we found that timed feeding is critical for high amplitude rhythms in cell cycle gene expression, even when zebrafish are maintained on a light-dark cycle. Together these results suggest that the intestinal clock integrates multiple rhythmic cues, including light and food, to function optimally.

  20. Circadian clock regulation of the cell cycle in the zebrafish intestine.

    Science.gov (United States)

    Peyric, Elodie; Moore, Helen A; Whitmore, David

    2013-01-01

    The circadian clock controls cell proliferation in a number of healthy tissues where cell renewal and regeneration are critical for normal physiological function. The intestine is an organ that typically undergoes regular cycles of cell division, differentiation and apoptosis as part of its role in digestion and nutrient absorption. The aim of this study was to explore circadian clock regulation of cell proliferation and cell cycle gene expression in the zebrafish intestine. Here we show that the zebrafish gut contains a directly light-entrainable circadian pacemaker, which regulates the daily timing of mitosis. Furthermore, this intestinal clock controls the expression of key cell cycle regulators, such as cdc2, wee1, p21, PCNA and cdk2, but only weakly influences cyclin B1, cyclin B2 and cyclin E1 expression. Interestingly, food deprivation has little impact on circadian clock function in the gut, but dramatically reduces cell proliferation, as well as cell cycle gene expression in this tissue. Timed feeding under constant dark conditions is able to drive rhythmic expression not only of circadian clock genes, but also of several cell cycle genes, suggesting that food can entrain the clock, as well as the cell cycle in the intestine. Rather surprisingly, we found that timed feeding is critical for high amplitude rhythms in cell cycle gene expression, even when zebrafish are maintained on a light-dark cycle. Together these results suggest that the intestinal clock integrates multiple rhythmic cues, including light and food, to function optimally.

  1. Tetrahydrouridine inhibits cell proliferation through cell cycle regulation regardless of cytidine deaminase expression levels.

    Directory of Open Access Journals (Sweden)

    Naotake Funamizu

    Full Text Available Tetrahydrouridine (THU is a well characterized and potent inhibitor of cytidine deaminase (CDA. Highly expressed CDA catalyzes and inactivates cytidine analogues, ultimately contributing to increased gemcitabine resistance. Therefore, a combination therapy of THU and gemcitabine is considered to be a potential and promising treatment for tumors with highly expressed CDA. In this study, we found that THU has an alternative mechanism for inhibiting cell growth which is independent of CDA expression. Three different carcinoma cell lines (MIAPaCa-2, H441, and H1299 exhibited decreased cell proliferation after sole administration of THU, while being unaffected by knocking down CDA. To investigate the mechanism of THU-induced cell growth inhibition, cell cycle analysis using flow cytometry was performed. This analysis revealed that THU caused an increased rate of G1-phase occurrence while S-phase occurrence was diminished. Similarly, Ki-67 staining further supported that THU reduces cell proliferation. We also found that THU regulates cell cycle progression at the G1/S checkpoint by suppressing E2F1. As a result, a combination regimen of THU and gemcitabine might be a more effective therapy than previously believed for pancreatic carcinoma since THU works as a CDA inhibitor, as well as an inhibitor of cell growth in some types of pancreatic carcinoma cells.

  2. Manipulation of Cell Cycle and Chromatin Configuration by Means of Cell-Penetrating Geminin.

    Directory of Open Access Journals (Sweden)

    Yoshinori Ohno

    Full Text Available Geminin regulates chromatin remodeling and DNA replication licensing which play an important role in regulating cellular proliferation and differentiation. Transcription of the Geminin gene is regulated via an E2F-responsive region, while the protein is being closely regulated by the ubiquitin-proteasome system. Our objective was to directly transduce Geminin protein into cells. Recombinant cell-penetrating Geminin (CP-Geminin was generated by fusing Geminin with a membrane translocating motif from FGF4 and was efficiently incorporated into NIH 3T3 cells and mouse embryonic fibroblasts. The withdrawal study indicated that incorporated CP-Geminin was quickly reduced after removal from medium. We confirmed CP-Geminin was imported into the nucleus after incorporation and also that the incorporated CP-Geminin directly interacted with Cdt1 or Brahma/Brg1 as the same manner as Geminin. We further demonstrated that incorporated CP-Geminin suppressed S-phase progression of the cell cycle and reduced nuclease accessibility in the chromatin, probably through suppression of chromatin remodeling, indicating that CP-Geminin constitutes a novel tool for controlling chromatin configuration and the cell cycle. Since Geminin has been shown to be involved in regulation of stem cells and cancer cells, CP-Geminin is expected to be useful for elucidating the role of Geminin in stem cells and cancer cells, and for manipulating their activity.

  3. An analysis of the growth of the retinal cell population in embryonic chicks yielding proliferative ratios, numbers of proliferative and non-proliferative cells and cell-cycle times for successive generations of cell cycles.

    Science.gov (United States)

    Morris, V B; Cowan, R

    1995-07-01

    Growth curves of the retinal cell population of embryonic chicks were fitted by a branching-process model of cell population growth, thereby estimating the proliferative ratios and mean cell-cycle times of the generations of cell cycles that underlie retinal growth. The proliferative ratio determines the proportion of cells that divides in the next generation, so the numbers of proliferative and non-proliferative cells in each generation of cell cycles were obtained. The mean cell-cycle times determine the times over which the generations are extant. Assuming growth starts from one cell in generation 0, the proliferative cells reach 3.6 x 10(6) and the non-proliferative cells reach 1.1 x 10(6) by generation 23. The next four generations increase the proliferative cell numbers to 13.9 x 10(6) and produce 20.1 x 10(6) non-proliferative cells. In the next five generations in the end phase of growth, non-proliferative cells are produced in large numbers at an average of 13.9 x 10(6) cells per generation as the retinal lineages are completed. The retinal cell population reaches a maximum estimated here at 98.2 x 10(6) cells. The mean cell-cycle time estimates range between 6.8 and 10.1 h in generations before the end phase of growth and between 10.6 and 17.2 h in generations in the end phase. The retinal cell population growth is limited by the depletion of the proliferative cell population that the production of non-proliferative cells entails. The proliferative ratios and the cell-cycle-time distribution parameters are the likely determinants of retinal growth rates. The results are discussed in relation to other results of spatial and temporal patterns of the cessation of cell cycling in the embryonic chick retina.

  4. Physiology of Saccharomyces cerevisiae during cell cycle oscillations.

    Science.gov (United States)

    Duboc, P; Marison, I; von Stockar, U

    1996-10-18

    Synchronized populations of Saccharomyces cerevisiae CBS 426 are characterized by autonomous oscillations of process variables. CO2 evolution rate, O2 uptake rate and heat production rate varied by a factor of 2 for a continuous culture grown at a dilution rate of 0.10 h-1. Elemental analysis showed that the carbon mass fraction of biomass did not change. Since the reactor is not at steady state, the elemental and energy balances were calculated on cumulated quantities, i.e. the integral of the reaction rates. It was possible to show that carbon, degree of reduction and energy balances matched. Application of simple mass balance principles for non-steady state systems indicated that oscillations were basically characterized by changes in biomass production rate. In addition, the amount of intermediates, e.g. ethanol or acetate, produced or consumed was negligible. Growth rate was low during the S-phase (0.075 h-1) and high during the G2, M and G1 phases (0.125 h-1) for a constant dilution rate of 0.10 h-1. However, nitrogen, ash, sulfur and potassium content showed systematic increases during the S-phase (bud initiation). Cell component analyses showed that changes in cellular fractions during oscillations (storage carbohydrate content decreased during the S-phase) were due to changes in production rates, particularly for protein and carbohydrates. Nevertheless, using the data evaluation techniques for dynamic systems presented here, it was shown that storage carbohydrates are not consumed during the S-phase. Only the synthesis rate of the different cell components changed depending on position in cell cycle. The growth process may be divided into two phenomena: the formation of new cells during mitosis with a low yield, and size increase of new born cells with high yield. Both kinetic and stoichiometric coefficients varied with the position in the oscillation: the results showed that biomass structure changed and that specific growth rate, as well as biomass yield

  5. Synchronization of Caulobacter crescentus for investigation of the bacterial cell cycle.

    Science.gov (United States)

    Schrader, Jared M; Shapiro, Lucy

    2015-04-08

    The cell cycle is important for growth, genome replication, and development in all cells. In bacteria, studies of the cell cycle have focused largely on unsynchronized cells making it difficult to order the temporal events required for cell cycle progression, genome replication, and division. Caulobacter crescentus provides an excellent model system for the bacterial cell cycle whereby cells can be rapidly synchronized in a G0 state by density centrifugation. Cell cycle synchronization experiments have been used to establish the molecular events governing chromosome replication and segregation, to map a genetic regulatory network controlling cell cycle progression, and to identify the establishment of polar signaling complexes required for asymmetric cell division. Here we provide a detailed protocol for the rapid synchronization of Caulobacter NA1000 cells. Synchronization can be performed in a large-scale format for gene expression profiling and western blot assays, as well as a small-scale format for microscopy or FACS assays. The rapid synchronizability and high cell yields of Caulobacter make this organism a powerful model system for studies of the bacterial cell cycle.

  6. Visualizing spatiotemporal dynamics of multicellular cell-cycle