Sample records for cell wall type-ii

  1. Assay and heterologous expression in Pichia pastoris of plant cell wall type-II membrane anchored glycosyltransferases

    DEFF Research Database (Denmark)

    Petersen, Bent Larsen; Egelund, Jack; Damager, Iben


    Two Arabidopsis xylosyltransferases, designated RGXT1 and RGXT2, were recently expressed in Baculovirus transfected insect cells and by use of the free sugar assay shown to catalyse transfer of D-xylose from UDP-α-D-xylose to L-fucose and derivatives hereof. We have now examined expression of RGX...... nmol conversion of substrate • min-1 • µl medium-1) similar to those of RGXT1 and RGXT2 expressed in Baculovirus transfected insect Sf9 cells. In summary, the data presented suggest that Pichia is an attractive host candidate for expression of plant glycosyltransferases....

  2. Towards Optimal Diagnosis of Type II Germ Cell Tumors

    NARCIS (Netherlands)

    J.A. Stoop (Hans)


    textabstractThe aim of the work described in this thesis is to improve the understanding of the pathobiology of testicular cancer (type II Germ Cell Tumors) to create possibilities for optimalization of diagnosis for this type of malignancy in routine pathology laboratories. The different studies pr

  3. Quark matter coupled to domain walls in Bianchi types II, VIII and IX Universes

    Indian Academy of Sciences (India)

    S D Katore; M M Sancheti; S P Hatkar


    In this study of Bianchi types II, VIII and IX Universes, quark matter coupled to domain walls in the context of general relativity are explored. To obtain deterministic solution of the Einstein’s field equations, various techniques are adopted. The features of the obtained solution are discussed.

  4. Towards Optimal Diagnosis of Type II Germ Cell Tumors


    Stoop, Hans


    textabstractThe aim of the work described in this thesis is to improve the understanding of the pathobiology of testicular cancer (type II Germ Cell Tumors) to create possibilities for optimalization of diagnosis for this type of malignancy in routine pathology laboratories. The different studies presented here show valuable additional information on the microscopic diagnostics in daily practice. This enables proper and complete diagnosis of this relative rare variant of cancer ensuring the b...

  5. Characterization of cloned cells from an immortalized fetal pulmonary type II cell line

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    Henderson, R.F.; Waide, J.J.; Lechner, J.F.


    A cultured cell line that maintained expression of pulmonary type II cell markers of differentiation would be advantageous to generate a large number of homogenous cells in which to study the biochemical functions of type II cells. Type II epithelial cells are the source of pulmonary surfactant and a cell of origin for pulmonary adenomas. Last year our laboratory reported the induction of expression of two phenotypic markers of pulmonary type II cells (alkaline phosphatase activity and surfactant lipid synthesis) in cultured fetal rat lung epithelial (FRLE) cells, a spontaneously immortalized cell line of fetal rat lung type II cell origin. Subsequently, the induction of the ability to synthesize surfactant lipid became difficult to repeat. We hypothesized that the cell line was heterogenuous and some cells were more like type II cells than others. The purpose of this study was to test this hypothesis and to obtain a cultured cell line with type II cell phenotypic markers by cloning several FRLE cells and characterizing them for phenotypic markers of type II cells (alkaline phosphatase activity and presence of surfactant lipids). Thirty cloned cell lines were analyzed for induced alkaline phosphatase activity (on x-axis) and for percent of phospholipids that were disaturated (i.e., surfactant).

  6. Alveolar epithelial type II cell: defender of the alveolus revisited

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    Fehrenbach Heinz


    Full Text Available Abstract In 1977, Mason and Williams developed the concept of the alveolar epithelial type II (AE2 cell as a defender of the alveolus. It is well known that AE2 cells synthesise, secrete, and recycle all components of the surfactant that regulates alveolar surface tension in mammalian lungs. AE2 cells influence extracellular surfactant transformation by regulating, for example, pH and [Ca2+] of the hypophase. AE2 cells play various roles in alveolar fluid balance, coagulation/fibrinolysis, and host defence. AE2 cells proliferate, differentiate into AE1 cells, and remove apoptotic AE2 cells by phagocytosis, thus contributing to epithelial repair. AE2 cells may act as immunoregulatory cells. AE2 cells interact with resident and mobile cells, either directly by membrane contact or indirectly via cytokines/growth factors and their receptors, thus representing an integrative unit within the alveolus. Although most data support the concept, the controversy about the character of hyperplastic AE2 cells, reported to synthesise profibrotic factors, proscribes drawing a definite conclusion today.

  7. Stimulation of DNA synthesis in cultured rat alveolar type II cells

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    Leslie, C.C.; McCormick-Shannon, K.; Robinson, P.C.; Mason, R.J.


    Restoration of the alveolar epithelium after injury is thought to be dependent on the proliferation of alveolar type II cells. To understand the factors that may be involved in promoting type II cell proliferation in vivo, we determined the effect of potential mitogens and culture substrata on DNA synthesis in rat alveolar type II cells in primary culture. Type II cells cultured in basal medium containing 10% fetal bovine serum (FBS) exhibited essentially no DNA synthesis. Factors that stimulated /sup 3/H-thymidine incorporation included cholera toxin, epidermal growth factor, and rat serum. The greatest degree of stimulation was achieved by plating type II cells on an extracellular matrix prepared from bovine corneal endothelial cells and then by culturing the pneumocytes in medium containing rat serum, cholera toxin, insulin, and epidermal growth factor. Under conditions of stimulation of /sup 3/H-thymidine incorporation there was an increased DNA content per culture dish but no increase in cell number. The ability of various culture conditions to promote DNA synthesis in type II cells was verified by autoradiography. Type II cells were identified by the presence of cytoplasmic inclusions, which were visualized by tannic acid staining before autoradiography. These results demonstrate the importance of soluble factors and culture substratum in stimulating DNA synthesis in rat alveolar type II cells in primary culture.

  8. Activation of Type II Cells into Regenerative Stem Cell Antigen-1+ Cells during Alveolar Repair (United States)

    Kumar, Varsha Suresh; Zhang, Wei; Rehman, Jalees; Malik, Asrar B.


    The alveolar epithelium is composed of two cell types: type I cells comprise 95% of the gas exchange surface area, whereas type II cells secrete surfactant, while retaining the ability to convert into type I cells to induce alveolar repair. Using lineage-tracing analyses in the mouse model of Pseudomonas aeruginosa–induced lung injury, we identified a population of stem cell antigen (Sca)-1–expressing type II cells with progenitor cell properties that mediate alveolar repair. These cells were shown to be distinct from previously reported Sca-1–expressing bronchioalveolar stem cells. Microarray and Wnt reporter studies showed that surfactant protein (Sp)-C+Sca-1+ cells expressed Wnt signaling pathway genes, and inhibiting Wnt/β-catenin signaling prevented the regenerative function of Sp-C+Sca-1+ cells in vitro. Thus, P. aeruginosa–mediated lung injury induces the generation of a Sca-1+ subset of type II cells. The progenitor phenotype of the Sp-C+Sca-1+ cells that mediates alveolar epithelial repair might involve Wnt signaling. PMID:25474582

  9. Proteolysis of synaptobrevin, syntaxin, and SNAP-25 in alveolar epithelial type II cells. (United States)

    Zimmerman, U J; Malek, S K; Liu, L; Li, H L


    Synaptobrevin-2, syntaxin-1, and SNAP-25 were identified in rat alveolar epithelial type II cells by Western blot analysis. Synaptobrevin-2 was localized in the lamellar bodies, and syntaxin-1 and SNAP-25 were found in 0.4% Nonidet P40-soluble and -insoluble fractions, respectively, of the type II cells. When the isolated type II cells were stimulated for secretion with calcium ionophore A23187 or with phorbol 12-myristate 13-acetate, these proteins were found to have been proteolyzed. Preincubation of cells with calpain inhibitor II (N-acetylleucylleucylmethionine), however, prevented the proteolysis. Treatment of the cell lysate with exogenous calpain resulted in a time-dependent decrease of these proteins. The data suggest that synaptobrevin, syntaxin, and SNAP-25 are subject to proteolytic modification by activated calpain in intact type II cells stimulated for secretion.

  10. Recognition of lysophosphatidylcholine by type II NKT cells and protection from an inflammatory liver disease (United States)

    Maricic, Igor; Girardi, Enrico; Zajonc, Dirk M.; Kumar, Vipin


    Summary Lipids presented by the major histocompatibility complex (MHC) class I-like molecule, CD1d, are recognized by natural killer T (NKT) cells, which can be broadly categorized into two subsets. The well-characterized type I NKT cells, express a semi-invariant T cell receptor (TCR) and can recognize both α- and β-linked glycolipids, whereas type II NKT cells are less well studied, express a relatively diverse TCR repertoire, and recognize β-linked lipids. Recent structural studies have shown a distinct mode of recognition of a self-glycolipid sulfatide bound to CD1d by a type II NKT TCR. To further characterize antigen recognition by these cells we have used the structural data and screened other small molecules able to bind to CD1d and activate type II NKT cells. Using plate-bound CD1d and APC-based antigen presentation assay we found that phospholipids such as lysophosphatidylcholine (LPC) can stimulate the sulfatide-reactive type II NKT hybridoma Hy19.3 in a CD1d-dependent manner. Using plasmon resonance studies we found that this type II NKT TCR binds with CD1d-bound LPC with micromolar affinities similar to that for sulfatide. Furthermore LPC-mediated activation of type II NKT cells leads to anergy induction in type I NKT cells and affords protection from ConA-induced hepatitis. These data indicate that, in addition to self-glycolipids, self-lysophospholipids are also recognized by type II NKT cells. Since lysophospholipids are involved during inflammation our findings have implications for not only understanding activation of type II NKT cells in physiological settings but also for the development of immune intervention in inflammatory diseases. PMID:25261475

  11. Molecular Design of D-Tr-A Type II Organic Sensitizers for Dye Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    李士锋; 杨希川; 瞿定峰; 王维瀚; 王瑜; 孙立成


    Four new type II organic dyes with D-n-A structure (donor-n-conjugated-acceptor) and two typical type II sen- sitizers based on catechol as reference dyes are synthesized and applied in dye sensitized solar cells (DSCs). The four dyes can be adsorbed on TiO2 through hydroxyl group directly. Electron injection can occur not only through the anchoring group (hydroxyl group) but also through the electron-withdrawing group (-CN) located close to the semiconductor surface. Experimental results show that the type II sensitizers with a D-π-A system obviously out- perform the typical type II sensitizers providing much higher conversion efficiency due to the strong electronic push-pull effect. Among these dyes, LS223 gives the best solar energy conversion efficiency of 3.6%, with Jsc = 7.3 mAocm 2, Voc=0.69 V, FF=0.71, the maximum IPCE value reaches 74.9%.

  12. Arachidonate metabolism increases as rat alveolar type II cells differentiate in vitro

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    Lipchik, R.J.; Chauncey, J.B.; Paine, R.; Simon, R.H.; Peters-Golden, M. (Univ. of Michigan, Ann Arbor (USA))


    Rat type II alveolar epithelial cells are known to undergo morphological and functional changes when maintained in culture for several days. Having previously demonstrated that these cells can deacylate free arachidonic acid (AA) and metabolize it to products of the cyclooxygenase pathway, the present study was undertaken to determine whether in vitro differentiation was accompanied by alterations in the availability and metabolism of AA. We assessed the constitutive and ionophore A23187-induced deacylation and metabolism of endogenous AA, as well as the metabolism of exogenously supplied AA, in primary cultures of rat type II cells at days 2, 4, and 7 after isolation. Levels of free endogenous AA were increased at day 4, whereas eicosanoid synthesis, predominantly prostaglandin E2 and prostacyclin, increased markedly only at day 7. A similar time course of augmentation of prostanoid release was seen in response to exogenous AA. Type II cells cultured on fibronectin, intended to hasten cell flattening and spreading, demonstrated accelerated increases in available free AA in response to A23187; cells cultured on basement membrane derived from Engelbreth-Holm-Swarm mouse sarcoma, known to maintain the type II phenotype, exhibited diminished levels of available free AA. From these findings, we conclude that alterations in arachidonate metabolism are linked to alterations in cellular phenotype. The potentiation of eicosanoid synthesis accompanying in vitro differentiation suggests a possible role for the alveolar epithelium in the modulation of inflammation and fibrosis in the distal lung.

  13. The MicroRNA 29 Family Promotes Type II Cell Differentiation in Developing Lung. (United States)

    Guo, Wei; Benlhabib, Houda; Mendelson, Carole R


    Lung alveolar type II cells uniquely synthesize surfactant, a developmentally regulated lipoprotein that is essential for breathing. Expression of the gene (SFTPA) encoding the major surfactant protein, SP-A, in midgestation human fetal lung (HFL) is dramatically induced by cyclic AMP (cAMP). cAMP induction of SP-A expression is repressed by transforming growth factor β (TGF-β) and by hypoxia. In this study, we found that expression of the microRNA 29 (miR-29) family was significantly upregulated in epithelial cells isolated from mouse fetal lung during late gestation and in epithelial cells isolated from HFL explants during type II cell differentiation in culture. miR-29 expression in cultured HFL epithelial cells was increased by cAMP and inhibited by hypoxia, whereas the miR-29 target, TGF-β2, was coordinately decreased. Knockdown of the miR-29 family in cultured HFL type II cells blocked cAMP-induced SP-A expression and accumulation of surfactant-containing lamellar bodies, suggesting their physiological relevance. This occurred through derepression of TGF-β signaling. Notably, cAMP increased binding of endogenous thyroid transcription factor 1 (TTF-1/Nkx2.1) to the miR-29ab1 promoter in HFL type II cells, and TTF-1 increased miR-29ab1 promoter-driven luciferase activity in cotransfection assays. Together, these findings identify miR-29 family members as TTF-1-driven mediators of SP-A expression and type II cell differentiation through repression of TGF-β signaling.

  14. N=1 domain wall solutions of massive type II supergravity as generalized geometries

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    Louis, J. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Hamburg Univ. (Germany). Zentrum fuer Mathematische Physik; Vaula, S. [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik]|[Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)


    We study N=1 domain wall solutions of type IIB supergravity compactified on a Calabi-Yau manifold in the presence of RR and NS electric and magnetic fluxes. We show that the dynamics of the scalar fields along the direction transverse to the domain wall is described by gradient flow equations controlled by a superpotential W. We then provide a geometrical interpretation of the gradient flow equations in terms of the mirror symmetric compactification of type IIA. They correspond to a set of generalized Hitchin flow equations of a manifold with SU(3) x SU(3)structure which is fibered over the direction transverse to the domain wall. (Orig.)

  15. Collagen Type II Enhances Chondrogenesis in Adipose Tissue-Derived Stem Cells by Affecting Cell Shape

    NARCIS (Netherlands)

    Lu, ZuFu; Doulabi, Behrouz Zandieh; Huang, ChunLing; Bank, Ruud A.; Helder, Marco N.


    Ideally, biomaterials have inductive properties, favoring specific lineage differentiation. For chondrogenic induction, these properties have been attributed to collagen type II. However, the underlying mechanisms are largely unknown. This study aimed to investigate whether collagen type II favors c

  16. Collagen type II enhances chondrogenesis in adipose tissue-derived stem cells by affecting cell shape

    NARCIS (Netherlands)

    Lu, Z.; Doulabi, B.Z.; Huang, C.; Bank, R.A.; Helder, M.N.


    Ideally, biomaterials have inductive properties, favoring specific lineage differentiation. For chondrogenic induction, these properties have been attributed to collagen type II. However, the underlying mechanisms are largely unknown. This study aimed to investigate whether collagen type II favors c

  17. Dichloroacetate Decreases Cell Health and Activates Oxidative Stress Defense Pathways in Rat Alveolar Type II Pneumocytes

    Directory of Open Access Journals (Sweden)

    Alexis Valauri-Orton


    Full Text Available Dichloroacetate (DCA is a water purification byproduct that is known to be hepatotoxic and hepatocarcinogenic and to induce peripheral neuropathy and damage macrophages. This study characterizes the effects of the haloacetate on lung cells by exposing rat alveolar type II (L2 cells to 0–24 mM DCA for 6–24 hours. Increasing DCA concentration and the combination of increasing DCA concentration plus longer exposures decrease measures of cellular health. Length of exposure has no effect on oxidative stress biomarkers, glutathione, SOD, or CAT. Increasing DCA concentration alone does not affect total glutathione or its redox ratio but does increase activity in the SOD/CAT oxidative stress defense pathway. These data suggest that alveolar type II cells rely on SOD and CAT more than glutathione to combat DCA-induced stress.

  18. The adaptor protein SAP regulates type II NKT-cell development, cytokine production, and cytotoxicity against lymphoma. (United States)

    Weng, Xiufang; Liao, Chia-Min; Bagchi, Sreya; Cardell, Susanna L; Stein, Paul L; Wang, Chyung-Ru


    CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT-cell TCR transgenic mouse model, we demonstrated that CD1d-expressing hematopoietic cells, but not thymic epithelial cells, meditate efficient selection of type II NKT cells. Furthermore, we showed that SAP regulates type II NKT-cell development by controlling early growth response 2 protein and promyelocytic leukemia zinc finger expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IFN regulatory factor 4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP.

  19. Jamming dynamics of stretch-induced surfactant release by alveolar type II cells. (United States)

    Majumdar, Arnab; Arold, Stephen P; Bartolák-Suki, Erzsébet; Parameswaran, Harikrishnan; Suki, Béla


    Secretion of pulmonary surfactant by alveolar epithelial type II cells is vital for the reduction of interfacial surface tension, thus preventing lung collapse. To study secretion dynamics, rat alveolar epithelial type II cells were cultured on elastic membranes and cyclically stretched. The amounts of phosphatidylcholine, the primary lipid component of surfactant, inside and outside the cells, were measured using radiolabeled choline. During and immediately after stretch, cells secreted less surfactant than unstretched cells; however, stretched cells secreted significantly more surfactant than unstretched cells after an extended lag period. We developed a model based on the hypothesis that stretching leads to jamming of surfactant traffic escaping the cell, similar to vehicular traffic jams. In the model, stretch increases surfactant transport from the interior to the exterior of the cell. This transport is mediated by a surface layer with a finite capacity due to the limited number of fusion pores through which secretion occurs. When the amount of surfactant in the surface layer approaches this capacity, interference among lamellar bodies carrying surfactant reduces the rate of secretion, effectively creating a jam. When the stretch stops, the jam takes an extended time to clear, and subsequently the amount of secreted surfactant increases. We solved the model analytically and show that its dynamics are consistent with experimental observations, implying that surfactant secretion is a fundamentally nonlinear process with memory representing collective behavior at the level of single cells. Our results thus highlight the importance of a jamming dynamics in stretch-induced cellular secretory processes.

  20. Establishment and evaluation of a stable cattle type II alveolar epithelial cell line.

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    Feng Su

    Full Text Available Macrophages and dendritic cells are recognized as key players in the defense against mycobacterial infection. Recent research has confirmed that alveolar epithelial cells (AECs also play important roles against mycobacterium infections. Thus, establishing a stable cattle AEC line for future endogenous immune research on bacterial invasion is necessary. In the present study, we first purified and immortalized type II AECs (AEC II cells by transfecting them with a plasmid containing the human telomerase reverse trancriptase gene. We then tested whether or not the immortalized cells retained the basic physiological properties of primary AECs by reverse-transcription polymerase chain reaction and Western blot. Finally, we tested the secretion capacity of immortalized AEC II cells upon stimulation by bacterial invasion. The cattle type II alveolar epithelial cell line (HTERT-AEC II that we established retained lung epithelial cell characteristics: the cells were positive for surfactants A and B, and they secreted tumor necrosis factor-α and interleukin-6 in response to bacterial invasion. Thus, the cell line we established is a potential tool for research on the relationship between AECs and Mycobacterium tuberculosis.

  1. Neocartilage formation from mesenchymal stem cells grown in type II collagen-hyaluronan composite scaffolds. (United States)

    Yeh, Hsi-Yi; Lin, Ting-Yu; Lin, Chen-Huan; Yen, B Linju; Tsai, Ching-Lin; Hsu, Shan-Hui


    Three-dimensional (3D) collagen type II-hyaluronan (HA) composite scaffolds (CII-HA) which mimics the extracellular environment of natural cartilage were fabricated in this study. Rheological measurements demonstrated that the incorporation of HA increased the compression modulus of the scaffolds. An initial in vitro evaluation showed that scaffolds seeded with porcine chondrocytes formed cartilaginous-like tissue after 8 weeks, and HA functioned to promote the growth of chondrocytes into scaffolds. Placenta-derived multipotent cells (PDMC) and gingival fibroblasts (GF) were seeded on tissue culture polystyrene (TCPS), CII-HA films, and small intestinal submucosa (SIS) sheets for comparing their chondrogenesis differentiation potentials with those of adipose-derived adult stem cells (ADAS) and bone marrow-derived mesenchymal stem cells (BMSC). Among different cells, PDMC showed the greatest chondrogenic differentiation potential on both CII-HA films and SIS sheets upon TGF-β3 induction, followed by GF. This was evidenced by the up-regulation of chondrogenic genes (Sox9, aggrecan, and collagen type II), which was not observed for cells grown on TCPS. This finding suggested the essential role of substrate materials in the chondrogenic differentiation of PDMC and GF. Neocartilage formation was more obvious in both PDMC and GF cells plated on CII-HA composite scaffolds vs. 8-layer SIS at 28 days in vitro. Finally, implantation of PDMC/CII-HA constructs into NOD-SCID mice confirmed the formation of tissue-engineered cartilage in vivo.

  2. Accurate segmentation of leukocyte in blood cell images using Atanassov's intuitionistic fuzzy and interval Type II fuzzy set theory. (United States)

    Chaira, Tamalika


    In this paper automatic leukocyte segmentation in pathological blood cell images is proposed using intuitionistic fuzzy and interval Type II fuzzy set theory. This is done to count different types of leukocytes for disease detection. Also, the segmentation should be accurate so that the shape of the leukocytes is preserved. So, intuitionistic fuzzy set and interval Type II fuzzy set that consider either more number of uncertainties or a different type of uncertainty as compared to fuzzy set theory are used in this work. As the images are considered fuzzy due to imprecise gray levels, advanced fuzzy set theories may be expected to give better result. A modified Cauchy distribution is used to find the membership function. In intuitionistic fuzzy method, non-membership values are obtained using Yager's intuitionistic fuzzy generator. Optimal threshold is obtained by minimizing intuitionistic fuzzy divergence. In interval type II fuzzy set, a new membership function is generated that takes into account the two levels in Type II fuzzy set using probabilistic T co norm. Optimal threshold is selected by minimizing a proposed Type II fuzzy divergence. Though fuzzy techniques were applied earlier but these methods failed to threshold multiple leukocytes in images. Experimental results show that both interval Type II fuzzy and intuitionistic fuzzy methods perform better than the existing non-fuzzy/fuzzy methods but interval Type II fuzzy thresholding method performs little bit better than intuitionistic fuzzy method. Segmented leukocytes in the proposed interval Type II fuzzy method are observed to be distinct and clear.

  3. Vacuolar ATPase regulates surfactant secretion in rat alveolar type II cells by modulating lamellar body calcium.

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    Narendranath Reddy Chintagari

    Full Text Available Lung surfactant reduces surface tension and maintains the stability of alveoli. How surfactant is released from alveolar epithelial type II cells is not fully understood. Vacuolar ATPase (V-ATPase is the enzyme responsible for pumping H(+ into lamellar bodies and is required for the processing of surfactant proteins and the packaging of surfactant lipids. However, its role in lung surfactant secretion is unknown. Proteomic analysis revealed that vacuolar ATPase (V-ATPase dominated the alveolar type II cell lipid raft proteome. Western blotting confirmed the association of V-ATPase a1 and B1/2 subunits with lipid rafts and their enrichment in lamellar bodies. The dissipation of lamellar body pH gradient by Bafilomycin A1 (Baf A1, an inhibitor of V-ATPase, increased surfactant secretion. Baf A1-stimulated secretion was blocked by the intracellular Ca(2+ chelator, BAPTA-AM, the protein kinase C (PKC inhibitor, staurosporine, and the Ca(2+/calmodulin-dependent protein kinase II (CaMKII, KN-62. Baf A1 induced Ca(2+ release from isolated lamellar bodies. Thapsigargin reduced the Baf A1-induced secretion, indicating cross-talk between lamellar body and endoplasmic reticulum Ca(2+ pools. Stimulation of type II cells with surfactant secretagogues dissipated the pH gradient across lamellar bodies and disassembled the V-ATPase complex, indicating the physiological relevance of the V-ATPase-mediated surfactant secretion. Finally, silencing of V-ATPase a1 and B2 subunits decreased stimulated surfactant secretion, indicating that these subunits were crucial for surfactant secretion. We conclude that V-ATPase regulates surfactant secretion via an increased Ca(2+ mobilization from lamellar bodies and endoplasmic reticulum, and the activation of PKC and CaMKII. Our finding revealed a previously unrealized role of V-ATPase in surfactant secretion.

  4. Potassium currents in type II vestibular hair cells isolated from the guinea-pig's crista ampullaris. (United States)

    Griguer, C; Kros, C J; Sans, A; Lehouelleur, J


    Type II vestibular hair cells were isolated from cristae ampullares of guinea-pig and maintained in vitro for 2-3 h. Outward membrane currents were studied under whole-cell voltage-clamp conditions. Type II hair cells had resting potentials of about -45 mV. Depolarizing voltage steps from a holding potential of -80 or -90 mV induced time- and voltage-dependent outward currents which slowly decayed to a sustained level. Tail currents reversed at about -70 mV, indicating that the outward currents were mainly carried by potassium ions. The currents had an activation threshold around -50 mV. The transient component was completely removed by a depolarizing pre-pulse positive to -10 mV. While bath application of 4-aminopyridine (5 mM) reduced both components, extracellular tetraethylammonium (10 mM) or zero calcium preferentially diminished the sustained current. We conclude that at least two potassium conductances are present, a delayed rectifier with a relatively fast inactivation and a calcium-dependent potassium current. Depolarizing current injections induced an electrical resonance in the voltage responses, with a frequency of 25-100 Hz, larger currents causing higher frequencies.

  5. MCP-1 expression by rat type II alveolar epithelial cells in primary culture. (United States)

    Paine, R; Rolfe, M W; Standiford, T J; Burdick, M D; Rollins, B J; Strieter, R M


    Recruitment and activation of mononuclear phagocytes are potentially critical regulatory events for control of pulmonary inflammation. Located at the boundary between the alveolar airspace and the interstitium, alveolar epithelial cells are ideally situated to regulate the recruitment and activation of mononuclear phagocytes through the production of cytokines in response to inflammatory stimulation from the alveolar space. To test this hypothesis, we investigated the production of monocyte chemotactic polypeptide-1 (MCP-1), a protein that is chemotactic for and that activates monocytes, by rat type II alveolar epithelial cells in primary culture. Immunocytochemical staining using anti-murine JE, an antibody recognizing rat MCP-1, demonstrated cell-associated MCP-1 Ag throughout the monolayer. The intensity of staining was increased in response to IL-1 beta. When type II epithelial cells formed a tight monolayer on a filter support, there was polar secretion of MCP-1 Ag into the apical compartment by both control and IL-1-stimulated cells as measured by specific MCP-1 ELISA. Northern blot analysis revealed that IL-1 and TNF-alpha stimulated MCP-1 mRNA expression in a dose-dependent manner, whereas dexamethasone blocked MCP-1 expression by cells stimulated with IL-1. In contrast to previous results using transformed epithelial cell lines, MCP-1 mRNA was induced in these primary cultures directly by stimulation with LPS. These data suggest that alveolar epithelial cells may have an important and previously unrecognized role in the initiation and maintenance of inflammatory processes in the lung by recruiting and activating circulating monocytes through the production of MCP-1.

  6. STAT3 regulates ABCA3 expression and influences lamellar body formation in alveolar type II cells. (United States)

    Matsuzaki, Yohei; Besnard, Valérie; Clark, Jean C; Xu, Yan; Wert, Susan E; Ikegami, Machiko; Whitsett, Jeffrey A


    ATP-Binding Cassette A3 (ABCA3) is a lamellar body associated lipid transport protein required for normal synthesis and storage of pulmonary surfactant in type II cells in the alveoli. In this study, we demonstrate that STAT3, activated by IL-6, regulates ABCA3 expression in vivo and in vitro. ABCA3 mRNA and immunostaining were decreased in adult mouse lungs in which STAT3 was deleted from the respiratory epithelium (Stat3(Delta/Delta) mice). Consistent with the role of STAT3, intratracheal IL-6 induced ABCA3 expression in vivo. Decreased ABCA3 and abnormalities in the formation of lamellar bodies, the intracellular site of surfactant lipid storage, were observed in Stat3(Delta/Delta) mice. Expression of SREBP1a and 1c, SCAP, ABCA3, and AKT mRNAs was inhibited by deletion of Stat3 in type II cells isolated from Stat3(Delta/Delta) mice. The activities of PI3K and AKT were required for normal Abca3 gene expression in vitro. AKT activation induced SREBP expression and increased the activity of the Abca3 promoter in vitro, consistent with the role of STAT3 signaling, at least in part via SREBP, in the regulation of ABCA3. ABCA3 expression is regulated by IL-6 in a pathway that includes STAT3, PI3K, AKT, SCAP, and SREBP. Activation of STAT3 after exposure to IL-6 enhances ABCA3 expression, which, in turn, influences pulmonary surfactant homeostasis.

  7. Transcriptional profile of Mycobacterium tuberculosis replicating in type II alveolar epithelial cells.

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    Michelle B Ryndak

    Full Text Available Mycobacterium tuberculosis (M. tb infection is initiated by the few bacilli inhaled into the alveolus. Studies in lungs of aerosol-infected mice provided evidence for extensive replication of M. tb in non-migrating, non-antigen-presenting cells in the alveoli during the first 2-3 weeks post-infection. Alveoli are lined by type II and type I alveolar epithelial cells (AEC which outnumber alveolar macrophages by several hundred-fold. M. tb DNA and viable M. tb have been demonstrated in AEC and other non-macrophage cells of the kidney, liver, and spleen in autopsied tissues from latently-infected subjects from TB-endemic regions indicating systemic bacterial dissemination during primary infection. M. tb have also been demonstrated to replicate rapidly in A549 cells (type II AEC line and acquire increased invasiveness for endothelial cells. Together, these results suggest that AEC could provide an important niche for bacterial expansion and development of a phenotype that promotes dissemination during primary infection. In the current studies, we have compared the transcriptional profile of M. tb replicating intracellularly in A549 cells to that of M. tb replicating in laboratory broth, by microarray analysis. Genes significantly upregulated during intracellular residence were consistent with an active, replicative, metabolic, and aerobic state, as were genes for tryptophan synthesis and for increased virulence (ESAT-6, and ESAT-6-like genes, esxH, esxJ, esxK, esxP, and esxW. In contrast, significant downregulation of the DevR (DosR regulon and several hypoxia-induced genes was observed. Stress response genes were either not differentially expressed or were downregulated with the exception of the heat shock response and those induced by low pH. The intra-type II AEC M. tb transcriptome strongly suggests that AEC could provide a safe haven in which M. tb can expand dramatically and disseminate from the lung prior to the elicitation of adaptive immune

  8. Monomeric, porous type II collagen scaffolds promote chondrogenic differentiation of human bone marrow mesenchymal stem cells in vitro (United States)

    Tamaddon, M.; Burrows, M.; Ferreira, S. A.; Dazzi, F.; Apperley, J. F.; Bradshaw, A.; Brand, D. D.; Czernuszka, J.; Gentleman, E.


    Osteoarthritis (OA) is a common cause of pain and disability and is often associated with the degeneration of articular cartilage. Lesions to the articular surface, which are thought to progress to OA, have the potential to be repaired using tissue engineering strategies; however, it remains challenging to instruct cell differentiation within a scaffold to produce tissue with appropriate structural, chemical and mechanical properties. We aimed to address this by driving progenitor cells to adopt a chondrogenic phenotype through the tailoring of scaffold composition and physical properties. Monomeric type-I and type-II collagen scaffolds, which avoid potential immunogenicity associated with fibrillar collagens, were fabricated with and without chondroitin sulfate (CS) and their ability to stimulate the chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells was assessed. Immunohistochemical analyses showed that cells produced abundant collagen type-II on type-II scaffolds and collagen type-I on type-I scaffolds. Gene expression analyses indicated that the addition of CS – which was released from scaffolds quickly – significantly upregulated expression of type II collagen, compared to type-I and pure type-II scaffolds. We conclude that collagen type-II and CS can be used to promote a more chondrogenic phenotype in the absence of growth factors, potentially providing an eventual therapy to prevent OA.

  9. Monomeric, porous type II collagen scaffolds promote chondrogenic differentiation of human bone marrow mesenchymal stem cells in vitro. (United States)

    Tamaddon, M; Burrows, M; Ferreira, S A; Dazzi, F; Apperley, J F; Bradshaw, A; Brand, D D; Czernuszka, J; Gentleman, E


    Osteoarthritis (OA) is a common cause of pain and disability and is often associated with the degeneration of articular cartilage. Lesions to the articular surface, which are thought to progress to OA, have the potential to be repaired using tissue engineering strategies; however, it remains challenging to instruct cell differentiation within a scaffold to produce tissue with appropriate structural, chemical and mechanical properties. We aimed to address this by driving progenitor cells to adopt a chondrogenic phenotype through the tailoring of scaffold composition and physical properties. Monomeric type-I and type-II collagen scaffolds, which avoid potential immunogenicity associated with fibrillar collagens, were fabricated with and without chondroitin sulfate (CS) and their ability to stimulate the chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells was assessed. Immunohistochemical analyses showed that cells produced abundant collagen type-II on type-II scaffolds and collagen type-I on type-I scaffolds. Gene expression analyses indicated that the addition of CS - which was released from scaffolds quickly - significantly upregulated expression of type II collagen, compared to type-I and pure type-II scaffolds. We conclude that collagen type-II and CS can be used to promote a more chondrogenic phenotype in the absence of growth factors, potentially providing an eventual therapy to prevent OA.

  10. Innate immune response of human alveolar type II cells infected with severe acute respiratory syndrome-coronavirus. (United States)

    Qian, Zhaohui; Travanty, Emily A; Oko, Lauren; Edeen, Karen; Berglund, Andrew; Wang, Jieru; Ito, Yoko; Holmes, Kathryn V; Mason, Robert J


    Severe acute respiratory syndrome (SARS)-coronavirus (CoV) produces a devastating primary viral pneumonia with diffuse alveolar damage and a marked increase in circulating cytokines. One of the major cell types to be infected is the alveolar type II cell. However, the innate immune response of primary human alveolar epithelial cells infected with SARS-CoV has not been defined. Our objectives included developing a culture system permissive for SARS-CoV infection in primary human type II cells and defining their innate immune response. Culturing primary human alveolar type II cells at an air-liquid interface (A/L) improved their differentiation and greatly increased their susceptibility to infection, allowing us to define their primary interferon and chemokine responses. Viral antigens were detected in the cytoplasm of infected type II cells, electron micrographs demonstrated secretory vesicles filled with virions, virus RNA concentrations increased with time, and infectious virions were released by exocytosis from the apical surface of polarized type II cells. A marked increase was evident in the mRNA concentrations of interferon-β and interferon-λ (IL-29) and in a large number of proinflammatory cytokines and chemokines. A surprising finding involved the variability of expression of angiotensin-converting enzyme-2, the SARS-CoV receptor, in type II cells from different donors. In conclusion, the cultivation of alveolar type II cells at an air-liquid interface provides primary cultures in which to study the pulmonary innate immune responses to infection with SARS-CoV, and to explore possible therapeutic approaches to modulating these innate immune responses.

  11. Alveolar Type II Cells Escape Stress Failure Caused by Tonic Stretch through Transient Focal Adhesion Disassembly

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    Xiao-Yang Liu, Xiao-Fei Chen, Yan-Hong Ren, Qing-Yuan Zhan, Chen Wang, Chun Yang


    Full Text Available Mechanical ventilation-induced excessive stretch of alveoli is reported to induce cellular stress failure and subsequent lung injury, and is therefore an injurious factor to the lung. Avoiding cellular stress failure is crucial to ventilator-induced lung injury (VILI treatment. In the present study, primary rat alveolar type II (ATII cells were isolated to evaluate their viability and the mechanism of their survival under tonic stretch. By the annexin V/ PI staining and flow cytometry assay, we demonstrated that tonic stretch-induced cell death is an immediate injury of mechanical stress. In addition, immunofluorescence and immunoblots assay showed that the cells experienced an expansion-contraction-reexpansion process, accompanied by partial focal adhesion (FA disassembly during contraction. Manipulation of integrin adherent affinity by altering bivalent cation levels in the culture medium and applying an integrin neutralizing antibody showed that facilitated adhesion affinity promoted cell death under tonic stretch, while lower level of adhesion protected the cells from stretch-induced stress failure. Finally, a simplified numerical model was established to reveal that adequate disassembly of FAs reduced the forces transmitting throughout the cell. Taken together, these results indicate that ATII cells escape stress failure caused by tonic stretch via active cell morphological remodeling, during which cells transiently disassemble FAs to unload mechanical forces.

  12. Glutathione Reductase Targeted to Type II Cells Does Not Protect Mice from Hyperoxic Lung Injury (United States)

    Heyob, Kathryn M.; Rogers, Lynette K.; Welty, Stephen E.


    Exposure of the lung epithelium to reactive oxygen species without adequate antioxidant defenses leads to airway inflammation, and may contribute to lung injury. Glutathione peroxidase catalyzes the reduction of peroxides by oxidation of glutathione (GSH) to glutathione disulfide (GSSG), which can in turn be reduced by glutathione reductase (GR). Increased levels of GSSG have been shown to correlate negatively with outcome after oxidant exposure, and increased GR activity has been protective against hyperoxia in lung epithelial cells in vitro. We tested the hypothesis that increased GR expression targeted to type II alveolar epithelial cells would improve outcome in hyperoxia-induced lung injury. Human GR with a mitochondrial targeting sequence was targeted to mouse type II cells using the SPC promoter. Two transgenic lines were identified, with Line 2 having higher lung GR activities than Line 1. Both transgenic lines had lower lung GSSG levels and higher GSH/GSSG ratios than wild-type. Six-week-old wild-type and transgenic mice were exposed to greater than 95% O2 or room air (RA) for 84 hours. After exposure, Line 2 mice had higher right lung/body weight ratios and lavage protein concentrations than wild-type mice, and both lines 1 and 2 had lower GSSG levels than wild-type mice. These findings suggest that GSSG accumulation in the lung may not play a significant role in the development of hyperoxic lung injury, or that compensatory responses to unregulated GR expression render animals more susceptible to hyperoxic lung injury. PMID:18566333

  13. Autophagy protects type II alveolar epithelial cells from Mycobacterium tuberculosis infection

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    Guo, Xu-Guang [Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi' an (China); Department of Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Ji, Tian-Xing [Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou (China); Xia, Yong, E-mail: [Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi' an (China); Ma, Yue-Yun, E-mail: [Center for Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi' an (China)


    Highlights: ► We investigated the protective effect of autophagy pathway against MTB infection. ► MTB-infected A549 cells had higher LDH release. ► Inhibition of autophagy signaling significantly enhanced the MTB-induced necrosis. ► Autophagy prevents apoptosis and promotes cell survival in infected cells. -- Abstract: This study was designed to investigate the protective effect of the autophagy signaling pathway against Mycobacterium tuberculosis infection in type II alveolar epithelial cells. An in vitro M. tuberculosis system was established using human A549 cells. Infection-induced changes in the expression of the autophagic marker LC3 were assessed by reverse transcription-PCR and Western blotting. Morphological changes in autophagosomes were detected by transmission electron microscopy (TEM). The function of the autophagy signaling pathway during infection was assessed by measuring the level of cell death and the amount of lactate dehydrogenase (LDH) released in the presence or absence of the inhibitor 3-methyladenine (3-MA). In addition, effects on LDH release were assessed after the siRNA-mediated knockdown of the essential autophagosomal structural membrane protein Atg5. LC3 mRNA expression was significantly reduced in M.tuberculosis-infected A549 cells (16888.76 ± 1576.34 vs. uninfected: 12744.29 ± 1089.37; P < 0.05). TEM revealed M.tuberculosis bacilli-containing compartments that were surrounded by double membranes characteristic of the autophagic process. M.tuberculosis-infected A549 cells released more LDH (1.45 ± 0.12 vs. uninfected: 0.45 ± 0.04; P < 0.05). The inhibition of autophagy signaling significantly enhanced M.tuberculosis-induced necrosis (3-MA: 75 ± 5% vs. untreated: 15 ± 1%; P < 0.05) and LDH release (3-MA: 2.50 ± 0.24 vs. untreated: 0.45 ± 0.04; Atg5 knockdown: 3.19 ± 0.29 vs. untreated: 1.28 ± 0.11; P < 0.05). Our results indicate that autophagy signaling pathway prevents apoptosis in type II alveolar epithelial cells

  14. Mechanism and efficiency of cell death of type II photosensitizers: effect of zinc chelation. (United States)

    Pavani, Christiane; Iamamoto, Yassuko; Baptista, Maurício S


    A series of meso-substituted tetra-cationic porphyrins, which have methyl and octyl substituents, was studied in order to understand the effect of zinc chelation and photosensitizer subcellular localization in the mechanism of cell death. Zinc chelation does not change the photophysical properties of the photosensitizers (all molecules studied are type II photosensitizers) but affects considerably the interaction of the porphyrins with membranes, reducing mitochondrial accumulation. The total amount of intracellular reactive species induced by treating cells with photosensitizer and light is similar for zinc-chelated and free-base porphyrins that have the same alkyl substituent. Zinc-chelated porphyrins, which are poorly accumulated in mitochondria, show higher efficiency of cell death with features of apoptosis (higher MTT response compared with trypan blue staining, specific acridine orange/ethidium bromide staining, loss of mitochondrial transmembrane potential, stronger cytochrome c release and larger sub-G1 cell population), whereas nonchelated porphyrins, which are considerably more concentrated in mitochondria, triggered mainly necrotic cell death. We hypothesized that zinc-chelation protects the photoinduced properties of the porphyrins in the mitochondrial environment.

  15. Alveolar type II epithelial cell dysfunction in rat experimental hepatopulmonary syndrome (HPS.

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    Wenli Yang

    Full Text Available The hepatopulmonary syndrome (HPS develops when pulmonary vasodilatation leads to abnormal gas exchange. However, in human HPS, restrictive ventilatory defects are also observed supporting that the alveolar epithelial compartment may also be affected. Alveolar type II epithelial cells (AT2 play a critical role in maintaining the alveolar compartment by producing four surfactant proteins (SPs, SP-A, SP-B, SP-C and SP-D which also facilitate alveolar repair following injury. However, no studies have evaluated the alveolar epithelial compartment in experimental HPS. In this study, we evaluated the alveolar epithelial compartment and particularly AT2 cells in experimental HPS induced by common bile duct ligation (CBDL. We found a significant reduction in pulmonary SP production associated with increased apoptosis in AT2 cells after CBDL relative to controls. Lung morphology showed decreased mean alveolar chord length and lung volumes in CBDL animals that were not seen in control models supporting a selective reduction of alveolar airspace. Furthermore, we found that administration of TNF-α, the bile acid, chenodeoxycholic acid, and FXR nuclear receptor activation (GW4064 induced apoptosis and impaired SP-B and SP-C production in alveolar epithelial cells in vitro. These results imply that AT2 cell dysfunction occurs in experimental HPS and is associated with alterations in the alveolar epithelial compartment. Our findings support a novel contributing mechanism in experimental HPS that may be relevant to humans and a potential therapeutic target.

  16. Effects of Perfluorocarbons on surfactant exocytosis and membrane properties in isolated alveolar type II cells

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    Ravasio Andrea


    Full Text Available Abstract Background Perfluorocarbons (PFC are used to improve gas exchange in diseased lungs. PFC have been shown to affect various cell types. Thus, effects on alveolar type II (ATII cells and surfactant metabolism can be expected, data, however, are controversial. Objective The study was performed to test two hypotheses: (I the effects of PFC on surfactant exocytosis depend on their respective vapor pressures; (II different pathways of surfactant exocytosis are affected differently by PFC. Methods Isolated ATII cells were exposed to two PFC with different vapor pressures and spontaneous surfactant exocytosis was measured. Furthermore, surfactant exocytosis was stimulated by either ATP, PMA or Ionomycin. The effects of PFC on cell morphology, cellular viability, endocytosis, membrane permeability and fluidity were determined. Results The spontaneous exocytosis was reduced by PFC, however, the ATP and PMA stimulated exocytosis was slightly increased by PFC with high vapor pressure. In contrast, Ionomycin-induced exocytosis was decreased by PFC with low vapor pressure. Cellular uptake of FM 1-43 - a marker of membrane integrity - was increased. However, membrane fluidity, endocytosis and viability were not affected by PFC incubation. Conclusions We conclude that PFC effects can be explained by modest, unspecific interactions with the plasma membrane rather than by specific interactions with intracellular targets.

  17. Stem cell-like gene expression in ovarian cancer predicts type II subtype and prognosis.

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    Matthew Schwede

    Full Text Available Although ovarian cancer is often initially chemotherapy-sensitive, the vast majority of tumors eventually relapse and patients die of increasingly aggressive disease. Cancer stem cells are believed to have properties that allow them to survive therapy and may drive recurrent tumor growth. Cancer stem cells or cancer-initiating cells are a rare cell population and difficult to isolate experimentally. Genes that are expressed by stem cells may characterize a subset of less differentiated tumors and aid in prognostic classification of ovarian cancer. The purpose of this study was the genomic identification and characterization of a subtype of ovarian cancer that has stem cell-like gene expression. Using human and mouse gene signatures of embryonic, adult, or cancer stem cells, we performed an unsupervised bipartition class discovery on expression profiles from 145 serous ovarian tumors to identify a stem-like and more differentiated subgroup. Subtypes were reproducible and were further characterized in four independent, heterogeneous ovarian cancer datasets. We identified a stem-like subtype characterized by a 51-gene signature, which is significantly enriched in tumors with properties of Type II ovarian cancer; high grade, serous tumors, and poor survival. Conversely, the differentiated tumors share properties with Type I, including lower grade and mixed histological subtypes. The stem cell-like signature was prognostic within high-stage serous ovarian cancer, classifying a small subset of high-stage tumors with better prognosis, in the differentiated subtype. In multivariate models that adjusted for common clinical factors (including grade, stage, age, the subtype classification was still a significant predictor of relapse. The prognostic stem-like gene signature yields new insights into prognostic differences in ovarian cancer, provides a genomic context for defining Type I/II subtypes, and potential gene targets which following further

  18. Innate immune response to influenza A virus in differentiated human alveolar type II cells. (United States)

    Wang, Jieru; Nikrad, Mrinalini P; Phang, Tzulip; Gao, Bifeng; Alford, Taylor; Ito, Yoko; Edeen, Karen; Travanty, Emily A; Kosmider, Beata; Hartshorn, Kevan; Mason, Robert J


    Alveolar Type II (ATII) cells are important targets for seasonal and pandemic influenza. To investigate the influenza-induced innate immune response in those cells, we measured the global gene expression profile of highly differentiated ATII cells infected with the influenza A virus at a multiplicity of infection of 0.5 at 4 hours and 24 hours after inoculation. Infection with influenza stimulated a significant increase in the mRNA concentrations of many host defense-related genes, including pattern/pathogen recognition receptors, IFN, and IFN-induced genes, chemokines, and suppressors of cytokine signaling. We verified these changes by quantitative real-time RT-PCR. At the protein level, we detected a robust virus-induced secretion of the three glutamic acid-leucine-arginine (ELR)-negative chemokines CXCL9, CXCL10, and CXCL11, according to ELISA. The ultraviolet inactivation of virus abolished the chemokine and cytokine response. Viral infection did not appear to alter the differentiation of ATII cells, as measured by cellular mRNA and concentrations of surfactant proteins. However, viral infection significantly reduced the secretion of surfactant protein (SP)-A and SP-D. In addition, influenza A virus triggered a time-dependent activation of phosphatidylinositol 3-kinase signaling in ATII cells. The inhibition of this pathway significantly decreased the release of infectious virus and the chemokine response, but did not alter virus-induced cell death. This study provides insights into influenza-induced innate immunity in differentiated human ATII cells, and demonstrates that the alveolar epithelium is a critical part of the initial innate immune response to influenza.

  19. MT1-MMP and type II collagen specify skeletal stem cells and their bone and cartilage progeny

    DEFF Research Database (Denmark)

    Szabova, Ludmila; Yamada, Susan S; Wimer, Helen;


    Skeletal formation is dependent on timely recruitment of skeletal stem cells and their ensuing synthesis and remodeling of the major fibrillar collagens, type I collagen and type II collagen, in bone and cartilage tissues during development and postnatal growth. Loss of the major collagenolytic...... activity associated with the membrane-type 1 matrix metalloproteinase (MT1-MMP) results in disrupted skeletal development and growth in both cartilage and bone, where MT1-MMP is required for pericellular collagen dissolution. We show here that reconstitution of MT1-MMP activity in the type II collagen......-expressing cells of the skeleton rescues not only diminished chondrocyte proliferation, but surprisingly, also results in amelioration of the severe skeletal dysplasia associated with MT1-MMP deficiency through enhanced bone formation. Consistent with this increased bone formation, type II collagen was identified...

  20. Ultrastructural Study of Alveolar Epithelial Type II Cells by High-Frequency Oscillatory Ventilation

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    Xiaofei Qin


    Full Text Available Alveolar epithelial type II cells (AECIIs containing lamellar bodies (LBs are alveolar epithelial stem cells that have important functions in the repair of lung structure and function after lung injury. The ultrastructural changes in AECIIs after high-frequency oscillatory ventilation (HFOV with a high lung volume strategy or conventional ventilation were evaluated in a newborn piglet model with acute lung injury (ALI. After ALI with saline lavage, newborn piglets were randomly assigned into five study groups (three piglets in each group, namely, control (no mechanical ventilation, conventional ventilation for 24 h, conventional ventilation for 48 h, HFOV for 24 h, and HFOV for 48 h. The lower tissues of the right lung were obtained to observe the AECII ultrastructure. AECIIs with reduced numbers of microvilli, decreased LBs electron density, and vacuole-like LBs deformity were commonly observed in all five groups. Compared with conventional ventilation groups, the decrease in numbers of microvilli and LBs electron density, as well as LBs with vacuole-like appearance and polymorphic deformity, was less severe in HFOV with high lung volume strategy groups. AECIIs were injured during mechanical ventilation. HFOV with a high lung volume strategy resulted in less AECII damage than conventional ventilation.

  1. Interactions of Francisella tularensis with Alveolar Type II Epithelial Cells and the Murine Respiratory Epithelium.

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    Matthew Faron

    Full Text Available Francisella tularensis is classified as a Tier 1 select agent by the CDC due to its low infectious dose and the possibility that the organism can be used as a bioweapon. The low dose of infection suggests that Francisella is unusually efficient at evading host defenses. Although ~50 cfu are necessary to cause human respiratory infection, the early interactions of virulent Francisella with the lung environment are not well understood. To provide additional insights into these interactions during early Francisella infection of mice, we performed TEM analysis on mouse lungs infected with F. tularensis strains Schu S4, LVS and the O-antigen mutant Schu S4 waaY::TrgTn. For all three strains, the majority of the bacteria that we could detect were observed within alveolar type II epithelial cells at 16 hours post infection. Although there were no detectable differences in the amount of bacteria within an infected cell between the three strains, there was a significant increase in the amount of cellular debris observed in the air spaces of the lungs in the Schu S4 waaY::TrgTn mutant compared to either the Schu S4 or LVS strain. We also studied the interactions of Francisella strains with human AT-II cells in vitro by characterizing the ability of these three strains to invade and replicate within these cells. Gentamicin assay and confocal microscopy both confirmed that F. tularensis Schu S4 replicated robustly within these cells while F. tularensis LVS displayed significantly lower levels of growth over 24 hours, although the strain was able to enter these cells at about the same level as Schu S4 (1 organism per cell, as determined by confocal imaging. The Schu S4 waaY::TrgTn mutant that we have previously described as attenuated for growth in macrophages and mouse virulence displayed interesting properties as well. This mutant induced significant airway inflammation (cell debris and had an attenuated growth phenotype in the human AT-II cells. These

  2. MT1-MMP and type II collagen specify skeletal stem cells and their bone and cartilage progeny

    DEFF Research Database (Denmark)

    Szabova, L.; Yamada, S.S.; Wimer, H.;


    Skeletal formation is dependent on timely recruitment of skeletal stem cells and their ensuing synthesis and remodeling of the major fibrillar collagens, type I collagen and type II collagen, in bone and cartilage tissues during development and postnatal growth. Loss of the major collagenolytic...... activity associated with the membrane-type 1 matrix metalloproteinase (MT1-MMP) results in disrupted skeletal development and growth in both cartilage and bone, where MT1-MMP is required for pericellular collagen dissolution. We show here that reconstitution of MT1-MMP activity in the type II collagen...

  3. Proteomic peptide scan of porphyromonas gingivalis fima type ii for searching potential b-cell epitopes (United States)



    SUMMARY Purpose To identify potential antigenic targets for Porphyromonas gingivalis vaccine development. Materials and methods In the present study, we analyzed the Porphyromonas gingivalis, fimA type II primary amino acid sequence and characterized the similarity to the human proteome at the pentapeptide level. Results We found that exact peptide-peptide profiling of the fimbrial antigen versus the human proteome shows that only 19 out of 344 fimA type II pentapeptides are uniquely owned by the bacterial protein. Conclusions The concept that protein immunogenicity is allocated in rare peptide sequences and the search the Porphyromonas gingivalis fimA type II sequence for peptides unique to the bacterial protein and absent in the human host, might be used in new therapeutical approaches as a significant adjunct to current periodontal therapies. PMID:28042435

  4. 3-D Reconstruction of Macular Type II Cell Innervation Patterns in Space-Flight and Control Rats (United States)

    Ross, Muriel Dorothy; Montgomery, K.; Linton, S.; Cheng, R.; Tomko, David L. (Technical Monitor)


    A semiautomated method for reconstructing objects from serial thin sections has been developed in the Biocomputation Center. The method is being used to completely, for the first time, type II hair cells and their innervations. The purposes are to learn more about the fundamental circuitry of the macula on Earth and to determine whether changes in connectivities occur under space flight conditions. Data captured directly from a transmission electron microscope via a video camera are sent to a graphics workstation. There, the digitized micrographs are mosaicked into sections and contours are traced, registered and displayed by semiautomated methods. Current reconstructions are of type II cells from the medial part of rat maculas collected in-flight on the Space Life Sciences-2 mission, 4.5 hrs post-flight, and from a ground control. Results show that typical type II cells receive processes from tip to six nearby calyces or afferents. Nearly all processes are elongated and have bouton-like enlargements; some have numerous vesicles. Multiple (2 to 4) processes from a single calyx to a type II cell are common, and approximately 1/3 of the processes innervale 2 or 3 type II cells or a neighboring cluster. From 2% to 6% of the cells resemble type I cells morphologically but have demi-calyces. Thus far, increments in synaptic number in type II cells of flight rats are prominent along processes that supply two hair cells. It is clear that reconstruction methods provide insights into details of macular circuitry not obtainable by other techniques. The results demonstrate a morphological basis for interactions between adjacent receptive fields through feed back-feed forward connections, and for dynamic alterations in receptive field range and activity during preprocessing of linear acceleratory information by the maculas. The reconstruction method we have developed will find further applications in the study of the details of neuronal architecture of more complex systems, to

  5. Inactivation of the transforming growth factor beta type II receptor in human small cell lung cancer cell lines

    DEFF Research Database (Denmark)

    Hougaard, S; Nørgaard, P; Abrahamsen, N;


    Transforming growth factor beta (TGF-beta) exerts a growth inhibitory effect on many cell types through binding to two types of receptors, the type I and II receptors. Resistance to TGF-beta due to lack of type II receptor (RII) has been described in some cancer types including small cell lung...... cancer (SCLC). The purpose of this study was to examine the cause of absent RII expression in SCLC cell lines. Northern blot analysis showed that RII RNA expression was very weak in 16 of 21 cell lines. To investigate if the absence of RII transcript was due to mutations, we screened the poly-A tract...... for mutations, but no mutations were detected. Additional screening for mutations of the RII gene revealed a GG to TT base substitution in one cell line, which did not express RII. This mutation generates a stop codon resulting in predicted synthesis of a truncated RII of 219 amino acids. The nature...

  6. The Lamportian cell wall

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    Keiliszewski, M.; Lamport, D. (Michigan State Univ. Plant Research Lab., East Lansing (United States))


    The Lamportian Warp-Weft hypothesis suggests a cellulose-extensin interpenetrating network where extensin mechanically couples the load-bearing cellulose microfibrils in a wall matrix that is best described as a microcomposite. This model is based on data gathered from the extensin-rich walls of tomato and sycamore cell suspension culture, wherein extensin precursors are insolubilized into the wall by undefined crosslinks. The authors recent work with cell walls isolated from intact tissue as well as walls from suspension cultured cells of the graminaceous monocots maize and rice, the non-graminaceous monocot asparagus, the primitive herbaceous dicot sugar beet, and the gymnosperm Douglas Fir indicate that although extensins are ubiquitous to all plant species examined, they are not the major structural protein component of most walls examined. Amino acid analyses of intact and HF-treated walls shows a major component neither an HRGP, nor directly comparable to the glycine-rich wall proteins such as those associated with seed coat walls or the 67 mole% glycine-rich proteins cloned from petunia and soybean. Clearly, structural wall protein alternatives to extensin exist and any cell wall model must take that into account. If we assume that extracellular matrices are a priori network structures, then new Hypless' structural proteins in the maize cell wall raise questions about the sort of network these proteins create: the kinds of crosslinks involved; how they are formed; and the roles played by the small amounts of HRGPs.

  7. Truncated recombinant human SP-D attenuates emphysema and type II cell changes in SP-D deficient mice

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    Mühlfeld Christian


    Full Text Available Abstract Background Surfactant protein D (SP-D deficient mice develop emphysema-like pathology associated with focal accumulations of foamy alveolar macrophages, an excess of surfactant phospholipids in the alveolar space and both hypertrophy and hyperplasia of alveolar type II cells. These findings are associated with a chronic inflammatory state. Treatment of SP-D deficient mice with a truncated recombinant fragment of human SP-D (rfhSP-D has been shown to decrease the lipidosis and alveolar macrophage accumulation as well as production of proinflammatory chemokines. The aim of this study was to investigate if rfhSP-D treatment reduces the structural abnormalities in parenchymal architecture and type II cells characteristic of SP-D deficiency. Methods SP-D knock-out mice, aged 3 weeks, 6 weeks and 9 weeks were treated with rfhSP-D for 9, 6 and 3 weeks, respectively. All mice were sacrificed at age 12 weeks and compared to both PBS treated SP-D deficient and wild-type groups. Lung structure was quantified by design-based stereology at the light and electron microscopic level. Emphasis was put on quantification of emphysema, type II cell changes and intracellular surfactant. Data were analysed with two sided non-parametric Mann-Whitney U-test. Main Results After 3 weeks of treatment, alveolar number was higher and mean alveolar size was smaller compared to saline-treated SP-D knock-out controls. There was no significant difference concerning these indices of pulmonary emphysema within rfhSP-D treated groups. Type II cell number and size were smaller as a consequence of treatment. The total volume of lamellar bodies per type II cell and per lung was smaller after 6 weeks of treatment. Conclusion Treatment of SP-D deficient mice with rfhSP-D leads to a reduction in the degree of emphysema and a correction of type II cell hyperplasia and hypertrophy. This supports the concept that rfhSP-D might become a therapeutic option in diseases that are

  8. Cell Wall Proteome


    Boudart, Georges; Minic, Zoran; Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth; Pont-Lezica, Rafael F


    In this chapter, we will focus on the contribution of proteomics to the identification and determination of the structure and function of CWPs as well as discussing new perspectives in this area. The great variety of proteins found in the plant cell wall is described. Some families, such as glycoside hydrolases, proteases, lectins, and inhibitors of cell wall modifying enzymes, are discussed in detail. Examples of the use of proteomic techniques to elucidate the structure of various cell wall...

  9. Effect of Substituents in Catechol Dye Sensitizers on Photovoltaic Performance of Type II Dye-Sensitized Solar Cells. (United States)

    Ooyama, Yousuke; Kanda, Masahiro; Uenaka, Koji; Ohshita, Joji


    In order to provide a direction in molecular design of catechol (Cat) dyes for type II dye-sensitized solar cells (DSSCs), the dye-to-TiO2 charge-transfer (DTCT) characteristics of Cat dyes with various substituents and their photovoltaic performance in DSSCs are investigated. The Cat dyes with electron-donating or moderately electron-withdrawing substituents exhibit a broad absorption band corresponding to DTCT upon binding to TiO2 films, whereas those with strongly electron-withdrawing substituents exhibit weak DTCT. This study indicates that the introduction of a moderately electron-withdrawing substituent on the Cat moiety leads to not only an increase in the DTCT efficiency, but also the retardation of back electron transfer. This results in favorable conditions for the type II electron-injection pathway from the ground state of the Cat dye to the conduction band of the TiO2 electrode by the photoexcitation of DTCT bands.

  10. Epidermal growth factor regulation in adult rat alveolar type II cells of amiloride-sensitive cation channels. (United States)

    Kemp, P J; Borok, Z; Kim, K J; Lubman, R L; Danto, S I; Crandall, E D


    Using the patch-clamp technique, we studied the effects of epidermal growth factor (EGF) on whole cell and single channel currents in adult rat alveolar epithelial type II cells in primary culture in the presence or absence of EGF for 48 h. In symmetrical sodium isethionate solutions, EGF exposure caused a significant increase in the type II cell whole cell conductance. Amiloride (10 microM) produced approximately 20-30% inhibition of the whole cell conductance in both the presence and absence of EGF, such that EGF caused the magnitude of the amiloride-sensitive component to more than double. Northern analysis showed that alpha-, beta- and gamma-subunits of rat epithelial Na(+) channel (rENaC) steady-state mRNA levels were all significantly decreased by EGF. At the single channel level, all active inside-out patches demonstrated only 25-pS channels that were amiloride sensitive and relatively nonselective for cations (P(Na(+))/P(K(+)) approximately 1.0:0.48). Although the biophysical characteristics (conductance, open-state probability, and selectivity) of the channels from EGF-treated and untreated cells were essentially identical, channel density was increased by EGF; the modal channel per patch was increased from 1 to 2. These findings indicate that EGF increases expression of nonselective, amiloride-sensitive cation channels in adult alveolar epithelial type II cells. The contribution of rENaC to the total EGF-dependent cation current under these conditions is quantitatively less important than that of the nonselective cation channels in these cells.

  11. Secretagogues of lung surfactant increase annexin A7 localization with ABCA3 in alveolar type II cells. (United States)

    Gerelsaikhan, Tudevdagva; Chen, Xiao-Liang; Chander, Avinash


    Membrane fusion between the lamellar bodies and plasma membrane is an obligatory event in the secretion of lung surfactant. Previous studies have postulated a role for annexin A7 (A7) in membrane fusion during exocytosis in some cells including alveolar type II cells. However, the intracellular trafficking of A7 during such fusion is not described. In this study, we investigated association of endogenous A7 with lamellar bodies in alveolar type II cells following treatment with several secretagogues of lung surfactant. Biochemical studies with specific antibodies showed increased membrane-association of cell A7 in type II cells stimulated with agents that increase secretion through different signaling mechanisms. Immuno-fluorescence studies showed increased co-localization of A7 with ABCA3, the lamellar body marker protein. Because these agents increase surfactant secretion through activation of PKC and PKA, we also investigated the effects of PKC and PKA inhibitors, bisindolylmaleimideI (BisI) and H89, respectively, on A7 partitioning. Western blot analysis showed that these inhibitors prevented secretagogue-mediated A7 increase in the membrane fractions. These inhibitors also blocked increased co-localization of A7 with ABCA3 in secretagogue-treated cells, as revealed by immuno-fluorescence studies. In vitro studies with recombinant A7 showed phosphorylation with PKC and PKA. The cell A7 was also phosphorylated in cells treated with surfactant secretagogues. Thus, our studies demonstrate that annexin A7 relocates to lamellar bodies in a phosphorylation-dependent manner. We suggest that activation of protein kinase promotes phosphorylation and membrane-association of A7 presumably to facilitate membrane fusion during lung surfactant secretion.

  12. Interleukin-1 stimulates the expression of type I and type II interleukin-1 receptors in the rat insulinoma cell line Rinm5F; sequencing a rat type II interleukin-1 receptor cDNA. (United States)

    Bristulf, J; Gatti, S; Malinowsky, D; Bjork, L; Sundgren, A K; Bartfai, T


    The insulin secreting rat Rinm5F cells are often used to study the cytotoxic actions of interleukin-1 (IL-1) on pancreatic beta-cells. We demonstrate here that Rinm5F insulinoma cells express both type I and type II interleukin-1 receptor (IL-1R) mRNAs and gene products. IL-1R agonists, recombinant murine IL-1 alpha (rmIL-1 alpha, 10 ng/ml) and recombinant rat IL-1 beta (rrIL-1 beta, 100 pg/ml or 10 ng/ml) induce the upregulation of mRNA expression for both types of IL-1 receptors (IL-1Rs). This effect of rrIL-1 beta is antagonised by preincubation with recombinant human interleukin 1 receptor antagonist protein (rhIL-1ra, 5 micrograms/ml). Furthermore, this rrIL-1 beta induced upregulation of IL-1R mRNAs is blocked by actinomycin D (7.5 micrograms/ml), whereas cycloheximide (20 micrograms/ml) has no effect. The phorbol ester PMA (20 nM) upregulates the expression of mRNAs both IL-1 receptors, whereas glucose (50 mM) upregulates the expression of the type I IL-1R mRNA only. Pretreatment of cells with pertussis toxin (100 ng/ml) partially blocks the rrIL-1 beta induced expression of mRNA for the type I and, to a lesser extent, the type II IL-1R. Incubation of the cells with rrIL-1 beta also induces a time-dependent expression of c-fos, interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) mRNAs. Binding studies with 125I-recombinant human IL-1 beta (125I-rhIL-1 beta) indicate that IL-1R gene products, with the ligand binding characteristics of the type I IL-1R, are constitutively present on Rinm5F cells. Treatment with rrIL-1 beta (6h) increases the number of 125I-rhIL-1 beta binding sites on Rinm5F cells. We have also demonstrated that the number of type II IL-1R binding sites increases after induction with rrIL-1 beta (6h), by indirect immunofluorescence using a monoclonal antibody (ALVA 42) raised against the human type II IL-1R. Furthermore, we have sequenced the type II IL-1R cDNA in the rat insulinoma Rinm5F cells. The comparison of the amino acid

  13. Nonuniform Effect of Carrier Separation Efficiency and Light Absorption in Type-II Perovskite Nanowire Solar Cells. (United States)

    Wang, Weiping; He, Jialun; Cao, Yiyan; Kong, Lijing; Zheng, Xuanli; Wu, Yaping; Chen, Xiaohong; Li, Shuping; Wu, Zhiming; Kang, Junyong


    Coaxial structures exhibit great potential for the application of high-efficiency solar cells due to the novel mechanism of radial charge separation. Here, we intensively investigate the nonuniform effect of carrier separation efficiency (CSE) and light absorption in perovskite-based type-II coaxial nanowire solar cells (ZnO/CH3NH3PbI3). Results show that the CSE rapidly decreases along the radial direction in the shell, and the value at the outer side becomes extremely low for the thick shell. Besides, the position of the main light absorption gradually moves to the outer side with the increase of the shell thickness. As a result, the external quantum efficiency shows a positional dependence with a maximal value close to the border of the nanowire. Eventually, in our case, it is found that the maximal power conversion efficiency of the solar cells reduces from 19.5 to 17.9% under the effect of the nonuniformity of CSE and light absorption. This work provides a basis for the design of high-efficiency solar cells, especially type-II nanowire solar cells.

  14. Exogenous surfactant application in a rat lung ischemia reperfusion injury model: effects on edema formation and alveolar type II cells

    Directory of Open Access Journals (Sweden)

    Richter Joachim


    Full Text Available Abstract Background Prophylactic exogenous surfactant therapy is a promising way to attenuate the ischemia and reperfusion (I/R injury associated with lung transplantation and thereby to decrease the clinical occurrence of acute lung injury and acute respiratory distress syndrome. However, there is little information on the mode by which exogenous surfactant attenuates I/R injury of the lung. We hypothesized that exogenous surfactant may act by limiting pulmonary edema formation and by enhancing alveolar type II cell and lamellar body preservation. Therefore, we investigated the effect of exogenous surfactant therapy on the formation of pulmonary edema in different lung compartments and on the ultrastructure of the surfactant producing alveolar epithelial type II cells. Methods Rats were randomly assigned to a control, Celsior (CE or Celsior + surfactant (CE+S group (n = 5 each. In both Celsior groups, the lungs were flush-perfused with Celsior and subsequently exposed to 4 h of extracorporeal ischemia at 4°C and 50 min of reperfusion at 37°C. The CE+S group received an intratracheal bolus of a modified natural bovine surfactant at a dosage of 50 mg/kg body weight before flush perfusion. After reperfusion (Celsior groups or immediately after sacrifice (Control, the lungs were fixed by vascular perfusion and processed for light and electron microscopy. Stereology was used to quantify edematous changes as well as alterations of the alveolar epithelial type II cells. Results Surfactant treatment decreased the intraalveolar edema formation (mean (coefficient of variation: CE: 160 mm3 (0.61 vs. CE+S: 4 mm3 (0.75; p 3 (0.90 vs. CE+S: 0 mm3; p 3 (0.39 vs. CE+S: 268 mm3 (0.43; p 3(0.10 and CE+S (481 μm3(0.10 compared with controls (323 μm3(0.07; p Conclusion Intratracheal surfactant application before I/R significantly reduces the intraalveolar edema formation and development of atelectases but leads to an increased development of

  15. Type II cytokeratin gene expression is indicative of early cell differentiation in the chick embryo

    Energy Technology Data Exchange (ETDEWEB)

    Charlebois, T.S.


    Embryonic development in vertebrates appears to involve a series of inductive tissue interactions that lead to regional specializations, which eventually become elaborated in the basic body plan of the embryo. The inductive interactions leading to early regionalization of the embryo are often particularly difficult to evaluate because of the absence of available morphological or biochemical evidence that such events have occurred. In the 36 hour chick embryo, the regional subdivision of the early ectoderm is evidence by a marked lens-forming bias in the head ectoderm, which is absent in the presumptive dorsal epidermis of the trunk region. As a strategy for isolating genes whose differential expression might reflect this regional subdivision, a cDNA library from 36 hour embryos was prepared and screened for differential hybridization to ({sup 32}P)cDNA probes synthesized using template RNA isolated from 36 hour head ectoderm and trunk ectoderm. A cDNA clone (T4) was isolated which hybridizes to transcripts present at much higher levels in trunk ectoderm than in head ectoderm. Partial nucleotide and deduced amino acid sequences of this clone indicate that it represents a gene encoding a type II cytokeratin. The distribution of transcripts complementary to the T4 probe was evaluated in early embryos using RNA gel blot analysis and in situ hybridization to tissue sections.

  16. Multiple tissue-specific isoforms of sulfatide activate CD1d-restricted type II NKT cells

    DEFF Research Database (Denmark)

    Blomqvist, Maria; Rhost, Sara; Teneberg, Susann;


    The glycosphingolipid sulfatide (SO(3)-3Galbeta1Cer) is a demonstrated ligand for a subset of CD1d-restricted NKT cells, which could regulate experimental autoimmune encephalomyelitis, a murine model for multiple sclerosis, as well as tumor immunity and experimental hepatitis. Native sulfatide...... is a mixture of sulfatide isoforms, i.e. sulfatide molecules with different long-chain bases and fatty acid chain lengths and saturation. Here, we demonstrate that sulfatide-specific CD1d-restricted murine NKT hybridomas recognized several different sulfatide isoforms. These included the physiologically...... isoforms by a CD1d-restricted NKT-cell clone, and suggest that sulfatide, a major component of the myelin sheet and pancreatic beta-cells, is one of several natural ligands for type II CD1d-restricted NKT cells....

  17. Type II GaSb/GaAs quantum dot/ring stacks with extended photoresponse for efficient solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Carrington, Peter James, E-mail: [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Mahajumi, Abu Syed [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom); Wagener, Magnus C.; Botha, Johannes Reinhardt [Department of Physics, Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Zhuang Qian; Krier, Anthony [Physics Department, Lancaster University, Lancaster LA1 4YB (United Kingdom)


    We report on the fabrication of GaAs based p-i-n solar cells containing 5 and 10 layers of type II GaSb quantum rings grown by molecular beam epitaxy. Solar cells containing quantum rings show improved efficiency at longer wavelengths into the near-IR extending up to 1500 nm and show enhanced short-circuit current under 1 sun illumination compared to a GaAs control cell. A reduction in the open-circuit voltage is observed due to the build-up of internal strain. The MBE growth, formation and photoluminescence of single and stacked layers of GaSb/GaAs quantum rings are also presented.

  18. Gene expression and biological processes influenced by deletion of Stat3 in pulmonary type II epithelial cells

    Directory of Open Access Journals (Sweden)

    Whitsett Jeffrey A


    Full Text Available Abstract Background The signal transducer and activator of transcription 3 (STAT3 mediates gene expression in response to numerous growth factors and cytokines, playing an important role in many cellular processes. To better understand the molecular mechanisms by which Stat3 influences gene expression in the lung, the effect of pulmonary epithelial cell specific deletion of Stat3 on genome wide mRNA expression profiling was assessed. Differentially expressed genes were identified from Affymetrix Murine GeneChips analysis and subjected to gene ontology classification, promoter analysis, pathway mapping and literature mining. Results Total of 791 mRNAs were significantly increased and 314 mRNAs were decreased in response to the deletion of Stat3Δ/Δ in the lung. STAT is the most enriched cis-elements in the promoter regions of those differentially expressed genes. Deletion of Stat3 induced genes influencing protein metabolism, transport, chemotaxis and apoptosis and decreased the expression of genes mediating lipid synthesis and metabolism. Expression of Srebf1 and 2, genes encoding key regulators of fatty acid and steroid biosynthesis, was decreased in type II cells from the Stat3Δ/Δ mice, consistent with the observation that lung surfactant phospholipids content was decreased. Stat3 influenced both pro- and anti-apoptotic pathways that determine cell death or survival. Akt, a potential transcriptional target of Stat3, was identified as an important participant in Stat3 mediated pathways including Jak-Stat signaling, apoptosis, Mapk signaling, cholesterol and fatty acid biosynthesis. Conclusion Deletion of Stat3 from type II epithelial cells altered the expression of genes regulating diverse cellular processes, including cell growth, apoptosis and lipid metabolism. Pathway analysis indicates that STAT3 regulates cellular homeostasis through a complex regulatory network that likely enhances alveolar epithelial cell survival and surfactant

  19. Glycosylation of type II collagen is of major importance for T cell tolerance and pathology in collagen-induced arthritis

    DEFF Research Database (Denmark)

    Bäcklund, Johan; Treschow, Alexandra; Bockermann, Robert;


    Type II collagen (CII) is a candidate cartilage-specific autoantigen, which can become post-translationally modified by hydroxylation and glycosylation. T cell recognition of CII is essential for the development of murine collagen-induced arthritis (CIA) and also occurs in rheumatoid arthritis (RA......). The common denominator of murine CIA and human RA is the presentation of an immunodominant CII-derived glycosylated peptide on murine Aq and human DR4 molecules, respectively. To investigate the importance of T cell recognition of glycosylated CII in CIA development after immunization with heterologous CII......, we treated neonatal mice with different heterologous CII-peptides (non-modified, hydroxylated and galactosylated). Treatment with the galactosylated peptide (galactose at position 264) was superior in protecting mice from CIA. Protection was accompanied by a reduced antibody response to CII...

  20. [Cation ions modulate the ACh-sensitive current in type II vestibular hair cells of guinea pigs]. (United States)

    Guo, Chang-Kai; Zhang, Song; Kong, Wei-Jia; Li, Qing-Tian; Li, Zhi-Wang


    Molecular biological studies and electrophysiological data have demonstrated that acetylcholine (ACh) is the principal cochlear and vestibular efferent neurotransmitter among mammalians. However, the functional roles of ACh in type II vestibular hair cells among mammalians are still unclear, with the exception of the well-known alpha9-containing nicotinic ACh receptor (alpha9-nAChR) in cochlear hair cells and frog saccular hair cells. In this study, the properties of the ACh-sensitive current were investigated by whole-cell patch clamp technique in isolated type II vestibular hair cells of guinea pigs. The direct effect of extracellular ACh was to induce a hyperpolarization effect in type II vestibular hair cells. Type II vestibular hair cells displayed a sustained outward current in response to the perfusion of ACh. It took about 60 s for the ACh-sensitive current to get a complete re-activation. The reversal potential of the ACh-sensitive current was (-66 +/- 8) mV, which indicated that potassium ion was the main carrier of this current. The blocking effect by the submillimolar concentration of tetraethylammonium (TEA) further indicated that extracellular ACh stimulated the calcium-dependent potassium current. Following replacement of the compartment of NaCl in the normal external solution with TrisCl, LiCl or saccharose respectively, the amplitude of the ACh-sensitive current was not affected. Blocking of the release of intracellular Ca(2+) stores by intracellular application of heparin failed to inhibit the ACh-sensitive current. Therefore, extracellular Na(+)and the inositol 1,4,5-trisphosphate (IP(3))-dependent intracellular Ca(2+)release were not involved in the activation of the ACh-sensitive current. However, the ACh-sensitive current was strongly affected by the concentration of the extracellular K(+), extracellular Ca(2+) and intracellular Mg(2+). The amplitude of the ACh- sensitive current was strongly inhibited by high concentration of extracellular K

  1. Type-II InP quantum dots in wide-bandgap InGaP host for intermediate-band solar cells (United States)

    Tayagaki, Takeshi; Sugaya, Takeyoshi


    We demonstrate type-II quantum dots (QDs) with long carrier lifetimes in a wide-bandgap host as a promising candidate for intermediate-band solar cells. Type-II InP QDs are fabricated in a wide-bandgap InGaP host using molecular beam epitaxy. Time-resolved photoluminescence measurements reveal an extremely long carrier lifetime (i.e., greater than 30 ns). In addition, from temperature-dependent PL spectra, we find that the type-II InP QDs form a negligible valence band offset and conduction band offset of ΔEc ≈ 0.35 eV in the InGaP host. Such a type-II confinement potential for InP/InGaP QDs has a significant advantage for realizing efficient two-step photon absorption and suppressed carrier capture in QDs via Auger relaxation.

  2. Persistence of collagen type II-specific T-cell clones in the synovial membrane of a patient with rheumatoid arthritis

    Energy Technology Data Exchange (ETDEWEB)

    Londei, M.; Savill, C.M.; Verhoef, A.; Brennan, F.; Leech, Z.A.; Feldmann, M. (Charing Cross Sunley Research Centre, London (England)); Duance, V. (Bristol Laboratory (England)); Maini, R.N. (Kennedy Institute of Rheumatology, London (England))


    Rheumatoid arthritis is an autoimmune disease characterized by T-cell infiltration of the synovium of joints. Analysis of the phenotype and antigen specificity of the infiltrating cells may thus provide insight into the pathogenesis of rheumatoid arthritis. T cells were cloned with interleukin 2, a procedure that selects for in vivo-activated cells. All clones had the CD4 CDW29 phenotype. Their antigen specificity was tested by using a panel of candidate joint autoantigens. Four of 17 reacted against autologous blood mononuclear cells. Two clones proliferated in response to collagen type II. After 21 months, another set of clones was derived from synovial tissue of the same joint. One of eight clones tested showed a strong proliferative response against collagen type II. The uncloned synovial T cells of a third operation from another joint also responded to collagen type II. The persistence of collagen type II-specific T cells in active rheumatoid joints over a period of 3 years suggests that collagen type II could be one of the autoantigens involved in perpetuating the inflammatory process in rheumatoid arthritis.

  3. Comparison of Insulin Expression Levels in White Blood Cells of infants with and without Family History of Type II Diabetes

    Directory of Open Access Journals (Sweden)

    Reza Mazhari


    Full Text Available Background: Type II diabetes is known as one of the most important, prevalent, and expensive diseases of mankind. Late diagnosis and subsequent delayed initiation of treatment or surveillance of patients create a variety of problems for affected individuals. This has raised increasing concerns for public health authorities throughout the world. In the current study, we aimed to find a new approach for early identification of high-risk individuals at initial months of their life. This allows us to take preventive measures as early as possible.Materials and Methods: In our study, 102 infants - from one to six months - were selected and placed in two case and control groups. The case group contained 52 babies with at least one of their parents identified as a type II diabetic patient. The control group comprised 50 babies with no family history of type II diabetes in paternal and maternal first-degree relatives. Afterwards, the expression level of insulin gene was analyzed in white blood cells of both groups. Information related to infants - referred to outpatient and inpatient wards of three main pediatric hospitals placed in Tehran - and their parents were collected through questionnaires within a two-year period. The study inclusion criteria for infants were confirmed type II diabetes in at least one of their parents, the absence of any metabolic disorder, and the absence of any disturbing vital signs. After drawing 2 ml of babies’ peripheral blood, total RNA of white blood cells (WBC was extracted, and used for cDNA synthesis. Real-Time PCR was then applied to quantitatively evaluate the expression levels of insulin gene. The results of Real-Time PCR were statistically analyzed by non-parametric tests of Mann-Whitney and Kruskal-Wallis.Results: The expression of insulin gene was observed in white blood cells of all samples. However, there was a significant difference in expression levels between case and control groups (p<0.05. There was a

  4. Involvement of the autophagy pathway in trafficking of Mycobacterium tuberculosis bacilli through cultured human type II epithelial cells. (United States)

    Fine, Kari L; Metcalfe, Maureen G; White, Elizabeth; Virji, Mumtaz; Karls, Russell K; Quinn, Frederick D


    Interactions between Mycobacterium tuberculosis bacilli and alveolar macrophages have been extensively characterized, while similar analyses in epithelial cells have not been performed. In this study, we microscopically examined endosomal trafficking of M. tuberculosis strain Erdman in A549 cells, a human type II pneumocyte cell line. Immuno-electron microscopic (IEM) analyses indicate that M. tuberculosis bacilli are internalized to a compartment labelled first with Rab5 and then with Rab7 small GTPase proteins. This suggests that, unlike macrophages, M. tuberculosis bacilli traffic to late endosomes in epithelial cells. However, fusion of lysosomes with the bacteria-containing compartment appears to be inhibited, as illustrated by IEM studies employing LAMP-2 and cathepsin-L antibodies. Examination by transmission electron microscopy and IEM revealed M. tuberculosis-containing compartments surrounded by double membranes and labelled with antibodies against the autophagy marker Lc3, providing evidence for involvement and intersection of the autophagy and endosomal pathways. Interestingly, inhibition of the autophagy pathway using 3-methyladenine improved host cell viability and decreased numbers of viable intracellular bacteria recovered after 72 h post infection. Collectively, these data suggest that trafficking patterns for M. tuberculosis bacilli in alveolar epithelial cells differ from macrophages, and that autophagy is involved this process.

  5. Nontoxic impact of PEG-coated gold nanospheres on functional pulmonary surfactant-secreting alveolar type II cells. (United States)

    Bouzas, Virginia; Haller, Thomas; Hobi, Nina; Felder, Edward; Pastoriza-Santos, Isabel; Pérez-Gil, Jesús


    The outstanding properties of gold nanoparticles (NPs) make them very attractive for biomedical applications. In particular, the inhalation route has gained considerable interest as an innovative strategy for diagnosis and treatment of pulmonary diseases. It is, therefore, important to scrutinise the potentially deleterious or side effects of NPs on lung epithelium. The present study investigates, for the first time, the impact of polyethylene glycol (PEG)-coated NPs on freshly purified primary cultures of rat alveolar type II (ATII) cells. These cells play a central role in the respiratory function of the lungs. They are responsible for synthesizing and secreting pulmonary surfactant (PS), which is required to stabilise the respiratory surface during breathing dynamics. Cytotoxicity and cellular uptake of NPs was evaluated by analysing morphology, viability and exocytotic activity of ATII cells (PS secretion). The impact of ATII cells' exposure to NPs was studied in a wide range of gold concentration with particles sizes of 15 and 100 nm. The results show that PEG-coated NPs are very modestly internalised by ATII cells and it neither leads to detectable morphological changes nor to decreased cell viability nor to alterations in basic functional parameters such as PS secretion, even on exposure to high gold concentration (~0.2 mM) during relatively long periods of time (24-48 h).

  6. CD4+ type II NKT cells mediate ICOS and programmed death-1-dependent regulation of type 1 diabetes

    DEFF Research Database (Denmark)

    Kadri, Nadir; Korpos, Eva; Gupta, Shashank


    Type 1 diabetes (T1D) is a chronic autoimmune disease that results from T cell-mediated destruction of pancreatic ß cells. CD1d-restricted NKT lymphocytes have the ability to regulate immunity, including autoimmunity. We previously demonstrated that CD1d-restricted type II NKT cells, which carry ...

  7. An ultra fast detection method reveals strain-induced Ca(2+) entry via TRPV2 in alveolar type II cells. (United States)

    Fois, Giorgio; Wittekindt, Oliver; Zheng, Xing; Felder, Erika Tatiana; Miklavc, Pika; Frick, Manfred; Dietl, Paul; Felder, Edward


    A commonly used technique to investigate strain-induced responses of adherent cells is culturing them on an elastic membrane and globally stretching the membrane. However, it is virtually impossible to acquire microscopic images immediately after the stretch with this method. Using a newly developed technique, we recorded the strain-induced increase of the cytoplasmic Ca(2+) concentration ([Ca(2+)](c)) in rat primary alveolar type II (ATII) cells at an acquisition rate of 30ms and without any temporal delay. We can show that the onset of the mechanically induced rise in [Ca(2+)](c) was very fast (<30 ms), and Ca(2+) entry was immediately abrogated when the stimulus was withdrawn. This points at a direct mechanical activation of an ion channel. RT-PCR revealed high expression of TRPV2 in ATII cells, and silencing TRPV2, as well as blocking TRPV channels with ruthenium red, significantly reduced the strain-induced Ca(2+) response. Moreover, the usually homogenous pattern of the strain-induced [Ca(2+)](c) increase was converted into a point-like response after both treatments. Also interfering with actin/myosin and integrin binding inhibited the strain-induced increase of [Ca(2)](c). We conclude that TRPV2 participates in strain-induced Ca(2+) entry in ATII cells and suggest a direct mechanical activation of the channel that depends on FAs and actin/myosin. Furthermore, our results underline the importance of cell strain systems that allow high temporal resolution.

  8. Optimization of Streptomyces bacteriophage phi C31 integrase system to prevent post integrative gene silencing in pulmonary type II cells. (United States)

    Aneja, Manish Kumar; Geiger, Johannes; Imker, Rabea; Uzgun, Senta; Kormann, Michael; Hasenpusch, Guenther; Maucksch, Christof; Rudolph, Carsten


    phi C31 integrase has emerged as a potent tool for achieving long-term gene expression in different tissues. The present study aimed at optimizing elements of phi C31 integrase system for alveolar type II cells. Luciferase and beta-galactosidase activities were measured at different time points post transfection. 5-Aza-2'deoxycytidine (AZA) and trichostatin A (TSA) were used to inhibit DNA methyltransferase and histone deacetylase complex (HDAC) respectively. In A549 cells, expression of the integrase using a CMV promoter resulted in highest integrase activity, whereas in MLE12 cells, both CAG and CMV promoter were equally effective. Effect of polyA site was observed only in A549 cells, where replacement of SV40 polyA by bovine growth hormone (BGH) polyA site resulted in an enhancement of integrase activity. Addition of a C-terminal SV40 nuclear localization signal (NLS) did not result in any significant increase in integrase activity. Long-term expression studies with AZA and TSA, provided evidence for post-integrative gene silencing. In MLE12 cells, both DNA methylases and HDACs played a significant role in silencing, whereas in A549 cells, it could be attributed majorly to HDAC activity. Donor plasmids comprising cellular promoters ubiquitin B (UBB), ubiquitin C (UCC) and elongation factor 1 alpha (EF1 alpha) in an improved backbone prevented post-integrative gene silencing. In contrast to A549 and MLE12 cells, no silencing could be observed in human bronchial epithelial cells, BEAS-2B. Donor plasmid coding for murine erythropoietin under the EF1 alpha promoter when combined with phi C31 integrase resulted in higher long-term erythropoietin expression and subsequently higher hematocrit levels in mice after intravenous delivery to the lungs. These results provide evidence for cell specific post integrative gene silencing with C31 integrase and demonstrate the pivotal role of donor plasmid in long-term expression attained with this system.

  9. Fluorescence in situ hybridization-flow cytometry-cell sorting-based method for separation and enrichment of type I and type II methanotroph populations. (United States)

    Kalyuzhnaya, Marina G; Zabinsky, Rebecca; Bowerman, Sarah; Baker, David R; Lidstrom, Mary E; Chistoserdova, Ludmila


    A fluorescence in situ hybridization-flow cytometry (FISH/FC)-based method was optimized using artificial mixtures of pure cultures of methanotrophic bacteria. Traditional oligonucleotide probes targeting 16S rRNAs of type I (MG84/705 probe) and type II (MA450 probe) methanotrophs were labeled with fluorescein or Alexa fluor and used for FISH, followed by fluorescence-activated FC analysis and cell sorting (FACS). The method resulted in efficient separation of target cells (type I or type II methanotrophs) from the artificial mixtures. The method was then applied for detection and enrichment of type I and type II methanotroph populations from a natural sample, Lake Washington sediment. Cells were extracted from the sediment, fixed, and subjected to FISH/FC/FACS. The resulting subpopulations were analyzed by reverse transcriptase PCR surveys of 16S rRNA, pmoA (encoding a subunit of particulate methane monooxygenase), and fae (encoding formaldehyde-activating enzyme) genes. The functional gene analysis indicated specific separation of the type I and type II methanotroph populations. 16S rRNA gene analysis revealed that type I methanotrophs comprised 59% of the subpopulation separated using the type I-specific probe and that type II methanotrophs comprised 47.5% of the subpopulation separated using the type II-specific probe. Our data indicate that the FISH/FC/FACS protocol described can provide significant enrichment of microbial populations of interest from complex natural communities and that these can be used for genetic tests. We further tested the possibility of direct whole-genome amplification (WGA) from limited numbers of sorted cells, using artificial mixtures of microbes whose genome sequences are known. We demonstrated that efficient WGA can be achieved using 10(4) or more cells separated by 16S rRNA-specific FISH/FC/FACS, while fewer cells resulted in less specific WGA.

  10. A model for recombination in Type II dye-sensitized solar cells: Catechol-thiophene dyes (United States)

    Manzhos, Sergei; Segawa, Hiroshi; Yamashita, Koichi


    Recombination in dye-sensitized solar cells with direct injection is cast as internal conversion in the dye-Ti(OH) 2 complex. For catechol-thiophene dyes with 1, 2, or 3 thiophene units, the complex reproduces the previously observed dye-to-semiconductor bands. We compare the decomposition of the internal conversion rate by vibrational mode and predict a trend in recombination with the extension of conjugation, which offers an explanation for the trend in DSSC efficiency. We employ a simple model for the vibrational factors and show that they are only important in the presence of vibrational modes with ℏω⩽kT and strong electronic factors, as is the case here.

  11. Cell Wall Biology: Perspectives from Cell Wall Imaging

    Institute of Scientific and Technical Information of China (English)

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


    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.

  12. Design-based stereological analysis of the lung parenchymal architecture and alveolar type II cells in surfactant protein A and D double deficient mice

    DEFF Research Database (Denmark)

    Jung, A; Allen, L; Nyengaard, Jens Randel


    overlapping as well as distinct functions. The present study provides a design-based stereological analysis of adult mice deficient in both SP-A and SP-D (A(-)D(-)) with special emphasis on parameters characterizing alveolar architecture and surfactant-producing type II cells. Compared to wild-type, A......, but the mean volume of a single lamellar body remains constant. These results demonstrate that chronic deficiency of SP-A and SP-D in mice leads to parenchymal remodeling, type II cell hyperplasia and hypertrophy, and disturbed intracellular surfactant metabolism. The design-based stereological approach...

  13. Burkholderia mallei and Burkholderia pseudomallei stimulate differential inflammatory responses from human alveolar type II cells (ATII and macrophages.

    Directory of Open Access Journals (Sweden)

    Richard eLu


    Full Text Available Alveolar type II pneumocytes (ATII and alveolar macrophages (AM play a crucial role in the lung’s innate immune response. Burkholderia pseudomallei (BP and Burkholderia mallei (BM are facultative Gram-negative bacilli that cause melioidosis and glanders, respectively. The inhalation of these pathogens can cause lethal disease and death in humans. We sought to compare the pathogenesis of and host responses to BP and BM through contact with human primary ATII cells and monocytes-derived macrophages (MDM. We hypothesized that because BP and BM induce different disease outcomes, each pathogen would induce distinct, unique host immune responses from resident pulmonary cells. Our findings showed that BP adhered readily to ATII cells compared to BM. BP, but not BM, was rapidly internalized by macrophages where it replicated to high numbers. Further, BP induced significantly higher levels of pro-inflammatory cytokine secretion from ATII cells (IL-6, IL-8 and macrophages (IL-6, TNFα at 6h post-infection compared to BM (p<0.05. Interestingly, BM induced the anti-inflammatory cytokine, IL-10, in ATII cells and macrophages at 6h post-infection, with delayed induction of inflammatory cytokines at 24h post-infection. Because BP is flagellated and produces LPS, we confirmed that it stimulated both Toll-like receptor (TLR 4 and TLR5 via NF-κb activation while the non-flagellated BM stimulated only TLR4. These data show the differences in BP and BM pathogenicity in the lung when infecting human ATII cells and macrophages and demonstrate the ability of these pathogens to elicit distinct immune responses from resident lung cells which may open new targets for therapeutic intervention to fight against these pathogens.

  14. Expression of transforming growth factor-beta receptors types II and III within various cells in the rat periodontium. (United States)

    Gao, J; Symons, A L; Bartold, P M


    This study reports the immunohistochemical localization of TGF-beta receptor type II (T beta R-II) and type III (T beta R-III) in cells of the forming periodontal ligament (PDL) in rat first molar roots. Mandibular periodontium was obtained from 3, 6 and 12-wk-old rats. This represented tissue from the initial, pre-mature and post-mature stages of root and periodontal development, respectively. Mandibular bone chips and molar roots were used to isolate osteoblasts, fibroblasts and cementoblasts. Cells were obtained using a 2-step trypsinization and explant technique, and cultured in Dulbecco's modification of Eagle's medium (DMEM) under routine cell culture conditions. Cells were cultured on coverslips for the purpose of detecting TGF-beta receptors, and compared with whole tissue sections using the same detection method. Cells which stained positively for T beta R-II and T beta R-III on both paraffin sections and cultured cell slides were counted. Both receptors were expressed in the various periodontal tissue compartments. PDL fibroblasts, cementoblasts and osteoblasts were stained positively for T beta R-II and T beta R-III. Endothelial cells were noted to be positive for T beta R-II only. T beta R-II was more widely distributed in cells than T beta R-III, but T beta R-III was extensively localized in the extracellular matrix. Both receptors were expressed on the cell membrane and also localized in the cytoplasm. The findings for paraffin sections were consistent with the immunohistochemical staining of cultured cells. The percentage of cells which stained positively for T beta R-II was greater (approximately 85%) than that for T beta R-III (approximately 60%) in all major types of the PDL cells on both paraffin sections and cultured cell slides. Extensive location of TGF-beta receptors in both cells and extracellular matrix suggests that several binding sites are available for TGF-beta s to interact with target cells during development and following maturation

  15. p172: An alveolar type II and Clara cell specific protein with late developmental expression and upregulation by hyperoxic lung injury. (United States)

    Girod, C E; Shin, D H; Hershenson, M B; Solway, J; Dahl, R; Miller, Y E


    The epithelium of the alveolus and distal airway meets unique requirements, functioning as a gas exchange membrane and barrier to alveolar flooding by vascular contents as well as to bloodstream contamination by airborne toxins and pathogens. Gene products specifically expressed by this epithelium, notably the surfactant apoproteins, have had important clinical application. No cell surface antigen specific for alveolar type II and Clara cells has been described. We report the biochemical characterization, tissue and developmental expression, and upregulation by injury of a 172 kD protein recognized by a monoclonal antibody, 3F9, synthesized in response to immunization with freshly isolated rat alveolar type II cells. p172 is expressed in a polarized fashion by the apical surface of rat alveolar type II and Clara cells. An immunohistochemical survey of various rat tissues and organs reveals lung specificity. p172 is first detectable in rare epithelial cells at 19 days of gestation, a time when the fully differentiated alveolar type II cell is identified by the first detection of lamellar bodies. There is a dramatic increase in p172 expression just prior to birth. Hyperoxic lung injury results in increased expression of p172. The upregulation of p172 by hyperoxia and its cell-specific expression suggests an important adaptive function.

  16. Dipalmitoyl-phosphatidylcholine biosynthesis is induced by non-injurious mechanical stretch in a model of alveolar type II cells. (United States)

    Pantazi, Despoina; Kitsiouli, Eirini; Karkabounas, Athanasios; Trangas, Theoni; Nakos, George; Lekka, Marilena E


    Dipalmitoylphosphatidylcholine, (DP-PtdCho), the major phospholipid component of lung surfactant is biosynthesized via a de novo pathway, the last step of which is catalyzed by CDP-choline:cholinephosphotransferase (CPT) and two remodeling steps: a deacylation and a reacylation one, catalyzed by an acidic, Ca²⁺-independent phospholipase A₂ (aiPLA₂) and a lyso-phosphatidylcholine acyltransferase (LPCAT), respectively. The aim of our study was to investigate whether a low magnitude, non-injurious static mode of mechanical stretch can induce phosphatidylcholine (PtdCho) biosynthesis and its remodeling to DP-PtdCho in the A549 cell-line, a model of alveolar type II cells. The deformation of A549 cells did not cause any release of lactate dehydrogenase, or phospholipids into the cell culture supernatants. An increase in PtdCho levels was observed after 1 h of static stretching, especially among the DP-PtdCho molecular species, as indicated by targeted lipidomics approach and site-directed fatty acyl-chain analysis. Moreover, although sphingomyelin (CerPCho) levels were unaffected, the DP-PtdCho/CerPCho ratio increased. Induction was observed in CPT, LPCAT and aiPLA₂ enzymatic activities and gene expression. Finally, incubation of the cells with MJ33 suppressed aiPLA₂ activity and DP-PtdCho production. Our data suggest that mild static mechanical stretch can promote the biosynthesis of PtdCho and its remodeling to DP-PtdCho in lung epithelial cells. Thus, low magnitude stretch could contribute to protective mechanisms rather than to injurious ones.

  17. Type II PI4-kinases control Weibel-Palade body biogenesis and von Willebrand factor structure in human endothelial cells. (United States)

    Lopes da Silva, Mafalda; O'Connor, Marie N; Kriston-Vizi, Janos; White, Ian J; Al-Shawi, Raya; Simons, J Paul; Mössinger, Julia; Haucke, Volker; Cutler, Daniel F


    Weibel-Palade bodies (WPBs) are endothelial storage organelles that mediate the release of molecules involved in thrombosis, inflammation and angiogenesis, including the pro-thrombotic glycoprotein von Willebrand factor (VWF). Although many protein components required for WPB formation and function have been identified, the role of lipids is almost unknown. We examined two key phosphatidylinositol kinases that control phosphatidylinositol 4-phosphate levels at the trans-Golgi network, the site of WPB biogenesis. RNA interference of the type II phosphatidylinositol 4-kinases PI4KIIα and PI4KIIβ in primary human endothelial cells leads to formation of an increased proportion of short WPB with perturbed packing of VWF, as exemplified by increased exposure of antibody-binding sites. When stimulated with histamine, these cells release normal levels of VWF yet, under flow, form very few platelet-catching VWF strings. In PI4KIIα-deficient mice, immuno-microscopy revealed that VWF packaging is also perturbed and these mice exhibit increased blood loss after tail cut compared to controls. This is the first demonstration that lipid kinases can control the biosynthesis of VWF and the formation of WPBs that are capable of full haemostatic function.

  18. Quantification of beta-cell function during IVGTT in Type II and non-diabetic subjects: assessment of insulin secretion by mathematical methods

    DEFF Research Database (Denmark)

    Kjems, L L; Vølund, A; Madsbad, Sten


    AIMS/HYPOTHESIS: We compared four methods to assess their accuracy in measuring insulin secretion during an intravenous glucose tolerance test in patients with Type II (non-insulin-dependent) diabetes mellitus and with varying beta-cell function and matched control subjects. METHODS: Eight control...... subjects and eight Type II diabetic patients underwent an intravenous glucose tolerance test with tolbutamide and an intravenous bolus injection of C-peptide to assess C-peptide kinetics. Insulin secretion rates were determined by the Eaton deconvolution (reference method), the Insulin SECretion method...

  19. The coupling of acetylcholine-induced BK channel and calcium channel in guinea pig saccular type II vestibular hair cells. (United States)

    Kong, Wei-Jia; Guo, Chang-Kai; Zhang, Xiao-Wen; Chen, Xiong; Zhang, Song; Li, Guan-Qiao; Li, Zhi-Wang; Van Cauwenberge, Paul


    Molecular biological studies and electrophysiological data have demonstrated that acetylcholine (ACh) is the principal cochlear and vestibular efferent neurotransmitter among mammalians. However, the functional roles of ACh in type II vestibular hair cells (VHCs II) among mammalians are still unclear, with the exception of the well-known alpha9-containing nicotinic ACh receptor (alpha9-containing nAChR)-activated small conductance, calcium-dependent potassium current (SK) in cochlear hair cells and frog saccular hair cells. The activation of SK current was necessary for the calcium influx through the alpha9-containing nAChR. Recently, we have demonstrated that ACh-induced big conductance, calcium-dependent potassium current (BK) was present in VHCs II of the vestibular end-organ of guinea pig. In this study, the nature of calcium influx for the activation of ACh-induced BK current in saccular VHCs II of guinea pig was investigated. Following extracellular perfusion of ACh, saccular VHCs II displayed a sustained outward current, which was sensitive to iberiotoxin (IBTX). High concentration of apamin failed to inhibit the current amplitude of ACh-induced outward current. Intracellular application of Cs(+) completely abolished the current evoked by ACh. ACh-induced current was potently inhibited by nifedipine, nimodipine, Cd(2+) and Ni(2+), respectively. The inhibition potency of these four calcium channel antagonists was nimodipine>nifedipine>cadmium>nickel. The L-type Ca(2+) channels agonist, (-)-Bay-K 8644 mimicked the effect of ACh and activated an IBTX-sensitive current. In addition, partial VHCs II displayed a biphasic waveform. In conclusion, the present data showed that in the guinea pig saccular VHCs II, ACh-induced BK channel was coupled with the calcium channel, but not the receptor. The perfusion of ACh will drive the opening of calcium channels; the influx of calcium ions will then activate the BK current.

  20. Human decidua-derived mesenchymal stem cells differentiate into functional alveolar type II-like cells that synthesize and secrete pulmonary surfactant complexes.

    Directory of Open Access Journals (Sweden)

    Alejandro Cerrada

    Full Text Available Lung alveolar type II (ATII cells are specialized in the synthesis and secretion of pulmonary surfactant, a lipid-protein complex that reduces surface tension to minimize the work of breathing. Surfactant synthesis, assembly and secretion are closely regulated and its impairment is associated with severe respiratory disorders. At present, well-established ATII cell culture models are not available. In this work, Decidua-derived Mesenchymal Stem Cells (DMSCs have been differentiated into Alveolar Type II- Like Cells (ATII-LCs, which display membranous cytoplasmic organelles resembling lamellar bodies, the organelles involved in surfactant storage and secretion by native ATII cells, and accumulate disaturated phospholipid species, a surfactant hallmark. Expression of characteristic ATII cells markers was demonstrated in ATII-LCs at gene and protein level. Mimicking the response of ATII cells to secretagogues, ATII-LCs were able to exocytose lipid-rich assemblies, which displayed highly surface active capabilities, including faster interfacial adsorption kinetics than standard native surfactant, even in the presence of inhibitory agents. ATII-LCs could constitute a highly useful ex vivo model for the study of surfactant biogenesis and the mechanisms involved in protein processing and lipid trafficking, as well as the packing and storage of surfactant complexes.

  1. Human decidua-derived mesenchymal stem cells differentiate into functional alveolar type II-like cells that synthesize and secrete pulmonary surfactant complexes. (United States)

    Cerrada, Alejandro; de la Torre, Paz; Grande, Jesús; Haller, Thomas; Flores, Ana I; Pérez-Gil, Jesús


    Lung alveolar type II (ATII) cells are specialized in the synthesis and secretion of pulmonary surfactant, a lipid-protein complex that reduces surface tension to minimize the work of breathing. Surfactant synthesis, assembly and secretion are closely regulated and its impairment is associated with severe respiratory disorders. At present, well-established ATII cell culture models are not available. In this work, Decidua-derived Mesenchymal Stem Cells (DMSCs) have been differentiated into Alveolar Type II- Like Cells (ATII-LCs), which display membranous cytoplasmic organelles resembling lamellar bodies, the organelles involved in surfactant storage and secretion by native ATII cells, and accumulate disaturated phospholipid species, a surfactant hallmark. Expression of characteristic ATII cells markers was demonstrated in ATII-LCs at gene and protein level. Mimicking the response of ATII cells to secretagogues, ATII-LCs were able to exocytose lipid-rich assemblies, which displayed highly surface active capabilities, including faster interfacial adsorption kinetics than standard native surfactant, even in the presence of inhibitory agents. ATII-LCs could constitute a highly useful ex vivo model for the study of surfactant biogenesis and the mechanisms involved in protein processing and lipid trafficking, as well as the packing and storage of surfactant complexes.

  2. CCR2 and CXCR3 agonistic chemokines are differently expressed and regulated in human alveolar epithelial cells type II

    Directory of Open Access Journals (Sweden)

    Prasse Antje


    Full Text Available Abstract The attraction of leukocytes from circulation to inflamed lungs depends on the activation of both the leukocytes and the resident cells within the lung. In this study we determined gene expression and secretion patterns for monocyte chemoattractant protein-1 (MCP-1/CCL2 and T-cell specific CXCR3 agonistic chemokines (Mig/CXCL9, IP-10/CXCL10, and I-TAC/CXCL11 in TNF-α-, IFN-γ-, and IL-1β-stimulated human alveolar epithelial cells type II (AEC-II. AEC-II constitutively expressed high level of CCL2 mRNA in vitro and in situ , and released CCL2 protein in vitro . Treatment of AEC-II with proinflammatory cytokines up-regulated both CCL2 mRNA expression and release of immunoreactive CCL2, whereas IFN-γ had no effect on CCL2 release. In contrast, CXCR3 agonistic chemokines were not detected in freshly isolated AEC-II or in non-stimulated epithelial like cell line A549. IFN-γ, alone or in combination with IL-1β and TNF-α resulted in an increase in CXCL10, CXCL11, and CXCL9 mRNA expression and generation of CXCL10 protein by AEC-II or A549 cells. CXCL10 gene expression and secretion were induced in dose-dependent manner after cytokine-stimulation of AEC-II with an order of potency IFN-γ>>IL-1β ≥ TNF-α. Additionally, we localized the CCL2 and CXCL10 mRNAs in human lung tissue explants by in situ hybridization, and demonstrated the selective effects of cytokines and dexamethasone on CCL2 and CXCL10 expression. These data suggest that the regulation of the CCL2 and CXCL10 expression exhibit significant differences in their mechanisms, and also demonstrate that the alveolar epithelium contributes to the cytokine milieu of the lung, with the ability to respond to locally generated cytokines and to produce potent mediators of the local inflammatory response.

  3. Type-II Leptogenesis

    CERN Document Server

    Kim, Jihn E


    I will talk on our new theory on baryogenesis through type-II leptogenesis which is different from the well-known type-I leptogenesis. I will comment on the Jarlskog phases, $\\delta_{\\rm CKM}$ and $\\delta_{\\rm PMNS}$, in the CKM and PMNS matrices. In the type-II leptogenesis, the PMNS phase is used for Sakharov's condition on the global quantum number generation in the Universe. For this to be effective, the SU(2)$\\times$U(1) gauge symmetry must be broken during the leptogenesis epoch.

  4. Regulation of pulmonary surfactant synthesis in fetal rat type II alveolar epithelial cells by microRNA-26a. (United States)

    Zhang, Xiao-Qun; Zhang, Pan; Yang, Yang; Qiu, Jie; Kan, Qin; Liang, Hong-Lu; Zhou, Xiao-Yu; Zhou, Xiao-Guang


    Pulmonary surfactant, a unique developmentally regulated, phospholipid-rich lipoprotein, is synthesized by the type II epithelial cells (AECII) of the pulmonary alveolus, where it is stored in organelles termed lamellar bodies. The synthesis of pulmonary surfactant is under multifactorial control and is regulated by a number of hormones and factors, including glucocorticoids, prolactin, insulin, growth factors, estrogens, androgens, thyroid hormones, and catecholamines acting through beta-adrenergic receptors, and cAMP. While there is increasing evidence that microRNAs (miRNAs) are involved in the regulation of almost every cellular and physiological process, the potential role of miRNAs in the regulation of pulmonary surfactant synthesis remains unknown. miRNA-26a (miR-26a) has been predicted to target SMAD1, one of the bone morphogenetic protein (BMP) receptor downstream signaling proteins that plays a key role in differentiation of lung epithelial cells during lung development. In this study, we explored the regulation role of miR-26a in the synthesis of pulmonary surfactant. An adenoviral miR-26a overexpression vector was constructed and introduced into primary cultured fetal AECII. GFP fluorescence was observed to determinate the transfection efficiency and miR-26a levels were measured by RT-PCR. MTT was performed to analyze AECII viability. qRT-PCR and Western blotting were used to determine the mRNA and protein level of SMAD1 and surfactant-associated proteins. The results showed that miR-26a in fetal AECII was overexpressed after the transfection, and that the overexpression of miR-26a inhibited pulmonary surfactant synthesis in AECII. There was no significant change in cell proliferation. Our results further showed that overexpression of miR-26a reduced the SMAD1 expression both in mRNA and protein level in fetal AECII. These findings indicate that miR-26a regulates surfactant synthesis in fetal AECII through SMAD1.

  5. Expression of cyclin D{sub 1} during endotoxin-induced aleveolar type II cell hyperplasia in rat lung and the detection of apoptotic cells during the remodeling process

    Energy Technology Data Exchange (ETDEWEB)

    Tesfaigzi, J.; Wood, M.B.; Johnson, N.F.


    Our studies have shown that endotoxin intratracheally instilled into the rat lung induces proliferation of alveolar type II cells. In that study, the alveolar type II cells. In that study, the alveolar type II cell hyperplasia occurred 2 d after instillation of endotoxin and persisted for a further 2 d. After hyperplasia, the lung remodeled and returned to a normal state within 24-48 h. Understanding the mechanisms involved in the remodeling process of this transient hyperplasia may be useful to identify molecular changes that are altered in neoplasia. The purpose of the present study was to corroborate induction of epithelial cell hyperplasia by endotoxin and to delineate mechanisms involved in tissue remodeling after endotoxin-induced alveolar type II cell hyperplasia. In conclusion, immonostaining with cyclin D1 and cytokeratin shows that endotoxin induced epithelial cell proliferation and resulted in hyperplasia in the lung which persisted through 4 d post-instillation.

  6. DJ-1 Modulates Nuclear Erythroid 2-Related Factor-2-Mediated Protection in Human Primary Alveolar Type II Cells in Smokers. (United States)

    Bahmed, Karim; Messier, Elise M; Zhou, Wenbo; Tuder, Rubin M; Freed, Curt R; Chu, Hong Wei; Kelsen, Steven G; Bowler, Russell P; Mason, Robert J; Kosmider, Beata


    Cigarette smoke (CS) is a main source of oxidative stress and a key risk factor for emphysema, which consists of alveolar wall destruction. Alveolar type (AT) II cells are in the gas exchange regions of the lung. We isolated primary ATII cells from deidentified organ donors whose lungs were not suitable for transplantation. We analyzed the cell injury obtained from nonsmokers, moderate smokers, and heavy smokers. DJ-1 protects cells from oxidative stress and induces nuclear erythroid 2-related factor-2 (Nrf2) expression, which activates the antioxidant defense system. In ATII cells isolated from moderate smokers, we found DJ-1 expression by RT-PCR, and Nrf2 and heme oxygenase (HO)-1 translocation by Western blotting and immunocytofluorescence. In ATII cells isolated from heavy smokers, we detected Nrf2 and HO-1 cytoplasmic localization. Moreover, we found high oxidative stress, as detected by 4-hydroxynonenal (4-HNE) (immunoblotting), inflammation by IL-8 and IL-6 levels by ELISA, and apoptosis by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay in ATII cells obtained from heavy smokers. Furthermore, we detected early DJ-1 and late Nrf2 expression after ATII cell treatment with CS extract. We also overexpressed DJ-1 by adenovirus construct and found that this restored Nrf2 and HO-1 expression and induced nuclear translocation in heavy smokers. Moreover, DJ-1 overexpression also decreased ATII cell apoptosis caused by CS extract in vitro. Our results indicate that DJ-1 activates the Nrf2-mediated antioxidant defense system. Furthermore, DJ-1 overexpression can restore the impaired Nrf2 pathway, leading to ATII cell protection in heavy smokers. This suggests a potential therapeutic strategy for targeting DJ-1 in CS-related lung diseases.

  7. Quantification of beta-cell function during IVGTT in Type II and non-diabetic subjects: assessment of insulin secretion by mathematical methods

    DEFF Research Database (Denmark)

    Kjems, L L; Vølund, A; Madsbad, Sten


    AIMS/HYPOTHESIS: We compared four methods to assess their accuracy in measuring insulin secretion during an intravenous glucose tolerance test in patients with Type II (non-insulin-dependent) diabetes mellitus and with varying beta-cell function and matched control subjects. METHODS: Eight control...... subjects and eight Type II diabetic patients underwent an intravenous glucose tolerance test with tolbutamide and an intravenous bolus injection of C-peptide to assess C-peptide kinetics. Insulin secretion rates were determined by the Eaton deconvolution (reference method), the Insulin SECretion method...... (ISEC) based on population kinetic parameters as well as one-compartment and two-compartment versions of the combined model of insulin and C-peptide kinetics. To allow a comparison of the accuracy of the four methods, fasting rates and amounts of insulin secreted during the first phase (0-10 min...

  8. Obinutuzumab (GA101) for the treatment of chronic lymphocytic leukemia and other B-cell non-hodgkin's lymphomas: a glycoengineered type II CD20 antibody. (United States)

    Goede, Valentin; Klein, Christian; Stilgenbauer, Stephan


    Obinutuzumab (GA101) is a humanized, monoclonal type II CD20 antibody modified by glycoengineering. The glycoengineered Fc portion enhances the binding affinity to the FcγRIII receptor on immune effector cells, resulting in increased antibody-dependent cellular cytotoxicity and phagocytosis. In addition, the type II antibody binding characteristics of obinutuzumab to CD20 lead to an efficient induction of direct non-apoptotic cell death. Preclinical data demonstrated more efficient B-cell depletion in whole blood and superior antitumor activity in xenograft models of obinutuzumab as compared to the type I CD20 antibody rituximab. In previously untreated patients with chronic lymphocytic leukemia (CLL) and comorbidities, obinutuzumab plus chlorambucil increased response rates and prolonged progression-free survival compared with rituximab plus chlorambucil. Obinutuzumab had an acceptable and manageable safety profile, with infusion-related reactions during the first infusion as the most common adverse event. Further phase I/II clinical trials have also shown promising activity in other CD20-positive B-cell non-Hodgkin's lymphomas (NHL). Therefore, several clinical studies are planned or ongoing to investigate obinutuzumab with different combination partners in both untreated and relapsed/refractory patients with different B-cell NHL entities, which in addition to CLL include diffuse large B-cell lymphoma and follicular lymphoma. © 2015 S. Karger GmbH, Freiburg.

  9. Human YKL39 (chitinase 3-like protein 2), an osteoarthritis-associated gene, enhances proliferation and type II collagen expression in ATDC5 cells

    Energy Technology Data Exchange (ETDEWEB)

    Miyatake, Kazumasa [Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University, Tokyo (Japan); Tsuji, Kunikazu, E-mail: [International Research Center for Molecular Science in Tooth and Bone Diseases (Global Center of Excellence Program), Tokyo Medical and Dental University, Tokyo (Japan); Yamaga, Mika; Yamada, Jun; Matsukura, Yu; Abula, Kahaer [Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University, Tokyo (Japan); Sekiya, Ichiro [Section of Cartilage Regeneration, Tokyo Medical and Dental University, Tokyo (Japan); Muneta, Takeshi [Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University, Tokyo (Japan); International Research Center for Molecular Science in Tooth and Bone Diseases (Global Center of Excellence Program), Tokyo Medical and Dental University, Tokyo (Japan)


    Highlights: ► hYKL-39 expression is increased in osteoarthritic articular chondrocytes. ► To examine the molecular functions of hYKL-39 in chondrocytes, we overexpressed hYKL-39 in chondrocytic ATDC5 cells. ► hYKL-39 enhanced proliferation and colony formation in ATDC5 cells. ► hYKL-39 increased type II collagen expression in ATDC5 cells treated with chondrogenic medium. -- Abstract: Human YKL39 (chitinase 3-like protein 2/CHI3L2) is a secreted 39 kDa protein produced by articular chondrocytes and synoviocytes. Recent studies showed that hYKL-39 expression is increased in osteoarthritic articular chondrocytes suggesting the involvement of hYKL-39 in the progression of osteoarthritis (OA). However little is known regarding the molecular function of hYKL-39 in joint homeostasis. Sequence analyses indicated that hYKL-39 has significant identity with the human chitotorisidase family molecules, although it is considered that hYKL-39 has no enzymatic activity since it lacks putative chitinase catalytic motif. In this study, to examine the molecular function of hYKL-39 in chondrocytes, we overexpressed hYKL-39 in ATDC5 cells. Here we report that hYKL-39 enhances colony forming activity, cell proliferation, and type II collagen expression in these cells. These data suggest that hYKL-39 is a novel growth and differentiation factor involved in cartilage homeostasis.

  10. Isolation of the Cell Wall. (United States)

    Canut, Hervé; Albenne, Cécile; Jamet, Elisabeth


    This chapter describes a method allowing the purification of the cell wall for studying both polysaccharides and proteins. The plant primary cell wall is mainly composed of polysaccharides (90-95 % in mass) and of proteins (5-10 %). At the end of growth, specialized cells may synthesize a lignified secondary wall composed of polysaccharides (about 65 %) and lignin (about 35 %). Due to its composition, the cell wall is the cellular compartment having the highest density and this property is used for its purification. It plays critical roles during plant development and in response to environmental constraints. It is largely used in the food and textile industries as well as for the production of bioenergy. All these characteristics and uses explain why its study as a true cell compartment is of high interest. The proposed method of purification can be used for large amount of material but can also be downscaled to 500 mg of fresh material. Tools for checking the quality of the cell wall preparation, such as protein analysis and microscopy observation, are also provided.

  11. Deleted in malignant brain tumors 1 (DMBT1) elicits increased VEGF and decreased IL-6 production in type II lung epithelial cells

    DEFF Research Database (Denmark)

    Müller, Hanna; Nagel, Christian; Weiss, Christel


    between VEGF and IL-6 levels to DMBT1 expression in the lungs of preterm and term infants and in lung epithelial cells in vitro. METHODS: We examined by ELISA VEGF levels in 120 tracheal aspirates of 57 preterm and term infants and tested for correlation with different perinatal factors as well...... as with DMBT1 levels. To examine the effect of DMBT1 on VEGF and IL-6 expression we compared type II lung epithelial A549 cells stably transfected with a DMBT1 expression plasmid (DMBT1+ cells) to A549 cells stably transfected with an empty expression plasmid (DMBT1- cells). The concentrations of VEGF and IL-6...... that DMBT1 promotes VEGF and suppresses IL-6 production in alveolar tissues, which could point to DMBT1 having a possible role in the transition from inflammation to regeneration and being a potentially useful clinical marker....

  12. Anti-Müllerian hormone inhibits growth of AMH type II receptor-positive human ovarian granulosa cell tumor cells by activating apoptosis. (United States)

    Anttonen, Mikko; Färkkilä, Anniina; Tauriala, Hanna; Kauppinen, Marjut; Maclaughlin, David T; Unkila-Kallio, Leila; Bützow, Ralf; Heikinheimo, Markku


    Ovarian granulosa cell tumors (GCTs) are sex cord stromal tumors that constitute 3-5% of all ovarian cancers. GCTs usually present with an indolent course but there is a high risk of recurrence, which associates with increased mortality, and targeted treatments would be desirable. Anti-Müllerian hormone (AMH), a key factor regulating sexual differentiation of the reproductive organs, has been implicated as a growth inhibitor in ovarian cancer. GCTs and normal granulosa cells produce AMH, but its expression in large GCTs is usually downregulated. Further, as the lack of specific AMH-signaling pathway components leads to GCT development in mice, we hypothesized that AMH inhibits growth of GCTs. Utilizing a large panel of human GCT tissue samples, we found that AMH type I receptors (ALK2, ALK3 and ALK6) and type II receptor (AMHRII), as well as their downstream effectors Smad1/5, are expressed and active in GCTs. AMHRII expression was detected in the vast majority (96%) of GCTs and correlated with AMH mRNA and protein expression. AMH mRNA level was low in large GCTs, confirming previous findings on low-AMH protein expression in large human as well as mouse GCTs. To study the functional role of AMH in this peculiar ovarian cancer, we utilized a human GCT cell line (KGN) and 10 primary GCT cell cultures. We found that the AMH-Smad1/5-signaling pathway was active in these cells, and that exogenous AMH further activated Smad1/5 in KGN cells. Furthermore, AMH treatment reduced the number of KGN cells and primary GCT cells, with increasing amounts of AMH leading to augmented activation of caspase-3 and subsequent apoptosis. All in all, these data support the premise that AMH is a growth inhibitor of GCTs.

  13. Catalysts of plant cell wall loosening


    Cosgrove, Daniel J.


    The growing cell wall in plants has conflicting requirements to be strong enough to withstand the high tensile forces generated by cell turgor pressure while selectively yielding to those forces to induce wall stress relaxation, leading to water uptake and polymer movements underlying cell wall expansion. In this article, I review emerging concepts of plant primary cell wall structure, the nature of wall extensibility and the action of expansins, family-9 and -12 endoglucanases, family-16 xyl...

  14. Neuregulin 1 Type II-ErbB Signaling Promotes Cell Divisions Generating Neurons from Neural Progenitor Cells in the Developing Zebrafish Brain. (United States)

    Sato, Tomomi; Sato, Fuminori; Kamezaki, Aosa; Sakaguchi, Kazuya; Tanigome, Ryoma; Kawakami, Koichi; Sehara-Fujisawa, Atsuko


    Post-mitotic neurons are generated from neural progenitor cells (NPCs) at the expense of their proliferation. Molecular and cellular mechanisms that regulate neuron production temporally and spatially should impact on the size and shape of the brain. While transcription factors such as neurogenin1 (neurog1) and neurod govern progression of neurogenesis as cell-intrinsic mechanisms, recent studies show regulatory roles of several cell-extrinsic or intercellular signaling molecules including Notch, FGF and Wnt in production of neurons/neural progenitor cells from neural stem cells/radial glial cells (NSCs/RGCs) in the ventricular zone (VZ). However, it remains elusive how production of post-mitotic neurons from neural progenitor cells is regulated in the sub-ventricular zone (SVZ). Here we show that newborn neurons accumulate in the basal-to-apical direction in the optic tectum (OT) of zebrafish embryos. While neural progenitor cells are amplified by mitoses in the apical ventricular zone, neurons are exclusively produced through mitoses of neural progenitor cells in the sub-basal zone, later in the sub-ventricular zone, and accumulate apically onto older neurons. This neurogenesis depends on Neuregulin 1 type II (NRG1-II)-ErbB signaling. Treatment with an ErbB inhibitor, AG1478 impairs mitoses in the sub-ventricular zone of the optic tectum. Removal of AG1478 resumes sub-ventricular mitoses without precedent mitoses in the apical ventricular zone prior to basal-to-apical accumulation of neurons, suggesting critical roles of ErbB signaling in mitoses for post-mitotic neuron production. Knockdown of NRG1-II impairs both mitoses in the sub-basal/sub-ventricular zone and the ventricular zone. Injection of soluble human NRG1 into the developing brain ameliorates neurogenesis of NRG1-II-knockdown embryos, suggesting a conserved role of NRG1 as a cell-extrinsic signal. From these results, we propose that NRG1-ErbB signaling stimulates cell divisions generating neurons from

  15. PACAP inhibits β-cell mass expansion in a mouse model of type II diabetes: persistent suppressive effects on islet density

    Directory of Open Access Journals (Sweden)

    Hiroaki eInoue


    Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP is a potent insulinotropic G-protein-coupled receptor ligand, for which morphoregulative roles in pancreatic islets have recently been suggested. Here, we evaluated the effects of pancreatic overexpression of PACAP on morphometric changes of islets in a severe type II diabetes model. Following cross-breeding of obese-diabetic model KKAy mice with mice overexpressing PACAP in their pancreatic β-cells, the resulting KKAy mice with or without PACAP transgene (PACAP/+:Ay/+ or Ay/+ mice were fed with a high-fat diet up to the age of 11 months. Pancreatic sections from 5 and 11 month old littermates were examined. Histomorphometric analyses revealed significant suppression of islet mass expansion in PACAP/+:Ay/+ mice compared with Ay/+ mice at 11 months, but no significant difference between PACAP/+ and +/+ (wild-type mice, as previously reported. The suppressed islet mass in PACAP/+:Ay/+ mice was due to a decrease in islet density but not islet size. In addition, the density of tiny islets (<0.001 mm2 and of insulin-positive clusters in ductal structures were markedly decreased in PACAP/+:Ay/+ mice compared with Ay/+ mice at 5 months of age. In contrast, PACAP overexpression caused no significant effects on the level of aldehyde-fuchsin reagent staining (a measure of β-cell granulation or the volume and localization of glucagon-positive cells in the pancreas. These results support previously reported inhibitory effects of PACAP on pancreatic islet mass expansion, and suggest it has persistent suppressive effects on pancreatic islet density which may be related with ductal cell-associated islet neogenesis in type II diabetes.

  16. Long Term Culture of the A549 Cancer Cell Line Promotes Multilamellar Body Formation and Differentiation towards an Alveolar Type II Pneumocyte Phenotype (United States)

    Cooper, James Ross; Abdullatif, Muhammad Bilal; Burnett, Edward C.; Kempsell, Karen E.; Conforti, Franco; Tolley, Howard; Collins, Jane E.; Davies, Donna E.


    Pulmonary research requires models that represent the physiology of alveolar epithelium but concerns with reproducibility, consistency and the technical and ethical challenges of using primary or stem cells has resulted in widespread use of continuous cancer or other immortalized cell lines. The A549 ‘alveolar’ cell line has been available for over four decades but there is an inconsistent view as to its suitability as an appropriate model for primary alveolar type II (ATII) cells. Since most work with A549 cells involves short term culture of proliferating cells, we postulated that culture conditions that reduced proliferation of the cancer cells would promote a more differentiated ATII cell phenotype. We examined A549 cell growth in different media over long term culture and then used microarray analysis to investigate temporal regulation of pathways involved in cell cycle and ATII differentiation; we also made comparisons with gene expression in freshly isolated human ATII cells. Analyses indicated that long term culture in Ham’s F12 resulted in substantial modulation of cell cycle genes to result in a quiescent population of cells with significant up-regulation of autophagic, differentiation and lipidogenic pathways. There were also increased numbers of up- and down-regulated genes shared with primary cells suggesting adoption of ATII characteristics and multilamellar body (MLB) development. Subsequent Oil Red-O staining and Transmission Electron Microscopy confirmed MLB expression in the differentiated A549 cells. This work defines a set of conditions for promoting ATII differentiation characteristics in A549 cells that may be advantageous for studies with this cell line. PMID:27792742

  17. Gliotoxin promotes Aspergillus fumigatus internalization into type II human pneumocyte A549 cells by inducing host phospholipase D activation. (United States)

    Jia, Xiaodong; Chen, Fangyan; Pan, Weihua; Yu, Rentao; Tian, Shuguang; Han, Gaige; Fang, Haiqin; Wang, Shuo; Zhao, Jingya; Li, Xianping; Zheng, Dongyu; Tao, Sha; Liao, Wanqing; Han, Xuelin; Han, Li


    The internalization of Aspergillus fumigatus into lung epithelial cells is critical for the infection process in the host. Gliotoxin is the most potent toxin produced by A. fumigatus. However, its role in A. fumigatus internalization into the lung epithelial cells is still largely unknown. In the present study, the deletion of the gliP gene regulating the production of gliotoxin in A. fumigatus suppressed the internalization of conidia into the A549 lung epithelial cells, and this suppression could be rescued by the exogenous addition of gliotoxin. At lower concentrations, gliotoxin enhanced the internalization of the conidia of A. fumigatus into A549 cells; in contrast, it inhibited the phagocytosis of J774 macrophages in a dose-dependent manner. Under a concentration of 100 ng/ml, gliotoxin had no effect on A549 cell viability but attenuated ROS production in a dose-dependent manner. Gliotoxin significantly stimulated the phospholipase D activity in the A549 cells at a concentration of 50 ng/ml. This stimulation was blocked by the pretreatment of host cells with PLD1- but not PLD2-specific inhibitor. Morphological cell changes induced by gliotoxin were observed in the A549 cells accompanying with obvious actin cytoskeleton rearrangement and a moderate alteration of phospholipase D distribution. Our data indicated that gliotoxin might be responsible for modulating the A. fumigatus internalization into epithelial cells through phospholipase D1 activation and actin cytoskeleton rearrangement.

  18. Type I (CD64) and type II (CD32) Fc gamma receptor-mediated phagocytosis by human blood dendritic cells. (United States)

    Fanger, N A; Wardwell, K; Shen, L; Tedder, T F; Guyre, P M


    Three classes of Fc receptors for IgG, Fc gamma RI (CD64), Fc gamma RII (CD32), and Fc gamma RIII (CD16), are expressed on blood leukocytes. Although Fc gamma R are important phagocytic receptors on phagocytes, most reports suggest that dendritic cells lack Fc gamma R-mediated phagocytosis and express significant levels of only CD32. We now report that phagocytically active forms of both CD64 and CD32 are expressed significantly on at least one subset of human blood dendritic cells. Countercurrent elutriation and magnetic bead selection were used to rapidly enrich subsets of blood dendritic cells (CD33brightCD14-HLA-DRbrightCD83-) and monocytes (CD33brightCD14brightHLA-DRdimCD83-). Upon culture for 2 days, dendritic cells became CD83-positive and markedly increased HLA-DR expression, whereas monocytes did not express CD83 and exhibited reduced levels of HLA-DR. Constitutive CD64 expression was identified on this circulating dendritic cell population, but at a lower level than on monocytes. CD64 expression by dendritic cells and monocytes did not decrease during 2 days in culture, and was up-regulated on both cell types following incubation with IFN-gamma. Freshly isolated blood dendritic cells performed CD64- and CD32-mediated phagocytosis, although at a lower level than monocytes. Dendritic cells generated by culture of adherent mononuclear cells in granulocyte-macrophage CSF and IL-4 also up-regulated CD64 following IFN-gamma stimulation, and mediated CD64-dependent phagocytosis. These results indicate that both CD64 and CD32 expressed on blood dendritic cells may play a role in uptake of foreign particles and macromolecules through a phagocytic mechanism before trafficking to T cell-reactive areas.

  19. High value of the radiobiological parameter Dq correlates to expression of the transforming growth factor beta type II receptor in a panel of small cell lung cancer cell lines

    DEFF Research Database (Denmark)

    Hougaard, S; Krarup, M; Nørgaard, P;


    Our panel of SCLC cell lines have previously been examined for their radiobiological characteristics and sensitivity to treatment with TGF beta 1. In this study we examined the possible correlations between radiobiological parameters and the expression of the TGF beta type II receptor (TGF beta-r...... role for the repair of radiation induced DNA damage in SCLC....

  20. Impact of cell type and epitope tagging on heterologous expression of G protein-coupled receptor: a systematic study on angiotensin type II receptor.

    Directory of Open Access Journals (Sweden)

    Lili Jiang

    Full Text Available Despite heterologous expression of epitope-tagged GPCR is widely adopted for functional characterization, there is lacking of systematic analysis of the impact of expression host and epitope tag on GPCR expression. Angiotensin type II (AT2 receptor displays agonist-dependent and -independent activities, coupling to a spectrum of signaling molecules. However, consensus has not been reached on the subcellular distributions, signaling cascades and receptor-mediated actions. To examine the contributions of host cell and epitope tag on receptor expression and activity, epitope-tagged AT2 receptor variants were transiently or stably expressed in HEK293, CHO-K1 and PC12 cells. The epitope-tagged AT2 receptor variants were detected both on the cell membrane and in the perinuclear region. In transiently transfected HEK293 cells, Myc-AT2 existed predominantly as monomer. Additionally, a ladder of ubiquitinated AT2 receptor proteins was detected. By contrast, stably expressed epitope-tagged AT2 receptor variants existed as both monomer and high molecular weight complexes, and the latter was enriched in cell surface. Glycosylation promoted cell surface expression of Myc-AT2 but had no effect on AT2-GFP in HEK293 cells. In cells that stably expressed Myc-AT2, serum starvation induced apoptosis in CHO-K1 cells but not in HEK293 or PC12 cells. Instead, HEK293 and PC12 cells stably expressing Myc-AT2 exhibited partial cell cycle arrest with cells accumulating at G1 and S phases, respectively. Taken together, these results suggest that expression levels, subcellular distributions and ligand-independent constitutive activities of AT2 receptor were cell type-dependent while posttranslational processing of nascent AT2 receptor protein was modulated by epitope tag and mode of expression.

  1. Type I and Type II Interferon Coordinately Regulate Suppressive Dendritic Cell Fate and Function during Viral Persistence.

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    Cameron R Cunningham


    Full Text Available Persistent viral infections are simultaneously associated with chronic inflammation and highly potent immunosuppressive programs mediated by IL-10 and PDL1 that attenuate antiviral T cell responses. Inhibiting these suppressive signals enhances T cell function to control persistent infection; yet, the underlying signals and mechanisms that program immunosuppressive cell fates and functions are not well understood. Herein, we use lymphocytic choriomeningitis virus infection (LCMV to demonstrate that the induction and functional programming of immunosuppressive dendritic cells (DCs during viral persistence are separable mechanisms programmed by factors primarily considered pro-inflammatory. IFNγ first induces the de novo development of naive monocytes into DCs with immunosuppressive potential. Type I interferon (IFN-I then directly targets these newly generated DCs to program their potent T cell immunosuppressive functions while simultaneously inhibiting conventional DCs with T cell stimulating capacity. These mechanisms of monocyte conversion are constant throughout persistent infection, establishing a system to continuously interpret and shape the immunologic environment. MyD88 signaling was required for the differentiation of suppressive DCs, whereas inhibition of stimulatory DCs was dependent on MAVS signaling, demonstrating a bifurcation in the pathogen recognition pathways that promote distinct elements of IFN-I mediated immunosuppression. Further, a similar suppressive DC origin and differentiation was also observed in Mycobacterium tuberculosis infection, HIV infection and cancer. Ultimately, targeting the underlying mechanisms that induce immunosuppression could simultaneously prevent multiple suppressive signals to further restore T cell function and control persistent infections.

  2. A Review of Obinutuzumab (GA101), a Novel Type II Anti-CD20 Monoclonal Antibody, for the Treatment of Patients with B-Cell Malignancies. (United States)

    Tobinai, Kensei; Klein, Christian; Oya, Naoko; Fingerle-Rowson, Günter


    Obinutuzumab (GA101) is a novel, type II, glycoengineered, humanized anti-CD20 monoclonal antibody that has been developed to address the need for new therapeutics with improved efficacy in patients with lymphocytic leukemia and lymphoma of B-cell origin. Obinutuzumab has a distinct mode of action relative to type I anti-CD20 antibodies, such as rituximab, working primarily by inducing direct cell death and antibody-dependent cell-mediated cytotoxicity. Obinutuzumab is under investigation in a wide-ranging program of clinical trials in patients with B-cell malignancies. Efficacy as monotherapy has been reported in patients with relapsed/refractory indolent and aggressive non-Hodgkin lymphoma (NHL) and in chronic lymphocytic leukemia (CLL) of B-cell origin. Improved outcomes have also been noted when obinutuzumab is added to chemotherapy in patients with B-cell NHL, and superiority over rituximab has been reported with combination therapy in patients with CLL. Ongoing research is focusing on developing options for chemotherapy-free treatment and on new combinations of obinutuzumab with novel targeted agents.

  3. Enhanced antigen uptake by dendritic cells induced by the B pentamer of the type II heat-labile enterotoxin LT-IIa requires engagement of TLR2. (United States)

    Lee, Chang Hoon; Nawar, Hesham F; Mandell, Lorrie; Liang, Shuang; Hajishengallis, George; Connell, Terry D


    The potent mucosal adjuvant properties of the type II heat-labile enterotoxin LT-IIa of Escherichia coli are dependent upon binding of the B pentamer of the enterotoxin (LT-IIa-B(5)) to ganglioside receptors on immunocompetent cells. To evaluate the immunomodulatory activities of LT-IIa-B(5), in vitro experiments employing bone marrow-derived dendritic cells (BMDC) were performed. Uptake of OVA-FITC, a model antigen (Ag), was enhanced by treatment of BMDC with LT-IIa-B5, but not by treatment of cells with the B pentamer of cholera toxin (CTB). Expression of co-stimulatory molecules (CD40, CD80, CD86, and MHC-II) and cytokines (IL-12p40, TNF-alpha, and IFN-gamma) was increased in BMDC treated with LT-IIa-B(5). The capacity of LT-IIa-B(5) to enhance Ag uptake and to induce expression of co-stimulatory receptors and cytokines by BMDC was dependent upon expression of TLR2 by the cell. Increased Ag uptake induced by LT-IIa-B(5) was correlated with increased Ag-specific proliferation of CD4(+) T cells in an in vitro syngeneic DO11.10 CD4(+) T cell proliferation assay. These experiments confirm that LT-IIa-B(5) exhibits potent immunomodulatory properties which may be exploitable as a non-toxic mucosal adjuvant.

  4. A Novel Approach for Ovine Primary Alveolar Epithelial Type II Cell Isolation and Culture from Fresh and Cryopreserved Tissue Obtained from Premature and Juvenile Animals. (United States)

    Marcinkiewicz, Mariola M; Baker, Sandy T; Wu, Jichuan; Hubert, Terrence L; Wolfson, Marla R


    The in vivo ovine model provides a clinically relevant platform to study cardiopulmonary mechanisms and treatments of disease; however, a robust ovine primary alveolar epithelial type II (ATII) cell culture model is lacking. The objective of this study was to develop and optimize ovine lung tissue cryopreservation and primary ATII cell culture methodologies for the purposes of dissecting mechanisms at the cellular level to elucidate responses observed in vivo. To address this, we established in vitro submerged and air-liquid interface cultures of primary ovine ATII cells isolated from fresh or cryopreserved lung tissues obtained from mechanically ventilated sheep (128 days gestation-6 months of age). Presence, abundance, and mRNA expression of surfactant proteins was assessed by immunocytochemistry, Western Blot, and quantitative PCR respectively on the day of isolation, and throughout the 7 day cell culture study period. All biomarkers were significantly greater from cells isolated from fresh than cryopreserved tissue, and those cultured in air-liquid interface as compared to submerged culture conditions at all time points. Surfactant protein expression remained in the air-liquid interface culture system while that of cells cultured in the submerged system dissipated over time. Despite differences in biomarker magnitude between cells isolated from fresh and cryopreserved tissue, cells isolated from cryopreserved tissue remained metabolically active and demonstrated a similar response as cells from fresh tissue through 72 hr period of hyperoxia. These data demonstrate a cell culture methodology using fresh or cryopreserved tissue to support study of ovine primary ATII cell function and responses, to support expanded use of biobanked tissues, and to further understanding of mechanisms that contribute to in vivo function of the lung.

  5. Effect of amygdalin on the proliferation of hyperoxia-exposed type II alveolar epithelial cells isolated from premature rat. (United States)

    Zhu, Huaping; Chang, Liwen; Li, Wenbin; Liu, Hanchu


    The pathogenesis of hyperoxia lung injury and the mechanism of amygdalin on type 2 alveolar epithelial cells (AEC2) isolated from premature rat lungs in vitro were investigated. AEC2 were obtained by primary culture from 20-days fetal rat lung and hyperoxia-exposed cell model was established. Cell proliferating viability was examined by MTT assay after treatment of amygdalin at various concentrations. DNA content and the proliferating cell nuclear antigen (PCNA) protein expression of AEC2 were measured by using flow cytometry and immunocytochemistry respectively after 24 h of hyperoxia exposure or amygdalin treatment. The results showed that hyperoxia inhibited the proliferation and decreased PCNA protein expression in A-EC2 of premature rat in vitro. Amygdalin at the concentration range of 50-200 micromol/L stimulated the proliferation of AEC2 in a dose-dependent manner, however, 400 micromol/L amygdalin inhibited the proliferation of AEC2. Amygdalin at the concentration of 200 micromol/L played its best role in facilitating proliferation of AEC2s in vitro and could partially ameliorated the changes of proliferation in hyperoxia exposed AEC2 of premature rat. It has been suggested that hyperoxia inhibited the proliferation of AEC2s of premature rat, which may contribute to hyperoxia lung injury. Amygdalin may play partial protective role in hyperoxia-induced lung injury.

  6. Shape dynamics of growing cell walls

    CERN Document Server

    Banerjee, Shiladitya; Dinner, Aaron R


    We introduce a general theoretical framework to study the shape dynamics of actively growing and remodeling surfaces. Using this framework we develop a physical model for growing bacterial cell walls and study the interplay of cell shape with the dynamics of growth and constriction. The model allows us to derive constraints on cell wall mechanical energy based on the observed dynamics of cell shape. We predict that exponential growth in cell size requires a constant amount of cell wall energy to be dissipated per unit volume. We use the model to understand and contrast growth in bacteria with different shapes such as spherical, ellipsoidal, cylindrical and toroidal morphologies. Coupling growth to cell wall constriction, we predict a discontinuous shape transformation, from partial constriction to cell division, as a function of the chemical potential driving cell-wall synthesis. Our model for cell wall energy and shape dynamics relates growth kinetics with cell geometry, and provides a unified framework to d...

  7. The Role of Neonatal Carnitine Palmitoyl Transferase Deficiency Type II on Proliferation of Neuronal Progenitor Cells and Layering of the Cerebral Cortex in the Developing Brain

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    Heepeel Chang


    Full Text Available Neonatal Carnitine Palmitoyl Transferase Deficiency Type II, characterized by the absence of CPT II enzyme, is one of the lethal disorders of mitochondrial fatty acid oxidation. CPT II regulates the conversion of long chain fatty acids, so that its product, acyl-CoA esters, can enter the Krebs cycle and generate energy. Neonatal mutations of CPT II lead to severe disruption of the metabolism of long-chain fatty acids and result in dysmorphic features, cystic renal dysplasia, and neuronal migration defects. Examination of the brain from an approximately 15-week gestation human fetus with CPT II deficiency revealed premature formation of cerebral cortical gyri and sulci and significantly lower levels of neuronal cell proliferation in the ventricular and subventricular zones as compared to the reference cases. We used immunohistochemical markers to further characterize the effect of CPT II deficiency on progenitor cell proliferation and layering of neurons. These studies demonstrated a premature generation of layer 5 cortical neurons. In addition, both the total number and percentage of progenitor cells proliferating in the ventricular zone were markedly reduced in the CPT II case in comparison to a reference case. Our results indicate that CPT II deficiency alters the normal program of cellular proliferation and differentiation in the cortex, with early differentiation of progenitor cells associated with premature cortical maturation.

  8. Mild stretch activates cPLA2 in alveolar type II epithelial cells independently through the MEK/ERK and PI3K pathways. (United States)

    Letsiou, Eleftheria; Kitsiouli, Ei; Nakos, George; Lekka, Marilena E


    Alveolar epithelial type II cells (AT II) in which lung surfactant synthesis and secretion take place, are subjected to low magnitude stretch during normal breathing. The aim of the study was to explore the effect of mild stretch on phospholipase A(2) (PLA(2)) activation, an enzyme known to be involved in surfactant secretion. In A549 cells (a model of AT II cells), we showed, using a fluorometric assay, that stretch triggers an increase of total PLA(2) activity. Western blot experiments revealed that the cytosolic isoform cPLA(2) is rapidly phosphorylated under stretch, in addition to a modest increase in cPLA(2) mRNA levels. Treatment of A549 cells with selective inhibitors of the MEK/ERK pathway significantly attenuated the stretch-induced cPLA(2) phosphorylation. A strong interaction of cPLA(2) and pERK enzymes was demonstrated by immunoprecipitation. We also found that inhibition of PI3K pathway attenuated cPLA(2) activation after stretch, without affecting pERK levels. Our results suggest that low magnitude stretch can induce cPLA(2) phosphorylation through the MEK/ERK and PI3K-Akt pathways, independently.

  9. Effects of thiazinamium chloride on surfactant production in primary cultures of type II cells isolated from adult rat lung

    Energy Technology Data Exchange (ETDEWEB)

    Gilfillan, A.M.; Lewis, A.J.; Rooney, S.A.


    Thiazinamium-Cl (T), an analog of promethazine (P), has antiasthmatic activity that may be related to its antihistaminic and anticholinergic actions or its ability to inhibition thromboxane synthesis. To assess phosphatidylcholine (PC) secretion, freshly isolated cells were preincubated with /sup 3/H-choline for 18 h and then incubated in fresh medium +/- test agent for 90 min when /sup 3/H-PC in the cells and medium was measured. PC synthesis was similarly assessed during the latter incubation period by measuring the rate of /sup 3/H-choline incorporation into cellular PC. 10/sup -6/ M T stimulated PC secretion by 46% from 0.92 +/- 0.05 (PC in the medium as % of total) to 1.34 +/- 0.08 (P < 0.01, n = 6). The EC/sub 50/ was 2.9 x 10/sup -8/ M. In comparison, terbutaline (Tb) maximally stimulated PC secretion by 108% at 10/sup -5/ M (P < 0.001, n = 13) and isoproterenol (I) by 112% at 10/sup -7/ M (P < 0.01, n = 5). The EC/sub 50/ values for Tb and I were 1.6 x 10/sup -7/ M and 3.2 x 10/sup -9/ M, respectively. T did not stimulate PC synthesis nor increase lactate dehydrogenase release. Thus, the effect on secretion was not due to increased synthesis or to cell injury. The effect of T on PC secretion was mimicked by 10/sup -6/M P (48% stimulation, P < 0.01, n = 7) and by 10/sup -5/M pyrilamine, a structurally dissimilar antihistamine, (52% stimulation, P < 0.002, n = 7). The effects of T or pyrilamine and of Tb were additive suggesting a different mechanism of action. Although histamine did not inhibit PC secretion it may play a physiologic role in its regulation.

  10. Enhanced expression of the type II transforming growth factor beta receptor in human pancreatic cancer cells without alteration of type III receptor expression. (United States)

    Friess, H; Yamanaka, Y; Büchler, M; Berger, H G; Kobrin, M S; Baldwin, R L; Korc, M


    We have recently found that human pancreatic adenocarcinomas exhibit strong immunostaining for the three mammalian transforming growth factor beta (TGF-beta) isoforms. These important growth-regulating polypeptides bind to a number of proteins, including the type I TGF-beta receptor (T beta R-I), type II TGF-beta receptor (T beta R-II), and the type III TGF-beta receptor (T beta R-III). In the present study we sought to determine whether T beta R-II and T beta R-III expression is altered in pancreatic cancer. Northern blot analysis indicated that, by comparison with the normal pancreas, pancreatic adenocarcinomas exhibited a 4.6-fold increase (P beta R-II. In contrast, mRNA levels encoding T beta R-III were not increased. In situ hybridization showed that T beta R-II mRNA was expressed in the majority of cancer cells, whereas mRNA grains encoding T beta R-III were detectable in only a few cancer cells and were present mainly in the surrounding stroma. These findings suggest that enhanced levels of T beta R-II may have a role in regulating human pancreatic cancer cell growth, while T beta R-III may function in the extracellular matrix.

  11. An improved method for the isolation of rat alveolar type II lung cells: Use in the Comet assay to determine DNA damage induced by cigarette smoke. (United States)

    Dalrymple, Annette; Ordoñez, Patricia; Thorne, David; Dillon, Debbie; Meredith, Clive


    Smoking is a cause of serious diseases, including lung cancer, emphysema, chronic bronchitis and heart disease. DNA damage is thought to be one of the mechanisms by which cigarette smoke (CS) initiates disease in the lung. Indeed, CS induced DNA damage can be measured in vitro and in vivo. The potential of the Comet assay to measure DNA damage in isolated rat lung alveolar type II epithelial cells (AEC II) was explored as a means to include a genotoxicity end-point in rodent sub-chronic inhalation studies. In this study, published AEC II isolation methods were improved to yield viable cells suitable for use in the Comet assay. The improved method reduced the level of basal DNA damage and DNA repair in isolated AEC II. CS induced DNA damage could also be quantified in isolated cells following a single or 5 days CS exposure. In conclusion, the Comet assay has the potential to determine CS or other aerosol induced DNA damage in AEC II isolated from rodents used in sub-chronic inhalation studies.

  12. Transcriptomic profiles of peripheral white blood cells in type II diabetes and racial differences in expression profiles

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    Mao Jinghe


    Full Text Available Abstract Background Along with obesity, physical inactivity, and family history of metabolic disorders, African American ethnicity is a risk factor for type 2 diabetes (T2D in the United States. However, little is known about the differences in gene expression and transcriptomic profiles of blood in T2D between African Americans (AA and Caucasians (CAU, and microarray analysis of peripheral white blood cells (WBCs from these two ethnic groups will facilitate our understanding of the underlying molecular mechanism in T2D and identify genetic biomarkers responsible for the disparities. Results A whole human genome oligomicroarray of peripheral WBCs was performed on 144 samples obtained from 84 patients with T2D (44 AA and 40 CAU and 60 healthy controls (28 AA and 32 CAU. The results showed that 30 genes had significant difference in expression between patients and controls (a fold change of 1.4 with a P value Conclusions These newly identified genetic markers in WBCs provide valuable information about the pathophysiology of T2D and can be used for diagnosis and pharmaceutical drug design. Our results also found that AA and CAU patients with T2D express genes and pathways differently.

  13. High rate of infection with the human T-cell leukemia retrovirus type II in four Indian populations of Argentina. (United States)

    Ferrer, J F; Del Pino, N; Esteban, E; Sherman, M P; Dube, S; Dube, D K; Basombrio, M A; Pimentel, E; Segovia, A; Quirulas, S


    Sera from 215 non-drug-injecting Toba and Mataco-Mataguayo pure Indians belonging to four communities in northern Argentina were examined using assays that allow differentiation between reactivities due to type-specific antigens of the human T-cell leukemia/lymphoma virus (HTLV). Three of these populations have very little contact with non-Indian groups and reside in remote, isolated areas. HTLV-II type-specific seroreactivity was present in 24 (13.7%) of the 175 Indians older than 13 years of age and in none of the 40 who were of younger ages. None of the Indians had antibodies reacting with HTLV-I type-specific antigen. Seroreactivity was more prevalent and appeared at younger ages in females than in males. The majority of the HTLV-II-seropositive Indians belonged to the more isolated communities. The seroprevalences among the Tobas and Mataco-Mataguayo Indians were comparable. With the exception of a Toba who was positive in a test for Treponema pallidum, no serological evidence of sexually transmitted infections with this spirochete, hepatitis B virus, hepatitis C virus, and human immunodeficiency virus was found among the Indians tested. None of the 55 non-Indian people tested in the region showed HTLV-II type-specific seroreactivity. PCR analysis of DNA isolated from peripheral blood lymphocytes of seropositive Indians confirmed that the virus present in these populations is HTLV-II. Sequence analysis of PCR-amplified genomic segments showed that the virus belongs to the HTLV-II subtype which has been found to be endemic in other Paleo-American Indians.

  14. Type II VLDLR promotes cell migration by up-regulation of VEGF, MMP2 and MMP7 in breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    Lei He; Yanjun Lu; Jianli Guo


    Objective:Very low density lipoprotein receptor (VLDLR) has been considered as a multiple function receptor due to binding numerous ligands, causing endocytosis and regulating cel ular signaling. Our group previously reported that type II VLDLR overexpression in breast cancer tissues. The purpose of this study is to characterize type II VLDLR activities during cel migration using breast cancer cel lines. Methods:Western blotting was used to test protein expression. Cel migration was analyzed by Scratch wound assay. The mRNA expression was tested by realtime-PCR. Reporter assay was to test the transcription activity. Results:Scratch wound and Report assay indicated up-regulated VLDLR II expression promotes cel migration via activating Wnt/β-catenin pathway. The target genes such as VEGF, MMP2 and MMP7 were upregulated in VLDLR II overexpressed cel s. On the contrary, cel s treated with TFPI had an inhibition ef ect of cel migration response to down-regulation of VLDLR II. Conclusion:Type II VLDLR conferred a migration and invasion advantage by activating Wnt/β-catenin pathway, then up-regulating VEGF, MMP2 and MMP7 in breast cancer cel s.

  15. Involvement of P2X7 receptor signaling on regulating the differentiation of Th17 cells and type II collagen-induced arthritis in mice (United States)

    Fan, Zhi-Dan; Zhang, Ya-Yuan; Guo, Yi-Hong; Huang, Na; Ma, Hui-Hui; Huang, Hui; Yu, Hai-Guo


    Interleukin (IL)-17 producing T helper (Th17) cells are major effector cells in the pathogenesis of rheumatoid arthritis (RA). The P2X7 receptor (P2X7R) has emerged as a potential site in the regulation of inflammation in RA but little is known of its functional role on the differentiation of Th17 cells. This study investigates the in vitro and in vivo effects of P2X7R on Th17 cell differentiation during type II collagen (CII) induced experimental arthritis model. In CII-treated dendritic cells (DCs) and DC/CD4+ T coculture system, pretreatment with pharmacological antagonists of P2X7R (Suramin and A-438079) caused strong inhibition of production of Th17-promoting cytokines (IL-1β, TGF-β1, IL-23p19 and IL-6). Exposure to CII induced the elevation of mRNAs encoding retinoic acid receptor-related orphan receptor α and γt, which were abolished by pretreatment with P2X7R antagonists. Furthermore, blocking P2X7R signaling abolished the CII-mediated increase in IL-17A. Blockade of P2X7R remarkably inhibited hind paw swelling and ameliorated pathological changes in ankle joint of the collagen-induced arthritis mice. Thus, we demonstrated a novel function for P2X7R signaling in regulating CII-induced differentiation of Th17 cells. P2X7R signaling facilitates the development of the sophisticated network of DC-derived cytokines that favors a Th17 phenotype. PMID:27775097

  16. TGF-β receptor type II costameric localization in cardiomyocytes and host cell TGF-β response is disrupted by Trypanosoma cruzi infection. (United States)

    Calvet, Claudia Magalhães; Silva, Tatiana Araújo; DE Melo, Tatiana Galvão; DE Araújo-Jorge, Tânia Cremonini; Pereira, Mirian Claudia DE Souza


    Transforming growth factor beta (TGF-β) cytokine is involved in Chagas disease establishment and progression. Since Trypanosoma cruzi can modulate host cell receptors, we analysed the TGF-β receptor type II (TβRII) expression and distribution during T. cruzi - cardiomyocyte interaction. TβRII immunofluorescent staining revealed a striated organization in cardiomyocytes, which was co-localized with vinculin costameres and enhanced (38%) after TGF-β treatment. Cytochalasin D induced a decrease of 45·3% in the ratio of cardiomyocytes presenting TβRII striations, demonstrating an association of TβRII with the cytoskeleton. Western blot analysis showed that cytochalasin D significantly inhibited Smad 2 phosphorylation and fibronectin stimulation after TGF-β treatment in cardiomyocytes. Trypanosoma cruzi infection elicited a decrease of 79·8% in the frequency of cardiomyocytes presenting TβRII striations, but did not interfere significantly in its expression. In addition, T. cruzi-infected cardiomyocytes present a lower response to exogenous TGF-β, showing no enhancement of TβRII striations and a reduction of phosphorylated Smad 2, with no significant difference in TβRII expression when compared to uninfected cells. Together, these results suggest that the co-localization of TβRII with costameres is important in activating the TGF-β signalling cascade, and that T. cruzi-derived cytoskeleton disorganization could result in altered or low TGF-β response in infected cardiomyocytes.

  17. Endemicity and phylogeny of the human T cell lymphotropic virus type II subtype A from the Kayapo Indians of Brazil: evidence for limited regional dissemination. (United States)

    Switzer, W M; Black, F L; Pieniazek, D; Biggar, R J; Lal, R B; Heneine, W


    Long terminal repeat (LTR)-based restriction fragment length polymorphism (RFLP) analysis of human T cell lymphotropic virus type II (HTLV-II) from 17 seropositive Kayapo Indians from Brazil showed that all 17 samples contained a unique HTLV-IIa subtype (A-II). Additional RFLP screening demonstrated the presence of this subtype in two of three Brazilian blood donors and a Mexican prostitute and her child. In contrast, 129 samples from blood donors and intravenous drug users (IDUs) from the United States, two Pueblo Indian samples, five samples from Norwegian IDUs, and two samples from blood donors from Denmark were all found to be a different HTLV-IIa subtype (A-III). Phylogenetic analysis of two Kayapo and one Mexican LTR sequences showed that they cluster with a subtype A-II sequence from a Brazilian blood donor and with sequences from two prostitutes from Ghana and Cameroon. These results demonstrate that infection with the A-II subtype is endemic among the Kayapo Amerindians, has disseminated to non-Indian populations in Brazil, and is also present in Mexico. Furthermore, the A-II subtype does not appear to represent an origin for the HTLV-IIa infection in urban areas of the United States and Europe. This study provides evidence that HTLV-IIa may be a Paleo-Indian subtype as previously suggested for HTLV-IIb.

  18. Phase 1 study results of the type II glycoengineered humanized anti-CD20 monoclonal antibody obinutuzumab (GA101) in B-cell lymphoma patients. (United States)

    Salles, Gilles; Morschhauser, Franck; Lamy, Thierry; Milpied, Noel; Thieblemont, Catherine; Tilly, Hervé; Bieska, Gabi; Asikanius, Elina; Carlile, David; Birkett, Joe; Pisa, Pavel; Cartron, Guillaume


    Whereas the chimeric type I anti-CD20 Ab rituximab has improved outcomes for patients with B-cell malignancies significantly, many patients with non-Hodgkin lymphoma (NHL) remain incurable. Obinutuzumab (GA101) is a glycoengineered, humanized anti-CD20 type II Ab that has demonstrated superior activity against type I Abs in vitro and in preclinical studies. In the present study, we evaluated the safety, efficacy, and pharmacokinetics of GA101 in a phase 1 study of 21 patients with heavily pretreated, relapsed, or refractory CD20(+) indolent NHL. Patients received GA101 in a dose-escalating fashion (3 per cohort, range 50/100-1200/2000 mg) for 8 × 21-day cycles. The majority of adverse events (AEs) were grades 1 and 2 (114 of 132 total AEs). Seven patients reported a total of 18 grade 3 or 4 AEs. Infusion-related reactions were the most common AE, with most occurring during the first infusion and resolving with appropriate management. Three patients experienced grade 3 or 4 drug-related infusion-related reactions. The best overall response was 43%, with 5 complete responses and 4 partial responses. Data from this study suggest that GA101 was well tolerated and demonstrated encouraging activity in patients with previously treated NHL up to doses of 2000 mg. This trial is registered at as NCT00517530.

  19. Type-II Weyl semimetals. (United States)

    Soluyanov, Alexey A; Gresch, Dominik; Wang, Zhijun; Wu, QuanSheng; Troyer, Matthias; Dai, Xi; Bernevig, B Andrei


    Fermions--elementary particles such as electrons--are classified as Dirac, Majorana or Weyl. Majorana and Weyl fermions had not been observed experimentally until the recent discovery of condensed matter systems such as topological superconductors and semimetals, in which they arise as low-energy excitations. Here we propose the existence of a previously overlooked type of Weyl fermion that emerges at the boundary between electron and hole pockets in a new phase of matter. This particle was missed by Weyl because it breaks the stringent Lorentz symmetry in high-energy physics. Lorentz invariance, however, is not present in condensed matter physics, and by generalizing the Dirac equation, we find the new type of Weyl fermion. In particular, whereas Weyl semimetals--materials hosting Weyl fermions--were previously thought to have standard Weyl points with a point-like Fermi surface (which we refer to as type-I), we discover a type-II Weyl point, which is still a protected crossing, but appears at the contact of electron and hole pockets in type-II Weyl semimetals. We predict that WTe2 is an example of a topological semimetal hosting the new particle as a low-energy excitation around such a type-II Weyl point. The existence of type-II Weyl points in WTe2 means that many of its physical properties are very different to those of standard Weyl semimetals with point-like Fermi surfaces.

  20. Gentamicin Blocks the ACh-Induced BK Current in Guinea Pig Type II Vestibular Hair Cells by Competing with Ca2+ at the l-Type Calcium Channel

    Directory of Open Access Journals (Sweden)

    Hong Yu


    Full Text Available Type II vestibular hair cells (VHCs II contain big-conductance Ca2+-dependent K+ channels (BK and L-type calcium channels. Our previous studies in guinea pig VHCs II indicated that acetylcholine (ACh evoked the BK current by triggering the influx of Ca2+ ions through l-type Ca2+ channels, which was mediated by M2 muscarinic ACh receptor (mAChRs. Aminoglycoside antibiotics, such as gentamicin (GM, are known to have vestibulotoxicity, including damaging effects on the efferent nerve endings on VHCs II. This study used the whole-cell patch clamp technique to determine whether GM affects the vestibular efferent system at postsynaptic M2-mAChRs or the membrane ion channels. We found that GM could block the ACh-induced BK current and that inhibition was reversible, voltage-independent, and dose-dependent with an IC50 value of 36.3 ± 7.8 µM. Increasing the ACh concentration had little influence on GM blocking effect, but increasing the extracellular Ca2+ concentration ([Ca2+]o could antagonize it. Moreover, 50 µM GM potently blocked Ca2+ currents activated by (--Bay-K8644, but did not block BK currents induced by NS1619. These observations indicate that GM most likely blocks the M2 mAChR-mediated response by competing with Ca2+ at the l-type calcium channel. These results provide insights into the vestibulotoxicity of aminoglycoside antibiotics on mammalian VHCs II.

  1. Microanalysis of Plant Cell Wall Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    Nicolai Obel; Veronika Erben; Tatjana Schwarz; Stefan Kühne; Andrea Fodor; Markus Pauly


    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 study of a wide range of plant organs, revealing a high degree of heterogeneity in the substitution pattern of wall polymers such as the cross-linking glycan xyloglucan and the pectic polysaccharide homogalacturonan. The high sensitivity of MALDI-TOF allows the use of small amounts of samples, thus making it possible to investigate the wall structure of single cell types when material is collected by such methods as laser micro-dissection. As an example, the analysis of the xyloglucan structure in the leaf cell types outer epidermis layer, entire epidermis cell layer, palisade mesophyll cells, and vascular bundles were investigated. OLIMP is amenable to in situ wall analysis, where wall polymers are analyzed on unprepared plant tissue itself without first iso-lating cell walls. In addition, OLIMP enables analysis of wall polymers in Golgi-enriched fractions, the location of nascent matrix polysaccharide biosynthesis, enabling separation of the processes of wall biosynthesis versus post-deposition apo-plastic metabolism. These new tools will make possible a semi-quantitative analysis of the cell wall at an unprecedented level.

  2. [The cell wall of Coelastrum (Chlorophycees)]. (United States)

    Reymond, O


    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.

  3. BMP type II receptor deficiency confers resistance to growth inhibition by TGF-β in pulmonary artery smooth muscle cells: role of proinflammatory cytokines. (United States)

    Davies, Rachel J; Holmes, Alan M; Deighton, John; Long, Lu; Yang, Xudong; Barker, Lucy; Walker, Christoph; Budd, David C; Upton, Paul D; Morrell, Nicholas W


    Mutations in the bone morphogenetic protein (BMP) type II receptor (BMPR-II) underlie most cases of heritable pulmonary arterial hypertension (HPAH) and a significant proportion of sporadic cases. Pulmonary artery smooth muscle cells (PASMCs) from patients with pulmonary arterial hypertension (PAH) not only exhibit attenuated growth suppression by BMPs, but an abnormal mitogenic response to transforming growth factor (TGF)-β1. We sought to define the mechanism underlying this loss of the antiproliferative effects of TGF-β1 in BMPR-II-deficient PASMCs. The effect of TGF-β1 on PASMC proliferation was characterized in three different models of BMPR-II dysfunction: 1) HPAH PASMCs, 2) Bmpr2(+/-) mouse PASMCs, and 3) control human PASMCs transfected with BMPR-II small interfering RNA. BMPR-II reduction consistently conferred insensitivity to growth inhibition by TGF-β1. This was not associated with altered canonical TGF-β1/Smad signaling but was associated with a secreted factor. Microarray analysis revealed that the transcriptional responses to TGF-β1 differed between control and HPAH PASMCs, particularly regarding genes associated with interleukins and inflammation. HPAH PASMCs exhibited enhanced IL-6 and IL-8 induction by TGF-β1, an effect reversed by NF-κB inhibition. Moreover, neutralizing antibodies to IL-6 or IL-8 restored the antiproliferative effect of TGF-β1 in HPAH PASMCs. This study establishes that BMPR-II deficiency leads to failed growth suppression by TGF-β1 in PASMCs. This effect is Smad-independent but is associated with inappropriately altered NF-κB signaling and enhanced induction of IL-6 and IL-8 expression. Our study provides a rationale to test anti-interleukin therapies as an intervention to neutralize this inappropriate response and restore the antiproliferative response to TGF-β1.

  4. Alterations of alveolar type II cells and intraalveolar surfactant after bronchoalveolar lavage and perfluorocarbon ventilation. An electron microscopical and stereological study in the rat lung

    Directory of Open Access Journals (Sweden)

    Burkhardt Wolfram


    Full Text Available Abstract Background Repeated bronchoalveolar lavage (BAL has been used in animals to induce surfactant depletion and to study therapeutical interventions of subsequent respiratory insufficiency. Intratracheal administration of surface active agents such as perfluorocarbons (PFC can prevent the alveolar collapse in surfactant depleted lungs. However, it is not known how BAL or subsequent PFC administration affect the intracellular and intraalveolar surfactant pool. Methods Male wistar rats were surfactant depleted by BAL and treated for 1 hour by conventional mechanical ventilation (Lavaged-Gas, n = 5 or partial liquid ventilation with PF 5080 (Lavaged-PF5080, n = 5. For control, 10 healthy animals with gas (Healthy-Gas, n = 5 or PF5080 filled lungs (Healthy-PF5080, n = 5 were studied. A design-based stereological approach was used for quantification of lung parenchyma and the intracellular and intraalveolar surfactant pool at the light and electron microscopic level. Results Compared to Healthy-lungs, Lavaged-animals had more type II cells with lamellar bodies in the process of secretion and freshly secreted lamellar body-like surfactant forms in the alveoli. The fraction of alveolar epithelial surface area covered with surfactant and total intraalveolar surfactant content were significantly smaller in Lavaged-animals. Compared with Gas-filled lungs, both PF5080-groups had a significantly higher total lung volume, but no other differences. Conclusion After BAL-induced alveolar surfactant depletion the amount of intracellularly stored surfactant is about half as high as in healthy animals. In lavaged animals short time liquid ventilation with PF5080 did not alter intra- or extracellular surfactant content or subtype composition.

  5. Phosphatidylinositol 5-phosphate 4-kinase type II beta is required for vitamin D receptor-dependent E-cadherin expression in SW480 cells

    Energy Technology Data Exchange (ETDEWEB)

    Kouchi, Zen, E-mail: [Laboratory of Genome and Biosignals, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-city, Tokyo 192-0392 (Japan); Fujiwara, Yuki [Laboratory of Genome and Biosignals, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-city, Tokyo 192-0392 (Japan); Yamaguchi, Hideki [Division of Metastasis and Invasion Signaling, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi-city, Saitama 332-0012 (Japan); Nakamura, Yoshikazu; Fukami, Kiyoko [Laboratory of Genome and Biosignals, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji-city, Tokyo 192-0392 (Japan)


    Highlights: {yields} We analyzed Phosphatidylinositol 5-phosphate kinase II{beta} (PIPKII{beta}) function in cancer. {yields} PIPKII{beta} is required for vitamin D receptor-mediated E-cadherin upregulation in SW480. {yields} PIPKII{beta} suppresses cellular motility through E-cadherin induction in SW480 cells. {yields} Nuclear PIP{sub 2} but not plasma membrane-localized PIP{sub 2} mediates E-cadherin upregulation. -- Abstract: Numerous epidemiological data indicate that vitamin D receptor (VDR) signaling induced by its ligand or active metabolite 1{alpha},25-dihydroxyvitamin D{sub 3} (1{alpha},25(OH){sub 2}D{sub 3}) has anti-cancer activity in several colon cancers. 1{alpha},25(OH){sub 2}D{sub 3} induces the epithelial differentiation of SW480 colon cancer cells expressing VDR (SW480-ADH) by upregulating E-cadherin expression; however, its precise mechanism remains unknown. We found that phosphatidylinositol-5-phosphate 4-kinase type II beta (PIPKII{beta}) but not PIPKII{alpha} is required for VDR-mediated E-cadherin induction in SW480-ADH cells. The syntenin-2 postsynaptic density protein/disc large/zona occludens (PDZ) domain and pleckstrin homology domain of phospholipase C-delta1 (PLC{delta}1 PHD) possess high affinity for phosphatidylinositol-4,5-bisphosphate (PI(4,5)P{sub 2}) mainly localized to the nucleus and plasma membrane, respectively. The expression of syntenin-2 PDZ but not PLC{delta}1 PHD inhibited 1{alpha},25(OH){sub 2}D{sub 3}-induced E-cadherin upregulation, suggesting that nuclear PI(4,5)P{sub 2} production mediates E-cadherin expression through PIPKII{beta} in a VDR-dependent manner. PIPKII{beta} is also involved in the suppression of the cell motility induced by 1{alpha},25(OH){sub 2}D{sub 3}. These results indicate that PIPKII{beta}-mediated PI(4,5)P{sub 2} signaling is important for E-cadherin upregulation and inhibition of cellular motility induced by VDR activation.

  6. Isolation of plant cell wall proteins


    Jamet, Elisabeth; Boudart, Georges; Borderies, Gisèle; Charmont, Stéphane; Lafitte, Claude; Rossignol, Michel; Canut, Hervé; Pont-Lezica, Rafael F


    The quality of a proteomic analysis of a cell compartment strongly depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific drawbacks: (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; (iii) the presence of proteins ...

  7. Isolation of plant cell wall proteins. (United States)

    Jamet, Elisabeth; Boudart, Georges; Borderies, Giséle; Charmont, Stephane; Lafitte, Claude; Rossignol, Michel; Canut, Herve; Pont-Lezica, Rafael


    The quality of a proteomic analysis of a cell compartment strongly depends on the reliability of the isolation procedure for the cell compartment of interest. Plant cell walls possess specific drawbacks: (1) the lack of a surrounding membrane may result in the loss of cell wall proteins (CWP) during the isolation procedure; (2) polysaccharide networks of cellulose, hemicelluloses, and pectins form potential traps for contaminants such as intracellular proteins; (3) the presence of proteins interacting in many different ways with the polysaccharide matrix require different procedures to elute them from the cell wall. Three categories of CWP are distinguished: labile proteins that have little or no interactions with cell wall components, weakly bound proteins extractable with salts, and strongly bound proteins. Two alternative protocols are decribed for cell wall proteomics: (1) nondestructive techniques allowing the extraction of labile or weakly bound CWP without damaging the plasma membrane; (2) destructive techniques to isolate cell walls from which weakly or strongly bound CWP can be extracted. These protocols give very low levels of contamination by intracellular proteins. Their application should lead to a realistic view of the cell wall proteome at least for labile and weakly bound CWP extractable by salts.

  8. [Tyrosinemia type II. Case report]. (United States)

    Benatiya, A I; Bouayed, M A; Touiza, E; Daoudi, K; Bhalil, S; Elmesbahi, I; Tahri, H


    Tyrosinemia type II or Richner-Hanhart syndrome is a rare hereditary disease characterized by the association of pseudoherpetiform corneal ulcerations and palmoplantar hyperkeratosis. We report the case of a 12 year-old young man presenting a superficial punctate keratitis and a corneal dystrophy in both eyes, associated with a palmoplantar hyperkeratosis. The dosage of the serum level of tyrosine is meaningfully raised to 1236 micromol/l. A dietary treatment restraining tyrosine and phenylalanine is started with favorable results after an evolution of 6 months. Tyrosinemia type II is an autosomal recessive disease, due to an enzymatic deficit in tyrosine aminotransferase. The diagnosis is based on the clinic and high level of serum and urinary tyrosine as well as of its urinary metabolites. This disease must be suspected in all cases of dentritic keratitis not reacting on the antiviral treatment, and more especially if it is associated with cutaneous lesions such as palmo-plantar keratosis.

  9. The effect of interleukin-13 (IL-13 and interferon-γ (IFN-γ on expression of surfactant proteins in adult human alveolar type II cells in vitro

    Directory of Open Access Journals (Sweden)

    Mason Robert J


    Full Text Available Abstract Background Surfactant proteins are produced predominantly by alveolar type II (ATII cells, and the expression of these proteins can be altered by cytokines and growth factors. Th1/Th2 cytokine imbalance is suggested to be important in the pathogenesis of several adult lung diseases. Recently, we developed a culture system for maintaining differentiated adult human ATII cells. Therefore, we sought to determine the effects of IL-13 and IFN-γ on the expression of surfactant proteins in adult human ATII cells in vitro. Additional studies were done with rat ATII cells. Methods Adult human ATII cells were isolated from deidentified organ donors whose lungs were not suitable for transplantation and donated for medical research. The cells were cultured on a mixture of Matrigel and rat-tail collagen for 8 d with differentiation factors and human recombinant IL-13 or IFN-γ. Results IL-13 reduced the mRNA and protein levels of surfactant protein (SP-C, whereas IFN-γ increased the mRNA level of SP-C and proSP-C protein but not mature SP-C. Neither cytokine changed the mRNA level of SP-B but IFN-γ slightly decreased mature SP-B. IFN-γ reduced the level of the active form of cathepsin H. IL-13 also reduced the mRNA and protein levels of SP-D, whereas IFN-γ increased both mRNA and protein levels of SP-D. IL-13 did not alter SP-A, but IFN-γ slightly increased the mRNA levels of SP-A. Conclusions We demonstrated that IL-13 and IFN-γ altered the expression of surfactant proteins in human adult ATII cells in vitro. IL-13 decreased SP-C and SP-D in human ATII cells, whereas IFN-γ had the opposite effect. The protein levels of mature SP-B were decreased by IFN-γ treatment, likely due to the reduction in active form cathpesin H. Similarly, the active form of cathepsin H was relatively insufficient to fully process proSP-C as IFN-γ increased the mRNA levels for SP-C and proSP-C protein, but there was no increase in mature SP-C. These observations

  10. Accelerating forward genetics for cell wall deconstruction

    Directory of Open Access Journals (Sweden)

    Danielle eVidaurre


    Full Text Available One of the biggest challenges of cell wall biology is the elucidation of the genes involved the cell wall and their function due to the recalcitrance of the cell wall. Through traditional genetic approaches, many simple yet elegant screens have been able to identify components of the cell wall and their networks. Despite progress in the identification of several genes of the cell wall, there remain many unknown players whose function has yet to be determined. Exhausting the genetic toolbox by performing secondary screens on a genetically mutated background, chemical genetics using small molecules and improved cell wall imaging hold promise for new gene discovery and function. With the recent introduction of next-generation sequencing technologies, it is now possible to quickly and efficiently map and clone genes of interest in Arabidopsis and any model organism with a completed genome sequence. The combination of a classical genetics approach and cutting edge technology will propel cell wall biology of Arabidopsis and other useful crops forward into the future.

  11. Recent advances in plant cell wall proteomics. (United States)

    Jamet, Elisabeth; Albenne, Cécile; Boudart, Georges; Irshad, Muhammad; Canut, Hervé; Pont-Lezica, Rafael


    The plant extracellular matrix contains typical polysaccharides such as cellulose, hemicelluloses, and pectins that interact to form dense interwoven networks. Plant cell walls play crucial roles during development and constitute the first barrier of defense against invading pathogens. Cell wall proteomics has greatly contributed to the description of the protein content of a compartment specific to plants. Around 400 cell wall proteins (CWPs) of Arabidopsis, representing about one fourth of its estimated cell wall proteome, have been described. The main points to note are that: (i) the diversity of enzymes acting on polysaccharides suggests a great plasticity of cell walls; (ii) CWPs such as proteases, polysaccharide hydrolytic enzymes, and lipases may contribute to the generation of signals; (iii) proteins of unknown functions were identified, suggesting new roles for cell walls. Recently, the characterization of PTMs such as N- and O-glycosylations improved our knowledge of CWP structure. The presence of many glycoside hydrolases and proteases suggests a complex regulation of CWPs involving various types of post-translational events. The first 3-D structures to be resolved gave clues about the interactions between CWPs, or between CWPs and polysaccharides. Future work should include: extracting and identifying CWPs still recalcitrant to proteomics, describing the cell wall interactome, improving quantification, and unraveling the roles of each of the CWPs.

  12. Molecular regulation of plant cell wall extensibility (United States)

    Cosgrove, D. J.


    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.

  13. 2003 Plant Cell Walls Gordon Conference

    Energy Technology Data Exchange (ETDEWEB)

    Daniel J. Cosgrove


    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.

  14. Function of laccases in cell wall biosynthesis

    DEFF Research Database (Denmark)

    Larsen, Anders; Holm, Preben Bach; Andersen, Jeppe Reitan


    substrate specificities and expression patterns. As part of the strategic research centre Bio4Bio, the present project deals with laccase functions in relation to cell wall formation in grasses based on a study of the model species Brachypodium distachyon. Thirty-one isozymes have been retrieved from......Laccases are multicopper oxidases capable of polymerizing monolignols. Histochemical assays have shown temporal and spatial correlation with secondary cell wall formation in both herbs and woody perennials. However, in plants laccases constitutes a relatively large group of isoenzymes with unique...... hybridization. Specific isozymes that show high correlation with the process of secondary cell wall formation will be further studied in a reverse genetic study in which candidates will be knocked out using RNA interference. Phenotypes of knock-out mutants are to be described in relation to cell wall...

  15. Cell wall proteins: a new insight through proteomics. (United States)

    Jamet, Elisabeth; Canut, Hervé; Boudart, Georges; Pont-Lezica, Rafael F


    Cell wall proteins are essential constituents of plant cell walls; they are involved in modifications of cell wall components, wall structure, signaling and interactions with plasma membrane proteins at the cell surface. The application of proteomic approaches to the cell wall compartment raises important questions: are there technical problems specific to cell wall proteomics? What kinds of proteins can be found in Arabidopsis walls? Are some of them unexpected? What sort of post-translational modifications have been characterized in cell wall proteins to date? The purpose of this review is to discuss the experimental results obtained to date using proteomics, as well as some of the new questions challenging future research.

  16. Modes of deformation of walled cells. (United States)

    Dumais, Jacques


    The bewildering morphological diversity found in cells is one of the starkest illustrations of life's ability to self-organize. Yet the morphogenetic mechanisms that produce the multifarious shapes of cells are still poorly understood. The shared similarities between the walled cells of prokaryotes, many protists, fungi, and plants make these groups particularly appealing to begin investigating how morphological diversity is generated at the cell level. In this review, I attempt a first classification of the different modes of surface deformation used by walled cells. Five modes of deformation were identified: inextensional bending, equi-area shear, elastic stretching, processive intussusception, and chemorheological growth. The two most restrictive modes-inextensional and equi-area deformations-are embodied in the exine of pollen grains and the wall-like pellicle of euglenoids, respectively. For these modes, it is possible to express the deformed geometry of the cell explicitly in terms of the undeformed geometry and other easily observable geometrical parameters. The greatest morphogenetic power is reached with the processive intussusception and chemorheological growth mechanisms that underlie the expansive growth of walled cells. A comparison of these two growth mechanisms suggests a possible way to tackle the complexity behind wall growth.

  17. Identification of Novel Cell Wall Components

    Energy Technology Data Exchange (ETDEWEB)

    Michelle Momany


    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.

  18. "Steiner trees" between cell walls of sisal

    Institute of Scientific and Technical Information of China (English)

    LI GuanShi; YIN YaJun; LI Yan; ZHONG Zheng


    Through careful analysis on the cross-section of sisal fibers,it is found that the middle lamellae between the cell walls have clear geometric characteristics:between the cell walls of three neighboring cells,the middle lamellae form a three-way junction with 120°symmetry. If the neighboring three-way junctions are connected,a network of Steiner tree with angular symmetry and topological invariability is formed. If more and more Steiner trees are connected,a network of Steiner rings is generated. In another word,idealized cell walls and the middle lamellae are dominated by the Steiner geometry. This geometry not only depicts the geometric symmetry,the topological invariability and minimal property of the middle lamellae,but also controls the mechanics of sisal fibers.

  19. Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor

    DEFF Research Database (Denmark)

    Nørgaard, P; Damstrup, L; Rygaard, K;


    was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating...... the growth-suppressive effect of TGF-beta 1, the expression of functional pRb, as characterised by nuclear localisation, was examined by immunocytochemistry. Nuclear association of pRb was only seen in two of the five TGF-beta 1-responsive cell lines. These results indicate that in SCLC pRb is not required...

  20. Cell wall oxalate oxidase modifies the ferulate metabolism in cell walls of wheat shoots. (United States)

    Wakabayashi, Kazuyuki; Soga, Kouichi; Hoson, Takayuki


    Oxalate oxidase (OXO) utilizes oxalate to generate hydrogen peroxide, and thereby acts as a source of hydrogen peroxide. The present study was carried out to investigate whether apoplastic OXO modifies the metabolism of cell wall-bound ferulates in wheat seedlings. Histochemical staining of OXO showed that cell walls were strongly stained, indicating the presence of OXO activity in shoot walls. When native cell walls prepared from shoots were incubated with oxalate or hydrogen peroxide, the levels of ester-linked diferulic acid (DFA) isomers were significantly increased. On the other hand, the level of ester-linked ferulic acid (FA) was substantially decreased. The decrease in FA level was accounted neither by the increases in DFA levels nor by the release of FA from cell walls during the incubation. After the extraction of ester-linked ferulates, considerable ultraviolet absorption remained in the hemicellulosic and cellulose fractions, which was increased by the treatment with oxalate or hydrogen peroxide. Therefore, a part of FA esters may form tight linkages within cell wall architecture. These results suggest that cell wall OXO is capable of modifying the metabolism of ester-linked ferulates in cell walls of wheat shoots by promoting the peroxidase action via supply of hydrogen peroxide.

  1. Enzymatic Modification of Plant Cell Wall Polysaccharides

    DEFF Research Database (Denmark)

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


    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......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...... 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...

  2. Xyloglucan endotransglucosylase and cell wall extensibility. (United States)

    Miedes, E; Zarra, I; Hoson, T; Herbers, K; Sonnewald, U; Lorences, E P


    Transgenic tomato hypocotyls with altered levels of an XTH gene were used to study how XET activity could affect the hypocotyl growth and cell wall extensibility. Transgenic hypocotyls showed significant over-expression (line 13) or co-suppression (line 33) of the SlXTH1 in comparison with the wild type, with these results being correlated with the results on specific soluble XET activity, suggesting that SlXTH1 translates mainly for a soluble XET isoenzyme. A relationship between XET activity and cell wall extensibility was found, and the highest total extensibility was located in the apical hypocotyl segment of the over-expressing SlXTH1 line, where the XET-specific activity and hypocotyl growth were also highest compared with the wild line. Also, in the co-suppression SlXTH1 line, total extensibility values were lower than in the wild type line. The study of linkages between cell wall polysaccharides by FTIR showed that hypocotyls over-expressing SlXTH1 and having a higher XET-specific activity, were grouped away from the wild line, indicating that the linkages between pectins and between cellulose and xyloglucans might differ. These results suggested that the action of the increased XET activity in the transgenic line could be responsible for the cell wall structural changes, and therefore, alter the cell wall extensibility. On the other hand, results on xyloglucan oligosaccharides composition of the xyloglucan by MALDI TOF-MS showed no differences between lines, indicating that the xyloglucan structure was not affected by the XET action. These results provide evidences that XTHs from group I are involved mainly in the restructuring of the cell wall during growth and development, but they are not the limiting factor for plant growth.

  3. Radiosurgery for type II neurofibromatosis. (United States)

    Rowe, Jeremy; Radatz, Matthias; Kemeny, Andras


    A summary of our radiosurgical experience treating type II neurofibromatosis (NF2) vestibular schwannomas (VSs), based on a retrospective consecutive series of 122 tumours in 92 patients, with an extended series of a further 22 patients (906 patient-years of follow-up) to investigate the risk of malignancy after radiosurgery. With current techniques, we estimate that 8 years after radiosurgery for NF2 VS, 20% of patients will have required further treatment, 50% will be well controlled, and in 30% there will have been some concern about control, but they will have been managed conservatively. Three years after treatment, approximately 40% retain their functional hearing, 40% have some deterioration, 20% becoming deaf in that ear. The risk of facial palsy was 5%. Two malignancies were recorded after radiosurgery, in one the malignant behaviour preceded treatment. This is less than the previously reported rate of spontaneously developing malignant gliomas in NF2. Whilst the clinical results are far worse than those achieved treating sporadic tumours, this applies equally to the results of surgery or observation when treating NF2 tumours. It is important therefore that these patients are given advice specific for NF2. Considering this, we believe that radiosurgery remains a valuable minimally invasive treatment option for selected NF2 patients.

  4. Phagocytic properties of lung alveolar wall cells

    Directory of Open Access Journals (Sweden)



    Full Text Available For the purpose to define the mechanism of heavy metal intoxication by inhalation, morphologic observations were made on rat lungs after nasal instillation of iron colloid particles of positive and negative electric charges. Histochemical observation was also made on the liver and spleen of these animals. The instilled iron colloid particles reach the alveolar cavity easily, as can be seen in the tissue sections stained by Prussian blue reaction. Alveolar macrophages do take up them avidly both of positive and negative charges, though much less the positive particles than negative ones. In contrast, the alveolar epithelial cells take up solely positive particles by phagocytosis but not negative ones. Electron microscope observation revealed that the positive particles are ingested by Type I epithelial cells by pinocytosis and by Type II cells by phagocytosis as well. Then the iron colloid particles are transferred into the basement membrane by exocytosis. Travelling through the basement membrane they are again taken up by capillary endothelial cells by phagocytosis. Some particles were found in the intercellular clefts of capillary endothelial cells but not any iron colloid particles in the intercellular spaces of epithelial cells and in the capillary lumen. However, the liver and spleen tissues of the animals given iron colloid showed a strong positive iron reaction. On the basis of these observations, the mechanism of acute intoxication by inhaling heavy metal dusts like lead fume is discussed from the view point of selective uptake of alveolar epithelial and capillary endothelial cells for the particles of the positive electric cha'rge.

  5. 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.


    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 maiz

  6. Microanalysis of Plant Cell Wall Polysaccharides

    NARCIS (Netherlands)

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


    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 s

  7. Cell Wall Heterogeneity in Root Development of Arabidopsis (United States)

    Somssich, Marc; Khan, Ghazanfar Abbas; Persson, Staffan


    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 signaling 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-modeling to developmental stages of root cells, and dissect how root cell walls respond to certain environmental changes. PMID:27582757

  8. Arrangement of peptidoglycan in the cell wall of Staphylococcus spp.


    Amako, K.; Umeda, A; Murata, K


    The arrangement of peptidoglycan in the cell wall of Staphylococcus was observed with the newly developed freeze-fracture technique, using n-octanol instead of water as the freezing medium. The replica of the trichloroacetic acid-extracted cell wall (TCA-wall) showed two areas. One of them has a concentric circular structure, a characteristic surface structure of the staphylococcal cell wall, and the other showed an irregular and rough surface. The chemical analysis of the wall revealed that ...

  9. Interconnections between cell wall polymers, wall mechanics, and cortical microtubules: Teasing out causes and consequences. (United States)

    Xiao, Chaowen; Anderson, Charles T


    In plants, cell wall components including cellulose, hemicelluloses, and pectins interact with each other to form complex extracellular network structures that control cell growth and maintain cell shape. However, it is still not clear exactly how different wall polymers interact, how the conformations and interactions of cell wall polymers relate to wall mechanics, and how these factors impinge on intracellular structures such as the cortical microtubule cytoskeleton. Here, based on studies of Arabidopsis thaliana xxt1 xxt2 mutants, which lack detectable xyloglucan in their walls and display aberrant wall mechanics, altered cellulose patterning and biosynthesis, and reduced cortical microtubule stability, we discuss the potential relationships between cell wall biosynthesis, wall mechanics, and cytoskeletal dynamics in an effort to better understand their roles in controlling plant growth and morphogenesis.

  10. Reversal of tolerance induced by transplantation of skin expressing the immunodominant T cell epitope of rat type II collagen entitles development of collagen-induced arthritis but not graft rejection

    DEFF Research Database (Denmark)

    Bäcklund, Johan; Treschow, Alexandra; Firan, Mihail


    collagen (CI), e.g. in skin, are tolerized against rat CII and resistant to CIA. In this study we transplanted skin from TSC transgenic mice onto non-transgenic CIA-susceptible littermates to investigate whether introduction of this epitope to a naïve immune system would lead to T cell priming and graft......Collagen-induced arthritis (CIA) is induced in H-2(q) mice after immunization with rat type II collagen (CII). The immunodominant T cell epitope on heterologous CII has been located to CII256-270. We have previously shown that TSC transgenic mice, which express the heterologous epitope in type I...... rejection or instead to tolerance and arthritis protection. Interestingly, TSC grafts were accepted and not even immunization of recipient mice with CII in adjuvant induced graft rejection. Instead, TSC skin recipients displayed a reduced T and B cell response to CII and were also protected from arthritis...

  11. Plant Cell Wall Matrix Polysaccharide Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Ajay Pal S. Sandhu; Gursharn S. Randhawa; Kanwarpal S. Dhugga


    The wall of an expanding plant cell consists primarily of cellulose microfibrils embedded in a matrix of hemi-cellulosic and pectic polysaccharides along with small amounts of structural and enzymatic proteins. Matrix polysacchar-ides are synthesized in the Golgi and exported to the cell wall by exocytosis, where they intercalate among cellulose microfibrUs, which are made at the plasma membrane and directly deposited into the cell wall. Involvement of Golgi glucan synthesis in auxin-induced cell expansion has long been recognized; however, only recently have the genes corresponding to glucan synthases been identified. Biochemical purification was unsuccessful because of the labile nature and very low abundance of these enzymes. Mutational genetics also proved fruitless. Expression of candidate genes identified through gene expression profiling or comparative genomics in heterologous systems followed by functional characterization has been relatively successful. Several genes from the cellulose synthase-like (Cs/) family have been found to be involved in the synthesis of various hemicellulosic glycans. The usefulness of this approach, however, is limited to those enzymes that probably do not form complexes consisting of unrelated proteins. Nonconventional approaches will continue to incre-mentally unravel the mechanisms of Golgi polysaccharide biosynthesis.

  12. Clinical and morphological features of Waardenburg syndrome type II. (United States)

    Mullaney, P B; Parsons, M A; Weatherhead, R G; Karcioglu, Z A


    Evaluation of 4-month-old girl who presented with congenital cataracts revealed heterochromia iridis, fundus hypopigmentation, residual white forelock and sensory neural hearing loss--findings consistent with Waardenburg syndrome type II. Bilateral peripheral iridectomies performed at lensectomy provided tissue for evaluation. Light microscopy revealed fewer melanocytes in the blue iris than in the brown. Electron microscopic examination showed a significant (p = 0.0001) reduction in melanosome size in the blue iris, and the nerve endings contained fewer vesicles. A defect in neural crest cell migration and melanin synthesis may be responsible for the heterochromia iridis seen in Waardenburg syndrome type II.

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

    NARCIS (Netherlands)

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


    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 proliferatio

  14. [Structure and function of fungal cell wall]. (United States)

    Ohno, Naohito


    Cell wall glycans of fungi/yeasts are reviewed. Fungi/yeasts produce various kinds of polysaccharides. As part of the cell wall they are interlinked with other components forming a huge network. The insolubility and complex with multiple components makes the research very tough. Studies on beta-glucan have been performed from various views, such as chemistry, conformation, solubility, tissue distribution and metabolism, biological activity, clinical application, receptor, biosynthesis, and antibody. Studies on mannan focus on immunotoxicity, such as anaphylactoid reaction and coronary arteritis induction. alpha-glucan, chitin, and capsular polysaccharide were also mentioned in relation to structure and genes. Compared with human and animal polysaccharides, fungi/yeasts polysaccharides have very characteristic properties.

  15. 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)


    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

  16. A note on Type II covolutional codes


    Johannesson, Rolf; Ståhl, Per; Wittenmark, Emma


    The result of a search for the world's second type II (doubly-even and self-dual) convolutional code is reported. A rate R=4/8, 16-state, time-invariant, convolutional code with free distance dfree=8 was found to be type II. The initial part of its weight spectrum is better than that of the Golay convolutional code (GCC). Generator matrices and path weight enumerators for some other type II convolutional codes are given. By the “wrap-around” technique tail-biting versions of (32, 18, 8) T...

  17. 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)


    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

  18. Beyond growth: novel functions for bacterial cell wall hydrolases. (United States)

    Wyckoff, Timna J; Taylor, Jennifer A; Salama, Nina R


    The peptidoglycan cell wall maintains turgor pressure and cell shape of most bacteria. Cell wall hydrolases are essential, together with synthases, for growth and daughter cell separation. Recent work in diverse organisms has uncovered new cell wall hydrolases that act autonomously or on neighboring cells to modulate invasion of prey cells, cell shape, innate immune detection, intercellular communication, and competitor lysis. The hydrolases involved in these processes catalyze the cleavage of bonds throughout the sugar and peptide moities of peptidoglycan. Phenotypes associated with these diverse hydrolases reveal new functions of the bacterial cell wall beyond growth and division.

  19. Plant cell wall proteomics: the leadership of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Cécile eALBENNE


    Full Text Available Plant cell wall proteins (CWPs progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cells walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last ten years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii the main protein families identified and the still missing peptides; (iii the persistent issue of the non-canonical CWPs; (iv the present challenges to overcome technological bottlenecks; and (v the perspectives beyond cell wall proteomics to understand CWP functions.

  20. Plant cell wall proteomics: the leadership of Arabidopsis thaliana. (United States)

    Albenne, Cécile; Canut, Hervé; Jamet, Elisabeth


    Plant cell wall proteins (CWPs) progressively emerged as crucial components of cell walls although present in minor amounts. Cell wall polysaccharides such as pectins, hemicelluloses, and cellulose represent more than 90% of primary cell wall mass, whereas hemicelluloses, cellulose, and lignins are the main components of lignified secondary walls. All these polymers provide mechanical properties to cell walls, participate in cell shape and prevent water loss in aerial organs. However, cell walls need to be modified and customized during plant development and in response to environmental cues, thus contributing to plant adaptation. CWPs play essential roles in all these physiological processes and particularly in the dynamics of cell walls, which requires organization and rearrangements of polysaccharides as well as cell-to-cell communication. In the last 10 years, plant cell wall proteomics has greatly contributed to a wider knowledge of CWPs. This update will deal with (i) a survey of plant cell wall proteomics studies with a focus on Arabidopsis thaliana; (ii) the main protein families identified and the still missing peptides; (iii) the persistent issue of the non-canonical CWPs; (iv) the present challenges to overcome technological bottlenecks; and (v) the perspectives beyond cell wall proteomics to understand CWP functions.

  1. 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.


    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 th

  2. beta-1,3-Glucan-Induced Host Phospholipase D Activation Is Involved in Aspergillus fumigatus Internalization into Type II Human Pneumocyte A549 Cells

    NARCIS (Netherlands)

    Han, Xuelin; Yu, Rentao; Zhen, Dongyu; Tao, Sha; Schmidt, Martina; Han, Li


    The internalization of Aspergillus fumigatus into lung epithelial cells is a process that depends on host cell actin dynamics. The host membrane phosphatidylcholine cleavage driven by phospholipase D (PLD) is closely related to cellular actin dynamics. However, little is known about the impact of PL

  3. Grass Cell Walls: A Story of Cross-Linking (United States)

    Hatfield, Ronald D.; Rancour, David M.; Marita, Jane M.


    Cell wall matrices are complex composites mainly of polysaccharides, phenolics (monomers and polymers), and protein. We are beginning to understand the synthesis of these major wall components individually, but still have a poor understanding of how cell walls are assembled into complex matrices. Valuable insight has been gained by examining intact components to understand the individual elements that make up plant cell walls. Grasses are a prominent group within the plant kingdom, not only for their important roles in global agriculture, but also for the complexity of their cell walls. Ferulate incorporation into grass cell wall matrices (C3 and C4 types) leads to a cross-linked matrix that plays a prominent role in the structure and utilization of grass biomass compared to dicot species. Incorporation of p-coumarates as part of the lignin structure also adds to the complexity of grass cell walls. Feruoylation results in a wall with individual hemicellulosic polysaccharides (arabinoxylans) covalently linked to each other and to lignin. Evidence strongly suggests that ferulates not only cross-link arabinoxylans, but may be important factors in lignification of the cell wall. Therefore, the distribution of ferulates on arabinoxylans could provide a means of structuring regions of the matrix with the incorporation of lignin and have a significant impact upon localized cell wall organization. The role of other phenolics in cell wall formation such as p-coumarates (which can have concentrations higher than ferulates) remains unknown. It is possible that p-coumarates assist in the formation of lignin, especially syringyl rich lignin. The uniqueness of the grass cell wall compared to dicot sepcies may not be so much in the gross composition of the wall, but how the distinctive individual components are organized into a functional wall matrix. These features are discussed and working models are provided to illustrate how changing the organization of feruoylation and p

  4. Enzymes and other agents that enhance cell wall extensibility (United States)

    Cosgrove, D. J.


    Polysaccharides and proteins are secreted to the inner surface of the growing cell wall, where they assemble into a network that is mechanically strong, yet remains extensible until the cells cease growth. This review focuses on the agents that directly or indirectly enhance the extensibility properties of growing walls. The properties of expansins, endoglucanases, and xyloglucan transglycosylases are reviewed and their postulated roles in modulating wall extensibility are evaluated. A summary model for wall extension is presented, in which expansin is a primary agent of wall extension, whereas endoglucanases, xyloglucan endotransglycosylase, and other enzymes that alter wall structure act secondarily to modulate expansin action.

  5. Disruption of cell walls for enhanced lipid recovery (United States)

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


    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.

  6. Aqueous synthesis of type-II CdTe/CdSe core-shell quantum dots for fluorescent probe labeling tumor cells. (United States)

    Zeng, Ruosheng; Zhang, Tingting; Liu, Jincheng; Hu, Song; Wan, Qiang; Liu, Xuanming; Peng, Zhiwei; Zou, Bingsuo


    In this paper, we report a two-step aqueous synthesis of highly luminescent CdTe/CdSe core/shell quantum dots (QDs) via a simple method. The emission range of the CdTe/CdSe QDs can be tuned from 510 to 640 nm by controlling the thickness of the CdSe shell. Accordingly, the photoluminescence quantum yield (PL QY) of CdTe/CdSe QDs with an optimized thickness of the CdSe shell can reach up to 40%. The structures and compositions of the core/shell QDs were characterized by transmission electron microscopy, x-ray diffraction, and x-ray photoelectron spectroscopy experiments, and their formation mechanism is discussed. Furthermore, folate conjugated CdTe/CdSe QDs in Hela cells were assessed with a fluorescence microscope. The results show that folate conjugated CdTe/CdSe QDs could enter tumor cells efficiently.

  7. A Combination of Human Embryonic Stem Cell-Derived Pancreatic Endoderm Transplant with LDHA-Repressing miRNA Can Attenuate High-Fat Diet Induced Type II Diabetes in Mice

    Directory of Open Access Journals (Sweden)

    Yunya Chen


    Full Text Available Type II diabetes mellitus (T2D is a chronic metabolic disorder that results from defects in both insulin secretion and insulin action. The deficit and dysfunction of insulin secreting β-cell are signature symptom for T2D. Additionally, in pancreatic β-cell, a small group of genes which are abundantly expressed in most other tissues are highly selectively repressed. Lactate dehydrogenase A (LDHA is one of such genes. Upregulation of LDHA is found in both human T2D and rodent T2D models. In this study, we identified a LDHA-suppressing microRNA (hsa-miR-590-3p and used it together with human embryonic stem cell (hESC derived pancreatic endoderm (PE transplantation into a high-fat diet induced T2D mouse model. The procedure significantly improved glucose metabolism and other symptoms of T2D. Our findings support the potential T2D treatment using the combination of microRNA and hESC-differentiated PE cells.

  8. An antisense oligodeoxynucleotide targeted against the type II sub. beta. regulatory subunit mRNA of protein kinase inhibits cAMP-induced differentiation in HL-60 leukemia cells without affecting phorbol ester effects

    Energy Technology Data Exchange (ETDEWEB)

    Tortora, G.; Clair, T.; Cho-Chung, Y.S. (National Institutes of Health, Bethesda, MD (USA))


    The type II{sub {beta}} regulatory subunit of cAMP-dependent protein kinase (RII{sub {beta}}) has been hypothesized to play an important role in the growth inhibition and differentiation induced by site-selective cAMP analogs in human cancer cells, but direct proof of this function has been lacking. To address this tissue, HL-60 human promyelocytic leukemia cells were exposed to RII{sub {beta}} antisense synthetic oligodeoxynucleotide, and the effects on cAMP-induced growth regulation were examined. Exposure of these cells to RII{sub {beta}} antisense oligodeoxynucleotide resulted in a decrease in cAMP analog-induced growth inhibition and differentiation without apparent effect on differentiation induced by phorbol esters. This loss in cAMP growth regulatory function correlated with a decrease in basal and induced levels of RII{sub {beta}} protein. Exposure to RII{sub {beta}} sense, RI{sub {alpha}} and RII{sub {alpha}} antisense, or irrelevant oligodeoxynucleotides had no such effect. These results show that the RII{sub {beta}} regulatory subunit of protein kinase plays a critical role in the cAMP-induced growth regulation of HL-60 leukemia cells.

  9. Corneal endothelial morphology and central thickness in patients with type II diabetes mellitus

    DEFF Research Database (Denmark)

    Storr-Paulsen, Allan; Singh, Amardeep; Jeppesen, Helene;


    PURPOSE: To investigate corneal endothelial cell density and morphology in type II diabetic and non-diabetic patients and to relate potential differences to the glycaemic status. METHODS: A prospective clinical study including 107 patients with type II diabetes and 128 non-diabetic patients. Samp...

  10. DNA damage and cytotoxicity in type II lung epithelial (A549 cell cultures after exposure to diesel exhaust and urban street particles

    Directory of Open Access Journals (Sweden)

    Møller Peter


    Full Text Available Abstract Background Exposure to air pollution particles has been acknowledged to be associated with excess generation of oxidative damage to DNA in experimental model systems and humans. The use of standard reference material (SRM, such as SRM1650 and SRM2975, is advantageous because experiments can be reproduced independently, but exposure to such samples may not mimic the effects observed after exposure to authentic air pollution particles. This study was designed to compare the DNA oxidizing effects of authentic street particles with SRM1650 and SRM2975. The authentic street particles were collected at a traffic intensive road in Copenhagen, Denmark. Results All of the particles generated strand breaks and oxidized purines in A549 lung epithelial cells in a dose-dependent manner and there were no overt differences in their potency. The exposures also yielded dose-dependent increase of cytotoxicity (as lactate dehydrogenase release and reduced colony forming ability with slightly stronger cytotoxicity of SRM1650 than of the other particles. In contrast, only the authentic street particles were able to generate 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG in calf thymus DNA, which might be due to the much higher level of transition metals. Conclusion Authentic street particles and SRMs differ in their ability to oxidize DNA in a cell-free environment, whereas cell culture experiments indicate that the particle preparations elicit a similar alteration of the level of DNA damage and small differences in cytotoxicity. Although it cannot be ruled out that SRMs and authentic street particles might elicit different effects in animal experimental models, this study indicates that on the cellular level, SRM1650 and SRM2975 are suitable surrogate samples for the study of authentic street particles.

  11. Two endogenous proteins that induce cell wall extension in plants (United States)

    McQueen-Mason, S.; Durachko, D. M.; Cosgrove, D. J.


    Plant cell enlargement is regulated by wall relaxation and yielding, which is thought to be catalyzed by elusive "wall-loosening" enzymes. By employing a reconstitution approach, we found that a crude protein extract from the cell walls of growing cucumber seedlings possessed the ability to induce the extension of isolated cell walls. This activity was restricted to the growing region of the stem and could induce the extension of isolated cell walls from various dicot stems and the leaves of amaryllidaceous monocots, but was less effective on grass coleoptile walls. Endogenous and reconstituted wall extension activities showed similar sensitivities to pH, metal ions, thiol reducing agents, proteases, and boiling in methanol or water. Sequential HPLC fractionation of the active wall extract revealed two proteins with molecular masses of 29 and 30 kD associated with the activity. Each protein, by itself, could induce wall extension without detectable hydrolytic breakdown of the wall. These proteins appear to mediate "acid growth" responses of isolated walls and may catalyze plant cell wall extension by a novel biochemical mechanism.


    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, Yasuhiro [Institute of Astronomy and Astrophysics, Academia Sinica (ASIAA), Taipei 10641, Taiwan (China); Ida, Shigeru, E-mail:, E-mail: [Earth-Life Science Institute, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo 152-8551 (Japan)


    Planetary migration is one of the most serious problems to systematically understand the observations of exoplanets. We clarify that the theoretically predicted type II, migration (like type I migration) is too fast, by developing detailed analytical arguments in which the timescale of type II migration is compared with the disk lifetime. In the disk-dominated regime, the type II migration timescale is characterized by a local viscous diffusion timescale, while the disk lifetime is characterized by a global diffusion timescale that is much longer than the local one. Even in the planet-dominated regime where the inertia of the planet mass reduces the migration speed, the timescale is still shorter than the disk lifetime except in the final disk evolution stage where the total disk mass decays below the planet mass. This suggests that most giant planets plunge into the central stars within the disk lifetime, and it contradicts the exoplanet observations that gas giants are piled up at r {approx}> 1 AU. We examine additional processes that may arise in protoplanetary disks: dead zones, photoevaporation of gas, and gas flow across a gap formed by a type II migrator. Although they make the type II migration timescale closer to the disk lifetime, we show that none of them can act as an effective barrier for rapid type II migration with the current knowledge of these processes. We point out that gas flow across a gap and the fraction of the flow accreted onto the planets are uncertain and they may have the potential to solve the problem. Much more detailed investigation for each process may be needed to explain the observed distribution of gas giants in extrasolar planetary systems.

  13. Efficiency Enhanced Colloidal Mn-Doped Type II Core/Shell ZnSe/CdS Quantum Dot Sensitized Hybrid Solar Cells

    Directory of Open Access Journals (Sweden)

    A. Jamshidi


    Full Text Available Colloidal Mn-doped ZnSe/CdS core/shell quantum dots (QDs are synthesized for the first time and employed as a strategy to boost the power conversion efficiency of quantum dot sensitized solar cells. By using Mn-doping as a band gap engineering tool for core/shell QDs an effective improvement of absorption spectra could be obtained. The mid-states generated by a proper Mn content alleviate carrier separation and enhance the electron injection rate, thus facilitating electron transport to the TiO2 substrate. It is demonstrated that a device constructed with 0.25% Mn-doped ZnSe/CdS leads to an enhancement of the electron injection rate and power conversion efficiency by 4 times and 1.3, respectively.

  14. Fibronectin type II-module proteins in the bovine genital tract and their putative role in cell volume control during sperm maturation. (United States)

    Sahin, Evrim; Petrunkina, Anna M; Ekhlasi-Hundrieser, Mahnaz; Hettel, Christiane; Waberski, Dagmar; Harrison, Robin A P; Töpfer-Petersen, Edda


    The male reproductive tract of ungulates contains two protein families bearing tandemly arranged fibronectin II (Fn2) modules; one (small Fn2 proteins) bears two modules (e.g. BSP-A1/2), the other (long Fn2 proteins) bears four (e.g. epididymal sperm-binding protein 1 (ELSPBP1)). While it is well known that small Fn2 proteins are present in bull semen, nothing is known about long Fn2 proteins. In the present study, the presence of ELSPBP1 proteins in the bull epididymis and their association with maturing spermatozoa were investigated using a specific antibody against canine ELSPBP1. Analysis of western blots showed ELSPBP1 to be present in the caput, corpus and cauda regions of the epididymis. The protein, which bound phosphorylcholine (PC) strongly, appeared to associate with the spermatozoa during maturation because it was absent from caput spermatozoa but present on cauda spermatozoa. Immunocytochemistry of cauda spermatozoa showed the protein to be bound to the post-acrosomal and midpiece regions. ELSPBP1 could not be detected on freshly ejaculated spermatozoa but was revealed after a capacitating treatment. Our previous studies have shown differences between bovine caput and cauda spermatozoa in terms of their ability to control cell volume. Because of the close homology of BSP-A1/2 PC binding regions with Fn2 regions in ELSPBP1, BSP-A1/2 was used as a model to investigate the effect of a PC-binding Fn2 protein on cell volume control. While the protein had no effect on cauda spermatozoa, it caused caput spermatozoa to swell more in response to hypotonic stress, similarly to untreated cauda spermatozoa.

  15. Multidimensional solid-state NMR spectroscopy of plant cell walls. (United States)

    Wang, Tuo; Phyo, Pyae; Hong, Mei


    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 structures and interactions of cellulose and matrix polysaccharides in plant cell walls. These studies have focused on primary cell walls of growing plants in both the dicotyledonous and grass families, as represented by the model plants Arabidopsis thaliana, Brachypodium distachyon, and Zea mays. To date, these SSNMR results have shown that 1) cellulose, hemicellulose, and pectins form a single network in the primary cell wall; 2) in dicot cell walls, the protein expansin targets the hemicellulose-enriched region of the cellulose microfibril for its wall-loosening function; and 3) primary wall cellulose has polymorphic structures that are distinct from the microbial cellulose structures. This article summarizes these key findings, and points out future directions of investigation to advance our fundamental understanding of plant cell wall structure and function.

  16. 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 nucleotides...... probes (monoclonal antibodies mAbs and carbohydrate binding modules, CBMs) to rapidly profile polysaccharides across a sample set. During my PhD I have further developed the CoMPP technique and used it for cell wall analysis within the context of a variety of applied and fundamental projects. The data...... 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...

  17. Cell wall degradation in the autolysis of filamentous fungi. (United States)

    Perez-Leblic, M I; Reyes, F; Martinez, M J; Lahoz, R


    A systematic study on autolysis of the cell walls of fungi has been made on Neurospora crassa, Botrytis cinerea, Polystictus versicolor, Aspergillus nidulans, Schizophyllum commune, Aspergillus niger, and Mucor mucedo. During autolysis each fungus produces the necessary lytic enzymes for its autodegradation. From autolyzed cultures of each fungus enzymatic precipitates were obtained. The degree of lysis of the cell walls, obtained from non-autolyzed mycelia, was studied by incubating these cell walls with and without a supply of their own lytic enzymes. The degree of lysis increased with the incubation time and generally was higher with a supply of lytic enzymes. Cell walls from mycelia of different ages were obtained. A higher degree of lysis was always found, in young cell walls than in older cell walls, when exogenous lytic enzymes were present. In all the fungi studied, there is lysis of the cell walls during autolysis. This is confirmed by the change of the cell wall structure as well as by the degree of lysis reached by the cell wall and the release of substances, principally glucose and N-acetylglucosamine in the medium.

  18. Lipoteichoic acid induces surfactant protein-A biosynthesis in human alveolar type II epithelial cells through activating the MEK1/2-ERK1/2-NF-κB pathway

    Directory of Open Access Journals (Sweden)

    Liu Feng-Lin


    Full Text Available Abstract Background Lipoteichoic acid (LTA, a gram-positive bacterial outer membrane component, can cause septic shock. Our previous studies showed that the gram-negative endotoxin, lipopolysaccharide (LPS, could induce surfactant protein-A (SP-A production in human alveolar epithelial (A549 cells. Objectives In this study, we further evaluated the effect of LTA on SP-A biosynthesis and its possible signal-transducing mechanisms. Methods A549 cells were exposed to LTA. Levels of SP-A, nuclear factor (NF-κB, extracellular signal-regulated kinase 1/2 (ERK1/2, and mitogen-activated/extracellular signal-regulated kinase kinase (MEK1 were determined. Results Exposure of A549 cells to 10, 30, and 50 μg/ml LTA for 24 h did not affect cell viability. Meanwhile, when exposed to 30 μg/ml LTA for 1, 6, and 24 h, the biosynthesis of SP-A mRNA and protein in A549 cells significantly increased. As to the mechanism, LTA enhanced cytosolic and nuclear NF-κB levels in time-dependent manners. Pretreatment with BAY 11–7082, an inhibitor of NF-κB activation, significantly inhibited LTA-induced SP-A mRNA expression. Sequentially, LTA time-dependently augmented phosphorylation of ERK1/2. In addition, levels of phosphorylated MEK1 were augmented following treatment with LTA. Conclusions Therefore, this study showed that LTA can increase SP-A synthesis in human alveolar type II epithelial cells through sequentially activating the MEK1-ERK1/2-NF-κB-dependent pathway.



    Santosh Kumar; Sunil Kumar; Anand


    Waardenburg syndrome is a rare syndrome, characterized by lateral displacement of the medial canthi combined with dystopia of the lacrimal punctum and blepharophimosis, prominent broad nasal root, hypertrichosis of the medial part of the eyebrows, white forelock, heterochromia iridis, and deaf mutism. A four months old girl with waardenburg syndrome type II, who had the characterstic features of the syndrome, is reported.

  20. Neurofibromatosis type II presenting as vertical diplopia. (United States)

    Sokwala, Ahmed; Knapp, Christopher; Gottlob, Irene


    Neurofibromatosis type II (NF II) is rare and most commonly presents with hearing loss, tinnitus and/or vestibular disturbance in the third decade of life. The authors describe a rare case presenting with NF II with vertical diplopia due to IV(th) nerve palsy. The patient was otherwise asymptomatic despite multiple extensive lesions on MRI.

  1. Generalized geometry lectures on type II backgrounds

    CERN Document Server

    Tsimpis, Dimitrios


    The first part of these notes is a self-contained introduction to generalized complex geometry. It is intended as a `user manual' for tools used in the study of supersymmetric backgrounds of supergravity. In the second part we review some past and recent results on the generalized complex structure of supersymmetric type II vacua in various dimensions.

  2. Measuring type II stresses using 3DXRD

    DEFF Research Database (Denmark)

    Oddershede, Jette; Schmidt, Søren; Poulsen, Henning Friis;


    An algorithm is presented for characterization of the grain resolved (type II) stress states in a polycrystalline sample based on monochromatic X-ray diffraction data. The algorithm is a robust 12-parameter-per-grain fit of the centre-of-mass grain positions, orientations and stress tensors...

  3. Biceps Tenodesis for Type II SLAP Tears. (United States)

    Tayrose, Gregory A; Karas, Spero G; Bosco, Joseph


    Tears of the superior glenoid labrum are a common cause of shoulder pain and disability, especially in overhead athletes such as pitchers, swimmers, and volleyball players. Type II SLAP lesions have been the most clinically important superior labral pathology, and the management of this lesion has been a very controversial topic. Currently, there are no high level studies in the literature to guide treatment. While the few level 3 and level 4 evidence studies that are available following arthroscopic repair of type II SLAP lesions all report reasonable overall patient satisfaction, persistent postoperative pain is common and associated with a low return to pre-injury level of sports participation. There has been a recent school of thought that biceps tenodesis, which maintains the length-tension relationship of the long head of biceps, should be the procedure of choice for patients with isolated type II SLAP lesions. The current paper reviews the role biceps tenodesis plays in the management of type II SLAP tears.

  4. Small molecule probes for plant cell wall polysaccharide imaging

    Directory of Open Access Journals (Sweden)

    Ian eWallace


    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.

  5. Mechanical Properties of Plant Cell Walls Probed by Relaxation Spectra

    DEFF Research Database (Denmark)

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


    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...... type. This may be due to the plant’s ability to compensate for the wall modification or because the biophysical method that is often employed, determination of simple elastic modulus and breakstrength, lacks the resolving power necessary for detecting subtle mechanical phenotypes. Here, we apply...... a method, determination of relaxation spectra, which probes, and can separate, the viscoelastic properties of different cell wall components (i.e. those properties that depend on the elastic behavior of load-bearing wall polymers combined with viscous interactions between them). A computer program, Bayes...

  6. Reproducible isolation of type II pneumocytes from fetal and adult rat lung using nycodenz density gradients. (United States)

    Viscardi, R M; Ullsperger, S; Resau, J H


    Isolating fresh, relatively pure type II pneumocytes from the lung, particularly of fetal origin, is a difficult process. Separation by buoyant density gradient centrifugation has been used successfully to isolate adult type II cells. There is concern, however, that Percoll, a gradient medium that is commonly used for type II cell isolation, may be toxic to cells. We evaluated a new gradient medium, Nycodenz, that is (1) a true solution, (2) transparent, (3) not metabolized by cells, and (4) nontoxic to cells. Type II pneumocytes were isolated from 19- and 21-day gestation fetal and adult rat lung by elastase digestion and separated on preformed isotonic Nycodenz gradients (2 mL each of 27.6, 20.7, 13.8, and 4.6 (w/v) solutions). Type II pneumocytes were recovered from the density range 1.057-1.061 and identified by binding of FITC-conjugated and gold-complexed Maclura pomifera lectin. Cells derived from 19-day fetal lung contained abundant glycogen and reacted with a monoclonal antibody to the cytokeratins 8 and 18, which are markers of the fetal type II cell. Adult type II cells reacted with antibodies to cytokeratins 8, 18, and 19. Type II cell purity was 79.7 +/- 2.4%, 83.8 +/- 2.8%, and 82.6 +/- 1.8% (means +/- SEM) for 19- and 21-day gestation fetal and adult lung preparations, respectively. Cell viability was greater than 95%. The final cell yield for adult preparations was 17.8 +/- 2.7 x 10(6)/rat (means +/- SEM). To determine if the freshly isolated type II pneumocytes were functionally active, the incorporation of [3H]choline into phosphatidylcholine was measured. The percent saturation of phosphatidylcholine was high for both populations of freshly isolated cells. However, adult type II pneumocytes incorporated [3H]choline into phosphatidylcholine more rapidly than 21-day gestation fetal cells (5.97 x 10(-3) dpm/10(6) cells/h vs. 0.32 x 10(-3) dpm/10(6) cells/h, P less than .005). We have demonstrated that, using the Nycodenz isolation method, it is

  7. Infection of A549 human type II epithelial cells with Mycobacterium tuberculosis induces changes in mitochondrial morphology, distribution and mass that are dependent on the early secreted antigen, ESAT-6. (United States)

    Fine-Coulson, Kari; Giguère, Steeve; Quinn, Frederick D; Reaves, Barbara J


    Pulmonary infection by Mycobacterium tuberculosis (Mtb) involves the invasion of alveolar epithelial cells (AECs). We used Mitotracker Red(®) to assess changes in mitochondrial morphology/distribution and mass from 6 to 48 h post infection (hpi) by confocal microscopy and flow cytometry in Mtb-infected A549 type II AECs. During early infection there was no effect on mitochondrial morphology, however, by 48 hpi mitochondria appeared fragmented and concentrated around the nucleus. In flow cytometry experiments, the median fluorescence intensity (MFI) decreased by 44% at 48 hpi; double-labelling using antibodies to the integral membrane protein COXIV revealed that these changes were due to a decrease in mitochondrial mass. These changes did not occur with the apathogenic strain, Mycobacterium bovis BCG. ESAT-6 is a virulence factor present in Mtb Erdman but lacking in M. bovis BCG. We performed similar experiments using Mtb Erdman, an ESAT-6 deletion mutant and its complement. MFI decreased at 48 hpi in the parent and complemented strains versus uninfected controls by 52% and 36% respectively; no decrease was detected in the deletion mutant. These results indicate an involvement of ESAT-6 in the perturbation of mitochondria induced by virulent Mtb in AECs and suggest mitophagy may play a role in the infection process.

  8. KRAS and MAPK1 Gene Amplification in Type II Ovarian Carcinomas

    Directory of Open Access Journals (Sweden)

    Noriyuki Ishikawa


    Full Text Available In this study, we examined the clinical significance of KRAS and MAPK1 amplification and assessed whether these amplified genes were potential therapeutic targets in type II ovarian carcinoma. Using fluorescence in situ hybridization, immunohistochemistry, and retrospectively collected clinical data, KRAS and MAPK1 amplifications were identified in 9 (13.2% and 5 (7.4% of 68 type II ovarian carcinoma tissue samples, respectively. Interestingly, co-amplification of KRAS and MAPK1 seemed to be absent in the type II ovarian carcinomas tested, except one case. Active phospho-ERK1/2 was identified in 26 (38.2% out of 68 type II ovarian carcinomas and did not correlate with KRAS or MAPK1 amplification. There was no significant relationship between KRAS amplification and overall or progression-free survival in patients with type II ovarian carcinoma. However, patients with MAPK1 amplification had significantly poorer progression-free survival than patients without MAPK1 amplification. Moreover, type II ovarian carcinoma cells with concomitant KRAS amplification and mutation exhibited dramatic growth reduction following treatment with the MEK inhibitor PD0325901. These findings indicate that KRAS/MAPK1 amplification is critical for the growth of a subset of type II ovarian carcinomas. Additionally, RAS/RAF/MEK/ERK pathway-targeted therapy may benefit selected patients with type II ovarian carcinoma harboring KRAS/MAPK1 amplifications.

  9. 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)


    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.

  10. Characterising the cellulose synthase complexes of cell walls

    NARCIS (Netherlands)

    Mansoori Zangir, N.


    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 c

  11. Hemicellulose biosynthesis and degradation in tobacco cell walls

    NARCIS (Netherlands)

    Compier, M.G.M.


    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

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

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida


    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.

  13. Type II Supernovae as Probes of Cosmology

    CERN Document Server

    Poznanski, Dovi; Blondin, Stephane; Bloom, Joshua S; D'Andrea, Christopher B; Della Valle, Massimo; Dessart, Luc; Ellis, Richard S; Gal-Yam, Avishay; Goobar, Ariel; Hamuy, Mario; Hicken, Malcolm; Kasen, Daniel N; Krisciunas, Kevin L; Leonard, Douglas C; Li, Weidong; Livio, Mario; Marion, Howie; Matheson, Thomas; Neill, James D; Nomoto, Ken'ichi; Nugent, Peter E; Quimby, Robert; Sako, Masao; Sullivan, Mark; Thomas, Rollin C; Turatto, Massimo; Van Dyk, Schuyler D; Wood-Vasey, W Michael


    - Constraining the cosmological parameters and understanding Dark Energy have tremendous implications for the nature of the Universe and its physical laws. - The pervasive limit of systematic uncertainties reached by cosmography based on Cepheids and Type Ia supernovae (SNe Ia) warrants a search for complementary approaches. - Type II SNe have been shown to offer such a path. Their distances can be well constrained by luminosity-based or geometric methods. Competing, complementary, and concerted efforts are underway, to explore and exploit those objects that are extremely well matched to next generation facilities. Spectroscopic follow-up will be enabled by space- based and 20-40 meter class telescopes. - Some systematic uncertainties of Type II SNe, such as reddening by dust and metallicity effects, are bound to be different from those of SNe Ia. Their stellar progenitors are known, promising better leverage on cosmic evolution. In addition, their rate - which closely tracks the ongoing star formation rate -...

  14. VLBI observations of young Type II supernovae

    CERN Document Server

    Pérez-Torres, M A; Marcaide, J M


    We give an overview of circumstellar interaction in young Type II supernovae, as seen through the eyes of very-long-baseline interferometry (VLBI) observations. The resolution attained by such observations (best than 1 mas) is a powerful tool to probe the interaction that takes place after a supernova goes off. The direct imaging of a supernova permits, in principle, to estimate the deceleration of its expansion, and to obtain information on the eject and circumstellar density profiles, as well as estimates of the magnetic field intensity and relativistic particle energy density in the supernova. Unfortunately, only a handful of radio supernovae are close and bright enough as to permit their study with VLBI. We present results from our high-resolution observations of the nearby Type II radio supernovae SN1986J and SN2001gd.

  15. On-Off Switches for Secondary Cell Wall Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Huan-Zhong Wang; Richard A.Dixon


    Secondary cell walls provide plants with rigidity and strength to support their body weight and ensure water and nutrient transport.They also provide textiles,timber,and potentially second-generation biofuels for human use.Genes responsible for synthesis of the different cell wall components,namely cellulose,hemicelluloses,and lignin,are coordinately expressed and under transcriptional regulation.In the past several years,cell wall-related NAC and MYB transcription factors have been intensively investigated in different species and shown to be master switches of secondary cell wall biosynthesis.Positive and negative regulators,which function upstream of NAC master switches,have also been identified in different plant tissues.Further elucidation of the regulatory mechanisms of cell wall synthesis will facilitate the engineering of plant feedstocks suitable for biofuel production.

  16. Exciton in type-II quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Sierra-Ortega, J; Escorcia, R A [Universidad del Magdalena, A. A. 731, Santa Marta (Colombia); Mikhailov, I D, E-mail: [Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia)


    We study the quantum-size effect and the influence of the external magnetic field on the exciton ground state energy in the type-II InP quantum disk, lens and pyramid deposited on a wetting layer and embedded in a GaInP matrix. We show that the charge distribution over and below quantum dot and wetting layer induced by trapped exciton strongly depends on the quantum dot morphology and the strength of the magnetic field.


    Directory of Open Access Journals (Sweden)

    Santosh Kumar


    Full Text Available Waardenburg syndrome is a rare syndrome, characterized by lateral displacement of the medial canthi combined with dystopia of the lacrimal punctum and blepharophimosis, prominent broad nasal root, hypertrichosis of the medial part of the eyebrows, white forelock, heterochromia iridis, and deaf mutism. A four months old girl with waardenburg syndrome type II, who had the characterstic features of the syndrome, is reported.

  18. Peculiar Type II Supernovae from Blue Supergiants

    CERN Document Server

    Kleiser, Io K W; Kasen, Daniel; Young, Timothy R; Chornock, Ryan; Filippenko, Alexei V; Challis, Peter; Ganeshalingam, Mohan; Kirshner, Robert P; Li, Weidong; Matheson, Thomas; Nugent, Peter E; Silverman, Jeffrey M


    The vast majority of Type II supernovae (SNe) are produced by red supergiants (RSGs), but SN 1987A revealed that blue supergiants (BSGs) can produce members of this class as well, albeit with some peculiar properties. This best studied event revolutionized our understanding of SNe, and linking it to the bulk of Type II events is essential. We present here optical photometry and spectroscopy gathered for SN 2000cb, which is clearly not a standard Type II SN and yet is not a SN 1987A analog. The light curve of SN 2000cb is reminiscent of that of SN 1987A in shape, with a slow rise to a late optical peak, but on substantially different time scales. Spectroscopically, SN 2000cb resembles a normal SN II but with ejecta velocities that far exceed those measured for SN 1987A or normal SNe II, above 18000 km/s for H-alpha at early times. The red colours, high velocities, late photometric peak, and our modeling of this object all point toward a scenario involving the high-energy explosion of a small-radius star, most ...

  19. Dynamic metabolic flux analysis of plant cell wall synthesis. (United States)

    Chen, Xuewen; Alonso, Ana P; Shachar-Hill, Yair


    The regulation of plant cell wall synthesis pathways remains poorly understood. This has become a bottleneck in designing bioenergy crops. The goal of this study was to analyze the regulation of plant cell wall precursor metabolism using metabolic flux analysis based on dynamic labeling experiments. Arabidopsis T87 cells were cultured heterotrophically with (13)C labeled sucrose. The time course of ¹³C labeling patterns in cell wall precursors and related sugar phosphates was monitored using liquid chromatography tandem mass spectrometry until steady state labeling was reached. A kinetic model based on mass action reaction mechanisms was developed to simulate the carbon flow in the cell wall synthesis network. The kinetic parameters of the model were determined by fitting the model to the labeling time course data, cell wall composition, and synthesis rates. A metabolic control analysis was performed to predict metabolic regulations that may improve plant biomass composition for biofuel production. Our results describe the routes and rates of carbon flow from sucrose to cell wall precursors. We found that sucrose invertase is responsible for the entry of sucrose into metabolism and UDP-glucose-4-epimerase plays a dominant role in UDP-Gal synthesis in heterotrophic Aradidopsis cells under aerobic conditions. We also predicted reactions that exert strong regulatory influence over carbon flow to cell wall synthesis and its composition.

  20. Maize development: cell wall changes in leaves and sheaths (United States)

    Developmental changes occur in maize (Zea mays L.) as it transitions from juvenile stages to the mature plant. Changes also occur as newly formed cells mature into adult cells. Maize leaf blades, including the midribs and sheaths, undergo cell wall changes as cells transition to fully mature cell ty...

  1. Cell Wall Metabolism in Response to Abiotic Stress

    Directory of Open Access Journals (Sweden)

    Hyacinthe Le Gall


    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.

  2. NNMSM type-II and -III

    Energy Technology Data Exchange (ETDEWEB)

    Haba, Naoyuki [Graduate School of Science and Engineering, Shimane University, Matsue, Shimane (Japan); Hokkaido University, Department of Physics, Faculty of Science, Sapporo, Hokkaido (Japan); Kaneta, Kunio [Hokkaido University, Department of Physics, Faculty of Science, Sapporo, Hokkaido (Japan); University of Tokyo, Kavli Institute for the Physics and Mathematics of the Universe (WPI), Kashiwa, Chiba (Japan); Osaka University, Department of Physics, Graduate School of Science, Toyonaka, Osaka (Japan); Takahashi, Ryo [Hokkaido University, Department of Physics, Faculty of Science, Sapporo, Hokkaido (Japan)


    We suggest two types of extension of the standard model, which are the so-called next to new minimal standard model type-II and -III. They can achieve gauge coupling unification as well as suitable dark matter abundance, small neutrino masses, baryon asymmetry of the universe, inflation, and dark energy. The gauge coupling unification can be realized by introducing two or three extra new fields, and they could explain charge quantization. We also show that there are regions in which the vacuum stability, coupling perturbativity, and correct dark matter abundance can be realized with current experimental data at the same time. (orig.)

  3. 2D-immunoblotting analysis of Sporothrix schenckii cell wall

    Directory of Open Access Journals (Sweden)

    Estela Ruiz-Baca


    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.

  4. Up against the wall: is yeast cell wall integrity ensured by mechanosensing in plasma membrane microdomains? (United States)

    Kock, Christian; Dufrêne, Yves F; Heinisch, Jürgen J


    Yeast cell wall integrity (CWI) signaling serves as a model of the regulation of fungal cell wall synthesis and provides the basis for the development of antifungal drugs. A set of five membrane-spanning sensors (Wsc1 to Wsc3, Mid2, and Mtl1) detect cell surface stress and commence the signaling pathway upon perturbations of either the cell wall structure or the plasma membrane. We here summarize the latest advances in the structure/function relationship primarily of the Wsc1 sensor and critically review the evidence that it acts as a mechanosensor. The relevance and physiological significance of the information obtained for the function of the other CWI sensors, as well as expected future developments, are discussed.

  5. Notch maintains Drosophila type II neuroblasts by suppressing expression of the Fez transcription factor Earmuff. (United States)

    Li, Xiaosu; Xie, Yonggang; Zhu, Sijun


    Notch signaling is crucial for maintaining neural stem cell (NSC) self-renewal and heterogeneity; however, the underlying mechanism is not well understood. In Drosophila, loss of Notch prematurely terminates the self-renewal of larval type II neuroblasts (NBs, the Drosophila NSCs) and transforms type II NBs into type I NBs. Here, we demonstrate that Notch maintains type II NBs by suppressing the activation of earmuff (erm) by Pointed P1 (PntP1). We show that loss of Notch or components of its canonical pathway leads to PntP1-dependent ectopic Erm expression in type II NBs. Knockdown of Erm significantly rescues the loss-of-Notch phenotypes, and misexpression of Erm phenocopies the loss of Notch. Ectopically expressed Erm promotes the transformation of type II NBs into type I NBs by inhibiting PntP1 function and expression in type II NBs. Our work not only elucidates a key mechanism of Notch-mediated maintenance of type II NB self-renewal and identity, but also reveals a novel function of Erm.

  6. 骨髓源性肥大细胞对软骨细胞表达Ⅱ型胶原及糖胺多糖的影响%Effects of bone marrow- derived mast cells on expressions of type II collagen and glycosaminoglycan in co-cultured chondrocytes

    Institute of Scientific and Technical Information of China (English)

    欧阳晴晴; 赵进军; 杨敏


    Objective To investigate the influence of the bone marrow-derived mast cells (BMMCs) on the expression of type II collagen and glycosaminoglycan (GAG) in chondrocytes co-cultured with BMMCs. Methods Primarily cultured mouse BMMCs at 4 weeks and the second passage of chondrocytes were plated in a Transwell co-cultured system at a ratio of 1∶10 in the presence or absence of sodium cromoglycate (DSCG) or compound 48/80 (C48/80). The chondrocytes were harvested and lysed for detecting type II collagen expression with ELISA and Western blotting and GAG expression using 1,9 dimethylmethylene blue (DBM). Results After a 24-hour culture, the chondrocytes co-cultured with BMMCs showed similar expression levels of type II collagen and GAG to the control group regardless of the presence of DSCG (P>0.05). Compared with chondrocytes cultured alone or with BMMCs, the co- cultured chondrocytes in the presence of C48/80 showed significantly lower expressions of type II collagen and GAG (P0.05),C48/80组Ⅱ型胶原与GAG含量相对于对照组和BMMCs组显著降低(P0.05)。结论C48/80激活的BMMCs可降低软骨细胞Ⅱ型胶原以及GAG表达。

  7. Cell wall-associated malate dehydrogenase activity from maize roots. (United States)

    Hadži-Tašković Šukalović, Vesna; Vuletić, Mirjana; Marković, Ksenija; Vučinić, Zeljko


    Isolated cell walls from maize (Zea mays L.) roots exhibited ionically and covalently bound NAD-specific malate dehydrogenase activity. The enzyme catalyses a rapid reduction of oxaloacetate and much slower oxidation of malate. The kinetic and regulatory properties of the cell wall enzyme solubilized with 1M NaCl were different from those published for soluble, mitochondrial or plasma membrane malate dehydrogenase with respect to their ATP, Pi, and pH dependence. Isoelectric focusing of ionically-bound proteins and specific staining for malate dehydrogenase revealed characteristic isoforms present in cell wall isolate, different from those present in plasma membranes and crude homogenate. Much greater activity of cell wall-associated malate dehydrogenase was detected in the intensively growing lateral roots compared to primary root with decreased growth rates. Presence of Zn(2+) and Cu(2+) in the assay medium inhibited the activity of the wall-associated malate dehydrogenase. Exposure of maize plants to excess concentrations of Zn(2+) and Cu(2+) in the hydroponic solution inhibited lateral root growth, decreased malate dehydrogenase activity and changed isoform profiles. The results presented show that cell wall malate dehydrogenase is truly a wall-bound enzyme, and not an artefact of cytoplasmic contamination, involved in the developmental processes, and detoxification of heavy metals.

  8. Impact of diabetes type II and chronic inflammation on pancreatic cancer


    Zechner, Dietmar; Radecke, Tobias; Amme, Jonas; Bürtin, Florian; Albert, Ann-Christin; Partecke, Lars Ivo; Vollmar, Brigitte


    Background We explored if known risk factors for pancreatic cancer such as type II diabetes and chronic inflammation, influence the pathophysiology of an established primary tumor in the pancreas and if administration of metformin has an impact on tumor growth. Methods Pancreatic carcinomas were assessed in a syngeneic orthotopic pancreas adenocarcinoma model after injection of 6606PDA cells in the pancreas head of either B6.V-Lepob/ob mice exhibiting a type II diabetes-like syndrome or normo...

  9. Fetuin-A and type II diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Lamyaa Ismail Ahmed


    Conclusion We concluded that fetuin-A may play a role in the pathogenesis of type II DM, and high serum fetuin-A has a strong association with IR and glycemic control in type II diabetic patients. Future studies are recommended to establish the possibility of using fetuin-A as a predictor of insulin resistance in type II diabetic patients.

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

    Directory of Open Access Journals (Sweden)

    Lima D.U.


    Full Text Available Our search for genes related to cell wall metabolism in the sugarcane expressed sequence tag (SUCEST database ( 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

  11. Pectin, a versatile polysaccharide present in plant cell walls

    NARCIS (Netherlands)

    Voragen, A.G.J.; Coenen, G.J.; Verhoef, R.P.; Schols, H.A.


    Pectin or pectic substances are collective names for a group of closely associated polysaccharides present in plant cell walls where they contribute to complex physiological processes like cell growth and cell differentiation and so determine the integrity and rigidity of plant tissue. They also pla

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

    NARCIS (Netherlands)

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


    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,

  13. Cell wall deposition during morphogenesis in fucoid algae. (United States)

    Bisgrove, S R; Kropf, D L


    Cell was deposition was investigated during morphogenesis in zygotes of Pelvetia compressa (J. Agardh) De Toni. Young zygotes are spherical and wall is deposited uniformly, but at germination (about 10 h after fertilization) wall deposition becomes localized to the apex of the tip-growing rhizoid. Wall deposition was investigated before and after the initiation of tip growth by disrupting cytoskeleton, secretion or cellulose deposition; effects on wall strength and structure were examined. All three were involved in generating wall strength in both spherical and tip-growing zygotes, but their relative importance were different at the two developmental stages. Much of the wall strength in young zygotes was dependent on F-actin, whereas cellulose and a sulfated component, probably a fucan (F2), were most important in tip growing zygotes. Some treatments had contrasting effects at the two developmental stages; for example, disruption of F-actin or inhibition of secretion weakened walls in spherical zygotes but strengthened those in tip-growing zygotes. Transmission electron microscopic analysis showed that most treatments that altered wall strength induced modifications of internal wall structure.

  14. Role of the plant cell wall in gravity resistance. (United States)

    Hoson, Takayuki; Wakabayashi, Kazuyuki


    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.

  15. Type II supernovae Early Light Curves

    CERN Document Server

    Shussman, Tomer; Nakar, Ehud


    Observations of type II supernova early light, from breakout until recombination, can be used to constrain the explosion energy and progenitor properties. Currently available for this purpose are purely analytic models, which are accurate only to within an order of magnitude, and detailed numerical simulations, which are more accurate but are applied to any event separately. In this paper we derive an analytic model that is calibrated by numerical simulations. This model is much more accurate than previous analytic models, yet it is as simple to use. To derive the model we analyze simulated light curves from numerical explosion of $124$ red supergiant progenitors, calculated using the stellar evolution code MESA. We find that although the structure of the progenitors we consider varies, the resulting light curves can be described rather well based only on the explosion energy, ejecta mass and progenitor radius. Our calibrated analytic model, which is based on these three parameters, reproduces the bolometric ...

  16. Sorption of volatile phenols by yeast cell walls

    Directory of Open Access Journals (Sweden)

    Nerea Jiménez-Moreno


    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

  17. 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


    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

  18. A model for cell wall dissolution in mating yeast cells: polarized secretion and restricted diffusion of cell wall remodeling enzymes induces local dissolution.

    Directory of Open Access Journals (Sweden)

    Lori B Huberman

    Full Text Available Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells.

  19. A model for cell wall dissolution in mating yeast cells: polarized secretion and restricted diffusion of cell wall remodeling enzymes induces local dissolution. (United States)

    Huberman, Lori B; Murray, Andrew W


    Mating of the budding yeast, Saccharomyces cerevisiae, occurs when two haploid cells of opposite mating types signal using reciprocal pheromones and receptors, grow towards each other, and fuse to form a single diploid cell. To fuse, both cells dissolve their cell walls at the point of contact. This event must be carefully controlled because the osmotic pressure differential between the cytoplasm and extracellular environment causes cells with unprotected plasma membranes to lyse. If the cell wall-degrading enzymes diffuse through the cell wall, their concentration would rise when two cells touched each other, such as when two pheromone-stimulated cells adhere to each other via mating agglutinins. At the surfaces that touch, the enzymes must diffuse laterally through the wall before they can escape into the medium, increasing the time the enzymes spend in the cell wall, and thus raising their concentration at the point of attachment and restricting cell wall dissolution to points where cells touch each other. We tested this hypothesis by studying pheromone treated cells confined between two solid, impermeable surfaces. This confinement increases the frequency of pheromone-induced cell death, and this effect is diminished by reducing the osmotic pressure difference across the cell wall or by deleting putative cell wall glucanases and other genes necessary for efficient cell wall fusion. Our results support the model that pheromone-induced cell death is the result of a contact-driven increase in the local concentration of cell wall remodeling enzymes and suggest that this process plays an important role in regulating cell wall dissolution and fusion in mating cells.

  20. Spectral modeling of Type II SNe (United States)

    Dessart, Luc


    The red supergiant phase represents the final stage of evolution in the life of moderate mass (8-25Msun) massive stars. Hidden from view, the core changes considerably its structure, progressing through the advanced stages of nuclear burning, and eventually becomes degenerate. Upon reaching the Chandrasekhar mass, this Fe or ONeMg core collapses, leading to the formation of a proto neutron star. A type II supernova results if the shock that forms at core bounce, eventually wins over the envelope accretion and reaches the progenitor surface.The electromagnetic display of such core-collapse SNe starts with this shock breakout, and persists for months as the ejecta releases the energy deposited initially by the shock or continuously through radioactive decay. Over a timescale of weeks to months, the originally optically-thick ejecta thins out and turns nebular. SN radiation contains a wealth of information about the explosion physics (energy, explosive nucleosynthesis), the progenitor properties (structure and composition). Polarised radiation also offers signatures that can help constrain the morphology of the ejecta.In this talk, I will review the current status of type II SN spectral modelling, and emphasise that a proper solution requires a time dependent treatment of the radiative transfer problem. I will discuss the wealth of information that can be gleaned from spectra as well as light curves, from both the early times (photospheric phase) and late times (nebular phase). I will discuss the diversity of Type SNe properties and how they are related to the diversity of red supergiant stars from which they originate.SN radiation offers an alternate means of constraining the properties of red-supergiant stars. To wrap up, I will illustrate how SNe II-P can also be used as probes, for example to constrain the metallicity of their environment.

  1. Another brick in the cell wall: biosynthesis dependent growth model. (United States)

    Barbacci, Adelin; Lahaye, Marc; Magnenet, Vincent


    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.

  2. 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.

  3. Altered cell wall disassembly during ripening of Cnr tomato fruit : implications for cell wall adhesion and fruit softening

    NARCIS (Netherlands)

    Orfila, C.; Huisman, M.M.H.; Willats, W.G.T.; Alebeek, van G.J.W.M.; Schols, H.A.; Seymour, G.B.; Knox, J.P.


    The Cnr (Colourless non-ripening) tomato (Lycopersicon esculentum Mill.) mutant has an aberrant fruit-ripening phenotype in which fruit do not soften and have reduced cell adhesion between pericarp cells. Cell walls from Cnr fruit were analysed in order to assess the possible contribution of pectic

  4. Primary Cell Wall Structure in the Evolution of Land Plants

    Institute of Scientific and Technical Information of China (English)


    Investigation of the primary cell walls of lower plants improves our understanding of the cell biology of these organisms but also has the potential to improve our understanding of cell wall structure and function in angiosperms that evolved from lower plants. Cell walls were prepared from eight species, ranging from a moss to advanced gymnosperms, and subjected to sequential chemical extraction to separate the main polysaccharide fractions. The glycosyl compositions of these fractions were then determined by gas chromatography. The results were compared among the eight plants and among data from related studies reported in the existing published reports to identify structural features that have been either highly conserved or clearly modified during evolution. Among the highly conserved features are the presence of a cellulose framework, the presence of certain hemicelluloses such as xyloglucan, and the presence of rhamnogalacturonan Ⅱ, a domain in pectic polysaccharides. Among the modified features are the abundance of mannosyl-containing hemicelluloses and the presence of methylated sugars.

  5. Magnetic domain wall conduits for single cell applications

    DEFF Research Database (Denmark)

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


    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...... generated in micro- and nano-structures fabricated on a chip surface can be used to handle single yeast cells labeled with magnetic beads. In detail, first we show that the proposed approach maintains the microorganism viable, as proven by monitoring the division of labeled yeast cells trapped by domain...... walls over 16 hours. Moreover, we demonstrate the controlled transport and release of individual yeast cells via displacement and annihilation of individual domain walls in micro- and nano-sized magnetic structures. These results pave the way to the implementation of magnetic devices based on domain...

  6. Simulated microgravity inhibits cell wall regeneration of Penicillium decumbens protoplasts (United States)

    Zhao, C.; Sun, Y.; Yi, Z. C.; Rong, L.; Zhuang, F. Y.; Fan, Y. B.


    This work compares cell wall regeneration from protoplasts of the fungus Penicillium decumbens under rotary culture (simulated microgravity) and stationary cultures. Using an optimized lytic enzyme mixture, protoplasts were successfully released with a yield of 5.3 × 10 5 cells/mL. Under simulated microgravity conditions, the protoplast regeneration efficiency was 33.8%, lower than 44.9% under stationary conditions. Laser scanning confocal microscopy gave direct evidence for reduced formation of polysaccharides under simulated conditions. Scanning electron microscopy showed the delayed process of cell wall regeneration by simulated microgravity. The delayed regeneration of P. decumbens cell wall under simulated microgravity was likely caused by the inhibition of polysaccharide synthesis. This research contributes to the understanding of how gravitational loads affect morphological and physiological processes of fungi.

  7. Analyzing Cell Wall Elasticity After Hormone Treatment: An Example Using Tobacco BY-2 Cells and Auxin. (United States)

    Braybrook, Siobhan A


    Atomic force microscopy, and related nano-indentation techniques, is a valuable tool for analyzing the elastic properties of plant cell walls as they relate to changes in cell wall chemistry, changes in development, and response to hormones. Within this chapter I will describe a method for analyzing the effect of the phytohormone auxin on the cell wall elasticity of tobacco BY-2 cells. This general method may be easily altered for different experimental systems and hormones of interest.

  8. Diffusion of an organic cation into root cell walls. (United States)

    Meychik, N R; Yermakov, I P; Prokoptseva, O S


    Uptake of a cationic dye (methylene blue) by isolated root cell walls, roots of whole transpiring seedlings, and excised roots was investigated using 7-day-old seedlings of cucumber, maize, and wheat. The number of ionogenic groups per 1 g dry and wet weight of the root cell walls, their swelling capacity (K(cw)), time-dependence of methylene blue (M(cw)) ion exchange capacity, and diffusion coefficients of the cation diffusion in the polymer matrix of the cell walls (D(cw)) were determined. The M(cw) value depended on pH (or carboxyl group dissociation); it changed in accordance with the number of carboxyl groups per 1 g cell wall dry weight. This parameter decreased in the order: cucumber > wheat > maize. For description of experimental kinetic curves and calculation of cation diffusion coefficients, the equation for ion diffusion into a cylinder of infinite length was used. The chosen model adequately described cation diffusion in cell walls and roots. Diffusion coefficient values for cucumber, wheat, and maize were 3.1*10(-8), 1.3*10(-8), and 8.4*10(-8) cm(2)/sec, respectively. There was a statistically significant linear dependence between K(cw) and D(cw) values, which characterize the same property of the polymer matrix, rigidity of its polymer structure or the degree of cross-linkage or permeability. This also confirms the right choice of the model selected for calculation of methylene blue diffusion coefficients, because K(cw) and D(cw) values were obtained in independent experiments. The coefficients determined for methylene blue diffusion in transpiring seedling roots (D(ts)) and excised roots (D(er)) depended on the plant species. The rate of methylene blue diffusion into the excised roots was either 1.5-fold lower (cucumber) or 3-4-times lower (maize, wheat) than in cell walls. The values of diffusion coefficients in roots of whole seedlings were comparable which those for the cell walls. On the basis of the experimental data and results of calculations

  9. Growth and cell wall changes in rice roots during spaceflight. (United States)

    Hoson, Takayuki; Soga, Kouichi; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Tanimoto, Eiichi


    We analyzed the changes in growth and cell wall properties of roots of rice (Oryza sativa L. cv. Koshihikari) grown for 68.5, 91.5, and 136 h during the Space Shuttle STS-95 mission. In space, most of rice roots elongated in a direction forming a constant mean angle of about 55 degrees with the perpendicular base line away from the caryopsis in the early phase of growth, but later the roots grew in various directions, including away from the agar medium. In space, elongation growth of roots was stimulated. On the other hand, some of elasticity moduli and viscosity coefficients were higher in roots grown in space than on the ground, suggesting that the cell wall of space-grown roots has a lower capacity to expand than the controls. The levels of both cellulose and the matrix polysaccharides per unit length of roots decreased greatly, whereas the ratio of the high molecular mass polysaccharides in the hemicellulose fraction increased in space-grown roots. The prominent thinning of the cell wall could overwhelm the disadvantageous changes in the cell wall mechanical properties, leading to the stimulation of elongation growth in rice roots in space. Thus, growth and the cell wall properties of rice roots were strongly modified under microgravity conditions during spaceflight.

  10. The Structure of Plant Cell Walls: II. The Hemicellulose of the Walls of Suspension-cultured Sycamore Cells. (United States)

    Bauer, W D; Talmadge, K W; Keegstra, K; Albersheim, P


    The molecular structure, chemical properties, and biological function of the xyloglucan polysaccharide isolated from cell walls of suspension-cultured sycamore (Acer pseudoplatanus) cells are described. The sycamore wall xyloglucan is compared to the extracellular xyloglucan secreted by suspension-cultured sycamore cells into their culture medium and is also compared to the seed "amyloid" xyloglucans.Xyloglucan-or fragments of xyloglucan-and acidic fragments of the pectic polysaccharides are released from endopolygalacturonase-pretreated sycamore walls by treatment of these walls with 8 m urea, endoglucanase, or 0.5 n NaOH. Some of the xyloglucan thus released is found to cochromatograph with the acidic pectic fragments on diethylaminoethyl Sephadex. The chemical or enzymic treatments required for the release of xyloglucan from the walls and the cochromatography of xyloglucan with the acidic pectic fragments indicate that xyloglucan is covalently linked to the pectic polysaccharides and is noncovalently bound to the cellulose fibrils of the sycamore cell wall.The molecular structure of sycamore xyloglucan was characterized by methylation analysis of the oligosaccharides obtained by endoglucanase treatment of the polymer. The structure of the polymer is based on a repeating heptasaccharide unit which consists of 4 residues of beta-1-4-linked glucose and 3 residues of terminal xylose. A single xylose residue is glycosidically linked to carbon 6 of 3 of the glucosyl residues.

  11. Transcriptional Wiring of Cell Wall-Related Genes in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Marek Mutwil; Colin Ruprecht; Federico M. Giorgi; Martin Bringmann; Bj(o)rn Usadel; Staffan Persson


    Transcriptional coordination, or co-expression, of genes may signify functional relatedness of the correspond-ing proteins. For example, several genes involved in secondary cell wall cellulose biosynthesis are co-expressed with genes engaged in the synthesis of xylan, which is a major component of the secondary cell wall. To extend these types of anal-yses, we investigated the co-expression relationships of all Carbohydrate-Active enZYmes (CAZy)-related genes for Arabidopsis thaliana. Thus, the intention was to transcriptionally link different cell wall-related processes to each other, and also to other biological functions. To facilitate easy manual inspection, we have displayed these interactions as networks and matrices, and created a web-based interface ( containing downloadable files for all the transcriptional associations.

  12. Fluorescent Probes for Exploring Plant Cell Wall Deconstruction: A Review

    Directory of Open Access Journals (Sweden)

    Gabriel Paës


    Full Text Available Plant biomass is a potential resource of chemicals, new materials and biofuels that could reduce our dependency on fossil carbon, thus decreasing the greenhouse effect. However, due to its chemical and structural complexity, plant biomass is recalcitrant to green biological transformation by enzymes, preventing the establishment of integrated bio-refineries. In order to gain more knowledge in the architecture of plant cell wall to facilitate their deconstruction, many fluorescent probes bearing various fluorophores have been devised and used successfully to reveal the changes in structural motifs during plant biomass deconstruction, and the molecular interactions between enzymes and plant cell wall polymers. Fluorescent probes are thus relevant tools to explore plant cell wall deconstruction.

  13. The role of the cell wall in fungal pathogenesis. (United States)

    Arana, David M; Prieto, Daniel; Román, Elvira; Nombela, César; Alonso-Monge, Rebeca; Pla, Jesús


    Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections.

  14. Type I vs type II spiral ganglion neurons exhibit differential survival and neuritogenesis during cochlear development

    Directory of Open Access Journals (Sweden)

    Housley Gary D


    Full Text Available Abstract Background The mechanisms that consolidate neural circuitry are a major focus of neuroscience. In the mammalian cochlea, the refinement of spiral ganglion neuron (SGN innervation to the inner hair cells (by type I SGNs and the outer hair cells (by type II SGNs is accompanied by a 25% loss of SGNs. Results We investigated the segregation of neuronal loss in the mouse cochlea using β-tubulin and peripherin antisera to immunolabel all SGNs and selectively type II SGNs, respectively, and discovered that it is the type II SGN population that is predominately lost within the first postnatal week. Developmental neuronal loss has been attributed to the decline in neurotrophin expression by the target hair cells during this period, so we next examined survival of SGN sub-populations using tissue culture of the mid apex-mid turn region of neonatal mouse cochleae. In organotypic culture for 48 hours from postnatal day 1, endogenous trophic support from the organ of Corti proved sufficient to maintain all type II SGNs; however, a large proportion of type I SGNs were lost. Culture of the spiral ganglion as an explant, with removal of the organ of Corti, led to loss of the majority of both SGN sub-types. Brain-derived neurotrophic factor (BDNF added as a supplement to the media rescued a significant proportion of the SGNs, particularly the type II SGNs, which also showed increased neuritogenesis. The known decline in BDNF production by the rodent sensory epithelium after birth is therefore a likely mediator of type II neuron apoptosis. Conclusion Our study thus indicates that BDNF supply from the organ of Corti supports consolidation of type II innervation in the neonatal mouse cochlea. In contrast, type I SGNs likely rely on additional sources for trophic support.

  15. Characters of Fractal Ultrastructure in Wood Cell Wall

    Institute of Scientific and Technical Information of China (English)

    LI Beimei; ZHAO Guangjie


    Fractal theory was introduced in order to describe the ultrastructure of wood cell wall in this paper.The cellulose chain clusters around nano-scale were viewed as a fractal object that consists of many fibrillar structural units with different scales including microfibrils.On the basis of the morphological data of wood cell wall.fractal dimensions of multi-level fibrillar structural units were calculated by fractal-geometry approach,and then the morphological and structural characteristics of fibers as well as the influences on wood properties were investigated according to the dimensions.Besides,the fractal self-nesting character of the ultrastruture was also analyzed.

  16. Hematopoietic Stem Cells Expansionin Rotating Wall Vessel

    Institute of Scientific and Technical Information of China (English)


    1 IntroductionClinical trials have demonstrated that ex vivo expanded hematopoietic stem cells (HSCs) and progenitors offer great promise in reconstituting in vivo hematopoiesis in patients who have undergone intensive chemotherapy. It is therefore necessary to develop a clinical-scale culture system to provide the expanded HSCs and progenitors. Static culture systems such as T-flasks and gas-permeable blood bags are the most widely used culture devices for expanding hematopoietic cells. But they reveal sev...

  17. Peripheral papillary tumor of type-II pneumocytes: a rare neoplasm of undetermined malignant potential. (United States)

    Dessy, E; Braidotti, P; Del Curto, B; Falleni, M; Coggi, G; Santa Cruz, G; Carai, A; Versace, R; Pietra, G G


    Peripheral papillary adenomas of the lung are uncommon neoplasms (only ten cases have been described so far in the English literature) composed predominantly of type-II pneumocytes and generally considered benign. We describe here two additional cases of this lung tumor. In both cases histological examination revealed an encapsulated papillary neoplasm with invasion of the capsule and, in one case, invasion of the adjacent alveoli and visceral pleura too. The proliferative index (Ki67) was less than 2% and the epithelial cells were positive for cytokeratins, surfactant apoproteins (SP), and nuclear thyroid transcription factor-1 (TTF- 1). Ultrastructurally, the epithelial cells showed the characteristic surface microvilli and cytoplasmic lamellar inclusions of type-II cells. Review of the literature has revealed two other cases of peripheral papillary adenoma of type-II pneumocytes with infiltrative features. Thus, we propose replacing the term peripheral papillary adenoma with peripheral papillary tumor of undetermined malignant potential.

  18. Type II superlattice technology for LWIR detectors (United States)

    Klipstein, P. C.; Avnon, E.; Azulai, D.; Benny, Y.; Fraenkel, R.; Glozman, A.; Hojman, E.; Klin, O.; Krasovitsky, L.; Langof, L.; Lukomsky, I.; Nitzani, M.; Shtrichman, I.; Rappaport, N.; Snapi, N.; Weiss, E.; Tuito, A.


    SCD has developed a range of advanced infrared detectors based on III-V semiconductor heterostructures grown on GaSb. The XBn/XBp family of barrier detectors enables diffusion limited dark currents, comparable with MCT Rule-07, and high quantum efficiencies. This work describes some of the technical challenges that were overcome, and the ultimate performance that was finally achieved, for SCD's new 15 μm pitch "Pelican-D LW" type II superlattice (T2SL) XBp array detector. This detector is the first of SCD's line of high performance two dimensional arrays working in the LWIR spectral range, and was designed with a ~9.3 micron cut-off wavelength and a format of 640 x 512 pixels. It contains InAs/GaSb and InAs/AlSb T2SLs, engineered using k • p modeling of the energy bands and photo-response. The wafers are grown by molecular beam epitaxy and are fabricated into Focal Plane Array (FPA) detectors using standard FPA processes, including wet and dry etching, indium bump hybridization, under-fill, and back-side polishing. The FPA has a quantum efficiency of nearly 50%, and operates at 77 K and F/2.7 with background limited performance. The pixel operability of the FPA is above 99% and it exhibits a stable residual non uniformity (RNU) of better than 0.04% of the dynamic range. The FPA uses a new digital read-out integrated circuit (ROIC), and the complete detector closely follows the interfaces of SCD's MWIR Pelican-D detector. The Pelican- D LW detector is now in the final stages of qualification and transfer to production, with first prototypes already integrated into new electro-optical systems.

  19. Human type II pneumocyte chemotactic responses to CXCR3 activation are mediated by splice variant A. (United States)

    Ji, Rong; Lee, Clement M; Gonzales, Linda W; Yang, Yi; Aksoy, Mark O; Wang, Ping; Brailoiu, Eugen; Dun, Nae; Hurford, Matthew T; Kelsen, Steven G


    Chemokine receptors control several fundamental cellular processes in both hematopoietic and structural cells, including directed cell movement, i.e., chemotaxis, cell differentiation, and proliferation. We have previously demonstrated that CXCR3, the chemokine receptor expressed by Th1/Tc1 inflammatory cells present in the lung, is also expressed by human airway epithelial cells. In airway epithelial cells, activation of CXCR3 induces airway epithelial cell movement and proliferation, processes that underlie lung repair. The present study examined the expression and function of CXCR3 in human alveolar type II pneumocytes, whose destruction causes emphysema. CXCR3 was present in human fetal and adult type II pneumocytes as assessed by immunocytochemistry, immunohistochemistry, and Western blotting. CXCR3-A and -B splice variant mRNA was present constitutively in cultured type II cells, but levels of CXCR3-B greatly exceeded CXCR3-A mRNA. In cultured type II cells, I-TAC, IP-10, and Mig induced chemotaxis. Overexpression of CXCR3-A in the A549 pneumocyte cell line produced robust chemotactic responses to I-TAC and IP-10. In contrast, I-TAC did not induce chemotactic responses in CXCR3-B and mock-transfected cells. Finally, I-TAC increased cytosolic Ca(2+) and activated the extracellular signal-regulated kinase, p38, and phosphatidylinositol 3-kinase (PI 3-kinase)/protein kinase B kinases only in CXCR3-A-transfected cells. These data indicate that the CXCR3 receptor is expressed by human type II pneumocytes, and the CXCR3-A splice variant mediates chemotactic responses possibly through Ca(2+) activation of both mitogen-activated protein kinase and PI 3-kinase signaling pathways. Expression of CXCR3 in alveolar epithelial cells may be important in pneumocyte repair from injury.

  20. Bacterial Cell Wall Growth, Shape and Division

    NARCIS (Netherlands)

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


    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 ou

  1. Cell wall modification in grapevine cells in response to UV stress investigated by atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lesniewska, E.; Adrian, M.; Klinguer, A.; Pugin, A


    Despite cell wall reinforcement being a well-known defence mechanism of plants, it remains poorly characterized from a physical point of view. The objective of this work was to further describe this mechanism. Vitis vinifera cv Gamay cells were treated with UV-light (254 nm), a well-known elicitor of defence mechanisms in grapevines, and physical cell wall modifications were observed using the atomic force microscopy (AFM) under native conditions. The grapevine cell suspensions were continuously observed in their culture medium from 30 min to 24 h after elicitation. In the beginning, cellulose fibrils covered by a matrix surrounded the control and treated cells. After 3 h, the elicited cells displayed sprouted expansions around the cell wall that correspond to pectin chains. These expansions were not observed on untreated grapevine cells. The AFM tip was used to determine the average surface elastic modulus of cell wall that account for cell wall mechanical properties. The elasticity is diminished in UV-treated cells. In a comparative study, grapevine cells showed the same decrease in cell wall elasticity when treated with a fungal biotic elicitor of defence response. These results demonstrate cell wall strengthening by UV stress.

  2. An emerging role of pectic rhamnogalacturonanII for cell wall integrity. (United States)

    Reboul, Rebecca; Tenhaken, Raimund


    The plant cell wall is a complex network of different polysaccharides and glycoproteins, showing high diversity in nature. The essential components, tethering cell wall are under debate, as novel mutants challenge established models. The mutant ugd2,3 with a reduced supply of the important wall precursor UDP-glucuronic acid reveals the critical role of the pectic compound rhamnogalacturonanII for cell wall stability. This polymer seems to be more important for cell wall integrity than the previously favored xyloglucan.

  3. Canine chondrocytes seeded in type I and type II collagen implants investigated in vitro. (United States)

    Nehrer, S; Breinan, H A; Ramappa, A; Shortkroff, S; Young, G; Minas, T; Sledge, C B; Yannas, I V; Spector, M


    Synthetic and natural absorbable polymers have been used as vehicles for implantation of cells into cartilage defects to promote regeneration of the articular joint surface. Implants should provide a pore structure that allows cell adhesion and growth, and not provoke inflammation or toxicity when implanted in vivo. The scaffold should be absorbable and the degradation should match the rate of tissue regeneration. To facilitate cartilage repair the chemical structure and pore architecture of the matrix should allow the seeded cells to maintain the chondrocytic phenotype, characterized by synthesis of cartilage-specific proteins. We investigated the behavior of canine chondrocytes in two spongelike matrices in vitro: a collagen-glycosaminoglycan (GAG) copolymer produced from bovine hide consisting of type I collagen and a porous scaffold made of type II collagen by extraction of porcine cartilage. Canine chondrocytes were seeded on both types of matrices and cultured for 3 h, 7 days, and 14 days. The histology of chondrocyte-seeded implants showed a significantly higher percentage of cells with spherical morphology, consistent with chondrocytic morphology, in the type II sponge at each time point. Pericellular matrix stained for proteoglycans and for type II collagen after 14 days. Biochemical analysis of the cell seeded sponges for GAG and DNA content showed increases with time. At day 14 there was a significantly higher amount of DNA and GAG in the type II matrix. This is the first study that directly compares the behavior of chondrocytes in type I and type II collagen matrices. The type II matrix may be of value as a vehicle for chondrocyte implantation on the basis of the higher percentage of chondrocytes retaining spherical morphology and greater biosynthetic activity that was reflected in the greater increase of GAG content.

  4. Cell wall structure and function in lactic acid bacteria. (United States)

    Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius


    The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts.

  5. Organization of the human keratin type II gene cluster at 12q13

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, S.J.; LeBlanc-Straceski, J.; Krauter, K. [Albert Einstein College of Medicine, Bronx, NY (United States)] [and others


    Keratin proteins constitute intermediate filaments and are the major differentiation products of mammalian epithelial cells. The epithelial keratins are classified into two groups, type I and type II, and one member of each group is expressed in a given epithelial cell differentiation stage. Mutations in type I and type II keratin genes have now been implicated in three different human genetic disorders, epidermolysis bullosa simplex, epidermolytic hyperkeratosis, and epidermolytic palmoplantar keratoderma. Members of the type I keratins are mapped to human chromosome 17, and the type II keratin genes are mapped to chromosome 12. To understand the organization of the type II keratin genes on chromosome 12, we isolated several yeast artificial chromosomes carrying these keratin genes and examined them in detail. We show that eight already known type II keratin genes are located in a cluster at 12q13, and their relative organization reflects their evolutionary relationship. We also determined that a type I keratin gene, KRT8, is located next to its partner, KRT18, in this cluster. Careful examination of the cluster also revealed that there may be a number of additional keratin genes at this locus that have not been described previously. 41 refs., 3 figs., 1 tab.

  6. In planta modification of the potato tuber cell wall

    NARCIS (Netherlands)

    Oomen, R.J.F.J.


    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 after

  7. Characterisation of cell wall polysaccharides in bilberries and black currants

    NARCIS (Netherlands)

    Hilz, H.


    During berry juice production, polysaccharides are released from the cell walls and cause thickening and high viscosity when the berries are mashed. Consequences are a low juice yield and a poor colour. This can be prevented by the use of enzymes that degrade these polysaccharides. To use these enzy

  8. Analyzing the complex machinery of cell wall biosynthesis

    NARCIS (Netherlands)

    Timmers, J.F.P.


    The plant cell wall polymers make up most of the plant biomass and provide the raw material for many economically important products including food, feed, bio-materials, chemicals, textiles, and biofuel. This broad range of functions and applications make the biosynthesis of these polysaccharides a

  9. Evidence for a Melanin Cell Wall Component in Pneumocystis carinii


    Icenhour, Crystal R.; Kottom, Theodore J.; Limper, Andrew H


    Fluorescein isothiocyanate-labeled monoclonal antibodies specific for fungal melanin were used in this study to visualize melanin-like components of the Pneumocystis carinii cell wall. A colorimetric enzyme assay confirmed these findings. This is the first report of melanin-like pigments in Pneumocystis.

  10. The role of the cell wall in plant immunity

    DEFF Research Database (Denmark)

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


    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...

  11. Aspergillus enzymes involved in degradation of plant cell wall polysaccharides

    NARCIS (Netherlands)

    Vries, de R.P.; Visser, J.


    Degradation of plant cell wall polysaccharides is of major importance in the food and feed, beverage, textile, and paper and pulp industries, as well as in several other industrial production processes. Enzymatic degradation of these polymers has received attention for many years and is becoming a m

  12. 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.


    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

  13. Polymer mobility in cell walls of cucumber hypocotyls (United States)

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


    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.

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

    DEFF Research Database (Denmark)

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


    . 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......, particularly when it comes to up-scaling of processes based on insoluble feed stocks....

  15. Roles of tRNA in cell wall biosynthesis

    DEFF Research Database (Denmark)

    Dare, Kiley; Ibba, Michael


    Recent research into various aspects of bacterial metabolism such as cell wall and antibiotic synthesis, degradation pathways, cellular stress, and amino acid biosynthesis has elucidated roles of aminoacyl-transfer ribonucleic acid (aa-tRNA) outside of translation. Although the two enzyme families...

  16. The digestion of yeast cell wall polysaccharides in veal calves

    NARCIS (Netherlands)

    Gaillard, B.D.E.; Weerden, van E.J.


    1. The digestibility of the cell wall polysaccharides of an alkane-grown yeast in different parts of the digestive tract of two veal calves fitted with re-entrant cannulas at the end of the ileum was studied by replacing part of the skim-milk powder of their ‘normal’, milk-substitute (all-milk-prote

  17. Critical role of the endogenous interferon ligand-receptors in type I and type II interferons response. (United States)

    Lasfar, Ahmed; Cook, Jeffry R; Cohen Solal, Karine A; Reuhl, Kenneth; Kotenko, Sergei V; Langer, Jerome A; Laskin, Debra L


    Separate ligand-receptor paradigms are commonly used for each type of interferon (IFN). However, accumulating evidence suggests that type I and type II IFNs may not be restricted to independent pathways. Using different cell types deficient in IFNAR1, IFNAR2, IFNGR1, IFNGR2 and IFN-γ, we evaluated the contribution of each element of the IFN system to the activity of type I and type II IFNs. We show that deficiency in IFNAR1 or IFNAR2 is associated with impairment of type II IFN activity. This impairment, presumably resulting from the disruption of the ligand-receptor complex, is obtained in all cell types tested. However, deficiency of IFNGR1, IFNGR2 or IFN-γ was associated with an impairment of type I IFN activity in spleen cells only, correlating with the constitutive expression of type II IFN (IFN-γ) observed on those cells. Therefore, in vitro the constitutive expression of both the receptors and the ligands of type I or type II IFN is critical for the enhancement of the IFN activity. Any IFN deficiency can totally or partially impair IFN activity, suggesting the importance of type I and type II IFN interactions. Taken together, our results suggest that type I and type II IFNs may regulate biological activities through distinct as well as common IFN receptor complexes.

  18. Action of xyloglucan hydrolase within the native cell wall architecture and its effect on cell wall extensibility in azuki bean epicotyls. (United States)

    Kaku, Tomomi; Tabuchi, Akira; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Hoson, Takayuki


    Xyloglucan hydrolase (XGH) has recently been purified from the cell wall of azuki bean (Vigna angularis Ohwi et Ohashi) epicotyls as a new type of xyloglucan-degrading enzyme [Tabuchi et al. (2001) Plant Cell Physiol. 42: 154]. In the present study, the effects of XGH on the mechanical properties of the cell wall and on the level and the molecular size of xyloglucans within the native wall architecture were examined in azuki bean epicotyls. When the epidermal tissue strips from the growing regions of azuki bean epicotyls were incubated with XGH, the mechanical extensibility of the cell wall dramatically increased. XGH exogenously applied to cell wall materials (homogenates) or epidermal tissue strips decreased the amount of xyloglucans via the solubilization of the polysaccharides. Also, XGH substantially decreased the molecular mass of xyloglucans in both materials. These results indicate that XGH is capable of hydrolyzing xyloglucans within the native cell wall architecture and thereby increasing the cell wall extensibility in azuki bean epicotyls.

  19. Waardenburg syndrome type II: phenotypic findings and diagnostic criteria. (United States)

    Liu, X Z; Newton, V E; Read, A P


    The Waardenburg syndrome (WS) consists of at least two distinct autosomal dominant hereditary disorders. WS Type I has been mapped to the distal part of chromosome 2q and the gene identified as PAX3. Other gene(s) are responsible for WS Type II. Mapping WS Type II requires accurate diagnosis within affected families. To establish diagnostic criteria for WS Type II, 81 individuals from 21 families with Type II WS were personally studied, and compared with 60 personally studied patients from 8 families with Type I and 253 cases of WS (Type I or II) from the literature. Sensorineural hearing loss (77%) and heterochromia iridum (47%) were the two most important diagnostic indicators for WS Type II. Both were more common in Type II than in Type I. Other clinical manifestations, such as white forelock and skin patches, were more frequent in Type I. We estimate the frequency of phenotypic traits and propose diagnostic criteria for WS Type II. In practice, a diagnosis of WS Type II can be made with confidence given a family history of congenital hearing loss and pigmentary disorders, where individuals have been accurately measured for ocular distances to exclude dystopia canthorum.

  20. Type II lepra reaction--an unusual presentation. (United States)

    Ray, Avas Chandra; Sen, Sumit; Banerjee, Sabyasachi; Mukhopadhyay, Jotideb


    Type II lepra reaction usually present with skin lesions. We report a 23 years old male patient presented with fever for two weeks with no visible skin lesion suggestive of leprosy and with no history of either completion or concurrent anti leprosy drug treatment was eventually turned out to be a case of Hansen's presenting with type II lepra reaction.

  1. Duality symmetries and the type II string effective action

    NARCIS (Netherlands)

    Bergshoeff, E.


    We discuss the duality symmetries of Type II string effective actions in nine, ten and eleven dimensions. As a by-product we give a covariant action underlying the ten-dimensional Type IIB supergravity theory. We apply duality symmetries to construct dyonic Type II string solutions in six dimensions

  2. Molecular deformation mechanisms of the wood cell wall material. (United States)

    Jin, Kai; Qin, Zhao; Buehler, Markus J


    Wood is a biological material with outstanding mechanical properties resulting from its hierarchical structure across different scales. Although earlier work has shown that the cellular structure of wood is a key factor that renders it excellent mechanical properties at light weight, the mechanical properties of the wood cell wall material itself still needs to be understood comprehensively. The wood cell wall material features a fiber reinforced composite structure, where cellulose fibrils act as stiff fibers, and hemicellulose and lignin molecules act as soft matrix. The angle between the fiber direction and the loading direction has been found to be the key factor controlling the mechanical properties. However, how the interactions between theses constitutive molecules contribute to the overall properties is still unclear, although the shearing between fibers has been proposed as a primary deformation mechanism. Here we report a molecular model of the wood cell wall material with atomistic resolution, used to assess the mechanical behavior under shear loading in order to understand the deformation mechanisms at the molecular level. The model includes an explicit description of cellulose crystals, hemicellulose, as well as lignin molecules arranged in a layered nanocomposite. The results obtained using this model show that the wood cell wall material under shear loading deforms in an elastic and then plastic manner. The plastic regime can be divided into two parts according to the different deformation mechanisms: yielding of the matrix and sliding of matrix along the cellulose surface. Our molecular dynamics study provides insights of the mechanical behavior of wood cell wall material at the molecular level, and paves a way for the multi-scale understanding of the mechanical properties of wood.


    Darvill, J E; McNeil, M; Darvill, A G; Albersheim, P


    The isolation, purification, and partial characterization of a glucuronoarabinoxylan, a previously unobserved component of the primary cell walls of dicotyledonous plants, are described. The glucuronoarabinoxylan constitutes approximately 5% of the primary walls of suspension-cultured sycamore cells. This glucuronoarabinoxylan possesses many of the structural characteristics of analogous polysaccharides that have been isolated from the primary and secondary cell walls of monocots as well as from the secondary cell walls of dicots. The glucuronoarabinoxylan of primary dicot cell walls has a linear beta-1,4-linked d-xylopyranosyl backbone with both neutral and acidic sidechains attached at intervals along its length. The acidic sidechains are terminated with glucuronosyl or 4-O-methyl glucuronosyl residues, whereas the neutral sidechains are composed of arabinosyl and/or xylosyl residues.

  4. Phenotypic screening of Arabidopsis T-DNA insertion lines for cell wall mechanical properties revealed ANTHOCYANINLESS2, a cell wall-related gene. (United States)

    Mabuchi, Atsushi; Soga, Kouichi; Wakabayashi, Kazuyuki; Hoson, Takayuki


    We performed a phenotypic screening of confirmed homozygous T-DNA insertion lines in Arabidopsis for cell wall extensibility, in an attempt to identify genes involved in the regulation of cell wall mechanical properties. Seedlings of each line were cultivated and the cell wall extensibility of their hypocotyls was measured with a tensile tester. Hypocotyls of lines with known cell wall-related genes showed higher or lower extensibility than those of the wild-type at high frequency, indicating that the protocol used was effective. In the first round of screening of randomly selected T-DNA insertion lines, we identified ANTHOCYANINLESS2 (ANL2), a gene involved in the regulation of cell wall mechanical properties. In the anl2 mutant, the cell wall extensibility of hypocotyls was significantly lower than that of the wild-type. Levels of cell wall polysaccharides per hypocotyl, particularly cellulose, increased in anl2. Microarray analysis showed that in anl2, expression levels of the major peroxidase genes also increased. Moreover, the activity of ionically wall-bound peroxidases clearly increased in anl2. The activation of peroxidases as well as the accumulation of cell wall polysaccharides may be involved in decreased cell wall extensibility. The approach employed in the present study could contribute to our understanding of the mechanisms underlying the regulation of cell wall mechanical properties.

  5. Studying biomolecule localization by engineering bacterial cell wall curvature.

    Directory of Open Access Journals (Sweden)

    Lars D Renner

    Full Text Available In this article we describe two techniques for exploring the relationship between bacterial cell shape and the intracellular organization of proteins. First, we created microchannels in a layer of agarose to reshape live bacterial cells and predictably control their mean cell wall curvature, and quantified the influence of curvature on the localization and distribution of proteins in vivo. Second, we used agarose microchambers to reshape bacteria whose cell wall had been chemically and enzymatically removed. By combining microstructures with different geometries and fluorescence microscopy, we determined the relationship between bacterial shape and the localization for two different membrane-associated proteins: i the cell-shape related protein MreB of Escherichia coli, which is positioned along the long axis of the rod-shaped cell; and ii the negative curvature-sensing cell division protein DivIVA of Bacillus subtilis, which is positioned primarily at cell division sites. Our studies of intracellular organization in live cells of E. coli and B. subtilis demonstrate that MreB is largely excluded from areas of high negative curvature, whereas DivIVA localizes preferentially to regions of high negative curvature. These studies highlight a unique approach for studying the relationship between cell shape and intracellular organization in intact, live bacteria.

  6. Increasing the efficacy of CD20 antibody therapy through the engineering of a new type II anti-CD20 antibody with enhanced direct and immune effector cell-mediated B-cell cytotoxicity

    NARCIS (Netherlands)

    Moessner, Ekkehard; Bruenker, Peter; Moser, Samuel; Puentener, Ursula; Schmidt, Carla; Herter, Sylvia; Grau, Roger; Gerdes, Christian; Nopora, Adam; van Puijenbroek, Erwin; Ferrara, Claudia; Sondermann, Peter; Jaeger, Christiane; Strein, Pamela; Fertig, Georg; Friess, Thomas; Schuell, Christine; Bauer, Sabine; Dal Porto, Joseph; Del Nagro, Christopher; Dabbagh, Karim; Dyer, Martin J. S.; Poppema, Sibrand; Klein, Christian; Umana, Pablo


    CD20 is an important target for the treatment of B-cell malignancies, including non-Hodgkin lymphoma as well as autoimmune disorders. B-cell depletion therapy using monoclonal antibodies against CD20, such as rituximab, has revolutionized the treatment of these disorders, greatly improving overall s

  7. Type II collagen is transiently expressed during avian cardiac valve morphogenesis. (United States)

    Swiderski, R E; Daniels, K J; Jensen, K L; Solursh, M


    We present new evidence of the temporal and spatial expression of type II collagen in the embryonic chick heart during the very early stages of its development. In particular, we emphasize the distribution of its mRNA and protein during valve formation. Type II collagen as well as several other fibrillar collagens (types I, III, and V) are present in stage 18 endocardial cushion mesenchymal cells. At stage 23, alpha 1 (II) collagen transcripts and the cognate polypeptide colocalize in the atrioventricular valves. As development proceeds, the relative abundance of alpha 1 (II) collagen transcripts decreases during the stages studied (stages 22 to 45; day 3.5 to day 19) as assayed by RNA blotting of extracts of whole hearts. Type II collagen protein was immunologically undetectable in stage 38 (day 12) hearts, although collagens I, III, and V persisted and localize in the valve regions, in the endothelial lining of the heart, and in the epicardium. In keeping with other observations of type II collagen expression in non-chondrogenic regions of a variety of vertebrate embryos, the avian heart also exhibits transient type II collagen expression.

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

    Directory of Open Access Journals (Sweden)

    Johannes eLiesche


    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.

  9. Resistance to antibiotics targeted to the bacterial cell wall. (United States)

    Nikolaidis, I; Favini-Stabile, S; Dessen, A


    Peptidoglycan is the main component of the bacterial cell wall. It is a complex, three-dimensional mesh that surrounds the entire cell and is composed of strands of alternating glycan units crosslinked by short peptides. Its biosynthetic machinery has been, for the past five decades, a preferred target for the discovery of antibacterials. Synthesis of the peptidoglycan occurs sequentially within three cellular compartments (cytoplasm, membrane, and periplasm), and inhibitors of proteins that catalyze each stage have been identified, although not all are applicable for clinical use. A number of these antimicrobials, however, have been rendered inactive by resistance mechanisms. The employment of structural biology techniques has been instrumental in the understanding of such processes, as well as the development of strategies to overcome them. This review provides an overview of resistance mechanisms developed toward antibiotics that target bacterial cell wall precursors and its biosynthetic machinery. Strategies toward the development of novel inhibitors that could overcome resistance are also discussed.

  10. Dislocation-mediated growth of bacterial cell walls

    CERN Document Server

    Amir, Ariel


    Recent experiments have illuminated a remarkable growth mechanism of rod-shaped bacteria: proteins associated with cell wall extension move at constant velocity in circles oriented approximately along the cell circumference (Garner et al., Science (2011), Dominguez-Escobar et al. Science (2011), van Teeffelen et al. PNAS (2011). We view these as dislocations in the partially ordered peptidoglycan structure, activated by glycan strand extension machinery, and study theoretically the dynamics of these interacting defects on the surface of a cylinder. Generation and motion of these interacting defects lead to surprising effects arising from the cylindrical geometry, with important implications for growth. We also discuss how long range elastic interactions and turgor pressure affect the dynamics of the fraction of actively moving dislocations in the bacterial cell wall.

  11. 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


    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

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

    NARCIS (Netherlands)

    Huang, J.H.


    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. Ho

  13. 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.


    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 pec

  14. Morphology of normal and degenerative nucleus pulposus cells and quantitative analysis of collagen type II protein%正常与退变髓核细胞形态学及Ⅱ型胶原蛋白的定量分析

    Institute of Scientific and Technical Information of China (English)

    王祺; 任龙韬; 卫成刚; 何君仁


    背景:椎间盘退变导致椎间隙狭窄的主要变化是髓核细胞表达软骨特异性基因产物蛋白聚糖和Ⅱ型胶原的减少。  目的:对成人的正常与退变椎间盘髓核细胞Ⅱ型胶原蛋白免疫荧光染色及番红O染色进行定量观察比较。  方法:取成人脊柱侧弯患者与椎间盘突出症患者自愿者术中取出的废弃髓核组织各3例,经培养后每个患者各测量26个细胞,正常组和退变组分别测量78个细胞。对正常与退变椎间盘髓核细胞进行番红“O”染色并行灰度及测定细胞内Ⅱ型胶原蛋白行免疫荧光染色定量测定。  结果与结论:免疫荧光染色显示:退变椎间盘髓核细胞仅轻度染色,染色模糊,其呈类圆形,纺锤形,梭形及不规则形,其内仅有极少量荧光颗粒;Ⅱ型胶原表达较正常髓核细胞降低显著(P0.05)。结果表明退变的椎间盘髓核细胞减少、部分凋亡,其细胞内Ⅱ型胶原蛋白含量较正常髓核细胞显著减少。%BACKGROUND:The narrowing of intervertebral space induced by the intervertebral disc degeneration is mainly characterized by the expression of proteoglycan in nucleus pulposus cells and the reduction of col agen type II. OBJECTIVE:To quantitatively observe col agen type II protein in adult normal and degenerative intervertebral disc nucleus pulposus cells by immunofluorescence staining and safranin O staining. METHODS:The nucleus pulposus specimens were col ected from adult scoliosis patients and patients with intervertebral disc protrusion, who were al volunteers. After culture, 26 cells in each patient were measured. There were 78 cells in both normal group and degeneration group. The normal and degenerative intervertebral disc nucleus pulposus cells were subjected to safranin“O”staining, and gray values were determined;intracellular col agen type II was detected by immunofluorescence staining. RESULTS AND CONCLUSION

  15. Ectopic lignification in primary cellulose-deficient cell walls of maize cell suspension cultures

    Institute of Scientific and Technical Information of China (English)

    Hugo Melida; Antonio Encina; Asier Largo-Gosens; Esther Novo-Uzal; Rogelio Santiago; Federico Pomar; Pedro Garca; Penelope Garca-Angulo; Jose Luis Acebes; Jesus Alvarez


    Maize (Zea mays L.) suspension-cultured cells with up to 70% less cellulose were obtained by stepwise habituation to dichlobenil (DCB), a cellulose biosynthesis inhibitor. Cellulose deficiency was accompanied by marked changes in cell wall matrix polysaccharides and phenolics as revealed by Fourier transform infrared (FTIR) spectroscopy. Cell wall compositional analysis indicated that the cellulose-deficient cell walls showed an enhancement of highly branched and cross-linked arabinoxylans, as well as an increased content in ferulic acid, diferulates and p-coumaric acid, and the presence of a polymer that stained positive for phloroglucinol. In accordance with this, cellulose-deficient cell walls showed a fivefold increase in Klason-type lignin. Thioacidolysis/GC-MS analysis of cellulose-deficient cell walls indicated the presence of a lignin-like polymer with a Syringyl/Guaiacyl ratio of 1.45, which differed from the sensu stricto stress-related lignin that arose in response to short-term DCB-treatments. Gene expression analysis of these cells indicated an overexpression of genes specific for the biosynthesis of monolignol units of lignin. A study of stress signaling pathways revealed an overexpression of some of the jasmonate signaling pathway genes, which might trigger ectopic lignification in response to cell wall integrity disruptions. In summary, the structural plasticity of primary cell walls is proven, since a lignification process is possible in response to cellulose impoverishment.

  16. Tomato Fruit Cell Wall Synthesis during Development and Senescence : In Vivo Radiolabeling of Wall Fractions Using [C]Sucrose. (United States)

    Mitcham, E J; Gross, K C; Ng, T J


    The pedicel of tomato fruit (Lycopersicon esculentum Mill., cv ;Rutgers') of different developmental stages from immature-green (IG) to red was injected on the vine with 7 microcuries [(14)C(U)]sucrose and harvested after 18 hours. Cell walls were isolated from outer pericarp and further fractionated yielding ionically associated pectin, covalently bound pectin, hemicellulosic fraction I, hemicellulosic fraction II, and cellulosic fraction II. The dry weight of the total cell wall and of each cell wall fraction per gram fresh weight of pericarp tissue decreased after the mature-green (MG) stage of development. Incorporation of radiolabeled sugars into each fraction decreased from the IG to MG3 (locules jellied but still green) stage. Incorporation in all fractions increased from MG3 to breaker and turning (T) and then decreased from T to red. Data indicate that cell wall synthesis continues throughout ripening and increases transiently from MG4 (locules jellied and yellow to pink in color) to T, corresponding to the peak in respiration and ethylene synthesis during the climacteric. Synthesis continued at a time when total cell wall fraction dry weight decreased indicating the occurrence of cell wall turnover. Synthesis and insertion of a modified polymer with removal of other polymers may produce a less rigid cell wall and allow softening of the tissue integrity during ripening.

  17. Analysis of the soluble cell wall proteome of gymnosperms. (United States)

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


    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.

  18. Orbital wall infarction in child with sickle cell disease. (United States)

    Janssens, C; Claeys, L; Maes, P; Boiy, T; Wojciechowski, M


    We present the case of a 17-year-old boy, known with homozygous sickle cell disease, who was admitted because of generalised pain. He developed bilateral periorbital oedema and proptosis, without pain or visual disturbances. In addition to hyperhydration, oxygen and analgesia IV antibiotics were started, to cover a possible osteomyelitis. Patients with sickle cell disease are at risk for vaso-occlusive crises, when the abnormally shaped red blood cells aggregate and block the capillaries. Such a crisis typically presents at a location with high bone marrow activity, as the vertebrae and long bones. At an early age, the bone marrow is still active at other sites, for example the orbital wall, and thus infarction can also occur there. Thus, in young persons with sickle cell disease, it is important to consider orbital wall infarction in the differential diagnosis, since the approach is different from osteomyelitis. If the disease is complicated by an orbital compression syndrome, corticosteroids or surgical intervention may be necessary to preserve the vision. In our patient, an MRI of the orbitae demonstrated periorbital oedema with bone anomalies in the orbital and frontal bones, confirming orbital wall infarction. Ophthalmological examination revealed no signs of pressure on the nervus opticus. The patient recovered gradually with conservative treatment.

  19. 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


    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...

  20. Impaired recycling of surfactant-like liposomes in type II pneumocytes from injured lungs


    Muller, B.; Garn, H; Hochscheid, R


    Methods: Different stages of lung injury were induced by exposing rats to 10 ppm nitrogen dioxide (NO2) for 3, 20, and 28 days. Type II cells were isolated from these lungs and recycling of 3H-DPPC labelled surfactant-like liposomes was studied in vitro.

  1. Matric variate Pearson type II-Riesz distribution

    Directory of Open Access Journals (Sweden)

    José A. Díaz-García


    Full Text Available The Pearson type II distribution is well known and is used in the general framework of real normed division algebras and Riesz distribution theory. Also, the so called Pearson type II-Riesz distribution, based on the Kotz–Riesz distribution, is presented in a unified way valid in the context of real, complex, quaternion and octonion random matrices. Specifically, the central nonsingular matric variate generalised Pearson type II-Riesz distribution and beta-Riesz type I distributions are derived in the addressed multiple numerical field settings.

  2. Dentinogenesis imperfecta type II: an affected family saga. (United States)

    Kamboj, Mala; Chandra, Anil


    Dentinogenesis imperfecta (DI) type II or hereditary opalescent dentin is inherited in simple autosomal dominant mode with high penetrance and low mutation rate. It generally affects both the deciduous and permanent dentitions. DI type II corresponds to a localized form of mesodermal dysplasia, observed in histodifferentiation. Early diagnosis and treatment are therefore, fundamental, aiming at obtaining a favourable prognosis since late intervention makes treatment more complex. We present two cases of DI type II with the disease affecting three generations of a family in India, and briefly highlight the molecular basis of this disease.

  3. Cytoplasmic streaming in plant cells: the role of wall slip. (United States)

    Wolff, K; Marenduzzo, D; Cates, M E


    We present a computer simulation study, via lattice Boltzmann simulations, of a microscopic model for cytoplasmic streaming in algal cells such as those of Chara corallina. We modelled myosin motors tracking along actin lanes as spheres undergoing directed motion along fixed lines. The sphere dimension takes into account the fact that motors drag vesicles or other organelles, and, unlike previous work, we model the boundary close to which the motors move as walls with a finite slip layer. By using realistic parameter values for actin lane and myosin density, as well as for endoplasmic and vacuole viscosity and the slip layer close to the wall, we find that this simplified view, which does not rely on any coupling between motors, cytoplasm and vacuole other than that provided by viscous Stokes flow, is enough to account for the observed magnitude of streaming velocities in intracellular fluid in living plant cells.

  4. Cell wall bound anionic peroxidases from asparagus byproducts. (United States)

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


    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.

  5. Plant cell walls: New insights from ancient species

    DEFF Research Database (Denmark)

    Sørensen, Iben; Willats, William George Tycho


    Cell walls are a defining feature of plants and have numerous crucial roles in growth and development. They are also the largest source of terrestrial biomass and have many important industrial applications - ranging from bulk products to functional food ingredients. There is considerable interest......¿4)-linked ß-D-Glcp are joined by occasional (1¿3)-linkages. This mixed linkage glucan (MLG) has been the subject of extensive research because of the economic importance of several Poales species including rice, barley and wheat and because MLG has proven health benefits. The recent discovery of MLG......-D-glucan is not unique to the Poales and is an abundant component of Equisetum arvense cell walls. Plant J 2008; 54:510-21....

  6. Life behind cell walls: paradigm lost, paradigm regained. (United States)

    Lamport, D T


    This review of the living cell wall and its protein components is in two parts. The first is anecdotal. A personal account spanning over 40 years research may perhaps be an antidote to one stereotypical view of scientists as detached and humorless. The second part deals with the meaning of function, particularly as it applies to hydroxyproline-rich glycoproteins. Function is a difficult word to define objectively. However, with help from such luminaries as Humpty Dumpty: "A word means what I want it to mean, neither more nor less," and Wittgenstein: "Giving examples of usage ... is the only way to talk about meaning," it is possible to construct a ziggurat representing increasingly complex levels of organization from molecular structure to ecology. Forty years ago I suggested that hydroxyproline-rich structural proteins played a key role in cell wall functioning. But because the bulk of the wall is carbohydrate, there has been an understandable resistance to paradigm change. Expansins, paradoxically, contribute greatly to this resistance because their modus operandi as cell-wall-loosening proteins is based on the idea that they break hydrogen bonds between polysaccharide chains allowing slippage. However, this view is not consistent with the recent discovery [Grobe et al. (1999) Eur. J. Biochem 263: 33-40] that beta-expansins may be proteases, as it implies that the extensin network is not a straightjacket but a substrate for expansin in muro. Such a direct role for extensins in both negative and positive regulation of cell expansion and elongation may constitute a major morphogenetic mechanism operating at all levels of plant growth and development.

  7. 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)


    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.

  8. Genetics Home Reference: glutaric acidemia type II (United States)

    ... feeding and decreased activity, and vomiting. These metabolic crises, which can be life-threatening, may be triggered ... normally active in the mitochondria , which are the energy-producing centers of cells. These enzymes help break ...

  9. Cell wall proteins in seedling cotyledons of Prosopis chilensis. (United States)

    Rodríguez, J G; Cardemil, L


    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.

  10. Progress Towards the Tomato Fruit Cell Wall Proteome

    Directory of Open Access Journals (Sweden)

    Eliel eRuiz May


    Full Text Available The plant cell wall (CW compartment, or apoplast, is host to a highly dynamic proteome, comprising large numbers of both enzymatic and structural proteins. This reflects its importance as the interface between adjacent cells and the external environment, the presence of numerous extracellular metabolic and signaling pathways, and the complex nature of wall structural assembly and remodeling during cell growth and differentiation. Tomato fruit ontogeny, with its distinct phases of rapid growth and ripening, provides a valuable experimental model system for CW proteomic studies, in that it involves substantial wall assembly, remodeling and coordinated disassembly. Moreover, diverse populations of secreted proteins must be deployed to resist microbial infection and protect against abiotic stresses. Tomato fruits also provide substantial amounts of biological material, which is a significant advantage for many types of biochemical analyses, and facilitates the detection of lower abundance proteins. In this review we describe a variety of orthogonal techniques that have been applied to identify CW localized proteins from tomato fruit, including approaches that: target the proteome of the CW and the overlying cuticle; functional ‘secretome’ screens; lectin affinity chromatography; and computational analyses to predict proteins that enter the secretory pathway. Each has its merits and limitations, but collectively they are providing important insights into CW proteome composition and dynamics, as well as some potentially controversial issues, such as the prevalence of non-canonical protein secretion.

  11. Adsorption of polycyclic aromatic hydrocarbons (PAHs) on Rhizopus oryzae cell walls: application of cosolvent models for validating the cell wall-water partition coefficient. (United States)

    Ma, Bin; Xu, Minmin; Wang, Jiaojiao; Chen, Huaihai; He, Yan; Wu, Laosheng; Wang, Haizhen; Xu, Jianming


    The cell wall-cosolvent partition coefficients (Km) of polycyclic aromatic hydrocarbons (PAHs) were determined for Rhizopus oryzae cell walls by controlling the volume fraction of methanol (f) ranging from 0.1 to 0.5. Five cosolvent models were employed for extrapolating the cell wall-water partition coefficients (Kw) in pure water. The extrapolated Kw values of four PAHs on R. oryzae cell walls were ranged from 2.9 to 5.1. Comparison of various Kw values of pyrene generated from extrapolation and the QSPR model, together with predicted different (PD), mean percentage deviations (MPD), and root mean square errors (RSE), revealed that the performance of the LL and Bayesian models were the best among all five tested cosolvent models. This study suggests that R. oryzae cell walls play an important role in the partitioning of PAHs during bioremediation because of the high Kw of fungal cell walls.

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

    DEFF Research Database (Denmark)

    Lin, Fan; Manisseri, Chithra; Fagerström, Alexandra


    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 compone...

  13. Plectasin, a Fungal Defensin, Targets the Bacterial Cell Wall Precursor Lipid II

    DEFF Research Database (Denmark)

    Schneider, Tanja; Kruse, Thomas; Wimmer, Reinhard


    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...

  14. Plasmonic Enhanced Type-II Superlattice Focal Plane Arrays Project (United States)

    National Aeronautics and Space Administration — SVT Associates proposes an novel type II superlattice structure to extend the cutoff wavelength and CBIRD SL photo diode structure with unipolar barriers to suppress...

  15. Effect of Wall Charge on Striation in Plasma Display Cells

    Institute of Scientific and Technical Information of China (English)

    HE Feng; OUYANG Jiting; CAO Jing; FENG Shuo; MIAO Jinsong; WANG Jianqi


    Different configurations and driving voltages have been employed to investigate the effect of the wall charge on the striations in macroscopic plasma display panel (PDP) cells.The experimental results show that a discharge channel near the dielectric layer is indispensable to striation occurring in the anode area during a discharge,while the pre-accumulated charge on the dielectric layer and the surface state are not important.The origin of the striation is related only to the physical process in the cell.The dielectric layer acts as a charge collector during a PDP discharge.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  17. Evidence for 'silicon' within the cell walls of suspension-cultured rice cells. (United States)

    He, Congwu; Wang, Lijun; Liu, Jian; Liu, Xin; Li, Xiuli; Ma, Jie; Lin, Yongjun; Xu, Fangsen


    Despite the ubiquity and beneficial role of silicon (Si) in plant biology, structural and chemical mechanisms operating at the single-cell level have not been extensively studied. To obtain insights regarding the effect of Si on individual cells, we cultivated suspended rice (Oryza sativa) cells in the absence and presence of Si and analyzed single cells using a combination of physical techniques including atomic force microscopy (AFM). Si is naturally present as a constituent of the cell walls, where it is firmly bound to the cell wall matrix rather than occurring within intra- or extracellular silica deposition, as determined by using inductively coupled plasma mass spectrometry (ICP-MS) and X-ray photoelectron spectroscopy (XPS). This species of Si, linked with the cell wall matrix, improves the structural stability of cell walls during their expansion and subsequent cell division. Maintaining cell shape is thereby enhanced, which may be crucial for the function and survival of cells. This study provides further evidence that organosilicon is present in plant cell walls, which broadens our understanding of the chemical nature of 'anomalous Si' in plant biology.

  18. Richner-Hanhart syndrome and tyrosinemia type II. (United States)

    Hunziker, N


    A patient already published a case of Richner-Hanhart syndrome (RHS) (stabilized corneal lesions and hyperkeratotic lesions on the palms and soles) proved to be associated with tyrosinemia type II. 2 other cases (sister and brother) with only typical dermatologic features of RHS and tyrosinemia type II are described. The treatment with a low phenylalanine and tyrosine diet improves the cutaneous lesions in our 3 cases.

  19. Generating controllable type-II Weyl points via periodic driving (United States)

    Bomantara, Raditya Weda; Gong, Jiangbin


    Type-II Weyl semimetals are a novel gapless topological phase of matter discovered recently in 2015. Similar to normal (type-I) Weyl semimetals, type-II Weyl semimetals consist of isolated band touching points. However, unlike type-I Weyl semimetals which have a linear energy dispersion around the band touching points forming a three-dimensional (3D) Dirac cone, type-II Weyl semimetals have a tilted conelike structure around the band touching points. This leads to various novel physical properties that are different from type-I Weyl semimetals. In order to study further the properties of type-II Weyl semimetals and perhaps realize them for future applications, generating controllable type-II Weyl semimetals is desirable. In this paper, we propose a way to generate a type-II Weyl semimetal via a generalized Harper model interacting with a harmonic driving field. When the field is treated classically, we find that only type-I Weyl points emerge. However, by treating the field quantum mechanically, some of these type-I Weyl points may turn into type-II Weyl points. Moreover, by tuning the coupling strength, it is possible to control the tilt of the Weyl points and the energy difference between two Weyl points, which makes it possible to generate a pair of mixed Weyl points of type-I and type-II. We also discuss how to physically distinguish these two types of Weyl points in the framework of our model via the Landau level structures in the presence of an artificial magnetic field. The results are of general interest to quantum optics as well as ongoing studies of Floquet topological phases.

  20. In situ analysis of cell wall polymers associated with phloem fibre cells in stems of hemp, Cannabis sativa L. (United States)

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


    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.

  1. Clear Cell Adenocarcinoma Arising from Abdominal Wall Endometriosis

    Directory of Open Access Journals (Sweden)

    Thouraya Achach


    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.

  2. Pressure Dependent Wall Relaxation in Polarized $^3$He Gaseous Cells

    CERN Document Server

    Peng, C; Chu, P -H; Gao, H; Zhang, Y


    Pressure dependence of longitudinal relaxation time (T$_1$) due to the cell wall was observed previously at both room temperature and low temperature in valved Rb-coated refillable $^3$He gaseous cells in \\cite{Zheng2}. The diffusion of $^3$He from measurement cell through a capillary tube to the valve and the subsequent depolarization on the surface of the valve was proposed to possibly explain such a pressure dependence at room temperature \\cite{Saam}. In this paper, we investigate this diffusion effect through measurements of T$_1$ with newly designed Rb-coated Pyrex glass cells at 295 K as well as finite element analysis (FEA) studies. Both the experimental results and FEA studies show that the diffusion effect is insufficient to explain the observed linear pressure-dependent behavior of T$_1$.

  3. Change in wall composition of transfer and aleurone cells during wheat grain development. (United States)

    Robert, P; Jamme, F; Barron, C; Bouchet, B; Saulnier, L; Dumas, P; Guillon, F


    In addition to the starchy endosperm, a specialized tissue accumulating storage material, the endosperm of wheat grain, comprises the aleurone layer and the transfer cells next to the crease. The transfer cells, located at the ventral region of the grain, are involved in nutrient transfer from the maternal tissues to the developing endosperm. Immunolabeling techniques, Raman spectroscopy, and synchrotron infrared micro-spectroscopy were used to study the chemistry of the transfer cell walls during wheat grain development. The kinetic depositions of the main cell wall polysaccharides of wheat grain endosperm, arabinoxylan, and (1-3)(1-4)-β-glucan in transfer cell walls were different from kinetics previously observed in the aleurone cell walls. While (1-3)(1-4)-β-glucan appeared first in the aleurone cell walls at 90°D, arabinoxylan predominated in the transfer cell walls from 90 to 445°D. Both aleurone and transfer cell walls were enriched in (1-3)(1-4)-β-glucan at the mature stage of wheat grain development. Arabinoxylan was more substituted in the transfer cell walls than in the aleurone walls. However, arabinoxylan was more feruloylated in the aleurone than in the transfer cell walls, whatever the stage of grain development. In the transfer cells, the ferulic acid was less abundant in the outer periclinal walls while para-coumarate was absent. Possible implications of such differences are discussed.

  4. Stimulation of elongation growth and cell wall loosening in rice coleoptiles under microgravity conditions in space. (United States)

    Hoson, Takayuki; Soga, Kouichi; Mori, Ryuji; Saiki, Mizue; Nakamura, Yukiko; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro


    We analyzed the growth rate and the cell wall properties of coleoptiles of rice seedlings grown at 23.6 degrees C for 68.5, 91.5 and 136 h during the Space Shuttle STS-95 mission. In space, elongation growth of coleoptiles was stimulated and the cell wall extensibility increased. Also, the levels of the cell wall polysaccharides per unit length of coleoptiles and the relative content of the high molecular mass matrix polysaccharides decreased in space. These differences in the cell wall polysaccharides could be involved in increasing the cell wall extensibility, leading to growth stimulation of rice coleoptiles in space.

  5. Principles of Bacterial Cell-Size Determination Revealed by Cell-Wall Synthesis Perturbations

    Directory of Open Access Journals (Sweden)

    Carolina Tropini


    Full Text Available Although bacterial cell morphology is tightly controlled, the principles of size regulation remain elusive. In Escherichia coli, perturbation of cell-wall synthesis often results in similar morphologies, making it difficult to deconvolve the complex genotype-phenotype relationships underlying morphogenesis. Here we modulated cell width through heterologous expression of sequences encoding the essential enzyme PBP2 and through sublethal treatments with drugs that inhibit PBP2 and the MreB cytoskeleton. We quantified the biochemical and biophysical properties of the cell wall across a wide range of cell sizes. We find that, although cell-wall chemical composition is unaltered, MreB dynamics, cell twisting, and cellular mechanics exhibit systematic large-scale changes consistent with altered chirality and a more isotropic cell wall. This multiscale analysis enabled identification of distinct roles for MreB and PBP2, despite having similar morphological effects when depleted. Altogether, our results highlight the robustness of cell-wall synthesis and physical principles dictating cell-size control.

  6. Measuring the Mechanical Properties of Plant Cell Walls

    Directory of Open Access Journals (Sweden)

    Hannes Vogler


    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.

  7. Genetic mapping of the dentinogenesis imperfecta type II locus

    Energy Technology Data Exchange (ETDEWEB)

    Crosby, A.H.; Dixon, M.J. [Univ. of Manchester (United Kingdom); Scherpbier-Heddema, T. [Fox Chase Cancer Center, Philadelphia, PA (United States)] [and others


    Dentinogenesis imperfecta type II (DGI-II) is an autosomal dominant disorder of dentin formation, which has previously been mapped to chromosome 4q12-21. In the current study, six novel short tandem-repeat polymorphisms (STRPs) have been isolated, five of which show significant evidence of linkage to DGI-II. To determine the order of the STRPs and define the genetic distance between them, nine loci (including polymorphisms for two known genes) were mapped through the CEPH reference pedigrees. The resulting genetic map encompasses 16.3 cM on the sex-averaged map. To combine this map with a physical map of the region, all of the STRPs were mapped through a somatic cell hybrid panel. The most likely location for the DGI-II locus within the fixed marker map is in the D4S2691-D4S2692 interval of 6.6 cM. The presence of a marker that shows no recombination with the DGI-II phenotype between the flanking markers provides an important anchor point for the creation of physical continuity across the DGI-II candidate region. 38 refs., 4 figs., 2 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Varner, J.E.


    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.

  9. Profiling the Hydrolysis of Isolated Grape Berry Skin Cell Walls by Purified Enzymes. (United States)

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


    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.

  10. Direct measurement of cell wall stress-stiffening and turgor pressure in live bacterial cells

    CERN Document Server

    Deng, Yi; Shaevitz, Joshua W


    The mechanical properties of gram-negative bacteria are governed by a rigid peptidoglycan (PG) cell wall and the turgor pressure generated by the large concentration of solutes in the cytoplasm. The elasticity of the PG has been measured in bulk and in isolated sacculi and shown to be compliant compared to the overall stiffness of the cell itself. However, the stiffness of the cell wall in live cells has not been measured. In particular, the effects that pressure-induced stress might have on the stiffness of the mesh-like PG network have not been addressed even though polymeric materials often exhibit large amounts of stress-stiffening. We study bulging Escherichia coli cells using atomic force microscopy to separate the contributions of the cell wall and turgor pressure to the overall cell stiffness. We find strong evidence of power-law stress-stiffening in the E. coli cell wall, with an exponent of $1.07 \\pm 0.25$, such that the wall is significantly stiffer in live cells ($E\\sim32\\pm10$ MPa) than in unpres...

  11. Downregulation of the UDP-arabinomutase gene in switchgrass (Panicum virgatum L. results in increased cell wall lignin while reducing arabinose-glycans

    Directory of Open Access Journals (Sweden)

    Jonathan Duran Willis


    Full Text Available Switchgrass (Panicum virgatum L. is a C4 perennial prairie grass and a lignocellulosic biofuels feedstock. Saccharification and biofuel yields are inhibited by the plant cell wall’s natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and crosslink other cell wall polymers. Grasses have predominately Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP linked to arabinofuranose (Araf. A family of UDP-arabinopyranose mutase/reversible glycosylated polypeptides (UAM/RGPs catalyze the interconversion between UDP-arabinopyranose (UDP-Arap and UDP-Araf. In switchgrass we knocked down expression of the endogenous PvUAM1 gene via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise morphologically similar to non-transgenics. There was decreased cell wall-associated arabinose in leaves and stems by over 50%, but there was an increase in cellulose in these organs. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control, but had increased glucose in cell walls. The increased glucose detected in stems and leaves indicates that attenuation of PvUAM1 expression might have downstream effects on starch

  12. Downregulation of a UDP-Arabinomutase Gene in Switchgrass (Panicum virgatum L.) Results in Increased Cell Wall Lignin While Reducing Arabinose-Glycans (United States)

    Willis, Jonathan D.; Smith, James A.; Mazarei, Mitra; Zhang, Ji-Yi; Turner, Geoffrey B.; Decker, Stephen R.; Sykes, Robert W.; Poovaiah, Charleson R.; Baxter, Holly L.; Mann, David G. J.; Davis, Mark F.; Udvardi, Michael K.; Peña, Maria J.; Backe, Jason; Bar-Peled, Maor; Stewart, C. N.


    Background: Switchgrass (Panicum virgatum L.) is a C4 perennial prairie grass and a dedicated feedstock for lignocellulosic biofuels. Saccharification and biofuel yields are inhibited by the plant cell wall’s natural recalcitrance against enzymatic degradation. Plant hemicellulose polysaccharides such as arabinoxylans structurally support and cross-link other cell wall polymers. Grasses predominately have Type II cell walls that are abundant in arabinoxylan, which comprise nearly 25% of aboveground biomass. A primary component of arabinoxylan synthesis is uridine diphosphate (UDP) linked to arabinofuranose (Araf). A family of UDP-arabinopyranose mutase (UAM)/reversible glycosylated polypeptides catalyze the interconversion between UDP-arabinopyranose (UDP-Arap) and UDP-Araf. Results: The expression of a switchgrass arabinoxylan biosynthesis pathway gene, PvUAM1, was decreased via RNAi to investigate its role in cell wall recalcitrance in the feedstock. PvUAM1 encodes a switchgrass homolog of UDP-arabinose mutase, which converts UDP-Arap to UDP-Araf. Southern blot analysis revealed each transgenic line contained between one to at least seven T-DNA insertions, resulting in some cases, a 95% reduction of native PvUAM1 transcript in stem internodes. Transgenic plants had increased pigmentation in vascular tissues at nodes, but were otherwise similar in morphology to the non-transgenic control. Cell wall-associated arabinose was decreased in leaves and stems by over 50%, but there was an increase in cellulose. In addition, there was a commensurate change in arabinose side chain extension. Cell wall lignin composition was altered with a concurrent increase in lignin content and transcript abundance of lignin biosynthetic genes in mature tillers. Enzymatic saccharification efficiency was unchanged in the transgenic plants relative to the control. Conclusion: Plants with attenuated PvUAM1 transcript had increased cellulose and lignin in cell walls. A decrease in cell

  13. Multi-Walled Carbon Nanotubes Inhibit Breast Cancer Cell Migration. (United States)

    Graham, Elizabeth G; Wailes, Elizabeth M; Levi-Polyachenko, Nicole H


    According to the American Cancer Society, breast cancer is the second leading cause of cancer death in the US. Cancerous cells may have inadequate adhesions to the extracellular matrix and adjacent cells. Previous work has suggested that restoring these contacts may negate the cancer phenotype. This work aims to restore those contacts using multi-walled carbon nanotubes (MWNTs). Varying concentrations of carboxylated MWNTs in water, with or without type I collagen, were dried to create a thin film upon which one of three breast cell lines were seeded: cancerous and metastatic MDA- MB-231 cells, cancerous but non-metastatic MCF7 cells, or non-cancerous MCF10A cells. Proliferation, adhesion, scratch and autophagy assays, western blots, and immunochemical staining were used to assess adhesion and E-cadherin expression. Breast cancer cells grown on a MWNT-collagen coated surface displayed increased adhesion and decreased migration which correlated with an increase in E-cadherin. This work suggests an alternative approach to cancer treatment by physically mediating the cells' microenvironment.

  14. Transient sedimentation in a cell with top and bottom walls (United States)

    Dance, Sarah; Maxey, Martin


    Wall boundary conditions may play a role in the screening of particle velocity fluctuations in Stokes suspensions. Using a Force-Coupling Method (Maxey and Patel, Int. J. Multiphase Flow 27 (2001)) we simulate transient sedimentation. The numerical scheme is a mixed Fourier-spectral element method, based on the Uzawa algorithm for Stokes flows. The sedimentation cell has top and bottom wall boundaries and periodic boundaries in the horizontal. These boundaries are chosen both for computational convenience, and to determine the relative importance of bottom and side walls in screening the velocity fluctuations. We consider several different box sizes, in an attempt to elucidate the connection between particle velocity fluctuation levels and box width. We quantify the evolution of particle mean velocities and fluctuations as well as the particle microstructure. In each case we observe an initial growth, followed by a decay in both the mean particle velocity and fluctuations. We also observe that a stable stratification develops. We suggest that the stratification is important in the evolution of the bulk mean velocity. We propose a mechanism involving particle cluster dynamics to explain the behaviour of the velocity fluctuations.

  15. Cellulose-hemicellulose interaction in wood secondary cell-wall (United States)

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


    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.

  16. Modification of chemical properties of cell walls by silicon and its role in regulation of the cell wall extensibility in oat leaves. (United States)

    Hossain, Mohammad Talim; Soga, Kouichi; Wakabayashi, Kazuyuki; Kamisaka, Seiichiro; Fujii, Shuhei; Yamamoto, Ryoichi; Hoson, Takayuki


    Effects of silicon on the mechanical and chemical properties of cell walls in the second leaf of oat (Avena sativa L.) seedlings were investigated. The cell wall extensibility in the basal region of the second leaf was considerably higher than that in the middle and subapical regions. Externally applied silicon increased the cell wall extensibility in the basal region, but it did not affect the extensibility in the middle and subapical regions. The amounts of cell wall polysaccharides and phenolic compounds, such as diferulic acid (DFA) and ferulic acid (FA), per unit length were lower in the basal region than in the middle and subapical regions of the leaf, and silicon altered these amounts in the basal region. In this region, silicon decreased the amounts of matrix polymers and cellulose per unit length and of DFA and FA, both per unit length and unit matrix polymer content. Silicon treatment also lowered the activity of phenylalanine ammonia-lyase (PAL, EC in the basal region. In contrast, the amount of silicon in cell walls increased in response to silicon treatment in three regions. These results suggest that in the basal region, silicon reduces the net wall mass and the formation of phenolic acid-mediated cross-linkages between wall polysaccharides. Such modifications of wall architecture may be responsible for the silicon-induced increase in the cell wall extensibility in oat leaves.

  17. A radioimmunoassay for lignin in plant cell walls

    Energy Technology Data Exchange (ETDEWEB)

    Dawley, R.M.


    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.

  18. Dentin phosphoprotein gene locus is not associated with dentinogenesis imperfecta types II and III

    Energy Technology Data Exchange (ETDEWEB)

    MacDougall, M.; Zeichner-David, M.; Davis, A.; Slavkin, H. (Univ. of Southern California, Los Angeles (United States)); Murray, J. (Univ. of Iowa, Iowa City (United States)); Crall, M. (Ohio State Univ., Columbus (United States))


    Dentinogenesis imperfecta (DGI) is an autosomal dominant inherited dental disease which affects dentin production and mineralization. Genetic linkage studies have been performed on several multigeneration informative kindreds. These studies determined linkage between DGI types II and III and group-specific component (vitamin D-binding protein). This gene locus has been localized to the long arm of human chromosome 4 in the region 4q11-q21. Although this disease has been mapped to chromosome 4, the defective gene product is yet to be determined. Biochemical studies have suggested abnormal levels of dentin phosphoprotein (DPP) associated with DGI type II. This highly acidic protein is the major noncollagenous component of dentin, being solely expressed by the ectomesenchymal derived odontoblast cells of the tooth. The purpose of the present study was to establish whether DPP is associated with DGI types II and III, by using molecular biology techniques. The results indicated that DPP is not localized to any region of human chromosome 4, thus suggesting that the DPP gene is not directly associated with DGI type II or DGI type III. The data do not exclude the possibility that other proteins associated with DPP posttranslational modifications might be responsible for this genetic disease.

  19. Chitosan Obtained from Cell Wall of Aspergillus Niger Mycelium

    Institute of Scientific and Technical Information of China (English)

    HUANG Hui-li; LIN Wen-luan; LIN Jian-ming


    Chitin from cell walls of Aspergillus Niger mycelium was prepared. A new method for the preparation of high deacetylation degree chitosan was studied in a dilute sodium hydroxide solution at a high pressure. The experimental results indicate that the deacetylation degree of the chitosan can reach 80% under the condition of a 5.00 mol/L sodium hydroxide solution at 0.1 MPa of pressure for 1 h. This method shows the advantages of the applications in the industry production and environment protection.

  20. Mass spectrometry for characterizing plant cell wall polysaccharides

    Directory of Open Access Journals (Sweden)

    Stefan eBauer


    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.

  1. Origin of wide-band IP type II bursts (United States)

    Pohjolainen, S.; Allawi, H.; Valtonen, E.


    Context. Different types of interplanetary (IP) type II bursts have been observed, where the more usual ones show narrow-band and patchy emissions, sometimes with harmonics, and which at intervals may disappear completely from the dynamic spectrum. The more unusual bursts are wide-band and diffuse, show no patches or breaks or harmonic emission, and often have long durations. Type II bursts are thought to be plasma emission, caused by propagating shock waves, but a synchrotron-emitting source has also been proposed as the origin for the wide-band type IIs. Aims: Our aim is to find out where the wide-band IP type II bursts originate and what is their connection to particle acceleration. Methods: We analyzed in detail 25 solar events that produced well-separated, wide-band IP type II bursts in 2001-2011. Their associations to flares, coronal mass ejections (CMEs), and solar energetic particle events (SEPs) were investigated. Results: Of the 25 bursts, 18 were estimated to have heights corresponding to the CME leading fronts, suggesting that they were created by bow shocks ahead of the CMEs. However, seven events were found in which the burst heights were significantly lower and which showed a different type of height-time evolution. Almost all the analyzed wide-band type II bursts were associated with very high-speed CMEs, originating from different parts of the solar hemisphere. In terms of SEP associations, many of the SEP events were weak, had poor connectivity due to the eastern limb source location, or were masked by previous events. Some of the events had precursors in specific energy ranges. These properties and conditions affected the intensity-time profiles and made the injection-time-based associations with the type II bursts difficult to interpret. In several cases where the SEP injection times could be determined, the radio dynamic spectra showed other features (in addition to the wide-band type II bursts) that could be signatures of shock fronts

  2. Acoustic Type-II Weyl Nodes from Stacking Dimerized Chains (United States)

    Yang, Zhaoju; Zhang, Baile


    Lorentz-violating type-II Weyl fermions, which were missed in Weyl's prediction of nowadays classified type-I Weyl fermions in quantum field theory, have recently been proposed in condensed matter systems. The semimetals hosting type-II Weyl fermions offer a rare platform for realizing many exotic physical phenomena that are different from type-I Weyl systems. Here we construct the acoustic version of a type-II Weyl Hamiltonian by stacking one-dimensional dimerized chains of acoustic resonators. This acoustic type-II Weyl system exhibits distinct features in a finite density of states and unique transport properties of Fermi-arc-like surface states. In a certain momentum space direction, the velocity of these surface states is determined by the tilting direction of the type-II Weyl nodes rather than the chirality dictated by the Chern number. Our study also provides an approach of constructing acoustic topological phases at different dimensions with the same building blocks.

  3. Binding of /sup 18/F by cell membranes and cell walls of Streptococcus mutans

    Energy Technology Data Exchange (ETDEWEB)

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


    The binding of /sup 18/F to isolated cell membranes and cell walls of Streptococcus mutans GS-5 or other bacteria was assayed. The attachment of /sup 18/F to these cell envelopes proceeded slowly and reached equilibrium within 60 min. /sup 18/F binding was stimulated by Ca/sup 2 +/ (1 mM). The binding of /sup 18/F to cellular components was dependent upon the pH, as well as the amount of /sup 18/F and dose of the binder employed. The binding of /sup 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 /sup 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 /sup 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 /sup 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 /sup 18/F per mg (dry weight). /sup 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 /sup 18/F binding by cell membranes and walls of oral flora.

  4. Properties of lead deposits in cell walls of radish (Raphanus sativus) roots. (United States)

    Inoue, Hiroshi; Fukuoka, Daisuke; Tatai, Yuri; Kamachi, Hiroyuki; Hayatsu, Manabu; Ono, Manami; Suzuki, Suechika


    Various mechanisms are involved in detoxification of heavy metals such as lead (Pb) in plant cells. Most of the Pb taken up by plants accumulates in their roots. However, the detailed properties of Pb complexes in roots remain unclear. We have investigated the properties of Pb deposits in root cell walls of radish (Raphanus sativus L.) seedlings grown on glass beads bed containing Pb pellets, which are the source of Pb-contamination in shooting range soils. Pb deposits were tightly bound to cell walls. Cell wall fragments containing about 50,000 ppm Pb were prepared from the roots. After extracting Pb from the cell wall fragments using HCl, Pb ions were recombined with the Pb-extracted cell wall fragments in a solution containing Pb acetate. When the cell wall fragments were treated with pectinase (E.C. and were chemically modified with 1-ethyl-3-dimethylamino-propylcarboimide, the Pb-rebinding ability of the treated cell wall fragments decreased. When acid-treated cell wall fragments were incubated in a solution containing Pb(2+) and excess amounts of a chelating agent, Pb recombined with the cell wall fragments were measured to estimate the affinity between Pb(2+) and the cell wall fragments. Our data show that Pb(2+) binds to carboxyl groups of cell walls. The source of the carboxyl groups is suggested to be pectic compounds. A stability constant of the Pb-cell wall complex was estimated to be about 10(8). The role of root cell walls in the mechanism underlying heavy metal tolerance was discussed.

  5. Realizing type-II Weyl points in an optical lattice (United States)

    Shastri, Kunal; Yang, Zhaoju; Zhang, Baile


    The recent discovery of the Lorentz symmetry-violating "type-II" Weyl semimetal phase has renewed interest in the study of Weyl physics in condensed-matter systems. However, tuning the exceptional properties of this novel state has remained a challenge. Optical lattices, created using standing laser beams, provide a convenient platform to tune tunneling parameters continuously in time. In this paper, we propose a generalized two level system exhibiting type-II Weyl points that can be realized using ultracold atoms in an optical lattice. The system is engineered using a three-dimensional lattice with complex π phase tunneling amplitudes. Various unique properties of the type-II Weyl semimetal such as open Fermi surface, anomalous chirality, and topological Fermi arcs can be probed using the proposed optical lattice scheme.

  6. Dental pulp response to bacterial cell wall material. (United States)

    Warfvinge, J; Dahlén, G; Bergenholtz, G


    Lipopolysaccharides (LPS) from Bacteroides oralis and Veillonella parvula and cell wall material from Lactobacillus casei were studied for their capacity to induce leukocyte migration in the dental pulp and in an implanted wound chamber. Three adult monkeys were challenged using lyophilized material sealed into buccal Class V cavities prepared in dentin. Pulp tissue responses were observed histologically eight and 72 hours after initiation of the experiment. Subjacent to cut dentinal tubules, bacterial materials induced polymorphonuclear leukocyte (PMN's) infiltration in the pulp tissue of the majority of test teeth examined. Responses were similar for the three bacterial test materials at both time periods. Topical applications of bovine serum albumin (BSA), used as a control, induced significantly less accumulation of PMN's. Assessments of induced exudate volumes and leukocyte densities in chambers implanted in rats showed comparable rankings with pulpal experiment between test (i.e., bacterial) and control (BSA) materials. Analysis of the data indicates that high-molecular-weight complexes of bacterial cell walls may adversely affect pulpal tissue across freshly exposed dentin.

  7. Chemical Profiling of the Plant Cell Wall through Raman Microspectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Han, Ju; Singh, Seema; Sun, Lan; Simmons, Blake; Auer, Manfred; Parvin, Bahram


    This paper presents a computational framework for chemical pro.ling of the plant cell wall through the Raman spectroscopy. The system enables query of known spectral signatures and clustering of spectral data based on intrinsic properties. As a result, presence and relative concentration of speci.c chemical bonds can be quanti.ed. The primary contribution of this paper is in representation of raman pro.le in terms of .uorescence background and multiscale peak detection at each grid point (voxel). Such a representation allows ef.cient spatial segmentation based on the coupling between high-level salient properties and low-level symbolic representation at each voxel. The high-level salient properties refer to preferred peaks and their attributes for the entire image. The low-level symbolic representations are based on .uorescence background, spectral peak locations, and their attributes. We present results on a corn stover tissue section that is imaged through Raman microscopy, and the results are consistent with the literature. In addition, automatic clustering indicates several distinct layers of the cell walls with different spectral signatures.

  8. 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


    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 a

  9. Plant Cell Wall Proteins: A Large Body of Data, but What about Runaways? (United States)

    Albenne, Cécile; Canut, Hervé; Hoffmann, Laurent; Jamet, Elisabeth


    Plant cell wall proteomics has been a very dynamic field of research for about fifteen years. A full range of strategies has been proposed to increase the number of identified proteins and to characterize their post-translational modifications. The protocols are still improving to enlarge the coverage of cell wall proteomes. Comparisons between these proteomes have been done based on various working strategies or different physiological stages. In this review, two points are highlighted. The first point is related to data analysis with an overview of the cell wall proteomes already described. A large body of data is now available with the description of cell wall proteomes of seventeen plant species. CWP contents exhibit particularities in relation to the major differences in cell wall composition and structure between these plants and between plant organs. The second point is related to methodology and concerns the present limitations of the coverage of cell wall proteomes. Because of the variety of cell wall structures and of the diversity of protein/polysaccharide and protein/protein interactions in cell walls, some CWPs can be missing either because they are washed out during the purification of cell walls or because they are covalently linked to cell wall components.

  10. Plant Cell Wall Proteins: A Large Body of Data, but What about Runaways?

    Directory of Open Access Journals (Sweden)

    Cécile Albenne


    Full Text Available Plant cell wall proteomics has been a very dynamic field of research for about fifteen years. A full range of strategies has been proposed to increase the number of identified proteins and to characterize their post-translational modifications. The protocols are still improving to enlarge the coverage of cell wall proteomes. Comparisons between these proteomes have been done based on various working strategies or different physiological stages. In this review, two points are highlighted. The first point is related to data analysis with an overview of the cell wall proteomes already described. A large body of data is now available with the description of cell wall proteomes of seventeen plant species. CWP contents exhibit particularities in relation to the major differences in cell wall composition and structure between these plants and between plant organs. The second point is related to methodology and concerns the present limitations of the coverage of cell wall proteomes. Because of the variety of cell wall structures and of the diversity of protein/polysaccharide and protein/protein interactions in cell walls, some CWPs can be missing either because they are washed out during the purification of cell walls or because they are covalently linked to cell wall components.

  11. Molecular Mechanisms for Vascular Development and Secondary Cell Wall Formation (United States)

    Yang, Jung Hyun; Wang, Huanzhong


    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 (SCWs) 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 SCW 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 SCW 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 SCW formation and discuss potential biotechnological uses. PMID:27047525

  12. MreB: pilot or passenger of cell wall synthesis? (United States)

    White, Courtney L; Gober, James W


    The discovery that the bacterial cell shape determinant MreB is related to actin spurred new insights into bacterial morphogenesis and development. The trafficking and mechanical roles of the eukaryotic cytoskeleton were hypothesized to have a functional ancestor in MreB based on evidence implicating MreB as an organizer of cell wall synthesis. Genetic, biochemical and cytological studies implicate MreB as a coordinator of a large multi-protein peptidoglycan (PG) synthesizing holoenzyme. Recent advances in microscopy and new biochemical evidence, however, suggest that MreB may function differently than previously envisioned. This review summarizes our evolving knowledge of MreB and attempts to refine the generalized model of the proteins organizing PG synthesis in bacteria. This is generally thought to be conserved among eubacteria and the majority of the discussion will focus on studies from a few well-studied model organisms.

  13. Cell wall proteins of Sporothrix schenckii as immunoprotective agents. (United States)

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


    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).

  14. Protective effect of niacinamide on interleukin-1beta-induced annulus fibrosus type II collagen degeneration in vitro. (United States)

    Duan, Deyu; Yang, Shuhua; Shao, Zengwu; Wang, Hong; Xiong, Xiaoqian


    The protective effect of niacinamide on interleukin-1beta (IL-1beta)-induced annulus fibrosus (AF) type II collagen degeneration in vitro and the mechanism were investigated. Chiba's intervertebral disc (IVD) culture models in rabbits were established and 48 IVDs from 12 adult Japanese white rabbits were randomly divided into 4 groups: normal control group, niacinamide-treated group, type II collagen degneration group (IL-1beta) and treatment group (niacinamide+IL-1beta). After culture for one week, AFs were collected for inducible nitric oxide synthase (iNOS), cysteine containing aspartate specific protease-3 (Caspase-3) and type II collagen immunohistochemical examination, and type II collagen reverse transcription polymerase chain reaction (RT-PCR). The results showed that rate of iNOS positive staining AF cells in the 4 groups was 17.6%, 10.9%, 73.9% and 19.3% respectively. The positive rate in treatment group was significantly lower than in the type II collagen degeneration group (Pniacinamide could effectively inhibit IL-1beta stimulated increase of iNOS and Caspase-3 in AF, and alleviate IL-1beta-caused destruction and synthesis inhibition of type II collagen. Niacinamide is of potential for clinical treatment of IVD degeneration.

  15. Soya beans and Maize : The effect of chemical and physical structure of cell wall polysaccharides on fermentation kinetics


    Laar, van de, P.


    The analysis of the relationship between cell wall composition and fermentation of endosperm cell walls of soya beans and maize was approached from three different angles. Firstly, the fermentation (rate and extent of fermentation, the sugar degradation pattern, and volatile fatty acid production) of soya bean and maize cell walls was analysed, both in situ and in vitro. This analysis revealed that the physical structure of the cell wall (particle size and cell wall thickness) influences cell...

  16. XIAP acts as a switch between type I and type II FAS-induced apoptosis signalling


    Jost, Philipp J; Grabow, Stephanie; Gray, Daniel; McKenzie, Mark D.; Nachbur, Ueli; Huang, David C. S.; Bouillet, Philippe; Thomas, Helen E.; Borner, Christoph; Silke, John; Strasser, Andreas; Kaufmann, Thomas


    FAS (APO-1/CD95) and its physiological ligand, FASL, regulate apoptotic death of unwanted or dangerous cells in many tissues, functioning as a guardian against autoimmunity and cancer development1-4. Distinct cell types differ in the mechanisms by which the ‘death receptor’ FAS triggers their apoptosis1-4. In type I cells, such as lymphocytes, activation of ‘effector caspases’ by FAS-induced activation of caspase-8 suffices for cell killing whereas in type II cells, including hepatocytes and ...

  17. Retinoid-induced differentiation of acute promyelocytic leukemia involves PML-RARalpha-mediated increase of type II transglutaminase. (United States)

    Benedetti, L; Grignani, F; Scicchitano, B M; Jetten, A M; Diverio, D; Lo Coco, F; Avvisati, G; Gambacorti-Passerini, C; Adamo, S; Levin, A A; Pelicci, P G; Nervi, C


    All-trans retinoic acid (t-RA) administration leads to complete remission in acute promyelocytic leukemia (APL) patients by inducing growth arrest and differentiation of the leukemic clone. In the present study, we show that t-RA treatment dramatically induced type II transglutaminase (type II TGase) expression in cells carrying the t(15;17) translocation and expressing the PML-RARalpha product such as the APL-derived NB4 cell line and fresh leukemic cells from APL patients. This induction correlated with t-RA-induced growth arrest, granulocytic differentiation, and upregulation of the leukocyte adherence receptor beta subunit (CD18) gene expression. The increase in type II TGase was not abolished by cycloheximide treatment, suggesting that synthesis of a protein intermediate was not required for the induction. t-RA did not significantly alter the rate of growth arrest and did not stimulate differentiation and type II TGase activity in NB4.306 cells, a t-RA-resistant subclone of the NB4 cell line, or in leukemic cells derived from two patients morphologically defined as APL but lacking the t(15;17). However, in NB4.306 cells, t-RA treatment was able to increase CD18 mRNA expression in a manner similar to NB4 cells. The molecular mechanisms involved in the induction of these genes were investigated. In NB4 cells, using novel receptor-selective ligands such as 9-cis-RA, TTNPB, AM580, and SR11217, we found that RAR- and RARalpha-selective retinoids were able to induce growth arrest, granulocytic differentiation, and type II TGase, whereas the RXR-selective retinoid SR11217 was inactive. Moreover, an RAR alpha-antagonist completely inhibited the expression of type II TGase and CD18 induced by these selective retinoids in NB4 cells. In NB4.306 cells, an RARalpha-dependent signaling pathway was found involved in the modulation of CD18 expression. In addition, expression of the PML-RARalpha gene in myeloid U937 precursor cells resulted in the ability of these cells to

  18. The connection of cytoskeletal network with plasma membrane and the cell wall

    Institute of Scientific and Technical Information of China (English)

    Zengyu Liu; Staffan Persson; Yi Zhang


    The cell wall provides external support of the plant cells, while the cytoskeletons including the microtubules and the actin filaments constitute an internal framework. The cytoskeletons contribute to the cell wall biosynthesis by spatially and temporarily regulating the transportation and deposition of cell wall components. This tight control is achieved by the dynamic behavior of the cytoskeletons, but also through the tethering of these structures to the plasma membrane. This tethering may also extend beyond the plasma membrane and impact on the cell wall, possibly in the form of a feedback loop. In this review, we discuss the linking components between the cytoskeletons and the plasma membrane, and/or the cell wall. We also discuss the prospective roles of these components in cell wall biosyn-thesis and modifications, and aim to provide a platform for further studies in this field.

  19. Hematopoietic Stem Cells Expansion in Rotating Wall Vessel

    Institute of Scientific and Technical Information of China (English)

    Yang LIU; Tian-Qing LIU; Xiu-Bo FAN; Dan GE; Zhan-Feng CUI; Xue-Hu MA


    @@ 1 Introduction Clinical trials have demonstrated that ex vivo expanded hematopoietic stem cells (HSCs) and progenitors offer great promise in reconstituting in vivo hematopoiesis in patients who have undergone intensive chemotherapy.It is therefore necessary to develop a clinical-scale culture system to provide the expanded HSCs and progenitors.Static culture systems such as T-flasks and gas-permeable blood bags are the most widely used culture devices for expanding hematopoietic cells. But they reveal several inherent limitations: ineffective mixing, lack of control options for dissolved oxygen and pH and difficulty in continuous feeding, which restricts the usefulness of static systems. Several advanced bioreactors have been used in the field of HSCs expansion. But hematopoietic cells are extremely sensitive to shear, so cells in bioreactors such as stirred and perfusion culture systems may suffer physical damage. This problem will be improved by applying the rotating wall vessel (RWV) bioreactor in clinic because of its low shear and unique structure. In this research, cord blood (CB) HSCs were expanded by means of a cell-dilution feeding protocol in RWV.

  20. Effects of Oral Administration of Type II Collagen on Rheumatoid Arthritis (United States)

    Trentham, David E.; Dynesius-Trentham, Roselynn A.; Orav, E. John; Combitchi, Daniel; Lorenzo, Carlos; Sewell, Kathryn Lea; Hafler, David A.; Weiner, Howard L.


    Rheumatoid arthritis is an inflammatory synovial disease thought to involve T cells reacting to an antigen within the joint. Type II collagen is the major protein in articular cartilage and is a potential autoantigen in this disease. Oral tolerization to autoantigens suppresses animal models of T cell-mediated autoimmune disease, including two models of rheumatoid arthritis. In this randomized, double-blind trial involving 60 patients with severe, active rheumatoid arthritis, a decrease in the number of swollen joints and tender joints occurred in subjects fed chicken type II collagen for 3 months but not in those that received a placebo. Four patients in the collagen group had complete remission of the disease. No side effects were evident. These data demonstrate clinical efficacy of an oral tolerization approach for rheumatoid arthritis.

  1. Role of the cell wall integrity and filamentous growth mitogen-activated protein kinase pathways in cell wall remodeling during filamentous growth. (United States)

    Birkaya, Barbara; Maddi, Abhiram; Joshi, Jyoti; Free, Stephen J; Cullen, Paul J


    Many fungal species including pathogens exhibit filamentous growth (FG) as a means of foraging for nutrients. Genetic screens were performed to identify genes required for FG in the budding yeast Saccharomyces cerevisiae. Genes encoding proteins with established functions in transcriptional activation (MCM1, MATalpha2, PHD1, MSN2, SIR4, and HMS2), cell wall integrity (MPT5, WSC2, and MID2), and cell polarity (BUD5) were identified as potential regulators of FG. The transcription factors MCM1 and MATalpha2 induced invasive growth by promoting diploid-specific bipolar budding in haploid cells. Components of the cell wall integrity pathway including the cell surface proteins Slg1p/Wsc1p, Wsc2p, Mid2p, and the mitogen-activated protein kinase (MAPK) Slt2p/Mpk1p contributed to multiple aspects of the FG response including cell elongation, cell-cell adherence, and agar invasion. Mid2p and Wsc2p stimulated the FG MAPK pathway through the signaling mucin Msb2p and components of the MAPK cascade. The FG pathway contributed to cell wall integrity in parallel with the cell wall integrity pathway and in opposition with the high osmolarity glycerol response pathway. Mass spectrometry approaches identified components of the filamentous cell wall including the mucin-like proteins Msb2p, Flo11p, and subtelomeric (silenced) mucin Flo10p. Secretion of Msb2p, which occurs as part of the maturation of the protein, was inhibited by the ss-1,3-glucan layer of the cell wall, which highlights a new regulatory aspect to cell wall remodeling in this organism. Disruption of ss-1,3-glucan linkages induced mucin shedding and resulted in defects in cell-cell adhesion and invasion of cells into the agar matrix.

  2. 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


    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...... have focused primarily upon late divergent multicellular land plants and specialized cell types (e.g., pollen tubes, root hairs). Here, we describe a unicellular green alga, Penium margaritaceum (Penium), which can serve as a valuable model organism for understanding cell expansion and the underlying...

  3. Enzymatic Breakdown of Type II Collagen in the Human Vitreous

    NARCIS (Netherlands)

    van Deemter, Marielle; Pas, Hendri H.; Kuijer, Roel; van der Worp, Roelofje J.; Hooymans, Johanna M. M.; Los, Leonoor I.


    PURPOSE. To investigate whether enzymatic collagen breakdown is an active process in the human vitreous. METHODS. Human donor eyes were used for immunohistochemistry to detect the possible presence of the matrix metalloproteinase (MMP)-induced type II collagen breakdown product col2-3/4C-short in th

  4. Carbon and Silicate Dust Condensation in Type II Supernovae (United States)

    Deneault, Ethan A.-N.; Morales, B.


    We investigate the chemistry of formation and destruction processes of molecules in the expanding and cooling ejecta of Type II Supernovae. In this work, we use a kinetic chemistry network to explore the parameters and conditions of the ejecta which are required for the condensation of graphite and silicon carbide grains.

  5. Knowledge Is Power: Teaching Children about Type II Diabetes (United States)

    Feild-Berner, Natalie; Balgopal, Meena


    World Diabetes Day (November 14) offers a wonderful opportunity to educate elementary children about the power they have to control their health. First lady Michelle Obama has urged Americans to educate themselves about childhood obesity, which is often associated with the onset of type II diabetes (Rabin 2010). The authors developed activities to…


    Directory of Open Access Journals (Sweden)

    M. C. Bersten


    Full Text Available We present progress in light curve models of type II-P supernovae (SNe II-P obtained using a newly devel- oped, one-dimensional hydrodynamic code. Using simple initial models (polytropes, we reproduced the global behavior of the observed light curves and we analyzed the sensitivity of the light curves to the variation of free parameters.

  7. Type II (noninsulin-dependent) diabetes: new treatment options. (United States)

    Bodzin, B J


    Type II diabetes (noninsulin-dependent diabetes mellitus [NIDDM]) is a common primary and secondary diagnosis in home care patients. This article describes the pathophysiology of NIDDM, the new drugs that have been released for treatment, and the nursing implications inherent in using these new medications.

  8. Type II Shocks Characteristics: Comparison with associated CMEs and Flares

    CERN Document Server

    Pothitakis, G; Preka-Papadema, P; Moussas, X; Caroubalos, C; Alissandrakis, C E; Hillaris, A; Tsitsipis, P; Kontogeorgos, A; Bougeret, J -L; Dumas, G; 10.1063/1.2347985


    A number of metric (100-650 MHz) typeII bursts was recorded by the ARTEMIS-IV radiospectrograph in the 1998-2000 period; the sample includes both CME driven shocks and shocks originating from flare blasts. We study their characteristics in comparison with characteristics of associated CMEs and flares.

  9. A Type II Radio Burst without a Coronal Mass Ejection

    CERN Document Server

    Su, W; Ding, M D; Chen, P F; Sun, J Q


    Type II radio bursts are thought to be a signature of coronal shocks. In this paper, we analyze a short-lived type II burst that started at 07:40 UT on 2011 February 28. By carefully checking white-light images, we find that the type II radio burst is not accompanied by a coronal mass ejection, only with a C2.4 class flare and narrow jet. However, in the extreme-ultraviolet (EUV) images provided by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO), we find a wave-like structure that propagated at a speed of $\\sim$ 600 km s$^{-1}$ during the burst. The relationship between the type II radio burst and the wave-like structure is in particular explored. For this purpose, we first derive the density distribution under the wave by the differential emission measure (DEM) method, which is used to restrict the empirical density model. We then use the restricted density model to invert the speed of the shock that produces the observed frequency drift rate in the dynamic spectrum. The ...

  10. Acute type II cryoglobulinaemic vasculitis mimicking atherosclerotic peripheral vascular disease.

    LENUS (Irish Health Repository)

    Saeed, A


    Atherosclerotic peripheral vascular disease is a common presenting cause for digital ischaemia in life long smokers. Acute severe Type II Cryoglobulinaemic vasculitis is a rare yet important cause, which may present with similar clinical features and which if undiagnosed may be rapidly fatal. Following the instigation of therapy with intravenous methylprednisolone and cyclophosphamide this patient made an excellent recovery.

  11. Type-II Supernovae and Neutrino Magnetic Moment

    CERN Document Server

    Nunokawa, H; Valle, José W F


    The present solar and atmospheric neutrino data together with the LSND results and the presence of hot dark matter (HDM) suggest the existence of a sterile neutrino at the eV scale. We have reanalysed the effect of resonant type-II supernova. We analyse the implications of $\

  12. Biceps instability and Slap type II tear in overhead athletes. (United States)

    Osti, Leonardo; Soldati, Francesco; Cheli, Andrea; Pari, Carlotta; Massari, Leo; Maffulli, Nicola


    Type II lesions are common lesions encountered in overhead athletes with controversies arising in term of timing for treatment, surgical approach, rehabilitation and functional results. The aim of our study was to evaluate the outcomes of arthroscopic repair of type II SLAP tears in overhead athletes, focusing on the time elapsed from diagnosis and treatment, time needed to return to sport, rate of return to sport and to previous level of performance, providing an overview concerning evidence for the effectiveness of different surgical approaches to type II SLAP tears in overhead athletes. A internet search on peer reviewed Journal from 1990, first descriprion of this pathology, to 2012, have been conducted evaluating the outcomes for both isolated Slap II tear overhead athletes and those who presented associated lesions treated. The results have been analyzed according to the scale reported focusing on return to sport and level of activity. Apart from a single study, non prospective level I and II studies were detected. Return to play at the same level ranged form 22% to 94% with different range of technique utilized with the majority of the authors recommending the fixation of these lesions but biceps tenodesis can lead to higher satisfaction racte when directly compated to the anchor fixation. Associated pathologies such as partial or full tickness rotator cuff tear did not clearly affect the outcomes and complications rate. There is no consensus regarding timing and treatment for type II SLAP, especially in overhead athletes who need to regain a high level of performance.

  13. Area Expansivity Moduli of Regenerating Plant Protoplast Cell Walls Exposed to Shear Flows (United States)

    Fujimura, Yuu; Iino, Masaaki; Watanabe, Ugai


    To control the elasticity of the plant cell wall, protoplasts isolated from cultured Catharanthus roseus cells were regenerated in shear flows of 115 s-1 (high shear) and 19.2 s-1 (low shear, as a control). The surface area expansivity modulus and the surface breaking strength of these regenerating protoplasts were measured by a micropipette aspiration technique. Cell wall synthesis was also measured using a cell wall-specific fluorescent dye. High shear exposure for 3 h doubled both the surface area modulus and breaking strength observed under low shear, significantly decreased cell wall synthesis, and roughly quadrupled the moduli of the cell wall. Based on the cell wall synthesis data, we estimated the three-dimensional modulus of the cell wall to be 4.1± 1.2 GPa for the high shear, and 0.35± 0.2 GPa for the low shear condition, using the surface area expansivity modulus divided by the cell wall thickness, which is identical with the Young’s modulus divided by 2(1-σ), where σ is Poisson's ratio. We concluded that high shear exposure considerably strengthens the newly synthesized cell wall.

  14. Differential Inhibition of the TGF-β Signaling Pathway in HCC Cells Using the Small Molecule Inhibitor LY2157299 and the D10 Monoclonal Antibody against TGF-β Receptor Type II.

    Directory of Open Access Journals (Sweden)

    Francesco Dituri

    Full Text Available We investigated blocking the TGF-β signaling pathway in HCC using two small molecule inhibitors (LY2157299, LY2109761 and a neutralizing humanized antibody (D10 against TGF-βRII. LY2157299 and LY2109761 inhibited HCC cell migration on Laminin-5, Fibronectin, Vitronectin, Fibrinogen and Collagen-I and de novo phosphorylation of pSMAD2. LY2157299 inhibited HCC migration and cell growth independently of the expression levels of TGF-βRII. In contrast to LY2157299, D10 showed a reduction in pSMAD2 only after a short exposure. This study supports the use of LY2157299 in clinical trials, and presents new insights into TGF-β receptor cycling in cancer cells.

  15. A universal characteristic of type II radio bursts (United States)

    Aguilar-Rodriguez, E.; Gopalswamy, N.; MacDowall, R.; Yashiro, S.; Kaiser, M. L.


    We present a study on the spectral properties of interplanetary type II radio bursts observed by the Radio and Plasma Wave (WAVES) experiment on board the Wind spacecraft. We investigated the relative bandwidth of the type II radio bursts observed by WAVES from 1997 up to 2003. We obtained three sets of events, based on the frequency domain of occurrence: 109 events in the low-frequency domain (30 KHz to 1000 kHz, detected by the RAD1 receiver), 216 events in the high-frequency domain (1-14 MHz, observed by the RAD2 receiver), and 73 events that spanned both domains (RAD1 and RAD2). Statistical results show that the average bandwidth-to-frequency ratio (BFR) was 0.28 ± 0.15, 0.26 ± 0.16, and 0.32 ± 0.15 for RAD1, RAD2, and RAD1 + RAD2, respectively. We compared our results with those obtained for ISEE-3 type II bursts and found a difference in the average BFR, which seems to be due to a selection effect. The BFR of the WAVES type II bursts is similar to that of metric type II bursts reported in published works. This suggests that the BFR is a universal characteristic, irrespective of the spectral domain. Finally, we also studied the BFR evolution with heliocentric distance using white-light observation of the associated coronal mass ejections. We found that the BFR remains roughly constant in the SOHO/LASCO field of view (i.e., from 2.1 to 32 solar radii), while the bandwidth itself decreases.

  16. 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.


    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.

  17. Pectinous cell wall thickenings formation - A common defense strategy of plants to cope with Pb. (United States)

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


    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.

  18. A recombinant CHSE-214 cell line expressing an Mx1 promoter-reporter system responds to both interferon type I and type II from salmonids and represents a versatile tool to study the IFN-system in teleost fish. (United States)

    Jørgensen, Jorunn B; Johansen, Audny; Hegseth, Marit N; Zou, Jun; Robertsen, Børre; Collet, Bertrand; Secombes, Christopher J


    A transgenic cell line for the detection of salmon interferons (IFNs) has been established. It is based on a CHSE-214 cell line containing a reporter construct expressing firefly luciferase under the control of the rainbow trout promoter for the IFN-induced Mx1 gene. This cell line, named CHSE-Mx10, showed IFN-induced luciferase expression after more than 80 passages, confirming the stability of this cell line. Interestingly, the Mx promoter was shown to respond to both salmon IFN-alpha/beta and trout IFN-gamma in a dose-dependent manner, while there was no response to TNF-alpha and IL-1beta. IFN-alpha/beta activity could be measured at a range of 9-150 U/ml, and IFN-gamma showed activity between 10 and 100 ng/ml. The reproducibility of both responses was good. The CHSE-Mx10 reporter system constitutes a versatile tool to study the induction and regulation of IFN signaling in teleost fish. A preliminary study presented herein suggests that both infectious pancreas necrosis virus (IPNV) and salmon pancreas disease virus (SPDV) may block activation of the Mx promoter in CHSE-Mx10 stimulated with IFN-alpha/beta.

  19. cAMP response element binding protein1 is essential for activation of steroyl co-enzyme a desaturase 1 (Scd1 in mouse lung type II epithelial cells.

    Directory of Open Access Journals (Sweden)

    Nisha Antony

    Full Text Available Cyclic AMP Response Element-Binding Protein 1 (Creb1 is a transcription factor that mediates cyclic adenosine 3', 5'-monophosphate (cAMP signalling in many tissues. Creb1(-/- mice die at birth due to respiratory failure and previous genome-wide microarray analysis of E17.5 Creb1(-/- fetal mouse lung identified important Creb1-regulated gene targets during lung development. The lipogenic enzymes stearoyl-CoA desaturase 1 (Scd1 and fatty acid synthase (Fasn showed highly reduced gene expression in Creb1(-/- lungs. We therefore hypothesized that Creb1 plays a crucial role in the transcriptional regulation of genes involved in pulmonary lipid biosynthetic pathways during lung development. In this study we confirmed that Scd1 and Fasn mRNA levels were down regulated in the E17.5 Creb1(-/- mouse lung while the lipogenic-associated transcription factors SrebpF1, C/ebpα and Pparγ were increased. In vivo studies using germline (Creb1(-/- and lung epithelial-specific (Creb1(EpiΔ/Δ Creb1 knockout mice showed strongly reduced Scd1, but not Fasn gene expression and protein levels in lung epithelial cells. In vitro studies using mouse MLE-15 epithelial cells showed that forskolin-mediated activation of Creb1 increased both Scd1 gene expression and protein synthesis. Additionally, MLE15 cells transfected with a dominant-negative ACreb vector blocked forskolin-mediated stimulation of Scd1 gene expression. Lipid profiling in MLE15 cells showed that dominant-negative ACreb suppressed forskolin-induced desaturation of ether linked lipids to produce plasmalogens, as well as levels of phosphatidylethanolamine, ceramide and lysophosphatidylcholine. Taken together these results demonstrate that Creb1 is essential for the induction and maintenance of Scd1 in developing fetal mouse lung epithelial cells.

  20. Cell Wall Microstructure Analysis Implicates Hemicellulose Polysaccharides in Cell Adhesion in Tomato Fruit Pericarp Parenchyma

    Institute of Scientific and Technical Information of China (English)

    Jose J. Ordaz-Ortiz; Susan E. Marcus; J. Paul Knox


    Methods developed to isolate intact cells from both unripe and ripe tomato fruit pericarp parenchyma have allowed the cell biological analysis of polysaccharide epitopes at the surface of separated cells. The LM7 pectic homoga-lacturonan epitope is a marker of the junctions of adhesion planes and intercellular spaces in parenchyma systems. The LM7 epitope persistently marked the former edge of adhesion planes at the surface of cells separated from unripe and ripened tomato fruit and also from fruits with the Cnr mutation. The LM 11 xylan epitope was associated, in sections, with cell walls lining intercellular space but the epitope was not detected at the surface of isolated cells, being lost during cell isolation. The LM15 xyloglucan epitope was present at the surface of cells isolated from unripe fruit in a pattern reflecting the former edge of cell adhesion planes/intercellular space but with gaps and apparent breaks, An equivalent pattern ofLM15 epitope occurrence was revealed at the surface of cells isolated by pectate lyase action but was not present in cells isolated from ripe fruit or from Cnr fruit. In contrast to wild-type cells, the LM5 galactan and LM21 mannan epitopes oc-curred predominantly in positions reflecting intercellular space in Cnr, suggesting a concerted alteration in cell wall mi-crostructure in response to this mutation. Galactanase and mannanase, along with pectic homogalacturonan-degrading enzymes, were capable of releasing cells from unripe fruit parenchyma. These observations indicate that hemicellulose polymers are present in architectural contexts reflecting cell adhesion and that several cell wall polysaccharide classes are likely to contribute to cell adhesion/cell separation in tomato fruit pericarp parenchyma.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Purbasha; Bosneaga, Elena; Auer, Manfred


    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.

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

    Directory of Open Access Journals (Sweden)

    Mediesse Kengne Francine


    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.

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

    Institute of Scientific and Technical Information of China (English)

    Mediesse Kengne Francine; Woguia Alice Louise; Fogue Souopgui Pythagore; Atogho-Tiedeu Barbara; Simo Gustave; Thadde Boudjeko


    Objective: To examine the total phenolic and protein contents, and the antioxidant activities of cell wall polysaccharide fractions of Stevia rebaudiana leaves.Methods: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. Three different polysaccharide-enriched fractions, namely FPE (extract with 50 mmol/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.

  4. Evidence that pulsed electric field treatment enhances the cell wall porosity of yeast cells. (United States)

    Ganeva, Valentina; Galutzov, Bojidar; Teissie, Justin


    The application of rectangular electric pulses, with 0.1-2 ms duration and field intensity of 2.5-4.5 kV/cm, to yeast suspension mediates liberation of cytoplasmic proteins without cell lysis. The aim of this study was to evaluate the effect of pulsed electric field with similar parameters on cell wall porosity of different yeast species. We found that electrically treated cells become more susceptible to lyticase digestion. In dependence on the strain and the electrical conditions, cell lysis was obtained at 2-8 times lower enzyme concentration in comparison with control untreated cells. The increase of the maximal lysis rate was between two and nine times. Furthermore, when applied at low concentration (1 U/ml), the lyticase enhanced the rate of protein liberation from electropermeabilized cells without provoking cell lysis. Significant differences in the cell surface of control and electrically treated cells were revealed by scanning electron microscopy. Data presented in this study allow us to conclude that electric field pulses provoke not only plasma membrane permeabilization, but also changes in the cell wall structure, leading to increased wall porosity.


    NARCIS (Netherlands)



    Secretion of proteins is a vital process in fungi. Because hyphal walls form a diffusion barrier for proteins, a mechanism different from diffusion probably exist to transport proteins across the wall. In Schizophyllum commune, evidence has been obtained for synthesis at the hyphal apex of wall comp

  6. Wall extensibility: its nature, measurement and relationship to plant cell growth (United States)

    Cosgrove, D. J.


    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.

  7. DBIO Best Thesis Award: Mechanics, Dynamics, and Organization of the Bacterial Cytoskeleton and Cell Wall (United States)

    Wang, Siyuan


    Bacteria come in a variety of shapes. While the peptidoglycan (PG) cell wall serves as an exoskeleton that defines the static cell shape, the internal bacterial cytoskeleton mediates cell shape by recruiting PG synthesis machinery and thus defining the pattern of cell-wall synthesis. While much is known about the chemistry and biology of the cytoskeleton and cell wall, much of their biophysics, including essential aspects of the functionality, dynamics, and organization, remain unknown. This dissertation aims to elucidate the detailed biophysical mechanisms of cytoskeleton guided wall synthesis. First, I find that the bacterial cytoskeleton MreB contributes nearly as much to the rigidity of an Escherichia coli cell as the cell wall. This conclusion implies that the cytoskeletal polymer MreB applies meaningful force to the cell wall, an idea favored by theoretical modeling of wall growth, and suggests an evolutionary origin of cytoskeleton-governed cell rigidity. Second, I observe that MreB rotates around the long axis of E. coli, and the motion depends on wall synthesis. This is the first discovery of a cell-wall assembly driven molecular motor in bacteria. Third, I prove that both cell-wall synthesis and the PG network have chiral ordering, which is established by the spatial pattern of MreB. This work links the molecular structure of the cytoskeleton and of the cell wall with organismal-scale behavior. Finally, I develop a mathematical model of cytoskeleton-cell membrane interactions, which explains the preferential orientation of different cytoskeleton components in bacteria.

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

    Directory of Open Access Journals (Sweden)

    Sebastian Zoll


    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.

  9. Theory of highly efficient multiexciton generation in type-II nanorods (United States)

    Eshet, Hagai; Baer, Roi; Neuhauser, Daniel; Rabani, Eran


    Multiexciton generation, by which more than a single electron-hole pair is generated on optical excitation, is a promising paradigm for pushing the efficiency of solar cells beyond the Shockley-Queisser limit of 31%. Utilizing this paradigm, however, requires the onset energy of multiexciton generation to be close to twice the band gap energy and the efficiency to increase rapidly above this onset. This challenge remains unattainable even using confined nanocrystals, nanorods or nanowires. Here, we show how both goals can be achieved in a nanorod heterostructure with type-II band offsets. Using pseudopotential atomistic calculation on a model type-II semiconductor heterostructure we predict the optimal conditions for controlling multiexciton generation efficiencies at twice the band gap energy. For a finite band offset, this requires a sharp interface along with a reduction of the exciton cooling and may enable a route for breaking the Shockley-Queisser limit.

  10. Ultrafast dynamics of type-II GaSb/GaAs quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Komolibus, K.; Piwonski, T.; Gradkowski, K. [Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork (Ireland); Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Reyner, C. J.; Liang, B.; Huffaker, D. L. [Department of Electrical Engineering and California NanoSystems Institute, University of California - Los Angeles, Los Angeles, California 90095 (United States); Huyet, G. [Centre for Advanced Photonics and Process Analysis, Cork Institute of Technology, Cork (Ireland); Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); National Research University of Information Technologies, Mechanics and Optics, Saint Petersburg (Russian Federation); Houlihan, J. [School of Science, Waterford Institute of Technology, Waterford (Ireland)


    In this paper, room temperature two-colour pump-probe spectroscopy is employed to study ultrafast carrier dynamics in type-II GaSb/GaAs quantum dots. Our results demonstrate a strong dependency of carrier capture/escape processes on applied reverse bias voltage, probing wavelength and number of injected carriers. The extracted timescales as a function of both forward and reverse bias may provide important information for the design of efficient solar cells and quantum dot memories based on this material. The first few picoseconds of the dynamics reveal a complex behaviour with an interesting feature, which does not appear in devices based on type-I materials, and hence is linked to the unique carrier capture/escape processes possible in type-II structures.

  11. Neural network analyses of infrared spectra for classifying cell wall architectures. (United States)

    McCann, Maureen C; Defernez, Marianne; Urbanowicz, Breeanna R; Tewari, Jagdish C; Langewisch, Tiffany; Olek, Anna; Wells, Brian; Wilson, Reginald H; Carpita, Nicholas C


    About 10% of plant genomes are devoted to cell wall biogenesis. Our goal is to establish methodologies that identify and classify cell wall phenotypes of mutants on a genome-wide scale. Toward this goal, we have used a model system, the elongating maize (Zea mays) coleoptile system, in which cell wall changes are well characterized, to develop a paradigm for classification of a comprehensive range of cell wall architectures altered during development, by environmental perturbation, or by mutation. Dynamic changes in cell walls of etiolated maize coleoptiles, sampled at one-half-d intervals of growth, were analyzed by chemical and enzymatic assays and Fourier transform infrared spectroscopy. The primary walls of grasses are composed of cellulose microfibrils, glucuronoarabinoxylans, and mixed-linkage (1 --> 3),(1 --> 4)-beta-D-glucans, together with smaller amounts of glucomannans, xyloglucans, pectins, and a network of polyphenolic substances. During coleoptile development, changes in cell wall composition included a transient appearance of the (1 --> 3),(1 --> 4)-beta-D-glucans, a gradual loss of arabinose from glucuronoarabinoxylans, and an increase in the relative proportion of cellulose. Infrared spectra reflected these dynamic changes in composition. Although infrared spectra of walls from embryonic, elongating, and senescent coleoptiles were broadly discriminated from each other by exploratory principal components analysis, neural network algorithms (both genetic and Kohonen) could correctly classify infrared spectra from cell walls harvested from individuals differing at one-half-d interval of growth. We tested the predictive capabilities of the model with a maize inbred line, Wisconsin 22, and found it to be accurate in classifying cell walls representing developmental stage. The ability of artificial neural networks to classify infrared spectra from cell walls provides a means to identify many possible classes of cell wall phenotypes. This classification

  12. Luminescence dynamics in type-II GaAs/AlAs superlattices near the type-I to type-II crossover

    DEFF Research Database (Denmark)

    Langbein, Wolfgang Werner; Kalt, H.; Hvam, Jørn Märcher


    We report on a study of the time-resolved luminescence of type-II GaAs/AlAs superlattices near the type-I to type-II crossover. In spite of the slight type-II band alignment, the luminescence is dominated by the type-I transition. This is due to the inhomogeneous broadening of the type-I transiti...

  13. Mycobacterium tuberculosis CwsA overproduction modulates cell division and cell wall synthesis. (United States)

    Plocinski, P; Martinez, L; Sarva, K; Plocinska, R; Madiraju, M; Rajagopalan, M


    We recently showed that two small membrane proteins of Mycobacterium tuberculosis, CwsA and CrgA, interact with each other, and that loss of CwsA in M. smegmatis is associated with defects in the cell division and cell wall synthesis processes. Here we show that CwsA overproduction also affected growth, cell division and cell shape of M. smegmatis and M. tuberculosis. CwsA overproduction in M. tuberculosis led to increased sensitivity to cefsulodin, a penicillin-binding protein (PBP) 1A/1B targeting beta (β) -lactam, but was unaffected by other β-lactams and vancomycin. A M. smegmatis cwsA overexpressing strain showed bulgy cells, increased fluorescent vancomycin staining and altered localization of Wag31-mCherry fusion protein. However, the levels of phosphorylated Wag31, important for optimal peptidoglycan synthesis and growth in mycobacteria, were not affected. Interestingly, CwsA overproduction in E. coli led to the formation of large rounded cells that eventually lysed whereas the overproduction of FtsZ along with CwsA reversed this phenotype. Together, our results emphasize that optimal levels of CwsA are required for regulated cell wall synthesis, hence maintenance of cell shape, and that CwsA likely interacts with and modulates the activities of other cell wall synthetic components including PBPs.

  14. 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;


    . The quadruple rwa mutant can be completely complemented with the RWA2 protein expressed under 35S promoter, indicating the functional redundancy of the RWA proteins. Nevertheless, the degree of acetylation of xylan, (gluco) mannan, and xyloglucan as well as overall cell wall acetylation is affected differently...

  15. Coronal magnetic fields from multiple type II bursts (United States)

    Honnappa, Vijayakumar; Raveesha, K. H.; Subramanian, K. R.

    Coronal magnetic fields from multiple type II bursts Vijayakumar H Doddamani1*, Raveesha K H2 and Subramanian3 1Bangalore University, Bangalore, Karnataka state, India 2CMR Institute of Technology, Bangalore, Karnataka state, India 3 Retd, Indian Institute of Astrophysics, Bangalore, Karnataka state, India Abstract Magnetic fields play an important role in the astrophysical processes occurring in solar corona. In the solar atmosphere, magnetic field interacts with the plasma, producing abundant eruptive activities. They are considered to be the main factors for coronal heating, particle acceleration and the formation of structures like prominences, flares and Coronal Mass Ejections. The magnetic field in solar atmosphere in the range of 1.1-3 Rsun is especially important as an interface between the photospheric magnetic field and the solar wind. Its structure and time dependent change affects space weather by modifying solar wind conditions, Cho (2000). Type II doublet bursts can be used for the estimation of the strength of the magnetic field at two different heights. Two type II bursts occur sometimes in sequence. By relating the speed of the type II radio burst to Alfven Mach Number, the Alfven speed of the shock wave generating type II radio burst can be calculated. Using the relation between the Alfven speed and the mean frequency of emission, the magnetic field strength can be determined at a particular height. We have used the relative bandwidth and drift rate properties of multiple type II radio bursts to derive magnetic field strengths at two different heights and also the gradient of the magnetic field in the outer corona. The magnetic field strength has been derived for different density factors. It varied from 1.2 to 2.5 gauss at a solar height of 1.4 Rsun. The empirical relation of the variation of the magnetic field with height is found to be of the form B(R) = In the present case the power law index ‘γ’ varied from -3 to -2 for variation of

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

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    António Rego


    Full Text Available 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.

  17. Isolation and molecular characterization of type I and type II feline coronavirus in Malaysia

    Directory of Open Access Journals (Sweden)

    Amer Alazawy


    Full Text Available Abstract Background Feline infectious peritonitis virus (FIPV and feline enteric coronavirus (FECV are two important coronaviruses of domestic cat worldwide. Although FCoV is prevalent among cats; the fastidious nature of type I FCoV to grow on cell culture has limited further studies on tissue tropism and pathogenesis of FCoV. While several studies reported serological evidence for FCoV in Malaysia, neither the circulating FCoV isolated nor its biotypes determined. This study for the first time, describes the isolation and biotypes determination of type I and type II FCoV from naturally infected cats in Malaysia. Findings Of the total number of cats sampled, 95% (40/42 were RT-PCR positive for FCoV. Inoculation of clinical samples into Crandell feline kidney cells (CrFK, and Feline catus whole fetus-4 cells (Fcwf-4, show cytopathic effect (CPE characterized by syncytial cells formation and later cell detachment. Differentiation of FCoV biotypes using RT-PCR assay revealed that, 97.5% and 2.5% of local isolates were type I and type II FCoV, respectively. These isolates had high sequence homology and phylogenetic similarity with several FCoV isolates from Europe, South East Asia and USA. Conclusions This study reported the successful isolation of local type I and type II FCoV evident with formation of cytopathic effects in two types of cell cultures namely the CrFK and Fcwf-4 , where the later cells being more permissive. However, the RT-PCR assay is more sensitive in detecting the antigen in suspected samples as compared to virus isolation in cell culture. The present study indicated that type I FCoV is more prevalent among cats in Malaysia.

  18. Type II SOCS as a feedback repressor for GH-induced Igf1 expression in carp hepatocytes. (United States)

    Jiang, Xue; Xiao, Jia; He, Mulan; Ma, Ani; Wong, Anderson O L


    Type II suppressor of cytokine signaling (SOCS) serve as feedback repressors for cytokines and are known to inhibit growth hormone (GH) actions. However, direct evidence for SOCS modulation of GH-induced insulin-like growth factor 1 (Igf1) expression is lacking, and the post-receptor signaling for SOCS expression at the hepatic level is still unclear. To shed light on the comparative aspects of SOCS in GH functions, grass carp was used as a model to study the role of type II SOCS in GH-induced Igf1 expression. Structural identity of type II SOCS, Socs1-3 and cytokine-inducible SH2-containing protein (Cish), was established in grass carp by 5'/3'-RACE, and their expression at both transcript and protein levels were confirmed in the liver by RT-PCR and LC/MS/MS respectively. In carp hepatocytes, GH treatment induced rapid phosphorylation of JAK2, STATs, MAPK, PI3K, and protein kinase B (Akt) with parallel rises in socs1-3 and cish mRNA levels, and these stimulatory effects on type II SOCS were shown to occur before the gradual loss of igf1 gene expression caused by prolonged exposure of GH. Furthermore, GH-induced type II SOCS gene expression could be negated by inhibiting JAK2, STATs, MEK1/2, P38 (MAPK), PI3K, and/or Akt respectively. In CHO cells transfected with carp GH receptor, over-expression of these newly cloned type II SOCS not only suppressed JAK2/STAT5 signaling with GH treatment but also inhibited GH-induced grass carp Igf1 promoter activity. These results, taken together, suggest that type II SOCS could be induced by GH in the carp liver via JAK2/STATs, MAPK, and PI3K/Akt cascades and serve as feedback repressors for GH signaling and induction of igf1 gene expression.

  19. Osmotic Stress Suppresses Cell Wall Stiffening and the Increase in Cell Wall-Bound Ferulic and Diferulic Acids in Wheat Coleoptiles. (United States)

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


    The relationship between the mechanical properties of cell walls and the levels of wall-bound ferulic (FA) and diferulic (DFA) acids was investigated in wheat (Triticum aestivum L.) coleoptiles grown under osmotic stress (60 mM polyethylene glycol [PEG] 4000) conditions. The cell walls of stressed coleoptiles remained extensible compared with those of the unstressed ones. The contents of wall-bound FA and DFA increased under unstressed conditions, but the increase was substantially reduced by osmotic stress. In response to PEG removal, these contents increased and reached almost the same levels as those of the unstressed coleoptiles. A close correlation was observed between the contents of FA and DFA and the mechanical properties of cell walls. The activities of phenylalanine ammonia-lyase and tyrosine ammonia-lyase increased rapidly under unstressed conditions. Osmotic stress substantially reduced the increases in enzyme activities. When PEG was removed, however, the enzyme activities increased rapidly. There was a close correlation between the FA levels and enzyme activities. These results suggest that in osmotically stressed wheat coleoptiles, reduced rates of increase in phenylalanine ammonia-lyase and tyrosine ammonia-lyase activities suppress phenylpropanoid biosynthesis, resulting in the reduced level of wall-bound FA that, in turn, probably causes the reduced level of DFA and thereby maintains cell wall extensibility. PMID:12223657

  20. Cell-free layer and wall shear stress variation in microvessels. (United States)

    Yin, Xuewen; Zhang, Junfeng


    In this study, we simulated multiple red blood cells flowing through straight microvessels with the immersed-boundary lattice-Boltzmann model to examine the shear stress variation on the microvessel surface and its relation to the properties of cell-free layer. Significant variation in shear stress has been observed due to the irregular configuration of blood cells flowing near the microvessel wall. A low shear stress is typically found at locations where there is a cell flowing close to the wall, and a large shear stress at locations with a relatively wide gap between cell and wall. This relationship between the shear stress magnitude and the distance between cell and wall has been attributed to the reverse pressure difference developed between the front and rear sides of a cell flowing near the vessel wall. We further studied the effects of several hemodynamic factors on the variation of shear stress, including the cell deformability, the flow rate, and the aggregation among red blood cells. These simulations show that the shear stress variation is less profound in situations with wider cell-free layers, since the reverse pressure difference around the edge cells is less evident, and the influence of this pressure difference on wall shear stress becomes weaker. This study also demonstrates the complexity of the flow field in the gap between cell and wall. More precise experimental techniques are required accurately measure such shear stress variation in microcirculation.

  1. Primary abdominal wall clear cell carcinoma arising from incisional endometriosis

    Institute of Scientific and Technical Information of China (English)

    Burcu Gundogdu; Isin Ureyen; Gunsu Kimyon; Hakan Turan; Nurettin Boran; Gokhan Tulunay; Dilek Bulbul; Taner Turan; M Faruk Kose


    A 49 year-old patient with the complaint of a mass located in the caesarean scar was admitted. There was a fixed mass 30í30 mm in diameter with regular contour located at the right corner of the pfannenstiel incision. Computed tomography revealed a (40í50í50) mm solid mass lesion with margins that cannot be distinguished from the uterus, bladder and small intestines and a heterogeneous mass lesion (50í45í55) mm in diameter, located in the right side of the anterior abdominal wall. Cytoreductive surgery including total abdominal hysterectomy and bilateral salpingo-oophorectomy was performed. Final pathology was clear cell carcinoma. Clear cell carcinoma arising from an extraovarian endometriotic focus was diagnosed and the patient received 6 cycles paclitaxel-carboplatin chemotherapy as adjuvant treatment. The patient who was lost to follow-up applied to our clinic 2 years after surgery with a recurrent mass in the left inguinal region. After 3 cycles of chemotherapy, the patient's tumoral mass in the left inguinal region was excised. The result of the pathology was carcinoma metastasis. It is decided that the following treatment of the patient should be palliative radiation therapy. The patient who underwent palliative radiation therapy died of disease after 4 months of the second operation.

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

    Directory of Open Access Journals (Sweden)

    Pedersen Henriette L


    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

  3. On the Covariant Quantization of Type II Superstrings

    CERN Document Server

    Guttenberg, S; Kreuzer, M; Guttenberg, Sebastian; Knapp, Johanna; Kreuzer, Maximilian


    In a series of papers Grassi, Policastro, Porrati and van Nieuwenhuizen have introduced a new method to covariantly quantize the GS-superstring by constructing a resolution of the pure spinor constraint of Berkovits' approach. Their latest version is based on a gauged WZNW model and a definition of physical states in terms of relative cohomology groups. We first put the off-shell formulation of the type II version of their ideas into a chirally split form and directly construct the free action of the gauged WZNW model, thus circumventing some complications of the super group manifold approach to type II. Then we discuss the BRST charges that define the relative cohomology and the N=2 superconformal algebra. A surprising result is that nilpotency of the BRST charge requires the introduction of another quartet of ghosts.

  4. Two different molecular conformations found in chitosan type II salts. (United States)

    Lertworasirikul, Amornrat; Tsue, Shin-ichiro; Noguchi, Keiichi; Okuyama, Kenji; Ogawa, Kozo


    The type II structure of chitosan acidic salts prepared from crab tendon in solid state was studied using an X-ray fiber diffraction technique together with the linked-atom least-squares (LALS) technique. The cylindrical Patterson method was applied to confirm the molecular conformation of the chitosan. It was shown that there are two different helical conformations for type II salts. One is the relaxed twofold helix having a tetrasaccharide as an asymmetric unit as found in chitosan.HCl salt, which was previously reported as a conformation of chitosan.HCOOH salt. The other is the fourfold helix having a disaccharide as an asymmetric unit newly found in chitosan.HI salt.

  5. Depression among patients with type-II diabetes mellitus. (United States)

    Khan, Mohammad Akmal; Sultan, Sayed Mohammad; Nazli, Rubina; Akhtar, Tasleem; Khan, Mudasar Ahmad; Sher, Nabila; Aslam, Hina


    This study aimed to determine the frequency of depression among patients with type-II diabetes mellitus in Peshawar at Khyber Teaching Hospital, Peshawar, from March to September 2010. Depression was assessed by using Beck Depressive Inventory-II (BDI-II). Out of 140 patients with type-II diabetes, 85 (61%) were women and 55 (39%) were men. Mean age was 45±7.45 years. Eighty four (60%) patients presented with severe depression. Depression was higher in females than males and widows. Depression was high in diabetic patients, especially in females and widows. It is of essence that psychiatric attention may be necessary to be incorporated in diabetes care both for prevention and treatment.

  6. UBVRIz Light Curves of 51 Type II Supernovae

    CERN Document Server

    Galbany, Lluís; Phillips, Mark M; Suntzeff, Nicholas B; Maza, José; de Jaeger, Thomas; Moraga, Tania; González-Gaitán, Santiago; Krisciunas, Kevin; Morrell, Nidia I; Thomas-Osip, Joanna; Krzeminski, Wojtek; González, Luis; Antezana, Roberto; Wischnjewski, Marina; McCarthy, Patrick; Anderson, Joseph P; Gutiérrez, Claudia P; Stritzinger, Maximilian; Folatelli, Gastón; Anguita, Claudio; Galaz, Gaspar; Green, Elisabeth M; Impey, Chris; Kim, Yong-Cheol; Kirhakos, Sofia; Malkan, Mathew A; Mulchaey, John S; Phillips, Andrew C; Pizzella, Alessandro; Prosser, Charles F; Schmidt, Brian P; Schommer, Robert A; Sherry, William; Strolger, Louis-Gregory; Wells, Lisa A; Williger, Gerard M


    We present a compilation of UBV RIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986 to 2003: the Cerro Tololo Supernova Survey, the Calan/Tololo Supernova Program (C&T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being thus shorter (longer) for larger (smaller) s values.


    Energy Technology Data Exchange (ETDEWEB)

    Galbany, Lluis; Hamuy, Mario; Jaeger, Thomas de; Moraga, Tania; González-Gaitán, Santiago; Gutiérrez, Claudia P. [Millennium Institute of Astrophysics, Universidad de Chile (Chile); Phillips, Mark M.; Morrell, Nidia I.; Thomas-Osip, Joanna [Carnegie Observatories, Las Campanas Observatory, Casilla 60, La Serena (Chile); Suntzeff, Nicholas B. [Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Maza, José; González, Luis; Antezana, Roberto; Wishnjewski, Marina [Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Las Condes, Santiago (Chile); Krisciunas, Kevin [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, Texas A. and M. University, Department of Physics and Astronomy, 4242 TAMU, College Station, TX 77843 (United States); Krzeminski, Wojtek [N. Copernicus Astronomical Center, ul. Bartycka 18, 00-716 Warszawa (Poland); McCarthy, Patrick [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Anderson, Joseph P. [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago (Chile); Stritzinger, Maximilian [Department of Physics and Astronomy, Aarhus University (Denmark); Folatelli, Gastón, E-mail: [Instituto de Astrofísica de La Plata (IALP, CONICET) (Argentina); and others


    We present a compilation of UBVRIz light curves of 51 type II supernovae discovered during the course of four different surveys during 1986–2003: the Cerro Tololo Supernova Survey, the Calán/Tololo Supernova Program (C and T), the Supernova Optical and Infrared Survey (SOIRS), and the Carnegie Type II Supernova Survey (CATS). The photometry is based on template-subtracted images to eliminate any potential host galaxy light contamination, and calibrated from foreground stars. This work presents these photometric data, studies the color evolution using different bands, and explores the relation between the magnitude at maximum brightness and the brightness decline parameter (s) from maximum light through the end of the recombination phase. This parameter is found to be shallower for redder bands and appears to have the best correlation in the B band. In addition, it also correlates with the plateau duration, being shorter (longer) for larger (smaller) s values.

  8. Gain spectroscopy of a type-II VECSEL chip

    CERN Document Server

    Lammers, Christian; Berger, Christian; Möller, Christoph; Fuchs, Christian; Perez, Antje Ruiz; Rahimi-Iman, Arash; Hader, Jörg; Moloney, Jerome; Stolz, Wolfgang; Koch, Stephan W; Koch, Martin


    Using optical pump-white light probe spectroscopy the gain dynamics is investigated for a VECSEL chip which is based on a type-II heterostructure. The active region the chip consists of a GaAs/(GaIn)As/Ga(AsSb)/(GaIn)As/GaAs multiple quantum well. For this structure, a fully microscopic theory predicts a modal room temperature gain at a wavelength of 1170 nm, which is confirmed by experimental spectra. The results show a gain buildup on the type-II chip which is delayed relative to that of a type-I chip. This slower gain dynamics is attributed to a diminished cooling rate arising from reduced electron-hole scattering.

  9. Multicolor Oservations of the Type II Cepheid Prototype W Virginis (United States)

    Templeton, Matthew R.; Henden, A. A.; Crawford, T.; James, R.; Bonnardeau, M.; Wells, D.


    We present preliminary results of the AAVSO's six-month photometric campaign on the bright, pulsating variable star W Virginis, class prototype of the Type II Cepheid variables. This campaign was organized in support of separate spectroscopic observations (Wallerstein et al., in preparation), but these photometric data also stand alone as a valuable, recent, multicolor light curve of this object. Observations were obtained by several amateur and professional observers using a variety of equipment; data are primarily in the V filter, but include two complete pulsation cycles in the BVRcIc filters. We present lightand color-curves of this star, and compare our results to previous observational and theoretical results on W Vir and the Type II Cepheids.

  10. Subclinical onychomycosis in patients with type II diabetes

    Directory of Open Access Journals (Sweden)

    Amira Elbendary


    Full Text Available Fungal organisms could be present in the nail without any clinical manifestations. As onychomycosis in diabetics has more serious complications, early detection of such infection could be helpful to prevent them. We aim in this study to assess the possibility of detecting subclinical onychomycosis in type II diabetic patients and addressing possible associated neuropathy. A cross sectional, observational study included patients with type II diabetes with normal big toe nail. All were subjected to nail clipping of the big toe nail, followed by staining with Hematoxylin and Eosin and Periodic-Acid-Schiff (PAS stains and examined microscopically. A total of 106 patients were included, fungal infection was identified in eight specimens, all were uncontrolled diabetes, and six had neuropathy. Using the nail clipping and microscopic examination with PAS stain to detect such subclinical infection could be an applicable screening test for diabetic patients, for early detection and management of onychomycosis.

  11. Instability in the magnetic field penetration in type II superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Isaías G. de, E-mail:


    Under the view of the time-dependent Ginzburg–Landau theory we have investigated the penetration of the magnetic field in the type II superconductors. We show that the single vortices, situated along the borderline, between the normal region channel and the superconducting region, can escape to regions still empty of vortices. We show that the origin of this process is the repulsive nature of vortex–vortex interaction, in addition to the non-homogeneous distribution of the vortices along the normal region channel. Using London theory we explain the extra gain of kinetic energy by the vortices situated along this borderline. - Highlights: • TDGL is used to study the magnetic field penetration in type II superconductors. • Instability process is found during the magnetic field penetration. • Vortices along the front of the normal region escape to superconducting region. • We explain the extra-gain of kinetic energy by vortices along the borderline.

  12. Theoretical models for Type I and Type II supernova

    Energy Technology Data Exchange (ETDEWEB)

    Woosley, S.E.; Weaver, T.A.


    Recent theoretical progress in understanding the origin and nature of Type I and Type II supernovae is discussed. New Type II presupernova models characterized by a variety of iron core masses at the time of collapse are presented and the sensitivity to the reaction rate /sup 12/C(..cap alpha..,..gamma..)/sup 16/O explained. Stars heavier than about 20 M/sub solar/ must explode by a ''delayed'' mechanism not directly related to the hydrodynamical core bounce and a subset is likely to leave black hole remnants. The isotopic nucleosynthesis expected from these massive stellar explosions is in striking agreement with the sun. Type I supernovae result when an accreting white dwarf undergoes a thermonuclear explosion. The critical role of the velocity of the deflagration front in determining the light curve, spectrum, and, especially, isotopic nucleosynthesis in these models is explored. 76 refs., 8 figs.

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

    Directory of Open Access Journals (Sweden)

    Vesna Hadži-Tašković Šukalović


    Full Text Available 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.

  14. Painful keratoderma and photophobia: hallmarks of tyrosinemia type II. (United States)

    Rabinowitz, L G; Williams, L R; Anderson, C E; Mazur, A; Kaplan, P


    Tyrosinemia type II (Richner-Hanhart syndrome), which is caused by a deficiency of hepatic tyrosine aminotransferase, results in elevated plasma and urinary tyrosine concentrations. We describe a young boy who was seen at 6 months of age with red eyes, photophobia, and eye pain that were not suspected to be caused by tyrosinemia II until painful plantar keratoderma developed at 2 1/2 years of age. Treatment with a diet low in tyrosine and phenylalanine reversed the manifestations of the disease.

  15. Tyrosinemia type II: a challenge for ophthalmologists and dermatologists. (United States)

    Benoldi, D; Orsoni, J B; Allegra, F


    Tyrosinemia type II was suspected in a 13-month-old child with recurrent photophobia, tearing, and hyperkeratotic lesions on the palms and soles. Laboratory tests revealed high tyrosine levels in blood and urine. All the symptoms promptly improved after the institution of a low tyrosine diet. We emphasize the importance of an early diagnosis in order to avoid the risk of mental retardation in these patients.

  16. Gaia16alo is a Type II SN (United States)

    Fraser, M.; Hodgkin, S. T.; Mattila, S.; Harrison, D.; Wyrzykowski, L.; Kostrzewa-Rutkowska, Z.; Blagorodnova, N.


    Gaia16alo (aka PS16cct) was observed using the robotic Liverpool Telescope + SPRAT (R~350; 400-800 nm) on the night of 2016 May 6. The spectrum was compared to a set of templates using SNID (Blondin & Tonry, 2007, ApJ, 666, 1024), and we find a best match to a range of Type II SNe at z=0.03.


    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Michael L., E-mail: [Advanced Technologies Group, West Virginia High Technology Consortium Foundation, 1000 Galliher Drive, Fairmont, WV 26554 (United States)


    A 2.5D, time-dependent magnetohydrodynamic model is used to test the proposition that observed type II spicule velocities can be generated by a Lorentz force under chromospheric conditions. It is found that current densities localized on observed space and time scales of type II spicules and that generate maximum magnetic field strengths {<=}50 G can generate a Lorentz force that accelerates plasma to terminal velocities similar to those of type II spicules. Maximum vertical flow speeds are {approx}150-460 km s{sup -1}, horizontally localized within {approx}2.5-10 km from the vertical axis of the spicule, and comparable to slow solar wind speeds, suggesting that significant solar wind acceleration occurs in type II spicules. Horizontal speeds are {approx}20 times smaller than vertical speeds. Terminal velocity is reached {approx}100 s after acceleration begins. The increase in the mechanical and thermal energy of the plasma during acceleration is (2-3) Multiplication-Sign 10{sup 22} ergs. The radial component of the Lorentz force compresses the plasma during the acceleration process by factors as large as {approx}100. The Joule heating flux generated during this process is essentially due to proton Pedersen current dissipation and can be {approx}0.1-3.7 times the heating flux of {approx}10{sup 6} ergs cm{sup -2} s{sup -1} associated with middle-upper chromospheric emission. About 84%-94% of the magnetic energy that accelerates and heats the spicules is converted into bulk flow kinetic energy.

  18. Headache and Decompression Sickness: Type I or Type II? (United States)


    neurological exam was normal. Recompression with 100% oxygen produced relief within fifteen minutes. Follow up revealed no recurrence . Case 2 A twenty-seven...Follow up revealed no recurrence . Both cases pose an intriguing question. Should headache always be considered Type II DCS? DCS has a wide range of...with the supporting basis for this alternative view. The background for this paper is based on orthodontic and osteopathic medicine. For years

  19. Evaluation of Oral Health in Type II Diabetes Mellitus Patients


    Rathy Ravindran; M.G. Deepa; A.K. Sruthi; Cherian Kuruvila; Priya, S.; S.Sunil; Joseph Edward; G Roopesh


    Background: Oral cav ity re flects the general health status of a person and diagnosing and treating oral manifestations of systemic disease pose a greater challenge. Even though there is strong evidence that supports the relationship between oral health and diabetes mellitus, oral health awareness is lacking among diabetic patients and health professionals. The present study was undertaken to determine the oral health status in type II diabetic patients and also...

  20. Superspace with manifest T-duality from type II superstring

    CERN Document Server

    Hatsuda, Machiko; Siegel, Warren


    A superspace formulation of type II superstring background with manifest T-duality symmetry is presented. This manifestly T-dual formulation is constructed in a space spanned by two sets of nondegenerate super-Poincare algebra. Supertorsion constraints are obtained from consistency of the kappa-symmetric Virasoro constraints. All superconnections and vielbein fields are solved in terms of a prepotential which is one of the vielbein components. AdS5xS5 background is explained in this formulation.

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

    Directory of Open Access Journals (Sweden)

    Elizabeth A. Berry


    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.


    Estevez, José M; Leonardi, Patricia I; Alberghina, Josefina S


    Cell wall changes in vegetative and suffultory cells (SCs) and in oogonial structures from Oedogonium bharuchae N. D. Kamat f. minor Vélez were characterized using monoclonal antibodies against several carbohydrate epitopes. Vegetative cells and SCs develop only a primary cell wall (PCW), whereas mature oogonial cells secrete a second wall, the oogonium cell wall (OCW). Based on histochemical and immunolabeling results, (1→4)-β-glucans in the form of crystalline cellulose together with a variable degree of Me-esterified homogalacturonans (HGs) and hydroxyproline-rich glycoprotein (HRGP) epitopes were detected in the PCW. The OCW showed arabinosides of the extensin type and low levels of arabinogalactan-protein (AGP) glycans but lacked cellulose, at least in its crystalline form. Surprisingly, strong colabeling in the cytoplasm of mature oogonia cells with three different antibodies (LM-5, LM-6, and CCRC-M2) was found, suggesting the presence of rhamnogalacturonan I (RG-I)-like structures. Our results are discussed relating the possible functions of these cell wall epitopes with polysaccharides and O-glycoproteins during oogonium differentiation. This study represents the first attempt to characterize these two types of cell walls in O. bharuchae, comparing their similarities and differences with those from other green algae and land plants. This work represents a contribution to the understanding of how cell walls have evolved from simple few-celled to complex multicelled organisms.

  3. Immuno and Affinity Cytochemical Analysis of Cell Wall Composition in the Moss Physcomitrella patens. (United States)

    Berry, Elizabeth A; Tran, Mai L; Dimos, Christos S; Budziszek, Michael J; Scavuzzo-Duggan, Tess R; Roberts, Alison W


    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 homogalactuonan 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 heterogneity. 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.

  4. Amylin Uncovered: A Review on the Polypeptide Responsible for Type II Diabetes

    Directory of Open Access Journals (Sweden)

    Karen Pillay


    Full Text Available Amylin is primarily responsible for classifying type II diabetes as an amyloid (protein misfolding disease as it has great potential to aggregate into toxic nanoparticles, thereby resulting in loss of pancreatic -cells. Although type II diabetes is on the increase each year, possibly due to bad eating habits of modern society, research on the culprit for this disease is still in its early days. In addition, unlike the culprit for Alzheimer’s disease, amyloid -peptide, amylin has failed to receive attention worthy of being featured in an abundance of review articles. Thus, the aim of this paper is to shine the spotlight on amylin in an attempt to put it onto the top of researchers’ to-do list since the secondary complications of type II diabetes have far-reaching and severe consequences on public health both in developing and fully developed countries alike. This paper will cover characteristics of the amylin aggregates, mechanisms of toxicity, and a particular focus on inhibitors of toxicity and techniques used to assess these inhibitors.

  5. Detection of 2 immunoreactive antigens in the cell wall of Sporothrix brasiliensis and Sporothrix globosa. (United States)

    Ruiz-Baca, Estela; Hernández-Mendoza, Gustavo; Cuéllar-Cruz, Mayra; Toriello, Conchita; López-Romero, Everardo; Gutiérrez-Sánchez, Gerardo


    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.


    Directory of Open Access Journals (Sweden)

    TABORDA Valeria B.A.


    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.

  7. Modification of cell wall architecture of wheat coleoptiles grown under hypergravity conditions. (United States)

    Wakabayashi, Kazuyuki; Soga, Kouichi; Kamisaka, Seiichiro; Hoson, Takayuki


    Cell wall structure of wheat coleoptiles grown under continuous hypergravity (300 g) conditions was investigated. Length of coleoptiles exposed to hypergravity for 2-4 days from germination stage was 60-70% of that of 1 g control. The amounts of cell wall polysaccharides substantially increased during the incubation period both in 1 g control and hypergravity-treated coleoptiles. As a results, the levels of cell wall polysaccharides per unit length of coleoptile, which mean the thickness of cell walls, largely increased under hypergravity conditions. The major sugar components of the hemicellulose fraction, a polymer fraction extracted from cell walls with strong alkali, were arabinose (Ara), xylose (Xyl) and glucose (Glc). The molar ratios of Ara and Xyl to Glc in hypergravity-treated coleoptiles were higher than those in control coleoptiles. Furthermore, the fractionation of hemicellulosic polymers into the neutral and acidic polymers by the anion-exchange column showed that the levels of acidic polymers in cell walls of hypergravity-treated coleoptiles were higher than those of control coleoptiles. These results suggest that hypergravity stimuli bias the synthesis of hemicellulosic polysaccharides and increase the proportion of acidic polymers, such as arabinoxylans, in cell walls of wheat coleoptiles. These structural changes in cell walls may contribute to plant resistance to hypergravity stimuli.

  8. Cell wall composition as a maize defense mechanism against corn borers. (United States)

    Barros-Rios, Jaime; Malvar, Rosa A; Jung, Hans-Joachim G; Santiago, Rogelio


    European and Mediterranean corn borers are two of the most economically important insect pests of maize (Zea mays L.) in North America and southern Europe, respectively. Cell wall structure and composition were evaluated in pith and rind tissues of resistant and susceptible inbred lines as possible corn borer resistance traits. Composition of cell wall polysaccharides, lignin concentration and composition, and cell wall bound forms of hydroxycinnamic acids were measured. As expected, most of the cell wall components were found at higher concentrations in the rind than in the pith tissues, with the exception of galactose and total diferulate esters. Pith of resistant inbred lines had significantly higher concentrations of total cell wall material than susceptible inbred lines, indicating that the thickness of cell walls could be the initial barrier against corn borer larvae attack. Higher concentrations of cell wall xylose and 8-O-4-coupled diferulate were found in resistant inbreds. Stem tunneling by corn borers was negatively correlated with concentrations of total diferulates, 8-5-diferulate and p-coumarate esters. Higher total cell wall, xylose, and 8-coupled diferulates concentrations appear to be possible mechanisms of corn borer resistance.

  9. 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.


    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 se

  10. Cell wall growth during elongation and division : one ring to bind them?

    NARCIS (Netherlands)

    Scheffers, Dirk-Jan


    The role of the cell division protein FtsZ in bacterial cell wall (CW) synthesis is believed to be restricted to localizing proteins involved in the synthesis of the septal wall. Elsewhere, compelling evidence is provided that in Caulobacter crescentus, FtsZ plays an additional role in CW synthesis

  11. Structure of Plant Cell Walls : XXVI. The Walls of Suspension-Cultured Sycamore Cells Contain a Family of Rhamnogalacturonan-I-Like Pectic Polysaccharides. (United States)

    Ishii, T; Thomas, J; Darvill, A; Albersheim, P


    Considerable information has been obtained about the primary structures of suspension-cultured sycamore (Acer pseudoplatanus) cell-wall pectic polysaccharides, i.e. rhamnogalacturonan I, rhamnogalacturonan II, and homogalacturonan. However, these polysaccharides, which are solubilized from the walls by endo-alpha-1,4-polygalacturonase, account for only about half of the pectic polysaccharides known to be present in sycamore cell walls. We now report that, after exhaustive treatment with endo-alpha-1,4-polygalacturonase, additional pectic polysaccharides were extracted from sycamore cell walls by treatment with Na(2)CO(3) at 1 and 22 degrees C. These previously uncharacterized polysaccharides accounted for approximately 4% of the cell wall. Based on the glycosyl and glycosyl-linkage compositions and the nature of the products obtained by treating the quantitatively predominant NaCO(3)-extracted polysaccharides with lithium metal dissolved in ethylenediamine, the polysaccharides were found to strongly resemble rhamnogalacturonan I. However, unlike rhamnogalacturonan I that characteristically had equal amounts of 2- and 2,4-linked rhamnosyl residues in its backbone, the polysaccharides extracted in Na(2)CO(3) at 1 degrees C had markedly disparate ratios of 2- to 2,4-linked rhamnosyl residues. We concluded that polysaccharides similar to rhamnogalacturonan I but with different degrees of branching are present in the walls of suspension-cultured sycamore cells.

  12. Trans-Golgi Network-An Intersection of Trafficking Cell Wall Components

    Institute of Scientific and Technical Information of China (English)

    Natasha Worden; Eunsook Park; Georgia Drakakaki


    The cell wall,a crucial cell compartment,is composed of a network of polysaccharides and proteins,providing structural support and protection from external stimuli.While the cell wall structure and biosynthesis have been extensively studied,very little is known about the transport of polysaccharides and other components into the developing cell wall.This review focuses on endomembrane trafficking pathways involved in cell wall deposition.Cellulose synthase complexes are assembled in the Golgi,and are transported in vesicles to the plasma membrane.Non-cellulosic polysaccharides are synthesized in the Golgi apparatus,whereas cellulose is produced by enzyme complexes at the plasma membrane.Polvsaccharides and enzymes that are involved in cell wall modification and assembly are transported by distinct vesicle types to their destinations; however,the precise mechanisms involved in selection,sorting and delivery remain to be identified.The endomembrane system orchestrates the delivery of Golgi-derived and possibly endocytic vesicles carrying cell wall and cell membrane components to the newly-formed cell plate.However,the nature of these vesicles,their membrane compositions,and the timing of their delivery are largely unknown.Emerging technologies such as chemical genomics and proteomics are promising avenues to gain insight into the trafficking of cell wall components.

  13. Clinostation influence on regeneration of cell wall in Solanum Tuberosum L. protoplasts (United States)

    Nedukha, Elena M.; Sidorov, V. A.; Samoylov, V. M.


    Regeneration of cell walls in protoplasts was investigated using light- and electronmicroscopic methods. The protoplasts were isolated from mesophyll of Solanum tuberosum leaves and were cultivated on the horizontal low rotating clinostat (2 rpm) and in control for 10 days. Using a fluorescent method (with Calcofluor white) it was demonstrated that changes in vector gravity results in an regeneration inhibition of cell wall. With electron-microscopical and electro-cytochemical methods (staining with alcianum blue) dynamics of the regeneration of cell walls in protoplasts was studied; carbohydrate matrix of cell walls is deposited at the earliest stages of this process. The influence of microgravity on the cell wall regeneration is discussed in higher plants.

  14. Interactions between grape skin cell wall material and commercial enological tannins. Practical implications. (United States)

    Bautista-Ortín, Ana Belén; Cano-Lechuga, Mario; Ruiz-García, Yolanda; Gómez-Plaza, Encarna


    Commercial enological tannins were used to investigate the role that cell wall material plays in proanthocyanidin adsorption. Insoluble cell wall material, prepared from the skin of Vitis vinifera L. cv. Monastrell berries, was combined with solutions containing six different commercial enological tannins (proanthocyanidin-type tannins). Analysis of the proanthocyanidins in the solution, after fining with cell wall material, using phloroglucinolysis and size exclusion chromatography, provided quantitative and qualitative information on the non-adsorbed compounds. Cell wall material showed strong affinity for the proanthocyanidins, one of the commercial tannins being bound up to 61% in the experiment. Comparison of the molecular mass distribution of the commercial enological tannins in solution, before and after fining, suggested that cell walls affinity for proanthocyanidins was more related with the proanthocyanidin molecular mass than with their percentage of galloylation. These interactions may have some enological implications, especially as regards the time of commercial tannins addition to the must/wine.

  15. XIAP discriminates between type I and type II FAS-induced apoptosis. (United States)

    Jost, Philipp J; Grabow, Stephanie; Gray, Daniel; McKenzie, Mark D; Nachbur, Ueli; Huang, David C S; Bouillet, Philippe; Thomas, Helen E; Borner, Christoph; Silke, John; Strasser, Andreas; Kaufmann, Thomas


    FAS (also called APO-1 and CD95) and its physiological ligand, FASL, regulate apoptosis of unwanted or dangerous cells, functioning as a guardian against autoimmunity and cancer development. Distinct cell types differ in the mechanisms by which the 'death receptor' FAS triggers their apoptosis. In type I cells, such as lymphocytes, activation of 'effector caspases' by FAS-induced activation of caspase-8 suffices for cell killing, whereas in type II cells, including hepatocytes and pancreatic beta-cells, caspase cascade amplification through caspase-8-mediated activation of the pro-apoptotic BCL-2 family member BID (BH3 interacting domain death agonist) is essential. Here we show that loss of XIAP (X-chromosome linked inhibitor of apoptosis protein) function by gene targeting or treatment with a second mitochondria-derived activator of caspases (SMAC, also called DIABLO; direct IAP-binding protein with low pI) mimetic drug in mice rendered hepatocytes and beta-cells independent of BID for FAS-induced apoptosis. These results show that XIAP is the critical discriminator between type I and type II apoptosis signalling and suggest that IAP inhibitors should be used with caution in cancer patients with underlying liver conditions.

  16. Generation of hydroxyl radical in isolated pea root cell wall, and the role of cell wall-bound peroxidase, Mn-SOD and phenolics in their production. (United States)

    Kukavica, Biljana; Mojovic, Milos; Vuccinic, Zeljko; Maksimovic, Vuk; Takahama, Umeo; Jovanovic, Sonja Veljovic


    The hydroxyl radical produced in the apoplast has been demonstrated to facilitate cell wall loosening during cell elongation. Cell wall-bound peroxidases (PODs) have been implicated in hydroxyl radical formation. For this mechanism, the apoplast or cell walls should contain the electron donors for (i) H(2)O(2) formation from dioxygen; and (ii) the POD-catalyzed reduction of H(2)O(2) to the hydroxyl radical. The aim of the work was to identify the electron donors in these reactions. In this report, hydroxyl radical (.OH) generation in the cell wall isolated from pea roots was detected in the absence of any exogenous reductants, suggesting that the plant cell wall possesses the capacity to generate .OH in situ. Distinct POD and Mn-superoxide dismutase (Mn-SOD) isoforms different from other cellular isoforms were shown by native gel electropho-resis to be preferably bound to the cell walls. Electron paramagnetic resonance (EPR) spectroscopy of cell wall isolates containing the spin-trapping reagent, 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO), was used for detection of and differentiation between .OH and the superoxide radical (O(2)(-).). The data obtained using POD inhibitors confirmed that tightly bound cell wall PODs are involved in DEPMPO/OH adduct formation. A decrease in DEPMPO/OH adduct formation in the presence of H(2)O(2) scavengers demonstrated that this hydroxyl radical was derived from H(2)O(2). During the generation of .OH, the concentration of quinhydrone structures (as detected by EPR spectroscopy) increased, suggesting that the H(2)O(2) required for the formation of .OH in isolated cell walls is produced during the reduction of O(2) by hydroxycinnamic acids. Cell wall isolates in which the proteins have been denaturated (including the endogenous POD and SOD) did not produce .OH. Addition of exogenous H(2)O(2) again induced the production of .OH, and these were shown to originate from the Fenton reaction with tightly bound metal ions

  17. The Cell Wall Lipid PDIM Contributes to Phagosomal Escape and Host Cell Exit of Mycobacterium tuberculosis (United States)

    Quigley, Jeff; Hughitt, V. Keith; Velikovsky, Carlos A.; Mariuzza, Roy A.


    ABSTRACT The cell wall of Mycobacterium tuberculosis is composed of unique lipids that are important for pathogenesis. Indeed, the first-ever genetic screen in M. tuberculosis identified genes involved in the biosynthesis and transport of the cell wall lipid PDIM (phthiocerol dimycocerosates) as crucial for the survival of M. tuberculosis in mice. Here we show evidence for a novel molecular mechanism of the PDIM-mediated virulence in M. tuberculosis. We characterized the DNA interaction and the regulon of Rv3167c, a transcriptional repressor that is involved in virulence regulation of M. tuberculosis, and discovered that it controls the PDIM operon. A loss-of-function genetic approach showed that PDIM levels directly correlate with the capacity of M. tuberculosis to escape the phagosome and induce host cell necrosis and macroautophagy. In conclusion, our study attributes a novel role of the cell wall lipid PDIM in intracellular host cell modulation, which is important for host cell exit and dissemination of M. tuberculosis. PMID:28270579

  18. Decreased Polysaccharide Feruloylation Compromises Plant Cell Wall Integrity and Increases Susceptibility to Necrotrophic Fungal Pathogens

    Directory of Open Access Journals (Sweden)

    Nathan T Reem


    Full Text Available The complexity of cell wall composition and structure determines the strength, flexibility, and function of the primary cell wall in plants. However, the contribution of the various components to cell wall integrity and function remains unclear. Modifications of cell wall composition can induce plant responses known as Cell Wall Integrity control. In this study, we used transgenic expression of the fungal feruloyl esterase AnFAE to examine the effect of post-synthetic modification of Arabidopsis and Brachypodium cell walls. Transgenic Arabidopsis plants expressing AnFAE showed a significant reduction of monomeric ferulic acid, increased amounts of wall-associated extensins, and increased susceptibility to Botrytis cinerea, compared with wild type. Transgenic Brachypodium showed reductions in monomeric and dimeric ferulic acids and increased susceptibility to Bipolaris sorokiniana. Upon infection, transgenic Arabidopsis and Brachypodium plants also showed increased expression of several defense-related genes compared with wild type. These results demonstrate a role, in both monocot and dicot plants, of polysaccharide feruloylation in plant cell wall integrity, which contributes to plant resistance to necrotrophic pathogens.

  19. Immunoprofiling reveals unique cell-specific patterns of wall epitopes in the expanding Arabidopsis stem. (United States)

    Hall, Hardy C; Cheung, Jingling; Ellis, Brian E


    The Arabidopsis inflorescence stem undergoes rapid directional growth, requiring massive axial cell-wall extension in all its tissues, but, at maturity, these tissues are composed of cell types that exhibit markedly different cell-wall structures. It is not clear whether the cell-wall compositions of these cell types diverge rapidly following axial growth cessation, or whether compositional divergence occurs at earlier stages in differentiation, despite the common requirement for cell-wall extensibility. To examine this question, seven cell types were assayed for the abundance and distribution of 18 major cell-wall glycan classes at three developmental stages along the developing inflorescence stem, using a high-throughput immunolabelling strategy. These stages represent a phase of juvenile growth, a phase displaying the maximum rate of stem extension, and a phase in which extension growth is ceasing. The immunolabelling patterns detected demonstrate that the cell-wall composition of most stem tissues undergoes pronounced changes both during and after rapid extension growth. Hierarchical clustering of the immunolabelling signals identified cell-specific binding patterns for some antibodies, including a sub-group of arabinogalactan side chain-directed antibodies whose epitope targets are specifically associated with the inter-fascicular fibre region during the rapid cell expansion phase. The data reveal dynamic, cell type-specific changes in cell-wall chemistry across diverse cell types during cell-wall expansion and maturation in the Arabidopsis inflorescence stem, and highlight the paradox between this structural diversity and the uniform anisotropic cell expansion taking place across all tissues during stem growth.

  20. [Heterocysts with reduced cell walls in populations of cycad cyanobionts]. (United States)

    Baulina, O I; Lobakova, E S


    The ultrastructure of the cyanobionts of the greenhouse-grown cycads Cycads circinalis, Ceratozamia mexicana, and Encephalartos villosus was studied. In addition to heterocysts with the typical ultrastructure, the cyanobiont microcolonies also contained altered heterocysts with reduced cell walls, which might dominate in all regions of the coralloid roots. The altered heterocysts represented a protoplast enclosed in a heterocyst-specific envelope with additional layers. Some heterocysts contained an additional reticular protoplast-enclosing sheath below the heterocyst-specific envelope, whereas the other heterocysts contained an additional electron-opaque outer layer. The substance of the inner sheath of the former heterocysts resembled the polysaccharides of mucilage, which fills the intercellular space of plant tissues, whereas the electron-opaque outer layer of the latter heterocysts probably had a protein nature. The substances that constitute the sheath and the outer layer are likely to be synthesized intracellularly and then released with the aid of membrane-bounded vesicles or by channels in the cytoplasmic membrane.

  1. Modifications of Saccharomyces pastorianus cell wall polysaccharides with brewing process. (United States)

    Bastos, Rita; Coelho, Elisabete; Coimbra, Manuel A


    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.

  2. Serologic response to cell wall mannoproteins and proteins of Candida albicans. (United States)

    Martínez, J P; Gil, M L; López-Ribot, J L; Chaffin, W L


    The cell wall of Candida albicans not only is the structure in which many biological functions essential for the fungal cells reside but also is a significant source of candidal antigens. The major cell wall components that elicit a response from the host immune system are proteins and glycoproteins, the latter being predominantly mannoproteins. Both the carbohydrate and protein moieties are able to trigger immune responses. Although cell-mediated immunity is often considered to be the most important line of defense against candidiasis, cell wall protein and glycoprotein components also elicit a potent humoral response from the host that may include some protective antibodies. Proteins and glycoproteins exposed at the most external layers of the wall structure are involved in several types of interactions of fungal cells with the exocellular environment. Thus, coating of fungal cells with host antibodies has the potential to influence profoundly the host-parasite interaction by affecting antibody-mediated functions such as opsonin-enhanced phagocytosis and blocking the binding activity of fungal adhesins for host ligands. In this review, the various members of the protein and glycoprotein fraction of the C. albicans cell wall that elicit an antibody response in vivo are examined. Although a number of proteins have been shown to stimulate an antibody response, for some of these species the response is not universal. On the other hand, some of the studies demonstrate that certain cell wall antigens and anti-cell wall antibodies may be the basis for developing specific and sensitive serologic tests for the diagnosis of candidasis, particularly the disseminated form. In addition, recent studies have focused on the potential for antibodies to cell wall protein determinants to protect the host against infection. Hence, a better understanding of the humoral response to cell wall antigens of C. albicans may provide the basis for the development of (i) effective procedures

  3. XIAP acts as a switch between type I and type II FAS-induced apoptosis signalling (United States)

    Jost, Philipp J.; Grabow, Stephanie; Gray, Daniel; McKenzie, Mark D.; Nachbur, Ueli; Huang, David C.S.; Bouillet, Philippe; Thomas, Helen E.; Borner, Christoph; Silke, John; Strasser, Andreas; Kaufmann, Thomas


    FAS (APO-1/CD95) and its physiological ligand, FASL, regulate apoptotic death of unwanted or dangerous cells in many tissues, functioning as a guardian against autoimmunity and cancer development1-4. Distinct cell types differ in the mechanisms by which the ‘death receptor’ FAS triggers their apoptosis1-4. In type I cells, such as lymphocytes, activation of ‘effector caspases’ by FAS-induced activation of caspase-8 suffices for cell killing whereas in type II cells, including hepatocytes and pancreatic β-cells, amplification of the caspase cascade through caspase-8 mediated activation of the pro-apoptotic BCL-2 family member BID5 is essential6-8. Here we show, that loss of X-chromosome linked inhibitor of apoptosis (XIAP)9,10 function by gene-targeting or treatment with a second mitochondria-derived activator of caspases (SMAC11, also called DIABLO12: direct IAP binding protein with low pI) mimetic drug rendered hepatocytes independent of BID for FAS-induced apoptosis signalling. These results show that XIAP is the critical discriminator between type I versus type II apoptosis signalling and suggest that IAP inhibitors should be used with caution in cancer patients with underlying liver conditions. PMID:19626005

  4. Interaction of Aspergillus with alveolar Type II cells and phagocytes

    NARCIS (Netherlands)

    Escobar Salazar, N.


    Aspergillus species are worldwide distributed fungi and abundant in nature. Aspergilli are mainly saprotrophic obtaining nutrients by degrading dead organic material in particular that of plants. Currently, around 837 species have been reported. Due to the broad range of compound secreted by Aspergi

  5. Genetic modification of plant cell walls to enhance biomass yield and biofuel production in bioenergy crops. (United States)

    Wang, Yanting; Fan, Chunfen; Hu, Huizhen; Li, Ying; Sun, Dan; Wang, Youmei; Peng, Liangcai


    Plant cell walls represent an enormous biomass resource for the generation of biofuels and chemicals. As lignocellulose property principally determines biomass recalcitrance, the genetic modification of plant cell walls has been posed as a powerful solution. Here, we review recent progress in understanding the effects of distinct cell wall polymers (cellulose, hemicelluloses, lignin, pectin, wall proteins) on the enzymatic digestibility of biomass under various physical and chemical pretreatments in herbaceous grasses, major agronomic crops and fast-growing trees. We also compare the main factors of wall polymer features, including cellulose crystallinity (CrI), hemicellulosic Xyl/Ara ratio, monolignol proportion and uronic acid level. Furthermore, the review presents the main gene candidates, such as CesA, GH9, GH10, GT61, GT43 etc., for potential genetic cell wall modification towards enhancing both biomass yield and enzymatic saccharification in genetic mutants and transgenic plants. Regarding cell wall modification, it proposes a novel groove-like cell wall model that highlights to increase amorphous regions (density and depth) of the native cellulose microfibrils, providing a general strategy for bioenergy crop breeding and biofuel processing technology.

  6. Changes in Cell Wall Composition during Ripening of Grape Berries1 (United States)

    Nunan, Kylie J.; Sims, Ian M.; Bacic, Antony; Robinson, Simon P.; Fincher, Geoffrey B.


    Cell walls were isolated from the mesocarp of grape (Vitis vinifera L.) berries at developmental stages from before veraison through to the final ripe berry. Fluorescence and light microscopy of intact berries revealed no measurable change in cell wall thickness as the mesocarp cells expanded in the ripening fruit. Isolated walls were analyzed for their protein contents and amino acid compositions, and for changes in the composition and solubility of constituent polysaccharides during development. Increases in protein content after veraison were accompanied by an approximate 3-fold increase in hydroxyproline content. The type I arabinogalactan content of the pectic polysaccharides decreased from approximately 20 mol % of total wall polysaccharides to about 4 mol % of wall polysaccharides during berry development. Galacturonan content increased from 26 to 41 mol % of wall polysaccharides, and the galacturonan appeared to become more soluble as ripening progressed. After an initial decrease in the degree of esterification of pectic polysaccharides, no further changes were observed nor were there large variations in cellulose (30–35 mol % of wall polysaccharides) or xyloglucan (approximately 10 mol % of wall polysaccharides) contents. Overall, the results indicate that no major changes in cell wall polysaccharide composition occurred during softening of ripening grape berries, but that significant modification of specific polysaccharide components were observed, together with large changes in protein composition. PMID:9808722

  7. 杜仲苷对炎性环境下软骨细胞的增殖和II型胶原蛋白分泌的影响%The Influence of Aucubin on Proliferation of Cartilage Cells and Secretion of Collagen Type II under Inflammatory Environment

    Institute of Scientific and Technical Information of China (English)

    谢国平; 王胜楠; 姜楠


    目的:观察杜仲苷对IL-1β刺激大鼠体外软骨细胞的增殖及II型胶原蛋白分泌的影响。方法:利用IL-1β刺激建立体外大鼠软骨细胞炎性模型,实验分为空白组、IL-1β组、10μM杜仲苷组、100μM杜仲苷组、500μM杜仲苷组、1000μM杜仲苷组;空白组加入10%FBS培养液,IL-1β组加入10ng/mL IL-1β+10%FBS培养液,4个不同浓度杜仲苷组分别加入10μM、100μM、500μM、1000μM杜仲苷+10ng/mL IL-1β+10%FBS培养液,分别培养48小时,采用CCK8检测软骨细胞增殖活力及II型胶原蛋白的分泌。结果:IL-1β组的OD值低于空白组(P<0.05);4个不同浓度杜仲苷组的OD值均高于IL-1β组(P<0.05),且存在一定的量效关系;4个不同浓度杜仲苷组的II型胶原蛋白表达均高于IL-1β组(P<0.05),且存在有一定的量效关系。结论:杜仲苷可以提高体外大鼠软骨细胞炎性环境下的增殖活力,促进II型胶原蛋白的分泌,表明杜仲苷对体外大鼠软骨细胞有一定的抗炎保护作用。%Objective:To observe the influence of aucubin on the proliferation of vitro cartilage cells from IL-1βstimulated rats and their secretion of collagen type II. Methods:Using IL-1βstimulation to establish inflammatory model of vitro cartilage cells with rats, then divided into control group, IL-1β group, 10μMaucubin group, 100μMaucubin group, 500μMaucubin group and 1000μMaucubin group; 10% FBS medium was put in control group, while 10ng/mL IL-1β+10%FBS medium were in IL-1βgroup, and 10μM、100μM、500μM、1000μMaucubin+10ng/mL IL-1β+10%FBS medi-um were respectively in the four different concentration aucubin groups, all the groups were cultured for 48 hours, and used CCK8 to test prolifera-tion activity of cartilage cells and secretion of collagen type II. Results:The OD value of IL-1βgroup was lower than that of control group (P<0.05);the OD value of four different concetration aucubin groups were

  8. Immunogold localization of xyloglucan and rhamnogalacturonan I in the cell walls of suspension-cultured sycamore cells. (United States)

    Moore, P J; Darvill, A G; Albersheim, P; Staehelin, L A


    PLANT CELL WALLS SERVE SEVERAL FUNCTIONS: they impart rigidity to the plant, provide a physical and chemical barrier between the cell and its environment, and regulate the size and shape of each cell. Chemical studies have provided information on the biochemical composition of the plant cell walls as well as detailed knowledge of individual cell wall molecules. In contrast, very little is known about the distribution of specific cell wall components around individual cells and throughout tissues. To address this problem, we have produced polyclonal antibodies against two cell wall matrix components; rhamnogalacturonan I (RG-I), a pectic polysaccharide, and xyloglucan (XG), a hemicellulose. By using the antibiodies as specific markers we have been able to localize these polymers on thin sections of suspension-cultured sycamore cells (Acer pseudoplatanus). Our results reveal that each molecule has a unique distribution. XG is localized throughout the entire wall and middle lamella. RG-I is restricted to the middle lamella and is especially evident in the junctions between cells. These observations indicate that plant cell walls may have more distinct chemical (and functional?) domains than previously envisaged.

  9. Cripto forms a complex with activin and type II activin receptors and can block activin signaling (United States)

    Gray, Peter C.; Harrison, Craig A.; Vale, Wylie


    Activin, nodal, Vg1, and growth and differentiation factor 1 are members of the transforming growth factor β superfamily and signal via the activin type II (ActRII/IIB) and type I (ALK4) serine/threonine kinase receptors. Unlike activins, however, signaling by nodal, Vg1, and growth and differentiation factor 1 requires a coreceptor from the epidermal growth factor-Cripto-FRL1-Cryptic protein family such as Cripto. Cripto has important roles during development and oncogenesis and binds nodal or related ligands and ALK4 to facilitate assembly of type I and type II receptor signaling complexes. Because Cripto mediates signaling via activin receptors and binds directly to ALK4, we tested whether transfection with Cripto would affect the ability of activin to signal and/or interact with its receptors. Here we show that Cripto can form a complex with activin and ActRII/IIB. We were unable to detect activin binding to Cripto in the absence of ActRII/IIB, indicating that unlike nodal, activin requires type II receptors to bind Cripto. If cotransfected with ActRII/IIB and ALK4, Cripto inhibited crosslinking of activin to ALK4 and the association of ALK4 with ActRII/IIB. In addition, Cripto blocked activin signaling when transfected into either HepG2 cells or 293T cells. We have also shown that under conditions in which Cripto facilitates nodal signaling, it antagonizes activin. Inhibition of activin signaling provides an additional example of a Cripto effect on the regulation of signaling by transforming growth factor-β superfamily members. Because activin is a potent inhibitor of cell growth in multiple cell types, these results provide a mechanism that may partially explain the oncogenic action of Cripto. PMID:12682303

  10. Lipid Transfer Proteins Enhance Cell Wall Extension in TobaccoW⃞ (United States)

    Nieuwland, Jeroen; Feron, Richard; Huisman, Bastiaan A.H.; Fasolino, Annalisa; Hilbers, Cornelis W.; Derksen, Jan; Mariani, Celestina


    Plant cells are enclosed by a rigid cell wall that counteracts the internal osmotic pressure of the vacuole and limits the rate and direction of cell enlargement. When developmental or physiological cues induce cell extension, plant cells increase wall plasticity by a process called loosening. It was demonstrated previously that a class of proteins known as expansins are mediators of wall loosening. Here, we report a type of cell wall–loosening protein that does not share any homology with expansins but is a member of the lipid transfer proteins (LTPs). LTPs are known to bind a large range of lipid molecules to their hydrophobic cavity, and we show here that this cavity is essential for the cell wall–loosening activity of LTP. Furthermore, we show that LTP-enhanced wall extension can be described by a logarithmic time function. We hypothesize that LTP associates with hydrophobic wall compounds, causing nonhydrolytic disruption of the cell wall and subsequently facilitating wall extension. PMID:15937228

  11. Aspen Tension Wood Fibers Contain β-(1---> 4)-Galactans and Acidic Arabinogalactans Retained by Cellulose Microfibrils in Gelatinous Walls. (United States)

    Gorshkova, Tatyana; Mokshina, Natalia; Chernova, Tatyana; Ibragimova, Nadezhda; Salnikov, Vadim; Mikshina, Polina; Tryfona, Theodora; Banasiak, Alicja; Immerzeel, Peter; Dupree, Paul; Mellerowicz, Ewa J


    Contractile cell walls are found in various plant organs and tissues such as tendrils, contractile roots, and tension wood. The tension-generating mechanism is not known but is thought to involve special cell wall architecture. We previously postulated that tension could result from the entrapment of certain matrix polymers within cellulose microfibrils. As reported here, this hypothesis was corroborated by sequential extraction and analysis of cell wall polymers that are retained by cellulose microfibrils in tension wood and normal wood of hybrid aspen (Populus tremula × Populus tremuloides). β-(1→4)-Galactan and type II arabinogalactan were the main large matrix polymers retained by cellulose microfibrils that were specifically found in tension wood. Xyloglucan was detected mostly in oligomeric form in the alkali-labile fraction and was enriched in tension wood. β-(1→4)-Galactan and rhamnogalacturonan I backbone epitopes were localized in the gelatinous cell wall layer. Type II arabinogalactans retained by cellulose microfibrils had a higher content of (methyl)glucuronic acid and galactose in tension wood than in normal wood. Thus, β-(1→4)-galactan and a specialized form of type II arabinogalactan are trapped by cellulose microfibrils specifically in tension wood and, thus, are the main candidate polymers for the generation of tensional stresses by the entrapment mechanism. We also found high β-galactosidase activity accompanying tension wood differentiation and propose a testable hypothesis that such activity might regulate galactan entrapment and, thus, mechanical properties of cell walls in tension wood.

  12. Phenylalanine ammonia-lyase and cell wall peroxidase are cooperatively involved in the extensive formation of ferulate network in cell walls of developing rice shoots. (United States)

    Wakabayashi, Kazuyuki; Soga, Kouichi; Hoson, Takayuki


    The relationship between the formation of cell wall-bound ferulic acid (FA) and diferulic acid (DFA) and the change in activities of phenylalanine ammonia-lyase (PAL) and cell wall-bound peroxidase (CW-PRX) was studied in rice shoots. The length and the fresh mass of shoots increased during the growth period from day 4 to 6, while coleoptiles ceased elongation growth on day 5. The amounts of FA and DFA isomers as well as cell wall polysaccharides continued to increase during the whole period. The activities of PAL and CW-PRX greatly increased in the same manner during the period. There were close correlations between the PAL activity and ferulate content or between the CW-PRX activity and DFA content. The expression levels of investigated genes for PAL and putative CW-PRX showed good accordance with the activities of these enzymes. These results suggest that increases in PAL and CW-PRX activities are cooperatively involved in the formation of ferulate network in cell walls of rice shoots and that investigated genes may be, at least in part, associated with the enzyme activities. The substantial increase in such network probably causes the maturation of cell walls and thus the cessation of elongation growth of coleoptiles.

  13. A new picture of cell wall protein dynamics in elongating cells of Arabidopsis thaliana: Confirmed actors and newcomers

    Directory of Open Access Journals (Sweden)

    Jamet Elisabeth


    Full Text Available Abstract Background Cell elongation in plants requires addition and re-arrangements of cell wall components. Even if some protein families have been shown to play roles in these events, a global picture of proteins present in cell walls of elongating cells is still missing. A proteomic study was performed on etiolated hypocotyls of Arabidopsis used as model of cells undergoing elongation followed by growth arrest within a short time. Results Two developmental stages (active growth and after growth arrest were compared. A new strategy consisting of high performance cation exchange chromatography and mono-dimensional electrophoresis was established for separation of cell wall proteins. This work allowed identification of 137 predicted secreted proteins, among which 51 had not been identified previously. Apart from expected proteins known to be involved in cell wall extension such as xyloglucan endotransglucosylase-hydrolases, expansins, polygalacturonases, pectin methylesterases and peroxidases, new proteins were identified such as proteases, proteins related to lipid metabolism and proteins of unknown function. Conclusion This work highlights the CWP dynamics that takes place between the two developmental stages. The presence of proteins known to be related to cell wall extension after growth arrest showed that these proteins may play other roles in cell walls. Finally, putative regulatory mechanisms of protein biological activity are discussed from this global view of cell wall proteins.

  14. Growth regulation mechanisms in higher plants under microgravity conditions - changes in cell wall metabolism. (United States)

    Hoson, T; Kamisaka, S; Wakabayashi, K; Soga, K; Tabuchi, A; Tokumoto, H; Okamura, K; Nakamura, Y; Mori, R; Tanimoto, E; Takeba, G; Nishitani, K; Izumi, R; Ishioka, N; Kamigaichi, S; Aizawa, S; Yoshizaki, I; Shimazu, T; Fukui, K


    During Space Shuttle STS-95 mission, we cultivated seedlings of rice (Oryza sativa L. cv. Koshihikari and cv. Tan-ginbozu) and Arabidopsis (Arabidopsis thaliana L. cv. Columbia and cv. etr1-1) for 68.5, 91.5, and 136 hr on board, and then analyzed changes in the nature of their cell walls, growth, and morphogenesis under microgravity conditions. In space, elongation growth of both rice coleoptiles and Arabidopsis hypocotyls was stimulated. Also, the increase in the cell wall extensibility, especially that in the irreversible extensibility, was observed for such materials. The analyses of the amounts, the structure, and the physicochemical properties of the cell wall constituents indicated that the decreases in levels and molecular masses of cell wall polysaccharides were induced under microgravity conditions, which appeared to contribute to the increase in the wall extensibility. The activity of certain wall enzymes responsible for the metabolic turnover of the wall polysaccharides was increased in space. By the space flight, we also confirmed the occurrence of automorphogenesis of both seedlings under microgravity conditions; rice coleoptiles showed an adaxial bending, whereas Arabidopsis hypocotyls elongated in random directions. Furthermore, it was shown that spontaneous curvatures of rice coleoptiles in space were brought about uneven modifications of cell wall properties between the convex and the concave sides.

  15. Anhydrobiosis in yeast: cell wall mannoproteins are important for yeast Saccharomyces cerevisiae resistance to dehydration. (United States)

    Borovikova, Diana; Teparić, Renata; Mrša, Vladimir; Rapoport, Alexander


    The state of anhydrobiosis is linked with the reversible delay of metabolism as a result of strong dehydration of cells, and is widely distributed in nature. A number of factors responsible for the maintenance of organisms' viability in these conditions have been revealed. This study was directed to understanding how changes in cell wall structure may influence the resistance of yeasts to dehydration-rehydration. Mutants lacking various cell wall mannoproteins were tested to address this issue. It was revealed that mutants lacking proteins belonging to two structurally and functionally unrelated groups (proteins non-covalently attached to the cell wall, and Pir proteins) possessed significantly lower cell resistance to dehydration-rehydration than the mother wild-type strain. At the same time, the absence of the GPI-anchored cell wall protein Ccw12 unexpectedly resulted in an increase of cell resistance to this treatment; this phenomenon is explained by the compensatory synthesis of chitin. The results clearly indicate that the cell wall structure/composition relates to parameters strongly influencing yeast viability during the processes of dehydration-rehydration, and that damage to cell wall proteins during yeast desiccation can be an important factor leading to cell death. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Critical cell wall hole size for lysis in Gram-positive bacteria (United States)

    Mitchell, Gabriel; Wiesenfeld, Kurt; Nelson, Daniel; Weitz, Joshua


    Gram-positive bacteria transport molecules necessary for their survival through holes in their cell wall. The holes in cell walls need to be large enough to let critical nutrients pass through. However, the cell wall must also function to prevent the bacteria's membrane from protruding through a large hole into the environment and lysing the cell. As such, we hypothesize that there exists a range of cell wall hole sizes that allow for molecule transport but prevent membrane protrusion. Here we develop and analyze a biophysical theory of the response of a Gram-positive cell's membrane to the formation of a hole in the cell wall. We predict a critical hole size in the range 15-24nm beyond which lysis occurs. To test our theory, we measured hole sizes in Streptococcus pyogenes cells undergoing enzymatic lysis via transmission electron microscopy. The measured hole sizes are in strong agreement with our theoretical prediction. Together, the theory and experiments provide a means to quantify the mechanisms of death of Gram-positive cells via enzymatically mediated lysis and provides insight into the range of cell wall hole sizes compatible with bacterial homeostasis.

  17. Photometric and Spectroscopic Properties of Type II-P Supernovae


    Faran, Tamar; Poznanski, Dovi; Filippenko, Alexei V.; Chornock, Ryan; Foley, Ryan J.; Ganeshalingam, Mohan; Leonard, Douglas C.; Li, Weidong; Modjaz, Maryam; Nakar, Ehud; Serduke, Frank J. D.; Silverman, Jeffrey M.


    We study a sample of 23 Type II Plateau supernovae (SNe II-P), all observed with the same set of instruments. Analysis of their photometric evolution confirms that their typical plateau duration is 100 days with little scatter, showing a tendency to get shorter for more energetic SNe. The rise time from explosion to plateau does not seem to correlate with luminosity. We analyze their spectra, measuring typical ejecta velocities, and confirm that they follow a well behaved power-law decline. W...

  18. Perinatal lethal type II osteogenesis imperfecta: a case report. (United States)

    Ayadi, Imene Dahmane; Hamida, Emira Ben; Rebeh, Rania Ben; Chaouachi, Sihem; Marrakchi, Zahra


    We report a new case of osteogenesis imperfecta (OI) type II which is a perinatal lethal form. First trimester ultrasound didn't identified abnormalities. Second trimester ultrasound showed incurved limbs, narrow chest, with hypomineralization and multiple fractures of ribs and long bones. Parents refused pregnancy termination; they felt that the diagnosis was late. At birth, the newborn presented immediate respiratory distress. Postnatal examination and bone radiography confirmed the diagnosis of OI type IIA. Death occurred on day 25 of life related to respiratory failure.

  19. Type II reaction without erythema nodosum leprosum masquerading as lymphoma. (United States)

    Mahajan, Rahul; Dogra, Sunil; Kaur, Inderjeet; Yadav, Savita; Saikia, Uma Nahar; Budania, Anil


    Lepromatous leprosy is a multisystem disease that can involve many organ systems, with lymph nodes a common extra-cutaneous site to be affected. Rarely, multibacillary leprosy can be confused with other diseases like lymphomas and connective tissue diseases. Herein we report a patient of lepromatous leprosy with Type II lepra reaction involving lymph nodes who presented with generalised lymphadenopathy, acquired ichthyosis and constitutional symptoms but no cutaneous lesions to suggest erythema nodosum leprosum, and who was initially misdiagnosed as a case of Hodgkin's lymphoma.

  20. Progress in MBE grown type-II superlattice photodiodes (United States)

    Hill, Cory J.; Li, Jian V.; Mumolo, Jason M.; Gunapala, Sarath D.


    We report on the status of GaSb/InAs type-II superlattice diodes grown and fabricated at the Jet Propulsion Laboratory designed for infrared absorption in the 8-12(mu)m range. Recent devices have produced detectivities as high as 8x10 to the tenth power Jones with a differential resistance-area product greater than 6 Ohmcm(sup 2) at 80K with a long wavelength cutoff of approximately 12(mu)m. The measured quantum efficiency of these front-side illuminated devices is close to 30% in the 10-11(mu)m range without antireflection coatings.

  1. Superoxide generation in extracts from isolated plant cell walls is regulated by fungal signal molecules. (United States)

    Kiba, A; Miyake, C; Toyoda, K; Ichinose, Y; Yamada, T; Shiraishi, T


    ABSTRACT Fractions solubilized with NaCl from cell walls of pea and cowpea plants catalyzed the formation of blue formazan from nitroblue tetrazolium. Because superoxide dismutase decreased formazan production by over 90%, superoxide anion (O(2) ) may participate in the formation of formazan in the solubilized cell wall fractions. The formazan formation in the fractions solubilized from pea and cowpea cell walls was markedly reduced by exclusion of NAD(P)H, manganese ion, or p-coumaric acid from the reaction mixture. The formazan formation was severely inhibited by salicylhydroxamic acid and catalase, but not by imidazole, pyridine, quinacrine, and diphenyleneiodonium. An elicitor preparation from the pea pathogen Mycosphaerella pinodes enhanced the activities of formazan formation nonspecifically in both pea and cowpea fractions. The suppressor preparation from M. pinodes inhibited the activity in the pea fraction in the presence or absence of the elicitor. In the cowpea fraction, however, the suppressor did not inhibit the elicitor-enhanced activity, and the suppressor alone stimulated formazan formation. These results indicated that O(2) generation in the fractions solubilized from pea and cowpea cell walls seems to be catalyzed by cell wall-bound peroxidase(s) and that the plant cell walls alone are able to respond to the elicitor non-specifically and to the suppressor in a species-specific manner, suggesting the plant cell walls may play an important role in determination of plant-fungal pathogen specificity.

  2. Altered cell wall properties are responsible for ammonium-reduced aluminium accumulation in rice roots. (United States)

    Wang, Wei; Zhao, Xue Qiang; Chen, Rong Fu; Dong, Xiao Ying; Lan, Ping; Ma, Jian Feng; Shen, Ren Fang


    The phytotoxicity of aluminium (Al) ions can be alleviated by ammonium (NH4(+)) in rice and this effect has been attributed to the decreased Al accumulation in the roots. Here, the effects of different nitrogen forms on cell wall properties were compared in two rice cultivars differing in Al tolerance. An in vitro Al-binding assay revealed that neither NH4(+) nor NO3(-) altered the Al-binding capacity of cell walls, which were extracted from plants not previously exposed to N sources. However, cell walls extracted from NH4(+)-supplied roots displayed lower Al-binding capacity than those from NO3(-)-supplied roots when grown in non-buffered solutions. Fourier-transform infrared microspectroscopy analysis revealed that, compared with NO3(-)-supplied roots, NH4(+)-supplied roots possessed fewer Al-binding groups (-OH and COO-) and lower contents of pectin and hemicellulose. However, when grown in pH-buffered solutions, these differences in the cell wall properties were not observed. Further analysis showed that the Al-binding capacity and properties of cell walls were also altered by pHs alone. Taken together, our results indicate that the NH4(+)-reduced Al accumulation was attributed to the altered cell wall properties triggered by pH decrease due to NH4(+) uptake rather than direct competition for the cell wall binding sites between Al(3+) and NH4(+).

  3. Malignant transformation of ectopic pancreatic cells in the duodenal wall

    Institute of Scientific and Technical Information of China (English)

    Roberto; Bini; Paolo; Voghera; Alberto; Tapparo; Raffaele; Nunziata; Andrea; Demarchi; Matteo; Capocefalo; Renzo; Leli


    Ectopic pancreas (EP) is the relatively uncommon presence of pancreatic tissue outside the normal location of the pancreas. This condition is usually asymptomatic and rarely complicated by pancreatitis and malignant transformation. A few cases of neoplastic phenomena that developed from EP into the duodenal wall are described in the literature. Herein we report a case of gastric outlet obstruction due to adenocarcinoma arising from EP of the duodenal wall. The patient underwent a Whipple's procedure and had...

  4. Navigating the transcriptional roadmap regulating plant secondary cell wall deposition

    Directory of Open Access Journals (Sweden)

    Steven Grant Hussey


    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.

  5. Inhibition of Mycobacterium tuberculosis topoisomerase I by m-AMSA, a eukaryotic type II topoisomerase poison. (United States)

    Godbole, Adwait Anand; Ahmed, Wareed; Bhat, Rajeshwari Subray; Bradley, Erin K; Ekins, Sean; Nagaraja, Valakunja


    m-AMSA, an established inhibitor of eukaryotic type II topoisomerases, exerts its cidal effect by binding to the enzyme-DNA complex thus inhibiting the DNA religation step. The molecule and its analogues have been successfully used as chemotherapeutic agents against different forms of cancer. After virtual screening using a homology model of the Mycobacterium tuberculosis topoisomerase I, we identified m-AMSA as a high scoring hit. We demonstrate that m-AMSA can inhibit the DNA relaxation activity of topoisomerase I from M. tuberculosis and Mycobacterium smegmatis. In a whole cell assay, m-AMSA inhibited the growth of both the mycobacteria.

  6. 77 FR 60124 - Draft Guidance for Industry on Initial Completeness Assessments for Type II Active Pharmaceutical... (United States)


    ... Assessments for Type II Active Pharmaceutical Ingredient Drug Master Files Under the Generic Drug User Fee... Amendments of 2012 (GDUFA), holders of certain drug master files, namely, Type II active...

  7. Altered cell wall disassembly during ripening of Cnr tomato fruit: implications for cell adhesion and fruit softening

    DEFF Research Database (Denmark)

    Orfila, C.; Huisman, M.M.H.; Willats, William George Tycho;


    The Cnr (Colourless non-ripening) tomato (Lycopersicon esculentum Mill.) mutant has an aberrant fruit-ripening phenotype in which fruit do not soften and have reduced cell adhesion between pericarp cells. Cell walls from Cnr fruit were analysed in order to assess the possible contribution of pectic...... polysaccharides to the non-softening and altered cell adhesion phenotype. Cell wall material (CWM) and solubilised fractions of mature green and red ripe fruit were analysed by chemical, enzymatic and immunochemical techniques. No major differences in CWM sugar composition were detected although differences were...... that was chelator-soluble was 50% less in Cnr cell walls at both the mature green and red ripe stages. Chelator-soluble material from ripe-stage Cnr was more susceptible to endo-polygalacturonase degradation than the corresponding material from wild-type fruit. In addition, cell walls from Cnr fruit contained...

  8. Comparative characterization of stromal vascular cells derived from three types of vascular wall and adipose tissue. (United States)

    Yang, Santsun; Eto, Hitomi; Kato, Harunosuke; Doi, Kentaro; Kuno, Shinichiro; Kinoshita, Kahori; Ma, Hsu; Tsai, Chi-Han; Chou, Wan-Ting; Yoshimura, Kotaro


    Multipotent stem/progenitor cells localize perivascularly in many organs and vessel walls. These tissue-resident stem/progenitor cells differentiate into vascular endothelial cells, pericytes, and other mesenchymal lineages, and participate in physiological maintenance and repair of vasculatures. In this study, we characterized stromal vascular cells obtained through the explant culture method from three different vessel walls in humans: arterial wall (ART; >500 μm in diameter), venous wall (VN; >500 μm in diameter), and small vessels in adipose tissue (SV; arterioles and venules, adipose-derived stem/stromal cells (ASCs). All stromal vascular cells of different origins presented fibroblast-like morphology and we could not visually discriminate one population from another. Flow cytometry showed that the cultured population heterogeneously expressed a variety of surface antigens associated with stem/progenitor cells, but CD105 was expressed by most cells in all groups, suggesting that the cells generally shared the characteristics of mesenchymal stem cells. Our histological and flow cytometric data suggested that the main population of vessel wall-derived stromal vascular cells were CD34(+)/CD31(-) and came from the tunica adventitia and areola tissue surrounding the adventitia. CD271 (p75NTR) was expressed by the vasa vasorum in the VN adventitia and by a limited population in the adventitia of SV. All three populations differentiated into multiple lineages as did ASCs. ART cells induced the largest quantity of calcium formation in the osteogenic medium, whereas ASCs showed the greatest adipogenic differentiation. SV and VN stromal cells had greater potency for network formation than did ART stromal cells. In conclusion, the three stromal vascular populations exhibited differential functional properties. Our results have clinical implications for vascular diseases such as arterial wall calcification and possible applications to regenerative therapies

  9. Rice Brittleness Mutants: A Way to Open the 'Black Box' of Monocot Cell Wall Biosynthesis

    Institute of Scientific and Technical Information of China (English)

    Baocai Zhang; Yihua Zhou


    Rice is a model organism for studying the mechanism of cell wall biosynthesis and remolding in Gramineae.Mechanical strength is an important agronomy trait of rice(Oryza sativa L.)plants that affects crop lodging and grain yield.As a prominent physical property of cell walls,mechanical strength reflects upon the structure of different wall polymers and how they interact.Studies on the mechanisms that regulate the mechanical strength therefore consequently results in uncovering the genes functioning in cell wall biosynthesis and remodeling.Our group focuses on the study of isolation of brittle culm(bc)mutants and characterization of their corresponding genes.To date,several bc mutants have been reported.The identified genes have covered several pathways of cell wall biosynthesis,revealing many secrets of monocot cell wall biosynthesis.Here,we review the progress achieved in this research field and also highlight the perspectives in expectancy.All of those lend new insights into mechanisms of cell wall formation and are helpful for harnessing the waste rice straws for biofuel production.

  10. Evidence for land plant cell wall biosynthetic mechanisms in charophyte green algae

    DEFF Research Database (Denmark)

    Mikkelsen, Maria Dalgaard; Harholt, Jesper; Ulvskov, Peter


    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...... 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...

  11. Effect of commercial enzymes on berry cell wall deconstruction in the context of intravineyard ripeness variation under winemaking conditions

    DEFF Research Database (Denmark)

    Gao, Yu; Fangel, Jonatan Ulrik; Willats, William George Tycho;


    at the berry cell wall polymer level and occurred within the experimental vineyard block. Furthemore, all enzyme treatments reduced cell wall variation via depectination. Interestingly, cell wall esterification levels were unaffected by enzyme treatments. This study provides clear evidence that enzymes can...

  12. Closed tachyon solitons in type II string theory

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Etxebarria, Inaki [Max Planck Institute for Physics, Munich (Germany); Montero, Miguel [Instituto de Fisica Teorica IFT-UAM/CSIC, C/Nicolas Cabrera 13-15, Universidad Autonoma de Madrid (Spain); Departamento de Fisica Teorica, Universidad Autonoma de Madrid (Spain); Uranga, Angel M. [Instituto de Fisica Teorica IFT-UAM/CSIC, C/Nicolas Cabrera 13-15, Universidad Autonoma de Madrid (Spain)


    Type II theories can be described as the endpoint of closed string tachyon condensation in certain orbifolds of supercritical type 0 theories. In this paper, we study solitons of this closed string tachyon and analyze the nature of the resulting defects in critical type II theories. The solitons are classified by the real K-theory groups KO of bundles associated to pairs of supercritical dimensions. For real codimension 4 and 8, corresponding to KO(S{sup 4}) = Z and KO(S{sup 8}) = Z, the defects correspond to a gravitational instanton and a fundamental string, respectively. We apply these ideas to reinterpret the worldsheet GLSM, regarded as a supercritical theory on the ambient toric space with closed tachyon condensation onto the CY hypersurface, and use it to describe charged solitons under discrete isometries. We also suggest the possible applications of supercritical strings to the physical interpretation of the matrix factorization description of F-theory on singular spaces. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Corneal lesion as the initial manifestation of tyrosinemia type II. (United States)

    Tsai, Chun-Pin; Lin, Pei-Yu; Lee, Ni-Chung; Niu, Dau-Ming; Lee, Shui-Mei; Hsu, Wen-Ming


    Tyrosinemia type II (Richner-Hanhart syndrome) is a rare autosomal recessive disease with deficiency of tyrosine aminotransferase and subsequently increasing level of serum tyrosine. We report the case of a 2-year-old girl who was referred due to bilateral corneal lesions. Slit-lamp examination showed small granular white deposits arranged in a dendritic pattern in the superficial central cornea of both eyes. Physical examination revealed painful, non-pruritic, hyperkeratotic plaques on the soles, palms and fingertips. Mental evaluation demonstrated developmental delay for her age. Blood examination revealed serum tyrosine level to be 1868 microM (normal range, 30-110 microM), which decreased to 838 microM with 2-month diet on tyrosine and phenylalanine restriction. The corneal and skin lesions resolved completely. However, the corneal deposits recurred a month later as her mother failed to strictly control the diet because the little girl was losing weight and activity. With specific formula and adjusted diet regimen, the corneal lesions decreased again. Corneal pseudodendritic deposits may be the initial manifestation in patients with tyrosinemia type II. Early diagnosis and intervention with diet control are crucial for preventing permanent visual and developmental deficits. Corneal deposits can be one of the parameters in monitoring the efficacy of diet control.

  14. Type-II superlattice photodiodes: an alternative for VLWIR detection (United States)

    Brown, Gail J.; Houston, Shanee; Szmulowicz, Frank; Mahalingam, Krishnamur; Haugan, Heather; Wei, Yajun; Gin, Aaron; Razeghi, Manijeh


    In the very long wavelength infrared (VLWIR) band, λ>14 microns, the detector materials are currently limited to extrinsic semiconductors. These extrinsic materials can be either heavily doped bulk semiconductor, like silicon or germanium, or a doped quantum well heterostructure. An alternative choice that provides the opportunity for higher temperature operation for VLWIR sensing is an intrinsic material based on a type-II InAs/Ga(In)Sb superlattice. There are many possible designs for these superlattices which will produce the same narrow band gap by adjusting individual layer thicknesses, indium content or substrate orientation. The infrared properties of various compositions and designs of these type-II superlattices have been studied. In the past few years, excellent results have been obtained on photoconductive and photodiode samples designed for infrared detection beyond 15 microns. An overview of the status of this material system will be presented. In addition, the latest experimental results for superlattice photodiodes with cut-off wavelengths as long as 30 microns will be covered.


    Directory of Open Access Journals (Sweden)



    Full Text Available BACKGROUND: Sudarshana kriya is a Sanskrit term meaning ―proper vision, purified action by controlling the breath. Kri means to act with awareness. It normalizes breathing by concentrating on it systematically. MATERIAL AND METHODS: 40 subjects with type II diabetes 20 males, 20 females with age group of 40-60 were chosen. They underwent sudarshana kriya training for 6 days organized in Bangalore. A written consent was taken from subjects. They participated in 6 day Sudarshana kriya training held at Bangalore by a trained teacher. This 6 day training includes Sudarshana kriya and meditation. Our Study is designed to study the glycemic control and antilipemic effect of Sudarshana kriya in TypeII Diabetes Mellitus. RESULTS: Sudarshana kriya appears to be specialized pranayamic breathing capable of inducing series of beneficial changes besides causing significant fall of sugar levels, total cholesterol, triglyceride levels (p<0.001 and a raise in HDL cholesterol (p<0.001 CONCLUSION: Sudarshan Kriya can be used along with oral hypoglycemic agents as a holistic adjunct approach for a better glycemic and lipid profile control. Regular practice of Sudarshana Kriya reduces symptoms of mental depression for treating stress and anxiety in post- traumatic stress disorder. Sudarshana Kriya leaves one more alert aware, attentive and focused

  16. Type II intermediate-luminosity optical transients (ILOTs)

    CERN Document Server

    Kashi, Amit


    We propose that in a small fraction of intermediate luminosity optical transients (ILOTs) powered by a strongly interacting binary system, the ejected mass in the equatorial plane can block the central source from our line of sight. We can therefore observe only radiation that is reprocessed by polar outflow, much as in type~II active galactic nuclei (AGN). An ejection of $M_{\\rm ej,e}=10^{-4} ~\\rm{M_\\odot} ~ (1 ~\\rm{M_\\odot})$ at 30 degrees from the equatorial plane and at a velocity of $v_{\\rm e} = 100 ~\\rm{km~s^{-1}}$ will block the central source in the NIR for about 5 years (500 years). During that period of time the object might disappear in the visible band, and be detected only in the IR band due to polar dust. We raise the possibility that the recently observed disappearance of a red giant in the visible, designated N6946-BH1, is a type~II ILOT rather than a failed supernova. For this case we estimate that the ejected mass in the polar direction was $M_{\\rm ej,p}\\approx 10^{-3} ~\\rm{M_\\odot}$. Our sc...

  17. Modeling fluid dynamics on type II quantum computers (United States)

    Scoville, James; Weeks, David; Yepez, Jeffrey


    A quantum algorithm is presented for modeling the time evolution of density and flow fields governed by classical equations, such as the diffusion equation, the nonlinear Burgers equation, and the damped wave equation. The algorithm is intended to run on a type-II quantum computer, a parallel quantum computer consisting of a lattice of small type I quantum computers undergoing unitary evolution and interacting via information interchanges represented by an orthogonal matrices. Information is effectively transferred between adjacent quantum computers over classical communications channels because of controlled state demolition following local quantum mechanical qubit-qubit interactions within each quantum computer. The type-II quantum algorithm presented in this paper describes a methodology for generating quantum logic operations as a generalization of classical operations associated with finite-point group symmetries. The quantum mechanical evolution of multiple qubits within each node is described. Presented is a proof that the parallel quantum system obeys a finite-difference quantum Boltzman equation at the mesoscopic scale, leading in turn to various classical linear and nonlinear effective field theories at the macroscopic scale depending on the details of the local qubit-qubit interactions.

  18. Gravitational Field Shielding by Scalar Field and Type II Superconductors

    Directory of Open Access Journals (Sweden)

    Zhang B. J.


    Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.

  19. Novel dentin phosphoprotein frameshift mutations in dentinogenesis imperfecta type II. (United States)

    Lee, K-E; Kang, H-Y; Lee, S-K; Yoo, S-H; Lee, J-C; Hwang, Y-H; Nam, K H; Kim, J-S; Park, J-C; Kim, J-W


    The dentin sialophosphoprotein (DSPP) gene encodes the most abundant non-collagenous protein in tooth dentin and DSPP protein is cleaved into several segments including the highly phosphorylated dentin phosphoprotein (DPP). Mutations in the DSPP gene have been solely related to non-syndromic form of hereditary dentin defects. We recruited three Korean families with dentinogenesis imperfecta (DGI) type II and sequenced the exons and exon-intron boundaries of the DSPP gene based on the candidate gene approach. Direct sequencing of PCR products and allele-specific cloning of the highly repetitive exon 5 revealed novel single base pair (bp) deletional mutations (c.2688delT and c.3560delG) introducing hydrophobic amino acids in the hydrophilic repeat domain of the DPP coding region. All affected members of the three families showed exceptionally rapid pulp chambers obliteration, even before tooth eruption. Individuals with the c.3560delG mutation showed only mild, yellowish tooth discoloration, in contrast to the affected individuals from two families with c.2688delT mutation. We believe that these results will help us to understand the molecular pathogenesis of DGI type II as well as the normal process of dentin biomineralization.

  20. Unsupervised clustering of Type II supernova light curves

    CERN Document Server

    Rubin, Adam


    As new facilities come online, the astronomical community will be provided with extremely large datasets of well-sampled light curves (LCs) of transient objects. This motivates systematic studies of the light curves of supernovae (SNe) of all types, including the early rising phase. We performed unsupervised k-means clustering on a sample of 59 R-band Type II SN light curves and find that our sample can be divided into three classes: slowly-rising (II-S), fast-rise/slow-decline (II-FS), and fast-rise/fast-decline (II-FF). We also identify three outliers based on the algorithm. We find that performing clustering on the first two components of a principle component analysis gives equivalent results to the analysis using the full LC morphologies. This may indicate that Type II LCs could possibly be reduced to two parameters. We present several important caveats to the technique, and find that the division into these classes is not fully robust and is sensitive to the uncertainty on the time of first light. Moreo...

  1. On the nature of rapidly fading Type II supernovae

    CERN Document Server

    Moriya, Takashi J; Ergon, Mattias; Blinnikov, Sergei I


    It has been suggested that Type II supernovae with rapidly fading light curves (a.k.a. Type IIL supernovae) are explosions of progenitors with low-mass hydrogen-rich envelopes which are of the order of 1 Msun. We investigate light-curve properties of supernovae from such progenitors. We confirm that such progenitors lead to rapidly fading Type II supernovae. We find that the luminosity of supernovae from such progenitors with the canonical explosion energy of 1e51 erg and 56Ni mass of 0.05 Msun can increase temporarily shortly before all the hydrogen in the envelope recombines. As a result, a bump appears in their light curves. The bump appears because the heating from the nuclear decay of 56Ni can keep the bottom of hydrogen-rich layers in the ejecta ionized, and thus the photosphere can stay there for a while. We find that the light-curve bump becomes less significant when we make explosion energy larger (>~ 2e51 erg), 56Ni mass smaller (<~ 0.01 Msun), 56Ni mixed in the ejecta, or the progenitor radius l...

  2. Inert Dark Matter in Type-II Seesaw

    CERN Document Server

    Chen, Chuan-Hung


    Weakly interacting massive particle (WIMP) as a dark matter (DM) candidate is further inspired by recent AMS-02 data, which confirm the excess of positron fraction observed earlier by PAMELA and Fermi-LAT experiments. Additionally, the excess of positron+electron flux is still significant in the measurement of Fermi-LAT. For solving the problem of massive neutrinos and observed excess of cosmic-ray by DM annihilation, we study the model with an inert Higgs doublet (IHD) in the framework of type-II seesaw mechanism by imposing a $Z_2$ symmetry on the IHD, where the lightest particle of IHD is the DM candidate while the neutrino masses origin from the Higgs triplet in type-II seesaw model. We calculate the cosmic-ray production in our model by using three kinds of neutrino mass spectra, classified as normal ordering, inverted ordering and quasi-degeneracy. We find that if leptonic triplet decays are dominant, the observed excess of positron/electron flux could be explained well in normal ordered neutrino mass s...

  3. Type-ii binary superlattices for infrared detector

    Energy Technology Data Exchange (ETDEWEB)

    Razeghi, M.; Mohseni, H. [Northwestern Univ., Evanston (United States); Brown, G. J. [WPAFB, Colombus (United States)


    III-V quantum wells and superlattices based on InAs/GaSb/AlSb, and related compounds have attracted many attentions due to their unique band alignments and physical properties. Recently, novel electronic and optoelectronic heterostructures have been proposed from this material system for hundred gigahertz logic circuits, terahertz transistors. RTDs, infrared lasers, and infrared detectors. In this paper we will describe the ongoing research at the Center for Quantum Devices to develop the theory, modeling, growth, characterization, and device fabrication techniques for this material system. We have demonstarted the first uncooled infrared detectors from type-II superlattices. The measured detectivity is more than 1 x 10{sup 8} cmHz{sup 1/2}/W at 10.6 {mu}m at room temperature which is higher than the commercially available uncooled photon detectors at similar wavelength. In paralle, we have demonstraed the first high-performance p-i-n type-II photodiode in the very long wavelength infrared (VLWIR) range operating at T=80K. The devices with cutoff wavelength of 16 mm showed a responsivity of 3.5 A/W at 80 K leading to a detectivity of {approx}1.51x10{sup 10} cmHz{sup 1/2}/W. Similar devices with cutoff wavelengths up to 25 {mu}m was demonstrated at 80 K. To enhance this technology further, we plan to move from quantum wells to quantum wire and quantum dots.

  4. Fitting the Two-Higgs-Doublet model of type II

    CERN Document Server

    Eberhardt, Otto


    We present the current status of the Two-Higgs-Doublet model of type II. Taking into account all available relevant information, we exclude at $95$% CL sizeable deviations of the so-called alignment limit, in which all couplings of the light CP-even Higgs boson $h$ are Standard-Model-like. While we can set a lower limit of $240$ GeV on the mass of the pseudoscalar Higgs boson at $95$% CL, the mass of the heavy CP-even Higgs boson $H$ can be even lighter than $200$ GeV. The strong constraints on the model parameters also set limits on the triple Higgs couplings: the $hhh$ coupling in the Two-Higgs-Doublet model of type II cannot be larger than in the Standard Model, while the $hhH$ coupling can maximally be $2.5$ times the size of the Standard Model $hhh$ coupling, assuming an $H$ mass below $1$ TeV. The selection of benchmark scenarios which maximize specific effects within the allowed regions for further collider studies is illustrated for the $H$ branching fraction to fermions and gauge bosons. As an exampl...

  5. Characterization of hearing loss in aged type II diabetics. (United States)

    Frisina, Susan T; Mapes, Frances; Kim, SungHee; Frisina, D Robert; Frisina, Robert D


    Presbycusis - age-related hearing loss - is the number one communicative disorder and a significant chronic medical condition of the aged. Little is known about how type II diabetes, another prevalent age-related medical condition, and presbycusis interact. The present investigation aimed to comprehensively characterize the nature of hearing impairment in aged type II diabetics. Hearing tests measuring both peripheral (cochlea) and central (brainstem and cortex) auditory processing were utilized. The majority of differences between the hearing abilities of the aged diabetics and their age-matched controls were found in measures of inner ear function. For example, large differences were found in pure-tone audiograms, wideband noise and speech reception thresholds, and otoacoustic emissions. The greatest deficits tended to be at low frequencies. In addition, there was a strong tendency for diabetes to affect the right ear more than the left. One possible interpretation is that as one develops presbycusis, the right ear advantage is lost, and this decline is accelerated by diabetes. In contrast, auditory processing tests that measure both peripheral and central processing showed fewer declines between the elderly diabetics and the control group. Consequences of elevated blood sugar levels as possible underlying physiological mechanisms for the hearing loss are discussed.

  6. 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


    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. 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.

  7. Investigation on Adsorption of Lithospermum erythrorhizon onto Fungal Cell Wall Polysaccharides

    Institute of Scientific and Technical Information of China (English)

    孟琴; 薛莲


    A culture of Lithosperrnum erythrorhizon adsorbed on fungal cell wall polysaccharides, a novel bioadsorbent made from fungal cell wall, has been established in this paper. Three steps were involved in this immobilization. The first step was preparation of suspended plant cells from tightly aggregated plant cell clumps. The disassembled ratio of 0.715g·g-1 (the disassembled cells over total cells) was obtained under optimum condition for the enzymatic reaction. Then, the adsorption of plant cells onto fungal cell wall polysaccharides was conducted and the saturated capacity of 12g cell per gram of carrier was obtained in adsorption immobilization. Finally, the culture of cells adsorbed on fungal cell wall polysaccharides was compared with that of cells entrapped in alginate or suspension cell culture. While exposed to in situ liquid paraffin extraction coupled with cell culture, the shikonin productivity of immobilized cells by adsorption was 10.67g·L-1, which was 1.8 times of that in suspension culture and 1.5 times of that entrapped in alginate.

  8. Nanostructured carbon electrocatalyst supports for intermediate-temperature fuel cells: Single-walled versus multi-walled structures (United States)

    Papandrew, Alexander B.; Elgammal, Ramez A.; Tian, Mengkun; Tennyson, Wesley D.; Rouleau, Christopher M.; Puretzky, Alexander A.; Veith, Gabriel M.; Geohegan, David B.; Zawodzinski, Thomas A.


    It is unknown if nanostructured carbons possess the requisite electrochemical stability to be used as catalyst supports in the cathode of intermediate-temperature solid acid fuel cells (SAFCs) based on the CsH2PO4 electrolyte. To investigate this application, single-walled carbon nanohorns (SWNHs) and multi-walled carbon nanotubes (MWNTs) were used as supports for Pt catalysts in SAFCs operating at 250 °C. SWNH-based cathodes display greater maximum activity than their MWNT-based counterparts at a cell voltage of 0.8 V, but are unstable in the SAFC cathode as a consequence of electrochemical carbon corrosion. MWNT-based cells are resistant to this effect and capable of operation for at least 160 h at 0.6 V and 250 °C. Cells fabricated with nanostructured carbon supports are more active (52 mA cm-1vs. 28 mA cm-1 at 0.8 V) than state-of-the-art carbon-free formulations while simultaneously displaying enhanced Pt utilization (40 mA mgPt-1vs. 16 mA mgPt-1 at 0.8 V). These results suggest that MWNTs are a viable support material for developing stable, high-performance, low-cost air electrodes for solid-state electrochemical devices operating above 230 °C.

  9. Size, Shape, and Arrangement of Cellulose Microfibril in Higher Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Ding, S. Y.


    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).

  10. The plant cell wall integrity maintenance mechanism-concepts for organization and mode of action. (United States)

    Hamann, Thorsten


    One of the main differences between plant and animal cells are the walls surrounding plant cells providing structural support during development and protection like an adaptive armor against biotic and abiotic stress. During recent years it has become widely accepted that plant cells use a dedicated system to monitor and maintain the functional integrity of their walls. Maintenance of integrity is achieved by modifying the cell wall and cellular metabolism in order to permit tightly controlled changes in wall composition and structure. While a substantial amount of evidence supporting the existence of the mechanism has been reported, knowledge regarding its precise mode of action is still limited. The currently available evidence suggests similarities of the plant mechanism with respect to both design principles and molecular components involved to the very well characterized system active in the model organism Saccharomyces cerevisiae. There the system has been implicated in cell morphogenesis as well as response to abiotic stresses such as osmotic challenges. Here the currently available knowledge on the yeast system will be reviewed initially to provide a framework for the subsequent discussion of the plant cell wall integrity maintenance mechanism. The review will then end with a discussion on possible design principles for the cell wall integrity maintenance mechanism and the function of the plant turgor pressure in this context.

  11. Cell wall degrading enzymes in Trichoderma asperellum grown on wheat bran

    DEFF Research Database (Denmark)

    Bech, Lasse; Busk, Peter Kamp; Lange, Lene


    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....

  12. Structure of ristocetin A in complex with a bacterial cell-wall mimetic


    Nahoum, Virginie; Spector, Sherri; Loll, Patrick J.


    The crystal structure of the complex between ristocetin A and the cell-wall peptide mimetic N-acetyl-lysine-d-alanine-d-alanine has been solved. Structural details explaining the anticooperativity of the antibiotic have been identified.

  13. The Paracoccidioides cell wall: past and present layers towards understanding interaction with the host

    Directory of Open Access Journals (Sweden)

    Rosana ePuccia


    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. Arsenic interception by cell wall of bacteria observed with surface-enhanced Raman scattering. (United States)

    Tian, Haixia; Zhuang, Guoqiang; Ma, Anzhou; Jing, Chuanyong


    The purpose of this study was to determine the interactions between arsenic (As) resistant bacteria and As, using surface-enhanced Raman scattering (SERS) and Fourier transform infrared (FTIR) spectroscopy. According to our 16S rDNA results, eight bacteria isolated from the environment can be identified to four genera (Arthrobacter, Pseudomonas, Sphingomonas, and Acinetobacter). The bacteria were separated into cell wall and protoplast in the study to assess the As(V) attack. The As(V) stress on bacteria could be identified with SERS, but not with FTIR. The bacteria in our study primarily resist As(V) through sequestration of As(V) by the cell wall. The change in SERS peaks and their relationships with cell wall suggested that As(V) mainly interacts with functional groups on the cell wall including polysaccharides and flavin derivates.

  15. Regulation of auxin on secondary cell wall cellulose biosynthesis in developing cotton fibers (United States)

    Cotton (Gossypium hirsutum L.) fibers are unicellular trichomes that differentiate from epidermal cells of developing cotton ovules. Mature fibers exhibit thickened secondary walls composed of nearly pure cellulose. Cotton fiber development is divided into four overlapping phases, 1) initiation sta...

  16. Understanding the relationship between cotton fiber properties and non-cellulosic cell wall polysaccharides

    DEFF Research Database (Denmark)

    Rajasundaram, Dhivyaa; Runavot, Jean-Luc; Guo, Xiaoyuan


    different cotton species were studied. The glycan array was generated by sequential extraction of cell wall polysaccharides from mature cotton fibers and screening samples against eleven extensively characterized cell wall probes. Also, phenotypic characteristics of cotton fibers such as length, strength......A detailed knowledge of cell wall heterogeneity and complexity is crucial for understanding plant growth and development. One key challenge is to establish links between polysaccharide-rich cell walls and their phenotypic characteristics. It is of particular interest for some plant material, like...... and phenotypic traits. In addition, the analysis also identified specific polysaccharides which may play a major role during fiber development for the final fiber characteristics. Three different regression methods identified a negative correlation between micronaire and the xyloglucan and homogalacturonan...

  17. Understanding the relationship between cotton fiber properties and non-cellulosic cell wall polysaccharides

    DEFF Research Database (Denmark)

    Rajasundaram, Dhivyaa; Runavot, Jean-Luc; Guo, Xiaoyuan;


    A detailed knowledge of cell wall heterogeneity and complexity is crucial for understanding plant growth and development. One key challenge is to establish links between polysaccharide-rich cell walls and their phenotypic characteristics. It is of particular interest for some plant material, like...... different cotton species were studied. The glycan array was generated by sequential extraction of cell wall polysaccharides from mature cotton fibers and screening samples against eleven extensively characterized cell wall probes. Also, phenotypic characteristics of cotton fibers such as length, strength...... and phenotypic traits. In addition, the analysis also identified specific polysaccharides which may play a major role during fiber development for the final fiber characteristics. Three different regression methods identified a negative correlation between micronaire and the xyloglucan and homogalacturonan...


    Energy Technology Data Exchange (ETDEWEB)

    Rose, Jocelyn


    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 t