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Sample records for aberrant cell wall

  1. Absence of fks1p in lager brewing yeast results in aberrant cell wall composition and improved beer flavor stability.

    Science.gov (United States)

    Wang, Jin-jing; Xu, Wei-na; Li, Xin'er; Li, Jia; Li, Qi

    2014-06-01

    The flavor stability during storage is very important to the freshness and shelf life of beer. However, beer fermented with a yeast strain which is prone to autolyze will significantly affect the flavor of product. In this study, the gene encoding β-1,3-glucan synthetase catalytic subunit (fks1) of the lager yeast was destroyed via self-clone strategy. β-1,3-glucan is the principle cell wall component, so fks1 disruption caused a decrease in β-1,3-glucan level and increase in chitin level in cell wall, resulting in the increased cell wall thickness. Comparing with wild-type strain, the mutant strain had 39.9 and 63.41 % less leakage of octanoic acid and decanoic acid which would significantly affect the flavor of beer during storage. Moreover, the results of European Brewery Convention tube fermentation test showed that the genetic manipulation to the industrial brewing yeast helped with the anti-staling ability, rather than affecting the fermentation ability. The thiobarbituric acid value reduced by 65.59 %, and the resistant staling value increased by 26.56 %. Moreover, the anti-staling index of the beer fermented with mutant strain increased by 2.64-fold than that from wild-type strain respectively. China has the most production and consumption of beer around the world, so the quality of beer has a significant impact on Chinese beer industry. The result of this study could help with the improvement of the quality of beer in China as well as around the world.

  2. Aberrant phenotypes in peripheral T cell lymphomas.

    Science.gov (United States)

    Hastrup, N; Ralfkiaer, E; Pallesen, G

    1989-01-01

    Seventy six peripheral T cell lymphomas were examined immunohistologically to test their reactivity with a panel of monoclonal antibodies against 11 T cell associated antigens (CD1-8, CD27, UCHL1, and the T cell antigen receptor). Sixty two (82%) lymphomas showed aberrant phenotypes, and four main categories were distinguished as follows: (i) lack of one or several pan-T cell antigens (49, 64% of the cases); (ii) loss of both the CD4 and CD8 antigens (11, 15% of the cases); (iii) coexpression of the CD4 and CD8 antigens (13, 17% of the cases); and (iv) expression of the CD1 antigen (eight, 11% of the cases). No correlation was seen between the occurrence of aberrant phenotypes and the histological subtype. It is concluded that the demonstration of an aberrant phenotype is a valuable supplement to histological assessment in the diagnosis of peripheral T cell lymphomas. It is recommended that the panel of monoclonal antibodies against T cell differentiation antigens should be fairly large, as apparently any antigen may be lost in the process of malignant transformation. Images Figure PMID:2469701

  3. Chromosome aberrations and cell survival in irradiated mammalian cells

    International Nuclear Information System (INIS)

    Tremp, J.

    1981-01-01

    A possible correlation between chromosome aberrations and reduced proliferation capacity or cell death was investigated. Synchronized Chinese hamster fibroblast cells were irradiated with 300 rad of x rays in early G 1 . Despite synchronization the cells reached the subsequent mitosis at different times. The frequency of chromosome aberrations was determined in the postirradiation division at 2-h intervals. The highest frequency occurred in cells with a first cell cycle of medium length. The colony-forming ability of mitotic cells was measured in parallel samples by following the progress of individual mitoses. The proportion of cells forming macrocolonies decreased with increasing cell cycle length, and the number of non-colony-forming cells increased. Irrespective of various first cell cycle lengths and different frequencies of chromosome aberrations, the number of cells forming microcolonies remained constant. A correlation was found between the absence of chromosome aberrations and the ability of cells to form macrocolonies. However, cells with a long first cell cycle formed fewer macrocolonies than expected

  4. Bacterial Cell Wall Components

    Science.gov (United States)

    Ginsberg, Cynthia; Brown, Stephanie; Walker, Suzanne

    Bacterial cell-surface polysaccharides cells are surrounded by a variety of cell-surface structures that allow them to thrive in extreme environments. Components of the cell envelope and extracellular matrix are responsible for providing the cells with structural support, mediating intercellular communication, allowing the cells to move or to adhere to surfaces, protecting the cells from attack by antibiotics or the immune system, and facilitating the uptake of nutrients. Some of the most important cell wall components are polysaccharide structures. This review discusses the occurrence, structure, function, and biosynthesis of the most prevalent bacterial cell surface polysaccharides: peptidoglycan, lipopolysaccharide, arabinogalactan, and lipoarabinomannan, and capsular and extracellular polysaccharides. The roles of these polysaccharides in medicine, both as drug targets and as therapeutic agents, are also described.

  5. Cell wall biology: perspectives from cell wall imaging.

    Science.gov (United States)

    Lee, Kieran J D; Marcus, Susan E; Knox, J Paul

    2011-03-01

    Polysaccharide-rich plant cell walls are important biomaterials that underpin plant growth, are major repositories for photosynthetically accumulated carbon, and, in addition, impact greatly on the human use of plants. Land plant cell walls contain in the region of a dozen major polysaccharide structures that are mostly encompassed by cellulose, hemicelluloses, and pectic polysaccharides. During the evolution of land plants, polysaccharide diversification appears to have largely involved structural elaboration and diversification within these polysaccharide groups. Cell wall chemistry is well advanced and a current phase of cell wall science is aimed at placing the complex polysaccharide chemistry in cellular contexts and developing a detailed understanding of cell wall biology. Imaging cell wall glycomes is a challenging area but recent developments in the establishment of cell wall molecular probe panels and their use in high throughput procedures are leading to rapid advances in the molecular understanding of the spatial heterogeneity of individual cell walls and also cell wall differences at taxonomic levels. The challenge now is to integrate this knowledge of cell wall heterogeneity with an understanding of the molecular and physiological mechanisms that underpin cell wall properties and functions.

  6. Cell wall evolution and diversity

    Directory of Open Access Journals (Sweden)

    Jonatan Ulrik Fangel

    2012-07-01

    Full Text Available Plant cell walls display a considerable degree of diversity in their compositions and molecular architectures. In some cases the functional significance of a particular cell wall type appears to be easy to discern: secondary cells walls are often heavy reinforced with lignin that provides the required durability; the thin cell walls of pollen tubes have particular compositions that enable their tip growth; lupin seed cell walls are characteristically thickened with galactan used as a storage polysaccharide. However, more frequently the evolutionary mechanisms and selection pressures that underpin cell wall diversity and evolution are unclear. The rapidly increasing availability of transcriptome and genome data sets, development of high-throughput methods for cell wall analyses, and expansion of molecular probe sets, are providing new insights into the diversity and occurrence of cell wall polysaccharides and associated biosynthetic genes. Such research is important for refining our understanding of some of the fundamental processes that enabled plants to colonise land and subsequently radiate so comprehensively. The study of cell wall structural diversity is also an important aspect of the industrial utilization of global polysaccharide bio-resources.

  7. Plant cell walls to ethanol.

    Science.gov (United States)

    Conversion of plant cell walls to ethanol constitutes generation 2 bioethanol production. The process consists of several steps: biomass selection/genetic modification, physiochemical pretreatment, enzymatic saccharification, fermentation, and separation. Ultimately, it is desired to combine as man...

  8. Chromosome aberrations in ataxia telangiectasia cells exposed to heavy ions

    Science.gov (United States)

    Kawata, T.; Cucinotta, F.; George, K.; Wu, H.; Shigematsu, N.; Furusawa, Y.; Uno, T.; Isobe, K.; Ito, H.

    Understanding of biological effects of heavy ions is important to assess healt h risk in space. One of the most important issues may be to take into account individual susceptibility. Ataxia telangiectasia (A-T) cells are known to exhibit abnormal responses to radiations but the mechanism of hyper radiosensitivity of A-T still remains unknown. We report chromosome aberrations in normal human fibroblasts and AT fibroblasts exposed to low- and high-LET radiations. A chemical-induced premature chromosome condensation (PCC) technique combined with chromosome- painting technique was applied to score chromosome aberrations in G2/M-phase cells. Following gamma irradiation, GM02052 cells were approximately 5 times more sensitive to g-rays than AG1522 cells. GM02052 cells had a much higher frequency of deletions and misrejoining than AG1522 cells. When the frequency of complex type aberrations was compared, GM02052 cells showed more than 10 times higher frequency than AG1522 cells. The results will be compared with those obtained from high-LET irradiations.

  9. A study of chromosomal aberrations in amniotic fluid cell cultures.

    Science.gov (United States)

    Wolstenholme, J; Crocker, M; Jonasson, J

    1988-06-01

    This paper represents the analysis of 1916 routine amniotic fluid specimens harvested by an in situ fixation technique in a prospective study with regard to cultural chromosome anomalies. Excluding constitutional abnormalities, 2.9 per cent of 19,432 cells analysed showed some form of chromosome anomaly, terminal deletions (57 per cent) and chromatid/chromosome breaks and gaps (18 per cent) being the most frequent, followed by interchange aberrations (13 per cent) and trisomy (5 per cent). No case was found of more than one colony from the same culture showing the same anomaly without it being present in other cultures from the same fluid. The wholly abnormal colonies had a surplus of trisomies and from the mathematical considerations presented one may infer that these are likely to reflect the presence of abnormal cells in the amniotic fluid. Partly abnormal colonies appeared at a frequency that would correspond to virtual absence of selection against chromosomally abnormal cells when cultured in vitro. The aberrations found were similar to those seen as single cell anomalies, except for chromatid breaks and exchanges. The data suggest a basic preferential induction of trisomy for chromosomes 2, 18, 21, and the Y-chromosome. Structural aberrations showed a marked clustering of breakpoints around the centromeres. The frequency of mutant cells was low (1.4 X 10(-3)) before culture was initiated. At harvest, the frequency of abnormal cells was much higher (3 X 10(-2)) corresponding to 3 X 10(-3) mutations per cell per generation accumulating over approximately ten generations in vitro.

  10. Chapter 3 Cell Wall Chemistry

    Science.gov (United States)

    Roger M. Rowell; Roger Pettersen; Mandla A. Tshabalala

    2012-01-01

    Wood is best defined as a three-dimensional biopolymer composite composed of an interconnected network of cellulose, hemicelluloses and lignin with minor amounts of extractives, and inorganics. The major chemical component of a living tree is water, but on a dry weight basis, all wood cell walls consist mainly of sugar-based polymers (carbohydrates, 65-75%) that are...

  11. Investigation of an Aberrant Cell Voltage During the Filling of a Large Lithium Thionyl Chloride Cell

    Science.gov (United States)

    Thaller, Lawrence H.; Quinzio, Michael V.

    1997-01-01

    The investigation of an aberrant cell voltage during the filling of a large lithium thionyl chloride cell summary is at: an aberrant voltage trace was noted during the review of cell filling data; incident was traced to an interruption during filling; experimentation suggested oxidizable sites within the carbon electrode were responsible for the drop in voltage; the voltage anomaly could be reproduced by interrupting the filling of similar cells; and anomalous voltage dip was not due to a short.

  12. Cells, walls, and endless forms.

    Science.gov (United States)

    Monniaux, Marie; Hay, Angela

    2016-12-01

    A key question in biology is how the endless diversity of forms found in nature evolved. Understanding the cellular basis of this diversity has been aided by advances in non-model experimental systems, quantitative image analysis tools, and modeling approaches. Recent work in plants highlights the importance of cell wall and cuticle modifications for the emergence of diverse forms and functions. For example, explosive seed dispersal in Cardamine hirsuta depends on the asymmetric localization of lignified cell wall thickenings in the fruit valve. Similarly, the iridescence of Hibiscus trionum petals relies on regular striations formed by cuticular folds. Moreover, NAC transcription factors regulate the differentiation of lignified xylem vessels but also the water-conducting cells of moss that lack a lignified secondary cell wall, pointing to the origin of vascular systems. Other novel forms are associated with modified cell growth patterns, including oriented cell expansion or division, found in the long petal spurs of Aquilegia flowers, and the Sarracenia purpurea pitcher leaf, respectively. Another good example is the regulation of dissected leaf shape in C. hirsuta via local growth repression, controlled by the REDUCED COMPLEXITY HD-ZIP class I transcription factor. These studies in non-model species often reveal as much about fundamental processes of development as they do about the evolution of form. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. An enzymatic approach to cell wall structure

    African Journals Online (AJOL)

    afsonderlik. Keywords: Ruminococcus a/bus, alfalfa cell walls, cellulose, hemicellulose, enzymic digestion. Introduction. The aim of the research is to provide more specific infor- mation on the chemical linkages in plant cell wall material. The procedure is (l) to determine which constituents of plant cell walls are digested by a ...

  14. Prompt cytomolecular identification of chromosome aberration in irradiated blood cells

    Directory of Open Access Journals (Sweden)

    Seyed Akbar Moosavi

    2017-02-01

    Full Text Available Background: understanding the genomic alteration induced by ionizing radiation still remains to be a methodological challenge in genetic field. The energy released from this type of radiation can potentially causes structural and numerical alterations in lymphocytes, which in turn converts them into abnormal tumor cells. Chromosomal abnormalities associated with specific type of hematological malignancies are determinant factors in evaluation of radiation dose and its potential in harming the body. None the less early detection of chromosomal aberration (CA is crucial in prognosis and selection of therapy for the people exposed to irradiations. The aim of this study was to explore a swift and accurate genetic test that identifies CAs in radiologist exposed to X-rays. In addition synergistic effect of other clastogens in irradiated workers was also evaluated. Material and methods: thirty four heparinized blood samples were obtained from radiology workers exposed to X-rays. Blood samples were cultured in RPMI 1640 and F-10 Medias with and without PHA stimulation. Lymphocytes were harvested, separated and arrested at metaphase and their chromosomes were analyzed by solid and G-Banding techniques. Lymphocytic CA was also analyzed through whole chromosome painting FISH. Results: of the 37 blood sample from workers, 60% had various structural aberrations in which both the frequency and type of CAs were intensified among tobacco smokers. Conclusion: the results did not show any significant differences between the genders but other carcinogen like smoking can significantly increases the rate of CAs

  15. UV-induced chromatid aberrations in two cell linear of Chinese hamster with different repair activity

    International Nuclear Information System (INIS)

    Ikushima, Takaji

    1978-01-01

    To elucidate the mechanism of chromosomal aberration formation, the yield and type of chromosomal aberrations induced by ultraviolet light (UV) irradiation were compared in cultured Chinese hamster cells with different repair activity. After irradiation of low fluences of UV, chromatid aberrations were produced more frequently in one cell line with impaired repair activity, B14FAF than the other showing normal DNA repair replication, CHO. There were no difference in the spectrum of the aberration types between the two. The results imply that impaired excision repair of UV-induced pyrimidine dimers or other photoproducts results in higher yield of chromosomal aberrations, and suggest the involvement of DNA repair processes in chromosomal aberration formation. (author)

  16. How do plant cell walls extend?

    Science.gov (United States)

    Cosgrove, D. J.

    1993-01-01

    This article briefly summarizes recent work that identifies the biophysical and biochemical processes that give rise to the extension of plant cell walls. I begin with the biophysical notion of stress relaxation of the wall and follow with recent studies of wall enzymes thought to catalyze wall extension and relaxation. Readers should refer to detailed reviews for more comprehensive discussion of earlier literature (Taiz, 1984; Carpita and Gibeaut, 1993; Cosgrove, 1993).

  17. Cell Wall Remodeling Enzymes Modulate Fungal Cell Wall Elasticity and Osmotic Stress Resistance.

    Science.gov (United States)

    Ene, Iuliana V; Walker, Louise A; Schiavone, Marion; Lee, Keunsook K; Martin-Yken, Hélène; Dague, Etienne; Gow, Neil A R; Munro, Carol A; Brown, Alistair J P

    2015-07-28

    The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Cek1) signaling pathways. These mitogen-activated protein kinase (MAPK) pathways modulate cell wall gene expression, leading to the construction of a new, modified cell wall. We show that the cell wall is not rigid but elastic, displaying rapid structural realignments that impact survival following osmotic shock. Lactate-grown Candida albicans cells are more resistant to hyperosmotic shock than glucose-grown cells. We show that this elevated resistance is not dependent on Hog1 or Mkc1 signaling and that most cell death occurs within 10 min of osmotic shock. Sudden decreases in cell volume drive rapid increases in cell wall thickness. The elevated stress resistance of lactate-grown cells correlates with reduced cell wall elasticity, reflected in slower changes in cell volume following hyperosmotic shock. The cell wall elasticity of lactate-grown cells is increased by a triple mutation that inactivates the Crh family of cell wall cross-linking enzymes, leading to increased sensitivity to hyperosmotic shock. Overexpressing Crh family members in glucose-grown cells reduces cell wall elasticity, providing partial protection against hyperosmotic shock. These changes correlate with structural realignment of the cell wall and with the ability of cells to withstand osmotic shock. The C. albicans cell wall is the first line of defense against external insults, the site of immune recognition by the host, and an attractive target for antifungal therapy. Its tensile strength is conferred by

  18. Induction of chromosome aberrations in two lines of cultured cells using different types of radiation

    International Nuclear Information System (INIS)

    Zoetelief, J.; Dingjan-Hirschi, E.S.; Hasper, J.; Janse, H.C.; Barendsen, G.W.

    The induction of chromosome aberrations has been investigated in two lines of cultured cells for different types of radiation. The obtained results are compared with information on induction of cell reproductive death and malignant transformation. (Auth.)

  19. Glycoprotein component of plant cell walls

    International Nuclear Information System (INIS)

    Cooper, J.B.; Chen, J.A.; Varner, J.E.

    1984-01-01

    The primary wall surrounding most dicotyledonous plant cells contains a hydroxyproline-rich glycoprotein (HRGP) component named extensin. A small group of glycopeptides solubilized from isolated cell walls by proteolysis contained a repeated pentapeptide glycosylated by tri- and tetraarabinosides linked to hydroxyproline and, by galactose, linked to serine. Recently, two complementary approaches to this problem have provided results which greatly increase the understanding of wall extensin. In this paper the authors describe what is known about the structure of soluble extensin secreted into the walls of the carrot root cells

  20. [The cell wall of Coelastrum (Chlorophycees)].

    Science.gov (United States)

    Reymond, O

    1975-01-01

    The cell wall of Coelastrum is usually composed of three layers. The outermost layer was studied most extensively. It consists of erect tubules which often bear long bristles whose function may be to stabilize the algae in its enviroment. The cell wall can modify its morphology according to the enviroment.

  1. Reinitiation of cell wall growth after threonine starvation of Streptococcus faecalis.

    Science.gov (United States)

    Higgins, M L; Pooley, H M; Shockman, G D

    1971-03-01

    Cultures of Streptococcus faecalis ATCC 9790 were starved of threonine for 10 hr and then allowed to reinitiate growth in a fresh complete medium. On regrowth, culture turbidity began to increase within 10 min, but the ability of cells to autolyze did not begin to increase until after 30 min. Ultrastructural studies of regrowth of the initially thick-walled cells showed, at about 30 min, centripetal linear extension of new thin cross wall. This was followed, at about 40 min, by a notching, splitting, and peeling apart of the base of the cross wall. After this, extension of new thin peripheral wall from the nascent cross wall appeared to push old thick wall toward the poles. After the first cell division, asymmetric cells with one initial generation thick-walled pole and one second generation thin-walled pole were seen. After two divisions, thick-walled hemispheres were still seen, suggesting conservation of old wall during this time. A small fraction of the initial cell population exhibited aberrations and difficulties in reinitiating linear wall extension and were useful in the establishment of a model for the reinitiation of linear wall extension.

  2. Spontaneous chromosome aberrations in cancer cells. Evidence of existence of hidden genetic lesions in genetic structures

    International Nuclear Information System (INIS)

    Poryadkova-Luchnik, N.A.; Kuz'mina, E.G.

    1996-01-01

    Chromosome aberrations spontaneously observed in cancer cells were quantitively studied under the effect of non-mutagenic (suboptimal temperature, low content of propilgallate and caffeine) and mutagenic (ionizing radiation) factors. Human larynx cancer cells during several years or gamma-irradiation were used to carry out experiments. The experiments linked with cloning of the initial population and investigation into chromosome aberrations in 22 clones demonstrated persuasively the occurrence of latent genetic lesions in cancer cells

  3. Polyphosphorylated fungal cell wall glycopeptides

    Energy Technology Data Exchange (ETDEWEB)

    Bonetti, S.J.; Black, B.; Gander, J.E.

    1987-05-01

    Penicillium charlesii secretes a 65 kDa peptidophosphogalactomannan (pPGM) containing 10 phosphodiester residues and 10 galactofuranosyl-containing galactin chains attached to a linear mannan; the polysaccharides is attached to a 3 kDa seryl- and threonyl-rich peptide. The authors have now isolated and partially characterized a form of pPGM released from mycelia of P. charlesii treated at 50/sup 0/C for 15, 30, 60 or 120 min. Two- to 3-fold more pPGM was released by heat treatment than is secreted. Crude pPGM, released by heat, was fractionated on DE-52 and was fractionated into two major fractions on the basis of its difference in negative charge. /sup 1/H-decoupled /sup 13/C NMR spectroscopy of these two fractions provided spectra very similar to that of secreted pPGM previously reported from this laboratory. /sup 1/H-decoupled /sup 31/P NMR showed major signals at 1.47, and 0.22 ppm and minor signals at 1.32, 1.15, 1.00, 0.91 and 0.76 ppm. These signals are upfield from phosphomonoesters and are in the region observed for (6-O-phosphorylcholine)- and (6-O-phosphorylethanolamine)-..cap alpha..-D-mannopyranosyl residues which are 0.22 and 0.90 ppm, respectively. These polymers contain 30 phosphodiester residues per molecule of 70 kDa mass compared with 10 phosphodiesters in secreted pPGM. Acid phosphatase and alkaline protease were the only lytic enzymes released by heat treatment. The evidence suggests that much of the pPGM is derived from cell walls; and that the polysaccharide is highly phosphorylated.

  4. Cell wall, cytoskeleton, and cell expansion in higher plants.

    Science.gov (United States)

    Bashline, Logan; Lei, Lei; Li, Shundai; Gu, Ying

    2014-04-01

    To accommodate two seemingly contradictory biological roles in plant physiology, providing both the rigid structural support of plant cells and the adjustable elasticity needed for cell expansion, the composition of the plant cell wall has evolved to become an intricate network of cellulosic, hemicellulosic, and pectic polysaccharides and protein. Due to its complexity, many aspects of the cell wall influence plant cell expansion, and many new and insightful observations and technologies are forthcoming. The biosynthesis of cell wall polymers and the roles of the variety of proteins involved in polysaccharide synthesis continue to be characterized. The interactions within the cell wall polymer network and the modification of these interactions provide insight into how the plant cell wall provides its dual function. The complex cell wall architecture is controlled and organized in part by the dynamic intracellular cytoskeleton and by diverse trafficking pathways of the cell wall polymers and cell wall-related machinery. Meanwhile, the cell wall is continually influenced by hormonal and integrity sensing stimuli that are perceived by the cell. These many processes cooperate to construct, maintain, and manipulate the intricate plant cell wall--an essential structure for the sustaining of the plant stature, growth, and life.

  5. Synthesis of plant cell wall oligosaccharides

    OpenAIRE

    Clausen, Mads Hartvig

    2017-01-01

    Plant cell walls are structurally complex and contain a large number of diverse carbohydrate polymers. These plant fibers are a highly valuable bio-resource and the focus of food, energy and health research. We are interested in studying the interplay of plant cell wall carbohydrates with proteins such as enzymes, cell surface lectins, and antibodies. However, detailed molecular level investigations of such interactions are hampered by the heterogeneity and diversity of the polymers of intere...

  6. Visualizing chemical functionality in plant cell walls

    OpenAIRE

    Zeng, Yining; Himmel, Michael E.; Ding, Shi-You

    2017-01-01

    Understanding plant cell wall cross-linking chemistry and polymeric architecture is key to the efficient utilization of biomass in all prospects from rational genetic modification to downstream chemical and biological conversion to produce fuels and value chemicals. In fact, the bulk properties of cell wall recalcitrance are collectively determined by its chemical features over a wide range of length scales from tissue, cellular to polymeric architectures. Microscopic visualization of cell wa...

  7. Molecular regulation of plant cell wall extensibility

    Science.gov (United States)

    Cosgrove, D. J.

    1998-01-01

    Gravity responses in plants often involve spatial and temporal changes in cell growth, which is regulated primarily by controlling the ability of the cell wall to extend. The wall is thought to be a cellulose-hemicellulose network embedded in a hydrated matrix of complex polysaccharides and a small amount of structural protein. The wall extends by a form of polymer creep, which is mediated by expansins, a novel group of wall-loosening proteins. Expansins were discovered during a molecular dissection of the "acid growth" behavior of cell walls. Expansin alters the rheology of plant walls in profound ways, yet its molecular mechanism of action is still uncertain. It lacks detectable hydrolytic activity against the major components of the wall, but it is able to disrupt noncovalent adhesion between wall polysaccharides. The discovery of a second family of expansins (beta-expansins) sheds light on the biological role of a major group of pollen allergens and implies that expansins have evolved for diverse developmental functions. Finally, the contribution of other processes to wall extensibility is briefly summarized.

  8. 2003 Plant Cell Walls Gordon Conference

    Energy Technology Data Exchange (ETDEWEB)

    Daniel J. Cosgrove

    2004-09-21

    This conference will address recent progress in many aspects of cell wall biology. Molecular, genetic, and genomic approaches are yielding major advances in our understanding of the composition, synthesis, and architecture of plant cell walls and their dynamics during growth, and are identifying the genes that encode the machinery needed to make their biogenesis possible. This meeting will bring together international scientists from academia, industry and government labs to share the latest breakthroughs and perspectives on polysaccharide biosynthesis, wood formation, wall modification, expansion and interaction with other organisms, and genomic & evolutionary analyses of wall-related genes, as well as to discuss recent ''nanotechnological'' advances that take wall analysis to the level of a single cell.

  9. Refractive index of plant cell walls

    Science.gov (United States)

    Gausman, H. W.; Allen, W. A.; Escobar, D. E.

    1974-01-01

    Air was replaced with media of higher refractive indices by vacuum infiltration in leaves of cucumber, blackeye pea, tomato, and string bean plants, and reflectance of noninfiltrated and infiltrated leaves was spectrophotometrically measured. Infiltrated leaves reflected less light than noninfiltrated leaves over the 500-2500-nm wavelength interval because cell wall-air interfaces were partly eliminated. Minimal reflectance should occur when the average refractive index of plant cell walls was matched by the infiltrating fluid. Although refractive indices that resulted in minimal reflectance differed among the four plant genera, an average value of 1.425 approximates the refractive index of plant cell walls for the four plant genera.

  10. Cell Wall Diversity in Forage Maize

    NARCIS (Netherlands)

    Torres, A.F.; Noordam-Boot, C.M.M.; Dolstra, Oene; Weijde, van der Tim; Combes, Eliette; Dufour, Philippe; Vlaswinkel, Louis; Visser, R.G.F.; Trindade, L.M.

    2015-01-01

    Genetic studies are ideal platforms for assessing the extent of genetic diversity, inferring the genetic architecture, and evaluating complex trait interrelations for cell wall compositional and bioconversion traits relevant to bioenergy applications. Through the characterization of a forage

  11. Immersion Refractometry of Isolated Bacterial Cell Walls

    Science.gov (United States)

    Marquis, Robert E.

    1973-01-01

    Immersion-refractometric and light-scattering measurements were adapted to determinations of average refractive indices and physical compactness of isolated bacterial cell walls. The structures were immersed in solutions containing various concentrations of polymer molecules that cannot penetrate into wall pores, and then an estimate was made of the polymer concentration or the refractive index of the polymer solution in which light scattering was reduced to zero. Because each wall preparation was heterogeneous, the refractive index of the medium for zero light scattering had to be estimated by extrapolation. Refractive indices for walls suspended in bovine serum albumin solutions ranged from 1.348 for walls of the rod form of Arthrobacter crystallopoietes to 1.382 for walls of the teichoic acid deficient, 52A5 strain of Staphylococcus aureus. These indices were used to calculate approximate values for solids content per milliliter, and the calculated values agreed closely with those estimated from a knowledge of dextran-impermeable volumes per gram, dry weight, of the walls. When large molecules such as dextrans or serum albumin were used for immersion refractometry, the refractive indices obtained were for entire walls, including both wall polymers and wall water. When smaller molecules that can penetrate wall pores to various extents were used with Micrococcus lysodeikticus walls, the average, apparent refractive index of the structures increased as the molecular size of probing molecules was decreased. It was possible to obtain an estimate of 1.45 to 1.46 for the refractive index of wall polymers, predominantly peptidoglycans in this case, by extrapolating the curve for refractive index versus molecular radius to a value of 0.2 nm, the approximate radius of a water molecule. This relatively low value for polymer refractive index was interpreted as evidence in favor of the amorphous, elastic model of peptidoglycan structure and against the crystalline, rigid

  12. Hyperthermic radiosensitization of synchronous Chinese hamster cells: relationship between lethality and chromosomal aberrations

    International Nuclear Information System (INIS)

    Dewey, W.C.; Sapareto, S.A.; Betten, D.A.

    1978-01-01

    Synchronous Chinese hamster cells in vitro were obtained by mitotic selection. The cells were heated at 45.5 0 C for 4 min in mitosis, 11 min in G 1 , or 7 min in S sphase and then x-irradiated immediately thereafter. Colony survival from heat alone was 0.30 to 0.45, and the frequency of chromosomal aberrations induced by heat was 0.00, 0.14, or 0.97 for heat treatments during M, G 1 , or S, respectively. As shown previously, lethality from hyperthermia alone is due to chromosomal aberrations only when the cells are heated during S phase. The log survival (D 0 /sup approximately/ = 80 rad) and aberration frequency curves for cells irradiated during mitosis were linear, and the only effect of hyperthermia was to shift the curves in accord with the effect from heat alone. Thus, hyperthermia did not radiosensitize the mitotic cells. The cells irradiated in G 1 were more resistant (D 0 /sup approximately/ = 100 rad) than those irradiated in mitosis, and the survival and aberration frequency curves both had shoulders. The primary effect of hyperthermia was to greatly reduce the shoulders of the curves and to increase the slopes by about 23%. The cells irradiated in S were the most resistant (D 0 /sup approximately/ = 140 rad), and the survival and aberration frequency curves both had large shoulders. For both end points of lethality and chromosomal aberrations, heat selectively radiosensitized S-phase cells relative to G 1 cells by removing most of the shoulder and increasing the slope by about 45%. For cells treated in G 1 or S, the increase in radiosensitization following hyperthermia can be accounted for by an increase in the frequency of chromosomal aberrations

  13. Identification of pseudomurein cell wall binding domains.

    Science.gov (United States)

    Steenbakkers, Peter J M; Geerts, Wim J; Ayman-Oz, Nilgün A; Keltjens, Jan T

    2006-12-01

    Methanothermobacter thermautotrophicus is a methanogenic Gram-positive microorganism with a cell wall consisting of pseudomurein. Currently, no information is available on extracellular pseudomurein biology and so far only two prophage pseudomurein autolysins, PeiW and PeiP, have been reported. In this paper we show that PeiW and PeiP contain two different N-terminal pseudomurein cell wall binding domains. This finding was used to identify a novel domain, PB007923, on the M. thermautotrophicus genome present in 10 predicted open reading frames. Three homologues were identified in the Methanosphaera stadtmanae genome. Binding studies of fusion constructs of three separate PB007923 domains to green fluorescent protein revealed that it also constituted a cell wall binding domain. Both prophage domains and the PB007923 domain bound to the cell walls of Methanothermobacter species and fluorescence microscopy showed a preference for the septal region. Domain specificities were revealed by binding studies with other pseudomurein-containing archaea. Localized binding was observed for M. stadtmanae and Methanobrevibacter species, while others stained evenly. The identification of the first pseudomurein cell wall binding domains reveals the dynamics of the pseudomurein cell wall and provides marker proteins to study the extracellular pseudomurein biology of M. thermautotrophicus and of other pseudomurein-containing archaea.

  14. Plant cell wall polysaccharide analysis during cell elongation

    DEFF Research Database (Denmark)

    Guo, Xiaoyuan

    Plant cell walls are complex structures whose composition and architecture are important to various cellular activities. Plant cell elongation requires a high level of rearrangement of the cell wall polymers to enable cell expansion. However, the cell wall polysaccharides dynamics during plant cell...... elongation is poorly understood. This PhD project aims to elucidate the cell wall compositional and structural change during cell elongation by using Comprehensive Microarray Polymer Profiling (CoMPP), microscopic techniques and molecular modifications of cell wall polysaccharide. Developing cotton fibre......, pea and Arabidopsis thaliana were selected as research models to investigate different types of cell elongation, developmental elongation and tropism elongation. A set of comprehensive analysis covering 4 cotton species and 11 time points suggests that non-cellulosic polysaccharides contribute...

  15. Aberrant methylation of cell-free circulating DNA in plasma predicts poor outcome in diffuse large B cell lymphoma

    DEFF Research Database (Denmark)

    Sommer Kristensen, Lasse; Hansen, Jakob Werner; Kristensen, Søren Sommer

    2016-01-01

    III and IV. Multivariate analysis identified DAPK1 as an independent prognostic factor for OS with a hazard ratio of 8.9 (95 % CI 2.7-29.3, P circulating DNA at time of diagnosis, who became long-term survivors, lost the aberrant methylation after......BACKGROUND: The prognostic value of aberrant DNA methylation of cell-free circulating DNA in plasma has not previously been evaluated in diffuse large B cell lymphoma (DLBCL). The aim of this study was to investigate if aberrant promoter DNA methylation can be detected in plasma from DLBCL patients...... treatment initiation. Conversely, patients that maintained or regained aberrant DAPK1 methylation died soon thereafter. CONCLUSIONS: Aberrant promoter methylation of cell-free circulating DNA can be detected in plasma from DLBCL patients and hold promise as an easily accessible marker for evaluating...

  16. Identification of Novel Cell Wall Components

    Energy Technology Data Exchange (ETDEWEB)

    Michelle Momany

    2009-10-26

    Our DOE Biosciences-funded work focused on the fungal cell wall and morphogenesis. We are especially interested in how new cell wall material is targeted to appropriate areas for polar (asymmetric) growth. Polar growth is the only way that filamentous fungi explore the environment to find suitable substrates to degrade. Work funded by this grant has resulted in a total of twenty peer-reviewed publications. In work funded by this grant, we identified nine Aspergillus nidulans temperature-sensitive (ts) mutants that fail to send out a germ tube and show a swollen cell phenotype at restrictive temperature, the swo mutants. In other organisms, a swollen cell phenotype is often associated with misdirected growth or weakened cell walls. Our work shows that several of the A. nidulans swo mutants have defects in the establishment and maintenance of polarity. Cloning of several swo genes by complementation also showed that secondary modification of proteins seems is important in polarity. We also investigated cell wall biosynthesis and branching based on leads in literature from other organisms and found that branching and nuclear division are tied and that the cell wall reorganizes during development. In our most recent work we have focused on gene expression during the shift from isotropic to polar growth. Surprisingly we found that genes previously thought to be involved only in spore formation are important in early vegetative growth as well.

  17. Synthesis of plant cell wall oligosaccharides

    DEFF Research Database (Denmark)

    Clausen, Mads Hartvig

    Plant cell walls are structurally complex and contain a large number of diverse carbohydrate polymers. These plant fibers are a highly valuable bio-resource and the focus of food, energy and health research. We are interested in studying the interplay of plant cell wall carbohydrates with proteins...... for characterizing protein-carbohydrate binding. The presentation will highlight chemical syntheses of plant cell wall oligosaccharides from the group and provide examples from studies of their interactions with proteins....... such as enzymes, cell surface lectins, and antibodies. However, detailed molecular level investigations of such interactions are hampered by the heterogeneity and diversity of the polymers of interest. To circumvent this, we target well-defined oligosaccharides with representative structures that can be used...

  18. RBE of neutrons for induction of cell reproductive death and chromosome aberrations in three cell lines

    International Nuclear Information System (INIS)

    Zoetelief, J.; Kuijpers, W.C.; Baten-Wittwer, A.; Barendsen, G.W.

    1983-01-01

    The authors have compared the RBE values for induction of dicentrics and centric rings with those for cell inactivation and with the mean or effective quality factors (Q) recommended for radiation protection. The induction of cell reproductive death and chromosome aberrations has been investigated in plateau phase cultures of established lines of a rat rhabdomyosarcoma, a rat ureter carcinoma and Chinese hamster cells for single doses of 300 kV X-rays and 0.5, 4.2 and 15 MeV neutrons. The different cell lines show considerable variations in sensitivity and the RBE values obtained are presented in tabular form. The mean RBE values for the rat rhabdomyosarcoma cells are lower than those for the other two relatively resistant cell lines. Those for the Chinese hamster cells extrapolated to levels according to low doses of X-rays are in good agreement with the quoted Q values. (Auth./C.F.)

  19. Enzymatic Modification of Plant Cell Wall Polysaccharides

    DEFF Research Database (Denmark)

    Øbro, Jens; Hayashi, Takahisa; Mikkelsen, Jørn Dalgaard

    2011-01-01

    for sustainable processes that replace chemical treatments with white biotechnology. Plants can contribute significantly to this sustainable process by producing plant or microbialenzymes in planta that are necessary for plant cell wall modification or total degradation. This will give rise to superior food......Plant cell walls are intricate structures with remarkable properties, widely used in almost every aspect of our life. Cell walls consist largely of complex polysaccharides and there is often a need for chemical and biochemical processing before industrial use. There is an increasing demand...... fibres, hydrocolloids, paper,textile, animal feeds or biofuels. Classical microbial-based fermentation systems could in the future face serious competition from plant-based expression systems for enzyme production. Plant expressed enzymes can either be targeted to specific cellular compartments...

  20. Aberrant Presentation of Self-Lipids by Autoimmune B Cells Depletes Peripheral iNKT Cells

    Directory of Open Access Journals (Sweden)

    Andy Hee-Meng Tan

    2014-10-01

    Full Text Available Invariant natural killer T (iNKT cells provide cognate help via CD1d to lipid antigen-presenting B cells for antibody production, but whether B cells reciprocally regulate iNKT cells remains largely unexplored. Here, we found peripheral, but not thymic, iNKT cells to be numerically reduced in autoimmune mice lacking Fas specifically in B cells. The residual iNKT cells were antigenically overstimulated, had altered cytokine production, and manifested enhanced proliferation and apoptosis. B cell-specific ablation of CD1d ameliorated these iNKT defects, suggesting that inappropriate presentation of CD1d-restricted self-lipids by autoimmune B cell-depleted peripheral iNKT cells. CD1d+ autoimmune B cells have reduced α-galactosidase A expression and, as revealed by lipidomic profiling, altered lipidome with aberrant accumulation of certain self-lipids and reduction of others. These findings unveil a critical link between autoimmunity, B cell lipidome, and the maintenance of peripheral iNKT cells and highlight an essential homeostatic function of B cells beyond antibody production.

  1. Roles of membrane trafficking in plant cell wall dynamics

    Directory of Open Access Journals (Sweden)

    Kazuo eEbine

    2015-10-01

    Full Text Available The cell wall is one of the characteristic components of plant cells. The cell wall composition differs among cell types and is modified in response to various environmental conditions. To properly generate and modify the cell wall, many proteins are transported to the plasma membrane or extracellular space through membrane trafficking, which is one of the key protein transport mechanisms in eukaryotic cells. Given the diverse composition and functions of the cell wall in plants, the transport of the cell wall components and proteins that are involved in cell wall-related events could be specialized for each cell type, i.e., the machinery for cell wall biogenesis, modification, and maintenance could be transported via different trafficking pathways. In this review, we summarize the recent progress in the current understanding of the roles and mechanisms of membrane trafficking in plant cells and focus on the biogenesis and regulation of the cell wall.

  2. Cell killing and chromosomal aberration induced by heavy-ion beams in cultured human tumor cells

    International Nuclear Information System (INIS)

    Takakura, K.; Funada, A.; Mohri, M.; Lee, R.; Aoki, M.; Furusawa, Y.; Gotoh, E.

    2003-01-01

    Full text: To clarify the relation between cell death and chromosomal aberration in cultured human tumor cells irradaited with heavy-ion beams. The analyses were carried out on the basis of the linear energy transfer (LET) values of heavy ion beams as radiation source. Exponentially growing human tumor cells, Human Salivary Gland Tumor cells (HSG cells), were irradiated with various high energy heavy ions, such as 13 keV/micrometer carbon (C) ions as low LET charged particle radiation source, 120 keV/ micrometer carbon (C) ions and 440 keV/micrometer iron (Fe) ions as high LET charged particle radiation sources.The cell death was analysed by the colony formation method, and the chromosomal aberration and its repairing kinetics was analysed by prematurely chromosome condensation method (PCC method) using calyculin A. Chromatid-type breaks, isochromatid breaks and exchanges were scored for the samples from the cells keeping with various incubation time after irradiation. The LET dependence of the cell death was similar to that of the chromosome exchange formation after 12 hours incubation. A maximum peak was around 120 keV/micrometer. However it was not similar to the LET dependence of isochromatid breaks or chromatid breaks after 12 hours incubation. These results suggest that the exchanges formed in chromosome after irradiation should be one of essential causes to lead the cell death. The different quality of induced chromosome damage between high-LET and low-LET radiation was also shown. About 89 % and 88 % chromatid breaks induced by X rays and 13 keV/micrometer C ions were rejoined within 12 hours of post-irradiation, though only 71% and 58 % of chromatid breaks induced by 120 keV/micrometer C ions and 440 keV/micrometer Fe ions were rejoined within 12 hours of post-irradiation

  3. Microanalysis of Plant Cell Wall Polysaccharides

    NARCIS (Netherlands)

    Obel, N.; Erben, V.; Schwarz, T.; Kühnel, S.; Fodor, A.; Pauly, M.

    2009-01-01

    Oligosaccharide Mass Profiling (OLIMP) allows a fast and sensitive assessment of cell wall polymer structure when coupled with Matrix Assisted Laser Desorption Ionisation Time Of Flight Mass Spectrometry (MALDI-TOF MS). The short time required for sample preparation and analysis makes possible the

  4. Influence of DMSO on Carbon K ultrasoft X-rays induced chromosome aberrations in V79 Chinese hamster cells

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Adayapalam T., E-mail: natarajan@live.nl [University of Tuscia, Viterbo (Italy); Palitti, Fabrizio [University of Tuscia, Viterbo (Italy); Hill, Mark A. [CRUK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom); MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD (United Kingdom); Stevens, David L. [MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD (United Kingdom); Ahnstroem, Gunnar [Department of Microbiology and Genetic Toxicology, Stockholm University, Stockholm (Sweden)

    2010-09-10

    Ultrasoft X-rays have been shown to be very efficient in inducing chromosomal aberrations in mammalian cells. The present study was aimed to evaluate the modifying effects of DMSO (a potent scavenger of free radicals) on the frequencies of chromosome aberrations induced by soft X-rays. Confluent held G1 Chinese hamster cells (V79) were irradiated with Carbon K ultrasoft X-rays in the presence and absence of 1 M DMSO and frequencies of chromosome aberrations in the first division cells were determined. DMSO reduced the frequencies of exchange types of aberrations (dicentrics and centric rings) by a factor of 2.1-3.5. The results indicate that free radicals induced by ultrasoft X-rays contribute to a great extent to the induction of chromosome aberrations. The possible implications of these results in interpreting the mechanisms involved in the high efficiency of ultrasoft X-rays in the induction of chromosome aberrations are discussed.

  5. Aberrant tropoelastin secretion in MG-63 human osteosarcoma cells

    International Nuclear Information System (INIS)

    Curtiss, S.W.

    1989-01-01

    The secretion of newly synthesized tropoelastin, the soluble precursor of the extracellular matrix protein elastin, is not well understood. MG-63 human osteosarcoma cells were found by immunoblot analysis to synthesize 62 kD and 64 kD tropoelastins. Media from 63 cells labelled for five hours with [ 3 H]-valine contain no detectable tropoelastin, unlike media from other tropoelastin-synthesizing cells. Immunoblots of conditioned media and 1Ox-concentrated conditioned media left on the cells for six days also show an absence of tropoelastin from the cell media. No insoluble elastin is associated with the cell layer, as determined by amino acid analysis and electron microscopy of 18-21 day cell cultures. The absence of tropoelastin from the cell medium and elastin from the extracellular matrix indicates that MG63 cells do not secrete tropoelastin as expected, but accumulate it intracellularly. This accumulation is transient: immunoblots and immunofluorescence microscopy show that cells three days after passage have the highest steady-state levels of tropoelastin per cell, that day 8 cells contain lower but still significant amounts of tropoelastin, and that by day 22 tropoelastin is no longer present in the cell cultures. Cell density is a critical factor in the observed pattern of tropoelastin expression. Cells seeded at ten fold their usual initial density have high tropoelastin levels at one day after passage, sooner than cells seeded normally. Tropoelastin also disappears from high density-seeded cells more quickly and is no longer detectable at day 10. Lysosome-like vesicles containing membranous structures appear by immunoelectron microscopy to be the primary site of intracellular tropoelastin localization

  6. Cell wall heterogeneity in root development of Arabidopsis

    Directory of Open Access Journals (Sweden)

    Marc Somssich

    2016-08-01

    Full Text Available Plant cell walls provide stability and protection to plant cells. During growth and development the composition of cell walls changes, but provides enough strength to withstand the turgor of the cells. Hence, cell walls are highly flexible and diverse in nature. These characteristics are important during root growth, as plant roots consist of radial patterns of cells that have diverse functions and that are at different developmental stages along the growth axis. Young stem cell daughters undergo a series of rapid cell divisions, during which new cell walls are formed that are highly dynamic, and that support rapid anisotropic cell expansion. Once the cells have differentiated, the walls of specific cell types need to comply with and support different cell functions. For example, a newly formed root hair needs to be able to break through the surrounding soil, while endodermal cells modify their walls at distinct positions to form Casparian strips between them. Hence, the cell walls are modified and rebuilt while cells transit through different developmental stages. In addition, the cell walls of roots readjust to their environment to support growth and to maximize nutrient uptake. Many of these modifications are likely driven by different developmental and stress signalling pathways. However, our understanding of how such pathways affect cell wall modifications and what enzymes are involved remain largely unknown. In this review we aim to compile data linking cell wall content and re-modelling to developmental stages of root cells, and dissect how root cell walls respond to certain environmental changes.

  7. Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR

    OpenAIRE

    Romaniuk, Joseph A. H.; Cegelski, Lynette

    2015-01-01

    The ability to characterize bacterial cell-wall composition and structure is crucial to understanding the function of the bacterial cell wall, determining drug modes of action and developing new-generation therapeutics. Solid-state NMR has emerged as a powerful tool to quantify chemical composition and to map cell-wall architecture in bacteria and plants, even in the context of unperturbed intact whole cells. In this review, we discuss solid-state NMR approaches to define pe...

  8. Induction of chromosome aberrations in unirradiated chromatin after partial irradiation of a cell nucleus

    NARCIS (Netherlands)

    Ludwików, G.; Xiao, Yun; Hoebe, R. A.; Franken, N. A. P.; Darroudi, F.; Stap, J.; van Oven, C. H.; van Noorden, C. J. F.; Aten, J. A.

    2002-01-01

    Purpose: It is generally accepted that chromosome exchanges in irradiated cells the formed through interactions between separate DNA doable-strand breaks (DSB). Here we tested whether non-irradiated DNA participate; in the formation of chromosome aberrations wen complex DNA DSB are induced elsewhere

  9. The significance of PTEN and AKT aberrations in pediatric T-cell acute lymphoblastic leukemia

    NARCIS (Netherlands)

    L.C. Zuurbier (Linda); E.F. Petricoin (Emanuel F.); M.J. Vuerhard (Maartje); V. Calvert (V.); C. Kooi (Clarissa); J.G.C.A.M. Buijs-Gladdines (Jessica); W.K. Smits; E. Sonneveld (Edwin); A.J.P. Veerman (Anjo); W.A. Kamps (Willem); M.A. Horstmann (Martin); R. Pieters (Rob); J.P.P. Meijerink (Jules)

    2012-01-01

    textabstractBackground PI3K/AKT pathway mutations are found in T-cell acute lymphoblastic leukemia, but their overall impact and associations with other genetic aberrations is unknown. PTEN mutations have been proposed as secondary mutations that follow NOTCH1-activating mutations and cause cellular

  10. The significance of PTEN and AKT aberrations in pediatric T-cell acute lymphoblastic leukemia

    NARCIS (Netherlands)

    Zuurbier, Linda; Petricoin, Emanuel F.; Vuerhard, Maartje J.; Calvert, Valerie; Kooi, Clarissa; Buijs-Gladdines, Jessica G. C. A. M.; Smits, Willem K.; Sonneveld, Edwin; Veerman, Anjo J. P.; Kamps, Willem A.; Horstmann, Martin; Pieters, Rob; Meijerink, Jules P. P.

    Background PI3K/AKT pathway mutations are found in T-cell acute lymphoblastic leukemia, but their overall impact and associations with other genetic aberrations is unknown. PTEN mutations have been proposed as secondary mutations that follow NOTCH1-activating mutations and cause cellular resistance

  11. Element analysis of a cell wall using PIXE

    Science.gov (United States)

    Jahnke, Andreas; Shimmen, Teruo; Koyama-Ito, Hiroko; Yamazaki, Toshimitsu

    1981-03-01

    The elemental analysis of cell walls of internodal cells of Chara corallina, a fresh water alga, was carried out using PIXE and 28 MeV α-particles from a cyclotron. The cell wall was a suitable monitoring system for heavy metal ions in water. Special attention was paid to the ion specific differences during adsorption to the cell wall.

  12. Celery (Apium graveolens) parenchyma cell walls: cell walls with minimal xyloglucan.

    Science.gov (United States)

    Thimm, Julian C.; Burritt, David J.; Sims, Ian M.; Newman, Roger H.; Ducker, William A.; Melton, Laurence D.

    2002-10-01

    The primary walls of celery (Apium graveolens L.) parenchyma cells were isolated and their polysaccharide components characterized by glycosyl linkage analysis, cross-polarization magic-angle spinning solid-state 13C nuclear magnetic resonance (CP/MAS 13C NMR) and X-ray diffraction. Glycosyl linkage analysis showed that the cell walls consisted of mainly cellulose (43 mol%) and pectic polysaccharides (51 mol%), comprising rhamnogalacturonan (28 mol%), arabinan (12 mol%) and galactan (11 mol%). The amounts of xyloglucan (2 mol%) and xylan (2 mol%) detected in the cell walls were strikingly low. The small amount of xyloglucan present means that it cannot coat the cellulose microfibrils. Solid-state 13C NMR signals were consistent with the constituents identified by glycosyl linkage analysis and allowed the walls to be divided into three domains, based on the rigidity of the polymers. Cellulose (rigid) and rhamnogalacturonan (semi-mobile) polymers responded to the CP/MAS 13C NMR pulse sequence and were distinguished by differences in proton spin relaxation time constants. The arabinans, the most mobile polymers, responded to single-pulse excitation (SPE), but not CP/MAS 13C NMR. From solid-state 13C NMR of the cell walls the diameter of the crystalline cellulose microfibrils was determined to be approximately 3 nm while X-ray diffraction of the cell walls gave a value for the diameter of approximately 2 nm.

  13. Study of Cell Division Aberrations Induced by Some Silica Dusts in Mammalian Cells in Vitro.

    Science.gov (United States)

    Béna, F; Danière, M C; Terzetti, F; Poirot, O; Elias, Z

    2000-01-01

    Previously we observed that some crystalline and amorphous (diatomaceous earths) silicas (but not pyrogenic amorphous silica) induced morphological transformation of Syrian hamster embryo (SHE) cells. In order to explore the mechanisms of the silica-induced cell transformation, in this study we have examined the possibility that silica may cause genomic changes by interfering with the normal events of mitotic division. The SHE cells were exposed to transforming samples of Min-U-Sil 5 quartz and amorphous diatomite earth (DE) as well as to inactive amorphous synthetic Aerosil 0X50 at concentrations between 9 and 36 μg/cm(2) of culture slide. Effects on the mitotic spindle and on chromosome congression and segregation through the mitotic stages were concurrently examined by differential and indirect immunofluorescence stainings using anti-β-tubulin antibody. Min-U-Sil 5 and DE dusts induced a significant increase in the number of aberrant mitotic cells detected by differential staining. Increased frequencies of monopolar mitoses and scattered chromosomes as well as a small incidence of lagging chromosomes in DE-treated cells were observed. The immunostaining was more efficient in the detection of spindle disturbances. Min-U-Sil induced a significantly concentration-dependent increase of monopolar spindles. At the highest concentration, highly disorganized prophase spindles and prometaphase multipolars were observed. These damages caused a concentration-dependent decrease in metaphase to anaphase transition. DE-induced spindle aberrations did not reach significant levels over control, although increase in monopolar and multipolar spindles were recorded. Exposure to OX50 particles did not disrupt spindle integrity. To determine whether micronuclei (MN) arise from divisional abnormalities induced by the active samples, we performed in SHE and human bronchial epithelial cells kinetochore (K)-specific and centromere (C)-specific staining, respectively. A concentration

  14. Induction of chromosome aberrations and mitotic arrest by cytomegalovirus in human cells

    International Nuclear Information System (INIS)

    AbuBakar, S.; Au, W.W.; Legator, M.S.; Albrecht, T.

    1988-01-01

    Human cytomegalovirus (CMV) is potentially an effective but often overlooked genotoxic agent in humans. We report here evidence that indicates that infection by CMV can induce chromosome alterations and mitotic inhibition. The frequency of chromosome aberrations induced was dependent on the input multiplicity of infection (m.o.i.) for human lung fibroblasts (LU), but not for human peripheral blood lymphocytes (PBLs) when both cell types were infected at the GO phase of the cell cycle. The aberrations induced by CMV were mostly chromatid breaks and chromosome pulverizations that resembled prematurely condensed S-phase chromatin. Pulverized chromosomes were not observed in LU cells infected with virus stocks that had been rendered nonlytic by UV-irradiation at 24,000 ergs/mm2 or from infection of human lymphocytes. In LU cells infected with UV-irradiated CMV, the frequency of aberrations induced was inversely dependent on the extent of the exposure of the CMV stock to the UV-light. In permissive CMV infection of proliferating LU cells at 24 hr after subculture, a high percentage (greater than 40%) of the metaphase cells were arrested at their first metaphase and displayed severely condensed chromosomes when harvested 48 hr later. A significant increase (p less than 0.05) in the chromosome aberration frequency was also observed. Our study shows that CMV infection is genotoxic to host cells. The types and extent of damage are dependent on the viral genome expression and on the cell cycle stage of the cells at the time of infection. The possible mechanisms for induction of chromosome damage by CMV are discussed

  15. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotide...

  16. Alfalfa stem tissues: Cell wall deposition, composition, and degradability

    NARCIS (Netherlands)

    Jung, H.G.; Engels, F.M.

    2002-01-01

    Declining cell wall degradability of alfalfa (Medicago sativa L.) stems with maturation limits the nutritional value of alfalfa for ruminants. This study characterized changes in cell wall concentration, composition, and degradability by rumen microbes resulting from alfalfa stem tissue

  17. Chromosomal Aberrations in Normal and AT Cells Exposed to High Dose of Low Dose Rate Irradiation

    Science.gov (United States)

    Kawata, T.; Shigematsu, N.; Kawaguchi, O.; Liu, C.; Furusawa, Y.; Hirayama, R.; George, K.; Cucinotta, F.

    2011-01-01

    Ataxia telangiectasia (A-T) is a human autosomally recessive syndrome characterized by cerebellar ataxia, telangiectases, immune dysfunction, and genomic instability, and high rate of cancer incidence. A-T cell lines are abnormally sensitive to agents that induce DNA double strand breaks, including ionizing radiation. The diverse clinical features in individuals affected by A-T and the complex cellular phenotypes are all linked to the functional inactivation of a single gene (AT mutated). It is well known that cells deficient in ATM show increased yields of both simple and complex chromosomal aberrations after high-dose-rate irradiation, but, less is known on how cells respond to low-dose-rate irradiation. It has been shown that AT cells contain a large number of unrejoined breaks after both low-dose-rate irradiation and high-dose-rate irradiation, however sensitivity for chromosomal aberrations at low-dose-rate are less often studied. To study how AT cells respond to low-dose-rate irradiation, we exposed confluent normal and AT fibroblast cells to up to 3 Gy of gamma-irradiation at a dose rate of 0.5 Gy/day and analyzed chromosomal aberrations in G0 using fusion PCC (Premature Chromosomal Condensation) technique. Giemsa staining showed that 1 Gy induces around 0.36 unrejoined fragments per cell in normal cells and around 1.35 fragments in AT cells, whereas 3Gy induces around 0.65 fragments in normal cells and around 3.3 fragments in AT cells. This result indicates that AT cells can rejoin breaks less effectively in G0 phase of the cell cycle? compared to normal cells. We also analyzed chromosomal exchanges in normal and AT cells after exposure to 3 Gy of low-dose-rate rays using a combination of G0 PCC and FISH techniques. Misrejoining was detected in the AT cells only? When cells irradiated with 3 Gy were subcultured and G2 chromosomal aberrations were analyzed using calyculin-A induced PCC technique, the yield of unrejoined breaks decreased in both normal and AT

  18. Association Mapping of Cell Wall Synthesis Regulatory Genes and Cell Wall Quality in Switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Bartley, Laura [Univ. of Oklahoma, Norman, OK (United States). Dept. of Microbiology and Plant Biology; Wu, Y. [Oklahoma State Univ., Stillwater, OK (United States); Zhu, L. [Oklahoma State Univ., Stillwater, OK (United States); Brummer, E. C. [Noble Foundation, Ardmore, OK (United States); Saha, M. [Noble Foundation, Ardmore, OK (United States)

    2016-05-31

    Inefficient conversion of biomass to biofuels is one of the main barriers for biofuel production from such materials. Approximately half of polysaccharides in biomass remain unused by typical biochemical conversion methods. Conversion efficiency is influenced by the composition and structure of cell walls of biomass. Grasses such as wheat, maize, and rice, as well as dedicated perennial bioenergy crops, like switchgrass, make up ~55% of biomass that can be produced in the United States. Grass cell walls have a different composition and patterning compared with dicotyledonous plants, including the well-studied model plant, Arabidopsis. This project identified genetic determinants of cell wall composition in grasses using both naturally occurring genetic variation of switchgrass and gene network reconstruction and functional assays in rice. In addition, the project linked functional data in rice and other species to switchgrass improvement efforts through curation of the most abundant class of regulators in the switchgrass genome. Characterizing natural diversity of switchgrass for variation in cell wall composition and properties, also known as quality, provides an unbiased avenue for identifying biologically viable diversity in switchgrass cell walls. To characterizing natural diversity, this project generated cell wall composition and enzymatic deconstruction data for ~450 genotypes of the Switchgrass Southern Association Collection (SSAC), a diverse collection composed of 36 switchgrass accessions from the southern U.S. distribution of switchgrass. Comparing these data with other measures of cell wall quality for the same samples demonstrated the complementary nature of the diverse characterization platforms now being used for biomass characterization. Association of the composition data with ~3.2K single nucleotide variant markers identified six significant single nucleotide variant markers co-associated with digestibility and another compositional trait. These

  19. An enzymatic approach to cell wall structure | Hungate | South ...

    African Journals Online (AJOL)

    Ruminococcus albus was incubated with isolated alfalfa cell wall material for 72 h in batch culture. Cellulose in the cell walls was digested to a somewhat greater extent (88%) than were the fermentable sugars of the hemicellulose fraction (62- 76%). The digestibility of the total insoluble alfalfa cell wall, including lignin but ...

  20. Tools to Understand Structural Property Relationships for Wood Cell Walls

    Science.gov (United States)

    Joseph E. Jakes; Daniel J. Yelle; Charles R. Frihart

    2011-01-01

    Understanding structure-property relationships for wood cell walls has been hindered by the complex polymeric structures comprising these cell walls and the difficulty in assessing meaningful mechanical property measurements of individual cell walls. To help overcome these hindrances, we have developed two experimental methods: 1) two-dimensional solution state nuclear...

  1. Mechanical properties of plant cell walls probed by relaxation spectra

    DEFF Research Database (Denmark)

    Hansen, Steen Laugesen; Ray, Peter Martin; Karlsson, Anders Ola

    2011-01-01

    Transformants and mutants with altered cell wall composition are expected to display a biomechanical phenotype due to the structural role of the cell wall. It is often quite difficult, however, to distinguish the mechanical behavior of a mutant's or transformant's cell walls from that of the wild...

  2. Aberrant signaling pathways in medulloblastomas: a stem cell connection

    Directory of Open Access Journals (Sweden)

    Carolina Oliveira Rodini

    2010-12-01

    Full Text Available Medulloblastoma is a highly malignant primary tumor of the central nervous system. It represents the most frequent type of solid tumor and the leading cause of death related to cancer in early childhood. Current treatment includes surgery, chemotherapy and radiotherapy which may lead to severe cognitive impairment and secondary brain tumors. New perspectives for therapeutic development have emerged with the identification of stem-like cells displaying high tumorigenic potential and increased radio- and chemo-resistance in gliomas. Under the cancer stem cell hypothesis, transformation of neural stem cells and/or granular neuron progenitors of the cerebellum are though to be involved in medulloblastoma development. Dissecting the genetic and molecular alterations associated with this process should significantly impact both basic and applied cancer research. Based on cumulative evidences in the fields of genetics and molecular biology of medulloblastomas, we discuss the possible involvement of developmental signaling pathways as critical biochemical switches determining normal neurogenesis or tumorigenesis. From the clinical viewpoint, modulation of signaling pathways such as TGFβ, regulating neural stem cell proliferation and tumor development, might be attempted as an alternative strategy for future drug development aiming at more efficient therapies and improved clinical outcome of patients with pediatric brain cancers.

  3. Cell inactivation and chromosomal aberrations induced by X-rays and fast neutrons in cells of the Chinese hamster. 1

    International Nuclear Information System (INIS)

    Tolkendorf, E.

    1979-01-01

    Asynchronously grown cultures of Chinese hamster cells V79-4 were irradiated in suspension with 180 kV X-rays and fast neutrons (average energy of 6.2 MeV). The damage was assessed by measuring cell survival and frequencies of chromosome aberrations in the first post-irradiation metaphases. The experimental data for survival and chromosome aberrations were fitted by computer programmes. From the fitted curves the relative biological effectiveness (RBE) of fast neutrons was calculated. The RBE shows a similar dose dependence for killed and aberrant cells. The RBE decreases with increasing dose and amounts to approximately 5 for both effects for small neutron doses. The highest RBE is found for asymmetrical chromosomal exchanges and is dependent on the neutron dose, too. However, for isochromatid deletions the RBE is dose independent with a value of 3.6. (author)

  4. Monoclonal antibodies against plant cell wall polysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Hahn, M.G.; Bucheli, E.; Darvill, A.; Albersheim, P. (Univ. of Georgia, Athens (USA))

    1989-04-01

    Monoclonal antibodies (McAbs) are useful tools to probe the structure of plant cell wall polysaccharides and to localize these polysaccharides in plant cells and tissues. Murine McAbs were generated against the pectic polysaccharide, rhamnogalacturonan I (RG-I), isolated from suspension-cultured sycamore cells. The McAbs that were obtained were grouped into three classes based upon their reactivities with a variety of plant polysaccharides and membrane glycoproteins. Eleven McAbs (Class I) recognize epitope(s) that appear to be immunodominant and are found in RG-I from sycamore and maize, citrus pectin, polygalacturonic acid, and membrane glycoproteins from suspension-cultured cells of sycamore, maize, tobacco, parsley, and soybean. A second group of five McAbs (Class II) recognize epitope(s) present in sycamore RG-I, but do not bind to any of the other polysaccharides or glycoproteins recognized by Class I. Lastly, one McAb (Class III) reacts with sycamore RG-I, sycamore and tamarind xyloglucan, and sycamore and rice glucuronoarabinoxylan, but does not bind to maize RG-I, polygalacturonic acid or the plant membrane glycoproteins recognized by Class I. McAbs in Classes II and III are likely to be useful in studies of the structure, biosynthesis and localization of plant cell wall polysaccharides.

  5. The cell wall: a carbohydrate armour for the fungal cell.

    Science.gov (United States)

    Latgé, Jean-Paul

    2007-10-01

    The cell wall is composed of a polysaccharide-based three-dimensional network. Considered for a long time as an inert exoskeleton, the cell wall is now seen as a dynamic structure that is continuously changing as a result of the modification of culture conditions and environmental stresses. Although the cell wall composition varies among fungal species, chemogenomic comparative analysis have led to a better understanding of the genes and mechanisms involved in the construction of the common central core composed of branched beta1,3 glucan-chitin. Because of its essential biological role, unique biochemistry and structural organization and the absence in mammalian cells of most of its constitutive components, the cell wall is an attractive target for the development of new antifungal agents. Genomic as well as drug studies have shown that the death of the fungus can result from inhibition of cell wall polysaccharide synthases. To date, only beta1,3 glucan synthase inhibitors have been launched clinically and many more targets remain to be explored.

  6. Fermentation of the endosperm cell walls of monocotyledon and dicotyledon plant species: The relationship between cell wall characteristics and fermentability

    NARCIS (Netherlands)

    Laar, van H.; Tamminga, S.; Williams, B.A.; Verstegen, M.W.A.

    2000-01-01

    Cell walls from the endosperm of four monocotyledons (maize, wheat, rye, and rice) and four dicotyledons (soya bean, lupin, faba bean, and pea) seeds were studied to relate cell wall composition and structure with fermentation characteristics. Cell wall material was isolated from the endosperm of

  7. Chromosomal Aberrations in DNA Repair Defective Cell Lines: Comparisons of Dose Rate and Radiation Quality

    Science.gov (United States)

    George, K. A.; Hada, M.; Patel, Z.; Huff, J.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Chromosome aberration yields were assessed in DNA double-strand break repair (DSB) deficient cells after acute doses of gamma-rays or high-LET iron nuclei, or low dose-rate (0.018 Gy/hr) gamma-rays. We studied several cell lines including fibroblasts deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase, DNA-PK activity. Chromosomes were analyzed using the fluorescence in-situ hybridization (FISH) chromosome painting method in cells at the first division post-irradiation and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma radiation induced higher yields of both simple and complex exchanges in the DSB repair defective cells than in the normal cells. The quadratic dose-response terms for both chromosome exchange types were significantly higher for the ATM and NBS defective lines than for normal fibroblasts. However, the linear dose-response term was significantly higher only for simple exchanges in the NBS cells. Large increases in the quadratic dose response terms indicate the important roles of ATM and NBS in chromatin modifications that facilitate correct DSB repair and minimize aberration formation. Differences in the response of AT and NBS deficient cells at lower doses suggests important questions about the applicability of observations of radiation sensitivity at high dose to low dose exposures. For all iron nuclei irradiated cells, regression models preferred purely linear and quadratic dose responses for simple and complex exchanges, respectively. All the DNA repair defective cell lines had lower Relative biological effectiveness (RBE) values than normal cells, the lowest being for the DNA-PK-deficient cells, which was near unity. To further

  8. High resolution DNA flow cytometry of boar sperm cells in identification of boars carrying cytogenetic aberrations

    DEFF Research Database (Denmark)

    Larsen, Jacob; Christensen, Knud; Larsen, Jørgen K

    2004-01-01

    The cytogenetic quality of boars used for breeding determines the litter outcome and thus has large economical consequences. Traditionally, quality controls based on the examination of simple karyograms are time consuming and sometimes give uncertain results. As an alternative, the use of high......-resolution DNA flow cytometry on DAPI-stained sperm cell nuclei (CV cytogenetic quality of boars. By analyzing a series of 25 animals judged normal by their fertility statistics and a series of seven animals with known reciprocal translocations, a model...... for identifying sperm cells from cytogenetically aberrant animals was proposed. This model was applied to a series of 50 uncharacterized animals. The model successfully identified a mosaic or chimaeric carrier of an aberrant X chromosome. However, implementation of this technique for screening purposes would...

  9. Plant cell wall signalling and receptor-like kinases.

    Science.gov (United States)

    Wolf, Sebastian

    2017-02-15

    Communication between the extracellular matrix and the cell interior is essential for all organisms as intrinsic and extrinsic cues have to be integrated to co-ordinate development, growth, and behaviour. This applies in particular to plants, the growth and shape of which is governed by deposition and remodelling of the cell wall, a rigid, yet dynamic, extracellular network. It is thus generally assumed that cell wall surveillance pathways exist to monitor the state of the wall and, if needed, elicit compensatory responses such as altered expression of cell wall remodelling and biosynthesis genes. Here, I highlight recent advances in the field of cell wall signalling in plants, with emphasis on the role of plasma membrane receptor-like kinase complexes. In addition, possible roles for cell wall-mediated signalling beyond the maintenance of cell wall integrity are discussed. © 2017 The Author(s); published by Portland Press Limited on behalf of the Biochemical Society.

  10. RBE of Energetic Iron Ions for the Induction of Early and Late Chromosome Aberrations in Different Cell Types

    Science.gov (United States)

    Zhang, Ye; Yeshitla, Samrawit; Hada, Megumi; Kadhim, Munira; Wilson, Bobby; Wu, Honglu

    2015-01-01

    Numerous published studies have reported the Relative Biological Effectiveness (RBE) values for chromosome aberrations induced by charged particles of different LET. The RBE for chromosome aberrations in human lymphocytes exposed ex vivo has been suggested to show a similar relationship as the quality factor for cancer induction. Therefore, increased chromosome aberrations in the astronauts' white blood cells post long-duration missions are used to determine the biological doses from exposures to space radiation. However, the RBE value is known to be very different for different types of cancer. Previously, we reported that, even though the RBE for initial chromosome damages was high in human lymphocytes exposed to Fe ions, the RBE was significantly reduced after multiple cell divisions post irradiation. To test the hypothesis that RBE values for chromosome aberrations are cell type dependent, and different between early and late damages, we exposed human lymphocytes ex vivo, and human mammary epithelial cells in vitro to various charged particles. Chromosome aberrations were quantified using the samples collected at first mitosis post irradiation for initial damages, and the samples collected after multiple generations for the remaining or late arising aberrations. Results of the study suggested that the effectiveness of high-LET charged particles for late chromosome aberrations may be cell type dependent, even though the RBE values are similar for early damages.

  11. Plant and algal cell walls: diversity and functionality.

    Science.gov (United States)

    Popper, Zoë A; Ralet, Marie-Christine; Domozych, David S

    2014-10-01

    Although plants and many algae (e.g. the Phaeophyceae, brown, and Rhodophyceae, red) are only very distantly related they are united in their possession of carbohydrate-rich cell walls, which are of integral importance being involved in many physiological processes. Furthermore,wall components have applications within food, fuel, pharmaceuticals, fibres (e.g. for textiles and paper) and building materials and have long been an active topic of research. As shown in the 27 papers in this Special Issue, as the major deposit of photosynthetically fixed carbon, and therefore energy investment, cell walls are of undisputed importance to the organisms that possess them, the photosynthetic eukaryotes ( plants and algae). The complexities of cell wall components along with their interactions with the biotic and abiotic environment are becoming increasingly revealed. The importance of plant and algal cell walls and their individual components to the function and survival of the organism, and for a number of industrial applications, are illustrated by the breadth of topics covered in this issue, which includes papers concentrating on various plants and algae, developmental stages, organs, cell wall components, and techniques. Although we acknowledge that there are many alternative ways in which the papers could be categorized (and many would fit within several topics), we have organized them as follows: (1) cell wall biosynthesis and remodelling, (2) cell wall diversity, and (3) application of new technologies to cell walls. Finally, we will consider future directions within plant cell wall research. Expansion of the industrial uses of cell walls and potentially novel uses of cell wall components are both avenues likely to direct future research activities. Fundamentally, it is the continued progression from characterization (structure, metabolism, properties and localization) of individual cell wall components through to defining their roles in almost every aspect of plant

  12. Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells

    International Nuclear Information System (INIS)

    Kim, Jung-Ah; Im, Kyong Ok; Park, Si Nae; Kwon, Ji Seok; Kim, Seon Young; Oh, Keunhee; Lee, Dong-Sup; Kim, Min Kyung; Kim, Seong Who; Jang, Mi; Lee, Gene; Oh, Yeon-Mok; Lee, Sang Do; Lee, Dong Soon

    2015-01-01

    Highlights: • We evaluated cytogenetic aberrations of MSC during culture using G-banding and FISH. • We tracked the quantitative changes of each clone among heterogeneity upon passages. • The changes of cytogenetic profile upon passages were similar to cancer stem cell. - Abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during

  13. Cytogenetic heterogeneity and their serial dynamic changes during acquisition of cytogenetic aberrations in cultured mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung-Ah [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Im, Kyong Ok; Park, Si Nae; Kwon, Ji Seok [Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Seon Young [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Oh, Keunhee; Lee, Dong-Sup [Laboratory of Immunology and Cancer Biology, Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul (Korea, Republic of); Transplantation Research Institute, Seoul National University College of Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Min Kyung; Kim, Seong Who [Department of Biochemistry and Molecular Biology, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Jang, Mi; Lee, Gene [Lab of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul (Korea, Republic of); Oh, Yeon-Mok; Lee, Sang Do [Department of Pulmonary and Critical Care Medicine, Asthma Center and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Lee, Dong Soon, E-mail: soonlee@snu.ac.kr [Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2015-07-15

    Highlights: • We evaluated cytogenetic aberrations of MSC during culture using G-banding and FISH. • We tracked the quantitative changes of each clone among heterogeneity upon passages. • The changes of cytogenetic profile upon passages were similar to cancer stem cell. - Abstract: To minimize the risk of tumorigenesis in mesenchymal stem cells (MSCs), G-banding analysis is widely used to detect chromosomal aberrations in MSCs. However, a critical limitation of G-banding is that it only reflects the status of metaphase cells, which can represent as few as 0.01% of tested cells. During routine cytogenetic testing in MSCs, we often detect chromosomal aberrations in minor cell populations. Therefore, we aimed to investigate whether such a minority of cells can expand over time or if they ultimately disappear during MSC passaging. We passaged MSCs serially while monitoring quantitative changes for each aberrant clone among heterogeneous MSCs. To investigate the cytogenetic status of interphase cells, which represent the main population, we also performed interphase FISH analysis, in combination with G-banding and telomere length determination. In human adipose tissue-derived MSCs, 4 types of chromosomal aberrations were found during culturing, and in umbilical cord MSCs, 2 types of chromosomal aberrations were observed. Sequential dynamic changes among heterogeneous aberrant clones during passaging were similar to the dynamic changes observed in cancer stem cells during disease progression. Throughout all passages, the quantitative G-banding results were inconsistent with those of the interphase FISH analysis. Interphase FISH revealed hidden aberrations in stem cell populations with normal karyotypes by G-banding analysis. We found that telomere length gradually decreased during passaging until the point at which cytogenetic aberrations appeared. The present study demonstrates that rare aberrant clones at earlier passages can become predominant clones during

  14. Adult hippocampal neurogenesis poststroke: More new granule cells but aberrant morphology and impaired spatial memory.

    Science.gov (United States)

    Woitke, Florus; Ceanga, Mihai; Rudolph, Max; Niv, Fanny; Witte, Otto W; Redecker, Christoph; Kunze, Albrecht; Keiner, Silke

    2017-01-01

    Stroke significantly stimulates neurogenesis in the adult dentate gyrus, though the functional role of this postlesional response is mostly unclear. Recent findings suggest that newborn neurons generated in the context of stroke may fail to correctly integrate into pre-existing networks. We hypothesized that increased neurogenesis in the dentate gyrus following stroke is associated with aberrant neurogenesis and impairment of hippocampus-dependent memory. To address these questions we used the middle cerebral artery occlusion model (MCAO) in mice. Animals were housed either under standard conditions or with free access to running wheels. Newborn granule cells were labelled with the thymidine analoque EdU and retroviral vectors. To assess memory performance, we employed a modified version of the Morris water maze (MWM) allowing differentiation between hippocampus dependent and independent learning strategies. Newborn neurons were morphologically analyzed using confocal microscopy and Neurolucida system at 7 weeks. We found that neurogenesis was significantly increased following MCAO. Animals with MCAO needed more time to localize the platform and employed less hippocampus-dependent search strategies in MWM versus controls. Confocal studies revealed an aberrant cell morphology with basal dendrites and an ectopic location (e.g. hilus) of new granule cells born in the ischemic brain. Running increased the number of new neurons but also enhanced aberrant neurogenesis. Running, did not improve the general performance in the MWM but slightly promoted the application of precise spatial search strategies. In conclusion, ischemic insults cause hippocampal-dependent memory deficits which are associated with aberrant neurogenesis in the dentate gyrus indicating ischemia-induced maladaptive plasticity in the hippocampus.

  15. Effect of yeast TEL1 gene expression in A-T cells on chromosome aberration induced by radiation

    International Nuclear Information System (INIS)

    Cao Jianping; Zheng Siying; Zhu Wei; Luo Jialin; Zhou Xianfeng; Wang Mingming

    2004-01-01

    Objective: To analyze the effect of yeast TEL1 gene expression in human A-T (ataxia-telangiectasia) cells on chromosome aberration induced by radiation. Methods: Yeast TEL1 gene (TEL1rep), TEL1 fragment (deltaTELrep), pRep5 vector were stably transfected into A-T cells and pRep5 vector was stably transfected into GM639 cells. respectively. The stably transfected A-T and GM639 cells, namely, AT-TEL1, AT-deltaTEL1, AT-rep, GM-rep, were grown selectively in Dulbecco's minimal essential medium (DMEM) containing 100 μg/ml hygromycin, while non-transfected A-T and GM639 cells were grown in DMEM containing 15%220% FBS. 60 Co γ-rays were used to irradiate the above cells at exponential phase. The irradiation dose was 0, 1, 3 Gy, respectively. A hundred metaphases were analyzed for microscopically detectable chromosome type and chromatid type aberrations. Results: The chromosome numbers of all transfected, and non-transfected A-T, GM639 fobroblasts were aneuploid. Both spontaneous and radiation-induced chromosome aberration frequencies of A-T cells were higher than those of GM639 control cells. There is no significant difference in the spontaneous chromosome aberration between TEL1 gene stably transfected A-T cells (AT-TEL1) and non-transfected A-T cells (P>0.05). Chromosome aberration frequencies induced by radiation in AT-TEL1 cells were significantly lower than those of A-T cells (P<0.01). However, chromosome aberration frequencies induced by radiation in AT-deltaTEL1 and AT-rep cells were higher than those of A-T cells. Conclusion: The expression of yeast TEL1 gene in human A-T cells can significantly decrease the chromosome aberration frequencies induced by radiation. (authors)

  16. Anthocyanins influence tannin-cell wall interactions.

    Science.gov (United States)

    Bautista-Ortín, Ana Belén; Martínez-Hernández, Alejandro; Ruiz-García, Yolanda; Gil-Muñoz, Rocío; Gómez-Plaza, Encarna

    2016-09-01

    The rate of tannin extraction was studied in a vinification of red grapes and the results compared with another vinification made with white grapes fermented as for typical red wine, in the presence of skins and seeds. Even though the grapes presented a quite similar skin and seed tannin content, the differences in tannin concentration between both vinifications was very large, despite the fact that the only apparent difference between the phenolic composition of both wines was the anthocyanin content. This suggests that anthocyanins play an important role in tannin extractability, perhaps because they affect the extent of the tannin-cell wall interaction, a factor that largely controls the resulting quantity of tannins in wines. To confirm this observation, the effect of anthocyanins on the tannin extractability from grape seeds and skin and on the interaction between tannins and grape cell walls suspended in model solutions were studied. The results indicated that anthocyanins favored skin and seed tannin extraction and that there is a competition for the adsorption sites between anthocyanins and tannins that increases the tannin content when anthocyanins are present. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Introduction of chromosome aberrations in mammalian cells after heavy ion exposure

    International Nuclear Information System (INIS)

    Ritter, S.; Kraft-Weyrather, W.; Scholz, M.; Kraft, G.

    1991-01-01

    The induction of chromosome aberrations by heavy charged particles was studied in V79 Chinese hamster cells over a wide range of energies (3-100 MeV/u) and LET (20-16000 keV/μm). For comparison, X-ray experiments were performed. Our data indicate quantitative and qualitative differences in the response of cells to particle and x-ray irradiation. For the same level of cell survival the amount of damaged cells which can be observed is smaller in heavy ion (11.4 MeV/u Ar) irradiated samples. The highest yield of damaged cells is found 8 to 12 hours after particle irradiation and 4 hours after x-irradiation. Differences in the amounts of damaged cells are attributed to cell cycle perturbations which interfere with the expression of damage. After heavy ion exposure the amount of cells reaching mitosis (mitotic index) decreases drastically and not all damaged cells reach mitosis with 48 hours after exposure. A portion of cells die in interphase. Cell cycle delays induced by x-ray irradiation are less pronounced and all cells reach the first post-irradiation mitosis within 24 hours after irradiation. Additionally, the damage produced by charged particles seems to be more severe. The disintegration of chromosomes was only observed after high LET radiation; an indication of the high and local energy deposition in the particle track. Only cross sections for the induction of chromosome aberrations in mitotic cells were reported in this paper because of the problems arising from the drastic cell cycle perturbations. In this case, cells were irradiated in mitosis and assayed immediately. (orig.)

  18. Disruption of cell walls for enhanced lipid recovery

    Science.gov (United States)

    Knoshaug, Eric P; Donohoe, Bryon S; Gerken, Henri; Laurens, Lieve; Van Wychen, Stefanie Rose

    2015-03-24

    Presented herein are methods of using cell wall degrading enzymes for recovery of internal lipid bodies from biomass sources such as algae. Also provided are algal cells that express at least one exogenous gene encoding a cell wall degrading enzyme and methods for recovering lipids from the cells.

  19. Spontaneous and induced chromosomal aberrations in bone marrow cells of mice of different strain and age

    Energy Technology Data Exchange (ETDEWEB)

    Lil' p, J.G.; Korogodina, Yu.V. (Akademiya Meditsinskikh Nauk SSSR, Moscow. Inst. Meditsinskoj Genetiki)

    1981-01-01

    The sensitivity of bone marrow cell chromosomes both to an alkylating agent thiophosphamide and ..gamma..-irradiation in 101/H, A/He, CBA, BALB/c and C57BL/6 aging mice has been studied. Changes in the sensitivity of bone marrow cell chromosomes with age are shown to depend both on mutagenic effect type and animal's genotype. The age dependent yield of chromosomal aberrations did not change in mice of all studied strains after ..gamma..-irradiation under conditions of our experiments. After the thiophosphamide effect, an increased sensitivity of bone marrow cell chromosomes was observed in the old 101/H, A/He and CBA mice as compared to the young ones. The level of induced chromosomal aberrations in C57BL/6 mice did not vary with age. Cells exhibiting multiple damages to chromosomes occurred in the bone marrow following the thiophosphamide effect. An increased sensitivity of old animals of certain strains resulted mainly from a sharp numerical growth of such cells. No increase in the number of cells in intact animals of all strains related to age dependent chromosomal structural damages was observed, whereas the accumulation of aneuploid cells probably depended on the genotype.

  20. Radiation-induced chromosome aberrations in bone marrow cells leading to acute myeloid leukemia in mouse

    International Nuclear Information System (INIS)

    Nobuhiko Ban; Tomoko Kusama

    1996-01-01

    It is well known that radiation-induced acute myeloid leukemia (RI-AML) in mice is charaterized by deletion and/or rearrangement of chromosome 2. While chromosome 2 has been suspected to be a target of RI-AML, radiation-sensitive site of the chromosome might be implicated in the leukemogenesis. There were few cytogenetical studies, however, focusing on chromosomal rearrangements shortly after irradiation, and little was known about the frequency and pattern of chromosome 2 aberrations during the early period. In this study, metaphase samples were prepared from whole-body irradiated mice 24 hours after irradiation, most of the cells considered to be in the first mitotic stage. Distribution of chromosomal breakpoints on the metaphase samples were analyzed to study the relationship between chromosome aberrations and RI-AML. (author)

  1. Plant cell wall extensibility: connecting plant cell growth with cell wall structure, mechanics, and the action of wall-modifying enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Cosgrove, Daniel J.

    2015-11-25

    The advent of user-friendly instruments for measuring force/deflection curves of plant surfaces at high spatial resolution has resulted in a recent outpouring of reports of the ‘Young's modulus’ of plant cell walls. The stimulus for these mechanical measurements comes from biomechanical models of morphogenesis of meristems and other tissues, as well as single cells, in which cell wall stress feeds back to regulate microtubule organization, auxin transport, cellulose deposition, and future growth directionality. In this article I review the differences between elastic modulus and wall extensibility in the context of cell growth. Some of the inherent complexities, assumptions, and potential pitfalls in the interpretation of indentation force/deflection curves are discussed. Reported values of elastic moduli from surface indentation measurements appear to be 10- to >1000-fold smaller than realistic tensile elastic moduli in the plane of plant cell walls. Potential reasons for this disparity are discussed, but further work is needed to make sense of the huge range in reported values. The significance of wall stress relaxation for growth is reviewed and connected to recent advances and remaining enigmas in our concepts of how cellulose, hemicellulose, and pectins are assembled to make an extensible cell wall. A comparison of the loosening action of α-expansin and Cel12A endoglucanase is used to illustrate two different ways in which cell walls may be made more extensible and the divergent effects on wall mechanics.

  2. Aberrant allele-specific replication, independent of parental origin, in blood cells of cancer patients

    International Nuclear Information System (INIS)

    Dotan, Zohar A; Dotan, Aviva; Ramon, Jacob; Avivi, Lydia

    2008-01-01

    Allelic counterparts of biallelically expressed genes display an epigenetic symmetry normally manifested by synchronous replication, different from genes subjected to monoallelic expression, which normally are characterized by an asynchronous mode of replication (well exemplified by the SNRPN imprinted locus). Malignancy was documented to be associated with gross modifications in the inherent replication-timing coordination between allelic counterparts of imprinted genes as well as of biallelically expressed loci. The cancer-related allelic replication timing aberrations are non-disease specific and appear in peripheral blood cells of cancer patients, including those with solid tumors. As such they offer potential blood markers for non-invasive cancer test. The present study was aimed to gain some insight into the mechanism leading to the replication timing alterations of genes in blood lymphocytes of cancer patients. Peripheral blood samples derived from patients with prostate cancer were chosen to represent the cancerous status, and samples taken from patients with no cancer but with benign prostate hyperplasia were used to portray the normal status. Fluorescence In Situ Hybridization (FISH) replication assay, applied to phytohemagglutinin (PHA)-stimulated blood lymphocytes, was used to evaluate the temporal order (either synchronous or asynchronous) of genes in the patients' cells. We demonstrated that: (i) the aberrant epigenetic profile, as delineated by the cancer status, is a reversible modification, evidenced by our ability to restore the normal patterns of replication in three unrelated loci (CEN15, SNRPN and RB1) by introducing an archetypical demethylating agent, 5-azacytidine; (ii) following the rehabilitating effect of demethylation, an imprinted gene (SNRPN) retains its original parental imprint; and (iii) the choice of an allele between early or late replication in the aberrant asynchronous replication, delineated by the cancer status, is not

  3. Advanced technologies for plant cell wall evolution and diversity

    DEFF Research Database (Denmark)

    Fangel, Jonatan Ulrik

    Plant cell walls consist of polysaccharides, glycoproteins and phenolic polymers interlinked together in a highly complex network. The detailed analysis of cell walls is challenging because of their inherent complexity and heterogeneity. Also, complex carbohydrates, unlike proteins and nucleotide...... angiosperms. This analysis has enabled cell wall diversity to be placed in a phylogenetic context, and, when integrated with transcriptomic and genomic analysis has contributed to our understanding of important aspects of plant evolution....... produced has provided new insight into cell wall evolution and biosynthesis and has contributed to the commercial development of cell wall materials. A major focus of the work has been the wide scale sampling of cell wall diversity across the plant kingdom, from unicellular algae to highly evolved...

  4. Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR.

    Science.gov (United States)

    Romaniuk, Joseph A H; Cegelski, Lynette

    2015-10-05

    The ability to characterize bacterial cell-wall composition and structure is crucial to understanding the function of the bacterial cell wall, determining drug modes of action and developing new-generation therapeutics. Solid-state NMR has emerged as a powerful tool to quantify chemical composition and to map cell-wall architecture in bacteria and plants, even in the context of unperturbed intact whole cells. In this review, we discuss solid-state NMR approaches to define peptidoglycan composition and to characterize the modes of action of old and new antibiotics, focusing on examples in Staphylococcus aureus. We provide perspectives regarding the selected NMR strategies as we describe the exciting and still-developing cell-wall and whole-cell NMR toolkit. We also discuss specific discoveries regarding the modes of action of vancomycin analogues, including oritavancin, and briefly address the reconsideration of the killing action of β-lactam antibiotics. In such chemical genetics approaches, there is still much to be learned from perturbations enacted by cell-wall assembly inhibitors, and solid-state NMR approaches are poised to address questions of cell-wall composition and assembly in S. aureus and other organisms. © 2015 The Author(s).

  5. Chromosome aberrations and rogue cells in lymphocytes of Chernobyl clean-up workers

    International Nuclear Information System (INIS)

    Lazutka, J.R.

    1996-01-01

    A cytogenetic analysis was performed on peripheral blood lymphocytes from 183 Chernobyl clean-up workers and 27 control individuals. Increased frequencies of chromosome aberrations were associated with exposure to radiation at Chernobyl, alcohol abuse and a history of recent influenza infection. However, only approximately 20% of Chernobyl clean-up workers had an increased frequency of dicentric and ring chromosomes. At the same time, an increased frequency of acentric fragments in lymphocytes of clean-up workers was characteristic. The use of multivitamins as dietary supplement significantly decreased the frequency of chromosome aberrations, especially of chromatid breaks. Rogue cells were found in lymphocytes of 28 clean-up workers and 3 control individuals. The appearance of rogue cells was associated with a recent history of acute respiratory disease (presumably caused by adenoviral infection) and, probably, alcohol abuse. Dicentric chromosomes in rogue cells were distributed according to a negative binomial distribution. Occurrence of rogue cells due to a perturbation of cell cycle control and abnormal apoptosis is suggested

  6. Phenolphthalein induces chromosome aberrations in human and Chinese hamster liver cells (CHEL) cultured in vitro.

    Science.gov (United States)

    Biondi, O; Andreozzi, L; Amoruso, S; Motta, S

    2000-01-01

    Phenolphthalein is a nonprescription laxative agent that has been widely used during this century. Recent studies in animal models have shown that phenolphthalein has carcinogenic activity. In order to assess cytogenetic effects on human cells in vitro, we tested phenolphthalein in a chromosome aberration assay in human embryo cells derived from amniotic fluid. Our results show that phenolphthalein induces a significant increase in the frequency of chromosome aberrations in human cells. The lowest dose level at which the clastogenic effect is evident is 23.2 microg/ml. Similar positive results were obtained in a Chinese hamster liver cell line, which is metabolically competent to activate different classes of promutagens and procarcinogens into biologically active metabolites. Instead, parallel experiments in Chinese hamster ovary cells did not show any clastogenic effect due to phenolphthalein. These latter data suggested that phenolphthalein acts as a promutagen and must be metabolically activated to exert its clastogenic effect. Teratogenesis Carcinog. Mutagen. 20:209-217, 2000. Copyright 2000 Wiley-Liss, Inc.

  7. Transchromosomic cell model of Down syndrome shows aberrant migration, adhesion and proteome response to extracellular matrix

    Directory of Open Access Journals (Sweden)

    Cotter Finbarr E

    2009-08-01

    Full Text Available Abstract Background Down syndrome (DS, caused by trisomy of human chromosome 21 (HSA21, is the most common genetic birth defect. Congenital heart defects (CHD are seen in 40% of DS children, and >50% of all atrioventricular canal defects in infancy are caused by trisomy 21, but the causative genes remain unknown. Results Here we show that aberrant adhesion and proliferation of DS cells can be reproduced using a transchromosomic model of DS (mouse fibroblasts bearing supernumerary HSA21. We also demonstrate a deacrease of cell migration in transchromosomic cells independently of their adhesion properties. We show that cell-autonomous proteome response to the presence of Collagen VI in extracellular matrix is strongly affected by trisomy 21. Conclusion This set of experiments establishes a new model system for genetic dissection of the specific HSA21 gene-overdose contributions to aberrant cell migration, adhesion, proliferation and specific proteome response to collagen VI, cellular phenotypes linked to the pathogenesis of CHD.

  8. Multidimensional Solid-State NMR Spectroscopy of Plant Cell Walls

    OpenAIRE

    Wang, Tuo; Phyo, Pyae; Hong, Mei

    2016-01-01

    Plant biomass has become an important source of bio-renewable energy in modern society. The molecular structure of plant cell walls is difficult to characterize by most atomic-resolution techniques due to the insoluble and disordered nature of the cell wall. Solid-state NMR (SSNMR) spectroscopy is uniquely suited for studying native hydrated plant cell walls at the molecular level with chemical resolution. Significant progress has been made in the last five years to elucidate the molecular st...

  9. Small molecule probes for plant cell wall polysaccharide imaging

    Directory of Open Access Journals (Sweden)

    Ian eWallace

    2012-05-01

    Full Text Available Plant cell walls are composed of interlinked polymer networks consisting of cellulose, hemicelluloses, pectins, proteins, and lignin. The ordered deposition of these components is a dynamic process that critically affects the development and differentiation of plant cells. However, our understanding of cell wall synthesis and remodeling, as well as the diverse cell wall architectures that result from these processes, has been limited by a lack of suitable chemical probes that are compatible with live-cell imaging. In this review, we summarize the currently available molecular toolbox of probes for cell wall polysaccharide imaging in plants, with particular emphasis on recent advances in small molecule-based fluorescent probes. We also discuss the potential for further development of small molecule probes for the analysis of cell wall architecture and dynamics.

  10. Detection of chromosomal aberrations in seminomatous germ cell tumours using comparative genomic hybridization

    DEFF Research Database (Denmark)

    Ottesen, A M; Kirchhoff, M; Rajpert-De Meyts, Ewa

    1997-01-01

    Comparative genomic hybridization (CGH) was used to evaluate tissue specimens from 16 seminomas in order to elucidate the pathogenesis of germ cell tumours in males. A characteristic pattern of losses and gains within the entire genomes was detected in 94% of the seminomas by comparing the ratio...... of 12p and 21q appeared most consistently. Results from CGH analysis displayed no relationship to the clinical stages of the malignancy. Some rare aberrations appeared, however, only in clinical stage II and in tumours showing relapse in the contralateral testis following orchiectomy, although...

  11. Proton and Fe Ion-Induced Early and Late Chromosome Aberrations in Different Cell Types

    Science.gov (United States)

    Wu, Honglu; Lu, Tao; Yeshitla, Samrawit; Zhang, Ye; Kadhim, Munira

    2016-01-01

    An early stage of cancer development is believed to be genomic instability (GI) which accelerates the mutation rate in the descendants of the cells surviving radiation exposure. To investigate GI induced by charged particles, we exposed human lymphocytes, human fibroblast cells, and human mammary epithelial cells to high energy protons and Fe ions. In addition, we also investigated GI in bone marrow cells isolated from CBA/CaH (CBA) and C57BL/6 (C57) mice, by analyzing cell survival and chromosome aberrations in the cells after multiple cell divisions. Results analyzed so far from the experiments indicated different sensitivities to charged particles between CBA/CaH (CBA) and C57BL/6 (C57) mouse strains, suggesting that there are two main types of response to irradiation: 1) responses associated with survival of damaged cells and 2) responses associated with the induction of non-clonal chromosomal instability in the surviving progeny of stem cells. Previously, we reported that the RBE for initial chromosome damages was high in human lymphocytes exposed to Fe ions. Our results with different cell types demonstrated different RBE values between different cell types and between early and late chromosomal damages. This study also attempts to offer an explanation for the varying RBE values for different cancer types.

  12. Micronuclei and chromosome aberrations found in bone marrow cells and lymphocytes form thorotrast patients and atomic bomb survivors

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Kimio; Izumi, Takaki; Ohkita, Takeshi; Kamada, Nanao (Hiroshima Univ. (Japan). Research Inst. for Nuclear Medicine and Biology)

    1984-03-01

    As two cytogenetic parameters of radiation exposure, the frequency of micronucleus in erythroblasts, lymphocytes and red cells (Howell-Jolly body) as well as chromosome aberrations in bone marrow cells and in lymphocytes were studied in 24 thorotrast patients and in 32 atomic bomb (A-bomb) survivors who were exposed within one kilometer from the Hiroshima hypocenter. The incidence of both micronucleus and chromosome aberrations in these two exposed groups were significantly higher than that in non-exposed controls. So that these two parameters are useful guide for evaluating the residual effects of radiation, especially on hematopoietic cells. Because of its simple procedures, micronucleus test is also helpful as screening for prediction of chromosome aberrations. The characteristics of lymphocyte chromosome aberrations differed considerably between thorotrast patients and A-bomb survivors; the incidence of unstable type aberrations and intracellular complexity of chromosome aberrations were much higher in the former group. The incidence of micronucleus in erythroblasts and lymphocytes was also higher in thorotrast patients. Such differences are attributable to the differences in the radiation quality (..cap alpha..-ray or ..gamma..-ray+neutron) and in the mode of exposure (persistent or single) of these two groups.

  13. Chromosome Aberrations in Cells Infected with Bovine Papillomavirus: Comparing Cutaneous Papilloma, Esophagus Papilloma, and Urinary Bladder Lesion Cells

    Science.gov (United States)

    Campos, S. R. C.; Melo, T. C.; Assaf, S.; Araldi, R. P.; Mazzuchelli-de-Souza, J.; Sircili, M. P.; Carvalho, R. F.; Roperto, F.; Beçak, W.; Stocco, R. C.

    2013-01-01

    The majority of malignant cells present genetic instability with chromosome number changes plus segmental defects: these changes involve intact chromosomes and breakage-induced alterations. Some pathways of chromosomal instability have been proposed as random breakage, telomere fusion, and centromere fission. Chromosome alterations in tumor cells have been described in animal models and in vitro experiments. One important question is about possible discrepancies between animal models, in vitro studies, and the real events in cancer cells in vivo. Papillomaviruses are relevant agents in oncogenic processes related to action on host genome. Recently, many reports have discussed the presence of virus DNA in peripheral blood, in humans and in animals infected by papillomaviruses. The meaning of this event is of controversy: possible product of apoptosis occurring in cancer cells, metastasized cancer cells, or active DNA sequences circulating in bloodstream. This study compares chromosome aberrations detected in bovine cells, in peripheral blood cells, and in BPV lesion cells: the literature is poor in this type of study. Comparing chromosome aberrations described in the different cells, a common mechanism in their origin, can be suggested. Furthermore blood cells can be evaluated as an effective way of virus transmission. PMID:24298391

  14. Assembly and enlargement of the primary cell wall in plants

    Science.gov (United States)

    Cosgrove, D. J.

    1997-01-01

    Growing plant cells are shaped by an extensible wall that is a complex amalgam of cellulose microfibrils bonded noncovalently to a matrix of hemicelluloses, pectins, and structural proteins. Cellulose is synthesized by complexes in the plasma membrane and is extruded as a self-assembling microfibril, whereas the matrix polymers are secreted by the Golgi apparatus and become integrated into the wall network by poorly understood mechanisms. The growing wall is under high tensile stress from cell turgor and is able to enlarge by a combination of stress relaxation and polymer creep. A pH-dependent mechanism of wall loosening, known as acid growth, is characteristic of growing walls and is mediated by a group of unusual wall proteins called expansins. Expansins appear to disrupt the noncovalent bonding of matrix hemicelluloses to the microfibril, thereby allowing the wall to yield to the mechanical forces generated by cell turgor. Other wall enzymes, such as (1-->4) beta-glucanases and pectinases, may make the wall more responsive to expansin-mediated wall creep whereas pectin methylesterases and peroxidases may alter the wall so as to make it resistant to expansin-mediated creep.

  15. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Darvill, Alan [Univ. of Georgia, Athens, GA (United States); Hahn, Michael G. [Univ. of Georgia, Athens, GA (United States); O' Neill, Malcolm A. [Univ. of Georgia, Athens, GA (United States); York, William S. [Univ. of Georgia, Athens, GA (United States)

    2015-02-17

    Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell walls and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.

  16. Hemicellulose biosynthesis and degradation in tobacco cell walls

    NARCIS (Netherlands)

    Compier, M.G.M.

    2005-01-01

    Natural fibres have a wide range of technological applications, such as in paper and textile industries. The basic properties and the quality of plant fibres are determined by the composition of the plant cell wall. Characteristic for fibres are thick secondary cell walls, which consist of cellulose

  17. original article the use of morphological and cell wall chemical

    African Journals Online (AJOL)

    boaz

    THE USE OF MORPHOLOGICAL AND CELL WALL CHEMICAL MARKERS IN. THE IDENTIFICATION OF ... aerial hyphae, with or without diffusible pigments on medium surface (7, 14). Cell wall components of Actinomycetes enable rapid qualitative identification of certain .... Alexander von Humboldt Foundation and the.

  18. Characterising the cellulose synthase complexes of cell walls

    NARCIS (Netherlands)

    Mansoori Zangir, N.

    2012-01-01

    One of the characteristics of the plant kingdom is the presence of a structural cell wall. Cellulose is a major component in both the primary and secondary cell walls of plants. In higher plants cellulose is synthesized by so called rosette protein complexes with cellulose synthases (CESAs) as

  19. Characterizing phenolformaldehyde adhesive cure chemistry within the wood cell wall

    Science.gov (United States)

    Daniel J. Yelle; John Ralph

    2016-01-01

    Adhesive bonding of wood using phenol-formaldehyde remains the industrial standard in wood product bond durability. Not only does this adhesive infiltrate the cell wall, it also is believed to form primary bonds with wood cell wall polymers, particularly guaiacyl lignin. However, the mechanism by which phenol-formaldehyde adhesive intergrally interacts and bonds to...

  20. Characterising the cellulose synthase complexes of cell walls

    NARCIS (Netherlands)

    Mansoori Zangir, N.

    2012-01-01

    One of the characteristics of the plant kingdom is the presence of a structural cell wall. Cellulose is a major component in both the primary and secondary cell walls of plants. In higher plants cellulose is synthesized by so called rosette protein complexes with cellulose synthases (CESAs) as the

  1. Magnetic domain wall conduits for single cell applications

    DEFF Research Database (Denmark)

    Donolato, Marco; Torti, A.; Kostesha, Natalie

    2011-01-01

    The ability to trap, manipulate and release single cells on a surface is important both for fundamental studies of cellular processes and for the development of novel lab-on-chip miniaturized tools for biological and medical applications. In this paper we demonstrate how magnetic domain walls...... walls technology in lab-on-chip systems devoted to accurate individual cell trapping and manipulation....

  2. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    Science.gov (United States)

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  3. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  4. The effect of track structure on the induction of chromosomal aberrations in murine cells

    Science.gov (United States)

    Durante, M.; Cella, L.; Furusawa, Y.; George, K.; Gialanella, G.; Grossi, G.; Pugliese, M.; Saito, M.; Yang, T. C.

    1998-01-01

    PURPOSE: To measure chromosome aberrations in C3H 10T1/2 mouse fibroblasts using FISH painting at the first mitosis following exposure to 30 keV/microm hydrogen or neon ions. MATERIALS AND METHODS: Cells in plateau-phase were irradiated with 0.86 MeV protons at the TTT-3 Tandem accelerator in Naples (Italy), or with 400 MeV/n Ne ions at the HIMAC accelerator in Chiba (Japan). Colcemid-blocked cells were harvested at the first mitosis following exposure, and chromosome spreads were hybridized in situ with a fluorescein-labelled composite mouse DNA probe specific for chromosomes 2 and 8. RESULTS: Protons were more efficient than neon ions at the same LET in the induction of chromosome interchanges and breaks. Yields of complex exchanges were similar for both particles at the same dose, but protons produced mostly insertions, while with Ne exposure non-reciprocal exchanges were the most frequent complex-type exchange. CONCLUSIONS: Charged particles with the same LET produce different yields of chromosome aberrations, and some observed differences can be explained based on the available track-structure models.

  5. Brassinosteroid Mediated Cell Wall Remodeling in Grasses under Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Xiaolan Rao

    2017-05-01

    Full Text Available Unlike animals, plants, being sessile, cannot escape from exposure to severe abiotic stresses such as extreme temperature and water deficit. The dynamic structure of plant cell wall enables them to undergo compensatory changes, as well as maintain physical strength, with changing environments. Plant hormones known as brassinosteroids (BRs play a key role in determining cell wall expansion during stress responses. Cell wall deposition differs between grasses (Poaceae and dicots. Grass species include many important food, fiber, and biofuel crops. In this article, we focus on recent advances in BR-regulated cell wall biosynthesis and remodeling in response to stresses, comparing our understanding of the mechanisms in grass species with those in the more studied dicots. A more comprehensive understanding of BR-mediated changes in cell wall integrity in grass species will benefit the development of genetic tools to improve crop productivity, fiber quality and plant biomass recalcitrance.

  6. Transcriptional regulatory network controlling secondary cell wall ...

    African Journals Online (AJOL)

    Secondary wall is an abundant component of plant biomass and has a potential to be a renewable resource of bioenergy and biomaterials. It is important to unravel the molecular mechanism underlying secondary wall formation and how it contributes to plant biomass production. In this review, we summarized the potential ...

  7. Architecture and Biosynthesis of the Saccharomyces cerevisiae Cell Wall

    Science.gov (United States)

    Orlean, Peter

    2012-01-01

    The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of β1,3- and β1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, β1,3- and β1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins. PMID:23135325

  8. Branched pectic galactan in phloem-sieve-element cell walls: implications for cell mechanics

    DEFF Research Database (Denmark)

    Torode, Thomas A.; O'Neill, Rachel E.; Marcus, Susan E.

    2017-01-01

    has previously been identified in garlic bulbs in which the LM26 epitope is widespread throughout most cell walls including those of phloem cells. Garlic bulb cell wall material has been used to confirm the association of the LM26 epitope with cell wall pectic rhamnogalacturonan-I (RG...

  9. Aberration-free FTIR spectroscopic imaging of live cells in microfluidic devices.

    Science.gov (United States)

    Chan, K L Andrew; Kazarian, Sergei G

    2013-07-21

    The label-free, non-destructive chemical analysis offered by FTIR spectroscopic imaging is a very attractive and potentially powerful tool for studies of live biological cells. FTIR imaging of live cells is a challenging task, due to the fact that cells are cultured in an aqueous environment. While the synchrotron facility has proven to be a valuable tool for FTIR microspectroscopic studies of single live cells, we have demonstrated that high quality infrared spectra of single live cells using an ordinary Globar source can also be obtained by adding a pair of lenses to a common transmission liquid cell. The lenses, when placed on the transmission cell window, form pseudo hemispheres which removes the refraction of light and hence improve the imaging and spectral quality of the obtained data. This study demonstrates that infrared spectra of single live cells can be obtained without the focus shifting effect at different wavenumbers, caused by the chromatic aberration. Spectra of the single cells have confirmed that the measured spectral region remains in focus across the whole range, while spectra of the single cells measured without the lenses have shown some erroneous features as a result of the shift of focus. It has also been demonstrated that the addition of lenses can be applied to the imaging of cells in microfabricated devices. We have shown that it was not possible to obtain a focused image of an isolated cell in a droplet of DPBS in oil unless the lenses are applied. The use of the approach described herein allows for well focused images of single cells in DPBS droplets to be obtained.

  10. Functional Analysis of Cellulose and Xyloglucan in the Walls of Stomatal Guard Cells of Arabidopsis1[OPEN

    Science.gov (United States)

    Rui, Yue; Anderson, Charles T.

    2016-01-01

    Stomatal guard cells are pairs of specialized epidermal cells that control water and CO2 exchange between the plant and the environment. To fulfill the functions of stomatal opening and closure that are driven by changes in turgor pressure, guard cell walls must be both strong and flexible, but how the structure and dynamics of guard cell walls enable stomatal function remains poorly understood. To address this question, we applied cell biological and genetic analyses to investigate guard cell walls and their relationship to stomatal function in Arabidopsis (Arabidopsis thaliana). Using live-cell spinning disk confocal microscopy, we measured the motility of cellulose synthase (CESA)-containing complexes labeled by green fluorescent protein (GFP)-CESA3 and observed a reduced proportion of GFP-CESA3 particles colocalizing with microtubules upon stomatal closure. Imaging cellulose organization in guard cells revealed a relatively uniform distribution of cellulose in the open state and a more fibrillar pattern in the closed state, indicating that cellulose microfibrils undergo dynamic reorganization during stomatal movements. In cesa3je5 mutants defective in cellulose synthesis and xxt1 xxt2 mutants lacking the hemicellulose xyloglucan, stomatal apertures, changes in guard cell length, and cellulose reorganization were aberrant during fusicoccin-induced stomatal opening or abscisic acid-induced stomatal closure, indicating that sufficient cellulose and xyloglucan are required for normal guard cell dynamics. Together, these results provide new insights into how guard cell walls allow stomata to function as responsive mediators of gas exchange at the plant surface. PMID:26729799

  11. Proximity effects in chromosome aberration induction: Dependence on radiation quality, cell type and dose.

    Science.gov (United States)

    Tello Cajiao, John James; Carante, Mario Pietro; Bernal Rodriguez, Mario Antonio; Ballarini, Francesca

    2018-04-01

    It is widely accepted that, in chromosome-aberration induction, the (mis-)rejoining probability of two chromosome fragments depends on their initial distance, r. However, several aspects of these "proximity effects" need to be clarified, also considering that they can vary with radiation quality, cell type and dose. A previous work performed by the BIANCA (BIophysical ANalysis of Cell death and chromosome Aberrations) biophysical model has suggested that, in human lymphocytes and fibroblasts exposed to low-LET radiation, an exponential function of the form exp(-r/r 0 ), which is consistent with free-end (confined) diffusion, describes proximity effects better than a Gaussian function. Herein, the investigation was extended to intermediate- and high-LET. Since the r 0 values (0.8 μm for lymphocytes and 0.7 μm for fibroblasts) were taken from the low-LET study, the results were obtained by adjusting only one model parameter, i.e. the yield of "Cluster Lesions" (CLs), where a CL was defined as a critical DNA damage producing two independent chromosome fragments. In lymphocytes, the exponential model allowed reproducing both dose-response curves for different aberrations (dicentrics, centric rings and excess acentrics), and values of F-ratio (dicentrics to centric rings) and G-ratio (interstitial deletions to centric rings). In fibroblasts, a good correspondence was found with the dose-response curves, whereas the G-ratio (and, to a lesser extent, the F-ratio) was underestimated. With increasing LET, F decreased and G increased in both cell types, supporting their role as "fingerprints" of high-LET exposure. A dose-dependence was also found at high LET, where F increased with dose and G decreased, possibly due to inter-track effects. We therefore conclude that, independent of radiation quality, in lymphocytes an exponential function can describe proximity effects at both inter- and intra-chromosomal level; on the contrary, in fibroblasts further studies

  12. Cells bearing chromosome aberrations lacking one telomere are selectively blocked at the G2/M checkpoint

    International Nuclear Information System (INIS)

    Rodriguez, Pilar; Barquinero, Joan Francesc; Duran, Assumpta; Caballin, Maria Rosa; Ribas, Montserrat; Barrios, Leonardo

    2009-01-01

    Cell cycle checkpoints are part of the cellular mechanisms to maintain genomic integrity. After ionizing radiation exposure, the cells can show delay or arrest in their progression through the cell cycle, as well as an activation of the DNA repair machinery in order to reduce the damage. The G2/M checkpoint prevents G2 cells entering mitosis until the DNA damage has been reduced. The present study evaluates which G0 radiation-induced chromosome aberrations are negatively selected in the G2/M checkpoint. For this purpose, peripheral blood samples were irradiated at 1 and 3 Gy of γ-rays, and lymphocytes were cultured for 48 h. Calyculin-A and Colcemid were used to analyze, in the same slide, cells in G2 and M. Chromosome spreads were consecutively analyzed by solid stain, pancentromeric and pantelomeric FISH and mFISH. The results show that the frequency of incomplete chromosome elements, those lacking a telomeric signal at one end, decreases abruptly from G2 to M. This indicates that cells with incomplete chromosome elements can progress from G0 to G2, but at the G2/M checkpoint suffer a strong negative selection.

  13. Cells bearing chromosome aberrations lacking one telomere are selectively blocked at the G2/M checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Pilar [Unitat de Biologia Cel.lular, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Barquinero, Joan Francesc [Unitat d' Antropologia Biologica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Duran, Assumpta [Unitat de Biologia Cel.lular, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Caballin, Maria Rosa [Unitat d' Antropologia Biologica, Departament de Biologia Animal, Biologia Vegetal i Ecologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain); Ribas, Montserrat [Servei de Radiofisica i Radioproteccio de l' Hospital de la Santa Creu i Sant Pau, 08025 Barcelona (Spain); Barrios, Leonardo, E-mail: Lleonard.Barrios@uab.cat [Unitat de Biologia Cel.lular, Departament de Biologia Cel.lular, Fisiologia i Immunologia, Universitat Autonoma de Barcelona, 08193 Bellaterra (Spain)

    2009-11-02

    Cell cycle checkpoints are part of the cellular mechanisms to maintain genomic integrity. After ionizing radiation exposure, the cells can show delay or arrest in their progression through the cell cycle, as well as an activation of the DNA repair machinery in order to reduce the damage. The G2/M checkpoint prevents G2 cells entering mitosis until the DNA damage has been reduced. The present study evaluates which G0 radiation-induced chromosome aberrations are negatively selected in the G2/M checkpoint. For this purpose, peripheral blood samples were irradiated at 1 and 3 Gy of {gamma}-rays, and lymphocytes were cultured for 48 h. Calyculin-A and Colcemid were used to analyze, in the same slide, cells in G2 and M. Chromosome spreads were consecutively analyzed by solid stain, pancentromeric and pantelomeric FISH and mFISH. The results show that the frequency of incomplete chromosome elements, those lacking a telomeric signal at one end, decreases abruptly from G2 to M. This indicates that cells with incomplete chromosome elements can progress from G0 to G2, but at the G2/M checkpoint suffer a strong negative selection.

  14. Cell wall remodeling in mycorrhizal symbiosis: a way towards biotrophism.

    Science.gov (United States)

    Balestrini, Raffaella; Bonfante, Paola

    2014-01-01

    Cell walls are deeply involved in the molecular talk between partners during plant and microbe interactions, and their role in mycorrhizae, i.e., the widespread symbiotic associations established between plant roots and soil fungi, has been investigated extensively. All mycorrhizal interactions achieve full symbiotic functionality through the development of an extensive contact surface between the plant and fungal cells, where signals and nutrients are exchanged. The exchange of molecules between the fungal and the plant cytoplasm takes place both through their plasma membranes and their cell walls; a functional compartment, known as the symbiotic interface, is thus defined. Among all the symbiotic interfaces, the complex intracellular interface of arbuscular mycorrhizal (AM) symbiosis has received a great deal of attention since its first description. Here, in fact, the host plasma membrane invaginates and proliferates around all the developing intracellular fungal structures, and cell wall material is laid down between this membrane and the fungal cell surface. By contrast, in ectomycorrhizae (ECM), where the fungus grows outside and between the root cells, plant and fungal cell walls are always in direct contact and form the interface between the two partners. The organization and composition of cell walls within the interface compartment is a topic that has attracted widespread attention, both in ecto- and endomycorrhizae. The aim of this review is to provide a general overview of the current knowledge on this topic by integrating morphological observations, which have illustrated cell wall features during mycorrhizal interactions, with the current data produced by genomic and transcriptomic approaches.

  15. Phospho-specific flow cytometry identifies aberrant signaling in indolent B-cell lymphoma

    Directory of Open Access Journals (Sweden)

    Blix Egil S

    2012-10-01

    -induced phosphorylation of signaling proteins in distinct cell populations can be used to identify aberrant signaling pathways.

  16. Arabidopsis Regenerating Protoplast: A Powerful Model System for Combining the Proteomics of Cell Wall Proteins and the Visualization of Cell Wall Dynamics

    Directory of Open Access Journals (Sweden)

    Ryusuke Yokoyama

    2016-11-01

    Full Text Available The development of a range of sub-proteomic approaches to the plant cell wall has identified many of the cell wall proteins. However, it remains difficult to elucidate the precise biological role of each protein and the cell wall dynamics driven by their actions. The plant protoplast provides an excellent means not only for characterizing cell wall proteins, but also for visualizing the dynamics of cell wall regeneration, during which cell wall proteins are secreted. It therefore offers a unique opportunity to investigate the de novo construction process of the cell wall. This review deals with sub-proteomic approaches to the plant cell wall through the use of protoplasts, a methodology that will provide the basis for further exploration of cell wall proteins and cell wall dynamics.

  17. Synthesis and Application of Plant Cell Wall Oligogalactans

    DEFF Research Database (Denmark)

    Andersen, Mathias Christian Franch

    The plant cell walls represent almost 50% of the biomass found in plants and are therefore one of the main targets for biotechnological research. Major motivators are their potential as a renewable energy source for transport fuels, as functional foods, and as a source of raw materials to generate...... chemical building blocks for industrial processes. To achieve a sustainable development it is necessary to optimize plant production and utilization. This will require a better understanding of the cell wall structure and function at the molecular level. The cell wall is composed by an intricate network...

  18. 2D-immunoblotting analysis of Sporothrix schenckii cell wall

    Directory of Open Access Journals (Sweden)

    Estela Ruiz-Baca

    2011-03-01

    Full Text Available We utilized two-dimensional gel electrophoresis and immunoblotting (2D-immunoblotting with anti-Sporothrix schenckii antibodies to identify antigenic proteins in cell wall preparations obtained from the mycelial and yeast-like morphologies of the fungus. Results showed that a 70-kDa glycoprotein (Gp70 was the major antigen detected in the cell wall of both morphologies and that a 60-kDa glycoprotein was present only in yeast-like cells. In addition to the Gp70, the wall from filament cells showed four proteins with molecular weights of 48, 55, 66 and 67 kDa, some of which exhibited several isoforms. To our knowledge, this is the first 2D-immunoblotting analysis of the S. schenckii cell wall.

  19. Fracture mechanics of the cell wall of Chara corallina.

    Science.gov (United States)

    Toole, G A; Gunning, P A; Parker, M L; Smith, A C; Waldron, K W

    2001-03-01

    Previous mechanical studies using algae have concentrated on cell extension and growth using creep-type experiments, but there appears to be no published study of their failure properties. The mechanical strength of single large internode cell walls (up to 2 mm diameter and 100 mm in length) of the charophyte (giant alga) Chara corallina was determined by dissecting cells to give sheets of cell wall, which were then notched and fractured under tension. Tensile tests, using a range of notch sizes, were conducted on cell walls of varying age and maturity to establish their notch sensitivity and to investigate the propagation of cracks in plant cell walls. The thickness and stiffness of the walls increased with age whereas their strength was little affected. The strength of unnotched walls was estimated as 47+/-13 MPa, comparable to that of some grasses but an order of magnitude higher than that published for model bacterial cellulose composite walls. The strength was notch-sensitive and the critical stress intensity factor K1c was estimated to be 0.63+/-0.19 MNm(-3/2), comparable to published values for grasses.

  20. Cell Wall Metabolism in Response to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Hyacinthe Le Gall

    2015-02-01

    Full Text Available This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic, transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i an increased level in xyloglucan endotransglucosylase/hydrolase (XTH and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

  1. Investigation of Plant Cell Wall Properties: A Study of Contributions from the Nanoscale to the Macroscale Impacting Cell Wall Recalcitrance

    Science.gov (United States)

    Crowe, Jacob Dillon

    Biochemical conversion of lignocellulosic biomass to fuel ethanol is one of a few challenging, yet opportune technologies that can reduce the consumption of petroleum-derived transportation fuels, while providing parallel reductions in greenhouse gas emissions. Biomass recalcitrance, or resistance to deconstruction, is a major technical challenge that limits effective conversion of biomass to fermentable sugars, often requiring a costly thermochemical pretreatment step to improve biomass deconstruction. Biomass recalcitrance is imparted largely by the secondary cell wall, a complex polymeric matrix of cell wall polysaccharides and aromatic heteropolymers, that provides structural stability to cells and enables plant upright growth. Polymers within the cell wall can vary both compositionally and structurally depending upon plant species and anatomical fraction, and have varied responses to thermochemical pretreatments. Cell wall properties impacting recalcitrance are still not well understood, and as a result, the goal of this dissertation is to investigate structural features of the cell wall contributing to recalcitrance (1) in diverse anatomical fractions of a single species, (2) in response to diverse pretreatments, and (3) resulting from genetic modification. In the first study, feedstock cell wall heterogeneity was investigated in anatomical (stem, leaf sheaths, and leaf blades) and internode fractions of switchgrass at varying tissue maturities. Lignin content was observed as the key contributor to recalcitrance in maturing stem tissues only, with non-cellulosic substituted glucuronoarabinoxylans and pectic polysaccharides contributing to cell wall recalcitrance in leaf sheath and leaf blades. Hydroxycinnamate (i.e., saponifiable p-coumarate and ferulate) content along with xylan and pectin extractability decreased with tissue maturity, suggesting lignification is only one component imparting maturity specific cell wall recalcitrance. In the second study

  2. Structural analysis of cell wall polysaccharides using PACE

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, Jennifer C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Institute

    2017-01-01

    The plant cell wall is composed of many complex polysaccharides. The composition and structure of the polysaccharides affect various cell properties including cell shape, cell function and cell adhesion. Many techniques to characterize polysaccharide structure are complicated, requiring expensive equipment and specialized operators e.g. NMR, MALDI-MS. PACE (Polysaccharide Analysis using Carbohydrate gel Electrophoresis) uses a simple, rapid technique to analyze polysaccharide quantity and structure (Goubet et al. 2002). Whilst the method here describes xylan analysis, it can be applied (by use of the appropriate glycosyl hydrolase) to any cell wall polysaccharide.

  3. Growth of Walled Cells: From Shells to Vesicles

    Science.gov (United States)

    Boudaoud, Arezki

    2003-07-01

    The growth of isolated walled cells is investigated. Examples of such cells range from bacteria to giant algae, and include cochlear hair, plant root hair, fungi, and yeast cells. They are modeled as elastic shells containing a liquid. Cell growth is driven by fluid pressure and is is similar to a plastic deformation of the wall. The requirement of mechanical equilibrium leads to two new scaling laws for cell size that are in quantitative agreement with the compiled biological data. Given these results, possible shapes for growing cells are computed by analogy with those of vesicle membranes.

  4. On the growth of walled cells: From shells to vesicles.

    Science.gov (United States)

    Boudaoud, Arezki

    2003-03-01

    The growth of isolated walled cells is investigated. Examples of such cells range from bacteria to giant algae, and include cochlear hair, plant root hair, fungi and yeast cells. They are modeled as elastic shells inflated by a liquid. Cell growth is driven by fluid pressure and is similar to a plastic deformation of the wall. The requirement of mechanical equilibrium leads to two new scaling laws for cell size that are in quantitative agreement with the compiled biological data. Given these results, possible shapes for growing cells are computed by analogy with those of vesicle membranes.

  5. Plant Physiology: FERONIA Defends the Cell Walls against Corrosion.

    Science.gov (United States)

    Verger, Stéphane; Hamant, Olivier

    2018-03-05

    A new study uncovers the role of wall sensing and remodeling in the plant response to salt stress, identifying the FERONIA receptor kinase as a key player in that process, likely through direct sensing of cell wall pectins. Copyright © 2018 Elsevier Ltd. All rights reserved.

  6. Induction of chromosomal aberrations in human primary fibroblasts and immortalized cancer cells exposed to extremely-low-frequency electromagnetic fields

    International Nuclear Information System (INIS)

    Seyyedi, S. S.; Mozdarani, H.; Rezaei Tavirani, M.; Heydari, S.

    2010-01-01

    Rapidly increasing possibilities of exposure to environmental extremely low-frequency electromagnetic fields have become a topic of worldwide investigation. Epidemiological and laboratory studies suggest that exposure to extremely low-frequency electromagnetic fields may increase cancer risk therefore assessment of chromosomal damage in various cell lines might be of predictive value for future risk estimation. Materials and Methods: Primary cultures of fibroblasts from human skin biopsy were exposed to continuous extremely low-frequency electromagnetic fields (3, 50 and 60 Hz, sinusoidal, 3h, and 4 m T). Also immortalized cell lines, SW480, MCF-7 and 1321N1 were exposed to continuous extremely low-frequency electromagnetic fields (50 Hz, sinusoidal, 3 h, 4 m T). Metaphase plates Were prepared according to standard methods and stained in 5% Giemsa solution. Chromosomal aberrations of both chromosome and chromatid types were scored to evaluate the effects of extremely low-frequency electromagnetic fields on primary or established cell lines. Results: Results indicate that by increasing the frequency of extremely low-frequency electromagnetic fields, chromosomal aberrations were increased up to 7-fold above background levels in primary human fibroblast cells. In addition, continuous exposure to a 50 Hz electromagnetic field led to a significant increase in chromosomal aberrations in SW480, MCF-7 and 1321N1 cell lines compared to sham control. Conclusion: Results obtained indicate that extremely low-frequency electromagnetic fields has the potential for induction of chromosomal aberrations in all cell types.

  7. The essential YycFG two-component system controls cell wall metabolism in Bacillus subtilis

    DEFF Research Database (Denmark)

    Bisicchia, Paola; Noone, David; Lioliou, Efthimia

    2007-01-01

    Adaptation of bacteria to the prevailing environmental and nutritional conditions is often mediated by two-component signal transduction systems (TCS). The Bacillus subtilis YycFG TCS has attracted special attention as it is essential for viability and its regulon is poorly defined. Here we show...... that YycFG is a regulator of cell wall metabolism. We have identified five new members of the YycFG regulon: YycF activates expression of yvcE, lytE and ydjM and represses expression of yoeB and yjeA. YvcE(CwlO) and LytE encode endopeptidase-type autolysins that participate in peptidoglycan synthesis...... to lysozyme digestion and YdjM is also predicted to have a role in cell wall metabolism. A genetic analysis shows that YycFG essentiality is polygenic in nature, being a manifestation of disrupted cell wall metabolism caused by aberrant expression of a number of YycFG regulon genes....

  8. Aberrantly Expressed Long Non-Coding RNAs In CD8+T Cells Response to Active Tuberculosis.

    Science.gov (United States)

    Fu, Yurong; Gao, Kunshan; Tao, Enxue; Li, Ruifang; Yi, Zhengjun

    2017-12-01

    Dysregulated expression of long noncoding RNAs (lncRNAs) has been demonstrated as being implicated in a variety of human diseases. In the study we aimed to determine lncRNA profile in CD8 + T cells response to active tuberculosis (TB). We examined the lncRNA expression by microarray in circulating CD8 + T cells isolated from patients with active TB and healthy controls. Change predictions to analysis was used to address functional roles of the deregulated mRNAs. Real-time quantitative PCR (RT-qPCR) was used to validate the microarray result. In total, 328 lncRNAs and 356 mRNAs were differentially expressed in TB CD8 + T cells. Upregulated mRNAs were mainly enriched in cAMP signaling pathway, calcium signaling pathway, and TGF-beta signaling pathway, while downregulated mRNAs were enriched in antigen processing and presentation and natural killer cell mediated cytotoxicity in TB CD8 + T cells. Interestingly, we found that heme oxygenase 1 (HMOX1) was decreased in active TB CD8 + T cells, while its nearby lincRNA XLOC_014219 was upregulated. Subsequent RT-qPCR results confirmed the changes. This is the first research addressing lncRNA expression profiles in active TB CD8 + T cells. The aberrantly expressed lncRNAs observed in the study may provide clues to the dysfunction of CD8 + T cells and so to the pathophysiological properties of active TB. Further studies should focus on the function of lncRNAs involved in active TB. J. Cell. Biochem. 118: 4275-4284, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  9. The aberrant asynchronous replication — characterizing lymphocytes of cancer patients — is erased following stem cell transplantation

    International Nuclear Information System (INIS)

    Nagler, Arnon; Cytron, Samuel; Mashevich, Maya; Korenstein-Ilan, Avital; Avivi, Lydia

    2010-01-01

    Aberrations of allelic replication timing are epigenetic markers observed in peripheral blood cells of cancer patients. The aberrant markers are non-cancer-type-specific and are accompanied by increased levels of sporadic aneuploidy. The study aimed at following the epigenetic markers and aneuploidy levels in cells of patients with haematological malignancies from diagnosis to full remission, as achieved by allogeneic stem cell transplantation (alloSCT). TP53 (a tumor suppressor gene assigned to chromosome 17), AML1 (a gene assigned to chromosome 21 and involved in the leukaemia-abundant 8;21 translocation) and the pericentomeric satellite sequence of chromosome 17 (CEN17) were used for replication timing assessments. Aneuploidy was monitored by enumerating the copy numbers of chromosomes 17 and 21. Replication timing and aneuploidy were detected cytogenetically using fluorescence in situ hybridization (FISH) technology applied to phytohemagglutinin (PHA)-stimulated lymphocytes. We show that aberrant epigenetic markers are detected in patients with hematological malignancies from the time of diagnosis through to when they are scheduled to undergo alloSCT. These aberrations are unaffected by the clinical status of the disease and are displayed both during accelerated stages as well as in remission. Yet, these markers are eradicated completely following stem cell transplantation. In contrast, the increased levels of aneuploidy (irreversible genetic alterations) displayed in blood lymphocytes at various stages of disease are not eliminated following transplantation. However, they do not elevate and remain unchanged (stable state). A demethylating anti-cancer drug, 5-azacytidine, applied in vitro to lymphocytes of patients prior to transplantation mimics the effect of transplantation: the epigenetic aberrations disappear while aneuploidy stays unchanged. The reversible nature of the replication aberrations may serve as potential epigenetic blood markers for evaluating

  10. Analysis of structural and numerical chromosomal aberrations at the first and second mitosis after X irradiation of two-cell mouse embryos

    International Nuclear Information System (INIS)

    Weissenborn, U.; Streffer, C.

    1989-01-01

    Two-cell mouse embryos were X-irradiated in the late G2 phase in vivo. The first and second postradiation mitoses were analyzed for chromosomal anomalies. The majority of structural aberrations visible at the first mitosis after irradiation were chromatid breaks and chromatid gaps; only a few interchanges and dicentrics were observed. The aberration frequency resulted in a dose-effect relationship which was well described by a linear model. At the second mitosis 29% of the structural aberrations of the first mitosis were counted; the aberration quality changed only slightly. It is discussed whether these aberrations are to be considered new, derived, or unchanged transmitted aberrations. Contrary to the results obtained after irradiation of one-cell embryos, little chromosome loss was induced by radiation in two-cell embryos

  11. Apoptosis-Like Cell Death Induction and Aberrant Fibroblast Properties in Human Incisional Hernia Fascia

    Science.gov (United States)

    Diaz, Ramon; Quiles, Maria T.; Guillem-Marti, Jordi; Lopez-Cano, Manuel; Huguet, Pere; Ramon-y-Cajal, Santiago; Reventos, Jaume; Armengol, Manel; Arbos, Maria A.

    2011-01-01

    Incisional hernia often occurs following laparotomy and can be a source of serious problems. Although there is evidence that a biological cause may underlie its development, the mechanistic link between the local tissue microenvironment and tissue rupture is lacking. In this study, we used matched tissue-based and in vitro primary cell culture systems to examine the possible involvement of fascia fibroblasts in incisional hernia pathogenesis. Fascia biopsies were collected at surgery from incisional hernia patients and non-incisional hernia controls. Tissue samples were analyzed by histology and immunoblotting methods. Fascia primary fibroblast cultures were assessed at morphological, ultrastructural, and functional levels. We document tissue and fibroblast loss coupled to caspase-3 activation and induction of apoptosis-like cell-death mechanisms in incisional hernia fascia. Alterations in cytoskeleton organization and solubility were also observed. Incisional hernia fibroblasts showed a consistent phenotype throughout early passages in vitro, which was characterized by significantly enhanced cell proliferation and migration, reduced adhesion, and altered cytoskeleton properties, as compared to non-incisional hernia fibroblasts. Moreover, incisional hernia fibroblasts displayed morphological and ultrastructural alterations compatible with autophagic processes or lysosomal dysfunction, together with enhanced sensitivity to proapoptotic challenges. Overall, these data suggest an ongoing complex interplay of cell death induction, aberrant fibroblast function, and tissue loss in incisional hernia fascia, which may significantly contribute to altered matrix maintenance and tissue rupture in vivo. PMID:21641387

  12. Evolution of the cell wall components during terrestrialization

    OpenAIRE

    Alicja Banasiak

    2014-01-01

    Colonization of terrestrial ecosystems by the first land plants, and their subsequent expansion and diversification, were crucial for the life on the Earth. However, our understanding of these processes is still relatively poor. Recent intensification of studies on various plant organisms have identified the plant cell walls are those structures, which played a key role in adaptive processes during the evolution of land plants. Cell wall as a structure protecting protoplasts and showing a hig...

  13. Patterns of expression of cell wall related genes in sugarcane

    Directory of Open Access Journals (Sweden)

    Lima D.U.

    2001-01-01

    Full Text Available Our search for genes related to cell wall metabolism in the sugarcane expressed sequence tag (SUCEST database (http://sucest.lbi.dcc.unicamp.br resulted in 3,283 reads (1% of the total reads which were grouped into 459 clusters (potential genes with an average of 7.1 reads per cluster. To more clearly display our correlation coefficients, we constructed surface maps which we used to investigate the relationship between cell wall genes and the sugarcane tissues libraries from which they came. The only significant correlations that we found between cell wall genes and/or their expression within particular libraries were neutral or synergetic. Genes related to cellulose biosynthesis were from the CesA family, and were found to be the most abundant cell wall related genes in the SUCEST database. We found that the highest number of CesA reads came from the root and stem libraries. The genes with the greatest number of reads were those involved in cell wall hydrolases (e.g. beta-1,3-glucanases, xyloglucan endo-beta-transglycosylase, beta-glucosidase and endo-beta-mannanase. Correlation analyses by surface mapping revealed that the expression of genes related to biosynthesis seems to be associated with the hydrolysis of hemicelluloses, pectin hydrolases being mainly associated with xyloglucan hydrolases. The patterns of cell wall related gene expression in sugarcane based on the number of reads per cluster reflected quite well the expected physiological characteristics of the tissues. This is the first work to provide a general view on plant cell wall metabolism through the expression of related genes in almost all the tissues of a plant at the same time. For example, developing flowers behaved similarly to both meristematic tissues and leaf-root transition zone tissues. Besides providing a basis for future research on the mechanisms of plant development which involve the cell wall, our findings will provide valuable tools for plant engineering in the

  14. Flavonoid insertion into cell walls improves wood properties.

    Science.gov (United States)

    Ermeydan, Mahmut A; Cabane, Etienne; Masic, Admir; Koetz, Joachim; Burgert, Ingo

    2012-11-01

    Wood has an excellent mechanical performance, but wider utilization of this renewable resource as an engineering material is limited by unfavorable properties such as low dimensional stability upon moisture changes and a low durability. However, some wood species are known to produce a wood of higher quality by inserting mainly phenolic substances in the already formed cell walls--a process so-called heartwood formation. In the present study, we used the heartwood formation in black locust (Robinia pseudoacacia) as a source of bioinspiration and transferred principles of the modification in order to improve spruce wood properties (Picea abies) by a chemical treatment with commercially available flavonoids. We were able to effectively insert hydrophobic flavonoids in the cell wall after a tosylation treatment for activation. The chemical treatment reduced the water uptake of the wood cell walls and increased the dimensional stability of the bulk spruce wood. Further analysis of the chemical interaction of the flavonoid with the structural cell wall components revealed the basic principle of this bioinspired modification. Contrary to established modification treatments, which mainly address the hydroxyl groups of the carbohydrates with hydrophilic substances, the hydrophobic flavonoids are effective by a physical bulking in the cell wall most probably stabilized by π-π interactions. A biomimetic transfer of the underlying principle may lead to alternative cell wall modification procedures and improve the performance of wood as an engineering material.

  15. Multi-gene fluorescence in situ hybridization to detect cell cycle gene copy number aberrations in young breast cancer patients.

    Science.gov (United States)

    Li, Chunyan; Bai, Jingchao; Hao, Xiaomeng; Zhang, Sheng; Hu, Yunhui; Zhang, Xiaobei; Yuan, Weiping; Hu, Linping; Cheng, Tao; Zetterberg, Anders; Lee, Mong-Hong; Zhang, J

    2014-01-01

    Breast cancer is a disease of cell cycle, and the dysfunction of cell cycle checkpoints plays a vital role in the occurrence and development of breast cancer. We employed multi-gene fluorescence in situ hybridization (M-FISH) to investigate gene copy number aberrations (CNAs) of 4 genes (Rb1, CHEK2, c-Myc, CCND1) that are involved in the regulation of cell cycle, in order to analyze the impact of gene aberrations on prognosis in the young breast cancer patients. Gene copy number aberrations of these 4 genes were more frequently observed in young breast cancer patients when compared with the older group. Further, these CNAs were more frequently seen in Luminal B type, Her2 overexpression, and tiple-negative breast cancer (TNBC) type in young breast cancer patients. The variations of CCND1, Rb1, and CHEK2 were significantly correlated with poor survival in the young breast cancer patient group, while the amplification of c-Myc was not obviously correlated with poor survival in young breast cancer patients. Thus, gene copy number aberrations (CNAs) of cell cycle-regulated genes can serve as an important tool for prognosis in young breast cancer patients.

  16. How the deposition of cellulose microfibrils builds cell wall architecture

    NARCIS (Netherlands)

    Emons, A.M.C.; Mulder, B.M.

    2000-01-01

    Cell walls, the extracytoplasmic matrices of plant cells, consist of an ordered array of cellulose microfibrils embedded in a matrix of polysaccharides and glycoproteins. This construction is reminiscent of steel rods in reinforced concrete. How a cell organizes these ordered textures around itself,

  17. Saccharomyces cerevisiae cell wall products: The effects on gut ...

    African Journals Online (AJOL)

    ... no differences between treatments. From the results of this study it appears as if yeast cell wall preparations can contribute to the gastrointestinal health and performance of broiler chickens by affecting mucus secreting goblet cells in a favourable manner. Keywords: Yeast, villi width and height, growth rate, goblet cells ...

  18. Pathway aberrations of murine melanoma cells observed in Paired-End diTag transcriptomes

    Directory of Open Access Journals (Sweden)

    Liu Edison

    2007-06-01

    Full Text Available Abstract Background Melanoma is the major cause of skin cancer deaths and melanoma incidence doubles every 10 to 20 years. However, little is known about melanoma pathway aberrations. Here we applied the robust Gene Identification Signature Paired End diTag (GIS-PET approach to investigate the melanoma transcriptome and characterize the global pathway aberrations. Methods GIS-PET technology directly links 5' mRNA signatures with their corresponding 3' signatures to generate, and then concatenate, PETs for efficient sequencing. We annotated PETs to pathways of KEGG database and compared the murine B16F1 melanoma transcriptome with three non-melanoma murine transcriptomes (Melan-a2 melanocytes, E14 embryonic stem cells, and E17.5 embryo. Gene expression levels as represented by PET counts were compared across melanoma and melanocyte libraries to identify the most significantly altered pathways and investigate the expression levels of crucial cancer genes. Results Melanin biosynthesis genes were solely expressed in the cells of melanocytic origin, indicating the feasibility of using the PET approach for transcriptome comparison. The most significantly altered pathways were metabolic pathways, including upregulated pathways: purine metabolism, aminophosphonate metabolism, tyrosine metabolism, selenoamino acid metabolism, galactose utilization, nitrobenzene degradation, and bisphenol A degradation; and downregulated pathways: oxidative phosphorylation, ATPase synthesis, TCA cycle, pyruvate metabolism, and glutathione metabolism. The downregulated pathways concurrently indicated a slowdown of mitochondrial activities. Mitochondrial permeability was also significantly altered, as indicated by transcriptional activation of ATP/ADP, citrate/malate, Mg++, fatty acid and amino acid transporters, and transcriptional repression of zinc and metal ion transporters. Upregulation of cell cycle progression, MAPK, and PI3K/Akt pathways were more limited to certain

  19. Disruption of microtubule network rescues aberrant actin comets in dynamin2-depleted cells.

    Directory of Open Access Journals (Sweden)

    Yuji Henmi

    Full Text Available A large GTPase dynamin, which is required for endocytic vesicle formation, regulates the actin cytoskeleton through its interaction with cortactin. Dynamin2 mutants impair the formation of actin comets, which are induced by Listeria monocytogenes or phosphatidylinositol-4-phosphate 5-kinase. However, the role of dynamin2 in the regulation of the actin comet is still unclear. Here we show that aberrant actin comets in dynamin2-depleted cells were rescued by disrupting of microtubule networks. Depletion of dynamin2, but not cortactin, significantly reduced the length and the speed of actin comets induced by Listeria. This implies that dynamin2 may regulate the actin comet in a cortactin-independent manner. As dynamin regulates microtubules, we investigated whether perturbation of microtubules would rescue actin comet formation in dynamin2-depleted cells. Treatment with taxol or colchicine created a microtubule-free space in the cytoplasm, and made no difference between control and dynamin2 siRNA cells. This suggests that the alteration of microtubules by dynamin2 depletion reduced the length and the speed of the actin comet.

  20. Disruption of microtubule network rescues aberrant actin comets in dynamin2-depleted cells.

    Science.gov (United States)

    Henmi, Yuji; Tanabe, Kenji; Takei, Kohji

    2011-01-01

    A large GTPase dynamin, which is required for endocytic vesicle formation, regulates the actin cytoskeleton through its interaction with cortactin. Dynamin2 mutants impair the formation of actin comets, which are induced by Listeria monocytogenes or phosphatidylinositol-4-phosphate 5-kinase. However, the role of dynamin2 in the regulation of the actin comet is still unclear. Here we show that aberrant actin comets in dynamin2-depleted cells were rescued by disrupting of microtubule networks. Depletion of dynamin2, but not cortactin, significantly reduced the length and the speed of actin comets induced by Listeria. This implies that dynamin2 may regulate the actin comet in a cortactin-independent manner. As dynamin regulates microtubules, we investigated whether perturbation of microtubules would rescue actin comet formation in dynamin2-depleted cells. Treatment with taxol or colchicine created a microtubule-free space in the cytoplasm, and made no difference between control and dynamin2 siRNA cells. This suggests that the alteration of microtubules by dynamin2 depletion reduced the length and the speed of the actin comet.

  1. Aberrant Promoter Hypermethylation of RASSF Family Members in Merkel Cell Carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Richter, Antje M.; Haag, Tanja; Walesch, Sara [Institute for Genetics, University of Giessen, Giessen D-35392 (Germany); Herrmann-Trost, Peter [Institute of Pathology, Halle D-06097 (Germany); Marsch, Wolfgang C. [Department of Dermatology, University of Halle, Halle D-06120 (Germany); Kutzner, Heinz [DermPath, Friedrichshafen D-88048 (Germany); Helmbold, Peter [Department of Dermatology, University of Heidelberg, Heidelberg D-69120 (Germany); Dammann, Reinhard H., E-mail: Reinhard.Dammann@gen.bio.uni-giessen.de [Institute for Genetics, University of Giessen, Giessen D-35392 (Germany)

    2013-11-18

    Merkel cell carcinoma (MCC) is one of the most aggressive cancers of the skin. RASSFs are a family of tumor suppressors that are frequently inactivated by promoter hypermethylation in various cancers. We studied CpG island promoter hypermethylation in MCC of RASSF2, RASSF5A, RASSF5C and RASSF10 by combined bisulfite restriction analysis (COBRA) in MCC samples and control tissue. We found RASSF2 to be methylated in three out of 43 (7%), RASSF5A in 17 out of 39 (44%, but also 43% in normal tissue), RASSF5C in two out of 26 (8%) and RASSF10 in 19 out of 84 (23%) of the cancer samples. No correlation between the methylation status of the analyzed RASSFs or between RASSF methylation and MCC characteristics (primary versus metastatic, Merkel cell polyoma virus infection, age, sex) was found. Our results show that RASSF2, RASSF5C and RASSF10 are aberrantly hypermethylated in MCC to a varying degree and this might contribute to Merkel cell carcinogenesis.

  2. Characterizing visible and invisible cell wall mutant phenotypes

    Energy Technology Data Exchange (ETDEWEB)

    Carpita, Nicholas C.; McCann, Maureen C.

    2015-04-06

    About 10% of a plant's genome is devoted to generating the protein machinery to synthesize, remodel, and deconstruct the cell wall. High-throughput genome sequencing technologies have enabled a reasonably complete inventory of wall-related genes that can be assembled into families of common evolutionary origin. Assigning function to each gene family member has been aided immensely by identification of mutants with visible phenotypes or by chemical and spectroscopic analysis of mutants with ‘invisible’ phenotypes of modified cell wall composition and architecture that do not otherwise affect plant growth or development. This review connects the inference of gene function on the basis of deviation from the wild type in genetic functional analyses to insights provided by modern analytical techniques that have brought us ever closer to elucidating the sequence structures of the major polysaccharide components of the plant cell wall.

  3. Role of the plant cell wall in gravity resistance.

    Science.gov (United States)

    Hoson, Takayuki; Wakabayashi, Kazuyuki

    2015-04-01

    Gravity resistance, mechanical resistance to the gravitational force, is a principal graviresponse in plants, comparable to gravitropism. The cell wall is responsible for the final step of gravity resistance. The gravity signal increases the rigidity of the cell wall via the accumulation of its constituents, polymerization of certain matrix polysaccharides due to the suppression of breakdown, stimulation of cross-link formation, and modifications to the wall environment, in a wide range of situations from microgravity in space to hypergravity. Plants thus develop a tough body to resist the gravitational force via an increase in cell wall rigidity and the modification of growth anisotropy. The development of gravity resistance mechanisms has played an important role in the acquisition of responses to various mechanical stresses and the evolution of land plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Proteomic analysis of cell walls of two developmental stages of alfalfa stems

    OpenAIRE

    Julian C Verdonk; Ronald D Hatfield; Michael L Sullivan

    2012-01-01

    Cell walls are important for the growth and development of all plants. They are also valuable resources for feed and fiber, and more recently as a potential feedstock for bioenergy production. Cell wall proteins comprise only a fraction of the cell wall, but play important roles in establishing the walls and in the chemical interactions (e.g. crosslinking) of cell wall components. This crosslinking provides structure, but restricts digestibility of cell wall complex carbohydrates, limiting av...

  5. Evaluation of cell wall preparations for proteomics: a new procedure for purifying cell walls from Arabidopsis hypocotyls

    Directory of Open Access Journals (Sweden)

    Canut Hervé

    2006-05-01

    Full Text Available Abstract Background The ultimate goal of proteomic analysis of a cell compartment should be the exhaustive identification of resident proteins; excluding proteins from other cell compartments. Reaching such a goal closely depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific difficulties: (i the lack of a surrounding membrane may result in the loss of cell wall proteins (CWP during the isolation procedure, (ii polysaccharide networks of cellulose, hemicelluloses and pectins form potential traps for contaminants such as intracellular proteins. Several reported procedures to isolate cell walls for proteomic analyses led to the isolation of a high proportion (more than 50% of predicted intracellular proteins. Since isolated cell walls should hold secreted proteins, one can imagine alternative procedures to prepare cell walls containing a lower proportion of contaminant proteins. Results The rationales of several published procedures to isolate cell walls for proteomics were analyzed, with regard to the bioinformatic-predicted subcellular localization of the identified proteins. Critical steps were revealed: (i homogenization in low ionic strength acid buffer to retain CWP, (ii purification through increasing density cushions, (iii extensive washes with a low ionic strength acid buffer to retain CWP while removing as many cytosolic proteins as possible, and (iv absence of detergents. A new procedure was developed to prepare cell walls from etiolated hypocotyls of Arabidopsis thaliana. After salt extraction, a high proportion of proteins predicted to be secreted was released (73%, belonging to the same functional classes as proteins identified using previously described protocols. Finally, removal of intracellular proteins was obtained using detergents, but their amount represented less than 3% in mass of the total protein extract, based on protein quantification. Conclusion The

  6. Sorption of volatile phenols by yeast cell walls

    Directory of Open Access Journals (Sweden)

    Nerea Jiménez-Moreno

    2009-01-01

    Full Text Available Nerea Jiménez-Moreno, Carmen Ancín-AzpilicuetaDepartment of Applied Chemistry, Universidad Pública de Navarra, Pamplona, SpainAbstract: Yeast walls can retain different wine compounds and so its use is interesting in order to eliminate harmful substances from the must which affect alcoholic fermentation (medium chain fatty acids or which affect wine quality in a negative way (ethyl phenols, ochratoxin A. The aim of this study was to examine the capacity of commercial yeast cell walls in eliminating volatile phenols (4-ethylphenol and 4-ethylguaiacol from a synthetic wine that contained 1 mg/L of each one of these compounds. The binding of these compounds to the wall was quite fast which would seem to indicate that the yeast wall-volatile compound union is produced in the outer surface layers of this enological additive. The cell walls used reduced the concentration of 4-ethylphenol and 4-ethylguaiacol, although it would seem that on modifying the matrix of the wine the number of free binding sites on the walls is also modified.Keywords: volatile phenols, yeast cell walls, wine, sorption

  7. Analysis of Chromosomal Aberrations after Low and High Dose Rate Gamma Irradiation in ATM or NBS Suppressed Human Fibroblast Cells

    Science.gov (United States)

    Hada, M.; Huff, J. L.; Patel, Z.; Pluth, J. M.; George, K. A.; Cucinotta, F. A.

    2009-01-01

    A detailed understanding of the biological effects of heavy nuclei is needed for space radiation protection and for cancer therapy. High-LET radiation produces more complex DNA lesions that may be non-repairable or that may require additional processing steps compared to endogenous DSBs, increasing the possibility of misrepair. Interplay between radiation sensitivity, dose, and radiation quality has not been studied extensively. Previously we studied chromosome aberrations induced by low- and high- LET radiation in several cell lines deficient in ATM (ataxia telangactasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. We found that the yields of both simple and complex chromosomal aberrations were significantly increased in the DSB repair defective cells compared to normal cells. The increased aberrations observed for the ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex aberrations, while the linear dose-response term was significantly higher in NBS cells only for simple exchanges. These results point to the importance of the functions of ATM and NBS in chromatin modifications that function to facilitate correct DSB repair and minimize aberration formation. To further understand the sensitivity differences that were observed in ATM and NBS deficient cells, in this study, chromosomal aberration analysis was performed in normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, or Mirin, an MRN complex inhibitor involved in activation of ATM. We are also testing siRNA knockdown of these proteins. Normal and ATM or NBS suppressed cells were irradiated with gamma-rays and chromosomes were collected with a premature chromosome

  8. Another brick in the cell wall: biosynthesis dependent growth model.

    Directory of Open Access Journals (Sweden)

    Adelin Barbacci

    Full Text Available Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper.

  9. Another Brick in the Cell Wall: Biosynthesis Dependent Growth Model

    Science.gov (United States)

    Barbacci, Adelin; Lahaye, Marc; Magnenet, Vincent

    2013-01-01

    Expansive growth of plant cell is conditioned by the cell wall ability to extend irreversibly. This process is possible if (i) a tensile stress is developed in the cell wall due to the coupling effect between turgor pressure and the modulation of its mechanical properties through enzymatic and physicochemical reactions and if (ii) new cell wall elements can be synthesized and assembled to the existing wall. In other words, expansive growth is the result of coupling effects between mechanical, thermal and chemical energy. To have a better understanding of this process, models must describe the interplay between physical or mechanical variable with biological events. In this paper we propose a general unified and theoretical framework to model growth in function of energy forms and their coupling. This framework is based on irreversible thermodynamics. It is then applied to model growth of the internodal cell of Chara corallina modulated by changes in pressure and temperature. The results describe accurately cell growth in term of length increment but also in term of cell pectate biosynthesis and incorporation to the expanding wall. Moreover, the classical growth model based on Lockhart's equation such as the one proposed by Ortega, appears as a particular and restrictive case of the more general growth equation developed in this paper. PMID:24066142

  10. Interaction of Cryptococcus neoformans extracellular vesicles with the cell wall.

    Science.gov (United States)

    Wolf, Julie M; Espadas-Moreno, Javier; Luque-Garcia, Jose L; Casadevall, Arturo

    2014-12-01

    Cryptococcus neoformans produces extracellular vesicles containing a variety of cargo, including virulence factors. To become extracellular, these vesicles not only must be released from the plasma membrane but also must pass through the dense matrix of the cell wall. The greatest unknown in the area of fungal vesicles is the mechanism by which these vesicles are released to the extracellular space given the presence of the fungal cell wall. Here we used electron microscopy techniques to image the interactions of vesicles with the cell wall. Our goal was to define the ultrastructural morphology of the process to gain insights into the mechanisms involved. We describe single and multiple vesicle-leaving events, which we hypothesized were due to plasma membrane and multivesicular body vesicle origins, respectively. We further utilized melanized cells to "trap" vesicles and visualize those passing through the cell wall. Vesicle size differed depending on whether vesicles left the cytoplasm in single versus multiple release events. Furthermore, we analyzed different vesicle populations for vesicle dimensions and protein composition. Proteomic analysis tripled the number of proteins known to be associated with vesicles. Despite separation of vesicles into batches differing in size, we did not identify major differences in protein composition. In summary, our results indicate that vesicles are generated by more than one mechanism, that vesicles exit the cell by traversing the cell wall, and that vesicle populations exist as a continuum with regard to size and protein composition. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  11. Aberrant Expression of Functional BAFF-System Receptors by Malignant B-Cell Precursors Impacts Leukemia Cell Survival

    Science.gov (United States)

    Maia, Sara; Pelletier, Marc; Ding, Jixin; Hsu, Yen-Ming; Sallan, Stephen E.; Rao, Sambasiva P.; Nadler, Lee M.; Cardoso, Angelo A.

    2011-01-01

    Despite exhibiting oncogenic events, patient's leukemia cells are responsive and dependent on signals from their malignant bone marrow (BM) microenvironment, which modulate their survival, cell cycle progression, trafficking and resistance to chemotherapy. Identification of the signaling pathways mediating this leukemia/microenvironment interplay is critical for the development of novel molecular targeted therapies. We observed that primary leukemia B-cell precursors aberrantly express receptors of the BAFF-system, BAFF-R, BCMA, and TACI. These receptors are functional as their ligation triggers activation of NF-κB, MAPK/JNK, and Akt signaling. Leukemia cells express surface BAFF and APRIL ligands, and soluble BAFF is significantly higher in leukemia patients in comparison to age-matched controls. Interestingly, leukemia cells also express surface APRIL, which seems to be encoded by APRIL-δ, a novel isoform that lacks the furin convertase domain. Importantly, we observed BM microenvironmental cells express the ligands BAFF and APRIL, including surface and secreted BAFF by BM endothelial cells. Functional studies showed that signals through BAFF-system receptors impact the survival and basal proliferation of leukemia B-cell precursors, and support the involvement of both homotypic and heterotypic mechanisms. This study shows an unforeseen role for the BAFF-system in the biology of precursor B-cell leukemia, and suggests that the target disruption of BAFF signals may constitute a valid strategy for the treatment of this cancer. PMID:21687682

  12. Aberrant expression of functional BAFF-system receptors by malignant B-cell precursors impacts leukemia cell survival.

    Directory of Open Access Journals (Sweden)

    Sara Maia

    Full Text Available Despite exhibiting oncogenic events, patient's leukemia cells are responsive and dependent on signals from their malignant bone marrow (BM microenvironment, which modulate their survival, cell cycle progression, trafficking and resistance to chemotherapy. Identification of the signaling pathways mediating this leukemia/microenvironment interplay is critical for the development of novel molecular targeted therapies.We observed that primary leukemia B-cell precursors aberrantly express receptors of the BAFF-system, BAFF-R, BCMA, and TACI. These receptors are functional as their ligation triggers activation of NF-κB, MAPK/JNK, and Akt signaling. Leukemia cells express surface BAFF and APRIL ligands, and soluble BAFF is significantly higher in leukemia patients in comparison to age-matched controls. Interestingly, leukemia cells also express surface APRIL, which seems to be encoded by APRIL-δ, a novel isoform that lacks the furin convertase domain. Importantly, we observed BM microenvironmental cells express the ligands BAFF and APRIL, including surface and secreted BAFF by BM endothelial cells. Functional studies showed that signals through BAFF-system receptors impact the survival and basal proliferation of leukemia B-cell precursors, and support the involvement of both homotypic and heterotypic mechanisms.This study shows an unforeseen role for the BAFF-system in the biology of precursor B-cell leukemia, and suggests that the target disruption of BAFF signals may constitute a valid strategy for the treatment of this cancer.

  13. Cotton fiber: a powerful single-cell model for cell wall and celluloseresearch

    Directory of Open Access Journals (Sweden)

    Candace Hope Haigler

    2012-05-01

    Full Text Available Cotton fibers are single-celled extensions of the seed epidermis. They can be isolated in pureform as they undergo staged differentiation including primary cell wall synthesis duringelongation and nearly pure cellulose synthesis during secondary wall thickening. Thiscombination of features supports clear interpretation of data about cell walls and cellulosesynthesis in the context of high throughput modern experimental technologies. Priorcontributions of cotton fiber to building fundamental knowledge about cell walls will besummarized and the dynamic changes in cell wall polymers throughout cotton fiberdifferentiation will be described. Recent successes in using stable cotton transformation to altercotton fiber cell wall properties as well as cotton fiber quality will be discussed. Future prospectsto perform experiments more rapidly through altering cotton fiber wall properties via virusinduced gene silencing will be evaluated.

  14. Growth rate of late passage sarcoma cells is independent of epigenetic events but dependent on the amount of chromosomal aberrations

    International Nuclear Information System (INIS)

    Becerikli, Mustafa; Jacobsen, Frank; Rittig, Andrea; Köhne, Wiebke; Nambiar, Sandeep; Mirmohammadsadegh, Alireza; Stricker, Ingo; Tannapfel, Andrea; Wieczorek, Stefan; Epplen, Joerg Thomas; Tilkorn, Daniel; Steinstraesser, Lars

    2013-01-01

    Soft tissue sarcomas (STS) are characterized by co-participation of several epigenetic and genetic events during tumorigenesis. Having bypassed cellular senescence barriers during oncogenic transformation, the factors further affecting growth rate of STS cells remain poorly understood. Therefore, we investigated the role of gene silencing (DNA promoter methylation of LINE-1, PTEN), genetic aberrations (karyotype, KRAS and BRAF mutations) as well as their contribution to the proliferation rate and migratory potential that underlies “initial” and “final” passage sarcoma cells. Three different cell lines were used, SW982 (synovial sarcoma), U2197 (malignant fibrous histiocytoma (MFH)) and HT1080 (fibrosarcoma). Increased proliferative potential of final passage STS cells was not associated with significant differences in methylation (LINE-1, PTEN) and mutation status (KRAS, BRAF), but it was dependent on the amount of chromosomal aberrations. Collectively, our data demonstrate that these fairly differentiated/advanced cancer cell lines have still the potential to gain an additional spontaneous growth benefit without external influences and that maintenance of increased proliferative potential towards longevity of STS cells (having crossed senescence barriers) may be independent of overt epigenetic alterations. -- Highlights: Increased proliferative potential of late passage STS cells was: • Not associated with epigenetic changes (methylation changes at LINE-1, PTEN). • Not associated with mutation status of KRAS, BRAF. • Dependent on presence/absence of chromosomal aberrations

  15. Growth rate of late passage sarcoma cells is independent of epigenetic events but dependent on the amount of chromosomal aberrations

    Energy Technology Data Exchange (ETDEWEB)

    Becerikli, Mustafa; Jacobsen, Frank; Rittig, Andrea; Köhne, Wiebke [Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum (Germany); Nambiar, Sandeep; Mirmohammadsadegh, Alireza; Stricker, Ingo; Tannapfel, Andrea [Institute of Pathology, Ruhr-University Bochum (Germany); Wieczorek, Stefan; Epplen, Joerg Thomas [Department of Human Genetics, Ruhr-University Bochum (Germany); Tilkorn, Daniel [Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum (Germany); Steinstraesser, Lars, E-mail: lars.steinstraesser@rub.de [Department of Plastic Surgery, BG University Hospital Bergmannsheil, Ruhr-University Bochum (Germany)

    2013-07-15

    Soft tissue sarcomas (STS) are characterized by co-participation of several epigenetic and genetic events during tumorigenesis. Having bypassed cellular senescence barriers during oncogenic transformation, the factors further affecting growth rate of STS cells remain poorly understood. Therefore, we investigated the role of gene silencing (DNA promoter methylation of LINE-1, PTEN), genetic aberrations (karyotype, KRAS and BRAF mutations) as well as their contribution to the proliferation rate and migratory potential that underlies “initial” and “final” passage sarcoma cells. Three different cell lines were used, SW982 (synovial sarcoma), U2197 (malignant fibrous histiocytoma (MFH)) and HT1080 (fibrosarcoma). Increased proliferative potential of final passage STS cells was not associated with significant differences in methylation (LINE-1, PTEN) and mutation status (KRAS, BRAF), but it was dependent on the amount of chromosomal aberrations. Collectively, our data demonstrate that these fairly differentiated/advanced cancer cell lines have still the potential to gain an additional spontaneous growth benefit without external influences and that maintenance of increased proliferative potential towards longevity of STS cells (having crossed senescence barriers) may be independent of overt epigenetic alterations. -- Highlights: Increased proliferative potential of late passage STS cells was: • Not associated with epigenetic changes (methylation changes at LINE-1, PTEN). • Not associated with mutation status of KRAS, BRAF. • Dependent on presence/absence of chromosomal aberrations.

  16. Cadmium chloride strongly enhances cyclophosphamide-induced chromosome aberrations in mouse bone marrow cells

    Energy Technology Data Exchange (ETDEWEB)

    Pandurangarao, V.L.; Blazina, S.; Bherje, R. [Western Michigan Univ., Kalamazoo, MI (United States)] [and others

    1997-10-01

    Earlier we reported that a single 5 mg cadmium chloride (CdCl{sub 2})/kg ip dose enhanced chromosome aberrations (ca) with 50 mg/kg cyclophosphamide (CP) in mouse bone marrow cells. In this report groups of 4 mice were injected ip with saline, 0.31, 0.62, 1.25, 2.5 or 5.0 mg/kg CdCl{sub 2}, followed by saline injections at 24 h. Other mice similarly uninjected at 0 h were injected with 50 mg/kg CP at 24 h. All the mice were injected ip with 4 mg colchicine/kg at 44 h. At 48 h the bone marrow cells were processed for chromosome spreads. After dissection, visual examination revealed obvious internal hemorrhaging of the testes at 1.25 CdCl{sub 2} mg/kg and higher doses. This effect was not further increased by CP treatment. The lowest ca enhancing dose of CdCl{sub 2} on CP was 0.625 mg/kg. Our hypothesis is that Cd replaces zinc presents in numerous DNA repair enzymes and proteins resulting in diminished repair. Subsequently, the excess of unrepaired DNA damage is seen as chromatid breaks, deletions, fragments and exchanges.

  17. A study of the induction of chromosomal aberrations in human breast cancer cells with Californium-252

    Energy Technology Data Exchange (ETDEWEB)

    Byrne, T.E. [Roane State, Harriman, Tennessee (United States); Khan, M.K.; Kabalka, G.W.; MacCabe, J.A.; Miller, L.F. [Univ. of Tennessee, TN (United States); Martin, R.C. [Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States)

    2000-10-01

    A system for testing potential BNCT pharmaceuticals in cell cultures has been developed with the cooperation of Oak Ridge National Laboratory (ORNL), the University of Tennessee Chemistry Department, the University of Tennessee Biochemistry, Cellular and Molecular Biology Department and the University of Tennessee Nuclear Engineering Department. The scope of this research is to build upon the established cellular studies and determine the role of thermalized neutrons from Cf-252 in causing chromosomal aberrations. Following standard laboratory treatment the human breast cancer cell line (ATTC HTB-129, MDA-MB-435s) was exposed to Cf-252 neutron sources provided by the Californium User Facility for Neutron Science at ORNL. The neutron spectrum and beam characteristics are similar to those of reactor fission sources with an average energy of 2.1 MeV. A 50 mg source of Cf-252 moderated by a large mass of water provides a source on the order of 1 x 10{sup 9} thermal neutrons/cm{sup 2}/s at a distance of 3 cm complemented by a larger flux of fast neutrons. The half-life of Cf-252 is 2.65 years, and thus provides a simple and reliable source of neutrons for cancer treatments in locations without suitable nuclear reactors. (author)

  18. Investigation of X-ray-induced chromosome aberrations in 'preleukaemic' mammalian cells

    International Nuclear Information System (INIS)

    Szollar, J.

    1977-01-01

    A study was done on the frequency of numerical and structural aberrations induced by different doses of X-ray irradiation in spontaneously leukaemic AKR mice, compared with the values of healthy control CBA/H-T 6 T 6 mice. Both were irradiated under the same conditions, but their chromosomes were affected in a different way. The number of cells containing aneuploid sets, rings, fragments, or metacentric chromosomes was significantly higher in the 2-month-old AKR mice than in the control CBA group. The increased chromosomal fragility found in AKR bone marrow cells 5-7 months before the manifestation of lymphoid leukaemia might be an important factor in the development of malignant condition. This genetic imbalance could provide a possible reason for an increase of spontaneous malfunction of the cellular system, as well as for an increased sensitivity to external factors. Thus it might be connected directly with the predisposition to malignant growth, or it has an indirect role helping virus activation, or acting together with the immune deficiency, by creating a weaker system that is more sensitive to carcinogenic agents

  19. Gene mutations, chromosome aberrations and survival after X-ray irradiation of cultured Chinese hamster cells at cysteamine protection

    International Nuclear Information System (INIS)

    Elisova, I.V.; Feoktistova, I.P.

    1983-01-01

    The culture of Chinese hamster cells (clone 431) has been used to study cysteamine action on mutagenous effect of X-rays, determined by the induction of resistance of gene mutations to 6-thioguanine and chromosomal abberations, as well as on the reproductive form of death of irradiated cells. Dose--- effect curves are obtained under conditions of irradiation with and without protector. The factor of dose alteration is 2.0 for chromosomal aberrations and cell survival, and 2.8 for gene mutations. It is sUpposed that cysteamine affects the general mechanisms, which take part in the realis zation of injuries that bring about gene mutations, chromosomal aberrations and cell lethality

  20. Bending forces plastically deform growing bacterial cell walls

    Science.gov (United States)

    Amir, Ariel; Babaeipour, Farinaz; McIntosh, Dustin B.; Nelson, David R.; Jun, Suckjoon

    2014-01-01

    Cell walls define a cell’s shape in bacteria. The walls are rigid to resist large internal pressures, but remarkably plastic to adapt to a wide range of external forces and geometric constraints. Currently, it is unknown how bacteria maintain their shape. In this paper, we develop experimental and theoretical approaches and show that mechanical stresses regulate bacterial cell wall growth. By applying a precisely controllable hydrodynamic force to growing rod-shaped Escherichia coli and Bacillus subtilis cells, we demonstrate that the cells can exhibit two fundamentally different modes of deformation. The cells behave like elastic rods when subjected to transient forces, but deform plastically when significant cell wall synthesis occurs while the force is applied. The deformed cells always recover their shape. The experimental results are in quantitative agreement with the predictions of the theory of dislocation-mediated growth. In particular, we find that a single dimensionless parameter, which depends on a combination of independently measured physical properties of the cell, can describe the cell’s responses under various experimental conditions. These findings provide insight into how living cells robustly maintain their shape under varying physical environments. PMID:24711421

  1. Effects of turmeric and its active principle, curcumin, on bleomycin-induced chromosome aberrations in Chinese hamster ovary cells

    OpenAIRE

    Araújo, Maria Cristina P.; Dias, Francisca da Luz; Kronka, Sergio N. [UNESP; Takahashi, Catarina S.

    1999-01-01

    Naturally occurring antioxidants have been extensively studied for their capacity to protect organisms and cells from oxidative damage. Many plant constituents including turmeric and curcumin appear to be potent antimutagens and antioxidants. The effects of turmeric and curcumin on chromosomal aberration frequencies induced by the radiomimetic agent bleomycin (BLM) were investigated in Chinese hamster ovary (CHO) cells. Three concentrations of each drug, turmeric (100, 250 and 500 mg/ml) and ...

  2. Gender differences in the induction of chromosomal aberrations and gene mutations in rodent germ cells

    International Nuclear Information System (INIS)

    Adler, Ilse-Dore; Carere, Angelo; Eichenlaub-Ritter, Ursula; Pacchierotti, Francesca

    2007-01-01

    Germ cell mutagenicity testing provides experimental data to quantify genetic risk for exposed human populations. The majority of tests are performed with exposure of males, and female data are relatively rare. The reason for this paucity lies in the differences between male and female germ cell biology. Male germ cells are produced throughout reproductive life and all developmental stages can be ascertained by appropriate breeding schemes. In contrast, the female germ cell pool is limited, meiosis begins during embryogenesis and oocytes are arrested over long periods of time until maturation processes start for small numbers of oocytes during the oestrus cycle in mature females. The literature data are reviewed to point out possible gender differences of germ cells to exogenous agents such as chemicals or ionizing radiation. From the limited information, it can be concluded that male germ cells are more sensitive than female germ cells to the induction of chromosomal aberrations and gene mutations. However, exceptions are described which shed doubt on the extrapolation of experimental data from male rodents to the genetic risk of the human population. Furthermore, the female genome may be more sensitive to mutation induction during peri-conceptional stages compared to the male genome of the zygote. With few exceptions, germ cell experiments have been carried out under high acute exposure to optimize the effects and to compensate for the limited sample size in animal experiments. Human exposure to environmental agents, on the other hand, is usually chronic and involves low doses. Under these conditions, gender differences may become apparent that have not been studied so far. Additionally, data are reviewed that suggest a false impression of safety when responses are negative under high acute exposure of male rodents while a mutational response is induced by low chronic exposure. The classical (morphological) germ cell mutation tests are not performed anymore

  3. Chromosome and cell wall segregation in Streptococcus faecium ATCC 9790

    Energy Technology Data Exchange (ETDEWEB)

    Higgins, M.L.; Glaser, D.; Dicker, D.T.; Zito, E.T.

    1989-01-01

    Segregation was studied by measuring the positions of autoradiographic grain clusters in chains formed from single cells containing on average less than one radiolabeled chromosome strand. The degree to which chromosomal and cell wall material cosegregated was quantified by using the methods of S. Cooper and M. Weinberger, dividing the number of chains labeled at the middle. This analysis indicated that in contrast to chromosomal segregation in Escherichia coli and, in some studies, to that in gram-positive rods, chromosomal segregation in Streptococcus faecium was slightly nonrandom and did not vary with growth rate. Results were not significantly affected by strand exchange. In contrast, labeled cell wall segregated predominantly nonrandomly.

  4. Chromosomal aberration

    International Nuclear Information System (INIS)

    Ishii, Yutaka

    1988-01-01

    Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G 2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G 2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G 2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G 1 phase. (author)

  5. Penium margaritaceum as a model organism for cell wall analysis of expanding plant cells

    DEFF Research Database (Denmark)

    Rydahl, Maja Gro; Fangel, Jonatan Ulrik; Mikkelsen, Maria Dalgaard

    2015-01-01

    organization of the polymeric networks of the cell wall around the protoplast also contributes to the direction of growth, the shape of the cell, and the proper positioning of the cell in a tissue. In essence, plant cell expansion represents the foundation of development. Most studies of plant cell expansion......The growth of a plant cell encompasses a complex set of subcellular components interacting in a highly coordinated fashion. Ultimately, these activities create specific cell wall structural domains that regulate the prime force of expansion, internally generated turgor pressure. The precise...... mechanics of the cell wall in a single plant cell....

  6. Purification and characterization of a soybean cell wall protein

    International Nuclear Information System (INIS)

    San Francisco, S.; Tierney, M.L.

    1989-01-01

    Plant cell wall composition is thought to reflect cellular responses to developmental and environmental signals. We have purified a 33 kDa protein from cell wall extracts of soybean seedlings which is most abundant in extracts from the hook region of the hypocotyl and is rich in proline and hydroxypyroline. In vivo 3 H-proline labelling of hypocotyl tissues indicates that the hook tissue is the predominant site for synthesis of this protein. In unwounded hook, label is incorporated into a 33 kDa protein, while in wounded hook this and additional proteins rich in proline are synthesized. Similarly treated cell wall extracts analyzed by Western blot analysis, using a polyclonal antibody raised against this 33kD protein, showed that the 33 kDa protein is most abundant in cell wall extracts from the hook region of unwounded seedlings and does not increase upon wounding. An immunologically related 35kD protein is also apparent in extracts from wounded hooks and appears to co-migrate with one of the labelled proteins extractable from this tissue. These data indicate that there are two related, proline-rich cell wall proteins in the hook region of soybean seedlings, one of which (33 kDa) is prominent during seedling development and another (35 kDa) which is wound inducible

  7. The role of the cell wall in plant immunity

    Directory of Open Access Journals (Sweden)

    Frederikke Gro eMalinovsky

    2014-05-01

    Full Text Available The battle between plants and microbes is evolutionarily ancient, highly complex and often co-dependent. A primary challenge for microbes is to breach the physical barrier of host cell walls whilst avoiding detection by the plant’s immune receptors. While some receptors sense conserved microbial features, others monitor physical changes caused by an infection attempt. Detection of microbes leads to activation of appropriate defense responses that then challenge the attack. Plant cell walls are formidable and dynamic barriers. They are constructed primarily of complex carbohydrates joined by numerous distinct connection types, and are subject to extensive post-synthetic modification to suit prevailing local requirements. Multiple changes can be triggered in cell walls in response to microbial attack. Some of these are well described, but many remain obscure. The study of the myriad of subtle processes underlying cell wall modification poses special challenges for plant glycobiology. In this review we describe the major molecular and cellular mechanisms that underlie the roles of cell walls in plant defense against pathogen attack. In so doing, we also highlight some of the challenges inherent in studying these interactions, and briefly describe the analytical potential of molecular probes used in conjunction with carbohydrate microarray technology.

  8. Cell-wall composition and the grouping antigens of Streptococci.

    Science.gov (United States)

    SLADE, H D; SLAMP, W C

    1962-08-01

    Slade, Hutton D. (Northwestern University Medical School, Chicago, Ill.) and William C. Slamp. Cell-wall composition and grouping antigens of streptococci. J. Bacteriol. 84:345-351. 1962.-The carbohydrates present in the cell walls of streptococci belonging to serological groups A-H and K-S, and unclassifiable strains, have been identified. The sugars found were rhamnose, glucose, galactose, arabinose, and mannose. All sugars vary considerably in their distribution among the groups; glucose, galactose, and rhamnose occur most frequently. Strains were found which contained each of the latter sugars singly or in combination with one or both of the other sugars. Variation within a single group occurred in one-half of the groups. A strain containing only glucose and another only galactose were found. Except for groups A and C, in which only rhamnose is present in the great majority of strains, the presence or absence of the sugars does not aid in the identification of the groups. The cell walls of all groups examined also contained alanine, glutamic acid, lysine, glucosamine, galactosamine, and muramic acid. The cell walls of all groups, except D, agglutinated in the presence of specific group antisera, indicating the presence of the group antigen in the cell wall. Strains in groups F, K, and M gave a weak reaction. The structure and chemical composition of the group antigens of the streptococci are discussed.

  9. Cell wall proteins of Aquaspirillum serpens.

    Science.gov (United States)

    Koval, S F; Murray, R G

    1981-06-01

    The Triton X-100-insoluble wall fraction of Aquaspirillum serpens VHA contained three major proteins: the regularly structured (RS) superficial protein (molecular weight 140,000) and two peptidoglycan-associated proteins (molecular weights, 32,000 and 33,000). The molecular arrangement and interactions of the outer membrane and RS proteins were examined with the use of bifunctional cross-linking reagents. The peptidoglycan-associated and RS proteins were not readily cross-linked in either homo- or heteropolymers. This suggests that the free amino groups are not suitably disposed for cross-linking. Some high-molecular-weight multimers of the RS protein were produced, but the subunit structure of the RS array was not stabilized by cross-linking. The peptidoglycan-associated proteins were cross-linked to high-molecular-weight multimers, but no dimers or trimers were produced. This result suggests that these proteins exist in the outer membrane as multimers larger than trimers.

  10. Aberrant expression of cell cycle and material metabolism related genes contributes to hepatocellular carcinoma occurrence.

    Science.gov (United States)

    Yan, Hongxian; Li, Zhaohui; Shen, Quan; Wang, Qian; Tian, Jianguo; Jiang, Qingfeng; Gao, Linbo

    2017-04-01

    This study aims to deepen our understanding of the molecular mechanism underlying the occurrence of hepatocellular carcinoma (HCC). We first downloaded a gene expression profile dataset GSE29721 (10 HCC and 10 control samples) from Gene Expression Omnibus database (http://www.ncbi.nlm.nih.gov/geo/). Differentially expressed genes (DEGs) were identified by the paired t-test using limma package. Pathway and functional enrichment analyses were performed with DAVID tools. Transcription factors were annotated with TRANSFAC database and tumor associated genes (TAGs) were annotated with TAG and TSGene databases. Protein-protein interaction (PPI) network was conducted using STRING online tool and function module was further identified with BioNet package. Totally, 527 up-regulated DEGs and 587 down-regulated DEGs were identified. GO functional and KEGG pathway enrichment analyses showed that the up-regulated DEGs were mainly related to cell division and cell cycle, while the down-regulated DEGs were largely related to material metabolism, especially secondary metabolism. Proteins encoded by DEGs CDK1, BUB1, CDC20, NCAPG, NDC80, CDCA8, MAD2L1, CCNB1, CCNA2 and BIRC5 were hub genes with high degrees in the PPI network; further module analysis detected a subnetwork consisting of 55 proteins, such as CYP2B6, ACAA1, BHMT and ALDH2. Taken together, aberrant expression of cell cycle related genes (e.g., CDK1, CCNA2, CCNB1, BUB1, MAD2L1 and CDC20) and material metabolism related genes (e.g., CYP2B6, ACAA1, BHMT and ALDH2) may contribute to HCC occurrence. Copyright © 2017 Elsevier GmbH. All rights reserved.

  11. Cell wall staining with Trypan blue enables quantitative analysis of morphological changes in yeast cells

    DEFF Research Database (Denmark)

    Liesche, Johannes; Marek, Magdalena; Günther-Pomorski, Thomas

    2015-01-01

    staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall...... with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain...

  12. Pectic homogalacturonan masks abundant sets of xyloglucan epitopes in plant cell walls

    DEFF Research Database (Denmark)

    Marcus, Susan E; Verhertbruggen, Yves; Hervé, Cécile

    2008-01-01

    BACKGROUND: Molecular probes are required to detect cell wall polymers in-situ to aid understanding of their cell biology and several studies have shown that cell wall epitopes have restricted occurrences across sections of plant organs indicating that cell wall structure is highly developmentally...... is associated with pectin in plant cell walls. They also indicate that documented patterns of cell wall epitopes in relation to cell development and cell differentiation may need to be re-considered in relation to the potential masking of cell wall epitopes by other cell wall components....... regulated. Xyloglucan is the major hemicellulose or cross-linking glycan of the primary cell walls of dicotyledons although little is known of its occurrence or functions in relation to cell development and cell wall microstructure. RESULTS: Using a neoglycoprotein approach, in which a XXXG heptasaccharide...

  13. Histochemical effects of γ radiation on soft fruit cell walls

    International Nuclear Information System (INIS)

    Foa, E.; Jona, R.; Vallania, R.

    1980-01-01

    Irradiation effects in peaches, tomatoes, cherries and grapes on the composition of cell wall polysaccharides were investigated by histochemical techniques. Cell wall polysaccharides, separated by a modified Jensen's method were pectins, hemicellulose, non-cellulosic polysaccharides and cellulose. The extinction values of Periodic Acid Schiff stained tissues was measured by microscopical photometry. Irradiation induced highly significant changes in polysaccharide composition of mesocarp cell walls; these changes were found to be a function of time of irradiation after harvest and of the species tested. A general influence on polysaccharide molecules was not found. Variations produced by irradiation are postulated to be an interference with a regulatory system rather than a breakdown of a functional molecule (metabolic enzyme or polysaccharide. (author)

  14. Cell wall integrity signalling in human pathogenic fungi.

    Science.gov (United States)

    Dichtl, Karl; Samantaray, Sweta; Wagener, Johannes

    2016-09-01

    Fungi are surrounded by a rigid structure, the fungal cell wall. Its plasticity and composition depend on active regulation of the underlying biosynthesis and restructuring processes. This involves specialised signalling pathways that control gene expression and activities of biosynthetic enzymes. The cell wall integrity (CWI) pathway is the central signalling cascade required for the adaptation to a wide spectrum of cell wall perturbing conditions, including heat, oxidative stress and antifungals. In the recent years, great efforts were made to analyse the CWI pathway of diverse fungi. It turned out that the CWI signalling cascade is mostly conserved in the fungal kingdom. In this review, we summarise as well as compare the current knowledge on the canonical CWI pathway in the human pathogenic fungi Candida albicans, Candida glabrata, Aspergillus fumigatus and Cryptococcus neoformans. Understanding the differences and similarities in the stress responses of these organisms could become a key to improving existing or developing new antifungal therapies. © 2016 John Wiley & Sons Ltd.

  15. Analysis of chromosomal aberrations, micronuclei and hematological disorders among workers of wireless communication instruments and cell phone (Mobile) users

    International Nuclear Information System (INIS)

    Eldawy, H.A.; Khattab, F.I.; Hassan, N.H.A.; Amin, Y.M.; Mahmoud, M.M.A.

    2003-01-01

    This study was carried out to investigate the hazardous effect of electromagnetic radiation (EMR) such as chromosomal aberration, disturbed micronucleus formation and hematological disorders that may detected among workers of wireless communication instruments and mobile phone users. Seven individuals ( 3 males and 4 females) of a central workers in the microwave unit of the wireless station and 7 users of Mobil phone (4 males and 3 females ) were volunteered to give blood samples. Chromosomes and micronucleus were prepared for cytogenetic analysis as well as blood film for differential count. The results obtained in the microwave group indicated that, the total summation of all types of aberrations (chromosomes and chromatid aberrations) had a frequency of 6. 14% for the exposed group, whereas, the frequency in the control group amounted to 1.57%. In Mobil phone users, the total summation of all types of aberrations(chromosome and chromatid aberrations) had a frequency of 4.43% for the exposed group and 1.71% for the control group. The incidence of the total number of micronuclei in the exposed microwave group was increased 4.3 folds as compared with those of the control group The incidence of the total number of micronuclei in the exposed mobile phone group was increased 2 fold as compared with those in the control group. On the other hand, normal ranges of total white blood cells counts were determined for mobile phone users but abnormalities in the differential counts of the different types of the white blood cells such as neutropenia, eosinophilia and lymphocytosis were observed in the individuals number 1,2,3,7 in microwave group

  16. Cellulose synthesis in two secondary cell wall processes in a single cell type.

    Science.gov (United States)

    Mendu, Venugopal; Stork, Jozsef; Harris, Darby; DeBolt, Seth

    2011-11-01

    Plant cells have a rigid cell wall that constrains internal turgor pressure yet extends in a regulated and organized manner to allow the cell to acquire shape. The primary load-bearing macromolecule of a plant cell wall is cellulose, which forms crystalline microfibrils that are organized with respect to a cell's function and shape requirements. A primary cell wall is deposited during expansion whereas secondary cell wall is synthesized post expansion during differentiation. A complex form of asymmetrical cellular differentiation occurs in Arabidopsis seed coat epidermal cells, where we have recently shown that two secondary cell wall processes occur that utilize different cellulose synthase (CESA) proteins. One process is to produce pectinaceous mucilage that expands upon hydration and the other is a radial wall thickening that reinforced the epidermal cell structure. Our data illustrate polarized specialization of CESA5 in facilitating mucilage attachment to the parent seed and CESA2, CESA5 and CESA9 in radial cell wall thickening and formation of the columella. Herein, we present a model for the complexity of cellulose biosynthesis in this highly differentiated cell type with further evidence supporting each cellulosic secondary cell wall process.

  17. Novel insights of ethylene role in strawberry cell wall metabolism.

    Science.gov (United States)

    Villarreal, Natalia M; Marina, María; Nardi, Cristina F; Civello, Pedro M; Martínez, Gustavo A

    2016-11-01

    Due to its organoleptic and nutraceutical qualities, strawberry fruit (Fragaria x ananassa, Duch) is a worldwide important commodity. The role of ethylene in the regulation of strawberry cell wall metabolism was studied in fruit from Toyonoka cultivar harvested at white stage, when most changes associated with fruit ripening have begun. Fruit were treated with ethephon, an ethylene-releasing reagent, or with 1-methylcyclopropene (1-MCP), a competitive inhibitor of ethylene action, maintaining a set of non-treated fruit as controls for each condition. Ethephon treated-fruit showed higher contents of hemicelluloses, cellulose and neutral sugars regarding controls, while 1-MCP-treated fruit showed a lower amount of those fractions. On the other hand, ethephon-treated fruit presented a lower quantity of galacturonic acid from ionically and covalently bound pectins regarding controls, while 1-MCP-treated fruit showed higher contents of those components. We also explored the ethylene effect over the mRNA accumulation of genes related to pectins and hemicelluloses metabolism, and a relationship between gene expression patterns and cell wall polysaccharides contents was shown. Moreover, we detected that strawberry necrotrophic pathogens growth more easily on plates containing cell walls from ethephon-treated fruit regarding controls, while a lower growth rate was observed when cell walls from 1-MCP treated fruit were used as the only carbon source, suggesting an effect of ethylene on cell wall structure. Around 60% of strawberry cell wall is made up of pectins, which in turns is 70% made by homogalacturonans. Our findings support the idea of a central role for pectins on strawberry fruit softening and a participation of ethylene in the regulation of this process. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. A zoom into the nanoscale texture of secondary cell walls.

    Science.gov (United States)

    Keplinger, Tobias; Konnerth, Johannes; Aguié-Béghin, Véronique; Rüggeberg, Markus; Gierlinger, Notburga; Burgert, Ingo

    2014-01-10

    Besides classical utilization of wood and paper, lignocellulosic biomass has become increasingly important with regard to biorefinery, biofuel production and novel biomaterials. For these new applications the macromolecular assembly of cell walls is of utmost importance and therefore further insights into the arrangement of the molecules on the nanolevel have to be gained. Cell wall recalcitrance against enzymatic degradation is one of the key issues, since an efficient degradation of lignocellulosic plant material is probably the most crucial step in plant conversion to energy. A limiting factor for in-depth analysis is that high resolution characterization techniques provide structural but hardly chemical information (e.g. Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM)), while chemical characterization leads to a disassembly of the cell wall components or does not reach the required nanoscale resolution (Fourier Tranform Infrared Spectroscopy (FT-IR), Raman Spectroscopy). Here we use for the first time Scanning Near-Field Optical Microscopy (SNOM in reflection mode) on secondary plant cell walls and reveal a segmented circumferential nanostructure. This pattern in the 100 nm range was found in the secondary cell walls of a softwood (spruce), a hardwood (beech) and a grass (bamboo) and is thus concluded to be consistent among various plant species. As the nanostructural pattern is not visible in classical AFM height and phase images it is proven that the contrast is not due to changes in surfaces topography, but due to differences in the molecular structure. Comparative analysis of model substances of casted cellulose nanocrystals and spin coated lignin indicate, that the SNOM signal is clearly influenced by changes in lignin distribution or composition. Therefore and based on the known interaction of lignin and visible light (e.g. fluorescence and resonance effects), we assume the elucidated nanoscale structure to reflect variations in

  19. Evolution of the cell wall components during terrestrialization

    Directory of Open Access Journals (Sweden)

    Alicja Banasiak

    2014-12-01

    Full Text Available Colonization of terrestrial ecosystems by the first land plants, and their subsequent expansion and diversification, were crucial for the life on the Earth. However, our understanding of these processes is still relatively poor. Recent intensification of studies on various plant organisms have identified the plant cell walls are those structures, which played a key role in adaptive processes during the evolution of land plants. Cell wall as a structure protecting protoplasts and showing a high structural plasticity was one of the primary subjects to changes, giving plants the new properties and capabilities, which undoubtedly contributed to the evolutionary success of land plants. In this paper, the current state of knowledge about some main components of the cell walls (cellulose, hemicelluloses, pectins and lignins and their evolutionary alterations, as preadaptive features for the land colonization and the plant taxa diversification, is summarized. Some aspects related to the biosynthesis and modification of the cell wall components, with particular emphasis on the mechanism of transglycosylation, are also discussed. In addition, new surprising discoveries related to the composition of various cell walls, which change how we perceive their evolution, are presented, such as the presence of lignin in red algae or MLG (1→3,(1→4-β-D-glucan in horsetails. Currently, several new and promising projects, regarding the cell wall, have started, deciphering its structure, composition and metabolism in the evolutionary context. That additional information will allow us to better understand the processes leading to the terrestrialization and the evolution of extant land plants.

  20. Yeast cell wall chitin reduces wine haze formation.

    Science.gov (United States)

    Ndlovu, Thulile; Divol, Benoit; Bauer, Florian F

    2018-04-27

    Protein haze formation in bottled wines is a significant concern for the global wine industry and wine clarification before bottling is therefore a common but expensive practice. Previous studies have shown that wine yeast strains can reduce haze formation through the secretion of certain mannoproteins, but it has been suggested that other yeast-dependent haze protective mechanisms exist. On the other hand, addition of chitin has been shown to reduce haze formation, likely because grape chitinases have been shown to be the major contributors to haze. In this study, Chardonnay grape must fermented by various yeast strains resulted in wines with different protein haze levels indicating differences in haze protective capacities of the strains. The cell wall chitin levels of these strains were determined, and a strong correlation between cell wall chitin levels and haze protection capability was observed. To further evaluate the mechanism of haze protection, Escherichia coli -produced GFP-tagged grape chitinase was shown to bind efficiently to yeast cell walls in a cell wall chitin concentration-dependent manner, while commercial chitinase was removed from synthetic wine in quantities also correlated with the cell wall chitin levels of the strains. Our findings suggest a new mechanism of reducing wine haze, and propose a strategy for optimizing wine yeast strains to improve wine clarification. Importance In this study, we establish a new mechanism by which wine yeast strains can impact on the protein haze formation of wines, and demonstrate that yeast cell wall chitin binds grape chitinase in a chitin-concentration dependent manner. We also show that yeast can remove this haze-forming protein from wine. Chitin has in the past been shown to efficiently reduce wine haze formation when added to the wine in high concentration as a clarifying agent. Our data suggest that the selection of yeast strains with high levels of cell wall chitin can reduce protein haze. We also

  1. Novel Enzymes for Targeted Hydrolysis of Algal Cell Walls

    DEFF Research Database (Denmark)

    Schultz-Johansen, Mikkel

    urchins are known algae-eaters and may therefore be inhabited by endosymbiotic bacteria that help in degradation of algal cell wall constituents. This thesis work investigated bacteria associated with seaweed, seagrass and sea urchins for their enzymatic activities against algal cell wall polysaccharides....... These enzymes degraded fucoidan extracted from brown algae of the order Fucales, but displayed individual substrate preference and degradation pattern. This work adds substantial information to a protein family which is largely undiscovered to date. Several of the enzyme activities discovered in this thesis...

  2. The role of the cell wall in plant immunity

    DEFF Research Database (Denmark)

    Malinovsky, Frederikke Gro; Fangel, Jonatan Ulrik; Willats, William George Tycho

    2014-01-01

    The battle between plants and microbes is evolutionarily ancient, highly complex, and often co-dependent. A primary challenge for microbes is to breach the physical barrier of host cell walls whilst avoiding detection by the plant's immune receptors. While some receptors sense conserved microbial...... features, others monitor physical changes caused by an infection attempt. Detection of microbes leads to activation of appropriate defense responses that then challenge the attack. Plant cell walls are formidable and dynamic barriers. They are constructed primarily of complex carbohydrates joined...

  3. Aberrant expression of long noncoding RNAs in cumulus cells isolated from PCOS patients.

    Science.gov (United States)

    Huang, Xin; Hao, Cuifang; Bao, Hongchu; Wang, Meimei; Dai, Huangguan

    2016-01-01

    To describe the long noncoding RNA (lncRNA) profiles in cumulus cells isolated from polycystic ovary syndrome (PCOS) patients by employing a microarray and in-depth bioinformatics analysis. This information will help us understand the occurrence and development of PCOS. In this study, we used a microarray to describe lncRNA profiles in cumulus cells isolated from ten patients (five PCOS and five normal women). Several differentially expressed lncRNAs were chosen to validate the microarray results by quantitative RT-PCR (qRT-PCR). Then, the differentially expressed lncRNAs were classified into three subgroups (HOX loci lncRNA, enhancer-like lncRNA, and lincRNA) to deduce their potential features. Furthermore, a lncRNA/mRNA co-expression network was constructed by using the Cytoscape software (V2.8.3, http://www.cytoscape.org/ ). We observed that 623 lncRNAs and 260 messenger RNAs (mRNAs) were significantly up- or down-regulated (≥2-fold change), and these differences could be used to discriminate cumulus cells of PCOS from those of normal patients. Five differentially expressed lncRNAs (XLOC_011402, ENST00000454271, ENST00000433673, ENST00000450294, and ENST00000432431) were selected to validate the microarray results using quantitative RT-PCR (qRT-PCR). The qRT-PCR results were consistent with the microarray data. Further analysis indicated that many differentially expressed lncRNAs were transcribed from chromosome 2 and may act as enhancers to regulate their neighboring protein-coding genes. Forty-three lncRNAs and 29 mRNAs were used to construct the coding-non-coding gene co-expression network. Most pairs positively correlated, and one mRNA correlated with one or more lncRNAs. Our study is the first to determine genome-wide lncRNA expression patterns in cumulus cells isolated from PCOS patients by microarray. The results show that clusters of lncRNAs were aberrantly expressed in cumulus cells of PCOS patients compared with those of normal women, which revealed

  4. Interactions of Condensed Tannins with Saccharomyces cerevisiae Yeast Cells and Cell Walls: Tannin Location by Microscopy.

    Science.gov (United States)

    Mekoue Nguela, Julie; Vernhet, Aude; Sieczkowski, Nathalie; Brillouet, Jean-Marc

    2015-09-02

    Interactions between grape tannins/red wine polyphenols and yeast cells/cell walls was previously studied within the framework of red wine aging and the use of yeast-derived products as an alternative to aging on lees. Results evidenced a quite different behavior between whole cells (biomass grown to elaborate yeast-derived products, inactivated yeast, and yeast inactivated after autolysis) and yeast cell walls (obtained from mechanical disruption of the biomass). Briefly, whole cells exhibited a high capacity to irreversibly adsorb grape and wine tannins, whereas only weak interactions were observed for cell walls. This last point was quite unexpected considering the literature and called into question the real role of cell walls in yeasts' ability to fix tannins. In the present work, tannin location after interactions between grape and wine tannins and yeast cells and cell walls was studied by means of transmission electron microscopy, light epifluorescence, and confocal microscopy. Microscopy observations evidenced that if tannins interact with cell walls, and especially cell wall mannoproteins, they also diffuse freely through the walls of dead cells to interact with their plasma membrane and cytoplasmic components.

  5. A correlative study on the frequencies of radiation-induced chromosome aberrations in somatic and germ cells of mammals

    International Nuclear Information System (INIS)

    Buul, P.P.W. van

    1976-01-01

    A series of investigations on the correlation between the frequencies of radiation-induced chromosome aberrations in somatic and germ cells of mouse and rhesus monkey is described. In the mouse the induction of reciprocal translocations in bone-marrow cells was compared with that in spermatogonia (as scored in the descending spermatocytes). In the rhesus monkey frequencies of radiation-induced chromosome aberrations in spermatogonia and peripheral blood lymphocytes were studied. Furthermore the effect of multigeneration irradiation (69 generations with 200 rads X-rays) on the sensitivity for translocation induction in spermatogonia of male mice was studied. Frequencies of dicentric chromosomes and chromosomal deletions in cultured peripheral blood lymphocytes of 5 different types of mice were determined following in vitro irradiation with doses of 100 and/or 200 rad X-rays. To obtain more insight into the processes underlying translocation induction in spermatogonia of the mouse, fractionation experiments were conducted

  6. Bacterial Cell Wall Growth, Shape and Division

    NARCIS (Netherlands)

    Derouaux, A.; Terrak, M.; den Blaauwen, T.; Vollmer, W.; Remaut, H.; Fronzes, R.

    2014-01-01

    The shape of a bacterial cell is maintained by its peptidoglycan sacculus that completely surrounds the cytoplasmic membrane. During growth the sacculus is enlarged by peptidoglycan synthesis complexes that are controlled by components linked to the cytoskeleton and, in Gram-negative bacteria, by

  7. Extraction of proteins from yeast cell wall

    African Journals Online (AJOL)

    USER

    2010-05-24

    May 24, 2010 ... Figure 2. The UV absorption spectrum of extracted proteins. Startup Foundation of Chongqing Normal University (No. 07XLB025), and Natural Science Foundation Project of. CQ CSTC (No. CSTC, 2009BB5238) China. REFERENCES. Cabib E, Roh DH, Schmidt M, Crotti LB, Varma A (2001). The yeast cell.

  8. Molecular mechanisms for vascular development and secondary cell wall formation

    Directory of Open Access Journals (Sweden)

    Jung Hyun eYang

    2016-03-01

    Full Text Available Vascular tissues are important for transporting water and nutrients throughout the plant and as physical support of upright growth. The primary constituents of vascular tissues, xylem and phloem, are derived from the meristematic vascular procambium and cambium. Xylem cells develop secondary cell walls that form the largest part of plant lignocellulosic biomass that serve as a renewable feedstock for biofuel production. For the last decade, research on vascular development and secondary cell wall biosynthesis has seen rapid progress due to the importance of these processes to plant biology and to the biofuel industry. Plant hormones, transcriptional regulators and peptide signaling regulate procambium/cambium proliferation, vascular patterning, and xylem differentiation. Transcriptional regulatory pathways play a pivot role in secondary cell wall biosynthesis. Although most of these discoveries are derived from research in Arabidopsis, many genes have shown conserved functions in biofuel feedstock species. Here, we review the recent advances in our understanding of vascular development and secondary cell wall formation and discuss potential biotechnological uses.

  9. Longevity in vivo of primary cell wall cellulose synthases.

    Science.gov (United States)

    Hill, Joseph Lee; Josephs, Cooper; Barnes, William J; Anderson, Charles T; Tien, Ming

    2018-02-01

    Our work focuses on understanding the lifetime and thus stability of the three main cellulose synthase (CESA) proteins involved in primary cell wall synthesis of Arabidopsis. It had long been thought that a major means of CESA regulation was via their rapid degradation. However, our studies here have uncovered that AtCESA proteins are not rapidly degraded. Rather, they persist for an extended time in the plant cell. Plant cellulose is synthesized by membrane-embedded cellulose synthase complexes (CSCs). The CSC is composed of cellulose synthases (CESAs), of which three distinct isozymes form the primary cell wall CSC and another set of three isozymes form the secondary cell wall CSC. We determined the stability over time of primary cell wall (PCW) CESAs in Arabidopsis thaliana seedlings, using immunoblotting after inhibiting protein synthesis with cycloheximide treatment. Our work reveals very slow turnover for the Arabidopsis PCW CESAs in vivo. Additionally, we show that the stability of all three CESAs within the PCW CSC is altered by mutations in individual CESAs, elevated temperature, and light conditions. Together, these results suggest that CESA proteins are very stable in vivo, but that their lifetimes can be modulated by intrinsic and environmental cues.

  10. Aberrant TAL1 activation is mediated by an interchromosomal interaction in human T-cell acute lymphoblastic leukemia.

    Science.gov (United States)

    Patel, B; Kang, Y; Cui, K; Litt, M; Riberio, M S J; Deng, C; Salz, T; Casada, S; Fu, X; Qiu, Y; Zhao, K; Huang, S

    2014-02-01

    Long-range chromatin interactions control metazoan gene transcription. However, the involvement of intra- and interchromosomal interactions in development and oncogenesis remains unclear. TAL1/SCL is a critical transcription factor required for the development of all hematopoietic lineages; yet, aberrant TAL1 transcription often occurs in T-cell acute lymphoblastic leukemia (T-ALL). Here, we report that oncogenic TAL1 expression is regulated by different intra- and interchromosomal loops in normal hematopoietic and leukemic cells, respectively. These intra- and interchromosomal loops alter the cell-type-specific enhancers that interact with the TAL1 promoter. We show that human SET1 (hSET1)-mediated H3K4 methylations promote a long-range chromatin loop, which brings the +51 enhancer in close proximity to TAL1 promoter 1 in erythroid cells. The CCCTC-binding factor (CTCF) facilitates this long-range enhancer/promoter interaction of the TAL1 locus in erythroid cells while blocking the same enhancer/promoter interaction of the TAL1 locus in human T-cell leukemia. In human T-ALL, a T-cell-specific transcription factor c-Maf-mediated interchromosomal interaction brings the TAL1 promoter into close proximity with a T-cell-specific regulatory element located on chromosome 16, activating aberrant TAL1 oncogene expression. Thus, our study reveals a novel molecular mechanism involving changes in three-dimensional chromatin interactions that activate the TAL1 oncogene in human T-cell leukemia.

  11. Ability of root canal antiseptics used in dental practice to induce chromosome aberrations in human dental pulp cells.

    Science.gov (United States)

    Nishimura, Hiroyuki; Higo, Yukari; Ohno, Maki; Tsutsui, Takeo W; Tsutsui, Takeki

    2008-01-08

    Root canal antiseptics are topically applied to root canals within the pulpless teeth to treat the root canal and periapical infections. Because the antiseptics that are applied to root canals can penetrate through dentin or leak out through an apical foramen into the periodontium and distribute by the systemic circulation, it is important to study the safety of these antiseptics. In the present study, we examined the ability to induce chromosome aberrations in human dental pulp cells of five root canal antiseptics, namely, carbol camphor (CC), camphorated p-monochlorophenol (CMCP), formocresol (FC), calcium hydroxide, and iodoform which are most commonly used in dental practice. Statistically significant increases in the levels of chromosome aberrations were induced by CC, FC, or iodoform in a concentration-dependent manner. Conversely, CMCP and calcium hydroxide failed to induce chromosome aberrations in the absence or presence of exogenous metabolic activation. The percentages of cells with polyploid or endoreduplication were enhanced by FC or iodoform. Our results indicate that the root canal antiseptics that exhibited a positive response are potentially genotoxic to human cells.

  12. Relationship of DNA repair and chromosome aberrations to potentially lethal damage repair in X-irradiated mammalian cells

    International Nuclear Information System (INIS)

    Fornace, A.J. Jr.; Nagasawa, H.; Little, J.B.

    1980-01-01

    By the alkaline elution technique, the repair of x-ray-induced DNA single strand breaks and DNA-protein cross-links was investigated in stationary phase, contact-inhibited mouse cells. During the first hour of repair, approximately 90% of x-ray induced single strand breaks were rejoined whereas most of the remaining breaks were rejoined more slowly during the next 5 h. The number of residual non-rejoined single strand breaks was approximately proportional to the x-ray dose at early repair times. DNA-protein cross-links were removed at a slower rate - T 1/2 approximately 10 to 12 h. Cells were subcultured at low density at various times after irradiation and scored for colony survival, and chromosome aberrations in the first mitosis after sub-culture. Both cell lethality and the frequency of chromosome aberrations decreased during the first several hours of repair, reaching a minimum level by 6 h; this decrease correlated temporally with the repair of the slowly rejoining DNA strand breaks. The possible relationship of DNA repair to changes in survival and chromosome aberrations is discussed

  13. High resistance of fibroblasts from Mongolian gerbil embryos to cell killing and chromosome aberrations by X-irradiation

    International Nuclear Information System (INIS)

    Suzuki, F.; Nakao, N.; Nikaido, O.; Kondo, S.

    1992-01-01

    Mongolian gerbil (Meriones unguiculatus) is known to be one of the most radioresistant animal species. In order to determine whether there is any correlation between mortality of mammals exposed to γ- or X-rays and radiation sensitivity of culture cells derived from different mammalian species, we have examined the X-ray survival curves of normal diploid fibroblasts from Mongolian gerbil embryos and compared with those of other cultured embryo cells from various laboratory animals and normal human. There was a big difference in cell survival to X-rays among different mammalian species. The D 0 values of Mongolian gerbil cells ranged from 2.3 to 2.6 Gy which are twice as high as those of human cells. The mean D 0 value of human cells was 1.1 Gy. Mouse, rat, Chinese hamster and Syrian/golden hamster cells showed similar D 0 values ranging from 1.7 to 2.0 Gy. When cells were irradiated with 2 Gy of X-rays, three times longer mitotic delay was observed in human cells than in Mongolian gerbil cells. At this X-ray dose, furthermore, ten times more chromosome aberrations were detected in human cells than in Mongolian gerbil cells, and the frequencies of other rodent cells lay between the values for the two cell strains. These data indicate that the Mongolian gerbil cells are resistant to X-ray-induced cell killing and chromosome aberrations, and that radiation sensitivity of primarily cultured mammalian cells may be reflected by their radioresistance in vivo. (author)

  14. O-acetylation of Plant Cell Wall Polysaccharides

    Directory of Open Access Journals (Sweden)

    Sascha eGille

    2012-01-01

    Full Text Available Plant cell walls are composed of structurally diverse polymers, many of which are O-acetylated. How plants O-acetylate wall polymers and what its function is remained elusive until recently, when two protein families were identified in the model plant Arabidopsis that are involved in the O-acetylation of wall polysaccharides – the reduced wall acetylation (RWA and the trichome birefringence-like (TBL proteins. This review discusses the role of these two protein families in polysaccharide O-acetylation and outlines the differences and similarities of polymer acetylation mechanisms in plants, fungi, bacteria and mammals. Members of the TBL protein family had been shown to impact pathogen resistance, freezing tolerance, and cellulose biosynthesis. The connection of TBLs to polysaccharide O-acetylation thus gives crucial leads into the biological function of wall polymer O-acetylation.From a biotechnological point understanding the O-acetylation mechanism is important as acetyl-substituents inhibit the enzymatic degradation of wall polymers and released acetate can be a potent inhibitor in microbial fermentations, thus impacting the economic viability of e.g. lignocellulosic based biofuel production.

  15. Titanium biomaterials with complex surfaces induced aberrant peripheral circadian rhythms in bone marrow mesenchymal stromal cells.

    Science.gov (United States)

    Hassan, Nathaniel; McCarville, Kirstin; Morinaga, Kenzo; Mengatto, Cristiane M; Langfelder, Peter; Hokugo, Akishige; Tahara, Yu; Colwell, Christopher S; Nishimura, Ichiro

    2017-01-01

    Circadian rhythms maintain a high level of homeostasis through internal feed-forward and -backward regulation by core molecules. In this study, we report the highly unusual peripheral circadian rhythm of bone marrow mesenchymal stromal cells (BMSCs) induced by titanium-based biomaterials with complex surface modifications (Ti biomaterial) commonly used for dental and orthopedic implants. When cultured on Ti biomaterials, human BMSCs suppressed circadian PER1 expression patterns, while NPAS2 was uniquely upregulated. The Ti biomaterials, which reduced Per1 expression and upregulated Npas2, were further examined with BMSCs harvested from Per1::luc transgenic rats. Next, we addressed the regulatory relationship between Per1 and Npas2 using BMSCs from Npas2 knockout mice. The Npas2 knockout mutation did not rescue the Ti biomaterial-induced Per1 suppression and did not affect Per2, Per3, Bmal1 and Clock expression, suggesting that the Ti biomaterial-induced Npas2 overexpression was likely an independent phenomenon. Previously, vitamin D deficiency was reported to interfere with Ti biomaterial osseointegration. The present study demonstrated that vitamin D supplementation significantly increased Per1::luc expression in BMSCs, though the presence of Ti biomaterials only moderately affected the suppressed Per1::luc expression. Available in vivo microarray data from femurs exposed to Ti biomaterials in vitamin D-deficient rats were evaluated by weighted gene co-expression network analysis. A large co-expression network containing Npas2, Bmal1, and Vdr was observed to form with the Ti biomaterials, which was disintegrated by vitamin D deficiency. Thus, the aberrant BMSC peripheral circadian rhythm may be essential for the integration of Ti biomaterials into bone.

  16. Cell cycle aberration in ameloblastoma and adenomatoid odontogenic tumor: As evidenced by the expression of p53 and survivin.

    Science.gov (United States)

    Shaikh, Zulfin; Niranjan, K C

    2015-01-01

    p53 and survivin are involved in cell cycle progression and inhibition of apoptosis, respectively. Survivin is a unique protein which functions in progression of cell division and inhibits apoptosis leading to cell proliferation and cell survival. According to the literature, mutation of p53 leads to promotion of survivin function. Thus, the importance of cell cycle aberration and uncontrolled proliferation resulting from mutation of p53 and up-regulation of survivin is discussed. To assess the role of p53 and survivin in ameloblastoma and adenomatoid odontogenic tumor (AOT). The percentages of positive tumor cells were considered for statistical evaluation. Nuclear labeling index for p53 and nuclear, cytoplasmic and combined labeling index for survivin was obtained from the stained slides. Immunohistochemical expression of p53 and survivin was done qualitatively and quantitatively in 25 cases each of ameloblastoma and AOT. Mann-Whitney U-test, Wilcoxon signed ranks test and Pearson's correlation test. Quantitatively, p53 and survivin expression was statistically significant in AOT (P = 0.003) and qualitatively, in ameloblastoma (P = 0.004). Survivin expression was significant (P = 0.002) between the study groups unlike that of p53 (P = 0.554). There was no much difference in p53 expression in ameloblastoma and AOT suggestive of cell cycle aberration in both the odontogenic tumors, but significant difference in survivin expression in ameloblastoma and AOT with higher percentage of positive cells in ameloblastoma may be indicative of an aggressive behavior of ameloblastoma.

  17. Effect of salinity in the first phase of salt stress on leaf cell-wall components of maize with special reference to cell-wall extensibility

    OpenAIRE

    Uddin, Md. Nesar

    2012-01-01

    Summary of Experiment 2 A method of cell-wall isolation was optimized, and cell walls were separated into two fractions (250-405 µm fraction and > 405 µm fraction). Both the cell-wall fractions showed negative color test with iodine reagent and thus were free from starch content. Cellulose, neutral sugars and uronic acid responses due to the salt treatment were obvious from the 250-405 µm cell-wall fraction. On the other hand, the > 405 µm cell-wall fraction did not show much variation i...

  18. Effect of nutrient calcium on the cell wall composition and ...

    African Journals Online (AJOL)

    The effect of calcium in the nutrient medium on kikuyu grass (Pennisetum clandestinum Hochst), grown in a solution culture, was investigated. Calcium had no effect on the lignin content of leaf material, but decreased the lignin content per unit stem cell wall. Calcium appeared to have no significant effect on either the ...

  19. Characterisation of cell-wall polysaccharides from mandarin segment membranes

    NARCIS (Netherlands)

    Coll-Almela, L.; Saura-Lopez, D.; Laencina-Sanchez, J.; Schols, H.A.; Voragen, A.G.J.; Ros-García, J.M.

    2015-01-01

    In an attempt to develop a process of enzymatic peeling of mandarin segments suitable for use on an industrial scale, the cell wall fraction of the segment membrane of Satsuma mandarin fruits was extracted to obtain a chelating agent-soluble pectin fraction (ChSS), a dilute sodium hydroxide-soluble

  20. Parenchyma cell wall structure in twining stem of Dioscorea balcanica

    Czech Academy of Sciences Publication Activity Database

    Radosavljević, J.S.; Pristov, J.B.; Mitrović, A.Lj.; Steinbach, Gabor; Mouille, G.; Tufegdžić, S.; Maksimović, V.; Mutavdžić, D.; Janošević, D.; Vuković, M.; Garab, G.; Radotić, K.

    2017-01-01

    Roč. 24, č. 11 (2017), s. 4653-4669 ISSN 0969-0239 R&D Projects: GA MŠk(CZ) ED2.1.00/19.0392 Institutional support: RVO:61388971 Keywords : Cell wall * Cellulose fibril order * Dioscorea balcanica Kosanin Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 3.417, year: 2016

  1. In planta modification of the potato tuber cell wall

    NARCIS (Netherlands)

    Oomen, R.J.F.J.

    2003-01-01

    Apart from its well known uses in the human diet a large amount of the grown potatoes (about one third in the Netherlands) is used for the isolation of starch which is used in several food and non-food applications. The cell wall fibres comprise a large portion of the waste material remaining

  2. New Model of Wood Cell Wall Microfibril and Its Implications

    Science.gov (United States)

    Umesh P. Agarwal; Sally A. Ralph; Rick S. Reiner; Carlos Baez

    2015-01-01

    Traditionally it has been accepted that the cell walls are made up of microfibrils which are partly crystalline. However, based on the recently obtained Raman evidence that showed that the interior of the microfibril was significantly disordered and water accessible, a new model is proposed. In this model, the molecular chains of cellulose are still organized along the...

  3. Structure of cellulose microfibrils in primary cell walls from Collenchyma

    Czech Academy of Sciences Publication Activity Database

    Thomas, L. H.; Forsyth, V. T.; Šturcová, Adriana; Kennedy, C. J.; May, R. P.; Altaner, C. M.; Apperley, D. C.; Wess, T. J.; Jarvis, M. C.

    2013-01-01

    Roč. 161, č. 1 (2013), s. 465-476 ISSN 0032-0889 R&D Projects: GA ČR GAP108/12/0703 Institutional support: RVO:61389013 Keywords : primary cell wall * cellulose microfibril structure * chain packing disorder Subject RIV: CD - Macromolecular Chemistry Impact factor: 7.394, year: 2013

  4. Anatomical changes in the cell-wall structure of Leucaena ...

    African Journals Online (AJOL)

    The structural changes in the cell wall and delignification pattern caused by Trametes versicolor and Trametes hirsuta in the sap wood of Leucaena leucocephala were examined by light and confocal laser scanning microscopy. The in vitro decay test was conducted for 12 weeks. Both species of Trametes used in this study ...

  5. Variability in Biochemical Composition and Cell Wall Constituents ...

    African Journals Online (AJOL)

    Samples were analyzed for their biochemical composition - starch, amylose, amylopectin, total sugars, reducing sugars and non-reducing sugars along the head, middle and tail regions of each tuber using standard analytical methods. Cell wall constituents - acid detergent fibre, neutral detergent fibre, acid detergent lignin, ...

  6. Polymer mobility in cell walls of cucumber hypocotyls

    Science.gov (United States)

    Fenwick, K. M.; Apperley, D. C.; Cosgrove, D. J.; Jarvis, M. C.

    1999-01-01

    Cell walls were prepared from the growing region of cucumber (Cucumis sativus) hypocotyls and examined by solid-state 13C NMR spectroscopy, in both enzymically active and inactivated states. The rigidity of individual polymer segments within the hydrated cell walls was assessed from the proton magnetic relaxation parameter, T2, and from the kinetics of cross-polarisation from 1H to 13C. The microfibrils, including most of the xyloglucan in the cell wall, as well as cellulose, behaved as very rigid solids. A minor xyloglucan fraction, which may correspond to cross-links between microfibrils, shared a lower level of rigidity with some of the pectic galacturonan. Other pectins, including most of the galactan side-chain residues of rhamnogalacturonan I, were much more mobile and behaved in a manner intermediate between the solid and liquid states. The only difference observed between the enzymically active and inactive cell walls, was the loss of a highly mobile, methyl-esterified galacturonan fraction, as the result of pectinesterase activity.

  7. Methods for the preparation of cell walls from potatoes

    NARCIS (Netherlands)

    Jardine, W.G.; Doeswijk-Voragen, C.H.L.; MacKinnon, I.M.R.; Broek, van den L.A.M.; Ha, M.A.; Jarvis, C.; Voragen, A.G.J.

    2002-01-01

    A group of new methods is described for preparing cell walls from potatoes and processed potato products. Starting from raw domestic potatoes, starch is degraded enzymatically after a very brief 100 °C gelatinisation step conducted after homogenisation to minimise the time required for heat

  8. Chromosomal aberrations induced by caffeine, 3H-thymidine and by X-rays in two L5178Y sublines of different radiosensitivity. Part 1. Chromosomal aberrations in cells treated with 2mM caffeine and tritiated thymidine

    International Nuclear Information System (INIS)

    Bocian, E.; Bouzyk, E.; Rosiek, O.; Ziemba-Zoltowska, B.

    1982-01-01

    Chromosomal aberrations were studied in two sublines of L5178Y cells with different sensitivity to X-rays. Cells were treated with 2 mM caffeine for 12 h. Then they were examined at various time intervals from 5 to 24 h. Caffeine caused over three times more aberrations, mainly chromatid breaks and gaps, in radiation-sensitive L5178Y-S than in radiation-resistant L5178Y-R cells. The maximum frequency of chromatid breaks in both sublines was found at 8 h and that of chromatid exchanges and isochromatid breaks at 12 h after treatment. A dramatic decrease of the frequency of all types of aberrations at 24 h was observed. In the pulse labelled experiments caffeine enhanced the frequency of aberrations that were induced by 3 H-thymidine at a concentration of 1 μCi/ml. This effect of caffeine was greater in L5178Y-R than in L5178Y-S cells. (author)

  9. Gamma induced chromosomal aberrations in meristem cells of cotton hybrids and their parental forms

    International Nuclear Information System (INIS)

    Kraevoj, S.Ya.; Akhmedova, M.M.; Amirkulov, D.

    1977-01-01

    The effect of gamma quanta on the first mitoses in the small roots of cotton hybrids and their parents results in different frequency of chromosome rearrangements in them. It has been proved that the frequency of chromosome aberrations is different in hybrids and different varieties of cotton. With increase in irradiation doses (from 10 to 30 kR) the frequency of chromosome aberrations goes up in all varieties and hybrids studies. The type of chromosome rearrangements in hybrids and their parents depends on the irradiation dose

  10. Spontaneous and induced chromosomal aberrations in bone ma-row cells of mice of different strain and age

    International Nuclear Information System (INIS)

    Lil'p, J.G.; Korogodina, Yu.V.

    1981-01-01

    The sensitivity of bone marrow cell chromosomes both to an alkylating agent thiophosphamide and #betta#-irradiation in 101/H, A/He, CBA, BALB/c and C57BL/6 aging mice has been studied. Changes in the sensitivity of bone marrow cell chromosomes with age are shown to depend both on mutagenic effect type and animal's genotype. The age dependent yield of chromosomal aberrations did not change in mice of all studied strains after #betta#-irradiation under conditions of our experiments. After the thiophosphamide effect, an increased sensitivity of bone marrow cell chromosomes was observed in the old 101/H, A/He and CBA mice as compared to the young ones. The level of induced chromosomal aberrations in C57BL/6 mice did not vary with age. Cells exhibiting multiple damages to chromosomes accurred in the bone marrow following the thiophosphamide effect. An increased sensitivity of old animals of certain strains resulted mainly from a sharp numerical growth of such cells. No increase in the number of cells in intact animals of all strains related to age dependent chromosomal structural damages was observed, whereas the accumulation of aneuploid cells probably depended on the genotype

  11. Ultrastructure and composition of the Nannochloropsis gaditana cell wall.

    Science.gov (United States)

    Scholz, Matthew J; Weiss, Taylor L; Jinkerson, Robert E; Jing, Jia; Roth, Robyn; Goodenough, Ursula; Posewitz, Matthew C; Gerken, Henri G

    2014-11-01

    Marine algae of the genus Nannochloropsis are promising producers of biofuel precursors and nutraceuticals and are also harvested commercially for aquaculture feed. We have used quick-freeze, deep-etch electron microscopy, Fourier transform infrared spectroscopy, and carbohydrate analyses to characterize the architecture of the Nannochloropsis gaditana (strain CCMP 526) cell wall, whose recalcitrance presents a significant barrier to biocommodity extraction. The data indicate a bilayer structure consisting of a cellulosic inner wall (~75% of the mass balance) protected by an outer hydrophobic algaenan layer. Cellulase treatment of walls purified after cell lysis generates highly enriched algaenan preparations without using the harsh chemical treatments typically used in algaenan isolation and characterization. Nannochloropsis algaenan was determined to comprise long, straight-chain, saturated aliphatics with ether cross-links, which closely resembles the cutan of vascular plants. Chemical identification of >85% of the isolated cell wall mass is detailed, and genome analysis is used to identify candidate biosynthetic enzymes. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  12. Method for determining solutes in the cell walls of leaves.

    Science.gov (United States)

    Bernstein, L

    1971-03-01

    A perfusion method is described whereby large discs of amphistomatous leaves are vacuum-perfused with water so that either successive fractions of perfusate may be analyzed for solutes or the infused water may be displaced and collected after equilibration with the leaf cells. With castor bean leaves, estimates of electrolyte concentration in cell wall water by the two methods were similar. Total electrolytes in leaf cell wall water of castor beans (Ricinus communis), sunflower (Helianthus annuus), and cabbage (Brassica oleracea capitata) from nonsaline cultures were about 2, 2, and 10 milliequivalents per liter, respectively, increasing to 4, 10, and 30 milliequivalents per liter under saline conditions. Electrolytes recovered in successive fractions were similar in composition, and continuous perfusion resulted in a steady release of solutes, the concentration in the perfusate varying inversely with the perfusion rate. Diffusional release of solutes from cells was less than expected at low perfusion rates, suggesting that solute reabsorption may increase as solute concentration in the perfusate increases with decreased perfusion rates. Perfusate concentration and composition were essentially unaffected by temperature (2 and 23 C) or by perfusing with 0.5 mm CaSO(4) rather than with water. Electrolytes in perfusates on an equivalent basis were Ca(2+), 30%; Mg(2+), 10%; and Na(+) + K(+), 60%, the proportions of sodium increasing from 10 to 50% in leaves (cabbage) that accumulated sodium under saline conditions. Salinity (added NaCl) of the root culture medium caused a 3- to 5-fold increase in total cell wall electrolyte concentration, but this amounted to an increase from less than 1 or a few per cent to no more than 7% (in cabbage) of the cell sap electrolyte concentrations. Solutes in the cell wall appear to be in dynamic equilibrium with intracellular solutes.

  13. Low doses of UVB or UVA induce chromosomal aberrations in cultured human skin cells

    NARCIS (Netherlands)

    Emri, G.; Wenczl, E.; Erp, P. van; Jans, J.; Roza, L.; Horkay, I.; Schothorst, A.A.

    2000-01-01

    Chromosomal defects are frequently present in malignant and premalignant skin disorders; however, it is not known whether ultraviolet radiation from sunlight plays a role in their induction. To obtain information on the ability of ultraviolet A and ultraviolet B to induce chromosomal aberrations,

  14. Cell wall staining with Trypan Blue enables quantitative analysis of morphological changes in yeast cells

    Directory of Open Access Journals (Sweden)

    Johannes eLiesche

    2015-02-01

    Full Text Available Yeast cells are protected by a cell wall that plays an important role in the exchange of substances with the environment. The cell wall structure is dynamic and can adapt to different physiological states or environmental conditions. For the investigation of morphological changes, selective staining with fluorescent dyes is a valuable tool. Furthermore, cell wall staining is used to facilitate sub-cellular localization experiments with fluorescently-labeled proteins and the detection of yeast cells in non-fungal host tissues. Here, we report staining of Saccharomyces cerevisiae cell wall with Trypan Blue, which emits strong red fluorescence upon binding to chitin and yeast glucan; thereby, it facilitates cell wall analysis by confocal and super-resolution microscopy. The staining pattern of Trypan Blue was similar to that of the widely used UV-excitable, blue fluorescent cell wall stain Calcofluor White. Trypan Blue staining facilitated quantification of cell size and cell wall volume when utilizing the optical sectioning capacity of a confocal microscope. This enabled the quantification of morphological changes during growth under anaerobic conditions and in the presence of chemicals, demonstrating the potential of this approach for morphological investigations or screening assays.

  15. Reduced Wall Acetylation Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis

    DEFF Research Database (Denmark)

    Manabe, Yuzuki; Verhertbruggen, Yves; Gille, Sascha

    2013-01-01

    The Reduced Wall Acetylation (RWA) proteins are involved in cell wall acetylation in plants. Previously, we described a single mutant, rwa2, which has about 20% lower level of O-acetylation in leaf cell walls and no obvious growth or developmental phenotype. In this study, we generated double......, triple, and quadruple loss-of-function mutants of all four members of the RWA family in Arabidopsis (Arabidopsis thaliana). In contrast to rwa2, the triple and quadruple rwa mutants display severe growth phenotypes revealing the importance of wall acetylation for plant growth and development...

  16. Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption

    OpenAIRE

    Luo, Ying; Wang, Jianguo; Liu, Bin; Wang, Zhouli; Yuan, Yahong; Yue, Tianli

    2015-01-01

    The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin ...

  17. Identification of Cell Wall Synthesis Regulatory Genes Controlling Biomass Characteristics and Yield in Rice (Oryza Sativa)

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Zhaohua PEng [Mississippi State University; Ronald, Palmela [UC-Davis; Wang, Guo-Liang [The Ohio State University

    2013-04-26

    This project aims to identify the regulatory genes of rice cell wall synthesis pathways using a cell wall removal and regeneration system. We completed the gene expression profiling studies following the time course from cell wall removal to cell wall regeneration in rice suspension cells. We also completed, total proteome, nuclear subproteome and histone modification studies following the course from cell wall removal and cell wall regeneration process. A large number of differentially expressed regulatory genes and proteins were identified. Meanwhile, we generated RNAi and over-expression transgenic rice for 45 genes with at least 10 independent transgenic lines for each gene. In addition, we ordered T-DNA and transposon insertion mutants for 60 genes from Korea, Japan, and France and characterized the mutants. Overall, we have mutants and transgenic lines for over 90 genes, exceeded our proposed goal of generating mutants for 50 genes. Interesting Discoveries a) Cell wall re-synthesis in protoplasts may involve a novel cell wall synthesis mechanism. The synthesis of the primary cell wall is initiated in late cytokinesis with further modification during cell expansion. Phragmoplast plays an essential role in cell wall synthesis. It services as a scaffold for building the cell plate and formation of a new cell wall. Only one phragmoplast and one new cell wall is produced for each dividing cell. When the cell wall was removed enzymatically, we found that cell wall re-synthesis started from multiple locations simultaneously, suggesting that a novel mechanism is involved in cell wall re-synthesis. This observation raised many interesting questions, such as how the starting sites of cell wall synthesis are determined, whether phragmoplast and cell plate like structures are involved in cell wall re-synthesis, and more importantly whether the same set of enzymes and apparatus are used in cell wall re-synthesis as during cytokinesis. Given that many known cell wall

  18. Al-induced root cell wall chemical components differences of wheat ...

    African Journals Online (AJOL)

    Root growth is different in plants with different levels of Al-tolerance under Al stress. Cell wall chemical components of root tip cell are related to root growth. The aim of this study was to explore the relationship between root growth difference and cell wall chemical components. For this purpose, the cell wall chemical ...

  19. Pectic arabinan side chains are essential for pollen cell wall integrity during pollen development

    NARCIS (Netherlands)

    Cankar, K.; Kortstee, A.J.; Toonen, M.A.J.; Wolters-Arts, M.; Houbein, R.; Mariani, C.; Ulvskov, P.; Jorgensen, B.; Schols, H.A.; Visser, R.G.F.; Trindade, L.M.

    2014-01-01

    Pectin is a complex polysaccharide and an integral part of the primary plant cell wall and middle lamella, contributing to cell wall mechanical strength and cell adhesion. To understand the structure–function relationships of pectin in the cell wall, a set of transgenic potato lines with altered

  20. Targeted and non-targeted effects in cell wall polysaccharides from transgenetically modified potato tubers

    NARCIS (Netherlands)

    Huang, J.H.

    2016-01-01

    The plant cell wall is a chemically complex network composed mainly of polysaccharides. Cell wall polysaccharides surround and protect plant cells and are responsible for the stability and rigidity of plant tissue. Pectin is a major component of primary cell wall and the middle lamella of plants.

  1. Targeted and non-targeted effects in cell wall polysaccharides from transgenetically modified potato tubers

    NARCIS (Netherlands)

    Huang, J.H.

    2016-01-01

    The plant cell wall is a chemically complex network composed mainly of polysaccharides. Cell wall polysaccharides surround and protect plant cells and are responsible for the stability and rigidity of plant tissue. Pectin is a major component of primary cell wall and the middle lamella of plants.

  2. Pectic arabinan side chains are essential for pollen cell wall integrity during pollen development

    DEFF Research Database (Denmark)

    Cankar, Katarina; Kortstee, Anne; Toonen, Marcel A.J.

    2014-01-01

    Pectin is a complex polysaccharide and an integral part of the primary plant cell wall and middle lamella, contributing to cell wall mechanical strength and cell adhesion. To understand the structure-function relationships of pectin in the cell wall, a set of transgenic potato lines with altered...

  3. Branched Pectic Galactan in Phloem-Sieve-Element Cell Walls: Implications for Cell Mechanics.

    Science.gov (United States)

    Torode, Thomas A; O'Neill, Rachel; Marcus, Susan E; Cornuault, Valérie; Pose, Sara; Lauder, Rebecca P; Kračun, Stjepan K; Rydahl, Maja Gro; Andersen, Mathias C F; Willats, William G T; Braybrook, Siobhan A; Townsend, Belinda J; Clausen, Mads H; Knox, J Paul

    2018-02-01

    A major question in plant biology concerns the specification and functional differentiation of cell types. This is in the context of constraints imposed by networks of cell walls that both adhere cells and contribute to the form and function of developing organs. Here, we report the identification of a glycan epitope that is specific to phloem sieve element cell walls in several systems. A monoclonal antibody, designated LM26, binds to the cell wall of phloem sieve elements in stems of Arabidopsis ( Arabidopsis thaliana ), Miscanthus x giganteus , and notably sugar beet ( Beta vulgaris ) roots where phloem identification is an important factor for the study of phloem unloading of Suc. Using microarrays of synthetic oligosaccharides, the LM26 epitope has been identified as a β-1,6-galactosyl substitution of β-1,4-galactan requiring more than three backbone residues for optimized recognition. This branched galactan structure has previously been identified in garlic ( Allium sativum ) bulbs in which the LM26 epitope is widespread throughout most cell walls including those of phloem cells. Garlic bulb cell wall material has been used to confirm the association of the LM26 epitope with cell wall pectic rhamnogalacturonan-I polysaccharides. In the phloem tissues of grass stems, the LM26 epitope has a complementary pattern to that of the LM5 linear β-1,4-galactan epitope, which is detected only in companion cell walls. Mechanical probing of transverse sections of M x giganteus stems and leaves by atomic force microscopy indicates that phloem sieve element cell walls have a lower indentation modulus (indicative of higher elasticity) than companion cell walls. © 2018 The author(s). All Rights Reserved.

  4. Through pore diameter in the cell wall of Chara corallina.

    Science.gov (United States)

    Berestovsky, G N; Ternovsky, V I; Kataev, A A

    2001-06-01

    Determination of pore size of the cell wall of Chara corallina has been made by using the polyethylene glycol (PEG) series as the hydrophilic probing molecules. In these experiments, the polydispersity of commercial preparation of PEGs was allowed for. The mass share (gamma(p)) of polyethylene glycol preparation fractions penetrating through the pores was determined using a cellular 'ghost', i.e. fragments of internodal cell walls filled with a 25% solution of non-penetrating PEG 6000 and tied up at the ends. In water, such a 'ghost' developed a hydrostatic pressure close to the cell turgor which persisted for several days. The determination of gamma(p), for polydisperse polyethylene glycols with different average molecular mass (M) was calculated from the degree of pressure restoration after water was replaced by a 5-10% polymer solution. Pressure was recorded using a dynamometer, which measures, in the quasi-isometric mode, the force necessary for the partial compression of the 'ghost' in its small fragment. By utilizing the data on the distribution of PEG 1000, 1450, 2000, and 3350 fractions over molecular mass (M), it was found that gamma(p), for these polyethylene glycols corresponded to the upper limit of ML=800-1100 D (hydrodynamic radius of molecules, r(h)=0.85-1.05 nm). Thus, the effective diameter of the pores in the cell wall of Chara did not exceed 2.1 nm.

  5. Analysis of the soluble cell wall proteome of gymnosperms.

    Science.gov (United States)

    Uzal, Esther Novo; Gómez-Ros, Laura V; Hernández, Jose A; Pedreño, María A; Cuello, Juan; Ros Barceló, Alfonso

    2009-05-15

    We analyzed the cell wall proteome of lignifying suspension cell cultures (SCCs) from four gymnosperms that differ in evolution degree. This analysis showed the presence of "peptide sequence tags" (PSTs) corresponding to glucan endo-1,3-beta-D-glucosidase, xyloglucan-endotrans-glucosylase/hydrolase, chitinases, thaumatin-like proteins and proteins involved in lignin/lignan biosynthesis, such as dirigent-like proteins and peroxidases. Surprisingly, and given the abundance of peroxidases in the cell wall proteome of these gymnosperms, PSTs corresponding to peroxidases were only detected in tryptic fragments of the cell wall proteome of Cycas revoluta. The current lack of knowledge regarding C. revoluta peroxidases led us to purify, characterize and partially sequence the peroxidases responsible for lignin biosynthesis in this species. This yielded three peroxidase-enriched fractions: CrPrx 1, CrPrx 2 and CrPrx 3. Analyses of tryptic peptides of CrPrx 2 (32kDa) and CrPrx 3 (26kDa) suggest that CrPrx 3 arises from CrPrx 2 by protein truncation, and that CrPrx 3 apparently constitutes a post-translational modification of CrPrx 2. That CrPrx 2 and CrPrx 3 are apparently the same enzyme was also deduced from the similarity between the k(cat) shown by both peroxidases for the three monolignols. These results emphasize the analogies between the cell wall proteome of gymnosperms and angiosperms, the complexity of the peroxidase proteome, and the difficulties involved in establishing fine structure-function relationships.

  6. Involvement of aberrant DNA methylation on reduced expression of lysophosphatidic acid receptor-1 gene in rat tumor cell lines

    International Nuclear Information System (INIS)

    Tsujiuchi, Toshifumi; Shimizu, Kyoko; Onishi, Mariko; Sugata, Eriko; Fujii, Hiromasa; Mori, Toshio; Honoki, Kanya; Fukushima, Nobuyuki

    2006-01-01

    Lysophosphatidic acid (LPA) is a bioactive phospholipid that stimulates cell proliferation, migration, and protects cells from apoptosis. It interacts with specific G protein-coupled transmembrane receptors. Recently, it has been reported that alterations of LPA receptor expression might be important in the malignant transformation of tumor cells. Therefore, to assess an involvement of DNA methylation in reduced expression of the LPA receptor-1 (lpa1) gene, we investigated the expression of the lpa1 gene and its DNA methylation patterns in rat tumor cell lines. Both rat brain-derived neuroblastoma B103 and liver-derived hepatoma RH7777 cells used in this study indicated no expression of lpa1. For the analysis of methylation status, bisulfite sequencing was performed with B103 and RH7777 cells, comparing with other lpa1 expressed cells and normal tissues of brain and liver. The lpa1 expressed cells and tissues were all unmethylated in this region of lpa1. In contrast, both B103 and RH7777 cells were highly methylated, correlating with reduced expression of the lpa1. Treatment with 5-aza 2'-deoxycytidine induced expression of lpa1 gene in B103 and RH7777 cells after 24 h. In RH7777 cells treated with 5-aza 2'-deoxycytidine, stress fiber formation was also observed in response to LPA in RH7777 cells, but not in untreated RH7777 cells. These results suggest that aberrant DNA methylation of the lpa1 gene may be involved in its reduced expression in rat tumor cells

  7. Expression of a fungal ferulic acid esterase in suspension cultures of tall fescue (Festuca arundinacea) decreases cell wall feruloylation and increases rates of cell wall digestion.

    Science.gov (United States)

    Morris, Phillip; Dalton, Sue; Langdon, Tim; Hauck, Barbara; de Buanafina, Marcia M O

    2017-01-01

    In the cell walls of grasses ferulic acid is esterified to arabinosyl residues in arabinoxylans that can then undergo oxidative coupling reactions to form ferulate dehydrodimers, trimers and oligomers which function to cross-link cell-wall polysaccharides, limiting cell wall degradability. Fungal ferulic acid esterase can release both esterified monomeric and dimeric ferulic acids from these cell wall arabinoxylans making the cell wall more susceptible to further enzymatic attack and increasing cell wall degradability. Non-embryogenic cell suspension cultures of Festuca arundinacea expressing a Aspergillus niger ferulic acid esterase ( faeA ) targeted to either the apoplast, or endoplasmic reticulum under the control of a constitutive actin promoter, or to the vacuole under the control of a soybean heat shock promoter, were established and FAE activity determined in the cells and medium during a growth cycle. Analysis of the ester-linked ferulates of the cell walls showed that all three transformed cell lines had both reduced ferulate levels and increased levels of xylanase mediated release of wall phenolics on autodigestion as well as increased rates of cell wall digestion in a simulated rumen environment, when compared to control non-transformed cells.

  8. Pea border cell maturation and release involve complex cell wall structural dynamics

    DEFF Research Database (Denmark)

    Mravec, Jozef; Guo, Xiaoyuan; Hansen, Aleksander Riise

    2017-01-01

    of hydrolytic activities, transmission electron microscopy (TEM) and immunolocalization of cell wall components. Using this integrated glycobiology approach, we identified multiple novel modes of cell wall structural and compositional rearrangement during root cap growth and the release of border cells. Our......The adhesion of plant cells is vital for support and protection of the plant body and is maintained by a variety of molecular associations between cell wall components. In some specialized cases though, plant cells are programmed to detach and root cap-derived border cells are examples of this....... Border cells (in some species known as border-like cells) provide an expendable barrier between roots and the environment. Their maturation and release is an important but poorly characterized cell separation event. To gain a deeper insight into the complex cellular dynamics underlying this process, we...

  9. Single-Walled Carbon Nanotubes in Solar Cells.

    Science.gov (United States)

    Jeon, Il; Matsuo, Yutaka; Maruyama, Shigeo

    2018-01-22

    Photovoltaics, more generally known as solar cells, are made from semiconducting materials that convert light into electricity. Solar cells have received much attention in recent years due to their promise as clean and efficient light-harvesting devices. Single-walled carbon nanotubes (SWNTs) could play a crucial role in these devices and have been the subject of much research, which continues to this day. SWNTs are known to outperform multi-walled carbon nanotubes (MWNTs) at low densities, because of the difference in their optical transmittance for the same current density, which is the most important parameter in comparing SWNTs and MWNTs. SWNT films show semiconducting features, which make SWNTs function as active or charge-transporting materials. This chapter, consisting of two sections, focuses on the use of SWNTs in solar cells. In the first section, we discuss SWNTs as a light harvester and charge transporter in the photoactive layer, which are reviewed chronologically to show the history of the research progress. In the second section, we discuss SWNTs as a transparent conductive layer outside of the photoactive layer, which is relatively more actively researched. This section introduces SWNT applications in silicon solar cells, organic solar cells, and perovskite solar cells each, from their prototypes to recent results. As we go along, the science and prospects of the application of solar cells will be discussed.

  10. Cell wall bound anionic peroxidases from asparagus byproducts.

    Science.gov (United States)

    Jaramillo-Carmona, Sara; López, Sergio; Vazquez-Castilla, Sara; Jimenez-Araujo, Ana; Rodriguez-Arcos, Rocio; Guillen-Bejarano, Rafael

    2014-10-08

    Asparagus byproducts are a good source of cationic soluble peroxidases (CAP) useful for the bioremediation of phenol-contaminated wastewaters. In this study, cell wall bound peroxidases (POD) from the same byproducts have been purified and characterized. The covalent forms of POD represent >90% of the total cell wall bound POD. Isoelectric focusing showed that whereas the covalent fraction is constituted primarily by anionic isoenzymes, the ionic fraction is a mixture of anionic, neutral, and cationic isoenzymes. Covalently bound peroxidases were purified by means of ion exchange chromatography and affinity chromatography. In vitro detoxification studies showed that although CAP are more effective for the removal of 4-CP and 2,4-DCP, anionic asparagus peroxidase (AAP) is a better option for the removal of hydroxytyrosol (HT), the main phenol present in olive mill wastewaters.

  11. Roles of tRNA in cell wall biosynthesis

    DEFF Research Database (Denmark)

    Dare, Kiley; Ibba, Michael

    2012-01-01

    responsible for cell wall modifications, aminoacyl-phosphatidylglycerol synthases (aaPGSs) and Fem, were discovered some time ago, they have recently become of intense interest for their roles in the antimicrobial resistance of pathogenic microorganisms. The addition of positively charged amino acids...... to phosphatidylglycerol (PG) by aaPGSs neutralizes the lipid bilayer making the bacteria less susceptible to positively charged antimicrobial agents. Fem transferases utilize aa-tRNA to form peptide bridges that link strands of peptidoglycan. These bridges vary among the bacterial species in which they are present...... and play a role in resistance to antibiotics that target the cell wall. Additionally, the formation of truncated peptides results in shorter peptide bridges and loss of branched linkages which makes bacteria more susceptible to antimicrobials. A greater understanding of the structure and substrate...

  12. DNAM-1 mediates epithelial cell-specific cytotoxicity of aberrant intraepithelial lymphocyte lines from refractory celiac disease type II patients.

    Science.gov (United States)

    Tjon, Jennifer M-L; Kooy-Winkelaar, Yvonne M C; Tack, Greetje J; Mommaas, A Mieke; Schreurs, Marco W J; Schilham, Marco W; Mulder, Chris J; van Bergen, Jeroen; Koning, Frits

    2011-06-01

    In refractory celiac disease (RCD), intestinal epithelial damage persists despite a gluten-free diet. Characteristic for RCD type II (RCD II) is the presence of aberrant surface TCR-CD3(-) intraepithelial lymphocytes (IELs) that can progressively replace normal IELs and eventually give rise to overt lymphoma. Therefore, RCD II is considered a malignant condition that forms an intermediate stage between celiac disease (CD) and overt lymphoma. We demonstrate in this study that surface TCR-CD3(-) IEL lines isolated from three RCD II patients preferentially lyse epithelial cell lines. FACS analysis revealed that DNAM-1 was strongly expressed on the three RCD cell lines, whereas other activating NK cell receptors were not expressed on all three RCD cell lines. Consistent with this finding, cytotoxicity of the RCD cell lines was mediated mainly by DNAM-1 with only a minor role for other activating NK cell receptors. Furthermore, enterocytes isolated from duodenal biopsies expressed DNAM-1 ligands and were lysed by the RCD cell lines ex vivo. Although DNAM-1 on CD8(+) T cells and NK cells is known to mediate lysis of tumor cells, this study provides, to our knowledge, the first evidence that (pre)malignant cells themselves can acquire the ability to lyse epithelial cells via DNAM-1. This study confirms previous work on epithelial lysis by RCD cell lines and identifies a novel mechanism that potentially contributes to the gluten-independent tissue damage in RCD II and RCD-associated lymphoma.

  13. Identifying Genes Controlling Ferulate Cross-Linking Formation in Grass Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    de O. Buanafina, Marcia Maria [Pennsylvania State Univ., University Park, PA (United States)

    2013-10-16

    This proposal focuses on cell wall feruloylation and our long term goal is to identify and isolate novel genes controlling feruloylation and to characterize the phenotype of mutants in this pathway, with a spotlight on cell wall properties.

  14. Regulation of plant cells, cell walls and development by mechanical signals

    Energy Technology Data Exchange (ETDEWEB)

    Meyerowitz, Elliot M. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2016-06-14

    The overall goal of the revised scope of work for the final year of funding was to characterize cell wall biosynthesis in developing cotyledons and in the shoot apical meristem of Arabidopsis thaliana, as a way of learning about developmental control of cell wall biosynthesis in plants, and interactions between cell wall biosynthesis and the microtubule cytoskeleton. The proposed work had two parts – to look at the effect of mutation in the SPIRAL2 gene on microtubule organization and reorganization, and to thoroughly characterize the glycosyltransferase genes expressed in shoot apical meristems by RNA-seq experiments, by in situ hybridization of the RNAs expressed in the meristem, and by antibody staining of the products of the glycosyltransferases in meristems. Both parts were completed; the spiral2 mutant was found to speed microtubule reorientation after ablation of adjacent cells, supporting our hypothesis that reorganization correlates with microtubule severing, the rate of which is increased by the mutation. The glycosyltransferase characterization was completed and published as Yang et al. (2016). Among the new things learned was that primary cell wall biosynthesis is strongly controlled both by cell type, and by stage of cell cycle, implying not only that different, even adjacent, cells can have different sugar linkages in their (nonshared) walls, but also that a surprisingly large proportion of glycosyltransferases is regulated in the cell cycle, and therefore that the cell cycle regulates wall maturation to a degree previously unrecognized.

  15. Effect of Yeast Cell Morphology, Cell Wall Physical Structure and Chemical Composition on Patulin Adsorption.

    Science.gov (United States)

    Luo, Ying; Wang, Jianguo; Liu, Bin; Wang, Zhouli; Yuan, Yahong; Yue, Tianli

    2015-01-01

    The capability of yeast to adsorb patulin in fruit juice can aid in substantially reducing the patulin toxic effect on human health. This study aimed to investigate the capability of yeast cell morphology and cell wall internal structure and composition to adsorb patulin. To compare different yeast cell morphologies, cell wall internal structure and composition, scanning electron microscope, transmission electron microscope and ion chromatography were used. The results indicated that patulin adsorption capability of yeast was influenced by cell surface areas, volume, and cell wall thickness, as well as 1,3-β-glucan content. Among these factors, cell wall thickness and 1,3-β-glucan content serve significant functions. The investigation revealed that patulin adsorption capability was mainly affected by the three-dimensional network structure of the cell wall composed of 1,3-β-glucan. Finally, patulin adsorption in commercial kiwi fruit juice was investigated, and the results indicated that yeast cells could adsorb patulin from commercial kiwi fruit juice efficiently. This study can potentially simulate in vitro cell walls to enhance patulin adsorption capability and successfully apply to fruit juice industry.

  16. Frequent induction of chromosomal aberrations in in vivo skin fibroblasts after allogeneic stem cell transplantation: hints to chromosomal instability after irradiation

    International Nuclear Information System (INIS)

    Massenkeil, G.; Zschieschang, P.; Thiel, G.; Hemmati, P. G.; Budach, V.; Dörken, B.; Pross, J.; Arnold, R.

    2015-01-01

    Total body irradiation (TBI) has been part of standard conditioning regimens before allogeneic stem cell transplantation for many years. Its effect on normal tissue in these patients has not been studied extensively. We studied the in vivo cytogenetic effects of TBI and high-dose chemotherapy on skin fibroblasts from 35 allogeneic stem cell transplantation (SCT) patients. Biopsies were obtained prospectively (n = 18 patients) before, 3 and 12 months after allogeneic SCT and retrospectively (n = 17 patients) 23–65 months after SCT for G-banded chromosome analysis. Chromosomal aberrations were detected in 2/18 patients (11 %) before allogeneic SCT, in 12/13 patients (92 %) after 3 months, in all patients after 12 months and in all patients in the retrospective group after allogeneic SCT. The percentage of aberrant cells was significantly higher at all times after allogeneic SCT compared to baseline analysis. Reciprocal translocations were the most common aberrations, but all other types of stable, structural chromosomal aberrations were also observed. Clonal aberrations were observed, but only in three cases they were detected in independently cultured flasks. A tendency to non-random clustering throughout the genome was observed. The percentage of aberrant cells was not different between patients with and without secondary malignancies in this study group. High-dose chemotherapy and TBI leads to severe chromosomal damage in skin fibroblasts of patients after SCT. Our long-term data suggest that this damage increases with time, possibly due to in vivo radiation-induced chromosomal instability

  17. Cell wall proteins in seedling cotyledons of Prosopis chilensis.

    Science.gov (United States)

    Rodríguez, J G; Cardemil, L

    1994-01-01

    Four cell wall proteins of cotyledons of Prosopis chilensis seedlings were characterized by PAGE and Western analyses using a polyclonal antibody, generated against soybean seed coat extensin. These proteins had M(r)s of 180,000, 126,000, 107,000 and 63,000, as determined by SDS-PAGE. The proteins exhibited a fluorescent positive reaction with dansylhydrazine suggesting that they are glycoproteins; they did not show peroxidase activity. The cell wall proteins were also characterized by their amino acid composition and by their amino-terminal sequence. These analyses revealed that there are two groups of related cell wall proteins in the cotyledons. The first group comprises the proteins of M(r)s 180,000, 126,000, 107,000 which are rich in glutamic acid/glutamine and aspartic acid/asparagine and they have almost identical NH2-terminal sequences. The second group comprises the M(r) 63,000 protein which is rich in proline, glycine, valine and tyrosine, with an NH2-terminal sequence which was very similar to that of soybean proline-rich proteins.

  18. Hypergravity Effects on Dendritic Cells and Vascular Wall Interactions

    Science.gov (United States)

    Bellik, L.; Parenti, A.; Ledda, F.; Basile, V.; Romano, G.; Fusi, F.; Monici, M.

    2009-01-01

    Dendritic cells (DCs), the most potent antigen-presenting cells inducing specific immune responses, are involved in the pathogenesis of atherosclerosis. In this inflammatory disease, DCs increase in number, being particularly abundant in the shoulder regions of plaques. Since the exposure to altered gravitational conditions results in a significant impairment of the immune function, the aim of this study was to investigate the effects of hypergravity on both the function of DCs and their interactions with the vascular wall cells. Monocytes from peripheral blood mononuclear cells of healthy volunteers were sorted by CD14+ magnetic beads selection, cultured for 6 days in medium supplemented with GM-CSF and IL-4, followed by a further maturation stimulus. DC phenotype, assessed by flow cytometry, showed a high expression of the specific DC markers CD80, CD86, HLA-DR and CD83. The DCs obtained were then exposed to hypergravitational stimuli and their phenotype, cytoskeleton, ability to activate lymphocytes and interaction with vascular wall cells were investigated. The findings showed that the exposure to hypergravity conditions resulted in a significant impairment of DC cytoskeletal organization, without affecting the expression of DC markers. Moreover, an increase in DC adhesion to human vascular smooth muscle cells and in their ability to activate lymphocytes was observed.

  19. Cell wall composition and candidate biosynthesis gene expression during rice development

    DEFF Research Database (Denmark)

    Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra

    2016-01-01

    , we measured 15 cell wall chemical components, enzymatic digestibility and 18 cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had...... strong hypotheses for genes that synthesize xylans, mixed linkage glucan and pectin components. This work provides an extensive analysis of cell wall composition throughout rice development, identifies genes likely to synthesize grass cell walls, and provides a framework for development of genetically...

  20. Body-weight and chromosome aberrations induced by X-rays in somatic cells of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Marco, A. de; Belloni, M.P.

    1976-01-01

    Body-weight has been shown to influence the final expression of genetic damage by X-rays in Drosophila melanogaster. If larvae of Drosophila were raised up to the third instar in media containing different amounts of the same nutrient and in different conditions of crowding a positive correlation was observed between body-weight and frequency of chromosome aberrations induced by a given dose of X-rays in the somatic cells of their nerve ganglia. This effect, present in both sexes, is most plausibly attributed to a different capacity of big and small larvae for repairing radiation damage. (orig.) [de

  1. Al-induced root cell wall chemical components differences of wheat ...

    African Journals Online (AJOL)

    Jane

    2011-07-13

    Jul 13, 2011 ... Cell wall chemical contents of lignin, H2O2 and callose increased and contents of cellulose decreased. Changes of enzyme activities and cell wall chemical components were significant in both lines, but were more prominent in the ES8 line. The analysis indicated that under Al stress, differences in cell wall ...

  2. Raman imaging of lignin and cellulose distribution in black spruce wood (Picea mariana) cell walls

    Science.gov (United States)

    Umesh P. Agarwal

    2005-01-01

    A detailed understanding of wood cell wall structure and organization is important from both fundamental and practical point of views. A state-of- the-art 633-nm laser based confocal Raman microscope was used in situ to investigate the cell wall organization of black spruce wood. Chemical information on lignin and cellulose from morphologically distinct cell wall...

  3. Cell Wall Composition and Candidate Biosynthesis Gene Expression During Rice Development

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra; Peck, Matthew L.; Vega-Sánchez, Miguel E.; Williams, Brian; Chiniquy, Dawn M.; Saha, Prasenjit; Pattathil, Sivakumar; Conlin, Brian; Zhu, Lan; Hahn, Michael G.; Willats, William G. T.; Scheller, Henrik V.; Ronald, Pamela C.; Bartley, Laura E.

    2016-08-01

    Cell walls of grasses, including cereal crops and biofuel grasses, comprise the majority of plant biomass and intimately influence plant growth, development and physiology. However, the functions of many cell wall synthesis genes, and the relationships among and the functions of cell wall components remain obscure. To better understand the patterns of cell wall accumulation and identify genes that act in grass cell wall biosynthesis, we characterized 30 samples from aerial organs of rice (Oryza sativa cv. Kitaake) at 10 developmental time points, 3-100 d post-germination. Within these samples, we measured 15 cell wall chemical components, enzymatic digestibility and 18 cell wall polysaccharide epitopes/ligands. We also used quantitative reverse transcription-PCR to measure expression of 50 glycosyltransferases, 15 acyltransferases and eight phenylpropanoid genes, many of which had previously been identified as being highly expressed in rice. Most cell wall components vary significantly during development, and correlations among them support current understanding of cell walls. We identified 92 significant correlations between cell wall components and gene expression and establish nine strong hypotheses for genes that synthesize xylans, mixed linkage glucan and pectin components. This work provides an extensive analysis of cell wall composition throughout rice development, identifies genes likely to synthesize grass cell walls, and provides a framework for development of genetically improved grasses for use in lignocellulosic biofuel production and agriculture.

  4. Impact of accessibility and chemical composition on cell wall polysaccharide degradability of maize and lucerne stems

    NARCIS (Netherlands)

    Jung, H.G.; Jorgensen, M.A.; Linn, J.G.; Engels, F.M.

    2000-01-01

    Although lignification of forages is generally accepted as limiting cell wall degradability, prediction of degradation from cell wall composition is often difficult when forages are of similar maturity. It has been proposed that rumen microbe accessibility to potentially degradable cell walls is

  5. Stress analysis for wall structure in mobile hot cell design

    Energy Technology Data Exchange (ETDEWEB)

    Bahrin, Muhammad Hannan, E-mail: hannan@nuclearmalaysia.gov.my; Rahman, Anwar Abdul, E-mail: anwar@nuclearmalaysia.gov.my; Hamzah, Mohd Arif, E-mail: arif@nuclearmalaysia.gov.my; Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni [Prototype and Plant Development Centre, Technical Services Division, Malaysian Nuclear Agency (Malaysia)

    2016-01-22

    Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.

  6. Rapid detection of radiation-induced chromosomal aberrations in lymphocytes and hematopoietic progenitor cells by mFISH

    Energy Technology Data Exchange (ETDEWEB)

    Greulich, K.M.; Rhein, A.P.; Brueckner, M.; Molls, M. [Department of Radiation Oncology, Technical University of Munich, Ismaninger Strasse 22, D-81675 Munich (Germany); Kreja, L. [Institute for Occupational, Social and Environmental Medicine, University of Ulm, Ulm (Germany); Heinze, B. [Department of Medical Genetics, University of Ulm, Ulm (Germany); Weier, H.-U.G. [Life Sciences Division, E.O. Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Fuchs, P. [Vysis GmbH, Bergisch-Gladbach (Germany)

    2000-07-20

    Structural chromosome aberrations (SCAs) are sensitive indicators of a preceding exposure of the hematopoietic system to ionizing radiation. Cytogenetic investigations have therefore become routine tools for an assessment of absorbed radiation doses and their biological effects after occupational exposure or radiation accidents. Due to its speed and ease of use, fluorescence in situ hybridization (FISH) with whole chromosome painting (WCP) probes has become a method of choice to visualize SCAs. Until recently, this technique was limited to a rather small number of chromosomes, which could be tested simultaneously. As a result, only a fraction of the structural aberrations present in a sample could be detected and the overall dose effect had to be calculated by extrapolation. The recent introduction of two genome-wide screening techniques in tumor research, i.e., Spectral Karyotyping (SKY) and multicolor FISH (mFISH) now allows the detection of translocations involving any two non-homologous chromosomes. The present study was prompted by our desire to bring the power of mFISH to bear for the rapid identification of radiation-induced SCAs. We chose two model systems to investigate the utility of mFISH: lymphocytes that were exposed in vitro to 3 Gy photons and single hematopoietic progenitor cell colonies isolated from a Chernobyl victim 9 years after in vivo exposure to 5.4 Sv. In lymphocytes, we found up to 15 different chromosomes involved in rearrangements indicating complex radiation effects. Stable aberrations detected in hematopoietic cell colonies, on the other hand, showed involvement of up to three different chromosomes. These results demonstrated that mFISH is a rapid and powerful approach to detect and characterize radiation-induced SCAs in the hemopoietic system. The application of mFISH is expected to result in a more detailed and, thus, more informative picture of radiation effects. Eventually, this technique will allow researchers to rapidly delineate

  7. In situ analysis of cell wall polymers associated with phloem fibre cells in stems of hemp, Cannabis sativa L.

    Science.gov (United States)

    Blake, Anthony W; Marcus, Susan E; Copeland, James E; Blackburn, Richard S; Knox, J Paul

    2008-06-01

    A study of stem anatomy and the sclerenchyma fibre cells associated with the phloem tissues of hemp (Cannabis sativa L.) plants is of interest for both understanding the formation of secondary cell walls and for the enhancement of fibre utility as industrial fibres and textiles. Using a range of molecular probes for cell wall polysaccharides we have surveyed the presence of cell wall components in stems of hemp in conjunction with an anatomical survey of stem and phloem fibre development. The only polysaccharide detected to occur abundantly throughout the secondary cell walls of phloem fibres was cellulose. Pectic homogalacturonan epitopes were detected in the primary cell walls/intercellular matrices between the phloem fibres although these epitopes were present at a lower level than in the surrounding parenchyma cell walls. Arabinogalactan-protein glycan epitopes displayed a diversity of occurrence in relation to fibre development and the JIM14 epitope was specific to fibre cells, binding to the inner surface of secondary cell walls, throughout development. Xylan epitopes were found to be present in the fibre cells (and xylem secondary cell walls) and absent from adjacent parenchyma cell walls. Analysis of xylan occurrence in the phloem fibre cells of hemp and flax indicated that xylan epitopes were restricted to the primary cell walls of fibre cells and were not present in the secondary cell walls of these cells.

  8. Brahmarasayana protects against Ethyl methanesulfonate or Methyl methanesulfonate induced chromosomal aberrations in mouse bone marrow cells

    Directory of Open Access Journals (Sweden)

    Guruprasad Kanive

    2012-08-01

    Full Text Available Abstract Background Ayurveda, the traditional Indian system of medicine has given great emphasis to the promotion of health. Rasayana is one of the eight branches of Ayurveda which refers to rejuvenant therapy. It has been reported that rasayanas have immuno-modulatory, antioxidant and antitumor functions, however, the genotoxic potential and modulation of DNA repair of many rasayanas have not been evaluated. Methods The present study assessed the role of Brahmarasayana (BR on Ethyl methanesulfonate (EMS-and Methyl methanesulfonate (MMS-induced genotoxicity and DNA repair in in vivo mouse test system. The mice were orally fed with BR (5 g or 8 mg / day for two months and 24 h later EMS or MMS was given intraperitoneally. The genotoxicity was analyzed by chromosomal aberrations, sperm count, and sperm abnormalities. Results The results have revealed that BR did not induce significant chromosomal aberrations when compared to that of the control animals (p >0.05. On the other hand, the frequencies of chromosomal aberrations induced by EMS (240 mg / kg body weight or MMS (125 mg / kg body weight were significantly higher (p Conclusion The effect of BR, as it relates to antioxidant activity was not evident in liver tissue however rasayana treatment was observed to increase constitutive DNA base excision repair and reduce clastogenicity. Whilst, the molecular mechanisms of such repair need further exploration, this is the first report to demonstrate these effects and provides further evidence for the role of brahmarasayana in the possible improvement of quality of life.

  9. Clear Cell Adenocarcinoma Arising from Abdominal Wall Endometriosis

    Directory of Open Access Journals (Sweden)

    Thouraya Achach

    2008-01-01

    Full Text Available Endometriosis is a frequent benign disorder. Malignancy arising in extraovarian endometriosis is a rare event. A 49-year-old woman is presented with a large painful abdominal wall mass. She underwent a myomectomy, 20 years before, for uterus leiomyoma. Computed tomography suggested that this was a desmoid tumor and she underwent surgery. Histological examination showed a clear cell adenocarcinoma associated with endometriosis foci. Pelvic ultrasound, computed tomography, and endometrial curettage did not show any malignancy or endometriosis in the uterus and ovaries. Adjuvant chemotherapy was recommended, but the patient was lost to follow up. Six months later, she returned with a recurrence of the abdominal wall mass. She was given chemotherapy and then she was reoperated.

  10. Impact of processing on the noncovalent interactions between procyanidin and apple cell wall.

    Science.gov (United States)

    Le Bourvellec, Carine; Watrelot, Aude A; Ginies, Christian; Imberty, Anne; Renard, Catherine M G C

    2012-09-19

    Procyanidins can bind cell wall material in raw product, and it could be supposed that the same mechanism of retention of procyanidins by apple cell walls takes place in cooked products. To evaluate the influence of cell wall composition and disassembly during cooking on the cell walls' capacity to interact with procyanidins, four cell wall materials differing in their protein contents and physical characteristics were prepared: cell wall with proteins, cell wall devoid of protein, and two processed cell walls differing by their drying method. Protein contents varied from 23 to 99 mg/g and surface areas from 1.26 to 3.16 m(2)/g. Apple procyanidins with an average polymerization degree of 8.7 were used. The adsorption of apple procyanidins on solid cell wall material was quantified using the Langmuir isotherm formulation. The protein contents in cell wall material had no effect on procyanidin/cell wall interactions, whereas modification of the cell wall material by boiling, which reduces pectin content, and drying decreased the apparent affinity and increased the apparent saturation levels when constants were expressed relative to cell wall weight. However, boiling and drying increased apparent saturation levels and had no effect on apparent affinity when the same data were expressed per surface units. Isothermal titration calorimetry indicated strong affinity (K(a) = 1.4 × 10(4) M(-1)) between pectins solubilized by boiling and procyanidins. This study higllights the impact of highly methylated pectins and drying, that is, composition and structure of cell wall in the cell wall/procyanidin interactions.

  11. Seed coat mucilage cells of Arabidopsis thaliana as a model for plant cell wall research.

    Science.gov (United States)

    Arsovski, Andrej A; Haughn, George W; Western, Tamara L

    2010-07-01

    Plant cells are encased within a complex polysaccharide wall that strengthens the cell and has key roles in all aspects of plant cell growth, differentiation, and interaction with the environment. This dynamic structure is under continual modification during plant development, and its synthesis and modification require the activity of a myriad of enzymes. The mucilage secretory cells (MSCs) of the Arabidopsis thaliana seed coat provide a model for the discovery of novel genes involved in the synthesis, secretion and modification of cell wall components, particularly pectin. These cells synthesize copious amounts of pectinaceous mucilage during development and, upon hydration of the desiccated seed, the mucilage rapidly swells, bursts from the MSCs and surrounds the seed in a gelatinous capsule. Several genes affecting MSC differentiation, pectin synthesis, and mucilage release have been identified and additional genes involved in these and related processes including pectin secretion and the mechanical alteration of cell walls await to be discovered.

  12. Investigation of the functional role of CSLD proteins in plant cell wall deposition

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Erik Etlar [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-11-21

    The overall goal of this research proposal was to characterize the molecular machinery responsible for polarized secretion of cell wall components in Arabidopsis thaliana. We have used the polarized expansion that occurs during root hair cell growth to identify membrane trafficking pathways involved in polarized secretion of cell wall components to the expanding tips of these cells, and we have recently shown that CSLD3 is preferentially targeted to the apical plasma membranes in root hair cells, where it plays essential roles during cell wall deposition in these cells. The specific aims of the project are designed to answer the following objective: Identification of the cell wall polysaccharide class that CSLD proteins synthesize.

  13. Measuring the Mechanical Properties of Plant Cell Walls

    Directory of Open Access Journals (Sweden)

    Hannes Vogler

    2015-03-01

    Full Text Available The size, shape and stability of a plant depend on the flexibility and integrity of its cell walls, which, at the same time, need to allow cell expansion for growth, while maintaining mechanical stability. Biomechanical studies largely vanished from the focus of plant science with the rapid progress of genetics and molecular biology since the mid-twentieth century. However, the development of more sensitive measurement tools renewed the interest in plant biomechanics in recent years, not only to understand the fundamental concepts of growth and morphogenesis, but also with regard to economically important areas in agriculture, forestry and the paper industry. Recent advances have clearly demonstrated that mechanical forces play a crucial role in cell and organ morphogenesis, which ultimately define plant morphology. In this article, we will briefly review the available methods to determine the mechanical properties of cell walls, such as atomic force microscopy (AFM and microindentation assays, and discuss their advantages and disadvantages. But we will focus on a novel methodological approach, called cellular force microscopy (CFM, and its automated successor, real-time CFM (RT-CFM.

  14. [Hydroxyproline: Rich glycoproteins of the plant and cell wall

    Energy Technology Data Exchange (ETDEWEB)

    Varner, J.E.

    1993-01-01

    Since xylem tissue includes the main cell types which are lignified, we are interested in gene expression of glycine-rich proteins and proline-rich proteins, and other proteins which are involved in secondary cell wall thickening during xylogenesis. Since the main feature of xylogenesis is the deposition of additional wall components, study of the mechanism of xylogenesis will greatly advance our knowledge of the synthesis and assembly of wall macromolecules. We are using the in vitro xylogenesis system from isolated Zinnia mesophyll cells to isolate genes which are specifically expressed during xylogenesis. We have used subtractive hybridization methods to isolate a number of cDNA clones for differentially regulated genes from the cells after hormonal induction. So far, we have partially characterized 18 different cDNA clones from 239 positive clones. These differentially regulated genes can be divided into three sets according to the characteristics of gene expression in the induction medium and the control medium. The first set is induced in both the induction medium and the control medium without hormones. The second set is induced mainly in the induction medium and in the control medium with the addition of NAA alone. Two of thesegenes are exclusively induced by auxin. The third set of genes is induced mainly in the induction medium. Since these genes are not induced by either auxin or cytokinin alone, they may be directly involved in the process of xylogenesis. Our experiments on the localization of H[sub 2]O[sub 2] production reinforce the earlier ideas of others that H[sub 2]O[sub 2] is involved in normal lignification.

  15. Relationship between chromosomal aberration of bone marrow cells and dosage of irradiation after 46Sc internal pollution and external low dose X-irradiation in mice

    International Nuclear Information System (INIS)

    Li Guofu; Li Zhang; Wu Yin

    1989-01-01

    The relationship between chromosomal aberration of bone marrow cells and dosage in mice 24 h after 46 Sc internal pollution combined with external low dose whole body X-irradiation was quantiatively studied. The results showed that the relationship between chromosomal aberration and dosage was expressed in a linear regression equation. The chromosomal aberration rate was lower in the combined exposure than that of the sum of internal and external exposures, but higher than that of either the internal or external exposure singly. The relationship between chromosomal aberration and time was expressed in the following three phase exponential function: Y(t) = 2.9078 exp 0.27668t + 2.9371 exp -0.0778t + 2.3786 -0.01788t . By means of fit test, there was no significant difference between the determined and the theoretical values. The 90% theoretical values got from all the equations distributed over the determined values

  16. TGF-{beta}-stimulated aberrant expression of class III {beta}-tubulin via the ERK signaling pathway in cultured retinal pigment epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eun Jee [Department of Ophthalmology, National Health Insurance Corporation Ilsan Hospital, Gyeonggi-do (Korea, Republic of); Chun, Ji Na; Jung, Sun-Ah [Konyang University Myunggok Medical Research Institute, Kim' s Eye Hospital, Konyang University College of Medicine, Seoul (Korea, Republic of); Cho, Jin Won [Department of Biology, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Lee, Joon H., E-mail: joonhlee@konyang.ac.kr [Konyang University Myunggok Medical Research Institute, Kim' s Eye Hospital, Konyang University College of Medicine, Seoul (Korea, Republic of)

    2011-11-18

    Highlights: Black-Right-Pointing-Pointer TGF-{beta} induces aberrant expression of {beta}III in RPE cells via the ERK pathway. Black-Right-Pointing-Pointer TGF-{beta} increases O-GlcNAc modification of {beta}III in RPE cells. Black-Right-Pointing-Pointer Mature RPE cells have the capacity to express a neuron-associated gene by TGF-{beta}. -- Abstract: The class III {beta}-tubulin isotype ({beta}{sub III}) is expressed exclusively by neurons within the normal human retina and is not present in normal retinal pigment epithelial (RPE) cells in situ or in the early phase of primary cultures. However, aberrant expression of class III {beta}-tubulin has been observed in passaged RPE cells and RPE cells with dedifferentiated morphology in pathologic epiretinal membranes from idiopathic macular pucker, proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR). Transforming growth factor-{beta} (TGF-{beta}) has been implicated in dedifferentiation of RPE cells and has a critical role in the development of proliferative vitreoretinal diseases. Here, we investigated the potential effects of TGF-{beta} on the aberrant expression of class III {beta}-tubulin and the intracellular signaling pathway mediating these changes. TGF-{beta}-induced aberrant expression and O-linked-{beta}-N-acetylglucosamine (O-GlcNac) modification of class III {beta}-tubulin in cultured RPE cells as determined using Western blotting, RT-PCR and immunocytochemistry. TGF-{beta} also stimulated phosphorylation of ERK. TGF-{beta}-induced aberrant expression of class III {beta}-tubulin was significantly reduced by pretreatment with U0126, an inhibitor of ERK phosphorylation. Our findings indicate that TGF-{beta} stimulated aberrant expression of class III {beta}-tubulin via activation of the ERK signaling pathway. These data demonstrate that mature RPE cells have the capacity to express a neuron-associated gene in response to TGF-{beta} stimulation and provide useful information

  17. Immunocytochemical characterization of the cell walls of bean cell suspensions during habituation and dehabituation to dichlobenil

    DEFF Research Database (Denmark)

    Garcia-Angulo, P.; Willats, W. G. T.; Encina, A. E.

    2006-01-01

    showed an overall composition similar to that of non-habituated cells, with exception of an increase in glucose in hemicellulosic fractions tightly bound to cellulose. However, these cells also showed reduced levels of extensin and AGP labelling. These differences could be related to the high tolerance......The effects of the cellulose inhibitor dichlobenil on the cell wall composition and structure during the habituation/dehabituation process of suspension-cultured bean cells were assessed. A range of techniques were used including cell wall fractionation, sugar analysis, immunofluorescence...

  18. Immunotherapy with BCG cell wall plus irradiated tumor cells

    Energy Technology Data Exchange (ETDEWEB)

    Mizukuro, Tomoyuki (Kyoto Prefectural Univ. of Medicine (Japan))

    1983-04-01

    Two different fibrosarcomas (MCB-I, MCB-II) were induced by methylcholcholanthrene in syngeneic Balb/C mice were used. The tumor cells irradiated with 5,000 to 30,000 rads did not growth in mice on 30 days after inoculation. The viable tumor cells were challenged intradermally to mice on 7 days after inoculation of the tumor cells irradiated with 5,000 to 30,000 rads. The challenged tumor cells were all rejected at 30 days after inoculation. Mice were challenged with 5 x 10/sup 5/ viable tumor cells on 7 days after inoculation of 10/sup 3/ to 10/sup 8/ irradiated tumor cells. Mice pretreated with 10/sup 5/ or 10/sup 6/ irradiated tumor cells rejected the tumor cells completely. The viable tumor cells were challenged to mice on 7 days after inoculation of BCG-CW emulsion plus 10/sup 6/ irradiated tumor cells. 0, 50, 100, 200, and 400 mu g of BCG-CW emulsion were mixed in 10/sup 6/ irradiated tumor cells. Optimal dosage of BCG-CW emulsion was 50 or 100 mu g. BCG-CW emulsion plus irradiated tumor cells were injected subcutaneously to the mice after tumor cells inoculation. Three injections of the vaccine significantly suppressed the tumor outgrowth, but not one or two injections in no-treated mice. However, in the mice pretreated with BCG-CW emulsion, the tumor growth was significantly suppressed by one or two injections of the vaccine. Especially, the three injections of the vaccine significantly suppressed the tumor growth and the 25% of the mice were completely cured. The effect of the vaccine was almost the same grade by contralateral or ipsilateral treatment. The irradiated MCB-II tumor cells plus BCG-CW emulsion were not effective to the MCB-1 tumor bearing mice, suggesting the anti-tumor effect of this vaccine was immunologically specific.

  19. Architecture-based multiscale computational modeling of plant cell wall mechanics to examine the hydrogen-bonding hypothesis of the cell wall network structure model.

    Science.gov (United States)

    Yi, Hojae; Puri, Virendra M

    2012-11-01

    A primary plant cell wall network was computationally modeled using the finite element approach to study the hypothesis of hemicellulose (HC) tethering with the cellulose microfibrils (CMFs) as one of the major load-bearing mechanisms of the growing cell wall. A computational primary cell wall network fragment (10 × 10 μm) comprising typical compositions and properties of CMFs and HC was modeled with well-aligned CMFs. The tethering of HC to CMFs is modeled in accordance with the strength of the hydrogen bonding by implementing a specific load-bearing connection (i.e. the joint element). The introduction of the CMF-HC interaction to the computational cell wall network model is a key to the quantitative examination of the mechanical consequences of cell wall structure models, including the tethering HC model. When the cell wall network models with and without joint elements were compared, the hydrogen bond exhibited a significant contribution to the overall stiffness of the cell wall network fragment. When the cell wall network model was stretched 1% in the transverse direction, the tethering of CMF-HC via hydrogen bonds was not strong enough to maintain its integrity. When the cell wall network model was stretched 1% in the longitudinal direction, the tethering provided comparable strength to maintain its integrity. This substantial anisotropy suggests that the HC tethering with hydrogen bonds alone does not manifest sufficient energy to maintain the integrity of the cell wall during its growth (i.e. other mechanisms are present to ensure the cell wall shape).

  20. Proteomic analysis of cell walls of two developmental stages of alfalfa stems.

    Science.gov (United States)

    Verdonk, Julian C; Hatfield, Ronald D; Sullivan, Michael L

    2012-01-01

    Cell walls are important for the growth and development of all plants. They are also valuable resources for feed and fiber, and more recently as a potential feedstock for bioenergy production. Cell wall proteins comprise only a fraction of the cell wall, but play important roles in establishing the walls and in the chemical interactions (e.g., crosslinking) of cell wall components. This crosslinking provides structure, but restricts digestibility of cell wall complex carbohydrates, limiting available energy in animal and bioenergy production systems. Manipulation of cell wall proteins could be a strategy to improve digestibility. An analysis of the cell wall proteome of apical alfalfa stems (less mature, more digestible) and basal alfalfa stems (more mature, less digestible) was conducted using a recently developed low-salt/density gradient method for the isolation of cell walls. Walls were subsequently subjected to a modified extraction utilizing EGTA to remove pectins, followed by a LiCl extraction to isolate more tightly bound proteins. Recovered proteins were identified using shotgun proteomics. We identified 272 proteins in the alfalfa stem cell wall proteome, 153 of which had not previously been identified in cell wall proteomic analyses. Nearly 70% of the identified proteins were predicted to be secreted, as would be expected for most cell wall proteins, an improvement over previously published studies using traditional cell wall isolation methods. A comparison of our and several other cell wall proteomic studies indicates little overlap in identified proteins among them, which may be largely due to differences in the tissues used as well as differences in experimental approach.

  1. Proteomic analysis of cell walls of two developmental stages of alfalfa stems

    Directory of Open Access Journals (Sweden)

    Julian C Verdonk

    2012-12-01

    Full Text Available Cell walls are important for the growth and development of all plants. They are also valuable resources for feed and fiber, and more recently as a potential feedstock for bioenergy production. Cell wall proteins comprise only a fraction of the cell wall, but play important roles in establishing the walls and in the chemical interactions (e.g. crosslinking of cell wall components. This crosslinking provides structure, but restricts digestibility of cell wall complex carbohydrates, limiting available energy in animal and bioenergy production systems. Manipulation of cell wall proteins could be a strategy to improve digestibility. An analysis of the cell wall proteome of apical alfalfa stems (less mature, more digestible and basal alfalfa stems (more mature, less digestible was conducted using a recently developed low-salt/density gradient method for the isolation of cell walls. Walls were subsequently subjected to a modified extraction utilizing EGTA to remove pectins, followed by a LiCl extraction to isolate more tightly bound proteins. Recovered proteins were identified using shotgun proteomics. We identified 272 proteins in the alfalfa stem cell wall proteome, 153 of which had not previously been identified in cell wall proteomic analyses. Nearly 70% percent of the identified proteins were predicted to be secreted, as would be expected for most cell wall proteins, an improvement over previously published studies using traditional cell wall isolation methods. A comparison of our and several other cell wall proteomic studies indicates little overlap in identified proteins among them, which may be largely due to differences in the tissues used as well as differences in experimental approach.

  2. Populations of latent Mycobacterium tuberculosis lack a cell wall: Isolation, visualization, and whole-genome characterization

    Directory of Open Access Journals (Sweden)

    Ali Akbar Velayati

    2016-01-01

    Conclusion: Here, we show cell-wall free cells of MTB bacilli in their latent state, and the biological adaptation of these cells was more phenotypic in nature than genomic. These cell-wall free cells represent a good model for understanding the nature of TB latency.

  3. An improved in vitro model to characterize invasive growing cancer cells simultaneously by function and genetic aberrations.

    Science.gov (United States)

    Jung, V; Wullich, B; Kamradt, J; Stöckle, M; Unteregger, G

    2007-03-01

    Invasion into the surrounding tissue and bone metastasis is a common feature of advanced prostate cancer. Chromosomal and other genetic or epigenetic abnormalities were aligned to this behaviour mostly by using permanent cell lines, paraffin embedded tissue or primary tumour samples. Both attempts fail to reflect either the original situation or functional information in the patient's tissue. Thus, we developed an improved in vitro assay to follow invasion of prostate cancer cells derived from fresh samples of radical prostatectomy specimens. Fresh tumour samples were applied onto Matrigeltrade mark-coated invasion chambers using a cocultivation model. Invasive growing cells were harvested from the bottom of the membrane or from the underlying gel and further characterized using comparative genomic hybridization. Prostate cancer cells have the capability to invasively grow through the barrier of a Matrigeltrade mark and could easily be sampled in a pad of Matrigeltrade mark. Comparative genomic hybridization revealed characteristic chromosomal aberrations of the invasive growing cells. Noteworthy is their ability to spheroid formation, which allows for further cell propagation by standard cell culture methods. Thus, our improved invasion model is a tool for the sampling of invasive growing cancer cells from fresh human tumour material allowing for functional as well as genetic studies.

  4. Aberrant DNA methylation-induced gene inactivation is associated with the diagnosis and/or therapy of T-cell leukemias.

    Science.gov (United States)

    Kim, Sun Young; Shin, Dong-Yeop; Kim, Sang-Man; Lee, Minyoung; Kim, Eun Ju

    2016-08-01

    Aberrant hypermethylation of tumor suppressor genes is known to play an important role in the development of many tumors, and aberrant DNA hypermethylation was recently identified in hematologic malignancies, where it is thought to hold relevance in leukemogenesis. Here, we report that there are differences in the DNA methylation patterns seen in normal peripheral blood and two T-cell leukemia cell lines. We identify nine genes (CLEC4E, CR1, DBC1, EPO, HAL-DOA, IGF2, IL12B, ITGA1, and LMX1B) that are significantly hypermethylated in T-cell leukemias cell lines, and suggest that aberrant hypermethylation of these normally unmethylated genes may induce their transcriptional and expressional silencing. Furthermore, we observed that the expression levels of DNMT1 and DNMT3a were significantly decreased by 5-aza-2'-deoxycytidine (5-Aza-dC), which is a demethylation agent known to deplete DNA methyltransferases (DNMTs) in leukemia cancer cells and restore the expression levels of their target genes in Jurkat cells. This result suggests that the overexpression of DNMTs could contribute to the development of T-cell leukemias by inducing hypermethylation of the target genes. Together, our results show that aberrant hypermethylation is an important molecular mechanism in the progression of T-cell leukemias, and thus could prove useful as a prognostic and/or diagnostic marker. Moreover, 5-Aza-dC might be a promising candidate for the treatment of T-cell leukemia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Profiling the Hydrolysis of Isolated Grape Berry Skin Cell Walls by Purified Enzymes.

    Science.gov (United States)

    Zietsman, Anscha J J; Moore, John P; Fangel, Jonatan U; Willats, William G T; Vivier, Melané A

    2015-09-23

    The unraveling of crushed grapes by maceration enzymes during winemaking is difficult to study because of the complex and rather undefined nature of both the substrate and the enzyme preparations. In this study we simplified both the substrate, by using isolated grape skin cell walls, and the enzyme preparations, by using purified enzymes in buffered conditions, to carefully follow the impact of the individual and combined enzymes on the grape skin cell walls. By using cell wall profiling techniques we could monitor the compositional changes in the grape cell wall polymers due to enzyme activity. Extensive enzymatic hydrolysis, achieved with a preparation of pectinases or pectinases combined with cellulase or hemicellulase enzymes, completely removed or drastically reduced levels of pectin polymers, whereas less extensive hydrolysis only opened up the cell wall structure and allowed extraction of polymers from within the cell wall layers. Synergistic enzyme activity was detectable as well as indications of specific cell wall polymer associations.

  6. Cellulose-hemicellulose interaction in wood secondary cell-wall

    Science.gov (United States)

    Zhang, Ning; Li, Shi; Xiong, Liming; Hong, Yu; Chen, Youping

    2015-12-01

    The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose.

  7. Cellulose-hemicellulose interaction in wood secondary cell-wall

    International Nuclear Information System (INIS)

    Zhang, Ning; Li, Shi; Hong, Yu; Chen, Youping; Xiong, Liming

    2015-01-01

    The wood cell wall features a tough and relatively rigid fiber reinforced composite structure. It acts as a pressure vessel, offering protection against mechanical stress. Cellulose microfibrils, hemicellulose and amorphous lignin are the three major components of wood. The structure of secondary cell wall could be imagined as the same as reinforced concrete, in which cellulose microfibrils acts as reinforcing steel bar and hemicellulose-lignin matrices act as the concrete. Therefore, the interface between cellulose and hemicellulose/lignin plays a significant role in determine the mechanical behavior of wood secondary cell wall. To this end, we present a molecular dynamics (MD) simulation study attempting to quantify the strength of the interface between cellulose microfibrils and hemicellulose. Since hemicellulose binds with adjacent cellulose microfibrils in various patterns, the atomistic models of hemicellulose-cellulose composites with three typical binding modes, i.e. bridge, loop and random binding modes are constructed. The effect of the shape of hemicellulose chain on the strength of hemicellulose-cellulose composites under shear loadings is investigated. The contact area as well as hydrogen bonds between cellulose and hemicellulose, together with the covalent bonds in backbone of hemicellulose chain are found to be the controlling parameters which determine the strength of the interfaces in the composite system. For the bridge binding model, the effect of shear loading direction on the strength of the cellulose material is also studied. The obtained results suggest that the shear strength of wood-inspired engineering composites can be optimized through maximizing the formations of the contributing hydrogen bonds between cellulose and hemicellulose. (paper)

  8. Auxin-induced modifications of cell wall polysaccharides in cat coleoptile segments. Effect of galactose

    International Nuclear Information System (INIS)

    Yamamoto, R.; Masuda, Y.

    1984-01-01

    Galactose inhibits auxin-induced cell elongation in oat coleoptile segments. Cell elongation induced by exogenously applied auxin is controlled by factors such as auxin uptake, cell wall loosening, osmotic concentration of sap and hydraulic conductivity. However, galactose does not have any effect on these factors. The results discussed in this paper led to the conclusion that galactose does not affect cell wall loosening which controls rapid growth, but inhibits cell wall synthesis which is required to maintain long-term growth

  9. A radioimmunoassay for lignin in plant cell walls

    Energy Technology Data Exchange (ETDEWEB)

    Dawley, R.M.

    1989-01-01

    Lignin detection and determination in herbaceous tissue requires selective, specific assays which are not currently available. A radioimmunoassay (RIA) was developed to study lignin metabolism in these tissues. A {beta}-aryl ether lignin model compound was synthesized, linked to keyhole limpet hemocyanin using a water-soluble carbodiimide, and injected into rabbits. The highest titer of the antiserum obtained was 34 {eta}g/mL of model derivatized BSA. An in vitro system was developed to characterize the RIA. The model compound was linked to amino activated polyacrylamide beads to mimic lignin in the cell walls. {sup 125}I Radiolabelled protein A was used to detect IgG antibody binding. The RIA was shown in the in vitro system to exhibit saturable binding. The amount of antibody bound decreased when the serum was diluted. Immunoelectrophoresis and competitive binding experiments confirmed that both aromatic rings of the lignin model compound had been antigenic. Chlorogenic acid, a phenolic known to be present in plant cells, did not compete for antibody binding. The RIA was used to measure lignin in milled plant samples and barley seedlings. Antiserum binding to wheat cell walls and stressed barley segments was higher than preimmune serum binding. Antibody binding to stressed barley tissue decreased following NaClO{sub 2} delignification. The RIA was found to be less sensitive than expected, so several avenues for improving the method are discussed.

  10. Lignification in poplar tension wood lignified cell wall layers.

    Science.gov (United States)

    Yoshinaga, Arata; Kusumoto, Hiroshi; Laurans, Françoise; Pilate, Gilles; Takabe, Keiji

    2012-09-01

    The lignification process in poplar tension wood lignified cell wall layers, specifically the S(1) and S(2) layers and the compound middle lamella (CML), was analysed using ultraviolet (UV) and transmission electron microscopy (TEM). Variations in the thickness of the gelatinous layer (G-layer) were also measured to clarify whether the lignified cell wall layers had completed their lignification before the deposition of G-layers, or, on the contrary, if lignification of these layers was still active during G-layer formation. Observations using UV microscopy and TEM indicated that both UV absorbance and the degree of potassium permanganate staining increased in the CML and S(1) and S(2) layers during G-layer formation, suggesting that the lignification of these lignified layers is still in progress during G-layer formation. In the context of the cell-autonomous monolignol synthesis hypothesis, our observations suggest that monolignols must go through the developing G-layer during the lignification of CML and the S(1) and S(2) layers. The alternative hypothesis of external synthesis (in the rays) does not require that monolignols go through the G-layer before being deposited in the CML, or the S(1) and S(2) layers. Interestingly, the previous observation of lignin in the poplar G-layer was not confirmed with the microscopy techniques used in the present study.

  11. The Mechanisms of Plant Cell Wall Deconstruction during Enzymatic Hydrolysis

    DEFF Research Database (Denmark)

    Thygesen, Lisbeth Garbrecht; E. Thybring, Emil; Johansen, Katja Salomon

    2014-01-01

    Mechanical agitation during enzymatic hydrolysis of insoluble plant biomass at high dry matter contents is indispensable for the initial liquefaction step in biorefining. It is known that particle size reduction is an important part of liquefaction, but the mechanisms involved are poorly understood....... Here we put forward a simple model based on mechanical principles capable of capturing the result of the interaction between mechanical forces and cell wall weakening via hydrolysis of glucosidic bonds. This study illustrates that basic material science insights are relevant also within biochemistry...

  12. Mass spectrometry for characterizing plant cell wall polysaccharides

    Directory of Open Access Journals (Sweden)

    Stefan eBauer

    2012-03-01

    Full Text Available Mass spectrometry is a selective and powerful technique to obtain identification and structural information on compounds present in complex mixtures. Since it requires only small sample amount it is an excellent tool for researchers interested in detecting changes in composition of complex carbohydrates of plants. This mini-review gives an overview of common mass spectrometry techniques applied to the analysis of plant cell wall carbohydrates. It presents examples in which mass spectrometry has been used to elucidate the structure of oligosaccharides derived from hemicelluloses and pectins and illustrates how information on sequence, linkages, branching and modifications are obtained from characteristic fragmentation patterns.

  13. Saccharomyces cerevisiae cell wall products: The effects on gut ...

    African Journals Online (AJOL)

    It consisted of a negative control, 2 levels of Bio-Mos® (2 g/kg and 4 g/kg), 2 levels of MRF (0.1 g/kg and 0.2 g/kg) and 2 treatments combining the cell wall preparations (2 g/kg Bio-Mos® + 0.1 g/kg MRF and 4 g/kg Bio-Mos® + 0.2 g/kg MRF). Day-old male broiler chicks were randomly allocated to the seven treatments and ...

  14. Forage digestibility: the intersection of cell wall lignification and plant tissue anatomy

    Science.gov (United States)

    Cellulose and the other polysaccharides present in forage cell walls can be completely degraded by the rumen microflora but only when these polysaccharides have been isolated from the wall and all matrix structures eliminated. Understanding how cell wall component interactions limit microbial degrad...

  15. High-resolution solution-state NMR of unfractionated plant cell walls

    Science.gov (United States)

    John Ralph; Fachuang Lu; Hoon Kim; Dino Ress; Daniel J. Yelle; Kenneth E. Hammel; Sally A. Ralph; Bernadette Nanayakkara; Armin Wagner; Takuya Akiyama; Paul F. Schatz; Shawn D. Mansfield; Noritsugu Terashima; Wout Boerjan; Bjorn Sundberg; Mattias Hedenstrom

    2009-01-01

    Detailed structural studies on the plant cell wall have traditionally been difficult. NMR is one of the preeminent structural tools, but obtaining high-resolution solution-state spectra has typically required fractionation and isolation of components of interest. With recent methods for dissolution of, admittedly, finely divided plant cell wall material, the wall can...

  16. Modification of antioxidant systems in cell walls of maize roots by different nitrogen sources

    Energy Technology Data Exchange (ETDEWEB)

    Hadži-Tašković Šukalović V; Vuletić, M.; Marković, K.; Željko, Vučinić; Kravić, N.

    2016-07-01

    Antioxidant systems of maize root cell walls grown on different nitrogen sources were evaluated. Plants were grown on a medium containing only NO3- or the mixture of NO3-+NH4+, in a 2:1 ratio. Eleven-day old plants, two days after the initiation of lateral roots, were used for the experiments. Cell walls were isolated from lateral roots and primary root segments, 2-7 cm from tip to base, representing zones of intense or decreased growth rates, respectively. Protein content and the activity of enzymes peroxidase, malate dehydrogenase and ascorbate oxidase ionically or covalently bound to the walls, as well as cell wall phenolic content and antioxidant capacity, were determined. Cell walls of plants grown on mixed N possess more developed enzymatic antioxidant systems and lower non-enzymatic antioxidant defenses than cell walls grown on NO3-. Irrespective of N treatment, the activities of all studied enzymes and protein content were higher in cell walls of lateral compared to primary roots. Phenolic content of cell walls isolated from lateral roots was higher in NO3--grown than in mixed N grown plants. No significant differences could be observed in the isozyme patterns of cell wall peroxidases isolated from plants grown on different nutrient solution. Our results indicate that different N treatments modify the antioxidant systems of root cell walls. Treatment with NO3- resulted in an increase of constitutive phenolic content, while the combination of NO3-+NH4+ elevated the redox enzyme activities in root cell walls.

  17. A novel screening method for cell wall mutants in Aspergillus niger identifies UDP-galactopyranose mutase as an important protein in fungal cell wall biosynthesis

    NARCIS (Netherlands)

    Damveld, R.A.; Franken, A.; Arentshorst, M.; Punt, P.J.; Klis, F.M.; Hondel, C.A.M.J.J. van den; Ram, A.F.J.

    2008-01-01

    To identify cell wall biosynthetic genes in filamentous fungi and thus potential targets for the discovery of new antifungals, we developed a novel screening method for cell wall mutants. It is based on our earlier observation that the Aspergillus niger agsA gene, which encodes a putative a-glucan

  18. Spontaneous class switch recombination in B cell lymphopoiesis generates aberrant switch junctions and is increased after VDJ rearrangement.

    Science.gov (United States)

    Edry, Efrat; Koralov, Sergei B; Rajewsky, Klaus; Melamed, Doron

    2007-11-15

    Mature B cells replace the mu constant region of the H chain with a downstream isotype in a process of class switch recombination (CSR). Studies suggest that CSR induction is limited to activated mature B cells in the periphery. Recently, we have shown that CSR spontaneously occur in B lymphopoiesis. However, the mechanism and regulation of it have not been defined. In this study, we show that spontaneous CSR occurs at all stages of B cell development and generates aberrant joining of the switch junctions as revealed by: 1) increased load of somatic mutations around the CSR break points, 2) reduced sequence overlaps at the junctions, and 3) excessive switch region deletion. In addition, we found that incidence of spontaneous CSR is increased in cells carrying VDJ rearrangements. Our results reveal major differences between spontaneous CSR in developing B cells and CSR induced in mature B cells upon activation. These differences can be explained by deregulated expression or function of activation-induced cytidine deaminase early in B cell development.

  19. Benzene-Induced Aberrant miRNA Expression Profile in Hematopoietic Progenitor Cells in C57BL/6 Mice.

    Science.gov (United States)

    Wei, Haiyan; Zhang, Juan; Tan, Kehong; Sun, Rongli; Yin, Lihong; Pu, Yuepu

    2015-11-12

    Benzene is a common environmental pollutant that causes hematological alterations. MicroRNAs (miRNAs) may play a role in benzene-induced hematotoxicity. In this study, C57BL/6 mice showed significant hematotoxicity after exposure to 150 mg/kg benzene for 4 weeks. Benzene exposure decreased not only the number of cells in peripheral blood but also hematopoietic progenitor cells in the bone marrow. Meanwhile, RNA from Lin(-) cells sorted from the bone marrow was applied to aberrant miRNA expression profile using Illumina sequencing. We found that 5 miRNAs were overexpressed and 45 miRNAs were downregulated in the benzene exposure group. Sequencing results were confirmed through qRT-PCR. Furthermore, we also identified five miRNAs which significantly altered in Lin(-)c-Kit⁺ cells obtained from benzene-exposed mice, including mmu-miR-34a-5p; mmu-miR-342-3p; mmu-miR-100-5p; mmu-miR-181a-5p; and mmu-miR-196b-5p. In summary, we successfully established a classical animal model to induce significant hematotoxicity by benzene injection. Benzene exposure may cause severe hematotoxicity not only to blood cells in peripheral circulation but also to hematopoietic cells in bone marrow. Benzene exposure also alters miRNA expression in hematopoietic progenitor cells. This study suggests that benzene induces alteration in hematopoiesis and hematopoiesis-associated miRNAs.

  20. Aberrant Expression of MHC Class II in Melanoma Attracts Inflammatory Tumor-Specific CD4+ T- Cells, Which Dampen CD8+ T-cell Antitumor Reactivity

    DEFF Research Database (Denmark)

    Donia, Marco; Andersen, Rikke; Kjeldsen, Julie W

    2015-01-01

    populations and correspondingly expanded autologous tumor-infiltrating lymphocytes (TIL), we show how MHC class II expression on melanoma cells associates with strong MHC class II-restricted CD4(+) T-cell responses that are specific for tumors. Notably, we found that tumor-specific CD4(+) T-cell responses...... were dominated by TNF production. TNF reduced CD8(+) T-cell activation in IFNγ-rich environments resembling a tumor site. Conversely, direct CD4(+) T-cell responses had no influence on either the proliferation or viability of melanoma cells. Taken together, our results illustrate a novel immune escape...... mechanism that can be activated by aberrant expression of MHC class II molecules, which by attracting tumor-specific CD4(+) T cells elicit a local inflammatory response dominated by TNF that, in turn, inhibits cytotoxic CD8(+) T-cell responses...

  1. The effect of defective DNA double-strand break repair on mutations and chromosome aberrations in the Chinese hamster cell mutant XR-V15B

    International Nuclear Information System (INIS)

    Helbig, R.; Speit, G.; Zdzienicka, M.Z.

    1995-01-01

    The radiosensitive Chinese hamster cell line XR-V15B was used to study the effect of decreased rejoining of DNA double-strand breaks (DSBs) on gene mutations and chromosome aberrations. XR-V15B cells are hypersensitive to the cytotoxic effects of neocarzinostatin (NCS) and methyl methanesulfonate (MMS). Both mutagens induced more chromosome aberrations in XR-V15B cells than in the parental cell strain. The clastogenic action of NCS was characterized by the induction of predominantly chromosome-type aberrations in cells of both strains, whereas MMS induced mainly chromatid aberrations. The frequency of induced gene mutations at the hprt locus was not increased compared to the parental V79 cells when considering the same survival level. Molecular analysis by multiplex polymerase chain reaction (PCR) of mutants induced by NCS revealed a high frequency of deletions in cells of both cell lines. Methyl methane-sulfonate induced mainly mutations without visible change in the PCR pattern, which probably represent point mutations. Our findings suggest a link between a defect in DNA DSB repair and increased cytotoxic and clastogenic effects. However, a decreased ability to rejoin DNA DSBs does not seem to influence the incidence and types of gene mutations at the hprt locus induced by NCS and MMS. 28 refs., 4 figs., 3 tabs

  2. Cellulose synthesis inhibition, cell expansion, and patterns of cell wall deposition in Nitella internodes

    International Nuclear Information System (INIS)

    Richmond, P.A.; Metraux, J.P.

    1984-01-01

    The authors have investigated the pattern of wall deposition and maturation and correlated it with cell expansion and cellulose biosynthesis. The herbicide 2,6-dichlorobenzonitrile (DCB) was found to be a potent inhibitor of cellulose synthesis, but not of cell expansion in Nitella internodal cells. Although cellulose synthesis is inhibited during DCB treatment, matrix substances continue to be synthesized and deposited. The inhibition of cellulose microfibril deposition can be demonstrated by various techniques. These results demonstrate that matrix deposition is by apposition, not by intussusception, and that the previously deposited wall moves progressively outward while stretching and thinning as a result of cell expansion

  3. Molecular-cytogenetic aberrations in B-cell adult acute lymphoblastic leukemia (B-ALL) - frequency and correlation with immunophenotype.

    Science.gov (United States)

    Velizarova, Milena; Popova, Dora; Hadjiev, Evgenii; Aleksandrova, Kamelia; Dimova, Ivanka; Zaharieva, Boriana; Toshkov, Stavri; Staneva, Mimoza; Hodjajik, Djansaran; Penev, Marin; Toncheva, Draga

    2006-09-05

    B-cell acute lymphoblastic leukemia (B-ALL) accounts for 20-30% of acute leukemias in adults. Combined application of data from immunophenotyping, karyotyping and molecular analyses allows a better understanding of this heterogeneous disease. We studied 30 adult patients with newly diagnosed B-ALL by conventional cytogenetics, fluorescent in situ hybridization (FISH) and immunophenotyping analyses. We report statistically significant prevalence of structural aberrations (43%) over numerical changes (17%) (p=0.02). The most frequent structural changes were t(9;22)(q34;q11)/bcr-abl-17%, t(8q24)/C-MYC-10%, t(11q23)/MLL-6%, del 4p-6%, del12p-3%, and t(1;19)-3%. Complex karyotype was found in 17% and normal karyotype in 30%. The most frequent immunophenotype was of common B-ALL (43%), and cytogenetic and/or molecular abnormalities were found in 78% of them. We distinguished a relatively high incidence (17%) of mature B-ALL and 60% of them were associated with t(8;14)/C-MYC. We established association of cytogenetic aberrations with immunophenotype only in mature B-ALL. The other immunophenotypes are characterized by genetic heterogeneity and the presence of cytogenetic abnormalities unusual for adult B-ALL - trisomy 8 and t(1;19)(q23;p13).

  4. Binding of 18F by cell membranes and cell walls of Streptococcus mutans

    International Nuclear Information System (INIS)

    Yotis, W.W.; Zeb, M.; McNulty, J.; Kirchner, F.; Reilly, C.; Glendenin, L.

    1983-01-01

    The binding of 18 F to isolated cell membranes and cell walls of Streptococcus mutans GS-5 or other bacteria was assayed. The attachment of 18 F to these cell envelopes proceeded slowly and reached equilibrium within 60 min. 18 F binding was stimulated by Ca 2+ (1 mM). The binding of 18 F to cellular components was dependent upon the pH, as well as the amount of 18 F and dose of the binder employed. The binding of 18 F by cell walls prepared from fluoride-sensitive and fluoride-resistant cells of S. salivarius and S. mutans did not differ significantly. The pretreatment of cell walls or cell membranes for 60 min at 30 degrees C with 1 mg of RNase, DNase, or trypsin per ml did not influence the binding of 18 F by the walls and membranes of S. mutans GS-5. However, prior exposure of cell membranes to sodium dodecyl sulfate caused a significant reduction in the number of 18 F atoms bound by the membranes. In saturated assay systems, cell membranes of S. mutans GS-5 bound 10(15) to 10(16) atoms of 18 F per mg (dry weight), whereas cell walls from S. mutans GS-5, FA-1, and HS-6 or Actinomyces viscosus T14V and T14AV bound 10(12) to 10(13) atoms of 18 F per mg (dry weight). 18 F in this quantity (10(12) to 10(13) atoms) cannot be detected with the fluoride electrode. The data provide, for the first time, a demonstration of 18 F binding by cell membranes and walls of oral flora

  5. Dual Targeting of Cell Wall Precursors by Teixobactin Leads to Cell Lysis

    Science.gov (United States)

    Homma, Tomoyuki; Nuxoll, Austin; Gandt, Autumn Brown; Ebner, Patrick; Engels, Ina; Schneider, Tanja; Götz, Friedrich; Lewis, Kim

    2016-01-01

    Teixobactin represents the first member of a newly discovered class of antibiotics that act through inhibition of cell wall synthesis. Teixobactin binds multiple bactoprenol-coupled cell wall precursors, inhibiting both peptidoglycan and teichoic acid synthesis. Here, we show that the impressive bactericidal activity of teixobactin is due to the synergistic inhibition of both targets, resulting in cell wall damage, delocalization of autolysins, and subsequent cell lysis. We also find that teixobactin does not bind mature peptidoglycan, further increasing its activity at high cell densities and against vancomycin-intermediate Staphylococcus aureus (VISA) isolates with thickened peptidoglycan layers. These findings add to the attractiveness of teixobactin as a potential therapeutic agent for the treatment of infection caused by antibiotic-resistant Gram-positive pathogens. PMID:27550357

  6. A Clostridium difficile Cell Wall Glycopolymer Locus Influences Bacterial Shape, Polysaccharide Production and Virulence.

    Directory of Open Access Journals (Sweden)

    Michele Chu

    2016-10-01

    Full Text Available Clostridium difficile is a diarrheagenic pathogen associated with significant mortality and morbidity. While its glucosylating toxins are primary virulence determinants, there is increasing appreciation of important roles for non-toxin factors in C. difficile pathogenesis. Cell wall glycopolymers (CWGs influence the virulence of various pathogens. Five C. difficile CWGs, including PSII, have been structurally characterized, but their biosynthesis and significance in C. difficile infection is unknown. We explored the contribution of a conserved CWG locus to C. difficile cell-surface integrity and virulence. Attempts at disrupting multiple genes in the locus, including one encoding a predicted CWG exporter mviN, were unsuccessful, suggesting essentiality of the respective gene products. However, antisense RNA-mediated mviN downregulation resulted in slight morphology defects, retarded growth, and decreased surface PSII deposition. Two other genes, lcpA and lcpB, with putative roles in CWG anchoring, could be disrupted by insertional inactivation. lcpA- and lcpB- mutants had distinct phenotypes, implying non-redundant roles for the respective proteins. The lcpB- mutant was defective in surface PSII deposition and shedding, and exhibited a remodeled cell surface characterized by elongated and helical morphology, aberrantly-localized cell septae, and an altered surface-anchored protein profile. Both lcpA- and lcpB- strains also displayed heightened virulence in a hamster model of C. difficile disease. We propose that gene products of the C. difficile CWG locus are essential, that they direct the production/assembly of key antigenic surface polysaccharides, and thereby have complex roles in virulence.

  7. Penium margaritaceum: A Unicellular Model Organism for Studying Plant Cell Wall Architecture and Dynamics

    Directory of Open Access Journals (Sweden)

    David S. Domozych

    2014-11-01

    Full Text Available Penium margaritaceum is a new and valuable unicellular model organism for studying plant cell wall structure and developmental dynamics. This charophyte has a cell wall composition remarkably similar to the primary cell wall of many higher plants and clearly-defined inclusive zones containing specific polymers. Penium has a simple cylindrical phenotype with a distinct region of focused wall synthesis. Specific polymers, particularly pectins, can be identified using monoclonal antibodies raised against polymers of higher plant cell walls. Immunofluorescence-based labeling is easily performed using live cells that subsequently can be returned to culture and monitored. This feature allows for rapid assessment of wall expansion rates and identification of multiple polymer types in the wall microarchitecture during the cell cycle. Cryofixation by means of spray freezing provides excellent transmission electron microscopy imaging of the cell, including its elaborate endomembrane and cytoskeletal systems, both integral to cell wall development. Penium’s fast growth rate allows for convenient microarray screening of various agents that alter wall biosynthesis and metabolism. Finally, recent successful development of transformed cell lines has allowed for non-invasive imaging of proteins in cells and for RNAi reverse genetics that can be used for cell wall biosynthesis studies.

  8. Penium margaritaceum: A Unicellular Model Organism for Studying Plant Cell Wall Architecture and Dynamics.

    Science.gov (United States)

    Domozych, David S

    2014-11-18

    Penium margaritaceum is a new and valuable unicellular model organism for studying plant cell wall structure and developmental dynamics. This charophyte has a cell wall composition remarkably similar to the primary cell wall of many higher plants and clearly-defined inclusive zones containing specific polymers. Penium has a simple cylindrical phenotype with a distinct region of focused wall synthesis. Specific polymers, particularly pectins, can be identified using monoclonal antibodies raised against polymers of higher plant cell walls. Immunofluorescence-based labeling is easily performed using live cells that subsequently can be returned to culture and monitored. This feature allows for rapid assessment of wall expansion rates and identification of multiple polymer types in the wall microarchitecture during the cell cycle. Cryofixation by means of spray freezing provides excellent transmission electron microscopy imaging of the cell, including its elaborate endomembrane and cytoskeletal systems, both integral to cell wall development. Penium's fast growth rate allows for convenient microarray screening of various agents that alter wall biosynthesis and metabolism. Finally, recent successful development of transformed cell lines has allowed for non-invasive imaging of proteins in cells and for RNAi reverse genetics that can be used for cell wall biosynthesis studies.

  9. The Role of Pectin Acetylation in the Organization of Plant Cell Walls

    DEFF Research Database (Denmark)

    Fimognari, Lorenzo

    All plant cells are surrounded by one or more cell wall layers. The cell wall serves as a stiff mechanical support while it allows cells to expand and provide a protective barrier to invading pathogens. Cell walls are dynamic structures composed of entangled cell wall polysaccharides that must...... adopt defined 3D organization to allow their composition/interactions to be tweaked upon developmental need. Failure to build functional cell wall architecture will affect plant growth and resistance to stresses. In this PhD dissertation I explored the role of pectin acetylation in controlling...... that the loss of structural integrity in the cell wall was the underlying cause for triggering defenses response. This hypothesis was tested in Manuscript II. Through a suppressor screen of 30.000 Arabidopsis rwa2 plants and mapping of mutations by next generation sequencing, we pinpointed pectin deacetylation...

  10. Effects of turmeric and its active principle, curcumin, on bleomycin-induced chromosome aberrations in Chinese hamster ovary cells

    Directory of Open Access Journals (Sweden)

    Araújo Maria Cristina P.

    1999-01-01

    Full Text Available Naturally occurring antioxidants have been extensively studied for their capacity to protect organisms and cells from oxidative damage. Many plant constituents including turmeric and curcumin appear to be potent antimutagens and antioxidants. The effects of turmeric and curcumin on chromosomal aberration frequencies induced by the radiomimetic agent bleomycin (BLM were investigated in Chinese hamster ovary (CHO cells. Three concentrations of each drug, turmeric (100, 250 and 500 mg/ml and curcumin (2.5, 5 and 10 mg/ml, were combined with BLM (10 mg/ml in CHO cells treated during the G1/S, S or G2/S phases of the cell cycle. Neither turmeric nor curcumin prevented BLM-induced chromosomal damage in any phases of the cell cycle. Conversely, a potentiation of the clastogenicity of BLM by curcumin was clearly observed in cells treated during the S and G2/S phases. Curcumin was also clastogenic by itself at 10 µg/ml in two protocols used. However, the exact mechanism by which curcumin produced clastogenic and potentiating effects remains unknown.

  11. Murein and pseudomurein cell wall binding domains of bacteria and archaea-a comparative view

    NARCIS (Netherlands)

    Visweswaran, Ganesh Ram R.; Dijkstra, Bauke W.; Kok, Jan

    2011-01-01

    The cell wall, a major barrier protecting cells from their environment, is an essential compartment of both bacteria and archaea. It protects the organism from internal turgor pressure and gives a defined shape to the cell. The cell wall serves also as an anchoring surface for various proteins and

  12. Investigation of microstructural and mechanical properties of cell walls of closed-cell aluminium alloy foams

    Energy Technology Data Exchange (ETDEWEB)

    Islam, M.A.; Kader, M.A.; Hazell, P.J.; Brown, A.D. [School of Engineering and Information Technology, UNSW Canberra, ACT 2610 (Australia); Saadatfar, M. [Department of Applied Mathematics, Australian National University, Canberra ACT 0200 (Australia); Quadir, M.Z [Electron Microscope Unit, Mark Wainwright Analytical Centre (MWAC), The University of New South Wales, Sydney, NSW 2052 (Australia); Microscopy and Microanalysis Facility (MMF), John de Laeter Centre (JdLC), Curtin University, WA 6102 (Australia); Escobedo, J.P., E-mail: J.Escobedo-Diaz@adfa.edu.au [School of Engineering and Information Technology, UNSW Canberra, ACT 2610 (Australia)

    2016-06-01

    This study investigates the influence of microstructure on the strength properties of individual cell walls of closed-cell stabilized aluminium foams (SAFs). Optical microscopy (OM), micro-computed X-ray tomography (µ-CT), electron backscattering diffraction (EBSD), and energy dispersive X-ray spectroscopy (EDS) analyses were conducted to examine the microstructural properties of SAF cell walls. Novel micro-tensile tests were performed to investigate the strength properties of individual cell walls. Microstructural analysis of the SAF cell walls revealed that the material consists of eutectic Al-Si and dendritic a-Al with an inhomogeneous distribution of intermetallic particles and micro-pores (void defects). These microstructural features affected the micro-mechanism fracture behaviour and tensile strength of the specimens. Laser-based extensometer and digital image correlation (DIC) analyses were employed to observe the strain fields of individual tensile specimens. The tensile failure mode of these materials has been evaluated using microstructural analysis of post-mortem specimens, revealing a brittle cleavage fracture of the cell wall materials. The micro-porosities and intermetallic particles reduced the strength under tensile loading, limiting the elongation to fracture on average to ~3.2% and an average ultimate tensile strength to ~192 MPa. Finally, interactions between crack propagation and obstructing intermetallic compounds during the tensile deformation have been elucidated.

  13. Binding of paraquat to cell walls of paraquat resistant and susceptible biotypes of Hordeum glaucum

    International Nuclear Information System (INIS)

    Alizadeh, H.M.; Preston, C.; Powles, S.B.

    1997-01-01

    Full text: Paraquat is a widely used, non-selective, light activated contact herbicide acting as a photosystem electron acceptor. Resistance to paraquat in weed species has occurred in Australia and world-wide following extensive use of this herbicide. The mechanism of resistance to paraquat in 'Hordeum glaucum' is correlated with reduced herbicide translocation and may be due to sequestration of herbicide away from its site of action by either binding to cell walls or other means. We measured paraquat binding to a cell wall fraction in resistant and susceptible biotypes of H. glaucum to determine whether differences in binding of paraquat to cell walls could explain herbicide resistance. The cell wall fraction was isolated from leaves of resistant and susceptible biotypes and incubated with 14 C-labelled paraquat. Of the total paraquat - absorbed by a cell wall preparation, about 80% remains strongly bind to the cell wall and doesn't readily exchange with solution in the absence of divalent cations. Divalent cations (Ca 2+ ,putrescine and paraquat) can competitively exchange for paraquat tightly bound to the cell wall. From kinetic experiments it seems that there are two types of binding sites in the cell wall with different affinities for paraquat. No significant differences between cell wall, characteristics of resistant and susceptible biotypes of H. glaucum have been found in any of our experiments. Therefore, increased binding of paraquat to the cell wall appears not to be a mechanism for exclusion of paraquat in resistant biotype

  14. Aberrant prostaglandin synthase 2 expression defines an antigen-presenting cell defect for insulin-dependent diabetes mellitus

    Science.gov (United States)

    Litherland, S.A.; Xie, X.T.; Hutson, A.D.; Wasserfall, C.; Whittaker, D.S.; She, J.-X.; Hofig, A.; Dennis, M.A.; Fuller, K.; Cook, R.; Schatz, D.; Moldawer, L.L.; Clare-Salzler, M.J.

    1999-01-01

    Prostaglandins (PGs) are lipid molecules that profoundly affect cellular processes including inflammation and immune response. Pathways contributing to PG output are highly regulated in antigen-presenting cells such as macrophages and monocytes, which produce large quantities of these molecules upon activation. In this report, we demonstrate aberrant constitutive expression of the normally inducible cyclooxygenase PG synthase 2 (PGS2/ COX-2) in nonactivated monocytes of humans with insulin-dependent diabetes mellitus (IDDM) and those with islet autoantibodies at increased risk of developing this disease. Constitutive PGS2 appears to characterize a high risk for diabetes as it correlates with and predicts a low first-phase insulin response in autoantibody-positive subjects. Abnormal PGS2 expression in at-risk subjects affected immune response in vitro, as the presence of a specific PGS2 inhibitor, NS398, significantly increased IL-2 receptor α-chain (CD25) expression on phytohemagglutinin-stimulated T cells. The effect of PGS2 on CD25 expression was most profound in subjects expressing both DR04 and DQβ0302 high-risk alleles, suggesting that this cyclooxygenase interacts with diabetes-associated MHC class II antigens to limit T-cell activation. These results indicate that constitutive PGS2 expression in monocytes defines an antigen-presenting cell defect affecting immune response, and that this expression is a novel cell-associated risk marker for IDDM. J. Clin. Invest. 104:515-523 (1999). PMID:10449443

  15. Suppressing effect of antimutagenic flavorings on chromosome aberrations induced by UV-light or X-rays in cultured Chinese hamster cells

    International Nuclear Information System (INIS)

    Sasaki, Yu.F.; Imanishi, Hisako; Watanabe, Mie; Ohta, Toshihiro; Shirasu

    1990-01-01

    Chromosome aberrations induces by UV-light or X-rays were suppressed by the post-treatment with antimutagenic flavorings, such as anisaldehyde, cinnamaldehyde, coumarin, and vanillin. UV- or X-ray-irradiated surviving cells increased in the presence of each flavouring. X-ray-induced breakage-type and exchange-type chromosome aberrations were suppressed by the vanillin treatment in the G 1 phase of the cell cycle and a greater decrease in the number of X-ray-induced chromosome aberrations during G 1 holding was observed in the presence of vanillin. Furthermore, a greater decrease in the number of X-ray-induced DNA single-strand breaks was observed in the presence of vanillin. Treatment with vanillin in the G 2 phase suppressed UV-and X-ray-induced breakage-type but not exchange-type chromosome aberrations. The suppression of breakage-type aberrations was assumed to be due to a modification of the capability of the post-replicational repair of DNA double-strand breaks. (author). 28 refs.; 5 figs.; 6 tabs

  16. Immunogold scanning electron microscopy can reveal the polysaccharide architecture of xylem cell walls.

    Science.gov (United States)

    Sun, Qiang; Sun, Yuliang; Juzenas, Kevin

    2017-04-01

    Immunofluorescence microscopy (IFM) and immunogold transmission electron microscopy (TEM) are the two main techniques commonly used to detect polysaccharides in plant cell walls. Both are important in localizing cell wall polysaccharides, but both have major limitations, such as low resolution in IFM and restricted sample size for immunogold TEM. In this study, we have developed a robust technique that combines immunocytochemistry with scanning electron microscopy (SEM) to study cell wall polysaccharide architecture in xylem cells at high resolution over large areas of sample. Using multiple cell wall monoclonal antibodies (mAbs), this immunogold SEM technique reliably localized groups of hemicellulosic and pectic polysaccharides in the cell walls of five different xylem structures (vessel elements, fibers, axial and ray parenchyma cells, and tyloses). This demonstrates its important advantages over the other two methods for studying cell wall polysaccharide composition and distribution in these structures. In addition, it can show the three-dimensional distribution of a polysaccharide group in the vessel lateral wall and the polysaccharide components in the cell wall of developing tyloses. This technique, therefore, should be valuable for understanding the cell wall polysaccharide composition, architecture and functions of diverse cell types. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. The role of cell walls and pectins in cation exchange and surface area of plant roots.

    Science.gov (United States)

    Szatanik-Kloc, A; Szerement, J; Józefaciuk, G

    2017-08-01

    We aimed to assess role of cell walls in formation of cation exchange capacity, surface charge, surface acidity, specific surface, water adsorption energy and surface charge density of plant roots, and to find the input of the cell wall pectins to the above properties. Whole roots, isolated cell walls and the residue after the extraction of pectins from the cell walls of two Apiaceae L. species (celeriac and parsnip) were studied using potentiometric titration curves and water vapor adsorption - desorption isotherms. Total amount of surface charge, as well as the cation exchange capacity were markedly higher in roots than in their cell walls, suggesting large contribution of other cell organelles to the binding of cations by the whole root cells. Significantly lower charge of the residues after removal of pectins was noted indicating that pectins play the most important role in surface charge formation of cell walls. The specific surface was similar for all of the studied materials. For the separated cell walls it was around 10% smaller than of the whole roots, and it increased slightly after the removal of pectins. The surface charge density and water vapor adsorption energy were the highest for the whole roots and the lowest for the cell walls residues after removal of pectins. The results indicate that the cell walls and plasma membranes are jointly involved in root ion exchange and surface characteristics and their contribution depends upon the plant species. Copyright © 2017 Elsevier GmbH. All rights reserved.

  18. Structural constraints and dynamics of bacterial cell wall architecture

    Directory of Open Access Journals (Sweden)

    Miguel Angel De Pedro

    2015-05-01

    Full Text Available The peptidoglycan wall (PG is a unique structure which confers physical strength and defined shape to bacteria. It consists of a net-like macromolecule of peptide interlinked glycan chains overlying the cell membrane. The structure and layout of the PG dictates that the wall has to be continuously modified as bacteria go through division, morphological differentiation and adaptive responses. The PG is poorly known in structural terms. However, to understand morphogenesis a precise knowledge of glycan strand arrangement and of local effects of the different kinds of subunits is essential. The scarcity of data led to a conception of the PG as a regular, highly ordered structure which strongly influenced growth models. Here, we review the structure of the PG to define a more realistic conceptual framework. We discuss the consequences of the plasticity of murein architecture in morphogenesis and try to define a set of minimal structural constraints that must be fulfilled by any model to be compatible with present day information.

  19. Identifying cytoplasmic input to the cell wall of growing Chara corallina.

    Science.gov (United States)

    Proseus, Timothy E; Boyer, John S

    2006-01-01

    Plants enlarge mostly because the walls of certain cells enlarge, with accompanying input of wall constituents and other factors from the cytoplasm. However, the enlargement can occur without input, suggesting an uncertain relationship between cytoplasmic input and plant growth. Therefore, the role of the input was investigated by quantitatively comparing growth in isolated walls (no input) with that in living cells (input occurring). Cell walls were isolated from growing internodes of Chara corallina and filled with pressurized oil to control turgor pressure while elongation was monitored. Turgor pressure in living cells was similarly controlled and monitored by adding/removing cell solution. Temperature was varied in some experiments. At all pressures and temperatures, isolated walls displayed turgor-driven growth indistinguishable in every respect from that in living cells, except the rate decelerated in the isolated walls while the living cells grew rapidly. The growth in the isolated walls was highly responsive to temperature, in contrast to the elastic extension that has been shown to be insensitive to similar temperatures. Consequently, strong intermolecular bonds were responsible for growth and weak bonds for elastic extension. Boiling the walls gave the same results, indicating that enzyme activities were not controlling these bonds. However, pectin added to isolated walls reversed their growth deceleration and returned the rate to that in the living cells. The pectin was similar to that normally produced by the cytoplasm and deposited in the wall, suggesting that continued cytoplasmic input of pectin may play a role in sustaining turgor-driven growth in Chara.

  20. Genome-wide analysis of cell wall-related genes in Tuber melanosporum.

    Science.gov (United States)

    Balestrini, Raffaella; Sillo, Fabiano; Kohler, Annegret; Schneider, Georg; Faccio, Antonella; Tisserant, Emilie; Martin, Francis; Bonfante, Paola

    2012-06-01

    A genome-wide inventory of proteins involved in cell wall synthesis and remodeling has been obtained by taking advantage of the recently released genome sequence of the ectomycorrhizal Tuber melanosporum black truffle. Genes that encode cell wall biosynthetic enzymes, enzymes involved in cell wall polysaccharide synthesis or modification, GPI-anchored proteins and other cell wall proteins were identified in the black truffle genome. As a second step, array data were validated and the symbiotic stage was chosen as the main focus. Quantitative RT-PCR experiments were performed on 29 selected genes to verify their expression during ectomycorrhizal formation. The results confirmed the array data, and this suggests that cell wall-related genes are required for morphogenetic transition from mycelium growth to the ectomycorrhizal branched hyphae. Labeling experiments were also performed on T. melanosporum mycelium and ectomycorrhizae to localize cell wall components.

  1. Individual and combined effects of ochratoxin A and citrinin on viability and DNA fragmentation in cultured Vero cells and on chromosome aberrations in mice bone marrow cells

    International Nuclear Information System (INIS)

    Bouslimi, Amel; Bouaziz, Chayma; Ayed-Boussema, Imen; Hassen, Wafa; Bacha, Hassen

    2008-01-01

    Ochratoxin A (OTA) and citrinin (CTN) are two common contaminant mycotoxins which can occur jointly in a wide range of food commodities. Both mycotoxins have several toxic effects but share a significant nephrotoxic and carcinogenic potential since OTA and CTN were reported to be responsible for naturally occurring human and animal kidney diseases and tumors. Considering the concomitant production of OTA and CTN, it is very likely that humans and animals are always exposed to the mixture rather than to individual compounds. Therefore, the aim of the present study was to investigate, in vivo and in vitro, whether DNA damage is enhanced by combination of both mycotoxins as compared to their effect separately. To this end, we have assessed their effects individually or combined on cell proliferation and DNA fragmentation in cultured Vero cells and in vivo by monitoring the induction of chromosome aberrations. Our results clearly showed that cultured renal cells respond to OTA and CTN exposure by a moderate and weak inhibition of cell proliferation, respectively. However, when combined, they exert a significant increase in inhibition of cell viability. Similar results were found for the investigated genotoxicity endpoints (DNA fragmentation and chromosome aberrations). Altogether, our study showed that OTA and CTN combination effects are clearly synergistic. The synergistic induction of DNA damage observed with OTA and CTN taken concomitantly could be relevant to explain the molecular basis of the renal diseases and tumorogenesis induced by naturally occurring mycotoxins

  2. Secondary cell wall formation in Cryptococcus neoformans as a rescue mechanism against acid-induced autolysis.

    Science.gov (United States)

    Farkas, Vladimír; Takeo, Kanji; Maceková, Danka; Ohkusu, Misako; Yoshida, Soichi; Sipiczki, Matthias

    2009-03-01

    Growth of the opportunistic yeast pathogen Cryptococcus neoformans in a synthetic medium containing yeast nitrogen base and 1.0-3.0% glucose is accompanied by spontaneous acidification of the medium, with its pH decreasing from the initial 5.5 to around 2.5 in the stationary phase. During the transition from the late exponential to the stationary phase of growth, many cells died as a consequence of autolytic erosion of their cell walls. Simultaneously, there was an increase in an ecto-glucanase active towards beta-1,3-glucan and having a pH optimum between pH 3.0 and 3.5. As a response to cell wall degradation, some cells developed an unusual survival strategy by forming 'secondary' cell walls underneath the original ones. Electron microscopy revealed that the secondary cell walls were thicker than the primary ones, exposing bundles of polysaccharide microfibrils only partially masked by an amorphous cell wall matrix on their surfaces. The cells bearing secondary cell walls had a three to five times higher content of the alkali-insoluble cell wall polysaccharides glucan and chitin, and their chitin/glucan ratio was about twofold higher than in cells from the logarithmic phase of growth. The cell lysis and the formation of the secondary cell walls could be suppressed by buffering the growth medium between pH 4.5 and 6.5.

  3. In-situ Raman microprobe studies of plant cell walls: macromolecular organization and compositional variability in the secondary wall of Picea mariana (Mill.) B.S.P.

    Science.gov (United States)

    U.P. Agarwal; R.H. Atalla

    1986-01-01

    Native-state organization and distribution of cell-wall components in the secondary wall of woody tissue from P. mariana (Black Spruce) have been investigated using polarized Raman microspectroscopy. Evidence for orientation is detected through Raman intensity variations resulting from rotations of the exciting electric vector with respect to cell-wall geometry....

  4. Laccases Direct Lignification in the Discrete Secondary Cell Wall Domains of Protoxylem1[W][OPEN

    Science.gov (United States)

    Schuetz, Mathias; Benske, Anika; Smith, Rebecca A.; Watanabe, Yoichiro; Tobimatsu, Yuki; Ralph, John; Demura, Taku; Ellis, Brian; Samuels, A. Lacey

    2014-01-01

    Plants precisely control lignin deposition in spiral or annular secondary cell wall domains during protoxylem tracheary element (TE) development. Because protoxylem TEs function to transport water within rapidly elongating tissues, it is important that lignin deposition is restricted to the secondary cell walls in order to preserve the plasticity of adjacent primary wall domains. The Arabidopsis (Arabidopsis thaliana) inducible VASCULAR NAC DOMAIN7 (VND7) protoxylem TE differentiation system permits the use of mutant backgrounds, fluorescent protein tagging, and high-resolution live-cell imaging of xylem cells during secondary cell wall development. Enzymes synthesizing monolignols, as well as putative monolignol transporters, showed a uniform distribution during protoxylem TE differentiation. By contrast, the oxidative enzymes LACCASE4 (LAC4) and LAC17 were spatially localized to secondary cell walls throughout protoxylem TE differentiation. These data support the hypothesis that precise delivery of oxidative enzymes determines the pattern of cell wall lignification. This view was supported by lac4lac17 mutant analysis demonstrating that laccases are necessary for protoxylem TE lignification. Overexpression studies showed that laccases are sufficient to catalyze ectopic lignin polymerization in primary cell walls when exogenous monolignols are supplied. Our data support a model of protoxylem TE lignification in which monolignols are highly mobile once exported to the cell wall, and in which precise targeting of laccases to secondary cell wall domains directs lignin deposition. PMID:25157028

  5. Laccases direct lignification in the discrete secondary cell wall domains of protoxylem.

    Science.gov (United States)

    Schuetz, Mathias; Benske, Anika; Smith, Rebecca A; Watanabe, Yoichiro; Tobimatsu, Yuki; Ralph, John; Demura, Taku; Ellis, Brian; Samuels, A Lacey

    2014-10-01

    Plants precisely control lignin deposition in spiral or annular secondary cell wall domains during protoxylem tracheary element (TE) development. Because protoxylem TEs function to transport water within rapidly elongating tissues, it is important that lignin deposition is restricted to the secondary cell walls in order to preserve the plasticity of adjacent primary wall domains. The Arabidopsis (Arabidopsis thaliana) inducible VASCULAR NAC DOMAIN7 (VND7) protoxylem TE differentiation system permits the use of mutant backgrounds, fluorescent protein tagging, and high-resolution live-cell imaging of xylem cells during secondary cell wall development. Enzymes synthesizing monolignols, as well as putative monolignol transporters, showed a uniform distribution during protoxylem TE differentiation. By contrast, the oxidative enzymes LACCASE4 (LAC4) and LAC17 were spatially localized to secondary cell walls throughout protoxylem TE differentiation. These data support the hypothesis that precise delivery of oxidative enzymes determines the pattern of cell wall lignification. This view was supported by lac4lac17 mutant analysis demonstrating that laccases are necessary for protoxylem TE lignification. Overexpression studies showed that laccases are sufficient to catalyze ectopic lignin polymerization in primary cell walls when exogenous monolignols are supplied. Our data support a model of protoxylem TE lignification in which monolignols are highly mobile once exported to the cell wall, and in which precise targeting of laccases to secondary cell wall domains directs lignin deposition. © 2014 American Society of Plant Biologists. All Rights Reserved.

  6. A Survey of Databases for Analysis of Plant Cell Wall-Related Enzymes

    OpenAIRE

    Cao, Peijian; Jung, Ki-Hong; Ronald, Pamela C

    2010-01-01

    Biofuels derived from plant cell wall lignocellulose have the potential to serve as an alternative source of energy, relieving dependence on finite petroleum reserves and reducing production of climate-changing greenhouse gases. To better elucidate cell wall structure, the plant research community has developed databases to host the accumulated information on plant cell wall-related enzymes. The goal of this review is to provide a comprehensive catalog of these databases, as well as to descri...

  7. Synergistic Effects of Cellulosomal Xylanase and Cellulases from Clostridium cellulovorans on Plant Cell Wall Degradation

    OpenAIRE

    Murashima, Koichiro; Kosugi, Akihiko; Doi, Roy H.

    2003-01-01

    Plant cell walls are comprised of cellulose and hemicellulose and other polymers that are intertwined, and this complex structure presents a barrier to degradation by pure cellulases or hemicellulases. In this study, we determined the synergistic effects on corn cell wall degradation by the action of cellulosomal xylanase XynA and cellulosomal cellulases from Clostridium cellulovorans. XynA minicellulosomes and cellulase minicellulosomes were found to degrade corn cell walls synergistically b...

  8. Characterization of nonderivatized plant cell walls using high-resolution solution-state NMR spectroscopy

    Science.gov (United States)

    Daniel J. Yelle; John Ralph; Charles R. Frihart

    2008-01-01

    A recently described plant cell wall dissolution system has been modified to use perdeuterated solvents to allow direct in-NMR-tube dissolution and high-resolution solution-state NMR of the whole cell wall without derivatization. Finely ground cell wall material dissolves in a solvent system containing dimethylsulfoxide-d6 and 1-methylimidazole-d6 in a ratio of 4:1 (v/...

  9. The Cell Walls of Green Algae: A Journey through Evolution and Diversity

    OpenAIRE

    Domozych, David S.; Ciancia, Marina; Fangel, Jonatan U.; Mikkelsen, Maria Dalgaard; Ulvskov, Peter; Willats, William G. T.

    2012-01-01

    The green algae represent a large group of morphologically diverse photosynthetic eukaryotes that occupy virtually every photic habitat on the planet. The extracellular coverings of green algae including cell walls are also diverse. A recent surge of research in green algal cell walls fueled by new emerging technologies has revealed new and critical insight concerning these coverings. For example, the late divergent taxa of the Charophycean Green Algae possess cell walls containing assemblag...

  10. Fate of mucilage cell wall polysaccharides during coffee fermentation.

    Science.gov (United States)

    Avallone, S; Guiraud, J P; Guyot, B; Olguin, E; Brillouet, J M

    2001-11-01

    Effects of a 20-h fermentation on cell wall polysaccharides from the mucilage of pulped coffee beans were examined and compared to those of unfermented beans, on alcohol insoluble residues (AIRs), their hot-water-soluble crude pectic substances (PECTs), and their hot-water-insoluble residues (RESs). Yields and compositions were very similar: AIRs, which consisted of approximately 30% highly methylated pectic substances, approximately 9% cellulose, and approximately 15% neutral noncellulosic polysaccharides, exhibited no apparent degradation. However, PECTs from fermented beans were shown to have undergone a slight reduction of their intrinsic viscosity and weight-average molecular weight by capillary viscosimetry and high-performance size-exclusion chromatography. After fermentation, hot-water-insoluble pectic substances of RES exhibited partial de-esterification. Removal of coffee bean mucilage by natural fermentation seems to result from a restricted pectolysis, the mechanism of which remains to be elucidated.

  11. Composition and architecture of the cell walls of grasses and the mechanisms of synthesis of cell wall polysaccharides. Final report for period September 1, 1988 - April 30, 2001

    Energy Technology Data Exchange (ETDEWEB)

    Carpita, Nicholas C.

    2001-10-18

    This program was devoted toward complete understanding of the polysaccharide structure and architecture of the primary cell walls grasses and cereals, and the biosynthesis of the mixed-linkage beta-glucane, a cellulose interacting polymer that is synthesized uniquely by grass species and close relatives. With these studies as focal point, the support from DOE was instrumental in the development of new analytical means that enabled us to characterize carbohydrate structure, to reveal new features of cell wall dynamics during cell growth, and to apply these techniques in other model organisms. The support by DOE in these basic studies was acknowledged on numerous occasions in review articles covering current knowledge of cell wall structure, architecture, dynamics, biosynthesis, and in all genes related to cell wall biogenesis.

  12. Cell Walls of Wood, Composition, Structure and a few Mechanical Properties

    OpenAIRE

    Florentina Adriana Cziple; António J. Velez Marques

    2008-01-01

    The objective of this paper was to investigate the effect between the chemical composition, molecular architecture and structure cell walls of wood and the mechanical properties of wood. Cell walls function as the major mechanical restraint that determines plant cell size and morphology.

  13. Pectinous cell wall thickenings formation - A common defense strategy of plants to cope with Pb.

    Science.gov (United States)

    Krzesłowska, Magdalena; Rabęda, Irena; Basińska, Aneta; Lewandowski, Michał; Mellerowicz, Ewa J; Napieralska, Anna; Samardakiewicz, Sławomir; Woźny, Adam

    2016-07-01

    Lead, one of the most abundant and hazardous trace metals affecting living organisms, has been commonly detected in plant cell walls including some tolerant plants, mining ecotypes and hyperaccumulators. We have previously shown that in tip growing Funaria sp. protonemata cell wall is remodeled in response to lead by formation of thickenings rich in low-methylesterified pectins (pectin epitope JIM5 - JIM5-P) able to bind metal ions, which accumulate large amounts of Pb. Hence, it leads to the increase of cell wall capacity for Pb compartmentalization. Here we show that diverse plant species belonging to different phyla (Arabidopsis, hybrid aspen, star duckweed), form similar cell wall thickenings in response to Pb. These thickenings are formed in tip growing cells such as the root hairs, and in diffuse growing cells such as meristematic and root cap columella cells of root apices in hybrid aspen and Arabidopsis and in mesophyll cells in star duckweed fronds. Notably, all analyzed cell wall thickenings were abundant in JIM5-P and accumulated high amounts of Pb. In addition, the co-localization of JIM5-P and Pb commonly occurred in these cells. Hence, cell wall thickenings formed the extra compartment for Pb accumulation. In this way plant cells increased cell wall capacity for compartmentalization of this toxic metal, protecting protoplast from its toxicity. As cell wall thickenings occurred in diverse plant species and cell types differing in the type of growth we may conclude that pectinous cell wall thickenings formation is a widespread defense strategy of plants to cope with Pb. Moreover, detection of natural defense strategy, increasing plant cell walls capacity for metal accumulation, reveals a promising direction for enhancing plant efficiency in phytoremediation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Antioxidant properties of cell wall polysaccharides of Stevia rebaudiana leaves

    Directory of Open Access Journals (Sweden)

    Mediesse Kengne Francine

    2014-12-01

    Full Text Available Objective: To examine the total phenolic and protein contents, and the antioxidant activities of cell wall polysaccharide fractions of Stevia rebaudiana leaves. Methods: Three different polysaccharide-enriched fractions, namely FPE (extract with 50 mmol/ L ethylene diamine tetra acetic acid, FPK (extract with 0.05 mol/L KOH and FH (extract with 4 mol/L KOH were extracted from Stevia rebaudiana leaves. The antioxidant activity of these fractions was evaluated based on their ability to scavenge DPPH (1, 1-diphenyl-2-picryl hydrazyl free radical, to reduce ferric power, to chelate ferrous ion and to protect human DNA. Results: The results indicated that protein content was found to be higher in FPK polysaccharide enriched fraction (47.48 µg per mg of FPK. Furthermore, the phenolic compound analysis according to the Folin-Ciocalteu method was higher in FPK (17.71 µg ferulic acid. The DPPH maximal inhibition percentage of the three polysaccharide-enriched fractions at 400 µg/mL was 27.66%, 59.90% and 23.21% respectively for FPE, FPK and FH. All the polysaccharide fractions exhibited a ferric reducing power except the FH one. The three fractions also exhibited lipid peroxidation inhibition, and they completely reverted the DNA damage induced by H2O2/FeCl2. FPK showed the strongest scavenging activity against the DPPH radical, the best chelating ability and lipid peroxidation inhibition. Conclusions: Stevia cell wall polysaccharide fractions are potent protective agents against oxidative stress. The analysis revealed major differences in the antioxidant activity in the three polysaccharides fractions. However, the 0.05 mol/L KOH pectin fraction (FPK showed better antioxidant activity.

  15. Structural changes in cell wall pectins during strawberry fruit development.

    Science.gov (United States)

    Paniagua, Candelas; Santiago-Doménech, Nieves; Kirby, Andrew R; Gunning, A Patrick; Morris, Victor J; Quesada, Miguel A; Matas, Antonio J; Mercado, José A

    2017-09-01

    Strawberry (Fragaria × anannasa Duch.) is one of the most important soft fruit. Rapid loss of firmness occurs during the ripening process, resulting in a short shelf life and high economic losses. To get insight into the role of pectin matrix in the softening process, cell walls from strawberry fruit at two developmental stages, unripe-green and ripe-red, were extracted and sequentially fractionated with different solvents to obtain fractions enriched in a specific component. The yield of cell wall material as well as the per fresh weight contents of the different fractions decreased in ripe fruit. The largest reduction was observed in the pectic fractions extracted with a chelating agent (trans-1,2- diaminocyclohexane-N,N,N'N'-tetraacetic acid, CDTA fraction) and those covalently bound to the wall (extracted with Na 2 CO 3 ). Uronic acid content of these two fractions also decreased significantly during ripening, but the amount of soluble pectins extracted with phenol:acetic acid:water (PAW) and water increased in ripe fruit. Fourier transform infrared spectroscopy of the different fractions showed that the degree of esterification decreased in CDTA pectins but increased in soluble fractions at ripen stage. The chromatographic analysis of pectin fractions by gel filtration revealed that CDTA, water and, mainly PAW polyuronides were depolymerised in ripe fruit. By contrast, the size of Na 2 CO 3 pectins was not modified. The nanostructural characteristics of CDTA and Na 2 CO 3 pectins were analysed by atomic force microscopy (AFM). Isolated pectic chains present in the CDTA fractions were significantly longer and more branched in samples from green fruit than those from red fruit. No differences in contour length were observed in Na 2 CO 3 strands between samples of both stages. However, the percentage of branched chains decreased from 19.7% in unripe samples to 3.4% in ripe fruit. The number of pectin aggregates was higher in green fruit samples of both

  16. A high frequency of induction of chromosome aberrations in the bone marrow cells of LEC strain rats by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Okui, Toyo (Hokkaido Inst. of Public Health, Sapporo (Japan)); Hayashi, Masanobu; Watanabe, Tomomasa; Namioka, Shigeo (Dept. of Lab. Animal Science, Hokkaido Univ., Sapporo (Japan)); Endoh, Daiji; Sato, Fumiaki (Dept. of Radiation Biology, Faculty of Veterinary Medicine, Hokkaido Univ., Sapporo (Japan)); Kasai, Noriyuki (Inst. for Animal Experimentation, Hokkaido Univ., Sapporo (Japan))

    1994-08-01

    LEC strain rats, which have been known to develop hereditarily spontaneous fulminant hepatitis 4 to 5 months after birth, are highly sensitive to whole-body X-irradiation when compared to WKAH strain rats. The present results showed that the frequencies of all types of chromosome aberrations induced by X-irradiation in the bone marrow cells of LEC rats were approximately 2- to 3-fold higher than those of WKAH rats, though no significant difference was observed in the frequency of spontaneous chromosome aberrations between LEC and WKAH rats.

  17. Plant cell walls throughout evolution: towards a molecular understanding of their design principles

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred

    2009-02-16

    Throughout their life, plants typically remain in one location utilizing sunlight for the synthesis of carbohydrates, which serve as their sole source of energy as well as building blocks of a protective extracellular matrix, called the cell wall. During the course of evolution, plants have repeatedly adapted to their respective niche,which is reflected in the changes of their body plan and the specific design of cell walls. Cell walls not only changed throughout evolution but also are constantly remodelled and reconstructed during the development of an individual plant, and in response to environmental stress or pathogen attacks. Carbohydrate-rich cell walls display complex designs, which together with the presence of phenolic polymers constitutes a barrier for microbes, fungi, and animals. Throughout evolution microbes have co-evolved strategies for efficient breakdown of cell walls. Our current understanding of cell walls and their evolutionary changes are limited as our knowledge is mainly derived from biochemical and genetic studies, complemented by a few targeted yet very informative imaging studies. Comprehensive plant cell wall models will aid in the re-design of plant cell walls for the purpose of commercially viable lignocellulosic biofuel production as well as for the timber, textile, and paper industries. Such knowledge will also be of great interest in the context of agriculture and to plant biologists in general. It is expected that detailed plant cell wall models will require integrated correlative multimodal, multiscale imaging and modelling approaches, which are currently underway.

  18. Structural basis of cell wall cleavage by a staphylococcal autolysin.

    Directory of Open Access Journals (Sweden)

    Sebastian Zoll

    2010-03-01

    Full Text Available The major autolysins (Atl of Staphylococcus epidermidis and S. aureus play an important role in cell separation, and their mutants are also attenuated in virulence. Therefore, autolysins represent a promising target for the development of new types of antibiotics. Here, we report the high-resolution structure of the catalytically active amidase domain AmiE (amidase S. epidermidis from the major autolysin of S. epidermidis. This is the first protein structure with an amidase-like fold from a bacterium with a gram-positive cell wall architecture. AmiE adopts a globular fold, with several alpha-helices surrounding a central beta-sheet. Sequence comparison reveals a cluster of conserved amino acids that define a putative binding site with a buried zinc ion. Mutations of key residues in the putative active site result in loss of activity, enabling us to propose a catalytic mechanism. We also identified and synthesized muramyltripeptide, the minimal peptidoglycan fragment that can be used as a substrate by the enzyme. Molecular docking and digestion assays with muramyltripeptide derivatives allow us to identify key determinants of ligand binding. This results in a plausible model of interaction of this ligand not only for AmiE, but also for other PGN-hydrolases that share the same fold. As AmiE active-site mutations also show a severe growth defect, our findings provide an excellent platform for the design of specific inhibitors that target staphylococcal cell separation and can thereby prevent growth of this pathogen.

  19. Enhanced oxidative stress and aberrant mitochondrial biogenesis in human neuroblastoma SH-SY5Y cells during methamphetamine induced apoptosis

    International Nuclear Information System (INIS)

    Wu, C.-W.; Ping, Y.-H.; Yen, J.-C.; Chang, C.-Y.; Wang, S.-F.; Yeh, C.-L.; Chi, C.-W.; Lee, H.-C.

    2007-01-01

    Methamphetamine (METH) is an abused drug that may cause psychiatric and neurotoxic damage, including degeneration of monoaminergic terminals and apoptosis of non-monoaminergic cells in Brain. The cellular and molecular mechanisms underlying these METH-induced neurotoxic effects remain to be clarified. In this study, we performed a time course assessment to investigate the effects of METH on intracellular oxidative stress and mitochondrial alterations in a human dopaminergic neuroblastoma SH-SY5Y cell line. We characterized that METH induces a temporal sequence of several cellular events including, firstly, a decrease in mitochondrial membrane potential within 1 h of the METH treatment, secondly, an extensive decline in mitochondrial membrane potential and increase in the level of reactive oxygen species (ROS) after 8 h of the treatment, thirdly, an increase in mitochondrial mass after the drug treatment for 24 h, and finally, a decrease in mtDNA copy number and mitochondrial proteins per mitochondrion as well as the occurrence of apoptosis after 48 h of the treatment. Importantly, vitamin E attenuated the METH-induced increases in intracellular ROS level and mitochondrial mass, and prevented METH-induced cell death. Our observations suggest that enhanced oxidative stress and aberrant mitochondrial biogenesis may play critical roles in METH-induced neurotoxic effects

  20. Wall extensibility: its nature, measurement and relationship to plant cell growth

    Science.gov (United States)

    Cosgrove, D. J.

    1993-01-01

    Expansive growth of plant cells is controlled principally by processes that loosen the wall and enable it to expand irreversibly. The central role of wall relaxation for cell expansion is reviewed. The most common methods for assessing the extension properties of plant cell walls ( wall extensibility') are described, categorized and assessed critically. What emerges are three fundamentally different approaches which test growing cells for their ability (a) to enlarge at different values of turgor, (b) to induce wall relaxation, and (c) to deform elastically or plastically in response to an applied tensile force. Analogous methods with isolated walls are similarly reviewed. The results of these different assays are related to the nature of plant cell growth and pertinent biophysical theory. I argue that the extensibilities' measured by these assays are fundamentally different from one another and that some are more pertinent to growth than others.

  1. Cell-stage-specific enhancement by caffeine of the frequency of chromatid aberrations induced by X-rays in neutral ganglia of Drosophila melanogaster

    International Nuclear Information System (INIS)

    De Marco, A.; Polani, S.

    1981-01-01

    Caffeine (10 -2 M) induced a high level of chromatid aberrations in neural ganglia of third-instar larvae of Drosophila melanogaster only when it was added to cells in late G 2 and mitotic prophase. No aberrations were observed after treatment in late S-middle G 2 or C-mitosis. We observed that, in these stages, caffeine strongly increased X-ray-induced damage (500 R). This potentiation was quantitatively similar. But it involved all types of aberration after treatment in C-mitosis, and essentially isochromatid deletions and chromatid exhanges after treatment in S-G 2 . Some hypotheses are put forth to explain the possible mechanism of action of caffeine in the potentiation of X-ray-induced damage. (orig.)

  2. Mechanical feedback coordinates cell wall expansion and assembly in yeast mating morphogenesis

    Science.gov (United States)

    2018-01-01

    The shaping of individual cells requires a tight coordination of cell mechanics and growth. However, it is unclear how information about the mechanical state of the wall is relayed to the molecular processes building it, thereby enabling the coordination of cell wall expansion and assembly during morphogenesis. Combining theoretical and experimental approaches, we show that a mechanical feedback coordinating cell wall assembly and expansion is essential to sustain mating projection growth in budding yeast (Saccharomyces cerevisiae). Our theoretical results indicate that the mechanical feedback provided by the Cell Wall Integrity pathway, with cell wall stress sensors Wsc1 and Mid2 increasingly activating membrane-localized cell wall synthases Fks1/2 upon faster cell wall expansion, stabilizes mating projection growth without affecting cell shape. Experimental perturbation of the osmotic pressure and cell wall mechanics, as well as compromising the mechanical feedback through genetic deletion of the stress sensors, leads to cellular phenotypes that support the theoretical predictions. Our results indicate that while the existence of mechanical feedback is essential to stabilize mating projection growth, the shape and size of the cell are insensitive to the feedback. PMID:29346368

  3. Changes in levels of cell wall constituents in wheat seedlings grown under continuous hypergravity conditions

    Science.gov (United States)

    Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

    Effects of continuous hypergravity stimuli on the amounts and composition of cell wall constituents were investigated in wheat shoots. Hypergravity (300 g) treatment for three days after germination increased the net amount of cell wall polysaccharides such as hemicellulose and cellulose, but reduced the shoot elongation. As a result, the amount of cell wall polysaccharides per unit length of shoot increased under hypergravity. The hemicellulose fraction contained polysaccharides in the middle and low molecular mass range (5 kDa-1 MDa) and increased in response to hypergravity. Also, the amounts of arabinose (Ara) and xylose (Xyl), the major sugar components of the hemicellulose fraction, increased under hypergravity conditions. In addition to wall polysaccharides, hypergravity increased the amounts of cell wall-bound phenolic acids, such as ferulic acid (FA) and diferulic acid (DFA). Furthermore, the activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) was enhanced under hypergravity conditions. These results suggest that continuous hypergravity stimulates the synthesis of cell wall constituents, especially hemicellulosic arabinoxylans and cell wall-bound FA and DFA in wheat shoots. The increased PAL activity may promote the formation of FA and DFA. These changes in cell wall architecture may be involved in making rigid and tough cell walls under hypergravity conditions and thereby contribute to the ability of plant to sustain their structures against gravitational stimuli.

  4. Cell wall integrity signaling in plants: "To grow or not to grow that's the question".

    Science.gov (United States)

    Voxeur, Aline; Höfte, Herman

    2016-09-01

    Plants, like yeast, have the ability to monitor alterations in the cell wall architecture that occur during normal growth or in changing environments and to trigger compensatory changes in the cell wall. We discuss how recent advances in our understanding of the cell wall architecture provide new insights into the role of cell wall integrity sensing in growth control. Next we review the properties of membrane receptor-like kinases that have roles in pH control, mechano-sensing and reactive oxygen species accumulation in growing cells and which may be the plant equivalents of the yeast cell wall integrity (CWI) sensors. Finally, we discuss recent findings showing an increasing role for CWI signaling in plant immunity and the adaptation to changes in the ionic environment of plant cells. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Cell wall dynamics modulate acetic acid-induced apoptotic cell death of Saccharomyces cerevisiae

    Science.gov (United States)

    Rego, António; Duarte, Ana M.; Azevedo, Flávio; Sousa, Maria J.; Côrte-Real, Manuela; Chaves, Susana R.

    2014-01-01

    Acetic acid triggers apoptotic cell death in Saccharomyces cerevisiae, similar to mammalian apoptosis. To uncover novel regulators of this process, we analyzed whether impairing MAPK signaling affected acetic acid-induced apoptosis and found the mating-pheromone response and, especially, the cell wall integrity pathways were the major mediators, especially the latter, which we characterized further. Screening downstream effectors of this pathway, namely targets of the transcription factor Rlm1p, highlighted decreased cell wall remodeling as particularly important for acetic acid resistance. Modulation of cell surface dynamics therefore emerges as a powerful strategy to increase acetic acid resistance, with potential application in industrial fermentations using yeast, and in biomedicine to exploit the higher sensitivity of colorectal carcinoma cells to apoptosis induced by acetate produced by intestinal propionibacteria. PMID:28357256

  6. Aberrant localization of lamin B receptor (LBR) in cellular senescence in human cells

    Energy Technology Data Exchange (ETDEWEB)

    Arai, Rumi; En, Atsuki; Ukekawa, Ryo [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Miki, Kensuke [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Ichiban Life Corporation, 1-1-7 Horai-cho, Naka-ku, Yokohama 231-0048 (Japan); Fujii, Michihiko, E-mail: mifuji@yokohama-cu.ac.jp [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Ayusawa, Dai [Graduate School of Nanobioscience, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027 (Japan); Ichiban Life Corporation, 1-1-7 Horai-cho, Naka-ku, Yokohama 231-0048 (Japan)

    2016-05-13

    5-Bromodeoxyuridine (BrdU), a thymidine analogue, induces cellular senescence in mammalian cells. BrdU induces cellular senescence probably through the regulation of chromatin because BrdU destabilizes or disrupts nucleosome positioning and decondenses heterochromatin. Since heterochromatin is tethered to the nuclear periphery through the interaction with the nuclear envelope proteins, we examined the localization of the several nuclear envelope proteins such as lamins, lamin-interacting proteins, nuclear pore complex proteins, and nuclear transport proteins in senescent cells. We have shown here that lamin B receptor (LBR) showed a change in localization in both BrdU-induced and replicative senescent cells.

  7. Novel Cell Wall Hydrolase CwlC from Bacillus thuringiensis Is Essential for Mother Cell Lysis.

    Science.gov (United States)

    Chen, Xiaomin; Gao, Tantan; Peng, Qi; Zhang, Jie; Chai, Yunrong; Song, Fuping

    2018-04-01

    In this study, a sporulation-specific gene (tentatively named cwlC ) involved in mother cell lysis in Bacillus thuringiensis was characterized. The encoded CwlC protein consists of an N-terminal N -acetylmuramoyl-l-alanine amidase (Mur N Ac-LAA) domain and a C-terminal amidase02 domain. The recombinant histidine-tagged CwlC proteins purified from Escherichia coli were able to directly bind to and digest the B. thuringiensis cell wall. The CwlC point mutations at the two conserved glutamic acid residues (Glu-24 and Glu-140) shown to be critical for the catalytic activity in homologous amidases resulted in a complete loss of cell wall lytic activity, suggesting that CwlC is an N -acetylmuramoyl-l-alanine amidase. Results of transcriptional analyses indicated that cwlC is transcribed as a monocistronic unit and that its expression is dependent on sporulation sigma factor K (σ K ). Deletion of cwlC completely blocked mother cell lysis during sporulation without impacting the sporulation frequency, Cry1Ac protein production, and insecticidal activity. Taken together, our data suggest that CwlC is an essential cell wall hydrolase for B. thuringiensis mother cell lysis during sporulation. Engineered B. thuringiensis strains targeting cwlC , which allows the crystal inclusion to remain encapsulated in the mother cell at the end of sporulation, may have the potential to become more effective biological control agents in agricultural applications since the crystal inclusion remains encapsulated in the mother cell at the end of sporulation. IMPORTANCE Mother cell lysis has been well studied in Bacillus subtilis , which involves three distinct yet functionally complementary cell wall hydrolases. In this study, a novel cell wall hydrolase, CwlC, was investigated and found to be essential for mother cell lysis in Bacillus thuringiensis CwlC of B. thuringiensis only shows 9 and 21% sequence identity with known B. subtilis mother cell hydrolases CwlB and CwlC, respectively

  8. Plasmacytoma with aberrant expression of myeloid markers, T-cell markers, and cytokeratin

    DEFF Research Database (Denmark)

    Shin, J S; Stopyra, G A; Warhol, M J

    2001-01-01

    Plasmacytomas are localized neoplastic proliferations of monoclonal plasma cells. When multifocal, the process is referred to as multiple myeloma. These lesions exhibit a pattern of antigen expression and cytomorphology that usually leads to a ready diagnosis. However, potentially troublesome var...

  9. An update on receptor-like kinase involvement in the maintenance of plant cell wall integrity.

    Science.gov (United States)

    Engelsdorf, Timo; Hamann, Thorsten

    2014-10-01

    Plant cell walls form the interface between the cells and their environment. They perform different functions, such as protecting cells from biotic and abiotic stress and providing structural support during development. Maintenance of the functional integrity of cell walls during these different processes is a prerequisite that enables the walls to perform their particular functions. The available evidence suggests that an integrity maintenance mechanism exists in plants that is capable of both detecting wall integrity impairment caused by cell wall damage and initiating compensatory responses to maintain functional integrity. The responses involve 1-aminocyclopropane-1-carboxylic acid (ACC), jasmonic acid, reactive oxygen species and calcium-based signal transduction cascades as well as the production of lignin and other cell wall components. Experimental evidence implicates clearly different signalling molecules, but knowledge regarding contributions of receptor-like kinases to this process is less clear. Different receptor-like kinase families have been considered as possible sensors for perception of cell wall damage; however, strong experimental evidence that provides insights into functioning exists for very few kinases. This review examines the involvement of cell wall integrity maintenance in different biological processes, defines what constitutes plant cell wall damage that impairs functional integrity, clarifies which stimulus perception and signal transduction mechanisms are required for integrity maintenance and assesses the available evidence regarding the functions of receptor-like kinases during cell wall integrity maintenance. The review concludes by discussing how the plant cell wall integrity maintenance mechanism could form an essential component of biotic stress responses and of plant development, functions that have not been fully recognized to date. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany

  10. Germ tube-specific antigens of Candida albicans cell walls

    International Nuclear Information System (INIS)

    Sundstrom, P.R.

    1986-01-01

    Studies were performed to characterize the surface differences between blastospores and germ tubes of the pathogenic, dimorphic yeast, Candida albicans, and to identify components of yeast cells responsible for these differences. Investigation of surfaces differences of the two growth forms was facilitated by the production of rabbit antiserum prepared against Formalin-treated yeast possessing germ tubes. To prepare antiserum specific for germ tubes, this serum was adsorbed with stationary phase blastospores. Whereas the unadsorbed antiserum reacted with both blastospore and germ tube forms by immunofluorescence and Enzyme-Linked Immunosorbent Assay, the adsorbed antiserum did not react with blastospores but detected germ tube-specific antigens in hyphal forms. The differences between blastospores and germ tubes of Candida albicans, were further studied by comparing enzymatic digests of cell walls of both growth forms in radiolabeled organisms. Organisms were labeled either on the surface with 125 I, or metabolically with [ 35 S] methionine or [ 3 H] mannose. Three-surface-located components (as shown by antibody adsorption and elution experiments) were precipitated from Zymolase digests. All three components were mannoproteins as shown by their ability to bind Concanavalin A, and to be labeled in protein labeling procedures, and two of these (200,000 and 155,000 molecular weight) were germ tube specific, as shown by their ability to be precipitated by germ tube-specific antiserum. Monoclonal antibodies were prepared to C. albicans, using blastospores bearing germ tubes as immunogen

  11. Cell wall proteins of Sporothrix schenckii as immunoprotective agents.

    Science.gov (United States)

    Alba-Fierro, Carlos A; Pérez-Torres, Armando; López-Romero, Everardo; Cuéllar-Cruz, Mayra; Ruiz-Baca, Estela

    2014-01-01

    Sporothrix schenckii is the etiological agent of sporotrichosis, an endemic subcutaneous mycosis in Latin America. Cell wall (CW) proteins located on the cell surface are inducers of cellular and humoral immune responses, potential candidates for diagnosis purposes and to generate vaccines to prevent fungal infections. This mini-review emphasizes the potential use of S. schenckii CW proteins as protective and therapeutic immune response inducers against sporotrichosis. A number of pathogenic fungi display CW components that have been characterized as inducers of protective cellular and humoral immune responses against the whole pathogen from which they were originally purified. The isolation and characterization of immunodominant protein components of the CW of S. schenckii have become relevant because of their potential in the development of protective and therapeutic immune responses against sporotrichosis. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012). Copyright © 2013 Revista Iberoamericana de Micología. Published by Elsevier Espana. All rights reserved.

  12. Feruloyl Oligosaccharides from Cell Walls of Suspension-Cultured Spinach Cells and Sugar Beet Pulp : STRUCTURE AND FUNCTION OF CELLS

    OpenAIRE

    Tadashi, ISHII; Forestry and Forest Products Research Institute

    1994-01-01

    Cell walls of suspension-cultured spinach cells and sugar beet pulp were separately hydrolyzed with Driselase. A feruloyl arabinobiose was isolated from both spinach cells and sugar beet. Four feruloyl oligosaccharides were obtained from sugar beet. The four oligosaccharides were characterized by NMR spectroscopy, methylation analysis and FAB-MS.

  13. A role for aberrantly expressed nuclear localized decorin in migration and invasion of dysplastic and malignant oral epithelial cells.

    Science.gov (United States)

    Dil, Nyla; Banerjee, Abhijit G

    2011-09-29

    Oral cancer is the sixth most common malignancy worldwide with a mortality rate that is higher than many other cancers. Death usually occurs as a result of local invasion and regional lymph node metastases. Decorin is a multifunctional proteoglycan of the extracellular matrix that affects the biology of various types of cancer. Previously; we have shown that decorin is aberrantly expressed in the nucleus in human dysplastic oral keratinocytes (DOK) and malignant squamous cells carcinoma (SCC-25) and human biopsy tissues. In this study, we examined the role of nuclear decorin in oral cancer progression. We have used a post-transcriptional gene silencing (RNA interference) approach to stably knockdown nuclear decorin gene expression in DOK and SCC-25 cells using a specific shRNA plasmid and a combination of immunological and molecular techniques to study nuclear decorin function in these oral epithelial cell lines. More than 80% decorin silencing/knockdown was achieved as confirmed by real time PCR and western blot analysis in both DOK and SCC-25 cells. This RNA interference-mediated knockdown of nuclear decorin expression resulted in significantly reduced invasion and migration in these cell lines as measured by Matrigel™ coated and uncoated Trans well chamber assays respectively. Decorin silencing also resulted in reduced IL-8 mRNA and proteins levels in these cell lines. Culturing decorin silenced DOK and SCC-25 cells, with recombinant human IL-8 or IL-8 containing conditioned medium from respective un-transfected cells for 24 h prior to migration and invasion experiments, resulted in the salvation of reduced migration and invasion phenotype. Furthermore, we found that nuclear localized decorin interacts with EGFR in the nuclear fractions of both DOK and SCC-25 cells. Interestingly, EGFR (trans) activation has previously been shown to be involved in IL-8 production in various epithelia. Taken together, our results indicate that nuclear localized decorin plays an

  14. Cadmium-induced malignant transformation in rat liver cells: role of aberrant oncogene expression and minimal role of oxidative stress.

    Science.gov (United States)

    Qu, Wei; Diwan, Bhalchandra A; Reece, Jeffrey M; Bortner, Carl D; Pi, Jingbo; Liu, Jie; Waalkes, Michael P

    2005-04-10

    Our study examined the role of oxidative stress and aberrant gene expression in malignant transformation induced by chronic, low-level cadmium exposure in non-tumorigenic rat liver epithelial cell line, TRL 1215. Cells were cultured in 1.0 microM cadmium (as CdCl(2)) for up to 28 weeks and compared to passage-matched control cells. The level of cadmium used for transformation produced no evidence of increased superoxide (O(2) (-*.)) or hydrogen peroxide (H(2)O(2)) levels in the early stages of exposure (cadmium exposed liver epithelial cells (CCE-LE) were hyperproliferative with a growth rate about 3-fold higher than control cells. CCE-LE cells produced highly aggressive tumors upon inoculation into mice confirming malignant transformation. Analysis of cellular reactive oxygen species (ROS) showed that CCE-LE cells possessed markedly lower basal levels of intracellular O(2) (-*.)and H(2)O(2) and were very tolerant to high-dose (50 microM) cadmium-induced ROS. Time course studies showed the production of ROS by high-dose cadmium was abolished well in advance of malignant transformation. In contrast, marked overexpression of the oncogenes c-myc and c-jun occurred in transformed CCE-LE cells as evidenced by up to 10-fold increases in both transcript and protein. A significant increase in DNA-binding activity of the transcription factors AP-1 and NF-kappaB occurred in CCE-LE cells. Increases in oncogene expression and transcription factor activity occurred concurrently with malignant transformation. Thus, cadmium-induced ROS occurs as an early, high-dose event but is abolished well in advance of malignant transformation. Low-level chronic cadmium triggers oncogene overexpression possibly by altering critical transcription factor activity. Such changes in cellular gene expression likely culminate in the loss of growth control and cadmium-induced neoplastic transformation in CCE-LE cells, whereas generation of ROS by cadmium seemed to play a minimal role in this

  15. Cell wall mechanics and growth control in plants: the role of pectins revisited

    Directory of Open Access Journals (Sweden)

    Herman eHöfte

    2012-06-01

    Full Text Available How is the extensibility of growing plant cell walls regulated ? In the past, most studies have focused on the role of the cellulose/xyloglucan network and the enigmatic wall-loosening agents expansins. Here we review first how in the closest relatives of the land plants, the Charophycean algae, cell wall synthesis is coupled to cell wall extensibility by a chemical Ca2+-exchange mechanism between Ca2+-pectate complexes. We next discuss evidence for the existence in terrestrial plants of a similar primitive Ca2+-pectate-based growth control mechanism in parallel to the more recent, land plant-specific, expansin-dependent process.

  16. Cell wall as a target for bacteria inactivation by pulsed electric fields

    Science.gov (United States)

    Pillet, Flavien; Formosa-Dague, Cécile; Baaziz, Houda; Dague, Etienne; Rols, Marie-Pierre

    2016-01-01

    The integrity and morphology of bacteria is sustained by the cell wall, the target of the main microbial inactivation processes. One promising approach to inactivation is based on the use of pulsed electric fields (PEF). The current dogma is that irreversible cell membrane electro-permeabilisation causes the death of the bacteria. However, the actual effect on the cell-wall architecture has been poorly explored. Here we combine atomic force microscopy and electron microscopy to study the cell-wall organization of living Bacillus pumilus bacteria at the nanoscale. For vegetative bacteria, exposure to PEF led to structural disorganization correlated with morphological and mechanical alterations of the cell wall. For spores, PEF exposure led to the partial destruction of coat protein nanostructures, associated with internal alterations of cortex and core. Our findings reveal for the first time that the cell wall and coat architecture are directly involved in the electro-eradication of bacteria. PMID:26830154

  17. Pectic homogalacturonan masks abundant sets of xyloglucan epitopes in plant cell walls

    Directory of Open Access Journals (Sweden)

    Pedersen Henriette L

    2008-05-01

    Full Text Available Abstract Background Molecular probes are required to detect cell wall polymers in-situ to aid understanding of their cell biology and several studies have shown that cell wall epitopes have restricted occurrences across sections of plant organs indicating that cell wall structure is highly developmentally regulated. Xyloglucan is the major hemicellulose or cross-linking glycan of the primary cell walls of dicotyledons although little is known of its occurrence or functions in relation to cell development and cell wall microstructure. Results Using a neoglycoprotein approach, in which a XXXG heptasaccharide of tamarind seed xyloglucan was coupled to BSA to produce an immunogen, we have generated a rat monoclonal antibody (designated LM15 to the XXXG structural motif of xyloglucans. The specificity of LM15 has been confirmed by the analysis of LM15 binding using glycan microarrays and oligosaccharide hapten inhibition of binding studies. The use of LM15 for the analysis of xyloglucan in the cell walls of tamarind and nasturtium seeds, in which xyloglucan occurs as a storage polysaccharide, indicated that the LM15 xyloglucan epitope occurs throughout the thickened cell walls of the tamarind seed and in the outer regions, adjacent to middle lamellae, of the thickened cell walls of the nasturtium seed. Immunofluorescence analysis of LM15 binding to sections of tobacco and pea stem internodes indicated that the xyloglucan epitope was restricted to a few cell types in these organs. Enzymatic removal of pectic homogalacturonan from equivalent sections resulted in the abundant detection of distinct patterns of the LM15 xyloglucan epitope across these organs and a diversity of occurrences in relation to the cell wall microstructure of a range of cell types. Conclusion These observations support ideas that xyloglucan is associated with pectin in plant cell walls. They also indicate that documented patterns of cell wall epitopes in relation to cell

  18. Process and device for controling lateral wall of fuel assembly storage cell

    International Nuclear Information System (INIS)

    Moreau, B.

    1989-01-01

    The inspection procedure involves moving a detection system along the length of the wall of a cell in the fuel storage rack immersed in water. The detection system has at least one probe for determining the wall thickness. The probe signal is received above the pond and compared against a reference signal. This process allows to verify the presence of neutron absorbing material in the side walls of the cell [fr

  19. Painting analysis of chromosome aberrations induced by energetic heavy ions in human cells

    Science.gov (United States)

    Wu, H.; Hada, M.; Cucinotta, F. A.

    Energetic heavy ions pose a great health risk to astronauts in extended ISS and future exploration missions High-LET heavy ions are particularly effective in causing various biological effects including cell inactivation genetic mutations and cancer induction Most of these biological endpoints are closely related to chromosomal damage which can be utilized as a biomarker for radiation insults Over the years we have studied chromosomal damage in human fibroblast epithelia and lymphocyte cells exposed in vitro to energetic charged particles generated at several accelerator facilities in the world Various fluorescence in situ hybridization painting techniques have been used to identify from only the telomere region of the chromosome to every chromosome in a human cell We will summarize the results of the investigations and discuss the unique radiation signatures and biomarkers for space radiation exposure

  20. Immuno and affinity cytochemical analysis of cell wall composition in the moss Physcomitrella patens

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Berry

    2016-03-01

    Full Text Available In contrast to homeohydric vascular plants, mosses employ a poikilohydric strategy for surviving in the dry aerial environment. A detailed understanding of the structure, composition, and development of moss cell walls can contribute to our understanding of not only the evolution of overall cell wall complexity, but also the differences that have evolved in response to selection for different survival strategies. The model moss species Physcomitrella patens has a predominantly haploid lifecycle consisting of protonemal filaments that regenerate from protoplasts and enlarge by tip growth, and leafy gametophores composed of cells that enlarge by diffuse growth and differentiate into several different types. Advantages for genetic studies include methods for efficient targeted gene modification and extensive genomic resources. Immuno and affinity cytochemical labeling were used to examine the distribution of polysaccharides and proteins in regenerated protoplasts, protonemal filaments, rhizoids, and sectioned gametophores of P. patens. The cell wall composition of regenerated protoplasts was also characterized by flow cytometry. Crystalline cellulose was abundant in the cell walls of regenerating protoplasts and protonemal cells that developed on media of high osmolarity, whereas homogalacturonan was detected in the walls of protonemal cells that developed on low osmolarity media and not in regenerating protoplasts. Mannan was the major hemicellulose detected in all tissues tested. Arabinogalactan proteins were detected in different cell types by different probes, consistent with structural heterogeneity. The results reveal developmental and cell type specific differences in cell wall composition and provide a basis for analyzing cell wall phenotypes in knockout mutants.

  1. Arabidopsis seed coat mucilage is a specialized cell wall that can be used as a model for genetic analysis of plant cell wall structure and function

    Directory of Open Access Journals (Sweden)

    George Wentzel Haughn

    2012-04-01

    Full Text Available Arabidopsis seed coat epidermal cells produce a large quantity of mucilage that is extruded upon exposure to water. Chemical analyses and cell biological techniques suggest that this mucilage represents a specialized type of secondary cell wall composed primarily of pectin with lesser amounts of cellulose and xyloglucan. Once extruded, the mucilage capsule has a distinctive structure with an outer non-adherent layer that is easily removed by shaking in water, and an inner adherent layer that can only be removed with strong acid or base. Most of the cellulose in the mucilage is present in the inner layer and is responsible at least in part for its adherence to the seed. There are also differences in the pectin composition between the two layers that could contribute to the difference in adherence. The Arabidopsis seed coat epidermis and its mucilage are not essential for seed viability or germination. This dispensability, combined with the fact that the epidermal cells synthesize an accessible pectin-rich cell wall at a specific time in development, makes them well suited as a genetic model for studying cell wall biogenesis, function and regulation. Mutants defective in seed mucilage identified by both forward and reverse genetic analyses are proving useful in establishing connections between carbohydrate structure and cell wall properties in vivo. In the future, genetic engineering of seed coat mucilage carbohydrates should prove useful for testing hypotheses concerning cell wall structure and function.

  2. Arabidopsis Seed Coat Mucilage is a Specialized Cell Wall that Can be Used as a Model for Genetic Analysis of Plant Cell Wall Structure and Function.

    Science.gov (United States)

    Haughn, George W; Western, Tamara L

    2012-01-01

    Arabidopsis seed coat epidermal cells produce a large quantity of mucilage that is extruded upon exposure to water. Chemical analyses and cell biological techniques suggest that this mucilage represents a specialized type of secondary cell wall composed primarily of pectin with lesser amounts of cellulose and xyloglucan. Once extruded, the mucilage capsule has a distinctive structure with an outer non-adherent layer that is easily removed by shaking in water, and an inner adherent layer that can only be removed with strong acid or base. Most of the cellulose in the mucilage is present in the inner layer and is responsible at least in part for its adherence to the seed. There are also differences in the pectin composition between the two layers that could contribute to the difference in adherence. The Arabidopsis seed coat epidermis and its mucilage are not essential for seed viability or germination. This dispensability, combined with the fact that the epidermal cells synthesize an accessible pectin-rich cell wall at a specific time in development, makes them well suited as a genetic model for studying cell wall biogenesis, function, and regulation. Mutants defective in seed mucilage identified by both forward and reverse genetic analyses are proving useful in establishing connections between carbohydrate structure and cell wall properties in vivo. In the future, genetic engineering of seed coat mucilage carbohydrates should prove useful for testing hypotheses concerning cell wall structure and function.

  3. Autolysis of cell walls from polygalacturonase-antisense tomato fruit in simulated apoplastic solutions.

    Science.gov (United States)

    Almeida, Domingos P F; Huber, Donald J

    2011-06-01

    Autolysis of cell walls from polygalacturonase (PG)-antisense tomato fruit was studied in a conventional buffer designed to maximize the catalytic activity of PG (30 mM sodium acetate, 150 mM NaCl, pH 4.5), and in solutions mimicking the pH and mineral composition of the fruit apoplast at the mature-green and ripe stages. Autolytic release of uronic acids was very limited under simulated apoplastic conditions compared with the conventional buffer, but minimal differences in the release of reducing groups were observed among the incubation conditions. Autolytic release of uronic acids from active walls was lower than solubilization from enzymically inactive walls. Uronic acids that remained ionically bound to the cell walls during autolysis were subsequently extracted and analyzed by size exclusion chromatography. The elution profiles of ionically bound uronic acids from cell walls incubated under optimal conditions were similar for all ripening stages. In solutions mimicking the pH and mineral composition of the apoplast of mature-green and ripe fruit, uronic acids extracted from pink and ripe fruit cell walls showed a decrease in average molecular mass compared with polymers from mature-green cell walls. The results suggest that the composition of the incubation solution exert strong influence on PG-independent cell wall autolysis and that enzymically active walls restrain PG-independent pectin solubilization. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  4. The role of the hemicelluloses in the nanobiology of wood cell walls : a systems theoretic perspective

    Science.gov (United States)

    Rajai H. Atalla

    2005-01-01

    The hemicelluloses have not received adequate attention in studies of wood cell walls because the complexity of their structures does not admit easy interpretation within the paradigms of polymer science. Two-phase composite models of the cell wall have led many to view their primary function as one of coupling cellulose and lignin to enhance the mechanical properties...

  5. Multi-scale visualization and characterization of lignocellulosic plant cell wall deconstruction during thermochemical pretreatment

    Science.gov (United States)

    Shishir P. S. Chundawat; Bryon S. Donohoe; Leonardo da Costa Sousa; Thomas Elder; Umesh P. Agarwal; Fachuang Lu; John Ralph; Michael E. Himmel; Venkatesh Balan; Bruce E. Dale

    2011-01-01

    Deconstruction of lignocellulosic plant cell walls to fermentable sugars by thermochemical and/or biological means is impeded by several poorly understood ultrastructural and chemical barriers. A promising thermochemical pretreatment called ammonia fiber expansion (AFEX) overcomes the native recalcitrance of cell walls through subtle morphological and physicochemical...

  6. A synthetic glycan microarray enables epitope mapping of plant cell wall glycan-directed antibodies

    DEFF Research Database (Denmark)

    Ruprecht, Colin; Bartetzko, Max P; Senf, Deborah

    2017-01-01

    In the last three decades, more than 200 monoclonal antibodies have been raised against most classes of plant cell wall polysaccharides by different laboratories world-wide. These antibodies are widely used to identify differences in plant cell wall components in mutants, organ and tissue types, ...

  7. CONSTITUTIVE MELANIN IN THE CELL WALL OF THE ETIOLOGIC AGENT OF LOBO'S DISEASE

    Directory of Open Access Journals (Sweden)

    TABORDA Valeria B.A.

    1999-01-01

    Full Text Available Lobo's disease is a chronic granulomatous disease caused by the obligate pathogenic fungus, whose cell walls contain constitutive melanin. In contrast, melanin does not occur in the cell walls of Paracoccidioides brasiliensis when stained by the Fontana-Masson stain.

  8. Distinct cell wall architectures in seed endosperms in representatives of the Brassicaceae and Solanaceae.

    Science.gov (United States)

    Lee, Kieran J D; Dekkers, Bas J W; Steinbrecher, Tina; Walsh, Cherie T; Bacic, Antony; Bentsink, Leónie; Leubner-Metzger, Gerhard; Knox, J Paul

    2012-11-01

    In some species, a crucial role has been demonstrated for the seed endosperm during germination. The endosperm has been shown to integrate environmental cues with hormonal networks that underpin dormancy and seed germination, a process that involves the action of cell wall remodeling enzymes (CWREs). Here, we examine the cell wall architectures of the endosperms of two related Brassicaceae, Arabidopsis (Arabidopsis thaliana) and the close relative Lepidium (Lepidium sativum), and that of the Solanaceous species, tobacco (Nicotiana tabacum). The Brassicaceae species have a similar cell wall architecture that is rich in pectic homogalacturonan, arabinan, and xyloglucan. Distinctive features of the tobacco endosperm that are absent in the Brassicaceae representatives are major tissue asymmetries in cell wall structural components that reflect the future site of radicle emergence and abundant heteromannan. Cell wall architecture of the micropylar endosperm of tobacco seeds has structural components similar to those seen in Arabidopsis and Lepidium endosperms. In situ and biomechanical analyses were used to study changes in endosperms during seed germination and suggest a role for mannan degradation in tobacco. In the case of the Brassicaceae representatives, the structurally homogeneous cell walls of the endosperm can be acted on by spatially regulated CWRE expression. Genetic manipulations of cell wall components present in the Arabidopsis seed endosperm demonstrate the impact of cell wall architectural changes on germination kinetics.

  9. Cell wall proteomics contributes to explore the functional proteins of Brachypodium distachyon grains.

    Science.gov (United States)

    Fang, Xianping; Chen, Wenyue; Ma, Huasheng

    2015-07-01

    The plant cell wall is the first barrier in response to external stimuli and cell wall proteins (CWPs) can play an important role in the modulation of plant growth and development. In the past 10 years, the plant cell wall proteomics has increasingly become a very active research filed, which provides a broader understanding of CWPs for people. The cell wall proteome of Arabidopsis, rice, and other model plants has begun to take shape, and proteomic technology has become an effective way to identify the candidate functional CWPs in large scale. The challenging work of Francin-Allami et al. (Proteomics 2015, 15, 2296-2306) is a vital step toward building the most extensive cell wall proteome of a monocot species. They identified 299 cell wall proteins in Brachypodium distachyon grains, and also compared the grain cell wall proteome with those of B. distachyon culms and leaves, which provides a new perspective for further explaining the plant cell wall structures and remodeling mechanism. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. In Vivo Cell Wall Loosening by Hydroxyl Radicals during Cress Seed Germination and Elongation Growth

    NARCIS (Netherlands)

    Muller, K.; Linkies, A.; Vreeburg, R.A.M.; Fry, S.C.; Krieger-Liszkay, A.; Leubner-Metzger, G.

    2009-01-01

    Loosening of cell walls is an important developmental process in key stages of the plant life cycle, including seed germination, elongation growth, and fruit ripening. Here, we report direct in vivo evidence for hydroxyl radical (·OH)-mediated cell wall loosening during plant seed germination and

  11. Fermentation characteristics of polysaccharide fractions extracted from the cell walls of soya bean cotyledons

    NARCIS (Netherlands)

    Laar, van H.; Tamminga, S.; Williams, B.A.; Verstegen, M.W.A.; Schols, H.A.

    2000-01-01

    Full-fat soya beans were separated into hulls and cotyledons. After separation the cell wall fraction was extracted from the cotyledons. These purified cell walls were sequentially extracted with 0.05 M cyclohexane-trans-1,2-diamine-N,N,N ,N -tetraacetate (CDTA) 0.05 M NH4 oxalate (extract 1), 0.05

  12. Understanding pollen tube growth: the hydrodynamic model versus the cell wall model

    NARCIS (Netherlands)

    Zonia, L.; Munnik, T.

    2011-01-01

    Scientific progress stimulates the evolution of models used to understand and conceptualize biological behaviors. The widely accepted cell wall model of pollen tube growth explains stochastic growth of the apical pectin wall, but fails to explain the mechanism driving oscillations in growth and cell

  13. Thioridazine affects transcription of genes involved in cell wall biosynthesis in methicillin-resistant Staphylococcus aureus

    DEFF Research Database (Denmark)

    Bonde, Mette; Højland, Dorte Heidi; Kolmos, Hans Jørn

    2011-01-01

    have previously shown that the expression of some resistance genes is abolished after treatment with thioridazine and oxacillin. To further understand the mechanism underlying the reversal of resistance, we tested the expression of genes involved in antibiotic resistance and cell wall biosynthesis...... reversal of resistance by thioridazine relies on decreased expression of specific genes involved in cell wall biosynthesis....

  14. On the robustness of the geometrical model for cell wall deposition

    NARCIS (Netherlands)

    Diotallevi, F.; Mulder, B.M.; Grasman, J.

    2010-01-01

    All plant cells are provided with the necessary rigidity to withstand the turgor by an exterior cell wall. This wall is composed of long crystalline cellulose microfibrils embedded in a matrix of other polysaccharides. The cellulose microfibrils are deposited by mobile membrane bound protein

  15. Aberrant mesenchymal differentiation of glioma stem-like cells : Implications for therapeutic targeting

    NARCIS (Netherlands)

    Balasubramaniyan, Veerakumar; Vaillant, Brian; Wang, Shuzhen; Gumin, Joy; Butalid, M. Elena; Sai, Ke; Mukheef, Farah; Kim, Se Hoon; Boddeke, H. W. G. M.; Lang, Frederick; Aldape, Kenneth; Sulman, Erik P.; Bhat, Krishna P.; Colman, Howard

    2015-01-01

    Differentiation has been proposed as a therapeutic strategy for glioblastoma (GBM) in part due to observations of stem-like cells in GBM that have been shown to undergo terminal differentiation in response to growth factor withdrawal and BMP activation. However, the effects of long term exposure to

  16. Effects of gemcitabine on cell survival and chromosome aberrations after pulsed low dose-rate irradiation

    NARCIS (Netherlands)

    Castro Kreder, Natasja; van Bree, Chris; Franken, Nicolaas A. P.; Haveman, Jaap

    2004-01-01

    The radiosensitizing potential of gemcitabine (2',2'-difluoro-2'-deoxycytidine) was studied in combination with pulsed low dose-rate irradiation. The experiments were carried out with a human lung carcinoma cell line SW 1573. These were irradiated at pulsed low dose rate (p-LDR); the average dose

  17. Development and applications of advanced probing tools for cell wall biology

    DEFF Research Database (Denmark)

    Hansen, Aleksander Riise

    Common to all plant species, the cell wall is the fiber rich tough outer coat that protects the plant cell. This study set out to expand the set of probes against glycans found primarily in the plant cell wall, and explore their application for use in related agroindustrial and fundamental research...... the function of pectin methyl esterase inhibitors and their role in plant defense against microbial degradation, and cell wall structural dynamics in relation to cell detachment from roots. The second part describes phage display as a method for developing probes against targets that are poor immunogens...

  18. Pectate chemistry links cell expansion to wall deposition in Chara corallina.

    Science.gov (United States)

    Proseus, Timothy E; Boyer, John S

    2012-11-01

    Pectate (polygalacturonic acid) acts as a chelator to bind calcium and form cross-links that hold adjacent pectate polymers and thus plant cell walls together. When under tension from turgor pressure in the cell, the cross-links appear to distort and weaken. New pectate supplied by the cytoplasm is undistorted and removes wall calcium preferentially from the weakened bonds, loosening the wall and accelerating cell expansion. The new pectate now containing the removed calcium can bind to the wall, strengthening it and linking expansion to wall deposition. But new calcium needs to be added as well to replenish the calcium lost from the vacated wall pectate.  A recent report demonstrated that growth was disrupted if new calcium was unavailable.  The present addendum highlights this conclusion by reviewing an experiment from before the chelation chemistry was understood. Using cell wall labeling, a direct link appeared between wall expansion and wall deposition. Together, these experiments support the concept that newly supplied pectate has growth activity on its way to deposition in the wall. Growth rate is thus controlled by signals affecting the rate of pectate release. After release, the coordination of expansion and deposition arises naturally from chelation chemistry when polymers are under tension from turgor pressure. 

  19. The Endocrine Dyscrasia that Accompanies Menopause and Andropause Induces Aberrant Cell Cycle Signaling that Triggers Cell Cycle Reentry of Post-mitotic Neurons, Neurodysfunction, Neurodegeneration and Cognitive Disease

    Science.gov (United States)

    Atwood, Craig S.; Bowen, Richard L.

    2016-01-01

    Sex hormones are the physiological factors that regulate neurogenesis during embryogenesis and continuing through adulthood. These hormones support the formation of brain structures such as dendritic spines, axons and synapses required for the capture of information (memories). Intriguingly, a recent animal study has demonstrated that induction of neurogenesis results in the loss of previously encoded memories in animals (e.g. infantile amnesia). In this connection, much evidence now indicates that Alzheimer’s disease (AD) also involves aberrant re-entry of post-mitotic neurons into the cell cycle. Cell cycle abnormalities appear very early in the disease, prior to the appearance of plaques and tangles, and explain the biochemical, neuropathological and cognitive changes observed with disease progression. Since sex hormones control when and how neurons proliferate and differentiate, the endocrine dyscrasia that accompanies menopause and andropause is a key signaling event that impacts neurogenesis and the acquisition, processing, storage and recall of memories. Here we review the biochemical, epidemiological and clinical evidence that alterations in endocrine signaling with menopause and andropause drive the aberrant re-entry of post-mitotic neurons into an abortive cell cycle with neurite retraction that leads to neuron dysfunction and death. When the reproductive axis is in balance, luteinizing hormone (LH), and its fetal homolog, human chorionic gonadotropin (hCG), promote pluripotent human and totipotent murine embryonic stem cell and neuron proliferation. However, strong evidence supports menopausal/andropausal elevations in the ratio of LH:sex steroids as driving aberrant mitotic events mediated by the upregulation of tumor necrosis factor, amyloid-β precursor protein processing towards the production of mitogenic Aβ, and the activation of Cdk5, a key regulator of cell cycle progression and tau phosphorylation (a cardinal feature of both neurogenesis and

  20. Immunological approaches to plant cell wall and biomass characterization: Glycome Profiling.

    Science.gov (United States)

    Pattathil, Sivakumar; Avci, Utku; Miller, Jeffrey S; Hahn, Michael G

    2012-01-01

    The native complexity of plant cell walls makes research on them challenging. Hence, it is advantageous to have a diversity of tools that can be used to analyze and characterize plant cell walls. In this chapter, we describe one of two immunological approaches that can be employed for screening of plant cell wall/biomass materials from diverse plants and tissues. This approach, Glycome Profiling, lends itself well to moderate to high-throughput screening of plant cell wall/biomass samples. Glycome Profiling is being further optimized to reduce the amount of sample required for the analysis, and to improve the sensitivity and throughput of the assay. We are optimistic that Glycome Profiling will prove to be a broadly applicable experimental approach that will find increasing application to a wide variety of studies on plant cell wall/biomass samples.

  1. Variability of cell wall polysaccharides composition and hemicellulose enzymatic profile in an apple progeny.

    Science.gov (United States)

    Galvez-Lopez, D; Laurens, F; Quéméner, B; Lahaye, M

    2011-12-01

    The genetic variability of apple cell walls polysaccharides chemical composition and structure was assessed in a progeny of 141 individuals harvested over 2 years. The variability of the hemicelluloses oligosaccharides released by glucanase was analyzed by MALDI-TOF MS. The genetic contribution was distinguished from harvest year as well as from parental crossing patterns and scab resistance selection. Results showed that harvest year had a major impact on cell wall polysaccharide composition and structure. Within each harvest, genetic effect impact more significantly cell wall polysaccharide chemistry than does reciprocal crossing or early scab selection. Uronic acids, glucose, galactose and xylose contents as well as some glucomannan and xyloglucan structures have a high heritability. This first cell wall chemotyping of an apple progeny opens the way for future searches of genetic markers for the chemical variability of cell wall polysaccharides. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. β-(1,3)-Glucan Unmasking in Some Candida albicans Mutants Correlates with Increases in Cell Wall Surface Roughness and Decreases in Cell Wall Elasticity.

    Science.gov (United States)

    Hasim, Sahar; Allison, David P; Retterer, Scott T; Hopke, Alex; Wheeler, Robert T; Doktycz, Mitchel J; Reynolds, Todd B

    2017-01-01

    Candida albicans is among the most common human fungal pathogens, causing a broad range of infections, including life-threatening systemic infections. The cell wall of C. albicans is the interface between the fungus and the innate immune system. The cell wall is composed of an outer layer enriched in mannosylated glycoproteins (mannan) and an inner layer enriched in β-(1,3)-glucan and chitin. Detection of C. albicans by Dectin-1, a C-type signaling lectin specific for β-(1,3)-glucan, is important for the innate immune system to recognize systemic fungal infections. Increased exposure of β-(1,3)-glucan to the immune system occurs when the mannan layer is altered or removed in a process called unmasking. Nanoscale changes to the cell wall during unmasking were explored in live cells with atomic force microscopy (AFM). Two mutants, the cho1Δ/Δ and kre5Δ/Δ mutants, were selected as representatives that exhibit modest and strong unmasking, respectively. Comparisons of the cho1Δ/Δ and kre5Δ/Δ mutants to the wild type reveal morphological changes in their cell walls that correlate with decreases in cell wall elasticity. In addition, AFM tips functionalized with Dectin-1 revealed that the forces of binding of Dectin-1 to all of the strains were similar, but the frequency of binding was highest for the kre5Δ/Δ mutant, decreased for the cho1Δ/Δ mutant, and rare for the wild type. These data show that nanoscale changes in surface topology are correlated with increased Dectin-1 adhesion and decreased cell wall elasticity. AFM, using tips functionalized with immunologically relevant molecules, can map epitopes of the cell wall and increase our understanding of pathogen recognition by the immune system. Copyright © 2016 American Society for Microbiology.

  3. Breakdown of cell wall nanostructure in dilute acid pretreated biomass.

    Science.gov (United States)

    Pingali, Sai Venkatesh; Urban, Volker S; Heller, William T; McGaughey, Joseph; O'Neill, Hugh; Foston, Marcus; Myles, Dean A; Ragauskas, Arthur; Evans, Barbara R

    2010-09-13

    The generation of bioethanol from lignocellulosic biomass holds great promise for renewable and clean energy production. A better understanding of the complex mechanisms of lignocellulose breakdown during various pretreatment methods is needed to realize this potential in a cost and energy efficient way. Here we use small-angle neutron scattering (SANS) to characterize morphological changes in switchgrass lignocellulose across molecular to submicrometer length scales resulting from the industrially relevant dilute acid pretreatment method. Our results demonstrate that dilute acid pretreatment increases the cross-sectional radius of the crystalline cellulose fibril. This change is accompanied by removal of hemicellulose and the formation of R(g) ∼ 135 A lignin aggregates. The structural signature of smooth cell wall surfaces is observed at length scales larger than 1000 A, and it remains remarkably invariable during pretreatment. This study elucidates the interplay of the different biomolecular components in the breakdown process of switchgrass by dilute acid pretreatment. The results are important for the development of efficient strategies of biomass to biofuel conversion.

  4. Modifications of Saccharomyces pastorianus cell wall polysaccharides with brewing process.

    Science.gov (United States)

    Bastos, Rita; Coelho, Elisabete; Coimbra, Manuel A

    2015-06-25

    The cell wall polysaccharides of brewers spent yeast Saccharomyces pastorianus (BSY) and the inoculum yeast (IY) were studied in order to understand the changes induced by the brewing process. The hot water and alkali extractions performed solubilized mainly mannoproteins, more branched for BSY than those of IY. Also, (31)P solid state NMR showed that the BSY mannoproteins were 3 times more phosphorylated. By electron microscopy it was observed that the final residues of alkali sequential extraction until 4M KOH preserved the yeast three-dimensional structure. The final residues, composed mainly by glucans (92%), showed that the BSY, when compared with IY, contained higher amount of (1→4)-linked Glc (43% for BSY and 16% for IY) and lower (1→3)-linked Glc (17% for BSY and 42% for IY). The enzymatic treatment of final residue showed that both BSY and IY had (α1→4)-linked Glc and (β1→4)-linked Glc, in a 2:1 ratio, showing that S. pastorianus increases their cellulose-like linkages with the brewing process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. β-1,3-Glucans are components of brown seaweed (Phaeophyceae) cell walls.

    Science.gov (United States)

    Raimundo, Sandra Cristina; Pattathil, Sivakumar; Eberhard, Stefan; Hahn, Michael G; Popper, Zoë A

    2017-03-01

    LAMP is a cell wall-directed monoclonal antibody (mAb) that recognizes a β-(1,3)-glucan epitope. It has primarily been used in the immunolocalization of callose in vascular plant cell wall research. It was generated against a brown seaweed storage polysaccharide, laminarin, although it has not often been applied in algal research. We conducted in vitro (glycome profiling of cell wall extracts) and in situ (immunolabeling of sections) studies on the brown seaweeds Fucus vesiculosus (Fucales) and Laminaria digitata (Laminariales). Although glycome profiling did not give a positive signal with the LAMP mAb, this antibody clearly detected the presence of the β-(1,3)-glucan in situ, showing that this epitope is a constituent of these brown algal cell walls. In F. vesiculosus, the β-(1,3)-glucan epitope was present throughout the cell walls in all thallus parts; in L. digitata, the epitope was restricted to the sieve plates of the conductive elements. The sieve plate walls also stained with aniline blue, a fluorochrome used as a probe for callose. Enzymatic digestion with an endo-β-(1,3)-glucanase removed the ability of the LAMP mAb to label the cell walls. Thus, β-(1,3)-glucans are structural polysaccharides of F. vesiculosus cell walls and are integral components of the sieve plates in these brown seaweeds, reminiscent of plant callose.

  6. Phyllanthus emblica Fruit Extract Activates Spindle Assembly Checkpoint, Prevents Mitotic Aberrations and Genomic Instability in Human Colon Epithelial NCM460 Cells

    Directory of Open Access Journals (Sweden)

    Xihan Guo

    2016-09-01

    Full Text Available The fruit of Phyllanthus emblica Linn. (PE has been widely consumed as a functional food and folk medicine in Southeast Asia due to its remarkable nutritional and pharmacological effects. Previous research showed PE delays mitotic progress and increases genomic instability (GIN in human colorectal cancer cells. This study aimed to investigate the similar effects of PE by the biomarkers related to spindle assembly checkpoint (SAC, mitotic aberrations and GIN in human NCM460 normal colon epithelial cells. Cells were treated with PE and harvested differently according to the biomarkers observed. Frequencies of micronuclei (MN, nucleoplasmic bridge (NPB and nuclear bud (NB in cytokinesis-block micronucleus assay were used as indicators of GIN. Mitotic aberrations were assessed by the biomarkers of chromosome misalignment, multipolar division, chromosome lagging and chromatin bridge. SAC activity was determined by anaphase-to- metaphase ratio (AMR and the expression of core SAC gene budding uninhibited by benzimidazoles related 1 (BubR1. Compared with the control, PE-treated cells showed (1 decreased incidences of MN, NPB and NB (p < 0.01; (2 decreased frequencies of all mitotic aberration biomarkers (p < 0.01; and (3 decreased AMR (p < 0.01 and increased BubR1 expression (p < 0.001. The results revealed PE has the potential to protect human normal colon epithelial cells from mitotic and genomic damages partially by enhancing the function of SAC.

  7. The cell wall-targeting antibiotic stimulon of Enterococcus faecalis.

    Directory of Open Access Journals (Sweden)

    Jacqueline Abranches

    Full Text Available Enterococcus faecalis is an opportunistic nosocomial pathogen that is highly resistant to a variety of environmental insults, including an intrinsic tolerance to antimicrobials that target the cell wall (CW. With the goal of determining the CW-stress stimulon of E. faecalis, the global transcriptional profile of E. faecalis OG1RF exposed to ampicillin, bacitracin, cephalotin or vancomycin was obtained via microarrays. Exposure to the β-lactams ampicillin and cephalotin resulted in the fewest transcriptional changes with 50 and 192 genes differentially expressed 60 min after treatment, respectively. On the other hand, treatment with bacitracin or vancomycin for 60 min affected the expression of, respectively, 377 and 297 genes. Despite the differences in the total number of genes affected, all antibiotics induced a very similar gene expression pattern with an overrepresentation of genes encoding hypothetical proteins, followed by genes encoding proteins associated with cell envelope metabolism as well as transport and binding proteins. In particular, all drug treatments, most notably bacitracin and vancomycin, resulted in an apparent metabolic downshift based on the repression of genes involved in translation, energy metabolism, transport and binding. Only 19 genes were up-regulated by all conditions at both the 30 and 60 min time points. Among those 19 genes, 4 genes encoding hypothetical proteins (EF0026, EF0797, EF1533 and EF3245 were inactivated and the respective mutant strains characterized in relation to antibiotic tolerance and virulence in the Galleria mellonella model. The phenotypes obtained for two of these mutants, ΔEF1533 and ΔEF3245, support further characterization of these genes as potential candidates for the development of novel preventive or therapeutic approaches.

  8. Turgor pressure moves polysaccharides into growing cell walls of Chara corallina.

    Science.gov (United States)

    Proseus, Timothy E; Boyer, John S

    2005-05-01

    Plant growth involves pressure-driven cell enlargement generally accompanied by deposition of new cell wall. New polysaccharides are secreted by the plasma membrane but their subsequent entry into the wall is obscure. Therefore, polysaccharides and gold colloids of various sizes were presented to the inner wall face as though they were secreted by the plasma membrane. Primary cell walls were isolated from growing internodes of Chara corallina and one end was attached to a glass capillary. Solutions of dextran or suspensions of gold colloids were pushed into the lumen by oil in the capillary. The oil did not enter the wall, and the solution or suspension was pressed against the inner wall face, pressurized at various 'artificial' P (turgor pressure), and polymer or colloid movement through the wall was monitored. Interstices in the wall matrix had a diameter of about 4.6 nm measured at high P with gold colloids. Small solute (0.8 nm) readily moved through these interstices unaffected by P. Dextrans of 3.5 nm diameter moved faster at higher P while dextran of 9 nm scarcely entered unless high P was present. Dextran of 11 nm did not enter unless P was above a threshold, and dextran of 27 nm did not enter at P as high as 0.5 MPa. The walls filtered the dextrans, which became concentrated against the inner wall face, and most polymer movement occurred after P stabilized and bulk flow ended. P created a steep gradient in concentration and mechanical force at the inner wall face that moved large polymers into small wall openings apparently by starting a polymer end or deforming the polymer mechanically at the inner wall face. This movement occurred at P generally accepted to extend the walls for growth.

  9. Comparison of RBE values of high- LET α-particles for the induction of DNA-DSBs, chromosome aberrations and cell reproductive death

    Directory of Open Access Journals (Sweden)

    Aten Jacob

    2011-06-01

    Full Text Available Abstract Background Various types of radiation effects in mammalian cells have been studied with the aim to predict the radiosensitivity of tumours and normal tissues, e.g. DNA double strand breaks (DSB, chromosome aberrations and cell reproductive inactivation. However, variation in correlations with clinical results has reduced general application. An additional type of information is required for the increasing application of high-LET radiation in cancer therapy: the Relative Biological Effectiveness (RBE for effects in tumours and normal tissues. Relevant information on RBE values might be derived from studies on cells in culture. Methods To evaluate relationships between DNA-DSB, chromosome aberrations and the clinically most relevant effect of cell reproductive death, for ionizing radiations of different LET, dose-effect relationships were determined for the induction of these effects in cultured SW-1573 cells irradiated with gamma-rays from a Cs-137 source or with α-particles from an Am-241 source. RBE values were derived for these effects. Ionizing radiation induced foci (IRIF of DNA repair related proteins, indicative of DSB, were assessed by counting gamma-H2AX foci. Chromosome aberration frequencies were determined by scoring fragments and translocations using premature chromosome condensation. Cell survival was measured by colony formation assay. Analysis of dose-effect relations was based on the linear-quadratic model. Results Our results show that, although both investigated radiation types induce similar numbers of IRIF per absorbed dose, only a small fraction of the DSB induced by the low-LET gamma-rays result in chromosome rearrangements and cell reproductive death, while this fraction is considerably enhanced for the high-LET alpha-radiation. Calculated RBE values derived for the linear components of dose-effect relations for gamma-H2AX foci, cell reproductive death, chromosome fragments and colour junctions are 1.0 ± 0.3, 14

  10. Glycosylation of Candida albicans cell wall proteins is critical for induction of innate immune responses and apoptosis of epithelial cells.

    Directory of Open Access Journals (Sweden)

    Jeanette Wagener

    Full Text Available C. albicans is one of the most common fungal pathogen of humans, causing local and superficial mucosal infections in immunocompromised individuals. Given that the key structure mediating host-C. albicans interactions is the fungal cell wall, we aimed to identify features of the cell wall inducing epithelial responses and be associated with fungal pathogenesis. We demonstrate here the importance of cell wall protein glycosylation in epithelial immune activation with a predominant role for the highly branched N-glycosylation residues. Moreover, these glycan moieties induce growth arrest and apoptosis of epithelial cells. Using an in vitro model of oral candidosis we demonstrate, that apoptosis induction by C. albicans wild-type occurs in early stage of infection and strongly depends on intact cell wall protein glycosylation. These novel findings demonstrate that glycosylation of the C. albicans cell wall proteins appears essential for modulation of epithelial immunity and apoptosis induction, both of which may promote fungal pathogenesis in vivo.

  11. Plasmacytoma with aberrant expression of myeloid markers, T-cell markers, and cytokeratin.

    Science.gov (United States)

    Shin, J S; Stopyra, G A; Warhol, M J; Multhaupt, H A

    2001-06-01

    Plasmacytomas are localized neoplastic proliferations of monoclonal plasma cells. When multifocal, the process is referred to as multiple myeloma. These lesions exhibit a pattern of antigen expression and cytomorphology that usually leads to a ready diagnosis. However, potentially troublesome variations in immunophenotype occur. We describe a case of a plasmacytoma from a patient who presented with sudden onset of pain and a lytic lesion of the left proximal humerus. Hematoxylin and eosin-stained sections showed a lymphoproliferative lesion composed of large lymphoid cells, some with plasmacytoid and immunoblastic features. The lesion also showed significant mitotic activity. Immunohistochemical staining was positive for CD45 (LCA), CD56 (N-CAM), CD43 (MT1), and cytokeratin CAM5.2. There was also clonal staining for lambda light chains. In addition, flow cytometric analysis showed positivity for myeloid markers such as CD13, CD33, CD38, and CD138. Significant negative markers include CD20 (L26), CD45RO (UCHL-1), and CD79alpha. The unusual phenotypic features of this plasmacytoma illustrate potential diagnostic pitfalls. It is important to fully study such lesions to correctly classify them, because this has significant impact on prognosis and management.

  12. Stomatal cell wall composition: distinctive structural patterns associated with different phylogenetic groups.

    Science.gov (United States)

    Shtein, Ilana; Shelef, Yaniv; Marom, Ziv; Zelinger, Einat; Schwartz, Amnon; Popper, Zoë A; Bar-On, Benny; Harpaz-Saad, Smadar

    2017-04-01

    Stomatal morphology and function have remained largely conserved throughout ∼400 million years of plant evolution. However, plant cell wall composition has evolved and changed. Here stomatal cell wall composition was investigated in different vascular plant groups in attempt to understand their possible effect on stomatal function. A renewed look at stomatal cell walls was attempted utilizing digitalized polar microscopy, confocal microscopy, histology and a numerical finite-elements simulation. The six species of vascular plants chosen for this study cover a broad structural, ecophysiological and evolutionary spectrum: ferns ( Asplenium nidus and Platycerium bifurcatum ) and angiosperms ( Arabidopsis thaliana and Commelina erecta ) with kidney-shaped stomata, and grasses (angiosperms, family Poaceae) with dumbbell-shaped stomata ( Sorghum bicolor and Triticum aestivum ). Three distinct patterns of cellulose crystallinity in stomatal cell walls were observed: Type I (kidney-shaped stomata, ferns), Type II (kidney-shaped stomata, angiosperms) and Type III (dumbbell-shaped stomata, grasses). The different stomatal cell wall attributes investigated (cellulose crystallinity, pectins, lignin, phenolics) exhibited taxon-specific patterns, with reciprocal substitution of structural elements in the end-walls of kidney-shaped stomata. According to a numerical bio-mechanical model, the end walls of kidney-shaped stomata develop the highest stresses during opening. The data presented demonstrate for the first time the existence of distinct spatial patterns of varying cellulose crystallinity in guard cell walls. It is also highly intriguing that in angiosperms crystalline cellulose appears to have replaced lignin that occurs in the stomatal end-walls of ferns serving a similar wall strengthening function. Such taxon-specific spatial patterns of cell wall components could imply different biomechanical functions, which in turn could be a consequence of differences in

  13. Chromatin dynamics during cell cycle mediate conversion of DNA damage into chromatid breaks and affect formation of chromosomal aberrations: Biological and clinical significance

    International Nuclear Information System (INIS)

    Terzoudi, Georgia I.; Hatzi, Vasiliki I.; Donta-Bakoyianni, Catherine; Pantelias, Gabriel E.

    2011-01-01

    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.

  14. Aberrant recombination and repair during immunoglobulin class switching in BRCA1-deficient human B cells

    DEFF Research Database (Denmark)

    Björkman, Andrea; Qvist, Per; Du, Likun

    2015-01-01

    cancer type 2 susceptibility protein (BRCA2)-deficient cells. Thus, BRCA1, together with its interaction partners, seems to play an important role in repairing DSBs generated during class switch recombination by promoting the classical NHEJ pathway. This may not only provide a general mechanism......Breast cancer type 1 susceptibility protein (BRCA1) has a multitude of functions that contribute to genome integrity and tumor suppression. Its participation in the repair of DNA double-strand breaks (DSBs) during homologous recombination (HR) is well recognized, whereas its involvement...... in the second major DSB repair pathway, nonhomologous end-joining (NHEJ), remains controversial. Here we have studied the role of BRCA1 in the repair of DSBs in switch (S) regions during immunoglobulin class switch recombination, a physiological, deletion/recombination process that relies on the classical NHEJ...

  15. Aberrations of the p53 pathway components p53, MDM2 and CDKN2A appear independent in diffuse large B cell lymphoma

    DEFF Research Database (Denmark)

    Møller, Michael Boe; Ino, Y; Gerdes, A M

    1999-01-01

    , whereas p19ARF targets MDM2, a p53 inhibitory protein, for degradation. A deletion of CDKN2A would therefore disturb both pathways. To explore the p53 pathway genes as a functional unit in diffuse large B cell non-Hodgkin's lymphomas (DLCL), we wanted to see whether there exists mutually exclusiveness...... of aberrations of CDKN2A, MDM2 and p53, since this has not been analysed previously. We investigated 37 DLCL for aberrations of p15, p16, p19ARF, MDM2, and p53 at the epigenetic, genetic and/or protein levels. Homozygous deletion of CDKN2A was detected in seven (19%) of 37 tumours, and another three cases were...... and MDM2 overexpression in 16 (43%) tumours. Twenty-three (62%) tumours had alterations of one or more p53 pathway components (p53, p19ARF and MDM2). Furthermore, 7/9 (78%) p16-immunonegative tumours showed co-aberration of p53 and/or MDM2. The lack of correlation between these aberrations suggests...

  16. Reciprocal Interactions between Cadmium-Induced Cell Wall Responses and Oxidative Stress in Plants

    Science.gov (United States)

    Loix, Christophe; Huybrechts, Michiel; Vangronsveld, Jaco; Gielen, Marijke; Keunen, Els; Cuypers, Ann

    2017-01-01

    Cadmium (Cd) pollution renders many soils across the world unsuited or unsafe for food- or feed-orientated agriculture. The main mechanism of Cd phytotoxicity is the induction of oxidative stress, amongst others through the depletion of glutathione. Oxidative stress can damage lipids, proteins, and nucleic acids, leading to growth inhibition or even cell death. The plant cell has a variety of tools to defend itself against Cd stress. First and foremost, cell walls might prevent Cd from entering and damaging the protoplast. Both the primary and secondary cell wall have an array of defensive mechanisms that can be adapted to cope with Cd. Pectin, which contains most of the negative charges within the primary cell wall, can sequester Cd very effectively. In the secondary cell wall, lignification can serve to immobilize Cd and create a tougher barrier for entry. Changes in cell wall composition are, however, dependent on nutrients and conversely might affect their uptake. Additionally, the role of ascorbate (AsA) as most important apoplastic antioxidant is of considerable interest, due to the fact that oxidative stress is a major mechanism underlying Cd toxicity, and that AsA biosynthesis shares several links with cell wall construction. In this review, modifications of the plant cell wall in response to Cd exposure are discussed. Focus lies on pectin in the primary cell wall, lignification in the secondary cell wall and the importance of AsA in the apoplast. Regarding lignification, we attempt to answer the question whether increased lignification is merely a consequence of Cd toxicity, or rather an elicited defense response. We propose a model for lignification as defense response, with a central role for hydrogen peroxide as substrate and signaling molecule. PMID:29163592

  17. Reciprocal Interactions between Cadmium-Induced Cell Wall Responses and Oxidative Stress in Plants

    Directory of Open Access Journals (Sweden)

    Christophe Loix

    2017-10-01

    Full Text Available Cadmium (Cd pollution renders many soils across the world unsuited or unsafe for food- or feed-orientated agriculture. The main mechanism of Cd phytotoxicity is the induction of oxidative stress, amongst others through the depletion of glutathione. Oxidative stress can damage lipids, proteins, and nucleic acids, leading to growth inhibition or even cell death. The plant cell has a variety of tools to defend itself against Cd stress. First and foremost, cell walls might prevent Cd from entering and damaging the protoplast. Both the primary and secondary cell wall have an array of defensive mechanisms that can be adapted to cope with Cd. Pectin, which contains most of the negative charges within the primary cell wall, can sequester Cd very effectively. In the secondary cell wall, lignification can serve to immobilize Cd and create a tougher barrier for entry. Changes in cell wall composition are, however, dependent on nutrients and conversely might affect their uptake. Additionally, the role of ascorbate (AsA as most important apoplastic antioxidant is of considerable interest, due to the fact that oxidative stress is a major mechanism underlying Cd toxicity, and that AsA biosynthesis shares several links with cell wall construction. In this review, modifications of the plant cell wall in response to Cd exposure are discussed. Focus lies on pectin in the primary cell wall, lignification in the secondary cell wall and the importance of AsA in the apoplast. Regarding lignification, we attempt to answer the question whether increased lignification is merely a consequence of Cd toxicity, or rather an elicited defense response. We propose a model for lignification as defense response, with a central role for hydrogen peroxide as substrate and signaling molecule.

  18. Klf1, a C2H2 zinc finger-transcription factor, is required for cell wall maintenance during long-term quiescence in differentiated G0 phase.

    Directory of Open Access Journals (Sweden)

    Mizuki Shimanuki

    Full Text Available Fission yeast, Schizoaccharomyces pombe, is a model for studying cellular quiescence. Shifting to a medium that lacks a nitrogen-source induces proliferative cells to enter long-term G0 quiescence. Klf1 is a Krüppel-like transcription factor with a 7-amino acid Cys2His2-type zinc finger motif. The deletion mutant, ∆klf1, normally divides in vegetative medium, but proliferation is not restored after long-term G0 quiescence. Cell biologic, transcriptomic, and metabolomic analyses revealed a unique phenotype of the ∆klf1 mutant in quiescence. Mutant cells had diminished transcripts related to signaling molecules for switching to differentiation; however, proliferative metabolites for cell-wall assembly and antioxidants had significantly increased. Further, the size of ∆klf1 cells increased markedly during quiescence due to the aberrant accumulation of Calcofluor-positive, chitin-like materials beneath the cell wall. After 4 weeks of quiescence, reversible proliferation ability was lost, but metabolism was maintained. Klf1 thus plays a role in G0 phase longevity by enhancing the differentiation signal and suppressing metabolism for growth. If Klf1 is lost, S. pombe fails to maintain a constant cell size and normal cell morphology during quiescence.

  19. Aberrant activation of hedgehog signaling promotes cell proliferation via the transcriptional activation of forkhead Box M1 in colorectal cancer cells.

    Science.gov (United States)

    Wang, DeJie; Hu, Guohui; Du, Ying; Zhang, Cheng; Lu, Quqin; Lv, Nonghua; Luo, Shiwen

    2017-02-02

    Recent evidence suggests that the aberrant activation of Hedgehog (Hh) signaling by Gli transcription factors is characteristic of a variety of aggressive human carcinomas, including colorectal cancer (CRC). Forkhead box M1 (FoxM1) controls the expression of a number of cell cycle regulatory proteins, and FoxM1 expression is elevated in a broad range of human malignancies, which suggests that it plays a crucial role in tumorigenesis. However, the mechanisms underlying FoxM1 expression are not fully understood. Here, we aim to further investigate the molecular mechanism by which Gli1 regulates FoxM1 in CRC. Western blotting and immunohistochemistry (IHC) were used to evaluate FoxM1 and Gli1 protein expression, respectively, in CRC tissues and matched adjacent normal mucosa. BrdU (5-bromo-2'-deoxyuridine) and clone formation assays were used to clarify the influence of FoxM1 on CRC cell growth and proliferation. Chromatin immunoprecipitation (ChIP) and luciferase experiments were performed to explore the potential mechanisms by which Gli1 regulates FoxM1. Additionally, the protein and mRNA expression levels of Gli1 and FoxM1 in six CRC cell lines were measured using Western blotting and real-time PCR. Finally, the effect of Hh signaling on the expression of FoxM1 was studied in cell biology experiments, and the effects of Hh signaling activation and FoxM1 inhibition on the distribution of CRC cells among cell cycle phases was assessed by flow cytometry. Gli1 and FoxM1 were abnormally elevated in human CRC tissues compared with matched adjacent normal mucosa samples, and FoxM1 is a downstream target gene of the transcription factor Gli1 in CRC and promoted CRC cell growth and proliferation. Moreover, the aberrant activation of Hh signaling promoted CRC cell proliferation by directly binding to the promoter of FoxM1 and transactivating the activity of FoxM1 in CRC cells. The dysregulation of the Hh-Gli1-FoxM1 axis is essential for the proliferation and growth of human

  20. Aberrant proteins in the saliva of patients with oral squamous cell carcinoma.

    Science.gov (United States)

    Jessie, Kala; Jayapalan, Jaime Jacqueline; Ong, Kien-Chai; Abdul Rahim, Zubaidah Haji; Zain, Rosnah Mohd; Wong, Kum-Thong; Hashim, Onn Haji

    2013-09-01

    Confirmation of oral squamous cell cancer (OSCC) currently relies on histological analysis, which does not provide clear indication of cancer development from precancerous lesions. In the present study, whole saliva proteins of patients with OSCC (n = 12) and healthy subjects (n = 12) were separated by 2DE to identify potential candidate biomarkers that are much needed to improve detection of the cancer. The OSCC patients' 2DE saliva protein profiles appeared unique and different from those obtained from the healthy subjects. The patients' saliva α1-antitrypsin (AAT) and haptoglobin (HAP) β chains were resolved into polypeptide spots with increased microheterogeneity, although these were not apparent in their sera. Their 2DE protein profiles also showed presence of hemopexin and α-1B glycoprotein, which were not detected in the profiles of the control saliva. When subjected to densitometry analysis, significant altered levels of AAT, complement C3, transferrin, transthyretin, and β chains of fibrinogen and HAP were detected. The increased levels of saliva AAT, HAP, complement C3, hemopexin, and transthyretin in the OSCC patients were validated by ELISA. The strong association of AAT and HAP with OSCC was further supported by immunohistochemical staining of cancer tissues. The differently expressed saliva proteins may be useful complementary biomarkers for the early detection and/or monitoring of OSCC, although this requires validation in clinically representative populations. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Evolution and diversity of plant cell walls: from algae to flowering plants.

    Science.gov (United States)

    Popper, Zoë A; Michel, Gurvan; Hervé, Cécile; Domozych, David S; Willats, William G T; Tuohy, Maria G; Kloareg, Bernard; Stengel, Dagmar B

    2011-01-01

    All photosynthetic multicellular Eukaryotes, including land plants and algae, have cells that are surrounded by a dynamic, complex, carbohydrate-rich cell wall. The cell wall exerts considerable biological and biomechanical control over individual cells and organisms, thus playing a key role in their environmental interactions. This has resulted in compositional variation that is dependent on developmental stage, cell type, and season. Further variation is evident that has a phylogenetic basis. Plants and algae have a complex phylogenetic history, including acquisition of genes responsible for carbohydrate synthesis and modification through a series of primary (leading to red algae, green algae, and land plants) and secondary (generating brown algae, diatoms, and dinoflagellates) endosymbiotic events. Therefore, organisms that have the shared features of photosynthesis and possession of a cell wall do not form a monophyletic group. Yet they contain some common wall components that can be explained increasingly by genetic and biochemical evidence.

  2. Navigating the transcriptional roadmap regulating plant secondary cell wall deposition

    Directory of Open Access Journals (Sweden)

    Steven Grant Hussey

    2013-08-01

    Full Text Available The current status of lignocellulosic biomass as an invaluable resource in industry, agriculture and health has spurred increased interest in understanding the transcriptional regulation of secondary cell wall (SCW biosynthesis. The last decade of research has revealed an extensive network of NAC, MYB and other families of transcription factors regulating Arabidopsis SCW biosynthesis, and numerous studies have explored SCW-related transcription factors in other dicots and monocots. Whilst the general structure of the Arabidopsis network has been a topic of several reviews, they have not comprehensively represented the detailed protein-DNA and protein-protein interactions described in the literature, and an understanding of network dynamics and functionality has not yet been achieved for SCW formation. Furthermore the methodologies employed in studies of SCW transcriptional regulation have not received much attention, especially in the case of non-model organisms. In this review, we have reconstructed the most exhaustive literature-based network representations to date of SCW transcriptional regulation in Arabidopsis. We include a manipulable Cytoscape representation of the Arabidopsis SCW transcriptional network to aid in future studies, along with a list of supporting literature for each documented interaction. Amongst other topics, we discuss the various components of the network, its evolutionary conservation in plants, putative modules and dynamic mechanisms that may influence network function, and the approaches that have been employed in network inference. Future research should aim to better understand network function and its response to dynamic perturbations, whilst the development and application of genome-wide approaches such as ChIP-seq and systems genetics are in progress for the study of SCW transcriptional regulation in non-model organisms.

  3. Aberrant methylation inactivates somatostatin and somatostatin receptor type 1 in head and neck squamous cell carcinoma.

    Directory of Open Access Journals (Sweden)

    Kiyoshi Misawa

    Full Text Available The aim of this study was to define somatostatin (SST and somatostatin receptor type 1 (SSTR1 methylation profiles for head and neck squamous cell carcinoma (HNSCC tumors at diagnosis and follow up and to evaluate their prognostic significance and value as a biomarker.Gene expression was measured by quantitative RT-PCR. Promoter methylation status was determined by quantitative methylation-specific PCR (Q-MSP in HNSCC.Methylation was associated with transcription inhibition. SST methylation in 81% of HNSCC tumor specimens significantly correlated with tumor size (P = 0.043, stage (P = 0.008, galanin receptor type 2 (GALR2 methylation (P = 0.041, and tachykinin-1 (TAC1 (P = 0.040. SSTR1 hypermethylation in 64% of cases was correlated with tumor size (P = 0.037, stage (P = 0.037, SST methylation (P < 0.001, and expression of galanin (P = 0.03, GALR2 (P = 0.014, TAC1 (P = 0.023, and tachykinin receptor type 1 (TACR1 (P = 0.003. SST and SSTR1 promoter hypermethylation showed highly discriminating receiver operator characteristic curve profiles, which clearly distinguished HNSCC from adjacent normal mucosal tissues. Concurrent hypermethylation of galanin and SSTR1 promoters correlated with reduced disease-free survival (log-rank test, P = 0.0001. Among patients with oral cavity and oropharynx cancer, methylation of both SST and SSTR1 promoters correlated with reduced disease-free survival (log-rank test, P = 0.028. In multivariate logistic-regression analysis, concomitant methylation of galanin and SSTR1 was associated with an odds ratio for recurrence of 12.53 (95% CI, 2.62 to 59.8; P = 0.002.CpG hypermethylation is a likely mechanism of SST and SSTR1 gene inactivation, supporting the hypothesis that SST and SSTR1 play a role in the tumorigenesis of HNSCC and that this hypermethylation may serve as an important biomarker.

  4. Chemical Synthesis of Oligosaccharides related to the Cell Walls of Plants and Algae

    DEFF Research Database (Denmark)

    Kinnaert, Christine; Daugaard, Mathilde; Nami, Faranak

    2017-01-01

    Plant cell walls are composed of an intricate network of polysaccharides and proteins that varies during the developmental stages of the cell. This makes it very challenging to address the functions of individual wall components in cells, especially for highly complex glycans. Fortunately, struct......, and arabinogalactans, as well as glycans unique to algae. Representative synthetic routes within each class are discussed in detail and the progress in carbohydrate chemistry over recent decades is highlighted....

  5. [Ultrastructure and molecular biochemistry on pathogenic fungal cells: the architecture of septal cell walls of dermatophytes].

    Science.gov (United States)

    Kitajima, Y

    2001-01-01

    This review provides abstracts of our research for which the year 2000 prize of The Japanese Society for Medical Mycology was awarded. The study consists of 4 fields: 1)Ultrastructure and biochemistry of the cell walls of dermatophytes. 2) Freeze-fracture electron microscopic study on the membrane systems of pathogenic fungi. 3) Action mechanisms of antifungal agents in terms of membrane structure and functions. 4) Dimorphism and virulence of pathogenic fungi in terms of molecular biology of membrane lipids. Since the detailed contents of these studies were reported in my previous review article (Jpn J Med Mycol 41: 211-217, 2000), I would like to mention these studies only briefly here, together with a detailed review of the septal cell wall architecture of dermatophytes, which I did not cover in my earlier articles.

  6. Aberrant ERK 1/2 complex activation and localization in scrapie-infected GT1-1 cells

    Directory of Open Access Journals (Sweden)

    Didonna Alessandro

    2010-08-01

    Full Text Available Abstract Background Fatal neurodegenerative disorders such as Creutzfeldt-Jakob and Gerstmann-Sträussler-Scheinker diseases in humans, scrapie and bovine spongiform encephalopathy in animals, are characterized by the accumulation in the brain of a pathological form of the prion protein (PrP denominated PrPSc. The latter derives from the host cellular form, PrPC, through a process whereby portions of its α-helical and coil structures are refolded into β-sheet structures. Results In this work, the widely known in vitro model of prion replication, hypothalamic GT1-1 cell line, was used to investigate cellular and molecular responses to prion infection. The MAP kinase cascade was dissected to assess the phosphorylation levels of src, MEK 1/2 and ERK 1/2 signaling molecules, both before and after prion infection. Our findings suggest that prion replication leads to a hyper-activation of this pathway. Biochemical analysis was complemented with immunofluorescence studies to map the localization of the ERK complex within the different cellular compartments. We showed how the ERK complex relocates in the cytosol upon prion infection. We correlated these findings with an impairment of cell growth in prion-infected GT1-1 cells as probed by MTT assay. Furthermore, given the persistent urgency in finding compounds able to cure prion infected cells, we tested the effects on the ERK cascade of two molecules known to block prion replication in vitro, quinacrine and Fab D18. We were able to show that while these two compounds possess similar effects in curing prion infection, they affect the MAP kinase cascade differently. Conclusions Taken together, our results help shed light on the molecular events involved in neurodegeneration and neuronal loss in prion infection and replication. In particular, the combination of chronic activation and aberrant localization of the ERK complex may lead to a lack of essential neuroprotective and survival factors

  7. Xenotransplantation elicits salient tumorigenicity of adult T-cell leukemia-derived cells via aberrant AKT activation.

    Science.gov (United States)

    Yamaguchi, Kazunori; Takanashi, Tomoka; Nasu, Kentaro; Tamai, Keiichi; Mochizuki, Mai; Satoh, Ikuro; Ine, Shoji; Sasaki, Osamu; Satoh, Kennichi; Tanaka, Nobuyuki; Harigae, Hideo; Sugamura, Kazuo

    2016-05-01

    The transplantation of human cancer cells into immunodeficient NOD/SCID/IL-2Rγc(null) (NOG) mice often causes highly malignant cell populations like cancer stem cells to emerge. Here, by serial transplantation in NOG mice, we established two highly tumorigenic adult T-cell leukemia-derived cell lines, ST1-N6 and TL-Om1-N8. When transplanted s.c., these cells formed tumors significantly earlier and from fewer initial cells than their parental lines ST1 and TL-Om1. We found that protein kinase B (AKT) signaling was upregulated in ST1-N6 and TL-Om1-N8 cells, and that this upregulation was due to the decreased expression of a negative regulator, INPP5D. Furthermore, the introduction of a constitutively active AKT mutant expression vector into ST1 cells augmented the tumorigenicity of the cells, whereas treatment with the AKT inhibitor MK-2206 attenuated the progression of tumors induced by ST1-N6 cells. Collectively, our results reveal that the AKT signaling pathway plays a critical role in the malignancy of adult T-cell leukemia-derived cells. © 2016 The Authors. Cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese Cancer Association.

  8. Early local differentiation of the cell wall matrix defines the contact sites in lobed mesophyll cells of Zea mays.

    Science.gov (United States)

    Giannoutsou, E; Sotiriou, P; Apostolakos, P; Galatis, B

    2013-10-01

    The morphogenesis of lobed mesophyll cells (MCs) is highly controlled and coupled with intercellular space formation. Cortical microtubule rings define the number and the position of MC isthmi. This work investigated early events of MC morphogenesis, especially the mechanism defining the position of contacts between MCs. The distributions of plasmodesmata, the hemicelluloses callose and (1 → 3,1 → 4)-β-d-glucans (MLGs) and the pectin epitopes recognized by the 2F4, JIM5, JIM7 and LM6 antibodies were studied in the cell walls of Zea mays MCs. Matrix cell wall polysaccharides were immunolocalized in hand-made sections and in sections of material embedded in LR White resin. Callose was also localized using aniline blue in hand-made sections. Plasmodesmata distribution was examined by transmission electron microscopy. Before reorganization of the dispersed cortical microtubules into microtubule rings, particular bands of the longitudinal MC walls, where the MC contacts will form, locally differentiate by selective (1) deposition of callose and the pectin epitopes recognized by the 2F4, LM6, JIM5 and JIM7 antibodies, (2) degradation of MLGs and (3) formation of secondary plasmodesmata clusterings. This cell wall matrix differentiation persists in cell contacts of mature MCs. Simultaneously, the wall bands between those of future cell contacts differentiate with (1) deposition of local cell wall thickenings including cellulose microfibrils, (2) preferential presence of MLGs, (3) absence of callose and (4) transient presence of the pectins identified by the JIM5 and JIM7 antibodies. The wall areas between cell contacts expand determinately to form the cell isthmi and the cell lobes. The morphogenesis of lobed MCs is characterized by the early patterned differentiation of two distinct cell wall subdomains, defining the sites of the future MC contacts and of the future MC isthmi respectively. This patterned cell wall differentiation precedes cortical microtubule

  9. Elevated CO2 concentration impacts cell wall polysaccharide composition of green microalgae of the genus Chlorella.

    Science.gov (United States)

    Cheng, Y-S; Labavitch, J M; VanderGheynst, J S

    2015-01-01

    The effect of CO2 concentration on the relative content of starch, lipid and cell wall carbohydrates in microalgal biomass was investigated for the four following Chlorella strains: C. vulgaris (UTEX 259), C. sorokiniana (UTEX 2805), C. minutissima (UTEX 2341) and C. variabilis (NC64A). Each strain had a different response to CO2 concentration. The starch content was higher in UTEX259 and NC64A cultured with 2% CO2 in the air supply than in cells cultured with ca. 0·04% CO2 (ambient air), while starch content was not affected for UTEX 2805 and UTEX 2341. The lipid content was higher in Chlorella minutissima UTEX 2341 cultured in 2% CO2 than in cells cultured in ambient air, but was unchanged for the other three strains. All four Chlorella strains tended to have a higher percentage of uronic acids and lower percentage of neutral sugars in their cell wall polysaccharide complement when grown with 2% CO2 supply. Although the percentage of neutral sugars in the cell walls varied with CO2 concentration, the relative proportions of different neutral sugar constituents remained constant for both CO2 conditions. The results demonstrate the importance of considering the effects of CO2 on the cell wall carbohydrate composition of microalgae. Microalgae have the potential to produce products that will reduce society's reliance on fossil fuels and address challenges related to food and feed production. An overlooked yet industrially relevant component of microalgae are their cell walls. Cell wall composition affects cell flocculation and the recovery of intracellular products. In this study, we show that increasing CO2 level results in greater cell wall polysaccharide and uronic acid content in the cell walls of three strains of microalgae. The results have implications on the management of systems for the capture of CO2 and production of fuels, chemicals and food from microalgae. © 2014 The Society for Applied Microbiology.

  10. Recent advances on the posttranslational modifications of EXTs and their roles in plant cell walls

    DEFF Research Database (Denmark)

    Velasquez, Melina; Salter, Juan Salgado; Dorosz, Javier Gloazzo

    2012-01-01

    -glycoproteins on the plant cell wall. Genes conferring the posttranslational modifications, i.e., proline hydroxylation and subsequent O-glycosylation, of the EXTs have been recently identified. In this review we summarize the enzymes that define the O-glycosylation sites on the O-glycoproteins, i.e., the prolyl 4...... and function of extensins in plant cell walls.......The genetic set up and the enzymes that define the O-glycosylation sites and transfer the activated sugars to cell wall glycoprotein Extensins (EXTs) have remained unknown for a long time. We are now beginning to see the emerging components of the molecular machinery that assembles these complex O...

  11. Plectasin, a Fungal Defensin, Targets the Bacterial Cell Wall Precursor Lipid II

    DEFF Research Database (Denmark)

    Schneider, Tanja; Kruse, Thomas; Wimmer, Reinhard

    2010-01-01

    Host defense peptides such as defensins are components of innate immunity and have retained antibiotic activity throughout evolution. Their activity is thought to be due to amphipathic structures, which enable binding and disruption of microbial cytoplasmic membranes. Contrary to this, we show...... that plectasin, a fungal defensin, acts by directly binding the bacterial cell-wall precursor Lipid II. A wide range of genetic and biochemical approaches identify cell-wall biosynthesis as the pathway targeted by plectasin. In vitro assays for cell-wall synthesis identified Lipid II as the specific cellular...

  12. Tyrosine kinase receptor c-ros-oncogene 1 inhibition alleviates aberrant bone formation of TWIST-1 haploinsufficient calvarial cells from Saethre-Chotzen syndrome patients.

    Science.gov (United States)

    Camp, Esther; Anderson, Peter J; Zannettino, Andrew C W; Glackin, Carlotta A; Gronthos, Stan

    2018-04-16

    Saethre-Chotzen syndrome (SCS), associated with TWIST-1 mutations, is characterized by premature fusion of cranial sutures. TWIST-1 haploinsufficiency, leads to alterations in suture mesenchyme cellular gene expression patterns, resulting in aberrant osteogenesis and craniosynostosis. We analyzed the expression of the TWIST-1 target, Tyrosine kinase receptor c-ros-oncogene 1 (C-ROS-1) in TWIST-1 haploinsufficient calvarial cells derived from SCS patients and calvaria of Twist-1 del/+ mutant mice and found it to be highly expressed when compared to TWIST-1 wild-type controls. Knock-down of C-ROS-1 expression in TWIST-1 haploinsufficient calvarial cells derived from SCS patients was associated with decreased capacity for osteogenic differentiation in vitro. Furthermore, treatment of human SCS calvarial cells with the tyrosine kinase chemical inhibitor, Crizotinib, resulted in reduced C-ROS-1 activity and the osteogenic potential of human SCS calvarial cells with minor effects on cell viability or proliferation. Cultured human SCS calvarial cells treated with Crizotinib exhibited a dose-dependent decrease in alkaline phosphatase activity and mineral deposition, with an associated decrease in expression levels of Runt-related transcription factor 2 and OSTEOPONTIN, with reduced PI3K/Akt signalling in vitro. Furthermore, Crizotinib treatment resulted in reduced BMP-2 mediated bone formation potential of whole Twist-1 del/+ mutant mouse calvaria organotypic cultures. Collectively, these results suggest that C-ROS-1 promotes osteogenic differentiation of TWIST-1 haploinsufficient calvarial osteogenic progenitor cells. Furthermore, the aberrant osteogenic potential of these cells is inhibited by the reduction of C-ROS-1. Therefore, targeting C-ROS-1 with a pharmacological agent, such as Crizotinib, may serve as a novel therapeutic strategy to alleviate craniosynostosis associated with aberrant TWIST-1 function. © 2018 Wiley Periodicals, Inc.

  13. The role of cell wall revealed by the visualization of Saccharomyces cerevisiae transformation.

    Science.gov (United States)

    Pham, Tuan Anh; Kawai, Shigeyuki; Kono, Emi; Murata, Kousaku

    2011-03-01

    Transformation is an indispensable method for the manipulation of Saccharomyces cerevisiae cell. The spf1 cell, in which the gene encoding an endoplasmic reticulum-located P-type ATPase is deleted, has been known to show the high-transformation phenotype. In this study, fluorescent microscopic observation of transformation process of S. cerevisiae using plasmid DNA labelled with fluorescent DNA probe, YOYO-1, suggested that the spf1 cell absorbed more plasmid DNA on cellular surface than did the wild-type cell and the unwashed cell did more plasmid DNA than the washed cell. The amounts of the absorbed DNA correlated with the transformation efficiency (number of transformants per μg plasmid DNA) and frequency (transformation efficiency per viable cell number). The high-transformation phenotype of spf1 cell and the effect of heat shock, which effectively induces the transformation of intact cell, disappeared upon cell wall digestion. Electron microscopic observation of the transformation process using negatively charged Nanogold as a mimic of plasmid DNA supported the result obtained using YOYO-1 and implied that plasmid DNA enters into cell together with membrane structure. These data strongly suggest that during the transformation of intact cell, plasmid DNA is initially absorbed on the cell wall, passes through the cell wall with the aid of heat shock, reaches to the membrane, and enters into the cell together with the membrane structure and that the capacity of the cell wall to absorb DNA is at least one of the determinants of transformation efficiency and frequency.

  14. Interplays between the cell wall and phytohormones in interaction between plants and necrotrophic pathogens.

    Science.gov (United States)

    Nafisi, Majse; Fimognari, Lorenzo; Sakuragi, Yumiko

    2015-04-01

    The plant cell wall surrounds every cell in plants. During microbial infection, the cell wall provides a dynamic interface for interaction with necrotrophic phytopathogens as a rich source of carbohydrates for the growth of pathogens, as a physical barrier restricting the progression of the pathogens, and as an integrity sensory system that can activate intracellular signaling cascades and ultimately lead to a multitude of inducible host defense responses. Studies over the last decade have provided evidence of interplays between the cell wall and phytohormone signaling. This review summarizes the current state of knowledge about the cell wall-phytohormone interplays, with the focus on auxin, cytokinin, brassinosteroids, and abscisic acid, and discuss how they impact the outcome of plant-necrotrophic pathogen interaction. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  15. Detection of wood cell wall porosity using small carbohydrate molecules and confocal fluorescence microscopy.

    Science.gov (United States)

    Donaldson, L A; Kroese, H W; Hill, S J; Franich, R A

    2015-09-01

    A novel approach to nanoscale detection of cell wall porosity using confocal fluorescence microscopy is described. Infiltration of cell walls with a range of nitrophenyl-substituted carbohydrates of different molecular weights was assessed by measuring changes in the intensity of lignin fluorescence, in response to the quenching effect of the 4-nitrophenyl group. The following carbohydrates were used in order of increasing molecular weight; 4-nitrophenyl β-D-glucopyrano-side (monosaccharide), 4-nitrophenyl β-D-lactopyranoside (disaccharide), 2-chloro-4-nitrophenyl β-D-maltotrioside (trisaccharide), and 4-nitrophenyl α-D-maltopentaoside (pentasaccharide). This technique was used to compare cell wall porosity in wood which had been dewatered to 40% moisture content using supercritical CO2, where cell walls remain fully hydrated, with kiln dried wood equilibrated to 12% moisture content. Infiltration of cell walls as measured by fluorescence quenching, was found to decrease with increasing molecular weight, with the pentasaccharide being significantly excluded compared to the monosaccharide. Porosity experiments were performed on blocks and sections to assess differences in cell wall accessibility. Dewatered and kiln dried wood infiltrated as blocks showed similar results, but greater infiltration was achieved by using sections, indicating that not all pores were easily accessible by infiltration from the lumen surface. In wood blocks infiltrated with 4-nitrophenyl α-D-maltopentaoside, quenching of the secondary wall was quite variable, especially in kiln dried wood, indicating limited connectivity of pores accessible from the lumen surface. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  16. Dual Roles of FmtA in Staphylococcus aureus Cell Wall Biosynthesis and Autolysis

    Science.gov (United States)

    Qamar, Aneela

    2012-01-01

    The fmtA gene is a member of the Staphylococcus aureus core cell wall stimulon. The FmtA protein interacts with β-lactams through formation of covalent species. Here, we show that FmtA has weak d-Ala-d-Ala-carboxypeptidase activity and is capable of covalently incorporating C14-Gly into cell walls. The fluorescence microscopy study showed that the protein is localized to the cell division septum. Furthermore, we show that wall teichoic acids interact specifically with FmtA and mediate recruitment of FmtA to the S. aureus cell wall. Subjection of S. aureus to FmtA concentrations of 0.1 μM or less induces autolysis and biofilm production. This effect requires the presence of wall teichoic acids. At FmtA concentrations greater than 0.2 μM, autolysis and biofilm formation in S. aureus are repressed and growth is enhanced. Our findings indicate dual roles of FmtA in S. aureus growth, whereby at low concentrations, FmtA may modulate the activity of the major autolysin (AtlA) of S. aureus and, at high concentrations, may participate in synthesis of cell wall peptidoglycan. These two roles of FmtA may reflect dual functions of FmtA in the absence and presence of cell wall stress, respectively. PMID:22564846

  17. Current Models for Transcriptional Regulation of Secondary Cell Wall Biosynthesis in Grasses

    Directory of Open Access Journals (Sweden)

    Xiaolan Rao

    2018-04-01

    Full Text Available Secondary cell walls mediate many crucial biological processes in plants including mechanical support, water and nutrient transport and stress management. They also provide an abundant resource of renewable feed, fiber, and fuel. The grass family contains the most important food, forage, and biofuel crops. Understanding the regulatory mechanism of secondary wall formation in grasses is necessary for exploiting these plants for agriculture and industry. Previous research has established a detailed model of the secondary wall regulatory network in the dicot model species Arabidopsis thaliana. Grasses, branching off from the dicot ancestor 140–150 million years ago, display distinct cell wall morphology and composition, suggesting potential for a different secondary wall regulation program from that established for dicots. Recently, combined application of molecular, genetic and bioinformatics approaches have revealed more transcription factors involved in secondary cell wall biosynthesis in grasses. Compared with the dicots, grasses exhibit a relatively conserved but nevertheless divergent transcriptional regulatory program to activate their secondary cell wall development and to coordinate secondary wall biosynthesis with other physiological processes.

  18. Periplasm turgor pressure controls wall deposition and assembly in growing Chara corallina cells.

    Science.gov (United States)

    Proseus, Timothy E; Boyer, John S

    2006-07-01

    New wall deposition usually accompanies plant growth. External osmotica inhibit both processes but wall precursors continue to be synthesized, and exocytosis follows. Consequently, the osmotica appear to act outside of the plasma membrane. Because this implies an action of turgor pressure (P) on the periplasm by unknown mechanisms, the following study was undertaken to determine whether P could act in a way that altered wall deposition and assembly in the periplasm while the cells grow. Cells of Chara corallina were exposed to P slightly below normal by using a pressure probe while supplying inorganic carbon in light. After labelling, the walls were isolated and the amount of new wall was determined. Similar measurements were made after treatment with osmotica. Chlortetracycline-stimulated exocytosis was determined microscopically. Polysaccharide properties were determined by confocal microscopy and vapour pressure osmometry in an 'artificial periplasm' in isolated Chara cell walls, using labelled dextran as an analogue of hemicellulose, and polygalacturonate as pectin. Rapid growth and wall deposition occurred at normal P of 0.5 MPa but both processes decreased when P was lowered 0.1 MPa. Inorganic carbon uptake and exocytosis were unaffected. In the artificial periplasm, normal P caused high polysaccharide concentrations and rapid polysaccharide entry into the wall, and gel formation in the pectin. Lowering P decreased entry and gel formation. This is the first indication that normal P of 0.5 MPa can concentrate periplasmic polysaccharides sufficiently to cause cross-linking and gel formation in pectins while simultaneously fostering the entry of large polysaccharides into small interstices in the existing wall. This P-action would thicken the primary wall and form a smooth transition between the new and old structure, suggesting a molecular mechanism of wall deposition and assembly while the wall extends.

  19. Changes in cell wall architecture of wheat coleoptiles grown under continuous hypergravity conditions

    Science.gov (United States)

    Wakabayashi, K.; Soga, K.; Kamisaka, S.; Hoson, T.

    Modifications of cell wall structure of wheat coleoptiles in response to continuous hypergravity (300 g) treatment were investigated. Length of coleoptiles exposed to hypergravity for 2-4 days from germination stage was 60-70% of that of 1 g control. The net amounts of cell wall polysaccharides, such as hemicellulose and cellulose, of hypergravity-treated coleoptiles increased as much as those of 1 g control coleoptiles during the incubation period. As a result, the levels of cell wall polysaccharides per unit length of coleoptile, which mean the thickness of cell walls, largely increased under hypergravity conditions. Particularly, the amounts of hemicellulosic polymers with middle molecular mass (0.2-1 MDa) largely increased from day 2 to 3 under hypergravity conditions. The major sugar components of the hemicellulose fraction are arabinose, xylose and glucose. The ratios of arabinose and xylose to glucose were higher in hypergravity-treated coleoptiles than in control coleoptiles. The fractionation of hemicellulosic polymers into the neutral and acidic polymers by the anion-exchange column showed that the levels of acidic polymers (mainly composed of arabinoxylans) in cell walls of hypergravity-treated coleoptiles were higher than those of control coleoptiles. In addition to wall polysaccharides, the amounts of cell wall-bound phenolics, such as ferulic acid and diferulic acid, substantially increased during the incubation period both in 1 g control and hypergravity-treated coleoptiles. Especially, the levels of diferulic acid which cross-links hemicellulosic polymers were higher in hypergravity-treated coleoptiles than in control coleoptiles during the incubation period. These results suggest that hypergravity stimuli from the germination stage bias the type of synthesized hemicellulosic polysaccharides, although they do not restrict the net synthesis of cell wall constituents in wheat coleoptiles. The stimulation of the synthesis of arabinoxylans and of the

  20. Expression of S-adenosylmethionine Hydrolase in Tissues Synthesizing Secondary Cell Walls Alters Specific Methylated Cell Wall Fractions and Improves Biomass Digestibility

    Directory of Open Access Journals (Sweden)

    Aymerick Eudes

    2016-07-01

    Full Text Available Plant biomass is a large source of fermentable sugars for the synthesis of bioproducts using engineered microbes. These sugars are stored as cell wall polymers, mainly cellulose and hemicellulose, and are embedded with lignin, which makes their enzymatic hydrolysis challenging. One of the strategies to reduce cell wall recalcitrance is the modification of lignin content and composition. Lignin is a phenolic polymer of methylated aromatic alcohols and its synthesis in tissues developing secondary cell walls is a significant sink for the consumption of the methyl donor S-adenosylmethionine (AdoMet. In this study, we demonstrate in Arabidopsis stems that targeted expression of S-adenosylmethionine hydrolase (AdoMetase, E.C. 3.3.1.2 in secondary cell-wall synthesizing tissues reduces the AdoMet pool and impacts lignin content and composition. In particular, both NMR analysis and pyrolysis gas chromatography mass spectrometry of lignin in engineered biomass showed relative enrichment of non-methylated p-hydroxycinnamyl (H units and a reduction of dimethylated syringyl (S units. This indicates a lower degree of methylation compared to that in wild-type lignin. Quantification of cell wall-bound hydroxycinnamates revealed a reduction of ferulate in AdoMetase transgenic lines. Biomass from transgenic lines, in contrast to that in control plants, exhibits an enrichment of glucose content and a reduction in the degree of hemicellulose glucuronoxylan methylation. We also show that these modifications resulted in a reduction of cell wall recalcitrance, because sugar yield generated by enzymatic biomass saccharification was greater than that of wild type plants. Considering that transgenic plants show no important diminution of biomass yields, and that heterologous expression of AdoMetase protein can be spatiotemporally optimized, this novel approach provides a valuable option for the improvement of lignocellulosic biomass feedstock.

  1. Arabidopsis Seed Coat Mucilage is a Specialized Cell Wall that Can be Used as a Model for Genetic Analysis of Plant Cell Wall Structure and Function

    OpenAIRE

    Haughn, George W.; Western, Tamara L.

    2012-01-01

    Arabidopsis seed coat epidermal cells produce a large quantity of mucilage that is extruded upon exposure to water. Chemical analyses and cell biological techniques suggest that this mucilage represents a specialized type of secondary cell wall composed primarily of pectin with lesser amounts of cellulose and xyloglucan. Once extruded, the mucilage capsule has a distinctive structure with an outer non-adherent layer that is easily removed by shaking in water, and an inner adherent layer that ...

  2. 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.

  3. The plant secretory pathway seen through the lens of the cell wall.

    Science.gov (United States)

    van de Meene, A M L; Doblin, M S; Bacic, Antony

    2017-01-01

    Secretion in plant cells is often studied by looking at well-characterised, evolutionarily conserved membrane proteins associated with particular endomembrane compartments. Studies using live cell microscopy and fluorescent proteins have illuminated the highly dynamic nature of trafficking, and electron microscopy studies have resolved the ultrastructure of many compartments. Biochemical and molecular analyses have further informed about the function of particular proteins and endomembrane compartments. In plants, there are over 40 cell types, each with highly specialised functions, and hence potential variations in cell biological processes and cell wall structure. As the primary function of secretion in plant cells is for the biosynthesis of cell wall polysaccharides and apoplastic transport complexes, it follows that utilising our knowledge of cell wall glycosyltransferases (GTs) and their polysaccharide products will inform us about secretion. Indeed, this knowledge has led to novel insights into the secretory pathway, including previously unseen post-TGN secretory compartments. Conversely, our knowledge of trafficking routes of secretion will inform us about polarised and localised deposition of cell walls and their constituent polysaccharides/glycoproteins. In this review, we look at what is known about cell wall biosynthesis and the secretory pathway and how the different approaches can be used in a complementary manner to study secretion and provide novel insights into these processes.

  4. Turnover of galactans and other cell wall polysaccharides during development of flax plants

    International Nuclear Information System (INIS)

    Gorshkova, T.A.; Chemikosova, S.B.; Lozovaya, V.V.; Carpita, N.C.

    1997-01-01

    We investigated the synthesis and turnover of cell wall polysaccharides of the flax (Linum usitatissimum L.) plant during development of the phloem fibers. One-month-old flax plants were exposed to a 40-min pulse with 14CO2 followed by 8-h, 24-h, and 1-month periods of chase with ambient CO2, and radioactivity in cell wall sugars was determined in various plant parts. The relative radioactivity of glucose in noncellulosic polysaccharides was the highest compared with all other cell wall sugars immediately after the pulse and decreased substantially during the subsequent chase. The relative radioactivities of the other cell wall sugars changed with differing rates, indicating turnover of specific polysaccharides. Notably, after 1 month of chase there was a marked decrease in the proportional mass and total radioactivity in cell wall galactose, indicating a long-term turnover of the galactans enriched in the fiber-containing tissues. The ratio of radiolabeled xylose to arabinose also increased during the chase, indicating a turnover of arabinose-containing polymers and interconversion to xylose. The pattern of label redistribution differed between organs, indicating that the cell wall turnover processes are tissue- and cell-specific

  5. Intestinal epithelial cell-specific RARα depletion results in aberrant epithelial cell homeostasis and underdeveloped immune system.

    Science.gov (United States)

    Jijon, H B; Suarez-Lopez, L; Diaz, O E; Das, S; De Calisto, J; Yaffe, M B; Pittet, M J; Mora, J R; Belkaid, Y; Xavier, R J; Villablanca, E J

    2017-11-15

    Retinoic acid (RA), a dietary vitamin A metabolite, is crucial in maintaining intestinal homeostasis. RA acts on intestinal leukocytes to modulate their lineage commitment and function. Although the role of RA has been characterized in immune cells, whether intestinal epithelial cells (IECs) rely on RA signaling to exert their immune-regulatory function has not been examined. Here we demonstrate that lack of RA receptor α (RARα) signaling in IECs results in deregulated epithelial lineage specification, leading to increased numbers of goblet cells and Paneth cells. Mechanistically, lack of RARα resulted in increased KLF4 + goblet cell precursors in the distal bowel, whereas RA treatment inhibited klf4 expression and goblet cell differentiation in zebrafish. These changes in secretory cells are associated with increased Reg3g, reduced luminal bacterial detection, and an underdeveloped intestinal immune system, as evidenced by an almost complete absence of lymphoid follicles and gut resident mononuclear phagocytes. This underdeveloped intestinal immune system shows a decreased ability to clear infection with Citrobacter rodentium. Collectively, our findings indicate that epithelial cell-intrinsic RARα signaling is critical to the global development of the intestinal immune system.Mucosal Immunology advance online publication, 15 November 2017; doi:10.1038/mi.2017.91.

  6. X-ray-induced chromosomal aberrations and cell killing in somatic and germ cells of the scid mouse

    NARCIS (Netherlands)

    van Buul, P. P.; de rooij, D. G.; Zandman, I. M.; Grigorova, M.; van Duyn-Goedhart, A.

    1995-01-01

    To characterize further the radiosensitivity of severe combined immunodeficiency (scid) mice, the induction of micronuclei (MN) in polychromatic erythrocytes as well as cell killing and translocation induction in stem cell spermatogonia was studied. Scid mice turned out to be clearly hypersensitive

  7. Size, Shape, and Arrangement of Cellulose Microfibril in Higher Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Ding, S. Y.

    2013-01-01

    Plant cell walls from maize (Zea mays L.) are imaged using atomic force microscopy (AFM) at the sub-nanometer resolution. We found that the size and shape of fundamental cellulose elementary fibril (CEF) is essentially identical in different cell wall types, i.e., primary wall (PW), parenchyma secondary wall (pSW), and sclerenchyma secondary wall (sSW), which is consistent with previously proposed 36-chain model (Ding et al., 2006, J. Agric. Food Chem.). The arrangement of individual CEFs in these wall types exhibits two orientations. In PW, CEFs are horizontally associated through their hydrophilic faces, and the planar faces are exposed, forming ribbon-like macrofibrils. In pSW and sSW, CEFs are vertically oriented, forming layers, in which hemicelluloses are interacted with the hydrophobic faces of the CEF and serve as spacers between CEFs. Lignification occurs between CEF-hemicelluloses layers in secondary walls. Furthermore, we demonstrated quantitative analysis of plant cell wall accessibility to and digestibility by different cellulase systems at real-time using chemical imaging (e.g., stimulated Raman scattering) and fluorescence microscopy of labeled cellulases (Ding et al., 2012, Science, in press).

  8. Identification of polysaccharide hydrolases involved in autolytic degradation of Zea cell walls

    International Nuclear Information System (INIS)

    Nock, L.P.; Smith, C.J.

    1987-01-01

    Cell walls of Zea mays (cv L.G.11) seedlings labeled with 14 C were treated with α-amylase from Bacillus subtilis to remove starch and mixed linkage glucans. These walls released arabinose, xylose, galactose, and galacturonic acid in addition to glucose when they were allowed to autolyze. Methylation analysis was performed on samples of wall which had been incubated autolytically and the results indicated that degradation of the major polymer of the wall, the glucoarabinoxylan, had occurred. A number of glycanases could be dissociated from the wall by use of 3 M LiCL. The proteins which were released were found to contain a number of exoglycosidase activities in addition to being effective in degrading the polysaccharide substrates, araban, xylan, galactan, laminarin, mannan, and polygalacturonic acid. The effects of these enzymes on the wall during autolysis appear to result from endo-activity in addition to exo-activity. The structural changes that occurred in the cell walls during autolysis were found to be related to the changes previously found to occur in cell walls during auxin induced extension

  9. Ultrastructural changes of cell walls under intense mechanical treatment of selective plant raw material

    International Nuclear Information System (INIS)

    Bychkov, Aleksey L.; Ryabchikova, E.I.; Korolev, K.G.; Lomovsky, O.I.

    2012-01-01

    Structural changes of cell walls under intense mechanical treatment of corn straw and oil-palm fibers were studied by electron and light microscopy. Differences in the character of destruction of plant biomass were revealed, and the dependence of destruction mechanisms on the structure of cell walls and lignin content was demonstrated. We suggest that the high reactivity of the particles of corn straw (about 18% of lignin) after intense mechanical treatment is related to disordering of cell walls and an increase of the surface area, while in the case of oil palm (10% of lignin) the major contribution into an increase in the reactivity is made by an increase of surface area. -- Highlights: ► Structure of cell walls determines the processes of plant materials' destruction. ► Ultrastructure of highly lignified materials strongly disordering by mechanical action. ► Ultrastructure of low-lignified materials is not disordering by mechanical action.

  10. Zinc octacarboxyphthalocyanine/Multi-walled carbon nanotubes hybrid for the development of dye solar cells

    CSIR Research Space (South Africa)

    Mphahlele, N

    2010-09-01

    Full Text Available octacarboxyphthalocyanine / Multi-walled Carbon Nanotubes Hybrid for the Development of Dye Solar Cells Nonhlanhla Mphahlele Materials Science & Manufacturing: Energy & Processes (EaP) 7 September 2010 OUTLINE ? INTRODUCTION ? OBJECTIVES ? EXPERIMENTAL PROCEDURE...

  11. 2012 PLANT CELL WALLS GORDON RESEARCH CONFERENCE AND GORDON RESEARCH SEMINAR, AUGUST 4-10, 2012

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Jocelyn

    2012-08-10

    The sub-theme of this year’s meeting, ‘Cell Wall Research in a Post-Genome World’, will be a consideration of the dramatic technological changes that have occurred in the three years since the previous cell wall Gordon Conference in the area of DNA sequencing. New technologies are providing additional perspectives of plant cell wall biology across a rapidly growing number of species, highlighting a myriad of architectures, compositions, and functions in both "conventional" and specialized cell walls. This meeting will focus on addressing the knowledge gaps and technical challenges raised by such diversity, as well as our need to understand the underlying processes for critical applications such as crop improvement and bioenergy resource development.

  12. How does plant cell wall nanoscale architecture correlate with enzymatic digestibility?

    Science.gov (United States)

    Ding, Shi-You; Liu, Yu-San; Zeng, Yining; Himmel, Michael E; Baker, John O; Bayer, Edward A

    2012-11-23

    Greater understanding of the mechanisms contributing to chemical and enzymatic solubilization of plant cell walls is critical for enabling cost-effective industrial conversion of cellulosic biomass to biofuels. Here, we report the use of correlative imaging in real time to assess the impact of pretreatment, as well as the resulting nanometer-scale changes in cell wall structure, upon subsequent digestion by two commercially relevant cellulase systems. We demonstrate that the small, noncomplexed fungal cellulases deconstruct cell walls using mechanisms that differ considerably from those of the larger, multienzyme complexes (cellulosomes). Furthermore, high-resolution measurement of the microfibrillar architecture of cell walls suggests that digestion is primarily facilitated by enabling enzyme access to the hydrophobic cellulose face. The data support the conclusion that ideal pretreatments should maximize lignin removal and minimize polysaccharide modification, thereby retaining the essentially native microfibrillar structure.

  13. The Paracoccidioides cell wall: past and present layers towards understanding interaction with the host

    Directory of Open Access Journals (Sweden)

    Rosana ePuccia

    2011-12-01

    Full Text Available The cell wall of pathogenic fungi plays import roles in interaction with the host, so that its composition and structure may determine the course of infection. Here we present an overview of the current and past knowledge on the cell wall constituents of Paracoccidioides brasiliensis and P. lutzii. These are temperature-dependent dimorphic fungi that cause paracoccidioidomycosis, a systemic granulomatous and debilitating disease. Focus is given on cell wall carbohydrate and protein contents, their immune-stimulatory features, adhesion properties, drug target characteristics, and morphological phase specificity. We offer a journey towards the future understanding of the dynamic life that takes place in the cell wall and of the changes that it may suffer when living in the human host.

  14. The relation of apple texture with cell wall nanostructure studied using an atomic force microscope.

    Science.gov (United States)

    Cybulska, Justyna; Zdunek, Artur; Psonka-Antonczyk, Katarzyna M; Stokke, Bjørn T

    2013-01-30

    In this study, the relation of the nanostructure of cell walls with their texture was investigated for six different apple cultivars. Cell wall material (CWM) and cellulose microfibrils were imaged by atomic force microscope (AFM). The mean diameter of cellulose microfibrils for each cultivar was estimated based on the AFM height topographs obtained using the tapping mode of dried specimens. Additionally, crystallinity of cellulose microfibrils and pectin content was determined. Texture of apple cultivars was evaluated by sensory and instrumental analysis. Differences in cellulose diameter as determined from the AFM height topographs of the nanostructure of cell walls of the apple cultivars are found to relate to the degree of crystallinity and pectin content. Cultivars with thicker cellulose microfibrils also revealed crisper, harder and juicier texture, and greater acoustic emission. The data suggest that microfibril thickness affects the mechanical strength of cell walls which has consequences for sensory and instrumental texture. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Cell wall degrading enzymes in Trichoderma asperellum grown on wheat bran

    DEFF Research Database (Denmark)

    Bech, Lasse; Busk, Peter Kamp; Lange, Lene

    2015-01-01

    Trichoderma asperellum is a filamentous fungus that is able to produce and secrete a wide range of extracellular hydrolytic enzymes used for plant cell wall degradation. The Trichoderma genus has attracted considerable attention from the biorefinery industry due to the production of cell wall...... degrading enzymes and strong secretion ability of this genus. Here we report extensive transcriptome analysis of plant cell wall degrading enzymes in T. asperellum. The production of cell wall degrading enzymes by T. asperellum was tested on a range of cellulosic materials under various conditions. When T...... the theory that the glycoside hydrolases have evolved from a common ancestor, followed by a specialization in which saprotrophic fungi such as T. reesei and T. longibrachiatum lost a significant number of genes including several glycoside hydrolases....

  16. Reducing cell wall feruloylation by expression of a fungal ferulic acid esterase in Festuca arundinacea modifies plant growth, leaf morphology and the turnover of cell wall arabinoxylans

    Science.gov (United States)

    Iyer, Prashanti R.; Buanafina, M. Fernanda; Shearer, Erica A.

    2017-01-01

    A feature of cell wall arabinoxylan in grasses is the presence of ferulic acid which upon oxidative coupling by the action of peroxidases forms diferuloyl bridges between formerly separated arabinoxylans. Ferulate cross-linking is suspected of playing various roles in different plant processes. Here we investigate the role of cell wall feruloyaltion in two major processes, that of leaf growth and the turnover of cell wall arabinoxylans on leaf senescence in tall fescue using plants in which the level of cell wall ferulates has been reduced by targeted expression of the Aspergillus niger ferulic acid esterase A (FAEA) to the apoplast or Golgi. Analysis of FAE expressing plants showed that all the lines had shorter and narrower leaves compared to control, which may be a consequence of the overall growth rate being lower and occurring earlier in FAE expressing leaves than in controls. Furthermore, the final length of epidermal cells was shorter than controls, indicating that their expansion was curtailed earlier than in control leaves. This may be due to the observations that the deposition of both ether and ester linked monomeric hydroxycinnamic acids and ferulate dimerization stopped earlier in FAE expressing leaves but at a lower level than controls, and hydroxycinnamic acid deposition started to slow down when peroxidase levels increased. It would appear therefore that one of the possible mechanisms for controlling overall leaf morphology such as leaf length and width in grasses, where leaf morphology is highly variable between species, may be the timing of hydroxycinnamic acid deposition in the expanding cell walls as they emerge from cell division into the elongation zone, controlled partially by the onset of peroxidase activity in this region. PMID:28934356

  17. Modeling chronic myeloid leukemia in immunodeficient mice reveals expansion of aberrant mast cells and accumulation of pre-B cells

    International Nuclear Information System (INIS)

    Askmyr, M; Ågerstam, H; Lilljebjörn, H; Hansen, N; Karlsson, C; Palffy, S von; Landberg, N; Högberg, C; Lassen, C; Rissler, M; Richter, J; Ehinger, M; Järås, M; Fioretos, T

    2014-01-01

    Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that, if not treated, will progress into blast crisis (BC) of either myeloid or B lymphoid phenotype. The BCR-ABL1 fusion gene, encoding a constitutively active tyrosine kinase, is thought to be sufficient to cause chronic phase (CP) CML, whereas additional genetic lesions are needed for progression into CML BC. To generate a humanized CML model, we retrovirally expressed BCR-ABL1 in the cord blood CD34 + cells and transplanted these into NOD-SCID (non-obese diabetic/severe-combined immunodeficient) interleukin-2-receptor γ-deficient mice. In primary mice, BCR-ABL1 expression induced an inflammatory-like state in the bone marrow and spleen, and mast cells were the only myeloid lineage specifically expanded by BCR-ABL1. Upon secondary transplantation, the pronounced inflammatory phenotype was lost and mainly human mast cells and macrophages were found in the bone marrow. Moreover, a striking block at the pre-B-cell stage was observed in primary mice, resulting in an accumulation of pre-B cells. A similar block in B-cell differentiation could be confirmed in primary cells from CML patients. Hence, this humanized mouse model of CML reveals previously unexplored features of CP CML and should be useful for further studies to understand the disease pathogenesis of CML

  18. Characterisation of Rosa Mosqueta seeds : cell wall polysaccharide composition and light microscopy observations

    OpenAIRE

    Dourado, Fernando; Vasco, Pedro; Gama, F. M.; Coimbra, Manuel A.; Mota, M.

    2000-01-01

    The utilisation of enzymes for the extraction of vegetable oils from seeds has been a topic of growing interest in recent years. Knowledge of the cell wall polysaccharide composition is important to select the enzyme(s) necessary for the most effective degradation of the cell walls. The purpose of the present work is to characterise the seeds of Rosa Mosqueta (Rosa aff rubiginosa) by light microscopy (where several differential staining methods were applied to analyse the seed structure...

  19. Identification of Bacillus anthracis by Using Monoclonal Antibody to Cell Wall Galactose-N-Acetylglucosamine Polysaccharide

    Science.gov (United States)

    1990-02-01

    Bacillus circulans ATCC 4513 b - - NR NT NT NT NT Bacillus coagulans ATCC 7050 b - - NR NT NT NT NT Bacillus eugilitis B-61 f - - NR NT NT NT NT...American Society for Microbiology W Identification of Bacillus anthracis by-U-sing Monoclonal Antibody CC to Cell Wall Galactose-N-Acetylglucosamine...Received 22 June 1989/Accepted 31 October 1989 ’ Guanidine extracts of crude Bacillus anthracis cell wall were used to vaccinate BALB/c mice and to

  20. Detection of 2 immunoreactive antigens in the cell wall of Sporothrix brasiliensis and Sporothrix globosa.

    Science.gov (United States)

    Ruiz-Baca, Estela; Hernández-Mendoza, Gustavo; Cuéllar-Cruz, Mayra; Toriello, Conchita; López-Romero, Everardo; Gutiérrez-Sánchez, Gerardo

    2014-07-01

    The cell wall of members of the Sporothrix schenckii complex contains highly antigenic molecules which are potentially useful for the diagnosis and treatment of sporotrichosis. In this study, 2 immunoreactive antigens of 60 (Gp60) and 70 kDa (Gp70) were detected in the cell wall of the yeast morphotypes of Sporothrix brasiliensis and Sporothrix globosa. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Chemical composition, anatomy, lignin distribution, and cell wall structure of Malaysian plant waste fibers

    OpenAIRE

    Mohd Omar, A. K.; Siti Alwani, M.; Abdul Khalil, H. P. S.

    2006-01-01

    The chemical composition, anatomical characteristics, lignin distribution, and cell wall structure of oil palm frond (OPF), coconut (COIR), pine-apple leaf (PALF), and banana stem (BS) fibers were analyzed. The chemical composition of fiber was analyzed according to TAPPI Methods. Light microscopy (LM) and transmission electron microscopy (TEM) were used to observe and determine the cell wall structure and lignin distribution of various agro-waste fibers. The results revealed differences in a...

  2. A cytochemical and immunocytochemical analysis of the wall labyrinth apparatus in leaf transfer cells in Elodea canadensis.

    Science.gov (United States)

    Ligrone, Roberto; Vaughn, Kevin C; Rascio, Nicoletta

    2011-04-01

    Transfer cells are plant cells specialized in apoplast/symplast transport and characterized by a distinctive wall labyrinth apparatus. The molecular architecture and biochemistry of the labyrinth apparatus are poorly known. The leaf lamina in the aquatic angiosperm Elodea canadensis consists of only two cell layers, with the abaxial cells developing as transfer cells. The present study investigated biochemical properties of wall ingrowths and associated plasmalemma in these cells. Leaves of Elodea were examined by light and electron microscopy and ATPase activity was localized cytochemically. Immunogold electron microscopy was employed to localize carbohydrate epitopes associated with major cell wall polysaccharides and glycoproteins. The plasmalemma associated with the wall labyrinth is strongly enriched in light-dependent ATPase activity. The wall ingrowths and an underlying wall layer share an LM11 epitope probably associated with glucuronoarabinoxylan and a CCRC-M7 epitope typically associated with rhamnogalacturonan I. No labelling was observed with LM10, an antibody that recognizes low-substituted and unsubstituted xylan, a polysaccharide consistently associated with secondary cell walls. The JIM5 and JIM7 epitopes, associated with homogalacturonan with different degrees of methylation, appear to be absent in the wall labyrinth but present in the rest of cell walls. The wall labyrinth apparatus of leaf transfer cells in Elodea is a specialized structure with distinctive biochemical properties. The high level of light-dependent ATPase activity in the plasmalemma lining the wall labyrinth is consistent with a formerly suggested role of leaf transfer cells in enhancing inorganic carbon inflow. The wall labyrinth is a part of the primary cell wall. The discovery that the wall ingrowths in Elodea have an antibody-binding pattern divergent, in part, from that of the rest of cell wall suggests that their carbohydrate composition is modulated in relation to transfer

  3. A study of the native cell wall structures of the marine alga Ventricaria ventricosa (Siphonocladales, Chlorophyceae) using atomic force microscopy.

    Science.gov (United States)

    Eslick, Enid M; Beilby, Mary J; Moon, Anthony R

    2014-04-01

    A substantial proportion of the architecture of the plant cell wall remains unknown with a few cell wall models being proposed. Moreover, even less is known about the green algal cell wall. Techniques that allow direct visualization of the cell wall in as near to its native state are of importance in unravelling the spatial arrangement of cell wall structures and hence in the development of cell wall models. Atomic force microscopy (AFM) was used to image the native cell wall of living cells of Ventricaria ventricosa (V. ventricosa) at high resolution under physiological conditions. The cell wall polymers were identified mainly qualitatively via their structural appearance. The cellulose microfibrils (CMFs) were easily recognizable and the imaging results indicate that the V. ventricosa cell wall has a cross-fibrillar structure throughout. We found the native wall to be abundant in matrix polysaccharides existing in different curing states. The soft phase matrix polysaccharides susceptible by the AFM scanning tip existed as a glutinous fibrillar meshwork, possibly incorporating both the pectic- and hemicellulosic-type substances. The hard phase matrix producing clearer images, revealed coiled fibrillar structures associated with CMFs, sometimes being resolved as globular structures by the AFM tip. The coiling fibrillar structures were also seen in the images of isolated cell wall fragments. The mucilaginous component of the wall was discernible from the gelatinous cell wall matrix as it formed microstructural domains over the surface. AFM has been successful in imaging the native cell wall and revealing novel findings such as the 'coiling fibrillar structures' and cell wall components which have previously not been seen, that is, the gelatinous matrix phase.

  4. Changes in inositol phosphates in wild carrot cells upon initiation of cell wall digestion

    International Nuclear Information System (INIS)

    Rincon, M.; Boss, W.F.

    1987-01-01

    Previous studies have shown that inositol trisphosphate (IP 3 ) stimulated 45 Ca +2 efflux from fusogenic carrot protoplasts and it was suggested that IP 3 may serve as a second messenger for the mobilization of intracellular Ca +2 in higher plant cells. To determine whether or not inositol phosphate metabolism changes in response to external stimuli, the cells were labeled with myo-[2- 3 H] inositol for 18 h and exposed to cell wall digestion enzymes, Driselase. The inositol phosphates were extracted with ice cold 10% TCA and separated by anion exchange chromatography. The radioactivity of the fraction that contained IP 3 increased 2-3.8 fold and that which contained inositol bisphosphate increased 1.9-2.6 fold within 1.5 min of exposure to Driselase. After 6 min, the radioactivity of both fractions increased 6-7.7 fold and an increase in inositol monophosphate was observed. These data indicate that inositol phosphate metabolism is stimulated by Driselase and suggest polyphosphoinositide hydrolysis occurs upon initiation of cell wall digestion

  5. The cell walls of green algae: a journey through evolution and diversity

    Directory of Open Access Journals (Sweden)

    David eDomozych

    2012-05-01

    Full Text Available The green algae represent a large group of morphologically diverse photosynthetic eukaryotes that occupy virtually every photic habitat on the planet. The extracellular coverings of green algae including cell walls are also diverse. A recent surge of research in green algal cell walls fueled by new emerging technologies has revealed new and critical insight concerning these coverings. For example, the late divergent taxa of the Charophycean Green Algae possess cell walls containing assemblages of polymers with notable similarity to the cellulose, pectins, hemicelluloses, arabinogalactan proteins, extensin and lignin present in embryophyte walls. Ulvophycean seaweeds have cell wall components whose most abundant fibrillar constituents may change from cellulose to β-mannans to β-xylans and during different life cycle phases. Likewise, these algae produce complex sulfated polysaccharides, arabinogalactan proteins and extensin. Chlorophycean green algae produce a wide array of walls ranging from cellulose-pectin complexes to ones made of hydroxyproline-rich glycoproteins. Larger and more detailed surveys of the green algal taxa including incorporation of emerging genomic and transcriptomic data are required in order to more fully resolve evolutionary trends within the green algae and in relationship with higher plants as well as potential applications of wall components in the food and pharmaceutical industries.

  6. The Cell Walls of Green Algae: A Journey through Evolution and Diversity.

    Science.gov (United States)

    Domozych, David S; Ciancia, Marina; Fangel, Jonatan U; Mikkelsen, Maria Dalgaard; Ulvskov, Peter; Willats, William G T

    2012-01-01

    The green algae represent a large group of morphologically diverse photosynthetic eukaryotes that occupy virtually every photic habitat on the planet. The extracellular coverings of green algae including cell walls are also diverse. A recent surge of research in green algal cell walls fueled by new emerging technologies has revealed new and critical insight concerning these coverings. For example, the late divergent taxa of the Charophycean green algae possess cell walls containing assemblages of polymers with notable similarity to the cellulose, pectins, hemicelluloses, arabinogalactan proteins (AGPs), extensin, and lignin present in embryophyte walls. Ulvophycean seaweeds have cell wall components whose most abundant fibrillar constituents may change from cellulose to β-mannans to β-xylans and during different life cycle phases. Likewise, these algae produce complex sulfated polysaccharides, AGPs, and extensin. Chlorophycean green algae produce a wide array of walls ranging from cellulose-pectin complexes to ones made of hydroxyproline-rich glycoproteins. Larger and more detailed surveys of the green algal taxa including incorporation of emerging genomic and transcriptomic data are required in order to more fully resolve evolutionary trends within the green algae and in relationship with higher plants as well as potential applications of wall components in the food and pharmaceutical industries.

  7. The changes of oil palm roots cell wall lipids during pathogenesis of Ganoderma boninense

    Science.gov (United States)

    Alexander, A.; Dayou, J.; Abdullah, S.; Chong, K. P.

    2017-07-01

    One of the first physical defences of plants against fungal infection is their cell wall. Interaction between combinations of metabolism enzymes known as the “weapons” of pathogen and the host cell wall probably determines the fate of possible invasion of the pathogen in the host. The present work aims to study the biochemical changes of cell wall lipids of oil palm roots and to determine novel information on root cell wall composition during pathogenesis of Ganoderma boninense by using Gas Chromatography Mass Spectrometry. Based on Total Ion Chromatogram analysis, 67 compounds were found more abundant in the roots infected with G. boninense compared to the healthy roots (60 compounds). Interestingly, nine new compounds were identified from the cell wall lipids of roots infected with G. boninense. These includes Cyclohexane, 1,2-dimethyl-, Methyl 2-hydroxy 16-methyl-heptadecanoate, 2-Propenoic acid, methyl ester, Methyl 9-oxohexacosanoate, 5-[(3,7,11,15-Tetramethylhexadecyl)oxy]thiophene-2carboxylic acid, Ergosta-5,7,22,24(28)-tetraen-3beta-ol, 7-Hydroxy-3',4'-methylenedioxyflavan, Glycine and (S)-4'-Hydroxy-4-methoxydalbergione, this may involve as response to pathogen invasion. This paper provides an original comparative lipidomic analysis of oil palm roots cell wall lipids in plant defence during pathogenesis of G. boninense.

  8. Neutrophil Attack Triggers Extracellular Trap-Dependent Candida Cell Wall Remodeling and Altered Immune Recognition.

    Directory of Open Access Journals (Sweden)

    Alex Hopke

    2016-05-01

    Full Text Available Pathogens hide immunogenic epitopes from the host to evade immunity, persist and cause infection. The opportunistic human fungal pathogen Candida albicans, which can cause fatal disease in immunocompromised patient populations, offers a good example as it masks the inflammatory epitope β-glucan in its cell wall from host recognition. It has been demonstrated previously that β-glucan becomes exposed during infection in vivo but the mechanism behind this exposure was unknown. Here, we show that this unmasking involves neutrophil extracellular trap (NET mediated attack, which triggers changes in fungal cell wall architecture that enhance immune recognition by the Dectin-1 β-glucan receptor in vitro. Furthermore, using a mouse model of disseminated candidiasis, we demonstrate the requirement for neutrophils in triggering these fungal cell wall changes in vivo. Importantly, we found that fungal epitope unmasking requires an active fungal response in addition to the stimulus provided by neutrophil attack. NET-mediated damage initiates fungal MAP kinase-driven responses, particularly by Hog1, that dynamically relocalize cell wall remodeling machinery including Chs3, Phr1 and Sur7. Neutrophil-initiated cell wall disruptions augment some macrophage cytokine responses to attacked fungi. This work provides insight into host-pathogen interactions during disseminated candidiasis, including valuable information about how the C. albicans cell wall responds to the biotic stress of immune attack. Our results highlight the important but underappreciated concept that pattern recognition during infection is dynamic and depends on the host-pathogen dialog.

  9. Carbohydrate-related genes and cell wall biosynthesis in vascular tissues of loblolly pine (Pinus taeda).

    Science.gov (United States)

    Nairn, Campbell J; Lennon, Denise M; Wood-Jones, Alicia; Nairn, Alison V; Dean, Jeffrey F D

    2008-07-01

    Loblolly pine (Pinus taeda L.), the most widely planted tree species in the United States, is an important source of wood and wood fibers for a multitude of consumer products. Wood fibers are primarily composed of secondary cell walls, and cellulose, hemicelluloses and lignin are major components of wood. Fiber morphology and cell wall composition are important determinants of wood properties. We used comparative genomics to identify putative genes for cellulose and hemicellulose synthesis in loblolly pine that are homologous to genes implicated in cell wall synthesis in angiosperms. Sequences encoding putative secondary cell wall cellulose synthase genes, cellulose synthase-like genes, a membrane-bound endoglucanase gene, a sucrose synthase gene, a UDP-glucose pyrophosphorylase gene and GDP-mannose pyrophosphorylase genes were identified in expressed sequence tag (EST) collections from loblolly pine. Full-length coding sequences were obtained from cDNA clones isolated from a library constructed from developing xylem. Phylogenetic relationships between the genes from loblolly pine and angiosperm taxa were examined and transcriptional profiling in vascular tissues was conducted by real-time quantitative, reverse transcriptase-polymerase chain reaction. The putative cell wall synthesis genes were expressed at high levels in vascular tissues and a subset was differentially regulated in xylem and phloem tissues. Inferred phylogenetic relationships and expression patterns for the genes from loblolly pine were consistent with roles in synthesis of complex carbohydrates of the cell wall. These studies suggest functional conservation of homologous wood formation genes in gymnosperm and angiosperm taxa.

  10. Plant cell wall sugars: sweeteners for a bio-based economy.

    Science.gov (United States)

    Van de Wouwer, Dorien; Boerjan, Wout; Vanholme, Bartel

    2018-02-12

    Global warming and the consequent climate change is one of the major environmental challenges we are facing today. The driving force behind the rise in temperature is our fossil-based economy, which releases massive amounts of the greenhouse gas carbon dioxide into the atmosphere. In order to reduce greenhouse gas emission, we need to scale down our dependency on fossil resources, implying that we need other sources for energy and chemicals to feed our economy. Here, plants have an important role to play; by means of photosynthesis, plants capture solar energy to split water and fix carbon derived from atmospheric carbon dioxide. A significant fraction of the fixed carbon ends up as polysaccharides in the plant cell wall. Fermentable sugars derived from cell wall polysaccharides form an ideal carbon source for the production of bio-platform molecules. However, a major limiting factor in the use of plant biomass as feedstock for the bio-based economy is the complexity of the plant cell wall and its recalcitrance towards deconstruction. To facilitate the release of fermentable sugars during downstream biomass processing, the composition and structure of the cell wall can be engineered. Different strategies to reduce cell wall recalcitrance will be described in this review. The ultimate goal is to obtain a tailor-made biomass, derived from plants with a cell wall optimized for particular industrial or agricultural applications, without affecting plant growth and development. This article is protected by copyright. All rights reserved.

  11. Characterization of xylan in the early stages of secondary cell wall formation in tobacco bright yellow-2 cells.

    Science.gov (United States)

    Ishii, Tadashi; Matsuoka, Keita; Ono, Hiroshi; Ohnishi-Kameyama, Mayumi; Yaoi, Katsuro; Nakano, Yoshimi; Ohtani, Misato; Demura, Taku; Iwai, Hiroaki; Satoh, Shinobu

    2017-11-15

    The major polysaccharides present in the primary and secondary walls surrounding plant cells have been well characterized. However, our knowledge of the early stages of secondary wall formation is limited. To address this, cell walls were isolated from differentiating xylem vessel elements of tobacco bright yellow-2 (BY-2) cells induced by VASCULAR-RELATED NAC-DOMAIN7 (VND7). The walls of induced VND7-VP16-GR BY-2 cells consisted of cellulose, pectic polysaccharides, hemicelluloses, and lignin, and contained more xylan and cellulose compared with non-transformed BY-2 and uninduced VND7-VP16-GR BY-2 cells. A reducing end sequence of xylan containing rhamnose and galaturonic acid- residues is present in the walls of induced, uninduced, and non-transformed BY-2 cells. Glucuronic acid residues in xylan from walls of induced cells are O-methylated, while those of xylan in non-transformed BY-2 and uninduced cells are not. Our results show that xylan changes in chemical structure and amounts during the early stages of xylem differentiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. MALDI-TOF MS and CE-LIF Fingerprinting of Plant Cell Wall Polysaccharide Digests as a Screening Tool for Arabidopsis Cell Wall Mutants

    NARCIS (Netherlands)

    Westphal, Y.; Schols, H.A.; Voragen, A.G.J.; Gruppen, H.

    2010-01-01

    Cell wall materials derived from leaves and hypocotyls of Arabidopsis mutant and wild type plants have been incubated with a mixture of pure and well-defined pectinases, hemicellulases, and cellulases. The resulting oligosaccharides have been subjected to MALDI-TOF MS and CE-LIF analysis. MALDI-TOF

  13. Proteomic signatures and aberrations of mouse embryonic stem cells containing a single human chromosome 21 in neuronal differentiation: an in vitro model of Down syndrome.

    Science.gov (United States)

    Kadota, M; Nishigaki, R; Wang, C C; Toda, T; Shirayoshi, Y; Inoue, T; Gojobori, T; Ikeo, K; Rogers, M S; Oshimura, M

    2004-01-01

    Neurodegeneration in fetal development of Down syndrome (DS) patients is proposed to result in apparent neuropathological abnormalities and to contribute to the phenotypic characteristics of mental retardation and premature development of Alzheimer disease. In order to identify the aberrant and specific genes involved in the early differentiation of DS neurons, we have utilized an in vitro neuronal differentiation system of mouse ES cells containing a single human chromosome 21 (TT2F/hChr21) with TT2F parental ES cells as a control. The paired protein extracts from TT2F and TT2F/hChr21 cells at several stages of neuronal differentiation were subjected to two-dimensional polyacrylamide gel electrophoresis protein separation followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry to identify the proteins differentially expressed between TT2F and TT2F/hChr21 cells. We provide here a novel set of specific gene products altered in early differentiating DS neuronal cells, which differs from that identified in adult or fetal brain with DS. The aberrant protein expression in early differentiating neurons, due to the hChr21 gene dosage effects or chromosomal imbalance, may affect neuronal outgrowth, proliferation and differentiation, producing developmental abnormalities in neural patterning, which eventually leads to formation of a suboptimal functioning neuronal network in DS.

  14. Candida and candidiasis: the cell wall as a potential molecular target for antifungal therapy.

    Science.gov (United States)

    Gozalbo, Daniel; Roig, Patricia; Villamón, Eva; Gil, María Luisa

    2004-06-01

    The fungal species Candida albicans is an opportunistic pathogen, which causes serious infections in humans, particularly in immunocompromised patients. Depending on the underlying host defect, C. albicans causes a variety of infections, ranging from superficial mucocutaneous candidiasis to life-threatening disseminated infections. Both the limited spectrum of antifungal drugs currently in clinical use and the emergence of resistances make necessary the development of new effective antifungal drugs with minimal side effects; however, such a research is limited by the small number of specific target sites identified to date. The cell wall is a fungal specific dynamic structure essential to almost every aspect of the biology and pathogenicity of C. albicans. Its structure confers physical protection and shape to fungal cells, and as the most external part of the fungus, the cell wall mediates the interaction with the host, including adhesion to host tissues and modulation of the host anti-Candida immune response. Consequently, the fungal cell wall can be considered as a suitable target for development of new antifungal compounds. Therefore two distinct types of potential cell wall-related targets can be envisaged, according to their mode of action in inhibiting infection: (i) inhibition of cell wall biogenesis, which may impair cell wall integrity and thus cell viability, and (ii) modification of host-fungus interactions by inhibiting or blocking putative virulence factors, which may impair host colonization and progress of the infectious process. Antibodies specific to cell wall antigens may protect against infection by a variety of mechanisms and may evolve into save antifungal agents.

  15. Tubulin perturbation leads to unexpected cell wall modifications and affects stomatal behaviour in Populus.

    Science.gov (United States)

    Swamy, Prashant S; Hu, Hao; Pattathil, Sivakumar; Maloney, Victoria J; Xiao, Hui; Xue, Liang-Jiao; Chung, Jeng-Der; Johnson, Virgil E; Zhu, Yingying; Peter, Gary F; Hahn, Michael G; Mansfield, Shawn D; Harding, Scott A; Tsai, Chung-Jui

    2015-10-01

    Cortical microtubules are integral to plant morphogenesis, cell wall synthesis, and stomatal behaviour, presumably by governing cellulose microfibril orientation. Genetic manipulation of tubulins often leads to abnormal plant development, making it difficult to probe additional roles of cortical microtubules in cell wall biogenesis. Here, it is shown that expressing post-translational C-terminal modification mimics of α-tubulin altered cell wall characteristics and guard cell dynamics in transgenic Populus tremula x alba that otherwise appear normal. 35S promoter-driven transgene expression was high in leaves but unusually low in xylem, suggesting high levels of tubulin transgene expression were not tolerated in wood-forming tissues during regeneration of transformants. Cellulose, hemicellulose, and lignin contents were unaffected in transgenic wood, but expression of cell wall-modifying enzymes, and extractability of lignin-bound pectin and xylan polysaccharides were increased in developing xylem. The results suggest that pectin and xylan polysaccharides deposited early during cell wall biogenesis are more sensitive to subtle tubulin perturbation than cellulose and matrix polysaccharides deposited later. Tubulin perturbation also affected guard cell behaviour, delaying drought-induced stomatal closure as well as light-induced stomatal opening in leaves. Pectins have been shown to confer cell wall flexibility critical for reversible stomatal movement, and results presented here are consistent with microtubule involvement in this process. Taken together, the data show the value of growth-compatible tubulin perturbations for discerning microtubule functions, and add to the growing body of evidence for microtubule involvement in non-cellulosic polysaccharide assembly during cell wall biogenesis. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. Evidence for land plant cell wall biosynthetic mechanisms in charophyte green algae

    Science.gov (United States)

    Mikkelsen, Maria D.; Harholt, Jesper; Ulvskov, Peter; Johansen, Ida E.; Fangel, Jonatan U.; Doblin, Monika S.; Bacic, Antony; Willats, William G. T.

    2014-01-01

    Background and Aims The charophyte green algae (CGA) are thought to be the closest living relatives to the land plants, and ancestral CGA were unique in giving rise to the land plant lineage. The cell wall has been suggested to be a defining structure that enabled the green algal ancestor to colonize land. These cell walls provide support and protection, are a source of signalling molecules, and provide developmental cues for cell differentiation and elongation. The cell wall of land plants is a highly complex fibre composite, characterized by cellulose cross-linked by non-cellulosic polysaccharides, such as xyloglucan, embedded in a matrix of pectic polysaccharides. How the land plant cell wall evolved is currently unknown: early-divergent chlorophyte and prasinophyte algae genomes contain a low number of glycosyl transferases (GTs), while land plants contain hundreds. The number of GTs in CGA is currently unknown, as no genomes are available, so this study sought to give insight into the evolution of the biosynthetic machinery of CGA through an analysis of available transcriptomes. Methods Available CGA transcriptomes were mined for cell wall biosynthesis GTs and compared with GTs characterized in land plants. In addition, gene cloning was employed in two cases to answer important evolutionary questions. Key Results Genetic evidence was obtained indicating that many of the most important core cell wall polysaccharides have their evolutionary origins in the CGA, including cellulose, mannan, xyloglucan, xylan and pectin, as well as arabino-galactan protein. Moreover, two putative cellulose synthase-like D family genes (CSLDs) from the CGA species Coleochaete orbicularis and a fragment of a putative CSLA/K-like sequence from a CGA Spirogyra species were cloned, providing the first evidence that all the cellulose synthase/-like genes present in early-divergent land plants were already present in CGA. Conclusions The results provide new insights into the evolution of

  17. Induction of chromosomal aberrations in mouse zygotes by acrylamide treatment of male germ cells and their correlation with dominant lethality and heritable translocations

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, F.; Lowe, X.; Wyrobek, A.J. [Lawrence Livermore National Lab., CA (United States); Bishop, J. [National Institute of Environmental Health Sciences, Research Triangle Park, NC (United States)

    1997-12-31

    The objectives of this research were: (1) to investigate the time course of the cytogenetic defects induced by acrylamide (AA) treatment (5 x 50 mg/kg) of male germ cells in first-cleavage zygote metaphases using PAINT/DAPI analysis, and (2) to characterize the correlation between chromosomal aberrations at first cleavage, dominant lethality, and heritable translocations. PAINT/DAPI analysis employs multicolor fluorescence in situ hybridization painting plus DAPI staining to detect both stable and unstable chromosomal aberrations at first-cleavage metaphase of the zygote. High levels of chromosomally defective zygotes were detected after mating at all postmeiotic stages (20-190-fold, P < 0.001). Early spermatozoa (6.5 d post-treatment) were the most sensitive, with 76% of the zygotes carrying cytogenetic defects. A significant 10-fold increase was also detected 27.5 d post-treatment, indicating that AA had a cytogenetic effect on meiotic stages. PAINT/DAPI analysis revealed that: (1) AA-induced chromosomal breaks occurred at random, and (2) the frequencies of symmetrical and asymmetrical exchanges were similar at all mating days, except 9.5 d after AA treatment, where significantly (P < 0.02) more asymmetrical aberrations were found. 33 refs., 5 figs., 4 tabs.

  18. Mitochondrial-Associated Cell Death Mechanisms Are Reset to an Embryonic-Like State in Aged Donor-Derived iPS Cells Harboring Chromosomal Aberrations

    Science.gov (United States)

    Prigione, Alessandro; Hossini, Amir M.; Lichtner, Björn; Serin, Akdes; Fauler, Beatrix; Megges, Matthias; Lurz, Rudi; Lehrach, Hans; Zouboulis, Christos C.

    2011-01-01

    Somatic cells reprogrammed into induced pluripotent stem cells (iPSCs) acquire features of human embryonic stem cells (hESCs) and thus represent a promising source for cellular therapy of debilitating diseases, such as age-related disorders. However, reprogrammed cell lines have been found to harbor various genomic alterations. In addition, we recently discovered that the mitochondrial DNA of human fibroblasts also undergoes random mutational events upon reprogramming. Aged somatic cells might possess high susceptibility to nuclear and mitochondrial genome instability. Hence, concerns over the oncogenic potential of reprogrammed cells due to the lack of genomic integrity may hinder the applicability of iPSC-based therapies for age-associated conditions. Here, we investigated whether aged reprogrammed cells harboring chromosomal abnormalities show resistance to apoptotic cell death or mitochondrial-associated oxidative stress, both hallmarks of cancer transformation. Four iPSC lines were generated from dermal fibroblasts derived from an 84-year-old woman, representing the oldest human donor so far reprogrammed to pluripotency. Despite the presence of karyotype aberrations, all aged-iPSCs were able to differentiate into neurons, re-establish telomerase activity, and reconfigure mitochondrial ultra-structure and functionality to a hESC-like state. Importantly, aged-iPSCs exhibited high sensitivity to drug-induced apoptosis and low levels of oxidative stress and DNA damage, in a similar fashion as iPSCs derived from young donors and hESCs. Thus, the occurrence of chromosomal abnormalities within aged reprogrammed cells might not be sufficient to over-ride the cellular surveillance machinery and induce malignant transformation through the alteration of mitochondrial-associated cell death. Taken together, we unveiled that cellular reprogramming is capable of reversing aging-related features in somatic cells from a very old subject, despite the presence of genomic

  19. Mitochondrial-associated cell death mechanisms are reset to an embryonic-like state in aged donor-derived iPS cells harboring chromosomal aberrations.

    Directory of Open Access Journals (Sweden)

    Alessandro Prigione

    Full Text Available Somatic cells reprogrammed into induced pluripotent stem cells (iPSCs acquire features of human embryonic stem cells (hESCs and thus represent a promising source for cellular therapy of debilitating diseases, such as age-related disorders. However, reprogrammed cell lines have been found to harbor various genomic alterations. In addition, we recently discovered that the mitochondrial DNA of human fibroblasts also undergoes random mutational events upon reprogramming. Aged somatic cells might possess high susceptibility to nuclear and mitochondrial genome instability. Hence, concerns over the oncogenic potential of reprogrammed cells due to the lack of genomic integrity may hinder the applicability of iPSC-based therapies for age-associated conditions. Here, we investigated whether aged reprogrammed cells harboring chromosomal abnormalities show resistance to apoptotic cell death or mitochondrial-associated oxidative stress, both hallmarks of cancer transformation. Four iPSC lines were generated from dermal fibroblasts derived from an 84-year-old woman, representing the oldest human donor so far reprogrammed to pluripotency. Despite the presence of karyotype aberrations, all aged-iPSCs were able to differentiate into neurons, re-establish telomerase activity, and reconfigure mitochondrial ultra-structure and functionality to a hESC-like state. Importantly, aged-iPSCs exhibited high sensitivity to drug-induced apoptosis and low levels of oxidative stress and DNA damage, in a similar fashion as iPSCs derived from young donors and hESCs. Thus, the occurrence of chromosomal abnormalities within aged reprogrammed cells might not be sufficient to over-ride the cellular surveillance machinery and induce malignant transformation through the alteration of mitochondrial-associated cell death. Taken together, we unveiled that cellular reprogramming is capable of reversing aging-related features in somatic cells from a very old subject, despite the presence

  20. Chromosome Aberrations by Heavy Ions

    Science.gov (United States)

    Ballarini, Francesca; Ottolenghi, Andrea

    It is well known that mammalian cells exposed to ionizing radiation can show different types of chromosome aberrations (CAs) including dicentrics, translocations, rings, deletions and complex exchanges. Chromosome aberrations are a particularly relevant endpoint in radiobiology, because they play a fundamental role in the pathways leading either to cell death, or to cell conversion to malignancy. In particular, reciprocal translocations involving pairs of specific genes are strongly correlated (and probably also causally-related) with specific tumour types; a typical example is the BCR-ABL translocation for Chronic Myeloid Leukaemia. Furthermore, aberrations can be used for applications in biodosimetry and more generally as biomarkers of exposure and risk, that is the case for cancer patients monitored during Carbon-ion therapy and astronauts exposed to space radiation. Indeed hadron therapy and astronauts' exposure to space radiation represent two of the few scenarios where human beings can be exposed to heavy ions. After a brief introduction on the main general features of chromosome aberrations, in this work we will address key aspects of the current knowledge on chromosome aberration induction, both from an experimental and from a theoretical point of view. More specifically, in vitro data will be summarized and discussed, outlining important issues such as the role of interphase death/mitotic delay and that of complex-exchange scoring. Some available in vivo data on cancer patients and astronauts will be also reported, together with possible interpretation problems. Finally, two of the few available models of chromosome aberration induction by ionizing radiation (including heavy ions) will be described and compared, focusing on the different assumptions adopted by the authors and on how these models can deal with heavy ions.

  1. Analysis of the cell wall and lipopolysaccharide of Spirillum serpens.

    Science.gov (United States)

    Chester, I R; Murray, R G

    1975-12-01

    Isolated walls of Spirillum serpens VHA contained lipid, lipopolysaccharide, and protein in amounts similar to those of other gram-negative organisms. The loosely bound lipids consisted mainly of phosphatidylethanolamine, lyso-phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. Lipopolysaccharide was tightly bound to the wall and could only be removed in a substantial amount after digestion of the wall with Pronase. The lipopolysaccharide contained L-glycero-D-mannoheptose, rhamnose, glucosamine, ethanolamine, and phosphate in common with many of the lipopolysaccharides isolated from the Enterobacteriaceae. However, 2-keto-3-deoxyoctonic acid was not detected. Several unidentified sugars were present. The fatty acid composition resembled that found in lipopolysaccharides isolated from various pseudomonads. Two major regions were identified in the polysaccharide moiety, one apparently corresponding to the core polysaccharide and the other corresponding to the side-chain polysaccharide as in enterobacterial and pseudomonad lipopolysaccharides. The side chains were obtained as low-molecular-weight material and their structure was partially elucidated by the isolation and partial characterization of N-acetylglucosaminyl-(1 leads to 4)-rhamnose.

  2. N-acetylglucosamine affects Cryptococcus neoformans cell-wall composition and melanin architecture.

    Science.gov (United States)

    Camacho, Emma; Chrissian, Christine; Cordero, Radames J B; Liporagi-Lopes, Livia; Stark, Ruth E; Casadevall, Arturo

    2017-11-01

    Cryptococcus neoformans is an environmental fungus that belongs to the phylum Basidiomycetes and is a major pathogen in immunocompromised patients. The ability of C. neoformans to produce melanin pigments represents its second most important virulence factor, after the presence of a polysaccharide capsule. Both the capsule and melanin are closely associated with the fungal cell wall, a complex structure that is essential for maintaining cell morphology and viability under conditions of stress. The amino sugar N-acetylglucosamine (GlcNAc) is a key constituent of the cell-wall chitin and is used for both N-linked glycosylation and GPI anchor synthesis. Recent studies have suggested additional roles for GlcNAc as an activator and mediator of cellular signalling in fungal and plant cells. Furthermore, chitin and chitosan polysaccharides interact with melanin pigments in the cell wall and have been found to be essential for melanization. Despite the importance of melanin, its molecular structure remains unresolved; however, we previously obtained critical insights using advanced nuclear magnetic resonance (NMR) and imaging techniques. In this study, we investigated the effect of GlcNAc supplementation on cryptococcal cell-wall composition and melanization. C. neoformans was able to metabolize GlcNAc as a sole source of carbon and nitrogen, indicating a capacity to use a component of a highly abundant polymer in the biospherenutritionally. C. neoformans cells grown with GlcNAc manifested changes in the chitosan cell-wall content, cell-wall thickness and capsule size. Supplementing cultures with isotopically 15 N-labelled GlcNAc demonstrated that the exogenous monomer serves as a building block for chitin/chitosan and is incorporated into the cell wall. The altered chitin-to-chitosan ratio had no negative effects on the mother-daughter cell separation; growth with GlcNAc affected the fungal cell-wall scaffold, resulting in increased melanin deposition and assembly. In

  3. Simulations of DSB Yields and Radiation-induced Chromosomal Aberrations in Human Cells Based on the Stochastic Track Structure iIduced by HZE Particles

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; George, Kerry; Wu, Honglu

    2014-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a new particle track and DNA damage model, in which the particle stochastic track structure is combined with the random walk (RW) structure of chromosomes in a cell nucleus. The motivation for this effort stems from the fact that the model with the RW chromosomes, NASARTI (NASA radiation track image) previously relied on amorphous track structure, while the stochastic track structure model RITRACKS (Relativistic Ion Tracks) was focused on more microscopic targets than the entire genome. We have combined chromosomes simulated by RWs with stochastic track structure, which uses nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS in a voxelized space. The new simulations produce the number of DSBs as function of dose and particle fluence for high-energy particles, including iron, carbon and protons, using voxels of 20 nm dimension. The combined model also calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The joined computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The joined model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation. We found that the main advantage of the joined model is our ability to simulate small doses: 0.05-0.5 Gy. At such low doses, the stochastic track structure proved to be indispensable, as the action of individual delta-rays becomes more important.

  4. Simulations of DSB Yields and Radiation-induced Chromosomal Aberrations in Human Cells Based on the Stochastic Track Structure Induced by HZE Particles

    Science.gov (United States)

    Ponomarev, Artem; Plante, Ianik; George, Kerry; Wu, Honglu

    2014-01-01

    The formation of double-strand breaks (DSBs) and chromosomal aberrations (CAs) is of great importance in radiation research and, specifically, in space applications. We are presenting a new particle track and DNA damage model, in which the particle stochastic track structure is combined with the random walk (RW) structure of chromosomes in a cell nucleus. The motivation for this effort stems from the fact that the model with the RW chromosomes, NASARTI (NASA radiation track image) previously relied on amorphous track structure, while the stochastic track structure model RITRACKS (Relativistic Ion Tracks) was focused on more microscopic targets than the entire genome. We have combined chromosomes simulated by RWs with stochastic track structure, which uses nanoscopic dose calculations performed with the Monte-Carlo simulation by RITRACKS in a voxelized space. The new simulations produce the number of DSBs as function of dose and particle fluence for high-energy particles, including iron, carbon and protons, using voxels of 20 nm dimension. The combined model also calculates yields of radiation-induced CAs and unrejoined chromosome breaks in normal and repair deficient cells. The joined computational model is calibrated using the relative frequencies and distributions of chromosomal aberrations reported in the literature. The model considers fractionated deposition of energy to approximate dose rates of the space flight environment. The joined model also predicts of the yields and sizes of translocations, dicentrics, rings, and more complex-type aberrations formed in the G0/G1 cell cycle phase during the first cell division after irradiation. We found that the main advantage of the joined model is our ability to simulate small doses: 0.05-0.5 Gy. At such low doses, the stochastic track structure proved to be indispensable, as the action of individual delta-rays becomes more important.

  5. Relationship of DNA repair to chromosome aberrations, sister-chromatid exchanges and survival during liquid-holding recovery in X-irradiated mammalian cells

    International Nuclear Information System (INIS)

    Fornace, A.J. Jr.; Nagasawa, H.; Little, J.B.

    1980-01-01

    The repair of X-ray-induced DNA single strand breaks and DNA-protein cross-links was investigated in stationary phase, contact-inhibited mouse cells by the alkaline-elution technique. Approx. 90% of X-ray-induced single strand breaks were rejoined during the first hour of repair, whereas most of the remaining breaks were rejoined more slowly during the next 5 h. At early repair times, the number of residual non-rejoined sungle strand breaks was approx. proportional to the X-ray dose. DNA-protein cross-links were removed at a slower rate (Tsub(1/2) approx. 10-12 h). Cells were held in stationary growth for various periods of time after irradiation before subculture at low density to score for colony survival (potentially lethal damage repair), chromosome aberrations in the first mitosis, and sister-chromatid exchanges in the second mitosis. Both cell killing and the frequency of chromosome aberrations decreased during the first several hours of recovery, reaching a minimum level by 6 h; this decrease correlated temporally with the repair of the slowly rejoining DNA-strand breaks. Relatively few sister-chromatid exchanges were observed when the cells were subcultured immediately after X-ray. The exchange frequency rose to maximum levels after a 4-h recovery interval, and returned to control levels after 12 h of recovery. The possible relationship of DNA repair to these changes in survival, chromosome aberrations, and sister-chromatid exchanges during liquid-holding recovery is discussed. (orig.)

  6. Inorganic polyphosphate occurs in the cell wall of Chlamydomonas reinhardtii and accumulates during cytokinesis

    Directory of Open Access Journals (Sweden)

    Freimoser Florian M

    2007-09-01

    Full Text Available Abstract Background Inorganic polyphosphate (poly P, linear chains of phosphate residues linked by energy rich phosphoanhydride bonds, is found in every cell and organelle and is abundant in algae. Depending on its localization and concentration, poly P is involved in various biological functions. It serves, for example, as a phosphate store and buffer against alkali, is involved in energy metabolism and regulates the activity of enzymes. Bacteria defective in poly P synthesis are impaired in biofilm development, motility and pathogenicity. PolyP has also been found in fungal cell walls and bacterial envelopes, but has so far not been measured directly or stained specifically in the cell wall of any plant or alga. Results Here, we demonstrate the presence of poly P in the cell wall of Chlamydomonas reinhardtii by staining with specific poly P binding proteins. The specificity of the poly P signal was verified by various competition experiments, by staining with different poly P binding proteins and by correlation with biochemical quantification. Microscopical investigation at different time-points during growth revealed fluctuations of the poly P signal synchronous with the cell cycle: The poly P staining peaked during late cytokinesis and was independent of the high intracellular poly P content, which fluctuated only slightly during the cell cycle. Conclusion The presented staining method provides a specific and sensitive tool for the study of poly P in the extracellular matrices of algae and could be used to describe the dynamic behaviour of cell wall poly P during the cell cycle. We assume that cell wall poly P and intracellular poly P are regulated by distinct mechanisms and it is suggested that cell wall bound poly P might have important protective functions against toxic compounds or pathogens during cytokinesis, when cells are more vulnerable.

  7. The best time of cytotoxicity for extracted cell wall from Lactobacillus casei and paracasei in K562 cell line

    Directory of Open Access Journals (Sweden)

    Riki M

    2013-02-01

    Full Text Available Background: The aim of this study was to evaluate the effect of extracted cell walls from Lactobacillus casei and Lactobacillus paracasei as probiotic bacteria (isolated from common carp intestine on K562 and the role of cell concentration on the results of MTT [3-(4,5-Dimethylthiazol-2-yl2,5- Diphenyl tetrazolium Bromide] test.Methods: For this purpose, bacteria were cultured in specific medium (MRS broth at anaerobic condition for 24-48 hour. After incubation period culture medium was centri-fuged, then the cells were washed twice with PBS buffer to remove additional medium. Finally, collected bacterial cell disrupted by Sonication and cell walls were separated from other components by centrifugation. After that, different concentrations of cell walls (500, 1000, 2000 and 4000 µg/ml were prepared in RPMI medium for each bacteria, separately. Then anticancer properties of the cell walls were determined in vitro at 12, 24, 48 and 72 h, also the effect of K562 concentration was assayed with MTT technique.Results: The results showed extracted cell wall from both probiotic statistically (P=0.098 have anti turmeric properties in K562 and their properties will arise in relation with concentration. As well as, we found that the number of cell had not any affect on the result of MTT assay.Conclusion: We conclude that the cytotoxicity property of extracted cell wall is related in the type of bacteria, but this anticancer property would warrant further study on the clinical application of extracted cell wall.

  8. MECHANISM OF ACTION OF ANTIBIOTICS WHICH INHIBIT SYNTHESIS OF BACTERIAL CELL WALL

    Directory of Open Access Journals (Sweden)

    Indira Mujezinović

    2013-03-01

    Full Text Available Bacterial cell possess a cell wall, which is a main difference from mammalian cells. Its basic function is to provide the strength of bacteria, keeps its shape and provides an unusually high internal osmotic pressure. Synthesis of (construction of bacterial cell wall occurs in at least three phases. All of these three phases can be influence by a variety of antibiotics in way to inhibit its synthesis. The most important drugs that act in this manner are ß-lactam antibiotics (penicillins, cephalosporins, cephamycins and other ß-lactams. They interfere with the synthesis of the bacterial cell wall peptidoglycan. After attachment to penicillin binding proteins (PBP on bacteria, they inhibit the transpeptidation enzyme that cross-links the peptide chain attached to the backbone of the peptidoglycan. The final bactericidal event is the inactivation of an inhibitor of autolytic enzymes in the cell wall, wich leads to lysis of the bacteria. Vancomycin inhibits the release of the building block unit from the carrier, thus preventing its addition to the growing end of the peptidoglycan. Cycloserine, which is a structural analogue of D-alanine, prevents the addition of the two terminal alanine residue to the initial tripeptide side-chain on N-acetylmuramic acid by competitive inhibition. Bacitracin interferes with the regeneration of the lipid carrier by blocking its dephosphorylation. Key words: bacterial cell wall, paptidoglycan, antibiotics, ß-lactams

  9. Interactions of the cell-wall glycopolymers of lactic acid bacteria with their bacteriophages

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    Marie-Pierre eChapot-Chartier

    2014-05-01

    Full Text Available Lactic acid bacteria (LAB are Gram positive bacteria widely used in the production of fermented food in particular cheese and yoghurts. Bacteriophage infections during fermentation processes have been for many years a major industrial concern and have stimulated numerous research efforts. Better understanding of the molecular mechanisms of bacteriophage interactions with their host bacteria is required for the development of efficient strategies to fight against infections. The bacterial cell wall plays key roles in these interactions. First, bacteriophages must adsorb at the bacterial surface through specific interactions with receptors that are cell wall components. At next step, phages must overcome the barrier constituted by cell wall peptidoglycan to inject DNA inside bacterial cell. Also at the end of the infection cycle, phages synthesize endolysins able to hydrolyze peptidoglycan and lyse bacterial cells to release phage progeny. In the last decade, concomitant development of genomics and structural analysis of cell wall components allowed considerable advances in the knowledge of their structure and function in several model LAB. Here, we describe the present knowledge on the structure of the cell wall glycopolymers of the best characterized LAB emphasizing their structural variations and we present the available data regarding their role in bacteria-phage specific interactions at the different steps of the infection cycle.

  10. Differential Actions of Chlorhexidine on the Cell Wall of Bacillus subtilis and Escherichia coli

    Science.gov (United States)

    Cheung, Hon-Yeung; Wong, Matthew Man-Kin; Cheung, Sau-Ha; Liang, Longman Yimin; Lam, Yun-Wah; Chiu, Sung-Kay

    2012-01-01

    Chlorhexidine is a chlorinated phenolic disinfectant used commonly in mouthwash for its action against bacteria. However, a comparative study of the action of chlorhexidine on the cell morphology of Gram-positive and Gram-negative bacteria is lacking. In this study, the actions of chlorhexidine on the cell morphology were identified with the aids of electron microscopy. After exposure to chlorhexidine, numerous spots of indentation on the cell wall were found in both Bacillus subtilis and Escherichia coli. The number of indentation spots increased with time of incubation and increasing chlorhexidine concentration. Interestingly, the dented spots found in B. subtilis appeared mainly at the hemispherical caps of the cells, while in E. coli the dented spots were found all over the cells. After being exposed to chlorhexidine for a prolonged period, leakage of cellular contents and subsequent ghost cells were observed, especially from B subtilis. By using 2-D gel/MS-MS analysis, five proteins related to purine nucleoside interconversion and metabolism were preferentially induced in the cell wall of E. coli, while three proteins related to stress response and four others in amino acid biosynthesis were up-regulated in the cell wall materials of B. subtilis. The localized morphological damages together with the biochemical and protein analysis of the chlorhexidine-treated cells suggest that chlorhexidine may act on the differentially distributed lipids in the cell membranes/wall of B. subtilis and E. coli. PMID:22606280

  11. Phyllanthus emblica Fruit Extract Activates Spindle Assembly Checkpoint, Prevents Mitotic Aberrations and Genomic Instability in Human Colon Epithelial NCM460 Cells.

    Science.gov (United States)

    Guo, Xihan; Wang, Xu

    2016-09-03

    The fruit of Phyllanthus emblica Linn. (PE) has been widely consumed as a functional food and folk medicine in Southeast Asia due to its remarkable nutritional and pharmacological effects. Previous research showed PE delays mitotic progress and increases genomic instability (GIN) in human colorectal cancer cells. This study aimed to investigate the similar effects of PE by the biomarkers related to spindle assembly checkpoint (SAC), mitotic aberrations and GIN in human NCM460 normal colon epithelial cells. Cells were treated with PE and harvested differently according to the biomarkers observed. Frequencies of micronuclei (MN), nucleoplasmic bridge (NPB) and nuclear bud (NB) in cytokinesis-block micronucleus assay were used as indicators of GIN. Mitotic aberrations were assessed by the biomarkers of chromosome misalignment, multipolar division, chromosome lagging and chromatin bridge. SAC activity was determined by anaphase-to- metaphase ratio (AMR) and the expression of core SAC gene budding uninhibited by benzimidazoles related 1 (BubR1). Compared with the control, PE-treated cells showed (1) decreased incidences of MN, NPB and NB (p genomic damages partially by enhancing the function of SAC.

  12. 2009 Plant Cell Walls Gordon Research Conference-August 2-7,2009

    Energy Technology Data Exchange (ETDEWEB)

    Mohnen, Debra [Univ. of Georgia, Athens, GA (United States)

    2009-08-07

    Plant cell walls are a complex cellular compartment essential for plant growth, development and response to biotic and abiotic stress and a major biological resource for meeting our future bioenergy and natural product needs. The goal of the 2009 Plant Cell Walls Gordon Research Conference is to summarize and critically evaluate the current level of understanding of the structure, synthesis and function of the whole plant extracellular matrix, including the polysaccharides, proteins, lignin and waxes that comprise the wall, and the enzymes and regulatory proteins that drive wall synthesis and modification. Innovative techniques to study how both primary and secondary wall polymers are formed and modified throughout plant growth will be emphasized, including rapid advances taking place in the use of anti-wall antibodies and carbohydrate binding proteins, comparative and evolutionary wall genomics, and the use of mutants and natural variants to understand and identify wall structure-function relationships. Discussions of essential research advances needed to push the field forward toward a systems biology approach will be highlighted. The meeting will include a commemorative lecture in honor of the career and accomplishments of the late Emeritus Professor Bruce A. Stone, a pioneer in wall research who contributed over 40 years of outstanding studies on plant cell wall structure, function, synthesis and remodeling including emphasis on plant cell wall beta-glucans and arabinogalactans. The dwindling supply of fossil fuels will not suffice to meet our future energy and industrial product needs. Plant biomass is the renewable resource that will fill a large part of the void left by vanishing fossil fuels. It is therefore critical that basic research scientists interact closely with industrial researchers to critically evaluate the current state of knowledge regarding how plant biomass, which is largely plant cell walls, is synthesized and utilized by the plant. A final

  13. The lantibiotic mersacidin is a strong inducer of the cell wall stress response of Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Sahl Hans-Georg

    2008-10-01

    Full Text Available Abstract Background The lantibiotic mersacidin is an antimicrobial peptide of 20 amino acids that is ribosomally produced by Bacillus sp. strain HIL Y-85,54728. Mersacidin acts by complexing the sugar phosphate head group of the peptidoglycan precursor lipid II, thereby inhibiting the transglycosylation reaction of peptidoglycan biosynthesis. Results Here, we studied the growth of Staphylococcus aureus in the presence of subinhibitory concentrations of mersacidin. Transcriptional data revealed an extensive induction of the cell wall stress response, which is partly controlled by the two-component regulatory system VraSR. In contrast to other cell wall-active antibiotics such as vancomycin, very low concentrations of mersacidin (0.15 × MIC were sufficient for induction. Interestingly, the cell wall stress response was equally induced in vancomycin intermediately resistant S. aureus (VISA and in a highly susceptible strain. Since the transcription of the VraDE ABC transporter genes was induced up to 1700-fold in our experiments, we analyzed the role of VraDE in the response to mersacidin. However, the deletion of the vraE gene did not result in an increased susceptibility to mersacidin compared to the wild type strain. Moreover, the efficacy of mersacidin was not affected by an increased cell wall thickness, which is part of the VISA-type resistance mechanism and functions by trapping the vancomycin molecules in the cell wall before they reach lipid II. Therefore, the relatively higher concentration of mersacidin at the membrane might explain why mersacidin is such a strong inducer of VraSR compared to vancomycin. Conclusion In conclusion, mersacidin appears to be a strong inducer of the cell wall stress response of S. aureus at very low concentrations, which reflects its general mode of action as a cell wall-active peptide as well as its use of a unique target site on lipid II. Additionally, mersacidin does not seem to be a substrate for the

  14. Atkinesin-13A modulates cell-wall synthesis and cell expansion in Arabidopsis thaliana via the THESEUS1 pathway.

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    Ushio Fujikura

    2014-09-01

    Full Text Available Growth of plant organs relies on cell proliferation and expansion. While an increasingly detailed picture about the control of cell proliferation is emerging, our knowledge about the control of cell expansion remains more limited. We demonstrate here that the internal-motor kinesin AtKINESIN-13A (AtKIN13A limits cell expansion and cell size in Arabidopsis thaliana, with loss-of-function atkin13a mutants forming larger petals with larger cells. The homolog, AtKINESIN-13B, also affects cell expansion and double mutants display growth, gametophytic and early embryonic defects, indicating a redundant role of the two genes. AtKIN13A is known to depolymerize microtubules and influence Golgi motility and distribution. Consistent with this function, AtKIN13A interacts genetically with ANGUSTIFOLIA, encoding a regulator of Golgi dynamics. Reduced AtKIN13A activity alters cell wall structure as assessed by Fourier-transformed infrared-spectroscopy and triggers signalling via the THESEUS1-dependent cell-wall integrity pathway, which in turn promotes the excess cell expansion in the atkin13a mutant. Thus, our results indicate that the intracellular activity of AtKIN13A regulates cell expansion and wall architecture via THESEUS1, providing a compelling case of interplay between cell wall integrity sensing and expansion.

  15. Photoinhibition of stem elongation by blue and red light: effects on hydraulic and cell wall properties

    Science.gov (United States)

    Kigel, J.; Cosgrove, D. J.

    1991-01-01

    The underlying mechanism of photoinhibition of stem elongation by blue (BL) and red light (RL) was studied in etiolated seedlings of pea (Pisum sativum L. cv Alaska). Brief BL irradiations resulted in fast transient inhibition of elongation, while a delayed (lag approximately 60 minutes) but prolonged inhibition was observed after brief RL. Possible changes in the hydraulic and wall properties of the growing cells during photoinhibition were examined. Cell sap osmotic pressure was unaffected by BL and RL, but both irradiations increased turgor pressure by approximately 0.05 megapascal (pressure-probe technique). Cell wall yielding was analyzed by in vivo stress relaxation (pressure-block technique). BL and RL reduced the initial rate of relaxation by 38 and 54%, while the final amount of relaxation was decreased by 48 and 10%, respectively. These results indicate that RL inhibits elongation mainly by lowering the wall yield coefficient, while most of the inhibitory effect of BL was due to an increase of the yield threshold. Mechanical extensibility of cell walls (Instron technique) was decreased by BL and RL, mainly due to a reduction in the plastic component of extensibility. Thus, photoinhibitions of elongation by both BL and RL are achieved through changes in cell wall properties, and are not due to effects on the hydraulic properties of the cell.

  16. Early evolution of polyisoprenol biosynthesis and the origin of cell walls

    Directory of Open Access Journals (Sweden)

    Jonathan Lombard

    2016-10-01

    Full Text Available After being a matter of hot debate for years, the presence of lipid membranes in the last common ancestor of extant organisms (i.e., the cenancestor now begins to be generally accepted. By contrast, cenancestral cell walls have attracted less attention, probably owing to the large diversity of cell walls that exist in the three domains of life. Many prokaryotic cell walls, however, are synthesized using glycosylation pathways with similar polyisoprenol lipid carriers and topology (i.e., orientation across the cell membranes. Here, we provide the first systematic phylogenomic report on the polyisoprenol biosynthesis pathways in the three domains of life. This study shows that, whereas the last steps of the polyisoprenol biosynthesis are unique to the respective domain of life of which they are characteristic, the enzymes required for basic unsaturated polyisoprenol synthesis can be traced back to the respective last common ancestor of each of the three domains of life. As a result, regardless of the topology of the tree of life that may be considered, the most parsimonious hypothesis is that these enzymes were inherited in modern lineages from the cenancestor. This observation supports the presence of an enzymatic mechanism to synthesize unsaturated polyisoprenols in the cenancestor and, since these molecules are notorious lipid carriers in glycosylation pathways involved in the synthesis of a wide diversity of prokaryotic cell walls, it provides the first indirect evidence of the existence of a hypothetical unknown cell wall synthesis mechanism in the cenancestor.

  17. Cell wall alterations in the leaves of fusariosis-resistant and susceptible pineapple cultivars.

    Science.gov (United States)

    de Farias Viégas Aquije, Glória Maria; Zorzal, Poliana Belisário; Buss, David Shaun; Ventura, José Aires; Fernandes, Patricia Machado Bueno; Fernandes, Antonio Alberto Ribeiro

    2010-10-01

    Fusariosis, caused by the fungus Fusarium subglutinans f. sp. ananas (Syn. F. guttiforme), is one of the main phytosanitary threats to pineapple (Ananas comosus var. comosus). Identification of plant cell responses to pathogens is important in understanding the plant-pathogen relationship and establishing strategies to improve and select resistant cultivars. Studies of the structural properties and phenolic content of cell walls in resistant (Vitoria) and susceptible (Perola) pineapple cultivars, related to resistance to the fungus, were performed. The non-chlorophyll base of physiologically mature leaves was inoculated with a conidia suspension. Analyses were performed post-inoculation by light, atomic force, scanning and transmission electron microscopy, and measurement of cell wall-bound phenolic compounds. Non-inoculated leaves were used as controls to define the constitutive tissue characteristics. Analyses indicated that morphological differences, such as cell wall thickness, cicatrization process and lignification, were related to resistance to the pathogen. Atomic force microscopy indicated a considerable difference in the mechanical properties of the resistant and susceptible cultivars, with more structural integrity, associated with higher levels of cell wall-bound phenolics, found in the resistant cultivar. p-Coumaric and ferulic acids were shown to be the major phenolics bound to the cell walls and were found in higher amounts in the resistant cultivar. Leaves of the resistant cultivar had reduced fungal penetration and a faster and more effective cicatrization response compared to the susceptible cultivar.

  18. Function and Biosynthesis of Cell Wall α-1,3-Glucan in Fungi

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    Akira Yoshimi

    2017-11-01

    Full Text Available Although α-1,3-glucan is a major cell wall polysaccharide in filamentous fungi, its biological functions remain unclear, except that it acts as a virulence factor in animal and plant pathogenic fungi: it conceals cell wall β-glucan on the fungal cell surface to circumvent recognition by hosts. However, cell wall α-1,3-glucan is also present in many of non-pathogenic fungi. Recently, the universal function of α-1,3-glucan as an aggregation factor has been demonstrated. Applications of fungi with modified cell wall α-1,3-glucan in the fermentation industry and of in vitro enzymatically-synthesized α-1,3-glucan in bio-plastics have been developed. This review focuses on the recent progress in our understanding of the biological functions and biosynthetic mechanism of cell wall α-1,3-glucan in fungi. We briefly consider the history of studies on α-1,3-glucan, overview its biological functions and biosynthesis, and finally consider the industrial applications of fungi deficient in α-1,3-glucan.

  19. Substrate Preferences Establish the Order of Cell Wall Assembly in Staphylococcus aureus.

    Science.gov (United States)

    Schaefer, Kaitlin; Owens, Tristan W; Kahne, Daniel; Walker, Suzanne

    2018-02-21

    The Gram-positive bacterial cell wall is a large supramolecular structure and its assembly requires coordination of complex biosynthetic pathways. In the step that merges the two major biosynthetic pathways in Staphylococcus aureus cell wall assembly, conserved protein ligases attach wall teichoic acids to peptidoglycan, but the order of biosynthetic events is a longstanding question. Here, we use a chemical approach to define which of the possible peptidoglycan intermediates are substrates for wall-teichoic acid ligases, thereby establishing the order of cell wall assembly. We have developed a strategy to make defined glycan chain-length polymers of either un-cross-linked or cross-linked peptidoglycan, and we find that wall teichoic acid ligases cannot transfer wall teichoic acid precursors to the cross-linked substrates. A 1.9 Å crystal structure of a LytR-CpsA-Psr (LCP) family ligase in complex with a wall teichoic acid precursor defines the location of the peptidoglycan binding site as a long, narrow groove, and suggests that the basis for selectivity is steric exclusion of cross-linked peptidoglycan. Consistent with this hypothesis, we have found that chitin oligomers are good substrates for transfer, showing that LCPs do not discriminate cross-linked from un-cross-linked peptidoglycan substrates by recognizing features of the un-cross-linked stem peptide. We conclude that wall teichoic acids are coupled to un-cross-linked peptidoglycan chains at an early stage of peptidoglycan synthesis and may create marks that define the proper spacing of subsequent cross-links.

  20. Strong adhesion of Saos-2 cells to multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Matsuoka, Makoto; Akasaka, Tsukasa; Totsuka, Yasunori; Watari, Fumio

    2010-01-01

    In recent years, carbon nanotubes (CNTs) have been considered potential biomedical materials because of their unique character. The aim of this study was to investigate the response of a human osteoblast-like cell line - Saos-2 - on single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs). The surface of a culture dish was coated with CNTs, and Saos-2 cells were cultured for three days. Cell morphology, viability, alkaline phosphatase (ALP) activity, adhesion, and vinculin expression were evaluated. The result showed high cell viability and strong adhesion to MWCNTs. Saos-2 cultured on MWCNTs exhibited vinculin expression throughout the cell body, while the cells attached to SWCNTs and glass were mostly limited to their periphery. Our results suggest that CNT coatings promote cell activity and adhesiveness. These findings indicate that MWCNTs could be used as surface coating materials to promote cell adhesion.

  1. Analysis of the influence of radiation quality on the effectiveness of small doses for induction of reproductive death and chromosome aberrations in mammalian cells

    International Nuclear Information System (INIS)

    Barendsen, G.W.

    1978-01-01

    A comparison of RBE - LET relations are made for reproductive death and chromosome aberrations in mammalian cells, as a means of providing insight into the type of mechanisms involved. An analysis of the survival curves for X-rays and gamma rays is discussed and a schematic representation is presented of differences in the dependence of the effectiveness per unit dose on LET, for which data were derived from experiments with X-rays, gamma rays, fast neutrons and heavy ions. (Auth./C.F.)

  2. Asc1 supports cell-wall integrity near bud sites by a Pkc1 independent mechanism.

    Directory of Open Access Journals (Sweden)

    Daniel Melamed

    Full Text Available BACKGROUND: The yeast ribosomal protein Asc1 is a WD-protein family member. Its mammalian ortholog, RACK1 was initially discovered as a receptor for activated protein C kinase (PKC that functions to maintain the active conformation of PKC and to support its movement to target sites. In the budding yeast though, a connection between Asc1p and the PKC signaling pathway has never been reported. METHODOLOGY/PRINCIPAL FINDINGS: In the present study we found that asc1-deletion mutant (asc1Delta presents some of the hallmarks of PKC signaling mutants. These include an increased sensitivity to staurosporine, a specific Pkc1p inhibitor, and susceptibility to cell-wall perturbing treatments such as hypotonic- and heat shock conditions and zymolase treatment. Microscopic analysis of asc1Delta cells revealed cell-wall invaginations near bud sites after exposure to hypotonic conditions, and the dynamic of cells' survival after this stress further supports the involvement of Asc1p in maintaining the cell-wall integrity during the mid-to late stages of bud formation. Genetic interactions between asc1 and pkc1 reveal synergistic sensitivities of a double-knock out mutant (asc1Delta/pkc1Delta to cell-wall stress conditions, and high basal level of PKC signaling in asc1Delta. Furthermore, Asc1p has no effect on the cellular distribution or redistribution of Pkc1p at optimal or at cell-wall stress conditions. CONCLUSIONS/SIGNIFICANCE: Taken together, our data support the idea that unlike its mammalian orthologs, Asc1p acts remotely from Pkc1p, to regulate the integrity of the cell-wall. We speculate that its role is exerted through translation regulation of bud-site related mRNAs during cells' growth.

  3. Chalcone Synthase (CHS) Gene Suppression in Flax Leads to Changes in Wall Synthesis and Sensing Genes, Cell Wall Chemistry and Stem Morphology Parameters

    Science.gov (United States)

    Zuk, Magdalena; Działo, Magdalena; Richter, Dorota; Dymińska, Lucyna; Matuła, Jan; Kotecki, Andrzej; Hanuza, Jerzy; Szopa, Jan

    2016-01-01

    The chalcone synthase (CHS) gene controls the first step in the flavonoid biosynthesis. In flax, CHS down-regulation resulted in tannin accumulation and reduction in lignin synthesis, but plant growth was not affected. This suggests that lignin content and thus cell wall characteristics might be modulated through CHS activity. This study investigated the possibility that CHS affects cell wall sensing as well as polymer content and arrangement. CHS-suppressed and thus lignin-reduced plants showed significant changes in expression of genes involved in both synthesis of components and cell wall sensing. This was accompanied by increased levels of cellulose and hemicellulose. CHS-reduced flax also showed significant changes in morphology and arrangement of the cell wall. The stem tissue layers were enlarged averagely twofold compared to the control, and the number of fiber cells more than doubled. The stem morphology changes were accompanied by reduction of the crystallinity index of the cell wall. CHS silencing induces a signal transduction cascade that leads to modification of plant metabolism in a wide range and thus cell wall structure. PMID:27446124

  4. Enhanced lipid recovery from Nannochloropsis microalgae by treatment with optimized cell wall degrading enzyme mixtures.

    Science.gov (United States)

    Zuorro, Antonio; Miglietta, Selenia; Familiari, Giuseppe; Lavecchia, Roberto

    2016-07-01

    A statistical mixture design approach was used to investigate the effects of cell wall degrading enzymes on the recovery of lipids from Nannochloropsis sp. A preliminary screening of potentially suitable enzyme preparations, including lysozyme, cellulase and different types of hemicellulases, was carried out. The most effective preparations were then taken as basic components for the formulation of enzyme mixtures. Optimized ternary mixtures consisting of cellulase and two hemicellulases were obtained which allowed the recovery of up to 37.2g of lipids per 100g of dry biomass. SEM and TEM images of the enzymatically treated microalga revealed extensive cell damage, with degradation of the cell wall and release of intracellular material. Overall, the results obtained demonstrate that the mixture design method can be used to prepare cell wall degrading enzyme cocktails that can significantly improve the recovery of lipids or other valuable components from microalgae. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Plant cell wall-degrading enzymes and their secretion in plant-pathogenic fungi.

    Science.gov (United States)

    Kubicek, Christian P; Starr, Trevor L; Glass, N Louise

    2014-01-01

    Approximately a tenth of all described fungal species can cause diseases in plants. A common feature of this process is the necessity to pass through the plant cell wall, an important barrier against pathogen attack. To this end, fungi possess a diverse array of secreted enzymes to depolymerize the main structural polysaccharide components of the plant cell wall, i.e., cellulose, hemicellulose, and pectin. Recent advances in genomic and systems-level studies have begun to unravel this diversity and have pinpointed cell wall-degrading enzyme (CWDE) families that are specifically present or enhanced in plant-pathogenic fungi. In this review, we discuss differences between the CWDE arsenal of plant-pathogenic and non-plant-pathogenic fungi, highlight the importance of individual enzyme families for pathogenesis, illustrate the secretory pathway that transports CWDEs out of the fungal cell, and report the transcriptional regulation of expression of CWDE genes in both saprophytic and phytopathogenic fungi.

  6. The innate immune protein Nod2 binds directly to MDP, a bacterial cell wall fragment.

    Science.gov (United States)

    Grimes, Catherine Leimkuhler; Ariyananda, Lushanti De Zoysa; Melnyk, James E; O'Shea, Erin K

    2012-08-22

    Mammalian Nod2 is an intracellular protein that is implicated in the innate immune response to the bacterial cell wall and is associated with the development of Crohn's disease, Blau syndrome, and gastrointestinal cancers. Nod2 is required for an immune response to muramyl dipeptide (MDP), an immunostimulatory fragment of bacterial cell wall, but it is not known whether MDP binds directly to Nod2. We report the expression and purification of human Nod2 from insect cells. Using novel MDP self-assembled monolayers (SAMs), we provide the first biochemical evidence for a direct, high-affinity interaction between Nod2 and MDP.

  7. Regulation of cell wall plasticity by nucleotide metabolism in Lactococcus lactis

    NARCIS (Netherlands)

    Solopova, Ana; Formosa-Dague, Cécile; Courtin, Pascal; Furlan, Sylviane; Veiga, Patrick; Péchoux, Christine; Armalyte, Julija; Sadauskas, Mikas; Kok, Jan; Hols, Pascal; Dufrêne, Yves F; Kuipers, Oscar P; Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius

    2016-01-01

    To ensure optimal cell growth and separation, and to adapt to environmental parameters, bacteria have to maintain a balance between cell wall (CW) rigidity and flexibility. This can be achieved by a concerted action of peptidoglycan (PG) hydrolases and PG synthesizing/modifying enzymes. In a search

  8. The structure of cell wall alpha-glucan from fission yeast

    NARCIS (Netherlands)

    Grün, Christian H.; Hochstenbach, Frans; Humbel, Bruno M.; Verkleij, Arie J.; Sietsma, J. Hans; Klis, Frans M.; Kamerling, Johannis P.; Vliegenthart, Johannes F. G.

    2005-01-01

    Morphology and structural integrity of fungal cells depend on cell wall polysaccharides. The chemical structure and biosynthesis of two types of these polysaccharides, chitin and (1-->3)-beta-glucan, have been studied extensively, whereas little is known about alpha-glucan. Here we describe the

  9. The structure of cell wall alpha-glucan from fission yeast.

    NARCIS (Netherlands)

    Grün, C.H.; Hochstenbach, F.; Humbel, B.M.; Verkleij, A.J.; Sietsma, J.H.; Klis, F.M.; Kamerling, J.P.; Vliegenthart, J.F.G.

    2005-01-01

    Morphology and structural integrity of fungal cells depend on cell wall polysaccharides. The chemical structure and biosynthesis of two types of these polysaccharides, chitin and (1rarr3)-beta-glucan, have been studied extensively, whereas little is known about alpha-glucan. Here we describe the

  10. Revealing organization of cellulose in wood cell walls by Raman imaging

    Science.gov (United States)

    Umesh P. Agarwal; Sally A. Ralph

    2007-01-01

    Anisotropy of cellulose organization in mature black spruce wood cell wall was investigated by Raman imaging using a 1 [mu]m lateral-resolution capable confocal Raman microscope. In these studies, wood cross sections (CS) and radial longitudinal sections (LS) that were partially delignified by acid chlorite treatment were used. In the case of CS where latewood cells...

  11. pH within pores in plant fiber cell walls assessed by Fluorescence Ratio Imaging

    DEFF Research Database (Denmark)

    Hidayat, Budi Juliman; Thygesen, Lisbeth Garbrecht; Johansen, Katja Salomon

    2013-01-01

    The pH within cell wall pores of filter paper fibers and hemp fibers was assessed by Fluorescence Ratio Imaging (FRIM). It was found that the Donnan effect affected the pH measured within the fibers. When the conductivity of the added liquid was low (0. 7 mS), pH values were lower within the cell...

  12. Flow cytogenetics: progress toward chromosomal aberration detection

    International Nuclear Information System (INIS)

    Carrano, A.V.; Gray, J.W.; Van Dilla, M.A.

    1977-01-01

    Using clonal derivatives of the Chinese hamster M3-1 cell line, we demonstrate the potential of flow systems to karyotype homogeneous aberrations (aberrations which are identical and present in every cell) and to detect heterogeneous aberrations (aberrations which occur randomly in a population and are not identical in every cell). Flow cytometry (FCM) of ethidium bromide stained isolated chromosomes from clone 650A of the M3-1 cells distinguishes nine chromosome types from the fourteen present in the actual karyotype. X-irradiation of this parent 650A clone produced two sub-clones with an altered flow karyotype, that is, their FCM distributions were characterized by the addition of new peaks and alterations in area under existing peaks. From the relative DNA content and area for each peak, as determined by computer analysis, we predicted that each clone had undergone a reciprocal translocation involving chromosomes from two peaks. This prediction was confirmed by Giemsa-banding the metaphase cells. Heterogeneous aberrations are reflected in the flow karyotype as an increase in background, that is, an increase in area underlying the chromosome peaks. This increase is dose dependent but, as yet, the sample variability has been too large for quantitative analysis. Flow sorting of the valleys between chromosome peaks produces enriched fractions of aberrant chromosomes for visual analysis. These approaches are potentially applicable to the analysis of chromsomal aberrations induced by environmental contaminants

  13. Evaluation of Tritium Behavior in the Epoxy Painted Concrete Wall of ITER Hot Cell